Electrolysis device and electrolysis method

Patent metadata

Field	Value
Publication number	US-2025297389-A1
Application number	US-202519050426-A
Country	US
Kind code	A1
Filing date	Feb 11, 2025
Priority date	Mar 21, 2024
Publication date	Sep 25, 2025
Grant date	—

Abstract

An electrolysis device includes: an electrolysis cell; a cathode supply flow path; an anode supply flow path; a cathode discharge flow path; an anode discharge flow path; a cathode flow rate regulator to adjust a flow rate A of a cathode supply fluid; an anode flow rate regulator to adjust a flow rate B of a anode supply fluid; a first flowmeter to measure a flow rate C of a cathode discharge fluid; a second flowmeter to measure a flow rate D of a anode discharge fluid; and a control device to estimate a Faraday efficiency according to a relational expression for approximating the Faraday efficiency to a function including the C and D, and control the cathode flow rate regulator according to the estimated Faraday efficiency to control the A.

First claim

What is claimed is:

1 . An electrolysis device comprising:
an electrolysis cell having a cathode configured to reduce carbon dioxide to produce a carbon compound, an anode configured to oxidize water to produce oxygen, a cathode flow path facing on the cathode, and an anode flow path facing on the anode; a cathode supply flow path which is connected to an inlet of the cathode flow path and through which a cathode supply fluid to be supplied to the cathode flow path flows, the cathode supply fluid containing gas of the carbon dioxide; an anode supply flow path which is connected to an inlet of the anode flow path and through which an anode supply fluid to be supplied to the anode flow path flows, the anode supply fluid containing the water; a cathode discharge flow path which is connected to an outlet of the cathode flow path and through which a cathode discharge fluid to be discharged from the cathode flow path flows, the cathode discharge fluid containing the carbon compound and the carbon dioxide; an anode discharge flow path which is connected to an outlet of the anode flow path and through which an anode discharge fluid to be discharged from the anode flow path flows, the anode discharge fluid containing the oxygen and the water; a cathode flow rate regulator configured to adjust a flow rate A of the cathode supply fluid to be supplied to the cathode flow path; an anode flow rate regulator configured to adjust a flow rate B of the anode supply fluid to be supplied to the anode flow path; a first flowmeter configured to measure a flow rate C of the cathode discharge fluid to be discharged from the cathode flow path; a second flowmeter configured to measure a flow rate D of the anode discharge fluid to be discharged from the anode flow path; and a control device configured to receive a measured data of the flow rate C from the first flowmeter and a measured data of the flow rate D from the second flowmeter, wherein the control device is configured to
use the measured data of the flow rate C and the measured data of the flow rate D and estimate a value of a Faraday efficiency of the carbon compound according to a relational expression for approximating the value of the Faraday efficiency to a function including the flow rate C and the flow rate D, and
control the cathode flow rate regulator according to the estimated value of the Faraday efficiency to control the flow rate A.

2 . The electrolysis device according to claim 1 , wherein
the control device is configured to control the cathode flow rate regulator according to the estimated value of the Faraday efficiency to control the flow rate A so as to satisfy

I
×
13.93

+

(

x
-
1.33

)

×
1

≤
A
≤

I
×
13.93

+

(

x
-
1.33

)

×
1
⁢
0

where I represents a total reaction current value in the electrolysis cell, x satisfies x=D/(C−a), and a represents a flow rate of a gas of the carbon dioxide in the cathode discharge fluid.

3 . The electrolysis device according to claim 1 , wherein:
the first flowmeter is a first thermal mass flow meter; the second flowmeter is a second thermal mass flow meter; and the control device is configured to control the cathode flow rate regulator according to the estimated value of the Faraday efficiency to control the flow rate A so as to satisfy

I
×
13.93

+

(

x
-
1.4

)

×
1

≤
A
≤

I
×
13.93

+

(

x
-
1.4

)

×
7

where I represents a total reaction current value, x satisfies x=D/(C−a), and a represents a flow rate of unreduced excessive carbon dioxide in the carbon dioxide in the cathode discharge fluid.

4 . The electrolysis device according to claim 1 , wherein
the control device is connected to at least one instrument selected from the group consisting of a power source configured to supply current or voltage between the anode and the cathode, a cathode pressure regulator configured to control a pressure of the cathode flow path, an anode pressure regulator configured to control a pressure of the anode flow path, and a temperature regulator configured to adjust a temperature of the electrolysis cell.

5 . The electrolysis device according to claim 1 , wherein
the control device is configured to stop operation of the electrolysis cell when a value calculated by
(Cathode flow rate increase+D)/total reaction current value in the electrolysis cell/60 (s)/96500 (c/mol)/2 (reaction electron number)×22400 (cc/mol)/1.5

is 0.8 or less.

6 . The electrolysis device according to claim 1 , wherein:
the first flowmeter is a first thermal mass flow meter; the second flowmeter is a second thermal mass flow meter; and the control device is configured to stop operation of the electrolysis cell when a total Faraday efficiency of a reduction product by the electrolysis cell is 0.8 or less.

7 . The electrolysis device according to claim 1 , wherein
the control device is connected to a hydrogen supply source configured to supply a fluid containing hydrogen to a chemical synthesis reaction device following to the electrolysis device and configured to produce a compound by a chemical reaction using the carbon compound and the hydrogen.

8 . The electrolysis device according to claim 7 , wherein:
the first flowmeter is a first thermal mass flow meter; the second flowmeter is a second thermal mass flow meter; and the control device is configured to
calculate a flow rate of hydrogen produced by the electrolysis device from a value calculated from
I×6.964×(100−14.778x 2 −99.006x+205.41), and control the hydrogen supply source to decrease a flow rate of a fluid containing the hydrogen to be supplied to the chemical synthesis reaction device according to the calculated flow rate of the hydrogen.

9 . The electrolysis device according to claim 1 , further comprising:
a

Assignees

• Toshiba Kk

Inventors

• Ono Akihiko
• Kudo Yuki
• Kiyota Yasuhiro
• Kofuji Yusuke
• Kitagawa Ryota

Classifications

• C25B3/26

  of carbon dioxide · CPC title

• C25B3/07 Primary

  Oxygen containing compounds · CPC title

• C25B3/03

  Acyclic or carbocyclic hydrocarbons · CPC title

• C25B1/04

  by electrolysis of water · CPC title

• C25B1/23

  Carbon monoxide or syngas · CPC title