- Author
- Britten, J. A. | Thorsness, C. B. | Upadhye, R. S. | Field, J. E.
- Title
- Development of a Reliable Method for In Situ Ignition of Coal Through a Lined Borehole.
- Coporate
- Lawrence Livermore National Lab., Livermore, CA
- Sponsor
- Department of Energy, Washington, DC
- Contract
- W-7405-ENG-48
- Book or Conf
- Combustion Institute/Canadian and Western States Section. Spring Meeting, 1986. April 27-30, 1986., Banff, Alberta, Canada, 1-20 p., 1986
- Keywords
- ignition
- Abstract
- Reliable permeability enhancement of a coal seam necessary for successful underground coation (UCG), can be achieved by drilling a horizontal borehole low in the seam connecting gas injection and production wells. Economic considerations dictate that the number of burn modules per horizontally drilled hole be maximized and gas quality remain relatively constant. For these reasons the controlled retracting injection point (CRIP) method was developed by Lawrence Livermore National Laboratory. The CRIP method involves the insertion of a small-diameter retractable igniter tube terminated by a burner/nozzle assembly into the deviated borehole. A gaseous fuel is introduced in this tube to burn in an outer oxidant flow at the nozzle and ignite the coal at this point. As the UCG cavity develops to encompass inert overburden and the quality of the produced gas begins to drop, the small tube is retracted to a new point upstream and the coal ignited here to start a new UCG module. In this way a number of modules can be gasified from the same borehole, and the produced gas quality can be maintained for relatively long periods of time.