Biogas

Production

The biogas is a renewable energy that can be used for heating, electricity, and many other operations that use a reciprocating internal combustion engine, such as GE Jenbacher or Caterpillar gas engines. ^[4] To provide these internal combustion engines with biogas, the European Union ATEX centrifugal fan units built in accordance with the European Directive 2014/34 / EU (previously 94/9 / EG) are obligatory. These centrifugal fan units, for example Combimac , Meidinger AG and Witt & Sohn AG are suitable for use in Zone 1 and 2 .

Other internal combustion engines such as gas turbines are suitable for the conversion of biogas into both electricity and heat. The digestate is the remaining inorganic matter that has not been transformed into biogas. It can be used as an agricultural fertilizer.

Biogas is produced as

• as landfill gas (LFG), qui est produced by the breakdown of biodegradable waste inside a landfill due to chemical reactions and microbes, gold
• as digested gas, produced inside an anaerobic digester .

Projects such as NANOCLEAN are nowadays developing new ways to produce biogas more efficiently, using iron oxide nanoparticles in the processes of organic waste treatment. This process can triple the production of biogas ^[5] .

Biogas plants

A biogas plant is the name given to an anaerobic digester that treats farm wastes or energy crops. It can be produced using anaerobic digesters (air-tight tanks with different configurations). These plants can be fed with energy crops Such As maize silage or biodegradable wastes Including sewage sludge and food waste. During the process, the microorganisms transform biomass into biogas (mainly methane and carbon dioxide) and digestate .

Key processes

There are two key processes: mesophilic and thermophilic digestion which is dependent on temperature. In experimental work at the University of Alaska Fairbanks , a 1000-liter digester using psychrophiles harvested from “mud from a frozen lake in Alaska” has produced 200-300 liters of methane per day, about 20% -30% of the output from digesters. warmer climates. ^[6]

Dangers

The air pollution produced by biogas is similar to that of natural gas , but with an additional risk of hydrogen sulphide fraction and any unburned methane that escapes is a potent and long lived greenhouse gas.

Biogas can be explosive when mixed in the ratio of one part biogas to 8-20 parts air. Special recipes for biogas digester for maintenance work. It is important that a biogas system never has an explosion. Negative gas pressure can occur if too much gas is removed or leaked; Because of this biogas, it should not be used at pressures,

Frequent smell checks must be performed on a biogas system. If biogas is smelted anywhere, windows and doors should be opened immediately. If there is a fire the gas should be shut off at the gate valve of the biogas system. ^[7]

Landfill gas

Landfill gas is produced by wet organic waste decomposition under anaerobic conditions in a biogas. ^[8] [9]

The waste is covered and mechanically compressed by the weight of the material that is deposited above. This material prevents oxygen exposure thus allowing anaerobic microbes to thrive. Biogas builds up and is slowly moving into the atmosphere if the site has not been engineered to capture the gas. Landfill gas released in an uncontrolled way can be dangerous since it can become explosive when it escapes from the landfill and mixes with oxygen. The lower explosive limit is 5% methane and the upper is 15% methane. ^[10]

The methane in biogas is 20 times more potent to greenhouse gas than carbon dioxide. Therefore, uncontained landfill gas, which escapes into the atmosphere can greatly contribute to the effects of global warming . In addition, volatile organic compounds (VOCs) in landfill gas contribute to the formation of photochemical smog .

Technical

Biochemical oxygen demand (BOD) is a measure of the amount of oxygen required by aerobic micro-organisms to decompose the organic matter in a sample of material being used in the biodigester. daily energy output from a biodigester.

Another term related to biodigesters is effluent dirtiness, which tells us how much organic matter there is per unit of biogas source. Typical units for this measure are in mg BOD / liter. As an example, effluent dirtiness can range between 800-1200 mg BOD / liter in Panama. ^{[ quote needed ]}

From 1 kg of decommissioned bio-waste kitchen, 0.45 m³ of biogas can be obtained. The price for collecting biological waste from sales is approximately € 70 per ton. ^[11]

Composition

Typical composition of biogas

Compound	Formula	%
Methane	CH 4	50-75
Carbon dioxide	CO 2	25-50
Nitrogen	N 2	0-10
Hydrogen	H 2	0-1
Sulfide hydrogen	H 2 S	0.1 -0.5
Oxygen	O 2	0-0.5
Source: www.kolumbus.fi, 2007 [12]

The composition of biogas varies depending on the substrate composition, and the conditions within the anaerobic reactor (temperature, pH, and substrate concentration). ^[13]Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55% -75% methane, ^[14] which can be increased to 80% -90% methane using in-situ gas purification techniques. ^[15] As produced, biogas contains water vapor. The fractional volume of water vapor is a function of biogas temperature; correction of measured gas volume for water vapor and thermal expansion is easily done via simple mathematics ^[16] which yields the standardized volume of dry biogas.

