沼氣發(fā)電中沼氣發(fā)酵的基本條件：沼氣是多種厭氧性細菌發(fā)酵分解有機物質產生的，豐富的有機物質在隔絕空氣和保持一定水分、溫度的條件下，便能生成沼氣。于是人們對沼氣的產生過程進行了深入研究，逐步弄清了人工制取沼氣的工藝條件。人工制取沼氣，建議創(chuàng)造厭氧發(fā)酵的基本條件，若不具備相用的條件將得不到沼氣或得到很少。這些基本條件是：

The basic conditions for biogas fermentation in biogas power generation: Biogas is produced by the fermentation and decomposition of organic matter by various anaerobic bacteria. Rich organic matter can generate biogas under the conditions of isolating air and maintaining certain moisture and temperature. So people conducted in-depth research on the production process of biogas and gradually clarified the process conditions for artificially producing biogas. To artificially produce biogas, it is necessary to create the basic conditions for anaerobic fermentation. Without the necessary conditions, biogas cannot be obtained or very little can be obtained. These basic conditions are:

一、嚴格的厭氧環(huán)境一密封的厭氧發(fā)酵池

1、 Strict anaerobic environment - a sealed anaerobic fermentation tank

分解有機物質產生沼氣的細菌是產甲烷菌，都是厭氧性細菌，對氧非常敏感，它們在生長、發(fā)育、繁殖、代謝等生命活動中都不需要空氣，空氣中的氧氣會使其生命活動受到抑制，甚至死亡。產甲烷菌只能在嚴格厭氧的環(huán)境中才能生長。所以，修建沼氣池，要嚴格密閉，不漏水，不漏氣，這是制取沼氣的關鍵。這不僅是收集沼氣和貯存沼氣發(fā)酵原料的需要，也是保證沼氣微生物在厭氧的生態(tài)條件下生活得好，使沼氣池能正常產氣的需要。

The bacteria that decompose organic matter to produce biogas are methanogens, which are anaerobic bacteria that are particularly sensitive to oxygen. They do not require air for their growth, development, reproduction, metabolism, and other life activities. The oxygen in the air can inhibit their life activities and even cause death. Methanogenic bacteria can only grow in strictly anaerobic environments. So, when building a biogas digester, it must be strictly sealed, leak free, and leak free, which is the key to producing biogas. This is not only necessary for collecting biogas and storing biogas fermentation materials, but also for ensuring that biogas microorganisms live well under anaerobic ecological conditions, so that biogas digesters can produce gas normally.

二、適宜的發(fā)酵原料和質優(yōu)量足的菌種

2、 Suitable fermentation materials and high-quality and abundant bacterial strains

沼氣發(fā)酵原料是產生沼氣的物質基礎，又是沼氣細菌賴以生存的營養(yǎng)來源，各種有機物質如人畜糞便、作物秸稈、樹葉雜草、生活污水、含有機物質的工業(yè)廢渣等，都可以作為沼氣池發(fā)酵的原料。沼氣技術，沼氣設備但細菌對營養(yǎng)物質中的碳素、氮素需要量建議維持適當的比例：碳氮比例配成25：1-30：1。人畜糞便和作物秸稈是主要的發(fā)酵原料。人畜和家禽糞便富含氮元素，稱“富氮原料”。這類原料經過人和動物腸胃系統的充分消化，一般顆粒細小，含水量較高，容易厭氧分解，產氣快，發(fā)酵期短。秸桿。稻草、菜蔓、枇殼等農作物的殘余物，這些原料富含纖維素、半纖維素、果膠以及難降解的木質素和植物蠟質，稱“富碳原料”。干物質含量比富氮原料高，發(fā)酵前一般需經物理、化學、生物三步預處理。富碳原料其厭氧分解比富氮原料慢，產期周期長，產氣量高。氮素是構成微生物細胞質的重要原料，碳素不僅構成微生物細胞質，而且提供生命活動的能量。發(fā)酵原料的碳氮比不同，因發(fā)酵細菌消耗碳的速度比消耗氮的速度要快25～30倍?？梢允拐託獍l(fā)酵在合適的速度下進行。如果比例失調，就會使產氣和微生物的生命活動受到影響。因此，制取沼氣不僅要有充足的原料，還應注意各種發(fā)酵原料碳氮比的合理搭配。

