A method and device for producing gas by anaerobic fermentation of sludge and kitchen waste

Abstract

The invention relates to a method and device for producing gas by anaerobic fermentation of sludge and kitchen waste in coordination, comprising the following steps: S1, hydrothermally pretreating excess sludge from a sewage treatment plant to obtain WAS; S2, sorting 50L of kitchen waste to remove impurities and draining and screening, taking the sieve-surface material and putting it into a grinder for crushing, mixing the sieve-surface material with the sieve-surface material liquid as test kitchen waste (FW), and storing the mixture in a refrigerator at 4°C; S3, taking 5L of inoculated sludge and placing it in a fermentation tank at 37°C for acclimatization for 20 to 30 days, standing it for about 14 days after stabilization, and inoculating it after the sludge completely stops producing gas; and S4, regulating the organic load rate, feeding method, fermentation temperature and stirring intensity of FW and WAS according to the demand for acid and gas production. The invention has the advantages of increasing the yield of VFAs and biogas produced by coordinated anaerobic fermentation according to the demand.

Description

Technical Field

[0001] The invention belongs to the technical field of garbage treatment methods, and specifically relates to a method and device for producing gas through coordinated anaerobic fermentation of sludge and kitchen waste. Background Art

[0002] With the development of my country's economy, investment in the sewage treatment industry has gradually increased, and the number of sewage treatment plants has increased, leading to an increase in sludge production. At the same time, with the improvement of people's living standards, the use of nitrogen and phosphorus elements has increased, resulting in the C / N ratio of discharged sewage not meeting the standard, which increases the difficulty of subsequent sewage treatment.

[0003] The anaerobic digestion of pure food waste projects causes a high carbon-nitrogen ratio due to excessive carbohydrate and fat content, resulting in acid production that is higher than the consumption of methanogenesis. Excessive acid accumulation is prone to produce volatile acid inhibition such as propionic acid, while low carbon-nitrogen ratios, i.e. high protein content, are prone to ammonia nitrogen inhibition. Actual production also faces problems such as system energy recovery, supporting sewage treatment, and biogas residue resource utilization;

[0004] The coordinated anaerobic fermentation of sludge and food waste can make the substrate nutritionally balanced and more suitable for the growth of microorganisms, solve the problems existing in separate fermentation, thereby improving the efficiency of acid and gas production, and solving the problem of resource disposal of food waste and residual sludge. However, due to the influence of pretreatment methods and reaction conditions, the production of volatile fatty acids (VFAs) and biogas is relatively low. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method and device for producing gas by anaerobic fermentation of sludge and kitchen waste, which can increase the VFAs and biogas produced by anaerobic fermentation according to demand.

[0006] The technical solution of the present invention is as follows:

[0007] A method for producing gas by anaerobic fermentation of sludge and kitchen waste, comprising the following steps:

[0008] S1. Hydrothermally pretreating the excess sludge from the sewage treatment plant to obtain activated sludge waste WAS;

[0009] S2, sorting out 50L of food waste to remove impurities and draining and sieving, taking the sieve material and putting it into a grinder for crushing, and mixing the sieve material liquid with the sieve material liquid after crushing as the test food waste FW, and storing it in a refrigerator at 4°C;

[0010] S3, take 5L of inoculated sludge and place it in a fermentation tank at 37℃ for acclimatization for 20-30 days. After stabilization, let it stand for about 14 days, and then inoculate it after the sludge completely stops producing gas;

[0011] S4. When acid production is required, WAS and FW are adjusted to 88% moisture content, the feed organic load rate of WAS and FW is set to 3gCOD·L-1day-1, the mixed material is added to the fermenter at a rate of 10L per day and once per day, and the anaerobic fermentation temperature is set to 45-55℃ and the stirring intensity is set to 120r / min for continuous fermentation, and each variable cycle is 3 weeks;

[0012] S5. When gas production is required, adjust the moisture content of WAS and FW to 92%, set the feed organic load rate of WAS and FW to 3gCOD·L-1day-1, add the mixed material to the fermenter at a rate of 10L per day and twice a day, and set the anaerobic fermentation temperature to 35-40℃ and the stirring intensity to 120r / min for continuous fermentation. Each variable cycle is 3 weeks.

