Negative pressure flash evaporation system for livestock and poultry biogas slurry concentration

Abstract

The utility model relates to a negative pressure flash evaporation system for livestock and poultry biogas slurry concentration, which comprises an acid regulation unit, a flash evaporation unit, a flash evaporation unit and a flash evaporation unit, and is characterized in that the acid regulation unit is used for receiving biogas slurry and carrying out acid regulation treatment on the biogas slurry; the first heating unit is connected with the acid adjusting unit so as to receive the biogas slurry subjected to acid adjusting treatment, and the first heating unit is connected with the heat exchange unit so as to receive steam transmitted by the heat exchange unit; the heat exchange unit is connected with the negative pressure flash tank to receive the steam transmitted by the negative pressure flash tank, the heat exchange unit is connected with the first heating unit to receive the biogas slurry transmitted by the first heating unit, and the heat exchange unit is connected with the heating unit to receive the steam transmitted by the heating unit; the negative pressure flash tank is connected with the heat exchange unit so as to receive the biogas slurry transmitted by the heat exchange unit; and the heating unit is used for supplying heat to the heat exchange unit. The negative pressure flash evaporation system reserves nutrient elements of the biogas slurry and realizes concentration of the biogas slurry, and belongs to the technical field of recycling of waste biogas slurry in the livestock and poultry industry.

Description

Technical Field

[0001] The utility model relates to the technical field of resource utilization of waste biogas slurry in livestock and poultry breeding, and in particular to a negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry. Background Art

[0002] With the highly intensive and large-scale development of China's livestock and poultry farming industry in recent years, biogas projects have also been widely used as energy engineering technologies for the development and utilization of livestock and poultry manure. However, while generating clean energy, biogas projects also generate a large amount of waste, of which biogas slurry accounts for more than 80% of the total volume. From the composition of livestock and poultry biogas slurry, it contains a large number of elements such as nitrogen, phosphorus, potassium, a variety of trace elements, proteins, amino acids and biologically active substances, and has the characteristics of high yield, high salinity and high COD. If it is discharged directly, it will cause environmental problems such as soil compaction, eutrophication of water bodies, odor pollution, and also lead to a large amount of water resources and fertility waste. Therefore, a series of environmental problems caused by a large amount of livestock and poultry biogas slurry need to be solved urgently.

[0003] Existing livestock and poultry biogas slurry treatment technologies can be divided into two types according to the treatment methods: harmless treatment and resource utilization. Harmless treatment refers to treating the biogas slurry as high-concentration organic wastewater without utilizing the nutrients in it. After the treatment meets the standards, it is finally discharged into the municipal sewage treatment system. The main technologies include anaerobic aerobic process (A / O), sequencing batch activated sludge process (SBR), membrane bioreactor (MBR), sequencing batch biofilm reactor (SBBR), aerated biological filter (BAF), etc. Among them, the representative AO process, the anaerobic section is used for nitrogen and phosphorus removal, and the aerobic section is used to remove organic matter in the water, ultimately achieving harmless sewage treatment.

[0004] Resource treatment refers to the use of waste livestock and poultry biogas as liquid fertilizer, effectively utilizing a large amount of water-soluble fast-acting elements in the biogas, and ultimately realizing the resource utilization of water and nutrients. Biogas slurry resource technology has made certain progress in recent years. According to the driving force classification, there are three main methods: pressure drive (membrane method), heat drive and electric field drive. Specifically, there are reverse osmosis (RO), membrane distillation (MD), multiple effect evaporation (MED), steam mechanical recompression technology (MVR), electrochemistry (EST) and other technologies. Among them, the representative RO technology uses the selectivity of the membrane, using the static pressure difference on both sides of the membrane as the driving force to overcome the osmotic pressure of the solvent, allowing the solvent to pass through and intercepting ionic substances to achieve the purpose of separation. MVR is to use the energy of the secondary steam generated by itself in a micro-vacuum state to upgrade the low-grade steam into a high-grade steam heat source through the mechanical work of the compressor, so as to circulate and supply energy to the evaporation system, thereby achieving the purpose of low-consumption concentration, and ultimately realizing the resource utilization of water and nutrients.

