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 directly 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 and a second sub-process, the first sub-process comprising the steps of:   a) directing process heat by-product from a refinery operation to a heater;   b) thermally contacting in said heater the process heat by-product with a working fluid to cool the process heat by-product to form a cooled by-product;   c) exhausting the cooled by-product to atmosphere;   and the second sub-process comprising the steps of:   d) heating in said heater the working fluid to form a heated working fluid;   e) passing the heated working fluid through a turbine to form an expanded working fluid, wherein said passing of the heated working fluid through the turbine drives a generator for production of one of electricity and mechanical power;   f) passing the expanded working fluid through at least one heat exchanger to form a condensed working fluid; and   g) passing the condensed working fluid through at least one pump to form said working fluid;   wherein the first and second sub-processes are linked via the heater, and wherein first and second 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 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 working fluid to form the heated working fluid comprises vaporizing the working fluid. 
     
     
         12 . The process of  claim 1 , wherein the step of heating the working fluid to form the heated working fluid comprises vaporizing the working fluid within a supercritical process. 
     
     
         13 . A process for utilizing waste heat by-product, comprising:
 a first sub-process and a second sub-process, the first sub-process comprising the steps of:   a) directing waste heat by-product to a heater;   b) thermally contacting in said heater the waste heat by-product with a working fluid to cool the waste heat by-product to form a cooled by-product;   c) exhausting the cooled by-product to atmosphere;   and the second sub-process comprising the steps of:   d) heating in said heater the working fluid to form a heated working fluid;   e) passing the heated working fluid through a turbine to form an expanded working fluid, wherein said passing of the heated working fluid through the turbine drives a generator for production of one of electricity and mechanical power;   f) passing the expanded working fluid through at least one heat exchanger to form a condensed working fluid; and   g) passing the condensed working fluid through at least one pump to form said working fluid;   wherein the first and second sub-processes are linked via the heater, and wherein first and second 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 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 working fluid to form the heated working fluid comprises vaporizing the working fluid. 
     
     
         23 . The process of  claim 13 , wherein the step of heating the working fluid to form the heated working fluid comprises vaporizing the working fluid within a supercritical process. 
     
     
         24 . A process for utilizing a heat by-product, comprising:
 a first sub-process and a second sub-process, the first sub-process comprising the steps of:   a) directing the heat by-product to a heater;   b) thermally contacting in said heater the heat by-product with a working fluid to cool the heat by-product to form a cooled by-product;   c) exhausting the cooled by-product to atmosphere;   and the second sub-process comprising the steps of:   d) heating in said heater the working fluid to form a heated working fluid;   e) passing the heated working fluid through a turbine to form an expanded working fluid, wherein said passing of the heated working fluid through the turbine powers a generator for production of one of electricity and mechanical power;   f) passing the expanded working fluid through at least one heat exchanger to form a condensed working fluid; and   g) passing the condensed working fluid through at least one pump to form said working fluid;   wherein the first and second sub-processes are linked via the heater, and wherein first and second sub-processes occur simultaneously.