A PLASMATRON COAL-WATER SLURRY COMBUSTOR FOR RESIDENTIAL AND SMALL INDUSTRIAL APPLICATIONS

A FREQUENT APPROACH TO THE DESIGN OF COAL-WATER SLURRY (CWS)RESIDENTIAL/INDUSTRIAL COMBUSTORS IS TO ADAPT THE CONVENTIONAL OIL BURNER DESIGNS TO THE NEW SERVICE. TWO SEVERE DIFFICULTIES ARE ENCOUNTERED; ONE IS COMBUSTION STABILITY AND COMPLETENESS IN THESE LOW FLOW RATE/LOW VOLUMEDEVICES, AND THE OTHER IS CWS INJECTION. THUS WHAT IS NEEDED IS A SOURCE OF VERY HIGH TEMPERATURE AIR THAT WOULD FLASH-VAPORIZE THE WATER IN A CWS DROPLET, AND RAPIDLY PYROLIZE AND IGNITE THE COAL, THEREBY STABILIZING THE FLAME EVEN UNDER POOR MIXING CONDITIONS. GAS OR OIL PILOT FLAMES CANNOT ACHIEVE HIGH ENOUGH TEMPERATURE BECAUSE THEY MUST ACT AS VITIATORS. IN ADDITION, THEIR USE WOULD REQUIRE DUALFUEL STORAGE AT EACH LOCATION. A PLASMATRON CAN HEAT AN AIR STREAM TO ALMOST ANY TEMPERATURE AND DISCHARGE IT INTO THE COMBUSTION ZONE. THIS HOT AIR STREAM, WHICH CONTAINS HIGHLY REACTIVE ATOMIC OXYGEN, PROVIDES THE COMBUSTION STABILITY AND MAKES THE COMBUSTION OF CWS IN A SMALL VOLUME POSSIBLE. BASED ON THIS APPROACH, A NEW DEVICE CALLED A PLASMATRON CWS COMBUSTOR IS PLANNED. PRELIMINARY CALCULATIONS INDICATE THAT THE THERMAL GAIN (G) OF A 100,000 BTU/HR COMBUSTOR (G = THERMAL OUTPUT/ELECTRIC INPUT)IS 30 OR HIGHER. THIS MEANS THAT THE RESIDENTIAL PLASMATRONCWS COMBUSTOR (PCWSC) WOULD REQUIRE ABOUT 1 KW OF ELECTRIC POWER WHILE DELIVERING 30 KW OF THERMAL POWER. THE PHASE I FEASIBILITY STUDY IS DIVIDED INTO THREE PARTS: (1) STEADY STATE MODELING OF THE PCWSC TO DETERMINE ITS OPTIMUM OVERALLCONFIGURATION: (2) TIME DEPENDENT MODELING OF THE EVOLUTION OF THE CWS DROPLET AFTER ITS INJECTION INTO THE HIGH TEMPERATURE OXIDIZER TO DETERMINE THE REQUIRED COMBUSTOR RESIDENCE TIME; AND (3) CONCEPTUAL DESIGN OF THE PCWSC. BUILDING AND TESTING OF A PROTOTYPICAL PLASMATRON CWS COMBUSTOR IS PLANNED FOR PHASE II.