乙烯装置急冷系统扩能改造方案分析.pdf

工业技术乙烯工业2 0 2 4,3 6(1)2 8 3 2ETHYLENE INDUSTRY乙烯装置急冷系统扩能改造方案分析宋志琪，马国民，丁少辉，巫廖莎，徐文明（中国石油天然股份有限公司独山子石化分公司，新疆独山子8 3 3 6 9 9）摘要：某百万吨乙烯装置2 0 19 年利用大检修窗口期进行扩能改造，包括新增1台乙烷裂解炉、减黏塔系统、甲苯萃取系统等，以及对相关配套的设备及设施改造，使乙烯生产能力达到115 0 kt/a。总结、分析了2 0 15 年和2 0 19 年乙烯装置2 次检修后的运行情况，以期找准急冷系统运行瓶颈，并针对性制定优化方案。关键词：乙烯装置急冷系统扩能改造长周期运行在乙烯装置中，急冷油、急冷水品质直接关系到乙烯装置的平稳运行和能耗，其运转效果和稳定性对装置有着重要的影响。急冷水乳化会导致稀释蒸汽的品质变差、急冷水以及工艺水换热器的换热效果变差、系统排污量增大、排污油含量超标、系统中压蒸汽补人量增大。因此急冷水、急冷油系统的稳定运行是保障裂解炉和急冷系统安全项目2017-05-29(改造前)2020-06-11(改造后)2019年乙烯装置改造后各原料加工量有明显提升，总加工负荷提升47.1t/h，提高11.1%，乙烯生产能力达到110 0 kt/a。改造前后汽油分馏塔运行参数见表2。2019年乙烯装置扩能改造后，汽油分馏塔负荷增加，虽然裂解气进塔温度高于改造前约10，但由于中部循环和底部急冷油循环撤热明显，其中新增脱丙烷塔塔釜再沸器、工艺水汽提塔塔釜再沸器（新换热器）有效利用中部热量，因此塔上部汽油回流量降低明显，上部液相负荷降低，上部压差小于改造前，中上部操作参数接近设计值。存在的问题：1)汽油分馏塔中上部热负荷虽有所下降，但柴油回流量依然较高，柴油无单独采出外送流程，运行的必要条件。1改造前后急冷系统运行参数对比1.1操作参数表1为某乙烯装置扩能改造前、后加工负荷情况对比。表12 0 19 年乙烯装置扩能改造前、后装置加工负荷石脑油轻烃211.7129.8253.7123.3t/h加氢裂化尾油装置总负荷81.4422.993.0470.0只能与燃料油掺送。2)汽油分馏塔塔釜温度低于设计值，影响稀释蒸汽发生器再沸器传热。改造前后急冷水塔主要运行参数见表3。由表3 可知：急冷水塔的温度及回流量均高于改扩建前,且塔压降增加约1kPa,表明急冷水塔的热负荷大幅增加。存在问题：1)新增1台裂解炉，目前操作工况为8 开1备，当投退炉切换时，9 台裂解炉切人系统，造成急冷水塔蒸汽量增加43 t/h,塔釜温度最高9 1，导收稿日期：2 0 2 2-10-2 3；修改稿收到日期：2 0 2 3-0 8-10。作者简介：宋志琪，男，2 0 17 年毕业于西南石油大学化学工程与工艺专业，现从事乙烯生产操作工作，助理工程师。装置负荷率，%104.9114.8第3 6 卷致急冷水塔长期处于高温状况，应在塔的中下部冷凝的重质组分，装置被带至塔的中上部，可能存在结焦、堵塞的风险，进而造成压降上涨，严重则造成装置停工。2)为控制裂解气压缩机段间pH值,急冷水系统目前pH值维持在8 以上，高温下加剧了急冷水乳化的风险。3）乙烯装置急冷水系统聚结器设计的工艺使表2 2 0 19 年乙烯装置扩能改造前、后汽油分馏塔运行参数项目位置进塔裂解气温度/塔顶中部回流塔釜塔上部压差/kPa塔下部汽油柴油回流量/(th-l)急冷油回流量柴油并入急冷油流量表3 2 0 19 年乙烯装置扩能改造前、后急冷水塔运行参数项目设计值塔顶38.0塔釜83.0温度/顶部回流中部回流压差/kPa塔中上部顶部回流量/(th-l)中部1.2急冷油黏度控制随着轻质原料加工量的逐渐增加，易引起急冷油黏度升高，造成汽油分馏塔塔釜温度降低，稀释蒸汽发生量减少，中压蒸汽补人量增加，因此在扩能改造期间新增减黏塔。塔釜的重燃料油用重项目09-04塔釜急冷油黏度(10 0 )/(mms-l)86.92塔釜急冷油黏度(5 0)/（mms=l)3333宋志琪等.乙烯装置急冷系统扩能改造方案分析设计值改造前（2 0 17-0 5-2 9）188.00(14号炉)224.50179.0(58号炉)106.28110.60120.55123.30210.00180.80全塔最大711.73.0331.0510.412642.0643.9603.006200393改造前2017-05-2935.083.235.034.055.058.85.002.6912889714.7205422燃料油产品泵抽出，一部分通过回流阀返回汽油分馏塔，以维持塔液位；另一部分作为裂解燃料油产品送至界区。增加减黏塔前后汽油分馏塔急冷油黏度取样检测结果见表4。减黏塔工艺流程见图1。表4增加减黏塔前后汽油分馏塔急冷油黏度取样检测结果改造前（2 0 17 年）04-17101.2500029.用温度为8 0，操作压力0.6 MPa，配置2 台工艺水预过滤器（S-2861A/S）和1台工艺水聚结器（V-2 8 3 2）。目前操作温度约8 6，压力1.3MPa,与过滤器滤材不兼容，操作温度过高已造成玻璃纤维中的硅酸盐成分在水介质中发生水解反应,从而降低过滤精度。在预过滤器失效的情况下，大量的固体颗粒穿透预过滤器进人聚结器，致使整个聚结器系统失效。