烯烃转化单元中英文对照工艺1

第一篇：烯烃转化单元中英文对照工艺1

OCU PROCESS DESCRIPTION

烯烃转化单元工艺说明

1.1 Plant Composition 装置组成

Shanxi Coking Company Ltd.intends to build a 104 kta Olefins Conversion Unit(OCU)in the Fine Coal Chemical Zone, Zhaocheng, Hongdong County, Shanxi Province, P.R.C.The capacity of the unit will be 104 kta polymer grade propylene based on 8000 operation hours per year.The plant feed will be the Mixed C4/C5 product from the Light Olefins Recovery Unit(LORU).In addition, the plant also produces the following by-products: 山西焦化股份有限公司计划在中国山西省洪洞县赵城镇精细煤化工园区建设一套10.4万吨/年烯烃转换装置（OCU）。该装置的生产能力为10.4万吨/年聚合级丙烯，年开工率8000小时。装置进料将采用来自轻烯烃回收装置（LORU）的混合C4/C5产品。另外，该装置还生产以下副产品：

Mixed C4 to N-Butene Unit

混合C4，输送至正丁烯装置 C4+ by-product Stream

C4+副产品流

SHU Vent Gas

选择加氢装置放空气体

OCU Vent Gas

烯烃转换装置（OCU）放空气体

DME Purge

二甲醚吹扫气体

The plant shall be flexible to handle 60-120% of normal capacity and designed for 36 months between turnaround.The plant shall be designed for an operating life of 20 years.本装置的操作弹性范围为正常生产能力的60-120%，并且装置大修的间隔应为36个月。装置的使用年限应设计为20年。

The OCU unit consists of the following sections 烯烃转化装置由以下工段组成： DME Removal

二甲醚脱除单元

1st Stage Selective Hydrogenation Unit(SHU1)1段选择加氢单元（SHU1）

2nd Stage Selective Hydrogenation Unit(SHU2)2 段选择加氢单元（SHU2）Debutanizer

脱丁烷塔

OCU Feed Treatment

烯烃转换装置进料处理 OCU Reactors

烯烃转换装置反应器 Deethylenizer

脱乙烯塔 Depropylenizer

脱丙烯塔 Regeneration System

再生系统

1.2 Process Flow Description 工艺流程描述 1.2.1 DME Removal

二甲醚脱除单元

Mixed C4’s/C5’s from LORU are fed on flow control to the DME Removal Column.This column removes most of the DME and Light Ends contained in the Mixed C4/C5 Feed.来自轻烯烃回收装置的混合C4/C5在流量控制下进入二甲醚脱除塔（299-T-3101），以脱除混合C4进料中的DME和轻组分。

The DME Removal Column pressure is set to allow the column overhead to be condensed against Cooling Water and reboiled using LP2 Pressure Steam.The tower net overhead is a small vent stream containing the DME removed from the feed, as well as any light compounds in the feed.The net overhead vent stream is recycled on flow control along with the 1st Stage Selective Hydrogenation(SHU-1)vent stream to the Charge Gas Compressor Second Stage Suction Drum.DME脱除塔的压力设定为能够通过冷却水对塔顶排放气进行冷凝，并通过低低压（LP2）蒸汽对其进行重沸。塔顶净排放气流量不大，含有从进料中脱除的DME以及进料中的轻组分。在流量控制下，塔顶净排放气与第一段选择加氢装置（SHU-1）排放气循环至进料气压缩机二段入口罐。

Heat input to the tower is controlled by a flow controller on the LP2 steam-heated reboiler.Periodic analysis of the bottoms assures the bottoms product contains no more than 5 wt ppm DME.The tower bottoms pumped and cooled against Cooling Water and sent on flow control, reset by level control, to the 1st Stage Selective Hydrogenation Unit.DME脱除塔热量输入通过LP蒸汽加热重沸器的流量控制器进行控制。对塔底物料进行定期分析，确保塔底产物中DME的含量不大于5wppm。塔底物料泵出后，通过冷却水进行冷却，然后在流量控制下（基于塔底液位控制器设定值）送入SHU一段。

1.2.2 1st Stage Selective Hydrogenation(SHU-1)1段选择加氢单元（SHU1）

The bottoms of DME column are fed to the SHU Feed Surge Drum.This stream is then pumped to 1st Stage SHU Reactor pressure on flow control, reset by level control, and mixed with a portion of the 1st Stage SHU Reactor effluent recycled back to the feed.This Mixed C4/C5 Feed stream is heated to the required reactor temperature in a Low-Low Pressure steam-heated heat exchanger and then mixed with Hydrogen on flow-ratio control.二甲醚脱除塔塔底物料进入选择加氢装置进料缓冲罐，并在流量控制下（基于进料缓冲罐液位控制器设定值）泵送至第一段SHU反应器，与循环回进料的一部分第一段SHU反应器流出物混合。混合C4/C5通过低低压蒸汽加热换热器加热至要求的反应器温度，然后按照流量比与氢气混合。

Hot Mixed C4’s/C5’s and Hydrogen then pass downflow through the 1st Stage SHU Reactor where butadiene is selectively hydrogenated to n-butenes and pentadienes are selectively hydrogenated to n-butenes and n-pentenes, respectively.Since the selective hydrogenation process is exothermic, a temperature rise occurs across the reactor.The heat of

reaction is absorbed by the C4/C5 stream as it passes through the catalyst bed.The reaction product is separated in the 1st Stage SHU Reactor Separator Drum.The vapor from the drum is cooled against Cooling Water to recover C4’s/C5’s which flow to the separator drum.The remaining vent gas is recycled to the LORU.The liquid from the separator drum is pumped to reactor pressure.Some of the liquid is recycled back to the reactor on flow control and the rest is cooled and fed the 2nd Stage SHU Reactor via flow control reset by the1st Stage SHU Separator Drum level controller.The feed temperature to the 2nd Stage Reactor is controlled by by-passing some of the liquid around the 1st Stage SHU Reactor Recycle/Product Cooler.Effluent from the 1st Stage SHU contains about 2300 wt ppm butadiene and pentadienes.热混合C4/C5和氢气然后向下流经第一段SHU反应器，在该反应器中丁二烯通过选择加氢处理被转化为正丁烯，而戊二烯通过选择加氢处理被转化为正丁烯和正戊烯。由于选择加氢反应为放热反应，反应器内部会出现温升。由于反应热沿催化剂床传递，因此使用C4/C5物流对反应热进行吸收。反应产物在第一段SHU反应器分离罐中分离。来自分离罐的部分蒸气由冷却水冷却以回收C4/C5，回收的C4返回分离罐，剩余排放气循环回LORU。分离罐液体通过泵提升至反应器压力，部分液体在流量控制下循环回反应器，剩余液体经冷却后按照第一段SHU分离罐液位控制器设定值以流量控制方式进入第二段SHU反应器。第二段反应器进料温度通过第一段SHU反应器循环物料/产品冷却器的液体旁通阀来进行控制。来自第一段SHU装置的流出物约含有2300wppm的丁二烯和戊二烯。

