Good Plans Gasifier

7/31/2019 Good Plans Gasifier

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MISSOURIWOOD GAS1FlERMissouri Department of NaturalResourcesDivision of EnergyP.O.Bo 176JeffersonCity, MO6510 ()751-4000

Sawmills - Farms - Industry


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- - &Fi rs t Pr in t ing December , I981 Revised January, 1983

ACKNOWLEDGEMENTS

This manual was assembled by Norman Lenhardt o f t he Mi sso ur i Departmentof Na tur a l Resources wi t h th e ass i s ta nce of Don Varney and Rose Ca r te r o fthe Ag r i cu l t u r a l Sec t i on , Depar tmen t of Na tu r a l Resour ces, D i v i s i o n o fEnergy. The t y p i ng and se c r e t a r i a l s k i l l s o f Donna Leppe r and Donna D ickne i r eand th e math convers ions ( i n th e appendix) by Dale Schafersman are g re at lyapprecr ated.

Grant Fundin=This manual was made pos s i b l e by a gra nt f ro m th e Department o f N atu ra l ResourcD iv i s i o n of Ene rgy t o t he Mon i teau County R #I S ch oo ls o f C a l i f o r n i a , M i s s o u r i .

Systems Oesion & C o n s t r u c t i o nPatent Pending by R & R Wood Produc ts, Cal i f o r n i a , Mis sour i

Th is sawm i l l g a s i f i e r was des igned and cons t ruc t ed by Raymond R is s l e r ofCa l i f o rn ia , Mi sso ur i . He has g r ac io us ly agreed t o share h is knowledge andd es ig n w i t h u s f o r p u b l i c d f s t r i b u t i o n .

Cover phot o from "Gen Gas t h e Swedish Experim ent frcm 1939 t o 1945".To ob ta in the Eng l i sh t r an s l a t i o n o f t h i s book, you w i l l need t oord er f rom U . S o Department of Commerce Na tio nal Tec hnic al In fo rm at io nServ ice; 5285 P or t Royal Road; Sp r in gf ie ld , VA 22161. P r ic e was524.00 as o f A p r i 1 , 1981.


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WOOD GASIFICATION WORKSHOP

We ha ve h e l d s e v e r a l a l l d ay w orkshop s i n J e ff er so n C i t y e x p l a i n i n g t h e f i n e rde ta i l s , p roblem s and suggested so lu t i on s abou t t h i s t ype of wood g a s i f i e r .

We hope t o be a b l e t o h o l d a few o f t h e se s e ss io n s a t o t h e r l o c a t i o n s a ro un dt h e s t a t e . Because o f bu dg et r e s t r i c t i o n s , t h i s wi-11 o n l y be p o s s i b l e , i fsome sponsoring group w i l l genera te the aud ience and prov ide a meet ing room.Our pas t workshop re g i s t r a t io n fee has been $20.00 p e r p e rs on t o c o v e r t h emeeting room, mai 1i g expense and th e dem ons t ra t i on u n i t and t ech n i c i ansspeaking fees.I f y o u w o uld b e i n t e r e s t e d i n a t t e n d i n g one o f t he s e wo rksho ps, p l e a s e w r i t et o us, and we w i l l n o t i f y y ou o f t h e p l a c e a n d' d at e o f o u r n e x t workshop.I f y o u wo ul d be i n t e r e s t e d i n sp o ns o ri ng o ne o f t h e s e m e et in gs , p l e a s e l e tus know t h e l o c a t i o n and t h e d a te ; h o p e f u l l y we ca n a v o i d c o n f l i c t s i nschedul i g .

CONTACT: Norman LenhardtB iomass Spec ia l i s tM is sou r i Depar tment o f N atura l ResourcesD i v i s i o n o f EnergyP.O. Box 176J e f f e r s o n C i t y , MO 65102


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Increase Woodland Products ThroughTimber Stand ImprovementJohn SIushw and J . IM. NicboIs. School of Fartry. Fishcna & Wildlife;Eldon L. Hf in , i\lissom Dtpmmmr of Consmacaon: a n d Ivan L. Sander. U.S. Fwur Smvice

What Is Timber Stand Improvement?Tim ber Srand Im provement ( 'ISI) denotes managem entpracrices chat improve the v~gor,product iv i ty , and qudi tyof stands of trea.In Mlssourt. :loung tree stands have become establishedreadily io l l ow ~ng urr lng or f ire . But , t m qu al i ty , speciescomposlrlon. and individual cm form am often undesirable.Further reduction in quality comes when the better t r m archarvared leaving the bad ones, and when fire scarred rrusrem an . The Jverage M~ssouriwoodland concalns abo ut 20 per-

cent cul l r m s and produces a t less than one-r hrd IU p t e n t l d .Using Timber Stand Improvem ent

,Many options are open to a woodland owner. He may wa TSI program cc increase the woodland's value for timberp rd uc n . wa te r , r ec re at ion , fo rage , wi ld li fe , na tura l h u t y , o rfor speed products . Fortunately, work done to improve oneuse also benefits others in most cam.

Various practices uxd a nd t m pecies d e c t e d s ho uld f i tthe chosen e m ph as~ s or the woodland. The n u m be r of t m sro keep depends on species, rype of s i te , management gods ,and size of the trees. Professional f o m t e n are available tohelp de te rm ~n e woodland 's porent tals and l i r n~ at io ns ndto help develop u l d carry out a suitable management plan.T yp es o i c m s ~ ~ s u a l l yemoved are: -

I . Cull trees and wide spreading "wolf' trees.2 . Trees inferlor because of their species.3 . Trees in terfer~n g w ~ t h he grow th and development

of selected desirable t m s .i. Damaged r r e s (broken off. bent over, fire na r re d ,seriouslv barked, etc., bur npecred to live at least onecurtlng cycle,.5 . Seriously d i d rees or trees serving as a b m d ~ n gground for unde s~rable nsects .

I r is Important: to remove or lull thew rypes of trees assoon as possib le irer an area has been logged to properly re-lease younger trees. Variety is i m p r a n t in a woodlandenvironment so chose rrees necessary for den trees, aesthetics.or special foods should be selected and reancd in the srandw h e n b e g ~ n n ~ n gprogram of TSI.The following pcacrices are among those uxd in TimberSrand Improvemen::S i r e Pnparatron fi r .\;arural R e p r o d v n ~ am Undrr~tocked tan d- -preparing the slte :o allow natural se dl ng or resprouting o idesirable species. or underplanrlng xe dii ng stock co id lv uxthe avaiiabie yrowlng space. T h ~ s racnce is used in poorly

Flgunl. Ellminrte your O o t r e r They stealpiantfood, moistureand space from your drlrrble trnr.stocked stands to fill large openings and i n c r c a ~cand denslry ,or to improve the species composirion.Thinning--curring t m s from an Im mature srand to increaserate of growch and improve form of the em ai m ng r m s.Prop er space varies depen ding on species, purpose of manage-me n t , and site qualiry. Table 1gives a range of spacing for treesof various diameters:Rrlwr-removing or killing undesirable older overtoppingt r m to encourage fast growch and better quality of vigorousyoung desirable trees.Pruning-removing lower limbs, to produce h e maximumclar lumber or veneer in rhe bum log. Prune only selectedhardwood trees where high-value species are grown on goods ius . This is recommended primarily in managing black wal-nu t .

In pruning lower Limbs of young trees, don't remove coomuch of the food produc ~ ng eaf s u h c e of the t ru . A t l ea stone half of rhe living crown of rhc tree should be left intact.Generally trees should be pruned b e hey reach 8 inches.i n d ia m et er . ~ i m b so be removed should be pruned berorethey reach 2 inches in diameter to reduce the wound s~ze.insunng proper healing, and co lessen rhe danger of entry bv

Table 1Tree Spocing Tree SpdclngDiameter (in. ) Range (tr.) Diameter ( ~ n . ) Range ctt.)

7- -1.6- 6.5 9 14.5- 18.-3 6.1- 8. 2 10 156-20.44 ' - 9.9 I 1 1- 0-22.15 9 0-11.6 I2 18. 1-25.86 10,3-13. -1 I3 !9.4-25.6

11.6- 15.0 14 20.3-27.28 15.0-lY.O 15 2 1.9-290Grcarn species or management purposes mav rcqurre other spclngs.Ln dnv th lnn ~n p he rallcst iieslrable r m s am usuallv hvorcd.Source: Even-Aped S ll v lc ul ~ rc or Upiand Central Hardwoods - -USDA Agriculrure Handbook i 55


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V1nr Rmrrc,al--On some area v i o a do cornid& Jamageto t rees . Vi na nor r e a r n d k a w c oiwtldlifr food due. rillcolor. erc.. should k kdled at chr m e ime orher s c u d im-provement w ork is done. Remove them by cutt ing &an u owco r k ground as possible and i m d i l t c l y t ta rc ir d t h e s tu m pwlrh an herbictde.Special Problemof Sprout Selection in TSI

Many h li ua ur i t u r d 4 s pecies sprou r havi ly &atire or cutting. Sprouts grow rapidly and o h onn m d t i p l c -s temmed c lump. Use r k uiddines for deciding how tohandle sprout c lump.1. Smiling 5prwts. originacing From severed seedlings,am as good as seedlings if the clumps are c h i d m reducecrown competition d o avoid bd snrm p conditions fromcimeiop~ngu he b w when the t m s become o lda .2. Trcc4nunp sprouts are less d s im b le rlmn d l i n gsproucr bur,may dev ciop Inn, good q d i r g % e m . d ep en din g o nrhe sue o i the s tump and the ong in pornr of c k prout. .Many

h r d d prouts d ea y rhrougn rhe large wound I& u hebiLV o i J sprout when pucnr s w a p r oes away.Sprout stands are b e r managed b a r n they reach 20 y c ~ ro t age. b r i v r ma ne nt pe rmi ts b e r r a s e lmr on o t tr ees fromrh c scmdpoin t o f amc hme nt to and size of thk prrru srwnp.~ n d m c l v ICUCN the danger of decay from wounds left Incua tng ~mmpanion p lwo.The best r r ea t o l a v e c om e fro m see dlin gs . d i n gsprouts. or sprout clumps arising from snrrnp i nches orLa5 in diameter. Spr ouo from lu gcr s t u m p may be sdectedit' rhcy an x very low on the stump and if rhe p u m t s tumpwound IS small.l i early tr c runcnr is made in a young s d t will entermatunr) . wt th the cr op r m p n m u t i y s ~ n g i estemmed.Where them hy k n o early tramrent. pole s d s f sproutortgln uc likely ro consist of sprout gnwpr. Afrer companions pro uts. ; o l d at th e bw with a V-shaped crorch. have grownm e m i ~ n c kn diameter. it is u r d y d f i c u l t to f ~ m ~ v eone wtrhour lavtng 3 large wound at the base of rhe other.thmuyh which d e c q w11l d d o p . T win s ol this rype s h l d!x let lone. Where r k p u o have a low U-rho* crotchh e m hem. hovner . or arc encireiy w e d rom eachother &we sround. one or more a n bed kc ig. 2 ) .TSI Cost Sharing & Technical Assistance

C a r sha rtng pnc r ica are avviable for TSI. For furtherinmrmactnn conucr your Emnr lon C m m . . \ l h o u ~Deprr-mcnt ot Consen.anon D u m c r F o m m . o r C o u a p A g n c u l d> a b t i ~ u t ~ o nonsewat ton Se w r e O6 ce .Free tcchntui +ursunce on d l t imber management pr rc-rircs I S ~ r u i h l ehrough locd Dunlc r For esc mo i r k .L [uraur iD c p m m e n r or C o w w a r i o n .

