There are generally two kinds of biogas digesters, one is ordinary cement and the other is glass fiber reinforced plastic, which are divided into ordinary and patented types.
I specialize in FRP biogas digesters in Xinjiang, which is a patented product.
The price of cement is slightly lower, but the construction time is long, so gas cannot be produced in winter, and groundwater level is needed.
I. Product Features
1, molded products, easy to install. This product belongs to industrial molding products, and the installation time is only a few hours. After installation, it can be used as a filler the next day.
2. Lightweight and convenient transportation. The total weight of a pool is only one or two hundred kilograms, which is made separately and convenient for transportation.
3. Advanced technology and reasonable design. Adopt ellipsoid volume, buried depth, large fermentation bottom, convenient for special circulation of feces, no fermentation blind area, automatic slag discharge and high gas production.
4. The tank has good sealing performance and high strength. Determined by the performance of FRP, combined with the use of special composite materials, its strength, sealing, pressure resistance, aging resistance, wear resistance and heat insulation are stronger than those of concrete biogas digesters.
5, the pool body does not crack and has a long service life. The pool body will never crack, and there is no need for maintenance during use, and the service life can be as long as 20 years.
6. The swimming pool is low in cost and price. The product price is at a low price among similar products in the same industry. Although the price is higher than building a concrete biogas digester, its gas production is high, it does not need maintenance, its service life is long, and it is cost-effective to calculate the general ledger.
Second, the installation program
(1) site selection
When choosing the installation location, we should first consider the combination with the bathroom, pigsty and kitchen. It is necessary to facilitate the excrement from toilets and pigsty to flow into the inlet of biogas digester, and biogas residue and biogas slurry to flow into vegetable fields from the outlet. The gas outlet of biogas digester is introduced into the kitchen, and the length of gas transmission pipeline is controlled within 30m to avoid too long pipeline and insufficient air pressure. In addition, we should also pay attention to avoid areas where roots and gravel gather.
(2) Digging a pit
1. Dig a pit at the selected location (please dig the pit according to the size shown in the attached figure). The diameter of the upper hemisphere of the pit is larger, and the bottom of the pit should be dug into the shape of the bottom of the FRP biogas digester. The entrance and exit should be dug according to its shape and size, so that the tank can be properly placed in the into the pit, and it is beneficial to the bonding operation.
2. When digging a pit, there are stones, cavities or landslides at the bottom, which should be handled or filled in time to avoid the tank being broken or cracked by stones after heavy charging.
When digging a hole, you must cut off a few roots, and paint some expensive diesel oil or lime on the incision to stop it from growing or even rotting, so as to prevent the growth of roots from damaging the pool body.
4. After digging a hole, check the size with a tape measure and trim it to the required standard.
(3) Assembly
1. Before installation, glue the water inlet and outlet to the corresponding opening position of the upper half pool.
2. Before installation, carefully check whether the biogas digester is damaged, and repair it in time if there is any damage.
3, before putting the pool, check whether the bottom is flat, and put a layer of fine loose soil, can not have water, stones and other hard objects.
4. When placing the pond, place the upper hemisphere in into the pit according to the marked direction, flatten it and backfill it. After tamping the lower half along the bottom, fasten the upper hemisphere to the lower hemisphere according to the marked direction.
5. When entering the pool, clean up the sundries and sludge at the junction of the upper and lower pools, polish the new crop with sandpaper, and fill up the junction of the upper and lower pools with glass fiber reinforced plastic putty. Outside the pool, the joint between the upper and lower pools outside the pool body will be drilled with glass fiber reinforced plastic putty, which can be filled after it is cured.
6. Drill a hole in the movable cover or pool top, stick on the air outlet pipe, install the switch, and you can cut the door.
7, the use of glass fiber reinforced plastic flange cover. After the raw materials, inoculum and water are added, the flange of glass fiber reinforced plastic (FRP) is wiped clean, and then the gasket-free sealant is squeezed on the plane of the inner edge of the flange and left to air for about one hour. When the sealant solidifies into an elastic apron, cover the FRP cover plate on the flange (the screw hole of the cover plate should be aligned with the screw hole of the flange), screw on eight screws with the diameter of 10MM×50MM, and seal the pool.
