projct report revised v2.0

ACHU B. 88030141ALEX T. KARIYIL 88030145HARIKRISHNAN K. S. 88030161NIDHEESH M. N. 88030175NITHIN GOPAL 88030176PRAVEESH A. P. 88030179TONY THOMAS 88030201VIMAL THOMAS 88030204

BIO-ELECTRICITY

CARMEL POLYTECHNIC

ELECTRICAL & ELECTRONICS ENGINEERING

PROJECT REPORT

GUIDE:

Mr. SREEKANTAN NAIR

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ACKNOWLEDGEMENTThis project was a mammoth task to accomplish and would not have been possible

without the support of friends and teachers and continuous encouragement from well-wishers in general. I gratefully acknowledge Rev. Fr. Cyriac Kurian, Principal, Carmel Polytechnic and Smt. LIzz Joseph, Head of the Department, Electrical and electronics engineering for providing the finest facilities for the successful completion of this endeavour.

I am deeply indebted to Mr. S. Sreekantan Nair, who guided me along the course of this project sharing his valuable time, skill and wisdom. He was the prime source of inspiration behind this idea and the motivation factor at moments of despair.

I would like to thank profusely Mr. Biju, for the necessary technical assistance he gave. The enthusiasm he showed and the willingness to bear with me during the impatient hours on the outcome of this project was remarkable. I am grateful to Fr. Josekutty Chacko, hostel warden, for the kindness he showed in allowing free access to the hostel biogas units.

Finally the constant support and encouragement of Carmel Polytechnic College, especially, the staff members of the Department of EEE, workshop instructors, and friends alike, should not go unmentioned. This project is the result of the hard work and prayers of a lot of people and I see the opportunity to be involved in this activity as a blessing of Almighty himself.

ACHU B. 88030141

ALEX T. KARIYIL 88030145

HARIKRISHNAN K. S. 88030161

NIDHEESH M. N. 88030175

NITHIN GOPAL 88030176

PRAVEESH A. P. 88030179

TONY THOMAS 88030201

VIMAL THOMAS 88030204

| ELECTRICAL & ELECTRONICS

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CONTENTS CERTIFICATE - 1 ACKNOWLEDGEMENT - 3 INTRODUCTION - 5 ENERGY FROM BIOGAS

What is biogas? - 6 The technology - 7

PREPARATION OF BIOGAS - 9

PROPERTIES OF BIOGAS

Composition of Biogas - 13

Purification of Biogas - 14

Properties of Biogas - 17

Advantages of Biogas - 19

Potential benefits of Biogas - 20

GENERATION OF ELECTRICIY FROM BIOGAS - 21 Biogas in IC engines - 23 Practical Difficulties - 25 Performance - 26


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Exhaust Emissions - 26

Methane vs. Petrol - 28 The main parts of a waste-to-electricity plant - 28

IMPLEMENTATION - 29 Biogas plant - 30 Silica gel chamber - 31 Surge absorber - 32 LPG - 32 IC engine - 33 Performance & operational parameters - 39 Alternator - 40

PARAMETERS AFFECTING SYSTEM PERFORMANCE Technical parameters - 42 Economic parameters - 43

MARKETING POSSIBLITIES BIOTECH - 44 Others - 45

CONCLUSION - 46

PROJECT ESTIMATE - 48

REFERENCE - 49


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INTRODUCTIONEnergy resources of a nation form the backbone of its

development. Industrial growth, agricultural sector and the standard of life in general depend upon energy. But, today, the world is passing through a phase of energy shortage. The increase in population and the over-exploitation of the conventional resources, mainly oil reserves, are pointed out as the chief reasons for this situation.

In a nation like India, who is striving to become a superpower in the coming years, the importance of energy demands cannot be underestimated. The specter of economy ruin due to depleted oil reserves has changed the interest of scientist and research work towards alternative sources of energy.

The serious hazards created by environmental pollution, also, should not be neglected. Measures to monitor, control and reduce pollution are of prime importance.

This project is an attempt to offer a creative solution for the problems mentioned above. I believe that the challenges posed by energy shortage and pollution issues can be tackled, at least on a small scale, from the outcome of this research.

“Bio-Electricity” uses a biogas plant and an engine-generator set. The biogas produced in the plant is used to drive an IC engine which is coupled to an alternator, thus, giving electrical energy.


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ENERGY FROM BIOGAS

What is Biogas?

Biogas typically refers to a gas produced by the biological breakdown of organic matter in the absence of oxygen. Biogas originates from biogenic material and is a type of biofuel. Biogas is produced by anaerobic digestion or fermentation of biodegradable materials such as biomass, manure, sewage, municipal waste, green waste, plant material and energy crops. This type of biogas comprises primarily methane and carbon dioxide. Other type of gas generated by use of biomass is wood gas, which is created by gasification of wood or other biomass. This type of gas consists primarily of nitrogen, hydrogen, and carbon monoxide, with trace amounts of methane.

