WOOD & WASTE GASIFIRE WOOD & WASTE GASIFIRE SYSTEMSYSTEM

Department of Mechanical Engineering

M.L.V.T.E.C., BHILWARA

SUBMITTED TO:

Mr. Ajit kumar joshi

HOD(Mechanical)

PRESENTED BY:ARVIND GAUTAM

10EMBME011

PERSENTED TOPICPERSENTED TOPIC INTRODUCTIONINTRODUCTION WOODGASWOODGAS GASIFICATIONGASIFICATION HISTORY OF GASIFICATIONHISTORY OF GASIFICATION WOOD GAS COMPONENTWOOD GAS COMPONENT CONSTUCTION DETAIL OF GASIFIER CONSTUCTION DETAIL OF GASIFIER

SYSTEMSYSTEM PYROLYSIS OF COALPYROLYSIS OF COAL GAS PRODUCERS(GASIFIRE)GAS PRODUCERS(GASIFIRE)

FILTER UNIT FILTER UNIT CYCLONE SYSTEMCYCLONE SYSTEM COOLING UNITCOOLING UNIT APPLICATION OF WOODGAS SYSTEMAPPLICATION OF WOODGAS SYSTEM ADVANTAGESADVANTAGES DISADVANTAGESDISADVANTAGES

INTRODUCTIONINTRODUCTION

Wood gas:- Wood gas:- is a is a syngas fuel which can be used as a fuel for furnaces, fuel which can be used as a fuel for furnaces, stoves and vehicles in place of stoves and vehicles in place of petrol, , diesel or other fuels. During the or other fuels. During the production process production process biomass or other carbon-containing materials is or other carbon-containing materials is gasified within the oxygen-limited environment of a within the oxygen-limited environment of a wood gas generator to to produce produce hydrogen and and carbon monoxide. These gases can then be burnt . These gases can then be burnt as a fuel within an oxygen rich environment to produce as a fuel within an oxygen rich environment to produce carbon dioxide, , water and heat. In some gasifiers this process is preceded by and heat. In some gasifiers this process is preceded by pyrolysis, , where the biomass or coal is first converted to where the biomass or coal is first converted to char, releasing , releasing methane and and tar rich in rich in polycyclic aromatic hydrocarbons..

composition by volume which most likely is also variable:composition by volume which most likely is also variable:Nitrogen N N22: 50.9%: 50.9%Carbon monoxide CO: 27.0%Carbon monoxide CO: 27.0%Hydrogen H H22: 14.0%: 14.0%Carbon dioxide COCarbon dioxide CO22: 4.5%: 4.5%Methane CH CH44: 3.0%: 3.0%Oxygen O O22: 0.6%.: 0.6%.

GASIFICATIONGASIFICATION

A A wood gas generatorwood gas generator is a is a gasification unit unit which converts timber or which converts timber or charcoal into into wood gas, , a a syngas consisting of consisting of atmospheric nitrogen, , carbon monoxide, , hydrogen, traces of , traces of methane, , and other gases, and other gases, whichwhich - after cooling and filtering - after cooling and filtering - can then be used to power an - can then be used to power an internal combustion engine or for other purposes. or for other purposes. Historically wood gas generators were often Historically wood gas generators were often mounted on mounted on vehicles, but present studies and , but present studies and developments concentrate mostly on stationary developments concentrate mostly on stationary plantsplants

HISTORY OF GASIFICATIONHISTORY OF GASIFICATION

had been an important and common technology which was widely used to generate had been an important and common technology which was widely used to generate Town gas from coal mainly for lighting purposes during the 19th and early 20th century. from coal mainly for lighting purposes during the 19th and early 20th century. When the first stationary When the first stationary internal combustion engines based on the based on the Otto cycle became became

available in the 1870s, they began displacing steam engines as prime movers in many works available in the 1870s, they began displacing steam engines as prime movers in many works requiring stationary motive power. Adoption accelerated after the Otto engine's requiring stationary motive power. Adoption accelerated after the Otto engine's patent

expired in 1886. The potential and practical applicability of gasification to expired in 1886. The potential and practical applicability of gasification to internal combustion engines were well-understood from the earliest days of their were well-understood from the earliest days of their

development.development.

In 1873, In 1873, Thaddeus S. C. Lowe developed and patented the water gas process by which large developed and patented the water gas process by which large amounts of amounts of hydrogen gas could be generated for residential and commercial use in heating gas could be generated for residential and commercial use in heating and lighting. Unlike the common coal gas, or coke gas which was used in municipal service, and lighting. Unlike the common coal gas, or coke gas which was used in municipal service,

this gas provided a more efficient heating fuel.this gas provided a more efficient heating fuel.

