最新Lummus公司分析与乙烯厂压缩机实际情况.doc

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1、Four short words sum up what has lifted most successful individuals above the crowd: a little bit more.-author-dateLummus公司分析与乙烯厂压缩机实际情况Lummus公司分析与乙烯厂压缩机实际情况Lummu公司裂解气压缩机结焦分析报告与抚顺乙烯厂裂解气压缩机实际运行情况摘要：ABB Lummus Global 2001 发布的裂解气压缩机分析报告 与抚顺乙烯厂GB-201 裂解气压缩机实际生产情况2010的对比。关键词：Lummus 抚顺乙烯 压缩机 结焦1、 介绍 Lummu

2、s 公司分析：乙烯裂解气压缩系统在投入运行后被证明有结焦情况，在Lummus 公司的客户记录上50的工厂会引发结焦在压缩机和冷却器上，几乎所有的裂解气压缩机用户都报告过结焦情况。裂解气压缩机结焦成为压缩机用户计划检修的一个重要的原因。抚顺乙烯厂用户实际情况：在2005年4月和2008年8月 抚顺乙烯装置计划检修中，都发现裂解压缩机有结焦情况，并进行GB-201注水改造，湿蒸汽清洗。2、原因Lummus 公司分析：裂解气压缩机结焦产生于聚合反应和缩合反应，产生的聚合物会附着在压缩机和冷却器内部表面上。聚合物主要产生于裂解气组分的反应，沉淀物主要来自于碱洗塔塔，沉淀物会影响压缩机迷宫密封。温度 压

3、力 停留时间 都影响压缩机叶轮的结焦程度。原料中一些不纯的组分会影响结焦率，原料中含有氧 或双烯烃 会影响 裂解系统的结焦。所以在一些设计相同的工厂，原料的组分不同会引起不同的结焦率。抚顺乙烯厂用户实际情况：原料中用下游自产的循环乙烷抚顺乙烯厂在2008年计划检修中，发现GB-201 出口各冷却器上都出现过结焦，并进行了冲洗清焦工作。裂解气压缩机五段出口温度都控制在90度左右 入口温度都控制在30 度左右当碱洗塔水洗段液位出现波动的时候，和 各段碱循环不到32 t/h，在实际操作中要迅速找到原因，并及时进行处理。DA-203塔碱洗塔水洗段液位控制在50，每段循环量40t/h3、危害Lummus

4、 公司分析：结焦发生会影响压缩机内部组件的性能。结焦会影响压缩机内部元件表面粗糙度。影响叶轮的特性。改变气体在流道中的角度，这种影响会直接影响压缩机的效率。在现实中，这种损失反应在压缩机的转速提高上和能量的消耗上。压缩机处理相同的东西需要更高的转速由透平提供。迷宫密封的原理和结焦的影响 迷宫密封的原理是被密封介质在通过曲折迷宫的间隙时产生节流效应而达到阻漏的目的。结焦会在间隙间产生，影响密封的效果，使物料或蒸汽泄露，这样的泄露会进一步加大能源的损失。会影响压缩机的处理能力。结焦的压缩机在相同的工况下会消耗更高的能量。一个产量为100万吨每年的工厂，在能耗每年的损失在10万美元，这样的损失会随着

5、结焦程度的增加而加大。当压缩机转速提不上去，或者透平到达极限的时候，这时候吸入压力会增加，但原料的数量不变，导致吸入压力升高，乙烯或丙烯的收率就会降低。这样在能源方面的损耗和原料的利用率上每年的损失会高达百万美元。结焦对压缩机的元件的影响结焦的聚合物是一种粘性物质不会损坏压缩机，但结焦产生的重质烃和焦碳会损坏压缩机的密封 和转动轴。抚顺乙烯厂用户实际情况：抚顺乙烯厂裂解气压缩机GB-201在2010年运行中出现结焦情况，裂解炉在60吨的时候 ，压缩机一段吸入压力高于 50kpa设定值，最高时达到70 kpa ,透平的转速在8200，HPV阀门开度为100 ，透平转速提高 不上去。GB201 S

6、S蒸汽量为100H/T ，GB501 HS量为45T/H GB-601HS量为25T/H.消耗蒸汽量对比以前的数据 都有大幅度的增长。乙烯 的瞬时产量为19T/H 丙烯的瞬时产量为 8T/H 压缩机的结焦上 都影响在原料的利用效率上 双烯收率上 ，蒸汽的用量上。在抚顺乙烯厂2008年计划检修中，发现GB-201裂解气压缩机迷宫密封 ，叶轮出口，转动轴 都有不同程度的结焦。在日常操作中，裂解气压缩机轴振动出现过高情况。ZI-92204、测量与监测Lummus 公司分析：我们如何测量结焦的程度 和在应用处理结焦的方法，如何测量这种方法的效果。测量结焦程度直接方法最直接的方法就是在检修的时候 观察结