Gradual loss of catalyst activity will occur as the active sites on the catalyst become coked.Regeneration of the catalyst is required when catalyst activity has dropped to the point when the reactor outlet temperature of about 89℃ is reached.Regeneration requires the catalyst bed to be taken offline, drained and purged of hydrocarbons, heated with

hot nitrogen and then superheated with steam.Air is metered into the stream to decoke the bed.A final nitrogen purge that contains a controlled amount of hydrogen reduces the catalyst bed.随着催化剂活性中心逐渐结焦，催化剂将逐渐失去活性。随着催化剂活性逐步降低，当反应器出口温度达到约89°C时，就需要对催化剂进行再生。催化剂再生时要求催化剂床离线，并将反应器内部烃物料排出并吹扫干净，使用热氮气进行加热，然后使用蒸汽进行过热。以流量控制方式向物流中引入空气，以对床层进行清焦。使用含一定量氢气的氮气对催化剂床进行还原。

A spare reactor is provided so that production can be maintained while one reactor is regenerated.A SHU Reactor Regeneration Electric Heater is used to heat the hot gas mixtures used to regenerate the 1st Stage SHU Reactor catalyst.设置备用反应器可以保证在对其中一台反应器进行再生期间不会中断装置运行。SHU反应器再生电加热器用于加热第一段SHU反应器催化剂再生所需的热混合气。

1.2.3 2nd Stage Selective Hydrogenation(SHU-2)2段选择加氢单元（SHU2）

The 1st Stage SHU effluent contains about 2300 wt ppm butadiene and Pentadienes combined.The total butadiene and pentadiene content is further reduced to 50 wt ppm in the 2nd Stage SHU.The 2nd Stage SHU is a once-thru system with feed heating and effluent cooling.第一段SHU流出物中含有约2300wtppm的丁二烯和戊二烯，在第二段SHU装置中，将总的丁二烯和戊二烯含量进一步降至50wtppm。第二段SHU是一个单程系统，在系统中完成进料加热和流出物冷却。

1st Stage SHU effluent after pumping and mixing with hydrogen on flow-ratio control is heated to the hydrogenation reactor temperature in a LP2 steam-heated heat exchanger and then hot mixed C4/C5’s and

hydrogen then pass upflow through the 2nd Stage SHU Reactor where the remaining butadiene is selectively hydrogenated to n-butenes and pentadienes to respective pentenes.Since the selective hydrogenation process is exothermic, a temperature rise occurs across the reactor.The heat of reaction is absorbed by the C4/C5 stream as it passes through the catalyst bed.The reaction product is immediately cooled in the 2nd Stage SHU Reactor Effluent Cooler and flows to the OCU Fresh/Recycle C4/C5 Surge Drum through a back pressure controller.The controller maintains the 2nd stage SHU Reactor in the liquid phase.将第一段SHU流出物泵出，并按照规定的流量比与氢气混合，然后通过LP2蒸汽加热换热器加热至加氢反应器温度。热混合C4/C5和氢气然后向上流经第二段SHU反应器，在该反应器中，剩余丁二烯通过选择加氢处理被转化为正丁烯，戊二稀转化为正戊烯。由于选择加氢反应为放热反应，反应器内部会出现温升。由于反应热沿催化剂床传递，因此使用C4/C5物流对反应热进行吸收。反应产物紧接着在第二段SHU反应器流出物冷却器中冷却，然后在背压控制器控制下进入OCU新鲜/循环C4/C5缓冲罐。该背压控制器用于使第二段SHU反应器中物料保持为液相。

Gradual loss of catalyst activity will occur as the active sites on the catalyst become coked.Regeneration of the catalyst is required when catalyst activity has dropped to the point when a reactor outlet temperature of about 89℃ is reached.Regeneration requires the catalyst bed to be taken offline, drained and purged of hydrocarbons, heated with hot nitrogen and then superheated with steam.Air is metered into the stream to decoke the bed.A final nitrogen purge that contains a controlled amount of hydrogen reduces the catalyst bed.随着催化剂活性中心逐渐结焦，催化剂将逐渐失去活性。随着催化剂活性逐步降低，当反应器出口温度达到约89°C时，就需要对催化剂进行再生。催化剂再生时要求催化剂床离线，并将反应器内部烃物料排出并吹

扫干净，使用热氮气进行加热，然后使用蒸汽进行过热。以流量控制方式向物流中引入空气，以对床层进行清焦。使用含一定量氢气的氮气对催化剂床进行还原。

No spare reactor is provided.When the 2nd Stage SHU Reactor requires regeneration the 1st stage SHU Reactor is temporarily run in less selective mode to reduce the butadiene and pentadiene content sufficient to feed the OCU.没有提供备用反应器。当需要对第二段SHU反应器进行再生时，应临时降低第一段SHU反应器的选择加氢性能，从而将丁二烯和戊二稀含量降至规定值，以向OCU装置进料。

A SHU Reactor Regeneration Electric Heater is used to heat the hot gas mixtures used to regenerate the 2nd Stage SHU Reactor catalyst.SHU反应器再生电加热器用于加热第二段SHU反应器催化剂再生所需的热混合气。

1.2.4 Debutanization

脱丁烷

The effluent from SHU-2 is sent to the debutanizer.This column removes C5 components to produce a Mixed C4 stream suitable for feed the OSBL N-butene Unit.来自二段选择加氢装置的流出物进入脱丁烷塔。该塔脱除C5组分以生产适合进入界区外正丁烯装置的混合C4产品流。

The debutanizer overhead is condensed by cooling water and reboiled by desuperheated LP2 pressure steam.A portion of the liquid from the debutanizer reflux drum is sent as reflux to the tower and the remaining liquid is taken as mixed C4 product, which is sent to OSBL.The bottoms C5 product is pumped and cooled to 40℃ by cooling water, before being sent to the OCT Fresh/Recycle C4/C5 Surge Drum.脱丁烷塔塔顶物经冷却水冷凝后通过减温较低压力蒸汽再煮沸。来自脱丁烷塔回流罐液体的一部分进入该塔作为回流，剩余液体抽出作为混合

