THE GASIFICATION OF COAL

GAS MADE FROM COAL COULD SUBSTITUTE FOR NATURAL GAS IF THE OLD TECHNOLOGY OF COAL GASIFICATION COULD BE IMPROVED TO GIVE THE PRODUCT THE HEATING VALUE OF NATURAL GAS (1,030 BRITISH THERMAL UNITS PER CUBIC FOOT). THE UNENRICHED GAS FROM COAL COULD ALSO SERVE WELL IN MANY INDUSTRIAL APPLICATIONS. THE CONTINUING IMPROVEMENT IN COAL GASIFICATION TECHNOLOGY IS REVIEWED AND THE LURGI AND KOPPERS-TOTZEK PROCESSES (WHICH ARE COMMERCIALLY AVAILABLE) ARE DISCRIBED. THE FORMER IS A PRESSURIZED PROCESS IN WHICH WHICH SIZED COAL DESCENDING INTO THE GASIFIER IS FIRST DRIED AND THEN CARBONIZED BY REACTION WITH OXYGEN AND STEAM. IN THE GASIFIER'S BOTTOM LAYER, THE REMAINING CARBON IS BURNED TO PROVIDE HEAT FOR THE REACTIONS PROCEEDING ABOVE. THE KOPPERS-TOTZEK PROCESS EMPLOYS STEAM AND OXYGEN IN THE GASIFICATION STEP AND PROCEEDS AT ATMOSPHERIC PRESSURE. IT WILL WORK WITH ANY TYPE OF COAL. NEITHER OF THE COMMERCIAL PROCESSES YIELDS A GAS WITH THE HEATING VALUE OF NATURAL GAS, BOTH PROCESSES REQUIRE A METHANATION STEP IN WHICH THE GAS FROM THE COAL IS PASSED OVER A NICKEL CATALYST. SEVERAL NEW METHODS ARE BEING INVESTIGATED AND TWO HAVE REACHED THE DEMONSTRATION STAGE. THE BASIC STEPS IN TWO PROCESSES ARE CHARTED IN A DIAGRAM WHICH ILLUSTRATES HOW THE COAL IS PREPARED AS NECESSARY AND THEN DEVOLATALIZED. THIS ENTAILS HEATING IT IN THE ABSENCE OF AIR SO THAT IT DECOMPOSES CHEMICALLY, YIELDING VARIOUS GASES AND CHAR. ALSO ILLUSTRATED ARE THE HYGAS PROCESS, THE CARBON DIOXIDE ACCEPTOR PROCESS AND THE SYNTHANE PROCESS. THE BI-GAS PROCESS IS OUTLINED. UNDERGROUND COAL GASIFICATION IS DISCUSSED TOGETHER WITH SOME NEW TECHNOLOGICAL APPROACHES SUCH AS THE USE OF EXPLOSIVES AND DRILLING WITH LASERS.

Media Info

  • Features: Figures;
  • Pagination: p. 19-25
  • Serial:
    • Scientific American
    • Volume: 230
    • Issue Number: 3
    • Publisher: Scientific American Incorporated
    • ISSN: 0036-8733

Subject/Index Terms

Filing Info

  • Accession Number: 00202435
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 19 1974 12:00AM