Biogas Basics - Revision history

Ranisha at 11:19, 19 September 2018

2018-09-19T11:19:42Z

Ranisha: /* Overview */

2018-09-19T11:19:30Z

Overview

Dumisani J Nxumalo: /* Composition and Properties of Biogas */

2016-10-04T12:57:23Z

Composition and Properties of Biogas

Ranisha at 13:21, 29 July 2016

2016-07-29T13:21:47Z

Ranisha: /* Anaerobic Fermentation */

2016-07-29T13:21:14Z

Anaerobic Fermentation

Ranisha: /* Anaerobic Fermentation */

2015-06-01T08:25:11Z

Anaerobic Fermentation

Ranisha: /* Overview */

2015-04-28T07:03:52Z

Overview

Ranisha: /* Overview */

2015-04-28T06:57:54Z

Overview

Ranisha at 06:48, 28 April 2015

2015-04-28T06:48:06Z

Ranisha: /* Overview */

2015-04-28T06:46:10Z

Overview

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 [[Portal:Biogas|►Back to Biogas Portal]]
 = Overview =
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 <references />
 [[Category:Impacts]]

← Older revision		Revision as of 11:19, 19 September 2018
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	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 utilized 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 is a renewable fuel and electricity produced from it can be used to attract renewable energy subsidies in some parts of the world.		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 utilized 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 is a renewable fuel and electricity produced from it can be used to attract renewable energy subsidies in some parts of the world.
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		+	Below is the biogas equivalent to different fuels<ref name="https://energypedia.info/images/2/2e/Biogas_Technology.pdf">https://energypedia.info/images/2/2e/Biogas_Technology.pdf</ref>:
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		+	*1 Kg firewood => 0.2 m³ biogas
		+	*1 Kg dried cow dung => 0.1 m³ biogas
		+	*1 Kg Charcoal => 0.5 m³ biogas
		+	*1 Litre Kerosine => 2.0 m³ biogas

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 In practical fermentation processes the metabolic actions of various bacteria all act in concert. No single bacteria is able to produce fermentation products alone.
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-{| border="1" style="width: 100%" class="wikitable FCK__ShowTableBorders"
+{| class="wikitable FCK__ShowTableBorders" style="width: 100%;" border="1"
 |-
-| style="background: rgb(180, 238, 180); width: 50%; text-align: center" | '''Component'''
+| style="background: rgb(180, 238, 180); width: 50%; text-align: center;" | '''Component'''
-| style="background: rgb(180, 238, 180); text-align: center" | '''Content [%]'''
+| style="background: rgb(180, 238, 180); text-align: center;" | '''Content [%]'''
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 | Methane, CH<sub>4</sub>
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-The '''calorific value''' of biogas is about 6 kWh/m<sup>3</sup> - this corresponds to about half a litre of diesel oil. The net calorific value depends on the efficiency of the [[Biogas_Appliances#Two-flame_Burners|burners]]&nbsp;or [[Biogas_Appliances|appliances]]. Methane is the valuable component under the aspect of using biogas as a fuel.
+The '''calorific value''' of biogas is about 6 kWh/m<sup>3</sup> - this corresponds to about half a litre of diesel oil. The net calorific value depends on the efficiency of the [[Biogas Appliances#Two-flame Burners|burners]]&nbsp;or [[Biogas Appliances|appliances]]. Methane is the valuable component under the aspect of using biogas as a fuel.
 <br/>
 = Substrate and Material Balance =

