Download - Landfill Gas Utilization
Landfill Gas Utilization
Hayley EberlyDepartment of Chemical EngineeringThe University of Texas at Austin C, 2007
BASF, 2007
Agenda
Landfill Gas Overview Environmental Effects of Landfill Gas Life of Landfill Gas Landfill Gas Utilization Technological Changes Potential Problems Questions
Flare Image, n.d.
Landfill Gas Composition
Landfill Gas (LFG) Overview
1 million tons of waste produces 432,000 ft3/day of LFG
Produced by Bacterial decomposition Volatilization Chemical reactions
Composed of different gases Heating value of 500 BTU/SCF
Half the heating value of natural gas
Edgar, n.d.Landfill Gas Primer, n.d.
Environmental Effects
Landfills are the 2nd largest human source of methane Represent 23 % of all methane produced Methane absorbs 20X more infrared radiation by weight than CO2
LFG releases carbon dioxide Landfill gas also contains…
Volatile organic compounds (VOC) Contribute to ozone formation
Hazardous air pollutants (HAP) Affect human health when exposed
Frequently Asked Questions, 2008
Landfill gas is piped to a plant and partially displaces natural gas usage.
Life of Landfill Gas
Methane Generated From, 2008
Trash is delivered to landfill.
The waste decomposes and produces landfill gas.
Landfill Gas Utilization
Cheaper than natural gas Refineries and petrochemical
plants account for 14% of the natural gas used as fuel by industry in the U.S.
Significantly reduces the amount of carbon dioxide and methane released into the atmosphere by landfills
Can reduce NOx emissions when mixed with methane
No equipment changes downstream from burner
Edgar, n.d.Landfill Gas Direct, 2005
Schematic of LFG System
Technological Changes
Install separate fuel train and gas spuds for LFG
Dual fuel - fed by separate gas lines that connect at an intake flow regulator valve
Larger valve openings for higher volumetric flow
Maintain natural gas fuel train and gas ring
Replace internal parts with corrosion-resistant materials
Treat LFG before entering boilerto avoid condensation and corrosion
Edgar, n.d.Uses in Industry, 2004
Schematic of a Natural Gas Co-fired Boiler
Potential Problems
Adiabatic flame temperature (AFT) Natural gas – 2300 K Landfill gas – 2100 K 50/50 mixture – 2200 K
Flame stability and burning velocity With good mixing in the combustor, LFG has comparable stability to methane Install UV sensors
Stable zone of combustion Smaller for LFG than methane Must ensure constant heating value or mix with methane
Corrosion Use corrosion-resistant materials Maintain temperature above dew point of corrosive materials
Preheat combustion air Insulate the stack
Edgar, n.d.
References
BASF. (2007). Retrieved November 22, 2008, from Linde Engineering Web site:http://www.linde-india.com/customerreference/FrmPlantDetail.aspx?CatId=11&&Iid=5
C, C. M. (2007, October 30). The Macho Response. Message posted tohttp://themachoresponse.blogspot.com/2007/10/bully-for-you.h
Edgar, T. F. (n.d.). Evaluation of Environmental Emissions for Combustion of Landfill Gas in a Texas Petrochemical Plant. Retrieved from University of Texas Web site: http://texasiof.ces.utexas.edu/PDF/Reports/FINAL%208%2019%20Landfill
%20Gas %20Feasiblity%20Analysis.pdf Frequently Asked Questions About Landfill Gas and How It Affects Public Health, Safety, and the Environment . (2008, July 2).
Retrieved November 23, 2008, from U.S. Environmental Protection Agency Web site: http://www.epa.gov/lmop/faq-3.htm
Landfill Gas Primer - An Overview for Environmental Health Professionals [U.S. Department of Health and Human Services]. (n.d.). Retrieved November 23, 2008, from http://www.atsdr.cdc.gov/hac/landfill/html/ch2.htm
An Overview of Landfill Gas Energy in the United States. (2008, June). Retrieved November 18, 2008, from U.S. Environmental Protection Agency Web site: http://www.epa.gov/lmop/docs/overview.pdf
Flare Image. (n.d.). Retrieved November 24, 2008, from State Energy Conservation Office Web site: http://www.seco.cpa.state.tx.us/re_biomass-urban.htm
Methane generated from Sioux Falls Regional Landfill to provide energy for POET ethanol plant. (2008). Retrieved November 23, 2008, from POET Web site: http://www.poet.com/news/showRelease.asp?id=115
Landfill Gas Direct Use. (2005, May 6). Retrieved November 24, 2008, from U.S. Environmental Protection Agency Web site: http://www.epa.gov/stateply/documents/events/may2005/hildreth0505.pdf
Uses in Industry. (2004). Retrieved November 24, 2008, from http://www.naturalgas.org/overview/uses_industry.asp
Questions
Additional Slides
Modern Sanitary Landfill
An Overview of Landfill, 2008
Production phases of typical landfill gas