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41.
Inferior crude oil and fuel oil upgrading lead to escalating increase of hydrogen consumption in refineries. It is imperative to reduce the hydrogen consumption for energy-saving operations of refineries. An integration strategy of hydrogen network and an operational optimization model of hydrotreating (HDT) units are proposed based on the characteristics of reaction kinetics of HDT units. By solving the proposed model, the operating conditions of HDT units are optimized, and the parameters of hydrogen sinks are determined by coupling hydrodesulfurization (HDS), hydrodenitrification (HDN) and aromatic hydrogenation (HDA) kinetics. An example case of a refinery with annual processing capacity of eight million tons is adopted to demonstrate the feasibility of the proposed optimization strategies and the model. Results show that HDS, HDN and HDA reactions are the major source of hydrogen consumption in the refinery. The total hydrogen consumption can be reduced by 18.9% by applying conventional hydrogen network optimization model. When the hydrogen network is optimized after the operational optimization of HDT units is performed, the hydrogen consumption is reduced by 28.2%. When the benefit of the fuel gas recovery is further considered, the total annual cost of hydrogen network can be reduced by 3.21×107 CNY·a-1, decreased by 11.9%. Therefore, the operational optimization of the HDT units in refineries should be imposed to determine the parameters of hydrogen sinks base on the characteristics of reaction kinetics of the hydrogenation processes before the optimization of the hydrogen network is performed through the source-sink matching methods. 相似文献
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针对唐安煤矿3409工作面巷道支护特点及效果,对其巷道支护设计进行优化研究,并通过现场应用,得到了较好的经验及经济效果,为类似情况的巷道支护设计提供参考。 相似文献
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以冷分解-正浮选工艺对大浪滩某矿区的盐田光卤石进行了提钾研究,考察了分解水量、浮选时间、捕获剂用量、母液回用和精矿洗涤等对钾盐回收率及精矿品质的影响。结果表明,分解水质量以光卤石中氯化镁完全溶解理论所需的110%为宜,捕获剂用量可选用(70+20)g/t,中矿和母液的再利用可使氯化钾回收率达到95.42%。经过精矿洗涤处理,所得产品中KCl的质量分数达到了93.56%,符合GB 6549—2011农业用氯化钾优等品指标要求。优化后的正浮选工艺对大浪滩钾矿具有了更好的针对性。 相似文献
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Poly(ε‐caprolactone)‐graft‐poly(N‐isopropylacrylamide) amphiphilic copolymers prepared by a combination of ring‐opening polymerization and atom transfer radical polymerization: Synthesis,self‐assembly,and thermoresponsive property 下载免费PDF全文
Thermoresponsive graft copolymers of ε‐caprolactone and N‐isopropylacrylamide were synthesized by a combination of ring‐opening polymerization and the sequential atom transfer radical polymerization (ATRP). The copolymer composition, chemical structure, and the self‐assembled structure were characterized. The graft length and density of the copolymers were well controlled by varying the feed ratio of monomer to initiator and the fraction of chlorides along PCL backbone, which is acting as the macroinitiator for ATRP. In aqueous solution, PCL‐g‐PNIPAAm can assemble into the spherical micelles which comprise of the biodegradable hydrophobic PCL core and thermoresponsive hydrophilic PNIPAAm corona. The critical micelle concentrations of PCL‐g‐PNIPAAm were determined under the range of 6.4–23.4 mg/L, which increases with the PNIPAAm content increasing. The mean hydrodynamic diameters of PCL‐g‐PNIPAAm micelles depend strongly on the graft length and density of the PNIPAAm segment, allowing to tune the particle size within a wide range. Additionally, the PCL‐g‐PNIPAAm micelles exhibit thermosensitive properties and aggregate when the temperature is above the lower critical solution temperature. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41115. 相似文献
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Web集群服务器可用性的提高 总被引:3,自引:0,他引:3
以Web集群服务器的后端节点作为研究对象,通过减少后端节点的MTTR(Mean Timeto Repair),来提高它们的可用性,从而提高整个集群服务器的可用性。首先,通过分析现有的故障恢复方案的不足,提出了新的改进方案,在新的方案中,采用了动态地检测和发送状态信息的策略。并引入了故障猜测状态,弥补了现有方案的不足。最后设计了一个试验环境,与现有的方案测试相比,使用改进的方案,MTTR(平均敞障修复时间)减少了63%,很好地提高了后端节点的可用性。 相似文献