Efficient cracking furnace system with reduced emission of co2

Abstract

A cracking furnace system for converting a hydrocarbon feedstock into cracked gas includes a convection section, a radiant section and a cooling section. The convection section includes a plurality of convection banks configured to receive only a hydrocarbon feedstock and a diluent. The radiant section includes a firebox comprising at least oxygen or oxygen enriched air burners and several radiant coils configured to heat up the feedstock to a temperature allowing a pyrolysis reaction. The cooling section includes at least two transfer line exchangers (TLE), a primary transfer line exchanger (PTLE) and a secondary transfer line exchanger (STLE).

1 - 8 . (canceled) 
     
     
         9 . A method for cracking hydrocarbon feedstock in a cracking furnace system, the method comprising:
 preheating a feedstock in a convection section at a temperature between 50° C. and 180° C.;   mixing the hydrocarbon feedstock after preheating with a diluent to form a mixed feedstock-diluent;   preheating the mixed feedstock-diluent in a secondary transfer line exchanger at a temperature between 250° C. and 700° C.;   cracking the mixed feedstock-diluent after preheating in the radiant section by oxygen or oxygen enriched air combustion to produce cracked gas;   cooling the cracked gas in a primary transfer line exchanger;   cooling the cracked gas exiting the primary transfer line exchanger further in the secondary transfer line exchanger; and   producing a saturated super high-pressure steam in the primary transfer line exchanger.   
     
     
         10 . The method according to  claim 9 , wherein the saturated super high-pressure steam is generated from water coming from a steam drum. 
     
     
         11 . The method according to  claim 9 , wherein the saturated super high-pressure steam produced is sent into a steam drum. 
     
     
         12 . The method according to  claim 9 , wherein the diluent is dilution steam. 
     
     
         13 . The method according to  claim 12 , wherein the dilution steam is produced outside the cracking furnace system. 
     
     
         14 . The method according to  claim 9 , wherein cracking the mixed feedstock-diluent comprises controlling a combustion temperature in the radiant section by dilution of fuel and oxygen or oxygen enriched air. 
     
     
         15 . The method according to  claim 9 , wherein the oxygen enriched air comprises more than 21% oxygen. 
     
     
         16 . The method according to  claim 9 , wherein cracking the mixed feedstock-diluent includes producing flue gas at a temperature between 950° C. and 1300° C. and sending the flue gas to the convection section. 
     
     
         17 . The method according to  claim 16 , wherein cracking the mixed feedstock-diluent includes producing flue gas at a temperature between 1000° C. and 1150° C. 
     
     
         18 . The method according to  claim 9 , wherein preheating the feedstock in the convection section includes preheating the feedstock in the convection section at a temperature between 150° C. and 160° C. 
     
     
         19 . The method according to  claim 9 , wherein preheating the mixed feedstock-diluent in the secondary transfer line exchanger includes preheating the mixed feedstock-diluent in the secondary transfer line exchanger at a temperature between 275° C. and 500° C.