| US 7,566,571 B2 | ||
| Detection of gels in a solution polymerization | ||
| Yves Lacombe, Calgary (Canada); and Geoffrey Richard Harding, Calgary (Canada) | ||
| Assigned to Nova Chemicals (International) S.A., (Switzerland) | ||
| Filed on Jun. 02, 2005, as Appl. No. 11/143,407. | ||
| Claims priority of application No. 2470887 (CA), filed on Jun. 14, 2004. | ||
| Prior Publication US 2005/0277196 A1, Dec. 15, 2005 | ||
| Int. Cl. G01N 33/44 (2006.01); G05B 21/00 (2006.01) | ||
| U.S. Cl. 436—85 [436/55; 436/171; 700/266; 700/269] | 8 Claims |
| 1. In a solution polymerization process the improvement of detecting the increase in the content of gels having a particle
size from 400 nanometers to 400 microns in the solution at one or more locations comprising the steps of:
(i) at an initial time T1 acquiring an infrared, near infrared or a Raman transmittance or diffuse reflectance spectrum within a wavelength range from
400 to 2,500 nanometers of the solution at said one or more locations;
(ii) at one or more subsequent times Tj wherein j is one or more times after T1 acquiring one or more further infrared, near infrared or Raman transmittance or diffuse spectra within a wavelength range
from 400 to 2,500 nanometers of the solution at said one or more locations;
(iii) using a mathematical method selected from the group consisting of applying a high pass digital filter to the spectrum
taken at Tj or subtracting the Exponential Moving average (EMA) from the spectrum taken at Tj and integrating the resulting spectrum to quantify the noise level; and
(iv) following the general tendency of the noise level over time.
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