Method For Processing Hydrocarbon Pyrolysis Effluent

Abstract

A method and system are disclosed for treating the effluent from a hydrocarbon pyrolysis unit employing a small primary fractionator. The method comprises cooling the effluent from a furnace through a first heat exchanger, a vapor-liquid separator, and a second heat exchanger before it is passed to a fractionator for further processing. These heat exchangers may also be utilized to heat a utility fluid as part of the cooling process. Further, one or more generators and a third heat exchanger may also be used to assist in heat recovery for the process.

1 . A method for cracking a hydrocarbon feed, the method comprising:
 providing a hydrocarbon feed to a hydrocarbon pyrolysis unit to create cracked effluent;   passing at least a portion of the cracked effluent from the hydrocarbon pyrolysis unit through a first heat exchanger;   separating the at least a portion of the cracked effluent from the first heat exchanger into a gaseous effluent and a liquid effluent;   passing at least a portion of the gaseous effluent through a second heat exchanger;   passing at least a portion of the effluent from the second heat exchanger to a fractionator;   recovering heat from the at least a portion of the effluent in the second heat exchanger by passing a utility fluid through the second heat exchanger; and   recovering heat from the at least a portion of the cracked effluent in the first heat exchanger by passing the utility fluid from the second heat exchanger through the first heat exchanger.   
     
     
         2 . The method of  claim 1 , comprising passing the utility fluid from the first heat exchanger through the hydrocarbon pyrolysis unit to heat the utility fluid. 
     
     
         3 . The method of  claim 1 , comprising passing the at least a portion of the effluent from the second heat exchanger to one or more steam generators before passing the at least a portion of the effluent from the second heat exchanger to the fractionator. 
     
     
         4 . The method of  claim 3 , comprising passing the at least a portion of the effluent from the one or more steam generators through a third heat exchanger before passing the at least a portion of the effluent from the one or more steam generators to the fractionator. 
     
     
         5 . The method of  claim 4 , comprising recovering heat from the at least a portion of the effluent from the one or more steam generators in the third heat exchanger by passing the utility fluid through the third heat exchanger before passing the at least a portion of the effluent from the one or more steam generators to the fractionator. 
     
     
         6 . The method of  claim 3 , comprising adjusting valves on the one or more steam generators to control the heat recovery from the at least a portion of the effluent passing through the one or more steam generators. 
     
     
         7 . The method of  claim 1 , wherein the utility fluid is heated in a deaerator prior to passing through the first heat exchanger. 
     
     
         8 . The method of  claim 1 , comprising driving a turbine with the heated utility fluid from the first heat exchanger. 
     
     
         9 . The method of  claim 1 , wherein the at least a portion of the cracked effluent from the first heat exchanger is cooled in a direct quench to at least a temperature at which tar, formed by reaction among constituents of the effluent, condenses, prior to the separating the gaseous effluent and the liquid effluent. 
     
     
         10 . A hydrocarbon cracking system comprising:
 a hydrocarbon pyrolysis unit configured to:
 receive a hydrocarbon feed; and 
 create a cracked effluent from the hydrocarbon feed; 
   a first heat exchanger in fluid communication with the hydrocarbon pyrolysis unit and configured to:
 cool at least a portion of the cracked effluent from the hydrocarbon pyrolysis unit; and 
 heat at least a portion of a utility fluid; and 
   a separator in fluid communication with the first heat exchanger and configured to separate the at least a portion of the cracked effluent into liquid effluent and gaseous effluent;   a second heat exchanger in fluid communication with the separator and configured to:
 cool at least a portion of the effluent from the separator; 
 heat the utility fluid prior to the first heat exchanger receiving the at least a portion of the utility fluid; and 
   a fractionator in fluid communication with the second heat exchanger and configured to receive the at least a portion of the effluent from the second heat exchanger.   
     
     
         11 . The system of  claim 10 , wherein the hydrocarbon pyrolysis unit is configured to heat the at least a portion of a utility fluid from the first heat exchanger, wherein the at least a portion of a utility fluid and the at least a portion of the cracked effluent are maintained in separate non-commingling streams in the hydrocarbon pyrolysis unit. 
     
     
         12 . The system of  claim 10 , comprising one or more steam generators in fluid communication between the second heat exchanger and the fractionator and configured to pass the at least a portion of the effluent from the second heat exchanger to the fractionator. 
     
     
         13 . The system of  claim 12 , comprising a third heat exchanger in fluid communication between the one or more steam generators and the fractionator and configured to cool the at least a portion of the effluent before passing the at least a portion of the effluent to the fractionator. 
     
     
         14 . The system of  claim 13 , wherein the third heat exchanger is in fluid communication with the second heat exchanger and configured to recover heat from the at least a portion of the effluent by passing the utility fluid through the third heat exchanger prior to the second heat exchanger receiving the utility fluid; and wherein the utility fluid and the at least a portion of the effluent are maintained in separate non-commingling streams in the second heat exchanger. 
     
     
         15 . The system of  claim 14 , comprising a bypass valve coupled between a source of the utility fluid, the first heat exchanger and the third heat exchanger and configured to:
 in a first position, restrict a first portion of the utility fluid from passing to the third heat exchanger from the source and direct a first remaining portion of the utility fluid to the first heat exchanger via a bypass line; and   in a second position, direct a second portion of the utility fluid to pass to the third heat exchanger from the source and restrict a second remaining portion of the utility fluid from passing through the bypass line to the first heat exchanger.   
     
