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Biomass

Forest

Mill residues

Agricultural crops & waste

Wood & wood waste

Animal wastes

Livestock operation residues

Aquatic plants

Municipal & Industrial wastes

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Biomass Stores Energy And Carbon

Source: Boyle, RenewableEnergy, 2nd edition, 2004

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Uses Of Biomass Energy

More than 1 billion people burn fuel-wood orcharcoal as their principal power source forcooking, heating, etc.

N e w u se s

Converting into liquid fuel for vehicles (ethanol, bio-diesel)Collecting and using methane from landfills or

livestock manureCombusting biomass in biomass power plantsBurning with coal in power plants built for bothConverting into gases to improve electricity

generation

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Biomass is a Renewable Sourceof Energy

Biomass is plant material and animalwaste used to produce energy.

It is the oldest form of renewableenergy known to humans.

The energy that biomass materialscontain comes directly from the sun.

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Biomass is a Renewable Sourceof Energy

Plants store the sun’s energy likebatteries. When these materials arecombusted they release that energy,which can be trapped to producesteam, heat water, or makeelectricity.

As long as we do not use more

biomass than we can regeneratethrough dedicated croplands andother sources, biomass is asustainable and clean source of

renewable energy.

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Making Energy From Biomassis Good for the Environment

Biomass energy can reduce airpollution, provide important wildlifehabitat, reduce soil erosion, andimprove soil quality.

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Biomass crops need carbon dioxideto thrive, meaning that all of the CO2

released by their combustion isremoved from the atmosphere asthey grow. The process provides nonet increase in atmospheric carbondioxide levels.

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Fossil fuels, on the other hand,represent carbon which has been

trapped underground. When thesefuels are burned they release carbonthat would not otherwise have madeits way into the atmosphere, thuscontributing to climate change.

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Main features of biomass energy technology

CO2 環透過植物衡

產生沼氣

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Biogas

This is the mixture of gas producedby methan-ogenic bacteria whileacting upon biodegradable materials

in an anaerobic condition. Biogas is mainly composed of 50 to

70 percent methane, 30 to 40percent carbon-dioxide (CO

2) and

low amount of other gases as shownin next Table.

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Biogas

Biogas is about 20 percent lighterthan air and has an ignitiontemperature in the range of 650 to

750

C.It is an odorless and colourless gasthat burns with clear blue flamesimilar to that of LPG gas.

Its calorific value is 20 Mega Joules(MJ) per m3 and burns with 60%efficiency in a conventional biogas

stove.

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Biogas

Biogas like Liquefied Petroleum Gas(LPG) cannot be liquefied under normaltemperature and pressure.

Critical temperature required forliquefaction of methane is -82.1oC at

4.71MPa pressure, therefore use ofbiogas is limited nearby the biogasplant.

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Biogas

Parameters Optimum

value

Temperature (oC) 30-35

pH 6.8-7.5

Carbon/Nitrogen

ration (C/N)

20-30

Solid content (%) 8-10

Retention time (days) 20-50

Optimum conditions for biogas production

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Commonly used feed material forbiogas generation

Animal Wastes

Human Wastes

Agricultural Wastes Waste on Aquatic Origin

Industrial Waste: Sugar factory, Tannery,

Paper etc.

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Biogas Production Potential From

Different Wastes

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Power Generation

Biogas can partly replace diesel to run IC(internal combustion) engines for waterpumping.

Small industries like flour mill, saw mill,oil mill etc.

Biogas can similarly be used to produceelectricity. Dual fuel engines (80% biogas& 20% diesel) are now –a-days gainingimportance for using.

