An SOFC power generation system with out-band reforming

Abstract

The application discloses a SOFC power generation system with external reforming, which comprises a SOFC stack; the SOFC stack inlet is connected with a gas outlet of a reforming reaction component; a raw material gas inlet of the reforming reaction component is connected with an outlet of a static mixer; an inlet of the static mixer is connected with an outlet of an ejector; an inlet of the ejector is connected with an outlet of a steam drum; an inlet of the steam drum is connected with an outlet of an evaporator; an inlet of the evaporator is connected with a water supply system; an entraining inlet of the ejector is connected with a diesel steam supply system; a pressure sensor is arranged in the evaporator; the pressure sensor is connected with a controller; the controller is connected with a heating pipe in the evaporator. The application adjusts the flow ratio of water vapor and diesel steam by adjusting the pressure of water vapor entering the ejector according to the principle of the ejector, so that the flow of water vapor and diesel steam entering the ejector is maintained stable when the pressure of water vapor entering the ejector is stable, thereby effectively controlling the water-carbon ratio of water vapor and diesel to be stable.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen production by reforming of hydrocarbon fuel, and particularly relates to a SOFC power generation system with external reforming. BACKGROUND

[0002] Solid oxide fuel cell (SOFC) is a kind of full solid chemical power generation device which can convert chemical energy stored in fuel and oxidant into electric energy efficiently and environmentally friendly at medium-high temperature. Different from proton exchange membrane fuel cell (PEMFC), SOFC fuel is adaptable and can accept hydrogen-rich gas containing hydrocarbon and carbon monoxide as fuel, so the SOFC system can use natural gas, diesel and the like to generate hydrogen-rich gas for entering the SOFC cell to generate power after external reforming.

[0003] Compared with natural gas, diesel is a liquid fuel, which is more secure, more convenient to transport and store, and has larger volume energy density, so the diesel reforming hydrogen production technology is widely used in the SOFC power generation system.

[0004] When diesel is reformed to produce hydrogen, diesel and water vapor are mixed at a stable water-carbon ratio and then enter the reforming reactor to avoid carbon deposition poisoning of the reforming catalyst at high temperature. In the conventional diesel reforming SOFC power generation system, a metering pump is used to control the flow of liquid diesel and liquid water at room temperature to realize the control of the water-carbon ratio. However, this method cannot control the vaporization degree in the evaporator, so it is difficult to accurately control the water vapor flow and to realize the continuous and stable proportion of diesel and water vapor.

[0005] Based on the above problems, the application provides a SOFC power generation system with external reforming, which adjusts the flow ratio of water vapor and diesel vapor by adjusting the pressure of water vapor entering the injector according to the principle of the injector, and when the pressure of water vapor entering the injector is stable, the flow of water vapor and diesel vapor entering the injector is also stable, so as to effectively control the water-carbon ratio of water vapor and diesel. SUMMARY

[0006] The application aims to overcome the shortcomings of the prior art and provide a SOFC power generation system with external reforming.

[0007] To achieve the above purpose, the application adopts the following technical scheme:

[0008] A SOFC power generation system with external reforming comprises a SOFC stack.

[0009] The inlet of the SOFC stack is connected with the gas outlet of the reforming reaction assembly, the raw gas inlet of the reforming reaction assembly is connected with the outlet of the static mixer, the inlet of the static mixer is connected with the outlet of the ejector;

[0010] The inlet of the ejector is connected with the outlet of the steam drum, the inlet of the steam drum is connected with the outlet of the evaporator, the inlet of the evaporator is connected with the water supply system;

[0011] The entraining inlet of the ejector is connected with the diesel vapor supply system;

[0012] The pressure sensor is arranged in the evaporator, the pressure sensor is connected with the controller, and the controller is connected with the heating pipe in the evaporator.

[0013] Preferably, the water supply system comprises a water tank, the outlet of the water tank is connected with the inlet of the water pump, and the outlet of the water pump is connected with the inlet of the evaporator.

[0014] Preferably, the diesel vapor supply system comprises a diesel oil tank, the outlet of the diesel oil tank is connected with the inlet of the diesel pump, the outlet of the diesel pump is connected with the inlet of the diesel desulfurizer, the outlet of the diesel desulfurizer is connected with the inlet of the diesel evaporator, and the outlet of the diesel evaporator is connected with the entraining inlet of the ejector.

[0015] Preferably, a pressure regulating valve is arranged on the pipeline between the steam drum and the ejector.

[0016] Preferably, the reforming reaction assembly comprises a plate preheater and a reforming reactor.

[0017] The mixed gas inlet of the plate preheater is connected with the outlet of the static mixer, the mixed gas outlet of the plate preheater is connected with the cold channel inlet of the reforming reactor, and the cold channel outlet of the reforming reactor is connected with the inlet of the SOFC stack.

