Biomass treatment device system and method based on carbon source internal circulation

Abstract

The invention provides a biomass treatment device system and method based on carbon source internal circulation. The biomass treatment device system comprises a waste biomass pretreatment unit, a biogas slurry generation unit, a biogas slurry treatment unit and an internal carbon source preparation unit, one path of the waste biomass pretreatment unit is sequentially connected with the biogas slurry generation unit and the biogas slurry treatment unit, and the other path of the waste biomass pretreatment unit is connected to the biogas slurry treatment unit through the internal carbon source preparation unit. According to the device system, carbon source preparation is introduced into a waste biomass treatment system, waste biomass is decomposed and converted, a high-quality internal carbon source is formed and used for biogas slurry treatment, rich carbon sources in the waste biomass are efficiently utilized, high-price outsourcing of commercial carbon sources is not needed, and compared with a conventional commercial carbon source, the activity of the biogas slurry can be improved, and the production cost is reduced. Meanwhile, the utilization rate of a carbon source is increased, and the process cost of the system is reduced.

Description

Technical Field

[0001] This invention belongs to the field of biomass utilization technology, specifically relating to a biomass treatment device system and method based on internal carbon source circulation. Background Technology

[0002] In the field of waste biomass resource utilization, organic waste, represented by kitchen waste (including catering waste, household kitchen waste, and other easily perishable organic waste, hereinafter the same), municipal sludge, and fecal waste, typically employs anaerobic digestion technology to convert organic matter into biogas, achieving resource recovery. Among these processes, biogas slurry, as the main byproduct of anaerobic digestion, has always presented a significant technical challenge. Biogas slurry is a complex, high-concentration wastewater characterized by high concentrations of organic matter and ammonia nitrogen, but with a significantly low effective carbon-to-nitrogen ratio (C / N). This water quality characteristic leads to an inherent deficiency in the carbon source structure during the essential subsequent biochemical treatment process, especially denitrification, resulting in low denitrification efficiency and difficulty in consistently meeting environmental emission standards for effluent nitrogen levels.

[0003] Currently, the industry commonly uses the method of continuously adding purchased commercial carbon sources, such as methanol, sodium acetate, or glucose, to the biogas slurry treatment system to adjust the carbon-to-nitrogen ratio of the biogas slurry and improve denitrification efficiency. However, this model has certain contradictions. In anaerobic digestion processes, a large amount of carbon contained in biomass is converted into biogas, but the digested biogas slurry cannot meet the requirements for deep treatment due to the imbalance of the carbon-to-nitrogen ratio, forcing the process to rely on expensive purchased carbon sources.

[0004] The contradiction between the difficulty in fully utilizing this carbon source and the high operating costs of the process has become a bottleneck restricting the sustainable development of biomass treatment. Summary of the Invention

[0005] The purpose of this invention is to provide a biomass treatment device system and method based on internal carbon source circulation, which realizes the direct conversion of waste biomass into an internal carbon source for biogas slurry treatment, thereby improving carbon source utilization and biogas slurry treatment efficiency.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a biomass treatment device system based on internal carbon source circulation, the biomass treatment device system comprising: Waste biomass pretreatment unit, biogas slurry generation unit, biogas slurry treatment unit, and internal carbon source preparation unit; One path of the waste biomass pretreatment unit is connected in sequence to the biogas slurry generation unit and the biogas slurry treatment unit, and the other path of the waste biomass pretreatment unit is connected to the biogas slurry treatment unit via the internal carbon source preparation unit.

[0007] The device system provided by this invention introduces carbon source preparation into the waste biomass treatment system, realizing the decomposition and transformation of waste biomass into a high-quality internal carbon source that is easy to utilize efficiently. This internal carbon source is used to supplement the carbon source in biogas slurry treatment, making efficient use of the abundant carbon source in waste biomass without the need to purchase expensive commercial carbon sources. Furthermore, compared with conventional commercial carbon sources, the internal carbon source converted from waste biomass has a certain salt content, which can enhance the activity of biogas slurry, promote the denitrification and phosphorus removal effect of microorganisms in biogas slurry, improve the biogas slurry treatment effect, improve the carbon source utilization efficiency, and reduce the system process cost.

[0008] Preferably, the internal carbon source preparation unit includes a carbon source preparation tank and a sieving device.

[0009] Preferably, the carbon source preparation tank includes a tank body, with a stirrer arranged axially along the center of the tank body and a heat exchange coil spirally arranged along the inner side of the tank body.

[0010] A stirrer is installed in the tank for continuous stirring during carbon source preparation. The heat exchange coil is arranged in a ring around the inner wall of the tank and can be supplied with water for temperature control during the carbon source preparation process.

