A coordinated treatment system for urban organic solid waste

Abstract

The invention discloses a coordinated treatment system for urban organic solid waste, which comprises a kitchen waste storage unit, a sludge storage unit, a kitchen waste sorting unit connected to the kitchen waste storage unit, an anaerobic treatment unit connected to the kitchen waste sorting unit, a biogas treatment unit connected to the anaerobic treatment unit, a biogas residue treatment unit connected to the anaerobic treatment unit, a drying unit connected to the sludge storage unit, a separation unit connected to the drying unit, a collection unit connected to the separation unit, an exhaust gas treatment unit and a solid residue treatment unit connected to the collection unit, etc., so as to achieve coordinated treatment of kitchen waste and sludge, with a reduction of more than 90%, an organic matter degradation rate of more than 95%, and ash residue can also be used for making bricks, cement raw materials and other mature building materials, thereby achieving closed-loop treatment of kitchen waste and sludge.

Description

Technical Field

[0001] The present invention relates to the technical field of garbage disposal, and in particular to a system for coordinating the disposal of urban organic solid waste. Background Art

[0002] With the rapid growth of urbanization in my country, the pollution of organic solid wastes such as sludge from urban sewage plants and kitchen waste has become increasingly prominent. Sewage plant sludge has a high water content, is rich in organic matter, is easily corrupted and produces a strong odor, and contains a large number of pathogens, parasite eggs, heavy metals such as chromium and mercury, and toxic, harmful and carcinogenic substances that are difficult to degrade, such as dioxins. If the sludge is simply treated or randomly piled up without treatment, it is easy to cause secondary pollution to groundwater and soil through rainwater erosion and leakage, which directly endangers human health. Kitchen waste has complex sources, poor appearance, high water content, and is easy to corrupt and deteriorate. The serious risk of virus contamination threatens the public health safety of cities. Disorderly and simple treatment can easily lead to problems such as pig swill and gutter oil, which threaten food safety.

[0003] Both sludge and kitchen waste have the characteristics of high water content and rich organic matter. However, as the extracellular polymer residue after biochemical treatment in sewage treatment plants, sludge is difficult to degrade and has a low carbon-nitrogen ratio. The easily degradable organic matter in kitchen waste is 75-90%, the carbon-nitrogen ratio is high, and the quality and composition of organic matter vary greatly. At present, the coordinated disposal of sludge and kitchen waste adopts coordinated anaerobic digestion based on the complementarity of carbon-nitrogen ratio. Although it can improve the gas production rate of anaerobic digestion, the degradation rate of organic matter is low and the reduction is low. The land use of biogas residue after anaerobic digestion has the risk of heavy metal pollution and the industrial chain is difficult to open up, and the final disposal cannot be achieved. Chinese invention patent CN201910429656 discloses a combined treatment process of anaerobic digestion of kitchen waste and high-dryness carbonization of sludge, but the decomposition rate of organic matter in carbonized sludge is low and the gas production is low. The high energy consumption of the system leads to high operating costs. The carbonization byproduct tar is very easy to cause coking and blockage. There is no mature and reliable market for biochar, and large-scale engineering applications cannot be achieved.

[0004] Therefore, combining the pyrolysis and gasification of organic solid wastes such as sludge and sludge with the anaerobic digestion of food waste, and treating sludge and food waste according to their quality and grade can achieve a strong coupling effect, and centralized treatment of urban sludge, food waste and other organic solid wastes can not only save construction and management costs, but also completely solve the problem of the final outlet, which is of great significance to the ecological management and resource utilization of organic solid waste. Summary of the invention

[0005] The purpose of the present invention is to provide a system for the coordinated treatment of urban organic solid waste, which solves the problems of low reduction, incomplete degradation, and difficult final disposal of sludge and kitchen waste caused by simple coordinated treatment, and achieves highly coordinated quality and classification.

