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Transcript of Bio Gas
Biogas
Photo. Biogas plant
Biogas is very similar to natural gas by properties .
Synonyms for biogas are such words as methane, sewage
gas, marsh gas. Biogas caloric value if from 6000 to 9500
ccal/m3.
Biogas is gas with 50-70% of methane (CH4) and 50-30% of
carbon dioxide (CO2) content. It is produced while
anaerobic decomposition of organic matter and as is a
product of bacteria metabolism. Anaerobic digestion -
the process of organic matter decomposition
Biogas can be
burned in boilers as natural gas;
burned with the purpose of electric and heat power production;
after its treatment up to methane it can be used as fuel for vehicles or fed into the grid like
natural gas.
Substrate Biogas yield m3/t
Cattle manure (natural, 85-88% wet) 60
Pig manure (natural, 85% wet) 65
Chicken dung 80-140
Corn s i lage 180-220
Fresh grass 250
Mi lk whey 50
Gra in 550
Frui t pulp (80% wet) 70
Sugar beet pulp (77% wet) 100
Molasses 430
Sugar beet tops 200
Dis tillery gra in (93% wet) 45
Dis tillery molasses wastewater 50
Brewer’s spent grains (80% wet) 110
Fat 1300
Fat from grease trap 250
Slaughter house waste 300
Root crop vegetables 100
Technical glycerin 500
Fish processing wastes 300
Biogas technology:
Four steps of fermentation
Scheme 1. Metabolism products of the anaerobic fermentation in biogas technology process
Bacteria decompose the organic matter in anaerobic environment. Biogas is an intermediate
product of their metabolism.
The decomposition process can be divided into 4 steps (see scheme 1) each of those accompanied
by different bacteria groups:
In the first stage aerobic bacteria reconstructs high-molecular substances (protein,
carbohydrates, fats, cellulose) by means of enzymes to low-molecular compounds like
monosaccharide, amino acids, fatty acids and water. Enzymes assigned by hydrolysis bacteria
decompose substrate components to small water-soluble molecules. Polymers turn into monomers
(separate molecules). This process called hydrolysis.
Then decomposition is made by acid-forming bacteria. Separate molecules penetrate into
bacteria cells where further transformation takes place. This process is partially accompanied
by anaerobic bacteria that consume rest of oxygen hence providing suitable anaerobic environment
for methane bacteria.
This step produces:
acids (acetic acid, formic acid, butyric acid, propionic acid, caproic acid, lactic acid),
alcohols and ketones (methanol, ethanol, propanol, butanol, glycerin and acetone),
gases (carbon dioxide, carbon, hydrogen sulfide and ammonia).
The step is called oxidation.
Afterwards acid-forming bacteria form initial products for methane formation: acetic acid,
carbon dioxide and hydrogen). These products are formed from organic acids. For vital
functions of these bacteria that consume hydrogen, stable temperature mode is very important.
The last step is methane, carbon dioxide and water formation. 90% of methane yield takes
place at this stage, 70% from acetic acid. Thus acetic acid formation (3rd step) is the factor that
defines the speed of methane formation .
One and two stages biogas technology process
Scheme 2. One and two stages biogas technology process.
In most cases such processes take place simultaneously it means that there is no boundaries for
place and duration of decomposition. Such technology is called two stages technology. For
fermentation of rapidly decomposable raw materials in pure state two stage technology required.
For example chicken dung, distillery slop shouldn’t be recycled in one digester. In order to process
those substrates hydrolysis reactor is needed. Such reactor allows control over the acidity and
alkalinity level in order to avoid bacteria collapse and increase methane yield. (Scheme 2.)
For successful lifecycle of all microorganisms inside the digester special conditions must be secured.
Mandatory factors for that are the following:
Anaerobic environment - active functioning of bacteria is possible only in oxygen-free conditions.
Biogas plant design takes that into consideration.
Humidity - bacteria can live, feed and propagate only in moist conditions.
Temperature - the optimum temperature for mode for all bacteria groups is 35-40о С range. Human
is not able to control this, that is why it is done by automatic control system.
Fermentation period - The quantity of produced biogas is different within the fermentation period.
