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Conf-8210125lJC66, UC66a throughUC66j

CONF-8210125--Suppl.DE83 009736

GEOTHERMAL PROGRESS ONITORSpecial Supplement

Proceedings of the Geothermal Program ReviewOctober 25-26, 1982Washington, D.C.

US. Department of EnergyAssistant Secretary tor 'Conservation and Renewable EnergyDivision of Geothermal and Hydropower TechnologiesWashington, D.C. 20585DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the United StatcsGovernment. Neith er the United States Government nor any agency thereof, nor any of theircmployccs. makes any warranty, express or implied, or assumes any lega l liability or mponsi-bility for the accura cy, completeness, or use fulna s of any information, apparatus , product, orprocws discloscd,or represents that its usc would not infringe privately owned rights. Refer-ence herein to an y sptcific commercial product, pnxxss, or service by trade name, trademark,manufacturer, or othemise docs not necessarily constitute or imply its endorsement, recom-mendation. or favoring by the United States Government or any agency thereof. The viewsand opinions of authors exprcsscd herein do not necessarily state or reflect those of theUnited Statcs Government or any agency thereof.

CONF-8210125-Suppl.-16


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APPENDIX 0 - Presentat ion 16Topic:

Speaker: Paul Linam (F lu or )

Heber 50 W e B i nar y C yc le P l an tHeat Cycle

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DISCLAIMER

This report was prepared as an account of work sponsored by anagency of the United States Government. Neither the United StatesGovernment nor any agency Thereof, nor any of their employees,makes any warranty, express or implied, or assumes any legalliability or responsibility for the accuracy, completeness, orusefulness of any information, apparatus, product, or processdisclosed, or represents that its use would not infringe privatelyowned rights. Reference herein to any specific commercial product,process, or service by trade name, trademark, manufacturer, orotherwise does not necessarily constitute or imply its endorsement,recommendation, or favoring by the United States Government or anyagency thereof. The views and opinions of authors expressed hereindo not necessarily state or reflect those of the United StatesGovernment or any agency thereof.


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December, 1982

Geothermal Binary CycleDemonstration Power Plant

Heber , Ca l i fo rn ia

I n t r o d u c t i o nThe Fluor Corporat ion i s engaged i n d e ta i l ed eng ine - r i ng o f t he Geo th -rmalB in ary Cycle Demonst rat ion Power P la nt which w i l l be b u i l t i n th e I m p er ia lVa l ley a t Heber, Ca l i f o r n i a . Th is p la n t i s sponsored by the Department o fEnergy t o prove commercial ope ra t ion o f the B inary Cyc le process f o r gener-a t i n g e l e c t r i c power from the thermal energy i n a geothermal b r ine .B ina r y C yc le D esc r ip t i onThe binary cycle process i s d e p ic t ed i n a b b r ev i at e d f or m i n F i g u r e 1.w o rk in g f l u i d o pe ra te s i n a c lo s e d c y c le . As a l i q u i d , i t s drawn f roma re se rv o i r and pumped to s up er cr i t i ca l p ressure .exchange w i t h t he b r in e t o a su pe rc r i t i c a l t empera tu re and l e t down i npressure th rough a tu rb ine wh ich dr i ve s an e le c t r ic a l genera tor . Vaporswhich exhaust f rom the tu rb ine are condensed and re turn to the l iqu idr e s e r v o i r t o c om ple te t h e c y c le .Working F lu id S e lec t i onE a r l ie r development work, conducted by F lu or i n 1978-1979, in ve st i ga te dmany facets o f process economics i nc lu d ing t he se lec t i on o f t he w ork ingf l u i d f o r t h e p ro ce ss c y c l e. T ab le 1 c on ta in s a l i s t o f t h e c a nd id atema te r ia l s conside red . More comp le te i n f o rma t ion on t he r es u l t s o f t hes tudy are conta ined i n EPR I Re po rt No. 1099, da te d June, 1979.t e r i a used f o r t h i s s e l e c t i o n p ro ce ss i n cl u de d i m p or ta n t f l u i d p r o p e rt i es ,such as :

TheIt s then heated by

The c r i -

o H ig h o v e r a l l e ne rg y c on v e rs i on e f f i c i e n c y f o r t h e c y c l e@ Low u n i t cos t0 R e a d il y a v a i l a b l e f o r makeup t o t h e p l a n t0 Compat ib le wi th carbon steel equipment and pip ing (Non-corrosive,o N o n - t o x i c f l u i d0 Non- tox ic products o f combustion (ie. , e l i e f f l a r e s t a ck em is sio ns )

e t c . )

Because hydrocarbons c ou ld bes t meet a l l o f the above c r i t e r i a , a numbero f al ternate hydrocarbon systems were invest igated next . O f the manyc o m n hydrocarbons, iso-butane was f o d t o be th e most p romis ing becausei t had:

o A t t r a c t i v e therm odynam ic p r o p e r t i e s w i t h r e l a t i v e l y lo w c r i t i c a lo Vapor pressure i n a des i rab le opera t ing range.

