1 End Uses Of Natural Gas
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END USES OF NATURAL GAS
20444_a_A_ppt_07 - END USES OF NATURAL GAS
Contents
The gas chain • • • •
General presentation of the gas chain Gas sources Gas markets Gas end uses
Transport routes
Chemical conversion routes
Positioning and processing requirements for each monetization route
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The Gas Chain PRODUCTION
CONDITIONING/TRANSPORT
PROCESSING
MARKETS
LNG
ENERGY GAS
CNG
-Residential -Industrial -Transport (NGV)
LIQUEFACTION
COMPRESSION PIPE
Others (e.g. hydrates transport)
Raw gas
GTL / FT
PROCESSING
LIQUIDS
CHEMICAL CONVERSION
DME METHANOL
- Fuel oils and lubricants - Methanol - Olefins
Olefins/PP/PE
COMPRESSION
Reinjection (EOR) LPG CONDENSATES
CO2 Hg
N2
O2
H2O
To market / Discharged into natural environment or stored 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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H2S
Source: Total 3
Gas sources: natural gas fields Liquids Gas Field
Non-Associated Gas
Gas Water Associated Gas Petroleum
Non-saturated oil field
Petroleum Water
Dome gas Associated Gas Petroleum Gas Saturated oil field
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Petroleum Water
© 2013 - IFP Training
Liquids
4
Gas sources: natural gas fields Comments on the previous slide Types of field • Pure gas field containing dry gas, probably associated with water, CO2, nitrogen, H2S, helium, mercury… • Non-saturated oil field: containing petroleum with associated gas, and methane molecules that will need to be extracted during wellhead processing. • Saturated oil field: containing gas associated with petroleum and gas in solution. The heaviest dissolved gaseous elements have the same applications as pure gas fields - for LPG, propane, butane…
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When we find gas or petroleum, the information collected during exploratory drilling undergoes comprehensive evaluation. How much gas is there? What is its quality? Is it easy to extract? How much will it cost to develop the field? And finally, the big question: to what extent will the operation be profitable? If the information seems favourable to investors and customers, drilling starts and the gas is extracted.
5
Gas sources: composition of natural gas
LPG Liquefied Petroleum Gas
METHANE
C1
ETHANE
C2
PROPANE BUTANE
C3 C4
PENTANES & HEAVY FRACTIONS: Pentanes plus Natural petrol Condensates Water
Nitrogen
C5+
NGL Natural Gas Liquids
Helium
Impurities CO2
H2S
Mercury
...
Gas quality has a major economic impact.
• The presence of impurities entails higher processing costs, thereby reducing the profitability of a gas project. 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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• The presence of heavy components (LPG, condensate) improves the profitability of a gas project.
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Gas sources: composition of natural gas Comments on the previous slide
Why the gas is processed: the natural gas emerging from the ground is not the “clean” gas delivered to consumers. Oil fields contain dissolved gas or gas in the form of a pocket separate from the liquid. Gas deposits generally contain hydrocarbons heavier than methane, and those that are liquid at ambient temperature are known as natural gas liquids.
To be eligible for consumption, and partly for transport purposes, the gas must have certain essential characteristics: • it must be DRY: containing no WATER or HYDROCARBONS in liquid state • its acidic components and toxic bodies must be eliminated • it must have constant heating value and specific gravity, Wobbe index © 2013 - IFP Training
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Gas sources: composition of natural gas
Natural gas quality: some semantics • • • • •
Lean (Dry) Gas Rich (Wet) Gas Sour Gas Highly (Very) Sour Gas Acid Gas
• Sweet Gas • Low Cal Gas
Low NGL content High NGL content Presence of CO2 and/or H2S High CO2 and/or H2S content Acidic gases separated from natural gas (H2S+CO2) Gas scrubbed clean of acidic constituents High CO2 / N2 content
Comments Gases with high NGL content are generally gases associated with a liquid hydrocarbon deposit. Raw gas from a natural or associated gas deposit may contain acidic impurities: H2S and/or CO2, in greater or lesser quantities.
If the treated gas still contains large quantities of CO2 or nitrogen, it has a low heating value.
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Sweetening these sour raw gases produces a treated or sweet gas and separated acid gases (H2S and CO2 present in the raw gas). This separated acid gas is generally sent to a sulphur production unit (Claus unit) but can also be reinjected.
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Gas markets: energy gas
Gas as an energy source • Fuel: − Residential and commercial − Industrial: heating, steam production, gas turbines
• Raw material for electricity production − Thermal power stations
• Fuel for transport − NGV: Natural Gas for Vehicles (but limited impact: 60 MMscfd for 500,000 vehicles)
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When the consumer market is a long way away, costly transport is required
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Gas markets: energy gas Comments on the previous slide
Gas is mainly used as a fuel: • for residential and commercial use (heating) • for industrial use (heating, steam production, feeding gas turbines to power rotating machines)
It is also used in thermal power stations for electricity production
Natural gas can also be used as a fuel in vehicles’ internal combustion engines. This requires a suitable infrastructure (network of service stations with gas compression), and vehicles equipped with compressed gas tanks.
The gas consumer markets are industrialised countries. Natural gas deposits are generally located a long way from these markets, which means that the gas must be transported. Gas is more expensive to transport than oil: where petroleum can be transported at atmospheric pressure in liquid state, gas must be at high pressure or low temperature to have sufficient specific gravity to make the transport economic. © 2013 - IFP Training
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Gas production, consumption and flows in 2012
COMMENTS
© 2013 - IFP Training
Source : BP Stat Review 2013
Another way to look at the international gas trade, presently donimated by the import to Europe for pipeline gas, and by Japan/Korea for LNG. EP - 20500_b_A_ppt_06 - FUNDAMENTALS OF LIQUEFIED NATURAL GAS (LNG)
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Gas markets: fuel oils, lubricants and chemicals
Converting the gas into liquid products opens up access to new markets: • The fuel oils and lubricants market − GTL-FT conversion: » Diesel » Naphtha » Lubricants
− Conversion to Dimethyl-Ether (DME) » The DME market is developing in several emerging countries
• The chemicals and petrochemicals markets − Conversion to Methanol − Conversion to Olefins
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Converting gas to liquid products facilitates market access by reducing transport costs, but this involves high investment
12
Gas markets: fuel oils, lubricants and chemicals Comments on the previous slide Chemical conversion of gas into liquid products, with higher molar mass, facilitates its transport.
Gas can be converted into liquid hydrocarbons, gas oil or lubricants, via Fischer-Tropsch conversion.
It can also be converted into DimethylEther. DME is used as a fuel for vehicles, instead of LPG. This requires a suitable infrastructure, which certain emerging countries are putting in place.
Gas can also be chemically converted into methanol, and then possibly into olefins.
Liquid hydrocarbons generally fetch a higher price than natural gas. So the FischerTropsch conversion can also ensure greater profitability of the gas.
On the other hand, chemical conversion facilities are very large and expensive. They are also highly energy-consuming.
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Gas markets: use in hydrocarbon production
Gas is used for enhanced liquid hydrocarbon recovery • EOR (Enhanced Oil Recovery)
Gas is also used to satisfy the internal consumption needs of hydrocarbon production and processing centres • Steam generation • Electricity generation • Powering rotating machines © 2013 - IFP Training
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Gas markets: monetization routes
Domestic gas CONVERSION
TRANSPORT Gas pipeline
GTL/FT
Fuel oils / Lubricants & Chemicals / Petrochemicals markets
DME
Natural or associated gas
LNG
Onshore Offshore
CNG
Energy gas market
NGH METHANOL GTW
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Used by the hydrocarbons producer
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Gas markets: monetization routes Comments on the previous slide
Gas is a low concentration energy (a volume of gas under ambient conditions has approximately 1000 times less energy than the same volume of petroleum), and commercial exploitation of gas resources when there is no nearby domestic market is always confronted with the problem of transporting or converting the gas for sale for end use on a distant market.
The choice of technology to be adopted must be examined on an individual basis, but the main means for transport remain: gas pipeline, LNG (including mini-LNG), GTW (Gas to Wire) i.e. converting the gas into electricity, CNG (Compressed Natural Gas) and NGH (Natural Gas Hydrates). The target end markets are the gas and/or electricity markets.
As regards conversion, with petrochemicals and fuels as the end markets, the currently feasible means are: methanol and GTL, and DME (DiMethyl Ether).
Historically, the first target market was gas and energy, via pipelines and LNG, but the attraction of the liquid markets - bigger, more flexible and with higher added value – has driven the development of these new technologies. © 2013 - IFP Training
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Contents
The gas chain
Transport routes • • • • •
Gas pipeline Liquefied gas (LNG) Compressed gas (CNG) Transport in the form of hydrates (NGH) Gas to wire (GTW)
Chemical conversion routes
Positioning and processing requirements for each monetization route
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Gas pipeline: principle
The mostly used transport route
A gas pipeline comprises: • a transport pipe • compression stations
Gas pipelines
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Recompression stations Collection
Processing Terminal - storage
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Gas pipeline: principle Comments on the previous slide
Gas pipelines were the first equipment used for transporting gas over long distances from the production site to the consumption site. A gas pipeline essentially comprises a gas transport line and compression stations designed to compensate for pressure losses due to gas friction as it flows.
