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by John T. Small (Author)
This book details a Microsoft Excel spreadsheet which models numerically the following key design factors for horizontal separators and optimizes the vessel dimensions using the Solver add-in, allowing the engineer to minimize the size of the vessel and associated piping whilst achieving satisfactory performance in the separation, process control and safeguarding functions: -Gravity settling zone dimensions for successful phase separation. -Provision of adequate liquid hold up times and height differences between contiguous level control and trip settings.-Type of inlet device, and its impact upon the size of inlet pipework and the dimensions of the separator vessel.-Nozzle sizing according to erosional, velocity head and velocity criteria, and the impact on vessel dimensions.-Maintaining axial velocities of oil and water phases within acceptable limits.-Prevention of re-entrainment of oil droplets into the gas phase.-Prevention of transient gas blowby or gross carryover of liquid during unplanned shutdown.-Provision of adequate liquid and gas holdup volumes for slugging and surging.-Prevention of spurious trips due to foaming, where applicable.The principal calculation method for dimensioning the gravity settling zone of the vessel is based on settling theory, according to which droplets / bubbles of certain diameters settle to their respective continuous phases, however the spreadsheet allows the engineer to concurrently specify minimum allowable oil and / or water retention times if desired.
