Basics Compressor Calculation
This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA
Overview
Download & View Basics Compressor Calculation as PDF for free.
More details
- Words: 734
- Pages: 12
Loading documents preview...
Basics Compressor Calculation
Sven-Olaf Zillmann Project Manager Sales Head of Team Pipeline Process Industry
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
1
>
Basics Compressor Calculation For the calculation of a compressor two steps are necessary: 1. Thermodynamic calculation 2. Mechanical calculation
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
2
>
Basics Compressor Calculation Thermodynamic calculation
The compressor is a volumetric machine due to the geometry of the impeller
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
3
>
Basics Compressor Calculation Thermodynamic calculation Step 1: get the usual process data The needed data are: Volume (mass) flow, inlet & outlet pressure, inlet temperature, molecular weight (gas composition)
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
4
>
Basics Compressor Calculation Thermodynamic calculation
Step 2: Calculate the polytrophic head for the design point
h = R * z1 * T1 * n / (n – 1) * [(p2/p1)(n-1)/n - 1 ] h = polytrophic head
[ kJ / kg ]
p1 = suction pressure at compressor flange
[bar a]
p2 = discharge pressure at compressor flange [bar a] T1 = suction temperature at compressor flange [K] z1 = compressibility at suction condition
typical value z1 = 0,92
R = gas constant = 8.315 / MW [kJ/kg K] MW = molecular weight n = polytropic exponent MAN Diesel & Turbo SE
typical value n = 1.4 Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
5
>
Basics Compressor Calculation Thermodynamic calculation
Step 3: calculate the gas power
P=m*h/η P = gas power
[kW]
m = mass flow delivered to the process [kg/s] h = polytropic head [kJ/kg] η = average polytropic efficiency (eta)
typical value η = 0,84
The massflow can be calculated from the volume flow pressure unit is bara, temperature unit is Kelvin, diameter unit is meter
Radial and axial bearing losses: typically 50 - 80 kW
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
6
>
Basics Compressor Calculation Thermodynamic calculation
Step 4: calculate the number of impeller
Nimp = h / (μy * u22) Nimp = Number of impeller h = Head needed at design point [ J/kg ]
μy = head coefficient, typical value 0.48 to 0.54 u2 = peripheral speed
[ m/s ]
typical value = 250 to 280 m/s
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
7
>
Basics Compressor Calculation Mechanical calculation
Two mechanical calculation has to be done: 1. Lateral analysis To find out the lateral eigenfrequencies of the compressor. The excitation comes from the gas dynamic and the mass distribution on the shaft. 2. Torsional analysis To find out the torsional eigenfrequencies of the whole train. The excitation comes from the driver e.g. motor or gas turbine. A motor with a frequency converter is more complicated than a gas turbine.
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
8
>
Basics Compressor Calculation Mechanical calculation The lateral analysis must be done to ensure the stability of the compressor. The analysis shows if the compressor runs in or near the natural eigenfrequencies (lateral critical speed).
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
9
>
Basics Compressor Calculation Mechanical calculation
The torsional analysis must be done to ensure the stability of the whole train. This includes the compressor, gear (if necessary) and the driver. Especially if a VFD motor is the driver of the train. A VFD creates an excitation by running in part load. This is typically for an VFD.
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
10
>
Disclaimer All data provided in this document is non-binding. This data serves informational purposes only and is especially not guaranteed in any way. Depending on the subsequent specific individual projects, the relevant data may be subject to changes and will be assessed and determined individually for each project. This will depend on the particular characteristics of each individual project, especially specific site and operational conditions.
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
11
>
Do you have any more questions?
Sven-Olaf Zillmann [[email protected]]
MAN Diesel & Turbo SE
Benjamin Omlor [[email protected]]
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
12
>
Sven-Olaf Zillmann Project Manager Sales Head of Team Pipeline Process Industry
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
1
>
Basics Compressor Calculation For the calculation of a compressor two steps are necessary: 1. Thermodynamic calculation 2. Mechanical calculation
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
2
>
Basics Compressor Calculation Thermodynamic calculation
The compressor is a volumetric machine due to the geometry of the impeller
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
3
>
Basics Compressor Calculation Thermodynamic calculation Step 1: get the usual process data The needed data are: Volume (mass) flow, inlet & outlet pressure, inlet temperature, molecular weight (gas composition)
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
4
>
Basics Compressor Calculation Thermodynamic calculation
Step 2: Calculate the polytrophic head for the design point
h = R * z1 * T1 * n / (n – 1) * [(p2/p1)(n-1)/n - 1 ] h = polytrophic head
[ kJ / kg ]
p1 = suction pressure at compressor flange
[bar a]
p2 = discharge pressure at compressor flange [bar a] T1 = suction temperature at compressor flange [K] z1 = compressibility at suction condition
typical value z1 = 0,92
R = gas constant = 8.315 / MW [kJ/kg K] MW = molecular weight n = polytropic exponent MAN Diesel & Turbo SE
typical value n = 1.4 Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
5
>
Basics Compressor Calculation Thermodynamic calculation
Step 3: calculate the gas power
P=m*h/η P = gas power
[kW]
m = mass flow delivered to the process [kg/s] h = polytropic head [kJ/kg] η = average polytropic efficiency (eta)
typical value η = 0,84
The massflow can be calculated from the volume flow pressure unit is bara, temperature unit is Kelvin, diameter unit is meter
Radial and axial bearing losses: typically 50 - 80 kW
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
6
>
Basics Compressor Calculation Thermodynamic calculation
Step 4: calculate the number of impeller
Nimp = h / (μy * u22) Nimp = Number of impeller h = Head needed at design point [ J/kg ]
μy = head coefficient, typical value 0.48 to 0.54 u2 = peripheral speed
[ m/s ]
typical value = 250 to 280 m/s
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
7
>
Basics Compressor Calculation Mechanical calculation
Two mechanical calculation has to be done: 1. Lateral analysis To find out the lateral eigenfrequencies of the compressor. The excitation comes from the gas dynamic and the mass distribution on the shaft. 2. Torsional analysis To find out the torsional eigenfrequencies of the whole train. The excitation comes from the driver e.g. motor or gas turbine. A motor with a frequency converter is more complicated than a gas turbine.
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
8
>
Basics Compressor Calculation Mechanical calculation The lateral analysis must be done to ensure the stability of the compressor. The analysis shows if the compressor runs in or near the natural eigenfrequencies (lateral critical speed).
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
9
>
Basics Compressor Calculation Mechanical calculation
The torsional analysis must be done to ensure the stability of the whole train. This includes the compressor, gear (if necessary) and the driver. Especially if a VFD motor is the driver of the train. A VFD creates an excitation by running in part load. This is typically for an VFD.
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
10
>
Disclaimer All data provided in this document is non-binding. This data serves informational purposes only and is especially not guaranteed in any way. Depending on the subsequent specific individual projects, the relevant data may be subject to changes and will be assessed and determined individually for each project. This will depend on the particular characteristics of each individual project, especially specific site and operational conditions.
MAN Diesel & Turbo SE
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
11
>
Do you have any more questions?
Sven-Olaf Zillmann [[email protected]]
MAN Diesel & Turbo SE
Benjamin Omlor [[email protected]]
Sven-Olaf Zillmann
Basics Calculation Compressor
nopq
18.11.2013
<
12
>
Related Documents
Basics Compressor Calculation
March 2021 0
Basics Of Compressor
February 2021 0
Compressor Sizing And Calculation
March 2021 0
Centrifugal Compressor Basics
January 2021 2
5- Basics Of Fault Calculation
January 2021 0
Compressor
February 2021 2More Documents from "Paras Palsatkar"