2020-06-1137.7384.635.5862.53.641288520211-072019-12-0650504833991改造后（2 0 2 0-0 6-11)200.50(14,9号炉）189.60(58号炉)103.60113.80185.7063.0385.019555226230改造后2021-03-2236.2385.934.4364.413.4313835 393改造后2020-12-17503712021-03-115072730裂解炉馏出物高压蒸汽急冷油减黏油来自汽油分馏塔高压蒸汽乙烯工业汽油分馏塔急冷器第3 6 卷减黏塔重燃料油外送X过滤器K重燃料油返回汽油分馏塔X燃料油外送泵X图1减黏塔工艺流程示意从表4可知：减黏塔投用后可有效控制汽油分馏塔塔釜急冷油黏度。1.3工艺水水质乙烯装置自2 0 0 9 年投产以来,工艺水系统频繁发生聚合结垢及泄漏问题，工艺水汽提塔以及稀释蒸汽发生器再沸器入口管道经常发生堵塞。对工艺水系统聚合物进行取样分析,其主要组成为聚苯乙烯。经调研国内同行业经验，增加甲苯萃取系统,利用甲苯将苯乙烯等芳香烃从工艺水中萃取分离，甲苯在后续工艺水汽提塔中汽提分离。主要流程为在聚结器入口过滤器（S-2861A/S）上游增加甲苯萃取罐（V2 8 3 4），喷射器（SP J-2 8 0 1)和甲苯工艺水混合器（SPM-2801）的工艺水管道以及返回管道。采用工艺水甲苯萃取技术可有效控制工艺水中油及不饱和烃类，改善工艺水的水质，减少工艺水系统内的油类物质结垢及苯乙烯类聚合物生成量，进而能够确保稀改造前项目2016-12甲苯萃取罐V-2834前181.8甲苯萃取罐V-2834后181.8苯乙烯含量工艺水汽提塔塔釜稀释蒸汽分离器底表6 改造前后工艺水汽提塔压差变化改造前项目2015-10-07工艺水汽提塔压差2.93释蒸汽系统正常运行。急冷系统甲苯萃取单元于2 0 19 年11月1日投用,表5 为检修前后工艺水中苯乙烯含量取样结果。甲苯萃取系统投用后，工艺水汽提塔进水中苯乙烯含量明显下降，同时水质浊度下降明显。改造前，工艺水汽提塔压降逐步上涨，2 0 18 年8 月已增至3 3 kPa,装置被迫切塔更换填料,且降低了加工负荷。改造后开工投用至今，塔压降无明显上涨（见表6）,说明甲苯萃取系统可明显减缓工艺水系统结垢问题。但运行中存在以下问题。1)水系统出现波动时，苯乙烯萃取率仅5 0%，易造成大量甲苯、苯乙烯带人工艺水系统，造成塔内结垢。2）上游聚结器前置过滤器失效，在甲苯萃取单元停用或甲苯中断时无法发挥聚结器的效果。将择机对S-2861及工艺水聚集器进行改造检修。表5 改造前、后工艺水中苯乙烯含量取样结果2017-02139.8139.846.075.464.712017-04-239.45mg/L改造后2018-082019-11-04167.65162.27167.6568.935.053.480.652018-08-06233.002019-11-16154.2376.999.642.07改造后2019-12-062020-02-144.133.262020-06-11158.773.820.050.05kPa2021-03-153.85第3 6 卷1.4蒸汽消耗及排污乙烯装置用于产生稀释蒸汽的主要热量来自回收循环急冷油的余热和中压蒸汽冷凝提供的热量。装置产能由10 0 0 kt/a乙烯提至115 0 kt/a乙烯，急冷油系统热负荷必然增加，为回收急冷油改造前项目2018-09-19装置负荷/(th-)418.7稀释蒸汽压力/MPa0.616稀释蒸汽总流量/(th-l）255.4外补中压蒸汽阀位，%0.6含油污水外送量/(mh-1）114.2根据历年运行情况分析，发现稀释蒸汽发生器再沸器历次检修周期中均出现泄漏，给装置平稳运行带来较大隐患，影响装置加工负荷和乙烯产量。装置在2 0 2 0 年对稀释蒸汽发生器2 号再沸器(E-3012)逐台进行更换，如图2 所示。目前换稀释蒸汽去汽提塔宋志琪等.乙烯装置急冷系统扩能改造方案分析表7 改造前、后稀释蒸汽及排污量变化2018-11-172019-04-04420.1423.20.6100.610258.3244.10.00.075.5864.12热器运行良好；同时为避免稀释蒸汽发生器1号再沸器(E-3011A/B/C)泄漏，保证工艺水系统正常运行，减少稀释蒸汽系统外补中压蒸汽量和连续排污量，装置在稀释蒸汽系统中压蒸汽总管处安装减温器，注人锅炉给水,降低中压蒸汽过热度，目前暂未发现泄漏。稀释蒸汽去裂解炉E-3014-31系统热量，减少中压蒸汽的补人，新增1台稀释蒸汽发生器2 号再沸器（E-3012S），与原E-3012AL并联。表7 为乙烯装置扩建前后稀释蒸汽单元外补中压蒸汽量。改造后2020-02-142020-04-19403.5455.50.6140.611257.2267.59.65.073.3934.17中压蒸汽(MS)2021-03-224650.616266.70.050.78V-3031E-3011中压蒸汽(MS)E3015MSCD工艺水来自蒸汽冷却器V-3031禾稀释蒸汽发生罐；E-3014稀释蒸汽发生器；E-3011/E-3012发生器1号/2 号再沸器；E-3015稀释蒸汽过热器图2 减温水工艺流程示意由锅炉给水泵出口来的锅炉给水在甩头接管进人E-3011A/B/C的温度。