焦化固废的锅炉协同处理技术实现了热量资源化回收，为评估该工艺的环境危害，在某480 t/h 煤粉锅炉上进行原煤、生化污泥和焦油煤粉共燃烧试验，对锅炉排放的烟气、炉渣、飞灰和硫酸铵等样品进行采样分析，研究掺烧工况下多种污染物的排放特征及其对环境的影响。结果表明，在煤、生化污泥和焦油煤粉掺烧比为100.0∶3.0∶1.5的协同工况下，炉内燃烧稳定，各运行参数波动小。16种多环芳烃(PAHs)中，以低环(2～3环)PAHs的萘和苊烯为主，其他PAHs类物质的质量浓度均较低，烟气中PAHs总质量浓度为71.3 ng/m3，固体样品中PAHs质量分数均低于0.5 mg/kg；烟气中二噁英类质量浓度为0.004 3 ng/m3，相较空白工况下降61.3%，固体样品中二噁英类质量分数均低于2.0 ng/kg；掺烧工况下各有机物排放均符合标准。生化污泥中Cr质量比是原煤的3.6倍, As是原煤的26倍，导致混合燃料中重金属Cr、As的质量比分别增加了21.1%、63.1%，其他重金属元素无明显增加。90%以上的Cr和As 赋存于飞灰中，2%～4%存在于炉渣中，仅有极少部分存在于烟气和硫酸铵中。烟气中Cr质量浓度为6.69 μg/m3，相较空白工况下降45.2%，烟气中As质量浓度降至低于检出限。炉渣、飞灰和硫酸铵等固体样品的浸出试验表明，Cr、As浸出质量浓度分别低于4.0和0.1 mg/L，重金属浸出无环境风险。试验过程污染物排放浓度均低于我国现行标准限值，锅炉协同处理技术环境风险可控，为焦化固废的无害化利用提供参考。

The boiler collaborative treatment technology of coking solid waste realizes the heat resource recovery. The CO combustion test of raw coal, biochemical sludge and tar pulverized coal was carried out on a 480 t/h pulverized coal boiler to evaluate the environmental harm of the collaborative utilization of coking solid waste. The flue gas, slag, fly ash and ammonium sulfate were sampled and analyzed to study the emission characteristics of various pollutants and their impact on the environment under the mixed combustion condition. The results show that the combustion is stable and the fluctuation of various operating parameters is small when the mixing ratio of coal, biochemical sludge and tar pulverized coal is 100.0∶3.0∶1.5. Naphthalene and acenaphthylene in low ring (2-3 ring) polycyclic aromatic hydrocarbons are the main components of 16 PAHs, and the monomer contents of other PAHs are low. The total toxic equivalent concentration of PAHs in flue gas is 71.3 ng/m3, and the concentration of PAHs in solid samples is lower than 0.5 mg/kg. The concentration of dioxins in flue gas is 0.004 3 ng/m3, which is 61.3% lower than that in blank condition. The concentration of dioxins in solid samples are lower than 2.0 ng/kg. All organic matter emissions under collaborative working condition meet the standards. The mass ratio of Cr and As in biochemical sludge are 3.6 and 26 times of that in raw coal, resulting in the mass ratio of Cr and As in mixed fuel increased by 21.1% and 63.1%, respectively, and other heavy metals do not increase significantly. More than 90% of Cr and As exist in fly ash, about 2%-4% in slag, and only a small part in flue gas and ammonium sulfate. The Cr content in flue gas is 6.69 μg/m3, which decreases by 45.2% compared with blank condition, and the As content is below the detection limit. The leaching experiment of solid samples such as slag, fly ash and ammonium sulfate show that the leaching mass concentrations of Cr and As in solid samples are lower than 4 mg/L and 0.1 mg/L, respectively and there is no environmental risk in the leaching of heavy metals. The emission concentrations of pollutants in the test process are lower than the current standard limit in China, and the environmental risk of boiler collaborative treatment technology is controllable, which provides a reference for the harmless utilization of coking solid waste.

0 引言

1 试验

   1.1 试验方法

   1.2 燃料理化特性

   1.3 试验测试方法

2 结果与讨论 

   2.1 协同处理对锅炉运行的影响

   2.2 协同处理对有机污染物排放影响

   2.3 协同处理对重金属排放影响

3 结论