Design of Heat-Recovery Steam Generator Components in Gas ...
Heat Recovery Steam Generator
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M o d u l a r H R S G M o d u l a r H R S G G A H e a t r e c o v e r y s t e a m g e n e r a t o r F r o m W i k i p e d i a , t h e f r e e e n c y c l o p e d i a A h e a t r e c o v e r y s t e a m g e n e r a t o r o r H R S G i s a n e n e r g y r e c o v e r y h e a t e x c h a n g e r t h a t r e c o v e r s h e a t f r o m a h o t g a s s t r e a m . I t p r o d u c e s s t e a m t h a t c a n b e u s e d i n a p r o c e s s ( c o g e n e r a t i o n ) o r u s e d t o d r i v e a s t e a m t u r b i n e ( c o m b i n e d c y c l e ) . C o n t e n t s 1 H R S G s 2 P a c k a g e d H R S G s 3 V a r i a t i o n s 4 O n c e - t h r o u g h s t e a m g e n e r a t o r s ( O T S G ) 5 A p p l i c a t i o n s 6 M a n u f a c t u r e r s 7 B l o c k d i a g r a m 8 S e e a l s o H R S G s H R S G s c o n s s t o f f o u r m a j o r c o m p o n e n t s : t h e e c o n o m i z e r , e v a p o r a t o r , s u p e r h e a t e r a n d w a t e r p r e h e a t e r . T h e d i f f e r e n t c o m p o n e n t s a r e p u t t o g e t h e r t o m e e t t h e o p e r a t i n g r e q u i r e m e n t s o f t h e u n t . S e e t h e a t t a c h e d i l l u s t r a t i o n o f a M o d u l a r H R S G G e n e r a l A r r a n g e m e n t . M o d u l a r H R S G s c a n b e c a t e g o r i z e d b y a n u m b e r o f w a y s s u c h a s d i r e c t i o n o f e x h a u s t g a s e s f l o w o r n u m b e r o f p r e s s u r e l e v e l s . B a s e d o n t h e f l o w o f e x h a u s t g a s e s , H R S G s a r e c a t e g o r i z e d i n t o v e r t i c a l a n d h o r i z o n t a l t y p e s . I n h o r i z o n t a l t y p e H R S G s , e x h a u s t g a s f l o w s h o r i z o n t a l l y o v e r v e r t i c a l t u b e s w h e r e a s i n v e r t i c a l t y p e H R S G s , e x h a u s t g a s f l o w v e r t i c a l l y o v e r h o r i z o n t a l t u b e s . B a s e d o n p r e s s u r e l e v e l s , H R S G s c a n b e c a t e g o r i z e d i n t o s i n g l e p r e s s u r e a n d m u l t i p r e s s u r e . S i n g l e p r e s s u r e H R S G s h a v e o n l y o n e s t e a m d r u m a n d s t e a m i s g e n e r a t e d a t s i n g l e p r e s s u r e l e v e l w h e r e a s m u l t i p r e s s u r e H R S G s e m p l o y t w o ( d o u b l e p r e s s u r e ) o r t h r e e ( t r i p l e p r e s s u r e ) s t e a m d r u m s . A s s u c h t r i p l e p r e s s u r e H R S G s c o n s i s t o f t h r e e s e c t i o n s : a n L P ( o w p r e s s u r e ) s e c t i o n , a r e h e a t / I P ( i n t e r m e d i a t e p r e s s u r e ) s e c t i o n , a n d a n H P ( h i g h p r e s s u r e ) s e c t i o n . E a c h s e c t i o n h a s a s t e a m d r u m a n d a n e v a p o r a t o r s e c t i o n w h e r e w a t e r i s c o n v e r t e d t o s t e a m . T h i s s t e a m t h e n p a s s e s t h r o u g h s u p e r h e a t e r s t o r a i s e t h e t e m p e r a t u r e b e y o n d t h e o n e a t t h e s a t u r a t i o n p o i n t . P a c k a g e d H R S G s P a c k a g e d H R S G s a r e d e s i g n e d t o b e s h i p p e d a s a f u l l y a s s e m b l e d u n i t f r o m t h e f a c t o r y . T h e y c a n b e u s e d i n w a s t