Development and Utilization Potential of Biomass

Gasification Technology in Eastern Africa Region

By

James M. Onchieku (PhD)

Bioenergy and Climate Change

Kenya Forestry Research Institute

P.O. Box 64636-00620, Nairobi

Email: jonchiekukefri@yahoo.com

EXECUTIVE CLIMATE CHANGE AND CARBON TRADING WORKSHOP held in

KENYA FORESTRY RESEARCH INSTITUTE, MUGUGA, 12th – 16th Nov. 2012

PRESENTATION OUTLINE

1. Overview of biomass gasification

technology and utilization

2. State of biomass gasification technology

in Kenya and its potential role in climate

change mitigation

3. Challenges and opportunities in BGT in

Kenya

4. Conclusions

5. Recommendations

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1.0 Overview of BGT&U

Gasification - Definition– Thermo-chemical process for conversion of

carbonaceous material (biomass) at elevatedtemperature in O2 deficient atmosphere(partial combustion) into its basic components

1. Combustible gas of carbon monoxide, hydrogenknown as “synthesis gas” or “syngas” and

2. Methane or producer gas or “towngas”; lesseramounts of carbon dioxide, water, and others.

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RATIONALE FOR BIOMASS GASIFICATION TECHNOLOGY

o Traditional wood-fires

– Associated with -ve impacts

• lack of convenience, emissions of smoke, carbon monoxide

and soot (black carbon) and forest degradation – Indoor Air

Pollution

• Improved technology as substitute for traditional sources of

energy

o Growing concern with global climate change

o Rapidly evolving RE technology over a short time-span

o Increasing energy demand and erratic prices12/11/2012 4

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Components of Biomass Gasification System

Gasifier applications•To fuel internal combustion (IC) engines for electric power generation,

irrigation, grain milling, sawing of timber etc – power gasifier

•To fuel external burners to produce heat for boilers, dryers, ovens, or kilns

- Heat gasifiers <1 MW

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• Gasification used as substitute to natural gas, as basic

chemical process for syngas production and subsequent

syngas conversion to other chemical products

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Biomass to Syngas Conversion pathways

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Producer gas constituents and hazards

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Updraft gas producer

Disadvantage: Excessive tar because air isintroduced into downward flowing packedbed or solid fuels and gas is drawn off atthe bottom

Lower overall efficiency and difficulties inhandling higher moisture and ash content

The time (20-30 minutes) needed to igniteand bring plant to working temperature withgood gas quality is shorter than updraft gasproducer

Preferred to updraft gasifier for IC engines.

Downdraft gas producer

Consists of two defined reaction zones. Drying, low-temperature carbonization, and cracking of gases occur in the upper zone, while permanent gasification of charcoal takes in lower zone. The gas temperature lies between 460 to 520oC. Total process takes place with under pressure of -30 mbar. Twin-fire gasifier produces fairly clean gas.

Disadvantages: High exit gas temperature, poor CO2 reduction and high gas velocityAsh bin, fire and reduction zone are separated. Design characteristics limit type of fuel for operation to low ash fuelsLoad following ability quite good due to conc. partial zones operating at temps. up to 2000oC. Start up time (5-10 minutes) is much faster than UD and DD units. Its higher temperature has effect on gasOperate well on dry air blast and dry fuel.

Has clearly defined zones for partialcombustion, reduction, andpyrolysis.Air introduced at bottom and act ascountercurrent to fuel flow. The gasis drawn at higher location.Achieves highest efficiency as thehot gas passes through fuel bed andleaves gasifier at low temperature.The sensible heat given by gas isused to preheat and dry fuel.Disadvantages: Excessive amountof tar in raw gas and poor loadingcapability. Hence it is not suitable forrunning vehicle.

Twin-fire gas producerCrossdraft gas producer

Types of Gas Producers (Gasifiers)

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Comparison of updraft and downdraft gasifiers

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GAS CLEANING AND COOLING

• Dust removal at temperature above tar dew point (app. 300°C)

• Tars removal at intermediate temperatures (above 100 ° C)

• Water removal at (30-60°C).

