Experiment And Numerical Simulation Of The Char Particle Combustion

Coal makes up most of China's total energy output and consumption, in current and future longer period of time in China, the condition that coal is the main energy in China will not change. China is rich in coal, as the consumption of the coal largely increased and the restriction of the coal production and the traffic levels, and the movement of the international coal market, Coal prices have shot up recently. About 84% coal is directly for combustion, and the char burnout time normally accounts for over 90% of the pulverized coal particles in the furnace total burning time, to utilize the coal in a better way and to improve coal economy, research on combustion of the char is necessary.In this paper, TGA and DTF, respectively, are used to study the combustion characteristic of the particles char in different temperatures, the relationship between crystallite structure of char and reactivity was studied by XRD. In addition, Programming was used to study the combustion of the single particle char.The gasified semi-coke obtained from the secondary cyclone of the Jincheng Industrial gasifier was selected as one of the samples for the study, in addition, three chars were yielded by the investigation of the Jingneng bituminous coal in a drop tube deposition furnace at fast pyrolysis temperature of 1173K,1273K,1373K.The combustion behavior of the four chars above mentioned was performed by TGA/SDA851e under the condition of different constant temperature. The reactivity of Jinchen semi-coke is the least, and the reactivity of the rest chars decreased as the pyrolysis temperature raised; raising temperature and increasing the concentration of the oxygen were positive to the char combustion. After the data analysis, half-life time method and isoconversional method support each other; Grain model predicted the combustion behavior of the four chars at low temperatures. The reactivity was unrelated to the microcrystalline layer spacing, decreased with the microcrystalline stacking height increased. Semi-coke combustion characteristics test at 1273K and 1573K have be done in the DTF. Both burnout at 1273K and 1573K increased with the residence time increased, and the combustion at 1273K was in Regimeâ…¡; The burn rate was determined by Central Difference Method, and it decreased with the residence time increased; The pore structure and pore size distribution of the products of the combustion received at 1273K(at 5% and 20% oxygen concentration respectively) were measured by the apparatus of the Micromeritics U.S. companies ASAP2000 automatic adsorption instrument, pore-size distribution change little, specific surface area and pore volume decreased with the char burning.To simulate the temperature distribution and the gas concentration distribution in the carbon as the carbon burning at some constant temperature, programming was based on the test of the char combustion. Numerical computation was used to study the combustion characteristic of the particles char. Compared boundary temperature and gas concentration, Using trial and error method, the burn rate of the carbon was received after compared with the experimental value.