Hot water- hot plate evaporation concentration system

Abstract

The utility model relates to the technical field of evaporation concentration, especially a hot water-hot plate evaporation concentration system. The system comprises: a hot plate evaporation module, including a hot plate evaporator and a separator in communication with the hot plate evaporator; the hot plate evaporator is provided with a biogas slurry inlet, a hot water inlet, a hot water outlet and a concentrated liquid outlet; the biogas slurry inlet is connected to the biogas slurry to be evaporated and concentrated; the hot water inlet is connected to hot water at a first temperature; the hot water outlet discharges hot water at a second temperature; the concentrated liquid outlet discharges the liquid after the biogas slurry is concentrated; a condensing module, including a condenser connected to the separator; the condenser is arranged to collect the steam discharged from the separator, condense the steam into liquid water, spray the liquid water into the separator for cooling and recover the liquid water. The utility model reduces heat energy loss through plate-type indirect heat exchange, and the linkage design of the separator and the condenser recovers the latent heat of the steam.

Description

Technical Field

[0001] This utility model relates to the field of evaporation and concentration technology, and in particular to a hot water-hot plate evaporation and concentration system. Background Technology

[0002] In daily farming operations, livestock farms generate a large amount of manure. If left untreated, this manure not only occupies a significant amount of land but also emits foul odors, causing serious pollution to the surrounding environment. To achieve resource recycling and environmental protection, farms typically ferment this manure to produce biogas and biogas slurry. Biogas can be used for power generation or heating, while biogas slurry, rich in nutrients such as nitrogen, phosphorus, and potassium, has high fertilizing value and is a high-quality organic fertilizer.

[0003] However, a significant problem with current biogas slurry is its excessively high water content. High water content increases transportation costs because the transported component is primarily water, not the effective fertilizer components. Furthermore, high water content makes storage more difficult, requiring larger storage spaces to contain the excess water. In addition, due to insufficient concentration, larger quantities of biogas slurry are needed to achieve the desired fertilization effect, which not only increases fertilization costs but may also burden the soil and reduce fertilization efficiency due to excessive application.

[0004] Therefore, to effectively address these issues, livestock farms urgently need to adopt evaporation and concentration processes to reduce the water content of biogas slurry. Evaporation and concentration remove some of the water from the biogas slurry, thereby increasing its concentration. This not only reduces transportation and storage costs but also improves fertilization efficiency, making the application of biogas slurry in farmland more efficient. Furthermore, concentrated biogas slurry becomes more competitive in the market, bringing better economic benefits whether used on farmland or sold externally. Through this volume reduction process, livestock farms can better achieve resource recycling, improve the economic efficiency and practicality of resource utilization, and contribute to the sustainable development of agriculture. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model discloses a hot water-hot plate evaporation and concentration system.

[0006] The technical solution adopted in this utility model is as follows: A hot water-hot plate evaporation and concentration system, comprising: A hot plate evaporation module includes a hot plate evaporator and a separator connected to the hot plate evaporator; the hot plate evaporator is provided with a biogas slurry inlet, a hot water inlet, a hot water outlet, and a concentrate outlet; the biogas slurry inlet is fed with biogas slurry to be evaporated and concentrated; the hot water inlet is fed with hot water at a first temperature; the hot water outlet discharges hot water at a second temperature; and the concentrate outlet discharges concentrated biogas slurry liquid. A condensation module includes a condenser connected to the separator; the condenser is configured to collect the steam discharged from the separator, condense it into liquid water, spray it into the separator for cooling, and recover the liquid water.

[0007] In one embodiment of this utility model, the condensation module further includes an ejector connected to the condenser and a secondary steam condensate tank connected to the ejector; the secondary steam condensate tank is equipped with a heat exchanger, the heat exchanger is supplied with circulating water, and the steam collected by the condenser is cooled and condensed into condensate by the circulating water.

[0008] In one embodiment of the present invention, the condensation module further includes a secondary steam condensate pump connected to the outlet of the secondary steam condensate tank.

[0009] In one embodiment of this invention, the condenser is supplied with circulating cooling water.