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Biogas requirements for powergeneration

Purpose Specification Gas required m3/hour

Lighting 200-casndel

power

40-watt bulb

2-mantle

0.1

0.13

0.14

Gasoline

engine

Per HP 0.43

Diesel engine Per HP 0.45

Incubator Per m3 0.60

Space heater 30 cm diameter 0.16

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Direct Burning Biogas

5 kg Dry Dung Product 1 cubic meter biogas

10460 kcal Gross Energy 4713 kcal

10% Device Efficiency 55%

1046 kcal Useful Energy 2592 kcal

None Manure 10 kg Air dried manure

f i l

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Components of Various Fuels

Name of fuel Calorific Value

(kcal)

Mode of Burning ThermalEfficiency,

%

EffectiveHeat

(kcal)

Gobar gas (m3) 4713 In Standard Burners 60 2828

Kerosene (Lt.) 9122 In Pressure Stove 50 4561

Fire wood (kg) 4708 In Open Chulha 17.3 814Cow Dung Cakes (kg) 2092 In Open Chulha 11 230

Charcoal (kg) 6930 In Open Chulha 28 1940

Soft coke (kg) 6292 In Open Chulha 28 1762

Butane (kg) 10882 In Standard Burners 60 6529

Furnace oil (Lt.) 9041 In Water Tube Boiler 75 6781

Coal Gas (m3) 4004 In Standard Burners 60 2402

Electricity (kwh) 860 Hot Plate 70 602

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Advantages

By relatively simple means, biogas can beutilized as a source of energy in integratedfarming. In addition, the use of biogas implies anumber of advantages of ecological as welleconomical character.

The environment is being destroyed by thedemand for firewood and charcoal. To avoidcatastrophe, it has to be protected, and oneway of doing this is to use biogas.

One major problem for people who areeconomically or geographically disadvantagedis to get electricity or fossil fuels for cookingand lighting. At the moment, biogas seems tobe the most logical source of cheap energy.

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Advantages

In the developing countries, women spendmany hours collecting firewood. This is a bigburden on them, and their time could be used

more productively. Cooking with firewood produces a lot of smoke,

which is bad for the health of the women, whotend the kitchen fire. The smoke pollutes the air,

and can cause problems with lungs, eyes etc.The flame from burning biogas does not needtending.

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C/N Ratio

The relationship between the amount of carbon andnitrogen present in organic materials is expressed interms of the Carbon/Nitrogen (C/N) ratio.

A C/N ratio ranging from 20 to 30 is consideredoptimum for anaerobic digestion.

If the C/N ratio is very high, the nitrogen will beconsumed rapidly by methanogens for meeting theirprotein requirements and will no longer react on theleft over carbon content of the material. As a result, gasproduction will be low.

On the other hand, if the C/N ratio is very low, nitrogenwill be liberated and accumulated in the form ofammonia (NH4), NH4 will increase the pH value of thecontent in the digester.

A pH higher than 8.5 will start showing toxic effect onmethanogen population.

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Digestion

Digestion refers to various reactions andinteractions that take place among themethanogens. nonmethanogens and

substrates fed into the digester as inputs.This is a complex physio-chemical andbiological process involving different

factors and stages of change. Thisprocess of digestion (methanization) issummarized below in its simple form.

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More Details on the Digestion

Process

Volatile

Solids (VS)Volatile

organic acids

Acid forming

bacteria

Methane, carbon dioxide,

water, trace gases

Methane forming

bacteria

Odor

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What is Anaerobic Digestion?

by Anaerobic Microbes

Conversion of Organic Matter

to Biogas

Methane ~ 60%Carbon Dioxide ~ 40%

Hydrogen sulfide ~ trace

and Manure Effluent

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Anaerobic Digestion

Use a heated container to acceleratethe degradation of the manure.

Microorganisms produce a fuel gasand degrade the manure.

Less odors are produced whencompared to non controlledanaerobic digestion

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Advantages of Digestion

Total waste management system

– Pollution control

– Odor control

– Nutrient conservation

– Greenhouse gas reduction

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Disadvantages of Digestion

Is somewhat costly

Higher management levels required

Startup is sometimes difficult Storage required

– Cannot store methane as a liquid!!

Some risk of explosion

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Methanization

The principle acids produced in Stage 2 areprocessed by methanogenic bacteria to producemethane.

The reactions that takes place in the process ofmethane production is called Methanization andis expressed by the following equations.

