液化石油气储罐设计毕业论文

天然气液化循环迄今为止,在天然气液化技术领域中成熟的液化工艺有[5 ] : (1) 阶式制冷循环; (2) 混合制冷剂制冷循环,包括闭式、开式、丙烷预冷、CII ; (3) 膨胀机制冷循环,包括天然气膨胀、氮气膨胀、氮- 甲烷膨胀等。311 阶式制冷循环阶式制冷循环又称级联式制冷循环,是用丙烷(或丙烯) 、乙烷(或乙烯) 、甲烷等纯烃制冷剂的3个制冷循环阶组成,通过制冷剂液体的蒸发,逐级提供天然气液化所需的冷量,制冷温度梯度分别为- 30 ℃、- 90 ℃及- 150 ℃左右。净化后的原料天然气在3 个制冷循环的冷却器中逐级冷却、冷凝、液化并过冷,经节流降压后获得低温常压液态天然气产品,送到储罐储存。典型的阶梯式制冷循环流程图如下图所示:图3 典型的阶梯式制冷循环阶式液化循环能耗最小,在目前天然气液化循环中效率最高,所需换热面积小(相对于混合制冷剂循环) ,且制冷循环与天然气液化系统各自独立,相互影响少、操作稳定、适应性强、技术成熟。其缺点是流程复杂、机组多,至少要有3 台压缩机,要有生产和储存各种制冷剂的设备,各制冷循环系统不允许相互渗漏,管线及控制系统复杂,管理维修不方便,对制冷剂的纯度要求严格。阶式循环最适用于大型装置。通过优化机器的选择,阶式循环可以与在基本负荷混合制冷剂厂中占主导地位的带预冷的混合制冷剂循环相竞争。Phillips 公司对传统的阶式循环进行了优化。Phillips 优化的阶式循环具有稳定的可靠性,因为在设计中考虑下列四个因素:(1) 单一组分的制冷济;(2) 用铜焊接的铝换热器;(3) “two - trains - in - one”流程;(4) 适当的服务设施该工艺显著的一点是采用“two - trains - in -one”流程,流程中采用了两组并联的压缩机组,每一个压缩机组有独立的驱动设备。这种结构使得流程的操作具有很大的灵活性,可以方便的进行压缩机组或驱动装置的维修,当原料气的进气量波动很大时仍能保持很高的效率,还可以减少了备用的驱动设备[6 ] 。312 混合制冷剂制冷循环混合制冷剂(又称多组分制冷剂) 制冷循环是采用N2 和C1 - C5 烃类混合物作为循环制冷剂。与纯组分制冷剂不同的是,混合制冷剂产生的冷量是在一个连续的温度范围之内,纯组分冷剂产生的冷量是在一个固定的温度上。混合制冷剂的加热86新疆石油天然气2006 年© 1994-2007 China Academic Journal Electronic Publishing House. All rights reserved. 曲线可与被冷却介质的冷却曲线很好地匹配,有效地增加了两者的一致性。同阶式制冷循环相比,混合制冷液化循环具有流程简单、机组少、投资费用低、对制冷剂的纯度要求不高等优点。但单级混合制冷剂循环的能耗要比阶式制冷循环高。因此,为了降低能耗,采用多级混合制冷剂循环。国外技术人员对多级循环特性的评价结果表明,随着级数的增加能耗将有所降低,通过技术经济优化,采用三级混合制冷剂循环较为合理,如图4 所示。图4 典型的三级混合制冷剂循环改进的多级混合制冷剂循环(MRC) 使用了小型铝质板翅式换热器以减少功率消耗。多股流板翅式换热器的温度驱动力小而且能量高度结合,所以其热力学效率很高,这使热股流和冷股流的曲线匹配得很好。在MRC 工艺的基础上又开发出来很多带预冷的混合制冷剂制冷循环工艺,预冷方式有丙烷预冷、混合工质预冷、利用氨吸收制冷来预冷等。丙烷预冷是其中应用比较广泛的一种。APCI公司的丙烷预冷混合制冷剂液化流程(C3PMRC) 广泛应用预国外的大型的LNG工厂中。313 膨胀机制冷循环膨胀制冷循环是通过透平膨胀机进行等熵膨胀而达到降温目的。目前膨胀制冷采用的主要循环有以下三种:(1) 天然气直接膨胀制冷。主要用于原料气有压力能可利用、甲烷含量高的场合。其液化率主要取决于膨胀比,膨胀比越大,液化率也越大。该循环具有流程简单、设备紧凑、投资小、调节灵活、工作可靠等优点。(2) 氮膨胀制冷。它是直接膨胀制冷的一种变型。其优点是对原料气组分变化有较大的适应性,液化能力强、整个系统简单、操作方便;其缺点是能耗比较高,比混合制冷剂循环高40 %左右。(3) 氮气- 甲烷混合膨胀制冷。它是氮膨胀制冷循环的一种改进,与混合制冷剂循环相比较,具有流程简单、控制容易、启动时间短,比纯氮气膨胀制冷节省10 % - 20 %的动力能耗。但是其设计复杂,目前国内还没有成熟的经验。膨胀机循环与阶式循环和混合制冷剂循环相比其优点是,它能够较迅速和简单的启动和停工。当预计生产中有较频繁的停工时,使用此循环是非常重要的,例如在调峰厂。与阶式循环和混合制冷剂循环相比,膨胀机循环的主要缺点是它的功率消耗大。但是,循环的简易性可以弥补高的功率消耗,尤其是在功率消耗不很重要的小型工厂。我国第一座小型的液化天然气生产装置———长庆陕北气田液化天然气示范工程中采用了天然气膨胀制冷循环,取得了较好的效果。4 天然气液化流程的选择本文以新疆呼图壁、彩南、莫北、石西三个油气田所产的天然气为例提出相应的天然气液化方案。四个油气田天然气的参数如表2 所示:表2 四个油气田中天然气的参数油气田名称呼图壁彩南莫北压力(MPa) 3 310～410 4流量(104m3Pd) 150 24 80气体体积分数( %)C1 94147 88131 68197C2 3128 4142 18124C3 C4～ C11 N2 CO2 0 0137 11644. 1 原料气的净化从表1 可以看出,原料气中的酸性气体组分很少,且只含有CO2 。国外很多调峰型天然气液化工厂中,原料气的处理是单独采用分子筛吸附的方法,因为分子筛是根据物质分子的大小进行选择型吸附的,可以同时脱除酸性气体和水分,也使得原料气的净化流程简化。呼图壁、彩南、莫北三个油气田天然气的产量不大,利用分子筛吸附能够满足工艺要求。412 液化工艺的选择三种基本的天然气液化流程中,带膨胀机的液化流程适用于处理量小,有压能可以利用的情况下。陕北油田液化天然气示范工程采用天然气膨胀制冷循环,取得较好的效果。建议对新疆这三处油气田的天然气采用天然气膨胀制冷循环,在膨胀制冷循环的基础上,可以采用氮气或丙烷预冷,减少液化循环过程中的功率消耗。© 1994-2007 China Academic Journal Electronic Publishing House. All rights reserved.

Educational background September 2005 -2009 In July Beijing University of Chemical Technology - Electrical and Mechanical Engineering College - safety engineering undergraduate Majoring in Course: Safety Psychology, security economics, security, systems engineering, security, ergonomics, safety evaluation, safety monitoring and testing techniques, chemical safety engineering, environmental engineering monitoring, chemical equipment, failure analysis, hazardous chemicals, pressure vessel security technology, mechanical drawing, AutoCAD, the application of electrical engineering, chemical engineering principles, engineering mechanics, engineering thermodynamics and so on. Internship experience ■ 2006年9月, school-run factories in the production workshop and conducted a two-month internship metalworking.  to cars, clamp, milling, planing, grinding, welding, casting, forging and other types of operating practice.  