US-12623177-B2 - Carbon dioxide removal apparatus, carbon dioxide desorption determination method, and carbon dioxide separation method

US12623177B2US 12623177 B2US12623177 B2US 12623177B2US-12623177-B2

Abstract

Provided is a carbon dioxide removal apparatus that enables determination of whether or not carbon dioxide has desorbed from an adsorbent without using a carbon dioxide sensor. A carbon dioxide removal apparatus includes a carbon dioxide adsorption module, a first valve provided in an intake part of the carbon dioxide adsorption module, a second valve provided in a discharge part of the carbon dioxide adsorption module, a third valve connected to the discharge part, a vacuum pump connected to the carbon dioxide adsorption module via the third valve, and a controller. The carbon dioxide adsorption module includes a pressure meter and an adsorbent, and the controller is configured to perform, based on a pressure measured by the pressure meter, at least one of determining whether carbon dioxide has desorbed from the adsorbent or detecting an abnormality.

Inventors

Toshiyuki Inaba
Shumon HOSHINO
Masanobu Takazawa

Assignees

HONDA MOTOR CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20230927
Priority Date: 20220928

Claims (3)

1 . A carbon dioxide removal apparatus comprising: a carbon dioxide adsorption module; a first valve provided in an intake part of the carbon dioxide adsorption module; a second valve provided in a discharge part of the carbon dioxide adsorption module; a third valve connected to the discharge part; a vacuum pump connected to the carbon dioxide adsorption module via the third valve; and a controller, the carbon dioxide adsorption module comprising a pressure meter and an adsorbent, the controller being configured to bring a pressure in the carbon dioxide adsorption module into a predetermined reduced pressure state by operating the vacuum pump in a state in which the first valve and the second valve are closed and the third valve is open, and thereafter, and perform determination and/or detection based on a degree of increase in the pressure in the carbon dioxide adsorption module measured by the pressure meter in a state where the first, second, and third valves are all closed, wherein the controller determines that carbon dioxide has desorbed from the adsorbent, in a case where the degree of increase in the pressure is greater than 0, the controller detects an abnormality indicating that the carbon dioxide adsorption module is experiencing pressure leakage, in a case where the degree of increase in the pressure is higher than a predetermined first value, and the controller detects an abnormality indicating that the adsorbent has deteriorated, in a case where the degree of increase in the pressure is lower than a predetermined second value, and the degree of increase in the pressure includes at least one of a pressure value at a point in time when a predetermined time has elapsed from a start of measurement of the pressure, or a rate of increase in the pressure within a predetermined period after the start of the measurement of the pressure.
2 . A carbon dioxide desorption determination method performable by a carbon dioxide removal apparatus including: a carbon dioxide adsorption module provided with a pressure meter and an adsorbent; a first valve provided in an intake part of the carbon dioxide adsorption module; a second valve provided in a discharge part of the carbon dioxide adsorption module; a third valve connected to the discharge part; and a vacuum pump connected to the carbon dioxide adsorption module via the third valve, the carbon dioxide desorption determination method comprising: bringing a pressure in the carbon dioxide adsorption module into a predetermined reduced pressure state by operating the vacuum pump in a state in which the first valve and the second valve are closed and the third valve is open, closing the first valve, the second valve, and the third valve; measuring a pressure in the carbon dioxide adsorption module by the pressure meter; and performing determination and/or detection based on a degree of increase in the pressure in the carbon dioxide adsorption module measured by the pressure meter, the performing determination and/or detection including: determining that carbon dioxide has desorbed from the adsorbent in the carbon dioxide adsorption module, in a case where the degree of increase in the pressure is greater than 0; detecting an abnormality indicating that the carbon dioxide adsorption module is experiencing pressure leakage, in a case where the degree of increase in the pressure is higher than a predetermined first value, and detecting an abnormality indicating that the adsorbent has deteriorated, in a case where the degree of increase in the pressure is lower than a predetermined second value, wherein in the detecting the abnormalities, the degree of increase in the pressure includes at least one of a pressure value at a point in time when a predetermined time has elapsed from a start of measurement of the pressure, or a rate of increase in the pressure within a predetermined period after the start of the measurement of the pressure.