A gas pipeline chain comprises the following stages: • •
• • • • • •
This mature and simple technology poses the following drawbacks: incompressible investment, geopolitical risks associated with the countries crossed, difficulty in installing new pipelines in highly urbanised areas and technical feasibilities (trenches, seismic hazard zones)
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collection of effluent from the various wells processing of the gas produced to bring it up to the transport specifications: separation of the heaviest hydrocarbons and dehydration to prevent risks of condensation, hydrate formation and corrosion; this treatment may be supplemented by sweetening gas compression if the wellhead pressure is insufficient (especially in the deposit depletion phase) transport through the pipeline recompression during transport, for long distances, to prevent an excessive pressure drop any additional processing to bring the gas up to the distribution specifications storage and transfer to the distribution network distribution of the gas.
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Gas pipeline: sizing
Flowrate (MSm3/h)
SIZING OF MAIN GAS PIPELINE
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Length without recompression (km)
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Gas pipeline: sizing Comments on the previous slide
This graph suffices to determine an initial sizing estimate for transporting gas via pipelines.
Based on the chart on the right and the pre-determined hypotheses, for lengths without recompression between 100 and 1000 km, and pipe diameters of between 24’’ and 56’’, a gas pipeline can transport up to 6-7 MSm3/h, i.e. approximately 5500 MMscfd.
Note that beyond 48’’, pipelines must adhere to local legislation. Currently, only Russia permits pipeline diameters of 56’’.
Similarly, the maximum pressure in an onshore pipeline is limited by the country’s legislation. Generally, the maximum value is 80 bar. Exemptions have been granted up to 100 bar, following negotiations with the authorities.
© 2013 - IFP Training
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Gas pipeline: selection criteria
Advantages • • • • • •
Important orders of magnitude:
• Consumption of 1 % per 1000 km Mature • 1.5 to 2 kT CO2/MMBoe Relatively simple Efficient, and low CO2 emissions No restrictive specifications Economical for short distances Applicable to all types of reserves in principle
Drawbacks Location constraints highly case dependent Long-term fixed transport installation Sensitivity to geopolitical risk Not economical over long distances
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• • • •
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LNG: the LNG chain
Liquefaction, transport and regasification • Train capacities: from 1 to 8 MTPA • Transport: atmospheric pressure and T=-160° °C • 1 m3 of LNG = 580 Sm3 of natural gas
© 2013 - IFP Training
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LNG: the LNG chain Comments on the previous slide
Liquefaction is a technology used for condensing natural gas, with a high volume reduction factor: 580 m3 of natural gas per m3 of LNG. The gas is transported in liquid form at atmospheric pressure and at a temperature close to - 160° °C. The quantities used by an LNG project are always large (> 3 3 MTPA, i.e. 4.5 billion m /year), and generally supply regasification terminals serving national distribution networks, except for Japan, where certain terminals only supply power stations.
An LNG transport chain comprises the following main stages: • • • • • • •
This mature technology has the following advantages: greater flexibility than pipelines, high efficiency. On the drawbacks side, it is highly capital-intensive, and requires long-term contracts.
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processing and transport by gas pipeline to the coast processing of produced gas to bring it up to the requisite specifications for liquefaction (deep sweetening, dehydration, removal of heavy metals…) liquefaction of gas, possibly accompanied by recovery of Liquefied Petroleum Gases (LPG) for separate end use storage and loading (shipping terminal) transport by methane tankers receival and storage regasification.
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LNG: liquefaction
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With 8 production trains, the plant has reached a capacity of 22.25 MT/year of LNG + 1 Mt/year of LPG + 10 Million b/year of condensates
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LNG: comparative transport costs 5
$/MMBtu
High-cost gas pipeline 4
Low-cost gas pipeline 3
LNG
2
1
Oil tankers
Oil pipeline km
Heavy investment: ($/mmbtu)
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160 0
320 0
400 0
Production: 0. – 2.5 Processing: 0.1 – 0.25 * 3 offshore Transport: 0.5 – 4.5 Distribution: 1.2 – 2.8 TOTAL: 2.1 – 10.5
640 0
800 0
© 2013 - IFP Training
80 0 Comments
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LNG: selection criteria
Advantages • • • • •
Mature, except for offshore LNG (FLNG) Efficient for transport Economical over long distances Storage Flexible for downstream
Important orders of magnitude: CO2 spec of feed gas: CO2 < 50 ppm Liquefaction cons.: 10-15 % Transport cons.: 0.4 %/1000 km Regasification cons.: 0.5-1.5 % Liquefaction emissions: 35-45 CO2/MMboe • NG reserves : large • • • • •
kT
Drawbacks High investment required Tough location and installation constraints CO2 specifications High internal consumption and CO2 emissions Uneconomical over short distances Economical for large gas reserves
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• • • • • •
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CNG: principle
Pressure (bar.a)
m3 gas/m3 transported
Vapour
Liquid © 2013 - IFP Training
Temperature (°C) 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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CNG: principle Comments on the previous slide
This graph positions the various CNG technologies in pressure and temperature terms in relation to one another and to LNG. As a reminder, LNG - Liquefied Natural Gas - is a gas condensed at a temperature of – 160°C and at ambient pressure.
8 different CNG technologies - of varying maturity , as we will see later - are currently available on the market. They function in two fairly distinct pressure and temperature ranges. The first, qualified as High Pressure, is associated with ambient temperature, which gives operating pressures for CNG cylinders of approximately 200 to 250 b. The second is a medium pressure region (around 120/130 b) associated with a lower temperature of around –30°C.
The efficiency gain obtained by cooling the gas operates on 2 levels: The volume occupied by the gas is reduced as a function of the temperatures ratio (PV/T = cste)
•
At low temperatures, the behaviour of the gas increasingly diverges from the ideal gas law, the compressibility factor expressed in the formula (PV = nZRT) drops steeply, which results in a steep increase in the compression ratios. Conversely, employing low temperatures makes the whole export chain more complex
•
These combinations can achieve ratios of gas volume under standard conditions to volume transported of 230 to 290 m3/m3. This is to be compared with the ratio of 580/600 obtained for LNG.
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CNG: principle
Gas transported in dense state: • either at ambient temperature and P = 250 bar • or T = – 30° °C and P = 120 bar CNG downstream process
CNG upstream process
CNG fleet
CNG export method
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Unloading system
© 2013 - IFP Training
Loading system
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CNG: principle Comments on the previous slide
The principle of gas transport as CNG is based on obtaining a gas in dense phase state through compression at ambient temperature or low temperature (approx. – 30° °C). The fluid obtained 3 reaches densities of around 150 to 250 kg/m , as compared with 500 kg/m3 for LNG.
The gas is processed upstream in order to achieve the transport and, where relevant, commercial specifications and is then transported (by ship or truck) to the downstream processing site, where it will be transferred to a local market.
This technology seems to be a valid alternative to LNG and pipelines for certain cases (small quantities of gas and short distances) but, as at 2012, there are not yet any operational references for sea transport, although there are land transport references by truck in Argentina, for example.
© 2013 - IFP Training
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CNG: selection criteria
Advantages • No very restrictive specifications • Makes short distances economical • Offshore production
Important orders of magnitude • Km 0 consumption: 12% • Transport consumption: 1%/1000 km • Total emissions over 2000 km: 30 kT CO2/MMboe • NG reserves : low, average
Drawbacks • No commercial application with transport by ship in 2012 • Inefficient for transport • High costs © 2013 - IFP Training
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Transport in the form of hydrates (NGH): principle
After CNG, now let’s look at methane hydrates as a gas transport solution. With CNG, the gas is compressed to concentrate it; with liquefaction we turn it into a liquid through condensation; and with hydrates we turn it into a solid by trapping gas molecules in crystalline water structures. The diagram positions the hydrate formation region in pressure regions of around 40/50 bar and at positive temperatures. Then the hydrates are cooled and the pressure returned practically to ambient pressure. A metastability phenomenon revealed by the Norwegians enables hydrates to be kept stable for transportation. 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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Comments
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Transport in the form of hydrates (NGH): principle
Gas transport in solid form: • at atmospheric pressure and T = – 20° °C
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Major drawback: transport of 85% water (by mass)
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Transport in the form of hydrates (NGH): principle Comments on the previous slide
Natural gas hydrates offer a means of storing large quantities of gas with a volume reduction factor of around 180 (less advantageous than LNG – 600 - and CNG – 300 on average). They are also stable under normal conditions. NGH consists in using gas hydrates to transport the gas in solid form at atmospheric pressure and at a temperature of approximately – 20° °C. It is defined by the following stages: •
Production: the gas from a field is injected into a reactor at a temperature of approx. 10° °C and a pressure of 60 bar where, in contact with water, it will be trapped in the form of hydrates.
•
Transport: the hydrates are transferred to a ship and transported from the production site to the distribution site.
•
Regasification: close to the distribution market, the hydrates are dissociated and the gas is distributed.
NGH is immature and does not seem to have great potential, in the short term at least.
© 2013 - IFP Training
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Transport in the form of hydrates (NGH): selection criteria
Advantages • Transport pressure
at
atmospheric
Drawbacks
Important orders of magnitude • Km 0 cons.: 4-5 % • Transport cons.: 3 %/1000 km • Total emissions over 3000 km: 50 kT CO2/MMBoe • NG reserves : very small
• Immature, industrial feasibility not proven. 2015-2020 deadline? • Transports 85% water (by mass) • Inefficient • High costs • Very low gas reserves © 2013 - IFP Training
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Gas to wire (GTW): principle
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Gas to wire (GTW): principle Comments on the previous slide
One of the solutions for transferring medium quantities of gas to the markets is to convert it into electricity. This technology, dubbed GTW (Gas to Wire), has numerous advantages: •
electricity is the energy source most easily usable by the consumer and also offers significant growth prospects
•
deregulation of the electricity market in many countries offers the opportunity to become a producer
•
using gas as a fuel makes GTW an ecologically clean sector
•
the cycles used are efficient compared to other means of electricity production.
