CO2 recovery unit and CO2 recovery method

Patent metadata

Field	Value
Publication number	US-9987586-B2
Application number	US-201715397373-A
Country	US
Kind code	B2
Filing date	Jan 3, 2017
Priority date	Jul 10, 2014
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A CO 2 recovery unit includes a CO 2 -absorber that causes a gas containing CO 2 to contact a CO 2 -absorbing solution and that causes the CO 2 in the gas to be absorbed into the CO 2 -absorbing solution; a CO 2 -regenerator that heats the CO 2 -absorbing solution, releases the CO 2 from the CO 2 -absorbing solution, and regenerates the CO 2 -absorbing solution; and a CO 2 recovery amount controller that: calculates a computed target value of a CO 2 recovery amount and a computed target value of a CO 2 recovery rate based on a set value of the CO 2 recovery rate, actual measured values of CO 2 concentration, gas flow rate, and temperature of the gas, and calculates a maximum value of the CO 2 recovery amount in the CO 2 -absorber and a maximum value of the CO 2 recovery amount in the CO 2 -regenerator.

First claim

What is claimed:

1. A CO 2 recovery unit comprising:
a CO 2 -absorber in which a gas containing CO 2 contacts a CO 2 -absorbing solution that absorbs the CO 2 in the gas;
a CO 2 -regenerator that heats the CO 2 -absorbing solution that has absorbed the CO 2 from the gas, releases the CO 2 from the CO 2 -absorbing solution, and regenerates the CO 2 -absorbing solution; and
a CO 2 recovery amount controller that:
calculates a computed target value of a CO 2 recovery amount and a computed target value of a CO 2 recovery rate based on a set value of the CO 2 recovery rate, actual measured values of CO 2 concentration, gas flow rate, and temperature of the gas,
calculates a maximum value of the CO 2 recovery amount in the CO 2 -absorber and a maximum value of the CO 2 recovery amount in the CO 2 -regenerator, and
controls an amount of the CO 2 -absorbing solution supplied to the CO 2 -absorber, an amount of the CO 2 -absorbing solution supplied to the CO 2 -regenerator, and an amount of saturated steam supplied to a regeneration heater of the CO 2 -regenerator based on the set value of the CO 2 recovery rate or the computed target value of the CO 2 recovery rate,

wherein the CO 2 recovery amount controller controls the CO 2 recovery amount to a value less than or equal to the computed target value of the CO 2 recovery amount when any one of the actual measured values of the CO 2 concentration, gas flow rate, and temperature of the gas exceeds a predetermined threshold value.

2. The CO 2 recovery unit according to claim 1 ,
wherein the CO 2 recovery amount controller calculates the computed target value of the CO 2 recovery rate based on the following formulas (1) to (3):
Y 1= X 1× X 2× X 3×α  Formula (1)

Y 2=min( X 4, Y 1)  Formula (2)

Y 3= Y 2/( X 2× X 3×α)  Formula (3)

wherein, X1 represents the set value of the CO 2 recovery rate, X2 represents an actual measured value of the CO 2 concentration of the gas, X3 represents an actual measured value of the gas flow rate of the gas, X4 represents a maximum value of the CO 2 recovery amount, Y1 represents a target value of the CO 2 recovery amount, Y2 represents a computed target value of the CO 2 recovery amount, Y3 represents a computed target value of the CO 2 recovery rate, and a represents a conversion factor.

3. The CO 2 recovery unit according to claim 1 ,
wherein the CO 2 recovery amount controller:
calculates the computed target value of the CO 2 recovery rate based on the maximum value of the CO 2 recovery amount when a target value of the CO 2 recovery amount exceeds a maximum value of the CO 2 recovery amount, and
calculates the computed target value of the CO 2 recovery rate based on the calculated target value of the CO 2 recovery amount when the target value of the CO 2 recovery amount is less than or equal to the maximum value of the CO 2 recovery amount.

4. The CO 2 recovery unit according to claim 1 ,
wherein the CO 2 recovery amount controller feedback-controls an operation of the CO 2 recovery unit using the computed target value of the CO 2 recovery amount.

5. A CO 2 recovery method comprising: causing a gas containing CO 2 to contact a CO 2 -absorbing solution that absorbs the CO 2 in the gas in a CO 2 -absorber; heating the CO 2 -absorbing solution that has absorbed CO 2 from the gas, releasing the CO 2 from the CO 2 -absorbing solution, and regenerating the CO 2 -absorbing solution in a CO 2 -regenerator; calculating a computed target value of a CO 2 recovery amount and a computed target value of a CO 2 recovery rate based on a set value of the CO 2 recovery rate, actual measured values of CO 2 concentration, gas flow rate, and temperature of the gas with a CO 2 recovery amount controller; calculating a maximum value of the CO 2 recovery amount in the CO 2 -absorber and a maximum value of the CO 2 recovery amount in the CO 2 -regenerator with the CO 2 recovery amount controller; and controlling an amount of the CO 2 -absorbing solution supplied to the CO 2 -absorber, an amount of the CO 2 -absorbing solution supplied to the CO 2 regenerator, and an amount of saturated steam supplied to a regeneration heater of the CO 2 -regenerator based on the set value of the CO 2 recovery rate or the computed target value of the CO 2 recovery rate with the CO 2 recovery amount controller; and wherein the CO 2 recovery amount is controlled to a value less than or equal to the computed target value of the CO 2 recovery amount when any one of the actual measured values of the CO 2 concentration, gas flow rate, and temperature of the gas exceeds a predetermined threshold value.

6. The CO 2 recovery method according to claim 5 ,
wherein the computed target value of the CO 2 recovery rate is calculated based on the following formulas (1) to (3):
Y 1= X 1× X 2× X 3×α  Formula (1)

Y 2=min( X 4, Y 1)  Formula (2)

Y 3= Y 2/( X 2× X 3×α)  Formula (3)

wherein, X1 represents the set value of the CO 2 recovery rate, X2 represents an actual measured value of the CO 2 concentration of the gas, X3 represents an actual measured value of the gas flow rate of the gas to be treated, X4 represents a maximum value of the CO 2 recovery amount, Y1 represents a target value of the CO 2 recovery amount, Y2 represents a computed target value of the CO 2 recovery amount, Y3 represents a computed target value of the CO 2 recovery rate, and a represents a conversion factor.

7. The CO 2 recovery method according to claim 5 ,
wherein the computed target value of the CO 2 recovery rate is calculated based on a maximum value of the CO 2 recovery amount when a target value of the CO 2 recovery amount exceeds a maximum value of the CO 2 recovery amount; and
the computed target value of the CO 2 recovery rate is calculated based on the target value of the CO 2 recovery amount when the target value of the CO 2 recovery amount is less than or equal to the maximum value of the CO 2 recovery amount.

8. The CO 2 recovery method according to claim 5 , wherein the method is performed by a CO 2 recovery unit and the method further comprises feedback-controlling an operation of the CO 2 recovery unit using the computed target value of the CO 2 recovery amount.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Nakagawa Yosuke
• Shimada Daisuke
• Tsujiuchi Tatsuya

Classifications

• B01D2252/20478

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• B01D53/1425

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• B01D53/1475

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• B01D2258/0283

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• B01D53/62

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