Transcript Our title

Biogas to Electricity and
Heat (STG)
Cheung, Leanne
Kam, Stephen
Samandari, Jeff
Taiby, Awrang
Background
Methane (CH4):
-greenhouse gas (GHG) produced by organic decay
-contributes ~9% of the total greenhouse gases [1]
-5-10 times the heat-trapping capacity of CO2 [2]
(21 times by other estimates) [3]
-is increasing in the air at double the rate of CO2 [2]
[1] http://www.eia.doe.gov/oiaf/1605/ggccebro/chapter1.html
[2] http://www.eia.doe.gov/cneaf/alternate/page/environment/chap2.html
[3] http://www.votenga.ca/Common%20Pages/BackgrounderTextFiles/Animal_Waste_Management.htm
[4] http://www.eia.doe.gov/cneaf/alternate/page/environment/chap3.html
Sources of Methane
[1,2]
largest natural source of methane is the world's
wetlands
landfills, coal mines, oil and gas operations
Agriculture: Manure
Manure
Stinks!
In California:
33,000,000 tons/year just by dairy cows
Contributes to land and water pollution
[5] http://www.westbioenergy.org/reports/55033/55033final.htm
Cal Poly Covered Lagoon
Project[5]
BioResource and Agricultural Engineering

Dr. Douglas Williams
Partners: CSU-ARI, Capstone Micorturbines
Goal: To obtain as much energy as possible
from dairy cow waste for reuse in the dairy
Anticipates greenhouse gas credits will be
available to the dairy
Possible Benefits
Reduction of solid waste
Odor control
Reduction in land and water pollution
Reduction of methane as greenhouse gas
Economic profits
Design and Operation
plus
 Amount of resources required for
useable energy production?
 Estimates of energy production
Methane Production Technologies[6]
A number of methane-producing technologies
have been developed and could be
considered for dairy manure.
The choice of the most appropriate
technology is dependent upon specific waste
characteristics.

Packed bed and up-flow anaerobic sludge blanket
digesters (used for soluble organic wastes).

Covered lagoons (used at dairies) success rate,
78%

Plug flow, success rate, 37%,

Complete mix digesters, success rate, 30%.
[6]http://ari.calpoly.edu/images/46740%20pub%201.doc
Covered Lagoon Digester
Biogas production from a covered lagoon digester
and utilization in a microturbine
Lagoon-Based Systems
Anaerobic Digestion at Dairy Farms
California projects recover methane and
capture odors by using innovative systems.
Covered Lagoon Digester System
[7]http://f3.grp.yahoofs.com/v1/UKh5Qr0suIfo5fsf5xjXnexmVXkoPwk0JwVRyr8wQLMV4MrChO1ad5aAl8WcRBeuFY4O63nOiS5Td_7AUnEKxmBVfuYeIZWSbCweyi6RZR4Q4DADEA/
DWWCPLagoonhandout41505.doc provided by Dr. Douglas Williams, BioResource ang Ag. Dept., Cal Poly
Resources Required
< in California >
The total manure produced by dairy
cows in the state of California is
33,000,000 tons/year.
Energy Production [7]
< in California >
If the total manure produced by dairy
cows in the state of California could be
converted to methane, the theoretical
energy production would be 20 trillion
BTU which would be enough to power a
200-megawatt power plant.
Resources Required [6]
< at Cal Poly >
The storage lagoon


has a volume of 19,000 cubic meters,
which translates to 50 to 90 days of storage,
depending upon the water used by the dairy.
The methane recovery (new primary)
covered lagoon is located next to the storage
lagoon.




