Determination and control of effective alkali in kraft liquors by IR spectroscopy
US5282931A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 8, 1992 |
| Grant date | Feb 1, 1994 |
| Priority date | — |
| Expiry date | Jul 8, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N33/34
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A direct monitoring and control method is provided for on-line measurement of effective alkali, carbonate, sulfate and thiosulfate concentrations in process liquors for the production of kraft pulp. The control method eliminates frequent sampling, and the need for frequent equipment maintenance. The method includes the steps of withdrawing samples of a liquor from the kraft manufacturing process, subjecting the samples to infrared spectrophotometry at predetermined wave numbers to produce peak-absorbance measurements relative to a background spectrum of water, determining peak absorbance for different alkali concentrations, correlating relationships between the peak-absorbance measurements of samples with the peak absorbance for different alkali concentrations to determine optimum effective alkali in the samples, and controlling at least one process parameter to obtain effective alkali of the liquor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.