Bulk powdered carbon was used to de-colourise a final stage product prior to packaging at a bulk chemical manufacturer’s site. The carbon was loaded manually into a holding vessel and after the product batches had been processed the plant personnel had to literally dig out the carbon and clean the vessel which was an extremely dirty and time consuming process. John Morfield process team suggested that this process could be improved and proposed installing a dedicated filter vessel fitted with Zeta carbon cartridges.
Zeta carbon is a family of depth filtration media composed of granulated carbon embedded in a cellulose matrix and assembled into lenticular cartridges.Initial lab scale trials were carried out to establish the correct grade of carbon and the economic viability of introducing this new process. Calculations showed that it would be possible to process 30 batches of the final product through a set of three carbon cells .This was proven after full scale plant trials and a decision to install a permanent filter was taken.
The original cost to purchase the bulk carbon, install, clean out the vessel and disposal was calculated by the customer to be £31,000 per year. Cost to purchase and install the new vessel was a one off cost of £6,000 and consumable costs of the Zeta carbon cells, cleaning and disposal were approximately £18,700 per year giving a cost saving in the first year of £6000.
Subsequent annual savings were in the region of £12,000 however other benefits not used in the calculations were a reduction in product transfer times from 3.5 hours to 1.5 hours and a complete elimination of hazardous operator exposure to dust from the powdered carbon.