[0006] In order to achieve the purpose of the invention, the technical solution adopted by the present invention is specifically as follows:

[0007] A system for the coordinated treatment of urban organic solid waste, comprising a kitchen waste storage unit, a sludge storage unit, a kitchen waste sorting unit connected to the kitchen waste storage unit, an anaerobic treatment unit connected to the kitchen waste sorting unit, a biogas treatment unit connected to the anaerobic treatment unit, a biogas residue treatment unit connected to the anaerobic treatment unit, a drying unit connected to the sludge storage unit, a separation unit connected to the drying unit, and an exhaust gas treatment unit and a solid residue treatment unit connected to the separation unit, wherein:

[0008] The food waste storage unit is used to receive food waste, the sludge storage unit is used to receive sludge, the food waste sorting unit is used to process the food waste into slurry, the anaerobic treatment unit is used to perform anaerobically treatment on the slurry, the biogas treatment unit is used to process the biogas generated when the anaerobic treatment unit performs anaerobically treatment on the slurry, and the biogas residue treatment unit is used to process the biogas generated when the anaerobic treatment unit performs anaerobically treatment on the slurry;

[0009] The drying unit is used to dry the sludge and / or biogas residue; the separation unit is used to separate the dried sludge and / or biogas residue into tail gas and solid residue; the tail gas treatment unit is used to treat the tail gas, and the solid residue treatment unit is used to treat the solid residue.

[0010] As a preferred embodiment of the above scheme, the anaerobic treatment unit includes an acidification tank connected to the food waste sorting unit and an anaerobic digestion tank connected to the acidification tank, and the acidification tank is used to pre-acidify the slurry; the anaerobic digestion tank is used to perform anaerobic treatment on the pre-acidified slurry.

[0011] As a preferred embodiment of the above scheme, the biogas processing unit includes a biogas filter connected to the anaerobic digester, a desulfurization tower connected to the biogas filter, and a gas storage cabinet connected to the desulfurization tower.

[0012] As a preferred embodiment of the above scheme, the biogas residue treatment unit includes a dehydration unit connected to the anaerobic digestion tank, and a wastewater treatment unit connected to the dehydration unit, and the dehydration unit is connected to the sludge storage unit.

[0013] As a preferred embodiment of the above scheme, the separation unit includes a double cyclone separator connected to the drying unit, and a bag dust collector connected to the double cyclone separator, and the bag dust collector is used to collect solid slag.

[0014] As a preferred embodiment of the above scheme, the exhaust gas treatment unit includes a condenser connected to the bag dust collector, a deodorization system connected to the condenser, and an activated carbon adsorption tower connected to the deodorization system.

[0015] As a preferred embodiment of the above scheme, the solid slag treatment unit includes a fluidized bed gasification furnace connected to the bag dust collector, a two-stage high-temperature separator connected to the fluidized bed gasification furnace, and a pyrolysis gas treatment unit and an ash treatment unit connected to the two-stage high-temperature separator.

[0016] As a preferred embodiment of the above scheme, the pyrolysis gas treatment unit includes a secondary combustion chamber connected to the two-stage high-temperature separator, and an air preheater connected to the secondary combustion chamber.

[0017] As a preferred embodiment of the above scheme, the ash processing unit includes an ash cooler connected to the two-stage high-temperature separator, and an ash storage connected to the ash cooler.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The urban organic solid waste coordinated treatment system disclosed in the present invention comprises a food waste storage unit, a sludge storage unit, a food waste sorting unit connected to the food waste storage unit, an anaerobic treatment unit connected to the food waste sorting unit, a biogas treatment unit connected to the anaerobic treatment unit, a biogas residue treatment unit connected to the anaerobic treatment unit, a drying unit connected to the sludge storage unit, a separation unit connected to the drying unit, a collection unit connected to the separation unit, an exhaust gas treatment unit and a solid residue treatment unit connected to the collection unit, etc., so as to achieve coordinated treatment of food waste and sludge, with a reduction of more than 90%, an organic matter degradation rate of more than 95%, and ash residue can also be used for making bricks, cement raw materials and other mature building materials, thereby achieving closed-loop management of food waste and sludge.

[0020] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites a preferred embodiment and describes it in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the urban organic solid waste collaborative treatment system of the present invention;

[0022] in, Figure 1 The reference numerals in the drawings are:

[0023] 1. Food waste storage unit; 2. Sludge storage unit; 3. Food waste sorting unit; 4. Acidification tank; 5. Anaerobic digestion tank; 6. Biogas filter; 7. Gas storage cabinet; 8. Dehydration unit; 9. Wastewater treatment unit; 10. Double cyclone separator; 11. Bag dust collector; 12. Condenser; 13. Deodorization system; 14. Activated carbon adsorption tower; 15. Fluidized bed gasification furnace; 16. Two-stage high-temperature separator; 17. Secondary combustion chamber; 18. Air preheater; 19. Ash cooler; 20. Ash storage; 21. Drying unit; 22. Desulfurization tower. DETAILED DESCRIPTION

[0024] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments:

[0025] like Figure 1 As shown, the urban organic solid waste coordinated treatment system disclosed in the present invention includes a food waste storage unit 1, a sludge storage unit 2, a food waste sorting unit 3 connected to the food waste storage unit 1, an anaerobic treatment unit connected to the food waste sorting unit 3, a biogas treatment unit connected to the anaerobic treatment unit, a biogas residue treatment unit connected to the anaerobic treatment unit, a drying unit 21 connected to the sludge storage unit 2, a separation unit connected to the drying unit 21, and an exhaust gas treatment unit and a solid residue treatment unit connected to the separation unit, wherein:

[0026] The food waste storage unit 1 is used to receive food waste, the sludge storage unit 2 is used to receive sludge, the food waste sorting unit 3 is used to process the food waste into slurry, the anaerobic treatment unit is used to perform anaerobically treatment on the slurry, the biogas treatment unit is used to process the biogas formed when the anaerobic treatment unit performs anaerobically treatment on the slurry, and the biogas residue treatment unit is used to process the biogas formed when the anaerobic treatment unit performs anaerobically treatment on the slurry.

[0027] The drying unit 21 is used to dry the sludge and / or biogas residue; the separation unit is used to separate the dried sludge and / or biogas residue into tail gas and solid residue; the tail gas treatment unit is used to treat the tail gas, and the solid residue treatment unit is used to treat the solid residue.

[0028] During operation, the food waste is transported into the food waste storage unit 1 by a special transport vehicle, and the sludge is transported into the sludge storage unit 2 by a special transport vehicle, and the food waste storage unit 1 is connected to the food waste sorting unit 3 through a multi-screw conveyor, and the multi-screw conveyor is arranged at the bottom of the food waste storage unit 1.

[0029] When the food waste sorting unit 3 processes the food waste into slurry, firstly, impurities such as plastic, metal, paper towel, fabric, bone, chopsticks, etc. in the food waste are removed by a coarse material sorting machine, and then the crusher of the food waste sorting unit 3 is used to perform multi-stage crushing screening to further separate heavy materials; then, the food waste is made into a coarse slurry by the pulping machine of the food waste sorting unit 3; then, the coarse slurry is desanded by a desander; finally, the coarse slurry is heated to 60-90° C. by the waste heat of the system, and the oil in the coarse slurry is separated by a three-phase separator to form a refined slurry, and then the separated oil is stored in a temporary storage tank, and then the oil stored in the temporary storage tank is reused or transported to a grease treatment plant; and the refined slurry is transported to the acidification tank 4.

[0030] The sludge storage unit 2 utilizes the centrifugal action of its centrifugal atomizer to convert the sludge and / or sludge into a small-particle atomized state, thereby increasing the heat exchange area between the sludge and / or sludge and the hot air flow, thereby quickly evaporating the moisture in the sludge and / or sludge; the drying unit 21 is a device specially developed to address the problems of high viscosity of dehydrated sludge, easy wall adhesion, clogging, and low heat exchange efficiency of traditional rotary or indirect heat exchange drying equipment. It increases the contact specific surface area between the sludge and / or sludge and the high-temperature flue gas through high-speed centrifugal atomization, and the heat exchange is sufficient and the time only takes 2 to 6 seconds. The entire drying system occupies a small area and has high working efficiency.

[0031] The anaerobic treatment unit includes an acidification tank 4 connected to the food waste sorting unit 3 and an anaerobic digestion tank 5 connected to the acidification tank 4, and the acidification tank 4 is used for pre-acidification treatment of the refined slurry; the anaerobic digestion tank 5 is used for anaerobic treatment of the pre-acidified refined slurry.

[0032] During operation, the refined slurry is hydrolyzed and acidified in the acidification tank 4 to be degraded into short-chain organic matter, and then enters the anaerobic digestion tank 5 to be further degraded into crude biogas and biogas residue through anaerobic reaction at a temperature of 35° C.-40° C.

[0033] The biogas processing unit includes a biogas filter 6 connected to the anaerobic digestion tank 5, a desulfurization tower 22 connected to the biogas filter 6, and a gas storage cabinet 7 connected to the desulfurization tower 22. During operation, the raw biogas is dehydrated and impurized by the biogas filter 6, and then undergoes iron oxide dry desulfurization treatment in the desulfurization tower 22 to become refined biogas, and then the refined biogas is stored in the gas storage cabinet 7. In addition, when the urban organic solid waste coordinated treatment system is under maintenance or shutdown due to a fault, the refined biogas stored in the gas storage cabinet 7 is sent to the torch for organized combustion and then safely discharged.

[0034] The digestate treatment unit includes a dehydration unit 8 connected to the anaerobic digestion tank 5 and a wastewater treatment unit connected to the dehydration unit 8, and the dehydration unit 8 is connected to the sludge storage unit 2. During operation, the digestate is processed by the dehydration unit 8 to form filtered water and filtered residue, the filtered residue produced during dehydration is transported to the sludge storage unit 2, and the filtered water is transported to the wastewater treatment unit for treatment to meet the wastewater discharge standard.

[0035] The separation unit includes a double cyclone separator 10 connected to the drying unit 21 and a bag dust collector 11 connected to the double cyclone separator 10, and the bag dust collector 11 is used to collect solid slag.

[0036] The tail gas treatment unit includes a condenser 12 connected to the bag dust collector 11, a deodorization system 13 connected to the condenser 12, and an activated carbon adsorption tower 14 connected to the deodorization system 13. During operation, after the tail gas is processed by the condenser 12, the heat contained in the tail gas can be recovered, and the recovered heat can be used for heating and heat preservation of the acidification tank 4 and the anaerobic digestion tank 5. At the same time, the tail gas after heat recovery passes through the deodorization system 13 and the activated carbon adsorption tower 14 in turn to meet the emission standards, and finally discharged through a fan, a chimney, etc.

[0037] The solid slag treatment unit includes a fluidized bed gasifier 15 connected to the bag filter 11 , a two-stage high-temperature separator 16 connected to the fluidized bed gasifier 15 , and a pyrolysis gas treatment unit and an ash treatment unit connected to the two-stage high-temperature separator 16 .

[0038] In the present invention, the air distribution plate of the fluidized bed gasifier 15 is a conical air distribution plate, and the lower wind chamber determines the air supply volume according to the upper conical air distribution plate. The conical air distribution causes the bed material to form an internal vortex in the fluidized bed gasifier 15 during the combustion and gasification process. The sludge and biomass in the dense phase zone undergo multiple cycles and have a long gasification residence time, which solves the problem of insufficient residence time in the dense phase zone caused by the high specific gravity of dry sludge and the low specific gravity of biomass, and realizes the synergistic effect of sludge and biomass gasification, which can greatly improve the bed gasification efficiency and fuel utilization rate, the gasification rate is greater than 85%, the thermal efficiency of the gasification system is greater than 90%, and the final residual carbon in the ash can be controlled within <5%.

[0039] The pyrolysis gas treatment unit includes a secondary combustion chamber 17 connected to the two-stage high-temperature separator 16 , and an air preheater 18 connected to the secondary combustion chamber 17 .

[0040] The ash treatment unit includes an ash cooler 19 connected to the two-stage high-temperature separator 16, and an ash bin 20 connected to the ash cooler 19. During operation, the ash cooler 19 can cool the ash produced by the two-stage high-temperature separator 16 and the secondary combustion chamber 17, so that the ash is cooled to below 100°C and then sent to the ash bin 20 for storage. The ash stored in the ash bin 20 is then regularly transported to external building materials utilization units for reuse, thereby ultimately achieving the reuse of the ash.

[0041] The following are specific embodiments of the present invention.

[0042] Embodiment 1

[0043] A central city with an urban population of about 500,000, the sewage plant produces 100 tons of dewatered sludge (80% water content) per day and 60 tons of food waste per day.

[0044] The working process of the urban organic solid waste collaborative treatment system is as follows:

[0045] (1) The wet sludge is transported to the sludge storage unit 2 by a closed transport vehicle and a high-concentration screw pump. The sludge storage unit 2 transports the sludge to the drying unit 21 for drying treatment to reduce the moisture content of the sludge to 20-30%, with a reduction of 26.3-29.8 tons.

[0046] (2) The double cyclone separator 10 and the bag dust collector 11 separate the sludge dried by the drying unit 21 into tail gas and solid residue. The solid residue is then transported to the fluidized bed gasifier 15 for gasification through a screw conveyor, a scraper conveyor, etc. At this time, the pyrolysis reaction temperature of the fluidized bed gasifier 15 is 600-800°C, and 12.0-13.2 tons of ash and pyrolysis gas are generated through the pyrolysis reaction.

[0047] (3) After the ash is cooled to 100° C. by the ash cooler 19 , it is transported to the ash storage 20 for storage and finally reused by cement plants and the like.

[0048] (4) The pyrolysis gas is transported to the secondary combustion chamber 17 and burned to generate high-temperature flue gas, which is then transported to the air preheater for storage. The high-temperature flue gas and cold air stored in the air preheater will be transmitted to the drying unit 21 for reuse.

[0049] After the sludge is treated by the urban organic solid waste coordinated treatment system, the reduction of the sludge is shown in Table 1:

[0050] Table 1 Sludge reduction

[0051]

[0052] (5) The food waste is transported and unloaded into the food waste storage unit 1 through the off-site collection and transportation system, and then the food waste is transported to the food waste sorting unit 3.

[0053] (6) The food waste sorting unit 3 crushes the food waste into slurry after sorting large substances, heavy substances, sand and gravel and other impurities, preheats the food waste to 80°C and removes oil through a three-phase separator to form a refined slurry, and then uses a screw pump to transfer the refined slurry to the acidification tank 4 and the anaerobic digestion tank 5. After the refined slurry undergoes two anaerobic treatments in the acidification tank 4 and the anaerobic digestion tank 5, the organic matter in the refined slurry is reduced by 60% to generate raw biogas and biogas liquid.

[0054] (7) The raw biogas is filtered by the biogas filter 6 and desulfurized by the desulfurization tower 22 to become refined biogas, which is then transported to the gas storage cabinet 7 for storage; finally, the refined biogas is sent to the secondary combustion chamber 17 by the Roots blower for reuse after pressure stabilization. In addition, the flare can also be used for maintenance and shutdown, and the biogas is discharged after safe treatment.

[0055] After the food waste is treated by the urban organic solid waste coordinated treatment system, the reduction of the food waste is shown in Table 2:

[0056] Table 2 Reduction of food waste

[0057]

[0058] Table 3 Energy consumption ratio of the process of the urban organic solid waste coordinated treatment system and the existing process

[0059]

[0060] As can be seen from Table 3, the urban organic solid waste collaborative treatment system utilizes sludge pyrolysis and gasification and anaerobic digestion of food waste for collaborative treatment. After anaerobic digestion of food waste, biogas of about 6000Nm3 is produced, which is purified and used to supplement the heat source of the pyrolysis and gasification system, thus achieving energy self-sustainability. The organic matter in the dry sludge and anaerobic filter residue of food waste is treated by the gasification system with a thermal degradation rate of more than 95%, the system reduction is greater than 90%, the organic matter degradation rate is greater than 95%, the pathogenic bacteria are 100% killed, and the harmlessness is complete. The entire process consumes 40-55Kw / ton of wet sludge (water content 80%) and 30-40Kw / ton of food waste (water content 85%). The heat energy is recycled and no primary energy is consumed. Compared with the sludge carbonization and food waste anaerobic digestion combined process of 75-80Kw / ton of wet sludge and 20-30kg / ton of wet sludge, the direct operating cost is reduced by more than 30%.

[0061] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A system for the coordinated treatment of urban organic solid waste, characterized in that: The invention comprises a kitchen waste storage unit, a sludge storage unit, a kitchen waste sorting unit connected to the kitchen waste storage unit, an anaerobic treatment unit connected to the kitchen waste sorting unit, a biogas treatment unit connected to the anaerobic treatment unit, a biogas residue treatment unit connected to the anaerobic treatment unit, a drying unit connected to the sludge storage unit, a separation unit connected to the drying unit, and an exhaust gas treatment unit and a solid residue treatment unit connected to the separation unit, wherein: The food waste storage unit is used to receive food waste, the sludge storage unit is used to receive sludge, the food waste sorting unit is used to process the food waste into slurry, the anaerobic treatment unit is used to perform anaerobically treatment on the slurry, the biogas treatment unit is used to process the biogas generated when the anaerobic treatment unit performs anaerobically treatment on the slurry, and the biogas residue treatment unit is used to process the biogas generated when the anaerobic treatment unit performs anaerobically treatment on the slurry; The drying unit is used to dry the sludge and / or digestate; the separation unit is used to separate the dried sludge and / or digestate into tail gas and solid residue; the tail gas treatment unit is used to treat the tail gas, and the solid residue treatment unit is used to treat the solid residue; the anaerobic treatment unit includes an acidification tank connected to the kitchen waste sorting unit and an anaerobic digestion tank connected to the acidification tank, and the acidification tank is used to pre-acidify the slurry; the anaerobic digestion tank is used to perform anaerobic treatment on the pre-acidified slurry; The biogas treatment unit includes a biogas filter connected to the anaerobic digester, a desulfurization tower connected to the biogas filter, and a gas storage cabinet connected to the desulfurization tower; the biogas residue treatment unit includes a dehydration unit connected to the anaerobic digester, and a wastewater treatment unit connected to the dehydration unit, and the dehydration unit is connected to the sludge storage unit; the separation unit includes a double cyclone separator connected to the drying unit, and a bag dust collector connected to the double cyclone separator, and the bag dust collector is used to collect solid residue; The exhaust gas treatment unit includes a condenser connected to the bag dust collector, a deodorization system connected to the condenser, and an activated carbon adsorption tower connected to the deodorization system; the solid slag treatment unit includes a fluidized bed gasifier connected to the bag dust collector, a two-stage high-temperature separator connected to the fluidized bed gasifier, and a pyrolysis gas treatment unit and an ash treatment unit connected to the two-stage high-temperature separator; the pyrolysis gas treatment unit includes a secondary combustion chamber connected to the two-stage high-temperature separator, and an air preheater connected to the secondary combustion chamber; the ash treatment unit includes an ash cooler connected to the two-stage high-temperature separator, and an ash storage connected to the ash cooler.

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