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(xì)菌發(fā)酵分解有機(jī)物質(zhì)產(chǎn)生的，豐富的有機(jī)物質(zhì)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(duì)沼氣的產(chǎn)生過(guò)程進(jìn)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，必須創(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(yán)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(jī)物質(zhì)產(chǎn)生沼氣的細(xì)菌是產(chǎn)甲烷菌，都是厭氧性細(xì)菌，對(duì)氧特別敏感，它們?cè)谏L(zhǎng)、發(fā)育、繁殖、代謝等生命活動(dòng)中都不需要空氣，空氣中的氧氣會(huì)使其生命活動(dòng)受到抑制，甚至死亡。產(chǎn)甲烷菌只能在嚴(yán)格厭氧的環(huán)境中才能生長(zhǎng)。所以，修建沼氣池，要嚴(yán)格密閉，不漏水，不漏氣，這是制取沼氣的關(guān)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(chǎn)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(zhì)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(chǎn)生沼氣的物質(zhì)基礎(chǔ)，又是沼氣細(xì)菌賴以生存的營(yíng)養(yǎng)來(lái)源，各種有機(jī)物質(zhì)如人畜糞便、作物秸稈、樹(shù)葉雜草、生活污水、含有機(jī)物質(zhì)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(shù)，沼氣設(shè)備但細(xì)菌對(duì)營(yíng)養(yǎng)物質(zhì)中的碳素、氮素需要量必須維持適當(dāng)?shù)谋壤禾嫉壤涑?5：1-30：1。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(jīng)過(guò)人和動(dòng)物腸胃系統(tǒng)的充分消化，一般顆粒細(xì)小，含水量較高，容易厭氧分解，產(chǎn)氣快，發(fā)酵期短。秸桿。稻草、菜蔓、枇殼等農(nóng)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(zhì)素和植物蠟質(zhì)，稱“富碳原料”。干物質(zhì)含量比富氮原料高，發(fā)酵前一般需經(jīng)物理、化學(xué)、生物三步預(yù)處理。富碳原料其厭氧分解比富氮原料慢，產(chǎn)期周期長(zhǎng)，產(chǎn)氣量高。氮素是構(gòu)成微生物細(xì)胞質(zhì)的重要原料，碳素不僅構(gòu)成微生物細(xì)胞質(zhì)，而且提供生命活動(dòng)的能量。發(fā)酵原料的碳氮比不同，因發(fā)酵細(xì)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(jìn)行。如果比例失調(diào)，就會(huì)使產(chǎn)氣和微生物的生命活動(dòng)受到影響。因此，制取沼氣不僅要有充足的原料，還應(yīng)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(nèi)因條件，一切外因條件都是通過(guò)個(gè)基本的內(nèi)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(zhǎng)，則遲遲不產(chǎn)氣或產(chǎn)氣少。采用預(yù)先漚制過(guò)的原料，并加入少量沼氣污泥進(jìn)行發(fā)酵，甲烷含量很快上升。說(shuō)明厭氧發(fā)酵必須有大量菌種。

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(shí)溫度的高低直接影響原料的消化速度和產(chǎn)氣率，溫度適宜則細(xì)菌繁殖旺盛，活力強(qiáng)，厭氧分解和生成甲烷的速度就快，產(chǎn)氣就多。適宜沼氣發(fā)酵的溫度范圍較廣，一般8～70℃，都能產(chǎn)生沼氣。低于10℃或者高于60℃，都嚴(yán)重抑制微生物生存、繁殖、影響產(chǎn)氣。根據(jù)實(shí)際情況，人們把沼氣發(fā)酵劃分三個(gè)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(nóng)戶通常采用的是常溫發(fā)酵工藝。在這一溫度范圍內(nèi)，一般溫度愈高，微生物活動(dòng)愈旺盛，產(chǎn)氣量愈高。微生物對(duì)溫度變化十分敏感，溫度突升或突降，都會(huì)影響微生物的生命活動(dòng)，使產(chǎn)氣狀況惡化。這就是為什么沼氣池在夏季，特別是氣溫最高的7月產(chǎn)氣量大，而在冬季最冷的1月產(chǎn)氣很少，甚至不產(chǎn)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(zhǎng)、繁殖，要求發(fā)酵原料的酸堿度保持中性，或者微偏堿性，過(guò)酸、過(guò)堿都會(huì)影產(chǎn)氣。測(cè)定表明，酸堿度在pH=6-8之間，均可產(chǎn)氣，以pH=6．5-7．5產(chǎn)氣量最高，pH低于6或高于9時(shí)均不產(chǎn)氣。在正常的發(fā)酵過(guò)程中，沼氣池內(nèi)的酸堿度變化可以自然進(jìn)行調(diào)解，先由高到底，然后又升高，最后達(dá)到恒定的自然平衡（即適宜的pH），一般不需要進(jìn)行人為調(diào)節(jié)。只有在配料和管理不當(dāng)，使正常發(fā)酵過(guò)程受到破壞的情況下，才可能出現(xiàn)有機(jī)酸大量積累，發(fā)酵料液過(guò)于偏酸的現(xiàn)象。此時(shí)，可取出部分料液，加入等量的接種物，將積累的有機(jī)酸轉(zhuǎn)化為甲烷，或者添加適量的草木灰或石灰澄清液，中和有機(jī)酸，使酸堿度恢復(fù)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(yán)格控制阻抑物含量

5、 Strictly control the content of inhibitory substances

沼氣細(xì)菌很容易受到阻抑物的影響，抑制沼氣細(xì)菌的生命活動(dòng)，防礙產(chǎn)氣。沼氣池內(nèi)揮發(fā)酸濃度或氨態(tài)氮濃度過(guò)高，對(duì)發(fā)酵菌有抑制和阻抑作用。因此不能投入農(nóng)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(dāng)?shù)臄嚢璺绞胶蛷?qiáng)度，可以使發(fā)酵原料分布均勻，增強(qiáng)微生物與原料的接觸，防止浮渣增厚和結(jié)殼，提高原料的利用率及能量轉(zhuǎn)換效率，并有利于氣泡的釋放，使之獲取營(yíng)養(yǎng)物質(zhì)的機(jī)會(huì)增加，活性增強(qiáng)，生長(zhǎng)繁殖旺盛，從而提高產(chǎn)氣量。采用攪拌后，平均產(chǎn)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%.