[0010] In one embodiment of this utility model, the separator is connected to a defoaming module; the defoaming module is configured to reduce the formation of bubbles and foam in the liquid within the separator.

[0011] In one embodiment of the present invention, the defoaming module includes a foam sensor disposed on the separator and a defoaming agent tank connected to the hot plate evaporator; the defoaming agent tank stores defoaming agent.

[0012] In one embodiment of this utility model, the defoamer is one of an acidic solution, an alkaline solution, and hot water.

[0013] In one embodiment of the present invention, the hot plate evaporation module further includes a concentrate discharge pump connected to the concentrate outlet of the hot plate evaporator.

[0014] In one embodiment of this utility model, the first temperature is 90°C; the second temperature is 80°C.

[0015] In one embodiment of the present invention, a biogas slurry storage tank is further included, which is connected to the biogas slurry inlet of the hot plate evaporator; the biogas slurry storage tank is configured to store biogas slurry to be evaporated and concentrated.

[0016] The above-mentioned technical solution of this utility model has the following advantages compared with the prior art: Compared to existing technologies, conventional evaporation systems mostly use direct steam heating, failing to achieve cascade utilization of hot water. The hot water-plate evaporator described in this invention reduces heat loss through plate-type indirect heat exchange, and the linked design of the separator and condenser allows for the recovery of latent heat of steam. Traditional processes directly discharge condensate, resulting in resource waste; this system uses a spray structure to reuse condensate for system cooling, forming a dual cycle of heat energy and water resources.

[0017] The hot water-hot plate evaporator described in this invention can be applied to the fermentation industry. Specifically, biogas is produced by the fermentation of biogas slurry, and the biogas is used to generate electricity. During the power generation process, 90°C hot water is generated. The hot plate evaporator uses the 90°C hot water to indirectly transfer heat to the biogas slurry through a hot plate heat exchanger. The hot water temperature drops from 90°C to 80°C, while the biogas slurry temperature increases from 25°C to 60°C. The biogas slurry is then depressurized and cooled in a separator to lower the boiling point of the biogas slurry, thereby achieving vapor-liquid separation and the purpose of evaporation and concentration. Attached Figure Description

[0018] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] Figure 1 This is a schematic diagram of the hot water-hot plate evaporation and concentration system in this utility model.

[0020] Figure 2 yes Figure 1 A partially enlarged schematic diagram of the medium-heat plate evaporation module.

[0021] Figure 3 yes Figure 1 A partially enlarged schematic diagram of the intermediate condenser module.

[0022] Figure 4 yes Figure 1 A partially enlarged schematic diagram of the secondary condensation mechanism.

[0023] Explanation of the reference numerals in the accompanying drawings: 10, hot plate evaporator; 20, separator; 30, concentrate discharge pump; 40, biogas slurry storage tank; 50, condenser; 60, ejector; 70, secondary steam condensate tank; 80, secondary steam condensate pump; 90, defoamer tank. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.

[0025] The foregoing and other technical contents, features, and effects of this utility model will be clearly presented in the following detailed description of the embodiments with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front, or back, are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the present utility model. Furthermore, in all embodiments, the same reference numerals denote the same elements.

[0026] In existing technologies, the biogas slurry produced from the fermentation of livestock and poultry manure suffers from high moisture content, leading to increased transportation costs, storage difficulties, and low fertilization efficiency. Traditional evaporation and concentration processes suffer from insufficient heat energy utilization and inadequate secondary steam recovery, resulting in water waste during treatment and hindering efficient concentration. When a large-scale farm used conventional evaporation equipment to treat biogas slurry, direct steam emission caused heat loss, and fluctuations in the concentration of the concentrate affected subsequent resource utilization.

[0027] To address these issues, technicians discovered that conventional evaporation systems were not effectively utilizing waste heat resources, and the separation of steam resulted in high energy consumption due to the lack of recycling. Analysis of the heat exchange process revealed that linking the evaporator and condenser could create a closed-loop thermal energy system. Further consideration was given to the recovery and reuse of steam condensate, proposing the installation of a spray cooling structure at the top of the separator to reduce the system temperature gradient and achieve water recycling.

