Study On The Oxygen Transfer Laws During Coal’s Pyrolysis Process And Its Effect On The Coking Property

Oxygen is one of the most important elements of coal.The form and content ofoxygen in the coal directly affect the process nature of coal and the coal coking.Thispaper selected gas coal, gas and fat coal,1/3coking coal, coking coal and ShenhuaCoal as the research object.Independent research of fast pyrolysis device was used inlow-temperature pyrolysis of coal to explore the migration of oxygen during coalpyrolysis and its effect on coke coking to explore the migration of oxygen duringcoal pyrolysis and its effect on coke coking.The results showed that:(1)For the different ranks of coal, as the coalification degree of increase, the oxygencontent and the hydrogen content of the coal gradually reduced while the carboncontent increased.Phenolic hydroxyl group and carboxyl group contents werereduced and there was substantially no carboxyl group in the1/3coking coal andcoking coal. Study on the pyrolytic kinetics for medium rank coal indicated that thesequence of the energy needed during the pyrolysis process is gas-fat coal>gascoal>1/3coking coal> coking coal.(2)The study of the different-ranks coal before and after treatment finds that whenthe treatment temperature increased, the carbon contents in Shenhua coal increased,while its content of hydrogen and oxygen decreased, the content of carbon andoxygen in gas-fat coal decreased first and then increased, the hydrogen contentdecreased, the content of acidic groups, carboxyl and phenolic hydroxyl in coalshows a trend of increasing first and then decreasing, Shenhua coal showed the besteffect of removing the functional groups. The weight loss of the coal sample isdeclining in TG curve (except1/3coking), the peak temperature of coal sampleincreased gradually in the DTG curve, and its responding peak is decreasing. Therelative caking index of Shenhua coal tended to increase first and decrease then, andhas a good corresponding relationship with the content of phenolic hydroxyl groupin coal; the caking index of gas coal, gas-fat coal,1/3coking coal and coking coaldecreased continuously.(3)Research on the coking experiments of Shenhua coal before and after treatmentshows that, there’s improvement on the reactivity and microstructure strength ofcoke produced from the shenhua coal after treatment to some extent, while thestructural strength changes little. The content of oxygen-containing functionalgroups of coals shows a relationship with the PRI, and they both shows a trend of decreasing first and then with the increasing treatment temperature.