AMOUNT OF SEAWATER CONTROL DEVICE FOR SCRUBBER, AMOUNT OF SEAWATER CONTROL METHOD FOR SCRUBBER, AND AMOUNT OF ALKALI CONTROL DEVICE AND AMOUNT OF ALKALI CONTROL METHOD

• US 20150209720A1
• Filed: 04/06/2015
• Published: 07/30/2015
• Est. Priority Date: 01/29/2013
• Status: Active Grant

• Current Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Inventors: KOMATSU, Tadashi, TAKAHASHI, Kuniyuki
• Granted Patent: US 10,150,078 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01D 2251/304 of sodium
• CPC Class Codes: B01D 2252/1035 Sea water
• CPC Class Codes: B01D 2258/0283 Flue gases
• CPC Class Codes: B01D 53/1412 Controlling the absorption process
• CPC Class Codes: B01D 53/185 Liquid distributors
• CPC Class Codes: B01D 53/501 by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
• CPC Class Codes: B01D 53/507 by treating the gases with other liquids
• CPC Class Codes: G05D 7/0682 using a plurality of flow sources
• CPC Class Codes: G05D 9/12 characterised by the use of electric means
• CPC Class Codes: Y10T 137/0324 With control of flow by a condition or characteristic of a fluid
• CPC Class Codes: Y10T 137/86027 Electric

Abstract

An amount of seawater control device controls an amount of seawater supplied to a scrubber that purifies sulfur oxide contained in exhaust gas by bringing the sulfur oxide into contact with seawater. The control device includes a minimum amount of seawater converter which calculates a minimum amount of seawater necessary for an absorption reaction of the sulfur oxide by the seawater, an amount of seawater correction converter which calculates a corrected amount of seawater which is an amount of seawater at which the sulfur oxide contained in the exhaust gas discharged into atmosphere from the scrubber is equal to or less than a set variable, a summing element which calculates a set amount of seawater by summing the minimum amount of seawater and the corrected amount of seawater, and a pump control device which implements control such that seawater corresponding to the set amount is supplied to the scrubber.

Claims

1. An amount of seawater control device for a scrubber, which controls an amount of seawater supplied to a scrubber that purifies sulfur oxide contained in exhaust gas by bringing the sulfur oxide into contact with seawater, comprising:

a minimum amount of seawater converter which calculates a minimum amount of seawater which is a minimum amount of seawater necessary for an absorption reaction of the sulfur oxide by the seawater, from an engine output and a sulfur content of fuel oil;

an amount of seawater correction converter which calculates a corrected amount of seawater which is an amount of seawater at which the sulfur oxide contained in the exhaust gas discharged into atmosphere from the scrubber is equal to or less than a set variable;

a summing element which calculates a set amount of seawater by summing the minimum amount of seawater and the corrected amount of seawater; and

a pump control device which implements control such that seawater corresponding to the set amount of seawater is supplied to the scrubber.

2. The amount of seawater control device for a scrubber according to claim 1, further comprising a converter which calculates the set variable from a concentration of sulfur oxide contained in the exhaust gas discharged into the atmosphere from the scrubber, and an emission ratio of the sulfur oxide in waters being travelled.

3. The amount of seawater control device for a scrubber according to claim 1, further comprising a PID (proportional, integral and derivative) controller which calculates by PID a deviation between the set variable and the concentration of the sulfur oxide contained in the exhaust gas discharged into the atmosphere from the scrubber, and which supplies a manipulative variable to the amount of seawater correction converter.

4. The amount of seawater control device for a scrubber according to claim 1, wherein the pump control device has a plurality of inverters, and a pump flow rate setting device which starts and stops operation of a pump by the plurality of inverters, and changes a flow rate of the pump, in accordance with the set amount of seawater.

12. The amount of seawater control device for a scrubber according to claim 2, further comprising a PID (proportional, integral and derivative) controller which calculates by PID a deviation between the set variable and the concentration of the sulfur oxide contained in the exhaust gas discharged into the atmosphere from the scrubber, and which supplies a manipulative variable to the amount of seawater correction converter.

13. The amount of seawater control device for a scrubber according to claim 2, wherein the pump control device has a plurality of inverters, and a pump flow rate setting device which starts and stops operation of a pump by the plurality of inverters, and changes a flow rate of the pump, in accordance with the set amount of seawater.

5. An amount of seawater control method for a scrubber, which controls an amount of seawater supplied to a scrubber that purifies sulfur oxide contained in exhaust gas by bringing the sulfur oxide into contact with seawater, comprising the steps of:

calculating a minimum amount of seawater which is a minimum amount of seawater necessary for an absorption reaction of the sulfur oxide by the seawater, from an engine output and a sulfur content of fuel oil;

calculating a corrected amount of seawater which is an amount of seawater at which the sulfur oxide contained in the exhaust gas discharged into atmosphere from the scrubber is equal to or less than a set variable;

calculating a set amount of seawater by summing the minimum amount of seawater and the corrected amount of seawater; and

implementing control such that seawater corresponding to the set amount of seawater is supplied to the scrubber.

