聚乙烯工艺描述英文.doc

UNIPOL PE Process DescriptionUNIPOL PE工艺描述TABLE OF CONTENTSPROCESS DESCRIPTION1.1Contract Plant Composition1.1.1PE Process Unit1.1.2Supporting Facilities1.1.3Auxiliary Facilities1.2Process Introduction1.2.1Description of PE Process Unit1.2.2Description of Supporting Facilities1.2.3Description of Auxiliary Facilities目 录工艺描述1.1 装置组成 1.1.1 PE 工艺单元 1.1.2 配套设施 1.1.3 辅助设施 1.2 工艺介绍 1.2.1 PE 工艺单元描述 1.2.2 配套设施描述 1.2.3 辅助设施描述1.1Contract Plant CompositionThe Contract Plant produces 300,000 TPY of pelleted Linear Low, Medium, and High Density Polyethylene from ethylene, which may involve the addition of a comonomer (butene-1 or hexene-1) for some Products. The Contract Plant Battery Limits is represented in the diagram provided in Attachment 11 of this Appendix. The Contract Plant consists of the following systems.1.1 合同装置组成本合同装置是用乙烯为单体，可能会引入丁烯-1 或己烯-1 为共聚单体来生产高、 低、中密度聚乙烯树脂的装置，产能为30 万吨/年。合同装置界区范围见本附件的附录1- 1。本合同装置由下列系统组成：1.1.1PE Process UnitThe PE Process Unit utilizes Univation Technologies UNIPOL PE Process, a low pressure gas phase polymerization process, and includes the following process systems:Raw Material Supply and PurificationEthylene PurificationReaction (includes catalyst handling and feeding)Resin DegassingVent RecoverySeed Bed SystemResin Additive HandlingPelleting1.1.1 PE 工艺单元 PE 工艺单元采用 Univation 技术公司的 UNIPOL 聚乙烯技术，这是一种低压气相聚合工艺，包括下列工艺系统： -原料供给和精制 -乙烯精制 -反应 （包括催化剂处理和进料） -树脂脱气 -排放气回收 -种子床系统 -树脂添加剂处理 -造粒1.1.2Supporting FacilitiesThe Supporting Facilities for the PE Process Unit include the following process systems:Resin Handling System1.1.2 配套设施 PE 工艺单元的配套设施包括下列系统： -树脂处理系统1.1.3Auxiliary FacilitiesThe Auxiliary Facilities for the PE Process Unit include the following process systems:Steam and Condensate Recovery SystemFlare SystemsWaste Water Collection and Pretreatment SystemUtility Distribution System1.1.3 辅助设施 PE 工艺单元的工艺辅助设施包括下列系统： -蒸汽和冷凝水回收系统 -火炬系统 -废水收集和预处理系统 -公用工程配送系统1.2Process IntroductionThe design of the PE Process Unit will incorporate the latest UNIPOL PE Process Know-how.1.2 工艺介绍 山西焦化聚乙烯装置的设计将采用最新的UNIPOL PE 工艺技术。 1.2.1Description of the PE Process UnitThe PE Process Unit comprises a number of process systems, which are described in detail in the following sections:Raw Material Supply and Purification (Part 1)Ethylene Purification (Part 2)Reaction (Part 4)Resin Degassing (Part 5A)Vent Recovery (Part 5B)Seed Bed System (Part 5E)Resin Additive Handling (Part 6)Pelleting (Part 7)Process Flow Diagrams (PFDs) that represent these process systems are provided in Attachment 12 of this appendix.All of the equipment described in the following process description is included in the preliminary equipment list provided in Appendix PE 工艺单元描述 PE 工艺单元由一系列工艺系统组成，下面对这些系统进行详细描述： 原料的供应和精制 （第1 部分） 乙烯的精制 （第2 部分） 反应 （第4 部分） 树脂脱气 （第5A 部分） 排放气回收 （第5B 部分） 种子床系统 （第5E 部分） 树脂添加剂处理 （第6 部分） 造粒 （第7 部分） 工艺流程图 （PFD）附于本附件的附录1-2。 下面工艺描述中涉及的所有设备见附件5 中的初步工艺设备清单。 