[0013] Further, the total solids of the activated sludge waste range from 18.54 to 19.22 g / L, the volatile solids range from 12.28 to 12.46 g / L, the soluble chemical oxygen demand range from 85.9 to 107.1 mg / L, the protein relative to the volatile solids range from 27.5 to 31.5 mg / L, the polysoluble polysaccharides range from 4.3 to 7.9 mg / L, and the ammonia nitrogen content range from 5.05 to 6.85 mg / L;

[0014] The total solids of the test kitchen waste ranged from 10.12 to 10.32 g / L, the volatile solids ranged from 9.62 to 9.84 g / L, the soluble chemical oxygen demand ranged from 5339.1 to 5604.1 mg / L, the protein relative to the volatile solids ranged from 167.8 to 199.8 mg / L, the polysoluble polysaccharides ranged from 2548 to 2678.8 mg / L, and the ammonia nitrogen content ranged from 725.8 to 841 mg / L;

[0015] The total solids of the inoculated sludge range from 25.62 to 25.86 g / L, the volatile solids range from 21.21 to 21.41 g / L, the soluble chemical oxygen demand range from 1086.7 to 1190.7 mg / L, the protein relative to volatile solids range from 20.7 to 25.9 mg / L, the polysoluble polysaccharides range from 725.8 to 841 mg / L, and the ammonia nitrogen content ranges from 12.7 to 17.9 mg / L.

[0016] Furthermore, the hydrothermal pretreatment of excess sludge from a sewage treatment plant comprises:

[0017] S11, take 200L of sludge and place it in a collection tank, adjust the solid content of the sludge to 5%-25%, and transport the sludge to the reactor for stirring and preheating. The preheated sludge is about 100°C;

[0018] S12, open the valve of the reactor to control the steam flow and adjust the pressure to 0.6 MPa, adjust the temperature to 120-200°C, react for 15-45 minutes, flash evaporate and cool to room temperature, then place in a storage tank, and store in a refrigerator at 4°C to obtain WAS.

[0019] The present invention also provides a sludge and kitchen waste coordinated anaerobic fermentation gas production device for the above-mentioned sludge and kitchen waste coordinated anaerobic fermentation gas production method, comprising a tank body, a heating shell sealed and fixed to the outer side of the tank body, and a stirring assembly arranged on the tank body, the two ends of the upper side of the tank body are respectively fixedly connected with a detection port and a feed port, and the bottom of the tank body is fixed with a discharge port passing through the heating shell.

[0020] Furthermore, a step ring is provided at the upper end of the heating shell and is sealed and fixed with the outer wall of the tank body. The upper and lower sides of the interior of the heating shell are respectively connected with an upper ring and a lower ring in a rotational sealing manner. The upper ring and the lower ring are both rotationally sealed with the outer side surface of the tank body. A water storage space is formed between the upper ring and the step ring. The upper ring is sealed and fixed with a plurality of fan plates that are in contact and sealed with the step ring, the outer wall of the tank body and the inner wall of the heating shell. The plurality of fan plates are arranged in a ring shape with the center of the upper ring as the center, so as to divide the water storage space into a plurality of driving and drainage spaces.

[0021] The lower ring divides the area of ​​the heating shell below the upper ring into a first heating zone and a second heating zone. The first heating zone is provided with a drainage heating component connected to each driven drainage space. The drainage heating component rotates with the rotation of the upper ring to heat the tank body. The heating shell is fixed with a first heating port connected to the water storage space to drive the fan plate to rotate. The water in the drainage heating component is discharged from the second heating zone.

[0022] Furthermore, a connecting component is provided in the driving drainage space, and the connecting component includes a socket fixed in the driving drainage space, a hole barrel elastically sealed and plugged in the socket, and a ball fixed at the upper end of the hole barrel. An arc-shaped depression is provided on the lower side of the step ring, and the arc-shaped depression is located on one side of the first heating port and the angle between the two is greater than 45°, so that the water in the first heating port can drive the fan plate normally;

[0023] When the ball is located in the arc-shaped depression, the hole barrel is connected to the driving drainage space, and the lower end of the socket is connected to the drainage heating component.