GTW also has drawbacks: given the large quantities of electricity produced, you need a market able to provide outlets for it. In many potentially GTW candidate countries, the local market can only absorb a small proportion of the electricity produced. The rest must be transported over distances of thousands of km, which is costly, involves substantial losses and exposes the installations to sabotage.
•
a power station requires a stable supply chain over a period of at least 20 years. A gas production profile associated with oil production often peaks before rapidly falling. So GTW will be more suitable for natural gas deposits.
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•
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GTW: combined cycle power station
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GTW: combined cycle power station Comments on the previous slide
The combined cycle uses the heat from the gas turbine exhaust gases to generate steam, which expands in a turbine until it condenses. Hence the power of the gas turbine is increased by one third and the net overall ISO efficiency may reach 58%. The main parts in a combined cycle are the gas turbine, the recovery boiler, the steam turbine, the condenser and electricity generator.
The condenser uses ambient air or water to condense the steam; the choice of condenser type depends on the local water resource, and directly influences the combined cycle performance.
A combined cycle brings numerous advantages: • • •
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• • • • •
high efficiency, i.e. electricity production at minimum costs partial-load operation can be optimised by adjusting the power station configuration (3*33 % or 2*50 %) high availability (92% on average over a year) if the maintenance program, concentrated within the offpeak period, is observed flexibility of use, especially with the Single-shaft configuration small workforce (54 people for a 1260-MW power station) investment cost lower than for a steam power station short construction time (25 months for a standard module) lower atmospheric emissions
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Gas to wire (GTW): efficiency
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Gas to wire (GTW): efficiency Comments on the previous slide Continuous transport of electrical energy
DC (direct current) transport has numerous advantages over AC (alternating current) transport: • • • • •
lower line installation cost smaller line losses possible interconnection of networks operating at different frequencies continuity of service in case of failure highly flexible operation
Conversely, the major drawback of DC transport is the obligation to install at each line-end an AC/DC conversion station, which is expensive (approx. $175 million (in 2000) for 1000 MW in +/500 kV). However, beyond a certain transport distance, the savings generated by the lower installation cost of a DC line compensate for the expense of building conversion stations. © 2013 - IFP Training
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GTW: combined cycle organisation BangBo - ABB/Alsthom technology • • • • •
Cooling tower Water treatment Discharge water Heat recovery steam generator Gas compressor
• • • • •
Gas inlet Fuel storage Clean water tank HV zone Turbine buildings
© 2013 - IFP Training
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Gas to wire (GTW): selection criteria
Advantages Mature technology Attractive thermal efficiency and costs Open electricity market Rapid implementation (construction 2 years) • Operating flexibility • No special constraints • • • •
Important orders of magnitude • 1 MSm3/d gas = 250 MWe (combined cycle) • Electricity generation efficiency (combined cycle): ~ 50 % • NG reserves : small
Drawbacks
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• Economical for capacities < 1000 MW • Not economical over long distances (> 1500-2000 km) • Very high surface area of AC/DC and DC/AC conversion stations
44
Contents
Gas chain
Transport routes
Chemical conversion routes • Fischer-Tropsch (GTL/FT) • DiMethyl-Ether (DME) • Methanol and other chemical sectors
Positioning and processing requirements for each monetization route
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Chemical conversions
© 2013 - IFP Training
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Chemical conversions Comments on the previous slide
Another way of commercialising natural gas is to chemically convert it into liquid products, more easily transportable under ambient conditions. There are various methods, but the first stage common to every case is conversion of natural gas into synthesis gas with catalysts (SMR, ATR, catalytic POx) or without catalysts (gas POx), a mixture of carbon monoxide (CO) and hydrogen (H2). The H2/CO ratio of the synthesis gas produced must differ according to the target end product.
The products examined in this study are: • • •
the Fischer-Tropsch process, producing Diesel and naphtha methanol DME: only the direct process is examined here, as it maximises energy efficiency
These differ widely in terms of target markets and their size. The technical constraints (process, location, etc.) vary.
For information, the optimum stoichiometric ratios at the synthesis gas production outlet are as follows: GTL/FT: H2/CO = 1.7 for iron-based catalysts and H2/CO = 2 for cobalt-based catalysts Direct DME: H2/CO = 1 Methanol H2-CO2 / CO + CO2 = 2
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• • •
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GTL/FT: brief history
1920
1940 1924
German discovery Conversion of CO & H2 into hydrocarbon
F.Fischer & H.Tropsch
1935
WWII
1960 1955
1980 1980-82
2000 1990-2000
2006 2007
1993 1st Industrial FT Atmospheric fixed bed reactor - Rhurchemie
SASOL I Iron Medium Pressure Synthesis commercialized by Rhurchemie and Lurgi (8,000 BPD)
9 FT Plants built in Germany Support German petroleum independency during WWII (~16,000BPD)
SASOL II & III 150,000 BPD plant in South Africa, Fe catalyst and Circulating Fluidized Bed Reactor
ORYX (QP+SASOLChevron) 34,000 BPD plant in Qatar Co Cat. Slurry Reactors.
Synthol CFB Reactors
WWII German Low Pressure Reactors
ARGE Fixed Bed Reactor
SHELL BINTULU 12,500 BPD plant in Malaysia, Co catalyst Fixed Bed Reactor
PEARL (QP+SHELL) 2x70,000 BPD plant in Qatar - Co Cat. Fixed bed Reactors.
© 2013 - IFP Training
Patent granted to Fischer & Tropsch
SASOL Dev. of “Advanced Synthol Process” SASOL II & III Reactors Replacement
Source: Total 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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GTL/FT: principle
Production of liquid hydrocarbons from natural gas in 3 stages: • Synthesis gas generation - highly endothermic • Fischer-Tropsch synthesis - highly exothermic • upgrading Light HC (used as fuel H2O and/or O2
Fields
Pretreatment
Synthesis gas generation
Steam
FischerTropsch synthesis
gas or syngas load)
Waxes and
Hydro-treatment condensates Hydro-cracking
Water
(+ lube bases)
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Local or transport
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Diesel + Paraffin naphtha
MARKETS: Local or transport Petrochemicals
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GTL/FT: principle Comments on the previous slide
Chemical conversion of natural gas via Fischer Tropsch synthesis, often known as GTL/FT, produces liquid hydrocarbons such as gas oil or kerosene. It follows the three main stages below: •
conversion into synthesis gas (“syngas”), a mix of carbon monoxide and hydrogen
•
Fischer Tropsch synthesis: primarily paraffin-like, very long carbon chain compounds, known as waxes
•
upgrading into lighter hydrocarbons by means of hydro-treatment units, to obtain primarily diesel (75%) and naphtha (25 %).
A successful GTL chain necessarily means integrating the three units, and this demands highly specialised know-how.
This highly capital-intensive technology has few operational references, low efficiency and high CO2 emissions, but it opens up access to the huge fuels market.
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GTL/FT: synthesis gas generation
1.
SMR
Boiler zone
S/C > 2.5 T: 850-900°C P ~ 20 bar H2/CO ~ 4.8 flue gas
Prerefor mer
Radiant zone (naked flames / tubes filled with catalyst)
steam Desulphurised natural gas (ppb’s S)
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air
synthesis gas to process
fuel gas 51
GTL/FT: synthesis gas generation
2.
POX
S/C < 0.2 T ~ 1350°C P ~ 60 bar H2/CO <1.9 Advantages:
Constraints:
High conversion High CO/CO2 selectivity H2/CO ratio close to optimum for F-T Need for additional SMR High outlet T Air separation plant
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GTL/FT: synthesis gas generation
3.
ATR S/C ~ 1.2 T ~ 1050°C P ~ 20-50 bar H2/CO ~2.6
Combining POX and catalytic reforming
Constraints:
CO2 recycling, F-T purge Air separation plant
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N.B. there is air ATR, with constraints downstream due to high nitrogen load
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GTL/FT: the Fischer-Tropsch stage Main reaction
n CO + 2n H2 -(CH2)n- + nH2O + n x 165 kJ
primarily: mix of paraffins C1->C200 olefins alcohols, acids, oxygenated solvents volume water ~ volume HC no sulphur or aromatics
Catalyst: iron based or cobalt based Reactor: multi-tube fixed bed or “slurry” 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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Technological options
54
GTL/FT: selection criteria
Advantages • Usable over a wide range of capacities • Efficient to transport • No market constraint
Important orders of magnitude • • • •
H2S < 0.1 ppm Energy efficiency: 42-52% Emissions: 150 kT CO2/Mmboe NG reserves : average to large
Drawbacks
Oryx Sasol /QP: 34,000 bpd 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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• H2S specifications • High energy consumption and high CO2 emissions • High technical cost (compared to other types of conversion) • Complexity due to various types of product
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DME: principle
Two processes:
Pilot Plant in JFE Tsurumi Factory
• direct conversion or via methanol
Two different markets: • chemicals ( olefins) and energy (fuel for vehicles)
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DME: principle Comments on the previous slide
Today’s global DiMethylEther (DME) market represents 150,000 tonnes per year, and encompasses aerosol applications, particularly in the field of cosmetics. Since this application is already mature and the market very small, DME could be used as diesel fuel in appropriate engines (clean gas fuel), as fuel in energy production turbines or in domestic applications. With the chemical formula CH3O-CH3, DME is gaseous under normal conditions and its physical characteristics are very similar to those of LPG.
There are two types of process for synthesising DME, either directly, or via methanol as the intermediary.