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Biomethanization Implementationand its Effects

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Basics of Bio-gas Digesters

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Classification of BiogasDigester

Floating gasholder type plantsFixed dome

C i f t t f bi di t

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Comparison of two types of biogas digesters

Floating gas holder type Fixed dome type

Gas is release at constant

pressure

Gas is released at variable

pressure

Identifying the defects in gas

holder easy

Identifying defects is difficul t

Cost of maintenance is high Cost of maintenance is low

Capital cost is high Capital cost is low

Floating drum does not allow to

use the space for other purpose

Space above the drum can be

used

Temperature is low during winter Temperature is high during winter

Life span is short Life span is comparatively long

Requires relatively less

excavation

Requires more excavation work

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Popular design of Biogaspant in India

KVIC (Khadi & Village IndustriesCommission) Design (Floating DrumType)

Janata Design (Fixed dome type)

Deenbandhu Design

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Calculation of cost of constructionand installation of KVIC model

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Floating Gasholder Type Plants

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Floating Gas Holder System(KVIC Model)

In this design, the digesterchamber is made of brickmasonry in cement mortar.

A mild steel drum is placedon top of the digester tocollect the biogas produced

from the digester. Thus,there are two separatestructures for gas productionand collection.

With the introduction of fixeddome Chinese model plant,

the floating drum plantsbecame obsolete because ofcomparatively highinvestment and maintenancecost along with other designweaknesses.

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Fixed Dome Digester

i d i

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Fixed Dome Digester(Chinese Model)

i d i

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Fixed Dome Digester(Chinese Model)

Fixed dome Chinese model biogas plant (also calleddrumless digester) was built in China as early as 1936.

It consists of an underground brick masonrycompartment (fermentation chamber) with a dome onthe top for gas storage.

In this design, the fermentation chamber and gas holderare combined as one unit.

This design eliminates the use of costlier mild steel gasholder which is susceptible to corrosion.

The life of fixed dome type plant is longer (from 20 to 50

years) compared to KVIC plant. Based on the principles of fixed dome model from China,

Gobar Gas and Agricultural Equipment DevelopmentCompany (GGC) of Nepal has developed a design and hasbeen popularizing it since the last 17 years.

The concrete dome is the main characteristic of GGCdesign.

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Janata Model

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Deenbandhu Model

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Deenbandhu Model

In an effort to further bring down theinvestment cost, Deenbandhu model was putforth in 1984 by the Action for FoodProduction (AFPRO), New Delhi.

In India, this model proved 30 percentcheaper than Janata Model (also developed inIndia) which is the first fixed dome plantbased on Chinese technology.

It also proved to be about 45 percent cheaperthan a KVIC plant of comparable size.

Deenbandhu plants are made entirely of brickmasonry work with a spherical shaped gas

holder at the top and a concave bottom.

D b dh T Bi G

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Deenbandhu Type Bio GasPlants

http://www.sintex-plastics.com/deenabandu_g.htm

B Di t





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Bag Digester(Taiwanese Model)

B Di t

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Bag Digester(Taiwanese Model)

This design was developed in 1960s in Taiwan. It consists of a long cylinder made of PVC or red

mud plastic. The bag digester was developed to solve the

problems experienced wit h brick and metaldigesters. A PVC bag digester was also tested in Nepal by GGC

at Butwal from April to June 1986. The studyconcluded that the plastic bag bio-digester could be

successful only if PVC bag is easily available,pressure inside the digester is increased andwelding facilities are easily available.

Such conditions are difficult to meet in most of therural areas in developing countries.

P f b i d bil

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Pre fabricated mobile typeBiogas plants

State of the art proven biogasplant, easy to install. moreefficient than the conventionalone. better energy recovery.

BIOGAS - Fuel of the future.

Free energy from the waste.Only one time investment.

Investment can be recoveredwithin ONE YEAR. Availablefrom 6m3/day to 1000m3/day.

Power can be generated fromthis plant of capacity more than50m3 for the use like gardenlighting, street lighting, homelighting etc.

