Multi-Stage Cascade Refrigeration System

Transcription

1 Multi-Stage Cascade Refrigeration System

2 Contents Refrigeration Cycle and Input Condition of Natural Gas Cascade Refrigeration Three-Stage Refrigeration of methane Two-Stage Refrigeration of ethylene Three-Stage Refrigeration of propane Multi-Stage Cascade Refrigeration Cycle & Results 02/33

3 Refrigeration Cycle and Input Condition of Natural Gas 03/33

4 What is the refrigerator? Ø y letting-down the pressure of chilled and highly compressed refrigerant, we can obtain a cold temperature of refrigerant. y adjusting the pressure letting-down level, we can obtain a wanted temperature level of refrigerant. Ø y cooling after compressing a vapor stream, we can obtain a liquefied refrigerant. 04/33

5 Ideal refrigeration Cycle Compressor Condenser P C D T T D D P, P D Evaporator T =T C P, P C C Expansion Valve H evap Process Flow Diagram Pressure Enthalpy Diagram H y utilizing the Pressure-Enthalpy (P-H) diagram, the refrigeration cycle can be broken down into four distinct steps : C D Expansion Evaporation Compression Condensation 05/33

6 Input Condition of Natural Gas Contents Value Pressure (bar) 53 Temperature ( o C) 45 Flow Rate (kg/hr) 625,000 Component Mole% Nitrogen 0.22 Methane Ethane 5.36 Propane 2.14 I-utane 0.46 N-utane 0.47 I-Pentane 0.01 N-Pentane 0.01 Total /33

7 Cascade Refrigeration 07/33

8 Cascade Refrigeration E01 Pressure drop(hot Side) : 0.5bar Minimum of [Hot Out-Cold In] and [Hot In-Cold Out] : 3 o C Refrigerant Component : C3 Refrigerant Temp. : o C E04 Pressure drop(hot Side) : 0.5bar Minimum of [Hot Out-Cold In] and [Hot In-Cold Out] : 3 o C Refrigerant Component : C2 - Refrigerant Temp. : o C E06 Pressure drop(hot Side) : 0.5bar Minimum of [Hot Out-Cold In] and [Hot In-Cold Out] : 3 o C Refrigerant Component : C1 Refrigerant Temp. : o C E02 Pressure drop(hot Side) : 0.5bar Minimum of [Hot Out-Cold In] and [Hot In-Cold Out] : 3 o C Refrigerant Component : C3 Refrigerant Temp. : o C E05 Pressure drop(hot Side) : 0.5bar Hot Product Temp. : -92 o C Refrigerant Component : C2 - Refrigerant Temp. : -95 o C E07 Pressure drop(hot Side) : 0.5bar Minimum of [Hot Out-Cold In] and [Hot In-Cold Out] : 3 o C Refrigerant Component : C1 Refrigerant Temp. : o C E01 E02 E03 E04 E05 E06 E07 E08 CV01 F01 Stream01 Pressure : 53bar Temperature : 45 o C Flow Rate : 625,000 kg/hr E03 Pressure drop(hot Side) : 0.5bar Hot Product Temp. : -37 o C Refrigerant Component : C3 Refrigerant Temp. : -40 o C E08 Pressure drop(hot Side) : 0.5bar Hot Product Temp. : -152 o C Refrigerant Component : C1 Refrigerant Temp. : -155 o C CV01 Pressure Drop : 0 F01 diabatic : duty 0 12 CN01 08/33

9 CN1 Condition & Result Rate of LNG Liquefaction =Stream12 Total Rate/Stream01 Total Rate X 100 = / X 100 = 91.71% 09/33

10 Cascade Heating Curve 50 0 [1] ) [2] -50 [3] [4] -100 [5] Temperature( -150 [6] C2 - [7] C3 [8] C Heat duty(10 6 Kcal/hr) 10/33

11 Cascade Heating Curve Temperature ( ) Heat duty (*10 6 Kcal/hr) Flowrate of refrigerator (kg/hr) [1] [2] [3] [4] [5] [6] [7] [8] Total /33

12 Multi-Stage Cascade Refrigeration Cycle Propane K08 M08 K07 M07 K06 M E12 62 V CV07 CV08 CV09 64L 62 F07 F08 F09 SP05 62L V 65 SP L 66 V SP K05 Ethylene M05 K04 M E01 E02 E03 03 E V 44 V 41 E11 42 CV05 F L SP CV06 F06 44L SP04 44 Methane E04 E05 K03 M03 31 K02 M02 29 K01 28 M E09 CV V CV V 25 24L 24 CV V 27 F02 F03 F04 22L 22 SP01 SP L E06 E07 E CV01 F /33

13 Three-Stage Refrigeration of methane 13/33

14 Three-Stage Refrigeration System Second Stage Discharge Pressure(K02) = Second Suction Pressure * Ratio per stage = * = bar First Stage Discharge Pressure(K01) = First Suction Pressure * Ratio per stage = * = bar Ratio per stage K03 32 M03 K02 30 M02 K01 M E09 22 V 24 V 26 V CV02 CV03 CV04 F02 F03 F04 22 L SP L SP L E06 E07 E08 Temperature of Refrigerator(E06) = Dew point temperature of propane at bar = o C Temperature of Refrigerator(E07) = Dew point temperature of propane at bar = o C 14/33

