Phenolic foam is known as "the king of heat preservation", which was used in the insulation of missiles and rocket heads early. In recent years, due to high building, transportation, ship, aviation, space technology and other aspects of synthetic foam plastics, thermal stability and fire resistance have been put forward strict requirements, so that phenolic foam has developed more rapidly. As a new type of multi-purpose foam material, phenolic resin foam has attracted wide attention due to its advantages such as heat resistance, flame resistance, self extinguishing, flame resistance penetration, and no drop in fire.
Drying can be divided into two categories, one requires that after drying, raw materials remain the original shape, such as many kinds of food drying, building materials drying, etc. The other is to dry liquid, muddy, massive and powdery materials into powdery or granular products. Some drying processes, especially the drying of drugs, hope not to destroy the original crystal shape. In pharmaceutical production, liquid and powder materials are often used to reach a certain size of particles after drying. There are also technical problems in the feeding and discharging of dryers, and many aspects still need to rely on practical experience. From the economic point of view, the size of the treatment capacity is also one of the factors to choose the type of drying equipment.