The standard distance between the centers of the tubes arranged against the refractory walls in the radiant sections of refinery heaters is 2 tube diameters. The tube row itself is installed 1.5 tube diameters away from the wall.

Under these conditions about 66% of the radiant heat from the combustion zone is absorbed by the front area of the tubes. The refractory walls re-radiate to the backside of the tubes about 22% of the total radiation from the combustion zone. So in effect the backside of the tubes receive only 1/3 of the heat. The balance 12% (=100-66-22) gets reflected back to the combustion zone.

	The patented Ram’s Radiant Reflectors (RRR) are refractory wedges or corbels (in heater terminology). They are placed on the refractory wall between the tube centers so that they can deflect the 12% radiation to the rear of the tubes. This is simple physics.
18" long 6"tall Radiation Reflector (good for 1900 F) for a VC heater.

The result is : the backside of the tubes will transfer about 34% heat to the process fluid instead of 22%, a good 54% increase. This will even out the circumferential flux distribution to result in a 66 to 34 distribution between the front and the back.

If Ram’s Reflectors are coupled with Ram’s Studded Tubes in the same heater, the flux distribution can be evened out a lot more. These two ideas are complimentary to each other. The studded tube concept taps into the convection currents and the reflectors work on radiation deflecting more heat to the rear of the tubes.

Plan view of a model of Radiant Reflectors and Partially Studded tubes installed in the same heater:

Net effect: the heater radiant section can deliver a lot more heat to the process fluid under much milder conditions improving heater longevity as well as its on stream time.

The RRRs can be retrofitted in existing heaters. Prismatic Modules (say 6’ tall) made of ceramic fiber blanket material designed with special anchors can be carried between the tubes and impaled on the existing refractory. Adding on the reflector wedges in the design of new heaters with either castable refractory or blanket insulation is a very simple and economical procedure.

Apart from delivering more heat to the radiant section, the RRRs also reduce the exit gas temperature from the radiant section thus reducing the NOX emissions from the burners. The reduction in the exit gas temperature could also be an advantage in heaters that are running hot in the shield section.

Please send your heater data sheets and operating conditions for a free evaluation of your heater.