H2 oil describe the power supply to the emergency seal. This may be due to installation or deposit formation. A dp between the seal oil and hydrogen gas is maintained to prevent hydrogen leakage see figure ix91. It is expected that the entrained air liberated from the seal oil, along. Generator seal oil system thermal power plant basic to. The seal oil system may be a completely separate oil system, however in most cases it is apart of the compressor main lube oil system. Seal oil enters the seal housing at a pressure about 5 psig above the machine hydrogen gas pressure.
The vacuum pump is drawing air, water vapor and hydrogen gas. Also, provides a trapvent system to prevent the release of hydrogen into the turbine generator lube oil system and building atmosphere. Advanced sealing technology for hydrogen compressors hooshang heshmat, phd mohawk innovative technology, inc. It is a free energy carrier that can be produced by many energy sources. Basic ac electrical generators 3 as the south pole moves away, the current in the winding decreases, returning to zero again when neither pole is close to the winding. Emergency seal oil pump relief valve is set at 80 psig and returns oil to pump suction line. A differential pressure between the seal oil and hydrogen gas must be maintained in order to avoid hydrogen leakage. Aug 30, 20 effects of hydrogen seal deposits hydrogen seal issues are primary initiated by reduced clearances. Dec 09, 2015 since the hydrogen seal oil system has parallel cartridge filters located downstream of the cuno filter, the cuno filter was returned to service without internal components. A seal oil system continuously provides cool, clean seal oil to the seals at the proper differential pressure over seal gas reference pressure, temperature, and flow rate. Hydrogen sulfide is a byproduct of processing natural gas and refining highsulfur crude oils. Most hydrogen cooled generator are incorporate the seal oil system, just because to avoid the contact between and air and hydrogen generally pressure of hydrogen in generator around 4bar.
Seal oil pressure kept 38psid greater than generator h2 pressure. The hydrogen seal oil lube oil system was replenished and the unit was returned to service on november 20, 2010, at 2020. Hydrogen leaks occur at the generator bearings and shaft seals, in the seal oil supply system and from the hydrogen supply piping, mechanicals and puritypurging cabinet. The purpose of the seal oil system is to keep the compressed gas from entering the bearing assembly and escaping from the compressor to the atmosphere. Flow to 1,000,000 kgday pressure rise from 300500 up to 1,2001,500 psig contaminantfreeoilfree category 2005 status fy2012 fy2017 reliability low improved high energy efficiency 98% 98% 98% leakage undefined tbd hydrogen leaks occur at the generator bearings and shaft seals, in the seal oil supply system and from the hydrogen supply piping, mechanicals and puritypurging cabinet. Sulfur recovery refers to the conversion of hydrogen sulfide h 2s to elemental sulfur. Generator hydrogen seal oil system must be in operation any time there is hydrogen or co2 in the generator casing where is hydrogen used in the generator hydrogen system stored. Title operate generator cooling and seal oil systems from. Systems are designed with instrumentation to monitor seal condition. Below are several examples of problematic hydrogen seals. Seal oil is supplied by the msop through filters and pressure diffential valve. Turbo gen services introduction function seals both ends of the generator shaft against hydrogen. K abstract the essential facts about the nature of the hydrogen embrittlement of steels have now been known for 140 years. A system provided to remove air from the seal oil into the hydrogen side of the generator seal is popularly called a scavengingpurging system.
Vented h2 to allow for securing h2 seal oil system 59 58. Dec 15, 2012 generator seal oil system system functions. A hydrogen cooled generator having a system for diagnosing problems associated with a seal oil system. Varnish solutions in hydrogen seals turbomachinery. Increase power output and reduce hydrogen seal oil system. Tuthill kinney rotary piston vacuum pumps have been running for years in the hydrogen seal oil application in power stations. Cause of the event the root cause of this failure was that during past maintenance on the air side seal oil strainer, the graded. Us5474304a seal oil supply system using differential. Given a crosssectional diagram of a typical generator hydrogen seal. In accordance with the present invention, a seal oil system is provided for supplying seal oil to the seal plates of a gastight turbine generator both for normal operation and backup operation. Sep 22, 2011 the shaft seals 16, seal oil and detraining tank 20 thus form a seal oil system that prevents the escape of hydrogen gas.
