Method for measuring the concentration of CaCO.sub.3 in a slurry

• US 4,683,211 A
• Filed: 08/07/1984
• Issued: 07/28/1987
• Est. Priority Date: 08/10/1983
• Status: Expired due to Term

• Current Assignee: Mitsubishi Jukogyo Kabushiki Kaisha
• Original Assignee: Mitsubishi Jukogyo Kabushiki Kaisha
• Inventors: Tatani, Atsushi, Onizuka, Masakazu, Hamada, Takayoshi
• Primary Examiner(s): Lacey, David E.
• Assistant Examiner(s): Hill, Jr., Robert J.
• Application Number:
  US06/638,512
• Time in Patent Office: 1,085 Days
• Field of Search: 436/43, 436/50, 436/51, 436/52, 436/55, 436/79, 436/127, 436/133, 436/146, 436/163, 436/174, 436/175, 436/177, 436/179, 436/181
• US Class Current: 436/50
• 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: G01N 31/00 Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
• CPC Class Codes: Y10T 436/115831 Condition or time responsive
• CPC Class Codes: Y10T 436/117497 with a continuously flowing sample or carrier stream
• CPC Class Codes: Y10T 436/12 Condition responsive control
• CPC Class Codes: Y10T 436/204998 Inorganic carbon compounds
• CPC Class Codes: Y10T 436/235 In an aqueous solution [e.g., TOC, etc.]
• CPC Class Codes: Y10T 436/25125 Digestion or removing interfering materials
• CPC Class Codes: Y10T 436/25625 Dilution
• CPC Class Codes: Y10T 436/25875 Gaseous sample or with change of physical state

Abstract

A method for continuously measuring the concentration of CaCO₃ in slurries comprising CaCO₃ is described. The method comprises continuously sampling a given amount of the slurry, feeding the sampled slurry into an agitated continuous reactor container which is isolated from the outside air, keeping the slurry in the reactor container at a temperature of at least 50° C., adding sulfuric acid or hydrochloric acid to adjust the pH to below 4, blowing a known flow rate of air into the slurry, withdrawing from the reactor container CO₂, produced by the reaction between CaCO₃ and the acid, by entrainment with the air, further mixing the withdrawn gas with air for dilution while controlling a flow rate of the dilution air so that the concentration of CO₂ in the mixed gas is maintained constant, and calculating the concentration of CaCO₃ in the slurry from the concentration of CO₂ in the mixed gas, the flow rate of the mixed gas and the amount of the sampled slurry.

Claims

1. A continuous method for measuring the concentration of CaCO₃ in a slurry containing CaCO₃, the steps consisting essentially of:

continuously sampling a given amount of the slurry;

feeding the sampled slurry at a predetermined flow rate into an agitated continuous reactor container which is isolated from outside air;

maintaining the sampled slurry in the reactor container at a temperature of at least 50°

C.;

adding an acid to the reactor container to adjust the pH of the slurry therein to below 4, said acid reacting with CaCO₃ to form a reaction product and to generate CO₂ ;

blowing a predetermined flow rate of air into the slurry in the reactor container;

withdrawing gas from the reactor container wherein the withdrawn gas comprises the blown air with generated CO₂ entrained therein;

diluting the withdrawn gas with air while controlling the flow rate of the dilution air so that the CO₂ concentration in said diluted withdrawn gas is maintained constant;

determining the flow rate of the diluted withdrawn gas;

passing the diluted withdrawn gas with generated CO₂ entrained therein into a CO₂ analyzer;

measuring the concentration of entrained CO₂ in the diluted withdrawn gas; and

determining the concentration of CaCO₃ in the slurry from the concentration of entrained CO₂ in the diluted withdrawn gas, the flow rate of the diluted withdrawn gas and the flow rate of the sampled slurry, wherein said continuous method is a high speed continuous method capable of measuring the concentration of CaCO₃ in an absorption solution used for pH control of a desulfurization system.

2. The method according to claim 1, wherein the slurry in the reactor container is maintained at a temperature in the range of from 50°

C. to the boiling point of the slurry in the reactor container.

3. The method according to claim 1, wherein the pH of the slurry in the reactor container is adjusted to a value of from 2 to 4.

4. The method according to claim 1, wherein the acid is selected from the group consisting of sulfuric acid and hydrochloric acid.

5. A continuous method for measuring the concentration of CaCO₃ in a slurry containing CaCO₃, the steps consisting essentially of:

continuously sampling a given amount of the slurry;

feeding the sampled slurry at a predetermined flow rate into an agitated continuous reactor container which is isolated from outside air;

maintaining the sampled slurry in the reactor container at a temperature of at least 50°

C.;

adding an acid to the reactor container to adjust the pH of the slurry therein to below 4, said acid reacting with CaCO₃ to form a reaction product and to generate CO₂ ;

blowing a predetermined flow rate of air into the slurry in the reactor container;

withdrawing gas from the reactor container wherein the withdrawn gas comprises the blown air with generated CO₂ entrained therein;

diluting the withdrawn gas with additional air while controlling a flow rate of the dilution air so that the CO₂ concentration in said diluted withdrawn gas is maintained constant;

passing the diluted withdrawn gas with generated CO₂ entrained therein into a CO₂ analyzer;

measuring the concentration of entrained CO₂ in the diluted withdrawn gas; and

determining the concentration of CaCO₃ in the slurry from the concentration of entrained CO₂ in the diluted withdrawn gas, the flow rate of the blown air, the flow rate of the dilution air and the flow rate of the sampled slurry, wherein said continuous method is a high speed continuous method capable of measuring the concentration of in an absorption solution used for pH control of a desulfurization system.

6. The method according to claim 5, wherein the slurry in the reactor container is maintained at a temperature in the range of from 50°

C. to the boiling point of the slurry in the reactor container.

7. The method according to claim 5, wherein the pH of the slurry in the reactor container is adjusted to a value of from 2 to 4.

8. The method according to claim 5, wherein the acid is selected from the group consisting of sulfuric acid and hydrochloric acid.