路用改性煤沥青毒性消减试验效果分析

Analysis of toxicity reduction test about modified coal tar used for road

为将煤化工产业固体废弃物煤焦油沥青用于道路工程，对其进行改性，分析煤沥青中具有强致癌作用苯并芘的脱除机理．选择三聚甲醛及聚氨酯混合物作为脱除剂，使用紫外分光光度计测试其脱除率．结果表明，煤沥青中苯并芘的质量分数由2．85％降至0．40％，达到路用煤沥青施工安全要求．针对改性煤沥青热拌和过程中挥发大量的有毒烟气问题，采用气相色谱分析方法，鉴定和分析了改性煤沥青中的发烟物质，并针对其发烟物质，设计抑烟方案；根据煤沥青的分子结构，制备和煤沥青油端结构相似的水溶性表面活性剂、复合表面活性剂和发泡剂．通过验证发泡剂用量和发泡温度，确定了在膨胀率≥10、半衰期〉8S时的最佳拌合温度为105～110℃，发泡剂最佳添加质量分数为3．5％，该条件下可有效降低拌合温度，减少有毒烟气的挥发．

In order to use coal tar pitch, which is one of the solid wastes of the coal chemical industry, in road con- struction, we modify the material by removing the carcinogenic benzopyrene inside it. The mixture of trioxane and polyurethane is selected as scavengers, and the removal performance is evaluated by the UV spectrophotometer. The results show that the benzopyrene content in coal tar pitch decreases from 2. 85% to 0. 40% , which can satisfy the safety requirements of coal asphalt used for road construction. As for the large numbers of toxic fumes produced in the thermal-mixing process of coal tar pitch, we analyse the smoke material of the modified coal tar by gas chroma- tography analysis, and then propose a design of smoke suppression for fuming substance. Based on the molecular structure of the coal tar pitch, we design a water-soluble surfactant whose structure is similar to that of coal tar oil- terminal, the compound surfactant and the blowing agent. By testing the dosage of foaming agent and the foaming temperature, we find that the best mixing temperature should be in the range of 105 ℃ to 110 ℃ under the condition of the expansion ratio being greater than 10 and the half-life being greater than 8 s. In addition, the optimum dosage of blowing agent is 3.5% under this condition; the mixing temperature and evaporation of toxic fumes can be decreased effectively.