Raw Material Supply and Purification (Part 1)Nitrogen and hydrogen are delivered to the Contract Plant Battery Limits by pipeline.Comonomers, butene1 and hexene1, and Induced Condensing Agent (ICA), isopentane, are supplied to the Contract Plant by pipeline. It has been assumed that sufficient storage capacity is available from the Outside Battery Limits (OSBL) for butene1, hexene1, and ICA.Cocatalyst alkyl is received in shipping containers for use directly in the PE Process Unit.Comonomer PurificationA common purification system is provided for the two comonomers - butene1 and hexene1. Liquid comonomer from the Battery Limits is fed directly into the Comonomer Degassing Column (C1008). The column, which is mounted on the Comonomer Surge Tank (C1007), is equipped with water cooled Comonomer Condenser (E1009) and steam heated Comonomer Reboiler (E1010). A small stream of overhead gas, containing stripped light gas contaminants vents to the flare. The bottom product from the Comonomer Surge Tank passes through Comonomer Cooler (E1011). The coolers primary purpose is to provide adequate NPSH for the Comonomer Charge Pump (G1002 or G1003, an installed spare). The Comonomer Charge Pump boosts the comonomer pressure to approximately 2,861 kPag (415 psig) for flow into the Reactor. From the Comonomer Charge Pump, comonomer flows through the Comonomer Dryer (C1004 or C1005) to remove water and other polar impurities from the comonomer stream by physical adsorption. The molecular sieve beds require periodic regeneration with hot nitrogen. The spare Comonomer Dryer is used while the other is being regenerated, thus allowing uninterrupted comonomer flow.Nitrogen PurificationNitrogen from the Battery Limits passes through the Nitrogen Preheater (E1108) before entering the Nitrogen Deoxo Vessel (C1109 or C1111). The Nitrogen Deoxo Vessel contains a fixed bed of free copper catalyst which removes oxygen from the nitrogen stream by oxidation of copper to copper oxides. The catalyst bed requires periodic regeneration with a stream of hydrogen diluted in hot nitrogen. Nitrogen leaving the Nitrogen Deoxo Vessel is fed to the Nitrogen Dryer (C1112). The Nitrogen Dryer contains molecular sieves which remove water and other polar impurities from the nitrogen stream by physical adsorption. The molecular sieve bed requires periodic regeneration with hot nitrogen. The spare Nitrogen Dryer is used while the other is being regenerated, thus allowing uninterrupted nitrogen flow.High pressure purified nitrogen is utilized in the Reaction System, while low pressure purified nitrogen is supplied to various places throughout the PE Process Unit. Purified nitrogen to be compressed for use in the Reaction System is taken from the outlet of the Nitrogen Dryer. The pressure is boosted by Nitrogen Compressor Package (K1102) to a pressure of about 3,309 kPag (480 psig). The high pressure purified nitrogen then passes through Purified Nitrogen Filter (Y1114) and flows on to the Reaction System.Hydrogen PurificationHydrogen supply from the Battery Limits is preheated in the Methanator Heater (E1204) before entering the Methanator (C1205). The Methanator contains a fixed bed of catalyst which converts carbon monoxide and carbon dioxide in the presence of hydrogen to form methane and water. Hydrogen leaving the Methanator is cooled in the Methanator Aftercooler (E1206) to approximately 40 deg C and is fed to the Hydrogen Dryer (C1207). The Hydrogen Dryer contains molecular sieves which remove water from the hydrogen stream by physical adsorption. The molecular sieve bed requires periodic regeneration with hot nitrogen. The Hydrogen Dryer is bypassed while being regenerated, thus allowing uninterrupted hydrogen flow.Hydrogen from the Hydrogen Dryer is fed to the Reaction System or to the deoxo vessels within the Purification System.ICA PurificationThe UNIPOL PE Process uses