8. Use concrete movable cover. After feeding, inoculating and water, clay and lime powder with high viscosity are selected. First, dry clay without sand is hammered, coarse particles and sundries are screened out, and dry mixed with lime powder according to the ratio of 3-5:1,and then mixed with backwater to knead into dough. Before sealing, use a broom to clean the mud and sand impurities stuck on the water storage ring, the bottom of the movable cover and the surrounding edges, then rinse them with water, spread the kneaded lime mortar evenly on the movable cover, and then sit the movable cover on the mortar. Pay attention to the uniform gap between the movable cover and the water storage ring, and tighten it with your feet to make it closely combined. After sealing the movable cover with lime cement, tighten the reverse bolt, turn on the biogas switch, pour water into the water storage ring, keep it for 1~2 days, and turn off the switch for later use. It is best to keep the top cover from dehydration for a long time.
9. Stick the gas pipeline to the partition door, install the water controller and desulfurizer, introduce the pipeline indoors, and connect the biogas appliances such as stoves and lamps.
(4) Pressure test
After the installation of biogas digesters and biogas appliances is completed, close all shut-off doors, inject water into the pool for pressure test until the water surface rises to the edge of the inlet and outlet, and then wipe the joint between the pool body and the pipeline with a soap brush to observe whether there are bubbles. If there are bubbles, it means that there is air leakage here, so it should be sealed in time.
(5) Backfill soil
1. After the tank is sealed with the pipeline, backfill the gap with fine loose soil or sand, water it while filling, and then tamp it with a wooden stick. Be careful not to puncture the pool wall or water it too much to avoid the biogas digester floating up.
2. In areas with high groundwater level, water should be added to the pool to half the volume at the same time before water injection. When backfilling rammed earth, don't hit the biogas digester with wooden sticks or other tools to avoid damaging the biogas digester.
3. After the backfill is padded to the upper edge of the water inlet and outlet and the height of the flange ring, the wall with the radian of the water inlet and outlet is bricked, and the ground is leveled. The water outlet leaking out of the ground and the flange retaining wall should be covered with wooden covers to prevent people and animals from falling into it.
4. After the backfill soil is compacted, assemble the ground pool shed, straighten out the gas pipeline, adjust the cooker, and close all the cutting doors for standby after gas production.
(6) Fire resistance test
When the barometer shows the air pressure, you can deflate and test the fire. At the initial stage of biogas fermentation, the gas produced is mainly carbon dioxide produced by acidification. When the pool is closed, there is still a lot of air in the gas box, so the methane content in the gas is low and usually non-combustible. Therefore, when the small water column of the biogas pressure gauge reaches more than 3kpa, the gas of 1~2 times should be released first, and ignition can only be started when the methane content in the gas in the pool reaches more than 30%.
Third, the starting method
1, prepare enough raw materials. (1) Raw material consumption: an 8M3 biogas digester with a charging rate of 85% and a feed liquid concentration of 4-6% needs 2.9M3~4.4M3 of fresh pig manure or 2.27M3~3.4M3 of fresh cow dung. (2) Raw materials: First, bring your own raw materials and use your own pig dung; The second is to pull livestock manure from pig farms or cattle farms. Before pulling feces, be sure to know whether it has been disinfected recently (just disinfected feces cannot be used). It is best to use cow and horse manure in the first pool.
2. pile up raw materials. Spread a layer of plastic film on the ground, mix the fertilizer with the inoculum, and sprinkle water in layers. The amount of water added is wet animal manure, the bottom does not run, and the water content is about 30%-40%. Then, the cow, horse manure or pig manure are fully and evenly stirred until they are collected into balls and dispersed when they enter the bottom, and then sealed with plastic film, and concentrated composting is carried out, with a pile height of 0.6- 1 m.. Generally, the composting time is 5 ~ 7 days in summer and 7 ~ 10 days in spring and autumn. When the compost temperature rises to 45-50℃, it should be turned over in time to prevent the fermentation raw materials from carbonization due to excessive temperature during composting.
3. Add enough inoculum. Due to the different sources and types of fermentation raw materials, the number of methanogenic bacteria in fermentation raw materials varies greatly. Therefore, adding enough inoculum is one of the important conditions to ensure rapid biogas production. The inoculation amount of the new tank is 10 ~ 20% of the total feed liquid.
