An Experimental Study On The Chemical Reaction Kinetics Of Coal Combustion By Thermogravimetry Analysis

Pulverized coal combustion performance has important influence on boiler design , alteration and combustion adjusting, and it is also a basis of specialized boiler . For modern boilers, practical experiences of many years show that coal conventional analysis numerical value is very limited to forecast pulverized coal combustion process, General conventional industrial analysis datum and element analysis datum can not meet its request , designed boiler safety and boiler economic operation can be guaranteed on condition that the ignition,burnout and slagging characteristics of pulverized coal must be understood. Radiative image processing techniques have been used as effective tools for flame study, for temperature measurement, for combustion analysis based on temperatures obtained from flame images, and for combustion control. The idea of reconstruction of 3-D temperature distributions in furnaces through radiative energy image processing was studied numerically.A combustion model connected burnout with chemical dynamics parameters and quantitative study on it are rarely reported. Pulverized coal combustion reaction dynamics parameters are one of necessary important datum of thermal calculation on combustion equipment based on pulverized coal fuel and basic theory study on pulverized coal particle combustion characteristics .With the development of computer science , mathematical model of pulverized coal combustion is being applied to boiler design and operation little by little. This is required to calculate pulverized coal combustion process as accurately as possible, important initial data in the calculation is reaction dynamics parameters, it quantitatively describes reaction ability of coal and gives change rule of reaction ability of different coals with temperature . According to need of HuNan Hua-Yin ZhuZhou power plant' 2nd alteration project , fifteen conventional coals that they provided and will burn in the power plant' W flame furnace are studied on conventional industrial analysis, element analysis ,actual combustion characteristics and slagging characteristics. Adaptation reactions of coals are analyzed, coal ranges selected of better combustion effect in the flame furnace is given., ground is provided for determining burning coals. A combustion model is provided , the model consider the apparent activation energy and the pre-exponential factor as function of burnout , its meaning has two sides : under different burnouts, combustion characteristics are different; under the same burnouts, combustion reaction chemistry dynamics constant is identical. Detailed study process is below: TG, DTG curves under different temperature increasing rates for an identical coal by a thermal balance TGA7 can be obtained, and the curves of the combustion rates and the temperatures varied with the burnout ratio can then be got. By the experimental data under two temperature increasing rates, the curves of the apparent activation energy and the pre-exponential factor varied with the burnout ratio can be calculated. The curves of and for four coals were obtained by the method, and the combustion rate varied with the burnout ratio for one coal under a third temperature increasing rate was calculated, which agreed well with the experimental results. Study on combustion characteristics of blended coal by thermogravimentric analysis is made . The change trends of the combustion rates for the several coals under different constant temperature levels were predicted. Analysis results that are similar to furnace temperature are gained further . It has particular use for reference for simulating combustion process of boiler furnace.