[0005] Due to the characteristics of biogas slurry itself, intensive farms currently use harmless treatment or composting-dilution and field return methods to treat waste biogas slurry. Harmless treatment technology treats livestock and poultry biogas slurry as organic waste liquid for standard treatment, which essentially wastes a large amount of fast-acting nutrients and water resources, and increases the treatment pressure of municipal sewage pipe networks. Judging from the actual treatment effects of various harmless technologies, a single technology often cannot meet the standards. For example, the AO process has problems such as a low reduction rate for organic pollution sources. Usually, a combination of multiple technical units is required to achieve the effective removal of pollution sources such as nitrogen, phosphorus and organic matter. The complex composition of biogas slurry increases the difficulty of treatment technology. The combination of different technical units requires a large site construction area and high construction and maintenance costs. Some units also require the addition of a large amount of chemical / biological agents, and the final end water can meet the relevant emission standards.

[0006] The representative membrane method in resource recovery technology has a large number of application cases in many industries, but it is difficult to apply it on a large scale in biogas slurry treatment. Taking the RO method as an example, the pore size of its membrane surface is generally less than 1nm, and it has an ideal removal rate for most inorganic salts, dissolved organic matter, etc., but it has a high pressure requirement and needs to select a high-cost, high-permeability, high-selectivity semipermeable membrane. In addition, a large amount of salt in the biogas slurry precipitates and scales on the membrane surface due to the increase in unit concentration during the treatment process, resulting in a sharp decline in the life of the membrane. Frequent replacement of the membrane requires a high economic cost, which ultimately limits the scope of application of this method. Although MVR in thermal drive technology has the advantages of good concentration effect and significant reduction, in addition to the disadvantages of large construction site area and easy corrosion of equipment, there are also serious nitrogen losses in the biogas evaporation process, and environmental problems such as odor pollution caused by nitrogen escape. Due to the problems of low current efficiency in actual operation of EST technology, most electric field drive technologies are still in the indoor test stage and are still far from industrial application. In addition, the currently more common method of returning manure to fields on site is often restricted by factors such as the low degree of manure maturity, seasonal fertilization of farmland, and limited area of ​​surrounding farmland. It is also difficult to absorb the large amount of manure continuously produced by intensive farms.

[0007] In summary, the main contradictions in the resource utilization of biogas slurry are concentrated in the following aspects: first, the output of biogas slurry is large, but the amount of soil absorption in the nearby fields is limited; the economic cost of long-distance utilization is high and the feasibility is poor; second, nitrogen is easily lost during the utilization of biogas slurry, which brings about environmental problems such as odor pollution; third, there is a contradiction between the continuous production of biogas slurry and the seasonal fertilization demand of farmland. Utility Model Content

[0008] In view of the technical problems existing in the prior art, the purpose of the utility model is to provide a negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry, so as to solve the problems of nutrient element loss, large processing area and low actual processing efficiency in the existing livestock and poultry biogas slurry resource utilization technology.

[0009] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0010] A negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry comprises: an acid conditioning unit, used for receiving biogas slurry and performing acid conditioning treatment on the biogas slurry; a first temperature rising unit, which is connected to the acid conditioning unit to receive the biogas slurry after the acid conditioning treatment, and is connected to a heat exchange unit to receive steam transmitted by the heat exchange unit; a heat exchange unit, which is connected to a negative pressure flash tank to receive steam transmitted by the negative pressure flash tank, and is connected to the first temperature rising unit to receive biogas slurry transmitted by the first temperature rising unit, and is connected to a heating unit to receive steam transmitted by the heating unit; a negative pressure flash tank, which is connected to the heat exchange unit to receive biogas slurry transmitted by the heat exchange unit; and a heating unit, which is used for supplying heat to the heat exchange unit.

[0011] As a preferred embodiment, the acid adjustment unit includes a centrifugal pump and an acid adjustment tank. The centrifugal pump is used to pump the biogas slurry to the acid adjustment tank. The acid adjustment tank is provided with a stirring device and an acid adding port. An acid adding component is installed at the acid adding port. The stirring device is arranged in the acid adjustment tank. The acid adjustment tank is also provided with an exhaust hole for exhausting the gas generated by the reaction.

[0012] As a preferred embodiment, the acid adding component includes a funnel and a flow regulating valve, the funnel is installed at the acid adding port, and the flow regulating valve is arranged at the liquid outlet end of the funnel.

