a presentation on bioenergy

8/13/2019 A Presentation on Bioenergy

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B Y

A R T H U R D A N I E L D A D Z I E

M O R G A N J E S S E A S A R E

E S T I B A L I Z B O S I O D O R O

A Presentation on Bioenergy


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Content

IntroductionResources of biomassEnergy Conversion Processesthermal conversionchemical conversion biological or biochemical conversion

BiogasForms of BioenergyEnvironmental and economic impact of bioenergy and biomass


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introduction

The material of plants and animals, including their wastesand residues, is called biomass. It is organic, carbon-based,material that reacts with oxygen in combustion and naturalmetabolic processes to release heat.Such heat, especially if at very high temperatures, may beused to generate work and electricity. The initial materialmay be transformed by chemical and biological processes toproduce biofuels.

Examples of biofuels include methane gas, liquid ethanol,methyl esters, oils and solid charcoal.The term Bioenergy is sometimes used to cover biomass and biofuels together.


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Biomass Resources

Forest and mill residues Agricultural crops and waste Wood wastes

Animal wasteLivestock operation residues Aquatic plantsFast growing trees and plants

Municipal and industrial waste


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Biomass Resources


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Biomass Conversion Processes

Biomass conversion methods can be classified based on; Conversion Technologies and The End products.

Conversion Technologies can be said to be through eitherBiological or biochemical processesChemical processes

Thermal processes.


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Thermal conversion

Thermal conversion processes use heat as the dominantmechanism to convert biomass into another chemical form.The basic alternatives are combustion, torrefaction,pyrolysis, and gasification.

Direct combustion for immediate heat. Dry homogeneousinput is preferred.

They are differentiated principally by the extent to which thechemical reactions involved are allowed to proceed (mainlycontrolled by the availability of oxygen and conversiontemperature).


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Thermal conversion processes contd

The output depends on temperature, type of input materialand treatment process. In some processes the presence of water is necessary andtherefore the material need not be dry. If output ofcombustible gas is the main product, the process is calledgasification.


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Combustion

The oldest and most common method of harnessingenergy from biomass.It is simply the oxidation of wood/plant material to

produce heat.The heat produced can be used directly and it canalso be used for generating electricity. (CHP)


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Gasification

A process that converts organic materials into carbonmonoxide, hydrogen and carbon dioxide and othercombustible gas. Achieved by reacting the material at high temperatures

(>700C), without combustion, with a controlled amountof oxygen and/or steam.The resulting gas mixture is called syngas (fromsynthesis gas or synthetic gas ) or producer gas and isitself a fuel.Syngas may be burned directly in gas engines, used toproduce methanol and hydrogen, or converted intosynthetic fuel.


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Gasification


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Chemical conversion processes

A range of chemical processes may be used to convert biomass into other forms, such as to produce a fuel that ismore conveniently used, transported or stored, or to exploitsome property of the process itself.

Biorefining is the process of "refining" multiple productsfrom biomass as a feedstock or raw material much like apetroleum refinery that is currently in use. A biorefinery is a facility like a petroleum refinery that

comprises the various unit operations and relatedequipment to produce various bioproducts including fuels,power, materials and chemicals from biomass.


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Chemical conversion process contd

By producing multiple products, a biorefinery takesadvantage of the various components in biomass and theirintermediates therefore maximizing the value derived fromthe biomass feedstock. Inset is a biorefinery .


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Biochemical conversion processes

Biochemical or biological conversion makes use of theenzymes of bacteria and other micro-organisms to breakdown biomass.In most cases micro-organisms are used to perform theconversion process: anaerobic digestion, fermentation andcomposting. Another chemical process used in converting straight and waste vegetable oils into biodiesel is transesterification.

Another way of breaking down biomass is by breakingdown the carbohydrates and simple sugars to make alcohol.


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Anaerobic digestion

Anaerobic digestion is a series of processes in whichmicroorganisms break down biodegradable material in theabsence of oxygen.It is used for industrial or domestic purposes to manage waste and/or to release energy. Much of the fermentation used industrially to produce foodand drink products, as well as home fermentation, usesanaerobic digestion. Silage is produced by anaerobic

digestion .


