Small Scale Gas Producer Engine Systems

  • View

  • Download

Embed Size (px)

Text of Small Scale Gas Producer Engine Systems

Albrecht Kaupp/John R. Goss

Small Scale Gas ProducerEngine Systems


Deutsches Zentrum fir Entwicklungstechnologien - GATE Deutsches Zentrum ffir Intwicklungstechnologien GATE - stands for German Appro priate Technology Exchange. It was founded in 1978 as a special devision of the Deutsche Gesellschaft ffir Technische Zusammenarbeit (GTZ) G mb H. GATE is a centre for the dissemination and promotion of appropriate technologies for developing countries. GATE defines ,,Appropriate technotlogics" as those which are suita ble ai1d acceptable in tile light of economic, social and cultural crileria. They should contributC to socio-Cconomic development whilst ensuring optimal utilization of resou rces and minimal detriment to the environmcnt. Depending on the case at hand a traditional, intermediate or iiighly-devcloped car, be the ,appropriate" one. GATE focussCs its work on three key areas: -- Technoloinu E.whange: Collecting, processing and disseminating information on technolo gies appropriate to the needs of the developing countrics: ascertaining the technological rcqu irements o"Third World couintries: support in the form of' personnel, material and equipment to promote the development and adaptation of technologies for developing coutn tries. -- RescarclI and Developmen.: Conductinlg and;'or promoting research and development work in appropriate tLL:uologiCs. - ('oopertation in Technlogical Declolmnt': ICooperation in tile form of Joint projects with relevant institutions in dCveloping couniitries and in tlie Federal Republic of Gernialny. For se *;'al years GATE has been an active supporter of tle SATIS network (Socially Appro priate Tecunology Informiatior Services) and fis entered into cooperation arcemclts with a number of technology centrcs in Third World countries. iATE offers a f'ree information service oil appropriate techlnii oflogies for all public and piivael development institutions in developing countries, dealing with tile development, adaptation. introduction and appliCation of tchnologiCs. Deutsche Gesellschaft fuir Tcchnische Zusamnlenarbeit (G'TZ) GmnbH The government-owned GTZ operates in tle field of Tech nical Coopcration. 2200 German experts are working together witli partners from11a o1 I10 countries of Africa, Asia and Latin America in projects covering practically every sector of ageriCnl ttr.C, forestry, economic development, social services and institutional and material inf'rastructure. The GTZ is commissioned to do this work hoti by the (overnment of the Federal Republic o (ierna ny and by other governnent or seli-government ant lioritics. The GTZ activities encompass: appraisal. techl'ical planning, control an1d supCrvisiol of technical cvooeration projects commissioned by the (iovernmen of the lFCderal Republic or by otcr authorities providing an advisory service to other agencies also working on developricn projects [lie recruitment. selection, bricl-ig, assignment, admiiistration of' expert personnel and their velfare and tcchnical backstopping duIiring theii period of assignment - provision of llmterials and eqfipinen t for projects. planiiilng work, selecliou, purchasing u and shipnent to tile developing coni,trics management of all financial obligations to the partner-country. Deutschcs Zentrum 'ir tnlwicklhngsiechnologien (lATF in: Dct schc Gesellschafi ffir Technischc Zusammenarheit (GTZ) GniblI Postbox 5180 D-6236 Eschborn IFederal Republic of' Germany

Tel.: (061 961 79-0

Telex: 4 1523-0 gtz d


Albrecht Kaupp/John R. Goss

Small Scale Gas ProducerEngine Systems

A Publication of Deutsches ZCetrtim ffir Entwicklungstechnologien - GATEin: Deutsche Gesel schaft fir Tech nische ZtLsammenarbeit (GTZ) GmbH

Friedr. Vieweg & Sohn


been working in the fields of civil engineering, nmthenlat cs, and hiomss encrg) conversion systems since 1972. Now project officer 1or biomass .erg,,, coniversion systems since 1983. His field of.expertise is gasificalion of biomass. John R. (Goss. N1. S.. Professor at the Department of Agrienlutural Engineering of the Uni versity of' Catlil'ornia. Davis. Mayor fields of research have been harvesting of, agricultural crops. forestry. and gasifiCation of agricmltural residues.

Tie' Auhiol r.: Albrecht Kaupp. Phi.). staff' memb,

of GTZiGATE has

CIP-Kur;iicla iifnalim

der I)eutschen Iiblioliek

K-wiplp, A\lbrechl: Small scale i, producer cniimle ,\sicls : a phl. of, D1. /Cnilrtm f~ii-himtwicklung,,lechnol,.intl ( ,\+11 i: IDt. (;C,. f'61 Cll]h. ZU ,M11HI~lcTMhit ((~l'~ (IT/-61M A~hrwdhl Kaupl- .hin R. ( io>,,. Ihimm,,clmcitz,

IShN 3-52s-I2(C i INF: (Goss. John ,..