Methods of Removing Treesfrom CompetitionThe lvlaowner should keep tn mtnd :hat rn many c l r a

A p r o p r l r c o n d u c d r i m k r w l e (I mp ro vc mc nc h a w a t ) c m~ c o m p l t s h p r a r m o u n t or' TSI. Undesirable r m s not

flguro 2. From USDA. "timber Stand Improvement Intho Sodmm App.lwkl8n Region," No. 6OJ.r n e r c h o b l e m y be mnovcd by curting, dozing, brush-hogging. girdling. or by chr mic l l coo td . Chmicz l ly mar-in g large r r m ts more c c o n o m d r I m n f d l i n g and is momcemin to lul l them than u girdling. W h t ~ontrol of re-spr wr ing u d a r e d . c h e m i d s are morr &kcrive.Silvicides an d herbicides are chemicals wh ~c hct in x v dwoyr: As tnnrlocarion pouons, p h t hormones or p w r hregu&oo. conoct poisons. or soil smil mes . Some of the morecommon her b ic ~d ased in TSI oprrci onr are 2 .4 -0 . Amirroleand A m m u e .AN t h a d WR iwjm r r r u i r k t o . mps or orrumaulpkur if wd n g ~ kid irumrriou.. b y are voluiie and c h u r nponsnd s p n v d n f t w t ll dam-age d e s ir r bk p l m u , e p e c d l y o n wi nd y drys.Silvicrda a d M i c i d e a cm k applicd u ollow:I. Pr il l img m ') (.r&ukd in je r t io n- cu n are madet h u g h t k back and i ~ ,he grow ing cissue of che free com-p l d y around cfw t m . Uadiluccd 2.4-D m i n e is thenappiied ro the cw ntil h e chaniEli s r rm to t low fromthe cut. M a b e d injecton an be purchurd or rentedw k h -ply cfrc c h i d at the r ime thrp ma& rhe cut.2. S tn ap t m m n e n t - o f trea t h t have ken cur. Thestu mp should be thoroughly wet w ith c h c m d c Y r i e r m u n u eimmcdhcdv f d lowing cunlng.3. B d pqamg- may k xd efktively on trees leuthan 4 Inches in di un em . Sprry ckrnicai-oi l mi xn ut on lower12 t r ~ h e s i t he trunk wecrrng :he bark rhoroughlv.

For d e a l s h u t c he mic li m t x nr m. r c ~u k t io c u .maprccaucions on rhae mernob see UbfC Gurac +d6S. 'Yd.vP f ~ n r onnnl.

8 l ~ s ~ e an funnuan ceof Coooentlve Extoneon W ork Acrr ot M a y 8 and [email protected] oooorat~onw ~tn n e u n ~ m la tmsOe~anmmt;t A g r ~ c ~ f t u r e .eonara C.O ougrar. Oi re eo r. C o o o r n t ~ v e u n s t o n S ~ N I C ~ .ntvmtty of Miuoun and bncoln Unlvmity. Corumola.Ularoun 6521 1 8 An equal opponunlty rnmtutlon.

5 150 R r r i m r d and R e p ' n t e d J I8 L 3rW


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MISSOURI G E N GAS

The design a n d co ns tru cti on of t h i s sawmill wood g a s i f i e r was made poss ibl eby a g r a n t from the Missouri Department of Natural Resources, Division ofEnergy to the Reorganized School District # I of Moniteau County (California, MO ) .

The Department of Natural Resources - Energy Division issued this grant becauseof the energy, the money and the jobs that can be utilized by the future usesof wood gasification.

According to figures from page 34 of a 1978 publication by the MissouriDepartment of Co nserv ation, Fo rest ry S ec tio n, e n t i t l e d Wood Residues inMissouri ; there are 847.22 mil l ion (mm) pounds of unused equivalent ovendry pounds of sawdust and shavings produced annually in Missouri. This convertsto 1,236,286 barrels of No. 2 fuel oi l or about 1% of Missouri ' s average annualo i l a n d gas01 ine consumption. This a ls o conv erts t o $37,088,580 a t $30-perbar re l .

Over 90 % of the money that Missourians spend on o i l permanently leaves thes t a t e . For each $30,000 of energy do ll ar s exported we los e one job to a noi l producing st a te or country. This i s 1 ,236 jobs lo st becausewe are not ut i l iz in g th ese two waste products. This is a ser ious drain onMissouri's economy.


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The techn ic ian that const ruced the gen gas un i t had worked wi th a number o fs m a l l e r s i z e u n i t s s i n c e 1 9 7 4 . A f t e r a g r e a t d e a l o f r e s e a r ch a nd e x p e r im e n t a t i o n ,two successfu l sma l l un i t s were f i n a l l y ope ra t io na l . The know1 edge and e xp er ie ncg a in e d fro m t h e s e s m a ll u n i t s was t h e b a s i s f o r a l a r g e r u n i t now s u c c e s s f u l l yo p e r at i n g a t a l o c a l s a w m i ll . A s ys te m d e s ig n p a t e n t has b een i n i t i a t e d f o rt h i s u n i t .

The actua l documented expense fo r the m at er ia ls and pa r t s on t h i s gen gasu n i t i s ap p ro x im a te l y $ 1,900 n o t i n c l u d i n g l a b o r and a d m i n i s t r a t i v e c o s t .Some add i t i on a l pa r ts on hand were no t i n c lud ed i n the co s t . It i ses t ima ted these add i t i on a l pa r t s and supp l ies wou ld add approx ima te ly$300 t o t h e c o s t f o r a t o t a l o f $2,200 f o r m a t e r i a l s . L ab or h o ur s i n c l u d e72 hours t o conver t and adap t the eng ine t o gen gas. Con s t ruc t ion o f th eg a s i f i e r , c o o l e r s , f i l t e r s , and d r y e r t oo k 116.5 h o ur s, t r a v e l t o l o ca t em a t e r i a l s r e q u i r e d 41.5 hours. The t o t a l hou rs came t o 230 hours.

Many r e c y c l e d i t e m s we re u se d i n t h i s g a s i f i e r . We have n o t t r i e d t o f i g u r ea cost based on new ma ter ia ls . " These vary w ide ly ' l f rom p la c e to p lac e becauseo f a v a i l a b i l i t y a nd t h e i n g e n u i ty o f t h e pe op le i n v ol ve d . Depending onma ter ia l s on hand, y ou r c os t may be more o r le ss f o r the same s i ze u n i t .


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COMPONENT PARTS EXPLANATION

This i s a n ex p la n a t io n o f t h e w o rk in g p a r t s i n v o l v e d i n t he c o n s t r u c ti o n o fa down d r a f t g a s i f i e r . T h i s p a r t i c u l a r u n i t r u ns w i t h sa wdu st as a f u e l t h a ti s co nver ted t o a low BTU gas, app roxim ate ly 150 t o 200 BTU/standard c ub icfo ot (SCF), compared t o n a tu ra l gas which c on tain s 1,000 BTU's p er SCF.

Enqine Power LossBecause o f the lo wer BTU con tent , the normal i n te rn a l combust ion engine w i l lbe derated (horsepower reduced) by about 50%. The heat con ten t o f gas f romt h i s saw dust bu r n i ng u n i t does no t g r ea t l y d i f f e r from t h e BTU va l ue o fany ot he r wood fu e l c o n ve rt e d t o gas i n any s i m i l a r a i r i n du c ed wood g a s i f i e r .

The Hearth & A i r I n t a k eThe c o r e o f t h e u n i t o r t h e a r e a where f u e l i s c o nv erte d t o g as i s c a l l e dt h e h e a r t h a re a . T h i s i s t h e a re a where b u r n i n g t a k e s - p l a c e w i t h t h e c o r r e c tamount o f oxygen ad mi t ted t o ma in ta in enough f i r e t o genera te enough heat t og a s i f y t h a t p a r t o f t h e f u e l w h ic h i s n o t r e q u ir e d t o s u s ta i n th e f i r e . Ift oo much oxygen i s a1 owed t o en te r t h e hear th , a1 1 o f t he fue l w i 11 be convertet o carbon d io x id e (C02) and wa ter vapor. The C02 and wa ter vapor w i l l n o tproduce power i n th e engine.

When oxy ge n i n t h e a i r m i x t u r e i n t a k e i s l i m i t e d i n t h e h e a r t h a re a, m ost o fthe wood i s co nver ted t o carbon monoxide (CO), some hydrog en and a few o t h e rcombust ible gases and water vapor. Carbon monoxide plus oxygen w i l l b u r n t oproduce heat and pre ssu re which i s conve rt ed t o pow er i n s i d e an i n t e r na l


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combus t ion eng ine . (Hydrogen and th e ot h e r gen gases w i l l a l s o b ur n, b u t t h ewate r vapor w i l l n o t b u r n ; t h e r e f o r e mo st w a t e r s h o u l d b e re mo ve d b v c o o l i n s t h egen gas . ) A good f i l t e r i s a b s o l u t e l y e s s e n t i a l f o r an i n t e r n a l c om bu st i on en gin e. .

One r e as o n f o r t h e l o w h e a t v a l u e o f t h e p r od u ce of t h i s t y p e g a s i f i e ri s t h a t a i r c o n t a i ns a bo ut 80% n i t r o g e n . N i t r o g e n i s n o t c o mb u st ib l e.

Hear th Component Des ign Explanat ionThe h e a r t h i s wh ere t h e r e q u i r e d b u r n i n g a nd g a s i f i c a t i o n t a ke s p la c e.(See drawing 1, 1~ & 1B)

The h e a r t h a r e a i s composed o f a g r a t e a t t h e b o tt om , a r e s t r i c t e r r i n g ,a com bu st ion z one a nd t h e a i r i n t a k e n oz zl es , r e f e r r e d t o i n t h e l i t e r a t u r eas I ' toures l ' . '

The h e a r t h i s a c y l i n d r i c a l shape, e s s e n t i a l l y o ne c y l i n d e r i n s i d e a no t he r w i t ha s pa ce b et we en t h e c y l i n d e r s f o r p a ss ag e o f i n c om i ng a i r .

The g r a t e s u p p o r t s t h e f u e l . I n t h i s u n i t t h e g r a t e i s a d i sc a rd e d ham merm ills cr e en l o c a t e d a f ew i n c h e s be lo w t h e r e s t r i c t e r r i n g , a nd i s t h e same d ia m e t e ras t h e s m a l l e s t c y l i n d e r .

A h e a t s e n s i n g d e v i c e ( p y r o m e t e r ) i s i n s t a l e d i mm ed ia te ly be1 ow t h e r e s t r i c t e r ,b u t a b o v e t h e g r a t e a n d e x t e n d i n g i n t o t h e h o t t e s t ar ea o f t h e g r at e. 'Thep y ro m e te r me as ur es t h e e f f e c t o f a n y c ha ng es o r a d j u s tm e n t s made i n a i r f l o w


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t h a t c ha ng es o p e r a t i n g t e m p er a tu r e . The op er at in g temp erature of mos t gengas u n i s i s 2 ,3 72 '~ t o 2 ,6 42 '~ a t t h e h o t t e s t p a r t o f t h e h e ar th . (Seegen gas book, pg. 116&119. I n t h i s u n i t t h e p y r om e te r r e a d i n g r a ng es b etw ee n1,100 t o 1 , 2 0 0 ~ ~ecause i t i s n o t i n t h e h o t t e s t h e a rt h zone.

