Separation Unit Operations Controls
Wayne Seames · 2023
One of the most common tasks in a process is to generate two or more streams out of one or more inlet streams. There are many different unit operations to perform separations. For fluids, these include operations based on vapor–liquid equilibrium such as flash and distillation; those based on solubility such as phase separators, absorption, extraction, and leaching; and those based on physical attraction (adsorption). Multistage distillation is employed in many unit operations and may consist of either a stripping section or, less commonly, a rectifying section or have both. Overhead condensers may be partial or total and bottoms reboilers may be forced or thermosyphon type. Control schemes for the most common configurations are described. Solid-based sorption unit operations typically operate as semi-batch processes with multiple parallel sorption vessels. Typical sequential logic controls are described for both fixed-bed and fluidized-bed systems.