一、沼氣發電機組特性

1、 Characteristics of biogas generator sets

甲烷之所以能成為燃料是因為含有50%以上的甲烷。 一般甲烷含有60~70%的甲烷。 每立方米甲烷的低熱量約為5000~6000千卡，具有高熱值。 由于甲烷中含有二氧化碳，火焰傳播速度降低，內燃機內有良好的抗爆性能，甲烷辛烷值在105~115之間，甲烷高達135。 由于耐暴性良好，發動機可以選擇較高的壓縮比，因此只要是相同工作容積的內燃機，在使用沼氣時就能夠得到比原機更高的輸出功率。 例如，農村大量擁有的沼氣發電機組，在使用沼氣或雙燃料工作時，可以獲得與原機相當的電力。 這給輔助器具帶來便利，例如，以S195型馬力柴油機為例，它原配有兩種以上的水泵，以及拖拉機、打米、飼料粉碎、發電等工具，其輔助轉速和功率已經確定了很多年。 如果要變更的話，為沼氣發電機組新開發這么大的新產品，工作效率會提高，很難普及吧。

The reason why methane can become a fuel is because it contains more than 50% methane. Generally, methane contains 60-70% methane. The low calorific value of methane per cubic meter is about 5000-6000 kcal, with a high calorific value. Due to the presence of carbon dioxide in methane, the flame propagation speed is reduced, and the internal combustion engine has good anti knock performance. The octane number of methane is between 105 and 115, and methane can reach up to 135. Due to its good durability, the engine can choose a higher compression ratio, so as long as it is an internal combustion engine with the same working volume, it can achieve higher output power than the original engine when using biogas. For example, a large number of biogas generators in rural areas can obtain electricity equivalent to the original ones when using biogas or dual fuel for operation. This brings convenience to auxiliary equipment. For example, taking the S195 horsepower diesel engine as an example, it was originally equipped with two or more types of water pumps, as well as tools such as tractors, rice milling, feed crushing, and power generation. Its auxiliary speed and power have been determined for many years. If we want to make changes, developing such a large new product for biogas generator sets will improve work efficiency, and it is difficult to popularize it, right.

二、柴油機甲烷改造方法

2、 Methods for methane transformation in diesel engines

柴油發動機和點火型發動機(汽油發動機)是比較經濟的內燃機。 這兩種發動機在用甲烷作燃料之前須進行改造，為燃燒室提供適當的混合氣。 即在氣化器前增加甲烷-空氣混合器。

Diesel engines and ignition engines (gasoline engines) are relatively economical internal combustion engines. These two engines need to be modified before using methane as fuel to provide an appropriate mixture for the combustion chamber. Add a methane air mixer in front of the gasifier.

沼氣發動機一般分為壓縮燃燒式和點火式兩種。

Biogas engines are generally divided into two types: compression combustion and ignition.

壓縮式發動機采用柴油-沼氣雙燃料，少量柴油壓縮燃燒點燃沼氣進行燃燒功。 該發動機的特點是可以調節柴油/甲烷比，即使甲烷不足或燃氣停止，發動機也能正常工作。 缺點是系統復雜，大型沼氣發電工程往往不采用這種發動機。 其特點是多采用先導式沼氣發動機，又稱全燃式沼氣發動機，結構簡單，操作方便，無需輔助燃料，適合大中型沼氣工程作業。 將柴油發動機改造為先導沼氣發動機，除氣化器前增加沼氣―空氣混合器外，還需要增加電點火系統，同時增加火花塞。

The compression engine uses diesel biogas dual fuel, with a small amount of diesel compressed combustion igniting biogas for combustion work. The characteristic of this engine is that it can adjust the diesel/methane ratio, and even if there is insufficient methane or gas stops, the engine can still operate normally. The disadvantage is that the system is complex, and large-scale biogas power generation projects often do not use this type of engine. Its characteristic is the use of pilot type biogas engines, also known as full combustion biogas engines. It has a simple structure, convenient operation, and does not require auxiliary fuel, making it suitable for large and medium-sized biogas engineering operations. To transform a diesel engine into a pilot biogas engine, in addition to adding a biogas air mixer in front of the gasifier, it is also necessary to add an electric ignition system and spark plugs.

三、沼氣發電機組操作方法及注意事項

3、 Operating methods and precautions for biogas generator sets

使用方法：

Usage:

1、啟動：關閉沼氣閥，根據柴油機啟動方法，柴油啟動操作方法與未改造前相同。

1. Start: Close the biogas valve, and according to the diesel engine start method, the diesel start operation method is the same as before the modification.

2、啟動后操作：啟動后加載，柴油發動機油門放在合適位置(一般低于中間位置)，待發動機正常運行后，緩慢打開沼氣閥門，注入甲烷。 供給甲烷后，在調速器的作用下供油量自動減少，發動機轉速穩定。 如果沼氣供給量過多，發動機會瞬間中斷供油，發出斷斷續續的工作聲。 遇到這種情況，須隨時關閉一點，直到沼氣閥正常工作。 運行中，調整轉速的方法與改造前用柴油工作時一樣，通過改變油門把手的位置來進行。 隨著雙燃料發動機轉速和負荷大小的變化，為了確保雙燃料發動機的正常運轉和較高的油耗效果，須相應地增大或減小沼氣閥。沼氣發電機組冷卻水溫低，在小負荷下運行時，得不到低油耗效果。

2. Post start operation: After starting, load the diesel engine and place the throttle in the appropriate position (usually lower than the middle position). After the engine runs normally, slowly open the biogas valve and inject methane. After supplying methane, the fuel supply automatically decreases under the action of the governor, and the engine speed stabilizes. If the biogas supply is too high, the engine will instantly interrupt fuel supply and make intermittent working sounds. In this situation, it is necessary to close it at any time until the biogas valve is working properly. During the operation, the method of adjusting the speed is the same as that of working with diesel before the transformation, by changing the position of the throttle handle. As the speed and load of the dual fuel engine change, in order to ensure the normal operation and high fuel consumption of the dual fuel engine, it is necessary to correspondingly increase or decrease the biogas valve. The cooling water temperature of the biogas generator set is low, and it cannot achieve low fuel consumption when operating at low loads.