The gases methane, hydrogen and carbon monoxide can be combusted or oxidized with oxygen. Air contains 21% oxygen. This energy release allows biogas to be used as a fuel. Biogas can be used as a low-cost fuel in any country for any heating purpose, such as cooking. It can also be used in modern waste management facilities where it can be used to run any type of heat engine, to generate either mechanical or electrical power. Biogas can be compressed, much like natural gas, and used to power motor vehicles and in the UK for example is estimated to have the potential to replace around 17% of vehicle fuel. Biogas is


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a renewable fuel, so it qualifies for renewable energy subsidies in some parts of the world.

The TechnologyBiogas dates as far back as the 16th century, when it was

used for heating bath-water in Persia. It has been used in India for almost a hundred years (Sampat, 1995). The Indian government introduced large-scale biogas production in 1981 through the National Project on Biogas Development. Biogas is produced by extracting chemical energy from organic materials in a sealed container called a digester. 2 million biogas plants were in operation in 1995, and about 10 million rural Indians were benefiting from the electric power and cooking fuel the gas provided, and also from the rich agricultural fertilizer the plant produces as a byproduct.

Central to the generation of biogas is the concept of anaerobic digestion, also called biological gasification. It is a naturally occurring, microbial process that converts organic matter to methane and carbon dioxide. The chemical reaction takes place in the presence of methanogenic bacteria with water an essential medium. The anaerobic digestion process, as the name states, is one that functions without molecular oxygen. Ideally, in a biogas plant there should be no oxygen within the digester. However, efforts to completely remove it will be prohibitively expensive. Oxygen therefore exists in the digester,


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dissolved mainly in water. Fortuitously, some microbes within the digester are facultative anaerobes, i.e. they utilize oxygen and lower the dissolved oxygen concentration to levels suitable for other anaerobic microbes to perform their chemical reactions. Oxygen removal from the digester is important for two main reasons. The presence of oxygen leads to the creation of water, not methane. Also, oxygen is a contaminant in biogas and also a potential safety hazard. Due to presence of oxygen, calorific value of biogas becomes low.

First, cow dung, the primary raw input for almost all operating biogas plants is widespread and easily available. India has more cattle than any other country (450 million head, 19% of the world population).

Second, the cow is held in religious veneration and its products are considered purifying agents. Hence, there is a universal acceptance of even its dung, which otherwise would instinctively be thought of as repulsive. Dung (or gobar in Hindi) is widely used in India for house construction (as an infill material and external plaster), in religious rituals, as composted fertilizer and as a cooking fuel (dung cakes). Dung accounts for over 21 percent of total rural energy use in India, and as much as 40 percent in certain states of the country.

Third, only 27% of rural India has access to electricity supplied by the national grid (ostensibly, 84% of all villages are connected). Localized biogas plants obviate the dependency on


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the grid by producing energy from a locally controlled and easily accessible raw material.

PREPARATION OF BIOGAS

A biogas plant is the name often given to an anaerobic digester that treats farm wastes or energy crops.

Biogas can be produced utilizing anaerobic digesters. These plants can be fed with energy crops such as maize silage or biodegradable wastes including sewage sludge and food waste. During the process, an air-tight tank transforms biomass waste into methane producing renewable energy that can be used for heating, electricity, and many other operations that use any variation of an internal combustion engine.


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Landfill gas is produced by wet organic waste decomposing under anaerobic conditions in a landfill. The waste is covered and mechanically compressed by the weight of the material that is deposited from above. This material prevents oxygen exposure thus allowing anaerobic microbes to thrive. This gas builds up and is slowly released into the atmosphere if the landfill site has not been engineered to capture the gas.


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Micro Organisms And Mechanism Of Biogas Production

a. Micro Organisms-

An organic waste consist of many organisms but the organisms useful for biogas production are i. Aerobic.ii. Anaerobic.

b. Constituents of Organic Waste?The organic waste contains many constituents such as cellulose, Hemicelluloses, lignin, proteins, and starch, water-soluble, fats, Soluble etc.

c. Mechanism of biogas production: -Stage 1 It involves the decomposition of cellulose, hemicellulos Lignin, starch, protein, fats etc. Into simpler organic compounds like acids, alcohols and gases like CO2, H2, and NH3, H2S etc. by aerobic and anaerobic Micro-organisms. Stage 2: - The anaerobic organism or methane bacteria utilize simple carbon compounds available from first stage and produce methane.This is biogas production.


