中药渣与污泥循环流化床共气化特性试验研究

Experimental Study on Co-gasification Characteristics of Herb Residue and Sludge in Circulating Fluidized-bed

中药制药过程产生中药渣、污泥等废弃物,如何实现再利用对中医药产业的科学发展具有重要的经济与社会意义。文章以中药渣与污泥为原料,采用循环流化床气化炉进行共气化试验,分别研究了空气当量比、污泥掺混比、原料含水率对气化系统运行参数及气化产物的影响规律。结果表明:空气当量比是中药渣与污泥共气化的关键影响因素,空气当量比由0.25增大至0.45过程中,气化炉温度及物料的碳转化率均有升高,气化燃气热值与焦油质量浓度下降,CO体积分数与气化效率出现先增后减的变化;空气当量比为0.35时气化效率达到最大值68.42%,对应的燃气热值为5.47 MJ/Nm^3。适量掺加污泥或提高原料含水率,有利于气化反应,可以提升气化效率改善气化效果,对于中药渣与污泥的共气化,较佳的污泥掺混比及原料含水率均为15%。

Herb residue and sludge are produced in the pharmaceutical process of Chinese medicine,and their reuse is of great significance for resource conservation and environmental protection.The experiment of co-gasification of herb residue and sludge was carried out in a circulating fluidized bed gasifier.The effects of air equivalent ratio,sludge mixing ratio and moisture content of raw materials on gasification characteristics such as operating temperature,pressure,gas composition,calorific value,tar mass concentration,gasification efficiency and carbon conversion ratio were studied,respectively.The results showed that air equivalence ratio is the key factor to affect the co-gasification of herb residue and sludge.With the increase of air equivalence ratio from 0.25 to 0.45,the operating temperature of circulating fluidized bed gasifier and carbon conversion rate increased,while the calorific value and tar mass concentration decreased.The volume fraction of CO in product gas and the gasification efficiency increased first and then decreased.When air equivalence ratio was 0.35,the gasification efficiency reached the maximum of 68.42%and calorific value reached 5.47 MJ/Nm3.The results also showed that proper addition of sludge in herb residue or increase of moisture content can improve the quality of gasification gas and improve gasification efficiency.For co-gasification of herb residue and sludge,the better sludge mixing ratio and moisture content of raw material are both 15%.