Thread Content
1. In terms of gas consumption, in rural areas, an average daily gas usage per person is generally considered to be 0.3–0.4 cubic meters. For a family of four, 1.2–1.6 cubic meters of biogas are needed on average per day for cooking and lighting. If high-quality biogas lamps and stoves are used, the gas consumption can be further reduced. Generally, a conventional biogas digester can produce 0.2 to 0.3 cubic meters of biogas per day per cubic meter. For a family of four, a biogas digester with a capacity of 6 cubic meters is required. Commercial fiberglass biogas digesters have a higher gas production rate, producing around 0.4 cubic meters of biogas per day per cubic meter; therefore, a family of four only needs a biogas digester with a capacity of 4 cubic meters. 2. Calculated from the perspective of the raw materials used for biogas fermentation, since livestock manure is currently the main material for this process, it is generally required that the manure from each pig weighing over 50 kilograms be used in an amount of 5–15 kilograms for fermentation purposes. Therefore, a conventional biogas digester with a capacity of 1 cubic meter, or a fiberglass biogas digester with a capacity of 0.6 cubic meters, is needed. When planning the size of a biogas digester, the number of livestock kept can be used as a key basis for calculation: generally, families with 2–3 medium-sized pigs (50 kilograms each, the same unit applies here) should consider constructing a biogas digester with a capacity of 4 cubic meters. However, users should consider the issue of insufficient pool capacity if the number of poultry and livestock increases in the future, and may want to consider building a larger pool. A stock of 4–6 medium-sized pigs makes it appropriate to build a 6 m3 biogas digester. A stock of 8–10 medium-sized pigs requires a storage capacity of 8 m3. For a herd size of over 10 medium-sized pigs, it is advisable to increase the pool volume by 1 m3 for every additional medium-sized pig in the herd. In other words, for 15 pigs, a tank of 15 m3 is sufficient; if there is not enough raw material for fermentation, building a larger tank results in a lower gas production rate compared to using a smaller tank. On the other hand, if there is an abundance of raw material but the tank is too small, it can lead to overloading issues. (The amount of feces produced by one large cow is roughly equivalent to that produced by 10 medium-sized pigs.) The feces output of 100 chickens is roughly equivalent to that of one medium-sized pig. ) 3. The pool capacity can also be planned based on local conditions such as temperature. In the southern regions, conventional household biogas digesters with a capacity of over 6 cubic meters or fiberglass household biogas digesters with a capacity of 4 cubic meters can be used. Biogas digesters built according to this standard, when properly maintained, can produce enough biogas during spring, summer, and autumn to meet the energy needs for cooking, boiling water, lighting, and other daily activities; there is usually even a surplus. In winter, as temperatures drop, the amount of biogas produced decreases, but it is still sufficient to meet the needs for cooking. In warmer regions in the south, fiberglass biogas digesters can generally still meet the energy requirements for cooking, stir-frying, boiling water, and other daily tasks. Some people believe that \"the larger the biogas digester, the more gas it will produce,\" but this view is incorrect. Whether there is gas or not depends on \"construction\" (building the pool), while the amount of gas produced depends on \"management\". Even though biogas digesters have a large volume, if there is insufficient fermentation material and poor management, their gas production will be lower than that of smaller digesters. However, biogas digesters cannot be made too small, as a too small volume makes it difficult to ensure an adequate amount of gas production, which affects the normal use by farmers. Generally, conventional biogas digesters should have a volume of at least 6 cubic meters. Since fiberglass biogas digesters have a higher gas production rate, a digester with a volume of 4 cubic meters is sufficient to meet the daily energy needs of ordinary farmers.