Patent ID: 6946056
Filing Date: 2005-09-20
Classification: D21C

Abstract:
1. A method for regulating a process for manufacturing paper pulp, where the content of hexenuronic acid in the paper pulp is determined during manufacture of the paper pulp comprising: obtaining a current proportion of the hexenuronic acid in a substance obtained from a process stage, the substance containing at least a portion of pulp fibers that have passed through the process stage; determining the current proportion of the hexenuronic acid by optical spectral analysis by measuring the hexenuronic acid at a first wavelength of about 232 nanometers to obtain a significant value of hexenuronic acid; measuring a second substance at a second wavelength, the second wavelength being different from the first wavelength: correcting the significant value by analyzing optical properties of the second wavelength to obtain a corrected significant value; controlling conditions in the process for manufacturing the paper pulp based on the corrected significant value of the hexenuronic acid; and performing the optical analysis both before and after the process stage, between different measurement points and the change in the intensity in the spectrum around 232 nm between these measurement points or measurement times is used to control conditions in the process stage from which the pulp is obtained.