C4产品输送到界区外。塔底C5产品经泵抽出后用冷却水冷却至40℃，然后输送至OCT新鲜/循环C4/C5缓冲罐。

1.2.5 OCT Reactor Feed Treatment

烯烃转换装置进料处理 The debutanizer overhead is combined with the Mixed C4 Raffinate from the N-Butene unit(OSBL)and the recycle C4/C5’s in the OCT Fresh/Recycle C4/C5 Surge Drum.The Mixed C4s/C5’s from this drum are pumped to the OCT reaction pressure and combined with Fresh and Recycle Ethylene, mixed in a static mixer to dissolve the Ethylene in the liquid C4/C5, then treated in the OCT Reactor Feed Treater.The operating pressure of the treater is such that the Mixed C4+C5/Ethylene feed is in liquid phase.脱丁烷塔塔顶物料与界区外正丁烯装置混合C4的抽余液及循环C4/C5在OCT新鲜/循环C4/C5缓冲罐中混合。来自该罐的混合C4/C5经泵提升至OCT反应器压力，并与新鲜和循环乙烯在静态混合器中混合，以使乙烯溶解在液体C4/C5中，然后在OCT反应器进料处理器中进行处理。处理器设计运行压力能够保证使混合C4+C5乙烯进料保持为液相。

The OCT Reactor Feed Treater is designed to remove trace potential catalyst temporary poisons in the Mixed C4+C5/Ethylene stream that could impair the OCT Reactor performance such as oxygenates, sulfur, alcohols, carbonyls, and/or water.There are two treaters provided in the system.One is normally in operation;while the other is in regeneration or on standby.The treater regeneration initially requires draining of the liquid inventory followed by regeneration using hot Nitrogen from the Regeneration Gas System plus a supplemental electric heater.The treater effluent passes through a filter to remove any adsorbent dust.OCT反应器进料处理器用于脱除C4+C5乙烯混合进料中的痕量催化剂毒物，如氧合物、羰基化合物、乙醇、硫化合物和/或水，以防止对OCT反应器运行性能造成影响。系统设置两台处理器：一台通常处于运行状态，另一台用于再生目的或作为备用处理器。在对处理器进行再生时，首先对处理器进行排液，然后采用来自再生气系统的热氮气和辅助电加热器进行再生。处理器流出物送入过滤器，以脱除任何吸附剂粉末。

1.2.6 OCU Reactors

烯烃转换装置反应器

In this section, the OCU Reactor feed is heated to the required reaction temperature, passed through the OCU Reactor and cooled prior to OCU reactor effluent fractionation.The main reactions that occur are ethylene plus 2-butene forming propylene and ethylene plus 2-pentene forming propylene plus 1-butene.Some byproducts, primarily C5 to C8 olefins, are also formed by side reactions.在本工段，将OCU反应器进料加热至要求的反应温度后送入OCU反应器，并且在将OCU反应器流出物送入精馏塔之前应先进行冷却。主要OCU反应是以乙烯和2-丁烯作为原料经反应生成丙烯以及乙烯和2-戊烯反应生成丙烯和1-丁烯。另外，也发生一些副反应，所生成的副产品主要为C5-C8烯烃。

The OCU reactor feed is vaporized and heated to the required OCU Reactor temperature in an OCT Reactor Feed/Effluent Exchanger followed by the OCT Reactor Feed Heater.The OCU reaction occurs in a fixed bed catalytic reactor.The OCU catalyst is a mixed catalyst bed comprised of magnesium oxide and tungsten oxide on silica.The reactions occurring are essentially isothermal.OCU反应器进料先由OCT反应器进料/流出物换热器进行汽化，然后再通过OCT反应器进料加热器加热至要求的OCU反应器温度。OCU反应在固定床催化反应器中进行。OCU催化剂为混合催化剂，由氧化镁和以硅藻土为载体的氧化钨制备而成。所有反应基本上均为等温反应。

Prior to entering the recovery section, the OCU Reactor effluent is cooled by interchange with reactor feed followed by the OCT Reactor Effluent Cooler against Cooling Water.在进入回收工段之前，OCU反应器流出物首先与OCU反应器进料进行换热，然后在OCT反应器流出物冷却器中通过冷却水进行冷却。

Regeneration of the OCU Reactor requires the catalyst bed to be taken offline, purged of hydrocarbons, and heated with hot Nitrogen.A nitrogen-air mixture is then fed to the reactor to decoke the bed.A nitrogen purge, which contains a controlled amount of hydrogen, reduces the catalyst bed.A high temperature Nitrogen desorption step follows to remove any traces of oxygen and water from the bed.Hot regeneration gases for the regeneration of the OCU Reactor are provided by the Regeneration Gas Heater.在对OCU反应器进行再生时需要使催化剂床离线、将烃物料吹扫干净、使用热氮气进行加热。然后，向OCU反应器注入氮气-空气混合气体以对床层进行清焦。使用含一定量氢气的氮气对催化剂床进行还原。随后进行热氮气解吸，以将催化剂床的痕量氧气和水分脱除。OCU反应器再生用高温再生气由再生气加热器提供。

1.2.7 Deethylenizer 脱乙烯塔

The OCU Reactor effluent is chilled by vaporizing a portion of the Recycle Ethylene in the Deethylenizer Feed Chiller.The chilled feed then flows to the Deethylenizer column.OCU反应器流出物通过在脱乙烯塔进料深冷器中对一部分循环乙烯进行汽化来实现冷却。然后，已冷却进料流入脱乙烯塔。

The Deethylenizer pressure is selected to recycle vent gas from the reflux drum and to allow the overhead to condense against-24℃ Propylene Refrigerant from the Propylene Refrigeration System of the LORU.A small vent gas stream containing Hydrogen, Methane, and Ethylene flows from the reflux drum on flow control to the LORU for recovery.10

脱乙烯塔设计压力能够对来自回流罐的排放气进行循环，并使用来自LORU装置丙烯制冷系统的-24°C丙烯冷剂对塔顶物料进行冷凝。一小股含有氢气、甲烷和乙烯的排放气以流量控制方式从回流罐流入LORU进行回收。

Fresh Ethylene liquid is fed to the Deethylenizer Reflux Drum.The bulk of the tower overhead is condensed against Propylene Refrigerant and sent to the Deethylenizer Reflux Drum.Liquid from the reflux drum is split, with a portion pumped to OCU Reactor Feed Treater pressure to supply Recycle Ethylene, and a portion pumped separately to supply tower reflux on flow control.The net Fresh plus Recycle Ethylene is pumped and sent to the Deethylenizer Feed Chiller on flow control.A portion of the Recycle Ethylene stream is vaporized in this heat exchanger.The rest bypasses the feed chiller on temperature control, in order to maintain the OCU Reactor feed in the liquid phase at the outlet of the OCU Reactor Feed Treater.The Recycle Ethylene stream then mixes with Fresh and Recycle C4’s/C5’s at the OCU Reactor Feed Treater Mixer and flows to the OCU Reactor Feed Treaters.新鲜乙烯液体送入脱乙烯塔回流罐。大量脱乙烯塔塔顶物料经丙烯冷剂冷凝后送入脱乙烯塔回流罐。脱乙烯塔回流罐中的液体分为两股：一股液体泵送至OCU反应器进料处理器作为循环乙烯，另外一股液体以流量控制方式泵送回脱乙烯塔作为回流。净新鲜乙烯和循环乙烯以流量控制方式泵送至脱乙烯塔进料深冷器。在脱乙烯塔进料深冷器中，一部分循环乙烯被汽化，而剩余循环乙烯以温度控制方式进入脱乙烯塔进料深冷器旁路，以确保将来自OCU反应器进料处理器出口的OCU反应器进料保持为液相。然后，循环乙烯通过OCU反应器进料处理器混合器与新鲜和循环C4、C5混合后流入OCU反应器进料处理器。