4. Add water to the raw materials. An 8M3 biogas digester needs 3.9~2.4M3 water for fresh pig manure and 4.5~3.4M3 water for fresh cow manure. The water to be added to the biogas digester is preferably warm water exposed to sunlight. It is not convenient to directly use tap water or extract well water to join the biogas digester (because the temperature of well water is low and the biogas digester starts slowly). If tap water or well water is to be used, it should be heated by the sun before entering the pool.
5, raw materials into the pool. Feeding should be carried out at 1- 3 pm, and feeding should be fast and short. When feeding, water should be added, and the self-made wooden pestle should be repeatedly stirred up and down to make the feed liquid in the pool mix evenly. The liquid level is about 75 cm from the skylight.
6. Don't start in winter. Biogas digesters are generally not started in winter. When the temperature is too low in winter, it is difficult for new materials to produce methanogens, which may easily lead to long-term non-gas production, and it may be necessary to completely change materials in spring.
Fourth, the method of use
To make good use of biogas digesters, we must first understand the generation principle of biogas and master the conditions for making biogas. Biogas is a kind of combustible gas produced by organic matter under certain temperature, humidity, pH and other conditions under the action of biogas-passing bacteria. Biogas is a mixed gas, its main component is methane (CH4), and the rest are carbon dioxide (CO2), oxygen (O2), nitrogen (N2) and hydrogen sulfide (H2S). The methane content is about 55%-70%, and the carbon dioxide content is about 30%-45%. Methane is a colorless and odorless gas with molecular formula of CH4 and molecular weight of 16.04. Under the standard conditions of 0℃, 10 1325Pa, the relative density of methane and air is 0.5548, and the relative density of biogas is about 0.94. The calorific value of methane is 35.9MJ/m3, and the low calorific value of biogas is 20-25MJ/m3.
There are seven conditions for biogas production:
1, strictly oxygen-free environment. Biogas fermentation microorganisms include acidogenic bacteria and methanogenic bacteria, both of which are anaerobic bacteria, especially methanogenic bacteria are particularly sensitive to oxygen. They can't live in an aerobic environment, and even a small amount of oxygen will hinder fermentation. Therefore, it is the key to produce biogas artificially to have an airtight biogas digester.
2. Sufficient and excellent inoculum. Inoculant is anaerobic activated sludge containing a large number of microorganisms, also known as strains. Only with enough excellent inoculum can biogas fermentation run efficiently. Inoculants in rural household biogas digesters generally come from biogas residues (biogas slurry), sewage sludge and sediments at the bottom of septic tanks. The inoculation amount generally accounts for about 30% of the total fermentation broth.
3. Necessary fermentation temperature. Biogas fermentation strains can ferment and produce gas in the range of 8℃~60℃. The higher the temperature, the more active the fermentation and the more gas produced. Therefore, as a rural household biogas digester with normal temperature fermentation, the fermentation temperature should be kept above 8℃ as far as possible.
4. Suitable pH value. In the process of biogas fermentation, biogas bacteria are suitable for breeding in neutral or microenvironment, and the PH value of fermentation broth should be controlled at 6.8~7.5. If it is lower or higher than this value, biogas fermentation will be very slow, or even unable to proceed normally.
5. Appropriate fermentation concentration and hydrocarbon ratio. Organic matter such as crop straw, pasture, human and animal manure and domestic sewage can be used as raw materials for biogas fermentation. However, the ratio of carbon to nitrogen should be (20 ~ 30): 1, and the fermentation concentration should be 6%~ 10%. Of course, the ratio of carbon to nitrogen and fermentation concentration can be lower in summer and higher in winter.
6. Stir regularly. When the biogas digester is not stirred, the fermentation broth is obviously divided into three layers: the upper hard shell layer, the middle clear liquid layer and the lower precipitation layer. The stratification of fermentation broth is not conducive to gas production, so stirring measures should be considered. The purpose of stirring is to make it not delaminate, make raw materials and inoculum evenly distributed in the pool, increase the contact surface between microorganisms and raw materials, speed up fermentation and improve gas production rate. In addition, stirring is also beneficial to the release of biogas. For biogas digesters with heating devices, stirring is beneficial to the diffusion of heat energy. At present, there are three main stirring methods: mechanical stirring, liquid stirring and gas stirring.
