双极膜电渗析清洁制备L-苹果酸过程工艺优化

Process optimization of clean preparation of L-malic acid by bipolar membrane electrodialysis

生产L-苹果酸的传统工艺多用钙盐法,需向发酵液投加大量无机酸,酸化过程产生大量废盐,导致额外的环境处置成本.本文提出两隔室型双极膜电渗析(BMED)法制备L-苹果酸的新型工艺,以转化率、电流效率及能耗等为评价指标,研究了电流密度、初始盐浓度、膜面流速等工艺参数对产酸性能的影响规律,优化了操作条件并进行了经济性分析.结果表明,对于模拟L-苹果酸二钠发酵液,控制电流密度为40 mA/cm^(2)、初始L-苹果酸浓度为0.2 mol/L、膜面流速为1.44 cm/s时,L-苹果酸的转化率可达94.99%,能耗为6.77 kWh/kg L-苹果酸,经济性分析显示其生产费用为11.34￥/kg L-苹果酸.研究可为L-苹果酸清洁制备工艺的开发、推进BMED在有机酸生产的应用提供有益参考.

The traditional process production of L-malic acid often uses calcium salt method,which requires adding a large amount of inorganic acid to the fermentation broth.The acidification process produces a large amount of waste salt,resulting in additional environmental disposal costs.This article proposes a new process for the preparation of L-malic acid using a two-compartment bipolar membrane electrodialysis(BMED).The conversion rate,current efficiency,and energy consumption are used as evaluation indicators.The influence of process parameters such as current density,initial salt concentration,and membrane surface flow rate on acid production performance was studied,and the operating conditions were optimized and economic analysis was conducted.The results showed that for simulating the fermentation broth of L-malic acid disodium,with a current density of 40 mA/cm^(2),an initial L-malic acid concentration of 0.2 mol/L,and a membrane flow rate of 1.44 cm/s,the conversion rate of L-malic acid could reach 94.99%,and the energy consumption was 6.77 kWh/kg L-malic acid.Economic analysis showed that the production cost was 11.34￥/kg L-malic acid.Research can provide useful references for the development of clean preparation processes for L-malic acid and the promotion of the application of BMED in organic acid production.