초록

A pressure swing adsorption process for an adsorption system having 12 adsorption beds, the process having a cycle with 5 pressure equalization steps. Background is provided for the various pressure swing adsorption cycle steps.

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1. A process for separating a primary gas component from a feed gas mixture comprising the primary gas component and secondary gas components in a plurality of twelve adsorption beds, each adsorption bed containing an adsorbent selective for the secondary gas components, the process comprising subje

1. A process for separating a primary gas component from a feed gas mixture comprising the primary gas component and secondary gas components in a plurality of twelve adsorption beds, each adsorption bed containing an adsorbent selective for the secondary gas components, the process comprising subjecting each of the plurality of adsorption beds to at least one of a first repetitive cycle and a second repetitive cycle, the first repetitive cycle comprising, in sequence, (a) a production step or hybrid step thereof, (b) a plurality of five depressurizing equalization steps, (c) a supply purge gas step, (d) a blowdown step, (e) a purge step, (f) a plurality of five pressurizing equalization steps, and (g) a repressurization step, and the second repetitive cycle comprising, in sequence, (a) a production step or hybrid step thereof, (b) a plurality of five depressurizing equalization steps, (c/d) a hybrid supply purge gas/blowdown step, (e) a purge step, (f) a plurality of five pressurizing equalization steps, and (g) a repressurization step; wherein no effluent from the blowdown step and no effluent from the purge step is recycled to the plurality of twelve adsorption beds as rinse gas;wherein the plurality of five depressurizing equalization steps (b) comprises, in sequence, a first depressurizing equalization step, a second depressurizing equalization step, a third depressurizing equalization step, a fourth depressurizing equalization step, and a fifth pressure decreasing equalization step;wherein the plurality of five pressurizing equalization steps (f) comprises, in sequence, a fifth pressurizing equalization step, a fourth pressurizing equalization step, a third pressurizing equalization step, a second pressurizing equalization step, and a first pressurizing equalization step;wherein the fifth depressurizing equalization step comprises co-currently withdrawing an effluent gas from an adsorption bed undergoing the fifth depressurizing equalization step, and passing at least a portion of the effluent gas from the adsorption bed undergoing the fifth depressurizing equalization step as pressure equalization gas to an adsorption bed undergoing the fifth pressurizing equalization step thereby equalizing the pressure between the adsorption bed undergoing the fifth depressurizing equalization step and the adsorption bed undergoing the fifth pressurizing equalization step; andwherein the purge step (e) comprises counter-currently introducing the purge gas from the adsorption bed undergoing the fifth depressurizing equalization step into the adsorption bed undergoing the purge step and the fifth depressurizing equalization step further comprises passing a second portion of the effluent gas from the adsorption bed undergoing the fifth depressurizing equalization step to at least one of the adsorption beds undergoing the purge step as the purge gas. 2. The process of claim 1 wherein: the first repetitive cycle has a cycle time to execute one complete cycle of the first repetitive cycle and the second repetitive cycle has a cycle time to execute one complete cycle of the second repetitive cycle;the production step or hybrid step thereof (a) comprises introducing the feed gas mixture at a feed gas pressure ranging from 1.0 MPa to 7.0 MPa into an adsorption bed undergoing the production step or hybrid step thereof and adsorbing the secondary gas components on the adsorbent in the adsorption bed undergoing the production step or hybrid step thereof while simultaneously withdrawing a product gas from the adsorption bed undergoing the production step or hybrid step thereof;the first depressurizing equalization step comprises co-currently withdrawing a pressure equalization gas from an adsorption bed undergoing the first depressurizing equalization step, and passing the pressure equalization gas to an adsorption bed undergoing a first pressurizing equalization step thereby equalizing the pressure between the adsorption bed undergoing the first depressurizing equalization step and the adsorption bed undergoing the first pressurizing equalization step;the second depressurizing equalization step comprises co-currently withdrawing a pressure equalization gas from an adsorption bed undergoing the second depressurizing equalization step, and passing the pressure equalization gas from the adsorption bed undergoing the second depressurizing equalization step to an adsorption bed undergoing a second pressurizing equalization step thereby equalizing the pressure between the adsorption bed undergoing the second depressurizing equalization step and the adsorption bed undergoing the second pressurizing equalization step;the third depressurizing equalization step comprises co-currently withdrawing a pressure equalization gas from an adsorption bed undergoing the third depressurizing equalization step, and passing the pressure equalization gas from the adsorption bed undergoing the third depressurizing equalization step to an adsorption bed undergoing a third pressurizing equalization step thereby equalizing the pressure between the adsorption bed undergoing the third depressurizing equalization step and the adsorption bed undergoing the third pressurizing equalization step;the fourth depressurizing equalization step comprises co-currently withdrawing a pressure equalization gas from an adsorption bed undergoing the fourth depressurizing equalization step, and passing the pressure equalization gas from the adsorption bed undergoing the fourth depressurizing equalization step to an adsorption bed undergoing a fourth pressurizing equalization step thereby equalizing the pressure between the adsorption bed undergoing the fourth depressurizing equalization step and the adsorption bed undergoing the fourth pressurizing equalization step;the supply purge gas step (c) comprises co-currently withdrawing a purge gas from an adsorption bed undergoing the supply purge step, and passing the purge gas from the adsorption bed undergoing the supply purge step to the adsorption