Biogas Production

Content

Project description……………………………………………………………………………..3


Introduction………………………………………………………………………………………..3


Process of biogas production………………………………………………………………4


Types of reactors………………………………………………………………………………..7


Factors affecting biogas production……………………………………………….....8


The use of biogas……………………………………………………………………………….10Conclusion………………………………………………………………………………………...11


References.............................................................................................12





















PROJECT DESCRIPTION

Nowadays, the preservation of the environment and the growing consumption of energy resources are two important issues, so it is necessary to apply new low cost technologies and waste purificators to obtain usable products. [1]
During biogas production it is possible toobtain several components like methane and other liquid and solid residues. The methane is often used as fuel while the residues could be landfilled or used in farmland( when the landfilled material is used, it is necessary to assess the possible presence of toxic component in the leachate ).[2]The aim of our study is to find how biogas is produced ,types of reactors, the factors involved and itsuse.

INTRODUCTION
Biogas is originated in a biological process in which under anaerobic conditions and the action of specific bacteria organic matter is decomposed. The natural generation of biogas is an important part of the biogeochemical carbon cycle. Methanogens (methane producing bacteria) are the last link in a chain of micro-organisms which degrade organic material and return thedecomposition products to the environment. In this process biogas is generated, a source of renewable energy. [3]

Biogas contains a high percentage of methane, CH4 (50-70%), making it susceptible to an energy recovery through combustion engines, boilers, turbines or, either alone or mixed with other fuel.
The controlled process of anaerobic digestion is one of the most suitable for reducinggreenhouse gas emissions, energy use of organic waste and the maintenance and enhancement of fertilizer value of the products processed.
Anaerobic digestion can be applied, among others, livestock waste, agricultural, as well as waste from processing industries such products. Between residues may be mentioned slurry, manure, crop residues or crop surpluses, etc. These wastes can be treated independentlyor together, by what is called co-digestion. The anaerobic digestion process is also suitable for treating waste water high organic load, such as those produced in many food industries.
The benefits associated with anaerobic digestion are: significant reduction of odor, mineralization, renewable energy-production( if the gas energy is used and replace a fossil fuel), emission reduction ofgreenhouse gases resulting from the reduction of uncontrolled emissions of CH4 (which produces a greenhouse effect 20 times greater than CO2), and reduction of CO2(saved by replacing fossil energy).
Anaerobic digestion may be carried out with one or more residues with the only premise that are liquid, containing fermentable material, and that have a relatively stable composition and concentration.Co-digestion is an alternative technology that can solve problems or deficiencies of a waste if they are offset by other features.
Biogas composition depends on the substrate digested and the type of technology used, it can be:
-50-70% of methane (CH4).
-30-40% of carbon dioxide (CO2).
- ≤ 5% hydrogen (H2), hydrogen sulfide (H2S) and other gases. Because of its high methane content, it has acalorific value somewhat larger than half the calorific value of natural gas. A biogas with a methane content of 60% has a calorific value of about 5,500 kcal/Nm3 (6.4 kWh/Nm3).
That is, except for the H2S content, is an ideal fuel. [4]

PROCESS OF BIOGAS PRODUCTION

Biogas production bacteria are a long group of complex and...