Method to separate a gas mixture on a large scale using reversible blowers

Abstract

The present invention provides for a method utilizing horizontal and vertical Adsorber bed(s) with multiple different reversible blower(s) and inputs operating in a vacuum pressure swing adsorption separation process to separate gases. The process is designed to provide a safer and more cost-effective adsorption system on a larger scale that captures and utilizes energy typically wasted during equipment transitions thereby achieving overall higher power efficiency.

Claims

1. An apparatus for producing oxygen comprising: two adsorber beds each connected to two or more flow balanced reversible blowers through isolation valves, an equalization line with an adsorptive buffer vessel, and two product valves; and wherein a control method actuates rotating of said blowers sequentially in clockwise and anticlockwise directions to supply air to the inlet of one bed while regenerating the other bed by removing adsorbed nitrogen using a vacuum.

2. The apparatus of claim 1, further comprising variable drives on each of the reversible blowers.

3. The apparatus of claim 1, with inlet valves located to achieve even flow distribution.

4. The apparatus of claim 1, which has adsorber beds that include two or more blowers where the blowers are configured to operate at different speeds to achieve and even flow distribution.

5. The apparatus of claim 1, further configured to maintain a preset maximum pressure and preset minimum pressure by varying machine speeds and operating at fixed cycle step times.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is the process variation with two horizontal beds each connected to two blowers.

(2) FIG. 2 is the process variation with two horizontal beds each connected to three blowers.

(3) FIG. 3 is a concept of horizontal bed with multiple feed inlets.

(4) FIG. 4 is a concept of vertical bed with multiple feed inlets.

(5) For FIGS. 1-4 please use the following key/legend that describes the characters and acronyms used:

(6) BL-#X Where BL represents a blower, # represents the number of the adsorber bed that the blower is attached to (1, 2 or 3), and X differentiates the two blowers for the same adsorber bed as either A, B or C.

(7) L #X Where L represents the pipe line, # represents the pipe line grouping number (1, 2, 3 or 4), and X represents differentiates the line number to the corresponding blower number (A, B or C).

(8) N #X Where N represents the feed inlets to the adsorber bed, # represents the number of the feed inlet into the bed (1, 2 or 3) and X differentiates the nozzles for the corresponding blower and pipe lines (A or B).

(9) N # Where N represents the feed inlets to the adsorber bed, and # represents the number of feed inlet into the bed (1—any number amount of “X”).

(10) # Where # represents the valve number.

(11) #X Is used to label the valves connecting the beds to the blowers. Where # represents the adsorber bed number and X represents the corresponding blower designation.

DETAILED DESCRIPTION OF THE INVENTION

(12) The present invention provides for an improved VPSA (vacuum pressure swing adsorption) process for separating a gas from a mixture of gases on a larger scale in single or multiple adsorption beds either vertical or horizontal wherein each bed undergoes a process cycle comprising the steps of (1) evacuating the spent bed using two or more parallel blowers being used to generate vacuum; (2) purging the spent bed using the vacuum and a slip stream of product gas from the producing bed; (3) feeding the mixture of gases to the producing bed with two or more blowers running in opposite direction with respect to the blowers running to generate vacuum on the spent bed; (4) producing purified product gas from the producing bed; and (5) pressure equalizing the two beds, concurrently changing directions on all the blowers.

(13) The present inventors anticipate two horizontal or vertical beds in the process as shown in FIG. 1 and FIG. 2. There will be two or more reversible blowers attached to each of the beds. The reversible blowers are connected to their individual motors. The connection of the blowers to the beds is made to minimize the flow variation across the bottom section of the bed. The inventors also anticipate running two or more connected blowers to the beds at different speeds in order to achieve best possible flow distribution across each of the beds. It is also anticipated that each of the beds may be operated as a single bed process using the adsorptive buffer.

(14) The process described in FIG. 1 is as followed. The Blowers “BL-1A” and “BL-1B” get the feed gas and rejects waste through line “L1A” and “L1B” respectively. In the present inventions' embodiment this feed gas is Air and waste is Nitrogen rich gas. The feed gas from “BL-1A” and “BL-1B” are fed to the “ADSORBER BED 1” through lines “L3A” and “L3B” and valves “1A” and “1B”. The purified gas product which is oxygen (O2) in the present embodiment is obtained from the product side of “ADSORBER BED 1”. The gas product is withdrawn from the process through line “L5” and valve “3” and line “L8”. During purge and equalization steps the product gas will be diverted to the “ADSORPTIVE BUFFER” through the valves “6” and line “L9”. Also during the regeneration part of the cycle the purge gas will be received from tank “ADSORPTIVE BUFFER” through valve “7” and line “L6” from “ADSORBER BED 2”.

(15) The Blowers “BL-2A” and “BL-2B” get the feed gas and rejects waste through line “L2A” and “L2B” respectively. In the present inventions' embodiment this feed gas is Air and waste is Nitrogen rich gas. The feed gas from “BL-2A” and “BL-2B” are fed to the adsorber bed “ADSORBER BED 2” through lines “L4A” and “L4B” and valves “2A” and “2B”. The purified gas product which is oxygen (O2) in the present embodiment is obtained from the product side of “ADSORBER BED 2”. The gas product is withdrawn from the process through line “L7” and valve “5” and line “L8”. During purge and equalization steps the product gas will be diverted to the equalization tank “ADSORPTIVE BUFFER” through the valves “7” and line “L6”. Also during the regeneration part of the cycle the purge gas will be received from tank “ADSORPTIVE BUFFER” through valve “6” and line “L9” from “ADSORBER BED 1”.

(16) The present invention provides that the claimed process can be operated in a nominal full cycle timing 20 seconds to 300 seconds, most preferably between 30 seconds and 120 seconds.

(17) The process includes an optional product buffer tank which may be beneficial to achieve better mixing and more uniform product purity and pressure.

(18) The present invention required the process to be operated at a typical maximum feed pressure of between 12 psia to 30 psia, most preferably between 8 psia and 5 psia. The minimum pressure in the process is also preset with a controller and can be controlled either by changing the speed of blowers or the cycle step times.

(19) While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modifications of the invention will be obvious to those skilled in the art. The appended claims and this invention generally should be construed to cover all such obvious forms and modifications which are within the true spirit and scope of the present invention.