Packed towers crushed packing

When large temperature changes are involved, as in distillation operations, plate towers are often preferred because thermal expansion or contraction of the equipment components may crush the packing. 

Tower packings shall be selected after considering the chemical resistance to scrubbing liquor at the actual operating conditions of maximum temperature and concentration the surface area and void firaction per unit volume when dumped randomly in the towers the expected pressure drop in the tower and the actual crushing strength of the tower packings. 

The former (see Figure 13-5) are loaded into the tower in a completely random manner. Generally, the packings used are made for the purpose at hand. However, on occasions crushed solids (stone, gravel etc.) are used. These materials are not as preferable as those in Figure 13-5 because they give a bed which has poor fluid flow characteristics. 

Packed tower. An air pollution control device in which polluted air is forced upward through a tower packed with crushed rock or wood chips while a liquid is sprayed downward on the packing material. The pollutants in the air stream either dissolve or react chemically with the liquid. 

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