Selective adsorption gas separation process

Claim 2

A process according to claim 1 wherein gas is released from the discharge end of said second bed for further cocurrent depressurization thereof during at least part of step (e), said release being terminated before the adsorption front of said one component reaches the second-bed discharge end, and at least part of the so-released gas is discharged as product.

Claim 3

A process according to claim 1 wherein gas is released from the discharge end of said second bed for further cocurrent depressurization thereof during at least part of step (e), said release being terminated before the adsorption front of said one component reaches the second-bed discharge end, one part of the so-released gas being discharged as product and another part of the so-released gas being introduced to the discharge end of another bed containing said one component for purging thereof.

Claim 4

A process according to claim 3 wherein gas is released from the inlet end of said second bed after termination of said further cocurrent depressurization for still further countercurrent depressurization thereof and partial desorption of said one component, and thereafter introducing said one part of one-component-depleted gas from said first bed to the discharge end of the still further depressurized second bed as said purging of step (f).

Claim 5

In an adiabatic process for separating gas mixtures by selectively adsorbing at least one component in an adsorption zone at higher pressure and desorbing the selected component by pressure reduction to a lowest pressure, the improvement comprising the steps of: a. providing three beds of selective adsorbent material each with inlet and discharge ends; b. simultaneously introducing said gas mixture at superatmospheric pressure to the inlet end and introducing one-component-depleted gas initially at said first highest superatmospheric pressure to the discharge end of a first adsorbent bed having previously been cleaned of said one component and initially at lower pressure; c. simultaneously with step (b), releasing gas from the discharge end of a third adsorbent bed initially at substantially said first highest pressure and having previously received said gas mixture at inlet end in sufficient quantity for an adsorption front of said one component to have been formed at said inlet end and progressively moved to a position intermediate said inlet end and said discharge end, flowing one part of the so-released gas to the first-bed discharge end as said one-component-depleted gas and simultaneously discharging another part of said so-released gas as product; d. continuing the gas flows of steps (b) and (c) until the gas pressures in said first and third adsorbent beds are substantially equal, and then terminating the one-component-depleted gas flow from the third bed to the first bed; e. continuing the introduction of said gas mixture to the inlet end of said first bed after the one-component-depleted gas flow termination of step (d) thereby further repressurizing said first bed to said first highest pressure, and releasing gas from the discharge end of said third bed for further cocurrent depressurization thereof during at least part of the gas mixture introduction to said first bed and terminating said release before the one-component-adsorption front reaches the third-bed discharge end and introducing one part of the so-released gas to the discharge end of a second adsorbent bed for purging said onE component at said lowest pressure, and discharging another part of the so-released gas as product gas; f. releasing one-component-depleted gas from the discharge end of the further repressurized first bed, employing one part thereof for partial repressurization of said second adsorbent bed having previously been purged of said one component by introduction to the second-bed discharge end until the gas pressures in said first and second adsorbent beds are substantially equal, and discharging another part of the so-released gas as product; g. releasing additional one-component-depleted gas from the discharge end of the partially depressurized first bed, introducing one part thereof to the third-bed discharge end for purging said one component at said lowest pressure, and discharging another part of the so-released gas as product; h. releasing still additional gas from the inlet end of said first bed for countercurrent depressurization thereof to said lowest pressure and partial desorption of said one component; i. purging said first bed of remaining one component by introducing one-component-depleted gas from said second bed to the discharge end thereof for flow therethrough at said lowest pressure and thereafter consecutively repeating steps (b) through (i); and j. cycling said second and third adsorbent beds consecutively through steps corresponding to the first-bed steps (b) through (i) with the second bed entering the simultaneous gas mixture one-component-depleted gas-introducing of step (b) with the first-bed gas-releasing of step (f) and the third bed entering said simultaneous gas mixture one-component-depleted gas-introducing of step (b) with the first-bed countercurrent depressurizing of step (h).

