Biogas – The source of future energy (0)

Tartu Miina Härma gymnasium
Biogas – The source of future energy
Report
Tartu 2010

Table of Contents

Introduction 3
What is biogas? 4
Producing process 5
Nowadays 6
Areas where biogas is used in 7
Biogas as replacement of fuel 7
Other benefits 8
Health 8
Economical 9
Dangers of biogas 9
Future prospects 10
Conclusion 12
Used sources 13

Introduction

To be honest I got the list of topics after most interesting ones for me were taken. At first I was not very satisfied with my topic but then I realized that this could be actually really interesting thing to make a report of. I chose this particular topic because I have always been interested in green energy. This topic gave me an excellent opportunity to improve my knowledge about these kinds of things. For me this report is a great challenge because I have not done anything like this before , especially in English . Primary goal for me is to improve my knowledge about renewable energy and also usage of English language.
This report is going to talk about biogas. It provides a brief review of usage and future prospects of the biogas. I have tried to make this report as understandable as possible. By the end of this report I want to come to a conclusion whether biogas is the best source of future energy or are there any other sources that are better.

What is biogas?

Typically it refers to the gas produced by the anaerobic digestion or fermentation of organic matter including manure, sewage sludge, municipal solid waste , biodegradable waste. If opportunely refined it can be used for electricity production . Also for space -, water- or process heating.
Unintentional production of biogases has been an ongoing issue in many regions of the world, and several nations have also looked to biogas as a potential source of  clean energy. India and China have both invested extensively in creative biogas  technology to provide fuel for their citizens and there are a number of interesting applications for this gas which appeal to people who are interested in sustainable energy and the health of the environment.
The basis for biogas is organic material such as food scraps and feces which are held in an anaerobic area, which can range from a  storage tank which is not ventilated to a device which is specifically designed to produce gases. The conditions attract anaerobic bacteria , which start to break down the organic material, producing methane and  carbon  dioxide as a by-product. Another type of biogas which includes  hydrogen , nitrogen, and carbon monoxide can be obtained through the gasification of biomass such as wood or rice husks, a technique which is used to manufacture gas industrially.
The gases produced through anaerobic fermentation or gasification are combustible in addition to having a strong smell which makes them stand out to the human nose. Methane leaks from landfills are an ongoing problem, as is the production of biogas in poorly maintained compost piles, manure lagoons, and outhouses. Spontaneous fires and explosions caused by build -ups of gas have been recorded in many regions of the world, illustrating a major problem which needs to be confronted by waste management companies . When this gas is trapped, however , it can be made useful, instead of just being a nuisance.
Trapped biogas can be used to power stoves for cooking and heating, in addition to other applications. By trapping the gases, people can prevent methane from reaching the atmosphere, thereby reducing degradation caused by methane gas. The ability to turn waste products into something which can be utilized is also rather convenient, especially in developing countries, where available resources may be limited. Furthermore, by turning biomass into biogas, people can address issues like sewage treatment, ensuring that raw sewage is not released into the natural environment.

Producing process

Biogas is normally produced by using the excreta of animals as the source material.
In most of the countries where biogas is produced, the excreta of the cattle and other farm animals are used. In India gobar or cow dung is used for the purpose of making biogas. 20% of the excreta of animals are made up of dust particles that are inorganic in nature. The percentage of the inorganic dust particles is brought down by combining water with the excreta in a 1:1 ratio. The rate of feeding of any biogas manufacturing plant that is based on dung is 3,500 kilograms per day. 
Under normal circumstances the microbial content of the biogas is maintained by the addition of 2% of the expended slurry of the slurry of the fresh dung. 1% calcium ammonium nitrate of the dung is combined with the slurry in such cases . At times waste of kitchens and excrement of human bodies is used in these processes. The human excreta are supposed to occupy, at the most, 3% of the slurry. 
The addition of human excreta is crucial in this context as it increases the amount of production of biogas. This is because human excreta have high nitrogen content. The ideal temperature for producing biogas is within 35 to 38 degrees Celsius . If the temperature is lower than that then the production of biogas may go down as well. If the temperature is 15 degree Celsius then it would be impossible to produce any biogas.  This is precisely the reason as to why thermal insulation is necessary to produce biogas when it is the winter season or at places where the temperatures are normally lower than the requisite level. The heating of digesters is also pretty important in this regard. The pH of the slurry has to be close to 7. This is pretty much possible provided that cow dung is employed in the form of a substrate.
If favourable conditions may be provided then as much as sixty liters of biogas may be produce for one kilogram of cow dung. 
The digesters that are used for the purpose of production of biogas can be used in mesophilic conditions, which mean a temperature range of 20 to 25 degrees Celsius to 40 to 45 degrees Celsius. The digesters can also be run in thermophilic conditions, where the temperature range is from 50 to 55 degrees Celsius to 60 to 65 degrees Celsius. 
Both these conditions call for separate species of bacteria. It is thought that the mesophilic operations are more safe and stable than the thermophilic operations that are capable of inactivating the parasites of animals and the various pathogens.