has a volume of 14,400 cubic meters,
has approximate surface dimensions of 80 meters
x 65 meters.
The depth varies from 5.2 meters to 3.7 meters
with 2:1 side slopes.
Resources
[7]
< at Cal Poly >
The Cal Poly Dairy is located adjacent to the Cal Poly
campus in San Luis Obispo, California.
The dairy presently milks 180 cows with a total population
of over 350 animals.
Most of the herd is housed in freestall barns.
About 90 percent of the manure is deposited on concrete,
Flushed through a solids separator, and
Pumped into a 14,400 cubic meter covered lagoon
digester.
Energy Production
[7]
< at Cal Poly >
Floating cover is a reinforced polypropylene
material with Styrofoam floats to channel the
biogas to the gas manifold.
Approximately 300,000 to 400,000 liters of
flushed manure containing ½ % solids and
4000 mg/l COD are loaded daily into the
digester resulting an HRT of 40 days.
After exiting the lagoon the COD of the
effluent has been reduced to 1000 mg/l
resulting in much less odors.
Energy Production [6]
< at Cal Poly >
As the manure is anaerobically digested
by bacteria located at the bottom of the
lagoon, up to 100 cubic meters of
biogas is produced daily and collected
beneath a special floating cover.
Energy Production
< at Cal Poly >
Figure 2. Floating Lagoon Cover at the Cal Poly Dairy [6]
Microturbine
[7]
< at Cal Poly >
 This biogas, containing 70 % methane, is then piped to
the gas handing system where it provides fuel for a 30
kW
microturbine electric
generator as shown
in Figure

The biogas is being
continuously flared
and is maintaining
a self-supporting flame.
Figure 1:Microturbine Electric Generator System
Microturbine Performance
Summary
< at Cal Poly >
[7]
Methane Production
Technologies
< at Cal Poly > [6]
Energy Production
< at Cal Poly >
Figure 4: 10 KW Engine-Generator Test [7]
Economic
Feasibility
Cost of Methane Recovery System
Amount of Energy Production
Economic benefits
Could it be economically viable?
Capital Cost
< at Cal Poly >
[6]
 Approximately $225,000 for the costs of

this methane recovery system including
the lagoon construction
 flexible cover
 influent piping
 gas handling
 Micro-turbine system
 associated labor and engineering

Estimates of energy
production
< at Cal Poly > [6]
 Worth approximately $10,000

based on the measured biogas production
and the rated efficiency of the microturbine, the completed methane recovery
system will produce
52,000 kWh of electricity and
 77,000 kJ of heat annually

Profit Calculation
[5]
Cal Poly electricity bill for dairy production
 $3,000/month
Annual electrical usage for dairy production
= ($3,000/month)*(12month)
=$35,000
Electricity Profit = (52,000kWh/yr)*($0.12/kwh)
= $6,240/yr
Process Heat Profit = (77,000 kJ/yr)*($0.048/kJ)
= $3,760/yr
Total Profit = Electricity Profit + Process Heat Profit
= $6,240/yr + $3,760/yr
=$10,000/yr
Calculation continue…
Percent Saving on Electricity for Dairy
Product per Year
=($10,000/yr)/($35,000/yr) = 28%
# of years to Recover the cost of
methane system
=($225,000)/($10,000/yr)
=22.5yr
Comparisons With Other
Methane Recovery
Biogas Systems
Langerwerf Dairy[8]
Uses a plug flow anaerobic digester
40 kilowatt output
In operation since 1982
Converted biogas into 5 million kWh
Production had dropped by 30% in 1997
Restarted in 1998 with new parts
[8] http://rcmdigesters.com/publications/Langerwerf_digest.htm
Langerwerf Dairy
Component
1982 Projected Life
1998 Remaining Life
Revised Estimate of
usable life
Concrete
20 years
10+ years
30+ years
Steel plumbing
20 years
10+ years
30+ years
Plastic plumbing
20 years
10+ years
30+ years
Greenhouse plastic
3 years
0
4 years
Greenhouse galvanized
steel
20 years
4 years
20 years
Gas collection bag
20 years
0
12 years
Engine – between
overhauls
2 years
4 years
4 years
Gas meter
10 years
10 years
10 years
Gas pump
5 years
4 years
4 years
Project life
20 years
10+ years
30+ years
Langerwerf Dairy
Dairy Power Production
Program [9]
Created in response to the California
energy crisis
Provides support in 2 ways:
Helps pay for the biogas systems
 Pays an incentive for the energy created

