Sea water desalination using CO2 gas from combustion exhaust

• US 6,180,012 B1
• Filed: 03/19/1997
• Issued: 01/30/2001
• Est. Priority Date: 03/19/1997
• Status: Expired due to Fees

• Current Assignee: Enpro AS
• Original Assignee: Paul I. Rongved
• Inventors: Rongved, Paul I.
• Primary Examiner(s): Hruskoci, Peter A.
• Application Number:
  US08/816,792
• Time in Patent Office: 1,413 Days
• Field of Search: 210/702, 210/710, 210/712, 210/717, 210/718, 210/723, 210/724, 210/726, 210/738, 423/429, 423/470, 423/471
• US Class Current: 210/717
• CPC Class Codes: B01D 2251/304 of sodium
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: C02F 1/52 by flocculation or precipitation of suspended impurities C02F1/463 takes precedence
• CPC Class Codes: C02F 2103/08 Seawater, e.g. for desalination
• CPC Class Codes: C02F 2301/08 Multistage treatments, e.g. repetition of the same process step under different conditions
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

The invention relates to desalination of Sea water and of brakish water, and removal of harmful CO₂ gas in exhaust from combustion apparatuses. The exhaust, rich in carbon dioxide (CO₂) is diverted to a process chamber, where Sea water, after being mixed with Ammonia, as a catalyst to weaken the salt molecules, is pumped into the chamber and dispersed at many points near the top, as a fine spray, exposing the salt to the CO₂ gas there. The internal bond of the salt molecules (NaCl) are weaker by the Ammonia in the water attaching and pulling on their Cl atom. The CO₂ in the chamber is attaching and pulling on the Na atom of the salt molecules and are further reduces the bond, breaking them apart. Two heavy solids are formed, they settle in a clarifier below and are removed. Desalinated Sea water, in large quantities per ton of salt, over flows from the clarifier, for use in communities and for agriculture. Therewith is also harmful CO₂ in the exhaust removed, before being discharged from the process chamber to the sky. The solid NH₄Cl can be recycled for Ammonia, and the second solid Na₂CO₃ is a saleable product, which may more than pay for the process.

Claims

1. A process for desalination of Sea or brackish water, comprising mixing ammonia (NH₃) into said water to form an effective amount of ammonium hydroxide (NH₄OH) to react with NaCl salt molecules present in said water and weaken the NaCl bonds in said molecules;

spraying said water as a fine spray near the top of an enclosed process chamber;

exposing the sprayed water to an effective amount of CO₂ combustion exhaust gas to react with said salt molecules and form sodium carbonate (Na₂CO₃) and ammonium chloride (NH₄Cl) solids;

settling said solids in a clarifier below said process chamber;

removing said solids through an underflow outlet in said clarifier;

discharging exhaust gas from said process chamber; and

removing desalinated water as an overflow from said clarifier.

2. A process as in claim 1, wherein said process chamber is provided with splash boards to catch and splash the water for addition salt removal.

3. A process as in claim 1, wherein said water has a maximum salt concentration of 22 percent.

4. A process as in claim 1, wherein said process is performed in two or more chambers arranged in tandem or parallel.