Equipment Sizing

EQUIPMENT SIZING, SELECTION AND SPECIFICATION

The equipment used in the chemical processes industries can be divided into two classes:

i. Proprietary

Proprietary equipment is designed by the manufacturer to meet performance specifications made by the user; these specifications may be regarded as the process design of the equipment. This category includes equipment with moving parts such as pumps, compressors, and drivers as well as cooling towers, dryers, filters, mixers, piping equipment, valves, and the structural aspects of heat exchangers, furnaces, and other equipment.

ii. Non-proprietary (custom-designed)

Non-proprietary equipment is designed as special, one-off, items for particular processes; for example, reactors, distillation columns and heat exchangers. They are not amenable to complete standardization.

Proprietary equipment is provided “off the shelf’’ in limited sizes and capacities. Special sizes that would fit particular applications more closely often are more expensive than a larger standard size that incidentally may provide a worthwhile safety factor. Even largely custom designed equipment, such as vessels, is subject to standardization such as discrete ranges of head diameters, pressure ratings of nozzles, sizes of man-ways, and kinds of trays and packing. Many codes and standards are established by government agencies, insurance companies, and organizations sponsored by engineering societies such as Tubular Exchangers Manufacturers’ Association (TEMA), American Institute of Chemical Engineers, Instrumentation, Systems and Automation Society (ISA), National Institute of Standards and Technology (NIST), American Petroleum Institute , (API).

Equipment sizing is the calculation of all physical attributes that allow unique costing of the unit. It entails computations on capacity, height, cross-sectional area, pressure rating.

MATERIAL SELECTION PROCESS

In selecting metals and alloys as materials of construction, one must have knowledge of...