US20050282096A1 - Maintaining oxygen/carbon ratio with temperature controlled valve - Google Patents
Maintaining oxygen/carbon ratio with temperature controlled valve Download PDFInfo
- Publication number
- US20050282096A1 US20050282096A1 US10/873,078 US87307804A US2005282096A1 US 20050282096 A1 US20050282096 A1 US 20050282096A1 US 87307804 A US87307804 A US 87307804A US 2005282096 A1 US2005282096 A1 US 2005282096A1
- Authority
- US
- United States
- Prior art keywords
- cpo
- air
- fuel
- valve
- inlet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C13/00—Apparatus in which combustion takes place in the presence of catalytic material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N1/00—Regulating fuel supply
- F23N1/02—Regulating fuel supply conjointly with air supply
- F23N1/022—Regulating fuel supply conjointly with air supply using electronic means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
- F23C2900/03002—Combustion apparatus adapted for incorporating a fuel reforming device
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K2900/00—Special features of, or arrangements for fuel supplies
- F23K2900/05001—Control or safety devices in gaseous or liquid fuel supply lines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2225/00—Measuring
- F23N2225/26—Measuring humidity
Definitions
- This invention relates to using a fuel/air ratio valve at the inlet of a catalytic partial oxidizer (CPO) to control CPO exit temperature in the presence of disturbances, such as changes in air or fuel composition or temperature.
- CPO catalytic partial oxidizer
- CPO catalytic partial oxidation
- the conversion of hydrocarbon fuel such as natural gas or propane to a hydrogen-rich gas is particularly useful to provide fuel for a fuel cell power plant.
- Catalytic partial oxidation (CPO) reactors require that the oxygen to carbon (fuel) molar ratios be maintained within a narrow range in order to maintain proper reactor operating temperatures. If the temperature of the catalyst is not maintained between about 750° C. and 850° C., the production of hydrogen falls off. Furthermore, if the temperature of the catalyst rises above about 900° C., the catalyst is damaged and production is permanently impaired.
- the composition of the fuel stream at the CPO inlet can change due to changes in the composition of an external fuel supply, or due to internal changes resulting from a hydrodesulfurization process. If humidified air is used at the inlet of the CPO, the manner of its humidification, such as from an enthalpy recovery device, can cause variations in the humidity of the air from time to time, causing lowering of oxygen partial pressure.
- Objects of the invention include: precise control of the oxygen/carbon ratio at the inlet of a CPO; controlling the fuel/air mixture at the inlet to a CPO in a manner which is insensitive to changes in the compositions of the inlet gases; improved generation of hydrogen-rich gas in a CPO; improved generation of fuel for a fuel cell power plant; and an inexpensive and accurate methodology for controlling the oxygen/carbon ratio at the inlet of a CPO.
- the temperature of the reformate generated in a CPO is utilized to control a mixing valve that determines the proportion of fuel and air at the inlet of the CPO.
- a proportional/integral controller is used to convert temperature at the outlet of the CPO into a control signal for the valve.
- signal modification may be used to accommodate the time differential of temperature sensing vs. the proportioning of the molar ratio of carbon to oxygen at the input to the CPO.
- the sole figure herein is a simplified schematic diagram of a system generating hydrogen-rich reformate for a fuel cell system employing the present invention.
- a fuel supply includes a source 6 of natural gas or liquified petroleum gas which provides fuel over a conduit 7 to a hydrodesulfurizer 8 , the output of which on a conduit 9 is provided to a proportioning mixing valve 10 which has two inlets 11 , 12 and one outlet 13 .
- the inlet 11 receives fuel from the hydrodesulfurizer 8 .
- the inlet 12 is connected by a conduit 20 through a pump 22 to an energy recovery device 21 that receives unhumidified air drawn by the pump 22 and derives heat and moisture from air in a conduit 24 at the oxidant outlet 25 of a fuel cell system 26 .
- the valve 10 provides an air/fuel mixture in a conduit 30 to a catalytic partial oxidizer 31 (CPO).
- CPO catalytic partial oxidizer
- the fuel air mixture is converted to a mixture which is, on a dry basis, essentially 37% hydrogen, 15% CO, 4% CO 2 and traces of other gases including unconverted hydrocarbons.
