biomass fueled gt development

8/10/2019 Biomass Fueled GT Development

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BIOMASS

FUELED GAS TURBINE DEVELOPMENT

Joseph T. Hamrick

Aerospace Research Corporation

5454 Aerospace Road

Roanoke, Virginia 24014

Keywords: Biomass Fue l, Gas Tur bines , Power Ge ne rat ion

INTRODUCTION

Research and development

on

a

3000 kw

wood burning g as tu rb in e power gener ati ng

system has progressed t o t he product ion s tag e.

A

sys tem using a General Electr ic

a i r c r a f t d e r i v a t i v e g a s t u r b i n e

i s

be ing p repared fo r in s t a l la t i on a t Huddles ton,

Vir gin ia. The gen era ted power

w i l l

be so ld t o th e V ir gi ni a Power Company. The

R6D s y s t e m loca ted a t Red Boiling Springs, Tennessee,

w i l l

be upgraded f o r ooera-

t i on wi th t he Genera l E le c t r i c engine.

bagasse wi th good re s u l t s . Sorghum and sug ar cane promise

t o be major source s of

f u e l

in

t h e f u tu r e .

Sweet sorghum and su ga r cane ju ic es a r e re ad il v converted

t o a lcoho l by yeas t f e r -

mentation. S w e e t sorghum can be grown throughou t the Un i ted S ta te s as we l l a s the

tro pic and temperate zones of t he ear th . These p la n ts have t he h igh est conversions

of so la r energy i n t o biomass of any of th e spec ie s

in

the pl an t kingdom, substa nt-

i a l l y g rea te r than t r ees . With the u se o f bagasse

as

a

f u e l f o r ga s t u rb i n e s i n

the generation of power, i t

is

po ssi ble fo r t he income from power s al e s t o reduce

the cos t of e thy l a lcoho l w e l l below that

f o r gasoline. The sorghum gr ai n can be

used for fermentation or food.

from the turb i ne can be used t o concentrate th e ju ic e , make alcohol , d ry the

bagasse o r genera te s team fo r in je c t io n i n t o the tu rb ine .

t o concentrate the j u i ce and dry th e bagasse fo r vear -round use dur ing the harves t

per iod .

Growth of sugar cane and sorghum on the 66.4 m il l i on ac res of land taken out of

product ion i n the U.S. between 1981 and 1988 can suupl v enough energv t o gen er at e

34 percent of t he power th a t was generated i n 1986, enough to supply incr eas ed

power demands i n t o t he ne xt century.

A t

t h e c u r r en t

rates

paid by Virg i n ia

El ec tr ic Power Company f o r power generated w it h renewable fue ls , 25.4 b i l l i o n gal-

lons of a lc ohol can be produced from th e pr o f i t s earned on power sales, enough to

s up ply ga so ho l t o t h e e n t i r e n a t i o n .

The

s y s t e m ,

which can be located

a t

any ooint where there

i s

a

power distr ibution

l i n e and a sorghum or sugar cane source,

can provide jobs

in

the a r ea and an a l te r -

n a t i v e c r o p f o r f a rm e r s w h il e s a v in g b i l l i o n s of d o l l a r s on set-aside pavments.

A t

20/bar rel, approximately 8 b i l l i o n would be saved

on

the tr ade imbalance by

the r educ t ion of o i l import s .

Tests w e r e conducted with sug ar cane

The high volume, high temperature exhaust gases

There

i s

adequate heat

BACKGROUND

INFORMATION

Research on wood burning gas tu rb in es was s t a rt e d by Aerospace Research C orporation

i n 1978.

e r a t i n g s ys te m a t

a

f a c i l i t y l oc a te d

in

Red Boiling Springs, Tennessee.

m i ll io n d o l l a r s i n U.S. Department of Energy f unds and a matching amount of p ri va t e

funds

were

spent i n car ry in g out the program.

were

furnished by the

i r

Force and Naval

A i r

Systems Command.

