ProGaTherm designates the process developed by sciprotec for the thermal use of endogas. A step towards saving energy is to use the shielding gas (endogas) which is continuously discharged from the carburizing furnace for heating purposes, instead of uselessly flaring it off. The heating value of the shielding gas is about 1.9 kWh/m³.
Chamber and Shaft Furnace Systems
The amount of shielding gas in a batch-operated chamber furnace or shaft furnace, which is designed for a batch weight of 1000 kg, is about 15 m³/h, which corresponds to 1.9 kWh/m³ * 15 m³/h = 28.5 kW per hour. This amount is sufficient to continuously heat up within one hour a tempering furnace at 200 °C and a gross batch weight of about 600 kg steel. There is even enough thermal energy to operate a second furnace during the holding phase. Clever capacity planning makes it possible for a typical tempering holding time of up to 2 hours to clock it so several carburizing and tempering furnaces can be entirely operated with the endogas heating. In this way, the heating of the tempering furnaces is possible without additional primary energy.
Pusher-Type Furnace, Rotary Hearth, Roller Hearth Furnace and Belt Furnace Systems
The amount of shielding gas in a continuously operating plant is in the order of 50 m³/h, which corresponds to 1.9 kWh/m³ * 50 m³/h = 95 kW per hour.
Using a newly developed exhaust method, the generated process gas is exhausted (isobar) from the furnace and cooled down. A gas booster station compresses the exhausted gas to a pressure which is, for example, necessary to operate a burner. The process gas is then introduced for direct use in a thermal process. Possible applications of use are the heating of a preheating furnace, tempering furnace or also the heat treatment of a salt bath or washer. In principle, any process requiring heat can be heated using ProGaTherm.