Underground coal gasification. Cliff Mallett CSIRO Exploration & Mining 17 th July 2006

Transcription

1 Underground coal gasification Cliff Mallett CSIRO Exploration & Mining 17 th July

2 ENERGY SYSTEMS new options Current Current Natural Gas ELECTRICITY COAL Gasification Surface or Underground SYNGAS LIQUID FUELS CO 2 CHEMICALS

3 AGENDA History & introduction UCG How is it done? Design tools and operational control Products and gas use Environmental impacts Site selection & issues Staged Development CTL a technology for its time

4 Worldwide distribution of UCG sites

5 UNDERGROUND COAL GASIFICATION HOW IS IT DONE? A range of bore and gasification layouts have been demonstrated

6 Underground Gasification Designs Vertical Wells CRIP (Controlled Retracting Injection Point) Air Exhausted Holes Product Air/Oxygen Product 2 nd CRIP reactor 1 st CRIP reactor Steeply Dipping Bed Product Gas Air/Oxygen Tunnel Steam Air Product Flame front movement Mined tunnels

7 DESIGN & OPERATIONAL tools (CSIRO modelling) Process simulation Regional hydrology model Geotechnical model Coal model Cavity model

8 Coal Model Gas Diffusion of gases IN Char Dry coal Wet coal OUT Water flow The coal model represents lump coal reacting with a hot gas. Included in the model are: Reactions Gas diffusion Water flow Drying Heat transfer Coal structural changes Output is used in the cavity model.

9 Cavity Model concepts Coal & char reactions Coal/char structural changes Gas flow and reactions Water flows and evaporation Rock and coal breakage and collapse Resizing of the matrix with growth Heat transfer Conduction, Convection & Radiation Feed gas Drying, Volatile release & Gasification Drying & Volatile release Product gas Combustion & High temperatures Gas reduction & Moderate temperatures Drying Gas equilibrium reactions & Cooling

10 Cavity Model operation 3D model of CRIP-type reactor Injection and production points can move with cavity growth Includes chemical, heat transfer and flow processes Display accelerated for presentation purposes

11 Other models Geotechnical - COSFLOW is a CSIRO developed model for rock collapse, water flow, contaminant flow and gas flow in mining affected strata Regional hydrology MODFLOW is a public domain modelling platform for large scale hydrological simulation These and associated packages have been demonstrated by CSIRO for UCG applications in a case study analysis

12 Potential Environmental Impacts Surface subsidence Contamination Increased Permeability Water Table Water usage

13 Products and Business Opportunities The product gas can be used in wide range of fuel and synthesis applications, but we have focussed on: Power generation via gas turbine plant Synthesis of liquid fuels via Fischer- Tropsch plant

14 Process Simulation (Power Generation) GAS TURBINE GASIFY TO SYNGAS Power STEAM TURBINE Power

15 Power generation: Greenhouse emissions & Cost of Electricity Cost of electricity, $/MWh Surface Coal Gasifier IGCC with Shift & CO 2 removal from syngas UCG-IGCC with Shift & CO 2 removal from syngas TARGET OPTION UCG-IGCC with CO 2 removal from syngas Surface Coal Gasifier IGCC with CO 2 removal from syngas Surface Coal Gasifier IGCC using untreated syngas Natural Gas Combined Cycle Conventional PF Coal UCG-IGCC using untreated syngas Greenhouse emissions, tco2/mwh

16 Process Simulation (Liquid Fuel Synthesis) MAKE LIQUIDS GASIFY TO SYNGAS

17 GTL Plant (SasolChevron) Oxygen $142m Gas Treatment $7m Hydrogen Natural gas Reformer $162m CO2 Removal $34m F-T Synthesis $176m Product Work-up $47m Steam,Water & Power systems $109m Diesel 24,000bbl/d Site services $180m Gasoline 9,000bbl/day Sources: Foster Wheeler & Technip-Coflexip (Qatar plant) LPG 1,000bbl/d

