It is necessary to reduce hydrogen consumption to meet increasingly strict environmental and product-quality regulations for refinery plants. In this paper, the concentration potential concepts proposed for design of ...It is necessary to reduce hydrogen consumption to meet increasingly strict environmental and product-quality regulations for refinery plants. In this paper, the concentration potential concepts proposed for design of water-using networks are extended to synthesis of hydrogen networks with multiple contaminants. In the design procedure, the precedence of processes is determined by the values of concentration potential of demands.The usage of complementary source pair(s) to reduce utility consumption is investigated. Three case studies are presented to illustrate the effectiveness of the method. It is shown that the design procedure has clear engineering meaning.展开更多
Contribution of first flush runoff events from intense rainfall to downstream aquatic ecosystems are often reported in terms of sediment and nutrient delivery, with hardly any consideration to the contribution that st...Contribution of first flush runoff events from intense rainfall to downstream aquatic ecosystems are often reported in terms of sediment and nutrient delivery, with hardly any consideration to the contribution that standing, concentrated tailwater in primary aquatic systems makes to downstream nutrient loads. Two geographically distinct studies （Jonesboro Arkansas, and Stoneville Mississippi; 4 studies, n = 30） evaluated the effectiveness of drainage ditch systems to mitigate nutrient concentrations and loads. Within each independent study all experimental ditches had elevated background nutrient concentrations as a result of standing water, prior to the start of each simulated runoff experiment. These concentrations remained elevated 15-30 minutes post the start of each simulation as the concentrated, impounded water was pushed out through each system. In both these systems, it was hypothesized that water had accumulated in the respective drainage ditches and had been concentrated though evaporation and aquatic macrophyte transpiration. It is theorized that additional controlled drainage with improved dilution and hydraulic residence management.展开更多
基金Supported by the National Natural Science Foundation of China(21176057)the National Basic Research Program of China(2012CB720305)the State Key Laboratory of Chemical Engineering(Open Research Project Skloche-K-2011-04)
文摘It is necessary to reduce hydrogen consumption to meet increasingly strict environmental and product-quality regulations for refinery plants. In this paper, the concentration potential concepts proposed for design of water-using networks are extended to synthesis of hydrogen networks with multiple contaminants. In the design procedure, the precedence of processes is determined by the values of concentration potential of demands.The usage of complementary source pair(s) to reduce utility consumption is investigated. Three case studies are presented to illustrate the effectiveness of the method. It is shown that the design procedure has clear engineering meaning.
文摘Contribution of first flush runoff events from intense rainfall to downstream aquatic ecosystems are often reported in terms of sediment and nutrient delivery, with hardly any consideration to the contribution that standing, concentrated tailwater in primary aquatic systems makes to downstream nutrient loads. Two geographically distinct studies （Jonesboro Arkansas, and Stoneville Mississippi; 4 studies, n = 30） evaluated the effectiveness of drainage ditch systems to mitigate nutrient concentrations and loads. Within each independent study all experimental ditches had elevated background nutrient concentrations as a result of standing water, prior to the start of each simulated runoff experiment. These concentrations remained elevated 15-30 minutes post the start of each simulation as the concentrated, impounded water was pushed out through each system. In both these systems, it was hypothesized that water had accumulated in the respective drainage ditches and had been concentrated though evaporation and aquatic macrophyte transpiration. It is theorized that additional controlled drainage with improved dilution and hydraulic residence management.
