Energy efficient steam cracking process
A method for steam cracking of a hydrocarbon feed is disclosed. The method can include heating a hydrocarbon feed stream with a first quench water stream to form a heated hydrocarbon feed stream and a second quench water stream having a temperature lower than the first quench water stream, steam cracking the heated hydrocarbon feed stream to form a cracked stream comprising cracked gases, contacting the cracked stream with a quench water to form a gaseous stream comprising quenched cracked gases and a crude water stream comprising heated quench water and pyrolysis gasoline, and separating the crude water stream to form the first quench water stream.
1. A method for steam cracking of hydrocarbons, the method comprising:
(a) heating a hydrocarbon feed stream with a first quench water stream to form a heated hydrocarbon feed stream and a second quench water stream having a temperature lower than the first quench water stream;
(b) steam cracking the heated hydrocarbon feed stream to form a cracked stream comprising cracked gases;
(c) contacting the cracked stream with quench water to form a gaseous stream comprising quenched cracked gases and a crude water stream comprising heated quench water and pyrolysis gasoline; and
(d) separating the crude water stream to form the first quench water stream.
2. The method of claim 1 , wherein the method further comprises, prior to steam cracking, heating the heated hydrocarbon feed stream with a low pressure steam stream to form a second heated hydrocarbon feed stream and the second heated hydrocarbon feed stream is steam cracked in step (b).
3. The method of claim 2 , wherein the low pressure steam stream has a pressure of 0.35 MPa to 0.45 MPa, and/or temperature of 220° C. to 280° C.
4. The method of claim 2 , wherein the second heated hydrocarbon feed stream has a temperature of 125° C. to 130° C.
5. The method of claim 2 , wherein the heated hydrocarbon feed stream is heated with the low pressure steam stream by heat exchange with and/or without direct contact.
6. The method of claim 2 , wherein the method further comprises, prior to steam cracking, heating the second heated hydrocarbon feed stream with a high pressure steam stream to form a third heated hydrocarbon feed stream and the third heated hydrocarbon feed stream is steam cracked in step (b).
7. The method of claim 6 , wherein the high pressure steam stream has a pressure of 4 MPa to 4.5 MPa, and/or temperature of 370° C. to 390° C.
8. The method of claim 6 , wherein the third heated hydrocarbon feed stream has a temperature of 135° C. to 145° C.
9. The method of claim 6 , wherein the second heated hydrocarbon feed stream is heated with the high pressure steam stream by heat exchange with and/or without direct contact.
10. The method of claim 1 , wherein the heated hydrocarbon feed stream or second heated hydrocarbon feed stream or the third heated hydrocarbon feed stream is contacted with a dilution steam stream to form a mixed stream and the mixed stream is cracked in step (b).
11. The method of claim 1 , wherein the first quench water stream has a temperature of 76° C. to 84° C.
12. The method of claim 1 , wherein the heated hydrocarbon feed stream has a temperature of 5° C. to 40° C.
13. The method of claim 1 , wherein the second quench water stream has a temperature of 78° C. to 83.5° C.
14. The method of claim 1 , wherein the second quench water stream is cooled with a quench water cooler to form the quench water.
15. The method of claim 1 , wherein the quench water has a temperature of 35° C. to 42° C.
16. The method of claim 1 , wherein the hydrocarbon feed stream is heated with the first quench water stream by heat exchange with and/or without direct contact.
17. The method of claim 1 , wherein the cracked stream is contacted with the quench water in a quench water tower.
18. The method of claim 1 , wherein the crude water stream is separated in a quench water separator.
19. The method of claim 1 , wherein the steam cracking is performed at a temperature of 820° C. to 900° C., and/or a pressure of 0.05 MPa to 0.1 MPa.
20. The method of claim 1 , wherein the hydrocarbon feed stream comprises naphtha, liquid petroleum gas, ethane, or propane or any combination thereof.