Huang Jiejie

Effect of calcium oxide on pyrolysis of coal in a fluidized bed

The pyrolysis of Shenmu bituminous coal in both the presence and absence of calcium oxide was studied under atmospheric pressure over a temperature range of 450–750°C in a fluidized bed reactor. Calcium oxide significantly increases the gas yield while decreasing the tar yield. Tars produced in both the presence and absence of calcium oxide were analyzed and compared. The results indicated that tar yields reach a maximum at 650°C for coal pyrolysis without calcium oxide, in accordance with Tylers results. When calcium oxide is added, the temperature of tar maximum yield is reduced to 550°C. It is also demonstrated that the ratio of H/C; benzene, toluene, xylene (BTX); phenol, cresol, xylenol (PCX) and other light components in tar increase while the ratio of (O+N+S)/C and oxide compounds in tar decrease in the presence of calcium oxide. It is noted that the maximum composition of alkanes in tar is C14–C20 in the presence of calcium oxide, while it is C8–C15 in the absence of calcium oxide. It results from the fracture of alkanes with long chains to alkanes with short chains when calcium oxide is added.

Utilization of Fly Ash to Prepare Adsorbent for SO2 Removal in Flue Gas

The possibility of preparing formed active coke using fly ash from a fluidized bed coal gasifier for flue gas desulfurization was investigated. The study shows that fly ash can be utilized as the feedstock with the addition of some raw coal. The obtained formed active coke exhibits an almost equivalent desulfurization capacity to that from raw coal. In addition, the effects of the pore properties and surface chemical properties of different formed cokes on SO 2 removal were analyzed and discussed. The effect factors on the mechanical strength of formed coke and optimal preparation conditions were also discussed.