beds undergoing the purge step;the blowdown step (d) comprises counter-currently withdrawing a blowdown gas from an adsorption bed undergoing the blowdown step, the blowdown gas having a concentration of the primary gas component that is lower than the concentration of the primary gas component in the feed gas mixture;the hybrid supply purge gas/blowdown step (c/d) comprises co-currently withdrawing a purge gas from an adsorption bed undergoing the hybrid supply purge gas/blowdown step, and passing the purge gas from the adsorption bed undergoing the hybrid supply purge gas/blowdown step to an adsorption bed undergoing the purge step while simultaneously counter-currently withdrawing a blowdown gas from the adsorption bed undergoing the hybrid supply purge gas/blowdown step, the blowdown gas having a concentration of the primary gas component that is lower than the concentration of the primary gas component in the feed gas mixture;the purge step (e) further comprises counter-currently introducing at least one of (i) the purge gas from the adsorption bed undergoing the supply purge step, and (ii) the purge gas from the hybrid supply purge gas/blowdown step into an adsorption bed undergoing the purge step and counter-currently withdrawing a purge gas effluent from the adsorption bed undergoing the purge step, the purge gas effluent having a concentration of the secondary gas components that is higher than the concentration of the secondary gas components in the feed gas mixture;the first pressurizing equalization step comprises counter-currently introducing the pressure equalization gas from the adsorption bed undergoing the first depressurizing equalization step into the adsorption bed undergoing the first pressurizing equalization step;the second pressurizing equalization step comprises counter-currently introducing the pressure equalization gas from the adsorption bed undergoing the second depressurizing equalization step into the adsorption bed undergoing the second pressurizing equalization step;the third pressurizing equalization step comprises counter-currently introducing the pressure equalization gas from the adsorption bed undergoing the third depressurizing equalization step into the adsorption bed undergoing the third pressurizing equalization step;the fourth pressurizing equalization step comprises counter-currently introducing the pressure equalization gas from the adsorption bed undergoing the fourth depressurizing equalization step into the adsorption bed undergoing the fourth pressurizing equalization step; andthe fifth pressurizing equalization step comprises counter-currently introducing the pressure equalization gas from the adsorption bed undergoing the fifth depressurizing equalization step into the adsorption bed undergoing the fifth pressurizing equalization step; andthe repressurization step (g) comprises increasing the pressure in an adsorption bed undergoing the repressurization step until the adsorption bed undergoing the repressurization step is substantially at the feed gas pressure, by at least one of (g1) co-currently introducing the feed gas mixture into the adsorption bed undergoing the repressurization step, and (g2) counter-currently introducing a portion of the product gas from the adsorption bed undergoing the production step into the adsorption bed undergoing the repressurization step;wherein the fifth depressurizing equalization step comprises passing a second portion of the effluent gas from the adsorption bed undergoing the fifth depressurizing equalization step to at least one of the adsorption beds undergoing the purge step as the purge gas from the adsorption bed undergoing the fifth depressurizing equalization step when the purge step comprises counter-currently introducing the purge gas from the adsorption bed undergoing the fifth depressurizing equalization step. 3. The process of claim 1 wherein: (i) the duration of the production step is 23% to 27% of the cycle time of the first repetitive cycle or the duration of the purge step is 23% to 27% of the cycle time of the first repetitive cycle when the adsorption beds are subjected to the first repetitive cycle; and(ii) the duration of the purge step is 23% to 27% of the cycle time of the second repetitive cycle when the adsorption beds are subjected to the second repetitive cycle. 4. The process of claim 1 wherein the primary gas component is H2 and the secondary gas components comprise at least two of CO, CO2, CH4, and N2. 5. The process of claim 1 wherein the first pressurizing equalization step further comprises at least one of (i) co-currently introducing the feed gas mixture into the adsorption bed undergoing the first pressurizing equalization step simultaneous with the counter-current introduction of the pressure equalization gas from the adsorption bed undergoing the first depressurizing equalization bed, and (ii) counter-currently introducing product gas from at least one of the adsorption beds undergoing the feed step into the adsorption bed undergoing the first pressurizing equalization step simultaneous with the counter-current introduction of the pressure equalization gas from the adsorption bed undergoing the first depressurizing equalization bed. 6. The process of claim 1 wherein the process comprises subjecting each of the plurality of adsorption beds to the first repetitive cycle. 7. The process of claim 6 wherein the first repetitive cycle further comprises an idle step between the fifth depressurizing equalization step of the plurality of five depressurizing equalization steps and the supply purge gas step. 8. The process of claim 1 wherein the process comprises subjecting each of the plurality of adsorption beds to the second repetitive cycle. 9. The process of claim 8 wherein the second repetitive cycle further comprises an idle step between the fifth depressurizing equalization step of the plurality of five depressurizing equalization steps and the hybrid supply purge gas/blowdown step. 10. The process of claim 1 wherein at least one of the plurality of five depressurizing equalization steps is a parallel depressurizing equalization step and at least one of the plurality of five pressurizing equalization steps is a parallel pressurizing equalization step. 11. The process of claim 1 wherein at least one of the plurality of five pressurizing equalization steps is a hybrid pressurizing equalization/feed pressurization step. 12. The process of claim 1 wherein at least one of the plurality of five pressurizing equalization steps is a hybrid pressurizing equalization/product pressurization step.