[0011] Preferably, a detection device is provided on the side of the tank for real-time detection of the slurry inside the tank.

[0012] Preferably, the detection device includes an online COD analyzer, a pH meter, a level gauge, and a thermometer.

[0013] The tank is equipped with a detection device for real-time monitoring of the slurry inside, ensuring that the slurry parameters meet standards and guaranteeing the efficiency of carbon source preparation. This detection device can be linked to the valves in the system for control, adjusting valve opening and closing based on changes in slurry parameters to replenish material in the tank.

[0014] Preferably, the screening device includes a multi-stage vibrating screen.

[0015] Preferably, the biogas slurry generating unit is connected to the carbon source preparation tank for recycling the biogas slurry to the carbon source preparation tank.

[0016] The recycled biogas slurry is used to replenish the alkalinity of the slurry in the tank and to provide trace amounts of dissolved oxygen.

[0017] Preferably, the biogas slurry generating unit includes a hydrolysis acidification tank, an anaerobic fermentation tank, and a biogas slurry conditioning and dehydration device connected in sequence.

[0018] Preferably, the biogas slurry conditioning and dewatering device includes a conditioning tank and a high-pressure diaphragm filter press.

[0019] Preferably, the biogas slurry treatment unit is equipped with an ultrafiltration device, which is connected to an internal carbon source preparation unit for sludge reuse.

[0020] Secondly, the present invention provides a biomass treatment method based on internal carbon source circulation, wherein the biomass treatment method uses the biomass treatment device system based on internal carbon source circulation described in the first aspect.

[0021] Preferably, the biomass treatment method includes the following steps: (1) The waste biomass is pretreated in the waste biomass pretreatment unit to form organic slurry; (2) The organic slurry is processed in the biogas production unit to form biogas, biogas slurry and biogas residue; (3) Take a portion of the organic slurry and inoculate it with functional bacteria for biomass decomposition in the internal carbon source preparation unit to convert it into a carbon source, and finally obtain the finished carbon source. (4) Add the obtained finished carbon source to the obtained biogas slurry to supplement the carbon source, and then perform biochemical treatment on the biogas slurry in the biogas slurry treatment unit; Steps (2) and (3) are not in any particular order.

[0022] The waste biomass includes, but is not limited to, kitchen waste, municipal biochemical sludge, or fecal matter.

[0023] Preferably, the solid content of the organic slurry in step (1) is 6%-12%, for example, it can be 6%, 8%, 10% or 12%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, the solid particle size in the organic slurry in step (1) is ≤10mm.

[0025] Preferably, the oil content of the organic slurry in step (1) is ≤5000mg / L.

[0026] Preferably, the treatment in step (2) includes hydrolysis acidification, anaerobic fermentation, conditioning and dehydration in sequence.

[0027] Preferably, the pH of the hydrolysis acidification is controlled at 3-4, for example, it can be 3, 3.2, 3.5, 3.8 or 4, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, the hydrolysis acidification temperature is 25-40℃, for example, it can be 25℃, 30℃, 35℃ or 40℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the hydrolysis and acidification time is 2-3 days, for example, 2 days, 2.5 days or 3 days.

[0030] Preferably, the pH of the anaerobic fermentation is controlled at 7.2-8.2, for example, it can be 7.2, 7.5, 7.8, 8 or 8.2, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Preferably, the temperature of the anaerobic fermentation is 36-39°C, for example, 36°C, 37°C, 38°C or 39°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] Preferably, during the anaerobic fermentation, stirring is maintained, and the power density of the stirring is ≥3.3W / m³. 3 .

[0033] Preferably, in the anaerobic fermentation, the total solids content of the slurry is controlled to be ≤3.0%.

[0034] Preferably, in the anaerobic fermentation, the volatile solids content of the slurry is controlled to be ≤52%.

[0035] Preferably, in the anaerobic fermentation, the concentration of volatile organic acids in the slurry is controlled to be ≤1000mg / L.

[0036] Preferably, in the anaerobic fermentation, the oil content of the slurry is controlled to be ≤500mg / L.

[0037] Preferably, the conditioning agents used in the conditioning include iron salts and / or cationic polyacrylamide.

[0038] Preferably, the iron salt comprises FeCl3.

[0039] Preferably, the amount of iron salt used is 3%-6% of the total dry dissolved solids in the digestive fluid to be prepared, for example, it can be 3%, 4%, 5% or 6%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0040] Preferably, the amount of cationic polyacrylamide used is 0.3%-0.6% of the total dissolved solids dry in the digestion solution to be prepared, for example, it can be 0.3%, 0.4%, 0.5% or 0.6%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0041] Preferably, the dehydration method is high-pressure diaphragm filtration.

[0042] Preferably, the moisture content of the biogas residue obtained by dehydration is ≤65%.

