CO 2 recovery system and waste-product removing method

• US 8,137,441 B2
• Filed: 10/31/2007
• Issued: 03/20/2012
• Est. Priority Date: 03/14/2007
• Status: Active Grant

• Current Assignee: Kansai Electric Power Company Incorporated, Mitsubishi Heavy Industries Engineering, Ltd. (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Kansai Electric Power Company Incorporated, Mitsubishi Heavy Industries, Ltd.
• Inventors: Iijima, Masaki, Mimura, Tomio, Yagi, Yasuyuki
• Primary Examiner(s): Smith, Duane
• Assistant Examiner(s): MCKENZIE, THOMAS B
• Application Number:
  US11/932,073
• Publication Number:
  US 20080223215A1
• Time in Patent Office: 1,602 Days
• Field of Search: 95149-250, 962/42, 96243-371, 423210-248
• US Class Current: 95/183
• CPC Class Codes: B01D 53/1425 Regeneration of liquid absorbents
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: C01B 32/50 Carbon dioxide
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 20/151 Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

A CO₂ recovery system includes an absorption tower and a regeneration tower. CO₂ rich solution is produced in the absorption tower by absorbing CO₂ from CO₂-containing gas. The CO₂ rich solution is conveyed to the regeneration tower where lean solution is produced from the rich solution by removing CO₂. A reclaimer heats the lean solution that is produced in the regeneration tower to produce a condensed waste-product from the lean solution by condensing a depleted material contained in the lean solution, and removes the condensed waste-product. A cooler cools the condensed waste-product.

Claims

1. A CO₂ recovery system comprising:

an absorption tower suitable for receiving a CO₂-containing gas and a CO₂-absorbing solution, and the absorption tower suitable for causing the CO₂-containing gas to come in contact with the CO₂-absorbing solution to produce a CO₂ rich solution, and

a regeneration tower suitable for receiving the CO₂ rich solution and suitable for producing a lean solution from the CO₂ rich solution by removing CO₂ from the CO₂ rich solution,

a reclaimer suitable for receiving a part of lean solution, produced in the regeneration tower and removed via an extracting line when a first valve is open, wherein the reclaimer further comprises an external water source suitable for supplying water to the reclaimer when a second valve is open, a heating means suitable for heating the part of lean solution to obtain a heated condensed waste-product from the part of lean solution and to obtain a vaporized CO₂ absorbing solution, a means for feeding the vaporized CO₂ absorbing solution via a vaporized CO₂-absorbing solution supply line to a lower portion of the regeneration tower when a third valve is open, and a means for conveying a part of heated condensed waste-product from the whole heated condensed waste-product when the third valve is closed but a fourth valve is open, and wherein the first valve is arranged on the extracting line and below the reclaimer, the second valve is arranged on the water supply line and below the reclaimer, the third valve is arranged on the vaporized CO₂-absorbing solution supply line and above the reclaimer, and the fourth valve is arranged below the reclaimer;

a cooling unit suitable for receiving the part of heated condensed waste-product from the reclaimer to be cooled to the specified temperature every time, the cooling unit suitable for cooling the part of heated condensed waste-product by coolant water that is poured into the cooling unit via a coolant water supply line when the fourth valve and a fifth valve are closed, wherein the cooling unit further comprises a means for conveying a part of cooled condensed waste-product when the fourth valve is closed but the fifth valve is open, and wherein the fifth valve is arranged below the cooling unit; and

a receiving tank suitable for receiving the part of condensed waste-product cooled by the cooling unit.

2. The CO₂ recovery system according to claim 1, in which the coolant temperature of the condensed waste-product in the cooling unit is equal to or below 50°

C.

3. A method of removing waste-product in a CO₂ recovery system comprising:

an absorption tower suitable for receiving a CO₂-containing gas and a CO₂-absorbing solution, and the absorption tower suitable for causing the CO₂-containing gas to come in contact with the CO₂-absorbing solution to produce a CO₂ rich solution, and

a regeneration tower suitable for receiving the CO₂ rich solution and suitable for producing a lean solution from the CO₂ rich solution by removing CO₂ from the CO₂ rich solution,

taking out a part of lean solution produced in the regeneration tower and heating the part of lean solution in a reclaimer to obtain a heated condensed waste-product from the part of lean solution, wherein the reclaimer is arranged below the regeneration tower;

taking out a part of heated condensed waste-product obtained from the reclaimer from the whole condensed waste-product, and cooling the part of heated condensed waste-product in a cooling unit every time to a specified temperature to produce a cooled condensed waste-product and removing the part of cooled condensed waste product, and feeding the CO₂ absorbing solution vaporized in the reclaimer to the regeneration tower, wherein the cooling unit is arranged below the reclaimer;

conveying the cooled condensed waste-product from the cooling unit to a receiving tank, wherein the receiving tank is arranged below the cooling unit; and

flowing another new part of heated condensed waste-product from the reclaimer to the cooling unit, thereby enabling the cooling unit to be ready for cooling the new part of heated condensed waste-product,

wherein the cooling is repeated until all the heated condensed waste-product is cooled.

4. The method according to claim 3, wherein the part of heated condensed waste-product is cooled in the cooling unit to a temperature equal to or below 50°

C.