Precipitation of Chromium Acetate Solutions
| Autor: | C.S. McCool, Don W. Green, M.J. Michnick, G.P. Willhite, Bin Zou |
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| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | SPE Journal. 5:324-330 |
| ISSN: | 1930-0220 1086-055X |
| Popis: | Summary Chromium(III)-polymer systems are often used in permeability modification treatments. The transport of chromium(III) in-depth in porous rocks is sometimes limited due to precipitation. Precipitation is caused by the increase in the solution pH because of fluid-rock interactions, particularly in carbonate rocks. This paper presents experimental data on the rate of precipitation of chromium from chromium(III) acetate solutions. Experimental data were obtained for the precipitation of chromium from chromium acetate solution at constant pH. Data were obtained as a function of pH, temperature, salinity, and OAc/Cr mole ratio. The pH range studied was between 7 and 10, and the temperature range was between 25 and 45°C. Precipitation of chromium was preceded by an induction period where there was no change in concentration. The induction period decreased from 1,200 minutes at pH 7 to less than 200 minutes at pH 10 at 25°C. A higher temperature increased the precipitation rate. Precipitation is delayed by the addition of acetate ion. Both the salinity and salt type have significant effects on the rate of precipitation. A kinetic model was developed to describe both the induction period and the rate of precipitation of chromium from a chromium acetate solution in 1% KCl at 25°C for a pH range of 7 to 10 with OAc/Cr mole ratios between 3 and 9. |
| Databáze: | OpenAIRE |
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