Dehydration device, dehydration-compression system, CO2 recovery system, and dehydration device control method

Patent metadata

Field	Value
Publication number	US-11192061-B2
Application number	US-201916696107-A
Country	US
Kind code	B2
Filing date	Nov 26, 2019
Priority date	Nov 26, 2019
Publication date	Dec 7, 2021
Grant date	Dec 7, 2021

Abstract

A dehydration device removes moisture from a process gas compressed by a compressor, and includes a contactor that causes a dehydration solvent to absorb the moisture, a still column that separates the moisture from the dehydration solvent, a carrying line that carries the dehydration solvent from the contactor to the still column, a dehydration solvent conveying pump, a bypass line that couples the carrying lines upstream and downstream of the dehydration solvent conveying pump, a first on-off valve disposed in the bypass line, and a control device. In a case where the pressure detected by a pressure sensor is lower than a first predetermined pressure, the control device closes the first on-off valve and causes the conveying pump to operate, whereas in a case where the pressure detected by the pressure sensor is equal to or higher than the first predetermined pressure, the control device opens the first on-off valve and causes the conveying pump to stop.

First claim

The invention claimed is:

1. A dehydration device that removes moisture from a moisture-containing process gas compressed by a compressor, comprising:
an absorbing unit that causes the process gas to come into contact with a dehydration solvent, causing the dehydration solvent to absorb the moisture and remove the moisture from the process gas;
a first pressure detecting unit that detects an internal pressure of the absorbing unit;
a distilling unit that heats the dehydration solvent that has absorbed the moisture in the absorbing unit, and separates the moisture from the dehydration solvent;
a carrying line that carries the dehydration solvent from the absorbing unit to the distilling unit;
a conveying pump, disposed in the carrying line, that suctions the dehydration solvent carried from the absorbing unit and discharges the dehydration solvent toward the distilling unit;
a first bypass line that couples the carrying line upstream of the conveying pump and the carrying line downstream of the conveying pump;
a first on-off valve disposed in the first bypass line; and
a control unit that controls the conveying pump and the first on-off valve, wherein
the control unit is configured to close the first on-off valve and cause the conveying pump to operate in a case where the pressure detected by the first pressure detecting unit is lower than a first predetermined pressure, whereas the control unit is configured to open the first on-off valve and cause the conveying pump to stop in a case where the pressure detected by the first pressure detecting unit is equal to or higher than the first predetermined pressure.

2. The dehydration device according to claim 1 , wherein the first predetermined pressure is a pressure allowing the dehydration solvent to be conveyed from the absorbing unit to the distilling unit through the carrying line.

3. The dehydration device according to claim 1 , further comprising:
an evaporating unit, disposed in the carrying line, that reduces the pressure of the dehydration solvent and causes the process gas absorbed by the dehydration solvent to evaporate;
a second bypass line that couples the carrying line upstream of the evaporating unit and the carrying line downstream of the evaporating unit; and
a second on-off valve disposed in the second bypass line, wherein
the control unit is configured to open the second on-off valve in a case where the pressure detected by the first pressure detecting unit is lower than the first predetermined pressure, whereas the control unit closes the second on-off valve in a case where the pressure detected by the first pressure detecting unit is equal to or higher than the first predetermined pressure.

4. The dehydration device according to claim 3 , wherein the first predetermined pressure is a pressure allowing the dehydration solvent to be conveyed from the absorbing unit to the distilling unit through the carrying line.

