Electrical resistance heat treatment uses alternating current electricity to heat soil and groundwater, and evaporate contaminants. ERH is effective in a variety of lithologies, including unconsolidated and sedimentary soils, and can be applied in the vadose zone and saturated zone. Unlike conventional thermal remediation methods, which use air circulation to distribute heated water and waste gas throughout the system, ERH does not require ducts to transport the heated material. Consequently, ERH systems are typically much more cost-efficient to operate than forced-air systems.

What is the principle of resistance heating?

The majority of electric heating elements used in industrial applications are made from metal wires or ribbons, generally known as resistance wire. The wires are coiled tightly or flattened to create the desired heating characteristics. Common metal alloys for electric heating elements include nickel-chromium (NiCr), iron-chromium aluminum, Kanthal, and cupronickel. More recently, ceramic heating elements have become more prevalent in the market. Ceramic heaters work using the same principles as metal heating elements, except that they are made of high-density PTC ceramic plates.

Electrical heating elements are a key component of electric heating equipment, such as metal furnaces and salt bath furnaces. They convert electricity into heat by passing a current through the element and utilizing convection, conduction, or radiation to generate the desired heating conditions in the furnaces that they are part of.

Traditional low voltage electric resistance heat treatment is often applied for preheat and local Post-weld Heat Treatment (PWHT) operations on mechanical components. The process drives off moisture and hydrogen that could otherwise cause porosity and cracking in the metal, and reduces thermal stress by lowering the rate of weld hardening.