pressure and 1ow c r i i c a l temperature, and

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4.2 Exchanger F o u l i n g Factors (Continued)In addition .t o this, i t ,is ant ic ipa ted tha t the rec i rcu la t ingr k i n g f l u i d willa c i r c u l a t i ng r ige ran t stream. As a re su l t of thise maintained a t a clean lines s levelna lys is , the overa l l f o u l i n g fac tor for the Brine/H drocarbon heatxchanger was reduced,from 0.003 t o 0.0016 BTU/Hr F p F .

4.3 Materials ofThis s tudy po in t s up the the Brine/Hydrocarbon exchanger tubes. Over 1.5 m illio n li n ea l f e e t of t u b i n gi s used i n the design for this s ingle se rv ice . U n i t cost comparisonsf o r various tube designs are shown i n Table 5.Carbon st e el an ea Cure ,ma terials ar e ruled out because they don o t provide the cessary corrosion res ista nc e t o the br ine t o achievea 30-year l ife . U n i t cos ts for other potent ia l ly acceptable tubematerials pointed t o the se lec t ion o f AL29-4C a l loy s tee l mater ia l fort h i s s e r v i c e .A1 t hough th e AL29-4C material was no t code-approved when i t wasconsidered i n i t i a l l y for th is p ro je ct , app lica tio n has been submittedsubsequently t o th e ASME Code Committee for i t s approval.

4.4 Tube Wall ThicknessThe required wall thickness for the Brine/Hydrocarbon exchanger tubesi s e s tab l i shed by t he r e l a t i ve ly h i g h shell-side de'sign pressure ofthe hydrocarbon flu id . In it ia l s tr es s calculation s ' , based on there s i s tance to co l laps ing from the externa l pressure , indica ted theneed fo r 18 BWG tub es. Because th e su p p l y mill yas unable t o produceAL29-4C tubes w i t h walls thicker t h a n 20 BWG, the s t r e s s ca lcu la t ionswere reviewed. I t was then found t h a t w i t h the shear s t rength of th eAL29-4C mate r ia l , a 20 BWG tube wall thickne ss was indeed sa ti sf ac to ryf o r 30-year l i f e a t the d e s i g n c o n d i t i o n s .

4.5 Optimization of Exchanger Surface RequiredAn optim ization study was prepared which re la te d t he s iz e of theBrine/Hydrocarbon heat exchanger t o the br ine c i rcula t ion f low ra te .he results of this s tudy are re f lec ted i n the curves of Figure 5.he t o t a l of the capital and operating cost elements evaluated on anet worth basis shows a m i n im um value corresponding t o a hea t t ransfersurface area t o t a l i n g about 370,000 square fee t .4.6 Optimized Number of Shel ls in Ser iesThe original design fo r the Brine/Hydrocarbon exchanger called fortwo para l le l t ra i ns with three sh e l ls in ser ie s . Other reasonabledesigns which were invest igated as a1 ternates included four, s i x , ande igh t s he l l s i n s e r i e s . A lesser number of exchanger bundles were notconsidered because i t was f e l t t h a t the bundle diameters would becomeunacceptably large and less easy t o main ta in .

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4.7 Tube S u p p o r t Optimizat ion

supporting the tubes w i t h a network o f small diameter rods which extendf r o m wall t o wall across the inside of the shel l. Each successive setof rod supports is oriented w i t h a 90" r o t a t i o n from the previous set.

The results of the Bri ne/Hydrocarbon exchanger opt imiza t ion study aresummarized i n Table 6, which defines the changes made to the exchangerspecifications an d i n Figure 7, which reflects the relative costsavings due t o these changes.

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COOLlNOCONDENSER WATERXCHANQER

HYOROCARBONCIRCULATINQ PUMPS

mB I N A R Y C Y C L E P R O C E S S


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' A FIGURE 3BRINE/HYDROCARBON HEAT EXCHANGER

4 - P A S S SHELL DESIGN

2-PASS SHELL DESIGN

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Y

0I-oLL0ZA30LLI2

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LLWZU0m

FIGURE 4BRINE/HYDROCARBON HEAT EXCHANGER

.oo 16

.oo 10

.0006

a

BRINE FOULING FACTOR TEST RESULTS

\\EXCHANGER OPERATINGTEMPERATURE RANGE

" ,I I 8 I 1200 250 300 860lo 0 160

BRINE OPERATING TEMPERATURE (OF)

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300

FIGURE 5BRINE/HYDROCARBON HEAT EXCHANGER

EXCHANGER SURFACE OPTIMIZATION

00

1 .

