循环流化床锅炉掺烧危废渣蜡对灰渣污染特征的影响

煤制油技术产生的易蓄热自燃的渣蜡属于危险废物，处置不当会带来较大的环境影响和环境风险。通过与燃料煤混合燃烧的利用方式处理渣蜡可降低处理成本，同时减少能源浪费。按燃料煤与渣蜡30∶1的比例混合，通过循环流化床 (CFB) 锅炉掺烧，对其热能进行利用，并研究其对CFB锅炉运行和灰渣特征的影响。结果表明，混合后的掺烧燃料组分变化差异较大，部分重金属含量有所增高；掺烧实验开始阶段锅炉的运行负荷和炉膛的出口温度出现明显上升，而工况稳定后，波动不大；相比燃料煤，掺烧产生的粉煤灰和炉渣的热灼减率无明显差异，二恶英类持久性有机污染物贡献均以OCDD为主导，但重金属铬、锰和铜含量稍有增加，主要受渣蜡中重金属迁移和难挥发影响。本研究结果可为通过循环流化床 (CFB) 锅炉掺烧发电的方式对渣蜡进行合理的资源化利用提供参考。

Influence of wax residue co-combustion in circulating fluidized bed boiler on the characteristics of fly ash and slag

The wax residual produced by coal-to-oil technology, which could induce heat accumulation and spontaneous combustion easily, is a kind of hazardous waste. Its improper disposal will bring about great environmental impacts and risks. The utilization of wax residue by co-combustion with fuel coal can reduce the disposal cost as well as energy waste. This study investigated the influences of wax residue co-combustion on the operation of the circulating fluidized bed (CFB) and the characteristics of fly ash and slag by co-combusting the fuel coal and the residual wax at the ratio of 30:1 in CFB to recover the thermal energy. The results showed that the mixed fuels varied widely in components, with some increased in heavy metals contents. The load of the boiler and the temperature at the furnace outlet experienced an obvious increase at the beginning of the co-combustion, while no significant fluctuations under stable working conditions. Compared with the fuel coal, there was no significant differences in the loss of ignition of the fly ash and slag in the co-combustion scenario. The contribution of dioxin-like POPs were dominated by OCDD in both scenarios. However, due to the migration and difficult volatilization of heavy metals in wax residue, the contents of chromium, manganese and copper were slightly increased in the co-combustion scenario. The results of this study can provide a theoretical reference for the feasible resource utilization of wax residue by means of CFB boiler co-combustion for power generation.