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Challenges in implementation of Underground Coal Gasification
Project
The Presentation
Energy Scenario and UCG
UCG – A Brief
ONGC’s Experience
Learnings
Sum up
India… 16% of Global population
0.5% of world’s petroleum reserves
7.1% of coal reserves
Targeting 8-9% GDP Growth, the CAGR in primary energy demand works out to 4.5%
India faces a formidable challenge on Energy front
INDIA….
Has the 4th largest coal reserves in the world (264 Billion Tons)
Ranks 3rd in coal production (492.95 Million TPA)
Total Recoverable reserves are only about 20%
Underground Coal Gasification is the only way to harness these unrecoverable reserves
The Presentation
Energy Scenario and UCG
UCG – A Brief
ONGC’s Experience
Learnings
Sum up
What is Underground Coal Gasification?
UCG Process
Drilling of adjacent bore holes in the coal seam and its linkage
Down hole ignition of the coal seam
Injection of a pressurised oxidant such as air/oxygen and steam
Removal of product gas to surface.
Underground coal gasification (UCG) Converts coal / lignite in-situ into a gaseous product, commonly known as synthesis gas or syngas.
Sounce: http://www.ausairpower.net/APA-USAF-SynFuels.html
Carbon/coal gasification reactions
Partial Combustion C + O2 = 2CO exothermic
Combustion C + O2 = CO2 exothermic
C + CO2 = 2CO endothermic
Water-Gas C + H2O = CO + H2 endothermic
Hydrogasification C + 2H2 = CH4 exothermic
Shift CO + H2O = CO2 + H2 exothermic
Reformation CO + 3H2 = CH4 + H2O exothermic
AIR
CO2 %, 19.35
CH4 %, 2.26
CO %, 7.48
H2 %, 14.63
N2 %, 56.16
H2S %, 0.1
Cal. Value : 3.43 MJ/M3
AIR ENRICHED WITH 50% O2
CO2 %, 26.8
CH4 %, 3.4
H2S %, 0.2N2 %,
19.7
H2 %, 34.1
CO %, 15.7
Cal. Value : 6.77 MJ/M3
AIR ENRICHED WITH 65% O2
CO2 %, 27.9
CH4 %, 3.6
CO %, 16.3
H2S %, 0.2N2 %,
16.5
H2 %, 35.5
Cal. Value : 7.34 MJ/M3
AIR ENRICHED WITH 95% O2
CO2 %, 29.9
CH4 %, 3.9
H2S %, 0.2
CO %, 19
N2 %, 4.1
H2 %, 42.8
Cal. Value : 8.93 MJ/M3
Composition of typical dry UCG product gas with increase of O 2 enriched Air
SYN GAS
Power
Nitrogenous Fertilizers
Petrochemicals
Liquid Fuels
Product usage….
Underground Coal GasificationUnderground Coal Gasification
Technology plays an important role UCG process
Well configuration and well spacing
Different types of wells such as vertical, inclined or horizontal, with intersections
Wells to be completed properly with special high temp. resistant cements, tubular and well heads
Injectors & producers need to connected and gasification passage Flame treated
Compression and injection of the air & steam through the set of injector wells for maintaining gasification
Producing, cooling and processing of the produced gas
The Presentation
Energy Scenario and UCG
UCG – A Brief
ONGC’s Experience
Learnings
Sum up
UCG Pilot Flow Diagram
Detailed Exploration
Site selection
Pilot Design
MiningLease
LandAcquisition
Drilling of wells
Commissioning of Surface Facilities
Linkage of Wells,Flame Treatment
Trial Run of UCG Pilot
Environmental Clearance
Fabrication, Erection of Surface Facilities
13
1st stage : Site Selection
ONGC working with Russian scientists to test UCG technology
MoUs also signed with coal companies
Fifteen sites studied – Five sites found suitable for UCG
One site in South Gujarat, prioritized for UCG pilot study
The site is adjacent to the pit head Power Plant
DETAILS OF UCG BLOCK
2nd stage : Detailed geological and Hydro geological studies
More than 20 boreholes drilled
Detailed Geological and Geo-mechanical studies carried out
Hydrological & Hydrodynamic studies carried out
HRSS carried out
250X250-Line Interval
Lines Covered (FS 06-07)
Well for loggingDrilled Bore wells
Lines Covered (FS 07-08)
L1L2
L3L4 L5
L6L7L8
L9L10
L11L12
L13L14
L15L16
L17L18
L19L20L21
L22L23
L24L25
L26L27L28L29
L30L31
Seismic Grid
Structure Contour Map of Seam1 (based on 2D HRSS)
V 7
F
F
F
F
V-07
V-07
Based on bore well data Based on HRSS data
Lin
e-1
Lin
e-2
Lin
e-3
Lin
e-4
Lin
e-5
Lin
e-6
Lin
e-7
Lin
e-8
Lin
e-9
Line-
1L
ine-
2L
ine-
3L
ine-
4L
ine-
5L
ine-
6L
ine-
7L
ine-
8L
ine-
9
Line-32
Line-10
Line-11
Line-12
Line-13
Line-14
Line-15
Line-16
Line-17
Line-18
Line-19
Line-20
Line-21
Line-22
Line-23
Line-24
Line-25
Line-26
Line-27
Line-28
Line-29
Line-30
Line-31
Line-31Line-30Line-29Line-28Line-27Line-26Line-25Line-24Line-23Line-22Line-21Line-20Line-19Line-18Line-17Line-16
Line-15Line-14Line-13Line-12Line-11Line-10Line-32
Based on Seismic data
V-07
Structure contour map
3rd stage : Pilot Design
Pilot lay out firmed up
Detailed Engineering Design is available
The Commercial UCG Station Well Pattern…..
