Apparatus and method for gas-liquid separation of a liquid, gas and water vapour mixture from a fischer-tropsch reactor

A method comprising the steps of:

• a) producing a product stream comprising a mixture of liquid and gaseous hydrocarbon products and water vapour using a Fischer-Tropsch reactor;
• b) feeding product stream comprising the mixture of liquid and gaseous hydrocarbon products and water vapour from the Fischer-Tropsch reactor into a first vapour-liquid separator inside which the product stream is separated into a first liquid comprising a first cut of the hydrocarbon products and a first gas stream comprising gaseous hydrocarbon products and water vapour, wherein the product stream is fed to the first vapour-liquid separator at a temperature in a range of 120 to 200° C.;
• c) collecting the first liquid at a liquid outlet of the first vapour-liquid separator;
• d) discharging the first gas stream from a gas outlet of the first vapour-liquid separator and feeding the first gas stream through a first cooler to apply cooling to the first gas stream to condense a portion of the gaseous hydrocarbon products and water vapour to form a first cooled mixture;
• e) feeding the first cooled mixture from the first cooler into a second vapour-liquid separator inside which the first cooled mixture is separated into a second liquid comprising a second cut of the hydrocarbon products and water, and a second gas stream comprising gaseous hydrocarbon products and water vapour, wherein the first cooled mixture is fed to the second vapour-liquid separator at a temperature in a range of 80 to 120° C.;
• f) collecting the second liquid at a liquid outlet of the second vapour-liquid separator;
• g) discharging the second gas stream from a gas outlet of the second vapour-liquid separator;
• h) feeding the second gas stream from the gas outlet of the second vapour-liquid separator through a second cooler to apply cooling to the second gas stream to condense a portion of the gaseous hydrocarbon products and water vapour to form a second cooled mixture;
• i) feeding at a first temperature the second cooled mixture from the second cooler into a third vapour-liquid separator inside which the second cooled mixture is separated into a third liquid comprising a third cut of the hydrocarbon products and water, and a third gas stream comprising gaseous hydrocarbon products and water vapour, wherein the first temperature is more than 50° C. and less than or equal to 75° C.;
• j) collecting the third liquid at a liquid outlet of the third vapour-liquid separator;
• k) discharging the third gas stream from a gas outlet of the third vapour-liquid separator;
• l) feeding the third gas stream from the gas outlet of the third vapour-liquid separator through a third cooler to apply cooling to the third gas stream to condense a portion of the remainder of the hydrocarbon products and water vapour to form a third cooled mixture;
• m) feeding at a second temperature the third cooled mixture from the third cooler into a fourth vapour-liquid separator inside which the third cooled mixture is separated into a fourth liquid comprising a fourth cut of the hydrocarbon products and water, and a fourth gas stream, wherein the second temperature is less than the first temperature, the second temperature being from 20 to 50° C.;
• n) collecting the fourth liquid at a liquid outlet of the fourth vapour-liquid separator;
• and
• o) discharging the fourth gas stream from a gas outlet of the fourth vapour-liquid separators.