水热污泥与煤在混燃过程中的协同效应特性研究

以城市污泥衍生的水热污泥(SS-derived hydrochar)为对象,结合傅里叶红外光谱分析(FT-IR)、X射线荧光光谱分析(XRF)和X射线衍射分析(XRD)等对比研究了水热污泥与三种不同品阶煤(褐煤、烟煤和无烟煤)在有机/无机结构与燃料特性上的异同;同时,通过热重(TG)与偏差分析(Deviation)考察水热污泥与各阶煤在不同混合比例条件下的协同燃烧行为及其作用机制。结果表明,污泥经过水热处理后其有机结构和燃烧行为均提升至与煤相似的水平,该过程不仅改善污泥的燃烧特性,并增强其与煤之间的协同燃烧效应。水热污泥中适量的轻质组分与(碱)碱土金属能在混合燃烧过程中加速煤的失重速率,其对三种煤的促进作用可达4.4%-16.1%(褐煤)、1.9%-9.4%(烟煤)和4.8%-12.1%(无烟煤)。总体而言,水热污泥与褐煤混合而成的燃料在燃料性能上具有较大的优势,并且其混合比例以30%(水热污泥):70%(褐煤)与50%(水热污泥):50%(褐煤)为宜。

Synergistic effects in co-combusting of hydrochar derived from sewage sludge with different-rank coals

Differences on organic/inorganic structures and fuel properties between sewage sludge-derived hydrochar and different-rank coals were investigated and compared with the help of FT-IR, XRF and XRD technologies. Meanwhile, the combustion behavior under various blending ratio and its synergistic effects was identified via TG and deviation analysis. The results demonstrates that the organic structures and combustion behaviors of hydrochar are similar to those of coals, which not only improves the combustion properties of sewage sludge, but also enhances the synergistic effects in co-combustion of hydrochar and coals. During the co-combustion process, light volatiles and (alkaline) alkaline-earth metals in hydrochar could accelerate the weight loss rate for coals, reaching 4.4%-16.1%, 1.9%-9.4% and 4.8%-12.1% for lignite, bitumite and anthracite, respectively. In general, the blends with 30% hydrochar and 70% lignite or 50% hydrochar and 50% lignite are better than other blends in terms of comprehensive combustion evolutions.