Environmental Concerns and Hygiene

In any solids-processing operation, dust control is an important consideration. Where the solid product is conveyed from the apparatus, as with an air mill, highly efficient particle collection is necessary. Combinations of cyclones and bag collectors are often used in this application. Even when recovery is uneconomic, bag collectors may be used to prevent the nuisance of dust release. Other apparatus that does not recover the solids in an immediately useful form may also be used. This category includes wet scrubbers (e.g., venturis and various scrubbing columns) and electrostatic precipitators. 

Dryers and some size reduction systems release solvents from the apparatus. With the possible exception of water, these solvents must not be allowed to escape into the environment. In most cases, the bulk of the evaporated 

Many plants produce a variety of products and will frequently change from one to another. The loss of product and auxiliary materials should be minimized in these cases. Chapter 5 treats the subject of process changeover in detail. 

---