UNDERGROUND COAL GASIFICATION. By Lian Hattingh

Transcription

1 UNDERGROUND COAL GASIFICATION By Lian Hattingh

2 Agenda What is UCG The history of UCG How does UCG work Environmental impact of UCG Why Sasol is interested The impact of UCG on Sasol business Advantages/Disadvantages of UCG Conclusion

3 What is Underground Coal Gasification Gasification of coal in the seam using air or oxygen injected down a borehole product gas is extracted UCG uses similar process to surface gasification except, the reactor is underground, in the coal seam Can be utilized on resources which are not otherwise feasible or economic to mine

4 History of UCG UCG is not a novel technology Been tested and investigated in: China Europe Australia, NZ Russia USA SA China, Russia, Australia, NZ, SA drive UCG on a commercial scale

5 UCG Research in Different Countries Russia First research into UCG in 1930 s Commercial scale from 1945 Conducted extensive research into UCG Developed linked vertical well technology Conduct UCG at depths < 200m Mostly used for electricity generation and industrial use Ran 12 commercial sites

6 UCG Research in Different Countries Europe Started research in 1950 s Have run 15 pilot sites More research for coal at greater depths Currently - UCG under North Sea USA Main focus on shallow relatively thick seams Research into steeply dipping seams Conducted 50 pilot projects 2 incidents of significant ground water contamination Poor site selection Incorrect cavity pressure

7 UCG Research in Different Countries China UCG employed in existing coal workings Developed long tunnel method for pillar extraction Drive UCG on a very big scale Australia Ran tests using linked vertical well technology Currently developing commercial scale project - can produce 5 barrels/day size of project will increase gradually

8 Chinchilla Coal to Liquids (CTL) Demo Plant Australia Anonymous. Emerald Coal Drilling to Commence and Chinchilla Demo Plant Update. 2008

9 UCG Research in Different Countries Uzbekistan USA Photos adapted from: and

10 UCG Research in Different Countries Australia Europe (Spain) Photos adapted from: Originally - Blinderman & Jones, 2002 Gasification Technologies Conference but also from and

11 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 O 2 and steam Step 6: Extract the syngas

12 How Does UCG Work

13 How Does UCG Work Dr. Micheal Blinderman. Linc Energy. UCG. (25 June, 2008)

14 How Does UCG Work Dr. Micheal Blinderman. Linc Energy. UCG. (25 June, 2008)

15 How Does UCG Work Dr. Micheal Blinderman. Linc Energy. UCG. (25 June, 2008)

16 How Does UCG Work Dr. Micheal Blinderman. Linc Energy. UCG. (25 June, 2008)

17 Reactor Cavity Feed: O2/Steam Or Air P H Underground: Coal Water Underground: Coal Water Graphic adapted from the internet

18 How Does UCG Work Anonymous. World Coal Institute. Underground Coal Gasification. (25 June, 2008)

19 How Does UCG Work Graphics adapted from publications available on the internet

20 Environmental Impact Ground water contamination is preventable UCG leaves environment largely untouched Piping is removed and boreholes are cut off and filled Only trace elements of contaminants are left underground Air is used only once, instead of using air for mining ventilation and again for gasification In comparison to conventional CTL process

21 Why Sasol is Interested Provides opportunity for growth Escalating oil prices Growing costs of setting up the CTL process Ability to liberate unminable coal Alternative mining method for geologically unstable areas

22 Reasons For Piloting at Secunda Site The following must still be determined Gas compositions Advancement of reactor O 2 & H 2 O feed into reactor Hydrostatic pressure drop as water is used Water influx rate into reactor (function of reactor size)

23 Impact of UCG on Sasol Business The UCG Pilot will investigate the feasibility and commercial viability of UCG in the CTL process Interest in the production of synthesis gas in the most efficient way Gasify unminable coal and test gas quality and quantity

24 Advantages / Disadvantages of UCG 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

25 Advantages / Disadvantages of UCG Disadvantages: Potential for contamination More pressure variations within reactor cavity

26 Conclusion Viable alternative mining method for otherwise unminable coal Pilot projects and research are underway in SA Potential smaller environmental footprint than conventional CTL process Better utilisation of coal reserves

27 Questions? Questions can be directed to Johan Brand the UCG project leader at Sasol at

28 References Anonymous. Ergo Exergy. Welcome to underground coal gasification. (25 June, 2008) Anonymous. Wikipedia, the Free Encyclopedia. Underground Coal Gasification. (25 June, 2008) Anonymous. World Coal Institute. Underground Coal Gasification. (25 June, 2008) Dr. Micheal Blinderman. Linc Energy. UCG. (25 June, 2008) Anonymous. Linc Energy. (25 June, 2008) Anonymous. Emerald Coal Drilling to Commence and Chinchilla Demo Plant Update Brand, Johan. UCG History Presentation Brand, Johan. 2008, pers.comm., 23 June & 30 June Van Vuuren, Peter. 2008, pers.comm., 20 June