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《中国石油和化工标准与质量》2014,(11)
随着天然气水合物开采及开发技术研究的不断发展,水合物的宏观流动特性研究成为保证天然气水合物顺利输送的必要条件。为此,对天然气水合物在管道中的稳定流动状态及临界堵塞条件进行了研究,以传统的固液双层流动模型为基础,结合天然气水合物在水平管道中的流动特点,提出了天然气水合物稳定流动的判定标准——临界流动速度和临界床层高度,即管道内出现固定床层的临界速度和该速度对应的床层高度;并提出了计算天然气水合物流型及流动参数的方法。在此基础上,对天然气水合物在管道中流动的沉积特性进行了研究,设计正交方案,对比了不同因素对临界沉积速度的影响因子。实验验证结果表明:该方法可以较为准确地描述天然气水合物的流动状态及其特征参数,对判断其安全流动具有一定的指导意义。 相似文献
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竖直降液膜流动在反应工程中的应用 总被引:1,自引:0,他引:1
竖直元件上的降液膜流动由于具有传热传质系数高、气液接触面积大和表面更新速度快等优点,因而在化工和聚合反应工程上有着广泛应用。本文综述了竖直降膜元件上液膜流动的实验研究、理论分析和数值模拟,分别介绍了低黏流体降液膜流动在气体吸收与化学反应等方面的应用和高黏流体降液膜流动在涂覆与聚合物脱挥等聚合物加工中的应用情况。总结表明,目前对于低黏流体在竖直元件上的降液膜流动研究已较为成熟,而高黏流体降液膜流动的大部分研究仅着重于其成膜性能上。最后分析了降液膜流动的研究趋势,指出涉及热质传递与化学反应耦合的高黏流体在竖直结构上的降液膜流动是今后的重点研究对象。 相似文献
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水合物安全流动技术作为一种新型的天然气运输管理方法具有广阔的发展前景,本文在综述国内外天然气水合物安全流动研究的基础上,分析了管道流动天然气水合物生成机理、特点和对油气管道的不利影响以及现有水合物安全流动研究存在的问题,包括实验管道长度较短、着重流动规律的研究而缺乏对流动边界的拓展等。进而对国内外天然气水合物低剂量抑制剂(low dosage hydrate inhibitor,LDHI)在保障天然气水合物安全流动、拓展天然气水合物安全流动边界以及螺旋流携带研究进行了总结评述;随后提出了利用螺旋流悬浮输送技术保障天然气水合物安全流动、拓展流动边界的新型方法。结合实验结果分析表明:螺旋流动从宏观上改变水合物浆体流动特点、有效提高水合物浆液的输送浓度并可拓展水合物安全流动边界。 相似文献
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在掌握储层流动单元概念的基础上,系统总结了目前划分储层流动单元的各种方法。综合运用多学科理论,对我国东部某复杂断块油田应用聚类分析法找到了划分流动单元的有效参数和定量界限,并在该断块整套储层中定量划分出四套流动单元,它们各自具有不同的岩性和储层物性。综合研究流动单元类型与剩余油分布的密切关系,揭示了该断块油田流动单元类型与剩余油分布的关系。 相似文献
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The effectiveness of large single applications of North Carolina reactive rock phosphate, Queensland non-reactive rock phosphate, and Calciphos, were compared to the effectiveness of superphosphate in field experiments in south-western Australia for up to 11 years after application. As measured using plant yield, superphosphate was the most effective fertilizer in the year of application, and relative to freshly-applied superphosphate, the effectiveness of the superphosphate residues declined to be about 15 to 65% as effective in the year after application, and 5 to 20% as effective 9 to 10 years after application. Relative to freshly-applied superphosphate, all the rock phosphates were 10 to 30% as effective in the year of application, and the residues remained 2 to 20% as effective in the 10 years after application. The bicarbonate soil test reagent predicted a more gradual decrease in effectiveness of superphosphate of up to 70% 10 years after application. For rock phosphate, the reagent predicted effectiveness to be always lower than for superphosphate, being initially 2 to 11% as effective in the year after application, and from 10% to equally as effective 10 years later. Therefore rock phosphates are unlikely to be economic alternatives to superphosphate in the short or long term on most lateritic soils in south-western Australia. 相似文献
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5种新型杀菌剂对4种鱼的急性毒性及安全性评价 总被引:1,自引:0,他引:1