e h e a t o r t u r b i n e ( u s u a l l y u n d e r 2 0 M W ) a p p i c a t i o n s . T h e p a c k a g e d H R S G c a n h a v e a w a t e r - c o o l e d f u r n a c e , w h i c h a l l o w s f o r h i g h e r s u p p l e m e n t a l f i r i n g a n d b e t t e r o v e r a l l e f f i c i e n c y . V a r i a t i o n s S o m e H R S G s i n c l u d e s u p p l e m e n t a l , o r d u c t f i r i n g . T h e s e a d d i t i o n a l b u r n e r s p r o v i d e a d d i t i o n a e n e r g y t o t h e H R S G , w h i c h p r o d u c e s m o r e s t e a m a n d h e n c e i n c r e a s e s t h e o u t p u t o f t h e s t e a m t u r b i n e . G e n e r a l l y , d u c t f i r i n g p r o v i d e s e l e c t r i c a o u t p u t a t l o w e r c a p t a l c o s t . I t i s t h e r e f o r e o f t e n u t i l i z e d f o r p e a k i n g o p e r a t i o n s . H R S G s c a n a l s o h a v e d i v e r t e r v a l v e s t o r e g u l a t e i n t h e i n l e t f l o w i n t o t h e H R S G . T h i s a l l o w s t h e g a s t u r b i n e t o c o n t i n u e t o o p e r a t e w h e n t h e r e i s n o s t e a m d e m a n d o r i f t h e H R S G n e e d s t o b e t a k e n o f f l i n e .
description
this describes heat recovery
Transcript of Heat Recovery Steam Generator
Modular HRSG
Modular HRSG GA
Heat recovery steam generatorFrom Wikipedia, the free encyclopedia
A heat recovery steam generator or HRSG is an energy recovery heat exchanger thatrecovers heat from a hot gas stream. It produces steam that can be used in a process(cogeneration) or used to drive a steam turbine (combined cycle).
Contents1 HRSGs2 Packaged HRSGs3 Variations4 Once-through steam generators (OTSG)5 Applications6 Manufacturers7 Block diagram8 See also
HRSGsHRSGs consist of four major components: the economizer, evaporator, superheater andwater preheater. The different components are put together to meet the operatingrequirements of the unit. See the attached illustration of a Modular HRSG GeneralArrangement.
Modular HRSGs can be categorized by a number of ways such as direction of exhaust gasesflow or number of pressure levels. Based on the flow of exhaust gases, HRSGs arecategorized into vertical and horizontal types. In horizontal type HRSGs, exhaust gas flowshorizontally over vertical tubes whereas in vertical type HRSGs, exhaust gas flow verticallyover horizontal tubes. Based on pressure levels, HRSGs can be categorized into singlepressure and multi pressure. Single pressure HRSGs have only one steam drum and steam isgenerated at single pressure level whereas multi pressure HRSGs employ two (double pressure) or three (triple pressure) steam drums.As such triple pressure HRSGs consist of three sections: an LP (low pressure) section, a reheat/IP (intermediate pressure) section, andan HP (high pressure) section. Each section has a steam drum and an evaporator section where water is converted to steam. Thissteam then passes through superheaters to raise the temperature beyond the one at the saturation point.
Packaged HRSGsPackaged HRSGs are designed to be shipped as a fully assembled unit from the factory. They can be used in waste heat or turbine(usually under 20 MW) applications. The packaged HRSG can have a water-cooled furnace, which allows for higher supplementalfiring and better overall efficiency.