The Presentation
Energy Scenario and UCG
UCG – A Brief
ONGC’s Experience
Learnings
Sum up
UCG is a site specific technology
Data required for proper site selection is not usually available with the mining companies
Large amount of data like the hydro-geological data, seismic data, geo-mechanical data etc. has to be generated
All these data generation can tend to delay the time schedule of the project, if not accounted for properly
Site Selection Drilling of
Boreholes
Geophysical Logging
Hydro-geological
studies
Seismic Survey
•Geo-chemical Studies •Petro-physical Studies•Geo-mechanical Studies•Maceral Studies
Sample collection &Lab Studies
Flow Diagram for Site Selection
Compilation and Analysis of
existing data
Detail Field Investigation
Topographical data
Geological Data
Hydrological Data
• Hydro-dynamicparameters
• Chemical composition
• Precise Fault mapping• Continuity of
coal/ lignite beds
Boreholes
Geophysical Logging
Seismic Information
23
FF
FF
FF
FF
V-07V-07
V-07V-07
Use of seismic as an exploratory tool vis – a vis borehole drilling
Based on borehole data Based on HRSS data
UCG process is technology dependent
Process wells in a UCG panel involves a combination of vertical and horizontal wells which need to intersect to make a gasification passage
High degree of accuracy Drilling challenge to drill horizontal
sections of more than 100 meters through coal / lignite at shallow depth
Producers and injectors need to be interlinked and flame treated
Syngas that is produced is at a high temperature of around 2000 C and needs to be cooled down before processing
The clean up process will change with the end usage and is not similar to the one for conventional HC gas
Project is technologically dependent - ready on the shelf solutions are not available
Claimed to be available with only selected few
UCG & Economics
No authentic publication of figures in literature for carrying out cost economics
Sale of Syngas considered on energy basis (rate / BTU) will give the project a technological disadvantage
Costing of a UCG Project and economic calculations thereof are a challenge
A pilot must be considered as an R&D investment to boost the development of UCG in India
Regulations
Gazette notification Issued in July 2007 UCG can be end uses for the act
Guidelines for UCG Issued in July 2009 Provision for nomination of coal blocks to
National coal companies The applicant company should have minimum
net worth of Rs. 200 crores The applicant company should have
collaboration /tie up with the proven technology providers
The normative time limit Explored Blocks - 36 months Unexplored Blocks -24 months +36 months
Penalty for slippage in meeting time limit
Flow diagram of UCG Commercial Plant
Site Selection
Demo Plantof
End Usage
Post Pilot Monitoring
UCG Pilot
Detailed Characterization
CommercialUCG Station
Start
UCG is site specific technology It requires pilot testing before commercialisation
Linc Energy – Chinchila Pilot(1999 - 2003)Restarted Commercial operations in 2007 and reached up to Demo in 2009
A demo plant has to be consideredbefore commercialisation
Govt. coal companies given preference forNomination of Blocks
The Presentation
Energy Scenario and UCG
UCG – A Brief
ONGC’s Experience
Learnings
Sum up
The energy requirements of India are expected to grow by CAGR of 4%. Coal will continue to occupy centre-stage of India's energy scenario
UCG is the only feasible technology to harness energy from deep unmineable coal seams, in an economically and environmentally clean way
ONGC has embarked on a highly prestigious project of UCG and is poised to demonstrate the UCG technology in the near future
Summing up
Cont… The complexity of UCG makes it technologically
dependent where still ready on the shelf solutions are not available. The technology required for drilling, linkage, flame treatment and hot gas clean up is claimed to be available with only selected few
Costing of a UCG Project and economic calculations thereof are a challenge
The present statutory regulations require further refinement
Recommendations Preference for award of coal blocks should also be
given to other coal companies who can demonstrate the technology early
