CO_(2)溶解石灰石的淡化水矿化试验研究

Experimental study on mineralization of desalinated water by CO_(2)dissolve limestone

针对海水淡化后处理CO_(2)溶解石灰石工艺设计冗余、工程调试缺乏依据等问题,在溶解模型基础上,以常用3~5mm粒径和10~12mm粒径石灰石为研究对象,开展了不同流速下气水比对矿化后硬度、pH、反应速率影响的试验,并对两种粒径石灰石溶解过程进行对比分析。试验结果显示,石灰石溶解是一个缓慢过程,反应速率仅为10^(-5)~10^(-4)mmol/(cm^(2)·s)量级,当反应到达平衡后硬度、反应速率等不再继续增加。根据试验结果,提出石灰石粒径为3~5mm具有经济性,且气水比在6%以下时,反应受流速影响小,硬度最大可达148mg/L,并核算产水硬度为50~100mg/L的后处理工艺药剂消耗仅为0.07~0.17元/m^(3)。

Aiming at the problems of redundant design and lack of basis for engineering commissioning of CO_(2)dissolving limestone process of seawater desalination post-treatment,the test takes the limestone with particle size of 3~5 mm and 10~12 mm as the research object,carries out the influence of gas-water ratio in desalted water on hardness,pH and reaction rate by different flow rates,and the dissolution process of limestone with two particle sizes is compared and analyzed.The test results shows that dissolution of limestone is a slow process with the reaction rate only 10^(-5)~10^(-4)mmol/(cm^(2)·s),and when the reaction reaches the equilibrium concentration,the hardness and reaction rate will no longer increase.According to the test results,the suitable gas-water ratio range for post-treatment engineering application is less than 6%,which is less affected by the flow rate,and the maximum hardness can reach 148 mg/L.According to the calcula-tion,the reagent consumption per ton of water with a water production hardness of 50~100 mg/L in the post-treatment process is only 0.07~0.17 yuan/m^(2).