Transcript Biogas Alix Simnock Brooke Myones Carrie Senft Dan Cohn What is Biogas? • Clean, efficient source of renewable energy (1) • Made from organic waste • Produces methane • Anaerobic.

Biogas
Alix Simnock
Brooke Myones
Carrie Senft
Dan Cohn
What is Biogas?
• Clean, efficient source
of renewable energy (1)
• Made from organic
waste
• Produces methane
• Anaerobic digestion (2)
• Replaces non-renewable
energy
• Digested in an airtight
container
Why Have a Biogas Digester?
• Replaces fossil fuels and other
sources of nonrenewable
energy
• Simple, cost effective designs
• Highly available fuel supply
• Better usage of manure
- no longer polluting water
- no longer being burnt
• Saves money
• Decrease greenhouse gas
emissions
• Produces organic fertilizer
How Does it Work?
•
•
•
•
•
Manure mixed with water to create slurry
Slurry is put into airtight digester
Anaerobic decomposition
Methane created and collected
Effluent produced and removed
(1)
Methane
Biogas
O2
CO2
H2S
Amonio
Water, Excreta,
Organic Material,
Biodegradable
Waste
+
ENERGY
Anaerobic Environment
Water with 80-90%
less contaminants,
Organic Fertilizer
Hydrolysis,
Fermentation,
Acetogenesis,
Dehydrogenization,
Methanogenesis
(3)
Graphic courtesy of Raul Botero
Technical Requirements for
Biodigestor
pH
Temperature (4)
Time
Ratio of water to waste
Ratio of carbon to nitrogen (5)
Fats and Grease
Food Processing Waste
Cultivation Waste
Whey (without salt)
Manure
Biomass
Relative Biogas Production
(3)
Effluent
• Fertilizer (6)
• Only 90% pathogen free
• Sulabh Effluent
Treatment
-sedimentation
-filtration
-UV radiation (7)
• Tilapia pond (8)
Digester
Influent
Digester
Effluent
Percent
Reduction
USEPA
Limit
CIIU*
Limit
COD
(mg/L)
2968
472
84.1%
125
500
BOD
(mg/L)
467
96.2
79.4%
25
200
TSS
(mg/L)
2209
319
85.6%
35
200
Turbidity
(NTU)
1818
172
90.5%
50
TKN
(mg/L)
306
166
45.7%
15
82.2
43.9%
Increase
2
15.4
13.6%
Increase
10
NH4-N
(mg/L)
PO4-P
(mg/L)
46.1
13.3
50
(3)
Scrubber
• H2S - hydrogen sulfide
– Corrosive to metal parts of generator
– Component of biogas
• Steel wool scrubber
(9)
Where Has it Been Used?
SMALL SCALE DIGESTERS:
10,000,000 in China
5,000,000 in India
40,000 in Cambodia
5,000 in Vietnam
3,000 in Colombia
500 in Costa Rica
(3)
Is it Successful?
• China: Yes! Helped
with energy
shortage problem (10)
• Costa Rica: Yes! Big
in rural areas (1)
• Middle East: Yes!
Helped improve
health and safety
conditions (6)
• Most successful in
rural areas
Designs/Models – China Fixed Dome
(11)
Design/Model – India Floating Cover
Gas Outlet
Floating
Gas Cover
Mixing
Pit
Outlet Pit
Slurry
Inlet Pipe
Fluid Level
Partition
Wall
(12)
Designs/Models- Santa Fe Women's
Group –Costa Rica
• Halting deforestation
• Use of cow manure
• Produces energy for
cooking
• 1.9 meters deep *1.5
meters wide * 3 meters
long biodigester
• 2:1 ratio of water to
manure (1)
Calculations
100 goats’ and 15 people’s waste can produce 10 m3 of
biogas ( 3 )
1 kW generator can run on 5.64 m3 of biogas for 12 hours
per day
6 kW generator: 33.84 m3 for 12 hours/day
(33.84 m3) * (1 / .4 m3/kg biomass) = 84.6 kg horse manure
Calculations (continued)
30 yd3 dumpster filled to capacity 1-2 times per week
(30 yd3) * (27 ft3/yd3) = 810 ft3/dumpster
(810 ft3/dumpster) * (55 lbs/ft3 dry manure) = 44550 lbs
manure/dumpster
(13)
(44550 lbs/dumpster) * (1 kg / 2.2 lbs) = 20250
kg/dumpster
(20250 kg/dumpster) * (1 / 84.6 kg/day) =
239.36 days/dumpster
Calculations (continued)
30 yd3 dumpster filled to capacity (1 “pull”) 1-2 times
per week
Barn pays for hauler per month, based on number of
stalls- estimated $50-$75 dollars/stall, for 28 stalls
(1400 $/month) * (1 / 8 pulls per month) = $175/pull
(2100 $/month) * (1 / 4 pulls per month) = $525/pull
Each pull costs the barn between $175 and $525.
