热脱附技术在某污染地块土壤修复工程中的应用

Application of Thermal Desorption Technology in Soil Remediation in a Pollution Site

江西某化工厂关闭搬迁后,经土壤污染状况调查及风险评估,地块内主要存在有机物污染,污染土壤采用“常温热解析+热脱附”技术处理。常温热解析采用生石灰对污染土壤进行脱水干燥处理,挥发性有机物挥发后气体抽气通过尾气处置装置处理;热脱附处理将污染土壤通过密闭输送带进入土壤料仓,逆向进入热脱附滚筒,通过逆向式热交换将污染土壤及其所含的有机污染物加热到300℃以上,停留时间约30 min,高温烟气在引风机作用下进入后续尾气处理系统,尾气均可达标排放,最终通过了省级生态环境保护主管部门组织的效果评估。实践证明,该地块内污染土壤采用“常温热解析+热脱附”技术处理是可行的。

After a chemical plant in Jiangxi Province was closed and relocated,after investigation of soil pollution and risk assessment,organic matter pollution was mainly present in the plot.The polluted soil was treated by"normal temperature thermal analysis+thermal desorption"technology.At room temperature,quicklime was used to dehydrate and dry the contaminated soil.After volatile organic compounds volatilized,the gas was pumped through the tail gas disposal device.The polluted soil is transported into the soil bin through closed conveyor belt by thermal desorption treatment,and then into the hot desorption drum in reverse direction.The polluted soil and its organic pollutants are heated to more than 300℃by reverse heat exchange,and the residence time is about 30 min.The high temperature flue gas is put into the subsequent tail gas treatment system under the action of induced draft fan,and the exhaust gas can be discharged up to standard,Finally,the evaluation of the effect organized by the provincial competent department of ecological and environmental protection was passed.The practice shows that the treatment of polluted soil in this plot is feasible by using the technology of"normal temperature thermal analysis+thermal desorption".