[0028] Therefore, combining Figures 1 to 4 This embodiment describes a system comprising a hot plate evaporation module and a condensation module. The hot plate evaporation module has a hot plate evaporator 10 and a separator 20 connected to the hot plate evaporator 10. The hot plate evaporator 10 is provided with a biogas slurry inlet, a hot water inlet, a hot water outlet, and a concentrate outlet. The condensation module includes a condenser 50 connected to the separator 20, which collects steam, condenses it, sprays it back to the separator 20 for cooling, and recovers liquid water.

[0029] The hot plate evaporator 10 is a device that achieves indirect contact between biogas slurry and hot water through a plate heat exchange structure. Specifically, it can be implemented using corrugated plates or honeycomb plates, increasing the heat exchange area to improve evaporation efficiency. The separator 20 is a container for gas-liquid separation, which can be achieved using centrifugal separation to effectively separate the steam generated by evaporation from the concentrated liquid. The condenser 50 is a device that converts steam into liquid water, which can be implemented using a shell-and-tube or plate heat exchanger, using circulating cooling water to remove the latent heat of the steam. Spray cooling refers to atomizing the condensate and spraying it into the interior of the separator 20, which can be achieved using pressure nozzles or rotating nozzles, reducing the temperature through contact between the droplets and the steam.

[0030] This embodiment further proposes that the condensation module also includes an ejector 60 connected to the condenser 50 and a secondary steam condensate tank 70 connected to the ejector 60; the secondary steam condensate tank 70 is equipped with a heat exchanger, and circulating water is introduced into the heat exchanger. The steam collected by the condenser 50 is cooled and condensed into condensate by the circulating water.

[0031] Among them, the ejector 60 refers to a mixing device that uses high-speed fluid to induce low-pressure steam, specifically implemented using a Venturi tube structure, creating a negative pressure zone through the flow of circulating water to draw in steam. The secondary steam condensate tank 70 is a sealed container used to collect incompletely condensed secondary steam, specifically implemented using a welded stainless steel structure. The heat exchanger is a device used for heat exchange, specifically implemented using a shell-and-tube structure, achieving heat transfer through indirect contact between circulating water and steam.

[0032] Specifically, after the steam generated by the hot plate evaporator 10 enters the separator 20, the secondary steam that is not completely condensed is drawn into the secondary steam condensate tank 70 through the ejector 60. The circulating water exchanges heat with the steam in the tank through a heat exchanger, further cooling the steam to below the dew point to form condensate.

[0033] This embodiment further proposes that the condensation module also includes a secondary steam condensate pump 80 connected to the outlet of the secondary steam condensate tank 70.

[0034] The secondary steam condensate pump 80 refers to a liquid conveying device installed at the outlet of the secondary steam condensate tank 70. It can be implemented using a centrifugal pump or a plunger pump, and is used to pressurize and discharge the condensate formed after the secondary cooling of the circulating water in the tank. This pump maintains the pressure balance inside the tank through active conveying, preventing condensate accumulation and a decrease in heat exchange efficiency.

[0035] Specifically, after the heat exchange between steam and circulating water is completed inside the secondary steam condensate tank 70, the condensate is collected through the outlet pipe. The secondary steam condensate pump 80 is configured to start at the outlet at the bottom of the tank, delivering liquid water at a constant flow rate to the external recovery system or circulation pipeline. The pump's operation can be controlled in conjunction with a liquid level sensor, automatically starting and stopping when the liquid level in the tank reaches a preset threshold, thereby preventing abnormal pressure fluctuations inside the tank caused by condensate retention.

[0036] This embodiment further proposes that condenser 50 be supplied with circulating cooling water. Circulating cooling water refers to a cooling medium that circulates through a closed pipeline, specifically an industrial circulating water system, which can continuously remove the heat released during steam condensation.

[0037] Specifically, in the hot plate evaporation and concentration system, the condenser 50 cools the steam discharged from the separator 20 by introducing circulating cooling water. After entering the condenser 50, the steam exchanges heat with the circulating cooling water, releasing latent heat and condensing into liquid water. The circulating cooling water absorbs heat, its temperature rises, and it is then cooled by external cooling equipment before returning to the condenser 50, forming a closed loop. This process not only enables continuous and efficient steam condensation but also avoids the waste of disposable cooling water.

