粉煤催化气化含碱灰渣与助剂煅烧脱碱

Calcination de-alkali with additives for alkali coal-cinder produced from the catalytic gasification of pulverized coals

采取静态煅烧研究了助剂对8种无烟粉煤催化气化后的含碱灰渣中碱含量的影响,并在小型流化床中进行工业化过程模拟.结果表明:含碱灰渣脱碱率随助剂浓度的增大、煅烧温度的升高及时间的延长而提高;最佳的脱碱助剂均为高岭土,当其添加浓度为5%时,在870℃煅烧30-40 min,灰渣脱碱率即可接近100%,流化床煅烧与静态煅烧相近的实验结果为工程应用提供了理论依据;采用XRD及SEM对煅烧后的灰渣进行表征,揭示了助剂煅烧脱碱过程的实质,即在适宜煅烧温度下,助剂中被活化的主要物质SiO2、Al2O3和灰渣中熔融并分解的Na2CO3等发生化学反应转变为难溶于水的钠铝复合硅酸盐.

The effects of additives, calcination temperature and time on alkali content of coal cinder, yielded from catalytic gasification of eight kinds of anthracite, have been first examined using the static calcination method in a laboratorial high temperature furnace. The results indicate that the optimum de - alkali additive of the eight kinds of coal cinder is kaoline, under adding 5 % kaoline in the coal cinder and calcination temperature ： 870 ℃ for 30 - 40 minutes, the de - alkali rate can be raised up to 100%, therefore the harmless treatment of alkali coal cinder can be achieved. The same results, obtained by calcining the coal cinder in a small fluidized bed, with which get from the static calcination method provide theoretical foundation for industrial scale -up. With analyzing the calcined cinder by XRD and SEM, it is clear that under an appropriate temperature, the activated SiO2 and Al2O3 contained in additives will react with fused Na2CO3 and form a new neutral compounds of sodium and aluminium silicates undissolved in water.