线至中压蒸汽补人调节阀PV30044A阀前DN600投用后管道未出现泄漏，投用后稀释蒸汽发管道预留变径三通处，内装减温器。在PV30044A生系统运行平稳，稀释蒸汽压力和温度正常，E阀后新增远传温度热偶，通过TIC30600控制MS3011人口中压蒸汽（MS）温度由2 3 7 下降至A-BFWE-3012文循环急冷油+循环急冷油2稀释蒸汽来自低压给水泵32.218,有效地避免了因MS温度过高造成的热冷两相温差大导致的管束泄漏情况，保证了装置正常平稳运行。严格控制工艺水系统pH值，稀释蒸汽再沸器人口流量计重新配管，提高流量计投用率和准确性。按设计分配各换热器工艺水流量，避免换热器局部超负荷，同时每日取样检查工艺水系统水质，出现异常立即组织排查；制定计划定期对稀释蒸汽再沸器进行反冲，减少垢下腐蚀。2改进措施2.1急冷油系统根据装置现有条件，通过调整汽油分馏塔中部回流流量，进一步降低塔的上部气相负荷，避免柴油组分被带至急冷水塔。同时提高裂解炉急冷器出口温度,降低炉出口急冷油用量，逐渐缓慢提高釜温至18 8 19 0,以进一步降低急冷油泵负荷率。2.2急冷水系统装置通过在大检修期间对聚结器改造：一是增大过滤面积，以适应急冷水高固含量及增大水量(10%)的需求；二是将滤材由现有的玻璃纤维改为环氧树脂浸泡醋酸纤维素,其使用温度可达到13 5,使用效果良好。经计算,按照5 0 t/h稀释蒸汽量（考虑扫线的蒸汽），在夏季裂解炉8 开1备操作工况下，急冷水换热器无任何余量。考虑夏季循环水污垢系数增加及急冷水塔中部换热器（E2 8 11)改造后的偏流情况，增加急冷水塔顶部换热器（E-2812）的00000000000乙烯在线目前，国内首台自主研制的大型螺杆机在福建联合石化芳烃低温热回收装置投用以来，已平稳运行超7 0 0 d,月均直接降低二氧化碳排放超10 0 kt,有效降低二氧化碳排放总量和强度,助力芳烃联合装置节能创效取得新成效。为保障机组持续高效稳定运行，福建联合石化多次组织精干力量进行机组结构改造和性能优化，对该型国产螺杆机密封系统进行升级、盘车器结构进行优化，在减少原料损耗、防止人员误操作的同时，不断挖掘装备潜力，提升效益水平。摘自中国石化报2 0 2 4-0 3-0 1乙烯工业换热能力2 0%。急冷水破乳剂性能差，急冷水存在轻微乳化，急冷水比热下降，热量不足，更换高效的破乳剂，替换目前HK1412C。2.3蒸汽系统解决措施1)在2 0 2 0 年对稀释蒸汽发生器2 号再沸器逐台进行更换，目前换热器运行良好。2)每日取样检查工艺水系统水质,出现异常立即组织排查。3)定期对稀释蒸汽再沸器进行反冲，减少垢下腐蚀。4)结合目前操作工况，合理控制稀释蒸汽汽包连续排污流量不低于7%，减少有害物质聚集。5)精细化控制换热器的热负荷定期对换热器测温测速，避免局部汽化率过大，凝缩倍率提高，造成结焦腐蚀。3结语乙烯装置扩能改造后，急冷单元在调整助剂种类，换热器类型的同时，急冷油系统增加减黏塔，有效降低急冷油黏度；工艺水单元增加甲苯萃取系统,改善水质同时延缓急冷系统腐蚀速率，稀释蒸汽发生器的增加及减温水的投用,能够改善稀释蒸汽系统存在的问题。参考文献：1王吉平.乙烯装置低排放停开工方案探索与实践J.乙烯工业,2 0 18,3 0(3):12-17.0000000000福建联合石化优化国产装备节能创效第3 6 卷ABSTRACTSREVIEW OF SINOPECS ETHYLENE PRODUCTION IN20231Zeng Miaoyang,Zhang Xiaoming,Ma Guofeng,Zhang Wei.Chemical Department of SINOPEC,Beijing,P.C.100728Abstract:The achievement and performance of SINOPEC s ethyleneproduction in 2023 are introduced and analyzed briefly from theaspects of safety and environmental protection,feedstock andoperation optimization,energy saving and consumption reduction,technology research,long-term operation and maintenance,and theobjectives and focus of SINOPECs ethylene production in 2024 areput forward.Key words:SINOPEC;ethylene operation;reviewOVERVIEW OF PETROCHINAS ETHYLENE BUSINESS IN20237Shen Yang,Jiao Lifei,Liu Zhaohui,Liu Xiaozhou.PetroChinaRefining,Chemicals&New materials Company,Beijing,P.C.100007Abstract:This paper summarizes the development of PetroChinasethylene