双极膜电解提溴吸收完成液制备HBr和NaOH

Preparation of HBr and NaOH by Bipolar Membrane Electrolysis from Absorbed Complete Fluid of Bromine Extraction

采用双极膜电渗析(BMED)技术,对以提溴吸收完成液为原料电解制备NaOH和HBr的过程进行了研究。系统考察了电流强度、原料液初始质量浓度以及酸碱浓度等对实验的影响,以及在盐室的NaBr溶液中加酸的实验效果,用来模拟以甲酸钠溶液为吸收液的提溴吸收完成液。结果表明:适当提高膜堆的直流电强度有利于产酸产碱,但是电流效率更低,能耗更高,综合考虑,实验采用的电流强度为2.5～3.0 A。当原料液NaBr的初始质量浓度为40～50 g/L以及酸碱初始浓度为0.1～0.2 mol/L时,电流效率较高,能耗较低。随着酸碱初始浓度增加,电流效率和能耗的变化变小。在NaBr原料液中加酸会抑制碱的产生,相反产酸量则会大大提高。

Bromine is an important basic chemical raw material.The traditional process of bromine extraction needs to absorb the free bromine monomer into the absorbed complete solution.Then,through distillation,condensation,washing and other steps,the refine bromine can be achieved.However,the steps are tedious,and a large number of stream and condensated water are needed.Also,the energy consumption of this method is great,and the equipment scale of occupying is large.Therefore,in this paper a new idea with the short process and high added value utilization in the process of bromine extraction,comes up with a new way to produce HBr.The bipolar membrane electrolysis(BMED)technology was used to prepare NaOH and HBr with NaBr as the raw material.The effects of the current intensity,the initial mass concentration of NaBr,and the initial concentrations of NaOH and HBr in acid chamber were studied.The effect of acid in raw material was also investigated.The results show that increasing the direct-current(DC)intensity of the membrane stack is beneficial to the production of acid and alkali.However,compared to operation at the low current intensity,the current efficiency is lower,and the energy consumption is higher.The suitable current intensity is 2.5~ 3.0 A.When the initial mass concentration of NaBr is in the range of 40~50 g/L and the initial concentrations of acid and base is in the range of 0.1~ 0.2 mol/L,a low energy consumption and a high current efficiency are achieved.Both the current efficiency and energy consumption decrease with the increase of the initial concentrations of acid and alkali.The introduction of acid in the raw material inhibits the alkali production,while it facilitates acid production greatly.