Jincheng Coal Research Articles

EFFECT OF CHEMICAL COMPOSITION ON SINTERING BEHAVIOR OF JINCHENG COAL ASH UNDER GASIFICATION ATMOSPHERE

In order to obtain detailed understanding of coal ash sintering behavior, a series of experiments have been done on the effect of Jincheng coal ash composition on sintering temperature under gasification atmosphere by the pressure-drop technique. The mineral transformations within its sintering temperature range are simulated by the thermodynamic equilibrium calculation module of FactSage to better understand the experiment results. These results show that the sintering temperature decreases initially, and then rises with increasing SiO2. On the whole, the sintering temperatures decrease with increase in Fe2O3, CaO, Na2O, and K2O. Their effects are quite similar, but the degrees are different. As MgO increases, the sintering temperature decreases. However when MgO is increased above a certain limit, the effect of MgO on the sintering temperature is not obvious.

Effect of different reaction atmospheres on the sintering temperature of Jincheng coal ash under pressurized conditions

The sintering temperature of coal ash is studied to further understand ash behavior. The objective of this study is to obtain a detailed understanding of the effect of the reaction atmospheres on the sintering temperature under elevated pressure. A series of experiments and analyses have been completed using a pressurized pressure-drop measuring device and X-ray diffractometer (XRD) analyzer. The results show that the sintering temperatures decline markedly under all reaction atmospheres with the rise in pressure. The pressure influences the sintering temperatures by affecting the reaction rate and the mineral transformations undergone by the coal ash, as observed from the XRD patterns. The sintering temperatures measured under the reducing reaction atmospheres are lower than those for oxidizing atmospheres. The sintering temperature under N2 is lower than those under other oxidizing atmospheres. The sintering temperature under the gasification atmosphere is close to those under H2 and CO atmospheres, whereas the sintering temperature under a H2 atmosphere is lower than that under a CO atmosphere.

Characteristics of fissures and pores of anthracite in Jincheng by SEM

Anthracite in Jincheng is a highly metamorphic coal and its system of fissures and pores is differentfrom that of low and medium ranked coal. In order to discover their characteristics, 69 samples were collected from 18 CBM wells in Zhengzhuang in Jincheng and their fissures and pores were observed by a Scanning Electron Microscope (SEM). To the naked eyes and by SEM, the pores in the Jincheng anthracite are seen to have abundant mold pores with isolated, shallow and poor connectivity (diameters between 1∼50 μm) and few plant tissue pores, gas pores, and solution pores. Most of the fissures are filled with clay minerals or closed; while open fissures are not often visible in the Jincheng coal (aperture between 3∼10 μm). These characteristics are determined by the high rank and high vitrinite content of the coal. The existence of too many mold pores and filled fissures does not allow the migration of methane, hence hydraulic fracture stimulation will be required and is an effective method of adding and connecting fissures to enhance CBM production.