The r e s t r i c t e r r i n g o u t s i d e d ia m e te r i s t h e same s i z e as t h e i n s i d e d ia m et ero f t h e s m al l e r c y l i n d e r . T he re i s a s m al l h o l e i n t h e c e n te r o f t h e r i ng ..T h i s h o l e c o n t r o l s t h e v olu me o f t h e c o mb us ti on a r e a and a l s o c o n t r o l s t h ev e l o c i t y o f t h e gen gas t h a t f l o w s t hr o u gh t o t h e e ng in e. T h is f l o w r a t edoes i n f l u e n c e t h e h e a t g a i n e d by t h e g as p a s s i n g t h r o u g h . If he gas dw e l l st o o l o n g i n t h e c o m b us ti on a re a , a h i g h e r p o r t i o n o f t h e ga s becomes no n-comb us t ib le C02 . L i kew ise , i f t h e gas f l o w s t o o s lo w t h e f i r e r u ns t o o c o ola nd m ore o f t h e ga s pa ss es t h r o u g h as t a r , i n va p or fo rm , i n s t e a d o f c o n v e r t i n gt o CO and hydrogen. A d d i t i o n a l l y , if h e gas f lo ws t o o s lo w t h e ash w i l l b u i l dup on t h e g r a t e a nd u l t i m a t e l y w i l l choke o f f t h e f l o w o f i n co min g a i r . Amanual 'l y c o n t r o l l e d shaker sys tem w i l l h e l p e l i m i n a t e ash b u i l d up.

The n e x t v e r t i c a l s t e p u p t h e h e a r t h cha mb er i s t h e a i r n o z zl e r i n g . Thesen o zz le s pass t h ro u gh t h e f i r s t ( i n s i d e ) c y l i n d e r w a l l and i n t o b u t n o t th ro 1 lg hth e ho l low chamber between t h e tw 3 c y l i n d e r s . A i r nozz le s shou ld be made o fm a t e r i a l s t h a t a r e h i g h l y r e s i s t a n t t o h i g h t e mp era tu re . The number of a i rn o z zl e s, t h e i r d i am e t er and t h e h e i g h t above t h e r e s t r i c t e r r i n g i s p r ed e te rm in e db y a m a th e ma ti ca l r e l a t i o n s h i p t o t h e s i z e o f t h e e ng in e . S i z e o r e n g i n evo lu me i s d e t e rm i n ed b y t h e b o r e, s t r o k e a nd r e v o l u t i o n s p e r m in u t e o f t h eeng ine you a r e ope ra t in g . See Tab le 29327 and F ig ure #77 , pg. 123, 125, and 126fo r th e mathema t ica l formu las i n th e Swedish Gen Gas Book (Sw. GB) se c t io n.


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A l l m a t e r i a l s i n t h i s h e a r t h are a a re m i l d s t e e l e x c ep t f o r t he n o z zl es , w h ic ha r e s t a i n l e s s s t e e l a nd t h e g r a t e w h ic h i s h i g h c a rb on s t e e l .

Gen Gas Housing ComponentThe next component (see drawing 2A & 2B ) i s t h e gen gas hous ing and combina t i onf u e l s t o r ag e c o n t a i n e r. The h ou sin g i n t h i s u n i t i s a c y l i n d e r . The h e a r t hu n i t ( g r a t e , r e s t r i c t e r r i n g and a i r n o z zl e) i s p l ac e d i n s i d e th e h ou sin g w i t ha space between the two cy l i n de rs . The space a1 ows the down tube a i r i n t ak ep ipes to ex tend from the to p o f t h e fue l b i n down t o n e a r t h e b o tt om o f t h er e s t r i c t e r r i n g . Th i s down tube a l l ows the a i r t o be p reheated as i t r a v e l sdow n t he t ubes and t h r ough t he ou t s i de hea r t h cy l i nde r and up t he ho l l owcham ber t o t he nozz les . Th i s a l so he lps t o coo l t he e x i t gas.

The above m en ti on e d a i r p r e h e a t i n g i s i m p o r t a n t, e s p e c i a l l y f o r e n g in e s t h a to p e r a te i n t e r m i t t e n t l y as i n sawmi 11i g o p e r a t i o n s .

As the eng ine i d le s , t he a i r moves more s lo w l y th rough the gen gas combusti ona re a r e s u l t i n g i n a s m a l l e r f i r e . When t h e e n gin e t h r o t t l e c a l l s f o r m oref ue l t he vacuum i ns i d e t h e eng i ne i s i nc r eased c a l l n g f o r a sudden changei n a i r f l o w . T h i s demand f o r i n c r e a se d f u e l r e s u l t s i n a q u ic k s u rg e o fo u t s i d e a i r i n t o t h e h e a r t h and o cc urs m ore r a p i d l y t h a n t h e f i r e ' s a b i 1i yto respond. T h i s r a p i d a i r change r e s u l t s i n f u r t h e r , b u t te mp ora ry c o o l i n g .C o o l i n g r e s u l t s i n l e ss com p le te conve r s i on t o gas , w h ich i n t u r n means ani n c re a s e i n t a r p r o d u c t i o n . T h is c o m b in a ti on o f r e a c t i o n s means t h a t a g r e a t e ramoent o f b o t h w a t e r v a p o r and t a r may r e a ch t h e e n g i ne r e s u l t i n g i n s t i c k i n gp i s t on r i ng s , va l ves and push r ods . Th i s r e su l t s i n con t am i na t i ng t he eng i il eo i l w i t h t h e a s s o c i a t e d p ro ble ms o f i n c r ea s e d w e ar in g o f a l l m o vin g s u r fa c e sa n d h a r d e r s t a r t i n g .


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The c o mb in a t i o n o f wa te r v ap o r and t a r t e n d t o c a r r y a h i g h e r p e rc e nta geo f v er y f i n e p a r t i c l e s o f ash. The water has a tendency t o c a rr y asht h r o u g h t h e f i l t e r s . A i r p r e he a t i s i m p o r t a n t and e v e r y t h i n g p r a c t i c a ls h ou ld be done t o r e t a i n u n if o rm t e mp e ra t ur e i n t h e h e a r t h a re a, e s p e c i a l l yw i t h i n t e r m i t t e n t e n gi ne o p e ra t io n .

A surge ta nk o r some supp lemental fue l w i l l he1 p overcome th e r a p id changeo f t h e f l o w o f c o l d a i r t h ro u g h t h e h e a r t h a re a ( s ee d ra w in g # l o ) .

Ash P i tThe gen gas hous ing ash p i t a l so a1 ows passage o f t he gas between th eh o u s in g and t h e h e a r th an d a l s o f u n c t i o n s a s a p re h e a te r f o r t h e i n co m in ga i r tu be s.

When i n s t a l l i n g t h e g ra te , a l l o w some sp ac e be lo w th e g ra te f o r as haccum ula t ion . Th is space shou ld be la rg e enough f o r a minimum of oneday o p e ra t i o n s . Co n s id e ra t i o n s h o uld be g i v en t o sh ap e i n t h e a shchamber. The s l o we r t h e a i r moves i n t h i s s pa ce t h e more a sh i s r e t a i n e dc l o se t o t h e p o i n t o f b ur ni ng . Th is reduces the amount o f ash t h a t movesw i t h t h e gas an d re du c es t h e l o a d o n t h e f i l t e r s a nd c o o le r s . (See Page CAppendix)

R ap id c o o l i n g o f h o t gases i n t h e l o w e r p a r t o f t h e h ou si ng p r e ve n t s C3f ro m re fo rm in g i n t o C02. On th i s u n i t t h e gas l e a v es t h e gas e x i t p o r ta t approx imate ly 300 F, i n d i c a t i n g a r a p i d gas t e mp e ra tu re d ro p b elowt h e 1400 F l e v e l , below which C02 fo rn is very s lowly .


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The shapes discussed above have a1 1 ment ioned cy l i ders . Other shapescan be use d b u t a c i r c l e i s the most e f f i c i e n t des :gn f rom the s tand .p o in t o f e n c lo s e d volume v ers u s sq ua re f e e t o f ma te r i a l u se d. A i r f l o w sa r e m ore u n i f o r m i n c i r c u l a r c o n t a i n e rs t h an i n o t h e r shapes b u t o t h e r shapesh av e b ee n u se d s u c c e s s fu l l y , e s p e c i a l l y f o r t h e h o u s ing . It w o u ld b e b e s t t ouse a c i r c l e f o r t h e i n s i d e d ia mete r o f t h e r e s t r i c t e r r i n g . N o z z le e x te n s io ni n t o c o m bu st io n a r e a c an b e s h or te n ed o r l e n gt h e ne d t o c i r c u l a r shape t o c on -t r o l t h e co ne s ha pe a nd vo lu me o f h o t c o a l s .

Weld ing rod s sh ou l d conform t o he at requ i r eme nts o f th e component members.(U se h i g h t e m p e ra t u re r e s i s t a n t m a t e r i a l o n t h e n o z z le s a nd h e a r t h a re a , u n l e s st h e i r s hape a1 o ws t hem t o b e i n s u l a t e d b y t h e f u e l o r t h e a sh .)

The gen-gas h o u si n g may c o n t a i n a l i d i n a d d i t i o n t o t h e h e a r t h , a i r t u b es , a sh- - -~ i tnd thi g as le x i t p o r t . - A 1 d do es - n o t seem t o i m pr o ve t h e o p e r a t i o n w i t h

sawdust f u e l b u t may p r o t e c t t h e u n i t fr o m w i n d o r r a i n .

I f s m a l l p i e c e s o f wood a r e used as f u e l , o r i n m o b i l e v e hi c l es an a i r t i g h tl i d i s r e q ui r e d. T h i s p re v e n ts b y p as s ing t h e a i r t ub e s , t h u s a v o id s ch a n g in gof de s ia n c r i t e r i a . - ~ n y i d sh o ul d have a s p r i n g t e n s i o n o r w e ig h t t e n s i o nf a c t o r i n t h e ev e nt o f f l a s h back. F l a sh b ack i s a n e x p l o s i on r e s u l t i n g f r o ma cc um u la te d (rases i n a c o l d g e n e r a to r o r c o u l d r e s u l t f r o m r a p i d s h u t down o n t h es u c t i o n s i d e o f t h e g e ne ra t or . F l a s h ba ck has n o t be en a b i g prob le m, b u t l i k ea1 1 s a f e t y d ev ic es i t ' s b e t t e r t o b e s af e t h an s o r r y .

The f u e l r e s e r v e needs t o b e d es ig ne d f o r s e v e r a l h o ur s o f u se . Too l i t t l esawdust and the hopper must be f i 1 e d more o f t e n i n a b a tc h feed , too much


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causes excess compac tion r es u l t i ng i n reduced a i r f l ow . T h is i s n o t a s e r io u sprob lem w i t h chunk fu e l bu t compac tion can be a prob lem, es pe c ia l l y w i t h wetsawdus t o r sawdus t tha t con ta ins a l o t o f f i n e s f ro m a s an di ng o p e ra t io n .

Cyclone Ash RemoverL oc at ed i m n e d i a t e l y a f t e r t h e h o u s in g i s e i t h e r a b a f f l e t y p e as h re mo ver o r acyc lone type ash separa to r (o r bo th ) ( see d raw ing #3A and #3B). The ashremover shou ld be as c l ose t o t he hous ing as p oss ib le . Ash i s removed moste ff e ct iv e ly be fo re th e gen-gas coo ls down t o the dew po in t . The ash removerdoes ac t as a coo le r , bu t t h i s i s a secondary func t io n .

The u n i t d iscussed here does no t have a water spray b ath for ash and t a r re -moval , bu t a we1 1 des igned .and mainta ined spray o r counte r f low water bath i st h e m os t e f f e c t i v e way t o remove f o r e i g n m a t e r i a l s . The b a th s h a ~ l d e i n -s t a l e d p r i o r t o t h e c o nd en so rs and c o o l e rs t h a t r e du ce t h e gas t o f i n a l d e s ig ntemperatures (1040F). . I f t h e w a te r b a t h i s t o o c l o s e t o t h e e n gin e i n t h e f l o wc i r c u i t : , i t w i l l be i m p o s si b l e t o c o o l t h e gas s u f f i c i e n t l y be lo w t h e dew p o i n tto remove excess water vapor. A smal l amount o f water en ter ing the engine asv ap or does. n o t i n t e r f e r e w i t h e n gi ne o p e r a t i o n . Too much water vapor w i l l con-dense ou t on c o l d engine sur face s. This condensing out can be a problem bothwhen s ta r t i n g up the engine and a ls o wh i le th e eng ine i s runn ing . The p rob lemi s g r e a t e r i n p e r io d s o f h i g h h u m i d it y o r v e ry c o l d t em p er at ur es .