[0018] The hot channel inlet of the reforming reactor is connected with the heat source supply system, the hot channel outlet of the reforming reactor is connected with the heat source channel inlet of the plate preheater, and the heat source channel outlet of the plate preheater is connected with the exhaust pipeline.

[0019] Preferably, the heat source supply system comprises a combustion tank and an air compressor.

[0020] The anode tail gas outlet of the SOFC stack and the outlet of the air compressor are both connected with the inner cavity of the combustion tank.

[0021] The outlet of the combustion tank is connected with the hot channel inlet of the reforming reactor.

[0022] Preferably, a thermocouple is arranged in the cold channel and the hot channel of the reforming reactor.

[0023] Preferably, the reforming reactor comprises a pillow plate heat exchanger body, an inner wall surface of a cold channel in the pillow plate heat exchanger body being coated with a catalyst for diesel reforming reaction.

[0024] The present application has the following beneficial effects:

[0025] (1) The present application adjusts the flow ratio of water vapor and diesel vapor by adjusting the pressure of water vapor entering the injector according to the principle of the injector, and when the pressure of water vapor entering the injector is stable, the flow of water vapor and diesel vapor entering the injector is also stable, thereby effectively controlling the water-carbon ratio of water vapor and diesel to be stable.

[0026] (2) The pillow plate heat exchanger is used as the body structure of the reforming reactor in the present application, based on the high heat transfer efficiency characteristics of the pillow plate heat exchanger, combined with the setting of the thermocouple, the temperature control in the reforming reactor can be realized, and the carbon deposition reaction caused by too high temperature or the reduction of reforming efficiency caused by too low temperature can be avoided. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which form a part of the present application, are included to provide further understanding of the present application, and serve to explain the principle of the illustrative embodiments of the present application and their description, and shall not constitute improper limitations to the present application.

[0028] Figure 1 is a flow diagram of the out-of-band reforming SOFC power generation system of the present application;

[0029] Figure 2 is a structural diagram of the evaporator in the present application;

[0030] Wherein: 1- water tank, 2- water pump, 3- evaporator, 301- heating pipe, 302- pressure sensor, 303- controller, 4- steam drum, 5- pressure regulating valve, 6- injector, 7- diesel oil tank, 8- diesel pump, 9- diesel desulfurizer, 10- diesel evaporator, 11- static mixer, 12- plate preheater, 13- reforming reactor, 14- SOFC stack, 15- combustion tank, 16- air compressor. DETAILED DESCRIPTION

[0031] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0032] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0033] In this invention, terms such as "upper," "lower," "bottom," and "top" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are merely relational terms determined for the convenience of describing the structural relationship of the various components or elements of this invention, and do not specifically refer to any component or element in this invention, and should not be construed as limiting this invention.

[0034] In this invention, terms such as "connected" and "linked" should be interpreted broadly, indicating a fixed connection, an integrated connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] like Figure 1 As shown, an SOFC power generation system with out-of-band reforming includes an SOFC stack 14.

[0037] The inlet of the SOFC stack 14 is connected to the gas outlet of the reforming reaction assembly, the feed gas inlet of the reforming reaction assembly is connected to the outlet of the static mixer 11, and the inlet of the static mixer 11 is connected to the outlet of the ejector 6.

[0038] The inlet of the injector 6 is connected to the outlet of the steam drum 4, the inlet of the steam drum 4 is connected to the outlet of the evaporator 3, and the inlet of the evaporator 3 is connected to the water supply system.

[0039] The ejector inlet of the injector 6 is connected to the diesel vapor supply system;

[0040] like Figure 2As shown, a pressure sensor 302 is arranged in the evaporator 3, the pressure sensor 302 is connected with a controller 303, the controller 303 is connected with the heating pipe 301 in the evaporator 3, the controller 303 controls the heating efficiency of the heating pipe 304 in the evaporator 3 according to the pressure in the evaporator 3 detected by the pressure sensor 302, so as to ensure the stability of the pressure in the evaporator 3. The water vapor from the steam drum 4 enters the ejector 6, the flow rate of the water vapor and the diesel vapor is adjusted by adjusting the pressure of the water vapor entering the ejector 6 according to the principle of the ejector, and the stability of the pressure of the water vapor entering the ejector 6 can be ensured by the stability of the pressure in the evaporator 3, so that the flow rate of the water vapor and the diesel vapor entering the ejector is also maintained stable, thereby effectively controlling the stability of the water-carbon ratio of the water vapor and the diesel vapor. In addition, the diesel vapor and the water vapor are preliminarily mixed in the ejector 6, and then pass through the static mixer 11, so as to ensure that the diesel vapor and the water vapor are uniformly mixed, and the carbon deposition on the reforming catalyst is reduced.