The tower is reboiled by LP2 Steam with the bottoms product flowing to the Depropylenizer on flow control, reset by level control.A temperature

controller is used to control the reboiler steam to maintain the proper bottoms specification.脱乙烯塔内物料通过LP2蒸汽进行重沸，塔底产品按照液位控制器设定值以流量控制方式流入脱丙烯塔。通过温度控制器对重沸器蒸汽流量进行控制，以确保塔底产品始终符合规格要求。

1.2.8 Depropylenizer

脱丙烯塔

The Depropylenizer separates the Deethylenizer bottoms into three products: 脱丙烯塔（299-T-3302）将脱乙烯塔塔底物料分离为三种产品： • Polymer Grade Propylene(overhead)聚合物级丙烯（塔顶产品）； • C4/C5 Recycle(side-draw)C4、C5循环物流（侧线抽出）； • C4+ byproduct(bottoms product)C4+副产品（塔底产品）The tower pressure is selected to condense the overhead against Cooling Water and reboil against LP2 Steam.The tower C4/C5 side-draw is cooled in a Cooling Water heat exchanger and recycled on flow control to mix with the Fresh C4/C5 feed in the OCT Fresh/Recycle C4/C5 Surge Drum.脱丙烯塔设计压力能够通过采用冷却水对塔顶产品进行冷凝，然后使用LP2蒸汽进行重沸。脱丙烯塔C4、C5侧线抽出物流通过冷却水换热器进行冷却，然后以流量控制方式循环回OCT新鲜/循环C4、C5缓冲罐，并与新鲜C4、C5进料混合。

The tower overhead is completely condensed and sent to the Depropylenizer Reflux Drum.The liquid from this drum is then pumped and split with a portion providing reflux, on flow control for the tower.The remainder of the liquid is the Polymer Grade Propylene Product and is sent to OSBL on flow control reset by level control.脱丙烯塔塔顶产品经完全冷凝后，送入脱丙烯塔回流罐。然后，将脱丙烯塔回流罐中的液体泵出并分为两股物流：一股液体以流量控制方式送

回脱丙烯塔作为回流，剩余液体作为聚合物级丙烯产品按照液位控制器设定值以流量控制方式送至界区外（OSBL）。

The tower bottoms product is C4+ by-product.It is cooled against cooling water and sent on flow control reset by level control to OSBL.脱丙烯塔塔底产品为C4副产品。该副产品按照液位控制器设定值以流量控制方式送至OSBL。

A temperature controller is used to control the reboiler steam rate to the Depropylenizer.通过温度控制器对自重沸器去脱丙烯塔的蒸汽流量进行控制。1.2.9 Regeneration System 再生系统

A treater Regeneration System is used to provide hot Regeneration Gas during the heating stage of regeneration and cold Regeneration Gas during the cooling stage of regeneration.处理器再生系统用于为每一再生加热阶段提供高温再生气以及为再生冷却阶段提供低温再生气。

1.2.9.1 Treater Regeneration 处理器再生

Hot nitrogen is supplied from the Regeneration Gas System to regenerate the OCU Reactor Feed Treaters.The Regeneration Nitrogen is supplied at the battery limits.Cold Regeneration Nitrogen is sent as cold Regeneration Nitrogen to treater when required.Hot Regeneration Nitrogen is first heated against HP steam in the Treater Regeneration Gas Steam Heater and further heated in the Treater Regeneration(electric)Gas Heater before flowing to the treater when required.由再生气系统提供热氮气，OCU反应器进料处理器进行再生。自界区提供再生氮气。低温再生氮气当需要时提供给OCU反应器进料处理器用作低温再生氮气。当要求向处理器引入高温再生氮气之前，应先通过处理器再生气体（电）加热器对高温再生氮气进行进一步加热。

The relative amounts of hot and cold Regeneration Nitrogen flow and temperature are controlled automatically to achieve complete regenerations within the required cycle times.Although the treaters are typically designed for a 48 hour adsorption cycle, they are typically designed for a 24 to 36 hour regeneration cycle.高温和低温再生氮气相对流量和温度采用自动控制方式，以确保在规定的再生周期内实现完全催化剂再生。尽管处理器吸附周期通常设计为48小时，但其再生周期通常设计为24到36小时。

Spent Regeneration Nitrogen returning from the treaters is cooled and sent to the Flare System.来自处理器的废再生氮气经冷却后送入火炬系统。1.2.9.2 C4/C5 Stripping System

C4/C5汽提系统

This system is a closed–loop process where the pressure is dependent on condensing C4’s/C5’s against Cooling Water.The system includes a C4/C5 Stripping Holding Drum, which is inventoried from the cooled 2nd Stage SHU Reactor effluent stream.Filling is controlled so that the rate is less than 5% of the forward flow from the 2nd Stage SHU Reactor effluent to avoid disturbing the OCU operation.In the first stage of regeneration, the butenes are pumped to sufficient pressure, vaporized in a LP2 Steam heater and superheated to about 120℃.The hot C4/C5 vapor is then sent to the OCU Reactor Feed Treaters on flow control where it strips the C4’s/C5’s trapped on the adsorbent pores(stripping/warm soak).The effluent vapor is then condensed in the C4/C5 Stripping Condenser against Cooling Water and collected in the C4/C5 Stripping Holding Drum.Pressure control on the C4/C5 Stripping Holding Drum allows for venting of non-condensables during this stripping/warm soak step.14

丁烯汽提系统为密闭回路系统，运行压力取决于通过冷却水对C4/C5 进行的冷凝。丁烯汽提系统包括一个C4/C5 汽提储罐，用于存储来自第二段SHU反应器的已冷却流出物。对去C4/C5 汽提储罐的进料流量进行控制，确保低于来自第二段SHU反应器流出物流量的5%，以避免影响OCU装置的正常运行。在第一阶段再生期间，通过泵将丁烯压力提升至足够高后经由LP2蒸汽加热器进行汽化，再过热至120℃。然后，以流量控制方式将C4/C5气体送入OCU反应器进料处理器，以将截留在吸附剂空隙中的C4/C5 汽提出来（汽提/温热浸泡）。汽提后的丁烯气体通过C4/C5 汽提冷凝器使用冷却水冷凝后收集至C4/C5 汽提储罐。对C4/C5 汽提储罐进行压力控制有助于在汽提/温热浸泡期间将不冷凝气排放出来。