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 *macro-economical benefits through decentralized energy generation, import substitution and environmental protection
-Thus, biogas technology can substancially [[Biogas_Technology_for_Development|contribute to conservation and development]], if the concrete [[Biogas_Framework|conditions are favorable]]. However, the required high investment capital and other [[Limitations_of_Biogas_Technology|limitations of biogas technology]] should be thoroughly considered.
+Thus, biogas technology can substantially [[Biogas_Technology_for_Development|contribute to conservation and development]], if the concrete [[Biogas_Framework|conditions are favorable]]. However, the required high investment capital and other [[Limitations_of_Biogas_Technology|limitations of biogas technology]] should be thoroughly considered.
 ► Also see: [[Biogas_-_Costs_and_Benefits|Biogas - Costs and Benefits]]
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 In developing countries, there is a direct link between the problem of fertilization and progressive [[Environmental_Frame_Conditions_of_Biogas_Technology|deforestation due to high demand for firewood]]. In many rural areas, most of the inhabitants are dependant on dung and organic residue as fuel for cooking and heating. Such is the case, for example, in the treeless regions of India (Ganges plains, central highlands), Nepal and other countries of Asia, as well as in the Andes Mountains of South America and wide expanses of the African Continent. According to data published by the FAO, some 78 million tons of cow dung and 39 million tons of phytogenic waste were burned in India alone in 1970. That amounts to approximately 35% of India's total noncommercial/nonconventional energy consumption.
-The burning of dung and plant residue is a considerable waste of plant nutrients. Farmers in developing countries are in dire need of fertilizer for maintaining cropland productivity. Nonetheless, many small farmers continue to burn potentially valuable fertilizers, even though they cannot afford to buy chemical fertilizers. At the same time, the amount of technically available nitrogen, pottasium and phosphorous in the form of organic materials is around eight times as high as the quantity of chemical fertilizers actually consumed in developing countries. Especially for small farmers, biogas technology is a suitable tool for making maximum use of scarce resources: After extraction of the energy content of dung and other organic waste material, the resulting sludge is still a good [[Organic_Fertilizer_from_Biogas_Plants|fertilizer]], supporting general soil quality as well as higher crop yields.
+The burning of dung and plant residue is a considerable waste of plant nutrients. Farmers in developing countries are in dire need of fertilizer for maintaining cropland productivity. Nonetheless, many small farmers continue to burn potentially valuable fertilizers, even though they cannot afford to buy chemical fertilizers. At the same time, the amount of technically available nitrogen, potassium and phosphorous in the form of organic materials is around eight times as high as the quantity of chemical fertilizers actually consumed in developing countries. Especially for small farmers, biogas technology is a suitable tool for making maximum use of scarce resources: After extraction of the energy content of dung and other organic waste material, the resulting sludge is still a good [[Organic_Fertilizer_from_Biogas_Plants|fertilizer]], supporting general soil quality as well as higher crop yields.
 ► Also see: [[Organic_Fertilizer_from_Biogas_Plants|Organic Fertilizer from Biogas Plants]]
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 <references />
 [[Category:Biogas]]

