Biogas to Electricity and Heat (STG)

1
Biogas to Electricity and Heat (STG)

• Cheung, Leanne
• Kam, Stephen
• Samandari, Jeff
• Taiby, Awrang

2
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/cha
  pter1.html
• 2 http//www.eia.doe.gov/cneaf/alternate/page/e
  nvironment/chap2.html
• 3 http//www.votenga.ca/Common20Pages/Backgrou
  nderTextFiles/Animal_Waste_Management.htm

3
4 http//www.eia.doe.gov/cneaf/alternate/page/en
vironment/chap3.html
4
Sources of Methane 1,2

• largest natural source of methane is the world's
  wetlands
• landfills, coal mines, oil and gas operations
• Agriculture Manure

5
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/55033/550
  33final.htm

6
Cal Poly Covered Lagoon Project5

• 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

7
Possible Benefits

• Reduction of solid waste
• Odor control
• Reduction in land and water pollution
• Reduction of methane as greenhouse gas
• Economic profits

8
Design and Operation

• plus
• Amount of resources required for useable energy
  production?
• Estimates of energy production

9
Methane Production Technologies6

• 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.

6http//ari.calpoly.edu/images/4674020pub201.d
oc
10
Covered Lagoon Digester

• Biogas production from a covered lagoon digester
  and utilization in a microturbine

California projects recover methane and capture
odors by using innovative systems.
Covered Lagoon Digester System
7http//f3.grp.yahoofs.com/v1/UKh5Qr0suIfo5fsf5x
jXnexmVXkoPwk0JwVRyr8wQLMV4MrChO1ad5aAl8WcRBeuFY4O
63nOiS5Td_7AUnEKxmBVfuYeIZWSbCweyi6RZR4Q4DADEA/DWW
CPLagoonhandout41505.doc provided by Dr. Douglas
Williams, BioResource ang Ag. Dept., Cal Poly
11
Resources Required lt in California gt

• The total manure produced by dairy cows in the
  state of California is 33,000,000 tons/year.

12
Energy Production 7lt in California gt

• 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.

13
Resources Required 6 lt at Cal Poly gt

• 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 21 side slopes.

14
Resources 7lt at Cal Poly gt

• 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.

15
Energy Production 7 lt at Cal Poly gt

• 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.

16
Energy Production 6 lt at Cal Poly gt

• 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.

17
Energy Production lt at Cal Poly gt
Figure 2. Floating Lagoon Cover at the Cal Poly
Dairy 6
18
Microturbine 7lt at Cal Poly gt

• 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 maintaininga self-supporting flame.

Figure 1Microturbine Electric Generator System
19
Microturbine Performance Summary lt at Cal Poly gt
7
20
Methane Production Technologies lt at Cal Poly gt
6
21
Energy Production lt at Cal Poly gt
Figure 4 10 KW Engine-Generator Test 7
22
Economic Feasibility

• Cost of Methane Recovery System
• Amount of Energy Production
• Economic benefits
• Could it be economically viable?

23
Capital Costlt at Cal Poly gt 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

24
Estimates of energy productionlt at Cal Poly gt 6

• Worth approximately 10,000
• based on the measured biogas production and the
  rated efficiency of the micro-turbine, the
  completed methane recovery system will produce
• 52,000 kWh of electricity and
• 77,000 kJ of heat annually

25
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

26
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

27
Comparisons With Other Methane Recovery Biogas
Systems
28
Langerwerf Dairy8

• 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/Langerwer
  f_digest.htm

29
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
30
Langerwerf Dairy
31
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/B
  iomassW05124.pdf

32
Dairies Supported by DPPP
33
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
• 10http//www.wurdco.com/Press/Press20releases/c
  astelanellidairymethaneopening.htm

34
Castelanelli Dairy
35
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/News20Clips/meadowbroo
  k20press20release.htm

36
Meadowbrook Dairy
37
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/News20Clips/Modbegallo
  digester.htm

38
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

39
Gallo Farms Cottonwood Dairy
40
Common Types of Biogas Systems 13

• Covered Lagoon Digesters
• Used when lt 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

41
Future for Cal Poly

• Increase gas production efficiency
• Better gas trapping
• Heating of lagoon
• From exhaust heat of microturbine

42
Lets start the discussion
43
Sources
1 http//www.eia.doe.gov/oiaf/1605/ggccebro/cha
pter1.html 2 http//www.eia.doe.gov/cneaf/alter
nate/page/environment/chap2.html 3
http//www.votenga.ca/Common20Pages/BackgrounderT
extFiles/Animal_Waste_Management.htm 4
http//www.eia.doe.gov/cneaf/alternate/page/enviro
nment/chap3.html 5 http//www.westbioenergy.org
/reports/55033/55033final.htm 6http//ari.calpo
ly.edu/images/4674020pub201.doc
7http//f3.grp.yahoofs.com/v1/UKh5Qr0suIfo5fsf5
xjXnexmVXkoPwk0JwVRyr8wQLMV4MrChO1ad5aAl8WcRBeuFY4
O63nOiS5Td_7AUnEKxmBVfuYeIZWSbCweyi6RZR4Q4DADEA/DW
WCPLagoonhandout41505.doc provided by Dr. Douglas
Williams, BioResource ang Ag. Dept., Cal Poly
8 http//rcmdigesters.com/publications/Langerwe
rf_digest.htm 9 http//biomass.ucdavis.edu/page
s/newsletters/BiomassW05124.pdf 10
http//www.wurdco.com/Press/Press20releases/caste
lanellidairymethaneopening.htm 11
http//www.wurdco.com/News20Clips/meadowbrook20p
ress20release.htm 12 http//www.wurdco.com/New
s20Clips/Modbegallodigester.htm 13
http//www.environmental-expert.com/magazine/biocy
cle/october/article3.htm