A

view of the

research and development f a c i l i t y is shown in f igure 1.

t

culminated i n t he ope ration of an Allison T-56 gas tur bin e power gen-

Over two

In add i t io n , gas tu rb ine engines

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FI GURE

1

Vi ew Of Faci l i t y At Red Boi l i ng Spr i ngs, Tennessee

Oper at i onal di f f i cul t i es whi ch r esul t ed i n l ear ni ng cur ves pecul i ar t o t he system

such as wood pr ocessi ng, conveyi ng, dr yi ng, combust i on, ash r emoval , engi ne st art -

i ng, synchr oni zati on wi t h t he TVA power di st r i but i on gr i d. and devel opment of

emergency pr ocedures ar e covered

i n

r ef erence

l .

Feedi ng a pul ver i zed s ol i d i nt o

a hi gh pr essur e chamber and deal i ng wi t h t urbi ne bl ade f oul i ng pr esented t he gr eat -

est chal l enge.

A n

ant i ci pat ed pr obl emt hat was most f eared at t he outset , erodi ng

of t he turbi ne bl ades, never mat er i al i zed.

erosi on has been detect ed. The measures taken to r esol ve t he t wo pr obl ems and t he

appr oach t aken w t h t he General El ect r i c LM

1500

gas t ur bi ne i n meet i ng the pr ob-

l ems ar e pr esented.

Modem ai r cr af t engi nes whi ch requi r e ver y hi gh power t o wei ght r at i os are desi gned

f or hi gh turbi ne i nl et t emperat ur es and hi gh compr essor di schar ge pr essur es.

t ur bi ne bl ade cool i ng t echni ques, advanced mat er i al s,

and more sophi st i cated desi gn

met hods have become avai l abl e the pr essur e r at i os and al l owabl e t urbi ne i nl et t emp-

at ur es have i ncreased t o hi gh l evel s. As a r esul t , the modern ai r craf t der i vi at i ve

gas t ur bi nes ar e l ess sui t abl e f or operat i on wi t h bi omass t han t he ear l i er model s.

The cur r ent need f or l ow t ur bi ne i nl et

t emper at ure and l ow combust or pr essure wi t h

bi omass makes t he ear l i er model s mor e compat i bl e.

wel l i nt o the bi omass pi cture.

I n over

1500

hour s of oper ati on,

no

As

The

LEI

1500

gas t ur bi ne f i t s

THE ROTARY

AI R

LOCk FEEDER

The r ot ar y ai r l ock feeder i s al so r ef er r ed t o as a r ot ar y val ve.

of a r ot ar y f eeder i s shown

i n

f i gure

2.

A

schemat i c vi ew

Wms

OWPRESSURE EM

e ; . ' AI R VENT

OQ . 4

0

OO 1 . . . - -

, s o . * - -

*.

.:

.p * ,*t

e*, ,< ,

~ O 0

.

, .

6

c.

I

0

HIGH

PRESSURE END

FI GURE 2

Schemat i c Of A Rot ary

Air

Lock Feeder W t h Ei ght W per Vanes

*

A

l i st of r ef er ences i s I ncl uded a t t he end of t he paper .

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Refer r ing to f igu re

2,

t h e t i p s a nd s i d e s o f t h e v an es a r e f i t t e d w i th s e a l s t h a t

compartmental ize p ar t i c l es

fed i n t o a low press ure se ct or f o r movement around to a

zone of high pre ssu re and thenc e in to th e combustor. major e f f o r t was dir ec ted

toward development of long la s t i n g se al in g methods and ma te ri al s. Sawdust

is

an

extremely abras iv e ma ter ia l th at req uire s spe ci al techniques t ha t were developed

in

the program.

To meet t h e

130 psi g requirement of the RSD i n s t a l l a t i o n two a i r

lock f eeder s o pera t ing in se r i es p roved adequa te .

