Unit-10 Methanol To Olefin

PROCESS FOR CONVERSION OF METHANOL TO OLEFINS (MTO)

CH3OH

>C=C< Dr. R. P. Badoni Distinguished professor

Process Licensors • UOP • Norsk Hydro ,Oslo Norway (100% Conversion in Half ton Methanol per day plant).

MANUFACTURE • Changing Natural gas To Olefins Is a Two Step Process : Natural gas Methanol

Methanol Olefins (UOP/HYDRO)

• UOP/HYDRO MTO Process primarily converts the methanol into ethylene and propylene. • Other technologies for indirect conversion of methane to higher value products do exist. These process have lower yields, less economical compared to UOP/HYDRO MTO Process. • The UOP/HYDRO MTO Process provides an

• Exceptional UOP HYDRO value for direct conversion

PROCESS of methane to polymer grade ethylene and propylene. • Direct use of ethylene and propylene in chemical grade products with greater than 98% purity using a flow scheme that

does

not

ethylene/ethane

require or

expensive

propylene/propane

splitters. • Limited

production

of

by-products

compared to a steam cracker, which results in a simplified product recovery

UOP/HYDRO MTO PROCESS OFFERS

• Easy integration in to existing naphtha cracker facilities due to low paraffin yields. • Flexibility to change the ethylene to propylene product weight ratio from 1.5 to 0.75. • It

also

has

significantly

lower

environmental emissions, such as NOX and

Chemical reaction • Dehydration with shape selective transformation to low molecular weight alkanes. • Methanol SAPO-34[AlPO4] Molecular Propylene EthyleneCatalyst Seive Butylenes

MTO FLUIDIZED-BED REACTOR AND REGENERATOR SECTION Heat Recovery

Flue GAS

To Compression & Product Recovery Section

Air

Crude Methanol

REACTO R

REGENERATO R

Heat Recover y Wat er

Vaporization & Preheating

MTO PROCESS RECOVERY SECTION

Feed from Reaction

C3 Splitter

Debutanizer

Compressi on

ORU unit

Drying Depropaniz er

Co2 Removal

Acetylene Saturation

C2

C2 Splitter

Deethanis er

Compressio n

Demethani zer

C1

C3 C4

& Regeneration Section

C5+

FEEDSTOCK S • Feedstock

for

the

UOP/HYDRO

MTO

process is crude, non-distilled methanol usually produced from synthesis gas, which is produced from the reforming of abundant natural gas. • Synthesis gas can also be produced by steam reforming of petroleum products such as naphtha, partial oxidation of natural gas and petroleum products, and coal gasification.

CATALYST • The reaction is catalyzed by the MTO100 silicoaluminophosphate synthetic molecular sieve based catalyst. • The catalyst has demonstrated the degree of attrition resistance and stability required to handle multiple regenerations and fluidized bed conditions over the long term. • The catalyst is extremely selective towards the production of ethylene and propylene.

Catalyst • Zeolite consists of framework built of Tetrahedra • Each tetrahedra comprises a Tatom bound to Four oxygen atom. • Oxygen bridges connect the tetrahedra. • T- atoms are Si or Al.

Silica Alumina Framework O O

O

T O

•Crystalline micro porous (Pore Dia- 3-14 Anstron. •Framework density greater than 20 T atoms / 1000 Anstron.

Range of pore Sizes of Molecular Dimension • • • •

Small – 8 Ring - ~ 4 A’ Medium – 10 Rings - ~ 5-6 A’ Large - 12 rings - ~ 6-8 A’ Very Large - > 12 Rings - ~ 8 A’

TYPICAL MTO OPERATING CONDITIONS REACTOR

REGENERATOR

TEMPERATURE (0C)

350-530

600-720

PRESSURE (atm)

1-2

1-2

Operating Mode

Vapor Phase,

Vapor phase

Fluidized bed

Fluidized bed

Byproducts of the Process • • • • •

Water and Hydrogen Carbon Monoxide and Carbon Dioxide. Methane to C5 Paraffins C5+ Coke

Component

Ethylene

Maximum Ethylene Mode 48%

Maximum Propylene Mode 34%

Propylene

31%

45%

Butenes

9%

12%

C2=/C3=

1.5

0.75

APPLICATIONS 1. This process can be utilized in locations with cheap, abundant natural gas reserves. 2. By integrating UOP/HYDR MTO process in to gas to olefins (GTO) complex, feedstock prices can be held down and natural gas can be converted in to a form that is more easily transported and of higher value. 3. Existing naphtha or ethane-propane cracker facilities can increase olefin production and feedstock flexibility by installing an MTO reactor section and feeding in to a revamped cracker fractionation section to minimize the capital investment 4. Downstream of an existing methanol plant with excess capacity , to meet local demands for olefins and

Areas for Research – Modelling of MTO process in a circulating Fluidized bed reactor • The simulation combined with kinetic model with SAPO-34 as catalyst and the core annulus type hydrodynamic model. • Modelling studies may indicate ethylene selectivity vs increase in coke deposition on the catalyst “Cage Effect,” Methanol conversion vs coke deposit. • Optimum % of coke deposit vs

Simulation • The influence of the exit geometry such as smooth exit, abrupts exist & exits with a projected end on solid hold up and thereby on methanol conversion. • Simulator prediction of the flow characteristics within CFB.