Dry Anaerobic Digestion (AD) for High Solids Manures

Fußzeile

Dry AD for High Solids Manures

Norma S. McDonald

Waste to Worth Conference – April 5, 2013

PRESENTATION HIGHLIGHTS

• High solids feedstock characteristics and

market dynamics

• European research on operating plants

• In-depth look at dry continuous digestion

• Example economics

DILUTED, SAND-LADEN

STRAW-LADEN

PARTIAL

AGED, LEACHEDCONSISTENT

MANURE VARIES FROM SITE TO SITE

WET

AND

VERY

WET

DRIER AND

VERY DRY

LESS WATER,

LESS CAPACITY REQUIRED –within ammonia concentration limits

NOMINAL 1 MW ENERGY POTENTIAL

ANIMALS NUMBER

MANURE

TONS/YR

TOTAL

SOLIDS

FRESH

AT 5% TOTAL

SOLIDS

AT 12%

TOTAL

SOLIDS

AT 35%

TOTAL

SOLIDS

Beef Cows 10,600 45,580 35% N/A 1,746,876 598,929

Dairy Cows 4,800 182,646 8% 4,800,000 2,000,000 685,714

Hogs 60,000 109,588 5% 2,304,000 960,000 N/A

Chickens 1,050,000 49,823 25% 3,273,381 1,363,909 467,626

REQUIRED WORKING CAPACITY (GAL)

20 DAY RETENTION

ENERGY CROPS … AND DRY

CROP RESIDUALS

COMPARING

METHANE YIELD

ON A VOLATILE

SOLIDS BASIS

HIGHEST:

Barley, Triticale, Be

ets, Alfalfa, Rhubar

b, Rye, Grass, Maiz

e

COMPARING METHANE

YIELD PER ACRE

HIGHEST:

Potatoes, Maize, Beets, Kale,

Sorghum, Alfalfa

NET ENERGY YIELD PROVIDES AN INDICATION OF

SUSTAINABILITY

But ~50% of energy requirement is now fertilizer manufacturing

Presented at

European Biogas workshop and study tour

The Future of Biogas in Europe III

14th -16th of June 2007

University of Southern Denmark, Niels Bohrs Vej

9, 6700 Esbjerg

Esbjerg - Denmark

Comparison of 41 Austrian digestion plants processing manure

and energy crops – 2005

Comparison of 41Austrian digestion plants

processing manure and energy crops – 2005

*The data for DRANCO Farm was not included in the Study and are from OWS records

Installation 1 Installation 2 DRANCO-FARM Nüstedt

500 kWel 1 MWel*

Energy crops t/year 9 500 11 000 10 500 21 000

Manure t/year - 7 300 830 1 700

Total input t/year 9 500 18 300 11 330 22 700

Installed electrical power kWe 500 1000 500 1000

Reactor volume m³ 3000 3850 1200 1200

Temperature °C 49.5 39 55 55

Retention time days - 77 29 20

Loading rate kg VS/m³/d - 4.4 9.7 16-17

Biogas productivity Nm³/m³R/d 1.72 2.86 6.0 10.4

TS-content reactor % < 10 < 10 15-16 15-16

*The data for 1 MW was not included in the Study and are from OWS records

Biogas from energy crop digestion / IEA Bioenergy

Task 37

R. Braun / P. Weiland / A. Wellinger (2009)

Fermentation gas-measuring program II

Comparison of 61 Digester Operations

P. Weiland u.a. / Fachagentur Nachwachsende Rohstoffe e.V.

* The data for 1 MW was not included in the Study and are from OWS records

Mesophilic

Dry

Thermophilic

Wet

Thermophilic

Dry

DRANCO-FARM

2009 2010*

# installations - 11 6 4 **

Reactor volume m³ 881-5 626 1 100-8 900 845-3 400 1 200 1 200

Loading rate kg VS/m³RV/d 1.1-9.8 1.8-3.4 1.9-4.8 9.7 15-16

Retention time days 35-289 80-164 78-163 29 20

3-5X Loading Rate

5X Digestion Efficiency

<1/4 Digester Capacity

DRANCO-FARM plant Nüstedt (Germany)

DRANCO Farm digesterC

S

T

R

3 X 250 KW GENSETS

Specific features of the DRANCO FARM procedure

ENERGY

CROPS

MIXER

PUMP

DIGESTATE

STORAGE

BIOGAS

USE

DRANCO-

FARM

DIGESTER

PUMPPUMP

ACTIVE

DIGESTATEINACTIVE

DIGESTATE

INTENSIVE

FERMENTATION

• Combined feeding, mixing and pump technology

• Recirculation of partially digested material from the upper cone area

and integral post-fermentation step in the conical bottom

DRANCO-FARM Plant Data

• Region: Bassum-Nüstedt

• Startup: 2006

• Capacity: 500 KW (until 2009)

• Expansion: in 2010 increased to 1 MW

• Substrates: Maize silage, chicken manure, grasses

• MT per year: 21,000 – 22,000 (silage, manure)

• TS % of Inputs: ca. 30% (no addition of liquid manure or water!)

