Biogas Methane Explained

By Steve Last

Biogas methane is methane created from biologically created organic matter. The important thing to remember is that the term has entered common usage through the need to distinguish biogas derived methane from fossil fuel methane. Fossil fuel derived methane is known as 'natural gas'. Natural gas comes from mineral reserves, where it has been stored in the ground since its formation from living plants and animals hundreds of thousands of years ago. Natural gas/methane also comes sometimes from coal mines and coal measures which emit it.

So, in other words, biogas methane means 'green', 'renewable' methane, as opposed to natural gas which when burnt contributes to the greenhouse effect.

In addition to the biogas methane energy sources usually talked about, there are others which are not mineral gas created and these are either natural and un-natural in their origins, as follows:-

1. Gas being created naturally all the time in peat bogs and organic marine silts;

2. Methane produced in the stomachs of animals by the digestion of their foods (eg ruminants);

3. Biogas being created in farm slurry tanks etc, while farmers hold it waiting for dry weather when they can spread the manure/slurry on to their fields;

4. Landfill gas which is simply biogas created in landfills where the conditions are anaerobic.

If any sources of methane are emitted and rise from ground level into the atmosphere they are thought to be very potent causes of greenhouse warming. In fact, methane is about 20 times more active in absorbing the sun's heat, and causing global warming, than carbon dioxide.

Anaerobic decomposition in all these cases, produces methane biogas. At the same time it produces, carbon dioxide, some hydrogen, and other gases in traces. AD also produces a little heat, and a final product with a higher nitrogen content than is produced by aerobic fermentation.

The biogas production process which is usually inferred when people talk about biomethane is Anaerobic Digestion. This is a process which consists of feeding biomass to a large digester, in which methane-producing bacteria, under airless conditions, convert it into the energy-rich biogas.

The action of mixing and heating with the digester allows the bacteria to come into contact with the feedstock material, which provides food for the bacteria to multiply and convert the complex organic compounds into much simpler mostly soluble compounds. For example, sugars and starches, which then react in further stages giving off methane gas, which comprises about two thirds of biogas. The gas, a mixture of methane and CO2, is used for direct combustion in cooking or lighting applications, or to power combustion engines for motive power or electricity generation.

Methane (CH4) biogas technology is a renewable energy technology that uses various forms of biomass (animal dung, crop waste) and converts it into a useful energy source in the form of a gas (about 70% methane), via anaerobic microbial digestion. Methanogens are organisms that make methane via a unique metabolic pathway with unique enzymes. This produces a mixture of gases, primarily methane and carbon dioxide, and a nutrient-rich slurry. The CH4 rises into the gas holder where it is contained by a water seal. When the mixture of methane and air (oxygen) burn a blue flame is emitted, producing large amount of heat energy.

Methane biogas can be used for all the purposes in which natural gas is used, and can be used as the renewable equivalent of LNG as well.

Methane biogas has in the past been more expensive to produce that simply drilling for natural gas and pumping vast quantities of natural gas to our homes and industries. The biomethane needs "scrubbing" before it is clean enough to use in normal natural gas burning equipment. If it is not scrubbed, or not scrubbed adequately it will cause corrosion.

Methane biogas is about to become much more important as an energy source than it has been in the past, due to the ever rising cost of natural gas.

Thinking more about building a digester? Steve Last is web master for the fact filled Anaerobic Digestion Community web site where much more methane biogas and digester information is available.

Steve Last is also a regular contributor of dog breed related articles at The Dog Breeds Compendium.

Article Source: http://EzineArticles.com/?expert=Steve_Last

What is the Greenhouse Effect and the Importance of Methane to Climate Change

By Steve Evans

The greenhouse effect, also called the "greenhouse phenomenon" or "global warming", has recently been receiving a great deal of scientific and popular attention. The term refers to a cause-and-effect relationship in which "heat blanketing" of the earth, due to trace gas increases in the atmosphere, is expected to result in global warming.

By global warming we mean an increase in the average temperature of the planet. Actually global warming is rather a confusing term because global warming does not mean that everywhere will be hotter all of the time, it just means that on average the globe will be warmer.

Now we just mentioned that “heat blanketing” is taking place, and that this is due to trace gases in our atmosphere. There are a number of so called ‘trace’ gases, which simply means gases that are present in the atmosphere at low levels, such that there is only a trace present (a small amount in proportion to the other gases). So it is these trace gases that are producing an effect which is like wrapping the world in a blanket. Just like any blanket, it has a net effect which holds the heat in.

These trace gases are increasing as the result of human activities. Scientists know this. It is easily measured historically by analyzing things like pack ice which was deposited in layers which layers can be readily dated and go back hundreds of thousands of years.

Carbon dioxide (chemically shown as CO2, which is simply a chemist’s shorthand way of telling us that it is a molecule made up from two Oxygen (O) molecules to each Carbon (C) molecule), is a trace gas.

The principal gases in approximate order of importance, are carbon dioxide, methane, the chlorofluorocarbons (considered collectively) and nitrous oxide.

Carbon dioxide is the trace gas scientists believe is contributing most to the "heat blanketing" and currently receives the most attention.

However, Carbon Dioxide is not the only trace gas which is implicated in climate change and methane is another which some have estimated to be over a third as much as that of carbon dioxide.

Gas from natural sources, cows and other ruminants, and natural sources where natural decomposition by fermentation produces methane, all contribute to the blanketing which is the cause of the greenhouse effect.

However, human activity is also responsible for a lot of methane gas production and Municipal Solid Waste Landfills have in turn been recognized to be a source of methane which is contributing to the atmospheric buildup.

However, the magnitude of the landfill methane contribution and the overall significance of landfill methane to the greenhouse effect have been uncertain, and the subject of some debate.
But, as time goes on the evidence becomes stronger, and the fact of climate change is now accepted by the vast majority of scientists working in this field.

So, it appears that methane (using US waste generation data and remembering that the methane from United States landfills is a very large quantity) makes an important net contribution to the greenhouse phenomenon.

Landfill produces a lot of landfill gas which is largely methane. Measures to reduce landfill methane emissions are thought to be among the most economical steps which could be taken to address a component of this problem.

So now you know more about this subject, and we hope you appreciate the danger posed by uncontrolled climate change. We have explained, and hopefully ‘demystified’ some of these details – so now you can visit our web sites armed with enough knowledge to help you to find out more...

Steve Evans is a regular contributor of environment related articles. There are more essential details about climate change and the importance of methane at The Landfill Gas Web Site See also our New Blog about renewable power sources which do not cause global warming: Renewable Energy News