Coal characteristics and slagging property of Xinjiang coal for gasification

Xinjiang has abundant coal reserves. Xinjiang coal has high reactivity and is suitable for coal power and coal chemical production. As the third generation of advanced gasification technology,catalytic coal gasification technology is one of the most effective processes for coal to natural gas. Coal characteristics and slagging property of six kinds of Xinjiang coals from lli and Zhundong coal chemical industry base were systematically investigated,and the applicabili- ty of coal for catalytic coal gasification process was inspected,which can provide guidance for the coal selection and utilization of coal to gas project in Xinjiang. A homemade pressurized pressure-drop measuring device was used to de- termine the ash sintering temperature of different coal ash. An X-ray diffractometer (XRD) in combination with Fact- Sage were used to predict the reactions occurring between minerals as well as the mineral transformation and slag for- mation,and reveal the mechanism of slag. The results show that the coal in the selected area has relatively high slag- ging risk for the coal gasification process because of the low refractory compound alumina,high alkaline compound and low ash melting point. The ash melting point of the selected Xinjiang coal is low. XHS and DJ coal with high potassi- um,sodium and low aluminum characteristics are easier to slag,and have a higher slagging risk for catalytic coal gasifi- cation process. The HM coal with relatively high melting temperature is not easy to slag when used for catalytic coal gasification. The sintering temperature of coal loading with potassium carbonate catalyst decreases significantly. The in- fluence of calcium catalyst addition on sintering temperature is greatly influenced by the ash composition of coal. Adding K catalyst will further aggravate slagging when coal ash has higher silicon content. There is a greater slagging risk for coal with higher iron content,and the addition of K and Ca catalysts will aggravate the slagging problem in the reducing atmosphere. For the coal with low ash content,the addition of potassium carbonate catalyst has great influence on the ash melting point and sintering temperature;under the catalytic gasification condition,the presence of silicon,i- ron and calcium minerals in the ash aggravates the slagging.