Optimizing Steam Activation for Activated Carbon manufacturing
Well if you are manufacturing activated carbon from Steam, you would not wish to miss the following checkpoints to ensure a good surface characteristic of the activated carbon produced from the rotary kiln. When I say good surface – I mean a good degree of Mesoporsity and Macroporosity .
Optimised Rotation Speed and Slant of Rotary Kiln – To ensure the raw material gets enough time to carbonize and have the steam create a porous structure, residence time is very important. A very fast rotation speed of the rotary kiln or an excessive slant will cause the material to be pushed faster thereby producing a lesser degree of activation which in turn affects the porosity. However a high residence time cause the material to char or turn into ash and thereby reducing the yield and activation of the furnace. A 200 – 350 second residence time depending on other characteristics is normally acceptable.
Reaction Temperature – 850 degrees centigrade is the optimum temperature for a great pore structure and good yield.
Steam Characteristics – Since the H20 from the steam causes to Carbon to react and create an exothermic reaction, the quality of steam is critical to activation. Higher moisture content will cause the furnace temperature to reduce and thereby reduced activation, however very high temperatures will cause the material to char.
Raw Material – Selection of raw material might be the most important factor in steam activation. Highly carbonised Pine Charcoal or High carbon content raw material will yield into a high degree of meso porosity. Soft wood will yield into meso porosity and hard woods yield into micro porosity. Other factors like Rotary Kiln Diameters and Length, Air Speed, Outside temperature, feeding rate and insulation have an impact on the quality and yield of activated carbon produced from steam activation.
All the above factors are subjective to size, dimension of machinery , raw material quality and ambient conditions.