During the late 19th century internal combustion engines were sometimes fueled by During the late 19th century internal combustion engines were sometimes fueled by town gas, and during the early 20th century many stationary engines switched to using , and during the early 20th century many stationary engines switched to using

producer gas created from created from coke which was substantially cheaper than town gas which was which was substantially cheaper than town gas which was based on the distillation (pyrolysis) of more expensive coal.based on the distillation (pyrolysis) of more expensive coal.

In about 1920 In about 1920 French inventor inventor Georges Imbert created the "Imbert" downdraft generator. created the "Imbert" downdraft generator.

During During World War II gasoline was rationed and in short supply in Great Britain, United States was rationed and in short supply in Great Britain, United States and Germany large numbers of such generators were constructed or even improvised to and Germany large numbers of such generators were constructed or even improvised to convert wood and coal into fuel for vehicles. Commercial generators were in production convert wood and coal into fuel for vehicles. Commercial generators were in production

before and after the war for use in special circumstances or in before and after the war for use in special circumstances or in distressed economies..

Wood gas engine componentWood gas engine component

1. gasifies unit 2. cooling unit 3. filter unit1. gasifies unit 2. cooling unit 3. filter unit

GasificationGasification The actual gasification happen at temperatures above 700C when The actual gasification happen at temperatures above 700C when

the glowing coke is allowed to react with a the glowing coke is allowed to react with a GASIFICATION AGENTGASIFICATION AGENT such as oxygen, air or steam. The coke is gradually broken down such as oxygen, air or steam. The coke is gradually broken down into gases such as CO, CO2 and H2 (from the steam reaction)into gases such as CO, CO2 and H2 (from the steam reaction)

PYROLYSIS PYROLYSIS After drying, the first process that the fuel is going though After drying, the first process that the fuel is going though

during heating is the during heating is the PYROLYSISPYROLYSIS, which initiate at around , which initiate at around 230C. During pyrolysis thermally unstable components such 230C. During pyrolysis thermally unstable components such as lignine in biomass are broken down and evaporate with as lignine in biomass are broken down and evaporate with other volatile components. The resulting other volatile components. The resulting PYROLYSIS GASPYROLYSIS GAS consist mainly of tar, polycyclic aromatic hydrocarbons consist mainly of tar, polycyclic aromatic hydrocarbons (PAH), methane (CH4), steam and CO2. The solid residual is (PAH), methane (CH4), steam and CO2. The solid residual is carbon structures (carbon structures (COKECOKE) and ashes. ) and ashes.

Gas Producers (Gasifiers) Gas Producers (Gasifiers) Design of gasifier depends upon type of fuel used and whether gasifier is Design of gasifier depends upon type of fuel used and whether gasifier is

portable or stationary. Gas producers are classified according to how the portable or stationary. Gas producers are classified according to how the air blast is introduced in the fuel column. History of gasification reveals air blast is introduced in the fuel column. History of gasification reveals serveral designs of gasifiers. serveral designs of gasifiers.

The most commonly built gasifiers are classied as The most commonly built gasifiers are classied as

UPDRAFT GAS PRODUCER DOWNDRAFT GAS PRODUCER TWIN-FIRE GAS PRODUCER CROSSDRAFT GAS PRODUCER CROSSDRAFT GAS PRODUCER

UPDRAFT GAS PRODUCER UPDRAFT GAS PRODUCER An updraft gasifier has clearly An updraft gasifier has clearly

defined zones for partial defined zones for partial combustion, reduction, and combustion, reduction, and pyrolysis. Air is introduced at the pyrolysis. Air is introduced at the bottom and act as bottom and act as countercurrent to fuel flow. The countercurrent to fuel flow. The gas is drawn at higher location. gas is drawn at higher location. The updraft gasifier achieves the The updraft gasifier achieves the highest efficiecy as the hot gas highest efficiecy as the hot gas passes through fuel bed and passes through fuel bed and leaves the gasifier at low leaves the gasifier at low temperature. The sensible heat temperature. The sensible heat given by gas is used to preheat given by gas is used to preheat and dry fuel. Disadvantages of and dry fuel. Disadvantages of updraft gas proucer are updraft gas proucer are excessive amount of tar in raw excessive amount of tar in raw gas and poor loading capability. gas and poor loading capability. Hence it is not suitable for Hence it is not suitable for

running vehiclerunning vehicle..

