汽机培训教材9

喀北电站汽机资料喀北电站汽机资料GLAND SEAL SYSTEM喀北电站汽机资料喀北电站汽机资料n在汽轮机转子穿过外缸的部位，必须采取措施用以防止外部空气在汽轮机转子穿过外缸的部位，必须采取措施用以防止外部空气漏入汽缸，从而影响排汽缸的真空，同时也必须防止汽缸内蒸汽漏入汽缸，从而影响排汽缸的真空，同时也必须防止汽缸内蒸汽漏出汽缸，漏入前轴承箱容易造成油中带水，漏至汽机房破坏汽漏出汽缸，漏入前轴承箱容易造成油中带水，漏至汽机房破坏汽机房环境。汽轮机的汽封系统就是为了完成这一功能而设置的。机房环境。汽轮机的汽封系统就是为了完成这一功能而设置的。nMeasures must be taken at the portions where the turbine rotor passes through the outer casing to prevent the air leakage from outside into the casing and affect the vacuity of the exhaust hood.In the meantime,the steam inside the casing must also be prevented from its leakage to the outside,especially,to the front bearing box to lead to a mixing of the lubrication oil with water and to the turbine house to deteriorate its environmental conditions.The gland seal system of a steam turbine is furnished just for such a purpose.喀北电站汽机资料喀北电站汽机资料辅助蒸汽辅助蒸汽母管母管Steam seal cooler喀北电站汽机资料喀北电站汽机资料Steam seal cooler喀北电站汽机资料喀北电站汽机资料Steam seal cooler汽汽 封封 系系 统统 图图喀北电站汽机资料喀北电站汽机资料n本系统是上下压分开供汽的汽封系统本系统是上下压分开供汽的汽封系统.nThe present system is a gland seal system capable of supplying steam to HP and LP cylinder separately developed.喀北电站汽机资料喀北电站汽机资料n系统中主要设备有：高压轴封供汽调节站、低压轴封供汽调节站、高压喷水减温调节站、低压喷水减温调节站、各种截止阀、疏水阀等，连同汽封冷却器、疏水扩容器等设备，共同构成了该机组汽封系统。该系统能够维持汽封供汽母管的压力在0.1070.11MPa(A)之间，供汽温度在121150之间，控制局部可根据实际情况接入控制室，通过DCS系统调节各执行机构动作。nThe system mainly includes the following main equipment items:HP gland seal steam supply regulating station,LP gland seal steam supply regulating station,HP water spray desuperheating regulating station,LP water spray desuperheating regulating station,various cut-off valves and drain valves,gland seal coolers and drain flask tanks etc.It can exercise a function of maintaining the steam pressure inside the gland seal steam supply mainline between 0.107 Mpa and 0.11 Mpa,the steam temperature between 121 and 150.The control signals can be sent to the control room according to the specific cases and then control the action of various actuators through the DCS system.喀北电站汽机资料喀北电站汽机资料n转子汽封转子汽封 Gland Seal of Rotorn在汽缸两端装有汽封体和汽封圈，汽封圈上汽封齿环绕转子，外表仅留有为防止在汽缸两端装有汽封体和汽封圈，汽封圈上汽封齿环绕转子，外表仅留有为防止在运行过程中发生接触的间隙。在运行过程中发生接触的间隙。nGland casings and sealing rings are equipped at both ends of the cylinder and the teeth on the seal rings surround the rotor with a clearance being kept to prevent any contact between the said teeth and the rotor surface during the turbine in operation.n在汽轮机启动时，凝汽器抽真空，汽缸内的压力低于大气压力，供至在汽轮机启动时，凝汽器抽真空，汽缸内的压力低于大气压力，供至“A腔室的腔室的汽封蒸汽在一侧通过汽封漏入汽轮机汽缸内，在另一侧漏入汽封蒸汽在一侧通过汽封漏入汽轮机汽缸内，在另一侧漏入“B腔室，汽封抽汽腔室，汽封抽汽器正常运行，使器正常运行，使“B腔室维持压力稍低于大气压力，因而空气通过端汽封漏入腔室维持压力稍低于大气压力，因而空气通过端汽封漏入“B腔室，形成汽气混合物，通过一个与汽封抽汽器相连的接口，从腔室，形成汽气混合物，通过一个与汽封抽汽器相连的接口，从“B腔室腔室被抽出。被抽出。(见图见图1)nDuring startup of the steam turbine,the condenser is evacuated and the pressure in the cylinders is lower than the atmospheric pressure.The steam supplied to the“A chamber of the gland seal is leaked to the cylinder of the turbine at one side and to“B chamber at another side.If the air ejector for the gland seals is in normal operation to maintain the pressure in“B chamber slightly lower than the atmospheric pressure,the air is leaked into the“B chamber through the gland seal at the end,forming a steam and air mixture.Then the mixture is evacuated from“B chamber via a port connected with the air ejector for the gland seals(see Fig.1).