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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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Making Energy From Biomassis Good for the Environment
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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Making Energy From Biomassis Good for the Environment
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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Dowac Systems & Projects India Pvt Ltd
Dowac Systems & Projects India Pvt Ltd
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Dowac Systems & Projects India Pvt Ltd
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.
Dowac Systems & Projects India Pvt Ltd
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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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