Anaerobic fermentation heat preservation system combining direct combustion and biogas slurry waste heat utilization

Abstract

The utility model belongs to the technical field of anaerobic fermentation, and provides a direct combustion and biogas slurry waste heat utilization combined anaerobic fermentation heat preservation system which comprises a biomass direct combustion boiler, a heat exchanger, a sewage source heat pump and a heat exchange coil pipe arranged in a fermentation tank, and a biogas residue and biogas slurry mixture outlet of the fermentation tank is connected with the sewage source heat pump; a water inlet and a water outlet of the biomass direct-fired boiler are connected with the primary side of the heat exchanger to form a first circulation loop of a first circulation medium; a water inlet and a water outlet of the heat exchange coil pipe are connected with the secondary side of the heat exchanger to form a circulation loop of a second circulation medium; and a water inlet and a water outlet of the sewage source heat pump are connected with the primary side of the heat exchanger to form a second circulation loop of the first circulation medium. The biogas yield of an anaerobic fermentation project can be obviously increased, and the energy utilization efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of anaerobic fermentation, and in particular relates to an anaerobic fermentation insulation system combining direct combustion with biogas slurry waste heat utilization. Background Art

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

[0003] Currently, large-scale anaerobic fermentation systems primarily utilize mesophilic fermentation. The primary method for maintaining fermentation temperature is through the use of biogas boilers, utilizing heat generated by coal-fired biogas production. While this method eliminates the need for an external heat source, it consumes system-generated biogas, reducing usable biogas production. In particularly cold and frigid climates, the amount of biogas required to maintain fermentation temperature can exceed 20% of the total, significantly impacting usable biogas production. Furthermore, the fermentation liquid temperature remains above 30°C, leaving this waste heat largely unused, resulting in low system efficiency. Utility Model Content

[0004] In order to solve the above problems, the utility model proposes an anaerobic fermentation insulation system that combines direct combustion with waste heat utilization of biogas slurry. The system uses biomass direct combustion and waste heat utilization of biogas slurry to provide heat for the insulation of the fermentation tank, replacing the heat provided by biogas combustion. This can significantly increase the biogas production of the anaerobic fermentation project and improve energy utilization efficiency.

[0005] According to some embodiments, the present invention adopts the following technical solutions:

[0006] In the first aspect, an anaerobic fermentation and heat preservation system combining direct combustion with waste heat utilization of biogas slurry is proposed, comprising a biomass direct-fired boiler, a heat exchanger, a sewage-source heat pump, and a heat exchange coil disposed in a fermentation tank, wherein the outlet of the biogas residue and biogas slurry mixture in the fermentation tank is connected to the sewage-source heat pump;

[0007] The water inlet and the water outlet of the biomass direct-fired boiler are both connected to the primary side of the heat exchanger to form a first circulation loop of the first circulating medium;

[0008] The water inlet and outlet of the heat exchange coil are both connected to the secondary side of the heat exchanger to form a circulation loop for the second circulating medium;

[0009] The water inlet and the water outlet of the sewage source heat pump are both connected to the primary side of the heat exchanger to form a second circulation loop of the first circulating medium.

[0010] Furthermore, the feed inlets of the fermentation tank and the biomass direct-fired boiler are both connected to a biomass storage device.

[0011] Furthermore, a feeder is provided on the connecting pipe between the feed inlet of the biomass direct-fired boiler and the biomass storage device.

[0012] Furthermore, a solid-liquid separation device and a biogas liquid pool are provided on the connecting pipe between the outlet of the mixture of biogas residue and biogas liquid of the fermentation tank and the sewage source heat pump.

[0013] Furthermore, a third valve and a sewage source heat pump are provided on the connecting pipe between the biogas slurry pool and the sewage source heat pump.

[0014] Furthermore, a first circulating water pump and a first valve are provided on the connecting pipe between the water inlet of the biomass direct-fired boiler and the primary side of the heat exchanger.

[0015] Furthermore, a first temperature sensor and a first flow sensor are provided on the connecting pipe between the water outlet of the biomass direct-fired boiler and the primary side of the heat exchanger.

[0016] Furthermore, a third circulation pump and a fourth valve are provided on the connecting pipe between the water inlet of the sewage source heat pump and the primary side of the heat exchanger.

[0017] Furthermore, a fourth temperature sensor and a second flow sensor are provided on the connecting pipe between the water outlet of the sewage source heat pump and the primary side of the heat exchanger.