In some cases, biogas contains siloxanes . They are formed from the anaerobic decomposition of materials commonly found in soaps and detergents. During combustion of biogas containing siloxanes, silicon is released and combined with free oxygen or other elements in the combustion gas . Deposits are formed containing mostly silica ( SiO
2 ) or silicates ( Si
x O
y ) and can contain calcium , sulfur , zinc , phosphorus . Such white mineral deposits accumulate to a surface thickness of several millimeters and must be removed by chemical or mechanical means.

Practical and cost-effective technologies to remove siloxanes and other biogas contaminants are available. ^[17]

For 1000 kg (wet weight) of input to a typical biodigester, total solids can be 30% of the weight while solids can be 90% of the total solids. Protein would be 20% of the volatile solids, carbohydrates would be 70% of the volatile solids, and finally fats would be 10% of the volatile solids.

Benefits of manure derived biogas

High levels of methane are produced when manure is stored under anaerobic conditions. During storage and when manure has been applied to the land, nitrous oxide is also produced as a byproduct of the denitrification process. Nitrous oxide ( N2O ) is more aggressive than carbon dioxide ^[18] and methane 25 times more than carbon dioxide. ^[19]

By converting cow manure into methane biogas via anaerobic digestion , the millions of cattle in the United States would be able to produce 100 billion kilowatt hours of electricity, enough to power millions of homes across the United States. In fact, one cow can produce enough manure in one day to generate 3 kiloWatt hours of electricity; only 2.4 kiloWatt hours of electricity are needed to power a single 100-Watt light bulb for one day. ^{[20] In} addition, it can be reduced by 99 million metric gold tones by 4%. ^[21]

Applications

Biogas can be used for electricity production on sewage works, ^[22] in a CHP gas engine , where the waste heat is conveniently used for heating the digester; cooking; space heating; water heating ; and process heating. If compressed, it can replace natural gas for use in vehicles, where it can fuel an internal combustion engine or fuel cells and is a much more effective exchanger of carbon dioxide than the normal use in on-site CHP plants. ^[22]

Biogas upgrading

Raw biogas produced from digestion is roughly 60% methane and 29% CO
2 with trace elements of H
2 S : inadequate for use in machinery. The corrosive nature of H
2 S alone is enough to destroy the mechanisms. ^[23] [24]

Methane in biogas can be concentrated via a biogas upgrader to the same standards as fossil natural gas , which becomes itself through a cleaning process, and becomes biomethane. If the local gas network permits, the producer of the biogas may use their distribution networks. Gas must be very clean to reach the pipeline of the correct composition for the distribution network to accept. Carbon dioxide , water , hydrogen sulphide , and particulates must be removed if present. ^[23]

There are four main methods of upgrading: water washing, swing pressure absorption, selexol absorption, and amine gas treatment . ^[25] In addition to these, the use of membrane separation technology for biogas upgrading is increasing, and there are several plants operating in Europe and USA. ^[23] [26]

The most prevalent method is water pollution where the flow of carbon dioxide and other trace elements are controlled by water. This arrangement could deliver 98% methane with manufacturers guaranteeing maximum 2% methane loss in the system. It takes roughly between 3% and 6% of the total energy output in a biogas upgrading system.

Biogas gas-grid injection

Gas-grid injection is the injection of biogas into the methane grid ( natural gas grid ). Until the breakthrough of micro combined heat and power two-thirds of all the energy produced by biogas power plants was lost (as heat). Using the grid to transport customers, the energy can be used for on-site generation ^[27] , resulting in a reduction of losses in the transportation of energy. Typical energy losses in natural gas transmission systems range from 1% to 2%; in electricity tranmission they range from 5% to 8%. ^[28] .