DOWNDRAFT GAS PRODUCER DOWNDRAFT GAS PRODUCER In the updraft gasifier, gas leaves In the updraft gasifier, gas leaves

the gasifier with high tar vapour the gasifier with high tar vapour which may seriously interfer the which may seriously interfer the operation of internal combustion operation of internal combustion engine. This problem is minimized in engine. This problem is minimized in downdraft gasifier. In this type, air is downdraft gasifier. In this type, air is introduced into downward flowing introduced into downward flowing packed bed or solid fuels and gas is packed bed or solid fuels and gas is drawn off at the bottom. A lower drawn off at the bottom. A lower overall efficiency and difficulties in overall efficiency and difficulties in handling higher moisture and ash handling higher moisture and ash content are common problems in content are common problems in small downdraft gas producers. The small downdraft gas producers. The time (20-30 minutes) needed to time (20-30 minutes) needed to ignite and bring plant to working ignite and bring plant to working temperature with good gas quality is temperature with good gas quality is shorter than updraft gas producer. shorter than updraft gas producer. This gasifier is preferred to updraft This gasifier is preferred to updraft gasifier for internal combustion gasifier for internal combustion enginesengines

TWIN-FIRE GAS PRODUCER TWIN-FIRE GAS PRODUCER current and counter-current current and counter-current

gasifiers are combined in a so a gasifiers are combined in a so a called twin-fire gasifier. It called twin-fire gasifier. It consists of two defined reaction consists of two defined reaction zones. Drying, low-temperature zones. Drying, low-temperature carbonisation, and cracking of carbonisation, and cracking of gases occur in the upper zone, gases occur in the upper zone, while permanent gasification of while permanent gasification of charcoal takes in lower zone. charcoal takes in lower zone. The gas temperature lies The gas temperature lies between 460 to 520between 460 to 520 o o C. Total C. Total process takes place with under process takes place with under pressure of -30 mbar. Twin-fire pressure of -30 mbar. Twin-fire gasifier produces fairly clean gasifier produces fairly clean gas.gas.

CROSSDRAFT GAS PRODUCER CROSSDRAFT GAS PRODUCER gas producers, although they have certain gas producers, although they have certain

advantages over updraft and downdraft advantages over updraft and downdraft gasifiers, they are not of ideal type. The gasifiers, they are not of ideal type. The disadvantages such as high exit gas disadvantages such as high exit gas temperature, poor COtemperature, poor CO 2 2 reduction and high reduction and high gas velocity are the consequence of the gas velocity are the consequence of the design. Unlike downdraft and updraft design. Unlike downdraft and updraft gasifiers, the ash bin, fire and reduction gasifiers, the ash bin, fire and reduction zone in crossdraft gasifiers are separated. zone in crossdraft gasifiers are separated. This design characteristics limit the type of This design characteristics limit the type of fuel for operation to low ash fuels such as fuel for operation to low ash fuels such as wood, charcoal and coke. The load following wood, charcoal and coke. The load following ability of crossdraft gasifier is quite good ability of crossdraft gasifier is quite good due to concentrated partial zones which due to concentrated partial zones which operates at temperatures up to 2000 operates at temperatures up to 2000 o o c. c. Start up time (5-10 minutes) is much faster Start up time (5-10 minutes) is much faster than that of downdraft and updraft units. than that of downdraft and updraft units. The relatively higher temperature in cross The relatively higher temperature in cross draft gas producer has an obvious effect on draft gas producer has an obvious effect on gas composition such as high carbon gas composition such as high carbon monoxide, and low hydrogen and methane monoxide, and low hydrogen and methane content when dry fuel such as charcoal is content when dry fuel such as charcoal is used. Crossdraft gasifier operates well on used. Crossdraft gasifier operates well on dry air blast and dry fueldry air blast and dry fuel

Application of wood gas engineApplication of wood gas engine

1.PRODUCTION OF MECHANICAL OR ELECTRICAL POWER IN 1.PRODUCTION OF MECHANICAL OR ELECTRICAL POWER IN STATIONARY INSTALLATIONSSTATIONARY INSTALLATIONS

Gasifiers connected to stationary engines offer the possibility of Gasifiers connected to stationary engines offer the possibility of using biomass to generate mechanical or electrical power in the using biomass to generate mechanical or electrical power in the range from a few kW up to a few MW. range from a few kW up to a few MW.

Producer gas of engine quality needs a sufficiently high heating Producer gas of engine quality needs a sufficiently high heating value (above 4200 Kj/m³ ), must be virtually tar and dust free in value (above 4200 Kj/m³ ), must be virtually tar and dust free in order to minimize engine wear, and should be as cool as possible order to minimize engine wear, and should be as cool as possible in order to maximize the engine's gas intake and power output. in order to maximize the engine's gas intake and power output.