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Bio-gas plants

There are two types of plants-

i. Fixed dome type

ii. Floating gas holder type


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PROPERTIES OF BIOGAS

Composition of BiogasThe biogas from a biogas plant is a mixture of several gases.

The composition of biogas varies depending upon the origin of the anaerobic digestion process. Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55–75% CH4 or higher using in situ purification techniques. As-produced, biogas also contains water vapor, with the fractional water vapor volume a function of


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biogas temperature; correction of measured volume for water vapor content and thermal expansion is easily done via algorithm.

Methane (CH4) - 50-68%Carbon monoxide (CO2) - 25-35%Hydrogen (H2) - 1- 5%Nitrogen (N2) - 2- 7%Oxygen (O2) - 0- .1%Hydrogen Sulphide (H2S) - Rare

Out of these CO2 does not help in combustion process but reduce the calorific value of biogas. H2S is in minor quantity but it has corrosive action on combustion chamber and also reduces calorific value of biogas. Also traces of moisture are to be removed for better thermal efficiency. So harmful gradients are removed and use only methane as a fuel.


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Purification of Biogas

Raw biogas produced from digestion is roughly 60% methane and 29% CO2 with trace elements of H2S, and is not high quality enough if the owner was planning on selling this gas or using it as fuel gas for machinery. The corrosive nature of H2S alone is enough to destroy the internals of an expensive plant. The solution is the use of a biogas upgrading or purification process whereby contaminants in the raw biogas stream are absorbed or scrubbed, leaving 98% methane per unit volume of gas. There are four main methods of biogas upgrading, these include water washing, pressure swing absorption, selexol absorption and chemical treatment. The most prevalent method is water washing where high pressure gas flows into a column where the carbon dioxide and other trace elements are scrubbed by cascading water running counter-flow to the gas. This arrangement can deliver 98% methane with manufacturers guaranteeing maximum 2% methane loss in the system. It takes roughly between 3-6% of the total energy output in gas to run a biogas upgrading system.

Removal of H2S

The gas coming out of system is heated to 1500 C and over ZnO bed, maintained at 1800 C leaving process gas


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free of H2S. ZnO + H2S = ZnS + H2O.ZnSO4 + 2NaOH = Zn (OH) 2 + Na2SO4

Removal of CO2 CO2 is high corrosive when wet and it has no combustion value so its removal is must to improve the biogas quality. The processes to remove CO2 are as follows a) Caustic solution, NaOH - 40% NaOH + CO2 = NaHCO3

b) Renfield process K2CO3 - 30 % K2CO3 + CO2 = 2KCO3

Removal of NH3

The chemical reaction is:NH3 + HCL =NH4Cl


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Removal of H2OFor the removal of moisture, the gas, from above reaction, is passed through the crystals of white silica gel.


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Properties of BiogasIn its pure state, it is color less, odorless, tasteless. For safety

reason, an odorant is added so that any leak can be easily detected because of typical smell.

The composition of bio gas is never constant. Methane is by far the largest component, its presence accounting for about 95% of the total volume. Methane is a simple hydrocarbon, a substance consisting of carbon & hydrogen. There are many of these compounds each has its own carbon & hydrogen atoms joined together to for a particular hydrocarbon gas as fuel gas. Methane is very light fuel gas. If we increase the number of hydrogen & carbon atoms, we have got progressively heavier gases, releasing more heat, therefore more energy, when ignited. Specific gravity of methane is .55 which is less than petrol & LPG. This means that biogas will rise if escaping, thus dissipating from the site of a leak. This important characteristic makes biogas safer than other fuels. It does not contain any toxic component; therefore there is no health hazard in handling of fuel.

The air to biogas (stoichiometric) ratio by volume for complete combustion is 9.5:1 to 10:1.Biogas has a very slow flame velocity, only .290 m/s. at its highest. The range of flammability is 4 to 14% which can give good combustion efficiency.

Biogas has very high octane number approximately 130. By comparison, gasoline is 90 to 94 & alcohol 105 at best. This means


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that a higher compression ratio engine can be used with biogas than petrol. Hence, cylinder head of the engine is faced so that clearance volume will be reduced & compression ratio can sufficiently increase. Thus volumetric efficiency & power output are increased. Because of its high octane value the detonation occur however high the compression may be. The Boiling point of biogas is above 300 degree Celsius while the calorific value is 35.390 MJ/m3.

One of the promising renewable energy sources is biogas, which is compound gas consisting mainly of methane (CH4) and carbon dioxide (CO2). It is normally formed with the decomposition of organic substances. Because of its low energy density, the gas is generally stored in high-pressure gas bomb. To store it in a condition of high density, it is also attempted to store methane in the form of clathrate. The clathration of methane requires normally high pressure and low temperature. If the clathration of biogas and methane could be achieved under the normal pressure and temperature, this would make the gases a very useful energy source.