[0038] It should be noted that after the biogas slurry is heated to 60℃, it enters the separator 20. A vacuum pump can be used to evacuate the vacuum (pressure reduced to 0.05MPa-0.08MPa), and a small amount of low-temperature condensate can be sprayed (temperature reduced to 55-60℃). Under the dual action, the boiling point of the biogas slurry drops from 100℃ (at normal pressure) to 55℃-65℃. At this time, the temperature of the biogas slurry is 60℃, which is slightly higher than its own boiling point. It will quickly vaporize to generate secondary steam. Finally, the vapor-liquid separation is completed in the separator 20, with steam (water) on top and concentrated liquid at the bottom.

[0039] This embodiment further proposes a defoaming module connected to the separator 20; the defoaming module is configured to reduce the formation of bubbles and foam in the liquid within the separator 20. The defoaming module is a device used to suppress or eliminate the aggregation of bubbles in the liquid, its function being to disrupt the surface tension of the liquid to break down the foam structure.

[0040] Specifically, during the operation of the hot plate evaporation and concentration system, when the biogas slurry is heated and generates steam within the separator 20, it easily forms bubbles and a foam layer. The defoaming module monitors the liquid level within the separator 20 in real time, for example, using a liquid level sensor or optical detection device, and triggers the defoamer spraying mechanism to spray defoamer onto the liquid surface. Upon contact with the foam, the defoamer rapidly reduces surface tension, causing the bubbles to burst and accelerating gas-liquid separation, thereby preventing foam accumulation and blockage of the steam passage. Simultaneously, the defoaming module can be configured with a circulation pipeline to reintroduce the separated liquid into the evaporation process, ensuring continuous system operation.

[0041] This embodiment further proposes a defoaming module including a foam sensor located in the separator 20 and a defoaming agent tank 90 connected to the hot plate evaporator 10, wherein the defoaming agent tank 90 stores defoaming agent.

[0042] Among them, the foam sensor refers to the detection device used to monitor the foam height on the liquid surface inside the separator 20 in real time. Specifically, it can be implemented by capacitive or optical sensors, and the defoamer spraying action is triggered by electrical signal feedback.

[0043] Among them, the defoamer tank 90 refers to a container used to store and quantitatively deliver defoamer. Specifically, it can be a pressure tank with a metering pump, which is connected to the hot plate evaporator 10 through a pipeline to control the amount of defoamer added.

[0044] Specifically, when excessive foam is generated during the evaporation of biogas slurry in separator 20, the foam sensor detects that the foam height on the liquid surface exceeds a preset threshold and transmits a signal to the control system. Subsequently, the defoamer in defoamer tank 90 is injected into the hot plate evaporator 10 through a pipeline or directly sprayed into separator 20. After the defoamer comes into contact with the foam, it breaks its surface tension, causing the foam to burst, thereby reducing the accumulation of bubbles and foam in separator 20 and avoiding a decrease in evaporation efficiency or equipment blockage due to foam overflow.

[0045] This embodiment further proposes that the defoamer is one of acidic solution, alkaline solution and hot water.

[0046] Acidic solutions refer to liquids with a pH value below 7, which can be achieved using dilute sulfuric acid or dilute hydrochloric acid solutions. These neutralize the alkaline substances in the biogas slurry, disrupting the surface tension of the bubbles. Alkaline solutions refer to liquids with a pH value above 7, which can be achieved using sodium hydroxide or sodium carbonate solutions. These adjust the pH of the biogas slurry to reduce foam stability. Hot water refers to liquid water with a temperature higher than ambient temperature. This can be achieved by using waste heat generated by the hot plate evaporation module to heat the circulating water, accelerating bubble collapse through temperature changes.

[0047] This embodiment further proposes that the hot plate evaporation module also includes a concentrate discharge pump 30 connected to the concentrate outlet of the hot plate evaporator 10.

