Air pollution control system and air pollution control method

Patent metadata

Field	Value
Publication number	US-9568193-B2
Application number	US-201214432449-A
Country	US
Kind code	B2
Filing date	Oct 11, 2012
Priority date	Oct 11, 2012
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

An air pollution control system includes: a desulfurization device which removes sulfur oxides in a flue gas generated from a boiler; a cooler which is provided at the downstream side of the desulfurization device, decreases a flue gas temperature and enlarges a particle diameter of SO 3 mist contained in the flue gas through cooling or heating the flue gas by a temperature adjustment means for adjusting a gas dew point temperature of the flue gas; and a CO 2 recovery device which includes a CO 2 absorber bringing CO 2 in the flue gas into contact with the CO 2 absorbent so as to remove CO 2 therefrom and a regenerator recovering CO 2 by dissociating CO 2 from the CO 2 absorbent and regenerating the CO 2 absorbent, wherein the flue gas is cooled by a cooling unit so as to enlarge the SO 3 mist in the flue gas.

First claim

The invention claimed is:

1. An air pollution control system comprising:
a desulfurization device which removes sulfur oxides in a flue gas generated from a boiler;
a cooler which is provided at the downstream side of the desulfurization device and includes a temperature adjustment means to adjust a gas dew point temperature of the flue gas to enlarge a particle diameter of SO3 mist contained in the flue gas; and
a CO 2 recovery device which includes a CO 2 absorber bringing CO 2 in the flue gas into contact with a CO 2 absorbent so as to remove CO 2 therefrom and a regenerator recovering CO 2 by dissociating CO 2 from the CO 2 absorbent and regenerating the CO 2 absorbent,
wherein the temperature adjustment means includes a cooling unit including a heat exchanger to cool the cooled water circulating inside the cooler to be lower by 20° C. or more from a flue gas introduction temperature.

2. The air pollution control system according to claim 1 ,
wherein a mist trapping means for trapping enlarged mist is provided near the top of the cooler.

3. The air pollution control system according to claim 1 , further comprising:
a basic substance introduction means which is provided between the desulfurization device and the cooler so as to introduce a basic substance into the flue gas.

4. The air pollution control system according to claim 1 ,
wherein the circulation water of the cooler is a desulfurization absorbent.

5. An air pollution control system comprising:
a desulfurization device which removes sulfur oxides in a flue gas generated from a boiler;
a cooler which is provided at the downstream side of the desulfurization device so as to remove sulfur oxides remaining in the flue gas and to decrease a gas temperature; and
a CO 2 recovery device which includes a CO 2 absorber bringing CO 2 in the flue gas into contact with a CO 2 absorbent so as to remove CO 2 therefrom and a regenerator recovering CO 2 by dissociating CO 2 from the CO 2 absorbent and regenerating the CO 2 absorbent,
wherein the CO 2 absorber includes
a CO 2 absorption unit which absorbs CO 2 in the flue gas containing CO 2 by the CO 2 absorbent,
a primary water washing unit which is provided at the downstream side of the CO 2 absorption unit in the gas flow direction so as to cool the flue gas, from which CO 2 has been removed by washing water, and to recover the entrained CO 2 absorbent by the washing water,
a circulation line which supplies the washing water containing the CO 2 absorbent recovered in a liquid storage tank of the primary water washing unit from the top of the primary water washing unit so as to circulate the washing water,
a preliminary water washing unit which is provided between the CO 2 recovery unit and the primary water washing unit,
wherein a part of the washing water containing the CO 2 absorbent is extracted from the primary water washing unit and the extracted washing water is supplied to the preliminary water washing unit, and wherein the CO 2 absorbent which is entrained in the flue gas from which CO 2 has been absorbed in the CO 2 absorption unit is preliminarily washed by the extracted washing water and a particle diameter of SO 3 mist containing the CO 2 absorbent is enlarged, and
a heater which heats the extracted washing water, wherein the heated washing water is supplied to the preliminary water washing unit.

