A COST EFFECTIVE SOLUTION FOR SMALL – SCALE BIOMETHANE

GENERATION

Jaroslav KÁRA,Zdeněk PASTOREK,Oldřich MUŽÍKResearch Institute of Agricultural Engineering,p.r.i.,

Prague,Czech Republic

Davide PAGANELLI,SAFE sri, Bologne, Italy

7th International Research and Development Conference of Central and Eastern European Institutes of Agricultural Engineering

(CEE AgEng)

8 – 10th June 2011, Minsk , BELARUS

INTRODUCTION

• Anaerobic digestion in Czech Republic is mainly used for treatment of :

1) livestok wastes (liquid or solid manure,fodder wastes,…)

2) sewage sludge (organic wastes from WWTP)

3) organic fraction of municipal solid wastes

4) food-processing wastes (distillery,brewery,sugar refinery,dairy,…)

5) purposely grown phytomass (maiz, sorrel, grass,…)

BENEFITS OF ANAEROBIC DIGESTION

THREE MAIN CONDITIONS FOR ANAEROBIC DIGESTATION IN AGRICULTURE

1-slurry from cowshed, 1a-slurry from other farms

2-tank for slaughterhouse wastes

3-tank for kitchen leftovers

4-sanitation unit for substrates 2 and 3 ( EU Decision No 1069/2009 )

5-storage pit for grains

6-mechanical treatment of grains (squeezing, crushing, scrapping)

7-storage pit and treatment for phytomass

8-fermenter with integrated gasholder

9-CHP unit

10-exceeding biogas flare

11-digestate storage tank

12-digestate dispatch

DIAGRAM OF ORDINARY BIOGAS PLANT COMPOSITION

BIOGAS EXPLOITATION

1) Direct combustion (heating, drying, cooling, hot service water heating,…)

2) Cogeneration (heat,electric power)

3) Trigeneration ( (heat, electric power,cool)

4) Fuel for gas engine or gas turbine

5) Fuel for vehicles

6) Source of hydrogen for fuel cells

7) Biohydrogen production

BIOGAS EXPLOITATION

8)BIOGAS REFINING UP TO PIPELINE REQUIREMENTS AND INJECTION INTO THE NATURAL GAS GRID

We focused on

GAS PROCESSING

- DESULFURIZATION

- DRYING (condensed water vapour removal)

- CARBON DIOXIDE REMOVAL

- BIOGAS COMPRESSING

SCHEME OF UPGRADING UNITE

FIG. 1

FIG. 2

FIG. 3

FIG.5

FIG.6

FIG.7

FIG.8

CONCLUSION

1)The prototype unit has been designed to process about 50 SCM/h of raw biogas, and to produce 25-30 SCM/h of clean, free, and green bio-CNG.

However, there is in principle no limit for the size, that could be reasonably increased up to 4-6 times with a less-than-proportional increase of the

costs.

2) The small and medium sized biogas plants have a better energetic balance than larger ones, but their higher relative investment costs influence negatively its economic efficiency. With regard to both parameters, medium sized biogas plants (500 - 2000 kW, or 300-1000 SCM/h) are the most effective.

3) Moreover, the main environmental objection to bioenergy is the costs and CO2 emissions due to biomass transportation to the digester.

4) The reason for these limits is that too large a digester, or too distant sources of biomass would imply a large fossil-fuel consumption for transportation, and a global damage to the environment.

5) The proposed unit can recover exceeding gas, that is currently wasted, in order to obtain a clean and renewable fuel.

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