business in 2023,including the ethylene production,ethylene yield,yields of ethylene and propylene,processing lossratio and energy consumption _of its subordinate petrochemicalenterprises,as well as the feedstock optimization,long-termoperation,maintenance,technical modification and technicalmeasures.The_focus of work,concerning long-term optimumoperation of ethylene plants in 2024 is put forward.Key words:PetroChina;ethylene;overviewAPPLICATIONOFDEMULSIFIERAND SCALEINHIBITORINETHYLENEPLANT13Huang Zikun,Wang Zhicheng.SINOPEC-SK(Wuhan)Petrochemi-cal Company Limited,Wuhan,Hubei,P.C.430000Abstract:In recent years,affected by the diversification of rawmaterial to ethylene plant,the emulsification of quench wateroccurred.More and more benzene series remain in the system,leading to serious polymerization in process water system.Thepolymerization of process water not only leads to the blockage ofmultiple heat exchangers in the quench unit,but also may lead tothe shutdown of the quench unit in severe cases,which becomes one.of the main botlenecks for the long-term operation of ethylene plant.A new reagent is used in the quench water system to improve thewater quality and alleviate the emulsification and fouling problems ofthe water system,thus effectively prolonging the operation period ofthe ethylene plant.,Key words:quench water;emulsification;fouling;demulsifer andscale inhibitorCAUSE ANALYSIS AND OPTIMIZATION OF HIGH PRO-PYLENE CONTENTAT BOTTOM OFPROPYLENE RECTI-FICATIONTOWER18Lai Xijiang,Wang Junbin,Zhang Lei,Huang Chaobo,ZhangYanglong.PetroChina Dushanzi Petrochemical Company,Dushanzi,Xinjiang,P.C.833699Abstract:With the increase in the load of propylene rectificationtower in a 220 kt/a ethylene plant,the propylene loss in thecirculating propane at the bottom of tower reached 10%.In order toreduce the propylene loss at the bottom of propylene rectificationtower,Aspen Plus was used to establish a propylene rectificationtower model with the operation data of propylene rectification tower,and the current operation of the propylene rectification tower wasanalyzed and studied.By identifying the deviation points betweenthe simulation data and the actual operating parameters,theoperation of propylene rectification