     
         16 . The system of  claim 12 , comprising a control valve coupled to at least one of the one or more steam generators and configured to control the cooling of the at least a portion of the effluent passing through the one or more steam generators. 
     
     
         17 . The system of  claim 10 , comprising a deaerator in fluid communication with the second heat exchanger and configured to preheat the utility fluid prior to passing the utility fluid to the second heat exchanger. 
     
     
         18 . The system of  claim 10 , wherein the first heat exchanger is configured to cool the at least a portion of the cracked effluent from the hydrocarbon pyrolysis unit and provide the at least a portion of the cracked effluent to a direct quench that cools the at least a portion of the cracked effluent to a temperature at which tar, formed by reaction among constituents of the at least a portion of the cracked effluent, condenses. 
     
     
         19 . The system of  claim 10 , comprising a drive turbine configured to receive the at least a portion of the heated utility fluid from the hydrocarbon pyrolysis unit. 
     
     
         20 . The system of  claim 10 , wherein the utility fluid and the at least a portion of the effluent are maintained in separate non-commingling streams. 
     
     
         21 . A method for steam cracking a hydrocarbon feed, the method comprising:
 providing a hydrocarbon feed to a hydrocarbon pyrolysis unit to create a cracked effluent;   separating at least a portion of the cracked effluent from the hydrocarbon pyrolysis unit, wherein gaseous effluent is separated from liquid effluent including steam cracked tar;   cooling at least a portion of the gaseous effluent in a first heat exchanger;   passing at least a portion of the effluent from the first heat exchanger to one or more steam generators;   cooling the at least a portion of the effluent from the one or more steam generators in a second heat exchanger; and   passing the at least a portion of the effluent from the second heat exchanger to a fractionator.   
     
     
         22 . The method of  claim 21 , comprising passing the at least a portion of the cracked effluent from the hydrocarbon pyrolysis unit through a third heat exchanger before passing the at least a portion of the cracked effluent to the separator. 
     
     
         23 . The method of  claim 22 , comprising heating a utility fluid by passing the utility fluid through the hydrocarbon pyrolysis unit and using the heated utility fluid in an additional process. 
     
     
         24 . The method of  claim 23 , recovering heat from the at least a portion of the effluent in the first heat exchanger by passing the utility fluid by through the first heat exchanger prior to passing the utility fluid through hydrocarbon pyrolysis unit. 
     
     
         25 . The method of  claim 24 , comprising recovering heat from the at least a portion of the effluent in the second heat exchanger by passing the utility fluid through the second heat exchanger prior to passing the utility fluid through the first heat exchanger. 
     
     
         26 . The method of  claim 25 , comprising adjusting valves on the one or more steam generators to control the heat recovery from the at least a portion of the effluent passing through the one or more steam generators. 
     
     
         27 . The method of  claim 24 , wherein the utility fluid is heated in a deaerator prior to passing through the first heat exchanger. 
     
     
         28 . The method of  claim 22 , wherein the at least a portion of the cracked effluent is cooled in the third heat exchanger to at least a temperature above the temperature at which tar, formed by reaction among constituents of the effluent, condenses. 
     
     
         29 . The method of  claim 23 , wherein using the heated utility fluid in the additional process comprises driving a turbine with the heated utility fluid. 
     
     
         30 . A gaseous effluent handling system comprising:
 a hydrocarbon pyrolysis unit configured to:
 receive a hydrocarbon feed; and 
 create a cracked effluent from the hydrocarbon feed; and 
   a separator in fluid communication with the hydrocarbon pyrolysis unit and configured to separate liquid effluent having steam cracked tar and gaseous effluent from at least a portion of the cracked effluent from the hydrocarbon pyrolysis unit; and   a first heat exchanger in fluid communication with the separator and configured to cool at least a portion of the gaseous effluent from the separator;   one or more steam generators in fluid communication with the first heat exchanger and configured to receive the at least a portion of the effluent from the first heat exchanger;   a second heat exchanger in fluid communication with the one or more generators and configured to cool the at least a portion of the effluent from the one or more steam generators; and   a fractionator in fluid communication with the second heat exchanger and configured to receive the at least a portion of the effluent from the second heat exchanger.   
     
     
         31 . The system of  claim 30 , comprising a third heat exchanger in fluid communication between the separator and the hydrocarbon pyrolysis unit and configured to cool the at least a portion of the cracked effluent passing through the third heat exchanger to the separator. 
     
     
         32 . The system of  claim 30 , wherein the hydrocarbon pyrolysis unit is configured to heat a utility fluid by passing the utility fluid through the hydrocarbon pyrolysis unit. 
     
     
         33 . The system of  claim 32 , wherein the first heat exchanger is configured to recover heat from the at least a portion of the effluent in the first heat exchanger by passing the utility fluid by through the first heat exchanger prior to passing the utility fluid through hydrocarbon pyrolysis unit. 
     
     
         34 . The system of  claim 33 , wherein the second heat exchanger is configured to recover heat by passing the utility fluid through the second heat exchanger prior to passing the utility fluid through the first heat exchanger. 
     
     
         35 . The system of  claim 34 , comprising one or more valves coupled to the one or more steam generators and configured to adjust the heat recovery from the at least a portion of the effluent passing through the one or more steam generators.