isopentane as an Induced Condensing Agent (ICA) within the Reaction System to enhance heat removal. Isopentane from the Battery Limits is fed directly to the ICA Degassing Column (C1421). The column, which is mounted on the ICA Surge Tank (C1406), is equipped with water cooled ICA Condenser (E1422) and steam heated ICA Reboiler (E1415). A small stream of overhead gas, containing stripped light gas contaminants is vented to flare. The bottom product from the ICA Surge Tank passes through the ICA Cooler (E1423). The primary purpose of the cooler is to provide adequate NPSH for the ICA Charge Pump (G1412 or G1413, an installed spare). The ICA Charge Pump boosts ICA pressure to approximately 3,137 kPag (455 psig) for flow into the Reactor. From the ICA Charge Pump, the ICA flows through the ICA Dryer (C1419 or C1420) to remove water and other polar impurities from the ICA stream by physical adsorption. The molecular sieve beds require periodic regeneration with hot nitrogen. The spare ICA Dryer is used while the other is being regenerated, thus allowing ICA flow to continue through the ICA Purification System.AlkylAdditive T2, an alkyl, is used in Ziegler-Natta catalyzed polymerization and is considered to be a hazardous material in some locations because of its reactive nature. Purified nitrogen is used to pressure the alkyl from the shipping container to the T2 Feed Pot (C1505) and then to the T2 Charge Pump (G1503 or G1504, an installed spare). These pumps pressure the alkyl to approximately 3,137 kPag (455 psig) for feed to the Reaction System.All vents from the Additive T2 System are routed to the Seal Pot (C1502) and combined with mineral oil to produce a less reactive solution. Periodically, the Seal Pot contents are drained to a disposal tank for disposal by an offsite disposal contractor.Mineral oil is pumped from supply drums by Mineral Oil Drum Pump (G1514) to the Seal Pot for dilution of alkyl. Alternately, the Mineral Oil Drum Pump may be used to transfer mineral oil from the supply drums to the Mineral Oil Blow Tank (C1512). Mineral oil from the Mineral Oil Blow Tank is used for flushing the Additive T2 System for maintenance.原料的供应及精制 （第1 部分） 氮气和氢气由管道输送至装置界区内。 共聚单体 （丁烯-1、己烯-1 ）及诱导冷凝剂 （ICA） （异戊烷）由界区内的配套设施提供。假定装置界区外有足够的丁烯、己烯及诱导冷凝剂 （ICA）储存。 助催化剂烷基铝用钢瓶直接运至PE 工艺单元。 共聚单体的精制 两种共聚单体丁烯-1 和己烯-1 共用一个精制系统。来自界区的液相共聚单体直接送入共聚单体脱气塔 （C-1008 ）。脱气塔位于共聚单体缓冲罐 （C-1007 ）之上，塔顶有一个水冷的共聚单体冷凝器 （E-1009）使共聚单体冷凝，塔底有一个蒸汽加热的共聚单体再沸器 （E-1010 ）使共聚单体汽化。塔顶脱除的少量的轻组分塔顶气被排放到火炬。共聚单体缓冲罐的底部产品由共聚单体冷却器 （E-1011）冷却。冷却器的主要目的是为共聚单体进料泵 （G-1002 或 G-1003，其中一个是在线备用泵）提供足够的有效气蚀余量。共聚单体进料泵使共聚单体增压至大约2861kPag(415psig)后进入反应器。来自共聚单体进料泵的共聚单体进入共聚单体干燥器 （C-1004 或 C-1005 ），通过物理吸收作用除去共聚单体物流中的水分和其它极性杂质。分子筛床层需要用热氮气定期再生。当一个共聚单体干燥器进行再生时，就启用备用的共聚单体干燥器，这样可使共聚单体不间 断地流入反应系统。 氮气的精制 从界区来的氮气在进入氮气脱氧罐 （C-1109 或 C-1111 ）之前在氮气预热器 （E-1108）中进行预热。氮气脱氧罐含有一个游离铜催化剂的固定床，通过将游离铜氧化成氧化铜而除去氮气中的氧气。催化剂床需要用含有少量氢气的热氮气进行定期再生。离开氮气脱氧罐的氮气进入氮气干燥器 （C-1112 ）。氮气干燥器内设有分子筛，通过物理吸收作用除去氮气中的水分和其它极性杂质。分子筛需要用热氮气定期再生。一台氮气干燥器再生时，另外一台备用干燥器启动运行，以保证氮气持续地流入反应系统。 高压精制的氮气用于反应系统，而低压精制的氮气供给整个 PE 工艺单元各个不同地方使用。氮气干燥器的出口的精制氮气经过压缩后即可供反应系统使用。精制氮气由氮气压缩机 （K-1102 ）增压至大约 3309 kPag(480psig) 的压力后经由精制氮气过滤器 （Y- 1114）进入反应系统。 氢气的精制 由界区来的氢气进入甲醇转化器加热器(E-1204)预热后，进入甲烷转化器(C-1205)。甲烷转化器内有固定的催化剂床，在氢气的作用下，将一氧化碳和二氧化碳转化成甲烷和水。从甲烷转化器出来的氢气在甲烷后冷器(E-1206)中冷却到大约 40 摄氏度后，进入到氢气干燥器(C-1207)。氢气干燥器中的分子筛可以通过物理吸附的作用，将氢气中的水脱除。分子筛需要使用热氮进行周期性的再生。再生时，氢气干燥器的旁路会打开，以保证氢气连续地流入反应系统。 从氢气干燥器出来的氢气送入反应系统或进入精制系统内的脱氧罐。 