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Acetylene removal from light hydrocarbon mixtures by metal-organic framework exhibiting dual size and chemical selectivities

Foreign code F180009593
File No. 5506
Posted date Nov 16, 2018
Country United States of America
Application number 201715829067
Gazette No. 20180155258
Date of filing Dec 1, 2017
Gazette Date Jun 7, 2018
Priority data
  • P2016-235111 (Dec 2, 2016) JP
Title Acetylene removal from light hydrocarbon mixtures by metal-organic framework exhibiting dual size and chemical selectivities
Abstract The present invention provides a gas separation system and a gas separation method capable of separating various types of hydrocarbon gas with high selectivity, and a gas separation system is for separating one type or more of hydrocarbon gases from mixed gas consisting of two types or more of hydrocarbon gases; having a porous metal-organic complex having pores determined by metal ion-containing planar ligands facing each other and pillar ligands coordinating between the planar ligands, and a controller for controlling at least a pressure of the mixed gas; and in which the pressure is controlled to control adsorption of the hydrocarbon gas to the porous metal-organic complex or desorption thereof from the porous metal-organic complex.
Outline of related art and contending technology BACKGROUND OF THE INVENTION
Field of the Invention
The present invention is related to a gas separation system and a gas separation method.
Description of the Related Art
Ethylene is industrially produced by steam cracking or pyrolysis, alongside with acetylene as a by-product at concentrations of about 1%.Ethylene is a major chemical for the production of polymers (Ziegler-Natta reaction types) and of other useful chemicals.Acetylene acts as a major catalyst poison for the Ziegler-Natta catalyst used for the polymerization of ethylene.In addition, the presence of acetylene increases safety issues, because of the formation of explosive metal-acetylides with the polymerization catalyst.Therefore, the production of high-grade ethylene is of high and significant interest for the chemical industries.It is usually admitted that in order to have no significant influence of the acetylene over the polymerization process, acetylene concentration should be of less than few parts per million.
For ethylene purification from acetylene impurities, the use of metal-organic frameworks has been proposed in which copper (II) 4,4′-bipyrridine square grids are connected by inorganic ions ([SiF6]2-) between the grids (Non-Patent Document 1).
Scope of claims [claim1]
1. A gas separation system for separating one type or more of hydrocarbon gases from a mixed gas consisting of two or more types of hydrocarbon gases, the gas separation system comprising
a porous metal-organic complex having pores determined by metal ion-containing planar ligands facing each other and pillar ligands coordinating between the planar ligands, and
a controller adapted for controlling at least a pressure of the mixed gas; wherein the controller is further adapted to control the pressure of the mixed gas to control an adsorption of the hydrocarbon gas to the porous metal-organic complex or a desorption thereof from the porous metal-organic complex.
[claim2]
2. The gas separation system according to claim 1, wherein the planar ligand contains a polar structure having an unshared electron pair.
[claim3]
3. The gas separation system according to claim 2, wherein the polar structure is at least one selected from ―CO―, ―NH―, ―N═, ―O―, and ―CN.
[claim4]
4. The gas separation system according to claim 2, wherein a distance between the polar structures facing each other is 6 Å to 15 Å.
[claim5]
5. The gas separation system according to claim 1, wherein the pillar ligands are represented by any one of the following formulas (1) to (4):
wherein
a) in the formulas, R1, R2, R4, and R6 are each independently a hydrogen atom, an alkyl group, an alkoxy group, a hydroxy group, a halogen atom, an alkanoyl group, a hydroxyalkyl group, a phenyl group, a phenoxy group, a benzyl group, a phenethyl group, a carboxyl group, a cyano group, or a nitro group and further,
b) if there are a plurality of R1, R2, R4, and R6 respectively, those may be the same or different,
c) R3, R5, and R7 are independently a single bond or they represent divalent linking groups containing an unsaturated bond,
d) P is an integer of 1 to 4, q is an integer of 1 to 4, r is an integer of 1 to 4, and s is an integer of 1 to 3, and
e) X represents N, P, N→O, or P→O.
[claim6]
6. The gas separation system according to claim 1, wherein the mixed gas contains hydrocarbon gases of which pKa values are different by 10 or more to each other.
[claim7]
7. The gas separation system according to claim 1, wherein the hydrocarbon gases are at least two types of gas selected from methane, ethane, ethylene, and acetylene.
[claim8]
8. The gas separation system according to claim 1, wherein the controller is adapted to perform the following processes:
an adsorption process in which the pressure is applied so that the hydrocarbon gases other than the hydrocarbon gases that are the targets of separation are adsorbed by the porous metal-organic complex, and
a desorption process in which the pressure is reduced so that the adsorbed hydrocarbon gases are desorbed from the porous metal-organic complex.
[claim9]
9. A gas separation method for separating one or more types of hydrocarbon gases from mixed gas consisting of two or more types of hydrocarbon gases, comprising
a step of preparing a porous metal-organic complex having pores determined by metal ion-containing planar ligands facing each other and pillar ligands coordinating between the planar ligands and
an adsorption step of applying a pressure to the mixed gas so that the hydrocarbon gases other than the hydrocarbon gases that are the targets of separation are adsorbed by the porous metal-organic complex.
[claim10]
10. The gas separation method according to claim 9, further comprising a desorption step of reducing the pressure of the mixed gas so that the adsorbed hydrocarbon gases are desorbed gradually from the porous metal-organic complex after the adsorption step.
  • Inventor, and Inventor/Applicant
  • LAVENN Christophe
  • GINET Patrick
  • KITAGAWA Susumu
  • MATSUDA Ryotaro
  • L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
  • KYOTO UNIVERSITY
IPC(International Patent Classification)
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