为评价5种新型杀菌剂的环境安全性,采用半静态法测定了其对4种鱼的急性毒性。结果表明,氟醚菌酰胺对斑马鱼、稀有鮈鲫和凤尾鲫的LC_(50)(96 h)均大于100 mg/L,对青鳉的LC_(50)(96 h)为35.25 mg/L,其急性毒性均为低毒;氟吡菌胺对斑马鱼、青鳉、稀有鮈鲫和凤尾鲫的LC_(50)(96 h)分别为1.49、0.56、0.35、1.04 mg/L,其对斑马鱼和凤尾鲫急性毒性为中毒,对青鳉和稀有鮈鲫为高毒;苯噻菌胺对斑马鱼、稀有鮈鲫和凤尾鲫的LC_(50)(96 h)均大于100 mg/L,对青锵的LC_(50)(96 h)为88.23mg/L,其急性毒性均为低毒;嘧菌酯对斑马鱼、青鳉、稀有鮈鲫和凤尾鲫的LC_(50)(96 h)分别为106.80、0.44、85.96、4.61 mg/L,其对斑马鱼和稀有鮈鲫急性毒性为低毒,对青鳉急性毒性为高毒,对凤尾鲫为中毒;醚菌酯对斑马鱼、青鳝、稀有鮈鲫和凤尾鲫的LC_(50)(96 h)分别为0.77、0.66、0.51、0.81 mg/L,其对4种鱼急性毒性均为高毒。明确这些药剂的环境安全性对指导其科学使用,保护环境生物均有较大意义。 相似文献
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MichelRigaud ZHOUNingsheng 《中国耐火材料》2002,11(2):3-8
An analysis of the present and of the future of the refractories industry is being presented,considering some improtant techincal,economical,human and environmental issues,on a worldwide basis,Refractories still needed as confinement materials to prevent heat and mass transfer losses in many diverse manufacturing industries,and will remain so ,but the main challenges,this industry do need to neet,are to adjust to and overcapacity production ,to cope with new needs of the customers,in particular the “outsourcing“,which is a new custome/supplier rela-tionship being adopted by many of them,and more compet-itive arena.Among the direct consequences,are the need to keep the education world in refractory engineering training aliver and to cope with macro and micro projects to change the image of the Refractories,from a commodity material to a sophisticated “high-tech“ compostie material.Some suggestions are provided in the text. 相似文献
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针对尿素生产的特点,分析了对尿素设备腐蚀的影响因素:介质温度、氨碳摩尔比、水碳摩尔比、氨基甲酸铵溶液浓度、氧含量、硫含量、氯离子含量和介质流速等。提出了正常生产和停车封塔2种情况下的防腐措施。正常生产期间要严格控制如下指标:操作温度、系统的加氧量、硫含量、氯离子含量、氨碳比和水碳比;停车期间要严格控制系统的氨碳比和水碳比,同时根据不同状况来确定停车封塔时间。 相似文献
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The aim of this work is to analyse the possibility of using co-gasification technology to process coal mixed with wastes to take profit of its energy content and at the same time to minimize the environmental impact associated with the use of wastes and to diminish the costs of flue gas treatment. The addition to coal of different types of materials, like: pine based waste, petcoke and polyethylene (PE), was not found to give rise to any operational problems, regarding both the feeding system and gasification process and led to higher energy conversions, however, the gas presented higher tars and hydrocarbons content. Several catalysts were tested, such as, dolomite, olivine, nickel and magnesium oxides, zinc oxides and cobalt and molybdenum oxides. Catalyst action was analysed in tars release and also in ammonia compounds reduction. The presence of catalysts allowed increasing hydrogen release, whilst there was a decrease in hydrocarbons and tars contents. A nickel-magnesium oxide was the catalyst that led to the highest reduction in hydrocarbons and tars. This catalyst also led to the lowest NH3 content in the fuel gas produced, due to the catalyst efficiency in NH3 destruction. 相似文献
