生物甲烷系统的能耗-绿色度两目标优化

针对生物质发酵制备生物甲烷这一复杂系统,本文以能耗和环境影响作为2个优化的目标函数,以温度、压力和回收率等为优化变量,并同时以质量守恒、能量守恒、技术选择和环境影响为约束条件,建立了两目标的混合整数非线性规划(MINLP)模型。其中,能耗目标以生产单位甲烷所需要消耗的能量为评价标准,环境影响目标则以生产单位甲烷的系统的绿色度为评价标准。同时,本文采用绿色度方法对低劣生物质和沼液沼渣的环境影响进行定量的分析和评价。针对这一复杂非线性优化问题,采用非支配排序遗传算法(NSGA-II)进行求解并得到系列Pareto优化解集。优化结果定量地揭示了各目标之间的权衡关系。同时,优化结果可为决策者提供有价值...</p

醚基复合氯铝酸离子液体催化异丁烷烷基化

制备了4种醚基离子液体(1-甲氧基乙基-3-甲基咪唑氯盐MOEMIMCl、1-甲氧基乙基-3-甲基咪唑溴盐MOEMIMBr、 N,N,N-三甲基-N-甲氧基乙基溴化铵N_(111,1O_2)Br和N,N,N-三乙基-N-甲氧基乙基溴化铵N_(222,1O_2)Br),作为三乙胺盐酸盐氯铝酸离子液体的助剂催化异丁烷烷基化反应,考察了4种醚基离子液体及其添加量对氯铝酸离子液体催化烷基化的影响.结果表明,在反应温度25℃、进料速率500 mL/h、酸烃体积比20:60、添加6%(w)MOEMIMCl的条件下,C8选择性由47.7%提高至63.6%,辛烷值(RON)由83.5提高至93.2.优化后的醚基复合氯铝酸离子液体催化剂至少循环20次活性不降低,显示了较好的催化性能.醚基离子液体助剂对烷基化性能的提高可归功于提高异丁烷溶解度、抑制酸度降低和提高界面性能

醚基复合氯铝酸离子液体催化异丁烷烷基化

制备了4种醚基离子液体(1-甲氧基乙基-3-甲基咪唑氯盐[MOEMIM]Cl、1-甲氧基乙基-3-甲基咪唑溴盐[MOEMIM]Br、N,N,N-三甲基-N-甲氧基乙基溴化铵[N_(111,1O_2)]Br和N,N,N-三乙基-N-甲氧基乙基溴化铵[N_(222,1O_2)]Br),作为三乙胺盐酸盐氯铝酸离子液体的助剂催化异丁烷烷基化反应,考察了4种醚基离子液体及其添加量对氯铝酸离子液体催化烷基化的影响.结果表明,在反应温度25℃、进料速率500 mL/h、酸烃体积比20:60、添加6%(w)[MOEMIM]Cl的条件下,C8选择性由47.7%提高至63.6%,辛烷值(RON)由83.5提高至93.2.优化后的醚基复合氯铝酸离子液体催化剂至少循环20次活性不降低,显示了较好的催化性能.醚基离子液体助剂对烷基化性能的提高可归功于提高异丁烷溶解度、抑制酸度降低和提高界面性能.</p

原油常减压蒸馏装置的流程模拟及参数优化

根据某原油常减压蒸馏装置的工艺流程,采用Aspen Plus软件对装置的初馏塔、常压塔和减压塔进行流程模拟计算,获得了各产品的温度、流量等关键参数及减压塔侧线产品的馏程曲线,并与实际数据对比,二者吻合良好.分析了塔板温度和气液相流量沿塔板的分布,运用灵敏度分析工具对相关参数进行优化,优化后常压塔柴油收率可增加0.22t/h,常压塔热负荷降低6.3%,减压塔轻油收率上升0.18%,减压塔热负荷降低11.2%

原油常减压蒸馏装置的流程模拟及参数优化

根据某原油常减压蒸馏装置的工艺流程,采用Aspen Plus软件对装置的初馏塔、常压塔和减压塔进行流程模拟计算,获得了各产品的温度、流量等关键参数及减压塔侧线产品的馏程曲线,并与实际数据对比,二者吻合良好.分析了塔板温度和气液相流量沿塔板的分布,运用灵敏度分析工具对相关参数进行优化,优化后常压塔柴油收率可增加0.22t/h,常压塔热负荷降低6.3%,减压塔轻油收率上升0.18%,减压塔热负荷降低11.2%

原油常减压蒸馏装置的流程模拟及参数优化

根据某原油常减压蒸馏装置的工艺流程,采用Aspen Plus软件对装置的初馏塔、常压塔和减压塔进行流程模拟计算,获得了各产品的温度、流量等关键参数及减压塔侧线产品的馏程曲线,并与实际数据对比,二者吻合良好.分析了塔板温度和气液相流量沿塔板的分布,运用灵敏度分析工具对相关参数进行优化,优化后常压塔柴油收率可增加0.22t/h,常压塔热负荷降低6.3%,减压塔轻油收率上升0.18%,减压塔热负荷降低11.2%

Development of a Stereoselective Approach for the Synthesis of Allo Bile Acids

Bile acids are natural products that are located within a variety of organisms through metabolism of cholesterol. The less common allo bile acids contain a trans AB ring fusion and are designated as the C5α diastereomers. Although Iqbal, and Tochtrop have described synthetic approaches to the 5α stereocenter, there still remain issues of stereoselectivity and chemoselectivity when forging the AB trans ring. We have established a general approach to the synthesis of allo bile acids by applying a recently developed manganese catalyzed hydrogen atom transfer reduction. This key tactic enabled us to successfully synthesize allolithocholic acid over seven steps in 26% yield and 97% diastereomer purity, starting with the commercially available lithocholic acid. Notably, this is the first reported synthesis of allolithocholic acid. Derivatives of lithocholic acid were also synthesized to explore the hydrogen atom transfer reaction in order to develop an understanding of the reaction outcome in terms of stereoselectivity. Finally, this synthetic tactic was also applied to the synthesis of other allo bile acid derivatives such as deoxycholic, chenodeoxycholic, and hyodeoxycholic acids. The later chapter in this thesis describes a synthetic endeavor to develop a general approach toward the eudesmane carbon skeleton through a double addition strategy. This strategy was effective in forming the C10 quaternary center and the C6–C7 bond in the eudesmane skeleton albeit with modest stereoselectivity as a 1:1 mixture of uncharacterized diastereomers