The principle of straw vaporization is that biomass (including straw, wood, firewood, weeds, pine needles, leaves, crop stalks, dried cattle and sheep manure, and edible fungus residue) generates energy for thermochemical reactions under high temperature and hypoxia conditions. In the transformation process, the atoms of carbon, hydrogen, oxygen and other elements in the plant matter will generate carbon monoxide, methane, hydrogen and other combustible gases under the reaction conditions according to the bonding principle of chemical bonds. The principle is relatively simple, but to achieve the purpose of gasification and from the perspective of boiler design, many requirements need to be met.
The thermochemical reaction is generally divided into the following four steps: drying, thermal decomposition (also called dry distillation), reduction, and oxidation. Among them, the drying layer needs a temperature of 100-250 degrees, the thermal decomposition layer needs 300-800 degrees, the reducing layer needs about 900 degrees, and the oxide layer is about 1200 degrees. The gasification process of straw gasification is generally upward suction and downward suction.
There are two types, in simple terms, the upper suction type, that is, the raw materials are put in from the upper inlet, after drying, thermal decomposition (also called dry distillation), reduction, oxidation, four steps, and the bottom is forced to blow by a fan, and the gasification occurs The upper part of the gasification generator outputs fuel gas, and the downward suction type is input from the upper inlet, after drying, thermal decomposition (also called dry distillation), reduction, oxidation, four steps, the lower part of the gasification generator is forced to input fuel gas with an induced draft fan.
The suction fixed bed gasification process can crack the tar a second time, which can effectively reduce the tar content in the product. Therefore, the applied process is mainly the following suction fixed bed generator. The standard overall straw vaporization process is as follows: First, straw and other raw materials need to be dried naturally, and then crushed into a length of 3mm-30mm with a pulverizer (the pretreatment of raw materials has little effect on the tar content, which mainly affects the efficiency of gasification. ), put into the gasification generator, after drying, thermal decomposition (also called dry distillation), reduction, oxidation four steps to generate combustible gas, and then through the dust collector to remove dust, and then through the spray purifier, steam separator, filter, Finally, it enters the gas storage tank, which is the qualified combustible gas that can be used. Then it is sent to the people's homes for burning.
