熔融结晶法浓缩稀硫酸

Concentrating dilute sulfuric acid by melt crystallization

提出了采用熔融结晶法浓缩稀硫酸的新工艺。以初始质量分数为5%的稀硫酸溶液为料液进行熔融结晶实验,在合适的操作条件下成功地将料液浓缩至23%以上,验证了熔融结晶法浓缩稀硫酸的可行性。建立熔融结晶动态过程的数学模型并取得了良好的拟合结果。考察并分析了熔融结晶过程的各操作条件对浓缩过程的影响。结果表明,低过热度、合适的进料速率、较高的降温速率对于提高浓缩效率和晶层生长速率有益。对熔融结晶浓缩过程和工业上常用的蒸发浓缩过程分别进行了耗能量计算,结果表明,在相同的稀硫酸浓缩程度下熔融结晶浓缩过程的耗能量仅占蒸发浓缩过程的60%左右。

The novel melt crystallization process for concentrating and recycling dilute sulfuric acid from industrial wastewater is proposed.Taking the dilute sulfuric acid solution with an initial mass concentration of 5 wt% as raw solution to carry out melt crystallization test,under proper operational conditions the concentration of raw solution is successfully concentrated to above 23 wt%,which proves the feasibility of using melt crystallization method to concentrate dilute sulfuric acid.The mathematical model is established for simulating melt crystallization dynamic process,by which good fitting results are obtained.The effects of operational conditions in melt crystallization process on the concentration process are inspected and analyzed.Results show that low degree of superheat,proper feeding rate and higher cooling speed can help to increase crystal layer growth rate and concentrating efficiency. Furthermore,the energy consumption of the melt crystallization process and the evaporate concentration process that is often used in industry are calculated respectively.Results indicate that the energy consumption of the melt crystallization process is equivalent to about 60% that of the evaporate concentration process under the same concentrating degree of dilute sulfuric acid.