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Advantages of Biogas It is light fuel gas. It mixes easily with the air. It is highly resistant to knocking. Due to uniform distribution, thermal efficiency is higher. Biogas has a high octane number. It reduces pollution. Higher compression ratio can be used with biogas. Plants capital cost is low. Domestic fuels for burners used in kitchen. Not toxic to skin.

Potential benefits of BiogasBiogas consists primarily of methane and is given off in

places where decaying organic material is found. One of the primary benefits of capturing biogas generated at landfill sites, sewage waste treatment plants, and animal feedlots would be a substantial reduction in greenhouse gas emissions. Capturing and burning biogas would provide significant reductions in toxic emissions and ozone forming pollutants, and lower particulate emissions in the case of heavy-duty vehicles. In addition, water quality could be improved as a result of reduced waste runoff near sites where biogas is captured.


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The potential reductions of greenhouse gas emissions are staggering. Much of this benefit is derived from capturing and burning methane emissions that currently are released into the atmosphere. An NGV using fuel derived from biogas that otherwise would have been vented provides as much benefit as removing six petroleum-fueled vehicles from the nation's highways. Stated differently, use of biogas in NGVs would produce 600 percent less greenhouse gas emissions when compared with using petroleum as a motor fuel.

Using biogas that currently is flared instead of vented would provide about a 100% net reduction in greenhouse gas emissions when compared with burning petroleum motor fuel in a similar vehicle. Utilization of available supplies of biogas could potentially reduce the motor vehicle-related greenhouse gas emission by more than 340 million tons - a 23% reduction in overall emissions of motor vehicle greenhouse gas emissions.


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GENERATION OF ELECTRICIY FROM

BIOGASThe main advantage of the waste-to-electricity project is

that no external power is required for the operation of the plant. The power generated in the treatment plant can be utilized to meet the in-house requirement completely. Excess quantity can be utilized for any type of application, including street lighting, providing lights to the markets, and the likes.

Generally, 1.5 KW (kilowatt) of electricity can be produced from one cubic meter of biogas. Depending upon the percentage of methane content in biogas, the power generation may vary slightly. The size of the generator can be fixed depending upon the availability and the quantity of gas and the duration for the requirement of power. The gas can be utilized as the operation fuel in generators. Before feeding biogas as the fuel in generator, the gas has to be passed through a gas scrubber to remove unwanted particles, gases, moisture, and so on.


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A biogas plant with associated generator unit installed by BIOTECH

Two types of generators are used for generating electricity from biogas. One is the dual fuel model and the other is the 100% biogas model. Dual fuel models are basically diesel generator sets. In this system, the biogas is connected to the generator through air mix. Once the biogas is passed through the generator, the consumption requirement of the diesel is automatically reduced. Usually, dual fuel generators work in 80%–20% mode. In the 100% biogas engines, no other fuel is required either for starting or for operating them. Any type of petrol engine can be modified for operating the same, using biogas as the operation fuel. The imported models of 100% biogas engines are very costly and the maintenance of such systems is also very expensive. BIOTECH, a Kerala based non-governmental organization, has developed 100% biogas engines, which have been installed in various projects. And the performance of all of them has been very good.


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Biogas in Internal Combustion Engines

S. I. Engines: - The only adoption for a spark ignition engine is a gas (not gasoline!) carburetor to work at the supply pressure (just like an LPG conversion, but an evaporator would not be needed as the storage pressure is low). It is also a good idea to scrub the H2S (as it causes corrosion) and to derate the engine (unless you want to replace it each year if operating continuously).

Modification of S.I. Engine -: S.I. engines can run completely on biogas, however, the engines are required to be started on petrol at the beginning, conversion of S.I. engine for the entry of biogas, throttling of intake air & advancing the ignition timing. Biogas can be admitted to S.I. engine through the intake manifold & air flow control valve can be provided on the air cleaner pipe connecting air cleaner & carburetor for throttling the intake air.


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C.I. Engine:-

Diesel engines also need a gas carburetor and scrubbing, but require at least 10% diesel via the injectors for ignition (and cooling). The initial starting of diesel engine is done on pure diesel.

Modification of C.I. Engine: C.I. engine can operate on dual fuel & the necessary engine modification include provision for the entry of biogas with intake air, provision of carburetor & system to reduce diesel supply, advanced injection timing. The entry of biogas and mixing of gas with intake air can be achieved by providing the mixing chamber below the air cleaner which facilitate through mixing of biogas with air before entering into the cylinder. The capacity of mixing chamber may be kept equal to the engine displacement volume. The pilot injection of cycle is required to be advanced for smooth and efficient running of engine on dual fuel. The admittance of biogas into the engine at the initial stage increases engine speed and therefore a suitable system reduces the diesel supply by actuating the control rack needs to be incorporated.


