Method for removing ammonia and carbon dioxide gases from a steam

• US 6,027,552 A
• Filed: 03/30/1998
• Issued: 02/22/2000
• Est. Priority Date: 04/18/1996
• Status: Expired due to Fees

• Current Assignee: Graham Companies Incorporated
• Original Assignee: Graham Companies Incorporated
• Inventors: Ruck, Donald Neal, Tice, David William, Athey, Roderick Elwyn, Lines, James Richard
• Primary Examiner(s): Chiesa, Richard L.
• Application Number:
  US09/050,385
• Time in Patent Office: 694 Days
• Field of Search: 261/97, 261/118, 261/112.1, 261/116, 261/155, 95/211, 95/217, 95/228, 95/229, 95/232, 95/236, 95/238, 95/223, 96/243
• US Class Current: 95/217
• CPC Class Codes: B01D 2257/406 Ammonia
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/002 by condensation
• CPC Class Codes: B01D 53/1431 Pretreatment by other processes
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A method for reducing residual ammonia gas from a steam in a steam condenser. The method includes forming a condensate and a residual gas in a first stage, then forming a condensate curtain in the second stage and passing the residual gas through the condensate curtain prior to exiting the steam condenser. The method may be employed to remove ammonia and carbon dioxide gas from a geothermal steam.

Claims

1. A method of absorbing ammonia and carbon dioxide gases from a steam containing water vapor, ammonia and carbon dioxide gases, comprising:

(a) introducing the steam containing water vapor, ammonia and carbon dioxide gas into a condenser through a vapor inlet;

(b) condensing a portion of the steam to form a condensate and a residual gas containing unabsorbed ammonia and carbon dioxide;

(c) forming a continuous condensate curtain between the vapor inlet and a vapor outlet; and

(d) withdrawing the residual gas through the condensate curtain prior to exiting the condenser.

2. The method of claim 1, further comprising regulating the temperature of the condensate to increase absorption of the ammonia and carbon dioxide gases in the condensate curtain.

3. A method of identifying a first stage of steam condenser to produce a substantially predetermined condensate and a residual gas composition of ammonia and carbon dioxide from a steam containing water vapor, ammonia and carbon dioxide gases, comprising:

(a) specifying an inlet amount of water vapor, ammonia, carbon dioxide and a noncondensable gas;

(b) estimating an amount of the ammonia and carbon dioxide gases unabsorbed by a condensate of the water vapor produced by condensation with a condenser tube in the steam condenser;

(c) determining a corresponding partial pressure of the ammonia and carbon dioxide gases;

(d) calculating the partial pressure of the noncondensable gas based upon the partial pressures of the water vapor, the ammonia, the carbon dioxide and a total specified pressure in the steam condenser;

(e) calculating the amount of noncondensable gas and comparing the calculated amount to the specified amount; and

(f) reiterating steps b-e until the calculated amount of the noncondensable gas substantially equals the specified amount.

4. A method of selecting a first stage in steam condenser for absorbing a predetermined amount of ammonia and carbon dioxide gases from a steam having an initial known concentration of a noncondensable gas, ammonia and carbon dioxide gases, comprising:

(a) estimating the amount of ammonia and carbon dioxide that would be unabsorbed by a condensate of water vapor at a given operating temperature and pressure;

(b) calculating the partial pressures of the unabsorbed ammonia and carbon dioxide in the steam;

(c) calculating the partial pressure of the noncondensable gas in the steam, based on the calculated partial pressures of ammonia and carbon dioxide, the known partial pressure of the water vapor, and the total condenser pressure;

(d) calculating the amount of noncondensable gas in the steam based on the calculated partial pressure of the noncondensable gas;

(e) comparing the calculated amount of noncondensable gas to the known concentration of noncondensable gas;

(f) repeating steps (a-e) until the known amount and the calculated amount are substantially equal to a desired amount; and

(g) selecting a steam condenser having sufficient condensate conditioning surfaces to absorb the ammonia as determined by step f.

5. A method of selecting a first stage in a steam condenser to produce a condensate and a substantially predetermined composition of a residual amount of a first gas from a steam, comprising:

(a) specifying an inlet amount of water vapor, a first gas and a second noncondensable gas;

(b) estimating an amount of the first gas unabsorbed by a condensate of the water vapor produced in the steam condenser;

(c) determining a corresponding partial pressure of the first unabsorbed gas;

(d) calculating the partial pressure of the second noncondensable gas based upon the partial pressures of the water vapor, and the first unabsorbed gas, and a total specified pressure in the steam condenser;

(e) calculating the amount of the second noncondensable gas and comparing the calculated amount to the specified amount; and

(f) reiterating steps b-e until the calculated amount of the second noncondensable gas substantially equals the specified amount of the second noncondensable gas.

6. The method of claim 5, further comprising:

(a) selecting a steam condenser with a condensate subcooling section for conditioning the temperature of the condensate to enhance absorption of a portion of the second noncondensable gas in a second stage of the condenser.

7. A method of reducing the emission of a contaminant gas from a steam containing water vapor and the contaminant gas following condensation of a portion of the steam in a steam condenser, comprising:

(a) forming a continuous curtain of condensate; and

(b) passing the contaminant gas through the condensate curtain to absorb a portion of the contaminant gas before exiting the steam condenser.

8. The method of claim 7, further comprising lowering the temperature of the condensate curtain to increase the absorption of the contaminant gas in the condensate curtain.

9. The method of claim 8, wherein lowering the temperature of the condensate curtain includes subcooling a portion of the condensed steam.

10. The method of claim 7, further comprising forming a substantially closed loop curtain of the condensate to enhance absorption of the contaminant gas.

11. The method of claim 7, further comprising establishing a temperature of the condensate to enhance absorption of the continuant gas in the condensate curtain.

12. A two stage process for removing a contaminant gas from a steam, comprising:

(a) introducing the steam and the contaminant gas into a condenser to form a condensate and a residual gas mixture, the residual gas mixture including the contaminant gas; and

(b) passing the residual gas mixture through a continuous condensate sheet to absorb a portion of the contaminant gas into the condensate sheet.

13. A process for removing a gas from a steam, comprising:

(a) occluding a passage in a condenser from a vapor inlet to a vapor outlet by a continuous condensate curtain;

(b) introducing the steam and the gas into the vapor inlet to form the condensate curtain and a residual gas mixture, the residual gas mixture including the gas; and

(c) passing at least a portion of the residual gas mixture through the condensate curtain to absorb a portion of the gas into the condensate curtain.