[0048] The concentrate discharge pump 30 refers to the power unit used to transport the concentrated liquid. Specifically, it can be a corrosion-resistant screw pump or centrifugal pump with self-priming capability. It uses mechanical action to stably discharge the concentrated liquid from inside the evaporator. This pump plays a role in maintaining the continuous flow of the concentrated liquid in the system, preventing pipeline blockage caused by excessively high liquid viscosity or poor flowability.

[0049] Specifically, the concentrate discharge pump 30 is directly connected to the concentrate outlet of the hot plate evaporator 10 via a pipeline. After the hot plate evaporator 10 completes the evaporation and concentration of the biogas slurry, the concentrate enters the inlet of the concentrate discharge pump 30 under gravity or pressure. The pump body pressurizes the liquid and delivers it to an external storage or subsequent processing unit through the rotation of the impeller or screw. During this process, the pump body's sealing structure prevents concentrate leakage, while the selection of corrosion-resistant materials is adapted to the high salinity characteristics of the biogas slurry.

[0050] This embodiment further proposes that the hot plate evaporator 10 is provided with a biogas slurry inlet, a hot water inlet, a hot water outlet and a concentrate outlet. The biogas slurry to be evaporated and concentrated is introduced into the biogas slurry inlet, hot water at a first temperature is introduced into the hot water inlet, hot water at a second temperature is discharged from the hot water outlet, and the concentrated liquid after biogas slurry is discharged from the concentrate outlet. The first temperature is 90°C and the second temperature is 80°C.

[0051] The first temperature refers to the initial temperature of the hot water entering the hot plate evaporator 10. This can be achieved by using an external heat source to heat the hot water to a set temperature before introducing it into the system. This temperature range provides sufficient heat for the evaporation of biogas slurry. The second temperature refers to the temperature of the hot water discharged from the hot plate evaporator 10. This can be achieved by controlling the heat exchange efficiency of the hot plate evaporator 10 or adjusting the hot water flow rate. This temperature difference reflects the effective transfer of heat energy during the evaporation process.

[0052] Specifically, during the evaporation and concentration process, 90°C hot water enters the hot plate evaporator 10 through the hot water inlet. After heat exchange with the biogas slurry, its temperature drops to 80°C, and it is then discharged from the hot water outlet. During this process, some of the water in the biogas slurry evaporates to form steam after absorbing heat, and the remaining concentrated liquid is discharged through the concentrated liquid outlet. By setting the difference between the first and second temperatures, the thermal energy utilization rate of the hot plate evaporator 10 can be controlled, ensuring a balance between evaporation efficiency and energy consumption. It should be noted that the metal plate wall of the hot plate evaporator 10 (such as 316L stainless steel) enables indirect heat exchange between the 90°C hot water and the biogas slurry—the hot water side releases heat (90°C → 80°C), and the biogas slurry side absorbs heat (25°C → 60°C). The two do not come into direct contact, preventing ammonia nitrogen and humic acid in the biogas slurry from corroding the hot water pipes and also preventing hot water from contaminating the biogas slurry. One ton of 90℃ hot water can release about 42MJ of heat when cooled by 10℃ (calculated based on the specific heat capacity of water of 4.2kJ / (kg·℃)). This heat can heat about 1.2 tons of biogas slurry from 25℃ to 60℃, with a heat utilization rate of over 75%.

[0053] This embodiment further proposes a biogas slurry storage tank 40 connected to the biogas slurry inlet of the hot plate evaporator 10; the biogas slurry storage tank 40 is configured to store biogas slurry to be evaporated and concentrated.

[0054] The biogas slurry storage tank 40 refers to a container used for temporary storage of biogas slurry to be treated. It can be made of corrosion-resistant materials and equipped with a liquid level monitoring device to ensure a stable feed source for the evaporation and concentration system during processing. Connection refers to forming a fluid passage between the biogas slurry storage tank 40 and the biogas slurry inlet of the hot plate evaporator 10 via a pipeline.

[0055] Specifically, the biogas slurry storage tank 40 is sealed to the biogas slurry inlet of the hot plate evaporator 10 via a pipeline. The stored biogas slurry to be treated enters the hot plate evaporator 10 for evaporation and concentration via gravity flow or pumping. During system operation, the capacity design of the biogas slurry storage tank 40 ensures the continuity of the treatment process and avoids fluctuations in evaporation efficiency due to interruption of feed. The biogas slurry level in the storage tank is monitored in real time by a liquid level monitoring device. When the liquid level is lower than a set threshold, an alarm or automatic replenishment mechanism can be triggered to maintain stable system operation.