7、焦的程度和范围。如果应用完处理的结焦方法后，在下次检修时发现没有结焦，说明这种方法很成功。但这样的情况很少发生。Lummus公司的关于压缩机效率的公式。通过对裂解气压缩机各个参数的具体计算，能精确的算出压缩的进行的情况，及结焦。具体见Lummus分析报告。 轴承温度，轴承位移，轴承振动都提供了对压缩机持续的监测。但它们不能直接确定压缩机是否结焦。轴承振动高可能是叶轮的不平衡。轴承振动可能是压缩机结焦的早期信号。油质 在油箱中如果聚合物聚集情况过多，也可能是压缩机结焦的显示，需要对油质进行具体的分析确定。抚顺乙烯厂用户实际情况：抚顺乙烯厂在2008年检修中 对GB-201 进行拆装 发现 叶轮

8、和机壳上都有结焦物。抚顺乙烯厂通过 轴振动 轴位移 温度 在线监控 ，对压缩机状态起到了最及时的了解。裂解气压缩系统 轴振动 ZI-9220出现高报情况。TI-9223轴承温度出现高报情况在现在生产运行中。乙烯厂分析站定期对GB-201所用46号润滑油进行分析检查。5、解决方法Lummus 公司分析：操作环境的改变会阻止结焦反应的发生下面是处理结焦的几个原则。1较低温度会降低结焦反应率2 添加抗垢剂会阻止聚合物黏附在压缩机的表面上。3 改变压缩机表面的特性可以改变聚合物的黏附。温度许多的的聚合反应会成倍的增长，如果 温度升高10度 到20度，所以在设计和建设工厂的中，怎么样降低温度会对工厂产生

9、的效益具有重要的作用。下面三步会有效地控制裂解气压缩机的温度：1 设计5段的裂解气压缩机会比 4段 的 温度低，每段能有效的降低20度。2 冷却压缩机的吸入物料 可以降低压缩机的吸入温度。3 向压缩机每段注水，当水汽化的时候可以有效的降低裂解气的温度。添加剂使用有效的添加剂可以抑制聚合反应的发生，有效地抑制了结焦。表面特性压缩机内部部件的表面特性，可以直接影响聚合物是不是粘在上面。一些强力润滑涂料许多供货商可以提供，它可以有效的 的抑制聚合物的黏着度，提供了很好的保护对于腐蚀作用和侵蚀作用。这些涂料可以应用在转子，内壳壁上，入口和出口壁上，还有隔板上。许多工厂都在应用后得到了很好的效果。抚顺乙

10、烯厂用户实际情况：1抚顺乙烯厂在2005年4月进行裂解气压缩机注水改造，将原来的洗油系统 改为注水系统。GB-201机组原设计用清洗油来防止流道内结焦，清洗油在各段入口管道和各级弯道处注入，共有11个注入点，现在改为注水，能更有效的防止结焦。实际生产中通过调节GB_201各段注水量，注水量控制在0.9T/H以下，控制GB-201各段出口温度在90度以下，通过调节段间换热器冷却水的量，控制压缩机入口温度在30度，有效的抑制结焦。2抚顺乙烯化工厂于2003年三月开始注入压缩机抗垢剂，注入点时洗油注入泵GA-206 A-F上，型号为 HK-28抗污垢剂，注入量为60吨每小时 起到了很好的抑制结焦的效

11、果。3抚顺乙烯厂还在2008年10月份对透平进行了湿蒸汽清洗的清焦的工作。在湿蒸汽清洗后，GT-201 GT-501状态，蒸汽利用效率上明显得到提高，GB-201一段吸入压力得到了很好的控制。原料利用率上得到了提高。5、结论提高裂解气压缩机的效率对乙烯生产效益是非常重要的，能量的损耗都伴随着巨大的经济损失。对结焦的监测，处理对节约能量，保持装置长周期运行，有着极为重要的意义。在实际生产中，下面是推荐的l 注水 降低 压缩机排出温度l 考虑注洗油l 常规的监测 轴承温度 轴承位移 温度l 裂解气压缩机的效率与蒸汽量的监控l 降低原料中的氧含量 双烯的含量l 压缩机油中聚合物的含量6、附件Over

12、view of Cracked Gas Compressor Fouling:Theories and PracticesBy: Stephen De Haan, ABB Lummus GlobalBrian K. Sullivan, ABB Lummus GlobalPresented at: 2001 Spring National MeetingApril 23-26, 2001, Houston, TXOVERVIEW OF CRACKED GAS COMPRESSOR FOULING:THEORIES AND PRACTICESABSTRACTMost cracked gas com

