energy from organic waste biogas plants · waste to energy conference –06-07/11/2017 –istanbul,...

Waste to Energy Conference – 06-07/11/2017 – Istanbul, Turkey 1

Michael Köttner

Energy from Organic Waste – Biogas

Plants


• Know-how transfer (international workshops, conferences, study

tours, training)

• Technical support especially with

dry digestion, lagoon technology,

small scale installations

• Contacts to experts in planning,

design and construction

• Contacts to specialized

companies

• Networking with members

in different regions, nationally

and internationally

Activities of IBBK related to biogas technology

2


What is biogas?


Methane CH4 50 – 80 %

Carbon dioxide CO2 40 – 50 %

Water Vapour H20 0 – 20 %

Nitrogen N2 0 – 10 %

Oxygen O2 0 – 2 %

Hydrogen sulphide H2S 0 – 1 %

Hydrogen (hydrolysis) H2 0 – 1 %

Ammonia NH3 0 – 1 %

Biogas definition


Biogas definition

• Biogas is produced through the anaerobic degradation of organic

material by microorganisms

• Framework conditions for good production:

• Anaerobic condition → absence of air/oxygen

• The organic material must be readily available → no lignocellulose

• Sufficient moisture → at least 50 %

• Constant temperature (mesophilic: 38-42 °C, thermophilic: 50-55 °C)

• Constant feed quality


Biogas usage methods

Source: Fachverband Biogas


Feedstock for biogas production in Germany

2% 3%

44%

13%

48%

77%

6% 7%

% by weight % by energy input

Industrial and agricultural residues

Energy crops

Liquid and solid manure

Biowaste

7Source: Fachverband Biogas


Biogas potentials of various bio-waste



Biowaste treatment technologies


Process selection criteria

Utilization of biowaste

Material

Composting/Direct utilization

Material/Energetic

Anaerobic digestion

Energetic

Incineration


Process selection criteria

Water content

Structure

Co

mp

ostin

g / D

ry F

erm

en

tatio

n

Garden waste

Household-waste (rural)

Household-waste (urban)

Kitchen waste

Food waste

Catering waste

Slaughterhouse waste

Organic industrial waste

We

t Fe

rme

nta

tion

tion

Source: Wiemer & Partner 1994


Process comparisons

Wet fermentation Dry fermentation

Continuous processDiscontinuous/Batch process



Biogas producing techniques






Continuous feeding and

removal of small

quantities of substrate






During the digestion the

substrate is neither

added nor removed

from the digester





Wet fermentation of Biowaste

Advantages:

Good separation of

organic and impurities

Good substrate digestion

Good suitability for commercial

biowaste

Disadvantages:

× Complex (preparation)

× High energy consumption

× High wear

× Sedimentation

× TS approx. 12% or less

Energy requirement:

Approx. 10% of the plant’s electricity production

Minimum input: approx. 10 000 t/year

Maximum input: approx. 400.000 t/year

Gas production: approx. 100-130 Nm3/tFM

Others: mostly external hygienisationwww.bta-international.de


Dry fermentation of Biowaste

Advantages:

If modular → only 1 module is

affected in case of process

problems

High loading volume

High solids content: 30-40% TS

Disadvantages:

× Emission during batch loading

× Struvite deposits in the percolate

system

× Lower productivity

Energy requirement:

• Approx. 3-5% of the plant’s electricity production

• Fuel for wheel loaders

Minimum input: approx. 5 000 t/year

Maximum input: approx. 150.000 t/year

Gas production:

approx. 70-100 Nm3/tFM

→ longer operation for more uniform gas quality

Others: necessary hygienisation by composting


Design parameters for a 1 MW wet digestion plant

• Input

• Expired foodstuff 15.000 Mg/a

• Water 3.450 Mg/a

• Mixed waste 2.000 Mg/a

• Oil and fat 2.850 Mg/a

Total input 23.300 Mg/a

• Output

• Digestion Residue 17.350 Mg/a

• Biogas 3.350 Mg/a

• Packaging and Metals 2.250 Mg/a

Total output 22.950 Mg/a

• Energy

• Electrical energy 6,70 Mio kWh/a

• Thermal energy 7,00 Mio kWh/a


Exemplary Dates of Biowaste Treatment

Hamburg, Germany

• 07.03.2005: Submission of application

• 01.07.2005: Permit granted for construction

• 15.07.2005: Foundation of BIOWERK Hamburg GmbH & Co. KG

• 10.08.2005: Begin of construction on site

• 17.02.2006: Permit granted for operation

• 15.03.2006: First engine test with Biogas

• 24.04.2006: Official opening of the plant

• 17.07.2006: Start of the operating test


Operational problems; important issues


Particle size reduction

Extracting organic material from packaging

Impurities separation

Pretreatment of the feedstock in wet digestion


Inhomogeneous feedstock problems

• Dishes, cutlery, etc..

• Plastic bags

• Bones, egg and seashells

• Glass, etc..