2. MOBILE APPLICATIONS2. MOBILE APPLICATIONS The use of down-draught gasifiers fuelled by wood or charcoal to The use of down-draught gasifiers fuelled by wood or charcoal to

power cars, lorries, buses, trains, boats and ships power cars, lorries, buses, trains, boats and ships This technique is currently being studied for powering of tractors This technique is currently being studied for powering of tractors

Applications on trains and boats suffer less from weight and load Applications on trains and boats suffer less from weight and load

constraints, and for this reason give better resultsconstraints, and for this reason give better results

AdvantagesAdvantages Wood gas generators have a number of advantages over use of petroleum Wood gas generators have a number of advantages over use of petroleum

fuels:fuels: They can be used to run internal-combustion engines (or even gas They can be used to run internal-combustion engines (or even gas

turbines, for maximal efficiency) using wood, a renewable resource, and in turbines, for maximal efficiency) using wood, a renewable resource, and in the absence of petroleum or natural gas, for example, during a fuel the absence of petroleum or natural gas, for example, during a fuel shortage.shortage.

They have a closed carbon cycle, contribute less to global warming, and They have a closed carbon cycle, contribute less to global warming, and are sustainable in nature.are sustainable in nature.

They can be relatively easily fabricated in a crisis using materials on hand.They can be relatively easily fabricated in a crisis using materials on hand. They are far cleaner burning than, say, a wood fire or even a gasoline-They are far cleaner burning than, say, a wood fire or even a gasoline-

powered engine is (without emissions controls), producing little if any powered engine is (without emissions controls), producing little if any soot.soot.

When used in a stationary design, they reach their true potential, as they When used in a stationary design, they reach their true potential, as they are feasible to use in small combined heat and power scenarios (with heat are feasible to use in small combined heat and power scenarios (with heat recovery from the wood gas producer, and possibly the engine/generator, recovery from the wood gas producer, and possibly the engine/generator, for example, to heat water for hydronic heating), even in industrialized for example, to heat water for hydronic heating), even in industrialized countries, even during good economic times, provided that a sufficient countries, even during good economic times, provided that a sufficient supply of wood is attainable. Larger-scale installations can reap even supply of wood is attainable. Larger-scale installations can reap even better efficiencies, and are useful for district heating as wellbetter efficiencies, and are useful for district heating as well

DisadvantagesDisadvantages

The disadvantages of wood gas generators are:The disadvantages of wood gas generators are: the large specific sizethe large specific size the relatively slow starting speed; the time to heat the the relatively slow starting speed; the time to heat the

initially cold batch of wood to the necessary temperature initially cold batch of wood to the necessary temperature level can take many minutes and in bigger plants even level can take many minutes and in bigger plants even hours until the designed power is reached.hours until the designed power is reached.

a batch burning operation, that some designs feature, and a batch burning operation, that some designs feature, and that regularly interrupts the gas producing process.that regularly interrupts the gas producing process.

the stop operation out of a high load level is difficult (for the stop operation out of a high load level is difficult (for example the stop of the engine using the gas): the residual example the stop of the engine using the gas): the residual heat still produces gas, which for a certain time leaves the heat still produces gas, which for a certain time leaves the gasifier either without control, or has to be used in a burnergasifier either without control, or has to be used in a burner

the primary combustible fuel-gas produced during gasification is the primary combustible fuel-gas produced during gasification is carbon monoxide: it is an intentional fuel-product, and is carbon monoxide: it is an intentional fuel-product, and is subsequently burned to safe carbon dioxide in the engine (or other subsequently burned to safe carbon dioxide in the engine (or other application) along with the other fuel-gases; however, continuous application) along with the other fuel-gases; however, continuous exposure to carbon-monoxide can be fatal to humans even in exposure to carbon-monoxide can be fatal to humans even in small to moderate concentrations.small to moderate concentrations.

the humidity of the wood (usually 15 to 20%) and the water vapor the humidity of the wood (usually 15 to 20%) and the water vapor created by the O- and H-atoms of the dry wood itself (about 0.4 created by the O- and H-atoms of the dry wood itself (about 0.4 liters of water loaded with organic substances per kg of dry wood) liters of water loaded with organic substances per kg of dry wood) condenses during the gas cooling and filtering procedure and condenses during the gas cooling and filtering procedure and yields a liquid (see also wood tar), which needs specific waste yields a liquid (see also wood tar), which needs specific waste water treatment. This treatment requires about 25 to 35 % of the water treatment. This treatment requires about 25 to 35 % of the created wood gas energy.created wood gas energy.

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