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• Gas cleaning and cooling is by a cyclone, a gas cooler with some scrubbing action and a packed bed filter.

• Gas cooling increases density of gas to maximize amount of gas entering engine cylinder.

• Wet scrubbers used to remove gaseous pollutants and solid particles;

• Packing bed scrubber consists of packing, liquid, support grates and distributors plates.

• Gas passed through bottom and removed at top.

• Fabric filter is for vehicle application; placed immediatelyafter cyclone.

• Filter with glass-fiber cloth can withstand gastemperature unpo 300oC.

• Filter performance depends on type of gasifier, fuelMC and how vehicle is driven.

• Recommended that gas flow ratethro’ filter boxshould not exceed 65m3/hr.

• Pressure loss over filter affected by load and amount

of dust in producer gas.

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1.1 Sustainable supply of suitable fuels

o Adequate quantities

oConsistency in quality

o Processing & packaging

o Accessibility

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Biomass fuels utilization pathways

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Suitability criteria for biomass fuels

Physico-chemical and thermal properties1. Moisture content - 8 to 20 % recommended

2. Energy content – HHV (gross energy) and LHV (Net energy)

3. Particle size and distribution – Determines rate of air and heat flow

4. Form of the fuel – Processing techniques

5. Bulk density - Ratio of weight over total volume; fuel density - available energy on weight basis, MJ/Kg

6. Volatile matter content - >70% (water, tar, oils, gases)

7. Ash content – Cause slugging and clinker formation; <5% best

8. Reactivity of fuel - Determines rate of reduction of carbon dioxide to carbon monoxide in the gasifier

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Some fuels and ash content

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Fuel Ash content

% weight

Fuel Ash content

% weight

Alfalfa seed

straw

6.0 peanut husks 0.9

Barley straw 10.3 Rice hulls 16-23

Charcoal 2-5 Safflower straw 6.0

Coffee hulls 1.3 Walnut shell 1.1

Coal 5-17 Wheat stalks 7.4

Cotton grin

thrash

17.2 Wood chips 0.1

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Some fuel properties

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2.0 The state of biomass gasification in

KenyaSome Facts• Energy sector policy and legal framework realigned to Vision 2030

and MDGs

• Energy sector vision

– Promote equitable access to quality energy services

– Promote development and use of alternative sources of energy

– Expand access of electricity to rural areas

– Design incentive packages

• 77% of the population are not connected to electricity

• Electricity demand:supply ratio = 1,191 MW: 1,429 MW

• Generation sources: hydro, diesel thermal, and geothermal plants

• Biomass based power ?? Co-generation?? Negligible

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Some Facts ... Contd

Favourable policy (2004) and legislation (2005)

– Import duty waiver and taxes onequipment

–Tax holidays for 10 years and dividendincomes from investments for 7 years

– Feed-in Tariffs policy (FiT) for capacities < 40 MW.US$8.0 cents per kWh

– FiT Policy provides for review every three

– Generation of electricity and transmission upto 3 MW without a license

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National Energy Mix

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34.3

48.5

1

12.9

1.70.3 1.2

51.2

13.2

0.9 1.80.4

31.4

1.1

0

10

20

30

40

50

60

Large Hydro

Small Hydro

Geothermal

Co-generation (biomass)Wind

Thermal (Fossil)

Off Grid (Fossil)

ENERGY TYPE

PE

RC

EN

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GE

% of installed capacity

% of effective capacity

Where is generation from biomass

Gasification technologies??