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介绍了斯托克斯(Stokes)定律与电脱盐(EDD)原理,叙述了2者结合在炼油厂常压-催化车间的应用,解决了油与无机盐及水的分离问题.(1)增加液-液旋流分离器,使进污水汽提塔的污水含油量降低了89%,解决了焚烧炉下火雨及炉膛超温的问题;(2)先后2次改造电脱盐流程及电脱盐罐,并应用鼠笼式平流电脱盐技术,使脱后含盐质量分数由8.74mg/L降为1.45 mg/L,含水的质量分数由0.43%降为0.11%,脱盐率由81.4%增加到96.4%.可保护催化剂,提高催化液收收率,降低成本,并稳定安全生产. 相似文献
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Ian Jeffery Bonner David N. Thompson Mitchell Plummer Matthew Dee Jaya Shankar Tumuluru David Pace 《Drying Technology》2016,34(11):1319-1329
Pretreatment and densification of biomass can increase the viability of bioenergy production by providing a feedstock that is readily hydrolyzed and able to be transported over greater distances. Ammonia fiber expansion (AFEX?) is one such method targeted for use at distributed depots to create a value-added and densified feedstock for bioenergy use. However, the pretreatment process results in a high-moisture material that must be dried, further size reduced, and pelletized, all of which are energy-intensive processes. This work quantifies the energy consumption required to dry, grind, and densify AFEX-pretreated corn stover compared to non-pretreated stover and explores the potential of reduced drying as a means to conserve energy. The purpose of this work is to understand whether material property changes resulting from AFEX pretreatment influence the material performance in downstream formatting operations. Material properties, heat balance equations, and a rotary drum dryer model were used to model a commercial-scale rotary drum dryer for AFEX-pretreated corn stover, showing the potential to reduce dryer energy consumption by up to 36% compared to non-pretreated corn stover. Laboratory-measured grinding and pelleting energies were both very sensitive to material moisture content. Overall, the total energy required for drying, grinding, and pelleting amounts to a savings of up to 23 kWh/dry Mg for the AFEX-pretreated material when dried to a low moisture content, equating to up to 0.61 $/Mg savings for gas and electricity. Grinding and pelleting of high-moisture AFEX-pretreated stover was shown to be more costlier than the savings collected through reduced drying. Although the energy and cost savings shown here are modest, the results help to highlight operational challenges and opportunities for continued improvement. 相似文献
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以磷肥、黄磷、热法磷酸、三聚磷酸钠、饲料磷酸氢钙等产品为例,阐述了基础磷化工产业现状,针对基础磷化工产品同质化、技术等同化、市场过剩的局面,分析了产生问题的原因。指出基础磷化工必须淘汰落后产能,必须依靠技术进步降低生产成本,实现产品结构的升级与调整;而技术进步的重点在于实现原子经济效益、能源利用和劳动生产效率三者的最大化以及消耗的最小化,要不断开发满足社会需求的新产品。此外,还对相关的政策法规和规章制度提出建议。 相似文献
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离子型活性剂能在水溶液中电离出大量带电的离子,牢固地吸附在颜料粒子的表面,并具有相同电荷,其它带相反电荷的离子则自由扩散到液体介质的周围,形成一个带电离子的扩散层。这些带相同电荷的粒子一经接触就相互排斥,从而保持分散体系的稳定。因为表面活性剂能够定向地吸附在颜料粒子的表面,形成一种单分子吸附层,这种定向缓冲层能防止粒子间的相聚,从而保持分散体系的稳定。本文采用溶液吸附法加入离子型和非离子及高分子量的表面活性剂,在颜料的表面上形成吸附层,经过反复实验后,选择出了一种分散性能较为理想的的表面活性剂,改善了涂料贮存方面的缺点,并使涂膜便于在底材上展布,降低了涂料的生产成本和提高了生产效率。 相似文献