Landfill Gas Utilization - pptfun by hcj


									Landfill Gas Utilization

   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 (LFG) Overview

   1 million tons of waste produces        Landfill Gas Composition
    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
                                                                           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
Life of Landfill Gas

                                                                Landfill gas is piped to a
                                                                plant and partially displaces
                                                                natural gas usage.
                                   The waste decomposes
                                   and produces landfill gas.

 Trash is delivered to landfill.
                                                                           Methane Generated From, 2008
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

                                      Schematic of LFG System
                                                                         Edgar, n.d.
                                                           Landfill Gas Direct, 2005
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
   Larger valve openings for higher
    volumetric flow
   Maintain natural gas fuel train and gas
   Replace internal parts with corrosion-
    resistant materials
   Treat LFG before entering boiler
    to avoid condensation and corrosion
                                                Schematic of a Natural Gas Co-fired Boiler

                                                                                    Edgar, n.d.
                                                                        Uses in Industry, 2004
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.
   BASF. (2007). Retrieved November 22, 2008, from Linde Engineering Web site:
   C, C. M. (2007, October 30). The Macho Response. Message posted to
   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:
   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:
   Landfill Gas Primer - An Overview for Environmental Health Professionals [U.S. Department of Health and Human Services].
            (n.d.). Retrieved November 23, 2008, from
   An Overview of Landfill Gas Energy in the United States. (2008, June). Retrieved November 18, 2008, from U.S. Environmental
          Protection Agency Web site:
   Flare Image. (n.d.). Retrieved November 24, 2008, from State Energy Conservation Office Web site: http://
   Methane generated from Sioux Falls Regional Landfill to provide energy for POET ethanol plant. (2008). Retrieved November 23,
          2008, from POET Web site:
   Landfill Gas Direct Use. (2005, May 6). Retrieved November 24, 2008, from U.S. Environmental Protection Agency Web site:
   Uses in Industry. (2004). Retrieved November 24, 2008, from
Additional Slides
Modern Sanitary Landfill

                           An Overview of Landfill, 2008
Production phases of typical landfill gas

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