Work exchange is a promising innovative technology in recovering residual pressure energy. However, at the systematic level, the comprehensive utilization of different energy resources in an energy system has become a...Work exchange is a promising innovative technology in recovering residual pressure energy. However, at the systematic level, the comprehensive utilization of different energy resources in an energy system has become an issue of concern. In this work, a systematic approach is proposed, one that successively integrates heat, work and adjusts operation parameters. A detailed procedure for building a heat-work coupling transfer network is provided. The synthesis mainly consists of constructing a work exchange sub-network with pinch analysis based on positive displacement type work exchangers. Simultaneously, another kind of sub-network based on turbine-type work exchangers is built as a schematic comparison. The influence of applying a positive displacement work exchanger on the system is investigated. Finally, as a case study, a renovation design of a typical rectisol process in the coal-water slurry gasification section of an ammonia plant is presented. The results show that the added work exchanger has little impact on the existing heat exchange sub-network. Moreover,extra pressure energy is recovered by coupling the transfer network. It is concluded that the heat-work systematic design is a promising and powerful method to use energy more efficiently.展开更多
Energy efficiency has become an important feature in the design of process plants with the rising cost of energy and the more stringent environmental regulations being implemented worldwide. In South Africa, as elsewh...Energy efficiency has become an important feature in the design of process plants with the rising cost of energy and the more stringent environmental regulations being implemented worldwide. In South Africa, as elsewhere, most process plants built during the era of cheap energy place little emphasis on the need for energy recovery due to the abundance of cheap utilities sources such as coal. In most of these plants, there exist significant potential for substantial process heat recovery by conceptual design of the heat recovery system. By maximizing heat recovery from the processes, there will be a reduction in the process utilities requirement and the associated environmental effects. Pinch analysis has been demonstrated to be a simple but very effective tool for heat integration and optimization of chemical plants. This study uses the pinch principle to retrofit the heat exchanger networks (HEN) of the crude distillation unit of an integrated petroleum refinery to evolve a HEN that features optimum energy recovery. The network was further relaxed by trading off energy cost with capital cost to obtain an optimal HEN topology not too different from the existing network. The simulation works were implemented in AspenPlus v8.0 environment. Analysis revealed that 34 per cent saving on energy usage per annum is realizable. This significant saving in energy also results in diminished gaseous pollutants associated with energy usage.展开更多
To realize the industrialization of the novel single-column air separation process proposed in previous work,steady-state simulation for four different configurations of the single-column process with ternary(nitrogen...To realize the industrialization of the novel single-column air separation process proposed in previous work,steady-state simulation for four different configurations of the single-column process with ternary(nitrogen,oxygen and argon)is developed.Then,exergy analysis of the single-column processes is also carried out and compared with the conventional double-column air separation process at the same capacity.Furthermore,based on the steady-state simulation of single-column processes,the different heat exchanger networks(HENs)for the main heat exchanger and subcooler in each process are designed.To obtain better performance for this novel process,optimization of process configuration and operation is investigated.The optimal condition and configuration for this process is consisted as:feedstock is divided into two streams and the reflux nitrogen is compressed at the approximate temperature of 301 K.In addition,HEN is optimized to minimize the utilities.HENs without utilities are obtained for the four different configurations of single-column process.Furthermore,capital costs of the HEN for different cases are estimated and compared.展开更多