The direct process optimises energy efficiency: the potential maximum efficiency (65-70%) appears to be the best of the conversion processes.
There are a host of technology licensors for the indirect process: TOPSOE, LURGI, TEC and MGC. At present, only JFE fully masters the direct process. © 2013 - IFP Training
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DME: selection criteria
Advantages • Lower CO2 emissions than GTL/FT • Single product • Possibility of mixing with LPG
Important orders of magnitude • • • •
H2S < 0.1 ppm Energy efficiency: 60% Emissions: 75 kT CO2/MMboe NG reserves : small
DME is supplied from 100t/d Demonstration Plant at Kushiro
Drawbacks
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• H2S specifications • Immature: no commercial installation in 2011 (one in project) • Markets to be developed
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Methanol: principle
3 stages: • Synthesis gas generation • Methanol synthesis • Distillation
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Methanol: principle Comments on the previous slide
Methanol is the simplest alcohol, with chemical composition CH3-OH, and is used primarily as a base compound in the chemicals industry. Methanol fuel is very little used at present. The main outlet today (approx. ¾ of worldwide production) is in the manufacture of chemicals, primarily formaldehyde. Then comes manufacture of MTBE (approx. 1/4 of the market), an additive added to petrol to increase its octane rating. It is synthesised in three stages, as in the case of Fischer Tropsch synthesis: • • •
synthesis gas production methanol synthesis purification of end product
For the moment the methanol route is essentially limited by the market size.
The first cases of a methanol production rate exceeding 1000 t/d date back to the 1980s. The plants are located chiefly in gas-producing countries. © 2013 - IFP Training
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From gas to plastics: principle
4 stages: • • • •
synthesis gas generation methanol or DME synthesis conversion into olefins (MTO / DTO) polymerisation Integrated MTO - PE-PP
Natural gas Coal
Methanol Plant MTO
Syngas Plant
indirect
direct
DME Plant
+ OCP Plant
Polyethylene Plant Polypropylene Plant
Source: Total Petrochemicals
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MTO: Methanol to Olefins DTO: Dimethylether to Olefins OCP: Olefin Cracking Process
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Methanol: selection criteria
Advantages
• Mature • More efficient and lower CO2 emissions than GTL/FT • The cheapest of the conversion routes • Single product
Important orders of magnitude • • • •
H2S < 0.1 ppm Energy efficiency: 65% Emissions: 75 kT CO2/Mmboe NG reserves : small
Drawbacks
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• H2S specifications • Market constraint: economy of scale required, but difficult due to the tight market
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Contents
The gas chain
Transport
Chemical conversion
Positioning and processing requirements for each monetization route © 2013 - IFP Training
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Positioning for each monetization route Reserves
10 TCF
5 TCF
0
GAS PIPELINE LNG CNG DME MeOH Distances to 500 market
GTL 1000
10 000 km
GAS PIPELINE LNG CNG GTL / MeOH / DME: distance to market: no real impact Energy Eff.
50 %
60 %
70 %
90 %
80 % LNG CNG
GTL 20444_a_A_ppt_07 - END USES OF NATURAL GAS
MeOH
DME
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GAS PIPELINE
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Positioning for each monetization route Comments on the previous slide
Gas pipelines transport medium-to-high volumes of gas over distances of thousands of km. They remain a rigid solution, sensitive to geopolitical risks. They are also limited by geographical constraints (e.g. ocean trenches).
To transport gas over very long distances, LNG is the most economical solution but as it is expensive, the economy requires high volumes of gas.
CNG is more suitable for small volumes of gas and short distances (up to 1,000 km).
The conversion processes all have lower energy efficiencies than the transport alternatives. The market for the Fischer-Tropsch method products is not limited, unlike the DME and methanol method markets which are very limited.
© 2013 - IFP Training
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Commercial specifications of gas
Interchangeability: measured by Wobbe index 3 categories of countries for gases: Specific gravity of methane = 0.555
IW =
PCS dgaz dair
Asian Countries RICH GASES
Specific gravity for black flue gas = 0.7
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United States and United Kingdom: LEAN GASES
European countries: future EASEE-gas standard
© 2013 - IFP Training
Nitrogen
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Commercial specifications of gas Comments on the previous slide
There are several kinds of commercial specifications: • • •
toxicity and corrosion (max. content of oxygen and sulphur-based compounds) formation of hydrates and liquid (water and hydrocarbons dew point) interchangeability
Interchangeability characterises the composition thresholds and properties of the gases, to ensure satisfactory operation of devices running on gas, and is measured by the Wobbe index. It is important this should remain as constant as possible. We therefore give an upper and lower threshold value for this index, and combustion emissions can be controlled, burner efficiency is improved and the operating conditions of this equipment are secured.
This positioning enables us to determine the type of composition possible for an H type gas (high heating value): so lean gases will contain little C3+ and may have relatively large proportions of nitrogen. Gases for Japan, on the other hand, must be low in N2 and rich in ethane and propane.
Certain gases, known as L gases (low heating value), contain more inert gas and have Wobbe index values below 47 MJ/Nm3, and so are not interchangeable with any current specifications. This is the case for certain fields in Thailand and the Groningen gas reserves in the Netherlands, for example. So with very little or no pre-treatment, these gases must be distributed in a different network.
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Technological specifications
3 families of routes for the H2S/CO2 grid 4 3
2 H2S, total S or H2S+COS specifications
1
0
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EASEE-gas: H2S+COS < 3 ppm and total sulphur < 19 ppm L gas: CO2 spec at 25% mol for the Thai network for example
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Technological specifications Comments on the previous slide
It is important to stress that the EASEE-gas H2S specification is more precisely a specification limiting H2S + COS to 3 ppm.
Gas monetization routes fall into three categories: •
LNG, for which the constraints are both technological (CO2 which must be removed to prevent it from crystallising and clogging the equipment in cryogenic zones) and commercial
•
the conversion routes, where there is no reason for commercial gas specifications, leaving only H2S content, which is highly restrictive (H2S is poisonous to the catalysts used, even at low concentration)
•
gas pipelines, CNG and methane hydrates: only commercial specifications (H2S, CO2) are genuinely restrictive.
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Quiz True The gas chain includes a gas treatment stage, followed by transport to the consumer markets.
False
●
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………….…..
It also includes a gas conditioning stage (compression, liquefaction) for ‘transport’ to the energy gas markets, or a chemical conversion stage for conversion before the transport stage.
All technologies involving chemical conversion of the gas start with a synthesis gas generation stage
●
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… Yes. The synthesis gas is then converted into liquid hydrocarbons (GTL-FT), methanol or DME. …………………………………………………….…..
LNG is more economic than gas pipeline transport over distances of more than 3,000 km.
●
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… True, insofar as it is possible to transport the gas by sea; otherwise land transport of large quantities of LNG is impossible. …………………………………………………………………………………………………………………………………………….…..
All gas liquefaction plants are located on the coast
●
………………..…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………….….. Liquefied gas is effectively transported over long distances in methane tankers. If the gas deposit is far from the coast, it is preferable
to transport gas in a pipeline as far as the coast, and liquefy it at the methane tanker loading site.
Conversion of gas into DME has good energy efficiency, better than GTL-FT and equivalent to that of LNG
●
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………….…..……..
DME is more energy-efficient than GTL-FT (70% vs. 60%), but less efficient than LNG (80-85% efficiency)
CNG can be used to exploit very large gas reserves (more than 5 Tcf), but over relatively short distances (< 1000 km)
●
……..
CNG is denser than LNG ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………….….. False. The specific gravity of LNG is 580 times denser than gas under standard conditions; the specific gravity of CNG is between 295 ..and
320 times that of gas under standard conditions, depending on the CNG process used.
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●
© 2013 - IFP Training
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… No, CNG is suitable for medium-sized gas reserves (less than 2 Tcf), over relatively short distances. ……………………………………………………………….…..
70
Key points to remember The gas chain comprises several stages: production and processing, conditioning or chemical conversion, and transport to the consumer markets.
The gas markets are generally a long distance away from the production sites.
Gas may be transported by means of a gas pipeline (gaseous at ambient temperature and at high pressure), by methane tankers (liquid at – 160°C and atmospheric pressure) or under intermediate conditions (CNG).
Chemical conversion enables us to reach the fuel oils and lubricants markets (GTL/FT, DME) or the chemicals market, while facilitating transport – but at the cost of major investment.
The monetization route must be selected on an individual basis, according to the markets available and the economy of each route (dependent on the size of the reserves, the product value and the transport cost).
Gas processing must be suited to the monetization route, so as to satisfy the commercial specifications of the finished product, but also the technological specifications specific to each route.