[0043] Preferably, the suspended solids content of the biogas slurry obtained by dehydration is ≤5000mg / L.

[0044] In this invention, high-pressure diaphragm filtration is used to dehydrate and obtain biogas residue and biogas slurry. Compared with conventional centrifugal dehydration, the resulting biogas residue has a lower water content and the biogas slurry has a lower suspended solids content. Using this method, the resulting biogas residue is more suitable for external delivery as raw material for organic fertilizer, and the biogas slurry is less likely to affect the equipment during carbon source preparation and biochemical treatment, which is conducive to the overall stable operation of the system.

[0045] Preferably, the inoculation method includes inoculating activated sludge with functional microbial communities and / or microbial agents with functional microbial communities.

[0046] Preferably, the activated sludge comprises sludge settled in the secondary sedimentation tank of the aerobic process in a municipal wastewater treatment plant.

[0047] Preferably, the method for inoculating the activated sludge includes: diluting the activated sludge to a solid content of more than 10%, and then inoculating it into the carbon source conversion container in the internal carbon source preparation unit to reach more than 1 / 3 of the effective volume of the container.

[0048] Preferably, the functional microbial community includes macromolecule decomposing functional bacteria and small molecule acidifying functional bacteria.

[0049] Preferably, the macromolecular decomposing bacteria include Bacillus and / or Clostridium.

[0050] Preferably, the small molecule acidifying functional bacteria include at least one of Lactobacillus, Bifidobacterium, or Bacteroides.

[0051] In this invention, two types of functional bacteria work synergistically. Macromolecular decomposition bacteria can decompose macromolecular organic matter in organic slurry into small soluble substances such as glucose and amino acids by secreting extracellular enzymes. Small molecule acidifying bacteria further decompose the small soluble substances obtained from decomposition into volatile organic acids. Thus, the macromolecular organic matter in organic slurry is gradually degraded into short-chain, easily degradable small molecule carbon sources, which serve as high-quality carbon sources for denitrification. Volatile organic acids can directly penetrate the cell membrane of denitrifying bacteria without a complex degradation process, resulting in high electron transfer efficiency and a significantly improved denitrification rate.

[0052] Preferably, during the carbon source conversion, continuous stirring is maintained, and the power density of the stirring is ≥5W / m³. 3 .

[0053] Preferably, in the carbon source conversion, the dissolved oxygen concentration of the organic slurry is controlled to be <1 mg / L.

[0054] Preferably, in the carbon source conversion, the pH of the organic slurry is controlled to be 5.0-6.5 by adding the biogas slurry produced in step (2). For example, it can be 5.0, 5.3, 5.5, 5.8, 6.0, 6.2 or 6.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0055] In this invention, by continuously recirculating biogas slurry into the carbon source conversion process, alkalinity is replenished to the carbon source conversion process, thereby achieving pH control of the organic slurry. Simultaneously, under the influence of the recirculated biogas slurry, the pH within the carbon source preparation tank fluctuates, causing macromolecular decomposition bacteria and small-molecule acidifying bacteria to alternately operate within their optimal activity ranges. Through the synergistic metabolic action of these two types of bacteria, the efficiency of organic matter hydrolysis and acidification is maximized.

[0056] Preferably, in the carbon source conversion, the residence time of the organic slurry is 3-15 days, for example, 3 days, 5 days, 8 days, 10 days, 12 days or 15 days.

[0057] Preferably, the carbon source conversion process is completed when the VFA / COD ratio in the organic slurry is ≥10%, or the VFA (volatile organic acid content) is ≥10000 mg / L.

[0058] Preferably, after the carbon source conversion is completed, the resulting slurry is screened.

[0059] Preferably, the mesh size of the last stage of sieving is ≥70 mesh.

[0060] Preferably, in step (4), the COD / NH3 ratio of the finished carbon source added to the biogas slurry is (3.8-5.5):1, for example, it can be 3.8:1, 3.9:1, 4:1, 4.1:1, 4.2:1, 4.5:1, 4.8:1, 5:1, 5.2:1 or 5.5:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0061] Preferably, the biochemical treatment in step (4) includes nitrification, denitrification and membrane bioreactor treatment.

[0062] Preferably, in the biochemical treatment of step (4), the biogas slurry is subjected to ultrafiltration treatment to separate activated sludge, which is then reused for the carbon source conversion.

