Hydrocarbon Recovery with Pressure Swing Adsorption

Patent metadata

Field	Value
Publication number	US-2016144313-A1
Application number	US-201514957412-A
Country	US
Kind code	A1
Filing date	Dec 2, 2015
Priority date	Nov 21, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

A process for component separation in a polymer production system comprising: (a) separating a polymerization product into a gas stream and a polymer stream; (b) processing the gas stream in distillation columns to yield a light hydrocarbon stream (LHS) comprising ethylene and ethane; (c) contacting LHS with a purged hydrocarbon adsorber to yield a loaded hydrocarbon adsorber and a non-adsorbed gas stream, wherein ethane is adsorbed by the purged hydrocarbon adsorber at a first pressure to yield adsorbed ethane, and wherein the non-adsorbed gas stream comprises recovered ethylene; (d) contacting the loaded hydrocarbon adsorber with a sweeping gas stream at a second pressure to yield an unloaded hydrocarbon adsorber and a recovered adsorbed gas stream comprising the sweeping gas stream and desorbed ethane; and (e) contacting the unloaded hydrocarbon adsorber with the sweeping gas stream at the first pressure to yield the purged hydrocarbon adsorber and a spent sweeping gas.

First claim

We claim:

1 . A pressure swing adsorption system comprising:
at least two pressure swing adsorption units operated in parallel; a hydrocarbon feed stream to each pressure swing absorption unit, wherein the hydrocarbon feed stream comprises a first hydrocarbon and a second hydrocarbon; a hydrocarbon adsorber bed disposed in each pressure swing absorption unit, wherein the hydrocarbon adsorber bed comprises a hydrocarbon adsorber and wherein the hydrocarbon adsorber has an adsorption selectivity of the first hydrocarbon versus the second hydrocarbon as determined by volumetric adsorption at 298 K and at a first pressure of equal to or greater than about 2; and a sweeping gas stream to each pressure swing absorption unit; wherein upon contact of the hydrocarbon feed with the hydrocarbon adsorber at the first pressure the hydrocarbon adsorber adsorbs the first hydrocarbon to yield a loaded hydrocarbon adsorber comprising adsorbed first hydrocarbon and a non-adsorbed gas stream comprising the second hydrocarbon; wherein the hydrocarbon adsorber regenerates at a second pressure to yield an unloaded hydrocarbon adsorber and a desorbed first hydrocarbon and wherein the first pressure is greater than the second pressure by equal to or greater than about 400 kPa; and wherein the unloaded hydrocarbon adsorber is contacted with the sweeping gas stream to yield a purged hydrocarbon adsorber.

2 . The pressure swing adsorption system of claim 1 , wherein the hydrocarbon adsorber bed has a bed thickness of from about 0.1 ft to about 20 ft.

3 . The pressure swing adsorption system of claim 1 , wherein the pressure swing adsorption unit has a cylindrical geometry.

4 . The pressure swing adsorption system of claim 1 , wherein open flow channels are provided through the hydrocarbon adsorber bed.

5 . The pressure swing adsorption system of claim 4 , wherein the open flow channels comprise structurally added elements to the pressure swing adsorption unit, perforated tubes that enable gas flow, spacers, spaces between hydrocarbon adsorber particles, hydrocarbon adsorber pores, support pores, or combinations thereof.

6 . The pressure swing adsorption system of claim 5 , wherein the spacers comprise dimples or corrugations within a support, wherein the dimples or corrugations have a predetermined size to provide a desired flow channel volume of the open flow channels; particles; glass microspheres; wires of suitable size; or combinations thereof.

7 . The pressure swing adsorption system of claim 1 , wherein the hydrocarbon adsorber comprises a zeolitic imidazolate framework (ZIF).

8 . The pressure swing adsorption system of claim 7 , wherein the zeolitic imidazolate framework is characterized by a pore window size of from about 0.2 nm to about 0.5 nm.

9 . The pressure swing adsorption system of claim 7 , wherein the zeolitic imidazolate framework comprises ZIF-7, ZIF-8, ZIF-65, ZIF-67, or combinations thereof.

10 . The pressure swing adsorption system of claim 1 , wherein the hydrocarbon adsorber further comprises a support, wherein the zeolitic imidazolate framework contacts at least a portion of the support, is distributed throughout the support, or combinations thereof.