- This reformate is passed over a conduit 34 through a water gas shift reactor 35 which also receives water over a conduit 36 .
- the water and carbon monoxide are converted to CO 2 and hydrogen, thereby enriching the flow within a conduit 39 .
- a preferential CO oxidizer 40 converts significant amounts of the remaining CO into CO 2 , which is less innocuous to the catalyst in a fuel cell.
- the hydrogen-rich gas in a conduit 41 is passed through the anode flow fields of the fuel cell system 26 , the exhaust 27 of which may be returned in a fuel recycle loop 24 , and occasionally purged, all as is conventional, and the details of which are not critical to the present invention.
- a temperature sensor 50 provides a temperature signal on a line 51 to a controller 52 , which in turn determines, via a signal on a line 53 , the positioning of the proportioning mixing valve 10 so as to provide a substantially perfect ratio of air to fuel, as is determined by the temperature in the conduit 34 .
- the signal on the line 51 may be processed through a proportional and integral gain.
- the air in the conduit 20 may be unhumidified air, within the purview of the invention.
- the blower 22 will operate at substantially constant speed.
Abstract
Fuel from a source (6) passes through a hydrogen desulfurizer (8) and a proportioning mixing valve (10) to a CPO (31), the temperature of the output of the CPO being monitored (50) to provide a signal (51) which a controller (52) utilizes to adjust the valve (10). The output of the CPO may be passed through a water gas shift reactor (35) and a preferential CO oxidizer (40) to provide fuel to a fuel cell system (26). The air provided to the valve (10) may be humidified, such as by an enthalpy recovery device (21) receiving the oxidant outflow (24) from the fuel cell system.
Description
- This invention relates to using a fuel/air ratio valve at the inlet of a catalytic partial oxidizer (CPO) to control CPO exit temperature in the presence of disturbances, such as changes in air or fuel composition or temperature.
- The conversion of hydrocarbon fuel such as natural gas or propane to a hydrogen-rich gas is particularly useful to provide fuel for a fuel cell power plant. Catalytic partial oxidation (CPO) reactors require that the oxygen to carbon (fuel) molar ratios be maintained within a narrow range in order to maintain proper reactor operating temperatures. If the temperature of the catalyst is not maintained between about 750° C. and 850° C., the production of hydrogen falls off. Furthermore, if the temperature of the catalyst rises above about 900° C., the catalyst is damaged and production is permanently impaired.
- To maintain nominal catalyst temperature, it is necessary to carefully control the air and fuel flow rates to maintain proper molar ratios. However, the composition of the fuel stream at the CPO inlet can change due to changes in the composition of an external fuel supply, or due to internal changes resulting from a hydrodesulfurization process. If humidified air is used at the inlet of the CPO, the manner of its humidification, such as from an enthalpy recovery device, can cause variations in the humidity of the air from time to time, causing lowering of oxygen partial pressure.
- None of the prior art systems are sensitive to the varying compositions of the fuel and air. Mass flow controllers are very expensive and tend to have a high pressure drop. In having both a fuel blower and an air blower with variable speed drives, variation in the speed of either blower may disturb the rate of flow from the other blower, which can result in interaction of controls or instability.
- Objects of the invention include: precise control of the oxygen/carbon ratio at the inlet of a CPO; controlling the fuel/air mixture at the inlet to a CPO in a manner which is insensitive to changes in the compositions of the inlet gases; improved generation of hydrogen-rich gas in a CPO; improved generation of fuel for a fuel cell power plant; and an inexpensive and accurate methodology for controlling the oxygen/carbon ratio at the inlet of a CPO.
- According to the present invention, the temperature of the reformate generated in a CPO is utilized to control a mixing valve that determines the proportion of fuel and air at the inlet of the CPO. In further accord with the invention, a proportional/integral controller is used to convert temperature at the outlet of the CPO into a control signal for the valve. If desired, signal modification may be used to accommodate the time differential of temperature sensing vs. the proportioning of the molar ratio of carbon to oxygen at the input to the CPO.
- Other objects, features and advantages of the present invention will become more apparent in the light of the following detailed description of exemplary embodiments thereof, as illustrated in the accompanying drawing.
- The sole figure herein is a simplified schematic diagram of a system generating hydrogen-rich reformate for a fuel cell system employing the present invention.