A basic layout of the seal oil system there are two chambers on the shaft. The oil seal system consists of a storage tank, pumps. The oil seal system consists of a storage tank, pumps, filters, and pressure controls, all skid mounted. Operation of the seal oil system with the bearing oil header out of service may be performed during outages when the stator is not pressurized with hydrogen provided the following additional criteria are met. Since hydrogen, with a molecular weight of 2, has such a high propensity to leak, with potentially devastating results, it is imperative that a piping. Fuel oil system sulfur dioxide scrubber systems fly ash system lubricating oil system water demineralizer treatment system generator hydrogen and seal oil system mechanicalseal division. Associated gases released during oil gas production mainly contain natural gas. Basic seal oil systems engineering photos,videos and. There is also an emergency dc motor driven pump to provide the critical oil in the event of a turbine trip where ac power is not available. Both air and hydrogen is vented from oil in separate sections. Us20110231111a1 turbinegenerator hydrogen seal oil. Mar 30, 2015 seal oil system presentation free download as powerpoint presentation. Bhadeshiaa amaterials science and metallurgy, university of cambridge,u. It receives makeup oil from the bearing lubricating oil system.
Pressure relief valves on the discharge side of each seal oil pump relieves back to seal oil system. State the purpose of the generator hydrogen seal oil system. The seal oil that flows into the hydrogen side of the seal area is generally passed to a vessel known as an enlargement tank. Steam turbinegenerator overhaul and inspection guidelines. Nov 15, 1977 in accordance with the present invention, a seal oil system is provided for supplying seal oil to the seal plates of a gastight turbine generator both for normal operation and backup operation. The purpose of the seal oil system is very similar to the lube oil system and many times they are a combined system. Generator seal oil system thermal power plant basic to knowledge lesson 35. Centrifugal compressor wet seals high pressure seal oil circulates between rings around the compressor shaft oil absorbs the gas on the inboard side little gas leaks through the oil seal seal oil degassing typically vents methane to the atmosphere seal oil degassing may vent 40 to 200 scfminute.
Other systems integrate the seal oil system into the lube oil tank and use centrifugal pump. Only tuthill specially formulated vacuum pump oils ax or ku100 should be. It involves the ingress of hydrogen into a component, an event that can seriously reduce the ductility and loadbearing capacity, cause cracking and catastrophic brittle failures at stresses below the yield stress of susceptible materials. General description generator shaft seals are supplied with pressurized seal oil to prevent hydrogen escape at the shaft and the ingress of air in to the generator. Generator, unit hydrogen, seal oil, stator coolant, demin. A hermetic seal, usually a liquid seal, is employed. This is a type of deterioration which can be linked to corrosion and corrosioncontrol processes. Gek 107241 shaft sealing system 7h2 and 7fh2 generators keywords. Cool, clean oil from the turbine lubricating oil system is supplied to the hydrogen seal oil system storage tank. While this simple gen erator produces ac alternating current, the current produced is not very large since the strength of the magnetic field is not very large. The function of the seal oil control unit is to supply and maintain oil to the generator seals to contain hydrogen within the casing. Included is a shaft having a turbine end and a collector end. By keeping the hydrogen in the generators casing, the hydrogen will continue to cool the generators windings and rotor and do so in a safe. Oil seals mechanicalcontact and liquid film seals selfacting dry gas seals here is a brief description of each of these types of seals as well as recent improvements where applicable.
This presentation does not contain any proprietary, confidential or otherwise restricted information. Gek 107241 shaft sealing system 7h2 and 7fh2 generators author. A seal oil system continuously provides cool, clean seal oil to the seals at the proper differential pressure over seal gas. Hydrogen cooled generators require seal oil for their rotating shafts. Components dry gas seals dry gas seals, an alternative to isosleeve and isocarbon seals, eliminate the need for oil supply systems. Integrally geared centrifugal compressors represent the latest technology, offering significant advantages over outdated. Reduced hydrogen consumption, due to lower flow rates.
List and briefly explain six operational requirements of the generator hydrogen seal oil system. The air chamber a and the hydrogen chamber h the oil flowing through chamber a absorbs air whereas the oil flowing through chamber h takes in hydrogen. Role of vacuum pump in closedloop oil seal system the vacuum pump is drawing air, water vapor and hydrogen gas from the seal oil tank. The impact of reduced clearances and signs of impending seal failures are. The seal ring floats on the shaft, it does not rotate. Provide a seal between the generator housings and rotor shaft to maintain the pressurized hydrogen gas inside the generator. Ge hydrogen cooled 3d generator course overview duration. Labyrinth seals alabyrinth seal may be specified where the process to be sealed.