The raw materials for biogas fermentation are the material basis for producing biogas, as well as the nutritional source for biogas bacteria to survive. Various organic substances such as human and animal manure, crop straw, leaves and weeds, domestic sewage, and industrial waste containing organic substances can all be used as raw materials for biogas digester fermentation. Biogas technology and equipment require bacteria to maintain an appropriate ratio of carbon and nitrogen in nutrients: the carbon to nitrogen ratio should be set at 25:1-30:1. Human and animal manure and crop straw are the main fermentation materials. Human, livestock, and poultry manure are rich in nitrogen elements, known as "nitrogen rich raw materials". This type of raw material is fully digested by the gastrointestinal system of humans and animals, with generally small particles, high water content, easy anaerobic decomposition, fast gas production, and short fermentation period. Straw. The residues of crops such as straw, vines, and shells are rich in cellulose, hemicellulose, pectin, as well as recalcitrant lignin and plant wax, known as "carbon rich materials". The dry matter content is higher than that of nitrogen rich raw materials, and generally requires three steps of physical, chemical, and biological pretreatment before fermentation. The anaerobic decomposition of carbon rich raw materials is slower than that of nitrogen rich raw materials, with a longer production cycle and higher gas production. Nitrogen is an important raw material for the formation of microbial cytoplasm, while carbon not only constitutes microbial cytoplasm but also provides energy for life activities. The carbon to nitrogen ratio of fermentation materials varies, as fermentation bacteria consume carbon 25-30 times faster than nitrogen. It can enable biogas fermentation to proceed at an appropriate speed. If the proportion is imbalanced, it will affect the production of gas and the life activities of microorganisms. Therefore, in order to produce biogas, it is not only necessary to have sufficient raw materials, but also to pay attention to the reasonable combination of carbon and nitrogen ratios of various fermentation materials.

沼氣發(fā)酵微生物是人工制取沼氣和內因條件，一切外因條件都是通過個基本的內因條件才能起作用。因此，沼氣發(fā)酵的前提條件就是要接入含有大量這種微生物的接種物。新鮮原料入池發(fā)酵，若加入的菌種很少，厭氧發(fā)酵停滯期很長，則遲遲不產氣或產氣少。采用預先漚制過的原料，并加入少量沼氣污泥進行發(fā)酵，甲烷含量很快上升。說明厭氧發(fā)酵建議有大量菌種。

Biogas fermentation microorganisms are the artificial production of biogas and internal conditions, and all external conditions can only work through a basic internal condition. Therefore, the prerequisite for biogas fermentation is to introduce inoculants containing a large amount of these microorganisms. Fresh raw materials are fermented in the pool. If there are few added bacterial strains and the anaerobic fermentation has a long stagnation period, it will result in delayed or insufficient gas production. Using pre fermented raw materials and adding a small amount of biogas sludge for fermentation, the methane content quickly increases. Anaerobic fermentation requires a large number of bacterial strains.

三、沼氣發(fā)酵的重要外因條件一溫度、水分

3、 Important external factors for biogas fermentation: temperature and moisture

沼氣發(fā)電而發(fā)酵時溫度的高低直接影響原料的消化速度和產氣率，溫度適宜則細菌繁殖旺盛，活力強，厭氧分解和生成甲烷的速度就快，產氣就多。適宜沼氣發(fā)酵的溫度范圍較廣，一般8～70℃，大多能產生沼氣。低于10℃或者高于60℃，都嚴重抑制微生物生存、繁殖、影響產氣。根據實際情況，人們把沼氣發(fā)酵劃分三個發(fā)酵區(qū)：即10～30℃為常溫發(fā)酵區(qū)，33-38℃為中溫發(fā)酵區(qū)，50～55℃為高溫發(fā)酵區(qū)。農戶通常采用的是常溫發(fā)酵工藝。在這一溫度范圍內，一般溫度愈高，微生物活動愈旺盛，產氣量愈高。微生物對溫度變化十分敏感，溫度突升或突降，都會影響微生物的生命活動，使產氣狀況惡化。這就是為什么沼氣池在夏季，非常是氣溫非常高的7月產氣量大，而在冬季非常冷的1月產氣很少，甚至不產氣的原因。