The major problems a re t h a t incom ing a i r may be coo le r than your gen-gas. Thei nc om in g a i r may a l s o be h i g h i n r e l a t i v e h u m i d it y . When the cool a i r mixes,th e gen-gas tem per atur e may be reduced below th e dew p o in t . Any cold enginesurfaces further reduce the temperature and water vapor becomes 1 i q u i d w i t ha l l o f i t s a s s o c i at e d p ro ble m s.


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The need to remove water vapor from the gen-gas cannot be over emphasized.Regardless o f the operating tem perature, gen-gas i s always a t 100% r e l a t i v ehumidity , fur ther cool i ng produces 1 iquid water.

Another reason f o r cooling below 1 0 4 '~ i s t h a t gas becomes denseron cooling, which has the beneficial effect of containing more energyper cubic foot . This gives greater power per revolution of the engine.With the engine possibly derated about 50% fo r gen-gas o perat ion, add it iona lloss o f power i s very detr im en tal .Heating the gas mixture by l o O c (1 8 '~ ) causes a power l oss of 3%. Avoid severeflow resistance; a pressure drop o f 100 mm (3 .9 3 inches ) of water or .I48 poundsof pressure would cause a power loss o f 1%. Small didmeter pipes increase flowr e s i s t a n c e .

-Cooler CondensorIn the uni t we ar e d iscussing, the next f ix tu re i s a square tube (see drawing#4 & #S) coo ler condensor. Square tubes ar e not necessary b u t are-convenient

to workwith. This coo ler has 1 2 tubes , baf f led t o form an " S " shaped flowpat t e rn o f 4 tubes flowing on each level of the "S". Since the gas is coolingi t i s a ls o condensing water , the water flows with th e gas and drops o u t i n t othe condensate tank. The condensate i s drained pe rio dic all y.I t would be beneficial t o add a t le a st four more horizontal tubes to the coolercondensor.A fte r th e cond ensate tank we have a s p l i t flow pat te rn . One l in e to thes t a r t e r f an , one l in e to the o i l bath f i l t e r and then t o the engine.These two lines can be closed o f f from each other by a set of manuallyo ~ e r a t e d a l v e s .


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S t a r t i n g F a nThe s t a r t i n g f a n ( d r a w i ng #6) i s an o l d up r i g h t type vacuum sweeper motor, connectedt o 110-120 v o l t e l e c t r i c i t y . A u t o m b i l e h ea t er f an s have been used i n o t h e r u n i t s ,and operated from t h e s t o r a g e b a t t e r y . S u c t i o n f an s p e r f or m b e t t e r t h a n p r e s-su r iz ed systems. Leaks i n a suct ion system may reduce combust ion e f f ic iency buta pressure system leak may force gas such as oxygen depleting COP, poisonous CO,o r e x p l o s i v e h y dr og en i n t o t h e b u i l d i n g .

Be c e r t a i n t o v e n t y o u r s t a r t i n g f a n h i g h enough and i n t h e r i g h t w in d d i r e c t i o nt o p r e v e n t gen-gas f ro m a c c um u l at in g i n b u i l d i n g s . The gen-gas b u i l d i n g i t s e l fs ho ul d be we1 1 v e n t i a t e d , b o t h t o p and b ot to m. A v o id w in d d r i f t t o o t h e rb u i 1d i ngs where gen gas may accumulate.

A s ma ll a i r cock j u s t a f t e r t h e f a n w i l l a1 low te s t in g the f l ame o f t he gasb e f o r e a t t e m p t i n g t o s t a r t t h e e ng in e. A f t e r t h e gas s u p po r ts a good f la m e t h eengine w i 11 us ua l l y s t a r t on the gen gas. You probably should cons ider ass is tan ceusing gas01 i ne o r p ro pan e f o r e a s i e r s t a r t i n g .

O i l B a t h F i l t e rA f t e r t h e gas b urn s r e a d i l y a t t h e s t a r t i n g f a n t e s t cock, t h e gas i s d i v e r t e dt o t he o i 1 b at h f i l t e r (d ra win g X 7 ) . T h is i s a s ta nd ar d t r u c k f i l t e r . Anygood o i 1 b at h f i l t e r o f s u f f i c i e n t c a pa c it y sh ou ld work. A horsepower matchshou ld be a conven ien t method o f s i z ing . I f the horsepower in format ion i s n o ta v a i l a b l e , a i r f l o w wo ul d need t o be c a l c u l a t e d .

Engi ne Condensate DrainA f t e r t he o i l b ath fi e r , the gas f l ows toward the engine . Ju s t be fo re o ra t t h e b o tt om o f t h e f i n a l f i l t e r i s a d r a i n cock f o r c on de ns ate . T h is removesa cc um ul at ed w a t e r a t t h e f i n a l f i 1 e r , r e d u c i n g the amount o f water vapor a tt h e e n g i n e . 1 1


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Surge Tank - Reserve FuelThe surge tan k (se e drawing d 8 ) ' . i s a tank l a rg e enough to ho ld enough gengas t o a l l ow a f as t eng i ne speed r ecove r y . Because o f t h e d i s ta nc e be tweent h e gas g e n e ra t o r and c a r b u r e t o r i n t h i s s p e c i f i c s e tu p t h e r e w i l l be ade lay i n gen gas reach ing the eng ine . The surge tank on t h i s sys tem( app r ox i m a t e l y 3 ga l l o ns ) has p roven t o be too sm a l l f o r t h i s eng ine ;c o r r e c t s i z i n g o f t h e s ur ge t a n k has n o t been d e t e n i n e d .

From the surge tank the gen gas passes th roug h a fo u r i n ch d iameter p l a s t i cp i pe . T h i s p i p e i s f i l l e d w i t h re m ov ab le an d w as ha ble p l a s t i c d is h w as h in gki tc he n sponges. These sponges can be washed i n d ie se l f u e l and reused.T he re i s a l s o a v a lv e on t h e b ot to m o f t h e f i l t e r f o r c on de ns ate d r a i n a ge .

. (see draw ing # Th is i s minimum f i 1 e r i ng and needs t o be improv ed.

Carbure to r Man i f o l dThe f i n a l f i x t u r e o f t h e gen gas s y ste m i s t h e c a r b u r e t o r m a n i f o l d w i t h tw oaccesso ry ca r bu r e t o r s , one p ropane and one gaso l i ne ( f o r a i r m i x i n g on l y ) .The m a n i fo l d a l s o a ll o w s f o r a f r e s h a i r i n t a k e f o r b l e n di n g w i t h t h e gen g as.The ca r b u r e t o r gen gas m an i f o l d se t s on t op o f t he o r i g i n a l t r u c k m o to rc a r b u r e t o r . The t r u c k m o t o r i s a 1954 i n t e r n a t i o n a l 450 c u b i c i n c h "R "se r i es . The motor was chosen because of f a m i l i a r i t y a long w i th capab i 1i ya n d d u r a b i l i t y . Eu r opean expe r i ence i nd i ca t es t ha t s l ow speed l ong s t r okeeng ines pe r fo r m be t t e r w i t h gen gas t han h i gh RPM eng ines .

Th i s eng ine has the ca p a b i l i t y o f r unn ing on gen gas , g aso l i ne and/or p ropanei ndependen t l y . The eng ine cou ld ope ra t e on any com b ina t ion o f t h r ee f u e l s byproper manua l m ix ing o f f u e l s . T he re i s n o c ro s s l i n k a g e o f f u e l s ys te ms , b u tt h e r e a r e manual c o n t r o l s c o n v e n ie n t t o t h e saw c a r r i a g e f o r o p e r a t o r a d j u s t -ment if dd i t i o na l power i s needed.


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T h i s u n i t w i l l n o t r u n a t i d l e w i t h o n l y t h e s m all p e t r o l ( g as o li n e) c a r b u re t o r( app r ox i ma t e l y 8 HP ) on the square tube man i fo ld . Th i s smal l gas o l i n e carb ure tori s d esig ne d o n ly f o r s t a r t i n g . The propane carburetor serves the same s tar t ingf unc t i on , bu t can keep t he eng i ne r unn i ng a t i d l e speed and i s c apab le o fr u n ni n g th e e n g in e a t f u l l power b u t i n p r a c t i c e i s u sed p r i m a r i l y a s a p owerboos t f o r peak l oad i ng o f t h e s aw.

A1 coho1 f u el s co uld a ls o be used throug h a smal l ca rbu ret or , o r a superc ha r ge r t o ga i n ad d i t i on a l hor sepower. A super charger w i thout supp lementa lfue l ass i s ta nce wou ld re qu i re a 70% inc rea se i n gen-gas consumpt ion (Sw . GB ) .

One o t he r way t o overcome hors epower de f i c i en c y i s t o s t a r t w i t h a l a r g e reng ine th a t cou ld supp ly the power needed, a f te r t he necessary de ra t i ng w i thgen-gas. A tandem engine could a lso be used wi th be1t d r i v e p u l le y s .

Most U.S. e qu ip me nt i s g r e a t l y o v e r si z ed , d e r a t i n g i s t h e r e f o r e n o t as1de t r ime nta l as most peop le wou ld imagine .

To t a l av oi dance o f t he use o f gas o l i ne wou ld enabl e t he eng ine t o r un on c l eane rburn in g gen-gas thus av o id in g spark p lu g depo s i t s and o i l co n taminat i on from theby - pr oduc t s o f bu r n i n g gaso l i ne .

Propane does no t have these o i l po l 1u t i n g c ont am inant s o f gas ol i e bu t i s morecos t ly than gen-gas .

Engine AdjustmentsThe eng ine has n o t been a l t e r ed except t o advance the t i m in g approx imate l y fo urt o f i v e degr ees be f o r e normal f i r i n g t o c ompensate f o r t he s l ower bur n o f t hegen-gas.


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Engine power cou ld be improved by i nc rea s in g the compress ion ra t i o s i n t hec y l i n d e r . Compress ion ra t i os o f 10 o r 11:l have been suggested. It wou ldbe a dv i s a b le t o c o n t a c t t h e m a nu fa c tu re r b e f o r e d e c i d i n g on a f i n a l r a t i o .

I n gen-gas ope r a t i on a s t anda r d gaso l i n e eng ine i s de r a t ed t o abou t701 o f i t s r a t e d power. T h is r e d u c ti o n i s p r o ba b ly due t o d i f f e r e n t b u rn i ngch ar ac te r i s t i c s o f gen-gas compared t o gaso l i e. However, th e en gi ne w i 11r u n on ra t h e r w id e a i r / f u e l m i x t ur e l i m i t s . Excess o r d e f i c i t a i r m i xt u re sw i l l cause a f u r t h e r l o s s o f pow er. Imp rop er l y coo led gas (above 104 '~ ) o ran e xc e s s i v e ly h i g h i n t a k e m a n i f ol d t e m pe r a tu r e o r a l o s s of s u c t i o n p r e s s u rec a u s e d b y r e s t r i c t i v e p i p e s a n d e l bows may cause f u r t h e r power los se s, a1 1o f wh i ch cou l d t o t a l up t o as much as 50% power loss. W i th r e a so n ab le g a s i f i e rd e s i g n a n d r e a s o n a b l e a i r j f u e l r a t i o s i t seems l o g i c a l t h a t 60-65% o f norma lpower can very 1i e l y be ach i eved w i t ho u t changi ng t he com press ion r a t i o . I ngenera l , c o o l i n g t h e g as a n o th e r 1 0 ' ~ w i 11 improve th e power because co ol ergas g i v e s a n i n c r e a se d f u e l c ha rg e i n t h e c y l i n d e r a nd a l s o he1 p s t o r ed u cecondensate t h a t occur$ when co o le r a i r ente rs th e warm gen-gas st ream. I ft h e a i r s t re a m i s a t t h e same t e m p er a tu r e as t h e gen gas, l i q u i d d ro p o u t ( ascondensa te ) shou ld n o t be a p rob lem. . .

