A. Carbon Blocks
HEG also makes Fine Grain Carbon Blocks for various applications on special orders. These blocks are used by the customers to make value added products like Heat Exchangers, etc.
B. Graphite Specialities
HEG has a graphite Speciality division to cater to the requirements of customers who need Graphite Products in specific sizes and shapes. These are manufactured to individual customer requirements.
C. Activated Carbon Fabric (ACF)
ACF is a flexible form of activated carbon. The activated carbon fabric is mechanically weak but highly porous in nature. Due to this, it possesses unique characteristics as compared to conventional activated carbon, which is commonly used in granular, palletised, powdered and moulded form. Due to a thin fibrous shape in activated carbon fabric, a fast intraparticle adsorption kinetics takes place in gas and liquid phase adsorption.
Molecules/atoms of pollutants have an affinity towards activated carbon fabric surface by physical adsorption at low temperatures.
In physical adsorption there is a Van Der Waals interaction, having a long range, but weak forces. Molecules of pollutant bouncing across the activated carbon fabric surface gradually loses its energy and finally comes to rest on it. Due to weak bonds in the physical adsorption molecules can be removed from the activated carbon fabric surface by giving a heat energy. This property is utilised in regenerating activated carbon fabric.
Features of ACF
- It is of minimum 90% pure form of activated carbon
- It is soft and easy to handle
- It has a BET surface area (SBET) of the range from 1,000 to 2,500 m2 g-1 with a high degree of adsorption and desorption characteristics. Effective adsorption is several hundred times higher than that of GAC, PAC or palletized activated carbon.
- ACF is made up of filament yarn, due to which ACF is electrically conductive and hence it can be regenerated by passing a low voltage current across the ACF surface or by heating ACF at 100 oC for 15 to 30 minutes.
- The distribution of pore size is in narrow range > 10 nm.
ACF is used in:
- Air-conditioner filters.
- Air purifying filters.
- Clean rooms.
- All other types of pollution control filters.
- Anti pollution masks – for personal protection against gaseous vapours / fumes and bad odours.
- Refrigerator deodouriser – to arrest odours in refrigerators.
- Cigarette filters – to trap harmful chemicals present in cigarette smoke.