1. BEST PRACTICE IN VAM PROCESSING What is VAM? Why is VAM an issue?
Ranchi 9-10 March 2017
Richard Mattus
What is VAM?
Why is VAM an issue?
Why is VAM a ”climate opportunity”?
Technologies for processing VAM
Proven technologies so far
Successful installations
Guide lines for feasibility

2. COAL MINING, METHANE and VAM
When coal is formed, so is methane.
When coal is excavated, methane is released
Methane in air is explosive at 5 – 15 %
Methane is drained prior to and after excavation
Heavy ventilation to dilute emitted CH4: Concentrations typically below 1 %
Good margin to 5%, so safety problem solved!
.. very large flows of ventilation air means very large CH4 emissions ..
.. which has turned out to be a powerful GreenHouse Gas.

3. VAM is a major single source of emissions.
VAM GreenHouse EFFECT on global warming
1 million t CO2e
VAM is a major single source of emissions.
½ million cars =
Coal fired
Power plant
300 MWth =
Coal mine VAM
m3/h, 0.8%
( t CH4/yr)
1 million cows =

4. One thin bubble of atmosphere
Atmosphere thickness to the Earth is
like the skin to the apple

5. One thin bubble of atmosphere
Increase of CO2 content increases average atmospheric temperature.

6. One thin bubble of atmosphere

7. CO2 in atmosphere can retain a bit of the sun’s heat.

8. Methane can retain a lot!

9. Global Methane Emissions - by source
(ANTHROPOGENIC)
CO2
CH4
Global Warming Power 1
25*
Life time in atmosphere (years) –
50 000 12
Source: GHG emissions 2012, IEA, International Energy Agency
* Based on 100 yrs comparison
Second most important greenhouse gas
Much more powerful greenhouse gas than CO2
Short life time in atmosphere, so emission reductions will have a quick, positive impact
Generates energy when abated (oxidized)

10. Global Warming Potential – CH4 vs CO2
Methane is a very powerful GHG. Especially short term!
100 years
20 years
CO2
CH4
12 years 12
years 20 20
Acc to IPCC (5th Assessment Report, 2014):
Compared on 100 yr basis; Methane 25 times more powerful
Compared on 20 yr basis; Methane 72 times more powerful

11. Impact of major emission reduction – CH4 vs CO2
Reducing VAM emissions quickly has a powerful positive impact.
Fossile
Power
Plant
Coal mine
Vent
Shaft GW
impact
Time
CO2
CH4
Major emission reduction
(by for example 90%)
12 yrs

12. TECHNOLOGIES FOR PROCESSING VAM
CONDITIONS:
Very large volumes of air with extremely low CH4 content.
~ Nm3/hr <1% to <<1%
TECHNOLOGY
SPECIFICS
ISSUES
COMMENTS
COMBUSTION AIR with
VAM as supplementary fuel
For power plants, (turbines, boilers)
Very large air volumes.
Hard to find large user nearby a ventilation shaft.
LEAN GAS TURBINES
Have managed to come down to 2-3%.
Typically combined with drainage gas. Very large air volumes.
So far only lab scale installations reported.
CONCENTRATORS
Increase CH4 concentration.
Technical difficulties. Very large air volumes.
No successful installations or trials officially reported yet.
RTO, Regenerative Thermal Oxidizers
Need only 0.2% CH4 for self sustaining oxidation process.
No major issues for experienced suppliers.
Proven technology for VAM with several long time installations.
RCO, Regenerative Catalytic Oxidizers
Catalyst lowers the temp needed for oxidation.
Catalyst can be “poisoned” by e.g. S. Catalyst needs at some point to be exchanged.
Several RCO solutions in trial. No success officially reported yet.
Recuperative Thermal Oxidation
Passes pollutant (CH4) by an open flame.
Most traditional industrial oxidizer. Very costly to operate.
No serious attempts due to low financial feasibility.
INDUSTRIAL OXIDIZERS

13. VAM PROCESSING AND CARBON CREDITS
1997 Kyoto Conference
- Agreement to reduce emissions and to introduce mechanism of Carbon Credits
2009 Copenhagen Conference
Failure to extend Kyoto Protocole
1992 Rio Conference
- Agreement to establish the UN Framework Convention on Climate Change, UNFCCC
Official launch of Kyoto related Carbon Credits
2015
Paris
Agreement
CARBON CREDITS TRADING
VARIOUS ETS (Emission Trading Schemes)
EU ETS
CARBON CREDITS TRADED
2015
2017
2012
2007
2009
2001
1997
1994
1992
LARGE SIZE VAM
Power plant,
GaoHe China
LARGE SIZE VAM INSTALLATION
Power plant, WestVAMP, Australia
Abatement, hot water, SongZao, China
UK trial at
British Coal
A few months
Australian trial
at BHP
A full year
Abatement demo 1½ year
CONSOL, US
VAM PILOT
Abatement, McElroy, US
Abatement/hot water, China
Abatement, JWR, US
VAM PROCESSING

14. COMMERCIAL SIZE VAM PROCESSING
DaTong Nm3/h
ZhengZhou
Nm3/h
CONSOL Energy
Nm3/h
McElroy,
Nm3/h
VAM Power Plant GaoHe
Nm3/h
VAM Power Plant WestVAMP
Nm3/h
JWR
Nm3/h

15. COMMERCIAL SIZE VAM PROCESSING
IN OPERATION BY 2017
McElroy,
Nm3/h
Since 2012
VAM Power Plant GaoHe
Nm3/h
Since 2015
Closures due to :
Moving of mining activities
Failing values of carbon credits

16. RTO technology
- How does it work?

17. Energy Principle of RTO reaction Reaction Temperature
Like all VOC gases,
methane oxidize at oC
to form water and CO2.
And release Energy!

