Near zero emissions production of clean high pressure steam

Abstract

Substantially pure high pressure steam is produced within a high pressure heat exchanger. Heat for the high pressure heat exchanger is provided from an outlet of an oxy-fuel combustion gas generator which discharges a steam/CO 2 mixture at high pressure and temperature. The gas generator combusts oxygen and hydrocarbon fuel and mixes with water which can include contaminates therein in the form of dissolved solids or hydrocarbons. A separator is typically provided downstream of the gas generator and upstream of the heat exchanger and the steam/CO 2 mixture is discharged from the gas generator at saturation temperature. A water fraction of the steam/CO 2 mixture is discharged from the separator along with dissolved solids in concentrated brine form. The water heated into steam by the heat exchanger can be at least partially water separated within a condenser downstream of the heat exchanger.

What is claimed is: 
     
         1 . A zero or near zero emissions system for producing substantially pure high pressure steam, comprising in combination:
 a high pressure source of oxygen having a pressure at least ten times standard atmospheric pressure;   a high pressure source of hydrocarbon fuel having a pressure at least ten times standard atmospheric pressure;   a high pressure source of water having a pressure at least ten times atmospheric pressure;   a gas generator having a fuel inlet, an oxidizer inlet and a water inlet;   said oxidizer inlet coupled to said high pressure source of oxygen, said high pressure source of oxygen being a majority oxygen;   said fuel inlet coupled to said high pressure hydrocarbon fuel source;   said water inlet coupled to said high pressure source of water;   said gas generator combusting the hydrocarbon fuel and the oxygen to produce steam and CO 2  and adding water from the water inlet to the produced steam and CO 2  before said outlet to provide a steam/CO 2  mixture discharged from said gas generator at said outlet; and   a high pressure heat exchanger downstream of said outlet of said gas generator having a high pressure steam/CO 2  mixture line downstream of said gas generator outlet with a pressure in said high pressure steam/CO 2  mixture line at least ten times greater than atmospheric pressure and a substantially pure high pressure water line with a pressure at least ten times greater than atmospheric pressure, said high pressure steam/CO 2  mixture line in heat transfer relationship with said high pressure substantially pure water line to heat water in said substantially pure water line into substantially pure high pressure steam with a pressure at least ten times greater than atmospheric pressure.   
     
     
         2 . The system of  claim 1  wherein no expander is located between said outlet of said gas generator and said high pressure steam/CO 2  mixture line of said heat exchanger. 
     
     
         3 . The system of  claim 1  wherein a dissolved solids separator is located between said outlet of said gas generator and said high pressure steam/CO 2  mixture line of said heat exchanger, said separator including an inlet for the steam/CO 2  mixture from said gas generator, a discharge for the steam/CO 2  mixture and an output for a concentrated brine including solids removed from the steam/CO 2  mixture discharged from said gas generator outlet. 
     
     
         4 . The system of  claim 3  wherein a reheater is located between said discharge of said separator and said high pressure steam/CO 2  mixture line of said heat exchanger, said reheater including a fuel inlet coupled to said source of hydrocarbon fuel and an oxidizer inlet coupled to said source of high pressure oxygen, said reheater combusting the hydrocarbon fuel and the oxygen to produce additional steam and CO 2  and adding the steam/CO 2  mixture from said discharge of said separator before a reheater output to produce a further heated steam/CO 2  mixture discharged from said reheater output. 
     
     
         5 . The system of  claim 3  wherein said concentrated brine outlet of said separator is coupled to a heat exchanger in heat transfer relationship with said high pressure source of water upstream of said water inlet of said gas generator. 
     
     
         6 . The system of  claim 5  wherein said high pressure source of water is produced water including non-water constituents therein. 
     
     
         7 . The system of  claim 6  wherein said source of high pressure water in the form of produced water includes fuel entrained therein, said fuel at least partially combusted in said gas generator with the hydrocarbon fuel from said source of hydrocarbon fuel and the oxygen from said high pressure source of oxygen. 
     
     
         8 . The system of  claim 7  wherein said high pressure source of water includes fuel entrained therein including associated gas as at least a portion of the fuel entrained therein, and wherein a separator is provided between said high pressure source of water and said gas generator water inlet to remove at least a portion of the associated gas from the produced water. 
     
     
         9 . The system of  claim 8  wherein said associated gas separator includes a gas outlet upstream of a fuel blender, said fuel blender located between said high pressure source of hydrocarbon fuel and said fuel inlet of said generator, said fuel blender blending at least a portion of the associated gas with the hydrocarbon fuel from said high pressure source of hydrocarbon fuel to deliver at least a portion of the associated gas with the hydrocarbon fuel to said fuel inlet of said gas generator. 
     
