基于危险废物填埋新形势下焚烧产生飞灰处置技术研究

Research on Disposal Technology of Fly Ash Generated from Incineration Under the New Situation of Hazardous Waste Landfill

固体废物焚烧产生的飞灰属于危险废物,其中富含水溶性盐,而在新的《危险废物填埋污染控制标准》(GB 18598—2019)实施后,危险废物水溶性盐含量要求在10%以下,否则要进入刚性填埋场进行填埋,大大的增加了固体废物焚烧处置的成本。因此,以焚烧飞灰为研究对象,通过单因素实验分析了水固比、搅拌时间、搅拌温度、搅拌速率对飞灰水洗中可溶性盐溶出的影响。通过优化飞灰的水洗工艺,建立水洗参数与飞灰水洗后滤饼的水溶性盐含量的关系。结果表明,当水固比为4∶1(mL∶g)、水洗搅拌时间为3 min、搅拌温度为30℃、搅拌速率为1200 r/min时,滤饼中的水溶性盐含量降低最为明显,为3.98%,可以进入柔性填埋场安全填埋。同时,飞灰经一级水洗后的质量和体积分别减少了约为52.48%和33.85%,明显达到了降本增效的目的。水洗液可经资源化利用后进入三效蒸发进行水盐分离,盐分进入刚性填埋场处置。

Fly ash from solid waste incineration belongs to hazardous waste,which is rich in water-soluble salts.However,after the implementation of the new[WT5"BX]Standard for pollution control on the hazardous waste landfill(GB18598-2019),the content of water-soluble salt in hazardous waste is required to be less than 10%,otherwise it will enter the rigid landfill for landfill,which greatly increases the cost of solid waste incineration.Therefore,taking incineration fly ash as the research object,the effects of water/solid ratio,mixing time,mixing temperature and mixing rate on soluble salt dissolution in fly ash water washing were analyzed through single factor experiments.By optimizing the water washing process of fly ash,the relationship between the water washing parameters and the water soluble salt content of the filter cake after the fly ash water washing is established.The results showed that when the ratio of water to solid was 4∶1(mL∶g),the mixing time of water washing was 3 min,the mixing temperature was 30℃,and the mixing rate was 1200 r/min,the content of water-soluble salt in the filter cake decreased the most significantly,which was 3.98%,and it could enter the flexible landfill for safe landfill.At the same time,the mass and volume of fly ash after primary water washing decreased by about 52.48%and 33.85%respectively,obviously achieving the goal of reducing cost and increasing efficiency.The water washing liquid can be recycled and then enter the three-effect evaporation for water and salt separation,and the salt will be disposed in the rigid landfill.