[0041] Preferably, the water supply system comprises a water tank 1, the outlet of the water tank 1 is connected with the inlet of the water pump 2, and the outlet of the water pump 2 is connected with the inlet of the evaporator 3.

[0042] Preferably, the diesel vapor supply system comprises a diesel tank 7, the outlet of the diesel tank 7 is connected with the inlet of the diesel pump 8, the outlet of the diesel pump 8 is connected with the inlet of the diesel desulfurizer 9, the outlet of the diesel desulfurizer 9 is connected with the inlet of the diesel evaporator 10, and the outlet of the diesel evaporator 10 is connected with the inlet of the ejector 6.

[0043] The diesel contains a small amount of sulfide, which can cause poisoning of the reforming catalyst and the fuel cell catalyst, so the diesel is desulfurized by the diesel desulfurizer 9 before entering the reactor, and the desulfurized diesel is gasified by the diesel evaporator 10.

[0044] Preferably, a pressure regulating valve 5 is arranged on the pipeline between the steam drum 4 and the ejector 6.

[0045] Preferably, the reforming reaction assembly comprises a plate preheater 12 and a reforming reactor 13.

[0046] The mixed gas inlet of the plate preheater 12 is connected with the outlet of the static mixer 11, the mixed gas outlet of the plate preheater 12 is connected with the cold channel inlet of the reforming reactor 13, and the cold channel outlet of the reforming reactor 13 is connected with the inlet of the SOFC stack 14.

[0047] The hot channel inlet of the reforming reactor 13 is connected with the heat source supply system, the hot channel outlet of the reforming reactor 13 is connected with the heat source channel inlet of the plate preheater 12, and the heat source channel outlet of the plate preheater 12 is connected with the exhaust pipeline.

[0048] Preferably, the heat source supply system comprises a combustion tank 15, an air compressor 16;

[0049] The anode tail gas outlet of the SOFC stack 14 and the outlet of the air compressor 16 are both communicated to the inner cavity of the combustion tank 15;

[0050] The outlet of the combustion tank 15 is connected to the hot channel inlet of the reforming reactor 13.

[0051] In the present application, the combustion tank 15 is connected to the anode tail gas outlet of the SOFC stack 14, and the anode tail gas of the SOFC stack 14 contains a small amount of small molecule combustible gases such as alkanes, alkenes and hydrogen. The temperature of the anode tail gas from the SOFC stack 14 is about 650-750℃, and after entering the combustion tank 15, the oxidation reaction occurs under the action of the air provided by the air compressor 16, and heat is released; the gas after the reaction carries heat into the hot channel of the reforming reactor 13 to provide heat for diesel reforming, and then continues to enter the plate preheater 12 to preheat the mixed gas, so as to ensure the reaction temperature entering the reforming reactor 13.

[0052] Preferably, the reforming reactor 13 is provided with thermocouples in the cold channel and the hot channel to measure the temperature of the fluid in the channel. The temperature in the hot channel of the reforming reactor 13 is adjusted by controlling the amount of air entering the combustion tank 15 to meet the requirements of the reforming reaction in the cold channel.

[0053] Preferably, the reforming reactor 13 comprises a pillow-shaped plate heat exchanger body, and the inner wall surface of the cold channel of the pillow-shaped plate heat exchanger body is coated with a catalyst for diesel reforming reaction.

[0054] Specifically, the pillow-shaped plate heat exchanger body in the present application is a prior art, and its specific structure will not be described here. The cold and hot channels in the pillow-shaped plate heat exchanger body are concave-convex, and the fluid in the channel forms a complex turbulent flow, which strengthens the heat exchange of the fluid in the cold and hot channels, so as to timely transfer heat to the reforming reaction, avoid the occurrence of coking reaction caused by local overheating, or the decrease of reforming efficiency caused by local overcooling; the diesel vapor and water vapor react in the cold channel of the pillow-shaped plate heat exchanger body under the catalysis of the catalyst, and the concave-convex shape of the internal plate surface of the pillow-shaped plate heat exchanger body forms a complex turbulent flow and spiral flow, which can timely remove the small carbon black particles generated by the reaction, and avoid the blockage of the reactor; in addition, the concave-convex shape of the internal plate surface of the pillow-shaped plate heat exchanger body can absorb the deformation caused by the temperature difference between cold and hot, eliminate thermal stress, avoid local rupture caused by temperature difference stress, and prolong the service life of the reformer.

[0055] In addition, the pillow-shaped plate heat exchanger is used as the body structure of the reforming reactor in the present application, and based on the high heat transfer efficiency of the pillow-shaped plate heat exchanger and the arrangement of the thermocouple, the temperature control in the reforming reactor can be realized, and the carbon deposition reaction caused by excessively high temperature or the reduction of reforming efficiency caused by excessively low temperature can be avoided.

