In this paper, a hierarchical optimization procedure for reaction path synthesis is presented in which the overall reaction is not necessarily desirable with respect to the thermodynamics or mechanism of reaction. According to the specified raw materials, desired product, and probable yproducts, the overall reactions are determined through the generation method of simple stoichiometric reactions and evaluated by economic potential and other criteria such as thermodynamic feasibility and kinetic desirability. For an overall reaction that is unachievable thermodynamically or kinetically while potentially desirable with respect to profit, a novel procedure for overall reaction decomposition by adding intermediate chemicals is proposed to realize it by several thermodynamically feasible division reactions. When this method is used, the optimal solution of reaction path synthesis can be either an overall reaction or several division reactions. A case study is described to illustrate the proposed procedure.

A systematic methodology is presented for refinery modeling and optimization on the basis of much more detailed molecular information than is used in conventional lumped methods. The novelty of this work is that it incorporates models based on microscopic understanding into optimization to achieve macroscopic improvements. A molecular matrix based on a homologous series of hydrocarbon compounds is used to characterize refining streams. A transformation method is developed for obtaining molecular compositions from stream bulk properties. Molecular models are then built for several processes. Molecular modeling and optimization are finally integrated into an overall refinery optimization framework. Results show that molecular information can provide much better understanding and new insights into refining operation. Consequently optimization based on molecular modeling can greatly improve total profit while making quality products that satisfy environmental regulations.

With more and more severe problems of environmental pollution, the chemical industry entails the consideration of minimum environmental impact when synthesizing reaction path. In this paper, a systematic method for reaction path synthesis is described in which undesirable chemicals are cycled to realize zero avoidable pollution. A novel concept of simple stoichiometric reactions (SSRs) is introduced to determine simple stoichiometries between raw materials, probable intermediate chemicals and co-products and to form a reaction path network. Promising reactions are identified by an optimization program from this network. Case studies are discussed to illustrate the proposed method.

以某天然气化工工业园为例，对其生产过程中的主要元素C进行代谢分析，C元素利用效率为65．1％，元素损失主要发生在合成氨造气和甲醇造气工段。针对元素利用率较低的工艺环节，分析了资源浪费原因和节约潜力。以分析结果为依据，结合企业生态工业发展规划提出改进方案，包括：在过程间建立物质耦合关系，通过利用副产物或废弃物减少原料的使用；改进造气工艺，提高C元素的有效利用率。对改进方案的C元素流分析表明，C元素利用率提高到88．1％，同时C02排放被有效削减。

为实现磷资源产业可持续发展，以中国磷资源产业为对象，运用投入产出分析（input output a11alvsis IOA）方法对其整个生命周期的元素代谢和物质循环进行定量描述和分析。总结磷元素高效循环利用的技术手段和措施，提出生产智能控缓释化肥、减少含磷农药使用量、减少含磷洗涤剂使用量、回收人畜粪便生产有机肥料和回收污水中的磷等措施构成6个不同方案改善该系统的物质利用水平，并对元素循环效率等指标进行分析比较。研究结果表明，合理选取、综合采用先进的循环经济技术手段，可以提高中国磷资源产业物质利用水平和元素循环效率。