Our Recommendation
Biogas = yes:
-Carbon neutral, renewable fuel
-no net increase in atmospheric greenhouse gas
Considerations:
-Time
-Labor
-Construction cost
-Waste disposal
-Fuel source
-Temperature and pH monitoring
References
1 "Biodigester Design & Construction: Understanding the Basics of a Biodigester." Rural Costa Rica. 2007.
Rural Costa Rica. 5 Jun 2008
<http://www.ruralcostarica.com/biodigester.html?gclid=CIil8pW8yZMCFSemQQodyUMLjQ>.
2 “3.1.2. Biogas.” Sustainable Energy Technologies Solutions for Poverty Reduction in South Asia. InforseAsia: The International Network for Sustainable Energy. <http://www.inforse.org//asia/M_III_biogas.htm>.
3 Arnow, Josh. "bio gas." E-mail to Alix Simnock. 28 May 2005.
4 “Biogas Digesters.” Household Energy Options. Energy for Sustainable Development (ESD) Limited. 3 June
2008 <http://igadrhep.energyprojects.net/Links/Profiles/Biogas/Biogas.html>.
5 “The biogas plant-some technical considerations.” Bioconversion of Organic Residues for Rural
Communities. 1979. The United Nations University. 31 May 2008
<http://www.unu.edu/unupress/unupbooks/80434e/80434E0k.htm>.
6 Nagamani , B., and K. Ramasamy. "Biogas production technology: An Indian perspective." Indian Academy
of Sciences. Indian Academy of Sciences. 5 Jun 2008 <http://www.ias.ac.in/currsci/jul10/articles13.htm>.
7 Jha, P. K.. "Recycling and reuse of human excreta from public toilets through biogas generation to improve
sanitation, community health and environment." United Nations Asian and Pacific Center for Agricultural
Engineering and Machinery. United Nations Asian and Pacific Center for Agricultural Engineering and
Machinery. 5 Jun 2008
<http://unapcaem.org/Activities%20Files/A01/Recycling%20and%20reuse%20of%20human%20excreta%
20from%20public%20toilets%20through%20biogas%20generation%20to%20improve%20sanitation,%20c
ommunity%20health%20and%20environment.pdf>.
References (continued)
8 Todd, John. "T H E E C O - M A C H I N E: Design and Construction." Todd Ecological, Inc. - Solutions For
Water Planning and Management. 2007. Todd Ecological Design, Inc.. 8 Jun 2008
<http://www.toddecological.com/ecomachines/design.html>.
9 “Biogas Scrubbing System (Eliminating Corrosive Hydrogen Sulfide Gas).” Energy Farms Network:
Reliable Renewable Energy for a Post Carbon World. 2006. Post Carbon Institute. 3 June 2008
<http://www.energyfarms.net/node/401>.
10 "Sichuan's Home-Scalae Biogas Digesters". Mother Earth News. 6/5/08
<http://www.motherearthnews.com/Renewable-Energy/1981-05-01/Sichuans-Home-Scale-BiogasDigesters.aspx>.
11 "Current Project: Small-Scale Biogas in La Florida". Appropriate Infrastructure Delegate Group. 6/5/08
<http://www.aidg.org/outreach/laflorida_biogas.htm>.
12 Beckmann, Curt. "Home biogas system (original)." Appropedia. MediaWiki. 5 Jun 2008
<http://www.appropedia.org/Home_biogas_system_%28original%29>.
13 Jokela, Bill. “Manure Spreader Calibration.” University of Vermont Extension. 9 June 2008
<www.sera17.ext.vt.edu/Documents/BMP_manure_spreader_calibration.pdf>