5. A dehydration device that removes moisture from a moisture-containing process gas compressed by a compressor, comprising:
a absorbing unit that causes the process gas to come into contact with a dehydration solvent, causing the dehydration solvent to absorb the moisture and remove the moisture from the process gas;
a pressurizing unit that supplies a gas for pressurization to the absorbing unit;
a pressure detecting unit that detects an internal pressure of the absorbing unit;
a distilling unit that heats the dehydration solvent that has absorbed the moisture in the absorbing unit, and separates the moisture from the dehydration solvent;
a supply line that supplies the process gas compressed by the compressor to the absorbing unit;
a carrying line that carries the dehydration solvent from the absorbing unit to the distilling unit;
a discharge line that discharges the process gas with the moisture removed in the absorbing unit;
a coupling line that couples the supply line and the discharge line;
a supply valve disposed in the supply line farther downstream than a position of coupling with the coupling line;
a coupling valve disposed in the coupling line;
a discharge valve disposed in the discharge line; and
a control unit that controls the supply valve, the coupling valve, and the discharge valve, wherein
the control unit is configured to close the supply valve and the discharge valve and open the coupling valve in a case where the pressure detected by the pressure detecting unit is lower than a predetermined pressure, whereas the control unit is configured to open the supply valve and the discharge valve and close the coupling valve in a case where the pressure detected by the pressure detecting unit is equal to or higher than the predetermined pressure.

6. The dehydration device according to claim 5 , wherein the predetermined pressure is a pressure allowing the dehydration solvent to be conveyed from the absorbing unit to the distilling unit through the carrying line.

7. A dehydration-compression system comprising:
the dehydration device according to claim 1 ;
a first compressor that compresses the moisture-containing process gas; and
a second compressor that is supplied with the process gas with the moisture removed from the dehydration device and also compresses the process gas.

8. A CO 2 recovery system comprising:
a CO 2 absorbing tower that causes a CO 2 -containing exhaust gas to come into contact with a CO 2 absorbing liquid and remove the CO 2 in the exhaust gas;
an absorbing liquid regenerating tower that causes the CO 2 to be released from the CO 2 absorbing liquid that has absorbed the CO 2 in the CO 2 absorbing tower; and
the dehydration-compression system according to claim 7 that compresses the CO 2 released in the absorbing liquid regenerating tower and also removes moisture contained in the CO 2 .

9. A dehydration device control method that removes moisture from a moisture-containing process gas compressed by a compressor,
the dehydration device including:
a absorbing unit that causes the process gas to come into contact with a dehydration solvent, causing the dehydration solvent to absorb the moisture and remove the moisture from the process gas;
a distilling unit that heats the dehydration solvent that has absorbed the moisture in the absorbing unit, and separates the moisture from the dehydration solvent;
a carrying line that carries the dehydration solvent from the absorbing unit to the distilling unit;
a conveying pump, disposed in the carrying line, that suctions the dehydration solvent carried from the absorbing unit and discharges the dehydration solvent toward the distilling unit;
a first bypass line that couples the carrying line upstream of the conveying pump and the carrying line downstream of the conveying pump; and
a first on-off valve disposed in the first bypass line,

the method comprising:
a first pressure detecting step of detecting an internal pressure of the absorbing unit;
a first controlling step of closing the first on-off valve and causing the conveying pump to operate in a case where the pressure detected in the first pressure detecting step is lower than a first predetermined pressure; and
a second controlling step of opening the first on-off valve and stopping the conveying pump in a case where the pressure detected in the first pressure detecting step is equal to or higher than the first predetermined pressure.

10. A dehydration device control method that removes moisture from a moisture-containing process gas compressed by a compressor,
the dehydration device including:
a absorbing unit that causes the process gas to come into contact with a dehydration solvent, causing the dehydration solvent to absorb the moisture and

Assignees

• Mitsubishi Heavy Ind Eng Ltd

Inventors

• Miyamoto Osamu
• Inui Masayuki
• Yonekawa Takahito

Classifications

• B01D53/1425

  Regeneration of liquid absorbents · CPC title

• B01D3/02

  in boilers or stills · CPC title

• B01D3/143

  by two or more of a fractionation, separation or rectification step · CPC title

• B01D53/1412 Primary

  Controlling the absorption process · CPC title

• B01D53/1418

  Recovery of products · CPC title