Showing posts with label process heater. Show all posts
Showing posts with label process heater. Show all posts

Tuesday, September 12, 2017

Common Types of Process Heating Systems and Equipment

Electric Tank Heaters
External Electric Vessel Heater

In all process heating systems, energy is transferred to the material to be treated. Direct heating methods generate heat within the material (e.g., microwave, induction, or controlled exothermic reaction), whereas indirect methods transfer energy from a heat source to the material by conduction, convection, radiation, or a combination of these functions. In most processes, an enclosure is needed to isolate the heating process and the environment from each other. Functions of the enclosure include, but are not restricted to, the containment of radiation (e.g., microwave or infrared), the confinement of combustion gases and volatiles, the containment of the material itself, the control of the atmosphere surrounding the material, and combinations thereof.

Common industrial process heating systems fall in one of the following categories:
Large Heat Treated Parts
Large heat treated parts - still red-hot.
  • Fuel-based process heating systems 
  • Electric-based process heating systems 
  • Steam-based process heating systems 
  • Other process heating systems, including heat recovery, heat exchange systems, and fluid heating systems. 
The choice of the energy source depends on the availability, cost, and efficiency; and, in direct heating systems, the compatibility of the exhaust gases with the material to be heated. Hybrid systems use a combination of process heat systems by using different energy sources, or different heating methods with the same energy source.

Hotfoil-EHS are skilled experts in a wide variety of process heating systems design and fabrication. Contact them at 609-588-0900 or visit their website at http://www.hotfoilehs.com.

Wednesday, August 16, 2017

Industrial Process Heating: Electric and Fuel Based

Electric heater used on industrial hopper throat.
Electric heater used on industrial hopper throat.
Process heating operations supply thermal energy to transform materials like metal, plastic, rubber, limestone (cement), glass, ceramics, and biomass into a wide variety of industrial and consumer products. Industrial heating processes include drying, heat treating, curing and forming, calcining, smelting, and other operations. Examples of process heating systems include furnaces, ovens, dryers, heaters, and kilns. Many of these systems are mature technologies used ubiquitously throughout manufacturing. Process heating is used to raise or maintain the temperature of substances involved in the manufacturing process, such as the use of heat to melt scrap in electric arc furnaces to make steel, to separate components of crude oil in petroleum refining, to dry paint in automobile manufacturing, or to process food for packaging.

Electricity-based process heating systems transform materials through direct and indirect processes. For example, electric current is applied directly to suitable materials to achieve direct resistance heating; alternatively, high-frequency energy can be inductively coupled to suitable materials to achieve indirect heating. Electricity-based process heating systems are used for heating, drying, curing, melting, and forming. Examples of electricity-based process heating technologies include electric arc furnace technology, infrared radiation, induction heating, radio frequency drying, laser heating, and microwave processing.

Gas burners for process heating
Gas burners for process heating.
Fuel-based process heating systems generate heat by combusting solid, liquid, or gaseous fuels, then transferring the heat directly or indirectly to the material. Hot combustion gases are either placed in direct contact with the material (i.e., direct heating via convection) or routed through radiant burner tubes or panels that rely on radiant heat transfer to keep the gases separate from the material (i.e., indirect heating). Examples of fuel-based process heating equipment include furnaces, ovens, kilns, melters, and high-temperature generators.

For information on any industrial heating application, contact Hotfoil-EHS at 609.588.0900 or visit http://www.hotfoilehs.com.

Friday, June 23, 2017

Process Heating: Induction

Induction Heater
Induction heating coils around large pipe
in preparation of welding.
The principles of induction heating have been applied to manufacturing operations since the 1930s, when the first channel-type induction furnaces were introduced for metals melting operations. Soon afterward, coreless induction furnaces were developed for melting, superheating, and holding. In the 1940s, the technology was also used to harden metal engine parts. More recently, an emphasis on improved quality control has led to increased use of induction technology in the ferrous and nonferrous metals industries.

In a basic induction heating setup, a solid state power supply sends an alternating current (AC) through a copper coil, and the part to be heated is placed inside the coil. When a metal part is placed within the coil and enters the magnetic eld, circulating eddy currents are induced within the part. These currents ow against the electrical resistivity of the metal, generating precise and localized heat without any direct contact between the part and the coil. 

