Comparison of pour point depressant (PPD) ethylene-vinyl acetate (EVA) and nano-montmorillonite

One of the problems with oil production is stuck of oil transportation flow in the pipeline caused by wax deposits. The high wax content in crude oil causes the oil viscosity value to increase so that crude oil has High Pour Point Oil (HPPO) properties. In this research, using crude oil sample with initial pour point of 31oC and viscosity of 556 cP. This samples are classified as heavy oil. Therefore, this sample is suitable for use as an experiment in this research. There are several methods to deal with HPPO. One chemical method used to overcome this problem is adding Pour Point Depressant (PPD) to crude oil. This PPD functions to decrease pour point value by binding wax crystals in crude oil. In this study, two types of PPD were compared, Ethylene-Vinyl Acetate (EVA) and Nano-Montmorillonite (Nano-MMT). Both can reduce the pour point value on crude oil, but PPD EVA shows a more excellent reduction than nano-MMT. The results show that EVA is better at binding crystals than nano-MMT. After the injection of 400 ppm EVA, the pour point value of crude oil could be decreased up to 24oC, and the viscosity also decreased by 185 cP.

Methcyclohexyl methacrylate-methacrylate copolymers：An effective cold flow improver for the biodiesel blends

The poor cold flow property is one of the main obstacle factors in affecting the utilization of high-proportional biodiesel blends in engines. In this study, methcyclohexyl methacrylate-methacrylate copolymers (MCHMA-R1MC, R1 = C12, C14, C16, C18) were synthesized at various molar ratios by radical polymerization and characterized by FTIR, GPC, and 1H NMR. Their structures and properties areanalyzed and characterized by FTIR, GPC, and 1H NMR. The resulting copolymers were tested as the cold flow improver in terms of cold filter plugging point (CFPP) and solid point (SP) measurement for treated and untreated B20 biodiesel blends (20 vol.% biodiesel + 80 vol.% diesel). Results showed that the CFPP and SP of B20 decreased to a varied extent after MCHMA-R1MC treatment. When the monomer ratio of is 1:7, MCHMA-C14MC (1:7) proved the greatest depression in CFPP and SP of B20 by 18 and 25℃ at 2000 ppm dosage. The effects of MCHMA-R1MC copolymers on crystal behavior was studied through polarizing optical microscope(POM), differential scanning calorimetry(DSC) and viscosity-temperature curves. The results indicated that MCHMA-C14MC could effectively delay the aggregation of wax crystals and change their crystalline behavior by changing the shape of the crystals and inhibiting the formation of large wax crystals, and then lower the low-temperature viscosity of biodiesel blends and make it exhibiting better cold flow properties.

Experimental Measurements of Wax Precipitation Using a Modified Method of Simultaneous Centrifugation and High-Temperature Gas Chromatography

Wax precipitation and deposition are serious flow assurance problems. Wax precipitation is investigated simultaneously using centrifugation and high-temperature gas chromatography (C-HTGC) to obtain the amount and component distribution of precipitated wax in artificial waxy oil and diesel at different temperatures. However, the conventional C-HTGC method gives upper measurements of the amount of precipitated wax, as it ignores wax dissolved in crude oil in the centrifugal cake. A modified C-HTGC method was developed to obtain the precipitated solid fraction of crude oil, based on the mass balances of the non-crystallized fraction of the centrifuged cake. The weight, percent and carbon number distribution of precipitated solid wax crystals at different temperatures of artificial oil and 0# diesel were obtained. It was found that wax precipitation characteristics are affected by many factors, including the carbon number distribution of the oil, the sensitivity of alkane crystallization to temperature and the temperature of the waxy oil solution. The average carbon number of alkanes in precipitated wax crystals decreases with the decrease in temperature. The distribution of alkanes in solid wax crystals is roughly the same as that in 0# diesel but slightly heavier than in diesel. Alkanes with high carbon numbers precipitate simultaneously with those with low carbon numbers.