[0024] Furthermore, a reset groove is provided on the inner wall of the socket, a reset ring is provided in the reset groove to slide up and down, and a reset spring fixed in the reset groove is provided on the lower side of the reset ring.

[0025] Furthermore, the drainage heating assembly is independently connected to a connecting pipe connected to the socket, a spiral heating tube spirally arranged on the outer side of the tank body, and a drainage pipe connected to the upper end of the spiral heating tube, the lower ring is hollow inside and the connecting pipe is connected to the spiral heating tube via the lower ring, the lower end of the drainage pipe is sealed and passes through the lower ring and extends into the second heating zone, and the spiral heating tube is fixed to the upper ring and the lower ring.

[0026] Furthermore, the second heating zone is fixedly connected with a drain port and a second heating port, and the water injection pressure of the first heating port is greater than the water injection pressure of the second heating port.

[0027] Furthermore, the stirring assembly includes a motor fixed on the top of the tank body and a stirring rod rotatably connected to the inside of the tank body, wherein the stirring rod is connected to the motor.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention optimizes the parameters of the anaerobic fermentation of excess sludge and kitchen waste, and can utilize the anaerobic fermentation liquid of excess sludge and kitchen waste as a carbon source for low carbon-nitrogen ratio sewage treatment according to the requirements of different engineering scenarios, thereby achieving efficient nitrogen and phosphorus removal. At the same time, the biogas generated by anaerobic fermentation can be used to generate electricity to supply the anaerobic fermentation system, thereby achieving system self-sufficiency and reducing operating costs.

[0030] 2. The present invention provides a drainage heating component to stabilize the temperature between the residual sludge and the kitchen waste in the tank, thereby ensuring gas and acid production.

[0031] In summary, the present invention has the advantages of increasing the yield of VFAs and biogas produced by synergistic anaerobic fermentation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the device of the present invention;

[0033] Figure 2 For the present invention Figure 1 A schematic diagram of the structure of the heating shell;

[0034] Figure 3 For the present invention Figure 1 A schematic diagram of the front view structure after removing the heating shell;

[0035] Figure 4 For the present invention Figure 1 A schematic diagram of the enlarged structure of part A;

[0036] Figure 5 For the present invention Figure 1 A schematic diagram of the enlarged structure of part B;

[0037] Figure 6 For the present invention Figure 1Schematic diagram of the position of the arc-shaped depression;

[0038] Figure 7 For the present invention Figure 1 Schematic diagram of the structure of connected components.

[0039] In the figure, 1. motor, 2. detection port, 3. first heating port, 4. heating shell, 41. step ring, 42. arc-shaped depression, 43. fan plate, 44. drain pipe, 45. lower ring, 46. connecting component, 461. ball, 462. hole barrel, 463. reset ring, 464. reset spring, 465. reset groove, 466. socket, 48. connecting pipe, 49. upper ring, 5. stirring rod, 6. tank body, 8. second heating port, 9. discharge port, 10. drain port, 11. spiral heating tube, 12. feed port, 13. first heating zone, 14. second heating zone. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] A method for producing gas by anaerobic fermentation of sludge and kitchen waste, comprising the following steps:

[0043] S1. Hydrothermally pretreating the excess sludge from the sewage treatment plant to obtain activated sludge waste WAS;

[0044] S11, take 200L of sludge and place it in a collection tank, adjust the solid content of the sludge to 5%-25%, and transport the sludge to the reactor for stirring and preheating. The preheated sludge is about 100°C;

[0045] S12, open the valve of the reactor to control the steam flow and adjust the pressure to 0.6 MPa, adjust the temperature to 120-200°C, react for 15-45 minutes, flash evaporate and cool to room temperature, then place in a storage tank, and store in a refrigerator at 4°C to obtain WAS;

[0046] S2, sort out 50L of food waste to remove impurities and drain and sieve, take the sieve material and put it into a grinder for crushing, mix the sieve material with the sieve material liquid after crushing as the test food waste (FW), and store it in a refrigerator at 4°C;

[0047] S3, take 5L of inoculated sludge and place it in a fermentation tank at 37℃ for acclimatization for 20-30 days. After stabilization, let it stand for about 14 days, and then inoculate it after the sludge completely stops producing gas;