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Biogas Holders

http://www.arjuntarpaulins.net/biogas-holders.html

Dowac Systems & Projects India Pvt Ltd





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The solid waste fromindustrial kitchens,butchary house,segrigated bio-degradable waste ofhousing colonies can betreated to get valuablebi-products such as biomethane gas for heatingand rich fertilizer.

The large quantity ofbiogas can be convertedin to electricity forgarden lighting.


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Plug-Flow Digester - A small “plug” of slurry is pumped into

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g g g y

one end each day, causing a comparable amount to flow out

of the other end into the storage basin in the background.

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http://www.arkatechnologies.in/biogas-plant-supplier-pune.shtml

Best way to DisposeKitchen Waste

Suitable for Flat System Ready to Use model

Portable system

Molded in one tough piece

Leak proof and strong Light weight and easy to

carry anywhere

Cooking Gas is Output

Liquid Manure isByproduct

1 D ti t t h d









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1: Domestic waste water heads

to sewage processing plant

2: Settlement tanks separate

sewage into clean water andsludge

3: Anaerobic digesters break

down the waste and produce a

thick, odourless waste and

methane. Waste solids used as

fuel or fertilizer.

4: Biogas plant cleans methane to remove impurities, adds

odorant to "smell like gas"

5: Clean biomethane pumped back into national network

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Use of Biogas

Cooking

Lighting,

Refrigeration

Running internal combustion engine.

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Cooking Fuel

The most common use of biogas isfor cooking.

A 2 cubic meter biogas plant can

replace, in a month, fuel equivalentof 26kg of LPG (Liquefied Natural gas)or 37 Lt. of Kerosene or 88 kg of

Charcoal or 210 kg of fuel-wood or740 kg of Animal dung.

Bio Gas Used In the

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Bio Gas Used In theIndustrial Kitchen

Biogas Purification: Removing

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Biogas Purification: RemovingHydrogen Sulfide

– Removal Using Metal Oxides andHydroxides

– Activated Carbon

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Recovered Sulfur

Additonal Benefits Of H s

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Additonal Benefits Of H2sRemoval

Impact On Surrounding air.

H2S is Highly Corrosive – Can

damage other equipments andexpensive instruments in the vicinity.

Health Hazard and odour nuisance.

Typical Process Flow Diagram

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Typical Process Flow DiagramBioskrubber

Buffer TankSulphur

Reactor

Elemental

Sulphur

Sulpher

Drying Bed Settling Tank

Caustic

Tank

Nutrient

Tank

Gas Holder

Clean Gas

Raw Gas

Absorber

Air Blower

GasEn ine

Power

Generation

Power

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Biogas Flame

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Biogas Lamp for Lighting

Natural Gas = Biogas

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Natural Gas BiogasBut with Some Important Exceptions

Fossil Fuel

Less GHGEmissions

Methane

Renewable

FuelNet Zero

GHG

emissions

Natural Gas

Both good forair quality

Biogas

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Swedish Biogas Industry

Sweden is world leader in biogas production forvehicle fuel

– 17 biogas plants

– 24 biogas-only refueling stations– 20 biogas/NG (blended) refueling stations

– >4,500 NG and bi-fuel (NG and gasoline)

vehicles– Dedicated local biogas pipeline networks

– Biogas injected into Swedish NG pipeline

network

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Sweden Biogas Industry

25 biomethane production(refineries) facilities

65 biomethane filling stations

Industry growing at annual rate of15-20%

>8,000 methane gas vehicles inSweden

50% of methane from bio sources

Biomass Potential for

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Biomass Potential forBiogas in Sweden

Theoretical potential for digestion of organic materials to

meet 20% of the energy needs of the transportation sector

Today’s Digester Process

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Today s Digester Process

Flow

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Digester Gas Upgrading

Raw digester gas approx. 65% methane(CH4) and 35% CO2

– Can be used to create electricity but not

as a transportation fuel

Digester gas must be upgraded to biogasquality to be used as vehicle fuel for

CNG/LNG vehicles• > 92% methane

• Remove H2S, H20 and other impurities

Tomorrow’s Digester & Gas

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Tomorrow s Digester & Gas

Upgrading Process Flow

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