13、pressors foul as they operate. The build up of polymer on the rotor and other internals results in increased frictional losses and altered flow patterns. These changes in turn cause losses in efficiency and head produced as well as the potential for unbalancing the rotor and damaging the seals.Incre

14、asing the compressor speed and steam turbine output can compensate for the losses in efficiency and head produced. However, once the capacity limit of the steam turbine has been reached or the compressor speed can no longer be increased, the throughput of the compressor will decline. In any event, t

15、he energy use per ton processed will increase with increasing fouling. The foulant is generally a polymeric material. The fouling mechanism is not completely understood, but it appears to be a strong function of both compressor temperature and foulant precursor and promoter concentrations. The foula

16、nt precursors include styrene, indene, butadiene, and cyclopenta diene. Compounds containing oxygen promote the polymerization reaction.The fouling reaction is thought to occur on the compressor surfaces resulting in the deposition of a layer of polymer.Several methods are employed alone and in comb

17、ination to control fouling: Wash Oil Addition Water Injection Inhibitor Injection Coating of the Compressor InternalsThis paper will provide an overview of the problem and solution methods.IntroductionThe cracked gas compression systems of ethylene plants are prone to fouling. Based on our experienc

18、e, more than 50% of the plants incur substantial fouling in the compressor, aftercoolers, or both. Interestingly, nearly all of the gas cracking plants reported problems with fouling.In addition, fouling of the cracked gas compressor (CGC) and intercoolers has been cited as a prime reason for the sc

19、heduling of plant turnarounds by a number of operators.CausesFouling of the cracked gas compressor is most often the result of polymerization andcondensation reactions. The predominant reactions involve materials present in the cracked gas that polymerize and deposit on the internal surfaces of the

20、compressor and aftercoolers. Condensation reactions can produce heavy materials that also form deposits.Deposits can also result form the carryover of caustic from the caustic tower. These deposits are of a completely different type and result from poor performance of the caustic tower and the wash

21、section. Caustic carryover doesnt form polymers but will attack the labyrinth seals. (Many of the plants have changed from aluminum to polymer labyrinths to avoid this problem.)Finally, the reactions are influenced by the presence of promoters and catalysts. Often undetected impurities contained in

22、the feedstocks play an important role in determining the rate of fouling. Compounds containing oxygen or peroxides help promote fouling in the cracked gas system and throughout the plant. Oxygen and other spurious compounds can be introduced into the plant in the fresh cracking feedstocks or in recy

23、cles from downstream units. The variability in feed impurities, especially oxygenated compounds, may be a reason that similarly designed plants cracking similar feeds sometimes experience significantly different fouling rates.ConsequencesAs fouling occurs, it roughens the internal surfaces of the co

24、mpressor, alters the cross sectional area and angles in the flow path, and impacts the impeller characteristics. These changes lead to increased frictional losses and altered aerodynamics. The result is a reduction in the efficiency and head produced. In practice, this loss manifests itself as an in

25、crease in operating speed and power consumption. To maintain the operating pressures, the compressor speeds up requiring more power to be delivered by the steam turbine or variable speed motor.Measurement and MonitoringVibration analysis, bearing temperatures, torque meters, and other measurements a

26、llow continuous monitoring of the compressor operation. None of these provides a direct unambiguous measurement of fouling. Increased vibration can result from fouling deposits that imbalance an impeller but could also result from other mechanical problems unrelated to fouling. In addition, vibratio

27、n is seldom an early warning sign of fouling.CuresAs with any unwanted reaction, CGC fouling is inhibited by changing the operatingenvironment. The methods for combating CGC fouling fall into four basic categories:1. Reducing temperature to reduce reaction rates2. Adding solvents to prevent polymers

28、 from adhering once formed3. Changing the surface characteristics of the compressor to prevent the polymerfrom adhering4. Adding chemical species to prevent reactions, or terminate polymer chainsConclusionThe benefits of reducing efficiency loss in cracked gas compressors will continue to grow. As e

29、thylene plants expand to larger and larger capacities each percentage point loss will carry with it a greater monetary loss. Monitoring, measuring, and counteracting the effects of fouling will save energy and could extend plant run length between turnarounds and improve end of run plant capacity. A

30、lthough the practices discussed in this paper for prevention of cracked gas compressor fouling are generally accepted, they do not always work in every situation. They should be used as a guideline to explore what works best for an individual plant, not as a hard set of rules. In summary, the follow

31、ing practices are recommended:For all plants: Avoid entrainment in the cracked gas compressor knockout drums Regularly monitor: Thrust loads and vibrations Bearing temperatures Cracked gas compressor efficiency and head Casing drain purge oil for polymer content Feed streams and external recycles for oxygenates Production of fouling precursors in the furnace effluent If an accurate analysis shows a significant loss in efficiency is still occurring, consider: Use of anti-foulant and dispersant chemical additives Intermittent wash oil injection to flush the system-