An induction furnace induces an electric current in the material to be melted, creating eddy currents which dissipate energy and produce heat. The current is induced by surrounding the material with a wire coil carrying an electric current. When the material begins to melt, electromagnetic forces agitate and mix it. Mixing and melting rates can be controlled by varying the frequency and power of the current in the wire coil. Coreless furnaces have a refractory crucible surrounded by a water-cooled AC current coil. Coreless induction furnaces are used primarily for remelting in foundry operations and for vacuum refining of specialty metals.

Induction heating power console
Induction heating power console (Hotfoil-EHS)
Channel furnaces have a primary coil wound on a core. The secondary side of the core is in the furnace interior, surrounded by a molten metal loop. Channel furnaces are usually holding furnaces for nonferrous metals melting, combined with a fuel- red cupola, arc, or coreless induction furnace, although they are also used for melting as well.

The efficiency of an induction heating system for a specific application depends on several factors: the characteristics of the part itself, the design of the induction coil, the capacity of the power supply, and the degree of temperature change required for the application.

Induction heating works directly with conductive materials only, typically metals. Plastics and other nonconductive materials often can be heated indirectly by first heating a conductive metal medium that transfers heat to the nonconductive material.

With conductive materials, about 80% of the heating effect occurs on the surface or “skin” of the part. The heating intensity diminishes as the distance from the surface increases, so small or thin parts generally heat more quickly than large thick parts, especially if the larger parts need to be heated all the way through.

Induction heating can also be used to heat liquids in vessels and pipelines, primarily in the petrochemical industry. Induction heating involves no contact between the material being heating and the heat source, which is important for some operations. This lack of contact facilitates automation of the manufacturing processes. Other examples include heat treating, curing of coatings, and drying.

Induction heating often is used where repetitive operations are performed. Once an induction system is calibrated for a part, work pieces can be loaded and unloaded automatically. Induction systems are often used in applications where only a small selected part of a work piece needs to be heated. Because induction systems are clean and release no emissions, sometimes a part can be hardened on an assembly line without having to go to a remote heat treating operation.

Thursday, December 22, 2016

External Industrial Electric Tank Heating

epoxy laminated panel heaters
Epoxy laminated panel heater installation.
If you’re looking for an excellent external tank heating solution you may want to consider epoxy laminated panel heaters (ELPs). The heaters provide a low watt density heating profile, and along with their inherent low mass,  ELPs provide excellent thermodynamic performance.

These electric heating panels use a flat foil resistive element laminated in a multi-layer fiberglass “sandwich” using epoxy resin. Manufactured under tightly controlled heat and pressure to assure bonding and structural integrity, the resulting heater is a water-proof and durable semi-flexible heating panel.

Epoxy laminated panels are used in a variety of applications, from freeze protection to process heating. They are used on either vertical or horizontal metallic or non-metallic tanks with diameters of 48" and above. They are also applied in dry or wet areas, corrosive environments, and carry FM approval for hazardous area use.

No special tools or skills are required, so they are quick and easy to install. Typically the ELPs are installed by banding them to the tank with metal bands or polyester straps, taking just a few minutes. After installation, adhesive aluminum tape should be applied to the edges of the heaters to act as a seal, preventing thermal insulation becoming trapped between the heating panels and the tank.

For more information contact:

HotfoilEHS
2960 East State Street Ext.
Hamilton, NJ 08619
Phone # 609.588.0900
Fax # 609.588.8333
www.hotfoilehs.com
Email: dap@hotfoilehs.com

Saturday, October 22, 2016

Freeze Protection and Temperature Maintenance for Metallic & Non-Metallic Tanks and Vessels

Hotfoil ELP heating panel construction
Hotfoil ELP heating panel construction.
With winter around the corner, manufacturing plants need to consider the possibility of freezing or low process temperatures effecting outdoor storage tanks and transfer vessels. The most common approach is to install electric heating panels on the outer surface of these tanks and vessels to prevent the contents from freezing. Lower than normal ambient temperatures can also have negative effects on the flow of liquids for a given process. In these situations it is important to maintain liquids at a constant temperature. Electric heating panels are easy to install on tanks and vessels and provide the flexibility to heat a large area of the tank surface. They can also be used to target heat to specific areas on a tank.