Issues: mechanisms blocked or broken by material

Solution : separation of impurities

Wet digestion: pre-treatment necessary

Dry batch digestion: less sensitive to impurities → post-treatmentSource: FINSTERWALDER UMWELTTECHNIK


Feedstock – Removal of impurities from a wet digester


Biological problems

Issues:

• Ammonia level is high

• Feeding too high or retention time too short (Buffer capacity)

• Lack of trace elements/high sulfur

• Inadequate mixing

• Fast temperature decrease e.g. due to failure in heating systems

• Inhibitors (disinfectant, antibiotics)

Solutions:

• Feedstock as constant as possible

• Periodic check of the biological parameters

• Supplement of trace elements

• Thorough inoculation of input substrates is essential


Biowaste digestion processes overview in Europe


Biowaste dry fermentation – Continuous process

Linde KCA/Strabag – process (Germany)• Horizontal concrete digester with several paddle

stirrers in row

• Requires thorough crushing and pretreatment of

organic wastes

• Max 25% DM

DRANCO – process (Belgium)• Vertical cylinder, throughout crushing of organic

wastes

• Mixing with already digested matter (1:6)

• Vertical passage from top to bottom though

cylinder

Kompogas – process (CH), Thöni (AUS)• Horizontal steel or concrete digester with long

axle paddle stirrer

• Requires thorough crushing and pretreatment of

organic waste

• Max 25% DM


Strabag Umweltanlagen GmbH (formerly Linde-KCA Umweltanlagen GmbH)

The dry digester built as a horizontally arranged, special-concrete, very

sturdy compartment


Organic Waste System (DRANCO)

• First plant built in 1984

• Vertical digestion: the material drops vertically by gravitational force


• The volume of each digester is

around 1300 m3

• Retention time in the digester is

about 14-20 days

Axpo Kompogas AG


Biowaste dry fermentation – Discontinuous process

Simultaneous wet-dry digestion

(agricultural and communal)• Helector and BAL, DE. Renergon, CH

Solid mater immersion process with

flexible cover (agriculture)• Erep, CH. Aria-Biogas, Naskeo, FR.

Wolferstetter, DE

Garage type digester (communal)• Inoculation of substrates and percolation with process

water (Biocell, DK. BEKON, Bioferm, DeNaBa, DE.).

• Additional aerobic pretreatment (Kompoferm, DE.

Solon, DK. Pöttinger, AT)


Bekon Energy Technologies GmbH & Co.KG

• The standard module has 4 digesters

• Retention time in the digester is about 28-35 days

Source: Bekon Energy Technologies GmbH & Co. KG


BIOFerm GmbH

• Biggest plant: 8 digesters and a capacity of 750 kWel

• Retention time in the digester is about 4 weeks


Eggersmann Anlagenbau GmbH & Co. KG

• The standard module has 8 digesters

• Retention time in the digester is about 21 days → pre-process for

composting

Biogas plant Schweinfurt


Digestate management

Waste to Energy Conference – 06-07/11/2017 – Istanbul, Turkey 35 5

Use of biogas digestate

Digestate can be spread on the fields

• Before the land application the

feedstock/digestate must be

hygienized

• EU animal byproduct regulation, national

biowaste ordinance

Improved Fertilizer

• Avoids nutrient losses

• Reduces burning effect on plants

• Improves flowing properties, plant

compatibility and health

• Reduces germination ability of weed seeds

Environmentally sound

• Reduces the intensity of odor

• 3 folded emission reduction effect avoidance

of methane, laughing gas and ammonia

• Reduces the wash out of nitrate through better fertilizer management

• Recycles organic matter and nutrients


Upgrading of the digestate

Drying PelletizingLiquid-solid separation

Mineral Organic FertilizerComposting


Technical and financial success factors


Technical success factors for biowaste digestion systems

• Substrates need to be suitable for digestion

(stackable, structured, contaminant free)

• Not suitable for the treatment of hazardous wastes

• Thorough inoculation of input substrate is essential

• Active bacteria have to be transported to the substrate (dry

digestion), fresh biomass is transported to the bacteria (wet digestion)

• Digestion process has to support the development of appropriate

bacteria

• Applied technology has to suit local conditions, more than 60 % local

sourcing possible

• Plant size has to be designed according to available quality and quality

of input substrates

• Modular design allows future enlargement of the plant


Financial success factors for biowaste digestion systems

• Continuous supply of suitable substrate

• Fixed long term waste disposal contracts

• Availability of trained and motivated personnel

• Access to the electricity grid at reasonable rates

• Biowaste disposal fees, e.g. in Europe 20 – 120 €/t

• Revenue from biomethane or electricity sales

• Possibility to utilize excess heat from CHP unit

• Revenue from sales of compost or dried digestate as secondary fuel

• Communal projects are largely not profit driven: payback 15 to 20

years

• But, …. bio-methanisation is the only waste treatment technology with

a positive energy and revenue balance


Example investment costs


Example capital costs

Depreciation Years

Building 20

Equipment 10

Gas utilization 8

Mobile machineries 7


Example operational costs


Example specific treatment costs


Thank you for your attention!

Michael Köttner

International Biogas and Bioenergy Centre of Competence IBBK

Am Feuersee 6 • 74592 Kirchberg/ Jagst • Germany

Phone: +49. 7954. 926 203 • Fax: +49. 7954. 926 204

[email protected]

[email protected] • www.ibbk-biogas.com

energy from organic waste biogas plants · waste to energy conference –06-07/11/2017 –istanbul,...

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