ICA 的精制 UNIPOL PE 工艺采用异戊烷作为诱导冷凝剂以增强反应系统内的除热速率。来自界区的异戊烷直接进入 ICA 脱气塔 （C-1421 ）。此塔安装在 ICA 缓冲罐 （C-1406 ）之上，塔顶配有水冷的 ICA 冷凝器 （E-1422）使异戊烷冷凝，塔底有一个蒸汽加热的 ICA 再沸器 （E-1415）使异戊烷汽化。含有脱除的轻组分的一小股塔顶气被排放到火炬。从 ICA缓冲罐底部出来后，进入 ICA 冷却器 （E-1423）。冷却器的主要目的是为 ICA 进料泵 （G-1412 或 G-1413，其中一个是在线备用泵）提供足够的有效气蚀余量。ICA 进料泵使 ICA 增压至大约3137kPag (455psig) 后进入反应器。被送入反应器之前，ICA 要经过ICA 干燥器 （C1419 或 C-1420 ）。ICA 干燥器利用分子筛通过物理吸附的方式除去其中的水分和其它极性杂质。分子筛床层需要用热氮气定期再生。当一个 ICA 干燥器进行再生时，就启用备用的ICA 干燥器，这样使ICA 连续地流入反应系统。Ethylene Purification (Part 2)Ethylene from the Battery Limits passes through the shell of the Ethylene Interchanger (E2105) where it is interchanged with ethylene from the Ethylene CO Removal Vessel (C2107). The warm ethylene then passes through the Ethylene Preheater (E2106) where it is heated to 100 deg C before entering the Ethylene Deoxo Vessel (C2109) and then the Ethylene CO Removal Vessel. The Ethylene Preheater is used to achieve the final temperature before entering the Ethylene Deoxo Vessel and for initial heating on plant start-up.The Ethylene Deoxo Vessel contains a fixed bed of free copper catalyst which removes oxygen from the ethylene stream by oxidation of the copper to copper oxides. This bed requires periodic regeneration with a stream of hydrogen diluted in nitrogen.The Ethylene CO Removal Vessel contains a fixed bed of a copper based adsorbent. This bed requires periodic regeneration with a stream of oxygen diluted in nitrogen.Ethylene, after leaving the Ethylene CO Removal Vessel, is cooled to approximately 40 deg C in the Ethylene Interchanger before passing through the Ethylene Dryer (C2112 or C2113). The Ethylene Dryers contain molecular sieves and activated alumina, which remove carbon dioxide, water, and other polar impurities from the ethylene stream by physical adsorption. The Ethylene Dryer requires periodic regeneration with hot nitrogen. The spare Ethylene Dryer is used while the other is being regenerated, thus allowing uninterrupted ethylene flow to the Reaction System.Regeneration of Part 1 and Part 2 Purification BedsThe various purification beds within Part 1 and Part 2 are regenerated periodically. The regeneration cycles are controlled with timers and logic interlocks. Valving is performed manually in the field.Nitrogen from the supply header enters the Regeneration Nitrogen Heater (E2114) on flow control. The nitrogen is heated by this electric resistance heater to the required temperature for regeneration of the regenerable purification beds in Part 1 and Part 2. The hot nitrogen flows to the selected bed through distribution piping.The cooling and preload steps of the regeneration cycle for all dryers use low pressure unpurified nitrogen. The vent stream from the purification bed being regenerated is either flared or vented to atmosphere.乙烯的精制 （第2 部分） 来自界区的乙烯经过乙烯级间换热器 （E-2105 ）的外壳，与来自乙烯 CO 脱除罐 （C-2107 ）中的乙烯进行级间换热。升温后的乙烯在进入乙烯预热器 （E-2106）加热到100后，进入到乙烯脱氧罐 （C-2109 ），随后进入乙烯CO 脱除罐。乙烯通过乙烯预热器将乙烯加温到最终温度后，进入到乙烯脱氧器，开车的时候也会使用乙烯预热器来进行 预热。 乙烯脱氧罐内有一个游离铜催化剂的固定床，通过将游离铜氧化成氧化铜而除去乙烯中的氧气。这种床需要用氢气稀释的氮气进行定期再生。 乙烯 CO 脱除罐内有一个氧化铜固定床。这种床层要用氧气稀释的氮气进行定期再 生。 从乙烯脱氧罐和乙烯 CO 脱除罐出来的乙烯，经乙烯级间换热器冷却到 40 后，进入乙烯干燥器 （C-2112 或 C-2113 ），乙烯干燥器中含有分子筛和活性氧化铝，这两种 物质通过物理吸附作用除去乙烯物流中的 CO2、水分和其它极性杂质。乙烯干燥器需要用热氮气定期再生。 当一台乙烯干燥器再生时，另一台备用设备启用，这样可使乙烯持续地流入到反应系统。第一部分和第二部分精制床的再生 第一部分和第二部分精制床需要定期再生。再生的周期由计时器和逻辑内部连锁控制。阀是现场手动操控的。 来自氮气总管的氮气在流量控制下进入再生氮气加热器 （E-2114）。氮气被电阻加热器加热到第 1 部分和第 2 部分中的可再生精制床再生所需的温度。