In modern competitive process industry, new plants are being continuously set up and the existing ones are being modified and expanded.  The knowledge of various technical subjects such as thermodynamics, reaction kinetics, unit operations, process design, equipment design etc is a prerequisite to the establishment or development of any process plant. A modern process industry is, in general, more complicated and involves a series of operations which are required to be run continuously, and hence it demands equipment of exceptional robustness, ingenuity and reliability. A variety of equipment is required for processing, handling and storage of process chemicals or ingredients. Each piece of equipment is expected to serve a specific function, although in some cases it can be suitably modified to perform some different function viz. Reaction Vessels, Heat Exchangers, Distillation Columns, Evaporators, Autoclaves, and Storage Tanks etc.