Before being injected into the gas grid, it is upgraded to natural gas quality. During the cleaning process, the users are removed. ^[29]

Biogas in transport

If concentrated and compressed, it can be used in your transportation. Compressed biogas is widely used in Sweden , Switzerland , and Germany. A biogas-powered train, named Amanda Biogaståget (The Biogas Train Amanda), has been in service in Sweden since 2005. ^[30] [31] Biogas automotive powers. In 1974, a British documentary film titled Sweet as a Nutdetailed the biogas production process from pig manure and showed how it is fueled by a custom-adapted combustion engine. ^[32] [33] In 2007, an estimated 12,000 vehicles were being fueled with upgraded biogas worldwide, mostly in Europe. ^[34]

Measuring in biogas environments

Biogas is part of the gas and condensing gas (or air) category that includes gas or fog in the gas stream. The mist or fog is predominately water vapor that condenses on the sides of pipes or stacks throughout the gas flow. Biogas environments include wastewater digesters, landfills, and animal feeding operations (covered livestock lagoons).

Ultrasonic flow meters are one of the few devices capable of measuring in a biogas atmosphere. Most of the thermal flow meters can not be supplied because of the moisture flow and the flow of water. They can handle moisture variations that occur in the flow of daily and seasonal fluctuations, and account for the moisture in the flow to produce a dry gas value.

Legislation

European Union

The European Union has legislation regarding waste management and landfill sites called the Landfill Directive .

Countries such as the United Kingdom and Germany now have legislation in force that provides farmers with long-term revenue and energy security. ^[35]

United States

The United States legislates against landfill gas as it contains VOCs . The United States Clean Air Act and Title 40 of the Code of Federal Regulations (CFR) requires landfill owners to estimate the quantity of non-methane organic compounds (NMOCs) emitted. If the estimated NMOC emissions exceed 50 tons per year, the landfill is required to collect the NMOCs. Treatment of the landfill is usually by combustion. Because of the remoteness of landfill sites, it is sometimes not economically feasible to produce electricity from the gas.

Global developments

United States

With the many benefits of biogas, it is starting to become a popular source of energy and is used in the United States more. In 2003, the United States consumed 147 trillion BTU of energy from “landfill gas”, about 0.6% of the total US natural gas consumption. ^[34] Methane biogas derived from cow manure is being white tested in the US According To a 2008 study, the file Managed by the Science and Children magazine, methane biogas from cow manure Would Be Sufficient to Produce 100 billion kilowatt hours enough to power millions of homes across America. Furthermore, methane biogas has been tested to prove that it can reduce 99 million metric tons of greenhouse gas emissions or about 4% of the greenhouse gases produced by the United States. ^[36]

In Vermont, for example, biogas generated on dairy farms was included in the CVPS Cow Power program. The program was originally offered by Central Vermont Public Service Corporation as a volunteer and a recent merger with Green Mountain Power is now the GMP Cow Power Program. Customers can elect to pay a premium on their electric bill, and that premium is passed directly to the farms in the program. In Sheldon, VermontGreen Mountain Dairy has provided renewable energy as part of the Cow Power program. It starts when the brothers who own the farm, Bill and Brian Rowell, and they want to address some of the manure management challenges faced by dairy farms, including manure odor, and nutrient availability for the crops they need to grow to feed the animals. They installed an anaerobic digester to process the cow and milking center of their 950 cows to produce renewable energy, a bedding to replace sawdust, and a plant-friendly fertilizer. The energy and environmental attributes are sold to the GMP Cow Power program. On average, the system run by the Rowells produces enough electricity to power 300 to 350 other homes. The generator capacity is about 300 kilowatts. ^[37]

In Hereford, Texas , cow manure is being used to power an ethanol power plant. By switching to methane biogas, the power plant has 1000 barrels of oil a day. Over all, the power plant will depend on the future of biogas. ^[38]

In Oakley, Kansas , an ethanol plant is one of the largest biogas facilities in North America using Integrated Manure Utilization System “IMUS” to produce heat for its boilers by utilizing feedlot manure, municipal organics and ethanol plant waste. At full capacity the plant is expected to replace 90% of the fossil fuel used in the manufacturing process of ethanol. ^[39] [40]

Europe

The level of development varies greatly in Europe. While countries such as Germany, Austria and Sweden are fairly advanced in their use of biogas, there is a vast potential for this renewable energy source in the continent, especially in Eastern Europe. Different legal frameworks, education schemes and the availability of technology are among the prime reasons behind this untapped potential. ^[41] Another challenge for the further progression of biogas has been negative public perception. ^[42]