喀北电站汽机资料喀北电站汽机资料喀北电站汽机资料喀北电站汽机资料n随着机组负荷的不断提高，高中压缸两端的压力逐渐增加，但因“C腔室与2号低压加热器(JD2)相连，所以高中压汽封的“A腔室始终保持送汽状态；由于低压缸压力仍保持一定的真空状态，所以低压汽封的“A腔室始终保持送汽状态。当除氧器能供汽时，那么切到正常运行系统，即由除氧器来供汽(见图2)。nWith a continuous increase of the load of the steam turbine,the pressures at both ends of HP and IP cylinder will gradually increase.As the“C chamber is connected to the 2#LP heater(JD2),so the“A chambers in HP and IP cylinder is always kept in a steam-supplying state.Due to the LP cylinder being maintained at a vacuum state,the“A chamber of LP gland seals is always kept in a steam-supplying state.When the deaerator has an ability to supply steam,the normal operation system shall be put into service,i.e.supplying steam by the deaerator(see Fig.2).喀北电站汽机资料喀北电站汽机资料喀北电站汽机资料喀北电站汽机资料n蒸汽压力温度控制装置蒸汽压力温度控制装置 Steam Pressure and Temp Controllern在汽轮机启动和低负荷运行状态下一般低于在汽轮机启动和低负荷运行状态下一般低于40%负荷，辅助汽源经过轴封压力调节阀减负荷，辅助汽源经过轴封压力调节阀减压及喷水减温调节阀控制的减温器减温后，向汽封母管供蒸汽。随着负荷不断提高压及喷水减温调节阀控制的减温器减温后，向汽封母管供蒸汽。随着负荷不断提高(约约40%负荷左右负荷左右)，当除氧器的汽平衡室压力建立起来时，那么切换到正常运行系统，即由除氧器，当除氧器的汽平衡室压力建立起来时，那么切换到正常运行系统，即由除氧器来供汽。供汽母管配有热电偶及压力变送器来供汽。供汽母管配有热电偶及压力变送器(设计院选配设计院选配)，母管的温度和压力变化是通过与，母管的温度和压力变化是通过与其相连的热电偶和压力变送器传递的，信号传到主控制室，由主控制室其相连的热电偶和压力变送器传递的，信号传到主控制室，由主控制室DCS系统完成对调节系统完成对调节阀的温度和压力控制。阀的温度和压力控制。nUnder the condition of the steam turbine operating in the startup state and at a low load(generally lower than 40%of the rated load),the auxiliary steam source shall supply steam to the gland seal steam mainline after the steam pressure has been reduced by the gland seal steam pressure regulating valve and the steam temperature has been desuperheated by an attemperator controlled by the water spray desuperheating regulating valve.With a continuous increase of the load(to about 40%of the rated load),when a steam pressure is established in the steam equilibrium chamber of the deaerator,the normal operation system shall be put into operation,i.e.the steam to the gland seals shall be supplied by the deaerator.The steam supply mainline shall be equipped with thermocouples and pressure transmitters(selected by an electric-power designing institute).The signals showing the change of steam temperature and pressure in the mainline are transmitted by the thermocouples and pressure transmitters to the main control room and then the DCS control system shall exercise a control over the steam temperature and pressure by use of the regulating valve based on the signals.喀北电站汽机资料喀北电站汽机资料n汽封压力调节阀能在所有运行条件下以其DCS系统的给定压力向各汽封供汽。轴封送汽调节阀压力给定值为0.1070.11MPaA。因母管压损未知可按实际情况调整nThe gland seal steam pressure regulating valve shall supply steam to various gland seals at a pressure set by the DCS control system at all the operating conditions.The gland seal steam pressure set point by the regulating valve ranges from 0.1070.11MPaA(due to the pressure loss in the mainline being unknown,one can make an adjustment according to the specific case).喀北电站汽机资料喀北电站汽机资料n供汽母管蒸汽温度主要是由减温器来控制的，减温水来自于凝结水泵，减温水量是由减温水调节阀来控制的，温度信号取自供汽母管的温度，将温度信号转换为420mA电信号送到主控制室，由DCS系统来控制减温水调节阀的执行机构，使供汽母管蒸汽温度控制在121150之间。nThe steam temperature in the steam supply mainline is mainly controlled by the desuperheater with the desuperheating water coming from the condenstate water pump and the desuperheating water quantity being controlled by the desuperheating water regulating valve.The temperature signal is obtained from the steam supply mainline and then converted into a 420mA electronic signal which is sent to the main control room.Based on the electronic signal,the DCS control system takes control over the actuator of the desuperheating water regulating valve,maintaining the steam temperature in the steam supply mainline between 121 and 150.