热氮气通过输送管 道进入需再生床层。 所有的干燥器再生时的冷却和预负荷使用低压未精制氮气。精制床再生时产生的排放气或者送入火炬或者排入大气。 Reaction (Part 4)Resin is produced by polymerization of reactants in a fluidized bed reactor at a nominal pressure of 2,413 kPag (350 psig) and nominal temperatures of 80 to 100 deg C. An externally cooled cycle of reactant gas fluidizes the Reactor bed and removes the exothermic heat of reaction. Catalyst and purified reactants (ethylene, butene1 or hexene1, and hydrogen) are fed continuously to the Reactor. Resin flows intermittently from the Reactor through a pair of Product Discharge Systems which operate in a sequentially alternating mode.During the product discharge cycle, some of the entrained reaction gas is transferred to the other discharge system. This temporarily stored reaction gas is indirectly returned to the Reactor during the next discharge cycle, thereby minimizing the reactor gas released from the Reaction System. The resin is transported to the Product Purge Bin (C5009 in Part 5A) with the conveying gas being sent on to the Vent Recovery System (Part 5B).Certain modifiers are added to the Reactor for various reasons. An alkyl (Additive T2) is fed to the Reaction System continuously during Ziegler-Natta catalyzed polymerization. Another modifier is injected into the Reactor during upset conditions to quickly kill the polymerization reaction. This modifier, a reversible catalyst poison, can be injected through manual or automatic actuation of the Kill System control logic.Resin properties are controlled primarily by the type of catalyst used and by the cycle gas composition. The type of catalyst determines the molecular weight distribution. The quantity of comonomer in the cycle gas determines the resin density and the quantity of hydrogen determines the melt index. The Process Computing System can maintain closed-loop control of these properties by making instantaneous predictions of the resin properties in the Reactor, and adjusting variables as necessary.反应 （部分4 ） 反应物质通常在压力为 2413kPag(350psig)、温度约 80 到 100的流化床反应器内发生聚合生产出树脂。通过外部的反应气冷却循环使反应器床流化，同时除去反应热。催化剂和精制的反应物 （乙烯、丁烯-1 或己烯-1 和氢气）连续被送入反应器。树脂从反应器间歇地流入到2 条交替作业的产品卸料系统。 在产品卸料过程中，一些夹带的反应气被送到另一个卸料系统。这些在卸料系统临时储存的反应气在下一个卸料周期间接地返回反应器，这样可以减少反应系统中反应气的损失。树脂被送往产品脱气仓 （第 5A 部分中的 C-5009 ），同时输送气进入排放气回收系 统 （第5B 部分）。 出于各种原因会向反应器加入某些改性剂。当生产齐格勒那塔树脂时，向反应器内连续地注入烷基铝。在反应出现故障情况时，向反应器内注入另一种改性剂以快速地 “终止”聚合反应。这种改性剂是一种可逆的催化剂毒物，它能通过手动或终止系统逻辑控制的自动启动而注入到反应器。 树脂产品的性质主要由所采用的催化剂的类型和循环气的组成所控制。催化剂的类型决定了分子量的分布。循环气中共聚单体的量决定了树脂的密度，循环气中氢气的量决定了树脂的熔融指数。工艺计算机系统通过对反应器中的树脂性质进行瞬时的预测，同时按需要调整变量，来达到对这些性质的闭路控制。 Reaction SystemThe Reaction System consists of a Reactor (C4001), a Cycle Gas Cooler (E4002A or E4002B, an installed unconnected spare), and a Cycle Gas Compressor (K4003). The gaseous reactants (a mixture of ethylene, butene1 or hexene1, and hydrogen) and inerts are continuously cycled by the Cycle Gas Compressor through a fluidized bed of resin in which catalyst is injected. The heat of polymerization is transferred to the cycle gas and removed in the external Cycle Gas Cooler. If needed, a small amount of cycle gas is vented to the flare via the Product Purge Bin to maintain the proper reactant concentrations in the Reaction System.The Reactor is a skirtsupported cylindrical vessel with a top expanded section for disengagement of particles from the cycle gas stream. A perforated distributor plate supports the bed of granular resin a