In the beginning of fermentation it is more intensive then at the en of it. Then comes the moment
when further biomass presence in the digester is economically unfeasible. Our specialists rest upon
long-term experience while calculating fermentation period efficiency.
рН level - hydrolysis and oxidation bacteria can live in acid environment with pH level 4.5-6.3 while
methane and acetic acid formation bacteria can exist only in low alkalinity environment with pH 6.8-
8. All the bacteria kinds have tendency to suspend their activity in case pH level is higher of the
optimum hence the biogas production suspends as well. That is why the best pH level 7 should be
maintained.
Even substrate feed - the by-products of each group of bacteria lifecycle are the nutrients for other
bacteria group. The all work with different speed. The bacteria should not be overfeed as they
hardly be able to produce nutrients for another group. That is why the substrate feed is calculated
and programmed for each project carefully.
Nutrients supply - bacteria provided with all necessary nutrients that are contained in substrate so
the only thing is needed is constant substrate supply. Substrate contains vitamins, soluble ammonia
compounds, microelements and heavy metals in small quantities. Nickel, cobalt, molybdenum,
wolfram and ferrum are required by bacteria for enzyme formation and are also present in
substrates.
Particle size - The smaller the better rule is working here. Bacteria size 1/1000 mm the smaller the
substrate particles the easier the decomposition made by bacteria. Fermentation period becomes
shorter and biogas production faster. If necessary additional substrate disintegration should be done
before substrate feed into reactor.
Mixing - is important not only to avoid floating cork and sediment formation but also for biogas
extraction (mixers help bubbles to go up the digester). Mixers work constantly in a bacteria
preserving mode.
Process stability - microorganisms are used to certain feed other modes.
Any changes should be done smoothly.
Avoid getting into reactor antibiotics, chemical and disinfection means, big quantities of heavy
metals. Our specialists can advice you on that.
The end product of biological treatment are:
biogas (methane not less then 55%, carbon dioxide not more then 45%, hydrogen sulfide
not more then 2%, hydrogen not more then 1%);
Fermented substrate as fermentation residue, consisting of water, cellulose residues, small
quantity of bacteria and organic nutrients (nitrogen, phosphorus, potassium etc.).
Increase of biogas plant efficiency
Photo. Impact of additves application on biogas production
Application of additives in biogas production allows achievement of considerable results at low
expenses. Here are the main advantages of enzymes application:
increase in biogas yield up to 40% without any changes in plant design;
more easy plant operation due to stability of the process;
increase of methane concentration in biogas.
With the purpose of economic viability most of the biogas plants are designed for 70% digestion
efficiency. Thanks to enzymes application it is possible to collect almost complete volume of biogas from
main digesters without post digesting stage.
ZorgEnzym additive is a smashing mixture consisting of enzymes, probiotics and microelements. In case
only enzymes are used, biogas production intensification is often of an accidental character.
When ZorgEnzym is used biogas production increase is guaranteed.
Enzymes – are natural proteins that play key role in plants, animals and human metabolism. These
substances can be called biological catalyst that intensifies organic substance conversion. Main purpose
of enzymes is destruction. Syntheses or integration is done only by three or five percent of existing
enzymes. Such enzymes called anabolic and destructive enzymes are called catabolic. Bacteria and
moulds produce enzymes for destruction of organic substances. Our product is the result of special
technology for combination of different enzymes, which makes it highly efficient biological catalyst.
Application of that product considerably increases biogas plant profitability at expense of higher biogas
yield and intensification of biological feed stock recycling.
Anaerobic digestion process in biogas plant is performed by microorganisms. For optimum biomass
destruction process microorganisms require energy, which can be obtained from polysaccharides, lipids,
and fats. Those substances can be released only after destruction of more complicated substances like
polymers (cellulose, starch).
But natural enzymes quantity is not always enough for optimum microorganism nutrition. With the help
of our product microorganisms constantly receive nutrients in the form of mono and polysaccharides. As
a result reproductive level and biological activity are increased, which leads to considerable reduction of
substrate viscosity and its higher homogeneity. Thanks to that processes biogas production and process
stability can be increased by 30-40%. Accordingly biogas plant energy output is increased.
