EPA-430-F-19-023

Ventilation Air Methane (VAM) Utilization
Technologies
Updated July 2019
U.S. EPA
Coalbed Methane
Why is VAM Mitigation Important?
Methane, the principal component of natural
gas, is often present in underground coal
seams and is a safety hazard to miners
because it is explosive in concentrations
ranging from 5 to 15 percent in air. Gassy
underground coal mines employ large-scale
ventilation systems to move fresh air into the
mine. These systems dilute methane released
into the mine workings as coal is extracted
and remove the gas from the mine, thereby
maintaining safe working conditions. In-mine
methane concentrations must be maintained
well below the lower explosive limit, so
ventilation air exhausts contain very dilute
concentrations of methane (typically less than
1 percent and often less than 0.5 percent).
However, because mine exhaust flow rates
are so high, ventilation air methane (VAM)
constitutes the largest source of methane
emissions at most mines.
Releasing VAM to the atmosphere wastes a
clean energy resource and produces
significant global greenhouse gas emissions.
Methane is a potent greenhouse gas with a
global warming potential more than 25 times
that of carbon dioxide. Deploying technologies
that destroy VAM emissions or convert VAM
into useful forms of energy (such as
electricity and heat) can yield substantial
greenhouse gas emission reductions.
Technologies Using VAM as Primary Fuel
Regenerative Oxidation and Catalytic
Oxidation: Regenerative Thermal Oxidation
(RTO) is the only commercially operational
technology capable of using VAM as a primary
fuel at methane concentrations below
1.5 percent. RTO and Regenerative Catalytic
Oxidation (RCO) have long been used as odor
and pollution abatement equipment in
manufacturing, printing and other industries,
and have now been successfully adapted to
oxidize methane in mine ventilation air.
Demonstrations of RTO and RCO VAM
abatement occurred in the 1990's and early
20QQ's, with implementation of the first
commercial VAM RTO project in 2007. In
total, at least six commercial RTO projects
have operated in Australia, China, and the
United States.
Available arid Developing Options for VAM
Utilization
•	VAM used as the principal fuel
-	Oxidation, with or without energy
recovery (Thermal or Catalytic)
-	Gas turbines - microturbines
(e.g., 30 kW) and full sized turbines
(>0.5 MW)
•	VAM used as a supplemental fuel
(i.e., combustion air)
-	Internal combustion engines
-	Turbines
-	Utility or industrial boilers
-	Hybrid rotary kiin/gas turbine
•	•••••
How does an RTO destroy VAM? Ducts direct
a slip stream of exhaust air from the fan to
the oxidizer. Air velocity is maintained in the
ducting by use of a fan that creates vacuum
pressure. This provides a steady flow of mine
ventilation air into the oxidizer, and also
ensures that there is not back pressure on the
shaft fan. When entering an RTO, gas
encounters a bed or column of heat exchange
material, usually ceramic media that has been
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preheated to the oxidation temperature of
methane (1000° C), The VAM enters the
oxidation chamber where it is oxidized and
releases heat, which is absorbed by the
second bed or column of heat exchange
material, heating the bed to 1000° C. This
heat sustains the auto-oxidation process
without requiring additional fuel input. Valves
and dampers repeatedly reverse the flow of
incoming VAM to keep the hot zone in the
center of the oxidizer. Catalytic and thermal
systems both operate on this principal,
although catalysts are intended to allow the
reaction to occur at lower temperatures and
also with reduced pressure drop across the
bed of heat exchange material. When VAM
concentrations are high enough, thermal
oxidizers can provide excess heat energy for
uses such as shaft heating and electricity
generation. Examples of commercial VAM RTO
projects include the West Cliff Colliery in New
South Wales, Australia, Verdeo McElroy VAM
Abatement Project at the Marshall County
Mine in West Virginia, and the Gaohe Mine in
China.
Verdeo McElroy VAM Abatement Project, Marshall
County Mine, West Virginia, USA (courtesy of
Sindicatum Sustainable Resources)
In addition to being the world's first
commercial VAM project operating from 2007-
2017, the West Cliff Ventilation Air Methane
Project (WestVAMP) developed by BHP
Billiton, was also the world's first commercial-
scale VAM-to-power project. The plant
consisted of VOCSIDIZER™ RTOs
manufactured by B&W MEGTEC Systems. The
plant generated 6 megawatts (MW) of
electricity using a steam turbine generator,
producing 300,000 MWh and reducing GHG
emissions by 2 million metric tonnes of C02
equivalent (tC02e) during its project life.