[0056] Specifically, the coating of the catalyst is realized by using the prior art, and the specific coating process is not described herein again; in the present application, the catalyst for the diesel reforming reaction is a commercial rhodium-based hydrocarbon steam conversion catalyst or a commercial nickel-based hydrocarbon steam conversion catalyst, wherein the commercial rhodium-based hydrocarbon steam conversion catalyst and the commercial nickel-based hydrocarbon steam conversion catalyst are both prior art.

[0057] The hot channel of the reforming reactor 13 is the hot channel of the body of the pillow-shaped plate heat exchanger, and the cold channel of the reforming reactor 13 is the cold channel of the body of the pillow-shaped plate heat exchanger.

[0058] In the present application, the saturated water vapor pressure entering the ejector 6 is adjusted by adjusting the pressure of the evaporator 3, and then the water-carbon ratio entering the reforming reactor 13 is adjusted, so that the effect of stably adjusting the water-carbon ratio is achieved. In addition, the mixed gas from the ejector 6 has a certain pressure, so that no additional power equipment is needed to increase the pressure.

[0059] In the specific implementation of the SOFC power generation system with external reforming, deionized water enters the evaporator 3 to generate steam with a certain pressure, and the steam flows out of the evaporator 3 and enters the steam drum 4 for steam-water separation. Then, the water vapor enters the ejector 6, and the water vapor flows at a high speed in the ejector 6 to form a low-pressure area, so as to inject the diesel vapor into the ejector 6 for preliminary mixing. The mixed gas enters the static mixer 11 for further mixing, and then the mixed water vapor and diesel vapor enter the reforming reaction assembly, which includes a plate-type preheater 12 and a reforming reactor 13. The mixed gas enters the plate-type preheater 12 for preheating, and then enters the reforming reactor 13 for reforming. The hydrogen-rich gas after reforming enters the SOFC stack 14 for reaction.

[0060] The above describes the specific embodiments of the present application in combination with the drawings, but is not a limitation of the present application. Those skilled in the art should understand that various modifications or changes made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. A SOFC power generation system with external reforming, comprising an SOFC stack; characterized in that, The inlet of the SOFC stack is connected to the gas outlet of the reforming reaction assembly, the feed gas inlet of the reforming reaction assembly is connected to the outlet of the static mixer, and the inlet of the static mixer is connected to the outlet of the ejector. The inlet of the injector is connected to the outlet of the steam drum, the inlet of the steam drum is connected to the outlet of the evaporator, and the inlet of the evaporator is connected to the water supply system. The injector's inlet is connected to the diesel vapor supply system; A pressure sensor is installed inside the evaporator, and the pressure sensor is connected to a controller, which is connected to a heating element inside the evaporator.

2. The SOFC power generation system with out-of-band reforming as described in claim 1, characterized in that, The water supply system includes a water tank, the outlet of which is connected to the inlet of a water pump, and the outlet of the water pump is connected to the inlet of an evaporator.

3. The SOFC power generation system with out-of-band reforming as described in claim 1, characterized in that, The diesel vapor supply system includes a diesel oil tank, the outlet of which is connected to the inlet of a diesel pump, the outlet of which is connected to the inlet of a diesel desulfurizer, the outlet of which is connected to the inlet of a diesel evaporator, and the outlet of which is connected to the ejector inlet of an injector.

4. The SOFC power generation system with out-of-band reforming as described in claim 1, characterized in that, A pressure regulating valve is installed on the pipeline between the steam drum and the injector.

5. The SOFC power generation system with out-of-band reforming as described in claim 1, characterized in that, The reforming reaction assembly includes a plate preheater and a reforming reactor. The mixed gas inlet of the plate preheater is connected to the outlet of the static mixer, the mixed gas outlet of the plate preheater is connected to the cold aisle inlet of the reforming reactor, and the cold aisle outlet of the reforming reactor is connected to the inlet of the SOFC stack. The inlet of the reforming reactor's hot channel is connected to the heat source supply system, the outlet of the reforming reactor's hot channel is connected to the inlet of the plate preheater's hot channel, and the outlet of the plate preheater's hot channel is connected to the discharge pipe.

6. The SOFC power generation system with out-of-band reforming as described in claim 5, characterized in that, The heat source supply system includes a combustion tank and an air compressor; The anode exhaust gas outlet and the air compressor outlet of the SOFC stack are both connected to the inner cavity of the combustion tank. The outlet of the combustion tank is connected to the inlet of the hot channel of the reforming reactor.

7. The SOFC power generation system with out-of-band reforming as described in claim 5, characterized in that, Thermocouples are installed in both the cold and hot channels of the reforming reactor.

8. The SOFC power generation system with out-of-band reforming as described in claim 5, characterized in that, The reforming reactor includes a pillow-shaped plate heat exchanger body, wherein the inner wall surface of the cold channel in the pillow-shaped plate heat exchanger body is coated with a catalyst for diesel reforming reaction.

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