7. Beware of adding inhibitors. Inhibitors are mainly some heavy metal ions, pesticides and some toxic substances. This substance cannot be added to the biogas digester.
Five, the daily management of biogas digesters
"Three points to build a pool, seven points to manage things." After the biogas digester is completed, whether it can run normally and make its own biogas digester produce good gas and vigorous gas depends on its scientific daily management.
(A) to often import and export materials
In order to ensure that biogas bacteria have enough food and normal metabolism, so that gas production is normal and lasting, it is necessary to constantly supplement fresh fermentation raw materials and replace some old raw materials, so as to achieve regular feeding and discharging.
1. According to the characteristics of fermentation raw materials in rural household biogas digesters, it is generally appropriate to feed and discharge 5% every 5- 10 days. It can also be calculated according to the amount of dry biogas input of 3-4 kg per cubic meter. For the "four-in-one" tank, human and animal feces and urine are continuously and automatically injected into the tank every day, so the feed concentration can be adjusted appropriately according to the situation.
2. Problems needing attention in normal feeding and discharging:
In principle, how much is in, and the order is first out and then in;
When discharging, the liquid level of the remaining feed liquid should not be lower than the upper edge of the feed inlet of the tank, so as to avoid the methane in the tank escaping from the feed inlet of the tank;
After unloading, new materials should be added in time. If the raw materials for primary fermentation are insufficient, more water can be added to maintain the original water level, so that the biogas in the pool has a certain pressure.
3. Problems that should be paid attention to in large refueling: In order to meet the needs of biogas bacteria metabolism and fertilizer use in farmland seasons, the time for large refueling is generally arranged in spring and autumn.
Feeding should be stopped 20-30 days before the fuel is changed to avoid wasting fermentation raw materials.
New materials should be added in time after large displacement, so that the biogas digester can produce gas again and put into use as soon as possible.
When discharging, all residues and part of feed liquid in the biogas digester should be removed, and 10%-30% feed liquid mainly containing activated sludge should be left as inoculum to speed up the start-up of the biogas digester and achieve the purpose of rapid gas production.
Keep stirring.
Frequent stirring is an important measure to improve gas production rate. If it is not stirred frequently, the scum layer in the pool will form a thick hard shell, which will prevent the biogas generated in the lower layer from entering the gas box and reduce the gas production. Rural household biogas digesters are generally not equipped with stirring devices, and the following two methods can be adopted: 1, stirring from the import and export; 2. Take out several barrels of fermentation liquid from the discharge chamber, and then flush the fermentation liquid into the tank from the inlet, which can also play the role of stirring the fermentation raw materials in the tank.
Frequently measure and adjust the PH value of fermentation broth.
Biogas bacteria are suitable for growth and reproduction in neutral or slightly alkaline environment (PH6.8-7.6). Excessive PH (pH less than 6.5 or greater than 8) is not conducive to the activities of biogas bacteria and reduces the gas production rate. In order to accelerate gas production, the following adjustment measures can be taken: 1, adding appropriate amount of plant ash; 2. Take out part of the fermentation raw materials, and supplement the same or slightly more nitrogen-containing fermentation raw materials and water; 4. Mix human and animal excrement into plant ash, and add them into biogas digester; 4. Add a proper amount of lime water, but not lime, but a clear solution of lime water. At the same time, the clarified liquid added into the tank should be mixed evenly with the fermentation liquid to avoid strong alkali from damaging the bacterial activity of biogas.
In addition, in order to ensure that biogas fermentation will not be destroyed, it is necessary to prohibit the addition of various large-dose fermentation inhibitors, especially highly toxic pesticides and various powerful fungicides. The biogas digesters damaged by this reason need to be cleaned before they can be put into operation again.
(2) Adjust the water quantity regularly.
Too much or too little water in biogas is not conducive to the reproduction of biogas bacteria and the production of biogas. When the water content is too high, the dry matter content in the fermentation broth is less and the gas production per unit volume is less; If the water content is too small and the fermentation broth is too thick, the upper organic acid fermentation raw materials are easy to form a hard shell, which hinders biogas fermentation and affects gas production.