     
         10 . The system of  claim 8  wherein said associated gas separator also includes a liquid hydrocarbon outlet for removing liquid hydrocarbons from the produced water before routing of the produced water into said water inlet of said gas generator. 
     
     
         11 . The system of  claim 1  wherein said heat exchanger includes at least two separate heat exchangers in series along said steam/CO 2  mixture line downstream of said gas generator outlet and along said substantially pure high pressure water line, and wherein said substantially pure high pressure water line includes a feedback line between said at least two stages of heat exchangers returning a portion of the substantially pure high pressure water back to a location on said substantially pure high pressure water line preceding a first stage of said heat exchanger, such that a liquid fraction of the substantially pure high pressure water can be fed back for further heating and a higher quality of superheated steam is discharged from said heat exchanger. 
     
     
         12 . The system of  claim 11  wherein said substantially pure high pressure water line is located downstream of a pump and a condenser, said condenser located downstream of said high pressure steam/CO 2  mixture line of said heat exchanger, with said condenser including an outlet for gases including carbon dioxide and a liquid outlet for substantially pure water for supply to said pump and said substantially pure high pressure water line of said heat exchanger. 
     
     
         13 . A method for producing substantially pure high pressure steam, comprising in combination:
 providing a gas generator having a fuel inlet coupled to a high pressure source of hydrocarbon fuel, an oxidizer inlet coupled to a high pressure source of oxygen, the source of oxygen being a majority oxygen, a water inlet coupled to a high pressure source of water, said high pressure sources of oxygen, hydrocarbon fuel and water each having a pressure of at least ten times standard atmospheric pressure;   combusting the hydrocarbon fuel and the oxygen within the gas generator to produce steam and CO 2  and adding water from the water inlet of the gas generator to the produced steam and CO 2  before an outlet from said gas generator to produce a steam/CO 2  mixture;   discharging the steam/CO 2  mixture from the gas generator at a gas generator outlet; and   exchanging heat between the steam/CO 2  mixture downstream of the gas generator outlet and substantially pure high pressure water in a substantially pure high pressure water line having a pressure of at least ten times standard atmospheric pressure.   
     
     
         14 . The method of  claim 13  including the further step of separating solids from the steam/CO 2  mixture downstream of the outlet of the gas generator and before said exchanging heat step. 
     
     
         15 . The method of  claim 14  including the further step of reheating the steam/CO 2  mixture after said separating of solids step and before said exchanging heat step by routing the steam/CO 2  mixture to a reheater including an oxygen inlet coupled to said source of oxygen and a fuel inlet coupled to said source of hydrocarbon fuel and combusting the oxygen and fuel to produce additional steam and carbon dioxide and combining the created steam and carbon dioxide with the steam/CO 2  mixture and discharging a new higher temperature steam/CO 2  mixture from an output of the reheater. 
     
     
         16 . The method of  claim 14  wherein said separating of solids step includes discharging a concentrated brine from a separator interposed between the outlet of the gas generator and before said exchanging heat step, the concentrated brine exchanging heat with high pressure water from the high pressure source of water upstream of the water inlet of the gas generator. 
     
     
         17 . The method of  claim 14  wherein the high pressure source of water includes fuel entrained therein, and wherein said combusting step includes combusting fuel entrained with the water with oxygen within the gas generator. 
     
     
         18 . The method of  claim 17  including the further step of separating associated gas from the high pressure source of water upstream of the water inlet of the gas generator and routing the separated associated gas to a fuel blender between the high pressure source of hydrocarbon fuel and the fuel inlet of the gas generator for blending of at least a portion of the associated gas from the high pressure source of water with the hydrocarbon fuel from the high pressure source of hydrocarbon fuel before entry into the fuel inlet of the gas generator. 
     
     
         19 . The method of  claim 18  including the further step of separating liquid hydrocarbons from the high pressure source of water and discharging the separated liquid hydrocarbons from the system. 
     
     
         20 . The method of  claim 13  wherein said exchanging heat step includes at least two separate stages of exchanging heat between the steam/CO 2  mixture and the substantially pure high pressure water, and wherein a liquid portion of the high pressure water between the stages of exchanging heat is fed back to an upstream portion of the substantially pure high pressure water for further heating thereof in an earlier stage of the exchanging heat step. 
     
     
         21 . The method of  claim 13  including the further step of condensing the steam/CO 2  mixture after said exchanging heat step, separating at least a portion of CO 2  from the steam/CO 2  mixture, pumping a water portion of the steam/CO 2  mixture to a pressure at least ten times greater than standard atmospheric pressure and supplying the pressurized water as at least a portion of water in the substantially pure high pressure water line of said exchanging heat step.