North American TwinBed ® II Burner Transition and Regenerator Refractory Dry-Out Procedure
Instructions 4343-16
DRY-OUT USING AUXILIARY BURNERS 1. If necessary, add additional thermocouples specifically for monitoring the temperature during the cure. 2. After the auxiliary burners are in operation, start cycling the TwinBed II burners with cooling air and combustion air only at 20% of the burner’s rated air flow capacity. If the refractories used in the furnace construction may be expected to egress salts or condensable compounds during the heatup, be conscious of the fact that exhausting through the TwinBed II burners may capture these compounds in the beds and exhaust piping, leading to plugging and/or corrosion, necessitating cleaning of the regenerators and possibly the piping after dryout is complete. 3. Adjust the auxiliary burners as required to maintain appropriate temperature set points and ramp rate. 4. Adjust the combination of the TwinBed II exhaust and the resistance on the furnace stack to maintain the desired furnace pressure (typically positive) without overheating the TwinBed II exhaust components. 5. Before the furnace gets to 400°F, light the pilots on the TwinBed II burners. It may be necessary to stop burner cycling to adjust pilot operation. CAUTION! Standards compliant functioning of the Flame Detection System can be compromised if the pilot system is not configured and adjusted strictly in accordance with the information outlined in Sheet 4343-3.
INSTRUCTIONS
The refractory linings of all TwinBed II burners, transitions and regenerators have been wet cured and oven dried at Fives North American Combustion, Inc. facilities. To prevent damage, these oven dried components must be stored above 40°F and protected from moisture. The heatup procedures used during the commissioning of a newly installed burner can have a significant impact on the longevity of the product. Ideally, the TwinBed II refractory will be cured as the furnace refractories are themselves being cured - heated to their final working temperature to a cycle defined by the refractory manufacturer. A preferred 100°F per hour ramp rate for TwinBed II will allow the refractory to stress relieve itself and reduce the potential for spalling and/or excessive cracking. When steaming from the burner structure (not the exhaust piping) is observed, the temperature should be held until steaming stops, and then the ramp continued at the 100°F per hour rate until the target finish temperature is reached. It is completely normal to see some moisture drip from the exhaust piping when operating with low furnace and exhaust temperatures as a result of condensation of the water vapor in the exhaust gases. This document addresses dry-outs using auxiliary burners and also those situations where the TwinBed II burners themselves will be used to provide the heat to dry out the furnace structure. It is also possible that a combination of the two procedures may be used. IMPORTANT NOTE: The temperatures, times and ramp rates given here consider the treatment of the TwinBed II refractory materials only. The temperature, time, and ramp rate requirements of the furnace structure and refractories are outside the scope of this document but must be investigated and an integrated procedure developed.
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