Safety management and safe gas use
1, the entrance and exit of biogas digester should be covered to avoid children and livestock falling in, causing casualties. It also helps to keep warm.
2. Be sure to observe the pressure gauge. When the pressure in the tank is too high, it will not only affect the gas production, but even flush the tank cover. If the pool cover is washed away, put out the nearby fireworks immediately to avoid fire. The pressure of biogas digester should be controlled at about 8kpa. When feeding and discharging, always pay attention to the changes on the pressure gauge. When feeding, if the pressure is too high and the air pressure is higher than 12kpa, the airway should be opened to deflate and the feeding speed should be slowed down. When discharging, if there is negative pressure on the pressure gauge, the gas should be temporarily stopped until it returns to normal.
3, it is strictly prohibited in the biogas digester, discharge or airway mouth ignition, so as not to cause tempering, leading to severe expansion, explosion and rupture of gas in the pool, causing fire.
4. It is forbidden to add linoleum, bone meal, cottonseed cake and phosphate rock powder in the biogas digester to prevent the production of a highly toxic gas-dihydrogen phosphide, which is seriously harmful to human body.
5. Don't put biogas lamps and stoves near flammable materials such as clothes and firewood, and pay attention to safety when igniting or burning. Always check whether the gas transmission system is leaking and unblocked. If air leakage is found, measures should be taken in time to make the air circulate and fully ventilate before ignition. If the airway is blocked, it must be cleaned immediately.
Six, the winter management of biogas digesters
In our north, it is colder in winter. Although the insulation layer is added in the production process of FRP ellipsoidal insulation biogas digesters, it is very important to strengthen management in winter because of the diversity of fermentation raw materials in rural biogas digesters. Temperature is the key factor affecting the fermentation speed of biogas, and the essence of its influence is the activity of enzyme. In a certain range, the higher the temperature, the better the flow activity of the enzyme and the faster the gas production rate. For buried biogas digesters, the fermentation temperature of biogas is affected by ground temperature, which is also affected by air temperature. Therefore, we should take artificial measures to raise the ground temperature and keep it as constant as possible. To improve biogas production in winter, simply put, it is to let biogas digesters "eat their stomachs and cover their quilts". This is because the pool temperature drops rapidly from the beginning of cold dew, so it is necessary to take heat preservation measures and do the following work well:
1, pipeline maintenance. Check whether there is water in the pipeline before winter, and bury or wrap the pipeline as much as possible to prevent freezing and cracking.
2. Choose sunny days for discharging and feeding at noon.
3. Improve the concentration of fermentation broth and the temperature of the pool. Increase the concentration of 6% feed liquid to about 10% before winter. In winter, timely feeding is needed to increase the concentration to about 15%-20%, so that the biogas digester can operate at high concentration.
4. In early winter, the temperature difference between day and night is large, so special attention should be paid to the insulation of biogas digesters at night. Cover the shed with shed formwork as soon as possible. As the temperature drops, cover it with thermal insulation materials such as straw curtains before sunset.
5. Keep frequent feeding and discharging. Supplementing fresh raw materials, extracting fermented old materials, providing sufficient nutrition for microorganisms and improving gas production.
6. Stir frequently. Every 3-4 days, it can be pumped for about 20 times by a slag catcher or more than ten barrels of biogas slurry can be taken out from the discharge port and poured into the feed port, so that the feed liquid in the fermentation chamber can be stirred.
7, heat preservation method should be flexible and diverse. There are mainly the following types: 1. The surface of biogas digester is covered with firewood to keep warm. Covering materials include straw, grass, pond compost or thickened soil layer. , and the coverage area is larger than the pool surface, which is convenient for heat preservation. 2. Dig an annular trench for insulation. Dig an annular ditch around the biogas digester, pile dung and grass in the ditch, and keep warm by fermentation heat. 3, plastic shed insulation. Build a plastic shed on the pool surface and make full use of solar energy to keep warm.
8. Buy the wind heating induction device and solar heat flow replacement device developed by our company to heat the biogas digester.
The use value of biogas digesters.
