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Biogas

Table of contents

Num Title Description
1 Biogas General document about Biogas

 

Biogas

1 Formation
2 Factors that effect biogas production
3 The Economy of biogas Production
4 Advantages of Biogas
5 Benefits of biogas production    
6 Biogas plant
7 Future and Funding
8 Planning
9 Areas where Biogas is used in
10 Cogeneration and Trigeneration Facilities:
11 Works in Europe and Around the World
12 Works About Biogas In Turkey   
13 An Example: Energy Production from Waste Gas:
14 Model example of a biogas plant in Darmstadt-Wixhausen:

1 Formation

First stage consists into making the waste dissolvable by the enzymes secreted from micro organisms.
Then, the acid forming bacteria takes action and transforms these substances into small-structured substances like acetic acid.
After that the methane forming bacteria converts these substances into biogas.
Hydrolysis stage: Long chained complex carbohydrates proteins oils and lipids are transmuted into short chained forms. The first step known as hydrolysis is completed after this transmutation into basic organics.
Acid formation stage: The dissolvable organic materials are transformed into small-structured materials as acetic acid volatile fatty acids hydrogen and carbon dioxide.
Methane formation: The stage of acetic acid disintegration or hydrogen and carbon dioxide synthesis to acquire biogas by bacteria.

2 Factors that effect biogas production

The effects of heat: Methanogenic bacteria are inactive at very high or very low temperatures. That’s why the reactor heat effects the biogas production or its speed directly.
The effects of PH: The most suitable PH levels for methane producing bacteria are neutral or have slightly alkali rates.
The effects of toxicity: Antibiotic addition to foods in chicken farming has a toxicity effect in chicken compost using systems in biogas production.
The effects of organic load speed: Organic load speed is daily organic material supply amount to bioreactors.

3 The Economy of biogas Production

The most important factors are the economical wastes’ worth and their biogas efficiency. The selected technology takes effects in production efficiency and costs as well as in investment costs. The discounts or limitations on these energy sources by local executives change the convenience of biogas economy. It must be calculated how these investments will pay back and how these values will effect the investment’ cost.

4 Advantages of Biogas

In our country animal and herbal wastes are burned directly or they are used as compost agricultural soil. But it is more common to burn wastes for heat production.
Biogas production provides storage or organic wastes under controllable-suitable conditions. The uncontrolled storage of farm originated organic wastes-composts pollutes water earthy and the air.

5 Benefits of biogas production

Biogas is a clean and high heat-capacited energy source.
Wastes do not perish. Instead of that, they become a 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.

6 Biogas plant

A biogas plant has four main components.

  • Preliminary storage pit of liquid manure and co-substrates
  • Fermenter: most important component where bacteria decompose organic substances into biogas.
  • Fermentation residue storage: fertiliser.
  • Combined heat and power plant: cleaning, removal of sulphides, electricity production and network supply.

7 Future and Funding

Biogas plants figure is steadily rising. In 2006 in Germany there were approximately 3.300 plants, with a total output of 950 MW. The gas is used to generate electricity and heat products, as well as heating gas. The forecast for 2007 is a total number of 3.900 installations which together generate an electrical output of 1300 MW.

The federal government promotes renewable energy use and measures to conserve energy through the credit institute for reconstruction (KfW) and the Federal Office of Economics and Export Control (BAFA). Apart from the federal states and municipalities, promoting appropriate technologies, they can

8 Planning

Biogas plants can be run as a single generator where a farmer uses the own organic substances or in large community plants supplied by many farmers. The electrical power of a single plant can be up to thirty kW. Multi plants can even generate several MW. At present, the average power of a new plant is approximately 330 kW and it depends on the amount of the biomass.        
The costs per kW of installed capacity is approximately between 2000 € / kW and 5000 € / kW. The costs depend on the type of engine, with a plant running 7000 hours a year. Up to 1 million kWh of electricity can be generated.
The financing of a biogas plant is made by the individual federal states.

9 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 systems. 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.
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: Espacially in medium and large facilities, biogas is used in electric generators. The electric transformation efficiency of biogas is about 22%- 40%.

10 Cogeneration and Trigeneration Facilities:

The usage of biogas in cogeneration facilities, where both heat and electricity can be produced, is becoming more and more common. In this processes, the energy transformation efficiency can be rise up to 85-88%. In addition to heat and electric production, biogas can be used in trigeneration applications, which can help the idle capacity to be used in hot seasons, when the load of volumetric heating is especially increased but the cooling need is increased, including an absorbing cooling unit in the system.

