共查询到20条相似文献,搜索用时 125 毫秒
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通过对成品油管道油品切换操作、清管污油处置等工作上的特殊性进行分析,对混油拖尾、油源质量潜力及回掺设备选型对成品油管道混油回掺工作产生的影响进行总结,对质量流量计标定设施的设计缺陷进行研究。华北成品油管网有针对性地在油品注入流程、混油处置设施及质量流量计标定设施等站场工艺上采取改进措施,达到防止注入油品窜油、混油全部回掺处理及质量流量计在线标定正常投用的目标。同时,提出增加成品油管道混油处理能力、设置清管污油专项处理设施的设计建议,指出在成品油管道站场工艺设计阶段应考虑成品油管道的特殊性,以提高管道的适用性。 相似文献
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根据DN400-DN1000铸管外表面质量常出现轨道印等问题,找出影响铸铁管外表面喷涂质量的直接原因是预热炉和加热炉温度.对加热炉上部管式换热器、下部烧嘴、预热炉进风口、门帘、隔墙及送风管道、引风机进出风口进行改造.改进后,预热炉预热温度满足工艺要求,铸管外表面轨道印、起皮缺陷基本消除. 相似文献
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在酸性条件下,管道腐蚀相当严重,产生的危害也很大.因此,进行金属防腐分析具有重要意义.文中对国内外天然气管道的使用情况进行了介绍,并对这些管道的材质以及特点进行了说明.针对腐蚀发生的不同原因,介绍了采用涂防腐绝缘层、阴极保护和连接线等有效延缓管道腐蚀的防护措施,并分析了各自的优缺点.实际上,既经济可行又有效的防腐方法是... 相似文献
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"超限超载"的产生与发展,蕴藏着深层的内在运作机理,包含着复杂的经济社会原因.其中道路货物运输价格体系的长期扭曲失衡与成本结构的有欠合理是一个不容忽视的根本原因.为此,公路所开展了货运市场运价与成本"治超"专项研究,先后历时一个多月,行程数千公里,深入7省市运输一线,对21家典型企业和个体业户的23辆货车、24条线路进行了跟踪调查,获取了大量的第一手资料与原始数据,并对此进行了解析. 相似文献
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Ngila Mwase† 《运输评论》2013,33(3):191-206
Zambia has attempted to reduce her excessive transport dependency on her traditional transport routes via South Africa and the former Portugese colonies. The costly construction of the Tanzania‐Zambia Railway (TAZARA) was part of this diversification strategy. This article examines the nature, extent and direction of Zambian traffic, including its historical evolution. It explores further the place of TAZARA among the various routes to Mozambican, Angolan and South African ports, and the ensuing actual and potential competition. Future traffic patterns will be influenced not only by the direct and service‐oriented costs of the different lines, but also by the region's volatile and uncertain political climate. 相似文献
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针对海中箱梁现浇施工中的工程量大、工期紧迫、悬臂法施工不能满足工期要求和施工难度大等问题,文章结合青岛海湾大桥箱梁现浇施工实践,介绍以钢管桩支撑作为承载基础,采用贝雷梁与碗扣式支架相结合的支架,成功地解决现浇箱梁施工难题的方法。 相似文献
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Robert E. Paaswell 《Transportation》1973,2(4):351-371
An examination of current population statistics shows that in the U.S. more than half of the population is without immediate access to a car, and in the U.K. more than three-fifths of the population is without access to a car. This phenomenon has been accentuated by national investment in both countries in major highway programs. The term carless refers to more than just households that own no cars. It extends, in households with cars to those without licenses (old and young), the handicapped, and even the licensed drivers who have no access to the family car when it is in use elsewhere (e.g. at work). The most severely effected are those in urban areas and especially the urban poor. Transportation expenses are limited for the poor when other family expenditures (food, shelter) take a high priority. Once the work trip has been satisfied, money for other trips, for the poor, is not always available. One solution to cost-free travel is pedestrianism (walking), but this too is difficult in urban areas where the pedestrian has been overlooked in favor of the car. Solutions to problems of the carless include dial-a-ride, better public transit, and better design of urban form. 相似文献