Fortman Clean Energy Technology Ltd VAM
Abatement Project, Gaohe Mine, Shanxi Province,
China (courtesy of Durr Systems)
The Verdeo McElroy VAM Abatement Project
commenced operation at the Marshall County
Mine in West Virginia in May 2012. The
project, developed by Sindicatum Sustainable
Resources and now owned by NextEra Energy
Marketing generates heat as methane is
destroyed. The project consists of 3 RTOs
manufactured by Durr Systems. Each RTO
has a capacity of 53,330 standard cubic feet
per minute (scfm) for a total plant throughput
capacity of 160,000 cfm (75 normal cubic
meter per second [Nm3/s]), which is 80
percent of the shaft flow. As of December 31,
2017, the project has registered 1,045,923
tC02e in emission reductions.
As of September 2018, the world's largest
operating VAM project is at the Gaohe Mine of
the LuAn Mining Group in Shanxi Province,
China. Developed by Fortman (Beijing) Clean
Energy Technology Ltd. of China, the VAM-to-
power project began operation in May 2015
with reported grid-connected power
generation of 8000+ hours per year and a
total throughput capacity of 700,000 cfm
(300 Nm Vs), utilizing 12 RTOs manufactured
by Durr. Heat produced by the oxidation
process is routed to a steam boiler which
generates sufficient steam for a 30-MW power
plant. In 2018, Fortman commissioned a
second VAM-to-Power project at a mine in
Yangquan, Shanxi Province, China. The
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project contains 6 RTOs with a combined
capacity of 350,000 cfm (150 Nm3/s) and
includes a 15-MW steam turbine generator
that will produce electricity. Heat produced by
the VAM project will replace heating from
coal-fired boilers during cold-weather months.
In addition to these two projects, China has
hosted several other VAM projects including
one at the Datong Mine in Chongqing, which
featured 6 MEGTEC Vocsidizers for a total
throughput capacity of 210,000 cfm
(104 Nm3/s).
Biothermica VAMOX™, Blue Creek Mine #4 Mine,
Alabama, USA (courtesy of Biothermica
Technologies Inc.)
In addition to Durr and B&W MEGTEC, other
manufacturers of VAM RTOs include:
•	Biothermica, a Canadian air pollution
control equipment supplier, manufactures
an RTO called the VAMOX™. A VAMOX™
unit was fully operational at the Blue
Creek No. 4 mine in Brookwood, Alabama
USA from 2009 through 2012. The
project employed a single unit capable of
handling 30,000 cfm or 14 Nm3/s. The
project was the first to operate at an
active underground coal mine in the
United States. Biothermica has reached an
agreement to install two large-scale
VAMOX™ units at the same mine in 2019,
each capable of handling 140,000 cfm -
which would make it the largest VAM
project in North America.
•	Gulf Coast Environmental Systems, LLC,
supplies the CH4 RTO™.
•	HEL East Ltd. of the United Kingdom,
which has tested a commercial-scale unit
at an operating coal mine.
•	The Commonwealth Scientific and
Industrial Research Organisation (CSIRO)
of Australia has developed the VAMMIT™,
a VAM mitigator that is a compact flow
reversal reactor with a newly-structured
honeycomb regenerative bed, resulting in
less pressure drop/energy consumption
and a smaller footprint. CSIRO has field
tested the VAMMIT™ at a mine in
Australia. Site trial results at a mine site
in Australia show that the operation of the
VAMMIT unit is self-sustaining at VAM
concentrations between 0.3 - 1.0 percent
CH4.
Catalytic technology for VAM abatement
operates in a manner similar to RTOs but
employs catalysts that enable it to operate at
lower temperatures. The catalysts are placed
with the heat exchange media in the bed
increasing the total column of material.
Although this lowered the oxidation
temperature compared to a similar-sized RTO
in early trials, it also resulted in lower VAM
throughput. However, research and
development have continued to address these
issues, and commercial deployment of RCOs
is expected in the near future.
•	Canada's CANMET Energy and Technology
Centre developed a prototype catalytic
VAM RCO called the CH4MIN™ using a
proprietary catalyst. Following bench-scale
and field demonstrations by CANMET,
Sindicatum Sustainable Resources
licensed the CH4MIN1" technology in
2007, and from 2008-2009, built and
successfully tested a 15 Nm'/s
commercial-scale CH4MIN™ in a
laboratory setting.