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Anaerobic digestion contd

Many microorganisms are involved in the process ofanaerobic digestion. These organisms feed upon the initialfeedstock, which undergoes a number of differentprocesses, converting it to intermediate molecules,

including sugars, hydrogen, and acetic acid, before finally being converted to biogas.Feedstocks can include biodegradable waste materials, suchas waste paper, grass clippings, leftover food, sewage, and

animal waste.The three principal products of anaerobic digestion are biogas, digestate, and water


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Anaerobic digestion


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Summary of conversion processes

Biological conversion:- Anaerobic DigestionFermentation

Thermal conversion:- CombustionGasificationPyrolysis

Chemical conversion:- Bio-refining.


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Forms of Bioenergy

Bioenergy may exist in different forms. These are mainly;BiopowerHeat

BiofuelsCombined heat and power (co-generation)


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Biopower

Biopower is electricity generated from combustion of biomass, either alone or in combination with coal,natural gas or other fuel (termed co-firing). Most biopower plants are direct-fired systems. That is,

biomass feedstock are burned in a boiler to producehigh-pressure steam which runs turbines connected toelectric generators.The electricity produced can be distributed for industrial,residential or commercial use. The steam generated from combustion of biomassfeedstock can also be used directly power mechanicalprocesses in industrial settings


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Heat

Processes like combustion, pyrolysis and gasificationproduce heat in large quantities which is harnessed.

Gasifiers offer a flexible option for thermal applications, asthey can be retrofitted into existing gas fueled devices suchas ovens, furnaces, boilers, etc., where syngas may replacefossil fuels.


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Biofuels

Biofuel is liquid, gas and solid fuels produced from twotypes of biomass materials plant sugars and starches(e.g., grains), and lignocellulosic materials (e.g., leaves,stems and stalks).

Liquid and gas biofuels are produced through fermentation,gasification, pyrolysis, torrefaction, and transesterificationconversion technologies. The primary use of liquid and gas biofuels is transportation

They include ethanol, biodiesel, syngas, biogas, methanol,char and bio-coal and bioethers.


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Combined heat and power.

Combined heat and power (CHP), also known as co-generation, is the simultaneous production of electricityand heat from a single fuel source, including biomass.In a gas turbine CHP plant, hot exhaust gases from thecombustion process are captured in a heat recovery unitand used to heat steam which is then used in heating andcooling of various indoor environments. In steam boiler CHP plants steam is produced that runs

electric generators and for heating/cooling.


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Environmental impact

Using biomass as a fuel produces air pollution in the form ofcarbon monoxide, carbon dioxide, NOx (nitrogen oxides), VOCs (volatile organic compounds), particulates and otherpollutants, in some cases at levels above those from

traditional fuels.Biomass systems can reduce waste energy from 66% to 25%compared to traditional fossil fuels, meaning a significantlysmaller amount of input material (biomass) is used,

therefore having a positive effect on the global environmentand use of fuel.


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Environmental impact contd

Modern biomass systems use filters. These filters capturecarbon and other pollutants before they enter theatmosphere. Thus in the biomass lifecycle, the pollutantsare captured by trees and crops, they are burnt, pollutants

are captured and less are released back into theenvironment. Any pollutants released are then reabsorbed by trees and plants


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Economic impact

In combination with a significant energy efficiency effort,there is almost nothing better for the local economy thanincreased reliance on biomass fuels. From amacroeconomic perspective, there are three different

engines that can be applied to drive local economicdevelopment;Economic growth through business expansion (earnings) oremployment

Import substitution; andEfficiency improvement


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Pricing of biomass against production


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BENEFITS

The biomass material acquisition is comparatively cheaper.Biomass is environmentally friendly compared to fossilfuelsBiomass can be sourced locally.The use of biomass fuel provides an economic incentive tomanage woodland which improves biodiversity.In rural economic development and stability: we spend billions of dollars each year importing oil, biomass couldreplace half of this and direct the rest to other sectors


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Conclusion

Biomass provides low CO2 emissions, heat andpower. like other renewable energy sources, good planning

and managing will give higher efficiency. Systems for it use are still under-development andimproved utilisation of biomass is expected.Considering the benefits mentioned above; biomassis a promising source of renewable energy anddeveloping it should be a key issue.


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References

www.bioenergyconsult.com/tag/biomass-combustion-process/http//en.wikipedia.org/wiki/gasifier

http//en.wikipedia.org/wiki/biomasshttp://www.biomassenergycentre.org.ukhttp//en.wikipedia.org/wiki/anaerobic digestion.http//www.wgbn.wisc.edu/http//en.wikipedia.org/wikihttp//en.wikipedia.org/Biomass_heating_system

a presentation on bioenergy

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