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 = Anaerobic Fermentation =
-Knowledge of the fundamental processes involved in methane fermentation is necessary for planning, building and operating biogas plants. [[Anaerobic methods waste treatment|Anaerobic fermentation]] involves the activities of three different bacterial communities. The process of biogas-production depends on [[Parameters and Process Optimisation for Biogas|various parameters]]. For example, changes in ambient temperature can have a negative effect on bacterial activity.
+Knowledge of the fundamental processes involved in methane fermentation is necessary for planning, building and operating biogas plants. [[Anaerobic Methods of Waste Treatment|Anaerobic fermentation]] involves the activities of three different bacterial communities. The process of biogas-production depends on [[Parameters and Process Optimisation for Biogas|various parameters]]. For example, changes in ambient temperature can have a negative effect on bacterial activity.
-Biogas microbes consist of a large group of complex and differently acting microbe species, notable the methane-producing bacteria. The whole biogas-process can be devided into three steps: hydrolysis, acidification, and methane formation. Three types of bacteria are involved.
+Biogas microbes consist of a large group of complex and differently acting microbe species, notably the methane-producing bacteria. The whole biogas-process can be divided into three steps: hydrolysis, acidification, and methane formation. Three types of bacteria are involved.
 {| cellspacing="0" cellpadding="0" border="0" class="IMGcenter"
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 == Hydrolysis ==
-In the first step (hydrolisis), the organic matter is enzymolyzed externally by extracellular enzymes (cellulase, amylase, protease and lipase) of microorganisms. Bacteria decompose the long chains of the complex carbohydrates, proteins and lipids into shorter parts. For example, polysaccharides are converted into monosaccharides. Proteins are split into peptides and amino acids.
+In the first step (hydrolysis), the organic matter is enzymolyzed externally by extracellular enzymes (cellulase, amylase, protease and lipase) of microorganisms. Bacteria decompose the long chains of the complex carbohydrates, proteins and lipids into shorter parts. For example, polysaccharides are converted into monosaccharides. Proteins are split into peptides and amino acids.
 <br/>
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 |}
-Methane-producing bacteria, involved in the third step, decompose compounds with a low molecular weight. For example, they utilize hydrogen, carbon dioxide and acetic acid to form methane and carbon dioxide. Under natural conditions, methane producing microorganisms occur to the extent that anaerobic conditions are provided, e.g. under water (for exemple in marine sediments), in ruminant stomaches and in marshes. They are obligatory anaerobic and very sensitive to environmental changes. In contrast to the acidogenic and acetogenic bacteria, the methanogenic bacteria belong to the archaebacter genus, i.e. to a group of bacteria with a very heterogeneous morphology and a number of common biochemical and molecular-biological properties that distinguish them from all other bacterial general. The main difference lies in the makeup of the bacteria's cell walls.
+Methane-producing bacteria, involved in the third step, decompose compounds with a low molecular weight. For example, they utilize hydrogen, carbon dioxide and acetic acid to form methane and carbon dioxide. Under natural conditions, methane producing microorganisms occur to the extent that anaerobic conditions are provided, e.g. under water (for example in marine sediments), in ruminant stomachs and in marshes. They are obligatory anaerobic and very sensitive to environmental changes. In contrast to the acidogenic and acetogenic bacteria, the methanogenic bacteria belong to the archaebacter genus, i.e. to a group of bacteria with a very heterogeneous morphology and a number of common biochemical and molecular-biological properties that distinguish them from all other bacterial general. The main difference lies in the makeup of the bacteria's cell walls.
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 == Symbiosis of Bacteria ==
-Methane- and acid-producing bacteria act in a symbiotical way. On the one hand, acid-producing bacteria create an atmosphere with ideal parameters for methane-producing bacteria (anaerobic conditions, compounds with a low molecular weight). On the other hand, methane-producing microorganisms use the intermediates of the acid-producing bacteria. Without consuming them, toxic conditions for the acid-producing microorganisms would develop.
+Methane- and acid-producing bacteria act in a symbiotic way. On the one hand, acid-producing bacteria create an atmosphere with ideal parameters for methane-producing bacteria (anaerobic conditions, compounds with a low molecular weight). On the other hand, methane-producing microorganisms use the intermediates of the acid-producing bacteria. Without consuming them, toxic conditions for the acid-producing microorganisms would develop.
 In practical fermentation processes the metabolic actions of various bacteria all act in concert. No single bacteria is able to produce fermentation products alone.