[0013] As a preferred embodiment, the first heating unit includes a heat exchange barrel and a heat pipe, the heat exchange barrel is connected to the acid adjustment tank to receive the acid-adjusted biogas slurry, the heat pipe is arranged in the heat exchange barrel, and the heat pipe is connected to the heat exchange unit to receive the steam transmitted by the heat exchange unit.

[0014] As a preference, the heat exchange unit includes a first heat exchanger and a second heat exchanger, the first heat exchanger is connected to the second heat exchanger to receive steam transmitted by the second heat exchanger, the first heat exchanger is connected to the negative pressure flash tank to receive steam transmitted by the negative pressure flash tank, and the first heat exchanger is connected to the heat exchange barrel to receive the biogas slurry in the heat exchange barrel; the second heat exchanger is connected to the heating unit to receive the steam transmitted by the heating unit, the second heat exchanger is connected to the first heat exchanger to receive the biogas slurry transmitted by the first heat exchanger, and the second heat exchanger is connected to the negative pressure flash tank to transmit the biogas slurry to the negative pressure flash tank.

[0015] As a preference, an atomizer is provided at the inlet of the negative pressure flash tank, the inlet of the atomizer is connected to the second heat exchanger to receive the biogas slurry transmitted by the second heat exchanger, and the outlet of the atomizer is connected to the inlet of the negative pressure flash tank.

[0016] As a preference, the negative pressure flash tank is provided with a steam outlet, the steam outlet is connected to a steam delivery pipeline, the steam delivery pipeline is connected to a steam pump, and the steam pump is connected to the first heat exchanger.

[0017] As a preferred embodiment, the negative pressure flash tank is provided with a concentrated liquid outlet, and a concentrated liquid solenoid valve is provided at the concentrated liquid outlet; a raw liquid solenoid valve and a three-way valve are sequentially provided on the connecting channel between the heat exchange barrel and the first heat exchanger, the concentrated liquid solenoid valve is connected to the raw liquid solenoid valve and the three-way valve, and the three-way valve is connected to a concentrated liquid collection container.

[0018] Preferably, the heating unit comprises a solar thermal converter, and the solar thermal converter is connected to the second heat exchanger.

[0019] Preferably, the heating unit further comprises an electric steam generator, which is connected to the second heat exchanger.

[0020] In general, the utility model has the following advantages:

[0021] 1. The utility model adopts pretreatment acid adjustment technology, and promotes chemical balance by changing the pH value of biogas slurry, so that the biogas slurry moves in the direction of forming more ammonium ions to achieve the purpose of retaining nutrients. The negative pressure flash evaporation system of the utility model can effectively complete the biogas slurry concentration, and the precise control of biogas slurry reduction can be achieved through multiple cycles. The ammonia nitrogen content of the condensed water also meets the relevant standards, and more nitrogen is effectively retained in the concentrated liquid as a nutrient element, which solves the problems of nutrient element loss, large processing volume and low actual processing efficiency in the existing livestock and poultry biogas resource utilization technology.

[0022] 2. The utility model adopts green energy - solar energy to provide thermal energy, and utilizes the gas-liquid two-phase conversion of biogas slurry to form a low negative pressure environment, thus solving the problem of high energy consumption and high cost of biogas slurry treatment.

[0023] 3. The utility model realizes the cyclic concentration of biogas slurry and the continuous operation through the pipeline design of condensate and concentrated liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of negative pressure flash evaporation system.

[0025] In the figure, 1-slurry storage tank; 2-centrifugal pump; 3-acid adjustment tank; 4-heat exchange barrel; 5-raw liquid solenoid valve; 6-three-way valve; 7-first heat exchanger; 8-second heat exchanger; 9-atomizer; 10-negative pressure flash tank; 11-concentrate solenoid valve; 12-concentrate collection container; 13-clear water hopper; 14-solar thermal converter; 15-electric steam generator; 16-drain valve; 17-condensate collection container; 18-steam pump. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below in conjunction with specific implementation methods.