This additive has been used for 4 years at 80 biogas plants and secures guaranteed 40% biogas yield
increase. There are biogas plants where 260 m3/t biogas yield from corn silage is reached, which is 45%
yield increase.
Price 42 EUR /kg.
Consumption
50-100 grams per 1 ton of organic dry matter or 1-2 grams per 1 kW of installed plant power.
Example
Biogas plant with 60 t/day corn silageloading, 1MW installed electric power.
ODM content 20 t/day.
ZorgEnzyme requirement is 1-2 kg/day.
Additional biogas yield thanks to ZorgEnzyme application will make minimum 3000-4000 m3/day.
Glossary
Alternative energy
Alternative energy – is a sum of prospective methods of energy generation that are not so widespread as conventional energy sources. However they are very interesting due to economical feasibility and
environmental impact.
Anaerobic fermentation
Anaerobic fermentation – is the process of fermentation in anaerobic environment (oxygen free). End
products of such fermentation are methane, carbon dioxide and some other.
Algae recycling
Dear visitor please let us have your definition at [email protected] .
Biogas
Biogas – is gas produced by means of anaerobic fermentation of biomass. Biomass decomposition is
made by methanogenic bacterium. Gas composition: methane 50%-87%, 25%-45% CO2, and some
admixtures. Microorganisms metabolizing carbon from organic substrates in oxygen free conditions (anaerobically). This process is called rotten or oxygen free fermentation, and follows the food chain.
Synonyms for biogas are sewage gas, mine gas, marsh gas, and methane.
Biodiesel
Biodiesel – is fuel made of vegetable or animal fat, and their etherification products.
Biomass
Biomass – is organic substance of biological nature
Biomethane
Biomethane – is produced by means biogas treatment and CO2 extraction from. After such treatment
gas has homogeneous composition containing from 85 to 99% CH4. By composition biomethane is a complete analog of natural gas with only source difference. .
Biological wastes
Biological wastes – slaughterhouse wastes, fat, entrails, blood, ruminant content. Farm wastes: manure. Poultry wastes: chicken dung. Brewery and alcohol plants: distillery slop and brewers’ grains.
Household and factories with biological raw materials wastes.
Biofuel
Biofuel – is fuel made of biological raw materials.
Biogas plant
Biogas plant – produces biogas and bio-fertilizer from biological wastes of agricultural and food
industry by means of anaerobic fermentation.
Bioethanol
Bioethanol – ethanol produced from agricultural raw materials and used as biofuel. Today most part of
bioethanol produced from corn (USA) and sugarcane (Brasil). Cultures with high starch and sugar content like potato or fruits are also can be used as raw materials for bioethanol production
Bone crusher
Bone crusher – is set of mechanisms for crushing cattle and poultry bones for further utilization.
Brewers grains
Brewers’ grains – is a waste product of brewery plant in a form of lees after brewing. Brewers’ grains
contain barn coating and grain kernel parts. Brewers’ grains used for animal feed in dry and fresh state or for biogas production.
Or
Brewers grains – insoluble barley remnants obtained in the process of crushed grains filtration used for water mashing.
Butchering
Butchering – the process of animal killing.
Biogas storage
Biogas storage – biogas storage is made with the help of gasholders.
Biomass energy
Biomass energy – the quantity of energy that can be obtained in the process of biomass recycling.
Clamps
Clamps – piles of manure having round shape.
Cesspit
Cesspit – most primitive sewage storage facility.
Co-generator
Co-generator – is a generator based on gas or diesel engine. It is the source of electrical and heat power. The primary energy source is gas, biogas or diesel fuel. The mane advantage of co-generation
unit to be compared to conventional generators is in its efficiency as co-generator utilizes the heat
that usually is lost.
Co-generation
The process of energy conversion conserved in fuel into heat and electricity.
Compost
Compost – organic fertilizer that is the product of organic matter decomposition by microorganisms.
Composting
Composting – in the process of composting organic biomass is enriched with plant nutrients. Also in the process of composting pathogenic microflora and helminth ages neutralized, the quantity of
cellulose, hemicellulose and pectin substances is reduced, fertilizer becomes more friable that makes it easier for soil injection.