18. VOC Oxidation Rate
100%
Oxidation Rate
1000 °C
Temperature

19. Single can RTO No catalyst operate at natural oxidizing temperature
RTO FUNCTION:
Heat center cross section of ceramic bed to 1000oC.
Pass ventilation air through, heating media, oxidizing all VAM in air passing the hot zone.
Change direction of flow, making hot zone remain in center bed section.
20oC
1000oC
60oC
No catalyst
operate at natural oxidizing temperature

20. Single can RTO
Flow down
Flow up

21. Oxidation in a combustion chamber instead of in the ceramic bed.
2 Can (or more) RTO
Main difference between the single can RTO and 2 can or multiple can RTO’s:
Oxidation in a combustion chamber instead of in the ceramic bed.

22. RTO installations typically consists
of multiple modular RTO units.

23. PURE VAM ABATEMENT Min 0.2% CH4 to keep oxidizing going .
If higher, the excess can be utilized..

24. CONVERTING ENERGY OF VAM INTO USEFUL ENERGY
Min 0.2% CH4 to keep oxidizing going .
If higher, the excess can be utilized as
Heating/cooling or as electricity.

25. Indications of VAM project economics
GUIDE LINES
The project economics of a VAM processing installation will largely depend on;
Total costs for investment, operation and maintenance.
Average VAM concentration of the ventilation air being processed.
The value of reducing the emissions.

26. VAM Energy Recovery with RTO’s as boiler units
GUIDE LINES
VAM Energy Recovery with RTO’s as boiler units
0.2 % methane needed to maintain oxidation.
Energy of concentrations above 0.2 % can be recovered.
Example: m3/h
72 MW(th) MW(el)
1 % CH4 (at 30% efficiency)
Example: m3/h
36 MW(th) MW(el)
0.6 % CH4 (at 30% efficiency)

27. Cogeneration of electricity and heating – plus cooling
GUIDE LINES
Cogeneration of electricity and heating – plus cooling ~
Cooling water from electricity generation
drives absorption chiller
Example:
m3/h
1% methane 72 MW(th) 21 MW(el) 19 MW(el) + 38 MW(cool)

28. Hot water from VAM (thermal energy)
GUIDE LINES
0.3%
0.6%
0.9%
Heat straight from bed.
Water at oC
3 MW
11 MW
18 MW
- - For each Nm3/h of ventilation air
Secondary heat-exchanger.
Water at 70oC
1 MW
8 MW
15 MW
Water at 150oC -
2 MW
10 MW
Heat
Exchanger

29. Electricity from VAM (electrical energy)
GUIDE LINES
0.3%
0.6%
0.9%
Heat straight from bed.
Water at oC
3 MWth =
½ -1 MWe
11 MWth
3 -4 MWe
18 MWth
5 - 6 MWe
- - For each Nm3/h of ventilation air
For large size plants, conversion from thermal to electrical energy can be expected to be around 30%, and lower for smaller plants.

30. Calculations of CO2e from VAM processing
GUIDE LINES
Examples:
250  % VAM comes to 240 000 tonnes of CO2e
125 000 0,9 % VAM comes to 120 000 t CO2e
125 000 0,3 % VAM comes to   40 000 t CO2e
VAM conc’n
Nm3/h vent air
0.3 %
0.6 %
0.9 % 40 80
120
160
240
320
480
640
960
Annual emission reductions in thousand tons of CO2e

31. VAM project economics indications
GUIDE LINES
VAM project economics indications
CONCLUSIONS for reasonable/good pay back:
VAM concentrations should be min ½ percent
Carbon Credits should be minimum EUR 10/t CO2e

32. Overall OPTIMIZATION of CH4 - CMM and VAM emissions
Very high
volumes.
Very low
concen-trations.
Low CH4
< 1%
High CH4
>30%
High CH4
Main
Coal
Mine
Vent
Shaft
Coal Excavation

33. Overall OPTIMIZATION of CH4 - CMM and VAM emissions
For optimization if motivated by VAM energy utilization.
Low CH4
< 1%
Gas Engines
High CH4
>30%
VAM
processing
Main
Coal
Mine
Vent
Shaft
Coal Excavation

34. CONCLUSIONS CH4 & VAM and CARBON CREDITS(Climate Change perspective)
CH4 is a very powerful GHG, especially short term
Short atmospheric life time of CH4 means quick, positive effect on climate change
VAM represents a major single emission source of GHG
VAM PROCESSING
Experienced RTO suppliers can provide proven VAM processing solutions
There will be more suppliers and more technical solutions to VAM processing
For best feasibility of VAM projekts, look for:
VAM concentrations of ~½ % or more
Possibility to enrich the ventilation air (into VAM processing) to min ½%
Possibilities to utilize thermal energy close to ventilation shaft (cooling?)
Look for good value of reducing VAM emissions (Carbon Credits or similar)
Optimize your overall emission strategy between processing of drainage gas and VAM