PROCESS

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  Ecologic loop

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  Ecological effects of combustion

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  Temperature in relation to the phases of wood combustion

Calculations

• Food waste has a higher solid content than municipal wastewater, meaning that it is a more efficient use of digerester volume aka the digester can be smaller.

• Peak methane production in a 15-day cycle, themophyllic digester was 10.8L/hr but averaged 4.8L/hr.

• 100 tons of “input” will create 30 tons of “output” for composting

• Biogas composition is about 67% methane (CH4), 33% CO2 - so heat capacity is 670 BTU/Ft3 burned.

• CH4 production rate (ft3/lb)= CH4% X Gas Production ( ft3/day) TS% X Feed (gal/day) X 8.34 lbs per gal

peak values near 8.5 ft3 CH4/ lb food waste. 5ft3/lb average.

1 ft3 CH4 at 67% methane = 670 BTUs and 13,400 BTUs = 1 kWh. this value is better than coal ( 10, 500btu/kwh)

• av. of 2,300 ft3 per day/ 1,000 ft3 digester volume

range (in ft3/day) = (1,100–3,200) with these figures, 4.79 kw/h of energy are created daily in a 1000ft3 digester! thats enough to run 48 100-watt lightbulbs continuously. These figures are the optimal output based on the chemical energy of the gas, not the conversion into electric energy by burning.

1000ft3= 28.3 cubic meters

Digester

1. There are certain minimum dimensions

2. It needs constant teperature

3. Position: above or below ground.

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