US 4,930,454 A · Steam generating system

A combustor including means for catalytically combusting a fuel admixture of a non-combustible diluent and a carbonaceous fuel intimately mixed in a thermally self-extinguishing mass ratio so such combustion directly heats said diluent to produce a heated fluid, means for providing relative quantities of said carbonaceous fuel and an oxidant for such combustion, said means for catalytically combusting comprising a housing with an inlet chamber toward one end thereof and a discharge chamber toward the other end thereof, a catalyst supported within said housing between said chambers, means for mixing said admixture and said oxidant in said inlet chamber to form an inlet mixture preparatory to flow through said catalyst, a post-combustion injector for spraying a non-combustible cooling fluid with a high heat capacity into said heated fluid for cooling purpose, a cooling fluid control, a temperature sensor for said heated fluid for detecting the temperature thereof prior to injection of said cooling fluid, control means connected between said sensor and said flow control for transmitting a control signal to said control-fluid flow control to cause said flow control to adjust the flow of said cooling fluid into said discharge chamber for lowering the temperature of said working fluid to a selected temperature, and a post-injection temperature sensor for detecting the temperature of said heated fluid after injection of said cooling fluid, said control means being connected with said latter sensor and including a computer for comparing said post-injection temperature to said selected temperature and transmitting an appropriate signal to said cooling fluid flow control to adjust the flow of said cooling fluid to cool said working fluid to said selected temperature.

A catalytic combustor including a housing with an inlet chamber toward one end thereof and a discharge chamber toward the other end thereof, a catalyst supported within said housing between said chambers for combusting a fuel emulsion of a non-combustible diluent and a carbonaceous fuel mixed in a thermally self-extinguishing mass ratio so such combustion directly heats said diluent to produce a heated working fluid, means for providing substantially stoichiometric quantities of said carbonaceous fuel and an oxidant for such combustion, means for mixing said fuel emulsion and said oxidant in said inlet chamber to form a burn-mixture to pass over said catalyst for combustion, and means for preheating said burn-mixture and said means for preheating being contained within said housing, said means for providing stoichiometric quantities of said carbonaceous fuel and an oxidant including an emulsion flow control, an oxidant flow control, sensor means for said working fluid, computer means connected between said sensor means and said flow controls for receiving from said sensor means a signal representative of a sensed characteristic of said working fluid and sending at least one control signal to at least one of said controls in response thereto to vary the relative mass flow between said fuel in said emulsion and said oxidant toward substantially stoichiometric quantities.

A system for enhancing oil recovery from an oil bearing formation comprising means for producing a combustion-heated working fluid, including a mixture comprised of a non-combustible diluent and carbonaceous fuel mixed in a thermally self-extinguishing mass ratio, a source of said mixture, a catalytic combustor for combusting said fuel to thereby directly heat said diluent to produce said working fluid, said combustor being located above the surface of the oil bearing formation, means for delivering said mixture from said source to said combustor, an air compressor connected to said combustor for delivering air thereto, and means for controlling the relative mass flow of said fuel in said mixture and said air to substantially stoichiometric quantities for combustion in said combustor, said source of said mixture including a source of diluent, a source of carbonaceous fuel, an emulsifier communicating with both said diluent and carbonaceous fuel sources for mixing said diluent and said fuel together in said mass ratio, pump means for delivering relative quantities of said diluent and said fuel to said emulsifier in proportion to said mass ratio, means for injecting said working fluid into a downhole formed in the oil bearing formation to lessen the viscosity of the oil therein and thereby aid recovery of such oil from the formation, means for sealing said working fluid within the downhole, and means for placing said air in heat exchange relationship with that portion of the working fluid contained within said downhole.

A steam generating system comprising a catalytic combustor for producing steam including a housing with an inlet chamber for receiving a water-fuel mixture and oxidant and a discharge chamber from which products of combustion and steam exit the housing, a catalyst supported within said housing between said chambers for combusting the water-fuel mixture with a quantity of oxidant to produce the steam, a source of said water-fuel mixture mixed in a thermally self-extinguishing mass ratio communicating with said inlet chamber, means for delivering said mixture from said source to said inlet chamber, a source of oxidant communicating with said inlet chamber for mixing with said mixture, means for causing a quantity of said oxidant to flow into said inlet chamber, and means for controlling the relative mass flow of said mixture and said oxidant for combustion in the presence of said catalyst, said source of said mixture including a source of water, a source of carbonaceous fuel, an emulsifier for mixing said water and said fuel communicating with both said water and fuel sources, and flow control means for delivering relative quantities of said water and said fuel to said emulsifier in proportion to said mass ratio, a water injector in said discharge chamber and communicating with said water source for injecting water into the steam flowing from the catalyst to produce additional steam, and means for adjustment of the mass flow of such injected water for regulating the temperature of the total steam output of said combustor.