•	In 2015, Johnson Matthey, a United
Kingdom-based global chemical
manufacturer, introduced a new catalytic
system, COMET™, developed in
collaboration with Anglo Coal to address
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VAM emissions. COMET"'1 is a "once
through" system where the VAM stream is
passed through a heat exchanger to raise
the temperature of the gas to the desired
inlet temperature and then passed
through the oxidation reactor containing
the oxidation catalyst. Johnson Matthey
and Anglo Coal successfully tested the
COMET"'1 system at an operating mine in
Australia on VAM concentrations ranging
from 0.1-0.8 percent CH4.
•	CSIRO has been developing emerging
technologies for ultra-low concentration
VAM abatement, including photocatalytic
oxidation destruction under ambient
temperature and pressure conditions. Lab
scale tests have demonstrated successful
destruction of VAM at concentrations less
than 0.3 vol %CH4.
Lean-fuel Turbines: Generation of electricity
from VAM requires a rich and consistent CH4
stream. For most shafts, this will require the
addition of supplemental fuel such as drained
gas that can be blended with VAM to increase
the methane concentration to approximately
1 percent methane.
Lean-fuel gas turbines using VAM as the
primary fuel are close to commercial
deployment.
•	CSIRO has developed a lean-fuel gas
turbine, the VAMCAT M, which employs a
catalytic combustor to run on VAM
concentrations. CSIRO created a 25kWe
power generator demonstration unit and
field-tested it at an underground coal
mine of the Huainan Coal Mining Group in
China in November 2011. The
demonstration unit operated at a CH4
concentration of 0.8 percent.
Ener-Core Powerstation EC250, Attero Landfill,
Schinnen, Holland (courtesy of
Ener-Core, Inc.)
• Ener-Core produces the Powerstation
EC250 which uses a Flexturbine
microturbine to produce power directly
from VAM. The operating range is from
100% to as low as 1.5% CH4. The system
can run directly on low pressure, low
quality gases including VAM. A Power
Oxidizer replaces the combustor,
producing the heat to drive the turbine.
With low-Btu fuels including VAM, the fuel
is aspirated with air prior to the inlet and
oxidation, eliminating external
compression and accepting low pressure
gas. Ener-Core also makes the Power
Oxidizer 2 MW power station using a
Dresser-Rand turbine.
Technologies Using VAM as Supplemental
Fuel
Some technologies capable of using the
energy content of ventilation air exhausts as
a supplemental fuel in internal combustion
engines, turbines, or industrial boilers are
currently available.
One existing technology application entails
using VAM as combustion air, supplying
ancillary fuel to internal combustion (IC)
engines, turbines, or industrial and utility
boilers. In fact, use of VAM as combustion air
in IC engines has been commercially
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demonstrated. For example, the Appin
Colliery in New South Wales, Australia
implemented a project employing
54 VAM/coal mine methane driven internal
combustion engines to power generators that
produced 55.6 MW of electricity for the mine.
Using ventilation exhaust as combustion air in
large utility or industrial boilers has also been
demonstrated on a pilot scale at the Vales
Point Power Station in Australia. However,
using VAM for combustion air is limited by
geographic constraints: the facility must be
sited near the mine.
Another approach to using VAM as a
supplemental fuel involves an innovative
rotary kiln system that burns waste coal with
ventilation air methane or drained coal mine
methane. The mixed fuel is combusted in the
kiln, and the exhaust gases pass through a
specially designed air-to-air heat exchanger.
The heated clean air powers a turbine to
produce electricity. The waste coal feed can
be adjusted in response to variations in VAM
flow or concentration, allowing for a constant
energy feed to the turbine for electricity
generation. By combusting waste coal and
VAM, this technology offers the ability to
mitigate methane emissions while also
reducing acid runoff from (and spontaneous
combustion of) waste coal piles. The
technology was developed jointly by
Australia's CSIRO and Liquatech Turbine
Company Pty., and a 1.2 MW pilot plant was
constructed at CSIRO's Queensland Centre for
Advanced Technologies. EESTech Inc.
acquired the rights to the technology and is
standardizing designs for 10 MW and 30 MW
systems while actively commercializing the
technology in China and India. Because it
avoids the water requirements of steam-cycle
power generation, the hybrid coal and gas
turbine is appropriate for remote locations
where waste coal and methane are available
but water is scarce.
