Development of a reliable method for in-situ ignition of coal through a lined borehole

Conference · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6018726

Britten, J A; Thorsness, C B; Upadhye, R S; Field, J E

Reliable permeability enhancement of a coal seam necessary for successful underground coal gasification (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. The controlled retracting injection point (CRIP) method developed by Lawrence Livermore National Laboratory 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. For structural and flow conductance reasons the horizontal borehole must be lined with steel pipe, which the CRIP igniter must be able to burn through. Other considerations crucial to the successful CRIP operation are the method used for the remote ignition of the gaseous reactants, the time required to burn through the pipe as a function of ambient and flow conditions, and the degree of backburning of the steel pipe during the procedure. This paper summarizes previous field and laboratory development of the CRIP system, and describes recent efforts which tested burner designs and breakaway burner heads for in situ backup use, and measured burnthrough times for stainless steel pipes for a variety of gas flow rates and compositions. 6 refs., 6 figs., 1 tab.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6018726
• Report Number(s): UCRL-93888; CONF-8604144-1; ON: DE86008384
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
ALKANES
ALLOYS
CHROMIUM ALLOYS
COAL GASIFICATION
CONTROL
CORROSION RESISTANT ALLOYS
DIRECTIONAL DRILLING
DRILLING
FIELD TESTS
GASIFICATION
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
IGNITION
IN-SITU GASIFICATION
IN-SITU PROCESSING
IRON ALLOYS
IRON BASE ALLOYS
METHANE
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
PROCESSING
PROPANE
SILANES
SILICON COMPOUNDS
STAINLESS STEELS
STEELS
TESTING
THERMOCHEMICAL PROCESSES