Water-oxygen pinch analysis is an effective method to decrease the wastewater quantity and improve the wastewater quality. But when multiple-contaminants are present, the method is difficult to be carried out. In this...Water-oxygen pinch analysis is an effective method to decrease the wastewater quantity and improve the wastewater quality. But when multiple-contaminants are present, the method is difficult to be carried out. In this paper, the method that combines water-oxygen pinch analysis with mathematical programming is proposed. It obtains the general optimal solution and leads to the reuse stream that cannot be found only by pinch analysis. The new method is illustrated by an example, and the annual cost is reduced by 8.43% compared with the solution of literature.展开更多
This paper introduces a non-iterative algorithmic procedure to design water utilization networks with multiple contaminants in process plants. According to the water pinch analysis rules, the processes in water utiliz...This paper introduces a non-iterative algorithmic procedure to design water utilization networks with multiple contaminants in process plants. According to the water pinch analysis rules, the processes in water utilization systems were first divided into three groups, then water-supply priority algorithm was proposed. The results of case studies showed that the water networks designed by this method gave water consumption lower than that estimated by other approaches. In addition, the procedure was subject to no limitation on the problem scale.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
Supercritical Water Gasification is an efficient technology in converting wet biomass into H2 and CH4 in comparison to other conventional thermochemical processes. Coke deposition, however, remains as a major challeng...Supercritical Water Gasification is an efficient technology in converting wet biomass into H2 and CH4 in comparison to other conventional thermochemical processes. Coke deposition, however, remains as a major challenge in this technology. Coke formation is the result of polymerization reactions that take place at sub-critical conditions. Directly injecting the relatively unheated wet biomass feed into supercritical water increases the heating rate and reduces the residence time of the feed in the sub-critical condition. This leads to a minimized coke formation in the process. However, a non-isothermal mixing takes place during this direct injection that is less energy-efficient. In addition, the biomass feedstream experiences less pre-heating that means less heat recovery from the product gas. These two aspects might reduce the overall process performance. Parametric studies of key operating parameters, such as operating temperature, dry matter content, bypass water ratio and heat exchanger effectiveness, are carried out to investigate the influence of direct injection to the thermal efficiency of the system. Subsequently, optimization using pinch analysis is conducted to the system with direct injection. Finally, an operating window for optimum performance of the optimized direct injection gasification system is proposed.展开更多
文摘Water-oxygen pinch analysis is an effective method to decrease the wastewater quantity and improve the wastewater quality. But when multiple-contaminants are present, the method is difficult to be carried out. In this paper, the method that combines water-oxygen pinch analysis with mathematical programming is proposed. It obtains the general optimal solution and leads to the reuse stream that cannot be found only by pinch analysis. The new method is illustrated by an example, and the annual cost is reduced by 8.43% compared with the solution of literature.
文摘This paper introduces a non-iterative algorithmic procedure to design water utilization networks with multiple contaminants in process plants. According to the water pinch analysis rules, the processes in water utilization systems were first divided into three groups, then water-supply priority algorithm was proposed. The results of case studies showed that the water networks designed by this method gave water consumption lower than that estimated by other approaches. In addition, the procedure was subject to no limitation on the problem scale.
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。
文摘Supercritical Water Gasification is an efficient technology in converting wet biomass into H2 and CH4 in comparison to other conventional thermochemical processes. Coke deposition, however, remains as a major challenge in this technology. Coke formation is the result of polymerization reactions that take place at sub-critical conditions. Directly injecting the relatively unheated wet biomass feed into supercritical water increases the heating rate and reduces the residence time of the feed in the sub-critical condition. This leads to a minimized coke formation in the process. However, a non-isothermal mixing takes place during this direct injection that is less energy-efficient. In addition, the biomass feedstream experiences less pre-heating that means less heat recovery from the product gas. These two aspects might reduce the overall process performance. Parametric studies of key operating parameters, such as operating temperature, dry matter content, bypass water ratio and heat exchanger effectiveness, are carried out to investigate the influence of direct injection to the thermal efficiency of the system. Subsequently, optimization using pinch analysis is conducted to the system with direct injection. Finally, an operating window for optimum performance of the optimized direct injection gasification system is proposed.