Nowadays

Waste management business Sterecycle owns patented technologies that are capable of recycling and recovering up to 80 per cent of waste typically produced by a household. Rarbach cited oil major Shell’s tie up with Cosan as being one of the most notable strategic partnerships that has taken place last year . The $12bn joint venture will see the pair produce and sell sugar, energy and ethanol from sugarcane, and distribute fuels for transportation and industry from the companies’ integrated distribution and retail networks in Brazil . Through the deal, Shell strengthened its whole business in biofuel and bioethanol. Sterecycle was debating whether to list in Canada or in its domestic market on the AIM exchange in London.
French chemical company Rhodia's subsidiary Rhodia Energy Services has launched two biogas projects in China and Vietnam , it said on Thursday. Rhodia Energy Services will manage the design and construction of the two facilities , as well as the operations and sales of the biogas produced, it said in a statement. Rhodia has partnered with the Siyuan ethanol factory in southern China to treat waste water. The facility started up in March and will produce 150,000 cubic metres of biogas a day by January next year and reduce carbon dioxide emissions by 100,000 tonnes a year. The second project is based at the Nuoc Trong cassava starch factory in Vietnam, which has recently started operations. It will produce 150,000 cubic metres of biogas a day and reduce emissions by 12,000 tonnes per year. Rhodia said are working on plans to develop biogas in Thailand and Malaysia and had begun three projects in China and Vietnam.

Areas where biogas is used in

Usage in Heating: acquired biogas is burned by a burner and the gained heat is used in houses, animal stables, greenhouses and inside the facility. Biogas stoves, hot water cauldrons or steam cauldrons are generally used in this system. The biogas purification before usage is important to eliminate corroding hydrogen sulphur (H2S) and carbon dioxide.
Usage in Cooking: Biogas can be used in kitchens, as fuel for ovens and stoves using LPG (Liquefied Petroleum Gas).
Usage in Lighting: Biogas can be used in LPG-using lamps by burning directly and also by transforming into electricity. The efficiency level is low like 3% when burning.
Preparing Hot Water: We can use biogas to provide hot water at home and industrial need and also for geyser and other water heater systems.
Usage in Internal Combustion Engine: Biogas can be used in vehicles as an alternative fuel to common energy sources. Especially in Europe , this kind of applications is encouraged by several projects. 
Electricity Production: Especially in medium and large facilities, biogas is used in electric generators. The electric transformation efficiency of biogas is about 22%- 40%.

Biogas as replacement of fuel

Biogas is used as transportation fuel in a number of countries, but in Europe it has only reached a major breakthrough in Sweden . All of the biogas plants in Sweden that are in the planning or construction phase will be equipped with possibilities to deliver a biogas that is upgraded to natural gas quality , either for direct use as vehicle fuel or for injection into the natural gas grid .
Biogas can be used in both heavy duty and light duty vehicles. Light duty vehicles can normally run both on natural gas and biogas without any modifications, whereas heavy duty vehicles without closed loop control may have to be adjusted, if they run alternately on biogas and natural gas. Sweden is the only country in the world with a national standard for biogas as vehicle fuel today. This standard essentially states that the methane content must be higher than 95% and also sets limits for dew point, sulphur content and some other minor constituents.
Upgrading of biogas is a relatively new technology but experience from Sweden and other countries shows that it is possible now to upgrade biogas with high reliability
and at reasonable costs . The Swedish experience shows that biogas can be an
economical sustainable fuel with a potential to drastically reduce emissions in urban transport.

Other benefits

Wastes do not perish. Instead of that, they become more valuable compost. The weeds in animal compost cannot germinate. Biogas has especially positive health effects in rural areas. Smell of animal compost disappears widely after biogas production. Also, disease agents threatening human health coming from animal waste become inactive.

