Study On Combustion Characteristics Of Pressurized Coal At Oxygen Enriched Condition

O2/CO2looping combustion is a new prominent combustion technology in CO2recovery processing, which greatly reducing the emissions of CO2and improving the coal combustion efficiency at the same time. But in the application of O2/CO2looping combustion, the air separation and CO2compression are under high pressure, while the furnace combustion process is under atmospheric pressure, the inconsistent pressure of the whole process lead to energy consumption. Increasing the coal combustion pressure can further improve thermal efficiency and reduce coal used amount and meet the power demand, also can further reduce CO2emissions. However, few research about coal combustion reaction mechanism in pressurized oxygen-enriched combustion process at home and abroad. Researching coal combustion reaction mechanism in high pressure and exploring its effect on coal combustion will help O2/CO2looping combustion in-depth development. Experiment and theoretical analysis are used in the following aspects.Firstly, the pressurized non-isothermal thermogravimetry experiments of bituminous coal and anthracite were conducted in a pressurized thermogravimetric analyzer. The results show that the ignition of pulverized coal oxygen-enriched combustion mechanism changed, the non-homogeneous ignition turned into homogeneous ignition in2MPa. And with increasing pressure, the ignition point and maximum burning rate point and burn out point were gradual decline. The volatile burning rate accelerated by high pressure and the degree of pyrolysis of pulverized coal gradually deepened with increasing pressure. Due to less contents of volatile, high pressure affect less the combustion properties of anthracite, but the increasing pressure can improve anthracite combustion.Secondly, through theoretical analyzed coal ignition mechanism, found out that accelerating volatile precipitation speed was the major factor lead to ignition mechanism changed. And reach the oxygen concentration in the pulverized coal unit area was increased. Then using the heat balance principle analyzed the ignition point and burn out point forward reason in the view of balance move, found out that due to gas density increase in high pressure,cooling curve slope become larger, the balance point forward to the low temperature.Finally, to further study the combustion characteristics of pulverized coal under high pressure, the flow tube furnace with pressure of8Mpa was designed and constructed. In the process, tightness and security under high pressure were fully consideration. Arrangement the precision temperature measurement system to satisfy the demand of pulverized coal ignition point measurement. The experiment systems also including powder feeding system, the reactor system, flue gas analysis system and auxiliary systems, which can lay the foundation for future work.