摘要：

以模拟产酸发酵液为对象，采用减压蒸馏法提取其中高价值的挥发性有机酸（VFAs），探讨了蒸馏温度、初始浓度对乙酸、丙酸和丁酸回收率的影响。结果表明，单一酸与混合酸模拟发酵液的回收规律呈现出一致性。减压蒸馏出液量主要受蒸馏温度控制，有机酸回收率受初始浓度和温度的双重影响，回收率随温度和初始浓度升高而升高。相同蒸馏条件下，乙酸、丙酸和丁酸回收率差异显著，表现为丁酸>丙酸>乙酸，此排序不受原始酸浓度影响，碳链长度是主导因素。针对混合酸模拟发酵液，通过Spearman相关性分析进一步揭示，温度是影响各酸回收率的关键因素，但不同酸的主导影响因素各异，乙酸回收率主要受原始乙酸、丙酸、丁酸浓度影响；丙酸回收率与原始丁酸浓度相关，而丁酸回收率受乙酸和丙酸的影响较小。尽管减压蒸馏工艺分离有机酸效率较高，但其单位产品碳排放量偏高。该工艺具有较大碳减排空间，可通过设备升级改造、优化生产工艺、与其他产热工艺组合等方式，回收废热，降低用电量，从而实现碳减排目标。

关键词: 模拟发酵液, 减压蒸馏, 挥发性有机酸, 回收率, 碳排放

Abstract:

High-value volatile fatty acids(VFAs) were extracted from the simulated acid-producing fermentation broth by vacuum distillation method. The effects of distillation temperature and initial acid concentration on the recovery rates of acetic acid, propionic acid and butyric acid were studied. The results showed that the recovery patterns of single-acid and mixed-acid simulated fermentation broths showed consistency. The amount of vacuum distillation liquid was mainly controlled by distillation temperature, and the acid recovery rate was affected by both initial concentration and temperature. The recovery rate increased with the increase of temperature and initial concentration. There was a significant difference in the recovery rates of acetic acid, propionic acid and butyric acid, manifested as butyric acid>propionic acid>acetic acid. This ranking was not affected by the initial concentration, and the length of the carbon chain was the dominant factor. For the mixed-acid simulated fermentation broth, Spearman correlation analysis showed that temperature was the main factor affecting the recovery rate of three acids, but the affecting factors varied for the three acids. The main factors affecting the recovery rate of acetic acid extraction were the concentration of original acetic acid, propionic acid, and butyric acid. The factors affecting the recovery rate of propionic acid extraction included the original concentration of butyric acid, while the recovery rate of butyric acid was less affected by acetic acid and propionic acid. Although the vacuum distillation process exhibited high efficiency in separating organic acids, its carbon emissions per unit of product were relatively high. However, the waste heat could be recovered and utilized by upgrading the equipment, optimizing the production process and combining with other heat-generating processes, so as to reduce the electricity consumption of vacuum distillation and achieve carbon emission reduction.

Key words: simulated anaerobic fermentation, vacuum distillation, volatile fatty acids, recovery rate, carbon emission

中图分类号: 

• X703