利用Aspen Plus对某炼油厂4.20 Mt/a催化裂化(FCC)装置进行建模预测。基于所建模型提取装置冷热物流数据,利用夹点技术对整个装置进行换热网络分析,发现原FCC装置吸收稳定系统存在能耗高、热公用工程消耗大,原料油混合温差大,轻柴油、...利用Aspen Plus对某炼油厂4.20 Mt/a催化裂化(FCC)装置进行建模预测。基于所建模型提取装置冷热物流数据,利用夹点技术对整个装置进行换热网络分析,发现原FCC装置吸收稳定系统存在能耗高、热公用工程消耗大,原料油混合温差大,轻柴油、重柴油及产品油浆高质低用,除盐水终温较低,除氧器蒸汽消耗量大等问题。通过优化稳定塔回流比、补充吸收剂流量等方法降低吸收稳定系统负荷,优化分馏塔中段取热比例多产高品位蒸汽,并利用夹点技术优化装置换热网络。结果表明:优化后,可节省蒸汽量27.3 t h,相当于节能16603 tOE a(1 tOE=41.8 GJ)或23757 tCE a(1 tCE=29.27 GJ),减少二氧化碳排放量76457 t a,节能效果优异;同时,改造还减少FCC装置外送热媒水量300 t h,装置内利用热媒水10.27 MW的余热,减少了热量损失。展开更多
基金supported by the National Natural Science Foundation of China (No. 20936004 and No. 21376187)
文摘Work exchange is a promising innovative technology in recovering residual pressure energy. However, at the systematic level, the comprehensive utilization of different energy resources in an energy system has become an issue of concern. In this work, a systematic approach is proposed, one that successively integrates heat, work and adjusts operation parameters. A detailed procedure for building a heat-work coupling transfer network is provided. The synthesis mainly consists of constructing a work exchange sub-network with pinch analysis based on positive displacement type work exchangers. Simultaneously, another kind of sub-network based on turbine-type work exchangers is built as a schematic comparison. The influence of applying a positive displacement work exchanger on the system is investigated. Finally, as a case study, a renovation design of a typical rectisol process in the coal-water slurry gasification section of an ammonia plant is presented. The results show that the added work exchanger has little impact on the existing heat exchange sub-network. Moreover,extra pressure energy is recovered by coupling the transfer network. It is concluded that the heat-work systematic design is a promising and powerful method to use energy more efficiently.
文摘Energy efficiency has become an important feature in the design of process plants with the rising cost of energy and the more stringent environmental regulations being implemented worldwide. In South Africa, as elsewhere, most process plants built during the era of cheap energy place little emphasis on the need for energy recovery due to the abundance of cheap utilities sources such as coal. In most of these plants, there exist significant potential for substantial process heat recovery by conceptual design of the heat recovery system. By maximizing heat recovery from the processes, there will be a reduction in the process utilities requirement and the associated environmental effects. Pinch analysis has been demonstrated to be a simple but very effective tool for heat integration and optimization of chemical plants. This study uses the pinch principle to retrofit the heat exchanger networks (HEN) of the crude distillation unit of an integrated petroleum refinery to evolve a HEN that features optimum energy recovery. The network was further relaxed by trading off energy cost with capital cost to obtain an optimal HEN topology not too different from the existing network. The simulation works were implemented in AspenPlus v8.0 environment. Analysis revealed that 34 per cent saving on energy usage per annum is realizable. This significant saving in energy also results in diminished gaseous pollutants associated with energy usage.
基金Supported by the National Natural Science Foundation of China(21576228)
文摘To realize the industrialization of the novel single-column air separation process proposed in previous work,steady-state simulation for four different configurations of the single-column process with ternary(nitrogen,oxygen and argon)is developed.Then,exergy analysis of the single-column processes is also carried out and compared with the conventional double-column air separation process at the same capacity.Furthermore,based on the steady-state simulation of single-column processes,the different heat exchanger networks(HENs)for the main heat exchanger and subcooler in each process are designed.To obtain better performance for this novel process,optimization of process configuration and operation is investigated.The optimal condition and configuration for this process is consisted as:feedstock is divided into two streams and the reflux nitrogen is compressed at the approximate temperature of 301 K.In addition,HEN is optimized to minimize the utilities.HENs without utilities are obtained for the four different configurations of single-column process.Furthermore,capital costs of the HEN for different cases are estimated and compared.
文摘利用Aspen Plus对某炼油厂4.20 Mt/a催化裂化(FCC)装置进行建模预测。基于所建模型提取装置冷热物流数据,利用夹点技术对整个装置进行换热网络分析,发现原FCC装置吸收稳定系统存在能耗高、热公用工程消耗大,原料油混合温差大,轻柴油、重柴油及产品油浆高质低用,除盐水终温较低,除氧器蒸汽消耗量大等问题。通过优化稳定塔回流比、补充吸收剂流量等方法降低吸收稳定系统负荷,优化分馏塔中段取热比例多产高品位蒸汽,并利用夹点技术优化装置换热网络。结果表明:优化后,可节省蒸汽量27.3 t h,相当于节能16603 tOE a(1 tOE=41.8 GJ)或23757 tCE a(1 tCE=29.27 GJ),减少二氧化碳排放量76457 t a,节能效果优异;同时,改造还减少FCC装置外送热媒水量300 t h,装置内利用热媒水10.27 MW的余热,减少了热量损失。