喀北电站汽机资料喀北电站汽机资料n汽封冷却器汽封冷却器 Gland Coolern汽封冷却器以稍低于大气压力即汽封冷却器以稍低于大气压力即0.095MPaA的压力接收阀杆及汽封的压力接收阀杆及汽封“B腔室的漏汽，腔室的漏汽，因此保证因此保证“B腔室一直保持负压。腔室一直保持负压。nThe gland seal cooler receives the steam leakage from the stems and the gland seal“B chamber by operating at a pressure of 0.095MPaA slightly lower than the atmospheric pressure,thus keeping the“B chamber being always at a negative pressure.喀北电站汽机资料喀北电站汽机资料n蒸汽过滤器蒸汽过滤器Steam Filtern为了防止外部物质进入汽封和引起转子的损坏，在每为了防止外部物质进入汽封和引起转子的损坏，在每个汽封的供汽管道中使用了蒸汽过滤器，过滤器个汽封的供汽管道中使用了蒸汽过滤器，过滤器“Y形支管是水平安装或置于管道的顶部，所以能够自形支管是水平安装或置于管道的顶部，所以能够自行排空。行排空。nTo prevent foreign matters from entering into the gland seals and causing a damage to the rotor,the steam filters are used in every steam supply pipelines of the gland seals and the“Y-shaped branch pipes shall be installed horizontally or placed on the top of the pipes,thus ensuring an air vent by the filters themselves.喀北电站汽机资料喀北电站汽机资料汽封系统的运行汽封系统的运行 Operation of Gland Systemn冷态启动冷态启动Cold-state Startupn1.在汽轮机和进汽管道所有疏水阀翻开的情况在汽轮机和进汽管道所有疏水阀翻开的情况下，投入盘车。下，投入盘车。nUnder the condition that all the drain water valves on the steam turbine and steam intaking pipelines are opened,the turning gear shall be put into service.喀北电站汽机资料喀北电站汽机资料n2.建立通过凝汽器的水循环。nEstablish a water circulation through the condenser.n3.启动凝结水泵并建立通过汽封抽汽器的冷却水流。nStart up the condensate water pump and establish a cooling water flow rate through the air ejector of the gland seals.喀北电站汽机资料喀北电站汽机资料n4.开启汽封抽汽器水室上的放气口，直至全部残留气体排入大气。nOpen the air vent on the water box of the air ejector of the gland seals until all the residual gas is discharged to the atmosphere.n5.确认疏水扩容器壳体的疏水系统对凝汽器是翻开的。nMake sure that the drain system inside the enclosure of the drain water flash tank is opened to the condenser.n6.确认汽封抽汽器水位报警器在运行中，且仪表截止阀是翻开的。nMake sure that the water level alarm of the air ejector for the gland seals is in operation and the cut-off valves of the instruments are opened.喀北电站汽机资料喀北电站汽机资料n7.确认每个汽封压力、温度调节站及旁路阀处于关闭状态。nMake sure that every gland seal steam pressure and temperature regulator stations and bypass valves are in the closing state.n8.确认启动汽源温度必须具有不小于14的过热度。nMake sure that the temperature of the startup steam source compulsorily has a degree of superheat of not less than 14.n9.确认调节阀入口的供汽管道中无水。nMake sure that there is no water in the steam supply pipeline to the inlet of the regulating valve.喀北电站汽机资料喀北电站汽机资料n10.启每个调节阀两侧的手动截止阀。nOpen the manually-operated valves at both sides of each regulating valves.n11.汽封系统在冷态启动状态时，辅助汽源向各个汽缸前后汽封供汽，蒸汽通过轴封压力调节阀减压，再通过减温器减温到121150向上下压前后轴封供汽。如果除氧器能供汽，那么切到正常运行系统。nDuring a cold-state startup of the gland seal system,the auxiliary steam source shall provide steam to the gland seals in the front and at the rear of various cylinders.The steam pressure is reduced by the gland seal steam pressure regulating valve and the steam temperature is desuperheated to 121 and 150 by an attemperator.Then,the steam is supplied to the HP and LP front and rear gland seals.If the deaerator has an ability to supply the steam,then the normal operation system shall be put into service.