Study On Pressurized Oxy-fuel Combustion Characteristics Of Pulverized Coal

Oxygen-enriched combustion technology (OCT) is a new kind of coal combustion technology which is environmental friendly. The principle of oxygen-enriched combustion technology is to obtain mixture of high purity oxygen using air separation and part of the boiler exhaust (mainly CO2and H2O) instead of air as oxidant of burning, so that the CO2concentration in combustion exhaust can be increased greatly. Also, high concentration CO2is beneficial to separation and storage. OCT is one of the most promising near zero emission coal technology in recent years. Based on the oxygen-enriched combustion principle, the pressurized oxygen-enriched combustion emerges, which has obvious technical and economic advantages. Currently, researches on oxygen-enriched combustion technology domestic and abroad focus mainly on the numerical simulation and the oxygen-enriched combustion of pulverized coal combustion mode and burnout characteristics through thermogravimetric experiment, therefore, the experimental research on combustion process of pressurized oxygen enriched pulverized coal combustion, the effects of pressure on pulverized coal combustion characteristic, will contribute to the healthy development of pressurized oxygen-enriched coal combustion technology. In this work, experimental study and theoretical analysis are done and the following issues are discussed especially.First, analyzed coal combustion process in the pressurized oxygen-enriched atmosphere using Aspen Plus process simulation software, studied the influence of pressure on combustion products. Then finished the design, installation and debugging of experiment device of pressurized fixed bed reactor, ensured that the experimental device was safe and reliable. Finally, carried out the pressurized oxygen enriched pulverized coal combustion experiment in the pressurized fixed bed reactor, analyzed the influence of pressure on pulverized coal oxygen-enriched combustion characteristic and flue gas composition. Results showed that comparing to oridinary pressure, burning time under the condition of pressurized O230%/CO270%atmosphere increased with pressure increase. Burning time under working condition of5MPa was the longest and burning time under working condition of3MPa was most close to normal pulverized coal oxygen-enriched combustion. The highest temperature combustion increased with pressure increase obviously, reached the highest at2MPa. Combustion rate under different pressure condition showed difference. The O2concentration in flue gas under different pressure showed similar trends, conditions of0.1MPa,4MPa,5MPa went through the process of fall after rise. CO concentration in the flus gas under different pressure also showed similar trends. Compared to the atmospheric pressure, CO concentration under pressurized condition decreased significantly. During the whole process, CO2concentration increased with pressure increase, CO2concentration under different conditions undergone a certain fluctuation.