“Self-Sustained Integrated Closed Cycle Coconut Shell Activated carbon Production Process”

A prototype of the proposed process has been developed in the mechanical department laboratory under a start-up scheme of IIT Madras. This process consists of a fixed bed reactor where coconut shells are loaded, burned and converted into activated carbon, in the presence of super heated steam and air under controlled operating conditions. The super heated steam is generated from a steam generator (powered by a clean combustion burner) and is fed into the reactor via multiple injection ports. Air is sucked into the reactor using the blower, operated under controlled condition using Variable frequency Drive. The system is designed, engineered and operated in such a fashion that the optimal activation time and temperature is maintained to produce commercially acceptable activated carbon. Activated carbon is removed from the bottom of the reactor using the screw conveyor and is collected in the collecting drum. The combustible gases coming out of the reactor is cleaned and cooled in a scrubber unit and is then burned using a clean combustion burner and the combusted gas is passed into the steam generator.

The quality of the activated carbon is tested through the Iodine Number test based on the ASTM standard ‘ASTM D4607’. The activated carbon produced from the prototype is of acceptable market quality with an iodine number of 900 mg/g, which is higher than the market requirement of 500 mg/g or above. It yields 110 g per kg of biomass that is 11% activated carbon..The process parameters of the system can also be customized for a wide range of Iodine number according to market demand.

The novelty of this production process is the production of activated carbon in a fixed bed reactor, directly from coconut shells without it being converted to an intermediate product (charcoal) as it is done in the traditional method. Moreover, the system doesn’t use any external heat source (diesel). The Process control of the system is optimized as a result of applied research in the ‘Thermochemical’ Biomass conversion and the process control of the system is patent-able and currently in progress.


Posted on

April 23, 2019

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