Estimation and control of alumina concentration in hall cells
US4814050A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 18, 1987 |
| Grant date | Mar 21, 1989 |
| Priority date | — |
| Expiry date | Nov 18, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25C3/20
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method of estimating and controlling the concentration of alumina in the bath of a Hall cell. The method includes the use of an estimator that employs two sets of equations, namely, a time update algorithm that contains a dynamic model of the alumina mass balance of the cell and provides estimates of alumina concentration, and a measurement algorithm that uses a process feedback variable from the cell to modify the alumina estimate. In addition, the method includes the use of one or more tuning parameters, such as state noise variance and measurement noise variance. The measurement noise variance is modified by the process noise variance in a manner that increases measurement noise variance for high values of process noise and decreases measurement noise variance for low values of process noise. In addition, one or more of the parameters of the model are modified by the feed history of the cell.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.