[0063] Compared with the prior art, the present invention has the following beneficial effects: The device system provided by this invention introduces carbon source preparation into the waste biomass treatment system, realizing the decomposition and transformation of waste biomass into a high-quality internal carbon source that is easy to utilize efficiently for biogas slurry treatment. This allows for the efficient utilization of the abundant carbon source in waste biomass without the need to purchase expensive commercial carbon sources. Furthermore, compared to conventional commercial carbon sources, the internal carbon source can enhance the activity of biogas slurry, promote the denitrification and phosphorus removal effects of microorganisms in biogas slurry, and at the same time improve the carbon source utilization rate and reduce the system process cost. Attached Figure Description

[0064] Figure 1This is a schematic diagram of the biomass treatment device system based on internal carbon source circulation in Example 1; Among them, 1 is a waste biomass pretreatment unit; 21 is a hydrolysis acidification tank; 22 is an anaerobic fermentation tank; 23 is a biogas slurry conditioning and dehydration device; 24 is a biogas slurry temporary storage tank; 31 is a carbon source preparation tank; 32 is a screening device; and 4 is a biogas slurry treatment unit. Figure 2 This is a schematic diagram of the carbon source preparation tank. Detailed Implementation

[0065] This invention provides a biomass treatment device system based on internal carbon source circulation, the biomass treatment device system comprising: Waste biomass pretreatment unit, biogas slurry generation unit, biogas slurry treatment unit, and internal carbon source preparation unit.

[0066] The waste biomass pretreatment unit is used to pretreat waste biomass to form an organic slurry for subsequent processes. The specific steps in the waste biomass pretreatment unit include sorting and pulping.

[0067] One path of the waste biomass pretreatment unit is connected to the biogas slurry generation unit, which then transports the generated organic slurry to the biogas slurry generation unit. The organic slurry formed from the waste biomass is processed by the biogas slurry generation unit to produce biogas, biogas residue, and biogas slurry.

[0068] The biogas slurry generation unit comprises a hydrolysis acidification tank, an anaerobic fermentation tank, and a biogas slurry conditioning and dewatering device connected in sequence. Organic slurry undergoes hydrolysis acidification and anaerobic fermentation processes sequentially in the hydrolysis acidification tank and anaerobic fermentation tank, producing biogas and digestate. The biogas can be purified and utilized in downstream processes such as biogas desulfurization, biogas boilers, and biogas power generation. The digestate enters the biogas slurry conditioning and dewatering device for conditioning and dewatering, forming biogas slurry and biogas residue. The biogas residue is then transported externally.

[0069] Preferably, the process of the biogas slurry conditioning and dewatering device specifically includes conditioning and pressure filtration, including a conditioning tank and a high-pressure diaphragm filter press. In the conditioning tank, conditioning agents such as PAM and iron salts are added to the digestate for conditioning. After conditioning, the biogas slurry is dewatered using a high-pressure diaphragm filter press to obtain biogas slurry and biogas residue. The hydrolysis acidification tank, anaerobic fermentation tank, conditioning tank, and high-pressure diaphragm filter press are conventional equipment in the art, and their structures are not specifically limited.

[0070] Another path of the waste biomass pretreatment unit is connected to the internal carbon source preparation unit. The organic slurry is transported to the internal carbon source preparation unit, where the large molecular organic matter in the waste biomass is degraded into smaller molecules to obtain the finished carbon source.

[0071] The internal carbon source preparation unit includes a carbon source preparation tank and a screening device connected in sequence. In the carbon source preparation tank, functional microorganisms for organic matter degradation are inoculated. Under the action of these microorganisms, the macromolecules in the organic slurry are decomposed into smaller soluble substances, such as glucose and amino acids, and then further decomposed into alcohols or volatile organic acids, such as acetic acid, propionic acid, and butyric acid, becoming a high-quality, easily usable finished carbon source. In the screening device, the decomposed and transformed organic slurry is screened to separate the finished carbon source and residue.

[0072] Preferably, one path of the biogas slurry flowing out of the biogas slurry generating unit is connected to a carbon source preparation tank, and the biogas slurry is transported to the carbon source preparation tank to supplement the alkalinity in the carbon source preparation tank and provide trace amounts of dissolved oxygen.

[0073] Preferably, the screening device is connected to the anaerobic digester of the biogas slurry generation unit through a material residue pipeline, and the generated material residue is transported to the anaerobic digester for fermentation treatment.

[0074] Preferably, the carbon source preparation tank includes a tank body, an agitator arranged axially along the center of the tank body, and heat exchange coils spirally arranged along the inner side of the tank body. A detection device is provided on the side of the tank body for real-time monitoring of the slurry inside the tank. The detection device includes an online COD analyzer, a pH meter, a level gauge, and a thermometer. The screening device employs a multi-stage vibrating screen, with the final stage screen having a mesh size ≥ 70 mesh.

[0075] Another path of the biogas slurry generating unit is connected in parallel with the internal carbon source preparation unit to the biogas slurry treatment unit. The biogas slurry generated by the biogas slurry generating unit is transported to the biogas slurry treatment unit, and the finished carbon source prepared by the internal carbon source preparation unit is added to the biogas slurry to be treated. Then, the biogas slurry undergoes biochemical treatment.