A steam generating system comprising a catalytic combustor for producing steam including a housing with an inlet chamber for receiving a water-fuel emulsion and air, and a discharge chamber from which products of combustion and steam exit the housing, a catalyst supported within said housing between said chambers for combusting the emulsion with a stoichiometric quantity of air to directly produce the steam;

a water source;
a carbonaceous fuel source;
an emulsifier communicating with both of said sources to produce said emulsion;
flow control means for delivering relative quantities of said water and said fuel from said sources to said emulsifier in proportions to produce said emulsion with a thermally self-extinguishing mass ratio of water to fuel;
means for delivering said emulsion from said emulsifier to said inlet chamber;
a deionizer communicating with said water source for deionizing the water before delivery thereof to said inlet chamber;
a mixer located upstream of said emulsifier and communicating with said water and fuel sources for mixing said water and said fuel in said mass ratio proportions prior to emulsification thereof;
an air compressor communicating with said inlet chamber for delivering air to mix therein with said emulsion;
and means for controlling the relative mass flow of said emulsion and said air for stoichiometric combustion in said catalyst including a sensor means for detecting stoichiometric burning, a flow controller for at least one of said emulsion and said air, and a computer connected between said sensor means and said flow controller for transmitting a signal thereto in response to the nature of the combustion sensed for said flow controller to vary the relative mass flow of said emulsion and air to obtain substantially stoichiometric quantities thereof;
said combustor including a post-combustion injector for spraying water into the steam from said catalyst for cooling purposes, an injection water flow control, a temperature sensor in said sensor means for detecting the temperature of said steam prior to injection of said water, said computer being connected between said sensor and said injection water flow control for transmitting a control signal thereto to cause said latter control to adjust the flow of said water into said discharge chamber for lowering the temperature of said steam from said catalyst to a selected temperature.

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A process for producing a heated working fluid by combusting a carbonaceous fuel in a combustor comprising the steps of:

(a) mixing the carbonaceous fuel with a non-combustible diluent to form a fuel-mixture which has a ratio of diluent to fuel that is thermally self-extinguishing,
(b) providing a substantially stoichiometric quantity of oxidant to the fuel-mixture for substantially stoichiometric combustion,
(c) catalytically combusting said fuel-mixture and oxidant to directly heat the diluent in the mixture to produce a heated working fluid comprised of the heated diluent and the products of such combustion,
wherein said diluent is water, said oxidant is air, and said working fluid includes steam,
(d) controlling the mass ratio of said burn-mixture relative to the mass of said oxidant by flowing said masses over said catalyst and,
(1) sensing a characteristic of said working fluid representative of stoichiometric combustion of said fuel-mixture, and
(2) varying the flow rate of said fuel-mixture relative to the flow rate of said oxidant in accordance with said sensed characteristic to change the ratio of relative mass flow to obtain stoichiometric quantities of oxidant and fuel prior to combustion,
(e) heating at least one of said mixture and said oxidant prior to combustion by placing a portion of the heated diluent and products of combustion into direct contact with said at least one of said mixture and said oxidant.

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A process for producing a heated working fluid by combusting a carbonaceous fuel in a combustor comprising the steps of:

(a) mixing the carbonaceous fuel with a non-combustible diluent to form a fuel-mixture which has a mass ratio of diluent to fuel that is thermally self-extinguishing,
(b) providing a substantially stoichiometric quantity of oxidant to the fuel-mixture for substantially stoichiometric combustion,
(c) catalytically combusting said fuel-mixture and oxidant to directly heat the diluent in the mixture to produce a heated working fluid comprised of the heated diluent and the products of such combustion, and
(d) controlling the mass ratio of said burn-mixture relative to the mass of said oxidant by flowing said masses over said catalyst and,
(1) sensing a characteristic of said working fluid representative of stoichiometric combustion of said fuel-mixture, and
(2) varying the flow rate of said fuel-mixture relative to the flow rate of said oxidant in accordance with said sensed characteristic to change the ratio of relative mass flow to obtain stoichiometric quantities of oxidant and fuel prior to combustion,
(e) preheating at least one of said mixture and said oxidant prior to combustion, and using a portion of heat from combustion of said fuel for preheating, and
(f) injecting a non-combustible cooling diluent with a high heat capacity into said heated working fluid in an amount dependent upon the sensed temperature of said working fluid prior to such injection which is sufficient to lower said heated working fluid temperature including said cooling fluid to a selected temperature.

