Solar and biogas driven sofc multi-generation system and method

Abstract

The application provides a solar and biogas driven SOFC poly-generation system and method, a heat storage tank of a trough type solar heat collector is communicated with a first heat exchanger in an organic Rankine cycle module, so that working medium in the heat storage tank heats working medium in the organic Rankine cycle module; the first heat exchanger is communicated with a second heat exchanger in an anaerobic digestion module, so that low-temperature working medium drives an anaerobic reaction tank, the second heat exchanger is communicated with a liquid storage tank of the trough type solar heat collector; a CH4 storage tank of the anaerobic digestion module is communicated with a fuel compressor of an SOFC module, and an exhaust gas output pipeline of the SOFC module is communicated with a regenerative steam generator of a Kalina cycle module, so that exhaust gas of the SOFC module drives the Kalina cycle module to generate power; the application couples PTSC with ORC, anaerobic digestion, SOFC and KC, realizes heat and power cogeneration, realizes the renewable nature of input end energy, guarantees high poly-generation efficiency and power generation efficiency, and has the effect of energy saving and consumption reduction.

Description

Technical Field

[0001] This invention relates to the field of combined energy supply system technology, and particularly to a solar and biogas driven SOFC combined energy supply system and method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] In recent years, the amount of municipal solid waste (MSW) generated during daily operations has increased dramatically, making the scientific treatment and recycling of MSW a significant challenge. MSW is generally disposed of primarily through sanitary landfill or incineration for power generation; however, sanitary landfill or incineration often causes secondary pollution of water and soil resources, resulting in high costs for MSW treatment.

[0004] The inventors discovered that compared to conventional methods of treating municipal solid waste, anaerobic digestion (AD) offers advantages such as low cost and environmental friendliness. The biogas produced from AD can be used as fuel or for power generation, and the byproducts can be further processed into fertilizer. However, the efficiency of AD is affected by the feed temperature, which should generally be maintained between 50℃ and 55℃. Since bacterial activity during AD is greatly influenced by seasonal climate and temperature variations, traditional AD is discontinuous and unstable, and conventional power supply methods often fail to achieve precise control. Furthermore, currently, AD lacks integrated control with other systems, such as solid oxide fuel cells (SOFC), organic Rankine cycles (ORC), Kalina cycles, and parabolic trough solar collectors (PTSC), preventing multi-system co-generation and resulting in energy waste in each system, hindering comprehensive energy utilization. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a solar and biogas-driven SOFC combined heat and power system and method, which couples PTSC with ORC, anaerobic digestion, SOFC, and KC. This achieves combined heat and power generation while ensuring the renewable nature of the input energy, and simultaneously guarantees high combined heat and power efficiency and power generation efficiency, resulting in energy saving and consumption reduction.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a solar and biogas-driven SOFC (Solar-Powered Combined Heat and Power) system.

[0008] A solar and biogas-driven SOFC (Solar-Fired Combined Heat and Power) system, comprising:

[0009] Parabolic trough solar collectors, organic Rankine cycle modules, anaerobic digestion modules, SOFC modules, and Karina cycle modules;

[0010] The heat storage tank of the parabolic trough solar collector is connected to the first heat exchanger in the organic Rankine cycle module so that the working fluid in the heat storage tank heats the working fluid in the organic Rankine cycle module.

[0011] The first heat exchanger is connected to the second heat exchanger in the anaerobic digestion module so that the low-temperature working fluid drives the anaerobic reaction tank. The second heat exchanger is connected to the storage tank of the trough solar collector.

[0012] The CH4 storage tank of the anaerobic digestion module is connected to the fuel compressor of the SOFC module, and the exhaust gas output pipeline of the SOFC module is connected to the regenerative steam generator of the Karina cycle module, so that the exhaust gas of the SOFC module drives the Karina cycle module to generate electricity.

[0013] As an optional implementation, Therminol-66 is used as the working fluid in the heat storage tank and liquid storage tank terminals of the trough solar collector.

[0014] As an optional implementation, the working fluid in the organic Rankine cycle module is n-octane.

[0015] As an optional implementation, in the anaerobic digestion module and the SOFC module:

[0016] The anaerobic digester is connected to the second heat exchanger, the anaerobic digester is connected to the degassing device, the degassing device is connected to the CH4 storage tank, the CH4 storage tank is connected to the fuel compressor, the fuel compressor is connected to the fuel preheater, and the fuel preheater is connected to the second mixer.

