Cryogenic pulverization is a well known method used for the effective comminution of solid materials. However, the economics of this process is doubtful for the processing of flexible polyurethane foam because of the requirement for large amounts of liquid nitrogen coupled with low outputs. This work shows that cryogenic pulverization of flexible polyester polyurethane foam may be performed more efficiently and economically by incorporating an intermediate densification step into the process. Liquid nitrogen usage was reduced from 18 kg per 1 kg of output material to 1 kg per 1 kg of output by including the densification process and by careful optimization of operating parameters. In addition, the output was increased from 15 to 640 kg per h by densifying the foam prior to cryogenic pulverization.
