MINI BIOGAS PLANT - SRUSHTI
Friday, March 17, 2006
Monday, December 26, 2005
Friday, December 02, 2005
ENERGY FROM BIOMASS
Energy from Biomass is one of the most widely used options. With the availability of new technologies there are various means to convert biomass into energy efficiently.
The biogas yield from Gobar or cow dung is very low as compared to various other biomass, therefore there is a need to design biogas plants for digestion of other efficient material. The widely available vegetative biomass (usually weeds) and Kitchen waste form the important material for designing efficient biogas models. At the same time not compromising on food security issues, developing countries could also take up Energy Farming (Production of biomass on fields for energy utilization - beside food production and organic waste utilization). Anaerobic digestion and gasification technology are possibilities for Energy Farming.
I have developed a prototype mini-biogas plant called 'SRUSHTI' means creation. This model works with vegetative biomass (grass, leaves) and kitchen waste as raw material. It was created last year. This requires 2 kilograms of Kitchen waste and other green matter as feed, and releases about 2 cubic meters of biogas. Initially to activate dung of cattle should be added for introducing methane generating bacteria.
Features:
Digester: A GI sheet drum as digester, an inlet (feed) and an outlet (digested slurry) system.
Controlling the temperature of the digester: Regarding keeping the temperature of the microbes at 37 degree centrigrade there are three options. The other option is to heat water through a simple solar water heater and circulate the water in the drum through copper tubes used for air conditioners which is adopted in this design.
Requesting for suggestions to improve.
My name is Borja Diaz and I live in Spain. During the last 2 years I have been surfing the net, reading articles about alternative energy sources for producing heat and electricity and I was really impressed when I found your works on the internet.
I have some questions concerning your mini biogas plant SHRUSHTI. Everytime I look at it, I have the feeling that the lid cannot hold too much pressure and that it must be really dificult to get it so tight that the biogas doesn´t go out. Same applies for the holes for stirring the tank´s liquids.
I humbly want to share with you some modifications I made to your design (never tested, it´s just theory), hoping that they will be useful.
First I added a metal pipe that goes vertically from top to bottom. That pipe is held in the center of the tank by radial supports that allow the pipe to spin (rotate?). Attached to that pipe are several little propellers that stir the mix of solids and liquids inside the tank. On the top of the pipe there is a crankshaft that makes the pipe spin.
Secondly on the top of the tank I substituted the metal lid by a loose plastic bag resistant to corrosion. That way, the biogas reactions would take place in complete anaerobic conditions, and as the biogas is generated the bag would get filled
The upsides of my modifications are that it is much easier to create an airtight environment using plastic materials since they are cheap and require little qualification for reparing it: as simple as reparing a flat bicycle tire.
The problems with those modifications is that the plastic must be kept away from direct sunlight exposure in order to enhance it´s lifespan ( 2 or 3 years tops ) and it wouldn´t hold as much gas pressure as the former lid. For that problem I was thinking about using old truck tires as auxiliary gas reservoirs in cases when the gas input is much bigger that the gas output. The crankshaft may be an obstacle for the plastic bag as it gets filled with gas, but it can be easily solved by using a large pipe and adjusting the sealing device (flange clamps)
12TH FEBRUARY 2009