Process simulation is built or reused for the unit operation under investigation for the possible capacity increase.
Actual plant operating data is matched in the process simulation model. In the validated model, the capacity is increased and all equipment, unit operations, utilities, piping and valves in the affected plant or unit operations is reviewed.
The items which have no limitations are retained as it is but affected equipment and units operations (vessels, pumps, compressors, distillation column, control valves, etc) are checked for possible minor change to accommodate (even design margins are altered). Else equipment is resized for anticipated fluids rate, pressure, temperature, etc. Possible modifications or alterations are identified and changes are implemented with expert advice.