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There is a wide range of thoughts on what treatments should these biogases be subjected to before being used as fuel. Most operators simply remove the water present in the biogas, leaving it to the engine manufacturers to design engines which will cope with the impurities inevitably included in the biogas (significant maintenance costs); other Operators are seriously evaluating maintenance costs against initial investments in biogas clean up technologies.

Practical DifficultiesTo use the biogas as a fuel in SI engine there are some

practical difficulties. It is not possible to compress the methane, separated from biogas by available method, because the gas could be liquefied through chilling below -161 0C.

This process is adapted by installing the units required when there use of methane separated from biogas as a fuel. Since gas cannot be compressed it requires large space for storage.


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Performance In purification method, by reducing CO2 and moisture along

H2S impurities in biogas, the engine performance is improved.

Effect of spark timing:-Biogas is slow burning fuel. Hence in order to get optimum engine performance, spark timing does not advance, and then combustion continues in major part of the expansion stroke. This reduces effective work done. By advancing, spark timing power is improved on low speed at partial throttle condition as well as high speed at full throttle condition.

Exhaust EmissionsThe exhaust emission contains three specific substances

which contribute the air pollution, hydrocarbon, carbon monoxide &oxides of nitrogen. Hydrocarbons are the unburned fuel vapor coming out with the exhaust due to incomplete combustion. Hydrocarbons also occur in crankcase by fuel evaporation. The emission of hydrocarbon is closely related to many design & operating factors like induction system, combustion chamber design, air fuel ratio, speed, load. Lean mixture lower hydrocarbon emission.


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Carbon monoxide occurs only in engine exhaust. It is the product of incomplete combustion due to insufficient amount of air in air- fuel mixture. Some amount of CO is always present in the exhaust even at lean mixture. When the throttle is closed to reduce air supply at the time of starting the vehicle, maximum amount of CO is produced. Oxides of nitrogen are the combination of nitric oxide & nitrogen oxide & availability of oxygen are the two main reasons for the formation of oxides of nitrogen. The spark advance means lower peak combustion temperature. It causes high NO concentration in the exhaust. With biogas, CO emission levels are low than that of gasoline.


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Methane vs. PetrolPower Reduction 11%CO Reduction 99%HC Reduction 99%NO Reduction 59%

The main parts of a waste-to-electricity plant

Digester, gas collector, anaerobic predigester, slurry loop system, 100% biogas generator, standby generator, biogas scrubber, dehumidifier, control panel, power distribution system, and Exes Gas reservoir.

Biogas generator unit


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IMPLEMENTATION The experiment was conducted on a Birla Yamaha

generator. A 2 stroke SI engine acts as the prime mover of the alternator in the generator set. The engine is modified to run on gaseous fuels.

Before biogas is injected into the engine it is passed through a chamber filled with silica gel to de-moisturize the gas (biogas has high moisture content. Therefore, the engine cannot run on biogas taken directly from the plant outlet).

The engine is started from LPG. Then it is switched to biogas after cutting-off the LPG supply.

A surge-absorber can be used to absorb variations in gas pressure. It is a simple arrangement consisting of a cylinder filled with biogas connected between the plant and the engine.

Pressure gauges can be used at the inlet of the engine to constantly monitor gas pressure.


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For starting

VALVE VALVE

Moist gas

Biogas plantThe method of preparation of preparation of biogas and the

types of plants used for this purpose have been discussed earlier. This experiment was conducted on both fixed dome and floating gas holder type plants successfully. The engine provided best performance when tested on gobar gas.


BIOGAS PLANT LPG

SILICA GEL CHAMBER

SURGE ABSO-RBER

ENGINE-ALTERNATOR SET

ELECTRICAL ENERGY

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Silica gel chamberBiogas coming from the biogas plant has high moisture

content. If fed directly to the engine it will not ignite and also can be harmful for the engine. In order to de-moisturize the gas it is passed through a chamber filled with silica gel. Calcium oxide can also be used, but with additional arrangement for dissipating the heat released when it absorbs water.

White silica gel is recommended over blue crystals. But the latter was used in this experiment due to economic reasons. About 100 gm silica gel is used for each run. It is to be ensured that enough space is left for accommodating the expansion of the gel after absorption. The silica gel should be replaced when it turns dark implying that it has absorbed water up to saturation point.

| ELECTRICAL &

ELECTRONICS

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Surge absorberThe gas injected in to the engine should be of constant

pressure. But the gas pressure at the outlet of the plant may vary due to different factors. A surge absorber is used to neutralize the variations of gas pressure. It is basically a cylinder filled with biogas connected between the plant and the engine. When pressure tends to decrease with the decrease in gas availability, the surge absorber supplies additional gas, thus bringing back the pressure to normal. Similarly, when pressure increases it takes in more gas neutralizing the variation. This arrangement has been excluded from the experiment as it is not inevitable for short runs of the engine.