Although not a direct use of VAM,
advancements in concentrating or enriching
VAM to increase the methane concentration
are advancing. The Australian Coal
Association Research Program (ACARP) and
CSIRO have developed the VAMCAP™, an
enrichment technology that uses CSIRO-
developed carbon composite adsorbents to
capture and concentrate VAM into higher
concentration levels. Through the ACARP
project, the VAMCAP prototype was capable
of enriching 0.30%, 0.60% and 0.98% VAM
up to an average methane concentration of
3.49%, 6.09% and 9.46% respectively by
one-step adsorption, and up to 19.28%,
24.24% and 36.92% methane respectively by
two-step adsorption. This technology would
have significant implications for VAM use,
since there are more end-use options for
higher-concentration VAM than typical
drained gas.
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For More Information.
To obtain more information about emerging VAM mitigation technologies, contact:
Babcock & Wilcox MEGTEC (B&W
MEGTEC)
Theros Svenssons Gata 10 SE-417 55
Gothenburg, Sweden 41755
Ken Zak, Vice President
Phone: 46 (0)31 65 78 19
E-Mail: KZak@megtec.com
http://wvwv.megtec.com/
Durr
40600 Plymouth Road Plymouth, Ml
48170 USA
Jason Schroeder, Director
Phone: +1 734-254-2443
E-mail: iason.schroeder@durrusa.com
www.durr-cleantechnologv.com
www.durr.com
Gulf Coast Environmental
Systems, LLC
18150 Interstate 45 North
Willis, TX 77318
Chad Clark, Technical Director
Phone: (773) 572-5992
Email: cclark@gcesvstems.com
http://www.gcesvstems.com
Biothermica Technologies Inc.
426, rue Sherbrooke Est
Montreal, Quebec H2L 1J6
Dominique Kay, Director of R&D
Phone: (514) 488-3881
E-mail: dominiaue.kav@biothermica.com
http://www.biothermica.com/content/co
al-mine-methane
EESTech
Ground Floor, Engineering House 447
Upper Edward Street Brisbane,
Queensland, Australia 4000
Ian Hutcheson, CFO
Phone: 61-7-3832-9883
E-mail: ihutcheson@eestechinc.com
http://www.eestechinc.com/index.ph
p?page=16
HEL East Ltd.
Randall Way, Retford
Nottinghamshire, UK
Neil Butler
Design Engineer and Project
Technical Development
Phone: +44(0)1777712764
E-mail: nbutler@hel-east.com
http://www.hel-east.com/
CAN MET
1615 Lionel-Boulet Boulevard P.O. Box
4800 Varennes, Quebec, Canada
J3X IS 6
Eric Soucy, Director, Industrial Systems
Optimization Group
Phone: (450) 652-4299
E-mail: eric.soucv@nrcan.gc.ca
http://www.nrcan.gc.ca/energv/
Ener-Core, Inc.
9400 Toledo Way Irvine, CA 92618
Mark Owen, Director of Sales
Phone: (949) 616-3300
Fax: (949) 616-3399
E-Mail: info@ener-core.com
http://ener-core.com/
Johnson Matthey Process
Technologies
Paddington, 10 Eastbourne
Terrace London, W2 6LG, UK
Ian Mitchell
Phone: +44 (0)20 7957 4120
E-mail: ian.mitchell@matthev.com
http://www.improtech.com/
Commonwealth Scientific and Industrial
Research Organisation
PO Box 883 Kenmore,
Queensland, Australia 4069
Dr. Su Shi, Project Leader
Phone: 61-7-3327 4679
E-mail: shi.su@csiro.au
http://www.csiro.au
Fortman (Beijing) Clean Energy
Technology Ltd.
Steven Wan, Ph.D., CEO
E-Mail: steven@fortmanenergv.com
Contact EPA's Coalbed Methane Outreach Program for more information about this and other profitable uses for coal
mine methane:
Coalbed Methane Outreach Program Valerie Askinazi
U.S. Environmental Protection Agency Phone: + 1 (202) 564-6169
Washington, DC	E-mail: askinazi.valerie@epa.gov
Website: www.epa.gov/cmop
The mention of products or services in this case study does not constitute an endorsement by EPA.
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