• TS % in digester: 16-17%

• Operation: Thermophilic (55°C)

• Destruction: 75% of TS

• Biogas production: 185 Nm3/mt

~ 4,000,000 Nm3/ yr

• Methane Content: 54 - 56%

• Parasitic load: ca. 5-7%

CHICKEN MANURE

MAIZE SILAGE

GRASS SILAGE

WASTE MEAL


33

22

11

1 2 33

21.200 5.800 15.400Ton/year

Biogas

GAS STORAGE

ENGINE

GENERATORElectricity (1000 kW)

Heat (950 kW)

DRANCO-

FARM

DIGESTER

1.200 m³

EXTRACTION

PUMPSTORAGE

Inactive

residue

Active residue

DOSING UNITDOSING UNIT

DOSING SCREWDOSING SCREW

MIXING UNIT/

FEEDING PUMP

Energy crops (& manure)

To field

Digestate has NPK

similar to manure on

dry ton

basis, pumpable, spr

eadable


ECONOMIC DATA

2010 2011

Produced kWh electricity 7,899,090 8,728,924

Permitted power production 8,760,000 8,760,000

% of max capacity 90.2%* 99.6%

* First year operation as 1MW-plant

Experiences and Conclusions

• Study results prove the high efficiency of dry and continuous digestion of energy crops, high solids manures

• High and steady biogas productivity is achieved by:

– High TS content

– Thermophilic operating temperatures

– Optimal and consistent operating parameters

• Dry and continuous digestion of energy crops is:

– Technically possible

– Reliable and highly efficient

EXAMPLE

ECONOMICS

- 1

Poultry

Manure @ $10

tip fee

Energy Crop

@ $45

harvested cost

Electricity sold

at $0.10/kWh

Digestate sold

@ $10/ton

DSCR of 4.6

CALCULATING THE NET VALUE PER TON OF FEEDSTOCK

Value (cost) as Received TPY Value $/ton $/yr

Manure 10,000 10.00$ 100,000$

Energy Crop(s) 45,000 (45.00)$ (2,025,000)$

TOTAL 55,000 (35.00)$ (1,925,000)$

Variable Costs TPY Cost $/ton $/yr

O&M 55,000 (5.45)$ (300,000)$

Labor 55,000 (2.65)$ (145,600)$ TOTAL 55,000 (8.10)$ (445,600)$

Energy Value TPY Value $/ton $/yr

Manure 10,000 58.03$ 580,305$

Energy Crop(s) 45,000 77.37$ 3,481,829$

TOTAL 55,000 73.86$ 4,062,134$

Digestate Value (Cost) TPY Value $/ton $/yr

39,286 10.00$ 392,857$

NET VALUE PER INPUT TON (EBITDA)

TPY Value $/ton $/yr

55,000 37.90$ 2,084,391$

EXAMPLE

ECONOMICS

- 2

Bedded Pack

Manure @ no

cost

Energy Crop

@ $45

harvested cost

Electricity sold

at $0.10/kWh

Digestate @

no value

DSCR of 3.5

CALCULATING THE NET VALUE PER TON OF FEEDSTOCK

Value (cost) as Received TPY Value $/ton $/yr

Manure 45,000 -$ -$

Energy Crop(s) 10,000 (45.00)$ (450,000)$

TOTAL 55,000 (8.18)$ (450,000)$

Variable Costs TPY Cost $/ton $/yr

O&M 55,000 (5.45)$ (300,000)$

Labor 55,000 (2.65)$ (145,600)$ TOTAL 55,000 (8.10)$ (445,600)$

Energy Value TPY Value $/ton $/yr

Manure 45,000 38.69$ 1,740,914$

Energy Crop(s) 10,000 77.37$ 773,740$

TOTAL 55,000 45.72$ 2,514,654$

Digestate Value (Cost) TPY Value $/ton $/yr

39,286 -$ -$

NET VALUE PER INPUT TON (EBITDA)

TPY Value $/ton $/yr

55,000 29.44$ 1,619,054$

CURRENT SITUATION

• ~195 operating AD plants on/near North

American farms

• Limited to wet digestion

• >95% are dairy farms

UNMET MARKET OPPORTUNITY

• ~20,000 additional farms with solid and semi-

solid manures and crop residuals – >100X

the volume of volatile solids

Fußzeile

Organic Waste Systems, Inc.

Tel. 513-535-6760

Fax 513-233-3395

[email protected]

www.ows.be

Thank you!

Dry Anaerobic Digestion (AD) for High Solids Manures

Education

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