OCR Text |
Show RESULTS 1. Best combustion was obtained around 4> = 1 (0.9 < $ < 1.1). Below <}> = 0.7, the combustion resulted in very low carbon utilization. 2. Combustion could be sustained with preheat temperature as low as 700 F (which yields approximately 550 F temperature at the CWM injection plane), below which the flame became intermittant. At low firing rates, the low preheat temperatures resulted in decrease of carbon utilization (see Figure 7). 3. For the burner tested, AFR (m-atomizing air/m-fuel) of about 0.2 gave best combustion characteristics. 4. The oxidizer velocity influences mixing of oxidizer and CWM and hence combustion. Oxidizer inlet velocity around 400 ft/sec is required to ensure good combustion. Figure 8 shows the dependence of carbon utilization on oxidizer velocity, 5. The burner designed for 10 MM Btu/hr rating operated very well up to 15 MM Btu/hr input and could be derated to 5 MM Btu/hr input. However, better carbon utilization was achieved at the upper range. 6. Enthalpy probe measurements indicated combustion gas temperatures around 3000 F, in agreement with calculations. 7. Maximum slag recovery obtained was 78%. 8. Very good carbon utilization was obtained under optimum operating conditions. 9. No operational or hardware problem was encountered. The slurry feed system and the burner operated without plugging. Post-test inspection revealed good slag deposition. It was demonstrated that stable combustion can be sustained in a slagging combustor with the CWM burner designed and fabricated for the purpose. Apart from minor inconsistencies from barrel to barrel, the ARCOAL did not cause any plugging problems, and burned satisfactorily. No pumping or handling problems were experienced. It was demonstrated that the burner 10 |