Also, the levels of corbondioxide and hydrogen sulphur of biogas can be decreased to acceptable levels. After this process, biogas can be used in natural gas systems directly. So we can use biogas in every field that includes natural gas.

11 Works in Europe and Around the World

The anaerobic reactor number in the European countries are increasing every year this is why it is hard to make a comparative analysis covering all European countries. It has been detected that in 1994, there were 397 industrial anaerobic purification facilities (Nyns, 1994). With this number, comparing analysis’s have been done, adding the number of anaerobic purification facilities in Turkey. The spread of anaerobic purification facilities by countries can be seen in Table-Z. The most number of anaerobic purification facilities is located in Germany, Holland, France and Italy, respectively. In 1994, there were 99 facilities in Germany, and in 1999, this number was increased to 125 (Austermann-Haun vd., 1999).  The facility numbers in unit area and unit population is given in Table-2. North European small countries such as Holland, Denmark and Belgium use this technology a lot. Turkey is the last country by the anaerobic facility number for one million people in Europe. 

Table-2: The spread of industrial anaerobic purification facilities in Europe since 1994 (Nyns, 1994)

 

Quantity

quant./1000 km2

adet/106 kişi

Germany

99

0.25

1.40

Netherlands

83

2.40

5.60

France

55

0.11

1.00

Italy

50

0.15

0.80

Belgium

25

0.80

2.60

England

25

0.11

0.50

Spain

23

0.07

0.60

Denmark

18

0.45

3.90

Turkey

29

0.02

0.28

Portugal

7

0.09

0.40

Ireland

5

0.09

1.50

Greece

4

0.02

0.40

12 Works About Biogas In Turkey

The direct burning of compost for heating in Turkey causes the organic material which is very important for the soils disappear and wood usage destroys the forests which are already poor.  
Minimum precautions must be taken to protect forests and we need to eliminate the disease agents that are threatening human health and make a positive effect on rural areas’ environment.  
The Works on biogas in Turkey have been done for many years by The Ankara Research Institute Directorate of Rural Areas and after being stopped in 1986, no institutional activity was found, but interest of the stockbreeding companies to form a biogas plant is still increasing. Many companies both small and big are using biogas and now we can see private sector investments on this type of energy. 
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.

13 An Example: Energy Production from Waste Gas:

In this system, the gases that are formed in the collection field are collected by an active collection system and burned by being sent to gas motors and then electricity and heat are produced.

The waste gas that is formed in the collection areas is 20 times more effective than the greenhouse effect (the effect to heat up the atmosphere) of the carbon dioxide. By this, in this system, we overcome the problems of the uncontrolled gases without harming the environment and we decrease the risk of explosion.

The uncontrolled gases that are formed from 5.7 million m³ solid waste are used as fuels in the special gas motors that contain 20 cylinders. In motors, the gases are transformed into heat energy. Then they are transformed into electricity in generators.

The Kemerburgaz dump that was being used as a wild collection field in the beginning was rehabilitated after the year 1995 and with this, the project of “Electricity Production From Waste Gas (%35 Methane)” was started.

The facility that has the capacity of 4 MW of built power produces about 8 000 000 kWh of electricity energy and the energy that is produced is given to the interconnect system. The gases that come out from the collection area will, in time decrease and in 10 years, supply approximately 1 500 houses’ electricity need.

14 Model example of a biogas plant in Darmstadt-Wixhausen:

The biogas plant in Darmstadt – Wixhausen runs by HEAG Südhessische Energy and is supplied with biomass by several farmers. About 12,000 tonnes of organic substances will be converted to 2.5 million cubic meters of biogas within a year and finally be fed into the power system. This amount is sufficient to supply a number of 600 single-family – houses with energy.
A large silo is used for the storage of renewable materials. The plant in Wixhausen owns 3 fermenters and a co-generation plant that supplies the power grid of HSE (HEAG Südhessische Energy) with electricity.  The investment of 3.5 million Euro pays off, as it contributes to climate protection, and saves 3,500 tons of carbon dioxide annually.

Silo
Silo
Silo
Silo
Scale
Fermenter
Milter

The start of construction of the plant was in June 2007 and it is expected to be finished by March 2008, then the gas processing plant can be used.
Technical data of the biogas plant in Darmstadt - Wixhausen

Fermentation subtracts

11.500 t/a silage of maize

650 t/a Manure

400 t/a Cereals

Biogas production

2,5 million m3/a

Natural biogas gas

1,3 million m3/a

Gas utilization

4,5 million KWh electrical energy

5,5 million kWh thermal energy

CO2 savings

3.500 t/a