Electric Process Heaters

Armstrong/Chemtec brings more than 50 years of process heat transfer experience in petrochemical industries to the design of electrically heated exchangers.  Our extensive heat transfer and process industry experience is coupled with the knowledge base of the world's two premier heat transfer research organizations, HTRI and HTFS, to bring an optimum solution to your most difficult process problems.  Each of our electric heaters is custom designed for your specific process duty.  Our equipment is not sized from a table of watt density; disregarding flowrate, pressure, temperature differences, fouling, or other special process concerns.  We design each electric heater just the same as our other heavy duty industrial heat transfer apparatus, allowing for the fact that it is electrically heated.

Increasingly, electric heating is used for high temperature, heavy duty industrial services.  Process plants must run continuously, often under difficult circumstances.   Many electric heaters are made for "commercial" type light duty, and are simply not up to the demanding conditions found in oil refineries and petrochemical plants.

Combined with our thermal design experience is an extensive fabricating background with the most exacting clients in the world.  We work in all international markets and are experienced with most mechanical and electrical design codes.

Unique Features and Advantages of Electric Heaters

• Clean operation - no pollution or emissions

• 100% energy conversion

• Extremely fine control with very quick response times

• Equipment can be sited in hazardous areas

• Often low initial capital cost compared to other heat transfer equipment

• Unlimited turndown

• Ideal for heating fluids to high temperatures
  

Electric "Sheathed Element Type" Heaters

These bare sheathed element electric heaters are used in instances where there is a high heat transfer rate from sheath to process fluid or in cases where finned elements may give too high a pressure drop or present cleaning problems.  These heaters can be used to heat gases (to temperatures as high as 1200 F) or liquids.   Using advanced methods to determine sheath temperature, resistance wire temperature, and pressure drop, Armstrong designs ensure reliability and long life while optimizing heater performance and configuration.  Armstrong/Chemtec also manufactures electric heaters for widely licensed refinery processes.

These heaters feature the following:

• A terminal box/tubesheet standoff distance to allow wiring and terminal connections to operate at low temperatures and also to avoid chance of product leakage into the terminal box.

• Thermocouples welded or brazed to the element sheath to monitor element temperature and allow power shutdown if process upset or other condition causes high element temperature.

• All elements sealed for moisture protection to avoid element failures and start-up delays.

ELECTROFIN Heaters

These finned element heaters are especially suitable for process conditions or fluid properties result in a low heat transfer rate from sheath to process fluid.  The fins minimize sheath temperature and thereby reduce the possibility of element burnout and product degradation.  These heaters have all the features of our unfinned element electric heaters with the added advantage of packing significantly more heat transfer surface into a smaller diameter shell.

The fins are welded to a thick (0.095 inches) sheath to provide robustness and corrosion resistance.  Because of the thick sheath and welded fins, this heater is very durable and provides long life.  A range of fin heights, number of fins per element, and the fact that each element is a complete three-phase circuit also make this type of heater extremely versatile.  This heater is excellent for heating gases, viscous liquids and two-phase mixtures of gases and liquids.

Impedance Heaters

Armstrong/Chemtec impedance heaters are direct electric heaters for process fluids in which a metallic pipe transmits electric current and simultaneously has pressurized fluid flowing along its length. The resistance of the fluid carrying pipe produces heat which is absorbed by the fluid in contact with the pipe’s inner surface. In this equipment, the pipe acts as: the pressure containment vessel, the heating element, and the heat transfer surface. Our design prohibits current from entering connecting piping without special electrical isolation devices.

Our impedance heaters have been used in a wide variety of difficult process applications such as heating supercritical water and other fluids, high temperature gas heating, and in tubular reactors requiring heat input. Armstrong/Chemtec impedance heaters have all the desirable features of normal electric heaters and they: (1) minimize the quantity of expensive pressure-containing materials, (2) have NO susceptibility to moisture problems and (3) contain NO small diameter resistance wires that are sensitive to burn-out.

Radiant Heaters

In our radiant heaters, electrical energy is converted to heat and transferred to the process fluid by banks of elements radiating to the process vessel or tube.    Electric radiant heaters consist of an inner vessel or tube which contains the process fluid or material to be heated.  The radiant electric elements are separated from the inner vessel by an air gap of several inches and are attached to ceramic fiber insulation (8-12 inches thick).  The outer steel casing adds rigidity and supports the ceramic insulation and elements.

These electric radiant heaters are used for very high temperature heating (up to 2000 F) with normal materials, batch heating, or regeneration of catalyst beds or desiccants.  Armstrong has significant experience in designing and manufacturing this type of heater.  We utilize our extensive heat transfer background, results of in-house testing, and advanced analysis techniques to accurately assess all the relevant temperatures (elements, furnace wall, and inner vessel) to assure safe operation and long element life and avoid process fluid degradation.

Control Panels

As a complement to our supply of electric heaters, Armstrong/Chemtec manufactures control panels.  We offer thyristor or contactor type control panels depending upon your application.  Since all of our equipment is custom-designed and built, our control panels are available with any control components or circuitry which you may require. 

Like our other equipment, Armstrong/Chemtec control panels are built for industrial use.  All the components we use are proven at industrial sites, heavy duty and conservatively sized power cabling is used, and panel layout is planned for ease of installation and maintenance.  Controls can be CSA certified or provided in enclosures suitable for use in hazardous areas.