Watlow Gas Regeneration Heater Helps Refinery Meet Clean Air Act Regulations

Problem:

Watlow Gas Regeneration Heater Helps Refinery Meet Clean Air Act Regulations
To comply with the Clean Air Act, a coal-fired power plant needed to heat flue gas to 455°C (850°F). The company had never used electric heat in its processes, so they were unsure how to specify their requirements.

Solution:

Watlow engineered a customized design that would meet the customer's needs. This included:
  • Three large duct heater assemblies
  • Seven small duct heater assemblies
  • Five control panels

The large heater assemblies are rated at 375 kW (125 kW each). Each assembly has its own SCR power control, high-limit device and contactor for high-limit shutdown. Watlow custom manufactured the duct heaters and frames, building an extra-long stand-off section because of the high temperatures. The elements were designed to be individually replaceable, with a special seal to allow the system to operate at low pressure without leaking. Spare elements were wired in at the customer's request.

A skid assembly was also included for ease of mounting. To allow for thermal expansion of almost two inches (50 mm), slots were added to the base of the skid assembly.

The key to success in this application was Watlow's ability to provide the engineering expertise the customer lacked, and to add custom options that enhanced the overall performance of the system.