The capacity of the cylinder is an important specification to be considered while designing a surge absorber. Pressure gauges can also be attached to constantly monitor the pressure.

LPGLPG is used to start the engine as it cannot be started on

biogas. The LPG supply is cut-off after the engine runs at rated speed. Valves or regulators are used to prevent the mixing-up of fuels. It can also be used as a back-up supply.


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IC EngineAs said earlier the experiment was conducted on a single

cylinder 2-stroke spark ignition engine (3000 rpm). A brief description on the working of a 2-stroke engine is given below.

Working of a 2 Stroke Spark Ignition (SI) engine:

In two strokes SI engine a cycle is completed in two stroke of a piston or one complete revolution (360º) of a crankshaft. In this engine the suction stroke and exhaust strokes are eliminated and


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ports are used instead of valves. Petrol is used in this type of engine.

When the piston moves from bottom dead centre to top dead centre, the fresh air and fuel mixture enters the crank chamber through the valve. The mixture enters due to the pressure difference between the crank chamber and outer atmosphere. At the same time the fuel-air mixture above the piton is compressed.

Ignition with the help of spark plug takes place at the end of stroke. Due to the explosion of the gases, the piston moves downward. When the piston moves downwards the valve closes and the fuel-air mixture inside the crank chamber is compressed. When the piston is at the bottom dead centre, the burnt gases escape from the exhaust port.

At the same time the transfer port is uncovered and the compressed charge from the crank chamber enters into the combustion chamber through transfer port. This fresh charge is deflected upwards by a hump provided on the top of the piston. This fresh charge removes the exhaust gases from the combustion chamber.

Again the piston moves from bottom dead centre to top dead centre and the fuel-air mixture gets compressed when the both the Exhaust port and Transfer ports are covered. The cycle is repeated.


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The major components of a four stroke spark Ignition engine are.

Cylinder: It is a cylindrical vessel in which a piston makes up and down motion.

Piston: It is a cylindrical component making up and down movement in the cylinder.

Combustion Chamber: It is the portion above the cylinder in which the combustion of the Fuel-air mixture takes place.

Inlet and Exhaust ports: The inlet port allows the fresh fuel-air mixture to enter the combustion chamber and the exhaust port discharges the products of combustion.

Crank Shaft: It is a shaft which converts the reciprocating motion of piston into the rotary motion.

Connecting Rod: The connecting rod connects the Piston with the crankshaft.

Cam shaft: The cam shaft controls the opening and closing of inlet and Exhaust valves.

Spark Plug: It is located at the cylinder head. It is used to initiate the combustion process.


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Carburetor

The carburetor in an internal combustion engine is used to regulate and maintain the correct mixture of air and fuel in relation to the engine's load. When an internal

combustion engine ignites its fuel, it creates a high amount of energy in the form of expanding gas and transfers that energy to its specific purpose. Because an internal combustion engine functions by igniting fuel, the correct combination of air and fuel is necessary to create the proper amount of combustion.

The carburetor performs multiple tasks at the same time. It filters the air intake, calculates the necessary ratio of air to fuel based on the engine's load, and distributes the proper amount of fuel to the air stream feeding the engine. By means of a part called the venturi, the carburetor creates an area of lower pressure than atmospheric pressure – commonly known as a vacuum – and uses that pressure differential to meter the fuel into the engine. The carburetor must be designed to negotiate a number of variables, such as the temperature of both the air and the engine, the changes of acceleration, and the difference


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between operating with a partly open throttle and a fully open throttle.

Vaporiser The Vaporiser (also known

as converter) is a device designed to change the fuel from a pressurised liquid to a vapor at around atmospheric pressure for delivery to the

mixer or vapor phase injectors. Because of the refrigerant characteristic of the fuel, heat must be put into the fuel by the converter. This is usually achieved by having engine coolant circulated through a heat exchanger that transfers heat from that coolant to the gaseous fuel.

The Gas Air Mixer is mounted in between the Air Cleaner and the Throttle body and is made up of aluminium. This has a venturi inside which transfers the vacuum signal from the engine to vaporizer. Due to this vacuum the gaseous fuel is delivered to throttle valve inlet where it is mixed with incoming air flow from the air cleaner and delivered to Engine.


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Therefore, modifications on the engine can be summarized as follows;

The air intake of the carburetor is reduced so as to allow more fuel to be injected.

