The tgss prevents leakage of air into or radioactive steam out of the turbine shaft and turbine valves. The dry gas may be air such as dehydrated instrument air, or dry nitrogen. Gland sealing steam supply system for steam turbines. Api standard 612 petroleum, petrochemical, and natural gas industries. Overlooked gland seal can be big trouble power services group. To drain out the condensate producing due to cooling of the gland steam drain are also provided. Gland steam must have appropriate temperature and pressure which must be controlled during startup. Dec 03, 2015 the steam turbine gland steam seal system is designed to keep steam from leaking out of the turbine and to prevent air from leaking into the turbine. Fire resisting fluid acknowledgements glossary bibliography biographical sketch summary steam turbines consist essentially of a casing to which stationary blades are fixed on the. Overlooked gland seal can be big trouble december 3, 2015 in steam turbine tips by psgweb. This publication is concerned only with the special carbon gland rings for steam turbine applications and similar glands sealing hot or dry gases.
A game changer for gland sealing in general purpose steam. Nov 19, 2016 arrangement is done vent the excess steam. To sealing turbine before pulling condensate vacumn before start up, gland sealing steam is extracted from the live steam system or auxiliary steam systeam and decreased both pressure and temperature pressure. Steam program service evaluation for power generation. Gland steam is steam supplied to the labyrinth glands of the low pressure turbine to prevent air entering in the exhaust side, which disturbs the vacuum 50 mbar absolute in the condenser. Rotor extended outside the casing at both side and rear side. Simultaneously, gland steam system is started to prevent air inleakage. Small heat exchanger used to condense the steam that leaks past the first section of seals on the shaft of a steam turbine.
C61207 this standard specifies the minimum requirements for. The first question faced by the design engineer is which standard steam turbine as to be selected either api 611 or api 612. Ep0268423a2 gland sealing steam supply system for steam. The steam turbine gland steam seal system is designed to keep steam from leaking out of the turbine and to prevent air from leaking into the turbine. For understanding the gland sealing system first we have to understand why it is required so there are two main reason. The technical data is taken from the bhel steam turbine unit, hyd. Nov 10, 2016 function of labyrinth packing in steam turbine.
Gland steam system a high pressure steam turbine is having a sealing gland, where, the turbine rotor penetrates the casing of the turbine. In case of turbines with cooling water preheating and lowpressure lp. A carbon ring has three segments held together with a garter spring. A gland sealing steam supply system according to claim 6, wherein said system further includes a gas turbine, and a waste heat recovery boiler used for recovering heat of a waste gas from said gas turbine and having a highpressure steam generating portion consisting of an economizer, a highpressure steam generator and a superheater, and a low. A gland sealing steam supply system according to claim 6, wherein said system further includes a gas turbine, and a waste heat recovey boiler used for recovering heat of a waste gas from said gas turbine and having a highpressure steam generating portion consisting of an economizer, a highpressure steam generator and a superheater, and a low. Dear all i am working as a head engineer at a sulphuric acid plant.
Prior to supplying steam to the turbine, the steam supply pipelines have to be drained and heated up. Function and system layout the two functions of the turbine glands and seals are. The large, turbine gland sealing systems are basically self sealing, in the sense at a load 40% hp steam coming out from the hpt side could be enough to seal the same on the lpt side. Turbine gland seals are provided to eliminate the possibility of leakage of steam from the turbine through the turbine glands under pressure and ingress of atmospheric air into the turbine under vacuum.
Our predefined spare parts catalogs for standard spares and the ge rapid reverse engineering process ensure that necessary parts are delivered to site whenever they are needed. The large, turbine gland sealing systems are basically selfsealing, in the sense at a load 40% hp steam coming out from the hpt side could be enough to seal the same on the lpt side. When the steam turbine runs, the rotor rotates with a high speed, while the cylinder, partitions and other parts are fixed and static. The gland steam condenser collects air and steam mixture, condenses the steam, and discharges the air leakage. Gland condensers ab progetti vacuum systems steam jet. While the leakage of steam causes a reduction in cycle efficiency, entry of cold air may cause thermal shock to hot turbine internals.
