NEW ALTERNATIVES TO MANAGE HOT SURFACE IGNITION TEMPERATURES FOR TRACE HEATING IN EXPLOSIVE ATMOSPHERES

The design of high temperature electric trace heating in hazardous areas can be a major challenge. This is particularly true when process temperatures approach the area classification limit, restricting the allowable temperature differential between what is heated and the surface temperature of the electric trace heaters. While there are methods that can be applied to address the challenges, they have traditionally been bound by the attributes of the trace heaters. In many cases, this leads to designs that are difficult to install, maintain, and often increases the cost of the overall solution. This paper will present alternative methods to deal with these challenging situations using recently improved heater constructions and controller algorithms. Used with engineering design software that can accurately predict heater surface temperatures, these options provide the design engineer with improved flexibility in creating solutions. Examples of current projects underway will illustrate that designs incorporating these new technologies result in significant improvements in constructability, and a reduction in installed costs over conventional approaches.