Cutter
Cutter – in sausage production is used for blending and mixing with other components of sausage meat. Cutting mechanism and bowl are fixed at cutter plate. Cutting mechanism equipped with sickle -
shaped and straight knifes.
Chicken dung
Chicken dung - by chemical composition fermented chicken dung refers to the best kinds of organic
fertilizer. Most valuable are chicken and dove dung less valuable duck and goose dung.
Distillery slop (after alcohol production)
Distillery slop – is the waste product of alcohol production. Distillery Slop is a liquid with pale brown
color and grain smell. Dry matter content is 5-15%. Alcohol produced from grain, molasses, fruits, berries, many kinds of potato distillery..
Distillery slop pipeline
Distillery slop pipeline – is piping system for distillery slop transportation to the place of its recycling or filtration fields.
Decanter
Decanter – is a horizontal precipitating screw centrifuge of continuous operation. This is device used
for bio-fertilizer liquid and solid fraction detachment.
Digester
Digester (bioreactor, fermenter) – facility for biological wastes decomposition.
Digester
Digester – is a concrete reservoir with big volume for biological recycling (fermentation) of biomass
with the help of bacteria and other microorganisms in anaerobic environment (oxygen-free).
Distillery plant treatment facilities
Distillery plant treatment facilities – facility complex main function of which cleaning and filtration of
technical water.
Dung extraction
Dung extraction – the analog of manure extraction with the same extraction systems.
Dung storage
Dung storage – special storage for poultry dung storage.
Distillery slop separation
Distillery slop separation – the process of distillery slop liquid and solid fraction division. Liquid fraction
99% of water, solid fraction 70% of water. Separation is used for reduction active organics disposure to filtration fields. In biogas plants separation is also used but for fermented biomass.
Distillery slop dry fodder
Distillery slop dry fodder – solid fraction after distillery slop separation is used as feed for animals. Dry
feed is packed in granules or in bulk. This kind of fodder is suitable for cattle, pigs and poultry.
However this kind of distillery slop utilization is not optimal one.
Distillery slop drying
Distillery slop drying technology comprises 3 stages
1) Solid and liquid fraction division;
2) Evaporation up to 40% of dry matter content; 3) Products 1 and 2 drying (distillery slop drying system).
Dry distillery slop (protein and carbohydrate feed additive included into food of cattle and poultry) is
cooled and sold in bulky state. Distillery slop drying line consumes up to 50% of distillery plant overall
energy consumption.
Excrements
Excrements – organism vital functions waste products that are subject to disposal. Sweat, urine,
faeces, exhalted air are all excrements.
Entrails
Entrails – internals of animal (ingluvies, intestine etc.).
Energy crops
Energy crops – special crops that are used for biogas production. Corn, pilotweed, goat's rue are energy crops.
Energy conservation
Energy conservation – set of measures aimed for efficient electricity and heat usage.
Ethanol
Ethanol – alcohol or spirit. Is a highly inflammable, colorless liquid with characteristic odor. There are two ways of ethanol production, distillery fermentation and ethylene hydration.
Excrements
Excrements – the product of human and animal vital functions and undigested food remnants that are deposited to external environment from distal bowel.
Fodder yeast
Fodder yeast – On basis of undiluted grain distillery slop. Is a natural product obtained from natural raw material by means of alcohol production secondary product synthesis (dry distillery slop). This
kind of distillery slop application is not optimal one.
Feeding meal (tankage)
Feeding meal (tankage) – is compound of animal origin with high protein, fats and amino acids
content. Usage of feeding meal as fodder is prohibited in Europe. Feeding meal production is mostly used for slaughterhouse wastes recycling rather then for valuable fodder production. For feeding meal
production inedible materials like blood, entrails, bones, ruminant content, feather are used. Feeding meal production is highly energy consumptive and economically unfeasible.
Feeding mixture from distillery slop
Protein feeding mixture is based on distillery slop. As fodder yeast feeding mixture is protein source
for animals and poultry. Usage of this nutrients leads to large liver mass of animals and as a result there is no weight increase. Hence it is more feasible to produce energy and bio-fertilizer from those
substrates.
Fodder additives from pulp
Fodder additives from pulp – are fodder additives that are all based on different pulp kinds.