A vaporizer is mounted on the engine so that it can run on gaseous fuels. It is designed to change the fuel from a pressurized liquid to a vapor at around atmospheric pressure for delivery to the mixer or vapor phase injectors. The mixer is the device that mixes the fuel into the air flowing to the engine.

The engine control is performed by the variation of the mixture supply, i.e. the throttle valve position as has been the case with petrol fuel.

The adjustment of the point of ignition in relation to the slow burning velocity of biogas imposes no specific problem as a standard ignition system provides for adjustments in a sufficiently wide range. Engines which cannot operate on unleaded fuel will miss the lubrication effect of condensing lead especially on their exhaust valves. They are therefore subjected to increased wear and tear in gas operation.


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Performance and Operational Parameters

Gas Otto engines when modified from Otto engines using petrol are found to produce less power than in the petrol version. The reason is the decrease in volumetric efficiency as a gaseous fuel occupies a larger portion of the mixture's volume sucked into the engine than liquid fuel and displaces air accordingly. The liquid fuel has a higher volumetric energy content than gas and also cools the air/fuel mixture when evaporating in the intake manifold. The cooling effects an increase in density, and hence the amount of air/fuel mixture actually sucked into the engine on a mass basis is higher.

A gas engine, especially when operating on biogas with a large proportion of useless carbon dioxide, can suck a reduced amount of air only to allow room for the necessary amount of fuel gas. With the decrease in the maximum possible supply of fuel energy or the energy density of the mixture (mixture heating value) the maximum power output consequently decreases in the same proportion. The main effect of the reduction of power is that it needs to be well considered when selecting the power class of an appropriate engine for a given application with a specified power demand. The engine's power and speed control is performed by a variation of the supply of the air/fuel mixture to the engine. This is achieved by the operation of a butterfly valve situated between the actual mixing device and the engine inlet.

The mixing device has to ensure the provision of a constant air/fuel ratio irrespective of the actual amount sucked into the engine, i.e. irrespective of the butterfly valve position. This is achieved by adequate design of the mixing device.


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Alternator Volt ampere - 400 VA

Max output - 500 VA

a.c. voltage - 230 V

Phase - single

Frequency - 50 Hz

Speed - 3000 rpm


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The alternator uses an engine as the prime mover. When the engine is run, it drives the alternator which generates electricity.

It should be noted that the system can give a better performance if a 4 stroke engine was used as the prime mover. The additional requirement of oil supply for lubrication by a 2 stoke engine is highly inconvenient which is eliminated in a 4 stroke engine. 2 stroke engines are comparatively cheap but low in efficiency.

The arrangement discussed in this project cannot be implemented in practice. Biogas has only been de-moisturized and is not free of components like sulphides which can harm the machine components on the long run. Therefore, provisions for the complete purification of the gas are to be added to the current system before it can be practiced.

Generally, biogas consumption of an engine per unit of mechanical power produced, i.e. the specific fuel consumption ranges from 0.5 – 1.0 m³/kWh and is largely dependent ongas quality, temperature, pressure as well as the engine's own efficiency and point of operation.


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PARAMETERS AFFECTING SYSTEM

PERFORMANCEThe following parameters have an influence on the system's

performance:

1) Technical Parameters Biogas production in the biogas plant under consideration of

the plant's size, inputs and operation as well as the reliability of the gas supply system.

Power demand of the driven equipment with regard to its anticipated fluctuation or the anticipated point of continuous operation.

Daily schedule of operation with regard to biogas consumption, plant size and necessary gas storage capacity.

Speed or speed range of the driven machine and the engine. Mode of control, manual or automatic. Local availability of engine service, spare parts, technical

expertise and sufficiently competent operating personnel. Anticipated development of energy supply and demand in

the future.


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2) Economic Parameters Price of biogas plant cum ancillaries. Price of engine cum modification. Price of driven machine and energy distribution system

(electrical wiring, water system, etc.) unless already existing. Operational cost of biogas system, i.e. plant, engine and

driven machine. Cost of the system's service and maintenance. Capital costs (interest rates, pay back periods, etc.). Expected revenue from provision of selling energy or

services, including the use of the engine's waste heat. Savings by the omission of cost for other fuels or forms of

energy. Anticipated development of economic parameters (inflation,

laws, regulations, fuel taxes, etc.).


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MARKETING POSSIBLITIES

BIOTECHBIOTECH–Kerala is a registered non-governmental

organization that started functioning from 1994. The main activities of BIOTECH, from its very inception, include promotion, implementation, training, research and development, and creation of awareness among the people in the field of creation of renewable energy by waste management. Different models of plants for the treatment of waste, according to the requirement of the consumers and the nature of waste, have been developedby BIOTECH..

