2. UCG PRINCIPLES & ESSENTIALS
Underground Coal Gasification (UCG) converts coal into a
gaseous form (syngas) through the same chemical reactions
that occur in surface gasifiers
The economics of UCG look promising as capital expenses
should be considerably less than surface gasification
Essentials:
Site location -biggest issue
Coal characteristics–operations
Technologies-connecting wells
3. INTRODUCTION
The technology was first widely used in the USA during the later
1800s.
Indiain Calcutta (Kolkata) and Bombay (Mumbai) in early
1900.
Lamplighters in many cities used to light streetlights by “town
gas”, the product of early and relatively crude forms of coal
gasification.
3
4. INTRODUCTION
1912 Co. Durham UK First Test
1930’s Intensive Soviet Development
1950/60’s Early European Trials – inc.
1955 Newman Spinney – Ntl Coal Board
1970/80’s US Programme - 6 Major Trials
1980’s European Studies and First Trial
Early 1990’s First US commercial designs
Mid to late 1990’s El Tremedal, Spain
European Trial
DTI UCG Initiative (1999-2005)
Australian Pilot 4
Firth of Forth Feasibility Study
5. WHY UCG NOW?
Security of supply
– indigenous coal Production Costs for clean syngas
– Un - mineable coal – Competitive against natural gas
(EU, US)
• Carbon Capture & Storage
– Pre-combustion processing Flexibility of Syngas for poly-generation
– Local storage options – Existing or new power stations, GTL,
SNG, H2 and other chemicals
Advances in UCG Technology
– Drilling, completion, control
7. CRITERIA FOR UCG
UCG requires special properties of coal seam:
Coal seam lays underground between 100 and 600 metres
(preferably more than 300 metres)
Thickness is more than 5 metres
Ash content is less than 60%
Minimal discontinuities in seam
No good water aquifers
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9. HOW DOES UCG WORK?
Step 1: Find the coal
Step 2: Drill the boreholes
Step 3: Link the boreholes
Step 4: Ignite the coal
Step 5: Inject the O2 and steam
Step 6: Extract the syngas
17. US
31 tests involving DOE, Gulf, Texas A&M, GRI,
ARCO
Rocky Mountain Trial, 14,000 tons of coal 93
days
Oxygen Fired CV 9-11 MJ/m3
Commercial scheme for ammonia production
developed – not constructed
20. ANGREN UCG POWER STATION, UZBEKISTAN
UCG
Co-fired
Plant
operating for 30
years
UCG
used in
dedicated 100MW
steam turbine
Linc
Energy have
bought a majority
stake in the plant
21. UCG IN SOUTH AFRICA
Eskom
UCG Trial at
Majuba Coal field,
3.5m thick at 300m
depth (Jan 2007).
Air-blown
co-fired
350MWe IGCC unit
planned
Sasol
initiated a new
UCG trial project at
Secunda as a potential
feedstock for CTL Plant.
22.
23. CHINA
China has over 50 large coal gasification
facilities nationwide.
China has executed at least 16 pilots since
1991,
And has invested in extensive research
programs at China University of Mining
Technology in Beijing.
24. INDIA & WORLD
There
is over 5 million PJ of resource for UCG gas
in the United States, 2.2 million PJ of UCG gas in
China, and 1.9 million PJ of UCG gas available in
India.
The
Lawrence Livermore National Laboratory
(USA)
has estimated that recoverable reserves could be
increased by at least 300% to 400% and that 1.6
trillion tons of un-mineable coal in the USA may be
recoverable with UCG.
25. AUSTRALIA
The
World Energy Council’s 2007 Survey on
Energy
Resources estimates that 45% of Australia’s
proven in place reserves, or 44 billion tonnes, is
available for extraction by UCG.
Applying
this same proportion to Queensland’s
measured plus inferred sources of thermal coal,
suggests that there are possibly 16 billion tonnes
that may be available for UCG in Queensland.