[0048] S4, WAS and FW were adjusted to the same moisture content (88%, 90%, 92%, 94%, 96%), and three groups of feed organic load rates with different mixture ratios (WAS and FW) were set, which were 1gCOD·L -1 d -1 , 2gCOD·L -1 d -1 and 3gCOD·L -1 d -1 The mixed material was added to the fermenter reactor at a rate of 10 L per day, once or twice per day, and different anaerobic fermentation temperatures (25, 35, 40, 45, 55 °C) and stirring intensities (120 r / min, 150 r / min, 180 r / min) were set for continuous fermentation, with each variable cycle lasting 3 weeks.

[0049] The gas production readings are taken before feeding every day, and data analysis is performed. The anaerobic sampling position is at the bottom and side wall of each anaerobic tank. Sampling is performed before feeding, and VFAs, alkalinity, COD, total solids, volatile solids, etc. are tested. In case of abnormal conditions, sampling and testing are performed at any time;

[0050] Among them, the total solids of the activated sludge waste range from 18.54 to 19.22 g / L, the volatile solids range from 12.28 to 12.46 g / L, the soluble chemical oxygen demand range from 85.9 to 107.1 mg / L, the protein relative to the volatile solids range from 27.5 to 31.5 mg / L, the polysoluble polysaccharide range from 4.3 to 7.9 mg / L, and the ammonia nitrogen content range from 5.05 to 6.85 mg / L;

[0051] The total solids of the test kitchen waste ranged from 10.12 to 10.32 g / L, the volatile solids ranged from 9.62 to 9.84 g / L, the soluble chemical oxygen demand ranged from 5339.1 to 5604.1 mg / L, the protein relative to the volatile solids ranged from 167.8 to 199.8 mg / L, the polysoluble polysaccharides ranged from 2548 to 2678.8 mg / L, and the ammonia nitrogen content ranged from 725.8 to 841 mg / L;

[0052] The total solids of the inoculated sludge range from 25.62 to 25.86 g / L, the volatile solids range from 21.21 to 21.41 g / L, the soluble chemical oxygen demand range from 1086.7 to 1190.7 mg / L, the protein relative to the volatile solids range from 20.7 to 25.9 mg / L, the polysoluble polysaccharides range from 725.8 to 841 mg / L, and the ammonia nitrogen content ranges from 12.7 to 17.9 mg / L;

[0053] 1) Evaluation indicators

[0054] During the anaerobic digestion of sludge, a variety of substances are produced, such as soluble COD (soluble chemical oxygen demand), volatile fatty acids (VFAs), ammonia nitrogen (NH4+-N), total nitrogen (TN), phosphate (PO43--P), total phosphorus (TP), soluble polysaccharides, etc.

[0055] Anaerobic fermentation of sludge will decompose some of the original large-molecule, insoluble organic matter in the sludge through microorganisms in an anaerobic environment, producing small-molecule soluble organic matter such as glucose, amino acids and short-chain fats (i.e., soluble chemical oxygen demand). These substances can provide a matrix for subsequent anaerobic reactions, so soluble chemical oxygen demand is used as one of the sludge fermentation test indicators.

[0056] While the sludge is undergoing hydrolysis, the acidification reaction is also taking place at the same time. This stage mainly converts the glucose and short-chain fats produced in the hydrolysis stage into short-chain fatty acids (VFAs) such as acetic acid, propionic acid, and butyric acid. During the growth of microorganisms, these short-chain fatty acids can provide a high-quality carbon source. In the sewage treatment process, there is a problem of insufficient carbon source, which can provide a carbon source for biological denitrification. Therefore, VFAs is used as one of the sludge hydrolysis test indicators.