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Approximate conversion factors
Chaleur / Energie Heat / Energy Million Btu (MMBtu)
GJ 1
Mcal 250
kWh 300
Flow rate Débit
Volume cubic meter (cm)
Heating Value Valeur Calorifique Btu/cf 1000
cubic feet (cf) 35
Mcal/m3 9
Million cubic feet per day (MMcfd) 100
Btu/m3 35 000
Mj/m3 35
Billion cubic meter per year (Bcm/y) 1
kWh/m3 10
Equivalences 1 bep 1 t1charbon t coal
t (LNG) t (GNL)
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m3m3 (LNG) (GNL) 2,5
m3 (gas) m3 (gaz) 1500
MMBtu 53
kWh 15 000
m3 m3(gas) gaz 180 750 © 2013 - IFP Training
Gaz naturel liquéfié Liquefied natural gas
MMBtu gaz 6 25
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Contents
The gas chain • • • •
General presentation of the gas chain Gas sources Gas markets Gas end uses
Transport routes
Chemical conversion routes
Positioning and processing requirements for each monetization route
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2
The Gas Chain PRODUCTION
CONDITIONING/TRANSPORT
PROCESSING
MARKETS
LNG
ENERGY GAS
CNG
-Residential -Industrial -Transport (NGV)
LIQUEFACTION
COMPRESSION PIPE
Others (e.g. hydrates transport)
Raw gas
GTL / FT
PROCESSING
LIQUIDS
CHEMICAL CONVERSION
DME METHANOL
- Fuel oils and lubricants - Methanol - Olefins
Olefins/PP/PE
COMPRESSION
Reinjection (EOR) LPG CONDENSATES
CO2 Hg
N2
O2
H2O
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H2S
Source: Total 3
Gas sources: natural gas fields Liquids Gas Field
Non-Associated Gas
Gas Water Associated Gas Petroleum
Non-saturated oil field
Petroleum Water
Dome gas Associated Gas Petroleum Gas Saturated oil field
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Petroleum Water
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Liquids
4
Gas sources: natural gas fields Comments on the previous slide Types of field • Pure gas field containing dry gas, probably associated with water, CO2, nitrogen, H2S, helium, mercury… • Non-saturated oil field: containing petroleum with associated gas, and methane molecules that will need to be extracted during wellhead processing. • Saturated oil field: containing gas associated with petroleum and gas in solution. The heaviest dissolved gaseous elements have the same applications as pure gas fields - for LPG, propane, butane…
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When we find gas or petroleum, the information collected during exploratory drilling undergoes comprehensive evaluation. How much gas is there? What is its quality? Is it easy to extract? How much will it cost to develop the field? And finally, the big question: to what extent will the operation be profitable? If the information seems favourable to investors and customers, drilling starts and the gas is extracted.
5
Gas sources: composition of natural gas
LPG Liquefied Petroleum Gas
METHANE
C1
ETHANE
C2
PROPANE BUTANE
C3 C4
PENTANES & HEAVY FRACTIONS: Pentanes plus Natural petrol Condensates Water
Nitrogen
C5+
NGL Natural Gas Liquids
Helium
Impurities CO2
H2S
Mercury
...
Gas quality has a major economic impact.
• The presence of impurities entails higher processing costs, thereby reducing the profitability of a gas project. 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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• The presence of heavy components (LPG, condensate) improves the profitability of a gas project.
6
Gas sources: composition of natural gas Comments on the previous slide
Why the gas is processed: the natural gas emerging from the ground is not the “clean” gas delivered to consumers. Oil fields contain dissolved gas or gas in the form of a pocket separate from the liquid. Gas deposits generally contain hydrocarbons heavier than methane, and those that are liquid at ambient temperature are known as natural gas liquids.
To be eligible for consumption, and partly for transport purposes, the gas must have certain essential characteristics: • it must be DRY: containing no WATER or HYDROCARBONS in liquid state • its acidic components and toxic bodies must be eliminated • it must have constant heating value and specific gravity, Wobbe index © 2013 - IFP Training
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Gas sources: composition of natural gas
Natural gas quality: some semantics • • • • •
Lean (Dry) Gas Rich (Wet) Gas Sour Gas Highly (Very) Sour Gas Acid Gas
• Sweet Gas • Low Cal Gas
Low NGL content High NGL content Presence of CO2 and/or H2S High CO2 and/or H2S content Acidic gases separated from natural gas (H2S+CO2) Gas scrubbed clean of acidic constituents High CO2 / N2 content
Comments Gases with high NGL content are generally gases associated with a liquid hydrocarbon deposit. Raw gas from a natural or associated gas deposit may contain acidic impurities: H2S and/or CO2, in greater or lesser quantities.
If the treated gas still contains large quantities of CO2 or nitrogen, it has a low heating value.
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Sweetening these sour raw gases produces a treated or sweet gas and separated acid gases (H2S and CO2 present in the raw gas). This separated acid gas is generally sent to a sulphur production unit (Claus unit) but can also be reinjected.
8
Gas markets: energy gas
Gas as an energy source • Fuel: − Residential and commercial − Industrial: heating, steam production, gas turbines
• Raw material for electricity production − Thermal power stations
• Fuel for transport − NGV: Natural Gas for Vehicles (but limited impact: 60 MMscfd for 500,000 vehicles)
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When the consumer market is a long way away, costly transport is required
9
Gas markets: energy gas Comments on the previous slide
Gas is mainly used as a fuel: • for residential and commercial use (heating) • for industrial use (heating, steam production, feeding gas turbines to power rotating machines)
It is also used in thermal power stations for electricity production
Natural gas can also be used as a fuel in vehicles’ internal combustion engines. This requires a suitable infrastructure (network of service stations with gas compression), and vehicles equipped with compressed gas tanks.
The gas consumer markets are industrialised countries. Natural gas deposits are generally located a long way from these markets, which means that the gas must be transported. Gas is more expensive to transport than oil: where petroleum can be transported at atmospheric pressure in liquid state, gas must be at high pressure or low temperature to have sufficient specific gravity to make the transport economic. © 2013 - IFP Training
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10
Gas production, consumption and flows in 2012
COMMENTS
© 2013 - IFP Training
Source : BP Stat Review 2013
Another way to look at the international gas trade, presently donimated by the import to Europe for pipeline gas, and by Japan/Korea for LNG. EP - 20500_b_A_ppt_06 - FUNDAMENTALS OF LIQUEFIED NATURAL GAS (LNG)
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Gas markets: fuel oils, lubricants and chemicals
Converting the gas into liquid products opens up access to new markets: • The fuel oils and lubricants market − GTL-FT conversion: » Diesel » Naphtha » Lubricants
− Conversion to Dimethyl-Ether (DME) » The DME market is developing in several emerging countries
• The chemicals and petrochemicals markets − Conversion to Methanol − Conversion to Olefins
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Converting gas to liquid products facilitates market access by reducing transport costs, but this involves high investment
12
Gas markets: fuel oils, lubricants and chemicals Comments on the previous slide Chemical conversion of gas into liquid products, with higher molar mass, facilitates its transport.
Gas can be converted into liquid hydrocarbons, gas oil or lubricants, via Fischer-Tropsch conversion.
It can also be converted into DimethylEther. DME is used as a fuel for vehicles, instead of LPG. This requires a suitable infrastructure, which certain emerging countries are putting in place.
Gas can also be chemically converted into methanol, and then possibly into olefins.
Liquid hydrocarbons generally fetch a higher price than natural gas. So the FischerTropsch conversion can also ensure greater profitability of the gas.
On the other hand, chemical conversion facilities are very large and expensive. They are also highly energy-consuming.
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Gas markets: use in hydrocarbon production
Gas is used for enhanced liquid hydrocarbon recovery • EOR (Enhanced Oil Recovery)
Gas is also used to satisfy the internal consumption needs of hydrocarbon production and processing centres • Steam generation • Electricity generation • Powering rotating machines © 2013 - IFP Training
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Gas markets: monetization routes
Domestic gas CONVERSION
TRANSPORT Gas pipeline
GTL/FT
Fuel oils / Lubricants & Chemicals / Petrochemicals markets
DME
Natural or associated gas
LNG
Onshore Offshore
CNG
Energy gas market
NGH METHANOL GTW
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Used by the hydrocarbons producer
15
Gas markets: monetization routes Comments on the previous slide
Gas is a low concentration energy (a volume of gas under ambient conditions has approximately 1000 times less energy than the same volume of petroleum), and commercial exploitation of gas resources when there is no nearby domestic market is always confronted with the problem of transporting or converting the gas for sale for end use on a distant market.
The choice of technology to be adopted must be examined on an individual basis, but the main means for transport remain: gas pipeline, LNG (including mini-LNG), GTW (Gas to Wire) i.e. converting the gas into electricity, CNG (Compressed Natural Gas) and NGH (Natural Gas Hydrates). The target end markets are the gas and/or electricity markets.
As regards conversion, with petrochemicals and fuels as the end markets, the currently feasible means are: methanol and GTL, and DME (DiMethyl Ether).
Historically, the first target market was gas and energy, via pipelines and LNG, but the attraction of the liquid markets - bigger, more flexible and with higher added value – has driven the development of these new technologies. © 2013 - IFP Training
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Contents
The gas chain
Transport routes • • • • •
Gas pipeline Liquefied gas (LNG) Compressed gas (CNG) Transport in the form of hydrates (NGH) Gas to wire (GTW)
Chemical conversion routes
Positioning and processing requirements for each monetization route
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Gas pipeline: principle
The mostly used transport route
A gas pipeline comprises: • a transport pipe • compression stations
Gas pipelines
© 2013 - IFP Training
Recompression stations Collection
Processing Terminal - storage
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Gas pipeline: principle Comments on the previous slide
Gas pipelines were the first equipment used for transporting gas over long distances from the production site to the consumption site. A gas pipeline essentially comprises a gas transport line and compression stations designed to compensate for pressure losses due to gas friction as it flows.
A gas pipeline chain comprises the following stages: • •
• • • • • •
This mature and simple technology poses the following drawbacks: incompressible investment, geopolitical risks associated with the countries crossed, difficulty in installing new pipelines in highly urbanised areas and technical feasibilities (trenches, seismic hazard zones)
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collection of effluent from the various wells processing of the gas produced to bring it up to the transport specifications: separation of the heaviest hydrocarbons and dehydration to prevent risks of condensation, hydrate formation and corrosion; this treatment may be supplemented by sweetening gas compression if the wellhead pressure is insufficient (especially in the deposit depletion phase) transport through the pipeline recompression during transport, for long distances, to prevent an excessive pressure drop any additional processing to bring the gas up to the distribution specifications storage and transfer to the distribution network distribution of the gas.