[0076] The specific processes of the biogas slurry treatment unit include nitrification, denitrification, and MBR (membrane bioreactor) treatment. The treated biogas slurry meets discharge standards. The equipment and processes of the biogas slurry treatment unit adopt conventional techniques in the field and are not specifically limited.

[0077] Preferably, the biogas slurry treatment unit is equipped with a separation and sedimentation device, which is connected to the carbon source preparation tank in the internal carbon source preparation unit. The treated biogas slurry is filtered, separated, and settled to separate the sludge components containing functional bacteria, which are then transported to the carbon source preparation tank for reuse. This replenishes the carbon source preparation tank with functional bacteria and activity, eliminating the need for additional external addition of functional bacteria.

[0078] This invention provides a biomass treatment method based on internal carbon source circulation, using the aforementioned biomass treatment device system based on internal carbon source circulation. The biomass treatment method includes the following steps: (1) Pretreatment: Waste biomass, including kitchen waste, biochemical sludge or fecal matter, is pretreated in a waste biomass pretreatment unit to form an organic slurry for subsequent processes. The organic slurry must meet the following requirements: solids content (TS) of 6%-12%, particle size ≤10mm, and oil content ≤5000mg / L.

[0079] (2) Hydrolysis acidification, anaerobic fermentation and conditioning dehydration: The organic slurry is hydrolyzed and acidified in a hydrolysis and acidification tank. During the hydrolysis and acidification process, the pH of the slurry is controlled at 3-4, the temperature is 25-40℃, and the residence time is 2-3 days.

[0080] The hydrolyzed and acidified organic slurry was subjected to anaerobic fermentation in an anaerobic digester. During anaerobic fermentation, the pH of the slurry was controlled at 7.2-8.2, the temperature at 36-39℃, and the slurry was continuously stirred at a stirring intensity ≥3.3 W / m. 3 The total solids content (TS) of the slurry is controlled to be ≤3.0%, the volatile solids content (VS) to be ≤52%, the volatile organic acid content (VFA) to be ≤1000mg / L, and the oil content to be ≤500mg / L. After anaerobic fermentation, biogas and digestate are obtained. The biogas is then processed and utilized in the post-process of biogas purification and utilization.

[0081] The digestate is conditioned and dehydrated in a biogas slurry conditioning and dehydration device, specifically including: first, adding a conditioning agent to the digestate, the conditioning agent including FeCl3 and / or cationic polyacrylamide (PAM), the amount of FeCl3 added is 3%-6% of the total dissolved solids in the digestate dry, the amount of PAM added is 0.3%-0.6% of the total dissolved solids in the digestate dry, FeCl3 is added in the form of a solution with a concentration ≤30%, and PAM is added in the form of a solution with a concentration ≤2%; then, the conditioned digestate is dehydrated by high-pressure diaphragm filtration to obtain biogas residue with a water content ≤65% and biogas slurry with a suspended solids content ≤5000mg / L; the biogas residue is then sent for composting.

[0082] (3) Preparation of internal carbon source: A portion of the organic slurry undergoes carbon source conversion in a carbon source preparation tank, which is then inoculated with functional microbial communities for biomass decomposition. These functional microbial communities include macromolecular decomposition bacteria and small-molecule acidifying bacteria. The macromolecular decomposition bacteria include Bacillus and / or Clostridium. These bacteria secrete extracellular enzymes to decompose large organic molecules in the slurry into small soluble substances, such as glucose and amino acids. The small-molecule acidifying bacteria include at least one of Lactobacillus, Bifidobacterium, or Bacteroides. These bacteria further decompose the already obtained small soluble substances into volatile organic acids, providing a high-quality carbon source. The inoculation method includes inoculating activated sludge with functional microbial communities and / or inoculants containing these functional microbial communities. The activated sludge includes sludge settled in the secondary sedimentation tank of the aerobic process in a municipal wastewater treatment plant. During the carbon source conversion process, slurry parameters are continuously monitored, and the dissolved oxygen concentration is controlled to be <1 mg / L. The biogas slurry generated in the system is continuously added to the slurry to replenish alkalinity, maintaining the slurry pH within the range of 5.0-6.5, and utilizing the biogas slurry to provide trace amounts of dissolved oxygen. Under the influence of the recycled biogas slurry, the pH in the carbon source preparation tank fluctuates, causing macromolecular decomposing bacteria and small-molecule acidifying bacteria to alternately operate within their optimal activity ranges. Through the synergistic metabolic action of these two types of bacteria, the efficiency of organic matter hydrolysis and acidification is maximized. The residence time of the slurry in the tank is controlled to be 3-15 days. The carbon source conversion process is terminated when the ratio of volatile organic acids (VFA) to COD (VFA / COD) is ≥10%, or when the VFA content is ≥10000 mg / L. The slurry that has undergone carbon source conversion is screened with a mesh size of ≥70 mesh. The undersize material is used as the finished carbon source, while the oversize material is sent to the anaerobic digester of the biogas slurry generation unit for anaerobic fermentation or sent out with biogas residue.