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Biomass energy resources in Kenya

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Forest wastes / residues Uses Sources

1. wastes 1. Poles/posts for horti-

and flori-cultural

farming

2. Fuelwood and charcoal

3. Fencing

1. Non- commercial

thinnings

2. Tops breakages,

branches

pruning

2. Factory wastes 1. Sawdust- poultry

farming

2. Organic fertiliser

3. Fencing material

1. Sawmills

2. Furniture and joinery

shops

Agricultural wastes / residues Uses Sources

1. Cereal-based

1. Wheat, Maize, Barley, and

Rice husks and straw

1. Hay for animals

2. Energy for boilers

3. Organic fertiliser

1. Large scale farmers

2. Peasant farmers

2. Temporary industrial crops

1. Pineapples, Sugarcane

baggasse, Cotton fibres

1. Woodfuel for boilers

and incinerators

2. Fuelwood

1. Small scale farmers

2. Commercial farmers

3. Permanent crop-based

1. Coffee, Sisal, Coconuts,

Wattle, Cashewnuts

1. As above 1. Commercial and small

scale farmers for fibres

and husks

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2.0.1 Stakeholder Analysis

1. Government of Kenya

– MOE (ERC, REA, KPLC, KETRACO, IPPs,

Energy Tribunal)

– KEFRI implementing 1 pilot project on

bioelectricity with support from Finnish Govt thro’

EEP and 1 project on micro-gasification for

domestic use and biochar generation for soil

amendment` with support from UNDP

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1. Partners – Ministry of Energy, Energen Africa International and

Multi Media University

2. Capacity building of various stakeholders to strengthen and

enhance their knowledge and understanding on Biomass

Gasification Technology and its Utilization

Complete Training Kit (TK) on BGT&U

Training of Stakeholders on BGT&U using value chain

approach

Workshop proceedings available

3. Comprehensive Database on Current and Potential Biomass

Fuels for Bioelectricity Generation

Based on physico-chemical properties and thermal properties

4. Develop model for sustainable biomass supply chain

5. Design, install and demonstrate performance of Modified

DownDraft Imbert Gasifier to stakeholders for upscaling and

commercialisation

KEFRI’s Pilot Project on Bioelectricity generation

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Improved clay stoves Biochar preparation

Mixing biochar for trialsMeasuring soil moisture

Plants amended with biochar

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KEFRI/MOE/UNDP’s Pilot Project on Micro-Gasification for

Domestic use and biochar production

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Project status – Show Training video

1. Training kit on micro-gasification for

power at household level and biochar

production

2. Trained at least 15 artisans on micro-

gasification technology

Practicals on making TLUD stoves and

testing the stoves on emissions and PM

3. Piloting and demonstrating performance

of the stoves in selected households Next

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Training artisans on TLUDs and Biochar

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Show more on video on lectures and practicals if time allows26

Domestic and institutional clean stoves

programme

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1. Implementers MOE – Coordination and policy and

legislation

ERC – Lead agency in formulation and

development of legislation

KeBS - Lead agency in formulation and

development of Standards

KEFRI – Database of suitable biomass fuels

and their sustainable supply

University of Nairobi, KEFRI and KIRDI –

Performance testing of stoves

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• Tower Power (K) Ltd to put up two biomass

power plants in Mariakani and Baringo with

estimated total capacity of 23 MW using

Prosopis juliflora (Mathenge) as feedstock

• Construct an Industrial Park to benefit communities

• Potential to create direct and indirect employment to

over 1000 beneficiaries

• Mogotio & Rea Vipingo where sisal waste will be

used as feedstock to generate approx. 1.5MWe

• E-Z Energy carrying out feasibility studies to

generate 30MW of bioelectricity in Turkana

using P. Juliflora

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2.0.2 Local and International Investors

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2.1 Role of biogasification technology in

climate change mitigation

• Clean energy technology generating

Combined Heat and Power (CHP) without

GHG emissions

• Utilises carbon neutral feedstock currently

having minimal economic applications

• Biochar generated as by-product has

potential of carbon sequestration and as

carbon sink besides improving soils

12/11/2012 29

Biogasification technology vs climate

change mitigation

• Reduced deforestation due to access to

clean energy from bioelectricity

• Increased reforestation for sustainable

supply of fuels for bioelectricity from

purposely grown energy plantations

– Precipitation in form of flashfloods minimised

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2.0 Challenges Technical and non-technical barriers have slowed

done investments in biomass gasification technology.

