Separation process and apparatus for light noble gas

Patent metadata

Field	Value
Publication number	US-10843121-B2
Application number	US-201916251594-A
Country	US
Kind code	B2
Filing date	Jan 18, 2019
Priority date	Dec 21, 2017
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

Process and apparatus for producing helium, neon, or argon product gas using an adsorption separation unit having minimal dead end volumes. A purification unit receives a stream enriched in helium, neon, or argon, and a stream is recycled from the purification unit back to the adsorption separation unit in a controlled manner to maintain the concentration of the helium, neon, or argon in the feed to the separation unit within a targeted range.

First claim

We claim:

1. An apparatus for producing a light noble gas-rich product stream from a feed gas comprising a light noble gas and at least one other gaseous component, the light noble gas selected from the group consisting of helium and neon, the apparatus comprising:
a feed membrane separation unit having an inlet for receiving a feed gas stream, a permeate outlet, and a non-permeate outlet;
an adsorption separation unit, wherein the adsorption separation unit comprises a plurality of vessels each containing a bed of adsorbent;
a feed gas header in selective fluid communication with each of the plurality of vessels;
a product gas header in selective fluid communication with each of the plurality of vessels;
a tail gas header in selective fluid communication with each of the plurality of vessels;
process gas transfer lines operatively connecting the plurality of vessels to the feed gas header, the product gas header, and the tail gas header;
each vessel of the plurality of vessels having process gas transfer lines associated therewith;
a plurality of valves in the process gas transfer lines including a plurality of valves adjacent and associated with each respective vessel;
wherein the adsorption separation unit has a central volume of process gas transfer lines associated with each of the respective vessels, Vc;
wherein the central volume for each respective vessel is the sum of
(i) the volume contained in the process gas transfer lines associated with the respective vessel connecting the respective vessel to each valve adjacent the respective vessel,
(ii) all dead-end volumes, if any, connected at a junction to the respective vessel, and
(iii) all dead-end volumes, if any, connected at a junction to any of the process gas transfer lines associated with the respective vessel that connect the respective vessel to any valve adjacent to the respective vessel;
wherein the central volume for each respective vessel includes a secondary volume, V 2 , where the secondary volume is the sum of
(i) the volume of all dead-end volumes, if any, connected to the respective vessel;
(ii) the volume of all dead-end volumes, if any, connected at a junction to any of the process gas transfer lines associated with the respective vessel that connect the respective vessel to any valve adjacent the respective vessel, and
(iii) the volume of any process gas transfer lines, if any, having a first end terminating in a valve adjacent the respective vessel that is configured to permit transfer of process gas to the tail gas header when open and having a second end terminating at a junction to any other of the associated process gas transfer lines that connect the respective vessel to any other valve adjacent to the respective vessel;
wherein the secondary volume V 2 is less than 5% of the central volume Vc for each vessel; and
a conduit system for transferring a permeate stream from the permeate outlet to the feed gas header of the adsorption separation unit.

2. The apparatus according to claim 1 further comprising:
a purification unit, the purification unit having an inlet, a first outlet, and a second outlet, the inlet in fluid communication with the product gas header of the adsorption separation unit;
wherein the conduit system comprises a gas mixer having a first inlet for receiving the permeate stream, a second inlet in fluid communication with a source of a second gas having a higher light noble gas concentration than the permeate gas, and an outlet in fluid communication with a combined gas stream, wherein the feed gas header of the adsorption separation unit is in downstream fluid communication with the outlet of the gas mixer;
a sensor in at least one of (i) a feed gas line supplying the inlet of the feed membrane separation unit, (ii) a permeate stream line connecting the permeate outlet of the feed membrane separation unit to the first inlet of the gas mixer, (iii) a combined gas stream line connecting the outlet of the gas mixer to the feed gas header of the adsorption separation unit, and (iv) the feed gas header; and
a controller in signal communication with the sensor, the controller operable to control the flow rate of light noble gas from the source of the second gas to the second inlet of the gas mixer responsive to signals from the sensor.

3. The apparatus according to claim 2 wherein the source of the second gas comprises the first outlet of the purification unit.

4. The apparatus according to claim 2 wherein the source of the second gas comprises the second outlet of the purification unit.

5. The apparatus according to claim 2 wherein the source of the second gas comprises a process gas transfer line which operatively connects the product gas header to the inlet to the purification unit.

6. The apparatus according to claim 2 wherein the gas mixer has a third inlet in fluid communication with the second outlet of the purification unit.

7. The apparatus according to claim 2 wherein the gas mixer has a third inlet in fluid communication with a process gas transfer line which operatively connects the product gas header of the adsorption separation unit to the inlet to the purification unit.

8. The apparatus according to claim 2 wherein the purification unit is a membrane-type separation unit,
wherein the source of the second gas comprises the first outlet of the purification unit; and
wherein at least one of
(a) the purification unit comprises one or more adjustable orifices in signal communication with the controller, the one or more adjustable orifices operative to control a pressure in the purification unit; and
the controller is operable to control the flow rate of light noble gas from the source of the second gas to the second inlet of the gas mixer by adjusting the one or more adjustable orifices;
(b) the membrane-type separation unit comprises a plurality of membrane modules and one or more control valves that control the fraction of membrane modules on-stream, the one or more control valves in signal communication with the controller; and
the controller is operable to control the flow rate of light noble gas from the source of the second gas to the second inlet of the gas mixer by adjusting the fraction of membrane modules on-stream; or
(c) the apparatus comprises a heat exchanger operative to control a temperature in the purification unit, the heat exchanger in signal communication with the controller; and
the controller is operable to control the flow rate of light noble gas from the source of the second gas to the second inlet of the gas mixer by adjusting the heat duty of the heat exchanger.

9. The apparatus according to claim 2 wherein the purification unit is an adsorption-type separation unit,
wherein at least one of
(a) the source of the second gas comprises the first outlet of the purification unit;
the adsorption-type separation unit comprises a plurality of vessels each containing a bed of adsorbent, and one or more control valves that control the fraction of the plurality of vessels on-stream, the one or more control valves in signal communication with the controller; and

the controller is operable to control the flow rate of light noble gas from the source of the second gas to the second inlet of the gas mixer by adjusting the fraction of the plurality of vessels on-stream;
(b) the source of the second gas comprises the first outlet of the purification unit;
the purification unit comprises a feed gas header,

the purification unit comprises one or more adjustable orifices operative to control a pressure in the feed gas header of the purification unit; and
the controller is operable to control the flow rate of light noble gas from the source of the second gas to the second i

Assignees

• Air Prod & Chem

Inventors

• Sanderson Cory E
• Ploeger Jason Michael
• Cao Jin
• Whitley Roger Dean
• Bhadra Shubhra Jyoti

Classifications

• C01B2210/0046

  Nitrogen · CPC title

• B01D2259/4061

  using five beds · CPC title

• C01B2210/0031

  Helium · CPC title

• B01D53/229

  Integrated processes (Diffusion and at least one other process, e.g. adsorption, absorption) · CPC title

• B01D53/053 Primary

  with storage or buffer vessel · CPC title