[0018] Furthermore, a third temperature sensor is provided in the fermentation tank.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] The utility model provides an anaerobic fermentation insulation system that combines direct combustion with waste heat utilization of biogas slurry. It uses biomass direct combustion and waste heat utilization of biogas slurry to provide heat for fermentation tank insulation, replacing biogas combustion to provide heat, which can significantly increase the biogas production of anaerobic fermentation projects and reduce unit investment.

[0021] The utility model provides an anaerobic fermentation insulation system combining direct combustion with biogas slurry waste heat utilization, which can significantly improve the energy utilization efficiency of the system and reduce unit energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0023] Figure 1 It is a schematic diagram of the overall structure of an anaerobic fermentation and heat preservation system that combines direct combustion with biogas slurry waste heat utilization in the present utility model. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0026] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the term "comprising" is used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0027] In the present invention, terms such as "upper", "vertical", "horizontal", "upward", "downward", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention. They do not specifically refer to any part or element in the present invention and cannot be understood as limitations on the present invention.

[0028] In this utility model, terms such as "fixed" and "fixed" should be interpreted broadly to mean a fixed connection, an integral connection, or a detachable connection. Relevant researchers or technicians in this field may determine the specific meaning of these terms in this utility model based on specific circumstances, and they should not be construed as limiting this utility model.

[0029] This embodiment provides an anaerobic fermentation and heat preservation system that combines direct combustion with biogas slurry waste heat utilization.

[0030] This embodiment provides an anaerobic fermentation and heat preservation system that combines direct combustion with waste heat utilization of biogas slurry. Figure 1 As shown, it includes: a fermentation tank 1, a biomass direct-fired boiler 4, a solid-liquid separation device 7, a biogas slurry tank 8, a sewage source heat pump 9, a heat exchanger 5, and a heat exchange coil 6. The heat exchanger 5 and the heat exchange coil 6 constitute the reactor insulation system.

[0031] The heat exchange coil 6 is arranged around the inner wall of the fermentation tank 1 .

[0032] The feed inlets of the fermentation tank 1 and the biomass direct-fired boiler 4 are both connected to a biomass storage device in the biomass (straw) storage area, for example, a storage silo for storing biomass fuel.

[0033] The water inlet and outlet of the biomass direct-fired boiler 4 are both connected to the primary side of the heat exchanger 5, forming a first circulation loop for the first circulating medium. The water inlet and outlet of the heat exchange coil 6 are both connected to the secondary side of the heat exchanger 5, forming a circulation loop for the second circulating medium. The water inlet and outlet of the sewage-source heat pump 9 are both connected to the primary side of the heat exchanger 5, forming a second circulation loop for the first circulating medium. The heat exchanger 5 is used to exchange heat between the first circulating medium and the second circulating medium.

[0034] The biomass straw stored in the storage area, serving as fermentation feedstock, is connected to a biomass direct-fired boiler 4 via a straw crushing device 2 and a feeder 3. The biomass direct-fired boiler 4 is connected to the primary side of a heat exchanger 5. The inlet pipe of the biomass direct-fired boiler 4 is equipped with a first circulating water pump 10 and a first valve 11, while the outlet pipe of the biomass direct-fired boiler 4 is equipped with a first temperature sensor 12 and a first flow sensor 13. The secondary side of the heat exchanger 5 is connected to a heat exchange coil 6, which is located within the fermenter 1. The inlet pipe of the heat exchange coil 6 is equipped with a second temperature sensor 14, while the outlet pipe of the heat exchange coil 6 is equipped with a second circulating water pump 15 and a second valve 16. A third temperature sensor 17 is located within the fermenter.

[0035] The outlet of the biogas residue and biogas slurry mixture from fermentation tank 1 is connected to the primary side of sewage-source heat pump 9 via solid-liquid separation device 7, biogas slurry tank 8, biogas slurry pump 18, and third valve 19. The secondary water inlet of sewage-source heat pump 9 is connected to the primary water outlet of heat exchanger 5, and the secondary water outlet of sewage-source heat pump 9 is connected to the primary water inlet of heat exchanger 5. A third circulating pump 20 and a fourth valve 21 are installed on the secondary water inlet pipe of sewage-source heat pump 9, and a fourth temperature sensor 22 and a second flow sensor 23 are installed on the secondary water outlet pipe of sewage-source heat pump 9.

