Olefins production process

Abstract

The invention relates to a process for producing olefins from a feed stream containing hydrocarbons by pyrolytic cracking of the hydrocarbons in a cracker furnace, said process comprising: pre-heating the feed stream outside the cracker furnace; feeding the pre-heated feed stream to a tube in the convection section of the cracker furnace; further pre-heating the feed stream in the convection section; feeding the further pre-heated feed stream to a tube in the radiant section of the cracker furnace; pre-heating an oxygen containing stream; contacting the pre-heated oxygen containing stream with a fuel gas in a burner in the radiant section; and pyrolytic cracking the feed stream in the radiant section resulting in an effluent containing olefins.

1 . A process for producing olefins from a feed stream containing hydrocarbons by pyrolytic cracking of the hydrocarbons in a cracker furnace, said process comprising:
 pre-heating the feed stream outside the cracker furnace;   feeding the pre-heated feed stream to a tube in the convection section of the cracker furnace;   further pre-heating the feed stream in the convection section;   feeding the further pre-heated feed stream to a tube in the radiant section of the cracker furnace;   pre-heating an oxygen containing stream;   contacting the pre-heated oxygen containing stream with a fuel gas in a burner in the radiant section; and   pyrolytic cracking the feed stream in the radiant section resulting in an effluent containing olefins.   
     
     
         2 . The process according to  claim 1 , wherein the feed stream containing hydrocarbons is pre-heated outside the cracker furnace to a temperature which is at least 75° C. and which is at most 550° C. 
     
     
         3 . The process according to  claim 1 , wherein one or more of the following heat sources is or are used in pre-heating the feed stream containing hydrocarbons outside the cracker furnace through indirect heat exchange between the feed stream and such heat source or heat sources: (i) very high pressure steam having a pressure of from greater than 70 bara to 130 bara; (ii) high pressure steam having a pressure of from greater than 30 bara to 70 bara; (iii) medium pressure steam having a pressure of from greater than 10 bara to 30 bara; (iv) low pressure steam having a pressure of from greater than atmospheric pressure to 10 bara; and (v) another heat source having a temperature of from greater than 50° C. to 100° C. 
     
     
         4 . The process according to  claim 1 , wherein the olefins-containing effluent from the radiant section is used to provide pressurized steam through indirect heat exchange, in a first transfer line exchanger, between said effluent from the radiant section and utility water, and at least a portion of the cracker effluent coming from the first transfer line exchanger is sent to a next transfer line exchanger arranged in series wherein at least a portion of the feed stream containing hydrocarbons is pre-heated by indirect heat exchange with said effluent from the first transfer line exchanger, and wherein a transfer line exchanger is a system which comprises one or more indirect heat exchangers. 
     
     
         5 . The process according to  claim 1 , further comprising:
 pre-heating utility water outside the cracker furnace; and   generating pressurized steam from the pre-heated utility water through indirect heat exchange with effluent from the radiant section.   
     
     
         6 . The process according to  claim 1 , wherein the oxygen containing stream is pre-heated to a temperature which is at least 70° C. and which is at most 550° C. 
     
     
         7 . The process according to  claim 1 , wherein the oxygen containing stream is pre-heated inside the cracker furnace through indirect heat exchange between the oxygen containing stream and flue gas in the convection section. 
     
     
         8 . The process according to  claim 1 , wherein the feed stream containing hydrocarbons is not pre-heated in the convection section of the cracker furnace before pre-heating the feed stream outside the cracker furnace.