Effect of Metal Ions and Compounds on the Rheological Properties of a Drag-Reducing Cationic Surfactant Solution Exhibiting Shear-Induced Structure Formation
✍ Scribed by Yuntao Hu; Eric F. Matthys
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 199 KB
- Volume
- 186
- Category
- Article
- ISSN
- 0021-9797
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✦ Synopsis
drag-reducing ability after a period of continuous circulation. The effect of various metal ions and compounds on the viscoelas-The effective time varied from a few days to tens of days, ticity of a 12.5/5 m M sodium salicylate (NaSal)/tris(2-hydroxydepending on the components present in the loop. This type ethyl) tallowalkyl ammonium acetate (TTAA) surfactant solution of loss appears to be ''permanent'' and does not recover has been studied phenomenologically. This solution normally exafter rest, in contrast to the temporary loss of drag reduction hibits shear-induced structure formation and strong drag reducdue to the reversible micellar structure breakdown under tion properties. The viscosity and N 1 buildup times under a conhigh stress. This apparently permanent loss of drag reduction stant shear rate increase monotonically with the concentration of could be due a priori either to mechanical degradation as in added Zn(OH) 2 , Cu(OH) 2 , or Fe(OH) 3 . The magnitude of N 1 and the viscosity do not change significantly with the addition of the case of polymeric drag reducers or to chemical degrada-Zn(OH) 2 , but decrease dramatically with increasing Cu(OH) 2 , tion. Subsequent experiments indicated, however, that the Cu 2 (OH) 2 CO 3 , and Fe(OH) 3 concentrations. The effect is believed effective lifetime of the surfactant solutions appears to deto be due to adsorption on insoluble particulates and to reaction pend strongly on the materials the components in the test between copper compounds and NaSal. Mg 2/ and Cu 2/ do not loop are made out of, but is independent of the pump speed. change the steady-state viscosity and N 1 , whereas Na / , Zn 2/ , and The loss of drag reduction for surfactant systems was there-Ca 2/ decrease these quantities significantly at low shear rates. The fore suspected to be due mainly to the presence of chemicals loss of viscoelasticity in the NaSal/TTAA solution due to Cu(OH) 2 generated by the corrosion of the loop components rather and Cu 2 (OH) 2 CO 3 can be recovered, however, by adding the chethan to mechanical degradation. This was also suggested by lating agent ethylenediaminetetraacetate to the contaminated sothe incomplete recovery of drag reduction on addition of lution. The rheological results are consistent with drag reduction experiments. The results show that chemical contamination may surfactant or counterion (2).
be an important issue for drag-reducing cationic surfactant addi-A typical hydronic heating or cooling system consists of tives used in industrial applications where such contaminants are steel, copper, and brass. These materials can undergo corropresent. ᭧ 1997 Academic Press sion with time and generate various chemicals (3, 4). The Key Words: surfactant; cationic; metal; hydroxide; rheology; predominant corrosion products released by a steel pipe are drag reduction; salts.
ferrous ions, Fe 2/ , and ferric hydroxides, Fe(OH) 3 . The presence of these contaminants was indeed suspected in the drag-reducing surfactant solution after a period of circulation