[0083] Steps (2) and (3) are not in any particular order.

[0084] (4) Biogas slurry treatment: The obtained carbon source is added to the biogas slurry. After adding the carbon source, the carbon-to-nitrogen ratio (COD / NH3) in the biogas slurry is controlled at (3.8-5.5):1. Then the biogas slurry is subjected to biochemical treatment. The biochemical treatment process includes nitrification, denitrification and MBR treatment. During the biochemical treatment process, ultrafiltration and sedimentation are used to separate the sludge in the biogas slurry. The sludge is returned to the carbon source preparation tank to replenish the functional bacteria and their activity. There is no need to add functional bacteria again during system operation.

[0085] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0086] Example 1 This embodiment provides a method such as Figure 1 The illustrated biomass treatment device system based on internal carbon source circulation includes: Waste biomass pretreatment unit 1, biogas slurry generation unit, biogas slurry treatment unit 4, and internal carbon source preparation unit.

[0087] The biogas slurry generating unit includes a hydrolysis acidification tank 21, an anaerobic fermentation tank 22, a biogas slurry conditioning and dehydration device 23, and a biogas slurry temporary storage tank 24 connected in sequence.

[0088] The internal carbon source preparation unit includes a carbon source preparation tank 31 and a screening device 32 connected in sequence. The screening device is a multi-stage vibrating screen. A schematic diagram of the carbon source preparation tank 31 is shown below. Figure 2 As shown.

[0089] One path of the waste biomass pretreatment unit 1 is connected to the hydrolysis acidification tank 21 of the biogas slurry generation unit, and the other path of the waste biomass pretreatment unit 1 is connected to the carbon source preparation tank 31 of the internal carbon source preparation unit.

[0090] One of the biogas slurry storage tank 24 of the biogas slurry generation unit is connected in parallel to the screening device 32 of the internal carbon source preparation unit and then connected to the biogas slurry treatment unit 4.

[0091] Another path of the biogas slurry storage tank 24 of the biogas slurry generation unit is connected to the carbon source preparation tank 31 for conveying biogas slurry for carbon source preparation.

[0092] This embodiment also provides a biomass treatment method based on internal carbon source circulation. Using the above-mentioned biomass treatment device system based on internal carbon source circulation, the biomass treatment method includes the following steps: (1) Pre-treat waste biomass (kitchen waste, feces) to form organic slurry, control the solid content of the organic slurry to 8%, the solid particle size in the organic slurry ≤ 10 mm, and the oil content ≤ 5000 mg / L; (2) The organic slurry is first hydrolyzed and acidified. During hydrolysis and acidification, the pH of the slurry is controlled at 3-4, the temperature is within the range of 25-40℃, and the residence time is 2 days. Then, anaerobic fermentation is carried out. During anaerobic fermentation, the pH of the slurry is controlled at 7.2-8.2, the temperature is 36-39℃, and continuous stirring is maintained. During the process, the total solids content (TS) of the slurry is always controlled to be ≤3.0%, the volatile solids content (VS) to be ≤52%, and the volatile organic acid content (VFA) to be ≤1000mg. / L, oil content ≤500mg / L, after which biogas and digestate are obtained; add 30% FeCl3 solution and 2% PAM solution to digestate, the amount of FeCl3 added is 5% of the total dry dissolved solids in digestate, the amount of PAM added is 0.5% of the total dry dissolved solids in digestate, and then perform high-pressure diaphragm filtration on the conditioned digestate to obtain biogas residue with water content ≤65% and biogas slurry with suspended solids content ≤5000mg / L; (3) Inoculate the carbon source preparation tank with sludge from the secondary sedimentation tank of the aerobic process of the municipal wastewater treatment plant as activated sludge. Dilute the municipal sludge to a mixed liquid with a solid content of 10%. The inoculation amount is 1 / 2 of the effective volume of the carbon source preparation tank, submerging the bottom layer of the central vertical mixer blades. After inoculation, turn on the mixer and keep it continuously stirred for 24 hours. Through continuous acclimatization and adaptation, ensure that the bacterial community can efficiently adapt to the metabolic needs of the carbon source preparation process. Add the organic slurry to the carbon source preparation tank and continue stirring to carry out carbon source conversion. During the process, continuously monitor the parameters of the organic slurry and control the dissolved oxygen of the slurry. For concentrations <1 mg / L, the biogas slurry produced in the system is continuously added to the slurry to replenish alkalinity, and the pH of the slurry is controlled within the range of 5.0-6.5. The slurry is left in the tank for several days. When the ratio of VFA (volatile organic acid content) to COD (VFA / COD) is ≥10%, or when VFA (volatile organic acid content) is ≥10000 mg / L, the material after carbon source conversion is screened on a multi-stage vibrating screen. The first-stage screen is 70 mesh, and the second-stage screen is 200 mesh. The undersize material is the finished carbon source; the oversize material is sent to an anaerobic digester for fermentation to produce biogas.