In February 2009, the European Biogas Association (EBA) was founded in Brussels as a non-profit organization to promote the deployment of sustainable biogas production and use in Europe. EBA’s strategy defines three priorities: establish biogas as an important part of Europe’s energy mix, promote source separation of household waste to increase potential, and support the production of biomethane as fuel. In July 2013, it had 60 members from 24 countries across Europe. ^[43]

UK

As of September 2013 , there are about 130 non-seeding biogas plants in the UK. Most are on-farm, and some larger facilities exist off-farm, which are taking food and consuming wastes. ^[44]

On October 5, 2010, biogas was injected into the UK gas grid for the first time. Sewage from over 30,000 Oxfordshire homes is to feel Didcot sewage treatment works, Where It is Treated in anaerobic digestor year to Produce Biogas, qui est Then cleaned to Provide for gas Approximately 200 homes. ^[45]

In 2015 the Green-Energy company Ecotricity announced their plans to build three grid-injecting digesters.

Germany

Germany is Europe’s biggest biogas producer ^[46] and the market leader in biogas technology. ^[47] In 2010 there were 5,905 biogas plants operating throughout the country: Lower Saxony, Bavaria, and the eastern federal states are the main regions. ^[48] Most of these plants are employed as power plants. Usually the biogas plants are directly connected to a CHP which produces electric power by burning the bio methane. The electrical power is then fed into the power grid public. ^[49] In 2010, the total installed electrical capacity of these power plants was 2,291 MW. ^[48] The electricity supply was 12.8 TWh, which is 12.6% of the total generated renewable electricity. ^[50]

Biogas in Germany is extracted from the co-fermentation of energy crops (called ‘NawaRo’, an abbreviation of nachwachsende Rohstoffe , German for renewable resources) mixed with manure. The used crop is corn. These chemicals are also used for biogas generation. ^[51] In this respect, biogas production in Germany differs significantly from the UK, where biogas generated from landfill sites is most common. ^[46]

Biogas production in Germany has been developed over the last 20 years. The main reason is the legally created frameworks. Government support of renewable energy started in 1991 with the Electricity Feed-in Act ( StrEG ). This law guarantees the producers of energy sources, which means that they are forced to produce energy from independent private producers of green energy. ^[52] In 2000 the Electricity Feed-in Act was replaced by the Renewable Energy Sources Act ( EEG ). This law even guaranteed a fixed compensation for the produced electric power over 20 years. The amount of around 8 ¢ / kWh gives farmers the opportunity to become energy suppliers and a further source of income. ^[51]

The German agricultural biogas production was given a further push in 2004 by implementing the so-called NawaRo-Bonus. This is a special payment for renewable resources, that is, energy crops. ^[53] In 2007, the German government stressed its intention to invest further and strengthen the energy supply and provide an answer to growing climate challenges and increasing oil prices through the Integrated Climate and Energy Program.

This continual trend of renewable energy has a number of challenges in the management of renewable energy and has several impacts on biogas production. ^[54] The first challenge to be noticed is the high-consuming area of ​​the biogas electric power supply. In 2011 energy crops for biogas production in the area of ​​800,000 ha in Germany. ^[55]This high demand of agricultural areas has new competitions with food industries that do not exist hitherto. Moreover, new industries and markets have been created in the form of predominantly rural regions with an economic, political and civil background. Their influence and acting is to be of benefit to all. Finally biogas will further play an important role in the German renewable energy supply if good governance is focused. ^[54]

Indian Subcontinent

Biogas in India ^[56] has been traditionally based on a long period of time, especially in rural India. In the last 2-3 decades, research organizations with a focus on rural energy security have enhanced the design of the resulting systems resulting in low cost designs such as the Deenabandhu model.

The Deenabandhu Model is a new biogas-production model popular in India. ( Deenabandhu means “friend of the helpless.”) The unit usually has a capacity of 2 to 3 cubic meters. It is constructed using bricks or by a ferrocementmixture. In India, the brick model is slightly more than the ferrocement model; However, India’s Ministry of New and Renewable Energy offers some subsidies for model construction.

LPG (Liquefied Petroleum Gas) is a key source of cooking fuel in urban India and its prices have been increasing along with the global fuel prices. Also available in: English (1) French (1) French (1) French (1) LPG as a domestic cooking fuel has become a financial burden renewing the focus on biogas cooking alternative fuel in urban establishments. RCC and Cement Structures for the Future of Structural Feasibility Renewed focus on process technology like Biourja process model ^[57] has an alternative to LPG as primary cooking fuel.

