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Disclaimer I am not an expert in UCG

Disclaimer I am not an expert in UCG Talk uses public sources with added interpretation/opinion by author Contains more detail than can be covered here May be useful later A lot of “ Average ” numbers used in calculations Results only indicative at best Use with extreme caution

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Disclaimer I am not an expert in UCG

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  1. Disclaimer I am not an expert in UCG Talk uses public sources with added interpretation/opinion by author Contains more detail than can be covered here May be useful later A lot of “Average” numbers used in calculations Results only indicative at best Use with extreme caution Listener beware Be critical

  2. Introduction to UCG Some generalities

  3. What is Underground Coal Gasification UCG Burn coal insitu and recover a low btu gas at surface link air injection hole and gas recovery hole Burn can move towards air injection hole (counter current circulation ) or in same direction as air towards gas recovery hole (co current circulation) Coal seam Courtesy ErgoExergy

  4. Putting UCG in perspective Coal gasification and liquefaction at surface are commercial processes around the world Over 30% of petroleum used in South Africa is produced from coal by SASOL UCG involves similar reactions but in an environment that is harder to test and control Coal

  5. Surface and Underground Coal Gasification produces a low btu gas of varying composition depending on conditions

  6. Gas from UCG A very Unconventional Gas UCG Gas is multi gas composition has low btu contains moderate CO2 content Approximate comparisons Example from Hanna USA

  7. A brief History of UCG Much of the early research was Behind the Iron Curtain Russia (Former Soviet Union = FSU) Various methods developed in the FSU

  8. History of UCG • Initial Development Began • Behind the Iron Curtain • With vast coal reserves and in 1930’s limited natural gas reserves; FSU aggressively investigated opportunities for UCG • A lot of detailed science and experience stayed behind the Iron Curtain till 1970’s • FSU developed a number of techniques and gasified different ranks of coal in different geological environments but generally low rank coal at shallow depth • Important to develop a pathway from air injection hole though burn zone to gas recovery hole. Initially FSU tunneled to connect injection and gas recovery holes later they used directional drilling along seam • FSU used forward and counter current directions for injected air flow ie burn progresses in same direction as injected air or progresses towards injected air • Trials in FSU in steep dipping seams using co current combustion (Juschno-Abinsk) were moderately successful.

  9. Main Locations of Russian (FSU) UCG

  10. Summary of Russian (FSU) Data from main locations Another version compare later

  11. Early FSU Methods for UCG in Dipping Seams • Initial linkage injection hole to gas removal hole was a tunnel • Injection and gas removal holes drilled down dip in coal seam • Burn zone moves up dip with coke and rubble collapsing down dip into cavity • Roles of holes periodically reversed to ensure even burn along linkage Cavity development in steep dipping seams is similar to fixed bed surface gasification (Lurgi gasifier) with air injected at the bottom and fresh coal fed by gravity at top. Bulldoze alluvium to seal fractures limit gas leak Kreinin and Revva (1966)

  12. FSU Method for UCG in Steep Dipping Seams Initial injection holes vertical Later holes drilled below coal seams Gas recovery holes drilled in seams Vertical water recovery holes drilled into cooled rubble zone An overview of Soviet effort in underground gasification of coal Gregg et al 1976

  13. FSU Design for UCG in Steep Dipping Seams Kreinin and Revva (1966)

  14. FSU UCG Steep Dipping Seams Developed early version of horizontal drilling to connect injection and gas recovery holes Second stage air injection holes drilled in footwall clear of subsidence Kreinin and Revva (1966)

  15. FSU also developed UCG in Horizontal Seams Generally at shallow depth using vertical holes Injection air 150’C Overburden Gas recovery hole Pyrolysis products Water influx Gas losses 800-1200’Ç Pyrolysis products Coal seam Rubble 800’C

  16. FSU Vertical Drill Pattern for horizontal seams Plan views of developing geometry by stage Gas recovery hole Burn progression Air injection hole Stage 1 Form linkage along line of vertical holes counter current burn Gas flow Stage 2 Complete linkage using counter current flow Stage 3 start parallel line of holes link to first row of holes using co current flow