[0057] During the anaerobic digestion process, sludge will produce a large amount of ammonia nitrogen. This ammonia nitrogen is mainly due to the pretreatment of the sludge, which causes some of the original microbial cells in the sludge to rupture, and a large amount of organic nitrogen in the cells flows out and is converted into ammonia nitrogen through hydrolysis. In addition, in the anaerobic environment, the cell proliferation rate slows down, and only part of the ammonia nitrogen is converted into cytoplasm, which increases the ammonia nitrogen content in the anaerobic digestion liquid. Total nitrogen is the total content of nitrogen in the anaerobic digestion liquid. In the anaerobic reaction, total nitrogen accounts for most of the ammonia nitrogen, so the ammonia nitrogen content and changes are roughly the same as total nitrogen. The N element is one of the main elements that need to be removed in the sewage treatment process. When it is added as a carbon source, the N content in the sewage will increase, so ammonia nitrogen is used as one of the sludge hydrolysis test indicators.

[0058] Phosphorus is an essential element for biological growth and reproduction. It participates in the metabolism and activities of organisms in various ways. For example, phosphorus is contained in the genetic material of organisms. In sludge anaerobic digestion liquid, phosphorus mainly exists in the form of phosphate. In sludge, phosphorus exists in the cells in the form of polyphosphate. After sludge pretreatment and anaerobic environment, the polyphosphate flowing out of the cytoplasm is hydrolyzed by polyphosphate bacteria and released in the form of phosphate, which increases the total phosphorus in the anaerobic digestion liquid. Since phosphate occupies most of the total phosphorus and the content of the two is close, the P element is one of the main elements that need to be removed in the sewage treatment process. When added as a carbon source, the P element content in the sewage will increase. Therefore, total phosphorus is used as one of the test indicators.

[0059] During the anaerobic digestion of sludge, the higher the soluble chemical oxygen demand, the more VFAs can be produced for anaerobic digestion, which is more conducive to its supplementation in the operation of the sewage treatment plant. However, during anaerobic digestion, the N and P content of the carbon source itself will also increase, which will increase the sewage treatment load of the sewage treatment plant. Therefore, carbon sources with a higher C / N ratio are more suitable for addition to the operation of the sewage treatment plant.

[0060] 2) Analysis methods

[0061] Dissolved COD, VFAs, TP, NH4 + -N and other substances were first filtered through 0.45um filter paper before being measured, and the measurement method was carried out in accordance with the standard analysis method prescribed by the state.

[0062] VFAs mainly include six types, namely: acetic acid (5.6±0.2s), propionic acid (6.2±0.2s), isobutyric acid (6.4±0.2s), n-butyric acid (6.9±0.2s), isovaleric acid (7.2±0.2s), and n-valeric acid (7.7±0.2s). The peak time will fluctuate slightly with the change of environmental and instrument conditions, and can be analyzed accordingly according to the fixed peak order. Quantitative analysis is mainly based on the standard curve (R2>0.999) between the concentration of the prepared standard solution and the peak area. The conversion coefficients of acetic acid, propionic acid, butyric acid and valeric acid to COD are converted to the concentration under COD equivalent, and the conversion coefficients are 1.067, 1.514, 1.818 and 2.039 respectively;

[0063] Based on the above analysis, the optimal operating conditions of CH4 and VFAs in this embodiment are shown in the following table:

[0064]

[0065] Example 2

[0066] like Figure 1-7As shown, the anaerobic fermentation gas production device for sludge and kitchen waste comprises a tank body 6, a heating shell 4 sealed and fixed to the outer side of the tank body 6, and a stirring assembly arranged on the tank body 6. The two ends of the upper side of the tank body 6 are respectively fixedly connected with a detection port 2 and a feed port 12, and the bottom of the tank body 6 is fixed with a discharge port 9 passing through the heating shell 4;

[0067] When in use, the remaining sludge, food waste and inoculated sludge enter from the feed port 12 and are discharged from the discharge port 9. After the remaining sludge and food waste are placed in the tank body 6 according to the proportions in the above steps, the stirring device stirs them and the heating shell 4 is used to heat them.

[0068] In this embodiment, a step ring 41 is provided at the upper end of the heating shell 4 and is sealed and fixed with the outer wall of the tank body 6. An upper ring 49 and a lower ring 45 are respectively rotatably and sealably connected to the upper and lower sides of the interior of the heating shell 4. Both the upper ring 49 and the lower ring 45 are rotatably and sealably connected to the outer side of the tank body 6. A water storage space is formed between the upper ring 49 and the step ring 41. The upper ring 49 is sealed and fixed with a plurality of fan plates 43 that are in contact and sealed with the step ring 41, the outer wall of the tank body 6 and the inner wall of the heating shell 4. The plurality of fan plates 43 are arranged in a ring shape with the center of the upper ring 49 as the center, so as to divide the water storage space into a plurality of driving and drainage spaces.

