Membrane unit turn-down control system
AssigneeAir Products and Chemicals, Inc.
InventorsStephen P. DiMartino, Sr., Jeffrey A. Hopkins, Ruth A. Davis
Life of this patent
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Abstract
A permeator system for separating at least one gaseous component from a feed gas mixture containing at least one other component using a semi-permeable membrane is disclosed which maintains high permeate product purity and desired component recovery during periods of turn-down in capacity. In accordance with the present invention, the permeator system contains a series of flow and pressure sensors and valves which regulate differential pressure across the membrane based upon permeate product demand or feed availability.
Claims22
In a process for separating a component of feed gas mixture containing at least one other component by passing said feed gas to a membrane unit containing a semi-permeable membrane such that one component is separated by preferential permeation through said membrane and is subsequently removed or recovered from the membrane unit as permeate product through a permeate gas outlet while non-permeating components are removed as residual gas through a reject gas outlet, the improvement for maintaining high permeate product purity during periods of turn-down in feed flow capacity which comprises:
- (a) maintaining a substantially constant permeate backpressure in said permeate gas outlet;
- and
- (b) maintaining the flow of residual gas through said reject gas outlet at a substantially constant value.
A permeator system for separating at least one gaseous component from a feed gas mixture containing at least one other component, said system comprising:
- a membrane unit comprising at least one semi-permeable membrane which is more permeable to one component in said feed gas mixture than to at least one other component, said semi-permeable membrane having a reject side and a permeate side;
- a feed inlet in fluid communication with the membrane unit, positioned such that said feed gas mixture can be passed through said feed inlet to contact the reject side of said semi-permeable membrane;
- a reject gas outlet in fluid communication with said membrane unit positioned such that gas which does not permeate through the semi-permeable membrane can be removed from the membrane unit via said reject gas outlet;
- a volumetric flow valve positioned along said reject gas outlet to control the flow of reject gas through said reject gas outlet;
- a flow controller positioned along said reject gas outlet which measures the volumetric flow of gas through said reject gas outlet, and controls said volumetric flow valve to regulate the gas flow through said reject outlet;
- a permeate gas outlet in fluid communication with the membrane unit, positioned such that the portion of said feed gas which permeates through the semi-permeable membrane can be removed form the membrane unit;
- a permeate valve means, positioned along said permeate gas outlet to control permeate backpressure and;
- a pressure controller positioned along said permeate gas outlet which measures the pressure in the permeate gas outlet upstream of said permeate valve means, and controls said permeate valve means.
Dependencies are inferred from the claim text.