19
Gas pipeline: sizing
Flowrate (MSm3/h)
SIZING OF MAIN GAS PIPELINE
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Length without recompression (km)
20
Gas pipeline: sizing Comments on the previous slide
This graph suffices to determine an initial sizing estimate for transporting gas via pipelines.
Based on the chart on the right and the pre-determined hypotheses, for lengths without recompression between 100 and 1000 km, and pipe diameters of between 24’’ and 56’’, a gas pipeline can transport up to 6-7 MSm3/h, i.e. approximately 5500 MMscfd.
Note that beyond 48’’, pipelines must adhere to local legislation. Currently, only Russia permits pipeline diameters of 56’’.
Similarly, the maximum pressure in an onshore pipeline is limited by the country’s legislation. Generally, the maximum value is 80 bar. Exemptions have been granted up to 100 bar, following negotiations with the authorities.
© 2013 - IFP Training
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Gas pipeline: selection criteria
Advantages • • • • • •
Important orders of magnitude:
• Consumption of 1 % per 1000 km Mature • 1.5 to 2 kT CO2/MMBoe Relatively simple Efficient, and low CO2 emissions No restrictive specifications Economical for short distances Applicable to all types of reserves in principle
Drawbacks Location constraints highly case dependent Long-term fixed transport installation Sensitivity to geopolitical risk Not economical over long distances
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• • • •
22
LNG: the LNG chain
Liquefaction, transport and regasification • Train capacities: from 1 to 8 MTPA • Transport: atmospheric pressure and T=-160° °C • 1 m3 of LNG = 580 Sm3 of natural gas
© 2013 - IFP Training
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LNG: the LNG chain Comments on the previous slide
Liquefaction is a technology used for condensing natural gas, with a high volume reduction factor: 580 m3 of natural gas per m3 of LNG. The gas is transported in liquid form at atmospheric pressure and at a temperature close to - 160° °C. The quantities used by an LNG project are always large (> 3 3 MTPA, i.e. 4.5 billion m /year), and generally supply regasification terminals serving national distribution networks, except for Japan, where certain terminals only supply power stations.
An LNG transport chain comprises the following main stages: • • • • • • •
This mature technology has the following advantages: greater flexibility than pipelines, high efficiency. On the drawbacks side, it is highly capital-intensive, and requires long-term contracts.
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processing and transport by gas pipeline to the coast processing of produced gas to bring it up to the requisite specifications for liquefaction (deep sweetening, dehydration, removal of heavy metals…) liquefaction of gas, possibly accompanied by recovery of Liquefied Petroleum Gases (LPG) for separate end use storage and loading (shipping terminal) transport by methane tankers receival and storage regasification.
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LNG: liquefaction
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With 8 production trains, the plant has reached a capacity of 22.25 MT/year of LNG + 1 Mt/year of LPG + 10 Million b/year of condensates
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LNG: comparative transport costs 5
$/MMBtu
High-cost gas pipeline 4
Low-cost gas pipeline 3
LNG
2
1
Oil tankers
Oil pipeline km
Heavy investment: ($/mmbtu)
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160 0
320 0
400 0
Production: 0. – 2.5 Processing: 0.1 – 0.25 * 3 offshore Transport: 0.5 – 4.5 Distribution: 1.2 – 2.8 TOTAL: 2.1 – 10.5
640 0
800 0
© 2013 - IFP Training
80 0 Comments
26
LNG: selection criteria
Advantages • • • • •
Mature, except for offshore LNG (FLNG) Efficient for transport Economical over long distances Storage Flexible for downstream
Important orders of magnitude: CO2 spec of feed gas: CO2 < 50 ppm Liquefaction cons.: 10-15 % Transport cons.: 0.4 %/1000 km Regasification cons.: 0.5-1.5 % Liquefaction emissions: 35-45 CO2/MMboe • NG reserves : large • • • • •
kT
Drawbacks High investment required Tough location and installation constraints CO2 specifications High internal consumption and CO2 emissions Uneconomical over short distances Economical for large gas reserves
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• • • • • •
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CNG: principle
Pressure (bar.a)
m3 gas/m3 transported
Vapour
Liquid © 2013 - IFP Training
Temperature (°C) 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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CNG: principle Comments on the previous slide
This graph positions the various CNG technologies in pressure and temperature terms in relation to one another and to LNG. As a reminder, LNG - Liquefied Natural Gas - is a gas condensed at a temperature of – 160°C and at ambient pressure.
8 different CNG technologies - of varying maturity , as we will see later - are currently available on the market. They function in two fairly distinct pressure and temperature ranges. The first, qualified as High Pressure, is associated with ambient temperature, which gives operating pressures for CNG cylinders of approximately 200 to 250 b. The second is a medium pressure region (around 120/130 b) associated with a lower temperature of around –30°C.
The efficiency gain obtained by cooling the gas operates on 2 levels: The volume occupied by the gas is reduced as a function of the temperatures ratio (PV/T = cste)
•
At low temperatures, the behaviour of the gas increasingly diverges from the ideal gas law, the compressibility factor expressed in the formula (PV = nZRT) drops steeply, which results in a steep increase in the compression ratios. Conversely, employing low temperatures makes the whole export chain more complex
•
These combinations can achieve ratios of gas volume under standard conditions to volume transported of 230 to 290 m3/m3. This is to be compared with the ratio of 580/600 obtained for LNG.
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•
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CNG: principle
Gas transported in dense state: • either at ambient temperature and P = 250 bar • or T = – 30° °C and P = 120 bar CNG downstream process
CNG upstream process
CNG fleet
CNG export method
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Unloading system
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Loading system
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CNG: principle Comments on the previous slide
The principle of gas transport as CNG is based on obtaining a gas in dense phase state through compression at ambient temperature or low temperature (approx. – 30° °C). The fluid obtained 3 reaches densities of around 150 to 250 kg/m , as compared with 500 kg/m3 for LNG.
The gas is processed upstream in order to achieve the transport and, where relevant, commercial specifications and is then transported (by ship or truck) to the downstream processing site, where it will be transferred to a local market.
This technology seems to be a valid alternative to LNG and pipelines for certain cases (small quantities of gas and short distances) but, as at 2012, there are not yet any operational references for sea transport, although there are land transport references by truck in Argentina, for example.
© 2013 - IFP Training
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CNG: selection criteria
Advantages • No very restrictive specifications • Makes short distances economical • Offshore production
Important orders of magnitude • Km 0 consumption: 12% • Transport consumption: 1%/1000 km • Total emissions over 2000 km: 30 kT CO2/MMboe • NG reserves : low, average
Drawbacks • No commercial application with transport by ship in 2012 • Inefficient for transport • High costs © 2013 - IFP Training
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Transport in the form of hydrates (NGH): principle
After CNG, now let’s look at methane hydrates as a gas transport solution. With CNG, the gas is compressed to concentrate it; with liquefaction we turn it into a liquid through condensation; and with hydrates we turn it into a solid by trapping gas molecules in crystalline water structures. The diagram positions the hydrate formation region in pressure regions of around 40/50 bar and at positive temperatures. Then the hydrates are cooled and the pressure returned practically to ambient pressure. A metastability phenomenon revealed by the Norwegians enables hydrates to be kept stable for transportation. 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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Comments
33
Transport in the form of hydrates (NGH): principle
Gas transport in solid form: • at atmospheric pressure and T = – 20° °C
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Major drawback: transport of 85% water (by mass)
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Transport in the form of hydrates (NGH): principle Comments on the previous slide
Natural gas hydrates offer a means of storing large quantities of gas with a volume reduction factor of around 180 (less advantageous than LNG – 600 - and CNG – 300 on average). They are also stable under normal conditions. NGH consists in using gas hydrates to transport the gas in solid form at atmospheric pressure and at a temperature of approximately – 20° °C. It is defined by the following stages: •
Production: the gas from a field is injected into a reactor at a temperature of approx. 10° °C and a pressure of 60 bar where, in contact with water, it will be trapped in the form of hydrates.
•
Transport: the hydrates are transferred to a ship and transported from the production site to the distribution site.
•
Regasification: close to the distribution market, the hydrates are dissociated and the gas is distributed.
NGH is immature and does not seem to have great potential, in the short term at least.
© 2013 - IFP Training
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Transport in the form of hydrates (NGH): selection criteria
Advantages • Transport pressure
at
atmospheric
Drawbacks
Important orders of magnitude • Km 0 cons.: 4-5 % • Transport cons.: 3 %/1000 km • Total emissions over 3000 km: 50 kT CO2/MMBoe • NG reserves : very small
• Immature, industrial feasibility not proven. 2015-2020 deadline? • Transports 85% water (by mass) • Inefficient • High costs • Very low gas reserves © 2013 - IFP Training
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Gas to wire (GTW): principle
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Gas to wire (GTW): principle Comments on the previous slide
One of the solutions for transferring medium quantities of gas to the markets is to convert it into electricity. This technology, dubbed GTW (Gas to Wire), has numerous advantages: •
electricity is the energy source most easily usable by the consumer and also offers significant growth prospects
•
deregulation of the electricity market in many countries offers the opportunity to become a producer
•
using gas as a fuel makes GTW an ecologically clean sector
•
the cycles used are efficient compared to other means of electricity production.
