Membrane systems design process control valves

Reliability takes into account the on-stream factors which can cause unscheduled shut-downs. Membrane systems are extremely reliable with respect to the on-stream factor. The membrane separation process is continuous and few control components can cause a shut-down. Typically, the response to unscheduled shut-downs is rapid for GS whereas PSA systems are moderately reliable owing to the numerous valves associated with the process which can cause unexpected shut-downs. The new PSA are designed with alternative modes of operation, in which 100% of design capacity can be achieved while by-passing any failed valve or instrument, with only a slight recovery loss. Failures are automatically detected and by-passed by the microprocessor-based control system. Flowever, stronger and periodic control cycles are required. The cryogenic process is considered by refiners to be less reliable than PSA or membrane... 

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