[0069] The lower ring 45 divides the area of ​​the heating shell 4 located below the upper ring 49 into a first heating area 13 and a second heating area 14. The first heating area 13 is provided with a drainage heating component connected to each driving drainage space. The drainage heating component rotates with the rotation of the upper ring 49 to heat the tank body 6. The heating shell 4 is fixed with a first heating port 3 connected to the water storage space to drive the fan plate 43 to rotate, and the water in the drainage heating component is discharged from the second heating area 14.

[0070] When in use, the first heating port 3 is connected to an external hot water supply device, so that hot water enters the driving drainage space from the first heating port 3 and drives the fan plate 43 to rotate. The fan plate 43 drives the upper ring 49 and the drainage heating component to rotate. During the rotation of the fan plate 43, hot water enters the driving drainage space, and during the rotation of the upper ring 49, the hot water in the drainage space is driven to enter the drainage heating component. The hot water in the drainage heating component heats the tank body 6 and then gradually cools down and is discharged from the second heating area 14.

[0071] The connecting hole connecting the first heating port 3 and the water storage space is inclined to drive the fan plate 43 to rotate;

[0072] Among them, the water pressure in the water storage space is greater than the water pressure in the second heating zone 14, so that the water in the water storage space can enter the second heating zone 14 through the drainage heating component. For the regulation of water pressure, an overflow valve or a spring one-way valve can be set at the drain outlet 10 of the second heating zone 14, so that when the drainage heating component is connected, the water flow in the second heating zone 14 can be discharged from the drain outlet 10.

[0073] In this embodiment, a connecting component 46 is provided in the driving drainage space, and the connecting component 46 includes a socket 466 fixed in the driving drainage space, a hole barrel 462 elastically sealed and plugged in the socket 466, and a ball 461 fixed at the upper end of the hole barrel 462. An arc-shaped recess 42 is provided on the lower side of the step ring 41, and the arc-shaped recess 42 is located on one side of the first heating port 3 and the angle between the two is greater than 45°, so that the water in the first heating port 3 can normally drive the fan plate 43;

[0074] When the ball 461 is located in the arc-shaped depression 42, the hole barrel 462 is connected to the driving drainage space, and the lower end of the socket 466 is connected to the drainage heating component;

[0075] The elastic connection between the hole barrel 462 and the socket 466 is as follows: a reset groove 465 is provided on the inner wall of the socket 466, a reset ring 463 is slid up and down in the reset groove 465, and a reset spring 464 fixed in the reset groove 465 is provided on the lower side of the reset ring 463;

[0076] When in use, as the upper ring 49 rotates, the connecting component 46 also moves. During the displacement, the ball 461 enters the arc-shaped recess 42. Under the action of the return spring 464, the ball 461 gradually moves along the arc-shaped recess 42, so that the hole barrel 462 gradually moves up to the hole on the hole barrel 462 and extends out of the socket 466. At this time, water can flow into the drainage heating component from the hole on the hole barrel 462. After moving out of the arc-shaped recess 42, the hole barrel 462 is reset and closed.

[0077] The side wall of the arc-shaped recess 42 is arc-shaped, so that the ball 461 can move in or out normally.

[0078] In this embodiment, the drainage heating assembly includes a connecting pipe 48 separately connected to the socket 466, a spiral heating tube 11 spirally arranged on the outer side of the tank body 6, and a drainage pipe 44 connected to the upper end of the spiral heating tube 11. The lower ring 45 is hollow inside and the connecting pipe 48 is connected to the spiral heating tube 11 through the lower ring 45. The lower end of the drainage pipe 44 is sealed and passes through the lower ring 45 and extends into the second heating zone 14. The spiral heating tube 11 is fixed to the upper ring 49 and the lower ring 45. The spiral heating tube 11 has no contact with the tank body 6 and the heating shell 4, and a liquid heat-conducting medium is provided in the first heating zone 13 to ensure uniform heating.