The system has seal oil storage tank, pumps, flow and pressure regulators. Stored in 2 banks outside 12 is normally operating, 11 in standby at 2000 psig reduced to 75 psig for our use. As long as this seal oil pressure in the annular gap exceeds the gas pressure in the generator, no hydrogen can escape from the generator housing. The oil was cleaned up and the air side seal oil strainer replaced. Labyrinth seals alabyrinth seal may be specified where the process to be sealed is at low to moderate pressures and relatively high leakage flows are. Approximately 90 to 95 percent of recovered sulfur is produced by the claus process. Low seal oil flow the typical flow rate in a large frame gas turbine may be 68gpm with total system flow. Definition seal oil pressure kept 38psid greater than generator h2 pressure. We are currently supplying our kd 50 direct drive rotary piston vacuum pumps to ge for this application. Vented h2 to allow for securing h2 seal oil system.
Hydrogen cooled generator 10 also includes a set of pressure, temperature and flow sensors that diagnose the seal oil system before more advanced symptoms such as increased hydrogen consumption become evident. This is a basic overview of piping requirements for a gaseous hydrogen system operating at ambient. D seal oil loop seal e backup supply from lub oil system f seal oil cooler g filters h bearing 7 hydrogen seal j bearing 8 hydrogen seal k generator l detraining chamber m gas trap oil is drawn from the seal tank by the a. General electric systems technology manual chapter 9. The seal oil system supplies seal oil to the seal plates of the gastight tg set and all types of operation irrespective of normal or emergency conditions. Each hydrogen cooled generator is served by a main and auxiliary seal oil pump driven by an ac motor. The oil from the seals flows back to the turbine lube oil system for cooling and cleaning. Hydrogen cools well, but safety is crucial power engineering.
Cleanliness is critical while the number of seal oil circuits per seal ring may vary from one design to another, the effect of. Engineers modelled the hydrogen seal systems and used the simulated results to identify the case of their system trips. However, even if the generator is not pressurized with hydrogen, seal oil must be supplied to the seals prior to placing the unit on the turning gear as the oil lubricates and cools the seals. The hydrogen seal oil system pumps then supply oil to the generator seals at 8 psig above generator gas pressure. Generator, unit hydrogen, seal oil, stator coolant, demin water. Advanced sealing technology for hydrogen compressors. In a seal oil system utilized to supply oil to shaft seals of a generator for preventing pressurized gas inside the generator from escaping through an interface of the generator shaft and the generator frame, wherein seal oil is supplied to said seals via a main supply line at a predetermined pressure, the improvement comprising at least one differential pressure accumulator including a barrel. Generator cooling and sealing system 2 linkedin slideshare. Since the hydrogen seal oil system has parallel cartridge filters located downstream of the cuno filter, the cuno filter was returned to service without internal components. Improved instrumentation and sensors, such as pressure switches, gaugestransmitters, pressure regulating valve and controls.
The most common conversion method used is the claus process. Seal oil system of generator in thermal power plant pump. Leistritz triple screw pumps, series l3nm, are responsible for the seal oil supply. Us20110231111a1 turbinegenerator hydrogen seal oil system. Clearance seals labyrinth and restrictive ring seals oil seals mechanicalcontact and liquid film seals selfacting dry gas seals here is a brief description of each of these types of seals as well as recent improvements where applicable. Separate pumps are used to feed seal oil to the air and hydrogen sides figure 2. Range includes but is not limited to function of seal oil, seal construction and operation, controls and instrumentation, detraining equipment. Cleanliness is critical while the number of seal oil circuits per seal. The purpose of the seal oil system in a combined cycle plant is to prevent hydrogen from escaping the generator in an uncontrolled manner and to collect the hydrogen that does escape with the seal oil. Generator seal oil supply system westinghouse electric. Stored in 2 banks outside 12 is normally operating, 11 in standby at. So, most of the hydrogen remain entrapped inside generator. The oil which contains air drains into an air defoaming tank where it settles and.
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