  17. FSU Vertical Drill Pattern into Horizontal Seam Plan view of air injection and gas recovery holes as development progresses Gregg et al 1976 An Overview of Soviet Effort in Underground gasification of Coal

  18. Recent Development in UCG geometry

  19. Recent Important Development in UCG Geometry CRIP (Controlled Retractable Injection Points) Makes use of modern horizontal drilling techniques applied to horizontal seams Coal Seam Gas moves in same direction as injected air through previous burn zone to recovery hole Must drill along base of seam Width height ratio about 6/1 therefore seam thickness controls amount of resource around each hole

  20. Development of the CRIP Method • (Controlled Retractable Injection Points) • Centralia Washington (Toni 1) 1983 • Hanna Wyoming (Rocky Mountain RM1) 1987 • Tests showed that CRIP process is capable of producing consistently high quality gas from single injection hole for extended time. • CRIP in horizontal injection hole, has advantage over vertical injection holes. Maintains air low in seam for optimal resource recovery. • Provides a method for re-ignition of coal at different locations when gas quality declines as maturing reactor begins to interact with overburden. • CRIP in sub-bituminous and lower rank coals has reached a level where remaining technical uncertainties and risk to commercial development are reduced. • RM1 CRIP module operated for 93 days and gasified over 10,000 tonnes of coal, Gas average dry product heating value of 253 kJ/mol (287 Btu/scf=2554 Kcal/m^3).

  21. CRIP adapted by British Gas (Knife edge CRIP) • Gas production horozontal holes up to 500 metres along seam drilled parallel to horizontal oxygen+steam injection holes • Injection started with a vertical hole • Injection holes completed with slotted liner + ignition source which is pulled back along hole. • Gas flows thru coal from injection hole to production hole • Prior to ignition it is possible to hydro frac the injection hole ?? • Orientation of injection and gas recovery holes drilled to take advantage of cleat geometry ??

  22. Development of UCG • Ergo Exergy, εUCG technology • Company adapted and patented FSU methodology, but not much published on εUCG process and Ignition and Injection procedures. • May be using vertical holes • Don’t know differences between FSU UCG, εUCG and CRIP • Don’t know methods used in εUCG to establish reliable connections between injection and production wells. • Don’t know how εUCG compares with CRIP in terms of reproducibility, reliability, cost

  23. UCG Activity Around the World

  24. UCG Activity around the World in 2007-2008

  25. UCG Activity around the World Interest in UCG spread around world following increase in oil and gas prices A lot of expertise is still in FSU For CO2 storage Friedmann Burton Upadhye Lawrence Livermore National Laboratory 2007

  26. Evolution of Test Site Experience Progression Trying deeper seams Trying thinner seams Trying deeper and thinner Minimum thickness “Best Practices in Underground Coal Gasification”, E.Burton, J.Friedman, R. Upadhye, Lawrence Livermore Nat. Lab., DOE Contract No. W-7405-Eng-48

  27. UCG Activity around the World • United States • More than 30 experiments between 1972 and 1989 • Introduced Continuous Retraction Injection Point (CRIP) process. • Pilots conducted at • Hanna Wyoming 1972-1973 • Hoe Creek Wyoming 1976-1979 • Centralia Washington 1981-1982 Extracts from from Potential for Underground Coal Gasification in Indiana Phase I Report to CCTR Evgeny Shafirovich, Maria Mastalerz, John Rupp and Arvind Varma1Purdue University, September 16, 2008 and other sources

  28. US UCG Projects Hanna Friedmann Burton Upadhye Lawrence Livermore National Laboratory 2007

  29. Experience from the Hanna UCG Project Wyoming 1973 One of the earliest tests outside FSU

  30. Data from the Hanna Project Air injection rate drives gas production Air injection red Gas production black 1800 Kcal/m^3 900 Kcal/m^3

