Combustion Catalog | Fives North American

Sheet 4200-1 Page 4

Initial Firing Note: If at any time during the firing cycle “steaming” is observed, hold the temperature constant until the “steaming” dissi- pates, then resume the remaining schedule beginning from the time the “steaming” hold began.

1. Begin the dryout by lighting the burner pilot and increasing pilot gas flow as needed for the desired refractory or hot mix temperature. If “glowing” of the pilot or its connection boss occurs during firing, a small fan or other air supply directed upon the hot area should be used to keep the pilot cool during extended operation. As temperature requirements increase, light the radial burner to increase the input. 2. If temporary thermocouples cannot be installed in the reaction chamber refractory or at its exit, the process or other system temperatures may be used (with appropriate allowances for temperature losses) to infer the reaction chamber refractory temperatures. As an alternate, the burner hot mix temperature may be predicted by the overall fuel to air ratio as described previously. Remember, it is the temperature inside the reaction chamber that needs to be maintained, not an overall process temperature. 3. The following time and temperature schedule is recommended : 3 hour ramp from 60°F to 300°F 6 hour soak at 300°F 3 hour ramp from 300°F to 500°F 6 hour soak at 500°F 14 hour ramp to 1200°F (50°F per hour) 6 hour soak at 1200°F 1 12 hour ramp to 1800°F (50°F per hour) 6 hour soak at 1800°F X hour ramp to operating temperature (100°F per hour) 2 12 hour (minimum) cooling period from maximum temperature to ambient at a maximum of 150° F per hour unless starting production

1 This soak period may be eliminated when the application dœs not require cyclic operation or when prefiring will not exceed 2000°F.

Initial Firing after Optional Pre-fire Dryout or Cold Restart Cold restart is defined as starting the burner system when the reaction chamber refractory is below 1000°F. The refractory is assumed to be 60° to 90°F prior to lighting. NOTE: Pre-firing refractory results in permanent linear change to the material. Cracking in both longitudinal and circum- ferential directions up to 3⁄16 " wide may be observed after the chamber is cooled. When the chamber is reheated during operation, the refractory will expand, decreasing the width of these cracks. Rapid heat and cool cycles will increase cracking and decrease the life expectancy of the refractory. 2 No soak period required. Note that typical LEx, LE and GLE applications are expected to operate with hot mix tempera- tures lower than 2800°F and the lean fuel-to-air ratio required to achieve the design maximum hot mix temperature is intended to be an operating limit for the particular system. Only exceed 2600°F after consultation with Fives North American Combustion, Inc. on the specific operational settings for the system. In no case exceed 2800°F for Standard Dense Castable or 3000°F for High Temperature, Low Cement Castable as damage to both burner internals and refrac- tories may result.

1. Light the burner and hold at low fire.

2. Increase burner firing rate such that the reaction chamber refractory will reach 400°F in one (1) hour. For chambers below 60°F, ramp to 400°F at a rate of 100°F per hour.

3. Increase temperature set point by 300° to 400°F per hour until process temperature is achieved.

CONTACT T +1 800 626 3477 - F +1 216 373 4237

Fives North American Combustion, Inc. 4455 East 71st Street - Cleveland, OH 44105 - USA

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