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A process for producing steam by combusting a carbonaceous fuel in a combustor comprising the steps of:

(a) mixing the carbonaceous fuel with water to form a fuel-mixture which has a mass ratio of water to fuel that is thermally self-extinguishing,
(b) providing a quantity of air to the fuel-mixture for combustion,
(c) catalytically combusting said fuel-mixture and air to directly heat the water in the mixture to produce a heated fluid including steam and the heated products of such combustion,
(d) maintaining the ratio of the mass flow of said fuel-mixture relative to the mass flow of said air by,
(1) sensing the oxygen content of the fluid heated by the combustion, and
(2) varying the flow rate of said fuel-mixture relative to the flow rate of said air to change the ratio of relative mass flows thereof to obtain a specified oxygen content in said heated fluid,
(e)
(1) sensing the actual temperature of the heated fluid, and
(2) comparing said actual temperature to a predesignated maxiumum temperature and,
(3) adjusting the mass ratio of said water to said fuel to keep said actual temperature no greater than said predesignated maximum temperature by controlling the relative mass flow of said water to the mass flow of said fuel,
(4) comparing said actual temperature to a predesignated minimum temperature and,
(5) adjusting the mass ratio of said water to said fuel to keep said actual temperature no less than said predesignated minimum temperature by controlling the relative mass flow of said water to the mass flow of said fuel,
(f) providing a direct contact heat exchange between said heated fluid and one of said fluid mixture and said air for preheating,
(g) injecting water into said heated fluid in an amount dependent upon said actual temperature of said fluid prior to such injection which is sufficient to lower said actual fluid temperature to a selected temperature,
(h) sensing the temperature of said fluid after injection of said water,
(i) comparing such post injection temperature to said selected temperature, and
(j) adjusting the flow of said injection water into said heated fluid so said latter sensed temperature is approximately equal to said selected temperature.

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A method of controlling a carbonaceous fuel combustor to produce steam at a desired heat release rate with the aid of a computer, comprising:

providing said computer with a data base for control of combustion in said combustor including,
combustion temperature vs. air/fuel-mixture ratio data particular to the carbonaceous fuel in the fuel-mixture to be combusted,
information as to a range of acceptable combustion temperatures including a maximum acceptable combustion temperature, T.sub.max, and a minimum acceptable combustion temperature, T.sub.min,
delivering substantially a preselected quantity of air to the combustor,
delivering substantially a theoretical stoichiometric quantity of fuel with said preselected quantity of air to said combustor,
delivering a quantity of water with said fuel and air for combustion therein to produce steam by direct combustion heating of said water,
constantly determining the actual temperature of said steam,
comparing such actual temperature to said maximum and minimum temperatures, T.sub.max and T.sub.min, in said data base through use of said computer,
calculating with the computer an adjustment to the existing flow of said water to increase the flow of water if the outlet temperature is not less than T.sub.max, or to decrease the flow of water if the outlet temperature is not greater than T.sub.min, and
making the appropriate adjustment in the existing flow of the water to combust within said temperature range T.sub.min, T.sub.max,
constantly adjusting the flow of said fuel-mixture relative to said quantity of air so as to burn the fuel in said mixture substantially stoichiometrically,
storing in said data base the outlet temperature for the steam produced with the next previous existing flow of said fuel-mixture,
comparing the outlet temperature for the steam produced with the now existing flow of said fuel-mixture to said stored outlet temperature through use of said computer to determine whether said outlet temperature has increased or decreased,
storing in said data base the mass flow volume of said fuel-mixture for the next previous flow thereof,
comparing the now existing fuel of said fuel-mixture to said stored mass flow through use of said computer to determine whether said flow has increased or decreased,
increasing the flow of said fuel-mixture relative to said quantity of air if, said temperature comparison shows said outlet temperature has increased and said flow comparison shows the flow has increased;
or said temperature comparison shows said outlet temperature has decreased and said flow was decreased or,
decreasing the flow of said fuel-mixture relative said quantity of air if,
said temperature comparison shows said temperature has increased, and said flow comparison shows said flow has decreased, or
said temperature comparison shows said temperature has decreased and said flow comparison shows said flow was decreased.

