Effect of Temperature on Barium Sulfate Scale Inhibition of Diethylene Triamine Penta (Methylene Phosphonic Acid)

Abstract

Laboratory experiments have been carried out to investigate the effect of temperature on the performance of diethylenetriamine penta (methylene phosphonic acid), DETPMP, against barium sulfate scale formation. This paper presents the findings from this recent experimental study. By maintaining both supersaturation and amount of equilibrium precipitation of barium sulfate constant in the test brines, it is found that as temperature increases from 25°C to 60°C, barium sulfate inhibition efficiency of DETPMP decreases considerably. However, as temperature increases further from 60°C to 95°C, the performance of DETPMP remains almost constant. Such phenomena were observed with test brines of different pHs and in absence/presence of hydrogen carbonate. Additional experiments of DETPMP adsorption on barium sulfate reagent powder show that adsorption on barium sulfate continuously increases as temperature rises. This suggests that the adsorption level of DETPMP on barium sulfate surface may not be the key factor in the nucleation inhibition or crystal growth retardation of barium sulfate, when temperature is a variable. Also it is found that for a given supersaturation and a given amount of equilibrium precipitation, the rate of barium sulfate precipitation increases as temperature elevates.