Provision of a pilot and a demo plant has to be made in a UCG Project, which if successful should be followed by a commercial venture. This will necessitate increasing the normative time for commercialization of UCG in the guidelines
Since UCG is a complex underground process, which is yet to be commercialised in India, it requires support of GoI in the form of relaxation in policies and a lucrative economic package. This will help in faster development of UCG Technology in India
Geological Section of Vastan (Dip)
DD:249.7
DD:342
DD:280.5
DD : 249.7 m
DD : 342.0m
DD : 280.5 m
V-1V-13V-7 NW
SE
ALLUVIUM/VAR.CLAY
LIMESTONE
FOSSILIFEROUS CLAY
CLAYSTONE
LIGNITE
FAULT
LEGEND
CH424%
C0231%
C018%
H227%
Composition of typical dry UCG product gas
(Calorific Value 13.6MJ/Nm3)(Calorific Value 13.6MJ/Nm3)
(Spanish Trial-Gasification with Oxygen)
N251%
CH41%
H222%
CO219%
H2S0%
CO7%
(Angrenskaya – Gasification with Air Injection)
(Calorific Value 3.5 MJ/Nm3)(Calorific Value 3.5 MJ/Nm3)
Product Gas Composition
Composition Wet Gas, % Wt Dry Gas, % Wt
CO2 13.83 19.37
CH4 1.38 1.94
CO 5.34 7.48
H2S 0.08 0.10
H2 10.45 14.63
N2 40.11 56.16
H2O 28.58 0
C2H4 0.23 0.2
O2 0 0
Flow sheet of gasifier, UCG pilot
Earlier Field Trials
UCG has been tested in many different experimental tests in many countries.
The Former Soviet Union executed over 50 years of research on UCG, field tests and several commercial projects, including an electric power plant in Angren, Uzbekistan that is still in operation today after 47 years.
The U.S. carried out over 30 pilots between 1975 and 1996, testing bituminous, sub-bituminous, and lignite coals.
Since 1991,China has executed at least 16 tests, and has several commercial UCG projects for chemical and fertilizer feedstocks.
In 2000, Australia began a large pilot (Chinchilla) which produced syngas for 3 years before a controlled shut-down and controlled restart.
At present, multiple commercial projects are in various stages of development in the U.S., Canada, South Africa, India, Australia, New Zealand and China to produce power, liquid fuels, and synthetic natural gas.
Development of a Generalized Simulation Model
Factors to be considered
Drying of porous media Devolatilisation or pyrolysis of coal Gasification reactions of char with oxygen, carbon dioxide,
steam and hydrogen Gas phase reactions – combustion, water-gas shift and
methanation Gas flow – turbulent and laminar Heat transfer – conduction, convection and radiation Water flow through porous media Physical and thermal degradation of solids Site layout and geophysics
Downstream Application of the Syngas:
Dimethyl Ether (DME) can be used : For Power Generation, As LPG Substitute, As
Transportation fuel, As Chemical feedstock etc. Methanol to Olefins (MTO)
Coal gasification route can be extended to manufacturing olefins
from methanol (called MTO). Coal to Liquid Petroleum (CTL) The project involves direct conversion of coal to syngas,
from which hydrogen will be separated to be further processed along with coal to produce liquid hydrocarbon (Fischer Tropsch process). This liquid hydrocarbon will be refined / distilled like in a typical refinery to produce gasoline and diesel, naphtha etc. Waxes are the byproduct of this process.
Downstream Application of the Syngas:
Ammonia / Urea N2+3H2 2NH3 2NH3 + CO2 CO(NH2)2 +H2O Methanol for Gasoline Blending
CO + 2H2 CH3OH
Dimethyl Ether (DME) MeOH Synthesis CO + H2 CH3OH
MeOH Dehydration2CH3OH CH3OCH3 + H2O
Water Gas ShiftH2O + CO H2 + CO2 Net Reaction: 3H2 + 3CO CH3OCH3 + CO2
Process efficiencies
Process EfficiencyIGCC ~45.0%
Conventional coal ~37.0 %
UCG-CO2 separation
39.8 %
Oxygen UCG 46.5 %
Air UCG 45.4 %
•Efficiency of processes for electricity production
• The gasification occurs within a bubble in an aquifer the gas pressure inside the bubble prevents the water from quenching the
reactions.
• Due to the elevated temperature of the gas, water evaporates into the bubble and it is only the flow of water through the surrounding solids that prevents the gas bubble from expanding excessively, a situation that can lead to loss of gas into the surrounding strata.
