Utilization of process heat by-product

Abstract

Heat recovery systems and methods for producing electrical and/or mechanical power from a process heat by-product are provided. Sources of process heat by-product include hot flue gas streams, high temperature reactors, steam generators, gas turbines, diesel generators, and process columns. Heat recovery systems and methods include a process heat by-product stream for indirectly heating a working fluid of an organic Rankine cycle. The organic Rankine cycle includes a heat exchanger, a turbine-generator system for producing power, a condenser heat exchanger, and a pump for recirculating the working fluid to the heat exchanger.

1 . A process for utilizing process heat by-product from refinery operations, comprising:
 a first sub-process, a second sub-process, and a third sub-process, the first sub-process comprising the steps of:   a) directing process heat by-product from a refinery operation to a first heater;   b) thermally contacting in said first heater the process heat by-product with a first working fluid to cool the process heat by-product to form a cooled by-product;   c) exhausting the cooled by-product to atmosphere;   the second sub-process comprising the steps of:   d) heating in said first heater the first working fluid to form a first heated working fluid;   e) directing the first heated working fluid to a second heater;   f) thermally contacting in said second heater the first heated working fluid with a second working fluid to cool the first heated working fluid to form a first cooled working fluid;   g) passing the first cooled working fluid through a pump to form said first working fluid; and   the third sub-process comprising the steps of:   h) heating in said second heater the second working fluid to form a second heated working fluid;   i) passing the second heated working fluid through a turbine to form an expanded working fluid, wherein said passing of the second heated working fluid through the turbine drives a generator for production of one of electricity and mechanical power;   j) passing the expanded working fluid through at least one heat exchanger to form a condensed working fluid; and   k) passing the condensed working fluid through at least one pump to form said second working fluid;   wherein the first and second sub-processes are linked via the first heater, wherein the second and third sub-processes are linked via the second heater, and wherein first, second, and third sub-processes occur simultaneously.   
     
     
         2 . The process of  claim 1 , wherein the at least one heat exchanger is selected from the group consisting of air-cooled condensers and water-cooled condensers. 
     
     
         3 . The process of  claim 1 , wherein said process heat by-product comprises flue gas or waste heat from refinery operations. 
     
     
         4 . The process of  claim 1 , wherein said process heat by-product comprises flue gas from a fluid catalytic cracking unit. 
     
     
         5 . The process of  claim 1 , wherein said process heat by-product comprises heat by-product generated by
 directing flue gas from a fluid catalytic cracking regenerator to a waste heat steam generator for generating steam,   passing said flue gas through an electrostatic precipitator to remove catalyst fines present in the flue gas, and   recovering the process heat by-product from the flue gas exiting the electrostatic precipitator.   
     
     
         6 . The process of  claim 1 , wherein said process heat by-product comprises heat by-product generated by
 directing a flue gas from a fluid catalytic cracking regenerator to a boiler, wherein the flue gas comprises carbon monoxide,   combusting the carbon monoxide in the boiler to generate steam,   passing the flue gas through an electrostatic precipitator to remove catalyst fines present in the flue gas, and   recovering the process heat by-product from the flue gas exiting the electrostatic precipitator.   
     
     
         7 . The process of  claim 1 , wherein said process heat by-product comprises recovered heat from a high temperature reactor. 
     
     
         8 . The process of  claim 7 , wherein the high temperature reactor is a fired heater or an incinerator. 
     
     
         9 . The process of  claim 7 , wherein said heater is integral to a convection section of the high temperature reactor. 
     
     
         10 . The process of  claim 1 , wherein the second working fluid is selected from the group consisting of organic working fluids and refrigerants. 
     
     
         11 . The process of  claim 1 , wherein the step of heating the second working fluid to form the second heated working fluid comprises vaporizing the second working fluid. 
     
     
         12 . The process of  claim 1 , wherein the step of heating the second working fluid to form the second heated working fluid comprises vaporizing the second working fluid within a supercritical process. 
     
     
         13 . A process for utilizing waste heat by-product, comprising:
 a first sub-process, a second sub-process, and a third sub-process, the first sub-process comprising the steps of:   a) directing waste heat by-product to a first heater;   b) thermally contacting in said first heater the waste heat by-product with a first working fluid to cool the waste heat by-product to form a cooled by-product;   c) exhausting the cooled by-product;   the second sub-process comprising the steps of:   d) heating in said first heater the first working fluid to form a first heated working fluid;   e) directing the first heated working fluid to a second heater;   f) thermally contacting in said second heater the first heated working fluid with a second working fluid to cool the first heated working fluid to form a first cooled working fluid;   g) passing the first cooled working fluid through at least one pump to form said first working fluid; and   the third sub-process comprising the steps of:   h) heating in said second heater the second working fluid to form a second heated working fluid;   i) passing the second heated working fluid through a turbine to form an expanded working fluid, wherein said passing of the second heated working fluid through the turbine that drives a generator for production of one of electricity and mechanical power;   j) passing the expanded working fluid through at least one heat exchanger to form a condensed working fluid; and   k) passing the condensed working fluid through a pump to form said second working fluid;   wherein the first and second sub-processes are linked via the first heater, wherein the second and third sub-processes are linked via the second heater, and wherein first, second, and third sub-processes occur simultaneously.   
     
     
         14 . The process of  claim 13 , wherein the at least one heat exchanger is selected from the group consisting of air-cooled condensers and water-cooled condensers. 
     
     
         15 . The process of  claim 13 , further comprising the step of directing the cooled by-product to one of an incinerator, a scrubber, and a stack prior to exhausting the cooled by-product to the atmosphere. 
     
     
         16 . The process of  claim 13 , wherein said waste heat by-product comprises waste heat from a steam generator. 
     
     
         17 . The process of  claim 13 , wherein said waste heat by-product is generated by
 directing water into a steam generator,   heating the water with a heated air stream to form steam and the waste heat by-product.   
     
     
         18 . The process of  claim 17 , further comprising the step of diverting a portion of the waste heat by-product through a diverter valve for discharging to atmosphere. 
     
     
         19 . The process of  claim 13 , wherein said waste heat by-product comprises waste heat from a gas turbine. 
     
     
         20 . The process of  claim 13 , wherein said waste heat by-product is generated by
 directing fuel into a gas turbine, and   combusting the fuel in the gas turbine to generate power and the waste heat by-product.   
     
     
         21 . The process of  claim 13 , wherein the second working fluid is selected from the group consisting of organic working fluids and refrigerants. 
     
     
         22 . The process of  claim 13 , wherein the step of heating the second working fluid to form the second heated working fluid comprises vaporizing the second working fluid. 
     
     
         23 . The process of  claim 13 , wherein the step of heating the second working fluid to form the second heated working fluid comprises vaporizing the second working fluid within a supercritical process. 
     
     
         24 . A system for utilizing a heat by-product, comprising:
 an organic Rankine cycle comprising a heater, a turbine and generator, at least one heat exchanger, and a pump, wherein the at least one heat exchanger is selected from air-cooled heat exchangers and water-cooled heat exchangers; and   a heat source, wherein the heat source is one selected from process heat by-products from refinery operations and waste heat by-products.