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Wax deposition is considered one of the most serious operational issues in the crude oil pipelines. This issue occurs when the crude oil temperature decreases below the temperature of wax appearance and paraffin wax starts to precipitate on the pipelines’ inner walls. As a result, the crude oil flow is impeded because of the precipitated wax. The use of polymeric pour point depressants has obtained significant interest among researchers as an approach of wax control for enhancing the flowability of the waxy crude oil. PPD of poly(behenyl acrylate -co-stearyl methacrylate-co- maleic anhydride) (BA-co-SMA-co-MA) was facilely synthesised by the use of free radical polymerisation. The variation of the PPD structure was studied by choosing several essential parameters like monomers ratio, reaction time, initiator concentration, and reaction temperature. Furthermore, viscosity measurement, pour point, and cold finger apparatus have been employed to evaluate the efficiency of the synthesised Polymer. The chemical structure of poly(BA-co-SMA-co-MA) has been identified through the use of Fourier transform infrared as well as nuclear magnetic resonance. The experimental findings demonstrated that the ideal conditions for obtaining the highest yield were 1.5% initiator concentration, reaction time and temperature of 8 h and 100 °C, respectively, and monomer ratio of 1:1:1 (BA:SMA:MA). Under these ideal conditions, the prepared terpolymer reduced the crude oil viscosity at 30 °C and 1500 ppm from 7.2 to 3.2 mPa.s. The cold finger experiment demonstrated that after poly(BA-co-SMA-co-MA) was used as a wax inhibitor, the maximum efficiency of paraffin inhibition of 45.6% was achieved at 200 rpm and 5 °C. Besides, the best performance in depressing the pour point by ΔPP 14 ℃ observed at the concentration of 1500 ppm, which can change the growth characteristics of wax crystals and delay the aggregation of asphaltene and resin, thus effectively improving the flowability of crude oil.

Wax deposition in production pipelines and transportation tubing from offshore to onshore is critical in the petroleum industry due to low-temperature conditions. The most significant popular approach to solve this issue is by inserting a wax inhibitor into the channel. This research aims to reduce the amount of wax formation of Malaysian crude oil by estimating the effective parameters using Design-Expert by full factorial design (FFD) method. Five parameters have been investigated, which are rotation speed (A), cold finger temperature (B), duration of experimental (C), the concentration of poly (stearyl acrylate-co-behenyl acrylate) (SABA) (D), and concentration of nano-silica SiO2 (E). The optimum conditions for reducing the amount of wax deposit have been identified using FFD at 300 rpm, 10 ℃, 1 h, 1200 ppm and 400 ppm, respectively. The amount of wax deposit estimated is 0.12 g. The regression model’s variance results revealed that the R2 value of 0.9876, showing 98.76% of the data variation, can be described by the model. The lack of fit is not important in comparison to the pure error, which is good. The lack of fit F value of 12.85 means that there is only a 7.41% probability that this huge can occur because of noise. The influence of cold finger temperature was reported as the main contributing factor in the formation of wax deposits compared to other factors. In addition, the interaction between factor B and factor C revealed the highest interaction effect on the wax deposition. In conclusion, the best interaction variables for wax inhibition can be determined using FFD. It is a valued tool to measure and detect the unique relations of two or more variables. As a result, the findings of this study can be used to develop a reliable model for predicting optimum conditions for reducing wax deposits and the associated costs and processing time.

Pour point depressants (PPDs) commonly used in the oil and gas industry as a chemical wax inhibitor to control the temperature of the crude oil below their wax appearance temperature (WAT) points, and to improve the flowability of crude oil. In this study, different conditions of Stearyl Acrylate-Behenyl Acrylate (SABA) copolymer were synthesized by free-radical solution polymerization method at different range conditions of polymerization. Four factors considered during the synthesize of the copolymer are the mass ratio of monomers (1:1, 1:2, 1:3, 2:1, and 3:1 wt%), reaction temperature from 60 to 100 °C, the concentration of initiator from 0.5 to 2.5 wt% and reaction time from 5 to 9 hour. The results showed that the best conditions to obtain the highest yield of SABA copolymer were at the mass ratio of monomers of 1:1 (w/w), the reaction temperature of 90 °C, the reaction time of 7 h, and concentration of initiator at 1 wt%.