When the stripping step is complete, the spent butenes/C5’s in the C4/C5 Stripping Holding Drum are drained by pumping on flow control to the drain drum of the regenerating treater.当完成汽提操作后，通过泵以流量控制方式将C4/C5汽提储罐中的废丁烯排入再生处理器排液罐。

第二篇：中英文对照A

《美国口语惯用法例句集粹》Ａ

A(Page 1-4)

1.about

1)

2)

3)

4)

5)

6)

7)I'd like to know what this is all about.我想知道这到底是怎么回事。How about a fish sandwich? 来一块鱼肉三明治怎么样？What about me? 我怎么样？I'm not about to go in that old house.我是不会进那幢旧房子的！Yes I remember that night.What about it? 是的，我记得那个晚上，那又怎样？What's this all about? 这到底是怎么回事？It's about time you showed up!差不多是你该露面的时候了。

2.above

1)

2)Above all, I want everything quiet.首要的是：我要一切保持安定。Tom thinks he's above hard work.汤姆认为自己没必要努力工作。

3.act

1)

2)

3)

4)

5)

6)Would you please act out what happened? 你能把发生的事演示一下吗？Watch Ricky.He sometimes likes to act up in class.注意里基，他又是喜欢在课堂上捣蛋。That profane comedian needs to clean up his act.那个爱说粗言秽语的喜剧演员应该净化一下自己的言行。We need to get our act together and come to see you.我们需要统一意见后来见你。The newspapers called the earthquake an act of God.报纸上称那次地震为天灾。Masa is a class act.玛莎是位杰出的女性。

4.action

1)

2)

3)

4)We're going to bring action against our debtors.我们打算控告我们的债务人。Did you see any action in yesterday's ballgame? 昨晚的棒球比赛中你看到有什么有趣的精彩场面吗？Our community is going to take action against the proposed waste dump.我地区要采取行动反对那项垃圾处理场的提案。Jim wants to go where the action is.吉姆想去有刺激性的地方。

5.advantage

1)

2)Our opponents have a height advantage on us.我们的对手在身高上比我们占有优势。Nobody likes to be taken advantage of.没有人喜欢被捉弄（或：被欺骗、利用）

6.after

1)

2)

3)

4)I think that girl is after you.我想那女孩是在追你。It looks like things are gonna work out after all.看起来事情终会解决的。This soft drink has a nasty aftertaste.这软饮料有种让人难受的余味。I see your point, but don't you think it's way after the fact.我明白你的意思，但你不觉

得这已是“事后诸葛亮”了吗？

7.again

1)I could go to Japan again and again.我可以一而再、再而三地去日本。（注：意指不会感到

厌倦）

8.age

1)

2)Would you please act your age!请你做事要有一个与自己年龄相称的样子。This is a “coming of age” movie.这是一部成人影片。

9.air

1)

2)

3)

4)

5)

6)

7)

8)

9)I need to go outside and get some air.我需要出去呼吸点新鲜空气。I don't know what's wrong, but can feel it in the air.虽然我不知道到底是出了什么差错，但我能隐隐约约感觉到。Mike was sad when they took his favorite program off the air.当迈克喜欢的节目被取消时，他感到很伤心。The sale of our house is still up in the air.我们的房子出勤率售一事还没有最后定下来。After winning the championship, I felt I could walk on air.获得冠军后，我飘飘欲仙。Your sister is such an airhead.你姐姐真是来个没有头脑的人。Janet Jackson's new song is getting lots of airplay.珍妮〃杰克逊的新歌到处都在不断地播放。That last time I took a plane, I got airsick.上次我乘飞机时晕机了。I hope there's no bad air between us.我希望我们之间的关系不要很别扭。

10.all

1)

2)

3)

4)

5)

6)

7)

8)

9)

10)

11)

12)

13)It's looks like we won't be going after all.看起来最后我们还是不能去。We've all but finished the project.我们已几乎完成了那个项目。All in all I'd say it's been a very productive day.总的来说，我认为这一天过得很充实。Let's go all-out and win this game!让我们尽全力来打赢这场比赛。We knew it was all over when we saw the building burst.当我们看见那座建筑突然起火时，我们知道一切全完了。We wish you all the best.我们大家祝福你一切如意。If it's all the same to you, I'd just as soon not go.如果这对你都是一回事的话，我就不想去了。They were running from the police like all get-out.他们以极快的速度逃脱警察的追赶。I didn't see them come in at all.我根本高没有发现他们的进来。Let's settle this matter once and for all.让我们来把这个问题一次性地彻底解决掉。Mark is an all-around athlete.马克是一个全能运动员。Did you get to play in the all-star game? 你入选全明星队的比赛了吗？He bloke the all-time record in the 100-meter run at his school.他打破了他所在的学校

100米跑的历史最高记录。

11.alley

1)Working on cars isn't up my alley.修理汽车不是我拿手的活儿。

12.alone

1)

2)I just wanna be left alone.我只是想一个人呆会儿。Can't you just leave well enough alone? 你不能少管一些闲事吗？

13.along

1)

2)You knew all along what was going on.你从一开始就知道所发生的事。Debbie doesn't get along with Steve.戴比和史蒂夫相处得不好。

1)

2)

3)

4)

5)Mr.Pak came here searching for the American dream.帕克先生来到这儿寻求他的“美国梦”。Some foreigners become Americanized while living in the U.S.一些外国人在美国居住时被美国化了。Not having any job freedom would be totally unAmerican.没有选择职业的自由是完全违背美国精神传统的。Bill is an all-American quarterback.比尔是全美（橄榄球）明星赛的四分卫队员。I just can't go on the American way.我无法适应美国方式。

15.animal

1)

2)Water-skiing really brings out the animal in Tom.滑水运动真正激发出了汤姆的活力与激情。The young actor emits a lot of animal magnetism on the screen.那个年轻演员在荧幕

上充分显示出他的性魅力。

16.answer

1)I called Emi but there was no answer.我给埃米打了电话，但是没人接。

17.apple

1)

2)

3)

4)

5)Have you ever been to the Big Apple? 你去过纽约吗？Do I sense an apple of discord between you two? 你问我有没有感觉出你们两人之间的不和，是吗？Heather is the apple of my eye.希瑟是我的掌上明珠。Rita likes to keep everything in apple-pie order.丽塔喜欢把一切都弄得井井有条。Dennis has always been an apple polisher.丹尼斯一直就是一个马屁精。

18.arm

1)

