Optimization And Nonlinear Prediction Of Combustion Characteristics Of Coal Blends

Blending coal technology originated in the United States, as a clean coal technology, have been applied in some large cities in China in the 1980s. In recent years, Blending coal technology developed quickly in China, especially in improving the burnout efficiency of coal, strengthening the safety and reliability of coal-burning equipment and reducing pollutants emissions. It had a wide range of engineering applications and a high research value.In this article firstly obtained the coal ignition temperature and the activation energy of 16 coal and 48 blending coal using thermal analysis. The correlation analysis of the coal ignition temperature and the activation energy with the proximate analysis and ultimate analysis of coal samples showed that M_ad, V_ad, FC_ad, Q_net,ad and Q_ad five factors had a stronger relationship with ignition temperature and activation energy. And then used ignition temperature and the activation energy as output for the establishment of three-layer BP artificial neural network model, after the network received training in the ignition temperature is forecast to average relative error of 1. 22%, the activation energy of the average forecast error is 3.89%.Second, Shenhua coal and Datong coal which were high fever, low ash and easy to slag were used as the main study subjects, Zhungeer Coal and Australia coal which were high-ash melting point were chosen to make a different weight ratio of blending coal. Blending pore fractal dimension with the proportion of coal showed a single monotonous change in the law, and with the surface area and pore volume than the changes of the basic agreement. Compare it with the experimental results by drop-tube furnaces, found that when blending coal fractal dimension gradually increased to 2.426 from 2.532 and 2.451,2.482, its ignition temperature gradually reduced from 882℃to 783℃, 587℃and 462℃, their ashes carbon content decreased by 4.81% to 3.62%, 2.83% and 1.83%. It noted that the greater the fractal dimension of the blending coal the easier its fire and Burnout.Finally, blending coal expert system which was developed by Zhejiang University was used in the project of Shaoguan power plant, 11 kinds of blending coal with two components were given according to the goal coal characteristics of Shaoguan power plant, then the characteristics of different blending coal was studied in the drop-tube furnace. It showed that increased the temperature of furnace wall and air or reduced the size of pulverized coal could promote anthracite fire and Burnout. The blending coal "M0007 coal 25% + M0011 coal 75%" , at the standard condition, change the furnace wall temperatures only, when the furnace wall temperature increased from 1100℃to 1200℃and 1300℃, the ignition distance reduced from 400mm to 300mm and 280mm, carbon content of fly ash reduced from 9.09% to 6.60% and 1.17%. The temperature of air and the size of pulverized coal showed a similar change in the law.