Electrical heater radiant box purge and pressure relief

An electrical heater system, comprising:

• an electrical heater comprising an enclosure containing a refractory, electrical heating elements, and a process coil;
• a stack having an air draft inlet proximate a lower portion of the stack and a flue gas outlet at a top of the stack;
• a fluid conduit fluidly connecting the enclosure to the stack;
• a pressure relief mechanism configured for exhausting fluid from the enclosure into the fluid conduit;
• and
• a purge gas distribution system disposed in a floor of the enclosure or in a wall along the floor of the enclosure.

An electrical heater system, comprising:

• two or more electrical heaters, each comprising an enclosure containing refractory, electrical heating elements, and a process coil;
• a stack having an air draft inlet proximate a lower portion of the stack and a flue gas outlet at a top of the stack;
• a fluid collection system fluidly connecting each of the enclosures to the stack and including inlet fluid conduits, a header, and a header outlet, the fluid collection system comprising:
• a pressure relief mechanism disposed proximate a fluid outlet of each enclosure, each pressure relief mechanism configured for exhausting fluid from a respective enclosure into a respective inlet fluid conduit;
• a header fluidly connecting two or more inlet fluid conduits, configured for receiving fluids from each of the two or more inlet fluid conduits and directing a flow of received fluids to the header outlet;
• a flame holder configured for permitting fluid to flow from the header outlet into the stack while restricting flow of air or flame into the fluid conduit;
• and
• a pilot disposed within the stack proximate the flame holder.

A method of operating an electrical heating system including an enclosure containing refractory, electrical heating elements, and a plurality process coils, the method comprising:

• supplying electrical energy to the electrical heating elements to provide radiant energy to the plurality of process coils;
• passing a process fluid through the plurality of process coils and heating the process fluid via the radiant energy;
• detecting a leak or rupture of a first of the plurality of process coil introducing a leaked process fluid into the enclosure;
• directing the leaked process fluid through an outlet of the enclosure into a fluid conduit and from the fluid conduit to a refractory inlet of a stack, the refractory inlet being disposed intermediate a draft inlet and a flue gas outlet of the stack;
• and
• igniting the leaked process fluid within the stack via a pilot disposed proximate the refractory inlet.

A method of shutting down an electrical heating system including an enclosure containing a refractory disposed on walls, ceiling, and floor of the enclosure, electrical heating elements, and one or more process coils, the method comprising:

• supplying electrical energy to the electrical heating elements to provide radiant energy to the one or more process coils and the refractory, including the refractory floor;
• terminating the electrical energy being supplied to the electrical heating elements;
• heating a purge gas within a distribution system disposed in the refractory floor;
• and
• introducing heated purge gas into the enclosure.