General purpose steam turbine reliability by john b. Gland sealing system complete heat exchanger steam. Specifically, if the turbine exhausts into a vacuum system, it is necessary to inject sealing steam into the seals in order to keep the low pressure end of the turbine from drawing in atmospheric air. Up to nearly 40% load lowpressure auxiliary steam is supplied to the sealing header to seal hpt, ipt, and lpt glands. Hp and lp turbines and onto the gland steam condenser. Ger3705 ge steam turbine design philosophy and technology. The condensate is recovered and introduced into the system via the main condenser.
Sealing is a combination of close clearances between the shaft and carbon ring, and the side of the carbon ring against the. Find gland sealing system steam turbines related suppliers, manufacturers, products and specifications on globalspec a trusted source of gland sealing system steam turbines information. Turbine gland steam system the turbine gland steam system tgss provides steam to the turbine glands and the turbine valve stems. While selecting a steam turbine as a driver for compressors or pumps for refinerypetrochemical industries. Thus for a gland with a given number of restrictions, there is an associated pressure ratio that produces the maximum leakage through the gland. Re utilization of gland steam for optimized efficiency in. When casing pressure is lower than atmospheric, external steam is supplied via a letdown valve and desuperheater. The gland sealing system is designed to supply steam to seal the turbine shaft glands at all operating conditions and to extract leakoff steam from the glands.
A small flow of dry gas is introduced into the bear. Lately, in one of our steam turbines we are experiencing loss of vacuum, which we have attributed to the gland steam condenser malfunction. Causes and solutions steam turbine rotors bend during operation, but the bearing and supports are designed to keep the static and dynamic forces under control. Overlooked gland seal can be big trouble power services. Us4793141a gland sealing steam supply system for steam. Simultaneously, gland steam system is started to prevent air in leakage.
Typically, the steam end and exhaust end gland boxes each carry four to five carbon rings, though some may have more. When casing pressure is higher than atmospheric the gland sealing steam passes outward toward the gland steam condenser through a spillover valve. Gland type flexible metallic packing water packing carbon packing a watersealed glands and labyrinth seals as used on the highpressure end of condensing turbines. Introduction during the past 50 years the gland ring has become a standard method for sealing medium and large diameter shafts. Dec 18, 2015 place the gland sealing steam system in service. Shaft sealing of steam turbines general electric company. The rings seal against lands machined into the gland housing. A gland leakoff condenser must be included to condense the gland steam. Lp turbine turbine system seal steam system the penultimate section of each gland is supplied with steam from gland steam header, which is maintained at a pressure of 1. Aug 19, 20 to alleviate this pressure the dump valve begins to open and regulates the gland sealing steam system by dumping this excess pressure. Water contamination of steam turbine lube oilshow to avoid it 53 in the writers opinion, the best way of coping with this problem is to install a dry gas purge at the bearing housing seals. As its the usual the acid production is coupled with power generation steam turbine driven generators. What the function of gland steam condenser answers. Labyrinth packing an overview sciencedirect topics.
Gland steam sealing system for steam turbine youtube. Schofield ge company schenectady, ny introduction the need to provide stateoftheart products for a diverse and everchanging market is the chal lenge facing steam turbinegenerator manufactur ers in the 90s. Conventional gland sealing in general purpose steam turbines is accomplished with carbon rings. How does the steam turbine gland sealing system work. In this post, we will see the difference between api 611 and api 612. Condensate from the main condenser is usually the source of cooling water for the gland condenser and the main air ejectors.
Gland steam condenser posted in industrial professionals. The turbine gland sealing system tgss prev ents the escape of steam from the turbine shaft and casing penetrations and the glands of main steam stop and control valves. To alleviate this pressure the dump valve begins to open and regulates the gland sealing steam system by dumping this excess pressure. A gland seal system can be as simple as a spray chamber, loop seal and a steam ejector or as complex as surface condensers, air blowers or vacuum pumps. This dumped gland sealing steam and any leak off steam from the lower pressure glands is not wasted but piped under a slight negative pressure back to the gland steam condenser. Gland condensers vacuum systems steam jet ejectors. Under certain conditions the gland is sealed by an auxiliary steam supply, and under other conditions the gland is self sealed by. This system also prevents air leakage into the low pressure turbine glands. When casing pressure is higher than atmospheric the gland sealing steam passes outward toward the gland steam condenser through a. A gland seal system can be as simple as a spray chamber, loop seal and a steam ejector or as complex. As turbine exhaust is connected to a condenser which is operated below atm pressure so there are chances of air ingres or va.