To provide cons ervati ve design

margins,

i t is

planned to use two feeders i n series f o r t h e

90

ps ig p ressu re r e-

quirements of t he Huddles ton in s t a l la t i on

as w e l l

a s

in s uc ce ed in g i n s t a l l a t i o n s

up t o 6000

kw.

TURBINE

BLADE FOULING

A t the ou ts et of t h e RSD program re po rt s on work involved with s o l i d s fuel ed gas

tur bin e systems (References 2 through

5

were rev iewed a t length .

problem with coal f i red

tu r b in e s was eros ion of t he turb ine blades .

A

secondary

problem was fou l in g of the b lades .

Research Laboratory a t Leatherhead, England (Ref. 2 ) i t was determined that single

cyclones i n se r i e s adequatel y cleaned th e ash from th e combustion gases t o prevent

eros ion . Therefore ,

i t

was decided t o use only s in gl e cyclones i n t h e wood burning

program.

As

a r e s u l t ,

ther e has been no eros ion of the turb ine b lad es i n the more

tha n 1500 hours of op er at io n with t he gas tur bi ne s used i n the R6D program. In the

R6D performed by t h e Au st ra li an s

(Ref. 3) on brown c o a l

i t

was found necessary t o

l i m i t

t h e t u r b in e i n l e t t em pe ra tu re

to

12000F t o avoid dep osi tio n of ash on the

tu rb ine b lades.

the re was no s ig n i f i ca n t deposi t ion at14500F af t e r 1000 hours of operat ion with

black coal . I n te s t s with p ine sawdust i n ea r ly operat ion a t Roanoke with

a

small

Garrett

tu rb i ne no s i gn if ic an t deposi t ion occurred a t 1450F in

2

hours of oper-

a t i o n .

necessary to per iod ica l ly c lean the turb i ne b lades with mil led walnut hu l ls when

f i r i n g w it h

a

mixtur e of oak and poplar sawdust a t 14500F tur bin e i n l e t temperature.

Above 1450F th e pa r t i c l e s adhered t o th e bla de s and could be removed only by

scraping .

LM 1500 gas turb ine i n the Huddles ton in s t a l la t i on

is

well below any problem zone

for deposi t ion with sawdust .

The primary

In work performed by the Coal Ut il iz at io n

I n t h e RSD performed a t Leatherhead, England with s ta ti on er y blades

I n t e s t s wi th the Al lis on T-56 a t Red Boilin g Springs i t was found

The 1248'F tu rb in e in l e t temperature needed t o produce 4000 kw with the

DISCUSSION OF LM 1500

GAS TURBINE

PERFORMANCE

AND

FACTORS FAVORING

I T S

SELECTION

When the advancement w a s made from th e Ga rr et t 375 kw gas turb ine to a larger eng-

in e , the All iso n T-56-9 gas turb ine s el ec ti on was made on th e basi s of

i t s

perceived

easy ada pta b i l i ty t o th e system and the ava i l ab i l i t y of used engines f rom the

U.S.

A i r Force. A s t h e RSD program advanced, i t became c l ea r tha t the tu rb i ne in le t

temperature would have

to be r e s t r ic te d to 14500F t o avoid excess ive tu rb ine b lade

foul ing .

o v e r a l l e l e c t r i c a l o u tp ut o f

2332

kw.

With a 1450F tur bin e i n l e t temperature the

output drops t o 1500 kw, a value too low fo r economical op eratio n.

