22.033 Process Heat

La ure n A yers Sara h La de rma n Adit i V erma

Anon ymous stude nt

Present ati on 1

Octobe r 5, 2 0 1 1

Outline

 Sys tem La yout

 Heat Exc ha ng er Design s

 Heat Stora ge Opti on s

 Heat T ran sport

 Fut ure W ork

System Layout

Core

65 0 C

76 0 C

Hydroge n Plant

Bu rn w a ste p ro d u ct to rai se temp era ture for hy dro ge n pl an t.

Provi de re a ctor w ith ex tra he at.

Heat Storage

24 0 C

T ypes of Heat Exc hangers Investigated

 Stan da rd shell an d t ub e

 Prin te d circuit he at excha ng ers

 Helical shel l a nd tu be

 Th erm osyph on s

Criteria for Sel ecting a Heat Exchanger

 Opera tin g tem pe ratu re an d p ressure

 High he at tran sfer pe rfo rma nce

 Ef fectiven ess

 Fou lin g

Courtesy of MERUS GmbH. Used with permission.

Multi ple Pass Shell an d T ube with Continuous Heli cal Baf fles

Photo from Q. Wang

Courtesy of Elsevier, Inc., http://www.sciencedirect.com . Used with permission.

Ma x. ope r a ting pr essur e: ~70 MP a

Ma x. oper a ting t emper a tur e : depend en t on m a t erials

Induc ed turb ulence + high shear s tr e 6

ss =

less f ouling

Printed Circ uit Heat Exc hangers ( PCHEs)

• All - me t al HXs made of dif fusion

bond ed pla t es

• Long desi gn li f e (u p t o 6 0 y ear s)

• Compact, mas s/d uty r a tio of 0.2

Dif fus ion bon d in g of PCH E p la t es ( Hea tr ic TM )

C r os s sec tional vie w of th e s em i - ci r cul a r p ass ag es ( Hea tric TM )

t ons/MW

• High oper a ting t em per a tur es (u p t o 90 0 C) and pr ess ur e (6 0 M Pa )

• Hi gh s urf ace ar ea densi ty ( 250 0

m 2 / m 3 )

• Hyb ri d fi n and pla t e typ e PCHE , H2X , suit able f or c oup li ng g aseous and l iquid w ork ing flui ds

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Cur r en t o p er a t in 7 g e x p erie n c e o f H ea t ric TM PCH Es

( Gezeli u s , K., “ D esig n o f Co m p act In te rm edi ate H eat Exc h an g ers fo r Gas Co o led Fa st React o rs, ” Bach elo rs’

& M aste rs’ Thesis, M IT, J u n e 2 0 0 4 .)

Heat Exchanger Requirements

 Ope rat in g T em pe rat ure s

 HX c on ne ct ed to CO2 lo op : 6 50 - 900 ºC

 Hyd ro ge n pl an t: 7 00 - 900 ºC

 Biofu el s pl an t: 240 - 300 ºC

 Heat s tor ag e: 30 0 - 500 ºC

 Sta nd ard ized he at excha ng er de sign will redu ce pla nt comp lexity an d o pe rati ng an d ma int en an ce costs

Heat Exchanger Configurations

 T wo HX in stead of singl e h igh te mp era ture HX to in crease de sign lif e

 Conn ect pro cess he at sy stem in pa rall el or series

 Remo ve he at from th e second ary cy cle be fore the po wer conversion sy stem

 Need to de ci de with c or e

 HX de cisions will dep en d on flo w rate s a nd tem pe ratu res pro vided by core an d n ee de d b y bi of ue ls an d hydro ge n pl an ts

Benefits of Heat S torage

 Pla te au e ne rgy flu ctua tio ns du rin g da ily cycles

 Providi ng lowe r te mp era ture to bio fue ls witho ut wasting he at

Heat Stora ge Options

 La te nt Hea t vs. S en sible Hea t

 La ten t – st or in g e ne rg y in c he mica l bo nd s

 Sens ib le – us in g c ha ng e of temp er atu re of mate ria l to stor e h eat (s pec ific hea t c apa cit y)

 Decide d on la ten t h ea t

 Can st or e hig he r en er gy de ns ity

 Prov id es he at at co ns tan t ope ra tin g temp er atu re

 Use s ph as e c ha ng e ma ter ia ls

Phase Change Material De cis ion T ree

Courtesy of Elsevier, Inc., http://www.sciencedirect.com . Used with permission.

PCM Selecti on

 Mu st ha ve me lti ng p oi nt in desire d op era tin g tem pe ratu re ran ge

 Ide al Chara cteristics:

 High la ten t hea t o f fusi on pe r u ni t ma ss

 High de ns ity

 High sp ec ifi c hea t

 High the rma l co nd uc tiv ity

 Chemi ca lly st ab le

 Non - co rro siv e to the co nta inmen t mate ria l

Liquid - Solid PCMs

 Para f fin s & Sal t Hy dra tes

 Oper ati ng temp er atu re too lo w

 Sal ts

 Lar ge ran ge of ope rat ing tempe rat ure s

 Is su es : co rr os io n & l ow the rma l c on du ct iv ity

 Me tal s

 Des ira bl e the rmo dy na mic pr op er tie s

 Is su es : fre ez in g c an c au se st re ss es to co nta in men t, temp er atu re ra ng e is limi ted

Salt and Metal PC Ms

Courtesy of Elsevier, Inc., http://www.sciencedirect.com . Used with permission.

Looki ng Ahead

 Cont ain me nt structure cann ot be de signe d u nti l a PCM is chosen

 Mater ial co mpati bil ity co nc ern s

 V olu me of ma teri al is de pe nd en t on :

 Ther mod yn amic pr op er tie s of the mat er ia l

 Amoun t of en er gy th at ne ed s to be s tor ed

Heat Transport Methods

 The rmosypho ns

 Use s gr av ity an d p ha se c ha ng es to mov e h ea t l on g di st an ce s with mi ni mal he at lo ss

 High ly de pe nd en t o n l oc ati on of pl an t

 Heat pip es

 Can us e cap ill ar y ac tio n a nd if in c or re ct or ie nta tio n, gra vit y can as sis t

 Can al so us e c en tri pe tal , e le ct ro ki ne tic , mag ne tic , an d o smo tic fo rc es

• No t as practica l for l on g di stance s an d no t a s we ll

deve lo ped technol ogi es 17

Heat Transport Decisi ons

 Me tho d of cond en sate tran sport de term ine d by dista nce be twee n pla nts

 Will mode l hy dro gen pl ant ex plo sio ns an d b iof uel pl an t fi re s to d ete rmin e sa fe dis tan ce s

 Ma teri al an d wo rking flu id de term ine d by HX choi ce an d te mp era tu re en viron me nt

Future W ork

 Fin ali ze he at exchan ge r an d h ea t storag e de signs

 Mo de l sys tem on ce ini tia l outp uts/in pu ts are avai la bl e

 Matl ab , EES , RELAP

 Heat sink as a safet y m ea sure at hydrog en pl an t

 Dete rmin e pla nt dista nces as mo re d ata be come s avail ab le

Questio ns?

MIT OpenCourseWare http://ocw.mit.edu

22.033 / 22.33 Nuclear Systems Design Project

Fa ll 2011

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