-- -The I n t e r n a t i on a l H a r ves t e r D i s t r i b u t o r recommends a low ash o i l f o r gen gasuse . Because o f t h e p o t e n t i a l f o r w a t er c o n t a m in a t i o n t h e e m u l s i f y i n gq u a l i t i e s o f t he c r ankcase o i l shcu l d a l s o be known. Some o i l s coag u la teand f o r m j e l l y w hen c o nt am in a te d w i t h f a i r l y s m a ll amounts o f w a t e r. I f t h ec rankcase o i l t u r n s t o j e l l y t h e en g in e lo c k s up i n a ve ry s h o r t t im e .

M o t or o i l i m p u r i t i e s a r e of tw o m a in c a t e g o r i e s .1. Mechanical - abras ion and /o r chemica l .

a . I r o n p a r t i c l e s ( bu rs , s ha vin gs , g r i n di n g s , s l i v e r s ) .5 . R u s t ( f r o m c h e n i c a l a c t i o n ) .


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2. O i l Th icken ing Agen tsa. D us t f ro m a i r i n t a k e ( s i l i c a , e t c . ) .b . Dust o r i g i n a t i n g i n t h e f u el - s uc h as s i l i c a , q u a r t z , p o ta sh ,

phosphate, copper, z i nc , carbon, mangaenze, et c .

Tab le 28 f rom t he Swedish Gen-Gas Book p o in ts ou t the ex te nt o f th e problemw i t h d u s t a nd o i 1 c rankcase con tam ina t ion .

T ab le 28. DUST CONTENT OF A I R

A i r Contam ina t ion i n mg/m 3

Rural areas and suburbs ................................. 0.5 - 1...................................................i t i e s 2......................................n d u s t r i a l c e n t e r s + 4..............................t r e e t s w i t h h e a v y t r a f f i c = 20D u s t y h i g h w a y s , e x c a v a t i o n a n d g r a v e l p i t s

. . - - .- ..farm w ork w i t h t r a c t o r s , e t c . .......................... over 200-- - -I n the case o f 200 rng dus t pe r m3 a i r , a c a r w i t h a 2 l i t e r ( 310 cu. i n . )engi ne would, when d r i v i n g 100 km (6 2 m i . w i t h o u t an a i r c l e a n e r , s uck s i n26 gm o f du st. Some of t h i s c o n t a m i n a t i o n c an f i n d i t s way i n t o t h e c ra n kc a seo i l , caus ing o i 1 t h i c k en in g and subsequent wear. (Note, 26 gm = .9 oz. o f d u s t )

Be a l e r t t h a t y o u r o i 1 pr ob le ms when u s i n g g en -g as f u e l may i n r e a l i y becaused by p o o r l y ma in ta in e d a i r i n t a k e f i l t e r s . A s a w m i ll i s a v e ry d u s typ l a c e, a nd q u a l i f i e s as about equa l t o h ighways and g rave l p i t s .

1 5


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Energy Balance of Wet SawdustA i r d r y , o r d r i e r sawdus t w i l l i mp rove t he gen -gas com bust ion e f f i c i e nc y .Every pound of wa ter conv er ted t o vapor (assume 70' ou ts i de a i r temperatureand 70' sawdust temperature) req ui r es 1,112 BTU's o f energy. To d r iv e a l l themo istu re ou t o f s i x pounds of f resh green wood (use above temperature) t h a tconta ined 501 of m oisture , would req u i r e 3,336 BTU's. One horsepower f o r onehour req u i re s 2,545 BTU's w i t h no l os s fo r e f f i c i e nc y . Ano ther way t o s ta tet h i s i s t h a t i t r eq u i re s 1.3 horsepower to com ple te l y d r y s i x pounds o f 50%mo istu re wood. The e n er gy r e q u i r e d t o d r y t h e wood i n t h e g a s i f i e r i s l o s t .Howeve r, w as te hea t f r om t he eng i ne exhaus t can be recove r ed t o p a r t i a l l y d r yth e wood fue l as p r ev io us l y d i scussed.

I n th e f u t u r e we a n t i c i p a t e t h a t a l l f u e l s w i l l be s o ld on a BTU ba si s, perhapsi n c l u d i n g wood r es i du e . To show t h e e f f e c t o f d r y i n g t h e s aw du st p r i o r t oga s i f i c a t i o n , cons i de r t h a t g reen oak has a m o i s t u r e con t en t o f 50% and a BTUva lu e o f 4,300 BTU/ lb. I f t h e wood i s d r i e d t o 25% m o i s t u re a t n o c o s t u s i n gexhaust gas waste hea t recov ery, th e heat va lu e i s now 6450 BTU/lb., a 150% :i nc rease . I f saw dust i s p r i c ed a t $l O /t on , t hen :

l'oM)'OOO = $l.l6/nmBTU (mn = one m i l l o n )OOO#/T x 4300 BTU/#

I f t h e s a wd us t i s d r i e d t o 2 5% m o i s t u r e a t n o c o s t :

As you can see, t he c os t o f energy has been. reduced by 1 /3 by u s i n g h ea t t h a tu s u a l l y i s w aste d. Als o n ote t h a t th ese pr ic e s compare w i t h $S.OO/mmBTU f o rna tu ra l gas ( a t SO@/ therm) . Fur the r , i f y o u r c o s t i s o t h e r t ha n $ l O /t on ,s i m p l y p u t t h a t v a lu e i n t h e p re c ee d in g eq ua sio ns t o c a l c u l a t e y o u r s a v in g .


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S t a n d - B y E l e c t r i c i t yP l ans have been made by t he ope r a t o r f o r a s tand - by e l e c t r i c gene r a t o r t h a tcan be o p e ra t ed f ro m t h e ge n-gas u n i t . T h i s i s in t e n d e d t o p ro du ce e l e c t r i c i t yf o r s t o r a g e when t h e e n g i n e i s i d l i n g be tw ee n saw c u t s . D e t a i l s o n h o o k up have.n o t be en c om p le te d a t t h i s d a te .


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-EA?T-I la' H / G + J ~ ~ " D I A . ,ADE OF &"STOCK


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''11,NOTE:AIRNOZZLES z i . D. S ? A I N L E ~ SPIPE4 EA. 5 IN,LONG, 8 EA . 1 IN. LONG


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DEPARTMENT OF NATURAL RESOURCESENERGY NOTE

The fo l l o w i n g p r i n te d ma te r i a l , pp. 116 t h ru 1 29 and n o te d asChapte r 5; "Coo l ing and C lean ing o f Genera to r Gas" i s re p r in te df rom a book e n t i t l e d "Generato r Gas - The Swedish Experiencefrom 1939 t o 1945." (See a l so pp. 165 t h r u 170)

T h i s p u b l i c a t i o n was t r a n s la te d by S o la r E ne rg y Res ea rc h I n s t i t u t e ,1536 Cole Boulevard , Golden, Color ado 80401. Copies can be ob ta in edf rom the Na t iona l Techn ica l I n fo rm a t i on Serv ice , U.S. Depar tm in to f Comnerce, 5285 P or t Roya l Road, S p r i ng f i e l d , V i r g i n i a 22161.

I n t h i s s e c t i o n , t h e ma th ema ti cs a re b as ed on me t r i c u n i t s . Thefo! ' tow inq conve rs ion fa c t o r s can be used t o co nve r t t o conven t iona lu n i ts .

CONVERSIONS FOR READING THE SWEDISH GEN-GAS BOOK(We s ug g es t y o u buy a me t r i c c o n v e rs i o n t a b l e f o r r e fe re n c e )

1 BTU = amount o f h e a t n e ce s sa ry t o r a i s e t e mp e ratu re o f one l b . o fwa te r 1 ' ~

1 KW = 3,413 BTU1 HP = 2,545 BTU1c = 1 . 8 ' ~ t 32 -

Example ( 6 0 ' ~ x i. ) + 32 = 140'~


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1 cubic ft. water = 7.481 gallons = 62.47 Ibs.1 cubic ft. = 1,728 cubic in. -

= .0283 cubic meters [m3)-- . . . .

1 M~ = 35.31467 cu. ft. = 61,023.75 cu. in.1 L (liter) = 1,000 ml (milliliters) = 1.0567 qt.1 qt. = .94635 L = 946.35 ml.= 32 fl. 02.1 cu. in. = 16.387 cc1 cc = .06102 cu. in.1 mile = 5,280 ft. = 1.6093 Km (kilometer)1 Km = 3,280.9 ft. =.62 miles = 1,000 M (meters)1 M = 100 cm (centimeter) = 3.28 feet = 39.37 in. = 1.0936 yards1 ft. = 30.48 cm = 304.8 mm (millimeter)1 inch = 25.4 mm = 2.54 cm1 mph = 5,280 feet per hr. = 88 ft. per min. = 1.4666 ft.

per second = ,447 meters per second1 Kmph = 3,280 ft. per hour = 54.666 ft. per min. = .911 ft. per second .1 meter per second = 196.8 ft. per min. = 11,808 ft. per hour.

= 2.236 mph1 Ib. = 16 oz. = 453.592 g (gram)1 kg (kilogram) = 2.2046 lbs. = 1,000 g = 35.27396 oz.1 g-, = .035274 ounces1 oz. = 28.349 g

Note: Unit cc is beinq discouraqed as a liauid measure, rnl (milliliter) s-preferred under rules of the new 5 . I. (Systems ~nternationai.) ~i ter ( L 1-7; to

. -. . . - - A -,used only for 1 iquid measurement since one 1 iter of water weighs one kg at nonr:1conditions. i


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THE HAZARDS OF GENERATOR GAS OPERATION - G A S P O I S O N I N G

These are essent ia l l y th ree hazards connec ted wi th gen-gas : 1 ) f i r e2 ) t r a f f i c and ( 3 ) t ox i c haza rds .

The f i r e haza rd a r i se s by d i sca rd i ng h o t ashes o r l o ca t i n g ho t p ipes tooc l o s e t o c o m bu s ti b le m a t e r i a l s . I n v e h i c l e gas g e n e r at o rs i n v o l v e d i nc o l l i s io n s t h a t cause over tu rn s , the gen-gas u n i t f r eq ue nt l y dumps openf lame onto the acc iden t scene. Rear end c o l l i s io n s o f te n pop the sa fe tyl i d and h o t ashes a r e f o r ce d o u t o f t h e f u e l h op pe r. T h i s i s e s p e c i a l l ybad i f one o f t h e a ut os s p i l l g a s o l i n e from t h e f o r c e o f t h e a c c id e n t .