VariationsSome HRSGs include supplemental, or duct firing. These additional burners provide additional energy to the HRSG, which producesmore steam and hence increases the output of the steam turbine. Generally, duct firing provides electrical output at lower capital cost. Itis therefore often utilized for peaking operations.
HRSGs can also have diverter valves to regulate in the inlet flow into the HRSG. This allows the gas turbine to continue to operatewhen there is no steam demand or if the HRSG needs to be taken offline.
Packaged HRSG
Emissions controls may also be located in the HRSG. Some may contain a Selective Catalytic Reduction system to reduce nitrogenoxides (a large contributor to the formation of smog and acid rain) and/or a catalyst to remove carbon monoxide. The inclusion of anSCR dramatically affects the layout of the HRSG. NOx catalyst performs best in temperatures between 650 °F (340 °C) and 750 °F(400 °C). This usually means that the evaporator section of the HRSG will have to be split and the SCR placed in between the twosections. Some low temperature NOx catalysts have recently come to market that allows for the SCR to be placed between theEvaporator and Economizer sections (350 °F - 500 °F (175 °C - 260 °C)).
Once-through steam generators (OTSG)A specialized type of HRSG without boiler drums is the once-through steam generator. Inthis design, the inlet feedwater follows a continuous path without segmented sections foreconomizers, evaporators, and superheaters. This provides a high degree of flexibility as thesections are allowed to grow or contract based on the heat load being received from the gasturbine. The absence of drums allows for quick changes in steam production and fewervariables to control, and is ideal for cycling and base load operation.
ApplicationsHeat recovery can be used extensively in energy projects.In the energy-rich Persian Gulf region, the steam from the HRSG is used for desalination plants.Universities are ideal candidates for HRSG applications. They can use a gas turbine to produce high reliability electricity forcampus use. The HRSG can recover the heat from the gas turbine to produce steam/hot water for district heating or cooling.Large ocean vessels (e.g. Emma Maersk) make use of heat recovery
ManufacturersSTF S.p.A. ([1] (http://www.stf.it/))Harris Pye (http://www.harrispye.com/index.php?page=home_en)Alstom([2] (http://www.alstom.com/power/fossil/gas-power/heat-recovery-steam-generators/))Ansaldo Caldaie S.p.a. (http://www.ansaldoboiler.it/)BHI Co.([3] (http://www.bhi.co.kr))Express Integrated Technologies (EIT) ([4] (http://www.expresstechtulsa.com/))Vogt Power/Babcock Power([5] (http://www.babcockpower.com/products/heat-recovery-systems/vogt-power-international))IHI Corporation([6] (http://www.ihi.co.jp/en/index.html))CMI Energy ([7] (http://www.cmigroupe.com/))Victory Energy ([8] (http://www.victoryenergy.com))Nooter/Eriksen ([9] (http://www.ne.com))NEM ([10] (http://www.nem-group.com))Doosan Heavy Industries & Construction ([11] (http://www.doosanheavy.com/))BHEL3DCAD (I) PVT LTD ([12] (http://www.3dcad.co.in.com/))Thermax Ltd ([13] (http://thermaxindia.com/))Innovative Steam Technologies ([14] (http://www.otsg.com))Larsen & Toubro Ltd ([15] (http://www.larsentoubro.com))Hamon Deltak, Inc ([16] (http://www.deltak.com))Greshams Ltd ([17] (http://www.gel1947.com))RCR Tomlinson ([18] (http://www.rcrtom.com.au/%7C))Rentech Boiler Inc.AZARAB Industery Co.DESCON Engineering Limited (www.descon.com.pk)Retubeco, Inc.(http://www.retubeco.com/home.aspx)GREENS POWER EQUIPMENT INDIA PVT.LTD.(http://www.greenspower.co.uk)MAPNA Boiler
Block diagram of IGCC power plant, which utilizes the HRSG
Block diagram of HRSG in Combined Cycle
Block diagram
See also
BMW TurbosteamerHRSG Users (http://hrsgusers.org)
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