3 . A carbon dioxide separation method for separating carbon dioxide from air by a carbon dioxide removal apparatus including: a carbon dioxide adsorption module provided with a pressure meter and an adsorbent, a first valve provided in an intake part of the carbon dioxide adsorption module; a second valve provided in a discharge part of the carbon dioxide adsorption module; a third valve connected to the discharge part; a vacuum pump connected to the carbon dioxide adsorption module via the third valve; and a heater, the carbon dioxide separation method comprising: allowing the adsorbent to adsorb carbon dioxide from air; reducing a pressure in the carbon dioxide adsorption module using the vacuum pump in a state in which the first and second valves are closed and the third valve is open; continuously measuring the pressure in the carbon dioxide adsorption module by the pressure meter in a state in which the first, second, and third valves are closed and the heater is increasing a temperature of the adsorbent; and opening the third valve after the pressure measured by the pressure meter has stopped increasing, and causing the vacuum pump to start reducing the pressure in the carbon dioxide adsorption module, thereby desorbing the carbon dioxide adsorbed on the adsorbent.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to Japanese Patent Application No. 2022-155119 filed on Sep. 28, 2022. The entire contents of this application are hereby incorporated herein by reference. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a carbon dioxide removal apparatus, a carbon dioxide desorption determination method, and a carbon dioxide separation method. Related Art Efforts to mitigate climate change and reduce the effects of climate change are ongoing, and research and development to reduce carbon dioxide emissions are underway to achieve this goal. Some techniques have been proposed as the approaches to attain the goal. For example, according one proposed technique, carbon dioxide in the atmosphere is captured to be stored in the form of gas or liquid in the ground or the like. According to another proposed technique, captured carbon dioxide is used as a carbon source, and carbon is converted into valuable substances such as fuels and chemical products. In particular, with respect to carbon dioxide capture by direct air capture (DAC), it has been proposed to capture carbon dioxide by adsorption. For example, U.S. patent Application, Publication No. 2019/0255480 discloses a technique in which an adsorbent for adsorbing carbon dioxide is disposed in a plurality of layers on an adsorbent holding member. Patent Document 1: U.S. Published Patent Application Publication, No. 2019/0255480 SUMMARY OF THE INVENTION Incidentally, it is not easy to measure a concentration of carbon dioxide in a process for reducing carbon dioxide emissions by DAC. In DAC, desorption of carbon dioxide from an adsorbent takes place in a vacuum. On the other hand, ordinary carbon dioxide sensors are designed to be used under atmospheric pressure. For this reason, it is difficult to measure the concentration of carbon dioxide during a process step of desorbing carbon dioxide from the adsorbent. This means that it is difficult to determine whether or not carbon dioxide has desorbed from the adsorbent. In view of the foregoing circumstances, it is an object of the present invention to provide a carbon dioxide removal apparatus and a carbon dioxide desorption determination method that enable determination of whether or not carbon dioxide has desorbed from an adsorbent without using a carbon dioxide sensor. Thus, the present invention contributes, by extension, to mitigating climate change and reducing the effects of climate change. A first aspect of the present invention is directed to a carbon dioxide removal apparatus including: a carbon dioxide adsorption module; a first valve provided in an intake part of the carbon dioxide adsorption module; a second valve provided in a discharge part of the carbon dioxide adsorption module; a third valve connected to the discharge part; a vacuum pump connected to the carbon dioxide adsorption module via the third valve; and a controller. The carbon dioxide adsorption module includes a pressure meter and an adsorbent, and the controller is configured to perform, based on a pressure measured by the pressure meter, at least one of determining whether carbon dioxide has desorbed from the adsorbent or detecting an abnormality. The carbon dioxide removal apparatus having the above-described configuration makes it possible to determine whether or not carbon dioxide has desorbed from the adsorbent without using a carbon dioxide sensor. The carbon dioxide removal apparatus can further detect an abnormality in the apparatus by the simple mechanism. In the carbon dioxide removal apparatus according to a second aspect of the present invention, it is preferable that the controller detects different types of abnormalities according to a degree of increase in the pressure measured by the pressure meter. The carbon dioxide removal apparatus according to the above aspect can detect a plurality of types of abnormalities by means of one meter. In the carbon dioxide removal apparatus according to a third aspect of the present invention, it is preferable that the degree of increase in the pressure includes at least one of a pressure value at a point in time when a predetermined time has elapsed from a start of measurement of the pressure, or a rate of increase in the pressure within a predetermined period after the start of the measurement of the pressure. The carbon dioxide removal apparatus can according to the above aspect can detect a plurality of types of abnormalities by way of simple evaluation of physical properties. In the carbon dioxide removal apparatus according to a fourth aspect of the present invention, it is preferable that the controller determines that the carbon dioxide adsorption module is experiencing pressure leakage in a case where the degree of increase in the pressure measured by the pressure meter is higher than a predetermined value, and the controller determines that the adsorbent has deteriorated