Claim 6

A process according to claim 6 wherein more one-component-depleted gas is released from the first-bed discharge end after step (g) and before step (h) and introduced to the third-bed discharge end following purging of said one component therefrom, and the flow is continued until the gas pressures in the first and third beds are substantially equal at second equalization pressure lower than the first-second-bed pressure equalization of step (f) and said third bed is partially repressurized; and more one-component-depleted gas is released from the second-bed discharge end after the second-bed step (g) and before second-bed step (h) and introduced to the first-bed discharge end following the first-bed purge step (i) and before first-bed step (b) and the flow is continued until the gas pressures in the first and second beds are substantially equal at said second equalization pressure and said first bed is partially repressurized; and more one-component-depleted gas is released from the third-bed discharge end after the third-bed step (g) and before third-bed step (h) and introduced to the second-bed discharge end during the first-bed further repressurization step (e) and the flow is continued until the gas pressures in the third and second beds are substantially equal at said second equalization pressure and said second bed is partially repressurized.

Claim 7

A process according to claim 7 wherein said gas mixture is air and said selective adsorbent is calcium zeolite A.

Claim 8

In an adiabatic process for separating gas mixtures by selectively adsorbing at least one component in an adsorption zone at higher pressure and desorbing the selected component by pressure reduction to a lowest pressure, the improvement comprising the steps of: a. providing four beds of selective adsorbent material each with inlet and discharge ends; b. simultaneously introducing said gas mixture at superatmospheric pressure to the inlet end and introducing one-component-depleted gas initially at higher than said lowest pressure to the discharge end of a first adsorbent bed having previously been cleaned of said one component and initially at said lowest pressure; c. simultaneously with step (b), releasing gas from the discharge end of a second adsorbent bed Initially at higher than said lowest pressure and having previously received said gas mixture at its inlet end in sufficient quantity for an adsorption front of said one component to have been formed at said inlet end and progressively moved to a position intermediate said inlet end and said discharge end, flowing one part of the so-released gas to the first-bed discharge end as said one-component-depleted gas and simultaneously discharging another part of said so-released gas as product; d. continuing the gas flows of steps (b) and (c) until the gas pressures in said first and second adsorbent beds are substantially equal, and then terminating the one-component-depleted gas flow from the second bed to the first bed; e. continuing the introduction of said gas mixture to the inlet end of said first bed after the one-component-depleted gas flow termination of step (d) thereby further repressurizing said first bed to said first highest pressure, and simultaneously releasing gas from the discharge end of said second bed for further cocurrent depressurization thereof during the feed gas introduction to said first bed and terminating said release at second lower pressure such that the one-component adsorption front is nearer the second-bed discharge end than the intermediate position of step (c), and discharging the so-released gas as product; f. releasing one-component-depleted gas from the discharge end of the further repressurized first bed, employing one part thereof for partial repressurization of a third adsorbent bed initially at said lowest pressure having previously been purged of said one component by introduction to the third-bed discharge end until the gas pressures in said first and third adsorbent beds are substantially equal, and discharging another part of the so-released gas as product; g. releasing additional one-component-depleted gas from the discharge end of the partially depressurized first bed as a first cocurrent depressurization step, and discharging same as product; h. terminating the additional gas releasing of step (g) when the one-component adsorption front is intermediate the inlet and discharge ends and isolating said first bed for a time period; i. releasing still additional one-component-depleted gas from the discharge end of the further depressurized first bed as a second cocurrent depressurization step, and introducing same to the discharge end of said second bed for purging said one component therefrom at said lowest pressure and terminating said releasing when the one-component adsorption front is closer to the discharge end than at the termination (h) but still entirely within said first bed; j. releasing gas from the inlet end of said first bed for countercurrent depressurization thereof to said lowest pressure and partial desorption of said one component; k. purging said first bed of remaining one component by introducing one-component-depleted gas from a third adsorbent bed to the discharge end thereof for flow therethrough at said lowest pressure and thereafter consecutively repeating steps (b) through (k); and l. consecutively cycling said third, fourth and second adsorbent beds through steps corresponding to the first-bed steps (b) through (k) with the third bed entering the simultaneous gas mixture one-component-depleted introducing of step (b) with the first-bed gas releasing of step (f), the fourth bed entering said simultaneously gas mixture one-component-depleted gas-introducing of step (b) with the first-bed isolating of step (h), and the second bed entering said simultaneously gas mixture one-component-depleted gas-introducing of step (b) with the first-bed countercurrent depressurization of step (j).

Claim 9

A process according to claim 9 wherein said gas mixture is air and said selective adsorbent is calcium zeolite A.