Test Methods for Determining Asphaltene Stability in Crude Oils

The high cost of remediating asphaltene deposition in crude oil production and processing has necessitated the development of test methods for determining the stability of asphaltenes in crude oils. In the current work, the stability of asphaltenes in crude oils of varying API gravity is predicted using the Oliensis Spot Test, the Colloidal Instability Index, the Asphaltene-Resin ratio, and a solvent titration method with NIR solids detection. The test methods are described in detail and experimental data from them presented. The experimental stability data were validated via correlation with field deposition data. The effectiveness of the various tests as predictors of the stability of asphaltenes in oils is discussed. The Colloidal Instability Index and the solvent titration method were found to predict a crude oil's propensity towards asphaltene precipitation better than both the Asphaltene-Resin ratio and the Oliensis Spot Test. For oils with low asphaltene content where most stability tests fail, live oil depressurization is proposed as the test for predicting the stability of asphaltenes.     

机场沥青的技术要求与标准

机场道面和公路路面处于不同状态下工作。用于机场道面的沥青材料应是优质沥青，并且符合机场沥青的技术要求。此外，本文还对优质沥青的生产、市场等问题进行了讨论。     

季铵盐型阳离子沥青乳化剂的合成及影响因素研究

采用某酚、环氧氯丙烷、三乙胺同时加料的方法合成了季铵盐型阳离子沥青乳化剂，对合成的轧化剂轧化沥青的性能进行了测试。重点研究了溶剂、反应温度、反应时间对该合成反应的影响，并确定了最佳反应条件为甲醇和水的混合溶剂为较适宜的溶剂；最佳的反应温度为70C；反应时间4h为宜。     

A SAPONIFICATION CYCLE FOR SOLVENT RECOVERY FROM SAND SURFACES FOLLOWING BITUMEN EXTRACTION

A saponification cycle utilizing a fatty acid/heptane solvent blend was studied as a method for removing solvated bitumen from sand surfaces in a tar sands processing unit prior to disposal of the tailings. In this process, the fatty acid portion of the solvated bitumen was saponiffied with caustic resulting in an in-situ soap which aided in washing the organics off the sand surfaces. The wash liquid was then desaponified with hydrochloric acid to reconstitute the fatty acid, which went into the organic phase with the bitumen and heptane. This solvated bitumen stream was processed by an amphiphilic phase shift reaction to separate out the bitumen and recover the solvent for recycling back to the contactor. The aqueous phase from the desaponifier is brine and must be discarded. The saponification/desaponification kinetics and the phase behavior of this cycle were investigated as they apply to this process. Saponification cycle experiments showed that the fatty acid portion of the solvent could by fully recovered and used repeatedly. Bench-scale washing experiments showed that this saponification cycle promoted the removal of the viscous, solvated bitumen from sand surfaces.     

Rheological modification of bitumens with new poly-functionalized furfural analogs

The rheological properties of bitumens modified with different aldehydes show that furfural is a very efficient reagent. An optimization of the reaction conditions involving concentration, acid catalyst, reaction time and temperature has been performed. In order to determine the influence of the furan ring and the formyl groups on the reactivity of bitumens, a series of new organic molecules as chemical reagents bearing up to six furan rings and four formyl groups, have been reacted with a B 80/100 bitumen. The results indicate a remarkably better performance than furfural, leading to harder modified bitumens.     

放射性化学沉淀泥浆水泥固化研究

本文探讨了用水泥同化放射性化学沉淀泥浆的可行性,研究了同化工艺配方和固化物的浸出性能。固化试验结果表明,固化体中添加20%斜发沸石可提高固化体的抗压强度,降低固化体中~(137)Cs 的浸出牢;固化体上表面复盖3mm 厚的沥青浸泡1066d,铯累积浸出分数仅6.87×10~(-2)cm;固化体外表面包复薄层沥青后,铯累积浸出分致更低,仅9.12×10~(-5)cm。     

The steric hardening and structuring of paraffinic hydrocarbons in bitumen

The formation of ordered structures of macro- and microcrystalline waxes during cooling from the melt of bitumen was observed using temperature-modulated differential scanning calorimetry. This process develops in time. It is found that steric hardening of bitumen (gradual hardening at room temperature) is related to the processes of formation of ordered structures of bitumen waxes.     

The effect of asphaltene on thermal properties of bitumen

Chemical composition and any variation of four main components of bitumen (asphaltene, saturated, naphthene aromatic and polar aromatic) have effective impact on its properties and especially, thermal properties. In other words, in order to have asphalt pavements with reasonable temperature susceptibility and thermal stability, first of all it is essential to know the effect of these components on bitumen properties. Therefore, in this research these effects were investigated and it was found that penetration index (PI) and penetration viscosity number (PVN) of bitumen were increased with increasing in asphaltene content.Thermal behavior of bitumen in an oxidizing environment was also studied using thermogravimetric analysis (TGA) technique. The results showed that increasing the asphaltene content of bitumen decreases the temperature susceptibility and improves the resistance of samples to thermal decomposition.     

Influence of the processing conditions on the rheological behaviour of polymer-modified bitumen

Mixing polymers into bitumen has important consequences on the engineering properties of bituminous binders. Thus, structural and chemical changes may be observed during processing of polymer-modified bitumens. Chemical compatibility and processing conditions are crucial to obtain suitable properties. Most polymers occur to be insoluble, in some degree, in the bitumen matrix, and phase separation may result. Polymer stabilization can be achieved by mechanical dispersion of the modifier and swelling by compatible components in the maltene fraction. This paper deals with the influences that processing variables exert on the rheological properties of polymer-modified bitumens. From the experimental results obtained we may conclude that a rotor-stator mixer device enhances the rheological properties of binders prepared with high-density polyethylene, low-density polyethylene, ethylene-propylene-diene monomer, and their blends, as compared to a stirred tank device.     

Oxidized rapeseed oil methyl ester as a bitumen flux: Structural changes in the ester during catalytic oxidation

Structural changes occurring in the rapeseed oil methyl ester upon catalytic oxidation at 200 °C were examined. Oxidative decomposition of fatty acid chains to lower molecular weight compounds and the formation of oligomers were the major oxidation pathways at 200 °C. FT-IR and ¹H NMR examinations, as well as the fall in iodine number, revealed the disappearance of double bonds. Quantitative analysis of the rapeseed oil methyl ester and the liquid products of its oxidation showed that oxidation of fatty acid methyl esters possessing three and two double bonds was practically complete whereas for structures possessing one double bond the loss of unsaturation amounted to 25% only. The decrease in iodine number from about 110 to about 65 and the 1.5-fold increase in molecular weight of the liquid products in the course of 25-h oxidation suggest that only a part of the unsaturated bonds in the fatty acid methyl ester was engaged in the formation of liquid oligomers and volatile oxidation products. The addition of dicumyl peroxide promoted the formation of organic peroxides during the initial stage of oxidation, which resulted in a higher molecular weight of the liquid products. The volatile oxidation products were found to contain lower molecular weight aldehydes, ketones, free fatty acids and their methyl esters, alkylfurans, lactones, n- and isoalkanes. The reaction schemes for their formation were presented. The results of the study are of importance to the optimization of the conditions for oxidation of the ester in order to obtain a quality ecological bitumen flux.