Utilization of waste freshwater mussel shell as an economic catalyst for biodiesel production

An economic and environmentally friendly catalyst derived from waste freshwater mussel shell (FMS) was prepared by a calcination-impregnation-activation method, and it was applied in transesterification of Chinese tallow oil. The as-prepared catalyst exhibits a “honeycomb” -like structure with a specific surface area of 23.2 m² g⁻¹. The newly formed CaO crystals are major active phase of the catalyst. The optimal calcination and activity temperature are 900 °C and 600 °C, respectively. When the reaction is carried out at 70 °C with a methanol/oil molar ratio of 12:1, a catalyst concentration of 5% and a reaction time of 1.5 h, the FMS-catalyst is active for 7 reaction cycles, with the biodiesel yield above 90%. The experimental results indicate that the FMS can be used as an economic catalyst for the biodiesel production.     

24万t/a甲醇装置水冷器的改造

简述了24万t/a甲醇装置水冷器的运行情况。针对水冷器存在内漏的问题进行分析,发现甲醇水冷器折流板及管板结构设计不合理及管板与换热管焊接工艺不合理,是造成水冷器换热管泄漏的主要原因。通过将折流板结构由单弓形竖直排列方式改为水平排列方式,厚度由12mm增加到16mm;管板复合板由扎制法改为堆焊形式,材质由0Cr18Ni10Ti改为16MnⅢ+0Cr18Ni10Ti,堆焊层为6mm;管板与换热管焊缝宽由1.33mm增加为2mm等措施,彻底解决了换热管断裂引起的内漏问题。改造后的甲醇水冷器运行稳定,经济效益良好。