Molecular dynamics simulation of waxy deposition in crude oil system

Understanding the phase transition and deposition behavior of crude oil system with waxy is of great significance to ensure the safe production and transportation of oil. In this paper, molecular dynamics simulation is employed to explore the deposition process of crude oil system with heterogeneous waxy on the solid surface. The results show that in a multiphase system, the morphology of paraffin wax crystals will change correspondingly at different system temperatures. At low-temperature, the paraffin molecules are arranged in an orderly manner, which are easier to form wax crystals, resulting in the density of the system that changes greatly. As the temperature increases, the aggregation of the wax molecules decreases, which makes the fluidity increase, and it is not easy to form wax crystals.

Flow behaviour of water-in-oil emulsions stabilized by wax crystals

The large temperature gradients experienced by crude oil emulsions in pipelines found in colder environments can lead to the precipitation, deposition and build-up of wax-like species from the crude oil onto the pipe wall that result in flow assurance problems. The objective of this thesis was to understand the rheological behaviour of model water-in-oil emulsions stabilized by wax crystals. The microstructure, phase transitions and rheology of model emulsions constisting of water, mineral oil, parrafin wax and the emulsifier polyglycerol polyricinoleate (PgPr) were investigated. Changes in emulsion flow begaviour (steady state and dynamic) as a function of composition, termperature and passage through a laboratory-scale flowloop were investigated, with these parameters significantly affecting shear flow, yield stress and viscoelasticity. The gelation temperature of wax-containing ('waxy') oil was slightly lower than that of its equivalent emulsion due to differences in the structure of the gelled emulsion network. Overall, this study successfully showed that there exist significant differences in the microstructure and flow behaviour of model crude oil emulsions when wax and a dispersed aqueous phase are present.

Flow behaviour of water-in-oil emulsions stabilized by wax crystals

The large temperature gradients experienced by crude oil emulsions in pipelines found in colder environments can lead to the precipitation, deposition and build-up of wax-like species from the crude oil onto the pipe wall that result in flow assurance problems. The objective of this thesis was to understand the rheological behaviour of model water-in-oil emulsions stabilized by wax crystals. The microstructure, phase transitions and rheology of model emulsions constisting of water, mineral oil, parrafin wax and the emulsifier polyglycerol polyricinoleate (PgPr) were investigated. Changes in emulsion flow begaviour (steady state and dynamic) as a function of composition, termperature and passage through a laboratory-scale flowloop were investigated, with these parameters significantly affecting shear flow, yield stress and viscoelasticity. The gelation temperature of wax-containing ('waxy') oil was slightly lower than that of its equivalent emulsion due to differences in the structure of the gelled emulsion network. Overall, this study successfully showed that there exist significant differences in the microstructure and flow behaviour of model crude oil emulsions when wax and a dispersed aqueous phase are present.

A Double-Edged Sword of Surfactant Effect on Hydrophobic Surface Broccoli Leaf as a Model Plant: Promotion of Pathogenic Microbial Contamination and Improvement to Disinfection Efficiency of Ozonated Water

Pathogenic microbial contamination is significantly influenced by the crop surface properties and surfactant use, which are crucial factors for the postharvest washing process. However, there is little information on the interaction between surfactant and food pathogens on food crops. Thus, this study (1) investigated whether the attachment of Salmonella increases as pesticides denature epicuticular wax crystals and (2) tested if the antibacterial effect of ozonated water can be improved on waxy produce surfaces by adding surfactant to ozonated water. As a result, significantly lower levels of Salmonella Typhimurium attached to waxy leaf surfaces than they did to glossy and pesticide-treated waxy leaf surfaces (3.28 as opposed to 4.10 and 4.32 Log colony forming units (CFU)/cm2, respectively), suggesting that the pesticide containing a surfactant application increased the attachment of S. Typhiumurium on waxy leaf surfaces. There was no significant washing effect on waxy leaf surfaces washed with ozonated water. On the other hand, S. Typhimurium were not detected on waxy leaf surfaces after washing with surfactant-added ozonated water.