  31. Location of UCG projects in Western Canada Synergia Polygen Swan Hills Laurus Energy 0 300 Km

  32. Australia Linc Energy Ltd UCG trial Chinchilla, Queensland using Ergo Exergy’s technology Project (1999-2003) demonstrated feasibility to control UCG process Gasified coal at 130 metres depth seam thickness 10 metres Gasified 35,000 tons of coal, with no environmental issues. 80 million Nm3 of gas produced at 4.5 - 5.7 MJ/m3 (121-153 BTU/sft) Maximum gasification rate 80,000 Nm3/hr or 675 tons coal/day Gas production over 30 months high quality and consistency of gas 95% recovery of coal resource; 75% of total energy recovery; 9 injection / production vertical wells; 19 monitoring wells; average depth of 140 m; Since 2006 Linc Energy Ltdco-operate with Skochinsky Institute of Mining Moscow; acquired a 60% controlling interest in Yerostigaz, which owns the UCG site in Angren (Uzbekistan) Cougar Energy Ltd plans pilot burn for a 400MW combined cycle power project Carbon Energy PL plans 100-day trial to show commercial feasibility of the CRIP UCG process Chinchilla probably air dried analysis of sub bituminous coal

  33. Location Chinchilla Project Linc Linc Energy Limited Presentation 2006 Level 7, 10 Eagle Street BRISBANE, QLD 4000 Ph: (07) 3229-0800 Email: pab@lincenergy.com

  34. Western Europe A number of UCG tests have been carried out A significant difference of these tests is depth of seams (600-1200 m) In 1992-1999, UCG project was conducted by Spain, UK and Belgium at “El Tremedal” (Spain) In 2004, DTI (UK) identified UCG as one of the potential future technologies for development of UK's large coal reserves India India has fourth-largest coal reserves in world UCG will be used to tap those India coal reserves that are difficult to extract by conventional technologies. Oil and Natural Gas Corporation Ltd. (ONGC) and Gas Authority of India Ltd. (GAIL) plan pilot projects using recommendations of experts from Skochinsky Institute of Mining in Moscow and Ergo Exergy (Khadse et al., 2007). Scheduled production is 2009 UCG Lignite coal for electric power. It is also reported that AE Coal Technologies India Pvt. Limited, a company belonging to the ABHIJEET GROUP of India, is implementing UCG Projects in India New Zealand Solid Energy New Zealand Ltd, company founded on mining coal in difficult conditions plans to use Ergo Exergy’s εUCGTM technology for low cost access to un-minable coal Japan University of Tokyo and coal companies are conducting technical and economic studies of UCG on a small scale are planning a trial soon

  35. South Africa Eskom, A coal-fired utility, is investigating UCG at its Majuba 4,100 MW power plant Ergo Exergy provides technology to build and operate a UCG pilot which was ignited in 2007 Project will be expanded in a staged manner, based on success of each preceding phase Project currently generates ~3,000 m^3/hr of flared gas. Volumes will increase to 70,000 m^3/hr early next year and be piped to power station before eventually rising to 250,000 m3/hr Some 3.5 million m^3/hr will be supplied to power station at full production that is anticipated around 2012 Eskom is moving ahead with the next phase UCG project. Declining coal reserves is one of the biggest problems facing Eskom, as it struggles to overcome a power shortages since January. Eskom plans to pipe greater volumes of gas to Majuba power station to help it become more coal efficient. Coal from nearby mines supplies the Majuba Power Station but transportation costs are high because of bad roads. UCG utilizes unmineable coal resources.  Eskom estimates there are an additional 45 billion tons of coal suitable for UCG in the country, excluding coalfields in KwaZulu-Natal province. Eskom produces about 95% of South Africa's electricity and is spending billions of dollars to expand generating capacity to meet demand from country's growing economy.

  36. Eskom Power Plants Majuba plant

  37. China China has largest UCG programSince late 1980s, 16 UCG trials previous or current Chinese UCG trials utilize abandoned coal mines Vertical boreholes drilled into abandoned galleries to act as injection and production wells Commercialization Xin Wencoal mining group has six reactors with syngas used for cooking and heating A project in Shanxi Province uses UCG gas for production of ammonia and hydrogen HebeiXin’ao Group is constructing a liquid fuel production facility fed by UCG ($112 million); 100,000 ton/yr of methanol and generate 32.4 million kWh/yr Researchers investigated the two-stage UCG process proposed by Kreinin (1990) for production of hydrogen, where a system of alternating air and steam injection is used. Experiments, conducted in Woniushan Mine, Xuzhou, Jiangsu Province, prove feasibility to use UCG for large-scale hydrogen production (Yang et al., 2008).

