Department of Civil Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do, 561-756, South Korea.
Chemosphere. 2013 Jan;90(4):1508-13. doi: 10.1016/j.chemosphere.2012.07.062. Epub 2012 Sep 25.
This work showed that sewage sludge could be a strong candidate for biodiesel production. High lipid content (18-20%) with C(16-18)-carbon range was experimentally identified and measured. These lipids from sewage sludge were converted into biodiesel via the transesterification reaction with MgO-CaO/Al(2)O(3) derived from magnesium slag, and biodiesel conversion was ~98%. The experimental work enabled explaining that temperature is the main driving force for the transesterification reaction, which can be enhanced in the presence of CO(2). This also enables combination of esterification of free fatty acids and transesterification of triglycerides into a single process within 1 min in the temperature range of 350-500°C. Sewage sludge residue after extracting lipids was also a good feedstock for recovering energy via thermo-chemical processes. The impact of CO(2) co-feed on the pyrolysis/gasification process of SS residue was also investigated in this work. The CO(2) injected into the thermo-chemical process remarkably increased the generation of CO by a factor of 2. Moreover, the introduction of CO(2) into the pyrolysis/gasification process enabled reducing condensable hydrocarbons (tar) by expediting cracking; thus, utilizing CO(2) as chemical feedstock for the gasification process not only leads to higher thermal efficiency but also has environmental benefits.
本研究表明，污水污泥是生物柴油生产的理想原料。实验鉴定并测量了高含量（18-20%）的 C（16-18）-碳范围的脂质。这些来自污水污泥的脂质通过与镁渣衍生的 MgO-CaO/Al(2)O(3)的酯交换反应转化为生物柴油，生物柴油转化率约为 98%。实验工作解释了温度是酯交换反应的主要驱动力，在 CO(2)存在下可以增强反应。这也使得游离脂肪酸的酯化和甘油三酯的酯交换可以在 350-500°C 的温度范围内在 1 分钟内结合成一个单一的过程。提取脂质后的污水污泥残渣也是通过热化学过程回收能源的良好原料。本研究还考察了 CO(2)共进料对 SS 残渣热解/气化过程的影响。注入热化学过程的 CO(2)显著提高了 CO 的生成量，增加了 2 倍。此外，将 CO(2)引入热解/气化过程可以通过加速裂解减少可冷凝烃（焦油），因此，将 CO(2)用作气化过程的化学原料不仅可以提高热效率，而且具有环境效益。