[0017] The water pump is connected to the water preheater, which is in turn connected to the air preheater and the second mixer.

[0018] The air compressor is connected to the air preheater, which is also connected to the SOFC cathode, the water preheater, and the regenerative steam generator of the Karina cycle module.

[0019] The second mixer is connected to the SOFC anode, and the SOFC anode and SOFC cathode are respectively connected to the combustion chamber, which is connected to the fuel preheater.

[0020] As an optional implementation, in the organic Rankine cycle module:

[0021] The first heat exchanger is connected to the first turbine. The working fluid output from the first turbine is reheated and condensed, then pressurized by a pump and returned to the first heat exchanger.

[0022] As an optional implementation, in the Karina loop module:

[0023] The regenerative steam generator is connected to the separator. The first output of the separator is connected to the second turbine, and the second turbine is connected to the first mixer. The first output is ammonia-rich steam. The second output of the separator is connected to the first mixer through a throttle valve. The second output is a weak ammonia solution.

[0024] The mixed ammonia water output from the first mixer is returned to the regenerating steam generator after condensation and pressurization.

[0025] A second aspect of the present invention provides a method for SOFC (Solar-Powered Combined Heat and Power) power generation driven by solar energy and biogas.

[0026] A solar and biogas-driven SOFC (Solar-Fired Combined Heat and Power) method includes the following processes:

[0027] The working fluid in the storage tank of the parabolic trough solar collector heats the working fluid in the organic Rankine cycle module after flowing through the first heat exchanger.

[0028] The low-temperature working fluid flowing out of the first heat exchanger enters the second heat exchanger to drive the anaerobic reaction tank.

[0029] The exhaust gas from the SOFC module is fed into the regenerative steam generator of the Karina cycle module, which drives the Karina cycle module to generate electricity.

[0030] As an optional implementation method, biogas is produced in the anaerobic digester, and the biogas is degassed to remove impurities and separate methane for use as fuel.

[0031] Air is compressed by an air compressor and preheated by exhaust gas in a water preheater in an air preheater. Methane is pressurized by a fuel compressor and preheated in a fuel preheater. Water is pressurized by a water pump and preheated in a water preheater.

[0032] Preheated steam and preheated fuel are mixed in a second mixer, and the resulting mixture eventually enters the SOFC anode, while preheated air is sent to the SOFC cathode.

[0033] Air and the mixture undergo an electrochemical reaction in the SOFC fuel cell to generate electricity. The outlet gas from the SOFC anode and SOFC cathode enters the combustion chamber and is completely combusted. The combustion gas from the combustion chamber enters the fuel preheater to preheat the methane.

[0034] The exhaust gas from the air preheater enters the regenerative steam generator to drive the Karina cycle power generation, and finally the exhaust gas is released into the environment.

[0035] As an optional implementation, the working fluid in the Karina cycle module is heated into a steam-water mixture in a regenerative steam generator, and then separated into ammonia-rich vapor and a weak ammonia solution by a separator. The ammonia-rich vapor enters the second turbine to generate electricity, and then mixes with the throttled weak ammonia solution in the first mixer. The mixed ammonia water is condensed and pressurized before returning to the regenerative steam generator to complete the cycle.

[0036] As an alternative implementation, the working fluid in the organic Rankine cycle is heated to high-temperature, high-pressure steam in the first heat exchanger. The steam then enters the first turbine to generate electricity. After reheating and condensation throttling, the working fluid is pressurized to high pressure by a pump and then returns to the first heat exchanger to complete the cycle.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] 1. The solar and biogas-driven SOFC combined heat and power system and method described in this invention couples PTSC with ORC, anaerobic digestion, SOFC and KC, achieving both combined heat and power generation and renewable energy at the input end, while ensuring high combined heat and power efficiency and power generation efficiency, thus achieving energy saving and consumption reduction effects.

[0039] 2. The solar and biogas-driven SOFC combined heat and power system and method described in this invention turn urban domestic waste into a valuable resource. By utilizing the advantages of low cost and environmental friendliness of anaerobic digestion, biogas generated from urban domestic waste is used to power high-temperature fuel cells. At the same time, by-products can be processed into fertilizer, thus alleviating potential regional power shortages while achieving environmental protection.

