Experimental Research And Analysis On Biomass Forming Process And Combustion Performance

Biomass resources in China are relatively richer than other countries. But these rich biomass resources are often dispersed more widely, loose and in irregular shape, so there will be many difficulties in transporting and storing biomass.Besides, the energy efficiency of biomass is very low. This is precisely the bottleneck that constraints biomass resources to achieve large-scale utilization for many years. To solve the above problems, a large number of domestic and foreign scholars have developed biomass briquetting technology. The irregularly shaped and loose biomass can be compressed into regularly shaped and high-density biomass briquettes, which made the biomass resources become upper-grade energy from a low-grade energy and provided a strong guarantee for the large-scale application of biomass resources.Currently, domestic and foreign scholars have made a lot of research on biomass briquetting technology. But there are still shortcomings of high energy consumption per unit of production and short life of briquetting equipment. To compensate for these shortcomings, we have made some research on the different biomass briquetting process and the combustion performance of the biomass briquettes. The specific research mainly includes the following three parts:Firstly, we design two small briquetting mold include cold and hot press briquetting mold and select the wheat straw and corn straw as briquetting material. Then we conduct cold pressure briquetting trials in different material particle size, moisture content and briquetting pressure. By the calculation of briquetting density and defensive crushing strength, we obtain the optimum briquetting parameter combination. Then we conduct binder-addition cold pressure briquetting and hot pressure briquetting trials respectively and also calculate the briquette density and defensive crushing strength. Ultimately, we determine the optimum briquetting process through the comparison of the above three briquetting process.Secondly, we make a brief introduction on the characteristics of biomass residual carbon. And then we select the corn straw, wheat straw and biomass pyrolysis tar as the binder of orthogonal test on biomass residual carbon briquetting. Among this orthogonal test, the addition amount of binder, moisture content of biomass, briquetting pressure and briquetting temperature are the main orthogonal test factors. Each of these factors is taken three representative levels. Finally, we obtain the impact order of the above four factors on biomass pyrolysis residue carbon briquetting through the calculation of briquetting density and compressive strength of the briquette.Thirdly, we make a brief introduction on the combustion theory of briquette. And then we put the biomass raw material and the briquette into the combustion furnace. We calculate the combustion heat efficiency and the carbon content of ash after combustion of them and analyze the flue gas composition generated from the combustion of them respectively. Finally, we compare the results of calculation and analysis. The results show that the occurrence of biomass briquettes’combustion is much easier than loose biomass raw material, the combustion heat efficiency is greatly increased and the combustion performance has been greatly improved.