喀北电站汽机资料喀北电站汽机资料n12.当汽封供汽母管压力建立并暖管后，立即启动汽封抽汽器。nWhen the steam pressure in the steam supply mainline of the gland seals is established and the said mainline is warmed up,one shall immediately start up the air ejector for the gland seals.n13.确认汽缸的每个汽封腔室均有低度真空。nMake sure that each chamber of the gland seals for the cylinders has a vacuity at a low degree.喀北电站汽机资料喀北电站汽机资料n14.确认各汽封腔室内蒸汽没有漏入大气，如果发现漏汽，那么提高汽封抽汽器真空，或调整压力调节阀或各送汽支路上的送汽截止阀，调节各截止阀开度，以降低汽封母管的蒸汽压力，直至停顿向外部漏汽。nMake sure that the steam in various gland seal chambers does not leak to the atmosphere.If any leakage of steam is found,the vacuity maintained by use of the air ejector shall be enhanced or the pressure regulating valve or the cut-off valves on various branch lines for steam supply shall be adjusted or the opening degrees of various cut-off valves shall be regulated to reduce the steam pressure in the gland seal steam mainline until the said leakage of steam to the outside is stopped.喀北电站汽机资料喀北电站汽机资料n15.检查汽封供汽母管的温度，检查高压缸内壁温度与汽封腔室内蒸汽温度之差值，确保差值小于110，确保后汽封送汽腔室内蒸汽温度在121150之间，检查汽封蒸汽管路疏水是否通畅。nInspect the temperature in the gland seal steam supply mainline,inspect the temperature difference between the inner wall temperature of the HP cylinder and steam in the gland seal chambers,ensure the said difference to be less than 110 and the steam temperature in the rear gland seal steam supply chamber to be between 121 to 150.Inspect the gland seal steam pipelines to see whether the drain inside flows freely.喀北电站汽机资料喀北电站汽机资料n16.关闭凝汽器的真空破坏门，启动抽气设备，并在凝汽器内建立尽可能高的真空，在每个汽封建立起最大流量之前，所需的汽封蒸汽量随凝汽器真空的改善而增加。nClose the vacuum breaking valve,start up the air ejector equipment and establish a vacuity as high as possible in the condenser.Prior to an establishment of a maximum flow rate in each gland seals,the steam amount necessary for the gland seals will increase with an increase of the vacuity in the condenser.喀北电站汽机资料喀北电站汽机资料n17.当负荷逐渐增加时，来自除氧器的蒸汽可以满足高、低汽封供汽时，那么辅助汽源供汽切换到除氧器供汽。这样高中压汽封系统与低压汽封系统相互独立，整个系统相对稳定。nWhen the load gradually increases and the steam flow rate from the deaerator can meet the steam amount required by the HP and IP gland seal system,the steam can be switched over from supplied by the auxiliary steam source to supplied by the deaerator.In such a case,the HP and IP gland seal system are independent from the LP gland seal system and the whole system is relatively stable.喀北电站汽机资料喀北电站汽机资料控制降负荷控制降负荷Control Load Reductionn在控制降负荷时，汽封母管的蒸汽压力高于0.107MPa(A)，那么汽封系统维持正常状态，高、低压汽封供汽由除氧器供给；当汽封母管压力低于0.107MPa(A)时，即除氧器的汽源不能保证母管压力时，改由辅助汽源供汽。nWhen the load reduction is controlled and the steam pressure in the gland seal steam mainline is higher than 0.107 Mpa(A),the gland seal system is kept in a normal operation state and HP and LP gland seal steam is supplied by the deaerator.When the steam pressure in the gland seal steam mainline is lower than 0.107 Mpa(A),i.e.the steam from the deaerator can not maintain the pressure in the mainline,then the steam shall be supplied by an auxiliary steam source.喀北电站汽机资料喀北电站汽机资料汽轮机停机汽轮机停机Turbine Shutdown只要存在着保持汽缸内真空的必要，就必须向汽轮机各汽封提供密封蒸汽，在凝汽器的抽气设备停顿运行和凝汽器的真空完全消失以前，不得切断汽封供汽，否那么冷空气流入会使转子外表金属急剧冷却，而且还会导致热的静止的汽封体变形。