In India, Nepal, Pakistan and Bangladesh biogas produced from the anaerobic digestion of manure in small-scale digestion facilities is called gobar gas ; It is estimated that such facilities exist in over two million households in India, 50,000 in Pakistan, and particularly North Punjab, due to the thriving population of livestock. The digester is an airtight circular pit made of concrete with a pipe connection. The manure is directed to the pit, usually straight from the cattle shed. The pit is filled with a quantity of wastewater. The gas pipe is connected to the kitchen fireplace through control valves. The burning of this biogas has very little smell or smoke. Owing to simplicity in the implementation of rural areas, it is one of the most environmentally sound energy sources for rural needs. One type of these system is the Sintex Digester. Some designs use vermiculture to further enhance the slurry produced by the biogas plant for use as compost. ^[58]

To create awareness and associate interest in biogas, the Indian Biogas Association ^[59] was formed. It aspires to be a unique blend of nationwide operators, manufacturers and planners of biogas plants, and representatives of science and research. The association was founded in 2010 and is now ready to start mushrooming. Its motto is “propagating Biogas in a sustainable way”. They have launched a Biogas App ^[60] to calculate the substrates and biogas plants and substrate availability. The next version of the app.

In Pakistan, the Rural Support Programs Network is running the Pakistan Domestic Biogas Program ^[61] which has installed 5,360 biogas plants ^[62] and has trained in over 200 bios on the technology and aims to develop the Biogas Sector in Pakistan.

In Nepal, the government provides subsidies to build biogas plant at home.

China

The Chinese have experimented with the applications of biogas since 1958. Around 1970, China had installed 6,000,000 digesters in an effort to make agriculture more efficient. During the last years the technology has high growth rates. This is a new development in biogas from agricultural waste. ^[63]

In developing nations

Domestic biogas plants and livestock manure and night soil in biogas and slurry, the fermented manure. This technology is possible for small-holders with livestock production 50 kg manure per day, an equivalent of about 6 pigs or 3 cows. This manure has to be collected by the plant. Toilets can be connected. Another precondition is the temperature that affects the fermentation process. With an optimum at 36 C ° the technology especially applies for those living in a (sub) tropical climate. This makes the technology for small holders in developing countries often suitable. ^[64]

Depending on size and location, a typical brick made plant can be installed at the yard of a rural household with the investment between US $ 300 to $ 500 in Asian countries and up to $ 1400 in the African context. ^[65] High quality biogas plant requirements and minimum maintenance and costs for at least 15-20 years without major problems and re-investments. For the user, biogas provides clean cooking energy, reduces indoor air pollution, and reduces the time needed for traditional biomass collection, especially for women and children. The slurry is a clean organic fertilizer. ^[64]

Domestic biogas technology is a proven and established technology in many parts of the world, especially Asia. ^[66] Several countries in this region have embarked on large-scale programs on domestic biogas, such as China ^[67] and India.

The Netherlands Development Organization , SNV, ^[68] supports national programs on domestic biogas that aim to establish commercial-viable domestic biogas sectors in which local companies market, install and service biogas plants for households. In Asia, SNV is working in Nepal, ^[69] Vietnam, ^[70] Bangladesh, ^[71] Bhutan, Cambodia, ^[71] Lao PDR, ^[72] Pakistan ^[73] and Indonesia, ^[74] and in Africa; Rwanda, ^[75] Senegal, Burkina Faso, Ethiopia, ^[76] Tanzania, ^[77] Uganda, Kenya, ^[78] Benin and Cameroon.

In South Africa a Biogas system is manufactured and sold. One key feature is that installation requires less skill and is quicker to install the digester tank is premade plastic. ^[79]

Society and culture

In the 1985 Australian film Mad Max Beyond Thunderdome the post-apocalyptic settlement Barter town is powered by a central biogas system based upon a piggery. As well as providing electricity, methane is used to power Barter’s vehicles.

“Cow Town”, written in the early 1940s, discusses the work of a metropolitan biogas. Carter McCormick, an engineer from a town outside the city, is in a position to use this power, rather than suffocate, the city.

The Biogas production is providing new opportunities for skilled employment, drawing on the development of new technologies ^[80] .

References