Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden; Industrial Doctoral School, Umeå University, SE-901 87 Umeå, Sweden.
Energy Engineering, Department of Engineering Sciences & Mathematics, Luleå University of Technology, SE-971 87 Luleå, Sweden; Thermochemical Energy Conversion Laboratory (TEC-Lab), Department of Applied Physics and Electronics, Umeå University, SE-901 87 Umeå, Sweden.
Waste Manag. 2017 Oct;68:646-652. doi: 10.1016/j.wasman.2017.06.017. Epub 2017 Jun 17.
Torrefaction of municipal solid waste (MSW), refuse-derived fuel (RDF), and demolition and construction wood (DC) was performed at 220°C and a residence time of 90min in a bench-scale reactor. The levels of toxic polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) contained in emission from the torrefaction process were evaluated. In addition, main ash-forming elements and trace metals in the raw feedstock and char were determined. The use of MSW in fuel blends with DC resulted in lower PCDD and PCDF emissions after torrefaction, compared with the RDF blends. The migration of chlorine from the feedstock to the gas phase reduces the chlorine content of the char which may reduce the risk of alkali chloride-corrosion in char combustion. However, trace metals catalytically active in the formation of PCDD and PCDF remain in the char, thereby may promote PCDD and PCDF formation during subsequent char combustion for energy recovery; this formation is less extensive than when the feedstock is used.
在实验室规模的反应器中,将城市固体废物(MSW)、垃圾衍生燃料(RDF)和拆除与建筑木材(DC)在 220°C 和 90min 的停留时间下进行热解。评估了热解过程排放物中所含的有毒多氯二苯并对二恶英(PCDD)和多氯二苯并呋喃(PCDF)的水平。此外,还测定了原始原料和炭中的主要灰分形成元素和痕量金属。与 RDF 混合物相比,将 MSW 与 DC 混合作为燃料混合物进行热解后,可降低 PCDD 和 PCDF 的排放。来自原料的氯向气相中的迁移降低了炭中的氯含量,这可能降低了在炭燃烧中碱金属氯化物腐蚀的风险。然而,在 PCDD 和 PCDF 的形成中具有催化活性的痕量金属仍残留在炭中,从而可能在随后的炭燃烧中促进 PCDD 和 PCDF 的形成以进行能量回收;这种形成的程度不如使用原料时广泛。