[0040] 3. The solar and biogas-driven SOFC combined heat and power system and method described in this invention greatly reduces the impact of temperature on anaerobic digestion efficiency. By introducing PTSC, a continuous and stable supply of heat load to the anaerobic digester is achieved, improving anaerobic digestion efficiency. At the same time, the high-temperature side of the PTSC working fluid provides a heat source for the organic Rankine cycle, realizing the cascade utilization of solar energy.

[0041] 4. The solar and biogas-driven SOFC combined heat and power system and method described in this invention are green and low-carbon, in line with future development trends; the new combined heat and power system inputs solar and biomass energy, all of which are renewable energy sources, greatly reducing the use of chemical energy, and achieving overall low-carbon and environmentally friendly system, which is conducive to the realization of the national "carbon neutrality" goal.

[0042] 5. The solar and biogas-driven SOFC multi-generation system and method described in this invention makes full use of waste heat energy to achieve multi-generation power supply, which alleviates the power supply pressure. In addition, while providing power supply, the condensate water in the condenser can be heated to provide hot water to users, meeting some of the users' heat needs.

[0043] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0044] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0045] Figure 1 This is a schematic diagram of a solar and biogas-driven SOFC combined heat and power system provided in Embodiment 1 of the present invention. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0047] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. 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 this invention pertains.

[0048] 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 scope of exemplary embodiments according to the invention. 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.

[0049] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0050] Example 1:

[0051] like Figure 1 As shown, Embodiment 1 of the present invention provides a solar and biogas-driven SOFC combined heat and power system, comprising:

[0052] Parabolic trough solar collectors, organic Rankine cycle modules, anaerobic digestion modules, SOFC modules, and Karina cycle modules;

[0053] The HotTank of the trough solar collector is connected to the first heat exchanger HE I in the organic Rankine cycle module so that the working fluid in the HotTank heats the working fluid in the organic Rankine cycle module.

[0054] The first heat exchanger HE I is connected to the second heat exchanger HE II in the anaerobic digestion module and the SOFC module, so that the low-temperature working fluid drives the anaerobic reaction tank AD. The second heat exchanger HE II is connected to the cold tank of the trough solar collector.

[0055] The exhaust gas output line of the SOFC module is connected to the regenerative steam generator HRVG of the Karina cycle module, so that the exhaust gas of the SOFC module drives the Karina cycle module to generate electricity.

[0056] In this embodiment, the working fluid used in the heat storage tank and liquid storage tank terminals of the PTSC parabolic trough solar collector is Therminol-66, a widely used heat transfer oil that can be used for heat storage in solar thermal systems.

[0057] In this embodiment, the working fluid in the organic Rankine cycle module is n-octane.

[0058] In this embodiment, the anaerobic digestion module and the SOFC module:

[0059] The anaerobic digester is connected to the second heat exchanger HE II, the anaerobic digester AD is connected to the degassing device GR, the degassing device GR is connected to the CH4 storage tank, the CH4 storage tank is connected to the fuel compressor FC, the fuel compressor FC is connected to the fuel preheater PH I, and the fuel preheater PH I is connected to the second mixer Mix II.

[0060] The water pump WP is connected to the water preheater PH II, and the water preheater PH II is connected to the air preheater PH III and the second mixer Mix II.

[0061] The air compressor AC is connected to the air preheater PH III, which is also connected to the SOFC cathode, the water preheater, and the regenerative steam generator HRVG of the Karina cycle module.

[0062] The second mixer, Mix II, is connected to the SOFC anode. The SOFC anode and SOFC cathode are connected to the combustion chamber AB, which is connected to the fuel preheater, PH I.

[0063] In this embodiment, the organic Rankine cycle module includes:

[0064] The first heat exchanger HE I is connected to the first turbine Tur I. The working fluid output from the first turbine Tur I is returned to the first heat exchanger HE I after being reheated and condensed and throttled by a pump.

[0065] In this embodiment, in the Karina loop module:

[0066] The regenerative steam generator HRVG is connected to the separator Sep. The first output of the separator Sep is connected to the second turbine Tur II. The second turbine Tur II is connected to the first mixer Mix I. The first output is ammonia-rich steam. The second output of the separator Sep is connected to the first mixer Mix I through the throttle valve Val. The second output is a weak ammonia solution.

[0067] The mixed ammonia water output from the first mixer Mix I is returned to the regenerated steam generator HRVG after condensation and pressurization.

[0068] The parameter settings for each component module are shown in Table 1.