A

search fo r a more su i ta b le gas tu rb ine f rom s tandpo in ts of av a i la b i l i t y , adapta-

b i l i t y to wood fue l i ng , and e l ec t r ic a l ou tput l ed t o se lec t ion of the Genera l

E l e c t r i c 5-79 gas ge ne ra to r and companion power t ur bi ne .

a to r and power tu rb in e was given the designa tion

LM

1500 by General El ec tr ic .

a i r c r a f t p ropu ls ion th e ho t gases leave the eng ine

a t

h igh ve loc i ty , p rope l l ing

the a i rp l ane forward.

power turbine.

f a v o r a b l e f e a tu r e of a two shaft arrangement, such as this one,

is

t h a t t h e g a s g e n e r a to r c an op e r a t e e f f i c i e n t l y a t p a r t l o a d by a d ju s t i n g i t s

speed downward while th e power t urb ine opera tes a t t he require d c onstant speed fo r

The tu rb in e i n l e t tempe rature of th e T-56-9 i s 1700F a t i t s normal rated

The combined gas gener-

For

For use i n power production t he hot gases

are

ducted t o a

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power gener at i on. The compr essor ef f i ci ency i s hi gh over a broad range. Thi s

s

made possi bl e by adj ust ment of var i abl e st at or s i n t he f i r st si x stages of t he

compressor.

f l ow, r ot at i ng st al l i s avoi ded and good compr essor ef f i ci ency i s mai nt ai ned.

Rotat i ng st al l i s a phenomenon associ ated wi t h f l ow separ at i on on the compressor

bl ades as t he angl e of at t ack on t he bl ades i ncreases wi t h changes i n r otat i ve

speed and ai r f l ow

i cal operat i on over a w de range of power pr oduct i on. Det ai l ed i nf ormat i on on

t ur bi ne i nl et t emper at ur e,

compressor di schar ge pressure, and wood f eed rat e as a

f unct i on of power out put was der i ved f r om General El ect r i c speci f i cat i on M D- S-

1500-2.

Tur bi ne I nl et Temperat ur e

By adj ustment of t he st at or s t o match t he compressor speed and ai r

Compr essor ef f i ci ency over t he speed r ange r esul t s i n econom

Fi gur e shows a st r ai ght l i ne r el at i onshi p bet ween

FI GURE Pl ot Of Tur bi ne I nl et Temper at ure Versus Generat or

Output W t h The G. E. LM 1500 GAS TURBI NE At

1000

f t .

Al t i t ude And Compr essor I nl et Ai r At

700F

t ur bi ne i nl et t emper at ur e and gener at or out put . Thi s char act er i st i c pr ovi des a

si gni f i cant amount of l at i t ude i n oper at i on w t h unt r i ed speci es of pl ant s or

sour ces of f uel s such as cl ean wast e. For exampl e, i t can be saf el y pr edi ct ed t hat

i n t he wor st

case the t ur bi ne i nl et t emper at ur e of 1200OF requi r ed

for a 34 kw

out put wi l l not r esul t i n excessi ve or di f f i cul t t o cl ean accumul at i ons on t he

t ur bi ne bl ades.

W t h nost wood speci es a

7000

kw out put pr obabl y can be tol er at ed.

Compressor Di scharge Pressur e - Fi gur e

4

shows a st r ai ght l i ne rel at i onshi p bet ween

compressor di schar ge pressure and generator out put . The pr i mary concer n wi t h pr es-

sur e i s t he f eedi ng of sol i d f uel i nt o the combust i on chamber .

maxi mum sust ai ned pr essure i n t he RLD

systemi s 130 pounds per square i nch.

Thus,

t he abi l i t y t o sust ai n f eedi ng of sawdust f r om3000 kw to approxi matel y

7500

kw

i s

assured.

f aci l i t y now bei ng prepared for i nst al l at i on at Huddl est on, Vi r gi ni a I s onl y 90

psi g.

M ni num per f ormance guar ant ees woul d be warr ant ed i n such cases.

The demonst r at ed

The

pr essur e requi r ed to pr oduce t he

4

kw pr oj ect ed f or t he pr oduct i on

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GENERATOR OUTPUT, KW

FI GURE 4

Pl ot Of Compressor Di scharge Pr essur e Versus Generat or

Output W t h The

GE.

LM

1500

GAS TURBI NE At

1000

f t .