The t o x i c haza rd i s p r im ar i l y ca rbon monoxide po i son ing . Carbon monoxidei s odo r l ess and co l o r l ess and cannot ea s i l y be detec ted . Acu te po i son ingsymptoms o f CO ar e reasonab ly easy t o d iagnose. C h ro nic t o x i c i t y on t h eo t he r hand can occu r ove r l ong p e r i ods o f exposure a t l ow concen t ra t i onsthus masking the symptoms and therefore can be over1ooked o r impr oper lydiagnosed. On ly a sh or t exposure i n an envi ronment c on ta i n in g a few hundredto f a pe rcent by vo lume i s enough t o cause acu te po ison ing . Acute carbonmonox ide po iso n ing can occur a t con cent ra t ion s above 0 .05% (500 pa r ts pe rm i l l i o n ) . A t t h i s le v e l and above, unconciousness res u l t s , death may beimmediate and th e po ison ing e f f e c t i s comparab le t o an acu te b ra in hemorage oan acu te he a r t a t t ac k . S t a t i s t i c s i nd i c a t e t h a t au to mechanics and chau fferswere f re qu en t l y v i c t i m s o f ca rbon monoxide po i son ing . T h i s a l s o l e ad s t o g ri nc i dence o f t r a f f i c acc i den ts because o f reduced rea c t i o n t ime and d rowsine


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SWEDISH GEN-GAS BOOK SECTION


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heertfis ?rcved c be durable enough tor aopruximately ?O,J00 kn of bus operation duzirqpredorninant!y high load. Since the circumstanc~ f crisis made it necossarl to elimi-nate t9e ni&el admixture altogether and to limit t?e chrome content t o 6 % , the dumbil-ity of the heach was dectessed to aporoximattly ?,000 k n . However, duF;sg ogerztionof ?rivate csn with generslly low load, the durabzty was severd 3ne s Fest er and, onthe whole, satisfactory..TZle unsatisfactory durability of the hoqhss-skaged alloyed hoo r . ? s is caused 3y :hefollowirq:L -4 shape that cause3 thermal strest in the material and Wing uceven and ouiedheating causes cac.b and deformation.2. The poor heat conductivity (aggmsiaateLy ha l l of the ordinary C S S S ~ ~ ) ,whichcausa t5e hearth to w q urirq uneven heatirg; i.e., in case of local overneatir~due to air leaks in the c!eaning doon, g ipes to the air nozzles, or at connection

dangu*3 . Gneven nix irg of the c0nponen.U contained in :Se casting. Special, ~ t a t i n qur-naces are reqcird to provide even mixirg.One very obvious disadvantage fium Lye viewpoint oi operstirg eccnomy is that any seri-ous Cer'sct in the hearth makes it necusar] to q i a c e the entire 5ear?S, wh i c i is 50thexpcwive and ti ne ansumirq. To get mu n d this Ciretv&n*Zq5 it would 5e ':e'.?er todesip tAe h e m s 'aseveral 9 C . s so tkat ?arts that are eesiiy damaged cm be ?movedand repiaced. 73is is one of the LYoqh ts kehind tke V + e c h , Cesiged by 11. BIorncuistof tke Swedbh Generator Gas Co., which w as installed toward t2e 2nd of :.?e war inexistirq ggner3tars to replac3 wonout original h e a r t h s .In its simplest design, tYe V+emfr (set r' ip re s 18 snd 7 : ) ccrrsists o i a he=+:: mantlewelded :oge?.'ler of two truncated plate cones with the points direcred toward each ;the?,so that t9e 2oint of the lower cone gcqetrates that oi the upper csne, ;!us creatirq aring-~ha~edonduit in whic! a cast-ifin erg is lcosely ?laced. T3e he&c,'r nant!e was, nthe beqinnirg, made of 5-rr. aluminized Slack glatt with i t s qp e r edge welced onto t3enozzle r*bg of 'U'le generator. When the generator was ued, a protective : ve i l or' ash mdcnartoai ?aFticies was budt uo in a few xinut- around the imiCe of the heer:f! mantle.n i s imulaticn mil,,whi& ivas soon 9acked toqcther to a relatively solid mnsistenc:r and'AIM nainteined durirg ooeration, ?mtec?ed the herrc.3 mant!e from severe thenelstress. The only metal ?art nor s eqs ed . especially atou~dhe ooe!!inq, ts the heortkrirq. F.u the hearth Anq will inevitaoiy 5e suoject :o damega. ;Vhen c s r .pri:h '':or?alm e ' ' it !asts for 400 to j 0 0 houn o i Clivir!!&ring norr;la! P U oac. I t is veyr inesen-dve and may 3e regiaced without the use of t301S, iri z nirxte or SO whi le cleaninq :hegenerator; t',ereiore, the cost of reglact.ment'b of .to :izaortancc. The ;cod nest ccn-ductivity of :he ;;onalloyed cast ircn cantzibutes consider&& to :he :t!&'.ivo& gXZ?Cursbiiity of :he hear.> :im !us it rney 312 ebated :vi-,et?.~t l ! ~ ' 1 ' l i ~ ~s ~alzec',2y Tt&lu-fs cr ui rg t'.e :i~q of siloyeti matarid, ;vhicfi is rnore hest resisrant 2ut ~ossessas co:o,rheat cmcuc:ivit;r.


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Cost-lranCo3striction U g

Iron- Plate=earth XancLe

InsideIcsula i nby UnesCast-IronV-Searth,easi lyrmovaole

Ffg-~re 4 . V-Bearth o f Sheet Xetal vizh aCast Searth Ring of Yonalloped Lton PotIn s td la t io n Fa Geaerators o f Various Xakes..--In the desigm with a welded hearth mantle, there wes sometimes a tendency towarddesca l i q on t!!e inside of the lower cone of the hearth mantla, after extended heawdriving. To secare long life, the mantle was later manufactured of metal plate alloyedwith 6% chnme , end ftndly of cast steel with a 6% chrome content. In the latter casethe V+earth w e s supplemented with an upper part, consisting of a nozzle ring fitting theheartn, with a ft~nnel or disect connection to the lower end of the fuel store and withdimensions to fit the store. Such a hearth is virtually indestructable, apart f rom theeasily removable hearth r iq . Since hearth rings of various inner diameters may be ?utinto the hearth mantle, one and the same generator can eesilp, through rinq changes, beedjusted :o various hearth loads. (SeeChapter 6, Figure ll8.)Figure 76 shows a German generator for wood, pest, or brow+ coal, which, like theV-heartfi, h u a removable hearth ring. [71

Insulation of t3e Wood Gas GeneratorThe following may be added to the above views on the insulation of the wood gas genera-tor. A wood gas generator has a thermal efficiency of about 813%; i.e., a fifth of the heatvalue of the fuel is ion, partly through radiation, partly with heat physically bound in Lie

, generator gas. Efforts have been made to decrease these losses through various designs;e.g., '&ough insulation of the fuel storage to prevent heat radiation from the outsidewalls gf L?e generator, through leading the hot gas up around the fuel storqa between


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the o u t ~nd inner mantles, t!!ough ?reheating the primary air,etc. With t f e a c ~ g t i o nof the last method, however, these meanaH do not appear to be useiuL TSe reactionability of charcoal b impaired by v e q high cfiarrirq temperature and long c ! & i d m ein the generator, wh i c ! may be observed, for instance, in q4ra f t generaton. As men-tioned in Lye p h ~ e d i qecdon, i t may b e more advantageous to promote condensationand C&umidificstion through ext reme nol in g of t h e wa l b of t!e fael s torwe. As shownin Chapter 2, tor instance in the tesu by the Steam Heat Institute, it is the heat-cansuminq reduction zone of the generator that, by irmrlatfon, should b e prevented fmmunnecrsar2y emitting i t s heat. In keegirq the temperature Lfem as high u he dcsiqnand th e pmpcrtia of the heart3 materid permit , the velocity of the reduction pmctss 3increased u s the heat value of the @is at a given gns vslocity. Experimental tests haveshown chat :he reduction p r o cm in normal gen erat on may be considered comoleted a t atamperatme o i agpmxirnateiy 8SGC to 90PC. To maintain th e gas quality, the gasshould be cooled fairly wrapdy La., immediately after leavbq the hearth the gar thouidbe conducted out of the m e r a t o r via the shortest path, and cooled down ("ftozcn inequilibrium") o prevent the dccomgasi tfon of CO to C02 and camon.

Fl3ura 7 5 . '3.c Gca t a t a r f a r Zood, 3 r - l ~Coal, a ~ d eat, ;ri:kou: O u t r t C:ar:aaL 3eC.

C. .:*re 73 B a p i c w e of a generator intended for wood sac!n w n nrl;m e :?- showsthat the i n c l m i q ) r : m uy air is mnchcred 7 .n the heanly imulated best!! and Cat thee m i c e d p p e s out 3etwnn i f e oute r wal l of the generator and th e air intake. a h i c l 3arrac.q?d ' concenr;icUy m u n d me be-?. I!? this way, t:e gu 3 cxoled sf: and :>e; r i m ~ ir 2eated. Psfe~Lark~n s t ac io w ? g9ne mton *where cer. 3 ao farced airovazaaie for ccoiFrig :>e glnerator ;a. ich ~9oLirq3y inconiq li? 3 of g % s r


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advantag?. The picture also shows that the outer charcoal 3ed has been con?lettly:enoved, E I I ~ he generator fue! is carried directly by a grate. It has been eeterzinec:hat no reducticn takes place outsida the lower e63e of the hearth; on the other h a d ,there is a risk of recreation of carbon dioxide and free charcoal in an outer bet, wh i c l iswhy such a desigx is suitable from this point of view.To ?mtect the hearth material and further improve the local hearth insulation, ash-k5eping hear th designs are highly advantageous. The V+earth tw uch a design, as doesthe Zeuch 52s genereror shown in Figure 76. These designs &o have easily removablehearth rings, whereby the specific hearth load of the generator may easily be adjustedwithin certain Limits for various operating conditions.

Figure 76 . Zeu& Wood Gas Generacer ~JithRenovable Casr-Iron Heart5 Ung.

Hearth LoadThe con cq t of hearth lcad plays a very important role in dimeruionvg a wood gas gener-ator kearth. The hearth load is the quantity of prepared generator gas, reduced to nor -rnal cubic rnetcn per hour, divided by the smallest pasage area in cm2 of the hearth(?lrn3/crn2~).hus me hearth load b dtrnensionrlly a velocity although it is customarilye ~ z e s s e d s a nurxrator and a denominator. The hea r t h load e ~ r e s s e dn :his way iscslled Bh and the imaginary velocity of the prepared gas, in its normal state, through Lyesmallest ?assage area of the hearth vh (m/s). The following relations are obtained fromthe definition of the hearth load.