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A method of enhanced oil recovery from an oil bearing formation with the aid of a computer to control a catalytic combustor to produce a heated discharge fluid including steam at a desired heat release rate and temperature, comprising:

providing said computer with a data base for control of combustion in said combustor including,
desired formation stimulation data including desired heat release rate, temperature data, and oxygen control for the discharge fluid for determined formation characteristics including permeability, pressure and temperature,
fuel-mixture data for the fuel-mixtures to be combusted including combustion temperature vs. air/fuel-mixture ratio data particular to the carbonaceous fuel in the fuel-mixture to be combusted,
information as to a range of acceptable combustion temperatures including minimum and maximum acceptable combustion temperatures,
initially delivering substantially theoretical stoichiometric quantities of air and fuel to said compuster at a rate so as to provide said desired heat releast rate,
initially delivering a quantity of water to the combustor at a rate so as to absorb heat from combustion of said fuel to theoretically maintain the temperature of said discharge fluid at said desired temeprature,
dividing said quantity of water between first and second portions for mixing with said fuel to form said fuel-mixture and injecting into the fluid stream heated by combustion before injection of said heated fluid into the
mixing said first portion with said fuel to form a thermally self-extinguishing burn-mixture having a catalytic adiabatic flame temperature below said maximum acceptable combustion temperature,
passing said burn-mixture over the catalyst in the combustor at a selected space velocity within a range of space velocities to combust said burn-mixture thereby directly heating the water therein,
injecting said second portion of said water into the fluid stream heated by such combustion to cool said stream theoretically to said desired discharge fluid temperature,
determining the actual operation data including combustion and discharge fluid temperatures of said fluid stream, the actual flow rates of said first and second portions of water, said air and said fuel-mixture and the oxygen content of said heated fluid stream,
providing said computer with said actual operation data,
comparing with said computer the actual operation data with said desired heat release rate, said desired discharge temperature, desired combustion temperature range and desired oxygen content,
continually determining with said computer adjustments needed in the actual flow rates of said fuel-mixture, said air and said first and second portions of water through said combustor to adjust said actual flow rates to achieve said desired heat release rate, a combustion temperature within said desired combustion temperature range and said desired oxygen content, and
adjusting said actual flow rates accordingly.

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A combustor:

comprising,
means for catalytically combusting a fuel admixture of a non-combustible diluent and a carbonaceous fuel intimately mixed in a thermally self-extinguishing mass ratio so such combustion directly heats said diluent to produce a heated fluid;
means for providing relative quantities of said carbonaceous fuel and an oxidant for such combustion;
said means for catalytically combusting comprising a housing with an inlet chamber toward one end thereof and a discharge chamber toward the other end thereof, a catalyst supported within said housing between said chambers, means for mixing said admixture and said oxidant in said inlet chamber to form an inlet mixture preparatory to flow through said catalyst;
said combustor further comprising means for preheating said inlet mixture which includes a device supported within said housing for conducting a portion of the heat of combustion of said inlet mixture to said admixture and said oxidant with said device including a heat-conducting passage connected between said discharge chamber and said inlet chamber for a portion of the products of combustion to flow from said discharge chamber into said inlet chamber for direct preheating of said inlet mixture.

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A downhole steam generator comprising means for catalytically combusting an emulsion comprised of water and carbonaceous fuel mixed in a thermally self-extinguishing mass ratio so catalytic combustion of the fuel directly heats the water to produce steam, means for providing substantially stoichiometric quantities of the fuel and air for such combustion, said means for catalytically combusting including a housing with an inlet chamber toward one end thereof and a discharge chamber toward the other end thereof, and a catalyst supported within said housing between said chambers, said emulsion and air being received within said inlet chamber to form an inlet mixture for combustion in the presence of said catalyst;

said means for providing stoichiometric quantities of said fuel and emulsion including an emulsion flow control, sensor means for said steam, computer means connected between said sensor means and said emulsion flow control for receiving from said sensor means a signal representative of a sensed characteristic of said steam and sending a control signal to said emulsion flow control in response thereto to vary the flow of said emulsion to obtain a substantially stoichiometric amount thereof relative to said air;
said downhole steam generator including a device supported within said housing for conducting a portion of the heat of combustion of said inlet mixture into direct contract with said emulsion and said air.

A downhole steam generator comprising means for catalytically combusting an emulsion comprised of water and carbonaceous fuel mixed in a thermally self-extinguishing mass ratio so catalytic combustion of the fuel directly heats the water to produce steam, means for providing substantially stoichiometric quantities of the fuel and air for such combustion, said means for catalytically combusting including a housing with an inlet chamber toward one end thereof and a discharge chamber toward the other end thereof, and a catalyst supported within said housing between said chambers, said emulsion and air being received within said inlet chamber to form an inlet mixture for combustion in the presence of said catalyst;

said means for providing stoichiometric quantities of said fuel and air includes an air flow control, sensor means for said steam, computer means connected between said sensor means and said air flow control for receiving from said sensor means a signal representative of sensed characteristic of said steam and sending a control signal to said air flow control in response thereto to vary the flow of said air to obtain a substantially stoichiometric amount thereof relative to said fuel;
said downhole steam generator further including means for directly heating said emulsion and air which includes a device supported within said housing for conducting a portion of the heat of combustion of said fuel and air to said emulsion and air with said device including a heat conducting passage connected between said discharge chamber and said inlet chamber for a portion of the products of combustion to flow from said discharge chamber into said inlet chamber for preheating said emulsion and air.