Unlike the emerging economies (China and India) and

Europe where technology is advanced and always

evolving, the region lack reliable and high quality

technology transfer framework which works and can be

upscaled and commercialised

Lack of adequate goodwill and basic incentives to

increase production of lignocellulosic energy crops

hence uncertainty of sustainable supply of biomass

fuels. Why are we unable to develop viable business

models to spur sustainable supply?

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• Unfavourable policy, legal and institutional structures

such that drivers of bioelectricity /bioheat (small CHPs)

such as feed-in tariff regimes, green certificates and tax

holidays are weak. Policy makers and investors require

information on bioenergy that can lead to development of

investment plans and wealth creation

• Lack strategic partnership and linkages in Research for

Development and Deployment (R4DD) in biomass solid,

liquid and gaseous energy sector due to unavailability of

relevant facilities due to weak and unde

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3.0 Opportunities in biogasification

technology

12/11/2012

Opportunity No.1. Combined Heat and Power (CHP) Gasifiers

• There is potential to supply rural households with piped

cooking wood gas, heat for drying processes and small

scale bioelectricity for lighting market, health and social

centres

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Applications – Which way for the region for CHP???

1. LS applications (>500 kW): specialized fluidised bed or fixed bed

installations. Equipment custom built, fully automized. Costs ~US$

1000 per installed kW and upwards

2. MS applications (30 -500 kW): FB equipment. Cost range 300 - 800

US$/kW (gasifier only). Used in S&M size industries (2o wd ind.,

s/mills, coconut desiccating factories, etc.), power for remote

communities

3. SS applications (7 - 30 kW): Village applications (e.g. village maize

and cereal mills, small-scale sugar crushers etc.). Cost <150

US$/kW, extremely reliable and requires no special operation and

maintenance skills

4. Micro scale applications (1 - 7 kW): Used by small and medium

farmers to provide power for irrigation systems. Mobile equipment

12/11/2012 34

12/11/2012A simple Gasifier System

A simple Gasifier AssemblyHosahalli Gasifier

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Opportunity No. 2: Sustainable production and processing of

biomass fuels

Purposely grown energy crops, e.g. Bamboo, P. juliflora

Initiate Biomass Trade Centres / Business models

Community contract schemes

Land lease agreements with National and County Governments

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Opportunity No. 3: Processing and packaging fuels for

biogasification

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3. Pelletizing Process

• Extrusion process – Sized, dried and

conditioned feedstock conveyed thro’

extruder to form pellets of uniform size,

moisture and density

• Cooling process – Temp. of pelletized

wood is ~60-80oC with ~15% MC. Pass it

thro’ cooler to reduce MC to ~3-4%

1. Masticating Process:

Sort, masticate and blend waste wood and other

feedstock into pellets of uniform size and MC

2 Drying Process:

Convey feedstock to rotary dryer to dry

feedstock from 60% MC to ~15-20% MC

4. Packaging Process

After cooling, package pellets for

storage into 800-1000kgs per bag

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a) Hand shaped briquettesb) Simple mould from a perforated bottle and variations of briquettes

II) Lever-presses (wet pulp, low-moderate pressure)

a) Paper-brick Maker b) Wooden presses

I) Manual briquetting options (wet pulp, low pressure

4.0 Lack of state-of-the-art fuel processing & packaging

Technology - Densification techniques

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III) Briquetting options: medium pressure, moist-dry feedstock

a) Screw-type extruder presses Briquette sale by bicycle in Dacca

b) Piston pressBriquette-making from saw-dust with a hydraulic press in Karamoja (Uganda)

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IV) Biomass Pelletising

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a) Flat-die presses

Maxi-pellets‘ pressed through 20-mm-holes of a flat-die at a rate of 50-80 kg/h, depending on material

Rollers pushing sawdust through the holes of a small 210 mm diameter flat-die disk

b) Ring-die presses

Ring-die press from AgriconSA in actionRing-die press

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Opportunity No. 4: Tapping into the Carbon

Markets

• Strengthening and enhancing linkages and

partnership within the region

– European Bioenergy Conferences

• Technologies from European companies and

Institutions of higher learning e.g. Finland,

Sweden, Austria, United Kingdom and Australia

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Case study 1• Gasifier total package ~ US$80-90,000. Use a spark head

Caterpillar (Natural Gas base) in the 70-90 kWe

range. When derated for Syngas it would yield roughly 30-

40kWe (depending on the feedstock).

