Process for reducing emissions from industrial sterilizers

Claim 2

A process for treating a gas mixture including a sterilant gas and a diluent gas, comprising: (a) feeding said gas mixture to a first separation process to substantially remove said sterilant from said gas mixture; (b) withdrawing a treated gas stream from said first separation process; (c) feeding said treated gas stream to a second separation process, comprising passing at least a portion of said treated gas stream through a membrane separation unit containing a permselective membrane; (d) withdrawing from said separation unit a first stream enriched in said diluent gas compared with said gas mixture; (e) withdrawing from said membrane separation process a second stream depleted in said diluent gas compared with said gas mixture.

Claim 3

The process of claim 1, wherein said first separation process is a scrubbing process.

Claim 4

The process of claim 1, wherein said first separation process is an oxidation process.

Claim 5

The process of claim 1, wherein said first separation process is an ion-exchange process.

Claim 6

The process of claim 1, wherein said first separation process is a condensation process.

Claim 7

The process of claim 1, wherein said first stream is a permeate stream from said membrane separation unit.

Claim 8

The process of claim 1, wherein said first stream is a residue stream from said membrane separation unit.

Claim 9

The process of claim 1, wherein said permselective membrane comprises a multilayer membrane.

Claim 10

The process of claim 1, wherein said permselective membrane comprises a rubbery polymer.

Claim 11

The process of claim 1, wherein said permselective membrane comprises silicone rubber.

Claim 12

The process of claim 1, wherein said gas mixture includes nitrogen and wherein said permselective membrane has a diluent gas/nitrogen selectivity not less than 5.

Claim 13

The process of claim 1, wherein said diluent gas comprises a fluorinated hydrocarbon.

Claim 14

The process of claim 1, wherein said diluent gas is CFC-12.

Claim 15

The process of claim 1, wherein said sterilant gas is ethylene oxide or propylene oxide.

Claim 16

The process of claim 1, wherein at least 85% of said diluent gas component is removed from said treated gas stream.

Claim 17

The process of claim 1, wherein at least 90% of said diluent gas component is removed from said treated gas stream.

Claim 18

A process for treating a gas mixture including a sterilant gas and a diluent gas, comprising: (a) feeding said gas mixture to a first separation process to substantially remove said sterilant from said gas mixture; (b) withdrawing a treated gas stream from said first separation process; (c) feeding said treated gas stream to a second separation process, comprising a condensation step and a membrane separation step, said condensation step comprising bringing said treated gas stream to a condition characterized in that the concentration of said diluent gas is greater than its saturation concentration at said condition, so that a portion of said diluent gas condenses from said treated gas stream; and said membrane separation step comprising: (a) passing at least a portion of said treated gas stream through a membrane separation unit containing a permselective membrane; (b) withdrawing from said separation unit a first stream enriched in said diluent gas compared with said gas mixture; (c) withdrawing from said membrane separation process a second stream depleted in said diluent gas compared with said gas mixture.

Claim 19

A process for treating a gas mixture including a sterilant gas and a diluent gas, comprising: (a) feeding said gas mixture to a first separation process to substantially remove said sterilant from said gas mixture; (b) withdrawing a treated gas stream from said first separation process; (c) feeding said treated gas stream to a second separation process, comprising a condensation step and a membrane separation step, said condensation step comprising bringing said treated gas stream to a condition characterized in that the concentration of said diluent gas is greater than its saturation concentration at said condition, so that a portion of said diluent gas condenses from said treated gas stream; and said membrane separation step comprising: (a) passing at least a portion of said treated gas stream through a membrane separation unit containing a permselective membrane; (b) withdrawing from said separation unit a first stream enriched in said diluent gas compared with said gas mixture; (c) withdrawing from said membrane separation process a second stream depleted in said diluent gas compared with said gas mixture.

Claim 20

The process of claim 17, wherein said condensation step precedes said membrane separation step.

Claim 21

The process of claim 17, wherein said condensation step follows said membrane separation step.

Claim 22

The process of claim 17, wherein said condensation step includes a compression step to raise the pressure of said treated gas stream and a chilling step to lower the temperature of said treated gas stream.

Claim 23

The process of claim 17, wherein said first separation process is a scrubbing process.

Claim 24

The process of claim 17, wherein said first separation process is an oxidation process.

Claim 25

The process of claim 17, wherein said first separation process is an ionexchange process.

Claim 26

The process of claim 17, wherein said first separation process is a condensation process.

Claim 27

The process of claim 17, wherein said first stream is a permeate stream from said membrane separation unit.

Claim 28

The process of claim 17, wherein said first stream is a residue stream from said membrane separation unit.

Claim 29

The process of claim 17, wherein said permselective membrane comprises a multilayer membrane.

Claim 30

The process of claim 17, wherein said permselective membrane comprises a rubbery polymer.

Claim 31

The process of claim 17, wherein said permselective membrane comprises silicone rubber.

Claim 32

The process of claim 17, wherein said gas mixture includes nitrogen and wherein said permselective membrane has a diluent gas/nitrogen selectivity not less than 5.

Claim 33

The process of claim 17, wherein said diluent gas comprises a fluorinated hydrocarbon.

Claim 34

The process of claim 17, wherein said diluent gas is CFC-12.

Claim 35

The process of claim 17, wherein said sterilant gas is ethylene oxide or propylene oxide.

Claim 36

The process of claim 17, wherein at least 85% of said diluent gas component is removed from said treated gas stream.

Claim 37

The process of claim 17, wherein at least 90% of said diluent gas component is removed from said treated gas stream.

Claim 38

The process of claim 17, wherein said compression step does not raise the pressure of said incoming gas stream above 15 atmospheres.