Optimization Of Blending Coals In The Power Plant And Research Of Coal Additives

Low quality coal is mainly burned in the coal-fired power plants of our country. With the growing shortage of energy, the quality of coal burned in the power plants is changing, mostly to the worse. An effective way to improve the adaptability of coal used in the plants is to take the respective advantages of the single coal by mixing them all together. In order to meet the tighter regulation and standards for emission of environment pollutants for thermal power plants, denitrification technologies in furnace and for flue gas are adopted, which unfortunately leads to a discount in efficiency of combustion or a higher power consumption rate. In order to solve the problem, coal additives are being researched more and more. So, optimization of blending coals in the power plant and the influence of coal additives on the combustion and the NOx emissions are studied in this thesis.Routine analysis and thermal analysis of 19 kinds of coals used in a power plant A are conducted. According to the principle of blending, the parameters of coal are weighted averaged except the ash melting point, which is predicted through the support vector machine and the grid search. The prediction error is proved to be small. The mixed coal related to power plant A and the blending ratio are sorted according to the price of blending coal. The simulation shows that NOx emissions can meet the requirements. The problem of the safe and economic operation caused by the change of coal quality can be improved.Thermo-Gravimetry (TG), tube furnace and tube drop furnace test on different kinds of coals mixed with MMT were carried out to analyze the influence of the additives on the combustion characteristics, NOx emission characteristics and overall properties. These tests indicate respectively that the coal additives can catalyze the combustion of coke, restore coke NOx and reduce the carbon content of fly ash and NOx emissions at the same time. Conclusion of these trials reveals that the decomposition products of additive MMT can catalyst not only the combustion of coke, but also the reduction of C or CO on the NO.Both NOx and the carbon content of ash and residue are decreased in the practical application of the power plant. It achieved the aim of the combination of energy-saving and emission reduction.