ENERGY COMPENSATED ENTHALPIMETER FOR PROCESS ANALYSIS

• US 3,768,973 A
• Filed: 04/12/1971
• Issued: 10/30/1973
• Est. Priority Date: 04/12/1971
• Status: Expired due to Term

• Current Assignee: Joseph C. Wasilewski
• Original Assignee: Joseph C. Wasilewski
• Inventors: Wasilewski, Joseph C.
• Primary Examiner(s): Wolk, Morris O.
• Assistant Examiner(s): Serwin, R. E.
• Application Number:
  US05/133,193
• Time in Patent Office: 932 Days
• Field of Search: 23/23A,253A 73/15,190
• US Class Current: 436/147
• CPC Class Codes: G01N 25/48 on solution, sorption, or a chemical reaction not involving combustion or catalytic oxidation
• CPC Class Codes: Y10T 436/15 Inorganic acid or base [e.g. , hcl, sulfuric acid, etc. ]
• CPC Class Codes: Y10T 436/203332 Hydroxyl containing

Abstract

An instrument for determining the concentration of a chemical substance in a moving stream, such as the acid concentration from a metal cleaning process, or other chemical process, present in a flowing process fluid stream, which apparatus measures the heat of reaction of the flowing stream fluid by reacting an aliquot sample of it with a second fluid which is injected into said aliquot sample of the stream under process flow conditions, the instrument being enclosed in a selectively controlled environment. The temperature rise in the aliquot sample and the energy change to a compensating heater are measured with respect to elapsed time, thereby providing two gaussian curves for each aliquot. With the process fluid flushing the analytical cell continuously the net temperature change in the few minutes after reaction is completed in the analytical cell containing the aliquot sample of the process fluid is zero, a new aliquot of process fluid is in the cell, and a second analysis is performed within 1 to 2 minutes, depending on flow time and analytical cell volume.

Claims

2. The enthalpimeter in accordance with claim 1 wherein a flowing chemical process stream is diverted to provide an aliquot of first fluid to said closed cell for analysis therein, and wherein a known analytical reagent is injected into said closed cell as said second fluid.

3. The enthalpimeter in accordance with claim 2 wherein the process stream is known and meets an unknown fluid in said cell.

4. An apparatus in accordance with claim 1 wherein said closed cell can retain an elevated pressure.

5. An enthalpimeter as in claim 1 in which process fluid is conducted continuously into the analytical cell, flushing a prior analyzed aliquot sample and automatically providing a next aliquot sample for analysis.

6. An instrument in accordance with claim 1 for the determination of concentration or heat of reaction of fluid flowing continuously into the cell of the instrument wherein said temperature sensor is a thermistor-heater sensor pair in an electro-mechanical loop control circuit which provides two analytical signals for each analysis, one being a voltage signal Gaussian curve responding to the temperature change and the second being an independent curve of voltage signal responding to the heater energy level.

7. An enthalpimeter for concentration analysis as in claim 1 wherein the analyzing solution flows through the cell continuously and the sample whose concentration is to be determined is the injected sample.

8. An enthalpimeter as in claim 1 in which the injected analytical reagent is a gas.

9. An enthalpimeter in accordance with claim 1 in which the flowing stream is a gas.

10. A process enthalpimeter in accordance with claim 1 for providing a series of Gaussian curves, two for each analysis, which are a measure of the concentration of a chemical substance from a pressure tank or pipe, on a continuous basis wherein the flowing process fluid flushes the cell continuously, and an envelope of the peaks of the Gaussian curves provides a measure of the process fluid concentration changing with time.

11. An enthalpimetric process for measuring the caloric disturbance of a first fluid contained in a closed cell of fixed volume at a given floating energy level which comprises adding a second fluid for reacting the fluid in the closed cell with said second Fluid, sensing the temperature change resulting in the closed cell due to the exothermic or endothermic heat of reaction from the reaction between first fluid in the closed cell and the injected second fluid, compensating the temperature change in the closed cell so that upon completion of the chemical reaction in the closed cell, the closed cell temperature is returned to the original temperature of the fluid in the cell, said second fluid reagent added to the fluid in the cell for reaction therewith being at a preselected controlled temperature, whereby the resulting temperature change and energy change related to time provide two independent bases upon which to determine the heat of reaction of the two fluids, and the concentration of active chemical of said first fluid species in the cell or in the injected reagent.

12. The process in accordance with claim 11 wherein a flowing chemical process stream is diverted to provide an aliquot of first fluid to said closed cell for analysis therein, and wherein a known analytical reagent is injected into said closed cell as said second fluid.

13. A process in accordance with claim 11 for providing a series of Gaussian curves, two for each analysis, which are a measure of the concentration of a chemical substance from a pressure tank or pipe, or a continuous basis wherein the flowing process fluid flushes the cell continuously, and an envelope of the peaks of the Gaussian curves provides a measure of the process fluid concentration changing with time.