Dewaxing
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The experiment aimed to separate wax from crude oil using acetone as a solvent, analyzing samples from Urals and Escravos regions. Results showed that dewaxed crude oil had a lower density and pour point compared to non-dewaxed samples, with Urals containing more wax than Escravos. Dewaxing is crucial in producing lube oils from paraffin base crude oils to improve combustion performance and prevent solidification at high temperatures.
Dewaxing
- 1. Eric Hagenimana February 24, 2015 A00015905 CHE 310 Group 1 members: Immaculata, Kadidjah Crude Oil Dewaxing Abstract The aim of this experiment was to separate wax from crude oil samples by using a solvent extraction method. Acetone was used as solvent in this experiment. Two samples of crude oil from different regions were used, Urals and Escravos crude oil samples. Generally, density of non-dewaxed crude oil was found to be greater than the density of the dewaxed crude oil sample. For example, the density of Ural before dewaxing is 0.835 while the density of Ural after dewaxing is 0.689. Dewaxed crude samples are much lighter than non-dewaxed crude samples. Dewaxed crude sample have lower pour; in this experiment non-dewaxed sample of urals was found to have a higher pour point compared to escravos this due to the fact urals has much wax than escravos. Introduction Dewaxing is a process of removing wax compounds from the desired product of crude oil by introducing a solvent into a petroleum stream. Dewaxing with selective solvents at low temperatures is very important and unavoidable in the production of lube oils from paraffin base crude oils. Petroleum dewaxing is used to extract high molecular weight components, often referred to as waxes, from a petroleum stream. Wax in crude oil cause petroleum products to solidify at higher temperatures. They also can affect the combustion performance of diesel and gasoline fuels. Dewaxing is very important because long-chain n-paraffins ranging from 16–60 carbon atoms in particular (petroleum wax) are responsible for very high pour point of oil and for near-ambient temperature precipitation. Materials and chemicals Urals and Escravos crude oil samples, beakers, acetone, ice water, thermometers, and solvent extractor were used as materials. Procedures First of all, 50 ml of each crude oil sample was measured using a measuring cylinder and poured into a beaker, and then to each of the samples in the beaker, 50 ml of acetone was added. The mixture was allowed to form a precipitate. Afterwards, the beakers were immersed in a mixture of water/ice to see if there will be further precipitation. The residues were filtered off and the
- 2. filtrate collected. The de-waxed oil and the acetone were Separated using a Rotor-vapor at vacuum pressure of 556 mmHg (760 mmHg = 1 atmosphere) and at 40oC. The densities were measured for both the untreated sample and the de-waxed sample. Comparison between the appearances and the densities of the untreated sample and the de-waxed sample was done and tabulated. Finally, the determination of pour points of both dewaxed and untreated samples was performed. Results and Discussion Table of Results and Result Discussions Crude Samples/properties URALS before dewaxing URALS after dewaxing Escravos before dewaxing Escravos after dewaxing Appearance Dark Brown, heavy texture Dark brown, light texture Brown, heavy texture Brown, Light texture Density (g/mL) 0.835 0.689 0.784 0.645 Pour Point 3.7o C - 2o C - As shown in the table above, urals has a higher pour point compared to escravos, and this is because urals contains much wax content. From density, also it is clear that urals is heavier than escravos. The dewaxed samples of both escravos and urals are lighter than their parent samples because the wax was removed. During the pour point determination, both dewaxed samples took longer (many hours) than expected to solidify; that is why their values are not shown in the table. However, based on non-dewaxed samples it can be predicted that dewaxed escravos has a lower pour point compared to dewaxed urals. Conclusion Dewaxing is a process of removing wax compounds from the desired product of crude oil by introducing a solvent into a petroleum stream. Dewaxing with selective solvents at low temperatures is very important and unavoidable in the production of lube oils from paraffin base crude oils. Generally, density of non-dewaxed crude oil was found to be greater than the density of the dewaxed crude oil sample. Dewaxed crude samples are much lighter than non-dewaxed crude samples. Dewaxed crude sample have lower pour compared to non-dewaxed. Reference Petroleum Science Lab Manual Samir, Matar and Lewis .F, Hatch. Chemistry of Petrochemical Process, 2nd Ed.