柑橘皮渣厌氧发酵的碱热预处理优化研究

EFFECT OF THERMAL ALKALINE PRETREATMENT ON ANAEROBIC DIGESTION OF CITRUS PROCEESING WASTE

采用不同碱热预处理条件对柑橘皮渣进行预处理,研究对底物水解和高温厌氧发酵的促进作用。实验发现,碱热预处理柑橘皮6h比预处理12和24h更为经济可行;NaOH浓度为5.0%和7.5%处理柑橘皮6h,分别得到最高的乙醇和乙酸含量,70℃、NaOH浓度7.5%预处理后厌氧发酵得到最高产甲烷潜力为274.2mL/g VS,较对照提高20.1%;而将柑橘榨汁渣在70℃、pH值11的条件下预处理6h后厌氧发酵,得到最大的产甲烷潜力258.7mL/g VS,较对照提高39.9%,预处理后pH值为7.03,可直接用于厌氧发酵,具有实际应用的价值。

Using the citrus processing waste（citrus peel wste,citrus pressing waste）as the substrate of anaerobicdigestion is a promising alternative to the reuse of citrus processing waste.And the thermal alkaline pretreatmentcould increase the p H of the substrate,the biodegradability of cellulose materials,and the production of methane.The s CODs are decreased when the duration of pretreatment of citrus peel waste（CPW1）are increased from 6 h to24 h.The duration of 6 h is found to be the most economical one,because of the less energy input,although the VSdegradation rates are slightly lower at the NaOH loading rate of 5.0% and 7.5%（g NaOH/g VS）.And at the NaOHloading rate of 5.0% and 7.5%,the highest ethanol and acetic acid are produced after the pretreatment of CPW1 for6 h.At 70 ℃ and NaOH loading rate of 7.5%（p H 11.06±0.04）,the cumulative methane production is 274.2 m L/g VS,which is the highest and 20.1% higher in comparison with the untreated CPW1.The thermal alkaline pretreatmentcould also improve the anaerobic digestion of citrus pressing waste（CPW2）.And the highest cumulative methaneproduction is the pretreatment at 70 ℃,p H 11,which obtains 258.7 m L/g VS,and it is 39.9% higher than theuntreated CPW2.And the p H is 7.03 after pretreatement,so it is recommended as the optimum pretreatmentcondition of CPW2,because of the highest methane production and the less chemical use.