GTW also has drawbacks: given the large quantities of electricity produced, you need a market able to provide outlets for it. In many potentially GTW candidate countries, the local market can only absorb a small proportion of the electricity produced. The rest must be transported over distances of thousands of km, which is costly, involves substantial losses and exposes the installations to sabotage.
•
a power station requires a stable supply chain over a period of at least 20 years. A gas production profile associated with oil production often peaks before rapidly falling. So GTW will be more suitable for natural gas deposits.
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•
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GTW: combined cycle power station
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GTW: combined cycle power station Comments on the previous slide
The combined cycle uses the heat from the gas turbine exhaust gases to generate steam, which expands in a turbine until it condenses. Hence the power of the gas turbine is increased by one third and the net overall ISO efficiency may reach 58%. The main parts in a combined cycle are the gas turbine, the recovery boiler, the steam turbine, the condenser and electricity generator.
The condenser uses ambient air or water to condense the steam; the choice of condenser type depends on the local water resource, and directly influences the combined cycle performance.
A combined cycle brings numerous advantages: • • •
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• • • • •
high efficiency, i.e. electricity production at minimum costs partial-load operation can be optimised by adjusting the power station configuration (3*33 % or 2*50 %) high availability (92% on average over a year) if the maintenance program, concentrated within the offpeak period, is observed flexibility of use, especially with the Single-shaft configuration small workforce (54 people for a 1260-MW power station) investment cost lower than for a steam power station short construction time (25 months for a standard module) lower atmospheric emissions
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Gas to wire (GTW): efficiency
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Gas to wire (GTW): efficiency Comments on the previous slide Continuous transport of electrical energy
DC (direct current) transport has numerous advantages over AC (alternating current) transport: • • • • •
lower line installation cost smaller line losses possible interconnection of networks operating at different frequencies continuity of service in case of failure highly flexible operation
Conversely, the major drawback of DC transport is the obligation to install at each line-end an AC/DC conversion station, which is expensive (approx. $175 million (in 2000) for 1000 MW in +/500 kV). However, beyond a certain transport distance, the savings generated by the lower installation cost of a DC line compensate for the expense of building conversion stations. © 2013 - IFP Training
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GTW: combined cycle organisation BangBo - ABB/Alsthom technology • • • • •
Cooling tower Water treatment Discharge water Heat recovery steam generator Gas compressor
• • • • •
Gas inlet Fuel storage Clean water tank HV zone Turbine buildings
© 2013 - IFP Training
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Gas to wire (GTW): selection criteria
Advantages Mature technology Attractive thermal efficiency and costs Open electricity market Rapid implementation (construction 2 years) • Operating flexibility • No special constraints • • • •
Important orders of magnitude • 1 MSm3/d gas = 250 MWe (combined cycle) • Electricity generation efficiency (combined cycle): ~ 50 % • NG reserves : small
Drawbacks
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• Economical for capacities < 1000 MW • Not economical over long distances (> 1500-2000 km) • Very high surface area of AC/DC and DC/AC conversion stations
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Contents
Gas chain
Transport routes
Chemical conversion routes • Fischer-Tropsch (GTL/FT) • DiMethyl-Ether (DME) • Methanol and other chemical sectors
Positioning and processing requirements for each monetization route
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Chemical conversions
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Chemical conversions Comments on the previous slide
Another way of commercialising natural gas is to chemically convert it into liquid products, more easily transportable under ambient conditions. There are various methods, but the first stage common to every case is conversion of natural gas into synthesis gas with catalysts (SMR, ATR, catalytic POx) or without catalysts (gas POx), a mixture of carbon monoxide (CO) and hydrogen (H2). The H2/CO ratio of the synthesis gas produced must differ according to the target end product.
The products examined in this study are: • • •
the Fischer-Tropsch process, producing Diesel and naphtha methanol DME: only the direct process is examined here, as it maximises energy efficiency
These differ widely in terms of target markets and their size. The technical constraints (process, location, etc.) vary.
For information, the optimum stoichiometric ratios at the synthesis gas production outlet are as follows: GTL/FT: H2/CO = 1.7 for iron-based catalysts and H2/CO = 2 for cobalt-based catalysts Direct DME: H2/CO = 1 Methanol H2-CO2 / CO + CO2 = 2
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• • •
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GTL/FT: brief history
1920
1940 1924
German discovery Conversion of CO & H2 into hydrocarbon
F.Fischer & H.Tropsch
1935
WWII
1960 1955
1980 1980-82
2000 1990-2000
2006 2007
1993 1st Industrial FT Atmospheric fixed bed reactor - Rhurchemie
SASOL I Iron Medium Pressure Synthesis commercialized by Rhurchemie and Lurgi (8,000 BPD)
9 FT Plants built in Germany Support German petroleum independency during WWII (~16,000BPD)
SASOL II & III 150,000 BPD plant in South Africa, Fe catalyst and Circulating Fluidized Bed Reactor
ORYX (QP+SASOLChevron) 34,000 BPD plant in Qatar Co Cat. Slurry Reactors.
Synthol CFB Reactors
WWII German Low Pressure Reactors
ARGE Fixed Bed Reactor
SHELL BINTULU 12,500 BPD plant in Malaysia, Co catalyst Fixed Bed Reactor
PEARL (QP+SHELL) 2x70,000 BPD plant in Qatar - Co Cat. Fixed bed Reactors.
© 2013 - IFP Training
Patent granted to Fischer & Tropsch
SASOL Dev. of “Advanced Synthol Process” SASOL II & III Reactors Replacement
Source: Total 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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GTL/FT: principle
Production of liquid hydrocarbons from natural gas in 3 stages: • Synthesis gas generation - highly endothermic • Fischer-Tropsch synthesis - highly exothermic • upgrading Light HC (used as fuel H2O and/or O2
Fields
Pretreatment
Synthesis gas generation
Steam
FischerTropsch synthesis
gas or syngas load)
Waxes and
Hydro-treatment condensates Hydro-cracking
Water
(+ lube bases)
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Local or transport
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Diesel + Paraffin naphtha
MARKETS: Local or transport Petrochemicals
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GTL/FT: principle Comments on the previous slide
Chemical conversion of natural gas via Fischer Tropsch synthesis, often known as GTL/FT, produces liquid hydrocarbons such as gas oil or kerosene. It follows the three main stages below: •
conversion into synthesis gas (“syngas”), a mix of carbon monoxide and hydrogen
•
Fischer Tropsch synthesis: primarily paraffin-like, very long carbon chain compounds, known as waxes
•
upgrading into lighter hydrocarbons by means of hydro-treatment units, to obtain primarily diesel (75%) and naphtha (25 %).
A successful GTL chain necessarily means integrating the three units, and this demands highly specialised know-how.
This highly capital-intensive technology has few operational references, low efficiency and high CO2 emissions, but it opens up access to the huge fuels market.
© 2013 - IFP Training
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GTL/FT: synthesis gas generation
1.
SMR
Boiler zone
S/C > 2.5 T: 850-900°C P ~ 20 bar H2/CO ~ 4.8 flue gas
Prerefor mer
Radiant zone (naked flames / tubes filled with catalyst)
steam Desulphurised natural gas (ppb’s S)
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air
synthesis gas to process
fuel gas 51
GTL/FT: synthesis gas generation
2.
POX
S/C < 0.2 T ~ 1350°C P ~ 60 bar H2/CO <1.9 Advantages:
Constraints:
High conversion High CO/CO2 selectivity H2/CO ratio close to optimum for F-T Need for additional SMR High outlet T Air separation plant
© 2013 - IFP Training
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GTL/FT: synthesis gas generation
3.
ATR S/C ~ 1.2 T ~ 1050°C P ~ 20-50 bar H2/CO ~2.6
Combining POX and catalytic reforming
Constraints:
CO2 recycling, F-T purge Air separation plant
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N.B. there is air ATR, with constraints downstream due to high nitrogen load
53
GTL/FT: the Fischer-Tropsch stage Main reaction
n CO + 2n H2 -(CH2)n- + nH2O + n x 165 kJ
primarily: mix of paraffins C1->C200 olefins alcohols, acids, oxygenated solvents volume water ~ volume HC no sulphur or aromatics
Catalyst: iron based or cobalt based Reactor: multi-tube fixed bed or “slurry” 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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Technological options
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GTL/FT: selection criteria
Advantages • Usable over a wide range of capacities • Efficient to transport • No market constraint
Important orders of magnitude • • • •
H2S < 0.1 ppm Energy efficiency: 42-52% Emissions: 150 kT CO2/Mmboe NG reserves : average to large
Drawbacks
Oryx Sasol /QP: 34,000 bpd 20444_a_A_ppt_07 - END USES OF NATURAL GAS
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• H2S specifications • High energy consumption and high CO2 emissions • High technical cost (compared to other types of conversion) • Complexity due to various types of product
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DME: principle
Two processes:
Pilot Plant in JFE Tsurumi Factory
• direct conversion or via methanol
Two different markets: • chemicals ( olefins) and energy (fuel for vehicles)
© 2013 - IFP Training
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DME: principle Comments on the previous slide
Today’s global DiMethylEther (DME) market represents 150,000 tonnes per year, and encompasses aerosol applications, particularly in the field of cosmetics. Since this application is already mature and the market very small, DME could be used as diesel fuel in appropriate engines (clean gas fuel), as fuel in energy production turbines or in domestic applications. With the chemical formula CH3O-CH3, DME is gaseous under normal conditions and its physical characteristics are very similar to those of LPG.
There are two types of process for synthesising DME, either directly, or via methanol as the intermediary.
The direct process optimises energy efficiency: the potential maximum efficiency (65-70%) appears to be the best of the conversion processes.