[0027] Compared with the existing methods for solving the problems of livestock and poultry biogas slurry, the present invention starts from the resource utilization idea, takes into account factors such as nutrient retention, high efficiency and low consumption, and resource utilization, and provides a negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry. The purpose of the present invention is to solve the problems of nutrient element loss, large processing volume, and low actual processing efficiency in the existing livestock and poultry biogas resource utilization technology. Based on the thermodynamic Antoine equation and the Clausius-Clapeyron equation, a negative pressure flash evaporation system that can be concentrated in multiple cycles is designed, and an acid adjustment unit is designed to retain nutrient elements, ultimately achieving low-consumption and high-efficiency resource utilization of livestock and poultry biogas slurry, and providing a new solution for the "low-consumption treatment and high-value utilization" resource treatment mode of waste biogas generated by large-scale livestock and poultry breeding.

[0028] like Figure 1 As shown, the negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry provided in this embodiment specifically includes an acid adjustment unit (which can be an existing dripper to add acid to the biogas slurry), a heating unit (which can be a solar thermal converter, an electric steam generator or other equipment that can heat the biogas slurry), a first heating unit (which can be formed by a bucket plus an electric heating tube), a heat exchange unit (which can be an existing plate heat exchanger or other equipment that can heat the biogas slurry without direct contact), an atomizer, and a negative pressure flash tank. The negative pressure flash evaporation system is shown in FIG. Figure 1 . By adopting the negative pressure flash evaporation technology, the acid of the biogas slurry is first adjusted through the acid adjustment unit, and then the biogas slurry is heated for the first time by the first heating unit after the acid adjustment unit, and then the biogas slurry is pumped into the heat exchange unit for secondary heating. When the temperature reaches a certain value, it is sprayed into the negative pressure flash tank after atomization by the atomizer. At the same time, a large amount of gas is liquefied, the pressure is reduced, and negative pressure is generated in the negative pressure flash tank to achieve the purpose of negative pressure flash evaporation. The volume of biogas slurry is effectively reduced in a short time to achieve biogas slurry concentration. In addition, the negative pressure flash evaporation system is also designed with a concentrated liquid circulation flash evaporation structure. For example, a pipeline is set at the outlet of the negative pressure flash tank to transport the concentrated liquid output from the negative pressure flash tank back to the heat exchange unit for heat exchange again, and then transported from the heat exchange unit to the negative pressure flash tank for negative pressure flash evaporation again to meet different concentration requirements. The steam produced by the negative pressure flash evaporation system is condensed to form condensed water, which can be reused on the spot, and the concentrated liquid can be used as biogas fertilizer for resource utilization.

[0029] Specific examples:

[0030] The acid adjustment unit includes a centrifugal pump 2 and an acid adjustment tank 3. The acid adjustment tank 3 is designed with a stirring device (which can be an existing vertical mixer), an exhaust hole and an acid addition port. The centrifugal pump 2 is used to pump biogas from the biogas storage tank 1 of the livestock and poultry farm into the acid adjustment tank 3. When the biogas reaches a certain liquid level, the exhaust hole above the acid adjustment tank 3 is opened to discharge the gas that may be generated during acid addition. The stirring motor of the stirring device is turned on. After the stirring motor speed is stable, the funnel on the top of the acid adjustment tank 3 is opened to slowly drip acid (such as sulfuric acid, phosphoric acid, other types or mixed acids) from the acid addition port to adjust the pH value of the biogas. The dripping amount can be appropriately adjusted according to different target pH values. The adjustment method is to maintain a stable dripping speed and stirring speed through a flow control valve set at the liquid outlet of the funnel until the pH value of the biogas is adjusted to meet the requirements, and then the strong acid resistant valve of the acid adjustment tank 3 is opened. The strong acid resistant valve of the acid adjustment tank 3 is set at the outlet of the acid adjustment tank 3, and the biogas after acid adjustment enters the heat exchange barrel 4 through the outlet of the acid adjustment tank 3. The acid adjustment unit can achieve precise control of the pH value of the biogas slurry, appropriately increase the biogas slurry temperature (the principle is that the acid will generate a certain amount of heat after entering the water, which will lead to an increase in the biogas slurry temperature), push the nitrogen balance to move towards the direction of generating ammonium ions, effectively retain a large amount of nitrogen in the biogas slurry, and avoid the negative effects such as sudden pressure rise, odor pollution and cavitation that may occur in the subsequent flash concentration process. Through the above scheme, the biogas slurry from the livestock and poultry farm can be continuously concentrated by continuously transporting the biogas slurry from the livestock and poultry farm to the negative pressure flash system for concentration, without occupying a large area for biogas slurry treatment, and the treatment efficiency is high.