Biogas can be used by farmers for boiling water, cooking, lighting, heating, keeping fruits and vegetables fresh and storing grains; Biogas slurry can be used as liquid fertilizer to control pests and diseases, and can also be used as feed additive for pigs, cattle, chickens and fish. Biogas residue can be used to prepare nutrient soil, make organic fertilizer, cultivate mushrooms, ganoderma lucidum and cultivate earthworms. It can be said that biogas, biogas slurry and biogas residue produced by biogas digesters are valuable and can be comprehensively utilized.
According to some data, a new concrete biogas digester with 8~ 10 cubic meter can produce 380~450 cubic meters of biogas every year, which can solve the domestic fuel for 3~5 people 10~ 12 months, saving 2000 kilograms of coal and about 200 degrees of electricity. Biogas fertilizer is provided throughout the year, equivalent to 50 kg of ammonium sulfate, 40 kg of calcium superphosphate and 0/5 kg of potassium chloride/kloc. The application of biogas fertilizer can increase the yield of all food crops, cash crops and fruit trees by 5%~20%. Soaking seeds with biogas slurry can improve the germination rate and seedling rate of seeds and enhance the disease resistance and stress resistance of seedlings. When biogas slurry is used as feed additive, it can be released 20~30 days in advance; Feeding yellow cattle, the average daily milk yield increased by 2.29~2.4 kg; When feeding chickens, the laying rate of hens increased by 25%, and the weight gain rate of broilers increased by 28.75%. Raising fish can increase production by 10%. Mushroom cultivation with biogas residue can increase production by 20%~30%. Applying carbon dioxide gas fertilizer to vegetables in biogas lamp greenhouse can increase the yield of cucumber by 30%, celery by 25% and tomato by 20%. In addition, the humic acid content in biogas manure is 10~20%, which has a direct effect on the formation of soil aggregate structure. In the soil with long-term application of biogas fertilizer, the contents of nutrients such as organic matter, nitrogen, phosphorus and potassium increased obviously, soil enzyme activity increased, soil physical properties improved, and soil fertility improved significantly, which could promote sustainable agricultural production increase. In recent years, some farmers have successfully created the comprehensive utilization experience of "four in one", "three in one", "five supporting facilities" and "pig-biogas-fruit" by using biogas digesters, and received good economic benefits. The "four-in-one" ecological greenhouse model in northern rural areas summarized by rural energy science and technology workers in Liaoning Province combines biogas digesters, pig poultry houses, toilets and solar greenhouses into a biogas comprehensive utilization system, and the annual economic income of each system is as high as 4,000 ~ 8,000 yuan. In a word, building a new efficient biogas digester is equivalent to a household clean energy manufacturing center, a small farm, an organic fertilizer production workshop, a courtyard fertilizer purifier and a cash cow. It can not only produce cooking and lighting fuel, but also produce high-quality and efficient organic fertilizer, and can also treat yard pollutants and change the "dirty, chaotic and poor" sanitary appearance. Through the comprehensive utilization of "Three Marshes", the output and quality of agricultural products can be improved, farmers' income can be increased, farmers can get rid of poverty and become rich, and the process of rural modernization can be promoted.
Jinshi FRP biogas digester Liaoning general agency
Main technical parameters of products
Product specifications are 8 cubic meters and 10 cubic meters. It consists of an upper hemisphere, a lower hemisphere, an inlet, an outlet (hydraulic chamber) and a movable cover. Split transportation, family assembly and underground use. The main technical parameters are as follows:
The basic parameter unit is 8 m3 10 m3.
Diameter m 2.4 0.03 2.6 0.03
Weight kg 200 5 235 5
Wall thickness mm 6 1 6 1
Tensile strength MPa 4.7 0.54.7 0.5
Bending strength MPa 6.6 1 1
Bus hardness 60 5 60 5
The water absorption is 0.4 0. 1.4 0. 1.
The seal is saturated with water, and there is no leakage for 24 hours. The inflation pressure is 8Kpa, and there is no depressurization for 24 hours.
Total water deformation without deformation
After being placed in acid-resistant PH5 solution for 72 hours, the pattern does not soften, bubble, crack or dissolve.
After being placed in alkali-resistant PH8 solution for 72 hours, the pattern does not soften, bubble, crack or dissolve.
The temperature is 80℃, and the pattern is not softened, blistered, cracked or dissolved after 24 hours of water bath.
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