Chemical Reaction Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden; School of Engineering, University of Borås, 501 90 Borås, Sweden.
Bioresour Technol. 2010 Jun;101(11):4246-50. doi: 10.1016/j.biortech.2010.01.077. Epub 2010 Feb 9.
Production of ethanol, biogas, pectin and limonene from citrus wastes (CWs) by an integrated process was investigated. CWs were hydrolyzed by dilute-acid process in a pilot plant reactor equipped with an explosive drainage. Hydrolysis variables including temperature and residence time were optimized by applying a central composite rotatable experimental design (CCRD). The best sugar yield (0.41g/g of the total dry CWs) was obtained by dilute-acid hydrolysis at 150 degrees C and 6min residence time. At this condition, high solubilization of pectin present in the CWs was obtained, and 77.6% of total pectin content of CWs could be recovered by solvent recovery. Degree of esterification and ash content of produced pectin were 63.7% and 4.23%, respectively. In addition, the limonene of the CWs was effectively removed through flashing of the hydrolyzates into an expansion tank. The sugars present in the hydrolyzates were converted to ethanol using baker's yeast, while an ethanol yield of 0.43g/g of the fermentable sugars was obtained. Then, the stillage and the remaining solid materials of the hydrolyzed CWs were anaerobically digested to obtain biogas. In summary, one ton of CWs with 20% dry weight resulted in 39.64l ethanol, 45m(3) methane, 8.9l limonene, and 38.8kg pectin.
从柑橘废物（CWs）中通过综合工艺生产乙醇、沼气、果胶和柠檬烯。在配备爆炸排水装置的中试工厂反应器中，通过稀酸法水解 CWs。通过应用中心复合旋转实验设计（CCRD）优化水解变量，包括温度和停留时间。在 150 摄氏度和 6 分钟停留时间的稀酸水解条件下，获得了最佳的糖产量（0.41g/g 总干 CWs）。在此条件下，CWs 中存在的果胶高度溶解，CWs 中总果胶含量的 77.6%可通过溶剂回收得到回收。果胶的酯化度和灰分含量分别为 63.7%和 4.23%。此外，通过将水解产物闪蒸到膨胀罐中，有效地去除了 CWs 中的柠檬烯。水解物中的糖转化为乙醇，使用面包酵母获得 0.43g/g 的发酵糖产率。然后，将水解后的 CWs 的酒糟和剩余固体物料进行厌氧消化以获得沼气。总之，每吨干重 20%的 CWs 可产生 39.64l 乙醇、45m(3)甲烷、8.9l 柠檬烯和 38.8kg 果胶。