Filtration field
Filtration field - used as mechanical, chemical and biological treatment system. In biological layers
organic matter is decomposed by microorganisms. Filtration field are used for household and food
industry wastes utilization. Many factors should be taken into consideration in the process of filtration field project engineering like soil composition, sanitation zones, municipal requirements and other.
Flotation station
Flotation station – technological units for efficient treatment of sewage water containing so called insoluble substances like fats and cellulose.
Fermenter
Fermenter (bioreactor, digester) – tank in which the process of biogas formation takes place. This process flows with the help of microorganisms.
Filtrate
Filtrate – is a liquid fraction of distillery slop.
Flotation
Flotation – the method of solid particles division. As a rule particles are different substances. Flotation
is possible only for particles surface of which is not completely moisten. It can be achieved by adding small quantities of special substances - flotation agent.
Fruit marc
Fruit marc – fruit press cake.
Filtrate water
Filtrate water – sometimes distillery slop. Filtrate water can jam the pipes, riverbeds etc. Filtrate water has long decomposition period and disposes poison to environment. In past time the problem of
filtrate utilization was very important in the process of distillery or brewery plant waste facility project
engineering. Mostly evaporation technology was used for that. Actually filtrate water contains the whole range of pollutants. Biogas plant equipped with biomass destruction units (cavitators) can solve
the filtrate water problem. In addition enzymes application makes organics content after treatment in biogas plant equal to zero.
Gasholder
Gasholder – big reservoir for storage of natural gas or biogas. Gasholders can be of variable or constant volume; made of steel, rubber or film.
Gas-hydrate
Gas-hydrate – is supramolecular methane and water compound. Gas-hydrate is stable to low temperatures and widespread in nature.
Gas-engine power station
Gas-engine power station – co-generation system based on gas driven engine, which allows
conversion of fuel energy into electricity and heat power.
Gas turbine station
Gas turbine station – is unit based on gas turbine engine. In gas turbine engine gas compressed and
heated then energy of compressed and heated gas converted into mechanic energy of gas turbine
shaft. As opposed to reciprocating motor in gas turbine all processes take place in a gas flow.
Grease trap
Grease trap – used for fat detachment from water.
Hydrogen engine
Hydrogen engine – as an option, engine that use hydrogen as fuel.
Hydropower plant
Hydropower plant - is a complex of hydro technical facilities and equipment for potential water stream
energy conversion into electricity using hydro turbine.
Humus
Humus – is a set of organic compounds in soil but not being a part of life organisms or their remnants
preserving anatomic features. Humus comprises 85-90% of soil organic matter and is crucial for soil productivity evaluation.
Killing department
Killing department – is a facility for cattle slaughter and butchery.
Lagoons
Lagoons – special lakes for waste or manure storage.
Litter (straw or sawdust)
Litter – is a sawdust or straw floor layer in cattle or poultry house.
Landfill gas
Landfill gas – Macrocomponents of landfill gas are methane (CH4) and carbon dioxide (CO2) their correlation can be different accordingly from 40-70% to 30-60%. As microcomponents landfill gas can
contain many other organic compounds.
Manure granulation
Manure granulation – the process of manure drying and and its shaping in a form of small granules.
Mesophilous fermentation
Mesophilous fermentation – is an optimum temperature for methane bacteria germination 30- 40 °С.
This mode of fermentation is most cost effective to be compared to thermophile in terms of heat
power usage.
Methane
Methane – is elementary hydrocarbon, colorless gas without smell, chemical formula CH4. Slightly soluble in water, lighter then air. In industrial and household applications special odorants are added
to give “natural gas” smell.
Methane bacteria
Methane bacteria – bacteria that can obtain energy form the process of CO2 reduction to methane.
Some methane forming bacteria can ferment methyl alcohol and acetic acid at that methane produced
from methyl group carbon.
Methane filling station
Methane filling station – is a filling station equipped with gas filling equipment.
Methane formation
Methane formation – is the process of methane production.
Mortuary
Mortuary – is the place for meat processing industry waste disposal.
Meat processing factory
Meat processing factory – meat processing industry plant.