[0036] This embodiment provides a method for operating an anaerobic fermentation and heat preservation system that combines direct combustion with biogas slurry waste heat utilization, comprising the following steps:

[0037] (1) The biomass straw used as the fermentation raw material stored in the storage area is crushed by the straw crushing equipment 2 and then enters the biomass direct-fired boiler 4 through the feeder 3 to heat the first circulating medium;

[0038] (2) The heated first circulating medium enters the heat exchanger 5 to release heat, and the first temperature sensor 12 and the first flow sensor 13 respectively record the temperature and flow of the first circulating medium in the pipeline;

[0039] (3) When the temperature displayed by the third temperature sensor 17 is lower than the set temperature, the first valve 11 is opened, the first circulating water pump 10 is turned on, and the first circulating medium after releasing heat flows back to the biomass direct-fired boiler 4;

[0040] (4) The second circulating medium exchanges heat with the first circulating medium in the heat exchanger 5; the heated second circulating medium enters the heat exchange coil 6, which insulates the fermenter 1, and the second temperature sensor 14 records the temperature of the heated second circulating medium in the pipe;

[0041] (5) When the first circulating water pump 10 is turned on, the second circulating water pump 15 and the second valve 16 are turned on, and the cooled second circulating medium flows back to the heat exchanger 5;

[0042] (6) The biomass straw used as fermentation raw material stored in the storage area enters the fermentation tank 1. The third temperature sensor 17 records the temperature inside the fermentation tank 1. Under the premise of heat preservation by the heat exchange coil 6, fermentation is carried out to obtain biogas. The mixture of biogas residue and biogas liquid enters the solid-liquid separation device 7, the biogas residue is filtered out, and the biogas liquid enters the biogas liquid tank 8;

[0043] (7) When the temperature displayed by the third temperature sensor 17 is lower than the set temperature, the biogas slurry pump 18 and the third valve 19 are opened, and the biogas in the biogas slurry tank 8 enters the sewage source heat pump 9. The sewage source heat pump 9 extracts the waste heat of the biogas slurry and generates heat. The temperature of the biogas slurry after the waste heat is extracted is reduced and the biogas slurry is transported out. The heat generated by the sewage source heat pump 9 heats the first circulating medium.

[0044] (8) The heated first circulating medium enters the heat exchanger 5 to release heat, and the fourth temperature sensor 22 and the second flow sensor 23 respectively record the temperature and flow of the first circulating medium in the pipeline;

[0045] (8) When the biogas slurry pump 18 is turned on, the third circulation pump 20 and the fourth valve 21 are opened, and the first circulating medium after releasing heat flows back to the sewage source heat pump 9.

[0046] Straw, one of the fermentation feedstocks, undergoes pretreatment, including screening and crushing, before being fed by a feeder to a biomass direct-fired boiler for combustion. The resulting hot water is pumped by the boiler's circulating pump to a heat exchanger, where it transfers heat to the fermenter's insulation system, providing the necessary heat for fermentation. Temperature sensors are installed inside the fermenter and on the fermenter's insulation system to monitor whether the system's heating temperature meets fermentation requirements. A temperature sensor is also installed on the boiler's outlet water line to monitor the inlet temperature of the heat exchanger's primary side to ensure performance.

[0047] After the raw materials are fermented in the fermentation tank, the slag liquid undergoes solid-liquid separation, and the generated biogas slurry is placed in a biogas pool and transported to the primary side of the sewage source heat pump through a biogas pump. The sewage heat pump uses the heat of the biogas slurry on the primary side to generate hot water, which is transported to the primary side inlet of the heat exchanger through a circulation pump. After mixing with the hot water generated by the boiler, it enters the heat exchanger to provide heat for the fermentation tank insulation system. A temperature sensor is provided on the secondary side water supply pipeline of the sewage source heat pump and is connected to the sewage source heat pump control to ensure that the water supply temperature of the sewage source heat pump is consistent with the water supply temperature of the boiler.

[0048] To improve overall efficiency, waste heat from biogas slurry should be prioritized for heat generation, with the shortfall provided by the direct-fired boiler. To this end, flow sensors are installed on both the secondary water supply piping of the sewage-source heat pump and the boiler water supply piping to monitor their respective water flow rates. A regulating valve is also installed on the boiler water supply piping to adjust and limit water flow on the boiler side, ensuring that heat provided by the sewage-source heat pump is prioritized.