[0069] Table 1: Input Parameters

[0070]

[0071]

[0072]

[0073] This system establishes a thermodynamic model using EES software, inputs parameter values, and calls the relevant working fluid property parameters built into EES for calculation. The calculated thermodynamic properties are shown in Table 2.

[0074] Table 2: Mechanical Properties

[0075]

[0076] Example 2:

[0077] Embodiment 2 of the present invention provides a method for SOFC combined heat and power generation driven by solar energy and biogas, comprising the following processes:

[0078] The working fluid in the storage tank of the parabolic trough solar collector heats the working fluid in the organic Rankine cycle module after flowing through the first heat exchanger.

[0079] The low-temperature working fluid flowing out of the first heat exchanger enters the second heat exchanger to drive the anaerobic reaction tank.

[0080] The exhaust gas from the SOFC module is fed into the regenerative steam generator of the Karina cycle module, which drives the Karina cycle module to generate electricity.

[0081] Specifically, including:

[0082] The heat collection process of a parabolic trough solar collector (PTSC) uses Therminol-66 as the working fluid. Therminol-66 is a widely used heat transfer oil that can be used for heat storage in solar thermal systems. First, Therminol-66 is heated by solar energy in the parabolic trough collector. Then, the working fluid is used to heat the working fluid in the organic Rankine cycle through a heat storage tank. The waste heat from the heating process, at a low temperature, drives the anaerobic reactor and then enters the storage tank.

[0083] Organic Rankine Cycle (ORC): The working fluid (n-octane) in the ORC is heated to high temperature and high pressure steam in a heat exchanger (HEI). The steam then enters a turbine (TurI) to generate electricity. After reheating and condensation throttling, the n-octane is pressurized to high pressure by a pump (PI) and then returned to the heat exchanger (HEI) to complete the cycle.

[0084] The process of anaerobic digester driving SOFC: Municipal solid waste is first biodegraded in the form of sludge in an anaerobic digester (AD) by facultative and anaerobic bacteria to produce biogas. The biogas is then degassed by a degassing device (GR) to remove impurities such as CO2 and H2S, and methane is separated out as fuel to supply the SOFC system.

[0085] In an SOFC system, air is compressed by an air compressor (AC) and preheated in an air preheater (PHⅢ) by exhaust gas from a water preheater (PHⅡ). Fuel (CH4) is pressurized by a fuel compressor (FC) and preheated in a fuel preheater (PHΙ).

[0086] In addition, the water is pressurized and preheated by a water pump (WP). Then, the superheated steam and fuel are mixed in a mixer (MixII), and the resulting mixture eventually enters the SOFC anode, while air is fed into the SOFC cathode.

[0087] Air and the mixture undergo an electrochemical reaction in the SOFC fuel cell to generate electricity. The outlet gas from the SOFC anode and cathode enters the combustion chamber (AB) and is completely combusted. The combustion gas from the combustion chamber preheats the SOFC inlet gas through a preheater. Then the exhaust gas enters the regenerative steam generator (HRVG) to drive the Karina cycle to generate electricity. Finally, the exhaust gas is released into the environment.

[0088] Karina Cycle Process: The working fluid (ammonia water) in KC is heated into a steam-water mixture in the regenerative steam generator (HRVG), and then separated into ammonia-rich vapor and a weak ammonia solution by the separator (Sep). The ammonia-rich vapor enters the turbine (Tur II) to generate electricity, and then mixes with the throttled weak ammonia solution in the mixer. The mixed ammonia water is condensed and pressurized and returned to the regenerative steam generator (HRVG) to complete the cycle.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A solar and biogas-driven SOFC (Solar-Powered Combined Heat and Power) system, characterized in that: include: Parabolic trough solar collectors, organic Rankine cycle modules, anaerobic digestion modules, SOFC modules, and Karina cycle modules; The heat storage tank of the parabolic trough solar collector is connected to the first heat exchanger in the organic Rankine cycle module so that the working fluid in the heat storage tank heats the working fluid in the organic Rankine cycle module. The first heat exchanger is connected to the second heat exchanger in the anaerobic digestion module so that the low-temperature working fluid drives the anaerobic reaction tank. The second heat exchanger is connected to the storage tank of the trough solar collector. The CH4 storage tank of the anaerobic digestion module is connected to the fuel compressor of the SOFC module, and the exhaust gas output pipeline of the SOFC module is connected to the regenerative steam generator of the Karina cycle module, so that the exhaust gas of the SOFC module drives the Karina cycle module to generate electricity.

