The Research On Combustion Process Of Rice Husk In Chain Grate Boiler

In the constitution of energy consumption in our country, coal is the main energy, air pollution as well as carbon dioxide emissions intensity are caused by coal mining and use. As an alternative fuel to coal, biomass has been paid more and more attention in recent years. It is a low cost, energy-efficient technology path to replace coal with biomass.This subject comes from a research and development project. In the project, rice husk is combusted as well as carbonized rice husk is produced. A steam boiler SZL10-1.25-A11 was developed by using rice husk fuel to replace coal which is the original design fuel. Because of a broad market and economic value of the carbonized rice husk, the objective of this project is to ensure the supply of steam as well as produce carbonized rice husk. A suspension system is used for rice husk paralysis because of low calorific value and bulk density of rice husk. The combustion stability and initial thickness of the bed are significantly improved. Fly ash can be also reduced.In this paper, three different pre-arch structures are developed for combustion of rice husk, and a new type burner was developed to match with the pre-arch structure. Fluid simulation software Fluent is used to simulate the air flow fields in the furnace of different pre-arch structures. Secondary air is considered in the simulation. One pre-arch is selected by analyzing air flow fields in the furnace of different pre-arch structures. This pre-arch structure has positive significance in the turbulence organization, residence time of air flow in furnace and blockade of fly ash. In order to make boiler operate continuously and steadily, some systems such as conveyor of rice husk, boiler deduct system, monitoring system are designed.The result of different conditions shows that the boiler not only ensures the supply of steam but also can produce carbonized rice husk of different fixed carbon. Corresponding to 30-110% of range, boiler evaporating capacity can be adjusted between 3t/h to 11t/h. The expectation aim can be realized.