Chill rolls

BACKGROUND
Chill rolls are often cooled with roughly-cleaned sea or river water. After a time, this will cause deposits and clogging of the cooling system, which results in reduced cooling capacity, and lower production capacity. The customer had problems with a cooling system in a coating roll in a papermaking machine. Cooling was ineffective and the coating turned out uneven, resulting in major loss in production. Replacing the roll would mean a shut down for about two days for the whole production line. Alternatively, the roll was left in place while a CIP-cleaning (Cleaning In Place) was carried out and at the same time, paper was procuced in another production line.
RESULTS
The cost of the reconditioning was approx. EUR 10.000, compared to the estimated saving from this operation, approx. EUR 320.000, which corresponds to lost production during change of roll. Furthermore, it is estimated that it would have cost about EUR 8.500 per hour if the production had stood idle for two days while changing a roll.
DESCRIPTION OF APPLICATION
Sector:
Pulp & Paper
Application:
Cleaning of chill rolls
Deposit:
Rust, limescale and humus