[0031] The first heating unit includes a heat exchange barrel and a heat pipe. The heat pipe has an inner and outer double helix structure. The heat pipe is built into the heat exchange barrel 4. The barrel body is used to receive the biogas slurry after acidification. The principle of the first heating unit is to use steam waste heat (after the subsequent heat exchange unit heats the biogas slurry for the second time, the steam is transferred to the heat pipe. The steam waste heat includes the steam provided by the heating unit and the steam provided by the negative pressure flash tank) to heat the biogas slurry for the first time. The steam flows inside the heat pipe with a double helix structure. The steam condenses into liquid after passing through the heat pipe. After condensing into liquid, it is transferred to the condensate collection container 17. The specific setting of the condensate collection container 17 is shown below. The biogas slurry after acidification is temporarily stored between the heat pipe with a double helix structure and the barrel body. After the first heating is completed, the original liquid solenoid valve 5 is opened.

[0032] The heat exchange unit includes a first heat exchanger 7 and a second heat exchanger 8, which are mainly used for heat exchange between biogas slurry and superheated steam after the first heating. The steam in the first heat exchanger 7 is a mixed steam after flash evaporation and the second heat exchanger 8, so as to achieve the maximum utilization efficiency of thermal energy. The steam in the second heat exchanger 8 is the superheated steam generated by the solar thermal converter 14 and / or the electric steam generator 15, and the temperature of this steam is the highest in the entire system. The two fluids (biogas slurry and steam) are divided into different pipelines inside the first heat exchanger 7 and the second heat exchanger 8, and only heat is exchanged without actual contact. The heat energy of the superheated steam in the first heat exchanger 7 and the second heat exchanger 8 is efficiently exchanged to the biogas slurry after the first heating and acid adjustment, so as to achieve the second heating of the biogas slurry for flash evaporation concentration. After the steam of the first heat exchanger 7 and the second heat exchanger 8 completes the heat exchange, it enters the steam trap 16 and is then transmitted to the heat pipe in the heat exchange barrel.

[0033] The negative pressure flash tank 10 is provided with an atomizer 9. Specifically, an inlet for receiving biogas slurry is provided in the middle of the negative pressure flash tank 10, and the atomizer 9 is connected to the inlet for receiving biogas slurry. After heat exchange in the heat exchange unit, the biogas slurry first enters the atomizer 9, and the atomizer 9 forms the biogas slurry into fine water droplets to improve the concentration efficiency. The biogas slurry is sprayed into the negative pressure flash tank 10 after being atomized. Under the negative pressure and high temperature conditions, a part of the water is separated from the biogas slurry to form water vapor; the negative pressure flash tank 10 is provided with a steam outlet, and the steam outlet is located at the top of the negative pressure flash tank. The water vapor is pumped to the first heat exchanger 7 through the steam pump 18 connected to the steam outlet at the top of the negative pressure flash tank 10, and the biogas slurry with a part of the water evaporated forms a concentrated liquid.

[0034] The negative pressure flash tank is provided with a concentrated liquid outlet, which is specifically located at the bottom of the negative pressure flash tank, so as to facilitate the discharge of all the concentrated liquid from the negative pressure flash tank; a concentrated liquid solenoid valve 11 is provided at the concentrated liquid outlet; a raw liquid solenoid valve 5 and a three-way valve 6 are sequentially arranged on the connecting channel between the heat exchange barrel and the first heat exchanger, and the concentrated liquid solenoid valve 11 is connected to the raw liquid solenoid valve 5 and the three-way valve 6, and the three-way valve is connected to a concentrated liquid collection container.

[0035] The concentrated biogas slurry is concentrated at the bottom of the negative pressure flash tank 10, and the concentrated biogas slurry can be circulated or collected for multiple times by controlling the concentrated liquid solenoid valve 11. The flash evaporation technology is used to achieve rapid concentration of biogas slurry in a low vacuum environment, and the circulating concentration system formed by the cooperation of the raw liquid solenoid valve 5, the concentrated liquid solenoid valve 11 and the three-way valve 6 can flexibly control the different concentration levels of biogas slurry, so as to achieve low-consumption and high-efficiency resource utilization of biogas slurry.