• The good news is, that we can definitively show that for

under 150,000 Euros a community can organize a Forestry

Management program, and generate all their own power

without importing a drop of fuel, and without injury to the

environment. Sustainable energy with sustainable forestry

and agriculture......

• In purely economic terms, consider that the electrical rates

in Nairobi which are between 28-36 cents(US) per

kWeH. This system will harvest, process, and deliver

roughly 20,000 kWeH per month, at roughly 32 cents per

kWeH that's worth around US$6,400 a month, which means

that the system pays for itself in less than a year and a

half... roughly 16 months. It would seem that there is huge

justification for this package on those grounds alone.

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The Energy Resources Institute (TERI)

• Complete hardware - Biomass gasifier reactor, cleaning and cooling

equipment’s and an engine. The cleaning system consists of a heat

exchanger, cyclone separator, venture scrubber, bag house filter

and a paper filter. The Engine provided shall be a standard make

water cooled engine with alternator.

• Supply costs

– PRICE FOR GASIFIER SYSTEM 1 No USD 42,000 ~Kshs 3,570,000

– PRICE FOR THE GAS ENGINE 1 No USD 38,000 ~Kshs 3,230,000 i.e.

Cummins make MODEL – 855G.

• Supervision for design and installation inclusive of air travel,

accommodation and meals – Kshs 1,500,000

• Training of local engineers and technical staff – Kshs 1,000,000

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ECONOMICS OF A BIOMASS GASIFICATION POWER PLANT

(55 kWe in Pure Gas mode )

The capital cost includes all equipment, building and projectdevelopment. It does not include the costs of land and grid

connection, if any.

Gasifier rating (Biomass throughout) kg/h 65

Engine rating in pure diesel mode kVA 110

Engine rating in gas fuel mode kw 55

Capital cost of the Plant (after subsidy) Rs. Lakhs 13.5

Equity % 70

Dividend on equity % 10

Loan % 30

Interest Rate % 13

Repayment period years 10

Average Load kWe 40

Diesel Price Rs./Lt. 22,00

Total CO2 savings Tons/yr. 125- 250

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4.0 CONCLUSION

1. Although biomass gasification technology and its

utilization is in its nascent stages in Kenya, there are

many initiatives towards development and deployment

of the technology by Government and its lead

institutions, local & international NGOs and investors

2. Biomass gasification technology has high potential in

the region due to insecurity of supply of conventional

fossil fuels, availability of biomass fuels in abundance,

cheap labour and increasing technical knowhow

3. DownDraft Imbert gasifiers being comparatively easy to

build and operate, are the most appropriate for the

region as a source of decentralized bioelectricity and

bioheat supply to rural communities and industries.

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4.0 CONCLUSION

• Bioelectricity has huge role in climate

change mitigation

– Carbon neutral; Sequestration and carbon

sink using biochar

• Reduced deforestation and increased

reforestation of purposely grown energy

plantations

• Fossil fuels substitution especially

kerosene by increased access to

bioelectricity to households12/11/2012 46

4.1 Recommendations

1. We need realistic and practical

technology transfer on biogasification

with strong country level/community level

ownership

2. We need to develop a business- based

model on sustainable fuels supply to

ensure technology sustainability

3. We need to strengthen our strategic

partnership and linkages in the region to

benefit from economies of scale12/11/2012 47

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THANK YOU ATTENTION

THANK YOU FOR LISTENING

END OF PRESENTATION

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