Manure extraction
Manure extraction – manure removal from cattle house – one of the most laborious processes. Adjusted and proficiently equipped manure extraction process is important for effective cattle
breeding. Manure extraction system efficiency influence to cattle house microclimate, animal health
and local ecological situation.
There are following manure extraction systems. 1. Water wash (humidity 99%) – manure extraction with big water quantity. This method is
characterized by maximum water pollution. Such extraction system implies further settling, aerobic treatment and flotation. Water treatment facilities for that systems consume about 20% of farm
overall energy need.
2. Self-flow (humidity 92-96%). System is made in a such way that manure falls through the slots and flows on inclined floor. Water wash is made periodically.
3. Mechanical (humidity 80-85%). Manure is extracted without water. It is pilled of with an scraper or falls to conveyor belt.
4. Semi-mechanical or manual(humidity 60-70%). In case straw or sawdust litter is used manure
removal is made 2-3 times per month. Litter is added periodically.
Modern farms mostly use self-flow system or it’s combination with mechanical system.
Manure storage
Manure storage – pit, special closed or open container can be used as manure storage.
Manure drying
Manure drying – the process of moisture extraction in drying chamber.
Marc storage
Marc storage – is a special place or building for marc or press cake storage.
Manure storage
Manure storage – is a farm facility for manure collection and storage. The manure storage volume is
defined by the number of cattle, duration of housing season, efficiency of mechanization means and time required for complete manure inactivation for soil injection. Generally the inactivation period
makes 3 years.
Plants tops
Plants tops – leaves of root crops (beet, swede, turnip, carrot, parsnip) and tuberous plants (potato,
topinambour). Used as a secondary product of such crops production.
Poultry factory waste
Poultry factory waste – chicken dung and slaughterhouse waste.
Pellets
Pellets (fuel briskets) – biofuel obtained from waste wood and agricultural wastes. Produced in a form
of granules of standard size.
Pyrolysis
Pyrolysis – is a thermal decomposition of organic matter (wood, oil, coal etc.) without oxygen access.
Pluck
Pluck – eatable internal part of animals (birds, fish, and other).
Press filter
Press filter – equipment that affects filtration with the help of filtration sieve.
Psychrophilic fermentation
Psychrophilic fermentation – the mode which uses temperatures between 8...20 °С.
Power efficiency
Please let us have your definition at [email protected]
Ruminant remnants
Ruminant remnants – content of ingluvies and entrails of butcher consisting of not completely digested fodder remnants. Ruminant content is utilized with other slaughterhouse content as fertilizer or pig
fodder.
Reactor
Reactor – system in active zone of which certain reaction takes place.
Slaughterhouse
Slaughterhouse – place for cattle slaughter
Sugar beet pulp
Sugar beet pulp – extracted chopper of sugar beet, waste product of sugar industry. Used as cattle fodder in dry (in bulk and briquettes) and ensilaged for biogas production.
Straw furnace
Straw furnace – are special furnace that are equipped for straw combustion.
Settling tank (vertical, conical)
Settling tank (vertical, conical) – special equipment for manure liquid and solid fraction division.
Separation
Separation – the process of detachment of heterogeneous compounds of mixtures, liquids with
different density, emulsions, liquid or solid suspended matters in gas or steam.
Solar cell (photovoltaics)
Solar cell – is the generator of renewable energy source that converts solar light to electricity.
Solar panel
Solar panel – sets of solar cells combined into groups.
Treatment facilities (cleaning system)
Treatment facilities (cleaning system) – used for complete or partial purification of industrial water
from pollutants that have negative environment impact.
Termophilic fermentation
Termophilic fermentation – 50 - 55оС the optimum temperature for methane bacteria germination.
Mesophilic fermentation is considered to be more economically attractive due to heating aspect.
Veterinary sanitation factory
Veterinary sanitation factory – other name meat-and-bone powder tankage factory. Such factory
recycles waste products of meat processing factories, slaughterhouses, animal dead bodies, murrain.
Wind power generation
Wind power generation – methods and means for wind energy conversion into mechanical, electrical of
heat energy
Waste utilization and recycling
Waste utilization and recycling – package of measures aimed for ecological safety and wastes
recycling and utilization.
Reference : http://www.zorg-biogas.com/library/biogas