Bio-Energy Research Team, Research Institute of Industrial Science and Technology (RIST) , 813-1 Keumho-Dong, Kwang-Yang-City Cholla-Nam-Do, South Korea, 545-090.
Environ Sci Technol. 2012 Sep 18;46(18):10222-8. doi: 10.1021/es3019435. Epub 2012 Aug 24.
This work demonstrates that the production of biodiesel using the lipids extracted from sewage sludge (SS) could be economically feasible because of the remarkably high yield of oil and low cost of this feedstock, as compared to conventional biodiesel feedstocks. The yield of oil from SS, 980,000 L ha(-1) year(-1), is superior to those from microalgal and soybean oils, 446 and 2200 L ha(-1) year(-1), respectively. According to the case study of South Korea, the price of the lipids extracted from SS was approximately $0.03 L(-1) (USD), which is lower than those of all current biodiesel feedstocks. This work also highlights the insight of a novel methodology for transforming lipids containing high amounts of free fatty acids (FFAs) to biodiesel using a thermochemical process under ambient pressure in a continuous flow system. This allowed the combination of esterification of FFAs and transesterification of triglycerides into a single noncatalytic process, which led to a 98.5% ± 0.5% conversion efficiency to FAME (fatty acid methyl ester) within 1 min in a temperature range of 350-500 °C. The new process for converting the lipids extracted from SS shows high potential to achieve a major breakthrough in minimizing the cost of biodiesel production owing to its simplicity and technical advantages, as well as environmental benefits.
本研究工作表明，与传统生物柴油原料相比，利用污水污泥（SS）提取的油脂生产生物柴油具有很高的产油率和低廉的原料成本，因此在经济上是可行的。SS 的产油率为 980,000 L ha(-1) year(-1)，优于微藻和大豆油的产油率，分别为 446 和 2200 L ha(-1) year(-1)。根据韩国的案例研究，从 SS 中提取的油脂的价格约为 0.03 美元/L(-1)，低于所有当前生物柴油原料的价格。本工作还强调了一种新颖的方法，即在环境压力下、连续流动系统中采用热化学工艺，将含有大量游离脂肪酸（FFAs）的油脂转化为生物柴油。这使得在 350-500°C 的温度范围内，FFA 的酯化和甘油三酯的酯交换可以在 1 分钟内转化为 98.5%±0.5%的脂肪酸甲酯（FAME），达到了单一非催化过程。这种从 SS 中提取的油脂的转化新工艺具有很高的潜力，可以实现生物柴油生产成本的重大突破，这归因于其简单的工艺和技术优势，以及环境效益。
