Patent ID: 11933552
Assignee: BASF SE
Field: Chemical engineering (Chemistry)
Classification: CPC F  C | IPC C  F

Claim 0:
1. A method of drying superabsorbent particles comprising heating a drying gas to a temperature in a range from 150 to 400° C. by indirect heat transfer in a heat exchanger for heating gas to a temperature in the range from 150 to 400° C. by indirect heat transfer, wherein all surfaces of walls of the heat exchanger which contact a gas have been hot dip galvanized and then cooled under air to form a zinc-iron diffusion layer and a pure zinc layer on the walls, wherein after the hot dip galvanization and cooling under air, surfaces which contact the gas have been heat treated at a temperature in the range from 400 to 750° C., thereby achieving a zinc coating that remains stable and wherein no Kirkendall effect occurs.