Health

Biogas can have significant health benefits. According to the Integrated Environmental Impact Analysis carried out by BSP for 600 biogas users and 600 non-users, four percent more non-biogas users have respiratory diseases than those who own biogas plants. Qualitative information from various household surveys carried out by BSP has revealed that problems like respiratory illness, eye infection, asthma and lung problems have decreased after installing a biogas plant 
According to the Biogas Users’ Survey conducted in 2000 with 100 households, biogas can have positive impacts on the health of its users. Out of 42 respondents who had respiratory problems in the past, it was reported that the problem has improved for 34 of them. Similarly, those who had problems like asthma, eye infections and lung problems found that their problems had decreased after displacing dirtier fuels with biogas.
If parasitic diseases had previously been common, the improvement in hygiene also has economic benefits (reduced working time). The more fully the sludge is digested, the more pathogens are killed . High temperatures and long retention times are more hygienic.
The availability of biogas can have effects on nutritional patterns too. With easy access to energy, the number of warm meals may increase . Whole grain and beans may be cooked longer, increasing their digestibility, especially for children . Water may be boiled more regularly, thus reducing waterborne diseases.
Biogas plants also improve health conditions in the homes :
Since biogas burns clean, homes do not fill with smoke and ash. Women and children experience less bronchial problems and can expect to live longer. Homes are also more hygienic. Dung cakes are no longer stored in the homes. Cooking with gas takes less time than with wood or charcoal or any other commonly used fuel. It is easier to cook with gas stove.

Economical

Estimating an average per capita consumption of 3 kg of wood per day for energy (cooking, heating and boiling water) in rural areas, the daily per capita demand of energy equals about 13 kWh which could be covered by about 2 m3 of biogas. A biogas plant therefore directly saves forest .
Annually, each biogas plant can save more than four ton's of firewood and 32 liters of kerosene.
 A single biogas system with a volume of 100 cubic feet (2,8 m3) can save as much as 0.3 acres (0,12 ha) of forest ( woodland ) each year.
 A recent study by Winrock, Nepal and others found that each biogas plant can mitigate about five tons of carbon dioxide equivalents per year.

Dangers of biogas

Anaerobic digestion systems and associated manure storage and handling present many safety hazards . A good designer and responsible digester owner will learn about and be concerned with safety from the very beginning of any digester project. A qualified digester designer, builder or equipment supplier should have excellent knowledge about and be sensitive to the safety needs of workers and visitors around a biogas system. Areas of concern will likely include :
Gas releases that are flammable , explosive or immediately toxic.
Hydrogen Sulfide gas, which can accumulate in the bottom of tanks and pump sumps, can kill almost instantaneously.
Carbon Monoxide gas can accumulate in engine and machine rooms from engine exhaust and poorly operating boilers.
Biogas can accumulate under roofs and ceilings in explosive mixtures.
Confined spaces that may be immediately hazardous to life and should only be entered using appropriate procedures and equipment. 
Noise levels that require workers to wear hearing protection .
Liquid tanks and ponds that may result in drowning.
Pumps and other machinery that are entanglement hazards due to rotating shafts, pinch points and other moving parts. 
Biogas and manure liquids that cause rapid corrosion or failure of electrical equipment, gas handling piping and building components.
Small children and unaware visitors who can wonder into areas of danger and become serious injured or drown.
Ladders, platforms and roofs without guards, cages or other fall prevention measures. 
Dirty liquids and gases escaping under high pressure .

Future prospects

There must be more researches about many topics concerning biogas in order to make biogas technology applicable and to achieve success from the investments in this field . Researches done up until now have provided a good amount of information, but this is not enough. The fields that will be worked on first are stated below:
Development of the way of implanting biogas plants according to the environmental conditions,  
Determining the cheap and regional isolation materials,  
Developing the biogas usage tools , 
Determining how biogas can be produced from herbal wastes, 
Researching the effects of the compost of biogas facilities on herbal production and soil characteristics,  
Developing the distribution and transportation mechanism of the compost from the biogas facilities,  
The calculation of contribution that biogas will have on environmental health  
The researching of social economical effects on biogas production technology on rural areas.
Especially in the last years, the increasing of fuel costs in Turkey has been affecting the poor section of the public economically. Because the poor section can not afford these fuels, they prefer to use wood so this causes to reduce the forestall areas which are already insufficient. This is why proper Works and investments should be done on new alternative energy sources.

Conclusion

Every day more and more carbon dioxide is added to atmosphere. Biogas can prevent the further increase of carbon dioxide in atmosphere. I feel that by using biogas we can stop the increase of global warming  but we can’t reduce already present carbon dioxide level in atmosphere. So the earth remains as polluted as it is but it prevents atmosphere from getting imbalanced more. But it is not a perfect solution. For example I think that hydrogen fuel is way better than biogas fuel, because hydrogen is the most abundant chemical element, constituting roughly 75 % of the Universe 's chemical elemental mass. So, I think that biogas is definitely a source of future energy but there are other alternatives which can be useful for us.
This report gave me lot of knowledge about biogas as well as other fields of renewable energy. Also I think that my English has improved thanks to the new vocabulary and material I have worked through. Despite of scientific text and complicated words I managed to understand the topic and make it as easy as possible for others to follow.

Used sources

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