常减压工艺提取厌氧发酵液中挥发性有机酸的影响因素探析OA

In order to explore the separation characteristics of volatile organic acids(VFAs)in anaerobic fermentation broth,the acid-producing fermentation broth of food waste was taken as the experimental object.Atmospheric distillation and vacuum distillation were used to carry out organic acid separation and extraction experiments.The effects of distillation tem-perature and pH value on the separation and extraction efficiency of VFAs were systematically studied.The results showed that the pH value had a significant influence on the extraction efficiency of VFAs during atmospheric/vacuum distillation of anaerobic fermentation broth.The concentration of volatile fatty acids(VFAs)in the distillate decreases with an increase in pH for both atmospheric distillation and reduced-pressure distillation.When the pH value was in the acidic range of 1～3,the atmospheric distillation and vacuum distillation method were effective in extracting VFAs.At pH value 1,the total con-centration of VFAs is the highest,Under atmospheric and vacuum distillation,the total concentrations of VFAs were meas-ured at 31682.69 mg·L-1 and 26661.60 mg·L-1 respectively.In addition,during the distillation process,there was a cer-tain degree of loss of acetic acid,propionic acid,and butyric acid.Under the same pH conditions,The loss rate in atmos-pheric distillation is significantly higher than in vacuum distillation.Furthermore,Kendalls correlation analysis showed that there was a negative correlation between pH and the concentrations of acetic acid,propionic acid and butyric acid effluents,while there was no significant correlation between temperature and the concentrations of these effluents.Temperature was a key factor regulating the extraction rate of VFAs.