POWER C O S T----------------400 600

SURFACE A R E A (10 F6


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h

Iu

zcK[x) rn 3 0n v I I I v z v 3 Crn - m rn-

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t 0am

P z- m 2 40P00> Pm 07 I > - X 0X > zG arn rn rn2c1 Q)rn


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FIGURE 7

B R I N E I H Y D R O C A R B O N H E A T E X C H A N G E RCOS T REDUCTION SUMMARY

RELATIVE COSTRELATIVE COST

REDUCED \

I OF

SHELL PASSES

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CANDIDATE W O R K I N G FLUID$CONSIDERED FOR BINARY CYCLE

WATERCARBON DIOXIDEAMMONIAHALOCARBONS (FREONS, ETC.1HYDROCARBONS

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TABLE 2CANDIDATE HYDROCARBON SYSTEMS,

CONSIDERED FOR BINARY CYCLE

WOBUTANE (100%)

- ISOBUTANE%) - ISOBUTANE (80ISOBUTANE (eo%)

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>

f

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TABLE 3

?

HEBER POWER GENERATING PLANTOPERATING PARAPETERSSTART OF RUN

(55OF WETBULB k I E N T TEMP)Plant Rating 70 W eBrine F l o w Rate 7.9s3x106 lb/hrHT Exchanger In le t 360 OFHT Exchanger Exit 160 OFReinjection Temp (Mfn) 150 OF

Hydrocarbon F l o w Rate - 8 . 3 4 ~ 1 0 ~b/hrHT Exchanger Exit Temp 305 OFTurbine I n l e t 305 OF

575 psiaTurbine E x i t 7 3 psiaCondenser Inlet Temp 159 OFCondenser Exi t Temp 101 OFc c-


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SAN DIEGO GAS AND ELECTRIC COMPANYGeothermal Binary DemonstrationPower PlantSDG&E Contract .I-023200

TABLE 4

FLUOR POWER SERVICES, INC.Irvine, CaliforniaFPS Project No. 832557

* , . ' , . BRINE/HYDROCARBON HEAT EXCHANGERFABRICATION COST COMPARISONNUMBER OF SHELL SIDE PASSES

RELATIVE COST RELATIVE COSTFABRICATION COST ELEMENTS

SHELLLONG BAFFLESTUBE SHEETS, CHANNELS, ETC.TUBESTUBE INSTALLATION

TOTALS

OF OF THE2-PASS SHELLS-PASS SHELL( X ) , ' (% )

14.7 15.410.2 3 . 715.1 14.545.2 45.2 -

14.8 14.8

100.0 93 . 6

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SAN DlEGO GAS AND ELECTRIC COMPANYGeothermal Binary Demonstration Power PlantSDG8iE Contract J-023200

TABLE 5W T EXCHANGER TUBING PRICES

FLUOR POWER SERVICES, INCIrvine, CaliforniaFPS Project No . 832557c,.

TubeMaterialCarbon Steel

A-210 Gr. CA-179A-214Alloys, Other

Titanium Gr. 2

Titanium Gr. 12

Sea Cure

AL29-4

AL29-4C

TubewallGauge (min.)'

121414

18201820182018201820

Unit Price (3/4" O.D. Tubes)$ /F T S/FT' (1)

0.900.790.314.584.021.58

3.17 16.152.293.732.76

11.6719.0014.06

1.57 8.001.13 5.762.68 13.651.96 9.98- Not Available -1.14 5.81

Note:(1 ) Basis i s for gross surface.Unit cost for net surface w i l l be sl ig ht ly greater.

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DIEGO GAS AND ELECTRIC COMPANYh/"othermal Binary Demonstration Power PlantSDG&E Contract 54 23 20 0 FLUOR POWER SERVICES, INCIrvine, CaliforniaFPS Project No. 832557TABIS 6

BRINE/HYDROCARBON HEAT EXCHANGERMECHANICAL DESIGN SPECIFICATIONS

L a t e s tn i t i a l2Tota l Sur face , F t 568,000 304,240

S h e l l sFluid HandledMetallurgyTo t a l Number

Hydrocarbon HydrocarbonCarbon S te e l Carbon St e el6 " 8

S h e l l Arrangement 2p x 3s 2p x 4 s(No. i n P a ra l le l x No. i n S e ri e s) 120" x 70' 80" x 66'

4 2iz e Ea . , I D x LengthShe l l PassesWeight Each, Lbs. 840,000 380,400Tubes

BrineRod Baff les3/4" x 18 BWG

Fluid HandledSupport DesignDiameter x Wall Gauge,Metallurgy AL 29-4

3/4" x 20 BWGNumber/Bundle

Fouling Factors BTU/Hr Ft2 OFShe l l S ideTube Side

Note:(1) NTIW = No Tubes i n Window design .

6896 3000

0.002 0.0010.001 0.0006

113_geothermal progress monitor

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