含硝废硫酸常压处理工艺的模拟及优化

Simulation and optimization on normal pressure treatment process for nitrates-containing spend sulfuric acid

以石英精馏设备为基础,结合含硝废硫酸物性及分离要求,建立了含硝废硫酸脱硝-浓缩常压处理工艺,并采用Aspen软件完成工艺模拟。以理论板数、进料位置、回流比、塔顶采出量为自变量,以脱硝塔塔底物料硫酸质量分数及有机物质量分数、浓缩塔塔顶及塔底物料硫酸质量分数为因变量,完成脱硝塔和浓缩塔的灵敏度分析,优化了工艺设计运行参数。脱硝后的废酸中有机物质量分数小于100×10^(-6),可避免硫酸浓缩过程有机物结焦;浓缩最终得到98%浓硫酸,硫酸回收率超过99.9%,实现了硝化废硫酸的资源再利用。

According to the characteristics of nitrates-containing spend sulfuric acid and separation requirement,a normal pressure treatment process consisting of denitration and concentration based on quartz distillation equipment is developed for the treatment of nitrates-containing spend sulfuric acid.The process is simulated and optimized with Aspen Plus software.The sensitivity analysis for denitration tower and concentration tower is completed,and the process design operation parameters are optimized through taking the number of theoretical plates,feed position,reflux ratio,and top recovery as independent variables,and the mass fractions of sulfuric acid and organic matter at the bottom of denitration tower,and the mass fraction of sulfuric acid at the top and bottom of concentration tower as dependent variables.It is found that under the optimum process conditions,the coking phenomenon in concentration tower can be avoided if the organic content in the denitration tower bottom is below 100 ppm.After concentration,concentrated sulfuric acid with a purity of 98%is obtained,and the recovery rate of sulfuric acid exceeds 99.9%.