Kerala’s first biowaste treatment power generation plant was installed eight years ago at Pathanapuram GramPanchayat in the Kollam District. This plant treats 250 kg of

organic waste and generates 3 KW of electric power everyday. After the successful completion of this project, 42 GramPanchayats in Kerala came forward for the installation of such plants. BIOTECH has completed the

installation of the power generation projects using


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market/slaughter house waste with power generation capacities ranging between 3 KW

and 10 KW. The power generated from these projects is being utilized to meet the energy requirements of the concerned markets and the in-house requirement of the plant.

OTHERSAttempts to commercialize the possibilities offered by biogas

electricity generation are being made worldwide. The portable biogas generator or portagas was developed by a group of researchers from the Bureau of Soils and Water Management (BSWM) lead by Dr. Rogelio Concepcion and Dr. Gina Nilo with Mr. Alan Anida, Mr. Carlos Serrano, Ms. Leonora de Leon, and Mr. Victorcito Babiera. The feasibility and development of the portagas were undertaken for five years, from 2001 to 2006.

Similarly, leading establishments including Guascor power, Cat, Siemens, Honda etc. have also started the commercial production of gas generators.


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Biogas generator

CONCLUSION

Biogas is a promising alternative fuel, economic and eco-friendly at the same time. The installation of decentralized biogas plants all over the country would be helpful for the production of biogas, biomanure, electricity apart from the treatment and disposal of waste materials. The importance on the research on alternative fuels has been discussed earlier in this paper. Biogas plants are ideal for this nation and have a lot of potential in energy production which is still untapped. It involves less capital in comparison with other energy projects and the capital can be recovered within a few months of plant installation. Therefore, it is important to spread awareness on the potential benefits of biogas plants among the common people. It is high time that the


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installation of biogas plants is made mandatory for households, hotels and agricultural fields.

“Project Bioelectricity” has been a wonderful experience. The opportunity to interact and learn from experts is invaluable education that transcends the boundaries of a classroom. The exposure and confidence that one gains from such an activity is unmatched. This project, though far from perfect, is as dear to me as a first-born to his mother. The experiences that I went through during the course of its completion have been at times tough and frustrating, but memorable. It was not only a forum for the application of academic knowledge, but also a test of qualities like patience and perseverance.

I conclude that Bioelectricity is a revolutionary concept offering wide scope for research and it should be looked upon as the need of the hour.


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PROJECT ESTIMATE S.N.PARTICULARS AMOUNT

1 Birla Yamaha Generator 75002 Vapouriser 8003 Silica Gel 3504 Generator accessories 8405 LPG rent 1506 Biogas rent 1507 Gas tubes 1008 Spark plug 609 Petrol 150

10 Transport 40011 Labour cost 150012 Mischellaneous expenses 900

TOTAL 12900


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REFERENCE GENERATION OF ELECTRICITY & BIOMANURE by A.

Sajidas,Director,BIOTECH BIOGAS FUEL FOR INTERNAL COMBUSTION ENGINES by N.

Mustafi, R. R. Raine and P. K. BansalDepartment of Mechanical Engineering, The University of Auckland

WATER SCRUBBING: A BETTER OPTION FOR BIOGAS PURIFICATION FOR EFFECTIVE STORAGE by C. Ofori-Boateng and E.M. Kwofie

http://en.wikipedia.org/wiki/biogas http://en.wikipedia.org/wiki/Internal_combustion_engine http://www.seminarprojects.com/Thread-bio-gas-as-

alternative-fuel-in-ic-engines www.ias.ac.in/currsci/jul10/articles13.htm https://sites.google.com/site/engineeringmbaproject/

project-report-on-bio-gas-as-alternate-fuel-in-ic-engine http://link.aip.org/link/abstract/ASMECP/v2004/i37475/

p555/s1


http://link.aip.org/link/abstract/ASMECP/v2004/i37475/p555/s1

http://link.aip.org/link/abstract/ASMECP/v2004/i37475/p555/s1

https://sites.google.com/site/engineeringmbaproject/project-report-on-bio-gas-as-alternate-fuel-in-ic-engine

https://sites.google.com/site/engineeringmbaproject/project-report-on-bio-gas-as-alternate-fuel-in-ic-engine

http://www.ias.ac.in/currsci/jul10/articles13.htm

http://www.seminarprojects.com/Thread-bio-gas-as-alternative-fuel-in-ic-engines

http://www.seminarprojects.com/Thread-bio-gas-as-alternative-fuel-in-ic-engines

http://en.wikipedia.org/wiki/Internal_combustion_engine

http://en.wikipedia.org/wiki/biogas

projct report revised v2.0

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