Coal slag viscosity behavior

Figure 4.2 Coal slag viscosity behavior under reducing atmosphere [15].

Although the data obtained in these studies have been valuable in interpreting the slagging phenomena observed in gasifier tests, a more fundamental objective of the current work is to develop correlations that can be used to predict a priori the viscosity behavior of low-rank-coal slags from a knowledge of the ash or slag composition. 

The purposes of this study included a determination of the viscosity behavior of synthetic slags over a range of compositions and temperatures characteristic of slagging gasifier operation. The compositions were chosen to be broadly representative of a range of coals from both the eastern and western U.S. The temperatures were chosen to be in the range of satisfactory gasifier operation, and within the limits of the experimental equipment. 

Ash yield between 6% and 25% for bituminous coal, or 4% and 25% for subbituminous coal—the ash must have particular slag viscosity characteristics since ash slag behavior is critical to satisfactory operation, and the maximum temperature at which the slag has a viscosity of 250 cP is 1340°C (2445°F) for bituminous coal and 1260°C (2300°F) for sub-bituminous coal. 

---