11 . The pressure swing adsorption system of claim 10 , wherein the support has a porosity of from about 0 vol. % to about 99 vol. % based on the total volume of the support.

12 . The pressure swing adsorption system of claim 10 , wherein the support comprises a support outer surface, wherein at least a portion of the support outer surface is in contact with the zeolitic imidazolate framework.

13 . The pressure swing adsorption system of claim 1 , wherein the first pressure is from about 600 kPa to about 3,000 kPa.

14 . The pressure swing adsorption system of claim 1 , wherein the first hydrocarbon is a saturated hydrocarbon, and wherein the second hydrocarbon is an olefin.

15 . The pressure swing adsorption system of claim 1 , wherein the pressure swing adsorption unit is characterized by a cycle time of from about 10 seconds to about 1 hour.

16 . The pressure swing adsorption system of claim 1 , wherein from about 2 to about 8 pressure swing adsorption units are operated in parallel.

17 . A pressure swing adsorption system comprising:
a first pressure swing adsorption unit and a second pressure swing adsorption unit operated in parallel; a hydrocarbon feed stream to each pressure swing absorption unit, wherein the hydrocarbon feed stream comprises a saturated hydrocarbon and an olefin; a hydrocarbon adsorber bed disposed in each pressure swing absorption unit, wherein the hydrocarbon adsorber bed comprises a hydrocarbon adsorber and wherein the hydrocarbon adsorber has an adsorption selectivity of the saturated hydrocarbon versus the olefin as determined by volumetric adsorption at 298 K and at a first pressure of equal to or greater than about 2; and a sweeping gas stream to each pressure swing absorption unit; wherein each of the first pressure swing adsorption unit and the second pressure swing adsorption unit independently and successively cycles through each of an adsorption step, a desorption step, and a purging step; wherein the hydrocarbon adsorber of each of the first pressure swing adsorption unit and the second pressure swing adsorption unit is independently contacted with the sweeping gas stream during the purging step to yield a purged hydrocarbon adsorber; wherein each of the first pressure swing adsorption unit and the second pressure swing adsorption unit independently adsorbs at the first pressure during the adsorption step, wherein the purged hydrocarbon adsorber adsorbs the saturated hydrocarbon to yield a loaded hydrocarbon adsorber comprising an adsorbed saturated hydrocarbon and a non-adsorbed gas stream comprising the olefin; wherein each of the first pressure swing adsorption unit and the second pressure swing adsorption unit independently regenerates at a second pressure during the desorption step, wherein the loaded hydrocarbon adsorber is regenerated to yield an unloaded hydrocarbon adsorber and a desorbed saturated hydrocarbon; wherein the first pressure is greater than the second pressure by equal to or greater than about 400 kPa; and wherein the first pressure swing adsorption unit and the second pressure swing adsorption unit are offset operationally such that at any given time one of the units is ready to or undergoing the adsorption step, thereby providing for a continuous process.

18 . The pressure swing adsorption system of claim 17 , wherein while the first pressure swing adsorption unit undergoes the adsorption step, the second pressure swing adsorption unit undergoes successively both the desorption step and the purging step.

19 . The pressure swing adsorption system of claim 18 , wherein the hydrocarbon adsorber bed has a bed thickness of from about 0.1 ft to about 20 ft; wherein open flow channels are provided through the hydrocarbon adsorber bed; wherein the hydrocarbon adsorber comprises a zeolitic imidazolate framework (ZIF) characterized by a pore window size of from about 0.2 nm to about 0.5 nm; and wherein the zeolitic imidazolate framework comprises ZIF-7, ZIF-8, ZIF-65, ZIF-67, or combinations thereof.

20 . A pressure swing adsorption system comprising:
a first pressure swing adsorption unit, a second pressure swing adsorption unit, and a third pressure swing adsorption unit operated in parallel; a hydrocarbon feed stream to each pressure swing absorption unit, wherein the h

Assignees

• Chevron Phillips Chemical Co

Inventors

• Ji Lei
• Chang Ai-Fu

Classifications

• C07C7/005 Primary

  Processes comprising at least two steps in series · CPC title

• B01D2259/402

  using two beds · CPC title

• B01D2253/108

  Zeolites · CPC title

• C07C7/12

  by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers · CPC title

• C07C7/13

  by molecular-sieve technique · CPC title