6. The air pollution control system according to claim 5 , further comprising:
a mist trapping means which is provided between the preliminary water washing unit and the primary water washing unit so as to trap mist.

7. An air pollution control system comprising:
a desulfurization device which removes sulfur oxides in a flue gas generated from a boiler;
a cooler which is provided at the downstream side of the desulfurization device, enlarges a particle diameter of SO 3 mist contained in the flue gas through a temperature adjustment means for adjusting a gas dew point temperature of the flue gas and decreases a flue gas temperature; and
a CO 2 recovery device which includes a CO 2 absorber bringing CO 2 in the flue gas into contact with a CO 2 absorbent so as to remove CO 2 therefrom and a regenerator recovering CO 2 by dissociating CO 2 from the CO 2 absorbent and regenerating the CO 2 absorbent,
wherein the CO 2 absorber includes
a CO 2 absorption unit which absorbs CO 2 in the flue gas containing CO 2 by the CO 2 absorbent,
a primary water washing unit which is provided at the downstream side of the CO 2 absorption unit in the gas flow direction so as to cool the flue gas, from which CO 2 has been removed by washing water, and to recover the entrained CO 2 absorbent by the washing water,
a circulation line which supplies the washing water containing the CO 2 absorbent recovered in a liquid storage tank of the primary water washing unit from the top of the primary water washing unit so as to circulate the washing water,
a preliminary water washing unit which is provided between the CO 2 absorption unit and the primary water washing unit,
wherein a part of the washing water containing the CO 2 absorbent is extracted from the primary water washing unit and the extracted washing water is supplied to the preliminary water washing unit, and wherein the CO 2 absorbent which is entrained in the flue gas from which CO 2 has been absorbed in the CO 2 absorption unit is preliminarily washed by the extracted washing water and a particle diameter of SO 3 mist containing the CO 2 absorbent is enlarged, and
a heater which heats the extracted washing water,
wherein the heated washing water is supplied to the preliminary water washing unit.

8. The air pollution control system according to claim 7 , further comprising:
a mist trapping means which is provided between the preliminary water washing unit and the primary water washing unit so as to trap mist.

9. The air pollution control system according to claim 7 , further comprising:
a mist trapping means which is provided near the top of the cooler so as to trap enlarged mist.

10. The air pollution control system according to claim 7 ,
wherein the temperature adjustment means is a cooling means which includes a heat exchanger cooling the cooled water circulating inside the cooler to be lower by 20° C. or more from a flue gas introduction temperature.

11. The air pollution control system according to claim 7 ,
wherein the temperature adjustment means includes
a heating unit which includes a heater heating the circulation water circulating inside the cooler to be higher by 10° C. or more from the flue gas introduction temperature, and
a cooling unit which is provided at the downstream side of the heating unit and cools the heated flue gas to a CO 2 absorber introduction temperature or less.

12. The air pollution control system according to claim 7 , further comprising:
a basic substance introduction means which is provided between the desulfurization device and the cooler so as to introduce a basic substance into the flue gas.

13. The air pollution control system according to claim 7 ,
wherein the circulation water of the cooler is a desulfurization absorbent.

14. An air pollution control method comprising:
desulfurizing sulfur oxides in a flue gas generated from a boiler by a desulfurization device;
adjusting a flue gas temperature and to enlarge a particle diameter of SO 3 mist contained in the flue gas through cooling the cooled water circulating inside the cooler via circulation through a heat exchanger to be lower by 20° C. or more from a flue gas introduction temperature, or heating

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Oishi Tsuyoshi
• Tanaka Hiroshi
• Nagayasu Hiromitsu
• Hirata Takuya
• Kajiya Yoshinori
• Noborisato Tomoki

Classifications

• B01D2251/606

  Carbonates · CPC title

• B01D2252/103

  Water · CPC title

• B01D2258/0283

  Flue gases · CPC title

• B01D2252/30

  Ionic liquids and zwitter-ions · CPC title

• F23J2215/20

  Sulfur; Compounds thereof · CPC title