[0036] Circulation and concentration system: the raw liquid solenoid valve 5, the concentrated liquid solenoid valve 11 and the three-way valve 6 are used for the on-off operation of the concentrated liquid circulation. When circulation is not required, open the raw liquid solenoid valve 5, open the concentrated liquid solenoid valve 11, and adjust the three-way valve 6 to allow the concentrated liquid to directly enter the biogas slurry collection container 12. When circulation and concentration are required, after a sufficient amount of biogas slurry to be concentrated enters the system, close the raw liquid solenoid valve 5, open the concentrated liquid solenoid valve 11, and adjust the three-way valve to allow the concentrated liquid to enter the first heat exchanger 7. Then the biogas slurry transportation route is heat exchange unit-negative pressure flash tank-concentrated liquid solenoid valve-three-way valve-heat exchange unit circulation. Through the operation of this part, it is possible to achieve precise control of whether to carry out biogas slurry concentration circulation and the number of cycles (target concentration multiples of biogas slurry).

[0037] The negative pressure flash evaporation system also includes a clean water bucket 13. When the negative pressure flash evaporation system is first operated, tap water can be added as a heat exchange medium, and the condensate formed by the condensation of steam after flash evaporation can be used later. In this embodiment, the clean water bucket 13 is set to store the heat exchange medium. For example, when the clean water is added to a certain amount, the valve of the clean water bucket 13 can be opened, and the clean water enters the solar thermal converter 14 for heating, so that the clean water forms water vapor; the clean water bucket is connected to the solar thermal converter 14 through a pipeline, and the clean water bucket is connected to the condensate collection container 17 through a pipeline to form a condensate water circulation structure, in which the clean water in the clean water bucket is in a liquid state-the clean water in the solar thermal converter 14 is converted from liquid to steam and transmitted to the heat exchange unit-the heat exchange unit exchanges heat with the biogas slurry and then transmits the steam to the steam trap-the steam is transported to the heat transfer pipe in the heat exchange barrel through the steam trap-the heat transfer pipe exchanges heat with the biogas slurry to convert the steam into liquid-the liquid enters the condensate collection container-the liquid is transmitted from the condensate collection container to the clean water bucket to form a condensate water circulation structure. There is also a liquid conversion structure, which is specifically as follows: the steam generated by the negative pressure flash tank is transported to the heat exchange unit - the heat exchange unit transports this part of the steam to the steam trap - the steam is transported to the heat pipe in the heat exchange barrel through the steam trap - the heat pipe exchanges heat with the biogas slurry to convert the steam into liquid - the liquid enters the condensate collection container - the liquid is transmitted from the condensate collection container to the clean water hopper to form a liquid conversion structure.

[0038] The upper part of the solar thermal converter 14 is a heat-absorbing copper tube, and the lower part is a sunlight curved reflective mirror. The solar thermal converter is used to heat water and generate steam. After passing through this curved surface, the sunlight is concentrated and reflected on the upper pipe to achieve the temperature increase of the clean water in the pipe. After the temperature increase, the liquid phase of the water can be converted into the gas phase. The angle of the photothermal converter can be adjusted according to the angle of sunlight to achieve the maximum utilization efficiency of green energy.

[0039] The electric steam generator 15 is equipped with a temperature and pressure gauge in addition to the electric heating equipment. The electric steam generator 15 is only used as a substitute for the solar thermal converter 14 and is only used under certain specific conditions (such as rainy days). It will not be introduced in detail here. After the clean water passes through the solar thermal converter 14 and the electric steam generator 15 to become superheated steam, it enters the second heat exchanger 8 and the first heat exchanger 7 for heat exchange.

[0040] After the steam comes out of the second heat exchanger 8 and the first heat exchanger 7, it enters the heat transfer pipe in the heat exchange barrel 4 through the steam trap 16 to continue heat exchange and complete liquefaction at the same time.

[0041] The condensate collection container is connected to the clean water bucket with a pipeline to realize the reuse of condensate. The condensate collection container is used to receive the liquefied condensate in the heat transfer pipe, and then transfer the liquid to the clean water bucket for continued circulation as needed.