All rigls rcser, ed.PuIbliSCLI

.)eulische (icsclischaft fibr 'Ic01icie Z1iurmneirhei t(.1ic

( uimbl I. Eschborn 19,4

h\ IriCdr. V\iOcWc & ."ohn Verlag,cscllsdtaifl mbll. Btraunlschweig Priliicd in ie Icdeil IRkepublic )I'( icili\ 1,\ ;-engc|icher I handtI:;druckerei l.engelich

ISBN 3-528-02001--6


This monograph was prepared for the Agency for International Development, Washington I). C. 20523. The authors gmteflully acknowledge tile assistance of the tollowing Research Assistants in the Department of' Agricultural Engcineering: G. Lamorey. Li. A. Osman and K. Sachs. J. L. Bul11u'ener, 1)ra tsman for the )epa rt ment, did most of tlhc ink drawings. The writing of' the monograph provided an tniquc opportuity to collCfe and studv a significant part of the -nOWish a nd some (ierna itera lturetlm on the subject starting about the year 1900. It may be conuftIded Ihat, despite rene\ed worldw\ide efforts in this field, only in signiticant uadvaices have Wen made in the design of' gas producer-engi lie systems. Esch born. Ielbruarv 13. 19S4 Albrecht Kaupp


Chapter 1: Chapter 1: Chapter III: Chapter IV: Chapter V: Chapter VI: Chapter VII: Chapter VIII: Legend

Introduction and Summary History of Small Gas Producer Engine Systems Chemistry of Gasification Gas Producers Fuel Conditioning of Producer Gas Internal Combustion Engines economics

1 8 25 46 100 142 226 268 277



Gasification of coal and biomass can be considered to be a century old technology. Besides gasoline and diesel oil, producer gas has been used to drive internal combustion engines almost since their invention. The generation of producer gas from wood and coal has been reliable and inexpensive compared to the use of gasoline and diesel oil for a long time but was generally only accepted during emergencies and war times. Although more than one reason accounts for this phenomena, the most significant factor has been the inconvenience and the required skill necessary to operate a gas producer-engine system. The recent interest in gas producers has somehow diverted the attention away from the real problem of gasification. A gas producer itself is of little use. Gasification must be clearly seen as a whole system consisting of tie gasification unit, the purification system and the final energy converter such a, burner or ; internal combustion engine. The real difficulties are not so much to obtain a combustible gas, but to genc.,ate it in a physical and chemical state necessary for long-term internal combustion engine operation. Gasoline and diesel engines draw their fuel from t tank by natural suction or forced injection. These fuels are homogenous and do not change composition or physical properties over many -ionths. It is therefore sufficient just to turn a key and start the engine. A gas producer driven power unit requires much more care and understanding. The gas producer grnerates the combustible gases as demanded by the engine with no storage container between the engine and the gas producing plant. Physical and chemical properties of the gas such as energy content, gas composition and impurities will vary widely, even within a few minutes or seconds. Their control is limited by the vey nature of gasification, a complex sequence of partial combustion, distilltion rtnd reduction of lignocellhosic roiterial under high temperatures ai1d close to atnospheric pressure. The gas generated needs to be highly purified before it is use( in an engiine. The commerciaily available filter, condensing. and cooling components are not specifically designed to adequately andling thie wide range of requirement for the marv biomass fuels. In sumriimary, a gas producer engine systemi, wirether it is used for generating electricity, pa lping water or driving an iautoiobile must be custom tailored and the operator trm ined in the peculiarities of the system. No one would ever try to r11n a gasoline engile oh diesel or vice versa. The sime restriction applies to the gas ifyinrug uin of tile system. it It needs to be designed for a specific clniss of fuels. \'i-irtiois in tile puhysicll aid chemical conruposition of' the fuel are tolerable within limits. For instance, it fixed b J gais producer designed to gusify wood blocks of i spcifi( size iiunr moisture content will !(.t run as well or the same wood blocks with it munch higher roistur'e content and will cerse operution nil together if fueled with straw. The cl.irns sometimes found in papers arid 1111 ffacturers' brochures of gasifiers operating on almost every type of waste product containirg combustible carbon must be taken with extreme caution. Although a gas producer-engine system is built as a mnit arid fine tuned for a successful operartion, it is riot necessary to develop special engines. The existing internal combustion engines cin be us-d with little modifications. The ,,sually unavoidable power drop, due to the lower energy density of the producer gas-air

mixture is not a serious drawback. It can be recovered by turbocharging the engine or some other modificati