添加剂对燃料式熔炉固化垃圾焚烧飞灰特性的影响

The Effect of Additive on Solidification of MSWI Fly Ash by Fuel Furnace

采用燃料式表面熔炉,以废旧石英玻璃粉代替纯SiO2作为添加剂,对杭州某生活垃圾焚烧厂的焚烧飞灰,连续进行了6个多月、处理规模为500 kg/d的熔融固化中试分析,主要研究了添加剂对焚烧飞灰的熔融温度、重金属固定率、熔渣中重金属的浸出质量浓度、烟气中二英和其他污染物排放水平的影响,同时探讨了整个系统的稳定性和可操作性.结果表明:添加剂能有效降低飞灰的熔点,并使熔渣中重金属浸出质量浓度有所减少;同时也可显著提高重金属Cu和Zn的固定率,但对Pb,Cd和Cr的固定率影响不明显;当温度高于到达飞灰样品熔融温度时,所有飞灰样品的减容率均高于80%,飞灰样品的减容率依次为w(添加剂)为20%的飞灰>w(添加剂)为10%的飞灰>w(添加剂)为5%的飞灰>原灰.二英总毒性当量浓度(以TEQ计)为0.053 ng/m3,远低于国家标准.同时发现在一定运行条件下,排放烟气中其他污染物的排放浓度均符合国家相关标准,且运行期间系统稳定、可操作性强.

The experiments were carried out to test the additive （glass dust as a substitute for SiO2 ） on the melting and solidification condition of fly ash from municipal solid waste incinerator （MSWI） for more than 6 months with a total daily treatment capacity of 500 kilograms by diesel oil furnace in a pilot scale, intending to clarify the effects of the additive on the melting temperature, volume reduction and the concentration of leaehing heavy metals in molten slag. The results show that the additive can effectively reduce the melting temperature of fly ash, and the remaining levels of heavy metals in molten slag that meets the standard limit of Toxicity Characteristic Leaching Procedure of United States. The additive addition can increase the fixed rate of Cu and Zn remarkably, but almost have not effects on the fixed rates of Pb, Cd and Cr. When the temperature reaches melting point of fly ash samples, the volume reduction rate of all fly ash samples is over 80%, with the order as follows： fly ash with 20% additive 〉 fly ash with 10% additive 〉 fly ash with 5% additive 〉 original fly ash. The total toxic levels of dioxin in flue gas is 0.053 ng-TEQ/m^3 , which is apparently lower than the national management guideline of total dioxin emissions, and the other pollutants in flue gas meet the national emissions. The whole molten system runs stably and is maneuverable to operate in the experimental periods.