[0093] (4) Add the obtained carbon source to the biogas slurry. The amount of carbon source added is such that the carbon-nitrogen ratio (COD / NH3) in the biogas slurry reaches the range of (3.8-5.5):1. The biogas slurry is subjected to biochemical treatment. In the biochemical treatment, the activated sludge in the biogas slurry is ultrafiltered and settled. The activated sludge is added to the carbon source preparation tank to supplement the functional bacteria. There is no need to supplement the functional bacteria during the operation of the system. The biogas slurry is discharged after treatment.

[0094] Taking a real-world organic waste treatment project as an example, the waste biomass from kitchen waste and feces is treated through hydrolysis, acidification, and anaerobic fermentation, with a daily processing capacity of approximately 880 tons and a daily production of approximately 720 tons of biogas slurry. The main pollutant parameters in the biogas slurry include: pH 6-9, COD 1500-3000 mg / L, NH3-N 2000-3500 mg / L, and TS 0.65%-1%. According to the device system and method of this embodiment, the average COD value of the prepared carbon source is approximately 110,000 mg / L. When the carbon source is used for biogas slurry treatment, the system operates stably, and the final effluent indicators consistently meet the ammonia nitrogen limit standard of 50 mg / L (the second time period, level 3 emission standard in DB44 / 26-2001).

[0095] In contrast, if glucose is used to replace the carbon source in the system, approximately 12.90 tons of glucose would be required per day, resulting in a daily carbon source consumption of 25,800 yuan (industrial glucose is priced at 2,000 yuan / ton). The method of this invention can effectively reduce the consumption of purchased carbon sources, greatly improving carbon source utilization and process costs.

[0096] In summary, the device system provided by this invention introduces carbon source preparation into the waste biomass treatment system, realizing the decomposition and transformation of waste biomass into a high-quality internal carbon source that is easy to utilize efficiently for biogas slurry treatment. This allows for the efficient utilization of the abundant carbon source in waste biomass without the need for expensive external purchases of commercial carbon sources. Furthermore, compared to conventional commercial carbon sources, it can enhance the activity of biogas slurry, promote the denitrification and phosphorus removal effects of microorganisms in biogas slurry, and simultaneously improve the carbon source utilization rate and reduce the system's process cost.

[0097] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A biomass treatment device system based on internal carbon source circulation, characterized in that, The biomass processing device system includes: Waste biomass pretreatment unit, biogas slurry generation unit, biogas slurry treatment unit, and internal carbon source preparation unit; One path of the waste biomass pretreatment unit is connected in sequence to the biogas slurry generation unit and the biogas slurry treatment unit, and the other path of the waste biomass pretreatment unit is connected to the biogas slurry treatment unit via the internal carbon source preparation unit.

2. The biomass treatment device system according to claim 1, characterized in that, The internal carbon source preparation unit includes a carbon source preparation tank and a sieving device; Preferably, the carbon source preparation tank includes a tank body, with a stirrer arranged axially along the center of the tank body and a heat exchange coil spirally arranged along the inner side of the tank body; Preferably, a detection device is provided on the side of the tank for real-time detection of the slurry inside the tank; Preferably, the screening device includes a multi-stage vibrating screen; Preferably, the biogas slurry generating unit is connected to the carbon source preparation tank for recycling the biogas slurry to the carbon source preparation tank.

3. The biomass treatment device system according to claim 1 or 2, characterized in that, The biogas slurry generating unit includes a hydrolysis acidification tank, an anaerobic fermentation tank, and a biogas slurry conditioning and dehydration device connected in sequence. Preferably, the biogas slurry conditioning and dewatering device includes a conditioning tank and a high-pressure diaphragm filter press; Preferably, the biogas slurry treatment unit is equipped with an ultrafiltration device, which is connected to an internal carbon source preparation unit for sludge reuse.

4. A biomass treatment method based on internal carbon source recycling, characterized in that, The biomass treatment method uses the biomass treatment device system based on internal carbon source circulation as described in any one of claims 1-3.