• The location and size of the bubble will depend on factors such as
the gas pressure, temperature and water inflow rates.
• Release of volatiles from the coal is likely to cause hot regions due to combustion of the volatiles, causing localized drying. Conversely, in cold regions it is likely that water will seep into the void and
reactions will be extinguished.
Concept of UCG Process
•While char combustion is possible in the void, it is unlikely that it will be sustained due to all oxygen being consumed before it can contact the char surfaces.
• Most char will be consumed by steam and carbon dioxide gasification reactions, with steam dominating due to the high moisture levels.
• As these reactions are endothermic, they require that the char must be kept hot for reaction rate to be maintained. This requires locally high gas temperatures and heat transfer through radiative or convective means,
• The driving force for a sustainable UCG process will be the combustion of volatiles and gasification product gases by the injected oxygen.
Concept of UCG Process
Shift conversion:
CO + H2O CO2 + H2 + 42.3 KJ/ Kmole The rxn is used to adjust H2/ CO ratio in the feed gas for methanation/ hydrogenation rxns. Also used in reforming rxn of CH4. and NH3 production.
Methanation/ Hydrogenation reactions:
is used to produce additional CH4 from H2 and the oxides of carbon in case of SNG production.
CO + H2 CH4 + H2O
Steam reforming:
CH4 + H2O CO + H2- 206 KJ/ Kmole
CH4 + 2 H2O CO2 + H2- 167 KJ/ mole
The CH4 is reformed under specific CO/ H2 ratio thru shift conversion of CO
Potential of UCG Syngas ~64.17 TCM
What UCG can offer for India …
303 Billion Tons (Coal+Lignite Reserves)
47 Billion Tons
(Minable Reserves)
256 Billion Tons
(Unminable Reserves)
25.7 Billion Tons
(Reserves amenable to UCG)
India’s Energy Mix (Requirement)
Total 306 kgoe Total 1125 kgoe
Source: Integrated Energy Policy, Govt. of India, Planning commission, New Delhi
2004 % Share of Commercial Primary Energy
Resources
Nuclear1.5%
Hydro 2.1%
Coal51.3%
Oil36.3%
Natural Gas8.8%
2032 % Share of Commercial Primary Energy
Resources
Natural Gas11.9%
Oil29.4%
Coal50.6%
Hydro 2.1%
Nuclear5.9%
Oil consumption to grow by CAGR 4.0%
Gas consumption to grow by CAGR 6.1%
Underground Coal GasificationUnderground coal gasification (UCG) is the in-situ conversion of coal into combustible gases (CO, H2 & CH4)
•A complex process involving•chemical reactions •heat and mass transfer•complex flow dynamics &•growing cavity dimensions.
•Advantages over conventional process are•Low dust and noise•No ash handling at power stations•No coal stocking and transportation•Larger coal resource exploitation•Converts sulphur (S) to H2S and nitrogen (N) to NH3 instead of SO2 and Nox
•Disadvantages–Surface subsidence–Aquifer water contamination
Revival of Interest in UCG
Early part of last century -there was lot of interest in UCG especially in erstwhile USSR
Subsequently, huge natural gas reserves were discovered in Russia-interest in UCG died out
Surge in demand for energy as well as prices of crude oil has renewed interest in UCG all over the world
Recently, Australia and South Africa have carried successful tests. In China and other parts of the world several projects are planned/ being carried out
49
ONGC an Indian State Enterprise…
and an integrated Oil & Gas Corporate
with interests in E&P, Refining, LNG, Power, Petrochemicals & New sources of energy
… a reliable energy solution provider for the country
In pursuit of new Energy Sources
CBM: Coal Bed MethaneUCG: Underground Coal Gasification
Synergies between Oil & Gas and UCG
Drilling
Oil and Gas Oil and Gas ExplorationExploration
andand ProductionProduction
UndergrounUnderground coal d coal
GasificationGasification
Intelligent well completions
Coiled-tubing techniquesOil & Natural gasProcessing
In-situ combustion
Pneumatic fracturing techniques
Compression & transportation of Natural gas
Exploration
Commercial UCG Station
V-7
V-1
V-13
V-8
V-14
V-2
V-3
V-4
V-5
V-6
V-15
V-16
V-17
V-18
V-9
V-10
V-11
V-12
Plan to produce Plan to produce 2 BCM Syngas from2 BCM Syngas fromtwo gasifiers per yeartwo gasifiers per year
Suggestions
Inclusion of Pilot and demo plant to be considered in the overall scheme thereby increase in time limit for commercialisation
Preference for award of coal blocks be given to companies who can demonstrate the technology early
Lucrative economic package by the GoI will help faster development of UCG Technology in India
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