[0042] The steam pump 18 is used to pump the steam flashed out of the negative pressure flash tank into the heat exchanger 7, and also provides a greater negative pressure for the negative pressure flash tank.

[0043] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry, characterized in that: include: An acid conditioning unit, used for receiving biogas slurry and performing acid conditioning treatment on the biogas slurry; A first heating unit, the first heating unit is connected to the acid conditioning unit to receive the biogas slurry after acid conditioning, and the first heating unit is connected to the heat exchange unit to receive the steam transmitted by the heat exchange unit; A heat exchange unit, the heat exchange unit is connected to the negative pressure flash tank to receive steam transmitted by the negative pressure flash tank, the heat exchange unit is connected to the first heating unit to receive biogas slurry transmitted by the first heating unit, and the heat exchange unit is connected to the heating unit to receive steam transmitted by the heating unit; A negative pressure flash tank, which is connected to the heat exchange unit to receive the biogas slurry transmitted by the heat exchange unit; The heating unit is used to supply heat to the heat exchange unit.

2. A negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry according to claim 1, characterized in that: The acid conditioning unit includes a centrifugal pump and an acid conditioning tank. The centrifugal pump is used to pump the biogas slurry to the acid conditioning tank. The acid conditioning tank is provided with a stirring device and an acid adding port. An acid adding component is installed at the acid adding port. The stirring device is arranged in the acid conditioning tank. The acid conditioning tank is also provided with an exhaust hole for discharging the gas generated during the biogas slurry acid conditioning process.

3. A negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry according to claim 2, characterized in that: The acid adding component comprises a funnel and a flow regulating valve. The funnel is installed at the acid adding port, and the flow regulating valve is arranged at the liquid outlet end of the funnel.

4. A negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry according to claim 2, characterized in that: The first heating unit includes a heat exchange barrel and a heat pipe. The heat exchange barrel is connected to the acid adjustment tank to receive the acid-adjusted biogas slurry. The heat pipe is arranged in the heat exchange barrel and connected to the heat exchange unit to receive the steam transmitted by the heat exchange unit.

5. A negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry according to claim 4, characterized in that: The heat exchange unit includes a first heat exchanger and a second heat exchanger, the first heat exchanger is connected to the second heat exchanger to receive steam transmitted by the second heat exchanger, the first heat exchanger is connected to the negative pressure flash tank to receive steam transmitted by the negative pressure flash tank, and the first heat exchanger is connected to the heat exchange barrel to receive the biogas slurry in the heat exchange barrel; the second heat exchanger is connected to the heating unit to receive steam transmitted by the heating unit, the second heat exchanger is connected to the first heat exchanger to receive biogas slurry transmitted by the first heat exchanger, and the second heat exchanger is connected to the negative pressure flash tank to transmit the biogas slurry to the negative pressure flash tank.

6. A negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry according to claim 5, characterized in that: An atomizer is provided at the inlet of the negative pressure flash tank, the inlet of the atomizer is connected to the second heat exchanger to receive the biogas slurry transmitted by the second heat exchanger, and the outlet of the atomizer is connected to the inlet of the negative pressure flash tank.

7. A negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry according to claim 6, characterized in that: The negative pressure flash tank is provided with a steam outlet, the steam outlet is connected to a steam delivery pipeline, the steam delivery pipeline is connected to a steam pump, and the steam pump is connected to the first heat exchanger.

8. A negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry according to claim 7, characterized in that: The negative pressure flash tank is provided with a concentrated liquid outlet, and a concentrated liquid solenoid valve is provided at the concentrated liquid outlet; a raw liquid solenoid valve and a three-way valve are sequentially provided on the connecting channel between the heat exchange barrel and the first heat exchanger, the concentrated liquid solenoid valve is connected to the raw liquid solenoid valve and the three-way valve, and the three-way valve is connected to a concentrated liquid collection container.

9. A negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry according to claim 5, characterized in that: The heating unit comprises a solar photothermal converter, which is connected to the second heat exchanger.

10. A negative pressure flash evaporation system for concentrating livestock and poultry biogas slurry according to claim 9, characterized in that: The heating unit further comprises an electric steam generator, which is connected to the second heat exchanger.

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