As long as a need for keeping a vacuity in the cylinders exists,one shall supply steam to various gland seals of the turbine.Prior to the stoppage of the air extraction equipment of the condenser and a full loss of vacuity in the condenser,the steam supplied to the gland seals shall not be cut off,otherwise,cold air entering into the steam turbine would cause an abrupt cooling of the rotor surface metal and also result in a deformation of the hot and still gland casings.喀北电站汽机资料喀北电站汽机资料汽轮机停机顺序汽轮机停机顺序 Shutdown Sequence n1.在机组盘车和汽封供汽来自外部汽源的情况下，确认凝汽器真空已完全消失。nUnder the condition that the steam for maintaining the turbine turning and the gland seals is from the steam source at the outside,one shall make sure that the vacuity in the condenser has been fully lost.n2.关闭汽封冷却器风机。nClose the fan of the gland seal cooler.n3.关闭各汽封压力调节阀两侧的手动截止阀。nClose various manually-operated cut-off valves at both sides of the gland seal steam pressure regulating valve.喀北电站汽机资料喀北电站汽机资料n在切断汽封冷却器的风机后，应立即关闭上述阀门，在汽封体内无真空的情况下，汽封供汽的投入导致蒸汽漏入大气，这些蒸汽会进入润滑油中，并凝结成为污染杂质，积存在油箱中。nAfter the fan of the gland seal cooler has been stopped,one shall immediately close all the above-mentioned valves.Under the condition that the seal casing is at zero vacuity,if the gland seals are supplied with steam,the latter will be escaped to the atmosphere and also to the bearing box,mixed with the lubrication oil and coagulated to pollutants and deposited in the oil tank.喀北电站汽机资料喀北电站汽机资料n热态启动热态启动Hot-state Startupn热态启动状态，机组转子温度接近满负荷运行工况下的转子温度，此时热态启动状态，机组转子温度接近满负荷运行工况下的转子温度，此时所有阀门状态同冷态启动，只是增加一股热态启动汽源所有阀门状态同冷态启动，只是增加一股热态启动汽源(P=1.0MPa，T=450)，通过高温电动、手动截止阀后，向图，通过高温电动、手动截止阀后，向图2中的高压前汽封的中的高压前汽封的“D腔室送汽。其它同冷态启动送汽，如果除氧器能供汽，那么切到正常腔室送汽。其它同冷态启动送汽，如果除氧器能供汽，那么切到正常运行系统。运行系统。nHot-state startup status:the rotor temperature of the steam turbine shall approximate to that at the full-load operation condition.In such a case,the states of all the valves are same as the cold-state startup and a hot-state steam source(P=1.0MPa，T=450)shall be additionally provided.The steam shall be fed to the“D chamber in HP front gland seal as shown in Fig.2 after passing through high temperature electrically-operated and manually-operated cut-off valves.The others are same as those for supplying steam to the turbine during its cold-state startup.If the deaerator can be supplied with steam,then the normal operation system shall be put into service.喀北电站汽机资料喀北电站汽机资料汽封系统运行的限制汽封系统运行的限制 Limitation of Gland Seal System Operationn1.汽封供汽必须具有不小于14的过热度。nThe steam supplied to the gland seals must have a degree of superheat not less than 14.n2.盘车之前不得投入汽封供汽系统，以免弯轴。nBefore turning the steam turbine,the gland seal steam supply system shall not be put into operation for fear of the rotor sagging.n3.低压汽封供汽温度要在121150之间。nLP gland seal steam supply temperature shall be between 121 and 150.喀北电站汽机资料喀北电站汽机资料n4.为了防止汽封部位由于热应力而造成转子损坏，当机组在启动和停机时，要尽量减少汽封蒸汽和转子外表间的温差。nTo prevent the thermal stress at the gland seal portions to damage the rotor,during the startup and shutdown of the turbine,the temperature difference between the gland seal steam and the rotor surface shall be minimized as possible.喀北电站汽机资料喀北电站汽机资料 报警值报警值Alarm valuen1.后汽封蒸汽温度121报警n 165报警nThe rear gland seal steam temperature 121 give out an alarmnThe rear gland seal steam temperature 165 give out an alarmn2.汽封母管压力0.098MPa报警nGland seal main line steam pressure0.098Mpa give out an alarmn3.汽封冷却器压力0.097MPa报警nGland seal steam cooler steam pressure0.097Mpa give out an alarm喀北电站汽机资料喀北电站汽机资料演讲完毕，谢谢观看！