污泥脱水技术研究进展及碳排放比较分析

Comparative analysis of sludge dewatering technology from research progress and carbon emission

本文综述了几种常规污泥脱水技术(污泥浓缩、机械脱水和深度脱水)和几种新兴的污泥低能耗深度脱水技术(低温干化、生物干化和超临界CO_(2)脱水)的原理及特点,并重点对重力浓缩、机械脱水、预处理脱水、热干化、太阳能干化、热泵干化、生物干化、超临界CO_(2)脱水这几种技术进行了碳排放核算和对比分析.结果表明,常规脱水技术相对较为成熟,应用较广,但存在能耗高、药耗高、碳排放高的“三高”问题.其中,污泥热干化技术的碳排放量最大(2070.21kgCO_(2)/t DS),使用化学药剂产生的碳排放占机械脱水和预处理脱水技术碳排放的75%以上.新兴的太阳能干化、热泵干化、生物干化和超临界CO_(2)脱水技术的碳排放量分别为32.67,1074.36,58.78,490.16kgCO_(2)/t DS,表现出较好的碳减排潜力,通过推进优化工艺技术,降低运行成本,有望替代常规脱水技术.本研究结果可为污泥低碳脱水技术的开发和选择提供重要的参考依据.

In this study,the principles and characteristics of several conventional sludge dewatering technologies(sludge thickening,mechanical dewatering and deep dewatering),and several emerging deep dewatering technologies with low-energy(low-temperature drying,biological drying and supercritical CO_(2)dewatering),were reviewed.Meanwhile,the carbon emissions of different technologies were analyzed in comparison.The results showed that the conventional dewatering technology exhibited the advantages of relative maturity and wide application,but there were problems,such as high energy consumption,high chemicals consumption and high carbon emission,that is,"three high"problem.Among above technologies,the carbon emission from thermal drying technology was the most significant(2070.21kg CO_(2)/t DS),and more than 75%of carbon emissions were attributed to the use of chemicals in mechanical dewatering and pretreatment dewatering processes.Superior carbon reduction potential was showed in the emerging technologies,which were 32.67(solar drying),1074.36(heat pump drying),58.78(biological drying)and 490.16(supercritical CO_(2)dewatering)kg CO_(2)/t DS,respectively.They will be promising alternatives for conventional sludge dewatering technologies through optimization of process parameters and reduction of operating costs.The results of this study can provide important reference and foundation for the development and selection of low-carbon sludge dewatering technology.