2)

3)

4)You don't have to twist my arm to get me to go with you.用不着你强迫我跟你走。My father is a hopeless armchair quarterback.我爸爸是一个没救了的纸上谈兵的人。The suspects are armed and dangerous.嫌疑犯带有武器，十分危险。Every spring the park is filled with lovers walking arm in arm.每到春天公园里到处都是

手挽手散步的恋人。

19.around

1)

2)Coach Johnson has been around for 30 years.约翰逊教练已有三十年的经验了。Someone is on duty here around-the-clock.有人在这里昼夜值班。

20.as

1)

2)

3)

4)

5)

6)It looks as if someone has already been here.看起来在人来过这里了。As for me, I'm going home.至于我，我准备回家。Marty is acting as if nothing happened.马蒂表现得像什么也没发生过一样。I want this room left as is.我希望这间房子保持原样。The changes will begin taking place as of tomorrow.变动从明天开始实施。Police are baffled as to the whereabouts of the kidnappers.警察局搜寻绑架者的工作受

挫。

1)

2)

3)

4)Our gas bill average about $50 a month.我们每个月的煤气费平均50美元。On the average, I'd say we eat chicken once a week.我们平均每周吃一次鸡肉。Kent describes himself as just an average Joe.肯特视自己为一名普通的美国人。On the average day, over 100,000 kids bring guns to school in the U.S.在美国平常日

子里，有100,000个孩子带手枪去上学。

22.away

1)

2)

3)

4)

5)What makes you think you're gonna get away with this? 是什么使你认为你可以免受处罚？I wish they'd do away with these complicated tax forms.我希望他们能费除掉这些复杂的税务表格。We're planning a weekend getaway for our anniversary.我们正在为庆祝我们的纪念日而安排一次周末的外出活动。Tom wants to run away from home.汤姆想从家里出逃。Dave and Kathy are going to steal away on vacation.戴夫和凯茜计划在假期里偷偷跑出

去。

第三篇：中英文对照

AEROFLEX “亚罗弗”保温 ALCO “艾科”自控 Alerton 雅利顿空调 Alfa laval阿法拉伐换热器 ARMSTRONG “阿姆斯壮”保温 AUX 奥克斯

BELIMO 瑞士“搏力谋”阀门 BERONOR西班牙“北诺尔”电加热器 BILTUR 意大利“百得”燃烧器 BOSIC “柏诚”自控 BROAD 远大

Burnham美国“博恩汉”锅炉 CALPEDA意大利“科沛达”水泵 CARLY 法国“嘉利”制冷配件 Carrier 开利 Chigo 志高

Cipriani 意大利斯普莱力

CLIMAVENETA意大利“克莱门特” Copeland“谷轮”压缩机 CYRUS意大利”赛诺思”自控 DAIKIN 大金空调

丹佛斯自控 Dorin “多菱”压缩机

DUNHAM-BUSH 顿汉布什空调制冷 DuPont美国“杜邦”制冷剂 Dwyer 美国德威尔 EBM “依必安”风机

ELIWELL意大利“伊力威”自控 Enfinilan 英国“英菲尼兰“阀门 EVAPCO美国“益美高”冷却设备 EVERY CONTROL意大利“美控” Erie 怡日

FRASCOLD 意大利“富士豪”压缩机 FRICO瑞典“弗瑞克”空气幕 FUJI “富士”变频器

FULTON 美国“富尔顿”锅炉 GENUIN “正野”风机 GREE 格力

GREENCOOL格林柯尔 GRUNDFOS “格兰富”水泵 Haier 海尔 Hisense 海信 HITACHI 日立

霍尼韦尔自控 Johnson 江森自控 Kelon 科龙

KRUGER瑞士“科禄格”风机 KU BA德国“库宝”冷风机 Liang Chi 良机冷却塔 LIEBERT 力博特空调 MARLEY “马利”冷却塔 Maneurop法国“美优乐”压缩机 McQuary 麦克维尔 Midea 美的 MITSUBISHI三菱

Munters 瑞典“蒙特”除湿机 Panasonic 松下 RANCO “宏高”自控

REFCOMP意大利“莱富康”压缩机 RIDGID 美国“里奇”工具 RUUD美国“路德”空调 RYODEN “菱电”冷却塔 SanKen “三垦”变频器 Samsung 三星 SANYO 三洋

ASWELL英国森威尔自控 Schneider 施耐德电气 SenseAir 瑞典“森尔”传感器 SIEMENS 西门子

SINKO ",28商机网;新晃“空调 SINRO “新菱”冷却塔 STAND “思探得”加湿器 SWEP 舒瑞普换热器 TECKA “台佳”空调 Tecumseh“泰康”压缩机 TRANE 特灵

TROX德国“妥思”风阀 VASALA芬兰“维萨拉”传感器 WILO德国“威乐”水泵 WITTLER 德国”威特”阀门 YORK 约克

ZENNER德国“真兰”计量

第四篇：中英文对照

医院中英文对照

发热门诊Have Fever主治医师Doctor-in-charge 供应室Supply Room谢绝入内No entering 红灯亮时谢绝入内No entering when red light

彩超、心电图Colorful Cardiogram/ECG住院楼Inpatient Building 透析血磁EndoscopeDept.护士Nueser康复理疗科RehabilitationPhysiotherapyDept.中药计价China medical price account肛肠科Ano-proctology

皮肤、肛肠、男性科、泌尿科候诊Dermatology、Ano-proctology、male Urology Clinic 皮肤科、肛肠科、男性科、泌尿科Dermatology、Ano-proctology、male Urology Dept 中医科Traditional Chinese Medicine五官科ENT Dept.男性科、泌尿科 Male urology Dept.安全出口Exit

预防保健科Medical center for health preventionand care

后勤科、药库Logistic Room、Seore入院登记In-patient Admisson 高压氧治疗Hyperbaric Oxygehation Therapy碎石中心ESWL Center 急救中心Emergency Center挂号收费Registration

中心药房Cenreral Pharmacy内科门诊Internal Medicine Clinic会议室Meeting Room手外科Hand Surgery 产科Obstentrics Dept.骨外科Orthopedics Dept.神经、烧伤外科Neurosurgery.Plaseric surgey Dept.麻醉科Anaesthesiology手术室Operation Room 泌尿、肿瘤外科Urologic.Gumorsurgery Dept.妇科Gynecology Dept.内二科Internal Medicine.Ward 2产房及爱婴中心Delivery Room内一科Internal Medicine.Ward 1洗手间Toilet