tower was adjusted andoptimized,so as to reduce propylene loss at the bottom of tower,increase propylene production and achieve the purpose of improvingquality and efficiency.Key words:propylene rectification tower;simulation;optimizationCAUSE ANALYSIS OF VIBRATION OF SILENCER ANDPIPELINEAT OUTLET OF RECYCLEGAS COMPRESSORINBUTADIENEUNITAND THE MODIFICATION21Zhang Xiaowei,Feng Min,Sheng Nan,Ju Tao,Jiang Feng.PetroChina Dushanzi Petrochemical Company,Dushanzi,Xinjiang,P.C.833699Abstract:To solve the vibration problem of the silencer and pipelineat the outlet of screw compressor in a chemical company,the gasETHYLENEINDUSTRYStarted Publication in 1989,Quarterly.Mar:2024 Vol.36 No.1 Total 137thpulsation and pipeline vibration of the existing exhaust pipe wasanalyzed,the main causes of the pipeline vibration were identifiedcombined with the measured data of pipeline vibration on site,andsome corresponding modification measures were put forward.Somereasonable vibration elimination measures were taken such asreplacing the silencer with three-chamber impedance compoundsilencer,revamping the exhaust pipe,installing pipe supports andreinforcing the thermocouple branches.After modification,thepressure unevenness at each point inside the exhaust pipe can meetthe requirements of API 619,and the gas pulsation decreased by72%on average.The first-order natural frequency of the exhaustpipe system increased from 4.572 Hz to 8.862 Hz,and the high-order natural frequency was 10%away from the compressorexcitation frequency.The maximum vibration of the silencerdecreased by 64%to 32 mm/s and the maximum vibration of theoutlet pipe decreased by 87.5%to 10 mm/s compared with thosebefore the modification,proving the effectiveness of the modificationmeasures.Key words:screw compressor;silencer;pipeline vibration;mea-sureCAUSE ANALYSIS AND PREVENTIVE MEASURES FORLEAKAGE OF TUBE BUNDLESOF STEAM-WATER HEATEXCHANGERS24Zhang Changsong,Huang Chaobo,Li Wenting,Du Zhiqi,LeiQian.PetroChina Dushanzi Petrochemical Company,Dushanzi,Xin-jiang,P.C.833699Abstract:To solve the leakage of steam-water corrugated-tube heatexchanger in hydrogen plant,the causes of the leakage of heatexchanger tube bundle were analyzed combined with the specificoperating