familiar with CNC Lathe operation and programming.  the use of AutoCAD and BUAA CAXA software model, and CNC milling, EDM machining of finished products. ■ 2007 years 7 months, in Beijing Yanjing Brewery and Beijing Hyundai Motor Company Internship.  understanding process as well as the beer production process, automated car assembly line.  Learn the factory safety procedures and safety responsibility system.  as a team leader, leading to five members of the contents of internship, interns are preparing contingency plans for one of the two. ■ 2008年10月, in Beijing Yanshan Petrochemical Company internship.  in the ninth Dongfanghong refinery operations in the control room to understand the Department of computer monitor flow.  study to understand atmospheric and vacuum distillation unit refinery, oil storage tank area and polypropylene plant.  Yanhua equipment factory in the understanding of heat exchangers and pressure vessels processing flow.  factory safety equipment to listen to Yanhua Engineer HSE management system regarding business seminars.  served as team leader, field trips and is independent of the completion of factory equipment Yanhua investigate potential hazards analysis. Research Training ■ 2007年12 January calendar when completed independent natural gas dehydration tower model plate design and safety evaluation of internship report. ■ 2008年6 hours and a half calendar independently completed the liquefied petroleum gas storage tank safety evaluation and risk analysis report. ■ 2008 study on 10 years School water boiler room operation at the scene, and served as team leader and lead the team with Safety Check List (SCL), Fault Tree (FTA), the risk of and feasibility study (HAZOP) qualitative and quantitative evaluation of their safety situation. ■ Thesis: Rotor Balancing Exploration Technology Research (ongoing). English proficiency and computer skills Through the National English Test 4 (540 points) and CET (481 points), have good listening, speaking, reading and writing ability, familiar with the relevant professional English. Proficiency in the use of Office business software, AutoCAD mapping software to master the basic operation and VB, C programming language to learn Photoshop, CAM, database. The main internal and external practice September 2005 to July 2008 made between the numerous promotions, and other social part-time tutor. September 2005 to July 2006 Network Center school students served as the backbone of the Office of a member of the technical department the record of the meeting and organize upload FTP, realize information sharing among government departments, to assist in publicizing the "fireworks in March," the capital of Colleges and Universities Network Literature Contest . September 2005 to July 2008 the hospital served as the Student Union, vice minister of the Ministry of Sports, participated in planning the organization of the calendar year of colonel and hospital-grade students Games, assisted in the organization of the calendar year of the hospital gala week. August 2008 Olympic Games in Beijing Workers Stadium as the Olympic Games-time volunteers in charge of the audience seating area ticket consulting, approach and leave the flow, coordination to deal with various emergencies, and always stand fast at their posts, warm smile Services. Hobbies Basketball, swimming, music, movies, literature, news, tourism. You very much look forward to becoming a company, Willing to work with your company through thick and thin, determined to forge ahead and create a better future! Find a job, help is pretty busy, all the points all sent!