Al t i t ude And Compressor I nl et Ai r At 70F

Wood Feed Rat e

-

The wood f eed r at e In f i gure 5 i s based upon a heat val ue of

8 200

Bt u/ l b f or sawdust . The heat val ue r anges f r om8100 Bt u per pound for oak to

8 600

Bt u per pound f or yel l ow pi ne.

Gr een sawdust as del i ver ed f r om t he

m i l l

aver ages

d

B

PI

Y

z

B

W

n

c

?3

n

w

F9

N U ~

s z

GENERATOR OUTPUT. Kh

FIGURE 5

Pl ot Of hood Feed Versus Generat or Output Wt h

GE.

LM 15

GAS TURBI NE At

1000

f t . Al t i tude

And Compressor I nl et Ai r At 70F

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approxlmately 45 percent

w a t e r

con ten t. Tr a i le r s 40 f t . long no rmally de l i ve r on

th e orde r of 25 tons of green sawdust pe r load. For th e 4000

kw

ou tpu t p ro jec ted

f o r t h e Hu dd le ston f a c i l i t y f i v e

t r a i l e r

loads per day w i l l be r equ i red . She l te r

fo r app rox imate ly f i f ty t ruck loads w i l l be needed t o assure continued operat io n

i n

th e win ter months when sawdust del iv ery can be e r r a t i c due t o weather condit ions .

ENGINE DURABILITY

ques t ion f r equen t ly a r i ses as t o t h e l i f e of a n a i r c r a f t d e r i v a t i v e g as t u r b i n e

i n st at io na ry power app lic ati ons. The answer

i s

t h a t t he lower power out put and

lower tu rb ine i n l e t t emperatu re t ha t

are

p r o j ec t e d f o r t h i s a p p l i c a t i o n make f o r

very f avo rab le longev ity f o r th e

LM

1500 gas tur bine .

before overhaul i s pred ic tab le . The gas genera to r i n the s ta t iona ry app l ica t ion is

never exposed t o th e extreme power requirements and high tu rb in e in l e t t empe rature s

th a t e x i s t d u rin g a i r p l a n e t a k e o f f .

i n s t a t i o n a r y a p p l i c a t i o ns

i s

adequate

f i l t r a t i o n of t h e

a i r

ent eri ng t he compressor.

A

tw el ve y ea r l i f e o r g r e a t e r

The pr imary requirement f o r long engine l i f e

SUGAR CANE

ND

SWEET SORGHUM FUELS

Sweet sorghum which

i s

highly drouth re s is t a n t can supply two to thr ee t imes

as

much fi be r energy per acr e as t r ee s i n some a rea s i n add i t ion t o the sugar produced

fo r a lcoho l and g ra in fo r food.

can be grown,

i s

even higherthan from sweet sorghum.

t h e r e

i s

no s t igma at tac hed t o i t s use

as

a f u e l , as t h e r e i s with

trees

renewable fuel

w i l l

r e su l t i n a ze ro ne t inc rease i n carbon d iox ide. Based on the

published resea rch re s u l t s (Reference 6) fo r sweet sorghum, th e 66.66 mi ll io n ac re s

taken ou t of production between 1981 and 1988 can supply t he ene rgy to ge ne ra te 34

percent

of

th e power generated i n 1986 i n th e U.S. The annual payment fo r se t t i n g

land as ide

i s

es t imated to be over

5

bi ll io n. Much more ad di ti on al acrea ge can be

ea s i ly devoted to sorghum as an a l t e r na t i ve crop . Besides p rov id ing fu e l fo r e lec -

t r i c power th e grain and sugar can produce i n excess of 25.4 b i l l io n gal lons of

e thano l which equa ls f i f t ee n percen t

of

th e energy supplied f rom imported o i l .

In tens i ve c u l t iva t i on of sugar cane and sorghum i n s t a t e s border ing th e Gulf o f

Mexico can r es u l t i n t r ip l i ng these ou tputs .

