Method and system for determination of starch in a sample

Patent metadata

Field	Value
Publication number	US-12332174-B2
Application number	US-201716089841-A
Country	US
Kind code	B2
Filing date	Mar 24, 2017
Priority date	Mar 31, 2016
Publication date	Jun 17, 2025
Grant date	Jun 17, 2025

Abstract

In a starch concentration measurement, a liquid sample is conducted from a liquid sample such as pulp suspension or filtrate of a paper, board or tissue process. An iodine solution is added to the sample, and a light absorbance or transmittance of the sample is measured at a wavelength longer than about 650 nm, for example longer than about 700 nm. The measured absorbance or transmittance of the sample is converted into the starch concentration of the sample by a predefined correlation between a starch concentration and a light absorbance or transmittance.

First claim

The invention claimed is:

1. A method comprising;
conducting a sample of liquid from a process stream of liquid for online analysis of a starch concentration in the process stream of liquid based on the sample of liquid;
adding iodine solution to the sample of liquid;
measuring a light absorbance or transmittance of the sample of liquid at a wavelength of 650 nm to 900 nanometers where unreacted iodine does not absorb light, after the step of adding the iodine solution;
converting the measured absorbance or transmittance of the sample of liquid into the starch concentration of the sample of liquid by a predefined correlation between a starch concentration and a light absorbance or transmittance;
wherein: the sample of liquid is conducted from a pulp suspension or filtrate in a paper, board or tissue process, and/or the method further comprises controlling a paper board or tissue process utilizing the starch concentration of the sample.

2. The method as claimed in claim 1 , comprising:
separating the sample of liquid into two or more particle populations according to a particle size and or mass before adding the iodine solution;
measuring the light absorbance or transmittance of the sample of liquid for each particle population of the sample of liquid; and
converting the measured absorbance or transmittance of the sample of liquid into the starch concentration of the sample of liquid for each particle population by the predefined correlation between the starch concentration and the light absorbance or transmittance.

3. The method as claimed in claim 2 , wherein the said particle populations comprises:
a population containing a liquid portion of the sample, including the dissolved starch, without particulate matter; and
a population containing particles with absorbed starch.

4. The method as claimed in claim 2 , wherein the one or more particle populations include:
one or more of colloids, fines, fibers, floccules or agglomerates.

5. The method as claimed in claim 1 , comprising:
measuring a light scattering of the sample of liquid before and/or after adding the iodine solution; and
compensating an effect of turbidity of the sample of liquid on the measurement of the absorbance or transmittance based on the light scattering measurement.

6. The method as claimed in claim 1 , comprising:
measuring a light scattering of the sample of liquid before and/or after adding the iodine solution; and
determining a particle count in the sample of liquid based on the measured light scattering.

7. The method as claimed in claim 1 , the method further comprising controlling the paper, board or tissue process utilizing the starch concentration of the sample, wherein the controlling comprises:
one or more of retention control, sizing control, strength control, deposit control or microbe control.

8. The method as claimed in claim 1 , wherein the starch comprises amylose and amylopectin.

9. The method of claim 1 , comprising measuring the light absorbance or transmittance of the sample of liquid at a wavelength of 700 to 900 nanometers.

10. A method, comprising:
conducting a sample of liquid from a process stream of liquid for online analysis of a starch concentration in the process stream of liquid based on the sample of liquid;
adding iodine solution to the sample of liquid;
measuring a light absorbance or transmittance of the sample of liquid at a wavelength of 650 to 900 nanometers both before and after adding the iodine solution to provide two measurements; and
converting a difference between the two measurements of measured absorbance or transmittance of the sample of liquid into the starch concentration of the sample by a predefined correlation between a starch concentration and a light absorbance or transmittance;
wherein: the sample of liquid is conducted from a pulp suspension or filtrate in a paper, board or tissue process, and/or the method further comprises controlling a paper, board or tissue process utilizing the starch concentration of the sample.

11. The method as claimed in claim 10 , comprising:
separating the sample of liquid into two or more particle populations according to a particle size and/or mass before adding the iodine solution;
measuring the light absorbance or transmittance of the sample of liquid for each particle population of the sample of liquid both before and after adding the iodine solution; and
converting a difference between the two measurements of measured absorbance or transmittance of the sample of liquid into the starch concentration of the sample of liquid for each particle population by the predefined correlation between the starch concentration and the light absorbance or transmittance.

12. The method as claimed in claim 11 , wherein the said particle populations comprises:
a population containing a liquid portion of the sample, including the dissolved starch, without particulate matter; and
a population containing particles with absorbed starch.

13. The method as claimed in claim 11 , wherein the one or more particle populations include:
one or more of colloids, fines, fibers, floccules or agglomerates.

14. The method as claimed in claim 10 , comprising:
measuring a light scattering of the sample of liquid before and/or after adding the iodine solution; and
compensating an effect of turbidity of the sample of liquid on the measurement of the absorbance or transmittance based on the light scattering measurement.

15. The method as claimed in claim 10 , comprising:
measuring a light scattering of the sample of liquid before and/or after adding the iodine solution; and
determining a particle count in the sample of liquid based on the measured light scattering.

16. The method as claimed in claim 10 , further comprising:
controlling the paper, board or tissue process utilizing the starch concentration of the sample, wherein the controlling comprises:
one or more of retention control, sizing control, strength control, deposit control or microbe control.

17. The method of claim 10 , comprising measuring the light absorbance or transmittance of the sample of liquid at a wavelength of 700 to 900 nanometers.

Assignees

• Kemira Oyj

Inventors

• Vähäsalo Lari
• Piironen Marjatta
• Joensuu Iiris

Classifications

• G01N2201/121

  Correction signals · CPC title

• G01N2021/8416

  and process controlling, not otherwise provided for · CPC title

• G01N2015/1486

  Counting the particles · CPC title

• G01N33/343

  Paper pulp · CPC title

• G01N21/84

  Systems specially adapted for particular applications · CPC title