Okay, as a mental exercise (really because I can't afford to build the thing right now) I have been designing a prototype of the Clean Energy Bio-Fuels plant I mentioned earlier.

To make things simpler I've broken down the design into the component parts:

• Bio-gas Plant
• Bio-Diesel Plant

Now as you may remember, the idea is to create a plant that is as energy self-sufficient as possible while reducing the impact on the environment to the bare minimum, while producing quality fuels, and as I've discovered other products.

This entry will look at building the prototype Bio-Gas plant, the inputs that will be needed, the challanges faced and the outputs I expect to get out of it.

Bio-Gas Plant Prototype

Inputs:

• Bovine Manure
• Agricultural Waste (plant matter only)
• Kitchen Waste (vegetable matter only)
• Glycerol (A by-product of Bio-Diesel generation)
• Water

Outputs:

• Methane
• C02
• Hydrogen Sulphide (Rotten Egg Gas)
• Slurry (source material that has exhausted its ability to generate gas)
• Water (contanimated)
• Electricity
• Heat

Design of Prototype:

Reactor

The reactor is where the initial generation of the gas occurs. Manure, water, agri-waste and kitchen waste are combined in a drum and mixed thoroughly. The system works on a four month rotational batch process. At the beginning of the first month, one drum is connected to the first outlet pipe. At the beginning of the second month, the first drum is moved to the second outlet pipe and a fresh drum is connected to the first. By the time the fourth month is completed, the first drum will be exhausted and ready to be emptied and prepared with a fresh batch.

The Bio-Gas reactor will consist of the following:

• 4 200 Litre Drums
• 4 Pressure Gauges
• Tubing (to take gas from drums to gas scrubber)
• 4 Custom lids with gas outlet valves and pressure/temp information

Gas Scrubber

While methane can form anywhere up to 60% of the gas produced by the reactor, C02 and Hydrogen Sulphide are both produced in large quantities. Not only are these gases environmentally dangerous, they affect the combustability of the bio-gas and thus inhibit optimal operation of any power generation.

To prevent this, we need to build a Gas Scrubber. The idea is to filter the gas through several stages to ensure that any contanimants are stripped out of the gas before it hits storage/usage.

Ideally I would like to build a solution that involves re-using the C02 in the process of either bio-gas generation or bio-diesel. There are a variety of different ideas regarding this. The one I like the most is passing C02 through a bacterial solution that converts the C02 into methane, thus not only taking the C02 out of the equation, but increasing the yield of the system.

Scrubbing out the hydrogen sulphide could be even easier. I ran across this method on Freepatents online. Essentially this method involves pumping the gas through an alkalyne solution (such as the slurry that results from the initial processing) at a certain temperature. This captures the hydrogen sulphide in the slurry where it can be broken down as the slurry cures.

Once the C02 and Hydrogen Sulphide has been removed or converted it needs to be dried. Removing the last of the moisture ensures the maximum combusitibility.

Materials:

• Tubing to take the gas from the reactor to the scrubbing process.
• Container for bacterial C02->Methane process
• Tubing to take gas from C02->Methane process to slurry processing
• Tubing to take scrubbed gas

Slurry Treatment

Once the materials ability to generate gas has been exhausted it needs to be transferred into the slurry treatment plant. The idea is that the slurry will be turned into a nutrient rich natural fertiliser, as well as providing part of the treatment of the bio-gas.

I'm still trying to work this part of the process out. Essentially what needs to come out at the end is water and dry fertiliser.

Materials:

• 4 x 200 Litre Drums
• Drying Pit
• Storage Shed

So there it is, needs more work and probably won't survive real life, but it's a step.