Rotary carbonizer for Activated Carbon Plants
Coconut Shell is used for manufacturing a variety of products of commercial importance including Activated Carbon. Shell is carbonized by using methods like Pit method, Drum method, Destructive Distillation etc. Coconut Shell based Activated Carbon units adopt steam activation process to produce good quality activated carbon.
Activated Carbon is a non-graphic from of carbon totally inert with a porous structure and is microcrystalline in nature which could be produces from any carbonaceous material such as Coal, Lignite, Wood, Paddy Husk, Coir Pith, Coconut Shell Charcoal etc. Activated Carbon manufactured from coconut shell charcoal is considered superior to those obtained from other sources mainly because of small macro-pores structure, which is more effective for the adsorption of gas/vapor and for the removal of colour and ordur of compounds.
The Activated Carbon is extensively used in the refining and bleaching of vegetable oils and chemical solutions, water purification, recovery of solvents and other vapors, recovery of gold, in gas masks for protection against toxic gases, in filter for providing adequate protection against war gases/nuclear fallouts, etc.
Steam activation and chemical activation are the two commonly used process for the manufacture of activated carbon. However, coconut shell based activated carbon units are adopting the steam activation process to produce good quality activated carbon.
The process of activation is carried out in two stages. Firstly, the coconut shell is converted into shell charcoal by carbonization process which is usually carried out in mud pits, brick kilns and metallic portable kilns. The coconut shell charcoal is activated by reaction with steam at a temperature of 900 OC – 1100 OC under controlled atmosphere in rotary kilns. The reaction between steam and charcoal takes place at the internal surface area, creating more sites for adsorption. The temperature factor, in the process of activation is very important. Below 900 OC the reaction becomes too slow and is very uneconomical. Above 1100 OC the reaction becomes diffusion controlled and therefore takes place on the outer surface of the charcoal resulting in loss of charcoal.
In the process of activation of charcoal, the solid carbonaceous fuel is converted in to combustible gases termed as producer gas by partial combustion with limited supply of air and remaining fixed carbon being converted into Activated Carbon by steam.
The manufacture of Activated Carbon divided into three categories as