Supports 14 dairies (Cal Poly Dairy is
one of them)
[9] http://biomass.ucdavis.edu/pages/newsletters/BiomassW05124.pdf
Dairies Supported by
DPPP
Castelanelli Dairy
[10]
2rd biogas system launched under DPPP
Started in October 2004
Uses a covered lagoon
Costs $650,000
1500 cows
160 kW generator
Will hope to be a self-sustaining farm
Estimated savings of $275,000 annually from the
generated electricity
[10]http://www.wurdco.com/Press/Press%20releases/castelanellidairymethaneopening.htm
Castelanelli Dairy
Meadowbrook Dairy
[11]
4th biogas system launched under DPPP
1st biogas system under DPPP to use a plug
flow digester
Started in November 2004
Costs $800,000
2000 cows
Will be able to power its own facility and have
excess energy
[11] http://www.wurdco.com/News%20Clips/meadowbrook%20press%20release.htm
Meadowbrook Dairy
Gallo Farms Cottonwood
Dairy [12]
3rd biogas system launched under
DPPP
Started in October 2004
Costs $2 million
Over 5000 cows and 38,000 cows
across 5 dairies
Uses a 7 acre, 44 million gallon lagoon
[12] http://www.wurdco.com/News%20Clips/Modbegallodigester.htm
Gallo Farms Cottonwood
Dairy
300 kW generator
Generates up to 2,500,000-kilowatt
hours per year
Powers 25% of the plant
Heat generated saves 145,000 gallons
of propane each year
Estimated savings of $275,000 annually
from the generated electricity and heat
Gallo Farms Cottonwood
Dairy
Common Types of Biogas
Systems [13]
Covered Lagoon Digesters


Used when < 2% of the waste is solid
Stores waste in a deep lagoon and traps escaping biogas
with a large floating cover
Complete Mix Digesters



Used when 3-10% of the waste is solid
Heats and mixes the waste in an engineered tank
A cover is placed over the digester to trap the biogas
Plug Flow Digesters


Used when 11-13% of the waste is solid
Waste is pushed through a long, linear trough; methane is
created and trapped inside an expandable cover
[13] http://www.environmental-expert.com/magazine/biocycle/october/article3.htm
Future for Cal Poly
Increase gas production efficiency
Better gas trapping
 Heating of lagoon


From exhaust heat of microturbine
Let’s start the
discussion
Sources
[1] http://www.eia.doe.gov/oiaf/1605/ggccebro/chapter1.html
[2] http://www.eia.doe.gov/cneaf/alternate/page/environment/chap2.html
[3] http://www.votenga.ca/Common%20Pages/BackgrounderTextFiles/Animal_Waste_Management.htm
[4] http://www.eia.doe.gov/cneaf/alternate/page/environment/chap3.html
[5] http://www.westbioenergy.org/reports/55033/55033final.htm
[6]http://ari.calpoly.edu/images/46740%20pub%201.doc
[7]http://f3.grp.yahoofs.com/v1/UKh5Qr0suIfo5fsf5xjXnexmVXkoPwk0JwVRyr8wQLMV4MrChO1ad5aAl8W
cRBeuFY4O63nOiS5Td_7AUnEKxmBVfuYeIZWSbCweyi6RZR4Q4DADEA/DWWCPLagoonhandout41505.d
oc provided by Dr. Douglas Williams, BioResource ang Ag. Dept., Cal Poly
[8] http://rcmdigesters.com/publications/Langerwerf_digest.htm
[9] http://biomass.ucdavis.edu/pages/newsletters/BiomassW05124.pdf
[10] http://www.wurdco.com/Press/Press%20releases/castelanellidairymethaneopening.htm
[11] http://www.wurdco.com/News%20Clips/meadowbrook%20press%20release.htm
[12] http://www.wurdco.com/News%20Clips/Modbegallodigester.htm
[13] http://www.environmental-expert.com/magazine/biocycle/october/article3.htm