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

• US 4,677,077 A
• Filed: 08/07/1984
• Issued: 06/30/1987
• Est. Priority Date: 08/10/1983
• Status: Expired due to Term

• Current Assignee: Mitsubishi Jukogyo Kabushiki Kaisha (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Jukogyo Kabushiki Kaisha (Mitsubishi Heavy Industries, Ltd.)
• Inventors: Okino, Susumu, Kono, Susumu, Onizuka, Masakazu
• Primary Examiner(s): Lacey, David L.
• Assistant Examiner(s): Hill, Jr., Robert J.
• Application Number:
  US06/638,574
• Time in Patent Office: 1,057 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 air into the slurry in the reactor container, withdrawing from the reactor container CO₂, produced by the reaction between CaCO₃ and the acid, by entrainment with the air, and calculating the concentration of CaCO₃ in the slurry from the concentration of CO₂ in the withdrawn gas, the amount of the sampled slurry and the flow rate of the blown air.

Claims

1. A method for continuously measuring the concentration of CaCO₃ in a slurry containing CaCO₃ which is used in flue gas desulfurization systems using a wet lime process, 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 having a bottom and which is isolated from outside air;

keeping the 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;

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

withdrawing gas from the reactor container wherein the withdrawn gas comprises the blown air with CO₂ produced by a reaction between CaCO₃ and the acid entrained therein measuring the concentration of CO₂ in the withdrawn gas; and

calculating the concentration of CaCO₃ in the slurry from the CO₂ concentration in the withdrawn gas, the flow rate of the sampled slurry, and the flow rate of said blown air.

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

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

4. 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.

5. The method according to claim 1, wherein the blown air enters the reactor container from the bottom of said reactor container, dilution air is added to the withdrawn gas at a predetermined flow rate prior to the step of measuring the CO₂ concentration in the withdrawn gas, and wherein the calculating step comprises calculating the concentration of CaCO₃ in the slurry from the CO₂ concentration in the withdrawn gas, the flow rate of the sampled slurry, the flow rate of the blown air and the flow rate of the dilution air.