A Comparative Study of the Effectiveness of Selected Chemical Inhibitors for Wax Control

Abstract Wax deposition in crude oil pipelines is a pervasive issue that significantly impacts the efficiency and safety of oil transportation. This paper presents a comprehensive comparative study of the effectiveness of two chemical inhibitors—n-hexane and methyl ethyl ketone (MEK)—in mitigating wax deposition. The experimental design employed a Taguchi orthogonal array to systematically investigate the effects of four critical factors: temperature, contact time, solvent volume, and wax mass on the dissolution efficiency of each solvent. The dissolution efficiency was measured as the primary response variable to assess the performance of the inhibitors. The crude was characterized for its physicochemical properties, including wax content, viscosity, density, pour point, and cloud point in order to understand the crude oil's behavior and interaction with the inhibitors. Design Expert was used for experimental design and analysis of variance (ANOVA) to determine the statistical significance of each factor and their interactions on the dissolution efficiency and identification of optimal conditions for each solvent. Matlab was used to generate main effects plots that elucidated the influence of each factor on the solvent efficiency. The ANOVA results indicated that temperature and solvent volume were particularly significant factors. The optimal temperature for wax dissolution with n-hexane was 25°C, contact time of 20 minutes and solvent volume of 60 ml. The effect plots show that for n-hexane solvent efficiency was maximum at 25°C, optimum contact time was 15 minutes, solvent volume of 60 ml and increasing efficiency with decreasing mass of wax. The findings confirmed n-hexane as the most effective solvent having 95.67% solvent efficiency and a mean of 66.34% for the 9 runs while MEK was 36.93%. This study concludes that, under ideal circumstances, n-hexane is preferable to MEK for the breakdown of wax.