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 = Anaerobic Fermentation =
-Knowledge of the fundamental processes involved in methane fermentation is necessary for planning, building and operating biogas plants. [[Anaerobic_methods_waste_treatment|Anaerobic fermentation]] involves the activities of three different bacterial communities. The process of biogas-production depends on [[Parameters_and_Process_Optimisation_for_Biogas|various parameters]]. For example, changes in ambient temperature can have a negative effect on bacterial activity.
+Knowledge of the fundamental processes involved in methane fermentation is necessary for planning, building and operating biogas plants. [[Anaerobic methods waste treatment|Anaerobic fermentation]] involves the activities of three different bacterial communities. The process of biogas-production depends on [[Parameters and Process Optimisation for Biogas|various parameters]]. For example, changes in ambient temperature can have a negative effect on bacterial activity.
 Biogas microbes consist of a large group of complex and differently acting microbe species, notable the methane-producing bacteria. The whole biogas-process can be devided into three steps: hydrolysis, acidification, and methane formation. Three types of bacteria are involved.
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 |-
 | style="width: 45%" | <br/>
-| [[File:Fermscheme s.gif|border|550px|Fermscheme s.gif]]<small class="IMGLEGEND">'''The three-stage anaerobic fermentation of biomass'''</small><ref name="Production and Utilization of Biogas in Rural Areas of Industrialized and Developing Countries, Schriftenreihe der gtz, No. 97, p. 54; after: Märkl, H.: Mikrobielle Methangewinnung; in: Fortschritte der Verfahrenstechnik, Vol. 18, p. 509, Düsseldorf, FRG">Production and Utilization of Biogas in Rural Areas of Industrialized and Developing Countries, Schriftenreihe der gtz, No. 97, p. 54; after: Märkl, H.: Mikrobielle Methangewinnung; in: Fortschritte der Verfahrenstechnik, Vol. 18, p. 509, Düsseldorf, FRG</ref>
+| [[File:Fermscheme s.gif|border|right|550pxpx|The three stages of anaerobic fermentation of biomass|alt=Fermscheme s.gif]]<small class="IMGLEGEND">'''The three-stage anaerobic fermentation of biomass'''</small><ref name="Production and Utilization of Biogas in Rural Areas of Industrialized and Developing Countries, Schriftenreihe der gtz, No. 97, p. 54; after: Märkl, H.: Mikrobielle Methangewinnung; in: Fortschritte der Verfahrenstechnik, Vol. 18, p. 509, Düsseldorf, FRG">Production and Utilization of Biogas in Rural Areas of Industrialized and Developing Countries, Schriftenreihe der gtz, No. 97, p. 54; after: Märkl, H.: Mikrobielle Methangewinnung; in: Fortschritte der Verfahrenstechnik, Vol. 18, p. 509, Düsseldorf, FRG</ref>
 | style="width: 45%" | <br/>
 |}
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 In the first step (hydrolisis), the organic matter is enzymolyzed externally by extracellular enzymes (cellulase, amylase, protease and lipase) of microorganisms. Bacteria decompose the long chains of the complex carbohydrates, proteins and lipids into shorter parts. For example, polysaccharides are converted into monosaccharides. Proteins are split into peptides and amino acids.
 == Acidification ==
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 Acid-producing bacteria, involved in the second step, convert the intermediates of fermenting bacteria into acetic acid (CH<sub>3</sub>COOH), hydrogen (H<sub>2</sub>) and carbon dioxide (CO<sub>2</sub>). These bacteria are facultatively anaerobic and can grow under acid conditions. To produce acetic acid, they need oxygen and carbon. For this, they use the oxygen solved in the solution or bounded-oxygen. Hereby, the acid-producing bacteria create an anaerobic condition which is essential for the methane producing microorganisms. Moreover, they reduce the compounds with a low molecular weight into alcohols, organic acids, amino acids, carbon dioxide, hydrogen sulphide and traces of methane. From a chemical standpoint, this process is partially endergonic (i.e. only possible with energy input), since bacteria alone are not capable of sustaining that type of reaction.
 == Methanogenesis ==
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 {| cellpadding="10" border="0" align="right" style="width: 297px" class="IMGright"
 |-
-| [[File:Bacteria.gif|border|297px|Bacteria.gif]]<small class="IMGLEGEND">'''Various types of methanogenic bacteria. The spherically shaped bacteria are of the ''methanosarcina'' genus; the long, tubular ones are ''methanothrix'' bacteria, and the short, curved rods are bacteria that catabolize furfural and sulfates. The total length of the broken bar at top left, which serves as a size reference, corresponds to 1 micron.'''</small><ref name="Production and Utilization of Biogas in Rural Areas of Industrialized and Developing Countries, Schriftenreihe der gtz, No. 97, p. 55">Production and Utilization of Biogas in Rural Areas of Industrialized and Developing Countries, Schriftenreihe der gtz, No. 97, p. 55</ref><br/>
+| [[File:Bacteria.gif|border|297px|Bacteria.gif|alt=Bacteria.gif]]<small class="IMGLEGEND">'''Various types of methanogenic bacteria. The spherically shaped bacteria are of the ''methanosarcina'' genus; the long, tubular ones are ''methanothrix'' bacteria, and the short, curved rods are bacteria that catabolize furfural and sulfates. The total length of the broken bar at top left, which serves as a size reference, corresponds to 1 micron.'''</small><ref name="Production and Utilization of Biogas in Rural Areas of Industrialized and Developing Countries, Schriftenreihe der gtz, No. 97, p. 55">Production and Utilization of Biogas in Rural Areas of Industrialized and Developing Countries, Schriftenreihe der gtz, No. 97, p. 55</ref><br/>
 |}
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 <br/>
 = Composition and Properties of Biogas<br/> =

← Older revision		Revision as of 07:03, 28 April 2015
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