5. The biomass treatment method according to claim 4, characterized in that, The biomass treatment method includes the following steps: (1) The waste biomass is pretreated in the waste biomass pretreatment unit to form organic slurry; (2) The organic slurry is processed in the biogas production unit to form biogas, biogas slurry and biogas residue; (3) Take a portion of the organic slurry and inoculate it with functional bacteria for biomass decomposition in the internal carbon source preparation unit to convert it into a carbon source, and finally obtain the finished carbon source. (4) Add the obtained finished carbon source to the obtained biogas slurry to supplement the carbon source, and then perform biochemical treatment on the biogas slurry in the biogas slurry treatment unit; Steps (2) and (3) are not in any particular order.

6. The biomass treatment method according to claim 5, characterized in that, The solids content of the organic slurry in step (1) is 6%-12%; Preferably, the solid particle size in the organic slurry in step (1) is ≤10mm; Preferably, the oil content of the organic slurry in step (1) is ≤5000mg / L.

7. The biomass treatment method according to claim 5 or 6, characterized in that, The treatment in step (2) includes hydrolysis acidification, anaerobic fermentation, conditioning, and dehydration in sequence; Preferably, the pH of the hydrolysis acidification is controlled at 3-4; Preferably, the hydrolysis and acidification temperature is 25-40℃; Preferably, the hydrolysis and acidification time is 2-3 days; Preferably, the pH of the anaerobic fermentation is controlled at 7.2-8.2; Preferably, the temperature for the anaerobic fermentation is 36-39°C; Preferably, during the anaerobic fermentation, stirring is maintained, and the stirring intensity is ≥3.3 W / m. 3 ; Preferably, in the anaerobic fermentation, the total solids content of the slurry is controlled to be ≤3.0%; Preferably, in the anaerobic fermentation, the volatile solids content of the slurry is controlled to be ≤52%; Preferably, in the anaerobic fermentation, the concentration of volatile organic acids in the slurry is controlled to be ≤1000mg / L; Preferably, in the anaerobic fermentation, the oil content of the slurry is controlled to be ≤500mg / L; Preferably, the conditioning agent used in the conditioning includes iron salts and / or cationic polyacrylamide; Preferably, the iron salt includes FeCl3; Preferably, the amount of iron salt used is 3%-6% of the total dry dissolved solids in the digestive fluid to be prepared; Preferably, the amount of cationic polyacrylamide used is 0.3%-0.6% of the total dissolved solids (DDS) in the digestion solution to be prepared. Preferably, the dehydration method is high-pressure diaphragm filtration; Preferably, the moisture content of the biogas residue obtained after dehydration is ≤65%; Preferably, the suspended solids content of the biogas slurry obtained by dehydration is ≤5000mg / L.

8. The biomass treatment method according to any one of claims 5-7, characterized in that, The inoculation method includes inoculating activated sludge with functional microbial communities and / or microbial agents with functional microbial communities. Preferably, the activated sludge comprises sludge settled in the secondary sedimentation tank of the aerobic process in a municipal wastewater treatment plant. Preferably, the method for inoculating the activated sludge includes: diluting the activated sludge to a solid content of more than 10%, and then inoculating it into the carbon source conversion container in the internal carbon source preparation unit to reach more than 1 / 3 of the effective volume of the container; Preferably, the functional microbial community includes macromolecule decomposing functional bacteria and small molecule acidifying functional bacteria; Preferably, the macromolecular decomposing bacteria include Bacillus and / or Clostridium. Preferably, the small molecule acidifying functional bacteria include at least one of Lactobacillus, Bifidobacterium, or Bacteroides.

9. The biomass treatment method according to any one of claims 5-8, characterized in that, In the carbon source conversion, the dissolved oxygen concentration of the organic slurry is controlled to be <1 mg / L; Preferably, in the carbon source conversion, the pH of the organic slurry is controlled to be 5.0-6.5 by adding the biogas slurry produced in step (2); Preferably, in the carbon source conversion, the residence time of the organic slurry is 3-15 days; Preferably, the carbon source conversion process is completed when the VFA / COD ratio in the organic slurry is ≥10%, or the VFA (volatile organic acid content) is ≥10000 mg / L. Preferably, after the carbon source conversion is completed, the resulting slurry is screened; Preferably, the final screening stage has a mesh size of ≥70 mesh.

10. The biomass treatment method according to any one of claims 5-9, characterized in that, In step (4), the finished carbon source is added to the biogas slurry, and the COD / NH3 ratio is (3.8-5.5):

1. Preferably, the biochemical treatment in step (4) includes nitrification, denitrification, and membrane bioreactor treatment; Preferably, in the biochemical treatment of step (4), the biogas slurry is subjected to ultrafiltration treatment to separate activated sludge, which is then reused for the carbon source conversion.

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