- Referring to the figure, a fuel supply includes a
source 6 of natural gas or liquified petroleum gas which provides fuel over aconduit 7 to ahydrodesulfurizer 8, the output of which on aconduit 9 is provided to aproportioning mixing valve 10 which has twoinlets outlet 13. Theinlet 11 receives fuel from thehydrodesulfurizer 8. Theinlet 12 is connected by aconduit 20 through apump 22 to anenergy recovery device 21 that receives unhumidified air drawn by thepump 22 and derives heat and moisture from air in aconduit 24 at theoxidant outlet 25 of afuel cell system 26. Some of the heat and humidity in the air exhausting from the fuel cell within theconduit 24 is transferred to the air passing through theenthalpy recovery device 21, before the exhaust air passes to ambient 28. Humidified air from thepump 22 is passed in aconduit 29 to theair inlet 45 of the fuel cell system as well as in theconduit 20 to thevalve inlet 12. - The
valve 10 provides an air/fuel mixture in aconduit 30 to a catalytic partial oxidizer 31 (CPO). Therein, the fuel air mixture is converted to a mixture which is, on a dry basis, essentially 37% hydrogen, 15% CO, 4% CO2 and traces of other gases including unconverted hydrocarbons. This reformate is passed over aconduit 34 through a watergas shift reactor 35 which also receives water over aconduit 36. In the watergas shift reactor 35, the water and carbon monoxide are converted to CO2 and hydrogen, thereby enriching the flow within aconduit 39. Then, apreferential CO oxidizer 40 converts significant amounts of the remaining CO into CO2, which is less innocuous to the catalyst in a fuel cell. The hydrogen-rich gas in aconduit 41, sometimes referred to as “syngas”, is passed through the anode flow fields of thefuel cell system 26, theexhaust 27 of which may be returned in afuel recycle loop 24, and occasionally purged, all as is conventional, and the details of which are not critical to the present invention. - According to the invention, a
temperature sensor 50 provides a temperature signal on aline 51 to acontroller 52, which in turn determines, via a signal on aline 53, the positioning of theproportioning mixing valve 10 so as to provide a substantially perfect ratio of air to fuel, as is determined by the temperature in theconduit 34. In thecontroller 52, the signal on theline 51 may be processed through a proportional and integral gain. - In certain implementations of the present invention, the air in the
conduit 20 may be unhumidified air, within the purview of the invention. Typically, theblower 22 will operate at substantially constant speed. - The description with respect to the figure is exemplary merely, and indicative of a known system in which the present invention can be utilized to great advantage. The invention may be utilized in completely different systems, it sufficing that the temperature of the outflow of a CPO is utilized to control the proportions of air and fuel entering the CPO as reactants.
- Thus, although the invention has been shown and described with respect to exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without departing from the spirit and scope of the invention.
Claims (6)
1. A catalytic partial oxidizer system comprising:
a catalytic partial oxidizer having an inlet and an outlet;
a fuel supply;
a source of air;
a proportioning mixing valve having two inlets and an outlet and controllable so as to determine the proportion of gases at the respective inlets which will be provided to the outlet, one inlet being connected to said fuel supply and the other inlet being connected to said source of air, the outlet of said valve being connected to the inlet of said CPO;
a temperature sensor for providing a signal indicative of the temperature of flow at the outlet of said CPO; and
a controller responsive to said signal to control said valve and thereby control the proportions of gas at the respective inlets which are provided through said valve to said CPO.
2. A system according to claim 1 wherein:
said controller processes said signal with proportional and integral gain.
3. A system according to claim 1 wherein:
the outflow of said CPO is provided to a fuel cell system having a cathode exhaust passing through an enthalpy recovery device which comprises said source of air.
4. A system according to claim 1 wherein:
said source of air is a source of humidified air.
5. A system according to claim 1 wherein:
said fuel supply provides fuel selected from natural gas and liquified petroleum gas.