[0079] When in use, as the upper ring 49 rotates, the upper ring 49 rotates and drives the spiral heating tube 11 to rotate. During the rotation process, the hot water in the drainage space is driven into the connecting tube 48 through the connecting component 46. The water in the connecting tube 48 passes through the lower ring 45, the spiral heating tube 11 and the drainage pipe 44 into the second heating area 14. During the flow of water, the heat passes through the liquid heat transfer medium to heat the tank body 6, thereby ensuring uniform heating and heating speed.

[0080] In this embodiment, the second heating zone 14 is fixedly connected to the drain port 10 and the second heating port 8 , and the water injection pressure of the first heating port 3 is greater than the water injection pressure of the second heating port 8 , thereby preventing the hot water from being unable to self-drive the drainage space into the second heating zone 14 .

[0081] In this embodiment, the stirring assembly includes a motor 1 fixed on the top of the tank body 6 and a stirring rod 5 rotatably connected to the inside of the tank body 6 , and the stirring rod 5 is connected to the motor 1 .

[0082] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for producing gas by anaerobic fermentation of sludge and kitchen waste, characterized in that: The steps include: S1. Hydrothermally pretreating the excess sludge from the sewage treatment plant to obtain activated sludge waste WAS; S2, sorting out 50L of food waste to remove impurities and draining and sieving, taking the sieve material and putting it into a grinder for crushing, and mixing the sieve material liquid with the sieve material liquid after crushing as the test food waste FW, and storing it in a refrigerator at 4°C; S3, take 5L of inoculated sludge and place it in a fermentation tank at 37℃ for acclimatization for 20-30 days. After stabilization, let it stand for about 14 days, and then inoculate it after the sludge completely stops producing gas; S4. When acid production is required, WAS and FW are adjusted to 88% moisture content, the feed organic load rate of WAS and FW is set to 3gCOD·L-1day-1, the mixed material is added to the fermenter at a rate of 10L per day and once per day, and the anaerobic fermentation temperature is set to 45-55℃ and the stirring intensity is set to 120r / min for continuous fermentation, and each variable cycle is 3 weeks; S5. When gas production is required, adjust the moisture content of WAS and FW to 92%, set the feed organic load rate of WAS and FW to 3gCOD·L-1day-1, add the mixed material to the fermenter at a rate of 10L per day and twice a day, and set the anaerobic fermentation temperature to 35-40℃ and the stirring intensity to 120r / min for continuous fermentation. Each variable cycle is 3 weeks.

2. The method for producing gas by anaerobic fermentation of sludge and kitchen waste according to claim 1, characterized in that: The total solids of the activated sludge waste range from 18.54 to 19.22 g / L, the volatile solids range from 12.28 to 12.46 g / L, the soluble chemical oxygen demand range from 85.9 to 107.1 mg / L, the protein relative to the volatile solids range from 27.5 to 31.5 mg / L, the polysoluble polysaccharides range from 4.3 to 7.9 mg / L, and the ammonia nitrogen content range from 5.05 to 6.85 mg / L; The total solids of the test kitchen waste ranged from 10.12 to 10.32 g / L, the volatile solids ranged from 9.62 to 9.84 g / L, the soluble chemical oxygen demand ranged from 5339.1 to 5604.1 mg / L, the protein relative to the volatile solids ranged from 167.8 to 199.8 mg / L, the polysoluble polysaccharides ranged from 2548 to 2678.8 mg / L, and the ammonia nitrogen content ranged from 725.8 to 841 mg / L; The total solids of the inoculated sludge range from 25.62 to 25.86 g / L, the volatile solids range from 21.21 to 21.41 g / L, the soluble chemical oxygen demand range from 1086.7 to 1190.7 mg / L, the protein relative to volatile solids range from 20.7 to 25.9 mg / L, the polysoluble polysaccharides range from 725.8 to 841 mg / L, and the ammonia nitrogen content ranges from 12.7 to 17.9 mg / L.