15 Calculation of total flowrate of methane CV02 Outlet Pressure : bar CV03 Outlet Pressure : bar CV04 Outlet Pressure : bar 15/33

16 CN1 Condition & Result Total Flowrate of methane Kgmol/hr = kg/hr 16/33

17 Three-Stage Refrigeration Cycle K03 Outlet Pressure : bar diabatic Efficiency : 70% K02 Outlet Pressure : bar diabatic Efficiency : 70% K01 Outlet Pressure : bar diabatic Efficiency : 70% E09 Pressure drop(hot Side) : 0.5bar Hot Product Liquid Fraction : 1 CV02 Outlet Pressure : bar CV03 Outlet Pressure : bar CV04 Outlet Pressure : bar F02/F03/F04 diabatic : duty 0 Stream21 Temperature : -92 ubble Point Component : Methane Total Fluid Flowrate : kg/hr E06/E07/E08 Pressure drop(hot Side) : 0.5 bar Cold Product Liquid Fraction : 0 17/33

18 Two-Stage Refrigeration of ethylene 18/33

19 Two-Stage Refrigeration System First Stage Discharge Pressure(K04) = Suction Pressure * Ratio per stage = * = bar Ratio per stage 50 K05 49 M05 K04 M E10 51 E11 42 V V 45 Condenser Heat Duty of C1 Refrigeration Cycle(E09) = *10 6 Kcal/hr 41 CV05 42 F05 CV06 F Temperature of Refrigerator(E04) = Dew point temperature of propane at bar = o C 42 L SP L SP04 44 E E04 E05 19/33

20 Calculation of total flowrate of ethylene Stream Name Temperature ( ) Pressure (bar) Flowrate (kgmole/hr) Flowrate (kg/hr) E09 Duty *10 6 Kcal/hr 20/33

21 Calculation of total flowrate of ethylene CV05 Outlet Pressure : bar CV06 Outlet Pressure : bar 21/33

22 CN3 Condition & Result Total Flowrate of ethylene Kgmol/hr = kg/hr 22/33

23 Two-Stage Refrigeration Cycle K05 Outlet Pressure : bar diabatic Efficiency : 70% K04 Outlet Pressure : bar diabatic Efficiency : 70% E10 Pressure drop(hot Side) : 0 bar Hot Product Temperature : 45 E11 Pressure drop(hot Side) : 0.5 bar Hot Product Liquid Fraction : 1 CV05 Outlet Pressure : bar F05/F06 diabatic : duty 0 E09 Pressure drop(hot Side) : 0.5bar Hot Product Liquid Fraction : 1 CV06 Outlet Pressure : bar Stream41 Temperature : -37 ubble Point Component : Ethylene Total Fluid Flowrate : kg/hr E04/E05 Pressure drop(hot Side) : 0.5 bar Cold Product Liquid Fraction : 0 23/33

24 Three-Stage Refrigeration of propane 24/33

25 Three-Stage Refrigeration System Second Stage Discharge Pressure(K07) = Second Suction Pressure * Ratio per stage = * = bar First Stage Discharge Pressure(K06) = First Suction Pressure * Ratio per stage = * = bar Ratio per stage K08 73 M08 K07 71 M07 K06 M E12 62 V V Condenser Heat Duty of C2 - Refrigeration Cycle(E11) = *10 6 Kcal/hr 66 V CV07 62 F07 SP05 CV08 F08 SP06 CV09 F09 SP07 66 E11 62 L L L E01 E02 E03 Temperature of Refrigerator(E01) = Dew point temperature of propane at bar = o C Temperature of Refrigerator(E02) = Dew point temperature of propane at bar = o C 25/33

26 Calculation of total flowrate of propane Stream Name Temperature ( ) Pressure (bar) Flowrate (kgmole/hr) Flowrate (kg/hr) E09 Duty *10 6 Kcal/hr 26/33

27 Calculation of total flowrate of propane CV07 Outlet Pressure : bar CV08 Outlet Pressure : bar CV09 Outlet Pressure : bar 27/33

28 CN5 Condition & Result Total Flowrate of propane Kgmol/hr = kg/hr 28/33

29 Three-Stage Refrigeration Cycle K08 Outlet Pressure : bar diabatic Efficiency : 70% K07 Outlet Pressure : bar diabatic Efficiency : 70% K06 Outlet Pressure : bar diabatic Efficiency : 70% E12 Pressure drop(hot Side) : 0.5bar Hot Product Liquid Fraction : 1 CV07 Outlet Pressure : bar CV08 Outlet Pressure : bar CV09 Outlet Pressure : bar E09 Pressure drop(hot Side) : 0.5bar Hot Product Liquid Fraction : 1 F07/F08/F09 diabatic : duty 0 Stream61 Temperature : 45 ubble Point Component : Propane Total Fluid Flowrate : kg/hr E01/E02/E03 Pressure drop(hot Side) : 0.5 bar Cold Product Liquid Fraction : 0 29/33

30 Multi-Stage Cascade Refrigeration Cycle & Results 30/33

31 Multi-Stage Cascade Refrigeration Cycle 31/33

32 Results of Calculator Refrigerator Contents ctual Work (kw) K E+04 Propane K E+04 K E+04 Ethylene K E+04 K E+04 K E+04 Methane K E+03 K E+03 Total E+05 LNG Flowrate (kg/hr) Specific Power for produced LNG [kwh/kg] = kwh/kg LNG 32/33

33 Thank you for your attention