Study On Pyrolysis For Improving Coal Desulfurization And Deash Effect Of Magnetic Separation

It is of great significance to improve the desulfurization and deash effect of pulverized coal magnetic separation by enhancing the pyrite magnetism before coal preparation. The article mainly studied the effect of heat treatment on desulfurization and deash of pulverized coal magnetic separation. The main contents included the relation of heat temperature with sulfur, magnetic separation desulfurization rate and deash rate with susceptibility. And the effect of the atmosphere and catalyst on magnetic separation desulfurization rate. At last discussed the effect of heat treatment on the removal of organic sulfur.The magnetic susceptibility of pyrite in Yiluo was studied, then thermal decomposition temperature range was analyzed using TGA analysis. The magnetic susceptibility under different temperature was also measured. The result showed that: the thermal decomposition of pyrite is the main reason for magnetic enhancement. The pyrrhotite was found when temperature between 600 ~ 700℃and when 700℃the pyrite was completely transferred into pyrrhotite, at the same time the susceptibility was increased more than two magnitude as well as non-heatment. The heat treatment temperature and the susceptibility values of pyrite satified the first-order exponential growth in line by using software Origin.The coal from Yankuang Beisu and Xishan Lingshi were carried out heatment under nitrogen atmosphere by self-made heat treatment device. The device has many advantage over traditional device, such as large capacity, easy to operate and can combine with the magnetic separation after heat treatment. The result showed that: heat treatment temperature has great effect on the magnetic susceptibility values. So it is essential to choose appropriate heat treatment temperature. When 500℃the maxium magnetic separation desulfurization rate was got. The rate was increased 40.51 percent and 23.48 percent for Beisu and Lingshi coal respectively compared with non-heat treatment sample. The deash rate of Beisu was increased 35 percent. This showd that heat treatment can effectively improve the magnetic desulfurization and deash rate of pulverized coal .By comparing the high-temperature water vapor atmosphere and nitrogen atmosphere on the magnetic desulfurization rate of coal, it showed that: the high-temperature water vapor atmosphere can promote the decomposition of pyrite in coal and decrease the sulfur content. But in the atmosphere of the trial after heat treatment, the magnetic desulfurization rate did not increase as compared with non-heat-treatment samples. The nitrogen atmosphere was more fit for heat treatment reaction atmosphere. The catalyst can not only effectively improve the magnetic desulfurization rate of pulverized coal, but also increase the magnetic desulfurization.In order to study the effect of heat treatment on organic sulfur removal by magnetic separation , the Indonesian high sulfur(organic sulfur accounted for 84% of sulfur )was chosen for experiment. The result showed that: the teat treatment can reduce organic sulfur partially, but the magnetic separation can't reduce the organic sulfur even after heat treatment.