26. AUSTRALIAN DEVELOPMENTS
Linc Energy,
– Successful share offering in 2006, now
worth $1.5B
– Development of a GTL plant is underway
– New projects starting in S Australia,
Vietnam & USA (Dec 08)
Carbon Energy (2006)
– Joint venture with CSIRO gas now started
(Oct 2007)
Cougar Energy (2007)
– Site for 400MW CCGT Plant in S Australia
– Using Ergo energy.
31. OTHER FEASIBLE AREAS
Indonesia
Vietnam
Pakistan
(Thar Coalfield
Power & GTL)
Japan
Chinese Mining Companies,
e.g. Xinwen, Ezhuang
Mongolia
New Zealand (Solid Energy)
32. INDIA
GAIL also plans to set up a coal gasification
project in eastern India (Durgapur, Haldia, and
Talcher) to produce 3.4 MSCMD of syngas.
In September 2005, GAIL has signed an
memorandum with the Shaanxi Huashan
Chemical Industry group of China to undertake
coal gasification activities in the Shaanxi
province.
33.
34. INDIA
GAIL
(India) Ltd has signed a memorandum of
cooperation with Ergo Exergy Technologies Inc.,
Canada, to explore UCG projects in India.
Ergo
Exergy will help GAIL to
i) determine the technical and economic viability
of each project
ii) bring in efficient drilling techniques and
production of UCG gas in commercial quantity with
quality.
36. UCG IN INDIA
The
Neyveli Lignite Corporation Ltd. (NLC), which has
got Government approval for taking-up a UCG Project
in lignite deposits of Rajasthan, has not been able to
get a suitable technical partner, so far.
• The Reliance Industries Limited (RIL) has been
exploring possibilities for taking up a UCG project in
India.
37. UCG IN INDIA
ONGC,
while drilling in search of hydrocarbons,
discovered large reserves of coal at depths more than
600m.
These
are spread in Gujarat and West Bengal and
have been estimated to contain more than 350bt of
coal deposit.
In
Gujarat alone, these coal reserves have been
estimated to be around 63 bt in Mehsana-Ahmedabad
block and 60 bt in Patan-Tharad block.
38. UCG IN INDIA
The
energy estimated for Mehsana - Ahmedabad
block alone, is equivalent to about 15,000 bcm of
natural gas.
The
ONGC is conducting a pilot test in Mehsana area
at an estimated cost of Rs 9.60 crores.
• An Information Well – UCG-1 – was drilled in 1986 to
a depth of 1005m at the selected site.
41. POSITIVE FACTORS
1. UCG is the only feasible technology, which enables
exploitation of deep (> 700m) coal reserves, which
are not amenable to known conventional mining
methods.
2. UCG offers an environmentally clean way to harness
energy from coal.
3. UCG brings no solid waste to the surface.
42. POSITIVE FACTORS
4. Even at shallower depths (< 500m), UCG can be more
economical than conventional mining.
5. UCG reduces capital investment, operating costs, and
the output gases cost by 25 to 50% as compared to
surface gasification.
6. Possibilities of transport of medium calorific value gas
over a distance of 100 km. exist.
43. POSITIVE FACTORS
7. Possibilities of using CO2 from the gas for enhanced
oil recovery exist.
8. Basic UCG technology is known.
9. Conditions in India are far more compelling for
adopting UCG than most locations in the world.
44. ANNUAL CASH FLOW FOR 1,000MW UCG GAS PLANT WITH
CO2
CAPTURE (CO2 $20/TONNE)
Internal
rate of return
25-30%, (with storage)
CO2credit 32% of
revenue
Syngas Utilisation
Options
480 Mwe electrical
power
10,00 bb/d diesel
savings
45. ADVANTAGES:
Much
higher coal extraction – up to 95%
No pillars
Multiple seams
Thick and thin seams
More economic – less capital expenditure
Economic on a smaller scale
Potential to be cleaner technology – smaller
environmental footprint
Little or no rehabilitation required
No fine coal
No Ash
Safer
47. CONCLUSION
Viable alternative mining method for otherwise
unminable coal
Potential smaller environmental footprint than
conventional process
Better utilisation of coal reserves