There are a host of technology licensors for the indirect process: TOPSOE, LURGI, TEC and MGC. At present, only JFE fully masters the direct process. © 2013 - IFP Training
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DME: selection criteria
Advantages • Lower CO2 emissions than GTL/FT • Single product • Possibility of mixing with LPG
Important orders of magnitude • • • •
H2S < 0.1 ppm Energy efficiency: 60% Emissions: 75 kT CO2/MMboe NG reserves : small
DME is supplied from 100t/d Demonstration Plant at Kushiro
Drawbacks
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• H2S specifications • Immature: no commercial installation in 2011 (one in project) • Markets to be developed
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Methanol: principle
3 stages: • Synthesis gas generation • Methanol synthesis • Distillation
© 2013 - IFP Training
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Methanol: principle Comments on the previous slide
Methanol is the simplest alcohol, with chemical composition CH3-OH, and is used primarily as a base compound in the chemicals industry. Methanol fuel is very little used at present. The main outlet today (approx. ¾ of worldwide production) is in the manufacture of chemicals, primarily formaldehyde. Then comes manufacture of MTBE (approx. 1/4 of the market), an additive added to petrol to increase its octane rating. It is synthesised in three stages, as in the case of Fischer Tropsch synthesis: • • •
synthesis gas production methanol synthesis purification of end product
For the moment the methanol route is essentially limited by the market size.
The first cases of a methanol production rate exceeding 1000 t/d date back to the 1980s. The plants are located chiefly in gas-producing countries. © 2013 - IFP Training
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From gas to plastics: principle
4 stages: • • • •
synthesis gas generation methanol or DME synthesis conversion into olefins (MTO / DTO) polymerisation Integrated MTO - PE-PP
Natural gas Coal
Methanol Plant MTO
Syngas Plant
indirect
direct
DME Plant
+ OCP Plant
Polyethylene Plant Polypropylene Plant
Source: Total Petrochemicals
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MTO: Methanol to Olefins DTO: Dimethylether to Olefins OCP: Olefin Cracking Process
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Methanol: selection criteria
Advantages
• Mature • More efficient and lower CO2 emissions than GTL/FT • The cheapest of the conversion routes • Single product
Important orders of magnitude • • • •
H2S < 0.1 ppm Energy efficiency: 65% Emissions: 75 kT CO2/Mmboe NG reserves : small
Drawbacks
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• H2S specifications • Market constraint: economy of scale required, but difficult due to the tight market
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Contents
The gas chain
Transport
Chemical conversion
Positioning and processing requirements for each monetization route © 2013 - IFP Training
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Positioning for each monetization route Reserves
10 TCF
5 TCF
0
GAS PIPELINE LNG CNG DME MeOH Distances to 500 market
GTL 1000
10 000 km
GAS PIPELINE LNG CNG GTL / MeOH / DME: distance to market: no real impact Energy Eff.
50 %
60 %
70 %
90 %
80 % LNG CNG
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MeOH
DME
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GAS PIPELINE
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Positioning for each monetization route Comments on the previous slide
Gas pipelines transport medium-to-high volumes of gas over distances of thousands of km. They remain a rigid solution, sensitive to geopolitical risks. They are also limited by geographical constraints (e.g. ocean trenches).
To transport gas over very long distances, LNG is the most economical solution but as it is expensive, the economy requires high volumes of gas.
CNG is more suitable for small volumes of gas and short distances (up to 1,000 km).
The conversion processes all have lower energy efficiencies than the transport alternatives. The market for the Fischer-Tropsch method products is not limited, unlike the DME and methanol method markets which are very limited.
© 2013 - IFP Training
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Commercial specifications of gas
Interchangeability: measured by Wobbe index 3 categories of countries for gases: Specific gravity of methane = 0.555
IW =
PCS dgaz dair
Asian Countries RICH GASES
Specific gravity for black flue gas = 0.7
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United States and United Kingdom: LEAN GASES
European countries: future EASEE-gas standard
© 2013 - IFP Training
Nitrogen
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Commercial specifications of gas Comments on the previous slide
There are several kinds of commercial specifications: • • •
toxicity and corrosion (max. content of oxygen and sulphur-based compounds) formation of hydrates and liquid (water and hydrocarbons dew point) interchangeability
Interchangeability characterises the composition thresholds and properties of the gases, to ensure satisfactory operation of devices running on gas, and is measured by the Wobbe index. It is important this should remain as constant as possible. We therefore give an upper and lower threshold value for this index, and combustion emissions can be controlled, burner efficiency is improved and the operating conditions of this equipment are secured.
This positioning enables us to determine the type of composition possible for an H type gas (high heating value): so lean gases will contain little C3+ and may have relatively large proportions of nitrogen. Gases for Japan, on the other hand, must be low in N2 and rich in ethane and propane.
Certain gases, known as L gases (low heating value), contain more inert gas and have Wobbe index values below 47 MJ/Nm3, and so are not interchangeable with any current specifications. This is the case for certain fields in Thailand and the Groningen gas reserves in the Netherlands, for example. So with very little or no pre-treatment, these gases must be distributed in a different network.
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Technological specifications
3 families of routes for the H2S/CO2 grid 4 3
2 H2S, total S or H2S+COS specifications
1
0
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EASEE-gas: H2S+COS < 3 ppm and total sulphur < 19 ppm L gas: CO2 spec at 25% mol for the Thai network for example
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Technological specifications Comments on the previous slide
It is important to stress that the EASEE-gas H2S specification is more precisely a specification limiting H2S + COS to 3 ppm.
Gas monetization routes fall into three categories: •
LNG, for which the constraints are both technological (CO2 which must be removed to prevent it from crystallising and clogging the equipment in cryogenic zones) and commercial
•
the conversion routes, where there is no reason for commercial gas specifications, leaving only H2S content, which is highly restrictive (H2S is poisonous to the catalysts used, even at low concentration)
•
gas pipelines, CNG and methane hydrates: only commercial specifications (H2S, CO2) are genuinely restrictive.
© 2013 - IFP Training
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Quiz True The gas chain includes a gas treatment stage, followed by transport to the consumer markets.
False
●
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………….…..
It also includes a gas conditioning stage (compression, liquefaction) for ‘transport’ to the energy gas markets, or a chemical conversion stage for conversion before the transport stage.
All technologies involving chemical conversion of the gas start with a synthesis gas generation stage
●
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… Yes. The synthesis gas is then converted into liquid hydrocarbons (GTL-FT), methanol or DME. …………………………………………………….…..
LNG is more economic than gas pipeline transport over distances of more than 3,000 km.
●
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… True, insofar as it is possible to transport the gas by sea; otherwise land transport of large quantities of LNG is impossible. …………………………………………………………………………………………………………………………………………….…..
All gas liquefaction plants are located on the coast
●
………………..…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… ………………………………………………………………….….. Liquefied gas is effectively transported over long distances in methane tankers. If the gas deposit is far from the coast, it is preferable
to transport gas in a pipeline as far as the coast, and liquefy it at the methane tanker loading site.
Conversion of gas into DME has good energy efficiency, better than GTL-FT and equivalent to that of LNG
●
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… ……………………………………………………………….…..……..
DME is more energy-efficient than GTL-FT (70% vs. 60%), but less efficient than LNG (80-85% efficiency)
CNG can be used to exploit very large gas reserves (more than 5 Tcf), but over relatively short distances (< 1000 km)
●
……..
CNG is denser than LNG ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… …………………………………………………………………….….. False. The specific gravity of LNG is 580 times denser than gas under standard conditions; the specific gravity of CNG is between 295 ..and
320 times that of gas under standard conditions, depending on the CNG process used.
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●
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……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… No, CNG is suitable for medium-sized gas reserves (less than 2 Tcf), over relatively short distances. ……………………………………………………………….…..
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Key points to remember The gas chain comprises several stages: production and processing, conditioning or chemical conversion, and transport to the consumer markets.
The gas markets are generally a long distance away from the production sites.
Gas may be transported by means of a gas pipeline (gaseous at ambient temperature and at high pressure), by methane tankers (liquid at – 160°C and atmospheric pressure) or under intermediate conditions (CNG).
Chemical conversion enables us to reach the fuel oils and lubricants markets (GTL/FT, DME) or the chemicals market, while facilitating transport – but at the cost of major investment.
The monetization route must be selected on an individual basis, according to the markets available and the economy of each route (dependent on the size of the reserves, the product value and the transport cost).
Gas processing must be suited to the monetization route, so as to satisfy the commercial specifications of the finished product, but also the technological specifications specific to each route.
20444_a_A_ppt_07 - END USES OF NATURAL GAS
© 2013 - IFP Training
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Approximate conversion factors
Chaleur / Energie Heat / Energy Million Btu (MMBtu)
GJ 1
Mcal 250
kWh 300
Flow rate Débit
Volume cubic meter (cm)
Heating Value Valeur Calorifique Btu/cf 1000
cubic feet (cf) 35
Mcal/m3 9
Million cubic feet per day (MMcfd) 100
Btu/m3 35 000
Mj/m3 35
Billion cubic meter per year (Bcm/y) 1
kWh/m3 10
Equivalences 1 bep 1 t1charbon t coal
t (LNG) t (GNL)
20444_a_A_ppt_07 - END USES OF NATURAL GAS
m3m3 (LNG) (GNL) 2,5
m3 (gas) m3 (gaz) 1500
MMBtu 53
kWh 15 000
m3 m3(gas) gaz 180 750 © 2013 - IFP Training
Gaz naturel liquéfié Liquefied natural gas
MMBtu gaz 6 25
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