Research and development of a sub-critical methanol alcoholysis process for producing biodiesel using waste oils and fats

• Published in: Chinese journal of catalysis Vol. 34; no. 1; pp. 101 - 115
• Main Authors: DU, Zexue, TANG, Zhong, WANG, Haijing, ZENG, Jianli, CHEN, Yanfeng, MIN, Enze
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2013
• Subjects: Biodiesel; Esterification; Methanol; Sub-critical methanol alcoholysis; Transesterification; Waste oils and fats; China, People's Rep; Transesterification; Waste oils and fats; Biodiesel; Sub-critical methanol alcoholysis; Esterification; Methanol
• ISSN: 1872-2067; 0253-9837; 1872-2067
• DOI: 10.1016/S1872-2067(11)60490-7

Waste oils and fats (WOFs) are non-edible oils generated in amounts of more than 30 million and 10 million tons/year in China, respectively, from the production and consumption of cooking oil, and which would pollute the environment if disposed of improperly. Due to its poor quality, it is very difficult to transform WOFs to biodiesel by base catalyzed transesterification, especially when these have high free fatty acids and impurities. A new technology, sub-critical methanol alcoholysis process (SRCA process), was developed by SINOPEC Research Institute of Petroleum Processing for producing biodiesel from WOFs. The technical problems that were solved included how to dissolve WOFs in methanol, how to moderate the reaction conditions, how to transform WOFs into more biodiesel, and how to improve product quality. The first industrial demonstration unit of SRCA process with a scale of 60 kton/year biodiesel was set up in 2009, and it had been operated continuously to produce biodiesel from soybean acid oil, palm acid oil, and cooking oil. The biodiesel product quality fulfil the requirements of National Standard (GB/T 20828-2007). 针对废弃油脂品质差, 酸值高, 难于采用传统的碱催化酯交换技术加工生产生物柴油, 中国石化石油化工科学研究院开展了超/近临界甲醇介质中油脂溶解和反应的基础研究, 相继解决了甲醇与油脂的互溶、降低反应条件, 三脂肪酸甘油酯和游离脂肪酸的深度转化, 以及产品质量等问题, 成功开发了近临界醇解生物柴油技术 (以下简称 SRCA), 于 2009 年建成了 6 万吨/年工业化示范装置, 以酸化油和餐厨废油为原料, 生产连续稳定, 产品收率高且满足国家生物柴油质量标准 (GB/T 20828-2007). The presence of water in the sub-critical methanol method catalyzed the alcoholysis reaction of triglycerides, which reduces significantly the severity of the reaction conditions, such as temperature, pressure, and methanol to oil molar ratio.