The Numerical Simulation About The Biomass Briquette Combustion

Biomass fuels are gaining increased public and scientific attention, driven by factors such as widely distributing, less combustion pollution and the need for increased energy security. Biomass fuels can be used by directly burning, or making into bundles or briquettes to burn. In this paper we make the biomass fuels into a certain shape and size of the briquette to burn.Chain grate are used in the burning of biomass briquette. This kind of method has already widely being accepted and the combustion efficiency has been improved significantly after a lot of study. However, lacking in theoretical studies, people renovate chain grate only by rule of thumb.According to the combustion theory and the characteristics of the biomass briquettes, we present a numerical simulation method for the combustion of the fuel in the chain furnace and proposed the key furnace structure for this kind of fuel. In what follows, the major elements are:(1) Two wood biomass briquettes and a coking woody biomass briquettes are investigated in this paper. In order to determine the difference from coal fuel in performance, coal fuel is also investigated. Proximate analysis, elemental analysis, determination of calorific value, ash melting point and ash component analysis are performed to provide experimental data for the numerical simulation for biomass briquette.(2) In this paper, biomass briquette combustion numerical simulation on chain grate are presented. For the reason of high volatile content of the fuel and Fluent can simulate gas combustion well, the numerical simulation is proceed from two parts. The fist part is using finite difference method to calculate moisture precipitation, volatile precipitation and fixed carbon combustion process. Language in programming is C. The second part is to obtain the temperature distribution in the furnace and the concentration distribution of the individual components by using Fluent to simulate volatile gases’ combustion process in furnace with the solution obtained from the first part as the boundary condition.(3) In this paper, we implement the numerical simulation method referred in (2) to simulate the combustion phenomena in boiler. The result from numerical simulation is used to guide us to refine our furnace structure.