A downhole steam generator comprising means for catalytically combusting an emulsion comprised of water and carbonaceous fuel mixed in a thermally self-extinguishing mass ratio so catalytic combustion of the fuel directly heats the water to produce steam, means for providing substantially stoichiometric quantities of the fuel and air for such combustion, said means for catalytically combusting including a housing with an inlet chamber toward one end thereof and a discharge chamber toward the other end thereof, and a catalyst supported within said housing between said chambers, said emulsion and air being received within said inlet chamber to form an inlet mixture for combustion in the presence of said catalyst;

said downhole steam generator further including means for directly heating said emulsion and air which includes a device supported within said housing for conducting a portion of the heat of combustion of said fuel and air to said emulsion and air with said device including a heat conducting passage connected between said discharge chamber and said inlet chamber for a portion of the products of combustion to flow from said discharge chamber into said inlet chamber for direct preheating of said emulsion and air.

A downhole steam generator comprising means for catalytically combusting an emulsion comprised of water and carbonaceous fuel mixed in a thermally self-extinguishing mass ratio so catalytic combustion of the fuel directly heats the water to produce steam, means for providing substantially stoichiometric quantities of the fuel and air for such combustion, said means for catalytically combusting including a housing with an inlet chamber toward one end thereof and a discharge chamber toward the other end thereof, and a catalyst supported within said housing between said chambers, said emulsion and air being received within said inlet chamber to form an inlet mixture for combustion in the presence of said catalyst;

said means for providing stoichiometric quantities of said fuel and air including an emulsion flow control, an air flow control, sensor means for said steam, and computer means connected between said sensor means and said flow controls for receiving from said sensor means a signal representative of a sensed characteristic of said steam and sending at least one control signal to at least one of said flow controls in response thereto to vary the relative mass flow between said emulsion and said air to obtain substantially stoichiometric quantity thereof;
and
said downhole steam generator further including means for directly heating said emulsion and air which includes a device supported within said housing for conducting a portion of the heat of combustion of said fuel and air to said emulsion and air with said device including a heat conducting passage connected between said discharge chamber and said inlet chamber for a portion of the products of combustion to flow from said discharge chamber into said inlet chamber for preheating said emulsion and air.

A process for producing a heated working fluid by combusting a carbonaceous fuel in a combustor comprising the steps of:

(a) mixing the carbonaceous fuel with a noncombustible diluent to form a fuel-mixture which has a mass ratio of diluent to fuel that is thermally self-extinguishing,
(b) providing a substantially stoichiometric quantity of oxidant to the fuel-mixture for substantially stoichiometric combustion,
(c) catalytically combusting said fuel-mixture and oxidant to directly heat the diluent in the mixture to produce a heated working fluid comprised of the heated diluent and the products of such combustion, and
(d) controlling the mass ratio of said burn-mixture relative to the mass of said oxidant by flowing said masses over said catalyst and,
(1) sensing a characteristic of said working fluid representative of stoichiometric combustion of said fuel-mixture, and
(2) varying the flow rate of said fuel-mixture relative to the flow rate of said oxidant in accordance with said sensed characteristic to change the ratio of relative mass flow to obtain stoichiometric quantities of oxidant and fuel prior to combustion,
(3) comparing first and second time spaced temperatures of said heated working fluid,
(4) comparing a first ratio of relative mass flows of a mixture to oxidant which results in production of said working fluid at said first temperature, against a second ratio of relative mass flows of said working fluid at said second temperature, and increasing the relative mass flow of said mixture to said oxidant if, said second ratio is greater than said first ratio and said second temperature is greater than said first temperature, or if, said second ratio is less than said first ratio and said second temperature is less than said first temperature, or,
decreasing the relative mass flow of said mixture to said oxidant if, said second ratio is less than said first ratio and said second temperature is greater than said first temperature, or if, said second ratio is greater than said first ratio and said second temperature is less than said first temperature.

6 more elements

Steam generating system

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Steam generating system

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Abstract

Claims80