2. The solar and biogas-driven SOFC combined heat and power system as described in claim 1, characterized in that: The working fluid used in the heat storage tank and liquid storage tank terminals of the trough solar collector is Therminol-66.

3. The solar and biogas-driven SOFC combined heat and power system as described in claim 1, characterized in that: The working fluid in the organic Rankine cycle module is n-octane.

4. The solar and biogas-driven SOFC combined heat and power system as described in claim 1, characterized in that: In the anaerobic digestion module and SOFC module: The anaerobic digester is connected to the second heat exchanger, the anaerobic digester is connected to the degassing device, the degassing device is connected to the CH4 storage tank, the CH4 storage tank is connected to the fuel compressor, the fuel compressor is connected to the fuel preheater, and the fuel preheater is connected to the second mixer. The water pump is connected to the water preheater, which is in turn connected to the air preheater and the second mixer. The air compressor is connected to the air preheater, which is also connected to the SOFC cathode, the water preheater, and the regenerative steam generator of the Karina cycle module. The second mixer is connected to the SOFC anode, and the SOFC anode and SOFC cathode are respectively connected to the combustion chamber, which is connected to the fuel preheater.

5. The solar and biogas-driven SOFC combined heat and power system as described in claim 1, characterized in that: In the organic Rankine cycle module: The first heat exchanger is connected to the first turbine. The working fluid output from the first turbine is reheated and condensed, then pressurized by a pump and returned to the first heat exchanger.

6. The solar and biogas-driven SOFC combined heat and power system as described in claim 1, characterized in that: In the Karina loop module: The regenerative steam generator is connected to the separator. The first output of the separator is connected to the second turbine, and the second turbine is connected to the first mixer. The first output is ammonia-rich steam. The second output of the separator is connected to the first mixer through a throttle valve. The second output is a weak ammonia solution. The mixed ammonia water output from the first mixer is returned to the regenerating steam generator after condensation and pressurization.

7. A method for SOFC combined heat and power generation driven by solar energy and biogas, characterized in that: Includes the following processes: The working fluid in the storage tank of the parabolic trough solar collector heats the working fluid in the organic Rankine cycle module after flowing through the first heat exchanger. The low-temperature working fluid flowing out of the first heat exchanger enters the second heat exchanger to drive the anaerobic reaction tank. The exhaust gas from the SOFC module is fed into the regenerative steam generator of the Karina cycle module, which drives the Karina cycle module to generate electricity.

8. The method for SOFC combined heat and power generation driven by solar energy and biogas as described in claim 7, characterized in that: Biogas is produced in the anaerobic digester. The biogas is then degassed to remove impurities and separate out methane for use as fuel. Air is compressed by an air compressor and preheated by exhaust gas in a water preheater in an air preheater. Methane is pressurized by a fuel compressor and preheated in a fuel preheater. Water is pressurized by a water pump and preheated in a water preheater. Preheated steam and preheated fuel are mixed in a second mixer, and the resulting mixture eventually enters the SOFC anode, while preheated air is sent to the SOFC cathode. Air and the mixture undergo an electrochemical reaction in the SOFC to generate electricity. The outlet gas from the SOFC anode and SOFC cathode enters the combustion chamber and is completely combusted. The combustion gas from the combustion chamber enters the fuel preheater to preheat the methane. The exhaust gas from the air preheater enters the regenerative steam generator to drive the Karina cycle to generate electricity, and finally the exhaust gas is released into the environment.

9. The method for SOFC combined heat and power generation driven by solar energy and biogas as described in claim 7, characterized in that: In the Karina cycle module, the working fluid is heated into a steam-water mixture in the regenerative steam generator. After passing through a separator, it is separated into ammonia-rich vapor and a weak ammonia solution. The ammonia-rich vapor enters the second turbine to generate electricity. Then, it is mixed with the throttled weak ammonia solution in the first mixer. The mixed ammonia water is condensed and pressurized before returning to the regenerative steam generator to complete the cycle.

10. The method for SOFC combined heat and power generation driven by solar energy and biogas as described in claim 7, characterized in that: In the organic Rankine cycle, the working fluid is heated to high-temperature, high-pressure steam in the first heat exchanger. The steam then enters the first turbine to generate electricity. After reheating and condensation throttling, the working fluid is pressurized to high pressure by a pump and then returns to the first heat exchanger to complete the cycle.

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