Study On Compound Modifying And Sulfur-fixing Of High Organic Sulfur Coal

In order to improve sulfur fixation efficiency of high organic sulfur coal, this paper put forward a new idea “processing-fixation bonding, compound modifying”, accordance with the thought of synergistic interaction. Influence of compound modifying agent on sulfur fixation efficiency, combustion and ash characteristics were studied.The high organic sulfur coal was collected from Henan Yima mining area, experimental methods of reducing coal ash, expanding modified space were discussed. Based on comprehensive consideration of size distribution, density distribution, optional and energy consumption of raw coal broken to different particle size, 6mm was thought to be optimal crushing size limit. Then, high calorific value coal was obtained by conventional separation methods.Limestone and carbide slag ware selected as main sulfur-fixing agent, Al2O3、Fe2O3 and SiO2 were selected as sulfur retention additives, Influence of main sulfur-fixing agent and sulfur retention additives on sulfur fixation efficiency was studied, with the constraint condition of calorific value, the evaluation index of sulfur-fixing rate. The optimal desulfurization conditions were determined: combustion temperature was taken 900℃, combustion residence time was taken 10 min; The optimum proportion of limestone and carbide slag was molar ratio of 4:6, the optimum proportion of Al2O3、Fe2O3 and SiO2 was molar ratio of 1:1:1, the optimum adding amount of sulfur retention additives was 1% of the based coal quality.The effect of modifying agent on calorific value of coal has two aspects: on the one hand, adding sulfur fixing agent can increase the ash content, leading to the decreasing of calorific value; on another hand, the process of desulfurization reaction can release heat, so the calorific value of the majorized coal is higher than conventional coal with same ash content.The combustion characteristics of majorized coal was studied by thermogravimetric analyzer(TGA), the results showed that: the activation energy of majorized coal was higher than conventional coal in low temperature region, resulting in slower heat release rate, the activation energy of majorized coal decreased in high temperature region, heat release rate speeded up.Fe2O3 as combustion improver, can decrease the activation energy, speeding up the process of combustion. The adding amount of Fe2O3 taken 1% of the based coal quality was the best additive for the combustion-supporting character.Ash composition of majorized coal was analyzed by XRF and XRD, f-CaO and Ⅱ-CaSO4 was found in majorized coal ash, which was markedly different from that of conventional coal ash. Auto-hydraulicity strength of majorized coal ashes was determined, the results indicate that majorized coal ashes have a certain compressive strength, can be used as cementing material.