普外、胸外科Surgey、Thoracic Surgey Dept.皮肤科Dermatology Dept.中医骨伤科Traditional Mediaine or Thopaedics餐厅Dining Room 配餐室Pantry Room后勤科Logistics Dept.电工室Electrician Room接待室Dermatology Room 内、儿科候诊 Internal medicine.Pediatrics功能检查候诊Function Exam 中医科候诊TCM Clinic放射科候诊Radiology Clinic 妇科门诊Gynecology Dept.产科候诊Obstentrics Clinic 肛肠科候诊Ano-proctology妇科候诊Gynecology Clinic 产科门诊Obstentrics Dept.五官科候诊ENT.Clinic 外科候诊Surgery Clinic输液中心Transfusion Center 皮肤、泌尿科候诊 Dermatology.Male Urology Clinic检验候诊Clinical Laborotories 家属休息Relation Rest Room口腔科门诊Stomatology Clinic 内儿科Internal Medicine.Pediaarics镜检科Endoscope Dept.外科Surgrey Dept.检验中心Laboratory Center 功能检查Function Exam Dept.登记处Registration 预防保健门诊Hygine ＆ Public Health Dept.收费处Cashier 美容科、镜检科门诊 Cosmetology Dept.Endoscope Clinic

收费健康发证Gharge lssue Bill of Health试敏观察室Scratch Espial Room

第五篇：中英文对照

共轨技术

随着人们对低油耗、低废气排放、发动机低噪声的需求越来越大，对发动机和燃油喷射系统的要求也越来也高。对柴油发动机燃油喷射系统提出的要求也在不断增加。更高的压力、更快的开关时间，以及根据发动机工况修订的可变的流量速率曲线，已经使得柴油发动机具有良好的经济性、低污染、高动力性，因此柴油发动机甚至进入了豪华高性能轿车领域。达到这些需求的前提是拥有一个可以精确雾化燃油并具有高喷油压力的燃油喷射系统。同时，喷油量必须精确计算，燃油流量速率曲线必须有精确的计算模型，预喷射和二次喷射必须能够完成。一个可以达到以上需求的系统即共轨燃油喷射系统。

共轨系统包括以下几个主要的部分： ①低压部分，包含燃油共轨系统组件。

②高压系统，包含高压泵、油轨、喷油器和高压油管等组件。

电控柴油机系统EDC主要由系统模块，如传感器、电子控制单元和执行机构组成。共轨系统的主要部分即喷油器。它们拥有一个可以快速开关喷嘴的执行阀(电磁阀或压电触发器)，这就允许对每个气缸的喷射进行控制。

所有的喷油器都由一个共同的油轨提供燃油，这就是“共轨”的由来。在共轨燃油喷射系统中，燃油喷射和压力的产生是分开的。喷油压力的产生与发动机转速和喷油量无关。EDC控制每个组件。

(1)压力产生。

燃油喷射和压力的产生是通过蓄能器分离开来。将具有压力的燃油提供给为喷射做好准备的共轨系统的蓄能器。

由发动机驱动的连续运转的高压泵提供所需喷油的压力。无论发动机的转速高低，还是燃油喷射量的多少，油轨中的压力均维持在一定值。由于几乎一致的喷油方式，高压泵的设计可以小的多，而且它的驱动转矩可以比传统燃油喷射系统低，这源于高压泵的负载很小。

高压泵是径向活塞泵，在商用车上有时会使用内嵌式喷油泵。(2)压力控制

所应用的压力控制方法主要取决于系统。

一种控制油轨压力的方式是通过一个压力控制阀对高压侧进行控制。不需喷射的燃油通过压力控制阀流回到低压回路。这种控制回路允许油轨压力对不同工况(如负载变化时)迅速做出反应。

在第一批共轨系统中采用了对高压侧的控制。压力控制阀安装在燃油轨道上更可取，但是在一些应用中，它被直接安装在高压泵中。

另一种控制轨道压力的方式是进口端控制燃油供给。安装在高压泵的法兰上的计量单元保证了泵提供给油轨精确的燃油量，以维持系统所需要的喷油压力。

发生故障时，压力安全阀防止油轨压力超过最大值。

在进口端对燃油供给的控制减少了高压燃油的用量，降低了泵的输入功率。这对燃油消耗起到积极的作用。同时，流回油箱的燃油温度与传统高压侧控制的方法相比得到了降低。

双执行器系统也是一种控制轨道压力的方式，它通过计算单元对压力进行控制，并且通过压力控制阀对高压端进行控制，因此同时具备高压侧控制与进口端燃料供给控制的优势。

(3)燃油喷射

喷油器直接将燃料喷到发动机的燃烧室。它们由与燃油轨道直接相连的短高压油轨提供燃油。发动机的控制单元通过与喷油器结合在一起的控制阀的开闭控制喷油嘴的开关。

喷油器的开启时间和系统油压决定了燃油供给量。在恒压状态下，燃油供给量与电磁阀的开启时间成正比，因此与发动机或油泵的转速(以时间为计量的燃油喷射)无关。

(4)液压辅助动力

与传统燃油喷射系统相比，将压力的产生与燃油的喷射分离开来，有利于燃烧室的充分燃烧。燃油喷射压力在系统中基本可以自主选择。目前最高燃油压力为1600巴，将来会达到1800巴。

共轨系统通过引入预喷射或多次喷射可以进一步减少废气排放，也能明显降低燃烧噪声。通过多次触发高速转换阀的开闭可以在每个喷射周期内实现多达5次的喷射。喷油针阀的开闭动作是液压辅助元件助力的，以保证喷射结束的快速性。

(5)控制和调节

发动机的控制单元通过传感器检测加速踏板的位置以及发动机和车辆的当前工况。采集到的数据包括：

① 曲轴转速和转角； ② 燃油轨道的压力； ③ 进气压力；

④ 进气温度、冷却液温度和燃油温度； ⑤ 进气量； ⑥ 车速等。

电控单元处理输入信号。与燃烧同步，电控单元计算施加给压力控制阀或计算模块、喷油器和其他执行机构(如EGR阀，废气涡轮增压器)的触发信号。

喷油器的开关时间应很短，采用优化的高压开关阀和专业的控制系统即可实现。

根据曲轴和凸轮轴传感器的数据，对照发动机状态(时间控制)，角度/时间系统调节喷油正时。电控柴油机系统(EDC)可以实现对燃油喷射量的精确计算。此外，EDC还拥有额外的功能以进一步提高发动机的响应特性和便利性。

其基本功能包括对柴油燃油喷射正时的精确控制，和在给定压力下对油量的控制。这样，它们就保证了柴油发动机具有能耗低、运行平稳的特点。

其他开环和闭环控制功能用于减少废气排放和燃油消耗，或提供附加的可靠性和便利性，具体例子有：

① 废气在循环控制； ② 增压控制； ③ 巡航控制；

④ 电子防盗控制系统等。(6)控制单元结构。

由于发动机控制单元通常最多有8个喷油器输出口，所以超过八缸的发动机需要两个控制单元。它们通过内置高速CAN网络的“主/从”接口进行连接，因此也拥有较高的微控制器处理能力。一些功能被 分配给某个特定的控制单元(如燃料平衡控制)，其功能根据需求情况(如检测传感器信号)可以动态地分配给一个或多个控制单元。