[0049] This embodiment provides an anaerobic fermentation insulation system that combines direct combustion with waste heat utilization of biogas slurry. It utilizes the combustion of anaerobic fermentation raw materials and the utilization of waste heat from biogas slurry to provide heat for the insulation of the fermentation system, replacing the heat provided by biogas combustion. This can significantly increase the product output of the anaerobic fermentation system in cold and extremely cold regions, increase project product revenue, reduce the equipment scale of the fermentation system, and reduce unit investment.

[0050] This embodiment provides an anaerobic fermentation insulation system that combines direct combustion with waste heat utilization of biogas slurry. Because the direct combustion system has a high thermal efficiency and the heat pump system has a high performance coefficient, the combination of direct combustion and waste heat utilization of biogas slurry can significantly improve the energy utilization efficiency of the system and reduce unit energy consumption.

[0051] The anaerobic fermentation insulation system provided in this embodiment combines direct combustion with waste heat utilization of biogas slurry, which can increase the biogas production of anaerobic fermentation projects, improve system efficiency, reduce unit investment, improve project profitability, and contribute to the development and promotion of anaerobic fermentation projects.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An anaerobic fermentation and heat preservation system combining direct combustion with biogas slurry waste heat utilization, characterized in that: It includes a biomass direct-fired boiler, a heat exchanger, a sewage-source heat pump, and a heat exchange coil arranged in a fermentation tank, and the outlet of the mixture of biogas residue and biogas liquid in the fermentation tank is connected to the sewage-source heat pump; The water inlet and the water outlet of the biomass direct-fired boiler are both connected to the primary side of the heat exchanger to form a first circulation loop of the first circulating medium; The water inlet and outlet of the heat exchange coil are both connected to the secondary side of the heat exchanger to form a circulation loop for the second circulating medium; The water inlet and the water outlet of the sewage source heat pump are both connected to the primary side of the heat exchanger to form a second circulation loop of the first circulating medium.

2. The anaerobic fermentation and heat preservation system combining direct combustion and biogas slurry waste heat utilization according to claim 1 is characterized in that: The feed inlets of the fermentation tank and the biomass direct-fired boiler are both connected to the biomass storage device.

3. The anaerobic fermentation and heat preservation system combining direct combustion and biogas slurry waste heat utilization according to claim 2, characterized in that: A feeder is provided on the connecting pipe between the feed inlet of the biomass direct-fired boiler and the biomass storage device.

4. The anaerobic fermentation and heat preservation system combining direct combustion and biogas slurry waste heat utilization according to claim 1, characterized in that: A solid-liquid separation device and a biogas liquid pool are provided on the connecting pipeline between the outlet of the biogas residue and biogas liquid mixture of the fermentation tank and the sewage source heat pump.

5. The anaerobic fermentation and heat preservation system combining direct combustion with biogas slurry waste heat utilization according to claim 4, characterized in that: A third valve and a sewage source heat pump are provided on the connecting pipe between the biogas slurry pool and the sewage source heat pump.

6. The anaerobic fermentation and heat preservation system combining direct combustion and biogas slurry waste heat utilization according to claim 1, characterized in that: A first circulating water pump and a first valve are provided on the connecting pipe between the water inlet of the biomass direct-fired boiler and the primary side of the heat exchanger.

7. The anaerobic fermentation and heat preservation system combining direct combustion with biogas slurry waste heat utilization according to claim 1, characterized in that: A first temperature sensor and a first flow sensor are provided on a connecting pipe between the water outlet of the biomass direct-fired boiler and the primary side of the heat exchanger.

8. The anaerobic fermentation and heat preservation system combining direct combustion with biogas slurry waste heat utilization according to claim 1, characterized in that: A third circulation pump and a fourth valve are provided on the connecting pipe between the water inlet of the sewage source heat pump and the primary side of the heat exchanger.

9. The anaerobic fermentation and heat preservation system combining direct combustion with biogas slurry waste heat utilization according to claim 1, characterized in that: A fourth temperature sensor and a second flow sensor are provided on the connecting pipe between the water outlet of the sewage source heat pump and the primary side of the heat exchanger.

10. The anaerobic fermentation and heat preservation system combining direct combustion with biogas slurry waste heat utilization according to claim 1, characterized in that: A third temperature sensor is provided in the fermentation tank.

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