The temperature during fermentation of biogas power generation directly affects the digestion rate and gas production rate of raw materials. If the temperature is suitable, bacteria will grow vigorously and have strong vitality. The speed of anaerobic decomposition and methane production will be faster, resulting in more gas production. The temperature range suitable for biogas fermentation is relatively wide, generally between 8-70 ℃, which can produce biogas. Temperatures below 10 ℃ or above 60 ℃ severely inhibit the survival, reproduction, and gas production of microorganisms. According to the actual situation, people divide biogas fermentation into three fermentation zones: the normal temperature fermentation zone at 10-30 ℃, the medium temperature fermentation zone at 33-38 ℃, and the high temperature fermentation zone at 50-55 ℃. Farmers usually use room temperature fermentation technology. Within this temperature range, generally the higher the temperature, the more vigorous the microbial activity and the higher the gas production. Microorganisms are highly sensitive to temperature changes, and sudden increases or decreases in temperature can affect their life activities and worsen gas production. This is why biogas digesters produce a large amount of gas in summer, especially in the hottest month of July, while producing very little or even no gas in the coldest month of January in winter.

四、適宜的酸堿度

4、 Appropriate pH level

沼氣微生物的生長、繁殖，要求發(fā)酵原料的酸堿度保持中性，或者微偏堿性，過酸、過堿都會影產氣。測定表明，酸堿度在pH=6-8之間，均可產氣，以pH=6．5-7．5產氣量非常高，pH低于6或高于9時均不產氣。在正常的發(fā)酵過程中，沼氣池內的酸堿度變化可以自然進行調解，先由高到底，然后又升高，非常后達到恒定的自然平衡（即適宜的pH），一般不需要進行人為調節(jié)。只有在配料和管理不當，使正常發(fā)酵過程受到破壞的情況下，才可能出現有機酸大量積累，發(fā)酵料液過于偏酸的現象。此時，可取出部分料液，加入等量的接種物，將積累的有機酸轉化為甲烷，或者添加適量的草木灰或石灰澄清液，中和有機酸，使酸堿度恢復正常。

The growth and reproduction of biogas microorganisms require that the acidity and alkalinity of the fermentation materials remain neutral or slightly alkaline. Excessive acidity or alkalinity can affect gas production. The measurement shows that gas can be produced within the pH range of 6-8, with the highest gas production occurring at pH 6.5-7.5. No gas is produced when the pH is below 6 or above 9. In the normal fermentation process, the pH changes in the biogas digester can be naturally regulated, starting from high to low, then rising again, and finally reaching a constant natural equilibrium (i.e. suitable pH), generally without the need for manual adjustment. Only when the ingredients and management are improper and the normal fermentation process is disrupted, can there be a large accumulation of organic acids and excessive acidity in the fermentation broth. At this point, a portion of the feed solution can be taken out and an equal amount of inoculum can be added to convert the accumulated organic acids into methane, or an appropriate amount of plant ash or lime clarification solution can be added to neutralize the organic acids and restore the pH to normal.

五、嚴格控制阻抑物含量

5、 Strictly control the content of inhibitory substances

沼氣細菌很容易受到阻抑物的影響，抑制沼氣細菌的生命活動，防礙產氣。沼氣池內揮發(fā)酸濃度或氨態(tài)氮濃度過高，對發(fā)酵菌有抑制和阻抑作用。因此不能投入農藥、油氈、電石、及含有阻抑物的廢渣、廢液、廢水等。

Biogas bacteria are easily affected by suppressants, which inhibit their life activities and hinder gas production. Excessive concentration of volatile acid or ammonia nitrogen in biogas digesters can have inhibitory and blocking effects on fermentation bacteria. Therefore, pesticides, oil felt, calcium carbide, and waste residues, liquids, and wastewater containing inhibitors cannot be used.

六、持續(xù)的攪拌

6、 Continuous stirring

適當的攪拌方式和強度，可以使發(fā)酵原料分布均勻，增強微生物與原料的接觸，防止浮渣增厚和結殼，提高原料的利用率及能量轉換效率，并有利于氣泡的釋放，使之獲取營養(yǎng)物質的機會增加，活性增強，生長繁殖旺盛，從而提高產氣量。采用攪拌后，平均產氣量可提高30％以上。

Appropriate stirring methods and intensities can evenly distribute fermentation materials, enhance the contact between microorganisms and raw materials, prevent thickening and crust formation of floating slag, improve the utilization rate and energy conversion efficiency of raw materials, and facilitate the release of bubbles, increasing their chances of obtaining nutrients, enhancing their activity, and promoting vigorous growth and reproduction, thereby increasing gas production. After mixing, the average gas production can be increased by more than 30%.