  38. UCG in China Rick Wan, Ph.D XinAo Group (www.xinaogroup.com) P. R. China

  39. China System Long Tunnel、Large section two Stages Rick Wan, Ph.D XinAo Group (www.xinaogroup.com) P. R. China

  40. Gasification Reactions and Implications for Gas Composition

  41. Gasification Reactions and Implications for Gas Composition • Gas composition depends on reactions initiated by introduction of Air or Oxygen and availability of Hydrogen ( in part from coal mainly from formation water) • As coal burns it provides energy to produce combustible gases CO, H and CH4 • As gas is extracted back through burn cavity different reactions take place based on temperature amount of water infiltration oxidizing or reducing conditions • Actual thickness of burn zone is thin ( <0.5 metres) because of low conductivity of coal • Rate of advance controlled by rate of injection of Air or Oxygen to drive process • 1 cubic metre of gas requires about0.4 Kg of coal or 1 tonne coal produces 2500 m^3 gas

  42. Gasification Reactions and Implications for Gas Composition Changes in composition transverse to burn direction Provides surface area for gasification reactions An Overview of Soviet Effort in Underground Clasification of Coal Gregg et al (1976) Equilibrium Calculation for Coal Gasification (From Stephens, 1980).

  43. General Gasification Zones in Burn Cavity along burn direction Initiation of cavity using counter current flow 1/De-volatilization zone 2/Combustion Zone Oxidation zone exothermic Temperature rising Coal consumed C+O2 CO2C+1/2 O2 CO 2CO+O2  2 CO2 CH4+O2 CO2+2H2O 3/Gasification Zone Reduction zone Endothermic Temperature falling until reactions stop no more coal consumed C+CO2 2 CO H2O+C  CO+H2 4/Reduction Zone Gas transport zone Lower temperature Shift conversion reactionreduces heat value of gas CO+H2O CO2+H2 methanation C+2 H2 CH4 4 1 3 2 Adapted from

  44. UCG Relationship of Reactions to Location in Burn Zone De-volatilization zone Methane evolved from coal is consumed CH4+O2  CO2+2H2O -891 kJ/mol Reaction provides heat in advance of main burn front Un-affected coal De-volatilization zone

  45. UCG Relationship of Reactions to Location in Burn Zone Combustion zone Burning at coal face provides heat Oxidation C+O2 CO2 -406 Kj/mole Partial Oxidation C+1/2 O2 CO -123 Kj/mole Main volume of heat generation zone is surprisingly thin CO2 produced to provide energy to make combustible gases Combustion zone

  46. UCG Relationship of Reactions to Location in Burn Zone Gasification zone As Oxygen is used reduction of CO2 occurs Boudouard Reaction C+CO2 2 CO +159.9 Kj/mole also reversal 2 CO+O2  2 CO2 Heat is used up to generate a gas rich in CO The Boudouard Reaction is sensitive to chemistry of ash rubble forming in burn cavity Gasification zone

  47. UCG Relationship of Reactions to Location in Burn Zone Reduction zone Water shift reaction steam enters burn zone H2O+C  CO+H2 +118.5 Kj/mole Shift conversion reaction CO+H2O  H2 + CO2 - 42.3 Kj/mole Hydrogenating gasification C+2 H2 CH4 –87.5 Kj/mole methanation CO+3H2 CH4 + H2O -206 Kj/mole Reactions use heat Temperature falling Reactions use water entering cavity to convert CO to H resulting in a lower heat value gas Reduction Zone

  48. Produced Gas Composition Implications on Processes

  49. Summary of Gas Composition for World Projects N ? Air injection Oxygen+Steam (?) injection 0 2 4 6 8 10 12 14

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