The y i el d f rom sugar cane, i n the are as where

it

A

further advantage

i s

t h a t

This

SUMMARY

The General Electr ic LM 1500 ga s tu rb ine has been chosen fo r us e i n t he wood burn-

ing power production system because o f

i t s

highly compatible performance character-

i s t i c s , t h e e a s e w i th which

i t

can be mechanically adapted t o th e system,

and i t s

r ea dy a v a i l a b i l i t y . S a l i e nt p o in ts a r e as follows:

1

The

4 kw

power output pro jec ted fo r t he product ion sys tem being readi ed fo r

i n s t a l l a t i o n a t Huddleston, Vir gin ia can be achieved wit h a 12500F turb ine in le t

temperature and compressor disch arge pres sure a t

90 ps ig . Both

are w e l l

below the

1450F tu rbin e i n l e t temperature and 130 psig compressor disch arge pr ess ure found

a c c ep t a bl e i n t h e R D program.

2.

below th e 145O0F tu rbi ne i n l e t tem perature and 130 ps ig compressor di sch arg e pre s-

su re found acc ep ta bl e i n t he R6D program.

3.

engine to th e ex t ern al burner required f o r wood and o t he r biomass fu els .

4.

power turbines

are

a v a i l a b l e

from manufacturers. In addit ion , a limited number

of

Power out put s up t o

7500

kw can be achieved with oak sawdust while remaining

There i s adequate d i s tance between t he compressor and tur b in e t o adapt the

5-79 gas gene rat ors ar e re ad il y ava il ab le on the overhaul and used market.

New

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servi ceabl e compl et e LM 1500 set s ar e avai l abl e f or i mmedi ate use.

5.

Bot h t he Red Boi l i ng Spr i ngs and Huddl est on f aci l i t i es are i deal l y l ocat ed f or

demonst r at i on of combi ned el ect r i cal power and

f uel al cohol pr oduct i on f r omsweet

sorghum

REFERENCES

1.

2.

3.

4.

5.

6.

Ham i ck,

J . T. , Devel opment

Of

Bi omass As An Al t ernat i ve Fuel For Gas Turbi nes,

Report PNL- 7673, UC- 245 Apri l 1991

Washi ngt on.

Rober t s, A. G , Barker, S. N. , Phi l l i ps, R. N et al , Fl ui di sed Bed Combust i on.

NCB Coal Ut i l i sat i on Resear ch Laborat ory Fi nal Repor t , U S. Depar t ment of

Ener gy Repor t FE-3121-15(a) , 1980. Nati onal Techni cal I nf ormat i on Servi ce,

Spr i ngf i el d, Vi rgi ni a.

F. L. McCay, Chai r man, The Coal - Bur ni ng Gas Tur bi ne Pr oj ect , I SBN 0642001499,

1973.

Summar y of The CPU- 400 Devel opment , Staf f , Combust i on Power Company, I nc. , U. S.

Envi r onment al Prot ect i on Agency Repor t on Cont r act s 68- 03- 0054 and 68- 03- 0143,

Oct ober 1977. Nat i onal Techni cal I nf or mat i on Ser vi ce, Spr i ngf i el d, Vi rgi ni a.

Yel l ot , J . I . et al , Devel opment of Pressur i zi ng, Combust i on, and Ash Separ at i on

Equi pment For a Di r ect - Fi r ed Coal - Burni ng Gas Tur bi ne Locomot i ve, ASME Paper

54- A- 201, 1954. Amer i can Soci et y of Mechani cal Engi neer s, Washi ngt on, D C.

DOE, Paci f i c Nor t hwest Labor at or y, Ri chl and,

Aust r al i an Gover nment Publ i shi ng Ser vi ce, Canberr a, NSW Aust r al i a.

J ackson, DR., Ar t hur , M F. et al , Devel opment

of

Sweet Sor ghumAs

An

Energy

Cr op, Report BM - 2054 Vol. 1 May,

1980.

Bat t el l e Col umbus, Col umbus,

Ohi o.

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biomass fueled gt development

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