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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%
DRANCO-FARM plant Nüstedt (Germany)
CHICKEN MANURE
MAIZE SILAGE
GRASS SILAGE
WASTE MEAL
DRANCO-FARM plant Nüstedt (Germany)
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
DRANCO-FARM plant Nüstedt (Germany)
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
www.ows.be
Thank you!