A process model to estimate the cost of industrial scale biodiesel production from waste cooking oil by supercritical transesterification

This paper describes the conceptual design of a production process in which waste cooking oil is converted via supercritical transesterification with methanol to methyl esters (biodiesel).Since waste cooking oil contains water and free fatty acids, supercritical transesterification offers great advantage to eliminate the pre-treatment capital and operating cost.A supercritical transesterification process for biodiesel continuous production from waste cooking oil has been studied for three plant capacities (125,000; 80,000 and 8000 tonnes biodiesel/year). It can be concluded that biodiesel by supercritical transesterification can be scaled up resulting high purity of methyl esters (99.8%) and almost pure glycerol (96.4%) attained as by-product.The economic assessment of the biodiesel plant shows that biodiesel can be sold at US$ 0.17/l (125,000 tonnes/year), US$ 0.24/l (80,000 tonnes/year) and US$ 0.52/l for the smallest capacity (8000 tonnes/year).The sensitive key factors for the economic feasibility of the plant are: raw material price, plant capacity, glycerol price and capital cost.Overall conclusion is that the process can compete with the existing alkali and acid catalyzed processes.Especially for the conversion of waste cooking oil to biodiesel, the supercritical process is an interesting technical and economical alternative.     

Insights into process safety incidents from an analysis of CSB investigations

Many incidents have helped to define and develop process safety. Each has provided valuable learning opportunities. However, it is even more important to identify insights that can be obtained from an analysis of a large set of incidents that represents those that typically occur. This larger picture illuminates trends and commonalities and provides learning opportunities that are even more important than the causes of any one individual incident.The Chemical Safety Board has published the results of over 60 investigations of process safety incidents. These data have been analyzed to identify commonalities and trends so that measures to help protect against future incidents can be developed. Recommendations are made to address key issues identified.     

层次分析法在生态效率评价中的应用研究

生态效率作为循环经济发展水平的评价指标,对其进行客观性的评价十分重要。本文以无锡新区生态工业示范园区、苏州工业园区生态工业园和苏州高新区3个园区为例,提出了生态效率评价的层次分析法,在很大限度上避免了人为制定权重的主观性。同时,对3个园区的循环经济发展水平进行定量的对比。     

Fenton试剂处理实验室有机废水的试验研究

用Fenton试剂对实验室有机废水进行处理研究。考察了pH值、H2O2和硫酸亚铁的用量、反应时间等因素对废水降解过程的影响,确定了方法的优化奈件,并讨论了Fenton试剂的反应机理。实验结果表明：pH值在6．0,30％的H2O2用量为4．0mL,硫酸亚铁用量为1．5g．反应时间为30min时,处理效率最好。