Transcript PPT - SME
12th U.S./North American Mine Ventilation Symposium Reno, Nevada, USA, June 9 -11, 2008 Thermal Oxidation of Coal Mine Ventilation Air Methane (VAM) J. M. Somers USEPA, Coalbed Methane Outreach Program H. L. Schultz BCS Incorporated Presentation Overview • Background on VAM • Flow-reversal Oxidizer Technology • VAM Oxidation Demonstration History • WestVAMP • CONSOL Windsor Mine Demonstration • JWR Mine Demonstration • Technology Deployment Challenges • Technology Deployment Benefits • Conclusions Background on VAM • Methane is a powerful greenhouse gas • More than 20 times as potent as CO2 Mine safety regulations require gassy underground coal mines to assure that methane concentrations in the mine workings are maintained at safe levels • Well below the lower explosive limit (5% in air) Mines employ large scale ventilation systems to vent methane to the atmosphere Methane drainage can supplement ventilation Background on VAM • Ventilation air methane (VAM) is largest source of coal mine methane (CMM) emissions • • 54% of all U.S. CMM emissions in 2005 Capturing and using VAM is challenging Large airflows – 100,000 to 1 million cfm (47 to 470 m3/s) Low concentrations – 0.1 to 1.0%, typically 0.3 to 0.5% Variable, both flow and concentration Flow-reversal oxidizers in use worldwide for industrial air pollution control offer a solution Global VAM emissions (2002) • Emission % world Country China United States Ukraine Russia Australia (Bm3) 6.7 2.6 2.2 0.7 0.7 Total World 17.3 Total 38.7 15.0 12.7 4.0 4.0 Background on VAM • Technology options • Thermal (Biothermica, MEGTEC) • Catalytic (CANMET) Operational modes • • Oxidation only Oxidation with energy recovery (e.g., electricity generation) Available systems • Commercial project - MEGTEC Systems (DePere Wisconsin, USA) – • Demonstration planned - Biothermica (Montreal, Canada) – • http://www.megtec.com http://www.biothermica.com Prototype - CANMET Energy Technology Centre (Varennes, Canada) – http://www.nrcan.gc.ca/se/etb/cetc/cetc01/htmldocs/home_e.htm Flow-reversal Oxidation Technology Schematic of an Oxidizer Valve 2 Heat Exchange Medium Valve 1 Heat Exchanger Air & CH4 Valve 1 Air & C02, H20 & Heat* Heat Exchange Medium Valve 2 Valve #1 open = Valve #2 open = *Heat recovery piping not shown VAM Thermal Oxidation History • MEGTEC VOCSIDIZER 1994: Oxidation only - Thoresby Mine, UK 2001-2002: Oxidation and steam generation – Appin Colliery, Australia 2007: Oxidation and electricity generation – West Cliff Colliery, Australia 2007: Oxidation only – Abandoned Windsor Mine (CONSOL Energy), West Liberty, West Virginia • Biothermica VAMOX 2008 – Jim Walter Resources Mine, Brookwood, Alabama, USA • In planning stages • Active mine • MSHA approval received! JWR Mine Demonstration • Employs a single Biothermica VAMOX unit • Capacity: 30,000 cfm • VAM concentration: 0.9 percent • Greenhouse gas emission mitigation: >40,000 tonnes of CO2e per year • Revenues: Carbon emission reductions • Projected lifetime: > 4 years WestVAMP • West Cliff Ventilation Air Methane Project Startup: April 2007 Capacity: 250,000 m3/hour (150,000 scfm) of mine exhaust air VAM concentration: 0.9 percent Generation unit: steam turbine Electricity output: 6 MW Four VOCSIDIZER units • Ongoing project with two revenue sources Electricity Carbon credits traded in New South Wales trading scheme WestVAMP • West VAMP project site CONSOL Windsor Mine Demonstration • • • • Using diluted, drained CMM to simulate VAM Employs a single MEGTEC VOCSIDIZER unit Operates unattended Goals are to verify: Ability to maintain VAM oxidation System safety Operability and maintenance requirements under field conditions • Capacity: 30,000 scfm of simulated VAM • VAM concentration: 0.6 percent CONSOL Windsor Mine Demonstration CONSOL Windsor Mine Demonstration • Results Ability to operate on VAM concentration below 1 percent verified System safety features verified • Responded appropriately to upsets (e.g., power outage) Field operation and maintenance experience gained Technology Deployment Challenges • Lack of technology knowledge and field experience • Availability of supplemental methane to raise VAM inlet concentrations to near 1 percent To maximize energy output, and therefore energy production revenues • Most VAM concentrations exiting the mine are significantly below 1 percent) To maximize carbon emission reduction revenues • One study estimates that attractive payback times (3 to 6 years) can be achieved at VAM concentrations above 0.6 percent with carbon emission reduction sale prices at or above $10.00 per tonne CO2e Technology Deployment Benefits • Ability to mitigate the largest source of coal mine emissions worldwide • Capability to capture and beneficially use VAM’s dilute energy content Adds to energy security by beneficially using a currently wasted energy source • Multiple vendors should lead to cost competition that will drive down project capital costs Higher return on investment Shorter payback time Conclusions • Flow-reversal oxidation of VAM with power generation is a proven technology • Field demonstrations are multiplying • Potential global market for VAM oxidation and VAM-to-power applications is large • Emerging cost competitiveness should enhance project economics Thank You Jayne Somers U.S. Environmental Protection Agency Manager, Coalbed Methane Outreach Program Washington, DC, USA [email protected] www.epa.gov/coalbed H. Lee Schultz Manager, Environmental Programs BCS Incorporated, Laurel, MD, USA [email protected]