conditions,the analysis results were obtained combinedwith the actual inspection report based on the corrosion mechanismof corrugated tubes in the environment of chlorine-containingmedium,and some specific preventive measures were developedcorrespondingly based on the cause analysis.The corrosion hazardswerecompletely eliminated throughheat exchange tubemodification,the operating cycle of the heat exchanger wasextended,and the long-term operation of the heat exchanger wasensured.Key words:steam-water heat exchanger;corrosion;leakage;improvementCAPACITY EXPANSION SCHEMES OF QUENCH SYSTEMINETHYLENEPLANT28Song Zhiqi,Ma Guomin,Ding Shaohui,Wu Liaosha,Xu Wenming.PetroChina Dushanzi Petrochemical Company,Dushanzi,Xinjiang,P.C.833699Abstract:In 2019,the capacity of a megaton ethylene plant wasexpanded in the overhaul window period,including the installationof an ethane cracking furnace,a viscosity reducing tower system anda toluene extraction system as well as the transformation of relatedsupporting equipment and facilities,so that the capacity reached1.15 million tons per year.This paper analyzes and summarizes theoperation of the ethylene plant after two overhauls in 2015 and 2019respectively,in order to find out the operation bottleneck of quenchsystem and formulate targeted optimization plans.Key words:ethylene plant;quench system;capacity expansion;long period operationAPPLICATION OF CFD TECHNOLOGY IN THE RE-SEARCH ON PIPING LAYOUT FOR RECYCLING DECOK-ING EFFLUENT TO FIREBOX OF LARGE-SCALE CRACK-INGFURNACE33Lin Jiangfeng,Xiao Jia.SINOPEC Engineering Incorporation,Bei-jing,P.C.100101Abstract:Recycling decoking effluent to firebox of cracking furnaceis one of the effective measures to reduce pollutant emissions fromthe cracking furnace,and the piping layout for recycling decokingeffluent to firebox has a significant impact on the decoking effect.This article uses CFD technology to numerically simulate the pipinglayout for recycling decoking effluent to firebox.RNG k-8turbulence model is used for the simulation,and the wall functionStandard Wall Fn is used to correct the near wall flow.Thecalculation results indicate that a reasonable piping layout canensure the even entry of decoking effluent into the firebox without