The active component in the HYDECAT™ catalysts is nickel dispersed and fixed to a highly porous ceramic support to achieve high activity and stability under the highly alkaline conditions. The process decomposes sodium hypochlorite into brine and oxygen gas by the following reaction:
2NaOCl -> 2NaCl + O2
Catalyst surface effect
The hypochlorite ion is adsorbed onto the catalyst surface where it is broken down to give a chloride ion with the oxygen atom remaining on the catalyst surface. Because of the potential for competition for active sites, the complete composition of the effluent stream needs to be characterised to allow optimum design (ions such as hydroxide and carbonate will not react on the catalyst surface but will chelate and diffuse in competition with the hypochlorite ion and thus block active nickel sites).
Catalyst surface reaction
The oxygen atom on the catalyst surface can combine with an adjacent oxygen atom to form an oxygen molecule, which is vented to the atmosphere. There is the potential for reaction with another molecule other than a second oxygen atom, such as a volatile organic compound (VOC). Thus the total VOC content of the final effluent can also be lowered, reducing its chemical oxygen demand (COD).
The reaction products occur naturally and the catalyst itself can be recycled when exhausted. Therefore, adopting the HYDECAT process will improve the environmental performance of any industrial process using or producing chlorine.
The flexibility of the process allows easy retrofitting to existing plants. It is robust and requires little monitoring or maintenance and provides a simple, efficient and effective means of environmental compliance.
The configuration and the positioning of the HYDECAT vessel can be designed to replace or complement existing systems and so achieve the most economical effluent treatment solution for the customer.