3. The method for producing gas by anaerobic fermentation of sludge and kitchen waste according to claim 1, characterized in that: The hydrothermal pretreatment of excess sludge from a sewage plant comprises: S11, take 200L of sludge and place it in a collection tank, adjust the solid content of the sludge to 5%-25%, and transport the sludge to the reactor for stirring and preheating. The preheated sludge is about 100°C; S12, open the valve of the reactor to control the steam flow and adjust the pressure to 0.6 MPa, adjust the temperature to 120-200°C, react for 15-45 minutes, flash evaporate and cool to room temperature, then place in a storage tank, and store in a refrigerator at 4°C to obtain WAS.

4. A sludge and kitchen waste collaborative anaerobic fermentation gas production device, used in the sludge and kitchen waste collaborative anaerobic fermentation gas production method according to any one of claims 1 to 3, characterized in that: It includes a tank body, a heating shell sealed and fixed on the outer side of the tank body, and a stirring component arranged on the tank body. The two ends of the upper side of the tank body are respectively fixedly connected with a detection port and a feed port, and the bottom of the tank body is fixed with a discharge port passing through the heating shell.

5. The anaerobic fermentation gas production device for sludge and kitchen waste according to claim 4, characterized in that: The upper end of the heating shell is provided with a step ring sealed and fixed with the outer wall of the tank body, the upper and lower sides of the heating shell are respectively connected with an upper ring and a lower ring in a rotational sealing manner, the upper ring and the lower ring are both rotationally sealed with the outer side surface of the tank body, a water storage space is formed between the upper ring and the step ring, the upper ring is sealed and fixed with a plurality of fan plates in contact and sealing with the step ring, the outer wall of the tank body and the inner wall of the heating shell, the plurality of fan plates are arranged in a ring shape with the center of the upper ring as the center, so as to divide the water storage space into a plurality of driving drainage spaces; The lower ring divides the area of ​​the heating shell below the upper ring into a first heating zone and a second heating zone. The first heating zone is provided with a drainage heating component connected to each driven drainage space. The drainage heating component rotates with the rotation of the upper ring to heat the tank body. The heating shell is fixed with a first heating port connected to the water storage space to drive the fan plate to rotate. The water in the drainage heating component is discharged from the second heating zone.

6. The device for producing gas by anaerobic fermentation of sludge and kitchen waste according to claim 5, characterized in that: A connecting component is arranged in the driving drainage space, and the connecting component comprises a socket fixed in the driving drainage space, a hole barrel elastically sealed and plugged in the socket, and a ball fixed at the upper end of the hole barrel. An arc-shaped depression is provided on the lower side of the step ring, and the arc-shaped depression is located on one side of the first heating port, and the angle between the two is greater than 45 degrees, so that the water in the first heating port can drive the fan plate normally; When the ball is located in the arc-shaped depression, the hole barrel is connected to the driving drainage space, and the lower end of the socket is connected to the drainage heating component.

7. The device for producing gas by anaerobic fermentation of sludge and kitchen waste according to claim 6, characterized in that: A reset groove is provided on the inner wall of the socket, a reset ring is slidably arranged in the reset groove, and a reset spring fixed in the reset groove is arranged at the lower side of the reset ring.

8. The device for producing gas by anaerobic fermentation of sludge and kitchen waste according to claim 7, characterized in that: The drainage heating assembly is independently connected to the connecting pipe of the socket, the spiral heating pipe is spirally arranged on the outer side of the tank body, and the drainage pipe is connected to the upper end of the spiral heating pipe. The lower ring is hollow inside and the connecting pipe is connected to the spiral heating pipe through the lower ring. The lower end of the drainage pipe is sealed and passes through the lower ring and extends into the second heating zone. The spiral heating pipe is fixed to the upper ring and the lower ring.

9. The device for producing gas by anaerobic fermentation of sludge and kitchen waste according to claim 8, characterized in that: The second heating zone is fixedly connected with a drain port and a second heating port, and the water injection pressure of the first heating port is greater than the water injection pressure of the second heating port.

10. The device for producing gas by anaerobic fermentation of sludge and kitchen waste according to claim 8, characterized in that: The stirring assembly comprises a motor fixed on the top of the tank body and a stirring rod rotatably connected to the inside of the tank body, wherein the stirring rod is connected to the motor.

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