8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 1/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Type of digesters and

fermentation processes

Wet fermentation Completely mixing digester Plug flow digester

Drying fermentation Plug flow reactor Garage batch type digester

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 2/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Concrete digester withConcrete cover

Disadvantages:

- no integrated gas holder

- Digester revision difficult

- the concrete is not absolutely gas-tight

- difficult leak identification

 Advantages:

- controllable (solid feeding….)

- withstand certain pressures (20 mbar)

- simple repairing of the stirring system

- low heat loss

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 3/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Concrete digester with concrete cover

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 4/16Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

 Advantages:

- low-price alternative

- simple digester revision

- integrated gas holder

Disadvantages:

- wind- and weather sensitive

- not 100% gas-tight

- Difficult to indicate the gas

filling level

GmbH

flexiblerEPDM-Folienhaubengasspeicher

Flexible, EPDM-film gas

holder (balloon –type)

Concrete digesterwith single membrane cover

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 5/16

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 6/16Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Concrete digester withair supported double

membrane cover 

 Advantages:- simple digester repair

- integrated gas holder

- well weather proofed- easy to indicate the gasfilling level

Disadvantages:

- more expensive than one cover

- not 100% gastight

- permanent energyconsumption through air fan

GmbH

flexiblePE-Folie

Stuetzluft-geblaese

PVC-GewebefoliePVC tissue

reinforced filmFan for 

air 

support

Flexible EPDM-Film

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 7/16Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Concrete digester with air supported double membrane

cover 

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 8/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Combi digester(concrete and stainlesssteel)

Tragluftdach Gasmembrane

Feststoffeintrag

Gasraum

Gärsubstrat

Dichtmasse

Edelstahlwinkel

Edelstahblech

Isolierung

Rührwerk

Beton

Heizung

Mittelstützemit Tragbändern

Beton

Basis from concrete, ring from V4A 

 All pipes in stainless steel

Combination with double coverpossible

concrete tank which is

sunk at least partly

into earth

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 9/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Horizontal digester with paddle stirrer

 Advantages:

- digesting high solids content

- high loading rate possible- little short cut flow

- automatic sand drain

- complete mixing

- high digester productivity- Suitable for dry digestion

Disadvantages:

- high price

- only possible with after digester

- limited in size

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 10/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Horizontal digester with paddle stirrer

Steel orconcrete

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 11/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Steel digester

combination of material: steel

 /stainless steel

Reactor: ring in ringbeton container

Biogasanlage

Kompakt 150

Gesellschaft für umweltschonende Technologie

150 kW Gasmotor

Fermenter:

1.000 m³Arbeitsvolmen

Nachgär-lager:

2.200 m³

Vorgrube

75 m³

Gasspeicher200 m³

Fahrsilos

Biogasplant

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 12/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Automatical feed-in by gear 

pump, several times per day

Retention time

aprox. 15 days

Cereal,

maize corn

Mill /Squezee

Process water 

Biomassstorage

Lactic acidfermentationpH value 4500m3 volume =Aprox. 350tcereals

50% DS

Lipp biogas system

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 13/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Dry fermentation systems with percolationDry fermentation systems with percolation

Source: BEKON, 2002

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 14/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

GarageGarage typetype digester digester 

Source: BEKON, 2002

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 15/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007

Comparison between dry and wet fermentationComparison between dry and wet fermentation

more problematicLess problematic (batch process)Hygiene

Liquid manure technologyDung and/or compost technologyTech. application

HighLowEmissions

lowhighEnergy density

High (homogenization)Low (Recirculation of percolat )Process energy

Whole digester affectedonly single module affectedFailure

complex, multi-stages continuous

processes

Modular, 1-stage batch processPlant

Formation of sink-, swimming

layers and foam

Not applicableInterferences

HomogenisationRecirculation of percolat, flow, pre-

mixture

Technique

Pumpable susbstrate

(max. 13 % VS)

Fermentable substrate

( max 50 % VS)

Substrate

Liquid fermentationSolid fermentationCriteria

8/6/2019 01.3 Digesters Digestion[1]

http://slidepdf.com/reader/full/013-digesters-digestion1 16/16

Biogas Regions: Train the Trainers Seminar, Wolpertshausen, Germany, 28-29 November 2007