P~acticdly, he !oad range for aU wood gas generators is fairly narrow between an ucperLimit a hm u ebove which :he gas quality is made poorer due to charcoal dusting in thecombustron zone, and a lower limit Bh sin, below which th e ges, due to too low a


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t empers tue in :he heeih cr in cer:zin p a r 3 o i i t , w i l l ccntain unaccs?tzbt: i-5 cgan-tities of tar . The rehtation 3 e tr e e n mL. m d ah niq,hich csu ld 3e cnC& :kc flex i-bllity of t9e genera tor , is of g rea t im oo nan ce in op er st lo n with :viCe!y vary.;;nq lcad (e.q.,car operstion). A s p e a t a f lexibi li ty as ;ossitle is desirsole in such a cue, a d henumericsl vallde of the .?exibility 5ecornes, :o a certa in e s e n t , an ocerstinq qualityparameter .In Imbert wocd gss g l n e r a t o n and other s imilgi t.;pcs, :he 3h,, reaches about 0.3 incontinuous operaticn and :he Bh min Sa y s within a xnga o i 0.3 :o 0.35. This q v e s af ledoi l i ty be tween 2.5 and 3.0. Tests on Vi.lesrths have given pracdcdy :he jame va l -ues or may9 :vheraas a h n in has been iess :han 0.2. An eight-hour test :vi:,L, 33 = 0 . 3 3on a Virearth wood gas genera tor i r o n t h e S w e d b h G e n e r ~ t o rG s CO. (;vith P Ses t -imulated lower part) Curing operston of a 2 ~ c l engne , has been carried cut .zrithouiabnormal tar content in :he gas. The V+earth has thus given th e ger.era+.9rsa : lax:bdirjof at I em 4. 3 8s oboosed to the maximum value of 3.0 for a hesr th designed ;vith ineta lonly. For the te st with Bh = 0.05, a flexibility of 18.0 was obtained, which 3 a unicuevalue.I t is gcs s ib le io a rxbu te the ve ry good idlirq ?ra pe rti es of the 'J+earrh sxc!uiv ely tothe good heat insulation of the mnbustfon zone, but there is s t U one oti'ler fa ctorinvolved. The ssh mantle, wnich is cuntinuousl!? re cr sa ta d, es c n d s :o :he sam e heig ht asthe nozzle openings, ma crea tes be twee: thes r ooenirqs lo c d " i,Wat:on cQs hicr s" n th e5 e s n h , #hose pauaqc c ~ s s - s c c t i o n hu s b ec om es, es it were, an "a-gon" ::vi:ere n is :3enumber of nozzles).' TSus, th e cre eti on of -01 zon es be ty ee n :be ~ozt!es is ~ r e v e r . t e d .and th is s a on s to m nt r i iu te cons ide rab l:~ o t h e fact hat no :as e s c q e s t kr cu g? ::ehearch even a t a very low load.T3e pea t adaotabili ty of the generator is a v e q i m u or ta nt p m p e r t y ::ern an ? c z n c n i cviewpoint, ;articgular!y during in terz i tzant cs r opera t ion and Curirg gene re tz r SES s c e r -ation of fi shirq boats. which sometim es m ust ;%m ain for hours :vith ;ke z o t c r Icli7.g.Only with a '{+earth h a s idlirg, in the strict sense, bccsme ?ossiole in wcod 32s opera-tion without decrease of th e continuow maximum 2ower. T3us, :vood g- c ~ e r z c i c nv iL !widely v a r y i q load may b e said to have W en a ra th e r m e tag :'cr:vard.

Devices for Pr imerr .Air DeiiverrAs mentioned in the introduction, in a few czses grirnary air hes beer. Celiverw! ;'?dmabove through a cen t ra l air nozzie. T3b nethod, however, h a . a cenCer.c:r to czuse hzr.3-irq of L?e :vocd around the air gipe and the nozzle. TSere have 3eer. a :'?!lixco? t :~ rswhere the gr imary zir has 3een fed nto t3 e como usd on zone f n m >e!cw t:r3ugn 2 ?er,-34 ?ioe iunninq t2rcugn the h e s t * t 2 e ? io e S c=pped Sy z cozzie part :vitfi 3 cicsed to:,end and q ui pp ed .~ it ,f numoer of :sai d nozzle holes. T>e ooject of :his ceirice : v u to? r e he a t t h e a i r i nt m se ly ; ~ 7 erinc:?le of is ? rcc rdure 3, however, incgr?acz, !r. :kat:3e heat b taken i,icrn t h e h e e t l ~ s n s u m i r g ~ d u c t i o n cn e.in most wood gas , -weraton ;he 2rirnllry air 5 fed in :hrguqfi a :in3 c i r . o z z l ~ . i l e d yd3:::Butsd over :e e r i r rh ew a t or immeciatel!: i e i cw te lower ooening o i :>e c5arri:giunne!. w,d dire=:cd .-zdi&y inwud toward :he t . , e s t f i axis (f ~ ) ~ r e s2 - 7 $ 1 . T>K i:;s;err.s ?,rcceoly ~ c s ;ui:aoie. -4s or ccnduc:ir.g :>a ii: :':on ;he ?r?zz.-_r21; ;r,c?.ue :o :3e


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nozzles, various soiutions have been tried. In an Imbert generator the intake loads to ec$t?iSu:icn chamjer, frcm which air p i p s , bent in en arch around the hearth, run indi-vidually to each nozzle exc?gt for one which is directly connected to the distributionchamber. This method is hardly ideal; the air is not evenly heated and distrbuteb. :Veld-ing a distribution mantle onto the outsids of the hearth either with one air intake :hrou$hthe generztor case or with two opposite intakes, has also been tried. I t has been difficultin practice to prevent cracking, due to thermal stress, in this design. A third method hasbeen tried experirne~tally n connection with a V-hearth: air intake, distribution ring,and heer th mantle were all cast in one piece. T h b design gave good results but is rela-tively heavy. .4U the 5ysterr.s mentioned take more or less heat frcm the hearth, which isincgcect i n princi?le. In the last mentioned design, however, the quantity of heat car-ried of f 3 eirly insignificant. Preheating of the air is not sufficiently effective in anyof the ::Tes mentioned. This could be improved by pasting the primary air through aheat cxcnsrigar Seiore the intake.Fiq~re 9 shows a design for primary air delivery used in one of the stationary geneFatonof the Swedish Generator Gas Co., made so that parts may be replaced without weldirg.The air intake is placd at the top of the generator and opens out into an u?per distribu-tion r i q , from which four primary-air pipes, evenly distributed around the peri~hery , odownward near the inside of the generator to a nozzle ring, which is su?pofied by a ring- 'shaped shoulder on the inner mantle. The lower half of the fuel storage is doublejacketed. The emitted gas flows through the ring space, which results in a certainamount of heat insulation. In the upper par t of the generator is a ring-shapedccndersation-water pocket which &ai r s to an outside collector.The upper distribution ring stimulates the condensation of water vapor derived from thewood. Xo dangerous thermal stress occurs in the air-feed- devices, and the ?eripheralprircq-air pipes promote practically no hanging of the wood in the fuel container. Onedisadvantage is that the design is relatively heavy an& therefore, suitable only for sta-tionary or marine puqosss.There is r.0 solid, scientifically documented S& for the choice of the most suitablenumber, diameter, and placement of the nozzles. Unfortunately, a systematic investiga-ticn of these questions has been neglected and in t h e practical design one has had to tryto apply, at random, certain findings from experience. The operational results of genera-ton designed in this way have been satisfactory in many ways, which seems to indicatethat the range for the b u t device does not have namwly drawn limits. This is veryfortunate, because a narrow optimal range would crstainly involve a very high sensitivityof the generator to variations in load, moisture of th e wood, etc.

Total Nozzle AresThe relation between the total nozde area (A,) and the smdlest passqe ares of thehearth ( A h ) varies in generators with good operational properties within very wide limits,between about 3% and 14%. I t is customary to use high values for this ratio for smallhearth diameters and low values for w e nes. T U rocedure 3 besed on the ooinionthat there should be a greater air velocity in the nozzles of large he=ths, and thengreater 2enecati rq ability of the air streams towards the hearth center. Whether thechange of air veiocit~t in th is way is really desirable or necessary h a s never Seen


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satisfactor ily investigsted, but o r Lye time being is mereiy an unoroven assu npticn . Inreality, t.clis ?ruc&ure may be seen as a result or ' L9e simoie and inevers .ve method ofusirg L?e same cozz le devirx for several grearly different heart? diameters.The Inbert generatom, which wer? used during :he wa r in v e y Feat numbers and which,on the whole, had v e q good grcperties, used :!7e nozz!e devices shown in T m i e 25 . inTable 2 S correqondirg data for the Swedish G a Generztor Co.3 SGB 600 ncde! ger.e.ce-tor, with a V + e m h , ere g v e n .

5 5 C / 1 7 and j30/;!

?AS( far c a t s ) 80LOO130


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Hearth Diameter d;-- uTiguro 1 1 . Graph rncvfng the Se la tLo r r betyeen eke TotalXozz i s hrsa and th: S a L l e s t 3ear,h Ser:icn, .U: Veloci:7,etc., as a ?unc:ion of Hearth Dia=eter a t a Searzh Loadof 0.9 %3/calhr.

p c t i c s l operation that, for such two-qcfe operation, a ccnsicerably lcwer air ~:e!ocitythan in fourccyde operation may be used without impairing combustion.The great variation shown in tCIe graph, of V with the hearth diameter of Imoer: t;qegenerators, could probably be reduced considerabiy. Table 27 , drawn up on t3e basis of aproposal fnrn Hesselrnan Motor Corporation L:d.. bears upon nozzle devic5s for Imbertgenerators and is c5aracterized by an even, moderate increase of the air ve!ociQ~ in :henouies with the hesrth diameter.T3e values of the two columns :o the right in Table 2: &re shown in the r s o n of ?Ig?xe78 . The values xessured tor the system evidefltly differ irsigniiicsntlp f m n :he contin-uous cyrve.Tl;e nczzle devices of this system ere suitable Scr an Irn=ort. t p e wood gw ;;er.erstorwith an original hesrth, which is used for operat irg four-cyc!e engines ;vith rnany cplin-des . Such genextors have been tes:ed in operation where the original 5e~,n,has beenre?iaced 3y s V-kesth; good :esuits have been obtained without changirq :.?e ;lozzles;thus a cime?sioninq sirnil= t o that shown in :>e teble S certeinly elso suitable fo r'I+ear:,'ls curirq cceraticn of foumjcle e~qinesvita several cylinders.


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MO- 125


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T a b l t 2 7 . S C I T U - 2 NOZTZS FOR =OD GAS GZE-UTORS T O 3 FOvrc -Cc t cENCI,N'&S KIT3 SIZB.4L CP-IXDEBS--;il';YiX PAAZh iESESSU I TULZ V . - C J J S FOP. OPE -UXSG S L OW TiO-CYC2 2!1GI,s(ZS

dh - Diaaeter of the hearth c o a s t r i c t i o n% - Area of the h e a r t h coascrtc:ioaT o t a l nozzle areav - 'Theoretical" air va loc i tp in t henorzlaj duj2.q a hea r th load of

0.9 ?ha /c=r hr


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MISSOURI DEPARTMENT OF NATURAL RESOIJRCES - OIVISION OF EPIERGY CONVERSION TO ENGLISH UN

I 9 8 / Z inchesHearth Diar re te r dh

s

Figure 78. Graph of Suitable Nozzles for Operating Four-Cycle Engines with Several Cyl inders.(Extracted from Figure 78, pg. 127, ~wedi;h en-Gas Book)mm converted t o inches on the horizontal scaleThe ra t i o . 100 corresponds to column four , Table 27 ,page 126.

MO- 127


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Sirnil&-&, in FIgvye 80 there is e dotted scde ~1abora:eC for Lie relation Setwee? t k eheight above the ,'iesr'.> corstxction of the nozzle plane (h ) and the diameter in thehe&-t-th cops:.-uctio:: idh). -4me%? curye is also drawn for this.

loo I& too 2i'7 & mn,. esrehan ? l o t o r DLanerer0 SGE 8COA SGB 600

Zfgure 80. B e i g h t or' the Bozzle Plane above theSeatt5 Constric=ion for Various Generator Sizes. .

Both these liqrams are based upon generators of the Imbert type, If, fmm the twomean curves, *e voiume of t9e effective combustion space is calexlated, con s i s t t r of a2tnncs:ed cone wim the height h a d he areas 7dZrP4 and nd h:49 rq ec tive ly , of thetwo parallel surfaces, md if this volume is divided by the gas volume produced at e cer-tain heanth :cad, tSe result for the entire generator family wil l be a time constant,If, for ins:s-.ce, the generally a+nrmedmaximum hearth loaZ of 0.9 im3/cm2hr is chosento be tne Cencni.?ator, the result of the division determined by the mean curves w i l l be0 3 econd for all generators. This time h caldated, however, on the assumption thatthe spac? in question does not contain any solid substances and that the temoerature isPC. If, for example, it is assumed that charcoal takes up 0.6 of the total volume and thegas then 0.4, and that the temperature is 1200 '~~he r e d time will be merely approxi-mately 0.01 s. Consequently, this means that the dwell time of the gases in the ?aceabove the h em 5 construction is 0.01 sTo date, no generd rule for diinensioning of t i e hearth has been given in th e specialistliterature. The dinensioning system pu t forth here-with the mean curies in F b r e s 79and 80 as beses-is intended to make up for this lack. The system is based on an ernpiri-cal foundation and gives satisfactory results. That does not mean, however, that ahearth with dimensions differing from t i e system must be, or probably wi l l be. a ?oarhearth. On the concary, the system appean to allow for fairly sipficant deviationswithout obviously wdavorable corsequences; it does seem, however, that :he ratio h/dhshould not be made greater than as shown in the mean cu.ve of F i v e 80.