The Common Rail Calls for lower fuel consumption, reduced exhaust-gas emission, and quiet engines are making greater demands on the engine and fuel-injection system.The demands placed on diesel-engine fuel-injection systems are continuously increasing.Higher pressures, faster switching times, and a variable rate-of-discharge curve modified to the engine operating state have made the diesel engine economical, clean, and powerful.As a result, diesel engines have even entered the realm of luxury-performance sedans.These demands can only be met by a fuel-injection pressure.At the same time the injected fuel quantity must be very precisely metered, and the rate-of-discharge curve must have an exact shape, and pre-injection and secondary injection must be performable.A system that meets these demands is the common-rail fuel-injection system.The main advantage of the common-rail system is its ability to vary injection pressure and timing over a broad scale.This was achieved by separating pressure generation(in the high-pressure pump)from the fuel-injection system(injection).The rail here acts as a pressure accumulator.Principle of the Common Rail The common-rail system consists of the following main component groups: ① The low-pressure stage, comprising the fuel-supply system components;② The high-pressure system, comprising components such as the high-pressure pump, fuel-rail, injector, and high-pressure fuel lines.The electronic diesel control(EDC), consisting of system modules, such as sensors, the electronic control unit, and actuators.The key components of the common-rail system are the injectors.They are fitted with a rapid-action valve(solenoid valve or piezo-triggered actuator)which opens and closes the nozzle.This permits control of the injection process for each cylinder.All the injectors are fed by a common fuel rail, this being the origin of the term “common rail”.In the common-rail fuel-injection system, the function of pressure generation and fuel injection are separate.The injection pressure is generated independent of the engine speed and the injected fuel quantity.The electronic diesel control(EDC)controls each of the components.(1)Pressure Generation.Pressure generation and fuel injection are separated by means of an accumulator volume.Fuel under pressure is supplied to the accumulator volume of the common

rail ready for injection.A continuously operating high-pressure pump driven by the engine produces the desired injection pressure.Pressure in the fuel rail is maintained irrespective of engine speed or injected fuel quantity.Owing to the almost uniform injection pattern, the high-pressure pump design can be much smaller and its drive-system torque can be lower than conventional fuel-injection systems.This results in a much lower load on the pump drive.The high-pressure pump is a radial-piston pump.On commercial vehicles, an in-line fuel-injection pump is sometimes fitted.(2)Pressure Control The pressure control method applied is largely dependent on the system.One way of controlling rail pressure is to control the high-pressure side by a pressure-control valve.Fuel not required for injection flows back to the low-pressure circuit via the pressure-control valve.This type of control loop allows rail pressure to react rapidly to changes in operating point(e.g.in the event of load changes).Control on the high-pressure side was adopted on the first common-rail systems.The pressure-control valve is mounted preferably on the fuel rail.In some applications, however, it is mounted directly on the high-pressure pump.Another way of controlling rail pressure is to control fuel delivery on the suction side.The metering unit flanged on the high-pressure pump makes sure that the pump delivers exactly the right quantity of fuel rail in order to maintain the injection pressure required by the system.In a fault situation, the pressure-relief valve prevents rail pressure from exceeding a maximum.Fuel-delivery control on the suction side reduces the quantity of fuel under high pressure and lowers the power input of the pump.This has a positive impact on fuel consumption.At the same time, the temperature of the fuel flowing back to the fuel tank is reduced in contrast to the control method on the high-pressure side.The two-actuator system is also a way of controlling rail pressure, which combines pressure control on the suction side via the metering unit and control on the high-pressure side via the pressure-control valve, thus marrying the advantages of high-pressure-side control and suction-side fuel-delivery control.(3)Fuel Injection.The injectors spray fuel directly into the engine’s combustion chambers.They are supplied by short high-pressure fuel lines connected to the fuel rail.The engine control unit controls the switching valve integrated in the injector to open and close

the injector nozzle.The injector opening times and system pressure determine the quantity of fuel delivered.At a constant pressure, the fuel quantity delivered is proportional to the switching time of the solenoid valve.This is, therefore, independent of engine or pump speed(time-based fuel injection).(4)Potential Hydraulic Power.Separating the functions of pressure generation and fuel injection opens up future degrees of freedom in the combustion process compared with conventional fuel-injection systems;the injection pressure at pressure at present is 160 MPa;in future this will rise to 180 MPa.The common-rail system allows a future reduction in exhaust-gas emissions by introducing pre-injection events or multiple injection events and also attenuating combustion noise significantly.Multiple injection events of up to five per injection cycle can be generated by triggering the highly rapid-action switching valve several times.The nozzle-needle closing action is hydraulically assisted to ensure that the end of injection is rapid.(5)Control and Regulation.The engine control unit detects the accelerator-pedal position and the current operating states of the engine and vehicle by means of sensors.The data collected includes:

① Crankshaft speed and angle;② Fuel-rail pressure;③ Charge-air pressure:

④ Intake air, coolant temperature, and fuel temperature: ⑤ Air-mass intake: ⑥ Road speed, etc.The electronic control unit evaluates the input signals.In sync with combustion, it calculates the triggering signals for the pressure-control valve or the metering unit, the injectors, and the other actuators(e.g.the EGR valve, exhaust-gas turbocharger actuators, etc.).The injector switching times, which need to be short, are achievable using the optimized high-pressure switching valves and a special control system.The angle/time system compares injection timing, based on data from the crankshaft and camshaft sensors, with the engine state(time control).The electronic diesel control(EDC)permits a precise metering of the injected fuel quantity.In

addition, EDC offers the potential for additional functions that can improve engine response and convenience.The basic functions involve the precise control of diesel-fuel injection timing and fuel quantity at the reference pressure.In this way, they ensure that the diesel engine has low consumption and smooth running characteristics.Additional open-and close-loop control functions perform the tasks of reducing exhaust-gas emissions and fuel consumption, or providing added safely and convenience.Some examples are:

① Control of exhaust-gas recirculation;② Boost-pressure control;③ Cruise control;

④ Electronic immobilizer, etc.(6)Control Unit Configuration.As the engine control unit normally has a maximum of only eight output stages for the injectors, engines with more than eight cylinders are fitted with two engine control units.They are coupled within the “ master/slave ” network via an internal, high-speed CAN interface.As a result, there is also a high microcontroller processing capacity available.Some functions are permanently allocated to a specific control unit(e.g.fuel-balancing control).Other can be dynamically allocated to one or many of the control units as situation demand(e.g.to detect sensor signals).