[0056] It should be noted that in this embodiment, the connected components are all connected by pipes, and valves or instruments can be installed or adjusted on the pipes as needed by those skilled in the art.

[0057] The working principle of this utility model is as follows: The biogas slurry is delivered from the biogas slurry storage tank 40 to the biogas slurry inlet of the hot plate evaporator 10, while 90°C hot water enters the plate flow channel of the hot plate evaporator 10 through the hot water inlet. The biogas slurry forms a thin film on the surface of the hot plate, absorbing heat from the hot water and partially vaporizing the water. After the gas-liquid mixture enters the separator 20, the concentrated liquid is discharged from the bottom outlet, and the steam rises to the top and enters the condenser 50. The circulating cooling water in the condenser 50 exchanges heat with the steam, and the condensate is pumped through pipelines to the top spray system of the separator 20. The spray droplets contact the residual steam, reducing the internal temperature gradient of the separator 20, while simultaneously recovering water to form a closed loop.

[0058] In the description of the embodiments of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0059] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A hot water-hot plate evaporation and concentration system, characterized in that, include: The hot plate evaporation module includes a hot plate evaporator (10) and a separator (20) connected to the hot plate evaporator (10); the hot plate evaporator (10) is provided with a biogas slurry inlet, a hot water inlet, a hot water outlet and a concentrate outlet; the biogas slurry inlet is fed with biogas slurry to be evaporated and concentrated; the hot water inlet is fed with hot water at a first temperature; the hot water outlet discharges hot water at a second temperature; the concentrate outlet discharges liquid after the biogas slurry has been concentrated. The condensation module includes a condenser (50) connected to the separator (20); the condenser (50) is configured to collect the steam discharged from the separator (20) and condense it into liquid water, then spray it into the separator (20) for cooling and to recover the liquid water.

2. The hot water-hot plate evaporation and concentration system according to claim 1, characterized in that, The condensation module also includes an ejector (60) connected to the condenser (50) and a secondary steam condensate tank (70) connected to the ejector (60); the secondary steam condensate tank (70) is equipped with a heat exchanger, the heat exchanger is supplied with circulating water, and the steam collected by the condenser (50) is cooled and condensed into condensate by the circulating water.

3. The hot water-hot plate evaporation and concentration system according to claim 2, characterized in that, The condensation module also includes a secondary steam condensate pump (80) connected to the outlet of the secondary steam condensate tank (70).

4. The hot water-hot plate evaporation and concentration system according to claim 1, characterized in that, The condenser (50) is supplied with circulating cooling water.

5. The hot water-hot plate evaporation and concentration system according to claim 1, characterized in that, The separator (20) is connected to a defoaming module; the defoaming module is configured to reduce the formation of bubbles and foam in the liquid within the separator (20).

6. The hot water-hot plate evaporation and concentration system according to claim 5, characterized in that, The defoaming module includes a foam sensor located in the separator (20) and a defoaming agent tank (90) connected to the hot plate evaporator (10); the defoaming agent tank (90) stores defoaming agent.

7. The hot water-hot plate evaporation and concentration system according to claim 6, characterized in that, The defoamer is one of an acidic solution, an alkaline solution, and hot water.

8. The hot water-hot plate evaporation and concentration system according to claim 1, characterized in that, The hot plate evaporation module also includes a concentrate discharge pump (30) connected to the concentrate outlet of the hot plate evaporator (10).

9. The hot water-hot plate evaporation and concentration system according to claim 1, characterized in that, The first temperature is 90°C; the second temperature is 80°C.

10. The hot water-hot plate evaporation and concentration system according to claim 1, characterized in that, It also includes a biogas slurry storage tank (40) connected to the biogas slurry inlet of the hot plate evaporator (10); the biogas slurry storage tank (40) is configured to store biogas slurry to be evaporated and concentrated.

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