6. A system according to claim 1 wherein:
said fuel supply includes a hydrodesulfurizer.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/873,078 US20050282096A1 (en) | 2004-06-21 | 2004-06-21 | Maintaining oxygen/carbon ratio with temperature controlled valve |
PCT/US2005/020097 WO2006007319A2 (en) | 2004-06-21 | 2005-06-07 | Maintaining oxygen/carbon ratio with temperature controlled valve |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/873,078 US20050282096A1 (en) | 2004-06-21 | 2004-06-21 | Maintaining oxygen/carbon ratio with temperature controlled valve |
Publications (1)
Publication Number | Publication Date |
---|---|
US20050282096A1 true US20050282096A1 (en) | 2005-12-22 |
Family
ID=35480989
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/873,078 Abandoned US20050282096A1 (en) | 2004-06-21 | 2004-06-21 | Maintaining oxygen/carbon ratio with temperature controlled valve |
Country Status (2)
Country | Link |
---|---|
US (1) | US20050282096A1 (en) |
WO (1) | WO2006007319A2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ES2342797A1 (en) * | 2007-03-01 | 2010-07-14 | Consejo Superior De Investigaciones Cientificas | Test station for the characterization of protono exchange membrane fuel cells with h2 power supply (monocelda) with integrated electronic load (Machine-translation by Google Translate, not legally binding) |
CN108562003A (en) * | 2018-03-14 | 2018-09-21 | 广州仕伯特环境科技有限公司 | A kind of new wind turbine fresh air system of oxygen processed |
US11639476B2 (en) | 2010-07-02 | 2023-05-02 | Hyaxiom, Inc. | Steam/carbon ratio detection and control |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5637415A (en) * | 1996-08-30 | 1997-06-10 | General Motors Corporation | Controlled CO preferential oxidation |
US5915834A (en) * | 1997-06-09 | 1999-06-29 | Litton Systems, Inc. | Variable set point oxygen concentration mixer |
US6190623B1 (en) * | 1999-06-18 | 2001-02-20 | Uop Llc | Apparatus for providing a pure hydrogen stream for use with fuel cells |
US6294278B1 (en) * | 1998-12-12 | 2001-09-25 | General Motors Corporation | Combination of low and high temperature fuel cell device |
US6451466B1 (en) * | 2000-04-06 | 2002-09-17 | Utc Fuel Cells, Llc | Functional integration of multiple components for a fuel cell power plant |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004103453A (en) * | 2002-09-11 | 2004-04-02 | Nissan Motor Co Ltd | Fuel cell system |
-
2004
- 2004-06-21 US US10/873,078 patent/US20050282096A1/en not_active Abandoned
-
2005
- 2005-06-07 WO PCT/US2005/020097 patent/WO2006007319A2/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5637415A (en) * | 1996-08-30 | 1997-06-10 | General Motors Corporation | Controlled CO preferential oxidation |
US5915834A (en) * | 1997-06-09 | 1999-06-29 | Litton Systems, Inc. | Variable set point oxygen concentration mixer |
US6294278B1 (en) * | 1998-12-12 | 2001-09-25 | General Motors Corporation | Combination of low and high temperature fuel cell device |
US6190623B1 (en) * | 1999-06-18 | 2001-02-20 | Uop Llc | Apparatus for providing a pure hydrogen stream for use with fuel cells |
US6451466B1 (en) * | 2000-04-06 | 2002-09-17 | Utc Fuel Cells, Llc | Functional integration of multiple components for a fuel cell power plant |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ES2342797A1 (en) * | 2007-03-01 | 2010-07-14 | Consejo Superior De Investigaciones Cientificas | Test station for the characterization of protono exchange membrane fuel cells with h2 power supply (monocelda) with integrated electronic load (Machine-translation by Google Translate, not legally binding) |
US11639476B2 (en) | 2010-07-02 | 2023-05-02 | Hyaxiom, Inc. | Steam/carbon ratio detection and control |
CN108562003A (en) * | 2018-03-14 | 2018-09-21 | 广州仕伯特环境科技有限公司 | A kind of new wind turbine fresh air system of oxygen processed |
Also Published As
Publication number | Publication date |
---|---|
WO2006007319A2 (en) | 2006-01-19 |
WO2006007319A3 (en) | 2006-09-14 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: UTC FUEL CELLS, LLC, CONNECTICUT Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KABIR, ZAKIUL;ISOM, JOSHUA D.;YOKOSE, MASAKI M.;REEL/FRAME:015512/0726;SIGNING DATES FROM 20040616 TO 20040617 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |