CN108410715B - High-solid methane production system for wood fiber raw material and process method thereof - Google Patents

Abstract

The invention discloses a wood fiber raw material high-solid methane production system and a process method thereof, wherein the wood fiber raw material high-solid methane production system comprises a pretreatment tank, an inoculum domestication device and a fermentation methane production device which are sequentially connected, wherein the inoculum domestication device is used for inoculating the domesticated inoculum and the wood fiber raw material to produce methane, and the produced fermentation liquor and water washing liquor are circularly led into the inoculum domestication device, and air outlets of the inoculum domestication device and the fermentation methane production device are connected with an exhaust pipe. The invention has simple process, wide adaptability, strong operability, low energy consumption and convenient system operation management and protection.

Description

A high-solid methane production system from lignocellulosic raw materials and its process method

Technical field

The invention belongs to the field of renewable energy development and utilization and environmental protection, and specifically relates to a high-solid methane production system from wood fiber raw materials and a process method thereof.

Background technique

Energy is an important guarantee for economic development and social progress, and it is also an important factor restricting the progress of human social civilization. Human society has developed from farming culture to the industrialization and information age, and the source of energy has gradually changed from firewood to an energy era dominated by fossil fuels such as coal and petroleum. However, due to the extensive use of fossil fuels, the energy originally stored in the interior of the earth has been reduced. Large amounts of carbon are released into the atmosphere, leading to increasing global warming. Particulate matter, nitrogen oxides, and sulfides released during the combustion of fossil fuels are also important sources of air pollution. Therefore, it is particularly urgent to develop clean and renewable new energy.

A considerable amount of biomass resources are produced on the earth every year. It is estimated that about 170 billion tons of new biomass resources are added to the earth every year, more than 80% of which are wood fiber raw materials, and crop straw alone reaches more than 2 billion tons every year. The main components of lignocellulosic raw materials are cellulose, hemicellulose and lignin. Among them, the sum of cellulose and hemicellulose accounts for 60% to 80% of the dry matter mass of lignocellulosic raw materials, and the lignin content accounts for 5% to 20%. . Converting lignocellulosic raw materials into methane-based biogas through biotechnological means is an important direction for resource utilization of lignocellulosic raw materials. While obtaining clean energy, the fermented biogas slurry is also a high-quality organic fertilizer that can be used for cultivation. Fertilize the soil and realize the recycling of carbon and nitrogen resources without causing secondary pollution.

Anaerobic biological methane production technology from organic solid materials can be divided into wet fermentation, high solid fermentation and dry fermentation according to the different dry matter concentrations of the fermentation substrate in the fermentation system. The corresponding dry matter concentrations of the fermentation substrate in the fermentation system are: ≤10%, 10%～20%, ≥20%. In biogas projects, the corresponding fermentation process and device type are selected based on the physical and chemical properties of the materials. Since the moisture content of lignocellulosic raw materials is generally low, generally less than 90%, and for crop straws, it is even lower than 40%. Therefore, for biogas projects that use lignocellulosic raw materials as the main fermentation substrate, high solid fermentation or dry fermentation is used. It is more conducive to saving water and reducing consumption, reducing operating costs and reducing secondary pollution. In recent years, the use of high solids and dry fermentation technology to process lignocellulosic raw materials has received increasing attention, and some demonstration projects have been built. However, there are still some problems, such as there is almost no fermentation liquid in the high solids and dry fermentation process. The demand for inoculum is large, the source of inoculum becomes a problem, and how to achieve rapid and uniform inoculation of lignocellulosic raw materials in high solids and dry fermentation is difficult to achieve.

In view of the problems of high solids of lignocellulosic raw materials and dry anaerobic fermentation, such as large amount of inoculum, limited inoculum sources, and difficulty in rapid and uniform inoculation, there is an urgent need for a high-solid methane production device of lignocellulosic raw materials to achieve the goal of obtaining It has good results in terms of highly active inoculum, uniform and rapid inoculation and stable supply of inoculum.

Contents of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a high-solid methane production system from lignocellulosic raw materials and a process method thereof. The purpose is to provide inoculum with stable performance and sufficient yield for high-solid fermentation of lignocellulosic raw materials, and to achieve mixing of the inoculum and lignocellulosic raw materials. .

In order to achieve the above objects, the technical solutions adopted by the present invention are:

A high-solid methane production system for lignocellulosic raw materials, including a pretreatment tank connected in sequence, an inoculum acclimation device, and a device for inoculating the domesticated inoculum and lignocellulosic raw materials to produce methane and circulating the produced fermentation liquid and water washing liquid. A fermentation methanogenesis device of the inoculum acclimation device, the air outlets of the inoculum acclimation device and the fermentation methanogenesis device are both connected to the exhaust pipe.

The pretreatment tank is divided into multiple pool bodies, and organic wastewater sequentially overflows from the pool body at the inlet end of the pretreatment pool to the pool body at the outlet end.

The pool body has three compartments, which are the first compartment pool body, the second compartment pool body and the third compartment pool body which are arranged in sequence from the inlet end of the pretreatment tank to the outlet end. The first compartment pool body is provided with Solid waste collection mesh bag, feed pipe located above the mesh bag and hanger for fixing the mesh bag. The net bag can be made of any one of barbed wire, fishing net or plastic net, and a hanger is provided on the inner upper part of the first pool body for fixing the net bag. A water outlet is provided at the bottom of the third compartment of the pretreatment tank, and the water is pumped into the inoculum acclimation device. Organic wastewater can be one or more of rural domestic sewage, livestock and poultry breeding wastewater, soy product processing wastewater, slaughtering wastewater, toilet wastewater, etc. Perishable organic solid waste can be food waste, kitchen waste, vegetable waste, livestock waste, etc. One or more of poultry manure, sludge, etc. Set up a rain shelter on the top of the pretreatment tank, which can be made of colored steel tiles, iron sheets, aluminum sheets, plastic plates, plexiglass or plastic greenhouses.

The inoculum acclimation device is a continuous stirred tank reactor (Continuous Stirred Tank Reactor, CSTR) or an upflow anaerobic solids reactor (Upflow Solids Reactor, USR).

The water inlet of the inoculum acclimation device is located at the bottom of the side, and the water outlet is located at about 1/3 of the effective height of the device. A valve is installed at the water outlet. The generated biogas is collected through pipelines and then processed centrally.

Using the USR device, the water outlet position should be moved downwards to 1/3 to 1/2 of the height of the fermentation device (from top to bottom), and porous materials, such as gravel and crushed materials, should be loaded from the bottom of the fermentation tank to 1/3 of the height. One or more of stone, Boer ring, bellows, honeycomb tube, soft nylon fiber filter material, semi-soft polyethylene, polypropylene filter material, elastic polystyrene filter material, etc.

A heating and insulation structure is set up in the inoculum acclimation device. The heating and insulation device is the same as a conventional anaerobic fermentation device. The heating method can be one or more of biogas/biomass boilers, solar panels, ground source heat pumps and other heat sources. In this combination, the insulation structure can use one or more of a greenhouse or insulation blanket for the top, hollow bricks, extruded boards, polyurethane foam, styrene board, furnace ash, rock wool, etc. for the bottom and side walls. The fermentation temperature is 25℃～37℃.

The inoculum acclimation device is provided with a filter material layer, the filter material layer is arranged upward from the bottom of the inoculum acclimation device, and the thickness of the filter material layer does not exceed 1/3 of the height of the inoculum acclimation device.

A liquid level observation port is provided on the side of the inoculum acclimation device.

The fermentation methane production device includes a plurality of garage-type biological methane production devices connected in parallel. The garage-type biological methane production device includes a fermentation unit, a spray mechanism, a fermentation liquid collection ditch and a lignocellulose raw material located in the fermentation unit. The inoculum domesticated by the inoculum domestication device is sprayed onto the pile of wood fiber raw materials through a spray mechanism. The air outlet of the fermentation unit is connected to the exhaust pipe. A second water pump is set up to circulate the fermentation liquid collected in the fermentation liquid collection ditch. The recovery tube is pumped into the inoculum acclimation device.

The fermentation methane production device also includes an air guide pipe, and the air guide pipe is installed in the wood raw material pile. The air guide tube adopts polyvinyl chloride tube, polyethylene tube or polypropylene tube. Preferably, drill a number of small holes in the pipe wall with a hole diameter of 4 mm to 10 mm.

The fermentation liquid collection ditch is located in the middle of the bottom of the fermentation unit. The top of the fermentation liquid collection ditch is provided with a porous baffle and a filter. Both sides of the bottom of the fermentation unit are inclined toward the middle with an inclination angle of 5 to 10°.

The height of the fermentation unit shall not exceed 2/3 of the effective height of the inoculum acclimation device, and the dry matter concentration of lignocellulosic raw materials in the fermentation device shall be 10% to 30%.

The lignocellulosic raw material can be one or more of agricultural straw, garden pruning waste, wood processing waste, edible fungus scraps, vegetable waste, and litter. The agricultural straw can be collected bundled straw and directly used for fermentation. Produces biogas.

The process method for producing methane by the system includes the following steps:

Step 1: The organic wastewater is pretreated through the pretreatment tank;

Step 2. The organic wastewater treated in Step 1 enters the inoculum acclimation device to acclimate the inoculum;

Step 3: The domesticated inoculum enters the fermentation methanogenesis device, and the lignocellulosic raw materials in the fermentation methanogenesis device are inoculated to produce methane; the fermentation liquid and water washing liquid produced by the fermentation methanogenesis device are introduced into the inoculum domestication device for activation and recirculation. .

The raw material of the inoculum acclimation device can be organic wastewater. For projects without sufficient organic wastewater in the surrounding area, the anaerobic substances attached to the surface of the lignocellulosic raw materials can be sprayed into the fermentation device during the gas production stage of the lignocellulosic raw material garage-type fermentation unit. The aerobic microorganisms are washed out, and the effluent flows back into the inoculum acclimation device, and a small amount of nutrients are added to the inoculum acclimation device to meet the needs of anaerobic microbial metabolism and proliferation.

Gas outlets are provided at the tops of the inoculum acclimation device and the lignocellulosic raw material high-solid biomethane production device respectively. The generated biogas is collected and used for power generation or heat supply after dehydration and desulfurization.

The pretreatment tank, the inoculum acclimation device and the lignocellulose raw material garage-type biomethane production device are connected in series through pipelines. The height of the lignocellulose raw material garage-type biomethane production device does not exceed 2/3 of the effective height of the inoculum acclimation device, and the inoculum acclimation device 1/3 of the drainage volume of the device is enough to inoculate a garage-type fermentation unit for lignocellulosic raw materials. Set valves at the water outlet of the pretreatment tank, the inoculum acclimation device and the lignocellulosic raw material garage-type biomethane production device, as well as the water inlet of the lignocellulosic raw material garage-type biomethane production device. A valve is provided at the outlet of the biological methane production unit, and a tee is provided between the water outlet of the inoculum acclimation device and the main water inlet of the garage-type biomethane production device for wood fiber raw materials. One end of the tee is connected to the inoculum acclimation device and the other end is connected to the wood fiber. The other end of the raw material garage-type biomethane production device is connected to clean water, which can be clean river water, tap water or well water. Water pumps are respectively installed at the water outlet of the pretreatment tank and the water inlet of the garage-type biomethane production device for lignocellulosic raw materials where the fermentation liquid returns to the inoculum acclimation device.

Beneficial effects of the present invention:

1. Simple process, wide adaptability, strong operability, low energy consumption, and convenient system operation and maintenance.

2. Continuously produce inoculum with high activity and stable performance to meet the continuous demand for inoculum for high-solid anaerobic digestion of lignocellulosic raw materials with low moisture content. The inoculation has high uniformity, simple inoculation process and low cost.

3. Wide adaptability to raw materials, which can simultaneously meet the treatment needs of solid waste with low moisture content such as lignocellulosic raw materials and liquid waste such as livestock and poultry breeding sewage, and lignocellulosic raw materials do not require any pretreatment, greatly reducing the operating costs.

4. The parallel connection of multiple fermentation units ensures that the daily gas production of the entire system is relatively stable and meets the needs of processing large quantities of lignocellulosic raw materials.

5. After the system operates stably, not only will there be no biogas slurry produced, there will be no problems with wastewater discharge and treatment, but it can also absorb a considerable amount of organic wastewater.

Description of drawings

This manual includes the following drawings, which show:

Figure 1 is a schematic structural diagram of the present invention;

Figure 2 is a schematic structural diagram of the garage-type biomethane production device of the present invention;

Figure 3 is a partial cross-sectional view of the garage-type biomethane production device of the present invention;

Figure 4 is a schematic structural diagram of the pretreatment tank.

Marked in the picture are:

1. Pretreatment tank, 2. Feed pipe, 3. Hanger, 4. Mesh bag, 5. First water pump, 6. First water valve, 7. Inoculum acclimation device, 8. First air valve, 9 , first exhaust pipe; 10. second water valve, 11. three-way valve, 12. third water valve, 13. garage-type biological methane production device, 14. second exhaust pipe, 15. second air valve , 16. Fermentation liquid collection ditch, 17. Fourth water valve, 18. Second water pump, 19. Air guide tube, 20. Spray mechanism, 21. Sealing door.

Detailed ways

The specific implementation modes of the present invention will be further described in detail below by describing the embodiments with reference to the accompanying drawings. The purpose is to help those skilled in the art have a more complete, accurate and in-depth understanding of the concepts and technical solutions of the present invention, and contribute to its implementation.

As shown in Figures 1 to 4, a high-solid methane production system for lignocellulosic raw materials includes a sequentially connected pretreatment tank 1, an inoculum acclimation device 7 and a device for inoculating the domesticated inoculum and lignocellulosic raw materials to produce methane. The garage-type biomethane production device 13, the inoculum acclimation device 7 and the gas outlet of the biomethane production device 13 are respectively connected with the first exhaust pipe 9 and the second exhaust pipe 14, the first exhaust pipe 9 and the second row The gas pipes 14 are connected in series, and the generated biogas can be collected, dehydrated and desulfurized and then used for power generation or purified before entering the city gas pipeline network.

The pretreatment tank 1 is divided into multiple pool bodies. The organic wastewater overflows from the pool body at the inlet end 2 of the pretreatment pool and flows to the pool body at the outlet end. Specifically, the height of the pool body near both ends of the inlet and outlet is relatively high, and the height of the side wall of the pool body between the two ends is gradually reduced, which facilitates the gradual overflow of wastewater in the pool body.

The pretreatment tank body can be divided into three compartments, which are the first compartment tank body, the second compartment tank body and the third compartment tank body which are arranged in sequence from the inlet end to the outlet end of the pretreatment tank 1. The first compartment tank body It is provided with a solid waste collection mesh bag 4, a feed pipe 2 located above the mesh bag, and a hanger 3 for fixing the mesh bag. It meets the needs of removing scum and large suspended solids, and can simultaneously meet the needs of feeding organic wastewater and perishable organic solid waste. The mesh bag 4 can be made of any one of barbed wire, fishing nets or plastic nets. In the second A hanger 3 is provided on the inner upper part of the pool body, and the mesh bag 4 is fixed on the hanger 3. The hanger 3 and the mesh bag 4 are preferably connected in a detachable connection; the organic wastewater enters the pretreatment pool through the mesh bag 3 from the feed pipe 2 above the first compartment body. The mesh bag is used to store a small amount of perishable organic solid waste. , the organic solid waste in the mesh bag is washed and leached by the organic wastewater, and the easily decomposable organic matter in the organic solid waste enters the organic wastewater. A water outlet is provided at the bottom of the third compartment of the pretreatment tank 1, and the water is pumped into the inoculum acclimation device 7 through the first water pump 5. A third feeding pipe is provided between the first water pump 5 and the inoculum acclimation device 7. A water valve 6 is used to control whether to feed the inoculum acclimation device 7. Organic wastewater can be one or more of rural domestic sewage, livestock and poultry breeding wastewater, soy product processing wastewater, slaughtering wastewater, toilet wastewater, etc. Perishable organic solid waste can be food waste, kitchen waste, vegetable waste, livestock waste, etc. One or more of poultry manure, sludge, etc. A rain shelter is set on the top of the pretreatment tank 1, which can be made of colored steel tiles, iron sheets, aluminum sheets, plastic plates, organic glass or plastic greenhouses.

The inoculum acclimation device can be a continuous stirred tank reactor (Continuous Stirred Tank Reactor, CSTR) or an upflow anaerobic solids reactor (Upflow Solids Reactor, USR).

The water inlet of the inoculum acclimation device 7 is located at the bottom of the side, and the water outlet is located at about 1/3 of the effective height of the device. A second water valve 10 is provided at the water outlet. The generated biogas is collected through the first exhaust pipe 9 and then concentrated. deal with. If a USR device is used, the water outlet needs to be moved downward appropriately, located at 1/3 to 1/2 of the height of the inoculum acclimation device 7 (from top to bottom), and installed between the bottom of the inoculum acclimation device 7 and 1/3 of the height. Into porous materials, such as gravel, gravel, Bohr rings, bellows, honeycomb tubes, soft nylon fiber filter material, semi-soft polyethylene, polypropylene filter material, elastic polystyrene filter material, etc. or Various.

In order to meet the heating and insulation needs of the inoculum acclimation device, a heating and insulation structure can be set up. The heating and insulation device is the same as a conventional anaerobic fermentation device. The heating methods can be biogas/biomass boilers, solar panels, ground source heat pumps, and One or several combinations of other heat sources. The insulation structure can use a greenhouse or insulation blanket for the top, and hollow bricks, extruded boards, polyurethane foam, styrene boards, furnace ash, rock wool, etc. for the bottom and side walls. Kind or variety. The inoculum acclimation device 7 is provided with a filter material layer. The filter material layer is arranged upward from the bottom of the inoculum acclimation device, and the thickness of the filter material layer does not exceed 1/3 of the height of the inoculum acclimation device 7 to increase anaerobic content in the device. Number of microorganisms. The filter material layer uses porous materials, such as gravel, gravel, Bohr rings, bellows, honeycomb tubes, soft nylon fiber filter materials, semi-soft polyethylene, polypropylene filter materials, elastic polystyrene filter materials, etc. one or more.

The side of the inoculum acclimation device 7 is provided with a liquid level observation port, which can observe the liquid level height in the inoculum acclimation device at any time. The liquid level height should not be higher than 85% of the total height of the inoculum acclimation device. Inoculation should be carried out when the liquid level is too high. Object discharge operation. The inoculum acclimation device 7 adopts the method of batch discharge, that is, a certain amount of inoculum is discharged from the inoculum acclimation device in batches when the subsequent unit needs to use the inoculum.

The fermentation methane production device includes multiple parallel-connected garage-type biological methane production devices. The garage-type biological methane production device includes a fermentation unit 13, a spray mechanism 20, a fermentation liquid collection ditch 16, an air guide tube 19 and a gas conductor located in the fermentation unit. The lignocellulosic raw materials in 13, the inoculum domesticated by the inoculum acclimation device 7 are sprayed onto the pile formed of lignocellulosic raw materials through the spray mechanism 20, and the second exhaust pipe 14 and the first exhaust pipe 9 of the fermentation unit 13 connection, a second water pump 18 is set up to collect the fermentation liquid collected in the fermentation liquid collection ditch 16 through a pipeline and then pump it into the inoculum acclimation device 7 through the second water pump 18. The air guide tube 19 is located in the wood raw material pile body. The air guide tube 19 adopts polyvinyl chloride tube, polyethylene tube or polypropylene tube. Preferably, drill a number of small holes in the pipe wall with a hole diameter of 4 mm to 10 mm. The spray mechanism 20 can use multiple nozzles to evenly spray the inoculum onto the wood fiber pile through the nozzle at the top of the fermentation unit. The inoculum reaches the pile along with the air guide tube 19 in the pile and the infiltration of the pile. All parts of the body, and full contact between the inoculum and the lignocellulosic raw materials is achieved through the continuous multiple reflux of the inoculum. A fermentation liquid collection ditch 16 is provided in the middle of the bottom of the fermentation unit. There are porous baffles and filters on the top of the fermentation liquid collection ditch 16. Both sides of the bottom of the fermentation unit are tilted to a certain angle toward the middle, with an inclination angle of 5 to 10° (according to the width of the fermentation device). (Appropriate adjustment), the fermentation broth of the lignocellulosic raw material pile is finally collected into the fermentation broth collection ditch 16, and the water from the fermentation broth collection ditch 16 is pumped to the inoculum acclimation device 7 through the second water pump 18 to realize the regeneration of the inoculum. Insulation measures should be provided around and at the bottom of the garage-type biomethane production device using wood fiber raw materials. Preferably, the height of the fermentation unit does not exceed 2/3 of the effective height of the inoculum acclimation device, and the dry matter concentration of lignocellulosic raw materials in the fermentation device is between 10% and 30%.

The above-mentioned lignocellulosic raw materials can be one or more of agricultural straw, garden pruning waste, wood processing waste, edible fungus scraps, vegetable waste, and litter. The agricultural straw can be collected bundled straw and directly used for fermentation. Produces biogas.

The process for producing methane using the above system includes the following steps:

Step 1: The organic wastewater is pretreated through the pretreatment tank;

Step 2. The organic wastewater treated in Step 1 enters the inoculum acclimation device to acclimate the inoculum;

Step 3: The domesticated inoculum enters the fermentation methanogenesis device, and the lignocellulosic raw materials in the fermentation methanogenesis device are inoculated to produce methane; the fermentation liquid and water washing liquid produced by the fermentation methanogenesis device are introduced into the inoculum domestication device for activation and recirculation. .

Specifically, organic domestic waste, vegetable waste, livestock and poultry manure, etc. are put into mesh bags and soaked in wastewater for a period of time. The solid waste in the mesh bags is regularly replaced. The wastewater and solid organic waste hydrolyzate are pretreated in the pretreatment tank 1. After treatment, the first water pump 5 is used to pump the inoculum into the inoculum acclimation device 7 through the first valve 6 . A filter material layer is provided below 1/3 of the inoculum acclimation device 7 to increase the number of anaerobic microorganisms in the device. An inoculum discharge pipe and a first discharge valve 5 are provided at about 2/3 of the height of the inoculum acclimation device 7. When the inoculum needs to be used, the inoculum enters the lignocellulosic raw material through the inoculum discharge pipe and the second water valve 10. Inside the garage-type fermentation unit 13. An air outlet is provided at the top of the inoculum acclimation device 7 and is connected to the exhaust main pipe through a first exhaust pipe. A first air valve 8 is provided on the first exhaust pipe. Open the first air valve 8 to generate the inoculum acclimation device. The biogas is discharged through the first exhaust pipe. A third water valve 12 is provided at the inoculum inlet of each garage-type fermentation unit 13. The third water valve 12 is normally closed and is only opened when the fermentation unit needs to add inoculum. The lignocellulosic raw materials are loaded mechanically or manually from the sealed door 21 of the fermentation unit 13, and several air guide tubes 19 are inserted into the pile of lignocellulosic raw materials. A spray mechanism 20 is provided on the top of the fermentation unit 13. The spray mechanism is connected to the inoculum access pipe. The inoculum spray mechanism can achieve uniform spraying of the inoculum and control the speed of inoculum spraying. When the fermentation unit is started, open the second air valve 15 on the second exhaust pipe, open the spray mechanism 20, and fully contact the inoculum with the lignocellulosic raw materials in the fermentation unit. In the first 3 days after the fermentation unit 13 is started, The inoculum in the fermentation unit 13 is regularly refluxed, and the second air valve 15 needs to be closed during reflux. A fermentation liquid collection ditch 16 is provided in the middle of the bottom of the fermentation unit 13. An incline is provided along the edge of the fermentation unit 13 toward the fermentation liquid collection ditch 16 to facilitate the guided outflow of the fermentation liquid. The inclination angle θ is 5 to 10°. In the fermentation liquid collection ditch 16 A fourth water valve 17 is provided at the water outlet. After the four water valve 17 is opened, the fermentation liquid in the fermentation liquid collection ditch 16 is pumped to the inoculum acclimation device 7 for regeneration through the second water pump 18 .

When the amount of external sewage is small or insufficient, in order to meet the demand for inoculum in the anaerobic fermentation of lignocellulosic raw materials, the three-way valve 11 is opened and clean water (tap water or unpolluted river water) is pumped into the fermentation unit that has stopped producing gas. The anaerobic microorganisms attached to the surface of the lignocellulosic raw materials are washed down and returned to the inoculum acclimation device 7. At the same time, nutrients such as carbon, nitrogen, phosphorus, iron, cobalt, and nickel are replenished into the inoculum acclimation device 7 to ensure that the inoculum stable supply. When the amount of wastewater is small, you can also manually pump the wastewater in the third compartment of the pretreatment tank 1 into the first compartment, and use the microorganisms in the wastewater to accelerate the hydrolysis of solid organic matter. At the same time, in the third compartment Add a small amount of tap water or unpolluted river water. An air outlet pipe is provided on the top of the inoculum acclimation device 7 and the garage fermentation unit 13 to collect the generated biogas. The air outlet pipes are connected in parallel and each has a corresponding valve control. The collected biogas is used for power generation or heating after dehydration and desulfurization.

The high-solid methane production system of wood fiber raw materials of the present invention and its processing and manufacturing are simple and convenient, and can be processed and manufactured as shown in the accompanying drawings of the description. The thermal insulation system of this device is the same as that of an ordinary biogas fermentation device. Except for the technical features described in the manual, they are all technologies known to those in the field.

The beneficial effects of the present invention will be further described below through examples.

Example 1

One organic glass tank with a total volume of 12L (diameter 18cm, height 45cm) and three organic glass tanks with a total volume of 5L (diameter 15cm, height 30cm) were used as the inoculum acclimation device and the high-solid methanogenesis system of lignocellulosic raw materials respectively. First, the pig farm wastewater was used as organic wastewater, and the biogas residue from a well-run biogas project in the pig farm was used as the inoculum to start the inoculum acclimation device. The hydraulic retention time of the pig farm wastewater was 20 days, and the fermentation temperature was (37±1)°C. After the inoculum acclimation device, three straw high-solid fermentation tanks are connected in sequence. Each fermentation tank is filled with kneaded wheat straw with a dry matter weight of 300g (chopped to 2-3cm after air-drying), sealed, and placed at (37±1) Experiments were carried out at ℃. When the inoculum in the inoculum acclimation device reaches 80% of the total volume of the fermentation tank, approximately 2.7L of inoculum will be discharged at one time and pumped into the first straw high solids fermentation tank through a peristaltic pump. Considering that water absorption by straw is a slow process, a lot of the added inoculum goes directly to the bottom of the tank. Therefore, while adding the inoculum, a peristaltic pump is used to pump the inoculum at the bottom of the fermentation tank back to the inoculum acclimation device, and the return flow is 2 times a day. reflux continuously for 3 days. After 3 days, the straw high-solid methane production system has produced biogas normally. After that, the second and third straw fermentation tanks are started in sequence according to the above method. Ensure that the inoculum is used before starting a new straw fermentation tank each time. The total amount of inoculum in the acclimation tank has exceeded the total capacity of the inoculum acclimation device by more than 80%. The stable gas production period of the straw fermentation tank is about 30 days, and then the daily gas production gradually decreases. When the volumetric gas production is lower than 0.2m ³ .m ^-3 .d ^-1 , part of the inoculum is released from the inoculum acclimation tank and enters the straw fermentation tank. Adjust the straw dry matter concentration in the straw fermentation tank to about 5%, and "stir" the straw fermentation tank through the internal circulation of the fermentation liquid. The daily gas production will increase significantly the next day, and the high gas production will be maintained for about 10 days. After that, the gas production gradually decreased. When the volumetric gas production was lower than 0.05m ³ .m ^-3 .d ^-1 , the experiment was stopped. All the fermentation liquid in the straw fermentation tank was pumped into the inoculum acclimation tank to continue acclimation before use. During the experiment, gas production and methane content were measured every day.

In this example, the total operation period of the straw fermentation tank is 50 days. The average cumulative gas production of straw in the three fermentation tanks is (310±15) mL. The average volume fraction of methane is 56.62%±0.54%. The gas production of the three devices is parallel. OK, no acidification occurred.

Example 2

This experiment was continued with the inoculum in the inoculum acclimation device of Example 1. The inoculum acclimation device and lignocellulose raw material high-solid methanogenesis system used were the same as Example 1. First, the pig farm wastewater is used as organic wastewater to start the inoculum acclimation device. After the inoculum acclimation device, three straw high-solid fermentation tanks are connected in sequence, and 300g of wheat straw with a dry matter mass of 300g (air-dried and chopped) is added to each straw fermentation tank. to 2-3cm), conduct the experiment at (37±1)℃ after sealing. When the inoculum in the inoculum acclimation device reaches 80% of the total volume of the fermentation tank, approximately 2.7L of inoculum is discharged at one time and pumped into the first straw high-solids fermentation tank through a peristaltic pump, and then the inoculum in the fermentation tank is refluxed for 3 days. , the reflow method is the same as Example 1. Since there is no external organic wastewater afterwards, the inoculum acclimation device has no external organic wastewater to replenish. When the gas production of the first straw fermentation tank ends, first pump the entire amount of fermentation liquid in the fermentation tank back to the inoculum acclimation device, then slowly add 1.5L of tap water into the straw fermentation tank, and the generated leachate is directly pumped through the peristaltic pump. Return to the top of the straw fermentation tank. Continue to reflux for about 30 minutes. Pump the entire amount of the washing solution into the inoculum acclimation device. At the same time, add self-prepared nutrient solution (composed of glucose, ammonium bicarbonate, potassium superphosphate and a small amount of trace elements) into the inoculum acclimation device. Daily Add a small amount of nutrient solution to the inoculum acclimation device. One week later, approximately 2.7L of inoculum was discharged from the inoculum acclimation device at one time into the second straw fermentation tank. Other operations were the same as the first fermentation tank. When the gas production in the second straw fermentation tank ends, add tap water to clean the anaerobic microorganisms, operate the same as the first fermentation tank, and then run the third and fourth fermentation tanks. During the experiment, gas production and methane content were measured every day.

