Brief Technology Description
Minfurn is a new generation energy efficient furnace for regeneration of activated carbon. It uses Direct Resistive Heating technology that generates heat inside the carbon bed by passing electric energy resulting in maximizing the energy utilization.
Next Steps Required
Minfurn technology is proven for regeneration of activate carbon in gold mines world-wide. Tests using activated carbon with an origin in water industry has successful been completed for one water treatment plant in South Africa. Further testing is required to demonstrate the operation of Minfurn on continuous basis for regeneration of carbon in a water treatment plant.
Mintek is a parastatal research institute based in Randburg since 1934. MINTEK has become a leading provider of minerals processing and metallurgical engineering products and services to industries world-wide.
Detailed Technology Description
Minfurn uses direct resistive heating to achieve reactivation of fouled carbon. To achieve the desired temperature, an electrical current is passed through the carbon bed inside the Minfurn which in turn generates heat and the temperature required for regeneration. The optimum temperature is maintained by regulating the temperature of the bed itself, rather than using thermocouples to control the temperature of a chamber. Since, the electrical resistivity of carbon bears an inverse relationship to its temperature, the current through the furnace is used as an indication of temperature. The discharge rate is regulated to keep the current (temperature) constant. This ensures a constant and instantaneous match between the carbon throughput and the power required for maintaining a constant temperature profile.
Regeneration of activated carbon used in gold mines and water treatment plants
Direct resistive heating technology generates heat inside the carbon bed which results in minimal heat loss and maximizes the energy utilization making Minfurn a highly energy efficient furnace for regeneration of activated carbon. Minfurn has several advantageous over conventional carbon regeneration equipment:
- Continuous operation
- Easy Startup and Shutdown
- Smaller foot-print than equivalent kilns and batch operated furnaces
- Fewer moving parts, thus lower maintenance cost and break downs
- Efficient energy utilization (0.6 kWh/kg *of regenerated carbon; excludes pre-drying)
- Refractory walls that resist high temperature and corrosion
- A unique control strategy that does not rely on thermo-couples to maintain temperature
- Owing to its small size, simplicity in operation and energy efficiency, the Minfurn is economical to construct and efficient to operate
Testing and Demonstration Results
Minfurn units are installed worldwide in gold mines. The regenerated carbon from Minfurn can achieve activity of about 95% to that of the virgin carbon.
Papers and Publications
The development and performance of the Minfurn carbon regeneration furnace By – P.J. van Staden and T W Walker, Journal of The South African Institute of Mining and Metallurgy, March 1993, pp 61-70
Patent protection lapsed for SA Patent No. 92/2444