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F i g . 80 - pg. 128 'rm t h e Swedish Gen-Gas Book convers ionf r o m m e t r i c u n i t s :I e n g l i s h u n i t s .

MO- 128


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T , e pc or' the he+-h be!ow the n ac o w es t sec tio n should be mace a t;.~ncsredccsne.with heig9t d:, and :he opening di am et er ? .5 dh. TSe incressed gassage arzs iownwarc! 3intended to csuse a cansiderable gss veiccity decrasse, and t5ereSy an incresse of thet ime tha t t5e 3 spends in the presence or' chsrcaai at a t e m p e r a t u r e h i g e r t5eqacpruxinate ly 800C. T3is is adv ant q-u s fo r ?rc;duc:rq ma ~ir num educdon. O n 'c?.eother hmd, Lye eq an si on n u t not be so p e a t ' h a t t h e te m p er at ur e a t t he ope l i ng goesbelow abcut 8004C, since the lower tem pera ture to some ex tm t seems to s timula te sr e l c r a a t i o n o f COZ. T3 e n or n s given ab ove for dimensioning ar e x!ues ..vhic.i havegiven good ;esults f.nn e -qe r ienc t .Due to the considerde Crop in ternperaturs, prsctically no .-eduction teks ?lace oursidet3 e hear.3 (see Chaoter 2). Due to this fact, it is fu im po rta nt whether :he j jace jelow3ie hea r th openkg 3 illed with a bed of charcsal ar spme ocher pomus xatarial (e.g.,porous co nc re te ) or ;vhet!!er it is f i i e d with any rnate*al at ail. In przc t i cd ly all woodgas generatom in Sweden a bed of cha rco al or porous conc rete , restir,- on a shakirq,grate, b placed a t aporox im a tdy the dis tance d 3 below the hearth ooening znd apprcxi -mateiy 0.5 d above the bottom of the generator. The qac- above and below this so-tsare made accessible from the outside by a relatively laqe ash pon . It is vitzl for properooeration of the generator t3at this port be t ightly sealed.? c a t Gas Ge~.e ro , tonS o special genera ter ccim fo r pea t gas oper stion ;verb ?rsduced in Sweden I.~ri.ywar. 13 practi cal test s which were cmied out on gene ra to r gzs cpera t icn wi ih ?cot. ? e a tcharmal , or pes t coke (br iquet tes ) ES fuel, rqliar ges sen erat ors for c:?er=cel c r wccdwere us&. Various operational d5tuFSances were quite common due :a :ar m d s l q!maation. The main reason for the inferior results was tha t t5e ?eat used was of w u i t -able quality with tco p e a t ash cantent , and the t e s x zeen :a indicate t?at a satisfac:orrgenera tor gu operstion with pest as a fuel is not tossible if th e a h m n t e n t cf -,'le s e a ts iqnrf icst !? exceeds gp m xi m at e l p 2%. In addition, the fuel nust be :e!ati.~eLy freef m m 2 e s t Curt, ch a rc ad Cust, and foreign substancs.Judqrg from tests csrried out 3y government authori t ies in Germany lurirq the war, i tappears tha t pest with low ash content could give sa t is fac tory ocera t ion in ~ o o d ag en er at o n gruvideci th at LFte c i a m e t e n or' Lye primary* :.oztles are tncrbssad so nuc3(on the order of j O % i t h a t t h e t e n p e r a t u r e in the cornhustfon zone w i l l stay below :>ef.xsinq goint of t!!e ashes. ~ o o r o x i r n a t e i y 250aC. This t e s t w a s csrr ied out in ul ImbertTeneratcr wit!? t3e smal les t hearth diamete r a t 130 mm and w i th r'lve stw.eer< 2-m ai r .nozzles. The gst cleaning spscem was the,usual one :vttS :vet c!e.ane?s ar.d ccr!; ciesners:the cooler was a sta nd ar d t p e with 117 ;no cooi i rg SUT~PCO.T ~ Kp anerstor :vas Iint run for :*NO hours on an O o e l 3 E t z ?:ck whosa n o to r had a3.j4 q!ir,cer volume an d a 54470 engine d eveio airq ?ezk eificis ncy on 3zsoUze zt 3430Fm . T a e ? e a t s i z e was 4040 n m end the wa te r c sn te z t c i ? ? e ? e s t 30% i o 33%. :Vi:.l:>e l2-mn nozz!es inte nd ed fo r wood. t ' e hear:,'l r o r n ? e r = r x e j e c s n e vey: 3 q . i iover1400~C)t ~i..:c.i 3 e ? e s t c s k a i o t z t a t i o n b e c s n e : c o i ~ a l l d :ke ccke b u r s t inrotieces. 3 y I ~ c r ~ a s i n q e nozz le C iane re r to 10 n n :.uimlicn Invoived a :o~verir,q q i :eternperztuFe in t5e cgrnSusiicn zcne to !1008C) 3 e s e c isa t' lantages :vers ??z:r,ar:d:2Cce---i.-..q :a :e :o?o rs :3e g ~ n e r s t o r - e nc er ei 3 :sc::c=L:: :ar-r'.-eo 5s. c :...e


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peat-coke formation was so good that no charcoal had to be fe d into the reduction zonethrough the ports, even during extended operation. The composition of th e gas was aboutthe same as i n wood operation. The se rie s of tes ts w a s completed with long distancetests with a 3.5-ton Mwrus tmck, equipped with a 7 . 4 4 diesel motor with 9 0 - h ~ eakefficiency during oil operation. The peat consumption wi th a 3-ton load on the truck wasapproximately 10 kgA0km. The operational properties of the truck when using peat gasproved to be good throughout, and the maintenance requirement was, on the whole, thesame as in wood gas operation. The gas cooler ha d to be flushed every 1000 km and thegrate shaken each morning in order to remove dust and ashes from he reduction cham-ber. P ~ t i , d a r ly in te rest ing is the information that, during the tests (which includedhighway driving: Col ogn t H am b u ~ L u b e c k - 8c r L i n ) ~o slag formation was obsaaed inthe generator. Pea t fue l with an ash content of @proximately 2% and 20% to 25% mois-ture was used.Unfortunately, no tests have been made in Sweden with a similarly reduced tem peraturein the hearth, and theref ore slag formation hes not been overcome. In exceptional cases,where peat coke very low in ash was wed as fuel in charcoal gas generators, the slagformation was so insignificant (somewhat more than 1%of the coke weqht) that satisfa-tory continuous operation could be maintained.Figure 75 shows a generator intended for peat, and the generator in Figure 76 is alsosuitabie for this fuel.


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A. Charcoal gasapparatus for movehicle.

B . Wood gasapparatus for motor - -vehicle .

C. Wood gasapparatns f r. 2 - ~ 7 ~ 1 2g d Z i ~ i lbulb motor wi thpulsator f o r boat.

IJ. Wood gasapparatus vizhcloth cleanerand pr eh e a t i n g o fgas for motorvehicle.

Figure 89. Schematics of Generator Gas Devices.


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Pigum 117 . spare Parts forfor m Lmbert-Type Wood GasW ara tor.A. Hurth cone of a l l o y e dc u t s tee l .B. Hurth cone w i t h airIntake and charring cane .to be connected to theh e r mantle.C. Co~nplete nner mantlewith hearth and air intaka.

CFigure U8. Wood Gas Hearthwith Replaceable Hearth Ringmd Automatic Ash Insulation(VoHearth).A. Changing the hearth ring.B. Caplice hearth vLthp r h a r y air fatake a d ahuth ring placed inside.C. EIearth ring (cast iron).


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Table 32 , taken from a gas generator catalogue fo r Scania-Vabis, 1942, shows t h e sizes ofgas generaton on the market for the various engine types of th e car manufactures.T a b l e 32, Z?LE SIZE Or GAS G-EUiORS i02 VAarOUS m Z S OF EscrEs

C.meraeoc WeL %*lgnacion)(rri.urr CUtoMl a.*racer 'UGu

tlOI Qilader Crltn&r G m %.dadUzm r p * t l r . c * &r urn b e t* taco. CO. b~~

- . toc.Ul b 110 X 136 5.17 M 40 5-3 - 3 f3/50 30/13 1304 3001 1701b U 6 110 X 136 7.73 7s 130 S-7 go? 1 551 15 LJO/550117011&1 b 110 X 136 7.75 7 s 114 l-I Z-7 1 55 Il J LJO/550/ 17060 1 6 110 L I36 7.73 7s 130 + I K I N I S 55/U lJO/3SO/l?O40 1 4 110 X 136 10.34 100 180 S-4 X-4 - - 17W6M/210-arm: rr r h a 8 7 L a . 170 s m a s mccioa 8bDuLd be4 ~ K a d t 120 o, cross mu .

Table 33 lists smaller types of wood gas generaton for passenger cars, etc.

CInerator SireOucmr Diaastar a t Air Xntak Bore Diammccr of the Hearth

As indicated by the type designations in Tables 31 to 33, the outer diameter of the gener-ator at the air intake, the diameter o f the hea r th for Lye gas flow thmughw.d sometimesthe total height of the generator were usually Usted, The fuel storage areas of the gen-e r a t o n var ied considerably in shape and size, degendinq uoon how they were bu i l t andwhat the optrational needs were.I t is interestirq that the number of hearth sizes Listed in the tables increcsed more andmore with eqcr i cncs , so that in the end t h e e was a c5oice of a series fmm 53 m m up to210 mm, ?witha 5- to IO-mrn increment for the various d i m e t e n for the wrnmon sizes(400, 4 5 0 , 500, jJO, 630 and ?SO mm ) of wood gas generators intended for e.qines from20 to 100 hp. In many cases tbere was some overfsppirg of hearth sizes fcr two closegenerator sizes. A 3001nrn generator, Cor inttanct, a u l d have hezrths up to 140 andI SO -mm bore diameter; a 5539nm generator, hearths down to 130 and 140 mrn diameter..These adaptations we r e attained empirically and they were never tested t!ie?reticdy.The nature of tie Pde! w i t 5 regard to charcod fcrmati6n an d v e t y intermittent ooeratirgconditions could 3e of inportar,ce here.


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When the gas generator is adapted to the engine's gas requirement, it should be notedthat the gas reqairemenr iacreses up to 70% if a supercharger is installed on the engine.Adaatation of the Ges Generator to Various Enzine Installations and UsesHow the gas generator is built in is frequently determined from case to case. In thischapter, the installation itself is not discussed (see Chapter 8); it should be done compe-tentti and in accordance with safety regulations. In this section, adaptation of the gasgeneretor refers to its design, wit9 regard to the ways in which a certain engine or wholeseries of similar engines =e used end irstalled. For instance, weight, space, air resis-tance, and aesthetic conside~ations re of importance in desiving the gas ganerator forautomobiles; for tractors, boats and stationary engines, etc., certain technical require -ments must be met.

Automobiles and Rai l VehiclesThe adaptation of the gas generator to automotive operation is a complicated and diffi-cult matter. So matter how competently a gas generator is irstalled in a car, it involvesconsiderable interference with the initial overall design. Therefore in the-beghhg ofthe generator gas epoch, to simplify installation the complete gas generator was usuallyinstalled on trailers; in this way, only minimal changes had to be made to the car. Fi

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