In this example, the total operating period of the straw fermentation tank is 55 days. The maximum daily gas production is slightly lower than that in Example 1. The time required to reach the peak gas production is 3-5 days longer than that in Example 1. Three fermentation tanks (the first fermentation tank The average cumulative gas production of straw within the plant (not included) is (302±18) mL, and the average volume fraction of methane is 55.44%±0.68%. The gas production of the three devices is in good parallelism, and no acidification occurs.

The present invention has been exemplarily described above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above manner. As long as various non-substantive improvements are made using the method concepts and technical solutions of the present invention; or the above-mentioned concepts and technical solutions of the present invention are directly applied to other situations without improvement, they all fall within the protection scope of the present invention. within.

Claims (8)

1. A high-solid methane production system from lignocellulosic raw materials, characterized by: including a pretreatment tank connected in sequence, an inoculum acclimation device, and a fermentation device for inoculating the domesticated inoculum and lignocellulosic raw materials to produce methane and to generate methane. The liquid and washing liquid are circulated and introduced into the fermentation methane-producing device of the inoculum acclimation device, and the air outlets of the inoculum acclimation device and the fermentation methane-producing device are connected to the exhaust pipe; The fermentation methane production device includes a plurality of garage-type biological methane production devices connected in parallel. The garage-type biological methane production device includes a fermentation unit, a spray mechanism, a fermentation liquid collection ditch and a lignocellulose raw material located in the fermentation unit. The inoculum domesticated by the inoculum domestication device is sprayed onto the pile of wood fiber raw materials through a spray mechanism. The air outlet of the fermentation unit is connected to the exhaust pipe. A second water pump is set up to circulate the fermentation liquid collected in the fermentation liquid collection ditch. The recovery pipe is pumped into the inoculum acclimation device; the fermentation methane production device also includes an air guide tube, which is located in the wood fiber raw material pile, and has a number of small holes in the wall of the tube. Aperture diameter is 4mm~10mm; A tee is provided between the water outlet of the inoculum acclimation device and the main water inlet of the garage-type biological methane production device for wood fiber raw materials. One end of the tee is connected to the inoculum domestication device, one end is connected to the garage-type biological methane production device for wood fiber raw materials, and the other end is connected to the inoculum acclimation device. Connect to clean water. 2. The high-solid methane production system for lignocellulosic raw materials according to claim 1, characterized in that: the pretreatment tank is divided into multiple pool bodies, and organic wastewater sequentially overflows from the pool bodies at the feed port end of the pretreatment pool to the discharge. The pool body at the mouth end. 3. The high-solid methane production system for wood fiber raw materials according to claim 2, characterized in that: the pool body has three compartments, which are the first compartments arranged sequentially from the feed end of the pretreatment tank to the outlet end. The first pool body is provided with a solid waste collection mesh bag, a feed pipe located above the mesh bag and a hanger for fixing the mesh bag. 4. The high-solid methanogenesis system for lignocellulosic raw materials according to claim 1, characterized in that: the inoculum acclimation device is a continuous stirred tank reactor or an upflow anaerobic solid reactor. 5. The high-solid methane production system from lignocellulosic raw materials according to claim 4, characterized in that: the inoculum acclimation device is provided with a filter material layer, and the filter material layer is arranged upward from the bottom of the inoculum acclimation device, and The thickness of the filter material layer shall not exceed 1/3 of the height of the inoculum acclimation device. 6. The high-solid methane production system from lignocellulosic raw materials according to claim 1, characterized in that: a liquid level observation port is provided on the side of the inoculum acclimation device. 7. The high-solid methane production system for lignocellulosic raw materials according to claim 1, characterized in that: the fermentation liquid collection ditch is located in the middle of the bottom of the fermentation unit, and the top of the fermentation liquid collection ditch is provided with a porous baffle and a filter. The two sides of the bottom of the unit are inclined toward the middle, with an inclination angle of 5 to 10°. 8. A process for producing methane using the system of any one of claims 1 to 7, characterized in that it includes the following steps: Step 1: The organic wastewater is pretreated through the pretreatment tank; Step 2. The organic wastewater treated in Step 1 enters the inoculum acclimation device to acclimate the inoculum; Step 3: The domesticated inoculum enters the fermentation methanogenesis device, and the lignocellulosic raw materials in the fermentation methanogenesis device are inoculated to produce methane; the fermentation liquid and water washing liquid produced by the fermentation methanogenesis device are introduced into the inoculum domestication device for activation and recirculation. .