污泥与褐煤共水热碳化的协同特性研究

Investigation on synergistic characteristics of sludge and lignite during co-hydrothermal carbonization

污泥的资源化利用一直是国内外学者研究的焦点,对其进行水热提质处理后作为燃料应用是一种潜在的利用手段。本研究主要探讨城市污泥(SS)、脱墨污泥(DS)分别与褐煤(LC)以不同混合比例(3∶7、5∶5、7∶3)共水热碳化时的协同作用,并分析其固相产物(水热炭)的燃料品质。结果表明,当LC/SS、LC/DS混合比例为5∶5时,水热炭产率分别为81.08%和86.00%,并获得了最大协同系数(水热炭产率:1.69%和0.18%;有机物保留率:11.90%和2.64%;碳保留率:4.08%和0.77%)。其中,LC/SS的协同作用总是比LC/DS显著。随着LC添加量的增大,水热炭的热值和煤化程度均随之提高,不仅改善了水热炭的燃料特性,还使得燃烧过程更为稳定且充分。由此说明,通过共水热碳化预处理的方式可以制得较高品质的燃料,从而实现污泥/褐煤的有效利用。

The resource utilization of sludge has always been the focus of research by scholars. And their conversion into high quality solid fuels(hydrochars) via hydrothermal carbonization(HTC) is proved to be a promising potential technology. In this work, Co-HTC of sludge(sewage sludge, SS;deinking sludge, DS) and lignite(LC) was investigated to obtain a better preparation technology of sludge-derived hydrochars. The synergetic effect of mixing ratio(3∶ 7, 5∶ 5, 7∶ 3) on the HTC upgrading of sludge/LC mixtures was explored. And the combustion performance of hydrochars was also analyzed. The results have demonstrated that sludge/LC mixtures at a mixing ratio of 5∶5 have exhibited an optimal performance of hydrochar products. Specifically, the hydrochar yields can reach up to 81.08% and 86.00% for LC/SS and LC/DS, respectively. And high synergistic coefficients are observed in hydrochar yield(LC/SS-1.69%, LC/DS-0.18%), organics retention(LC/SS-11.90%, LC/DS-2.64%) and carbon retention(LC/SS-4.08%, LC/DS-0.77%), indicating a more remarkable synergetic effect of LC/SS than LC/DS.Besides, the higher heating value(HHV) and coalification degree of hydrochars can be enhanced by the increasing proportion of LC, which not only improves the fuel characteristics of hydrochars, but also makes it more stable and sufficient in the combustion process. These findings indicate that higher quality fuels can be obtained by Co-HTC pretreatment, thereby realizing the effective utilization of sludge/lignite.