Typical Hotfoil ELP heating panel placement
Typical Hotfoil ELP
heating panel placement
Hotfoil ELP heating panels are suitable for installation on metallic tanks and vessels for freeze protection or process temperature maintenance up to 79°C/175°F. They incorporate flat foil resistive elements that are laminated by heat and pressure in a multi-layer fiberglass construction with epoxy resin. The resulting electric heater design is a semi-flexible panel that is waterproof and durable. They are used in a variety of heating applications spanning from freeze protection to process heating with exposure temperatures ranging from -40 F to +212 F.

ELP heating panels can be used on either vertical or horizontal tanks with diameters of 48" and above, with either metallic or non-metallic construction.  They can be used in dry, wet, or corrosive environments, are available in 120 and 240 volts, and are approved for hazardous and non-hazardous areas.

For more information, visit www.hotfoilehs.com or call 609.588.0900

Tuesday, December 15, 2015

Self Regulating Heating Cable

Self regulating heating cable
Self regulating heating cable
Self-regulating heating cables automatically adjust their power output to compensate for temperature changes. The outer jacket, braid, and inner jacket provide mechanical, chemical, and electrical protection. The magic happens in the conductive core that surrounds the two parallel conductors. As the ambient temperature drops, the core contracts microscopically, and the number of electrical paths through the core increases, more heat is produced. Conversely, as the ambient temperature rises, the core expands and has fewer electrical paths, and less heat is produced. At a certain temperature, almost all the electrical paths are disrupted and power output is close to zero. A self-regulating heating cable adjusts its power output along its entire length. That's what makes it a safe and reliable solution for many applications.

Self-regulating cable is flexible, and is much easier than constant wattage cable because it can be cut-to-length in the field, terminated, and (if needed) overlapped without fear of burnout. This is very valuable in areas where complex piping systems exist with many valves, tanks and vessels.

As with any heat tracing cable, proper wattage requirements need to be calculated. In order to properly calculate wattage, the following information must be known:
  • Pipe size and material
  • Insulation type and thickness
  • Maintain temperature
  • Minimum ambient temperature
  • Minimum start-up temperature
  • Service voltage
  • Chemical environment
  • Maximum intermittent exposure temperature
  • Electrical area classification
Once this information is known, most manufacturers will have wattage calculators where you can simply use the above data to calculate your requirements.

Wednesday, September 30, 2015

Epoxy Laminated Panels for Industrial Tank Heating

epoxy laminated heater
Epoxy laminated heater for tanks
Need a way to maintain process temperature for a holding tank? Looking for something easy to install and connect? Consider an epoxy laminated electric heating panel.

These heaters use a flat foil resistive element which is laminated in a multi-layer fiberglass construction using epoxy resin. The manufacturing process is done under tightly controlled heat and pressure to assure bonding and structural integrity.  The resulting electric heater design is a semi-flexible panel that is waterproof and durable.

Epoxy laminated panel (ELPs) are a very versatile option for tank heating. ELP heating panels can be used in a variety of applications from freeze protection to process heating with exposure temperatures ranging from -40 F to +212 F. ELP heating panels can be used on either vertical or horizontal tanks with diameters of 48" and above, with either metallic or non-metallic construction. They can also be used in dry, wet, or corrosive environments, as well as for hazardous and non-hazardous areas. 

epoxy laminated heater
Installed view of epoxy laminated heater.
They are quick and easy to install and require no special tools or skills. Heaters are usually installed by banding them to the tank with metal bands or polyester straps, which takes only a matter of minutes. After installing the heating panels, adhesive aluminum tape should be applied to the edges of the heaters acting as a seal. This will prevent thermal insulation becoming trapped between the heating panels and the tank.

The heaters provide a low watt density heating profile, and along with their inherent low mass,  ELPs provide excellent thermodynamic performance. 

For more information contact:

HotfoilEHS
2960 East State Street Ext.
Hamilton, NJ 08619
Phone # 609.588.0900
Fax # 609.588.8333
www.hotfoilehs.com
Email: dap@hotfoilehs.com