6. An amount of alkali control device, which controls an amount of alkali injected into seawater supplied to a scrubber that purifies sulfur oxide contained in exhaust gas by bringing the sulfur oxide into contact with seawater, comprising:

a minimum amount of seawater converter which calculates a minimum amount of seawater which is a minimum amount of seawater necessary for an absorption reaction of the sulfur oxide by the seawater, from an engine output and a sulfur content of fuel oil;

an amount of seawater correction converter which calculates a corrected amount of seawater which is an amount of seawater at which the sulfur oxide contained in the exhaust gas discharged into atmosphere from the scrubber is equal to or less than a set variable;

a summing element which calculates a set amount of seawater by summing the minimum amount of seawater and the corrected amount of seawater;

a pump control device which implements control such that seawater corresponding to the set amount of seawater is supplied to the scrubber;

an amount of alkali calculator which calculates an alkali injection amount from an amount of an alkali component which is contained in seawater corresponding to the set amount of seawater; and

an alkali pump control device which implements control in such a manner that an alkali agent corresponding to the alkali injection amount is injected into the seawater which is supplied to the scrubber.

7. The amount of alkali control device according to claim 6,

wherein the scrubber is configured so as to be able to supply recycled seawater obtained by recycling seawater which has been used for purification, and fresh seawater which has not been used for purification,

the amount of alkali control device further comprises a summing and subtracting element which calculates an amount of seawater corresponding to a difference obtained by subtracting an amount of fresh seawater from the set amount of seawater, and the amount of alkali calculator calculates an alkali injection amount from an amount of an alkali component which is contained in seawater of the amount corresponding to the difference.

8. The amount of alkali control device according to claim 6, further comprising an upper and lower limiter which restricts the amount of seawater supplied to the scrubber to within a range between upper and lower limit values.

9. The amount of alkali control device according to claim 6, further comprising a converter which calculates the set variable from a concentration of sulfur oxide contained in the exhaust gas discharged into the atmosphere from the scrubber, and an emission ratio of the sulfur oxide in waters being travelled.

10. The amount of alkali control device according to claim 6, wherein the pump control device has a plurality of inverters, and a pump flow rate setting device which starts and stops operation of a pump by the plurality of inverters, and changes a flow rate of the pump, in accordance with the set amount of seawater.

14. The amount of alkali control device according to claim 7, further comprising an upper and lower limiter which restricts the amount of seawater supplied to the scrubber to within a range between upper and lower limit values.

15. The amount of alkali control device according to claim 7, further comprising a converter which calculates the set variable from a concentration of sulfur oxide contained in the exhaust gas discharged into the atmosphere from the scrubber, and an emission ratio of the sulfur oxide in waters being travelled.

16. The amount of alkali control device according to claim 7, wherein the pump control device has a plurality of inverters, and a pump flow rate setting device which starts and stops operation of a pump by the plurality of inverters, and changes a flow rate of the pump, in accordance with the set amount of seawater.

11. An amount of alkali control method, which controls an amount of alkali injected into seawater supplied to a scrubber that purifies sulfur oxide contained in exhaust gas by bringing the sulfur oxide into contact with seawater, comprising the steps of:

calculating a minimum amount of seawater which is a minimum amount of seawater necessary for an absorption reaction of the sulfur oxide by the seawater, from an engine output and a sulfur content of fuel oil;

calculating a corrected amount of seawater which is an amount of seawater at which the sulfur oxide contained in the exhaust gas discharged into atmosphere from the scrubber is equal to or less than a set variable;

calculating a set amount of seawater by summing the minimum amount of seawater and the corrected amount of seawater;

calculating an alkali injection amount from an amount of an alkali component which is contained in seawater corresponding to the set amount of seawater; and

implementing control in such a manner that an alkali agent corresponding to the alkali injection amount is injected into recycled seawater which is supplied to the scrubber.

17. A method, comprising:

calculating a first amount of seawater for obtaining an absorption reaction with a first amount of sulfur oxide in an exhaust gas;

calculating a second amount of seawater based on processing variables including a second amount of sulfur oxide in scrubbed exhaust gas that is discharged by a scrubber for scrubbing the exhaust gas;

calculating a third amount of seawater based on the first amount of seawater and the second amount of seawater; and

supplying the third amount of seawater to the scrubber.

18. The method of claim 17, wherein the calculating the first amount of seawater comprises processing variables including an engine output value and a sulfur content of fuel oil.

19. The method of claim 18, wherein the calculating the second amount of seawater comprises processing variables including a CO₂ concentration in the scrubbed exhaust gas and a designated emission ratio.

20. The method of claim 19, wherein the calculating the second amount of seawater further comprises performing PID (proportional, integral and derivative)control based on:

a set variable corresponding to an amount of sulfur oxide to be purified based at least partly on the designated emission ratio and the CO₂ concentration; and

the second amount of sulfur oxide in the scrubbed exhaust gas.