18 UCG with GTL Plant Oxygen Bigger UCG Low cost Gas Treatment ~Same Hydrogen Natural gas Reformer $162m CO2 Removal Bigger F-T Synthesis ~Same Product Work-up ~Same Steam,Water & Power systems Some changes (more Power) Site services ~Same Diesel 24,000bbl/d Gasoline 9,000bbl/day LPG 1,000bbl/d

19 Site selection criteria (Ideal site) Coal seam >10 m thick Ash content <40% (ad basis) Rank not important, although low rank coals may have high moisture and high rank may be hard to ignite Well-defined seam with minimal discontinuities

20 Site selection criteria continued Seam dip <20 for most techniques or >50 for Steeply Dipping Bed Method Depth m with high hydrostatic head Overburden with low permeability/good structure No good water aquifers in vicinity Surface suitable for low impact use and some subsidence

21 Leases Overview Bowen-Sydney Basin (older) Most export quality coking coal & large amounts of thermal coal CBM exploration activity Mature exploration status Great Artesian Basin (younger) Major water, oil & gas resource Walloon thermal coal in easternmost part of basin Coal generally much poorer quality and thinner seams than in Bowen Basin

22 Leases Regional view Condamine River Area size ~ 150 x 300 km Intense agriculture over Condamine River alluvium (good aquifer) Forestry and grazing to the west Known coal deposits outline Walloon Coal Measures Coal exploration leases to the NE of selected UCG leases Natural gas, CBM & oil pipelines CBM production in NW (from Bowen Basin coal) MacIntyre River 50 KM UCG exploration leases were chosen down-dip of known coal deposits

23 Miles meters Chinchilla Leases - Walloon coal measures Austinvale (just NW of study area) Three coal seams which coalesce to form economic pods separated by areas of seam thinning (river channels?). Dalby Wilkie Creek (+ Kogan Creek etc) Four banded coal intervals ranging from 5-10m thick. Little information found to date. Moonie Onaview Economic Acland seam is a coal-rich intercal that contains 4 compound coal seams. The highest is 3-15m thick the others are 1-1.5m thick. Splitting and thick partings are common. Deposits exist underneath basalt caps. Goondiwindi Millmerran Economic Commodore seam is 5.6m thick with abundant stone bands and partings up to 0.9m thick. Deposit extent limited by modern river errosion. 40 KM [not mined in study area] Coal-free further south, sometimes mapped as Eurombah Formation

24 Surat Basin Project EXPLORE prove resource DEMONSTRATE technology POWER PROJECT demonstrate commercial scale operations COAL to LIQUID plant

25 Staged Development An initial demonstration of oxygen-blown UCG with a pilot scale CO 2 removal module and a small (~40MWe) gas turbine (which would also allow validation of liquid synthesis potential) UCG plant would be ~$15million with a 6 month commissioning operation prior to gas turbine installation With surface plant the cost will be ~$80million with the potential for significant government support plus breakeven (or better) from electricity sales Future development is likely to use the electricity plant to support expansion into chemical synthesis, such as liquid fuels, fertilisers or other chemicals

26 Global Interest in UCG Energy demand and Greenhouse Huge coal resource Extraction with low impact, high recovery Flexible easily handled gas product Costs favourable Opex V s Capex

27 Activity increasing Trials China, Australia, S.Africa UCG Partnership paying members Governments India, US, UK, Private Cos CSIRO contacts about 10 in the last 8 weeks

28 Business Opportunities Australia Xstrata, Origin Capital, Linc, AUSCID, Rio Tinto, GE Energy Aust o Own project + farm-in and technology provision to other Australian projects China Golden Gulf Canada EPCOR, Capital Resource Ptners USA Gastech/Wold Oil, Syn Tano,Chevron S Africa Anglo American Turkey Alpteks Tekstil TS India GAIL, ONGC, + many others o Partner/service in UCG supply to Coal to Liquids projects

29 The End