Paraffin Wax Content Research Articles

Optimization of warm mix asphalts using different blends of binders and synthetic paraffin wax contents

In road construction, several processes and products are now available to produce environmentally friendlier warm mix asphalts, including the use of synthetic paraffin wax additives. These additives facilitate the production of energy efficient asphalt mixtures at reduced manufacturing and construction temperatures. However, their sustainability during the road life cycle can only be obtained by optimizing the mixture’s performance. Thus, the objective of this work was to assess the properties of different blends of base bitumens (softer to harder ones) containing a range of synthetic wax contents, as well as the performance of the corresponding warm mix asphalts, that could ultimately lead to more sustainable mixtures. It was concluded that different blends should be selected to maximize the temperature reduction, the fatigue or the rut resistance, without compromising the other properties of the mixture.

Role of polymers in developing phase change materials for energy storage

store energy over longer periods and to effectively release the energy when needed. Research on sensible heat and latent heat phase change materials (PCMs), which started about 20 years ago, still plays an important role in addressing this problem. PCMs absorb and store heat energy when undergoing a solid-solid or solid-liquid phase change. Problems associated with the use of PCMs are their lack of long-term stability, especially under conditions of thermal cycling, the stability of the PCM-container system, and effective heat transfer, because most PCMs have very low thermal conductivity. Apart from a multitude of inorganic materials investigated and commercially used as PCMs in energy storage, commercial waxes and fatty acids were found to be the most promising organic latent heat PCMs. Normally the latent heat of melting method for energy storage is used, but some research focused on the latent heat of solid-solid transitions. Commercial paraffin waxes are cheap with moderate thermal storage densities and a wide range of melting temperatures. They undergo negligible sub-cooling and they are chemically inert and stable with no phase segregation. On the downside they have low thermal conductivity, relative high liquid viscosities, and they are difficult to contain in a certain shape or size. This is where polymers come into the picture. A fair amount of research has been done on the microencapsulation of PCMs by different polymers. Work has also been done on preparing phase change materials consisting of paraffin wax dispersed in a polymer as a supporting material (shape-stabilised PCM). In this case research concentrated mostly on the use of polyolefins. The effective temperature range of such a PCM falls between the melting point of the wax and that of the polymer. It is, however, important that there must be little co-crystallization between the paraffin wax and the polymer. This system has long-term thermal stability under cycling conditions, and the PCM is well contained within the polymer matrix. There are only two persistent problems: low thermal conductivity (which may be overcome by using conductive polymers or by doping) and poor mechanical properties in the presence of high paraffin wax contents.

Encapsulation of phase change materials by complex coacervation to improve thermal performances of woven fabrics

In this study, three types of paraffin waxes suitable for textile applications, namely n-hexadecane, n-octadecane and n-nonadecane were encapsulated through complex coacervation of natural and biodegradable polymers, gum arabic–gelatin mixture, in order to investigate their heat storing or releasing capacities, their durability as well as their practicable thermal performances when integrated into woven fabrics by coating. FT-IR results of capsules have presented the proofs of successful complex coacervation of PCMs. Most of the coacervates withstood considerable centrifugal forces in the leakage test and compression in coating applications of fabrics without resulting in any oil leak. DSC curves taken at 10 °C min −1 and calorimeter measurements at the heating rate of 0.5–1 °C min −1 of coacervates illustrate substantial endothermic enthalpies in the intervals corresponding to the phase transition interval of the paraffin wax used in a particular core, and tend to increase whereas the dispersed PCM contents in emulsions are relatively higher. One of the coacervates of n-hexadecane performed the enthalpy value of 144.7 J g −1, while another coacervate containing n-octadecane provided 165.8 J g −1 and the coacervate including n-nonadecane presented 57.5 J g −1 enthalpy. When coacervates were incorporated with woven fabrics, their feasible thermal performances appeared to be related to both actual paraffin wax content of the coacervate and the incorporation amount of it by the coating application. The energy absorption capacities of the coacervate added fabrics were found to be 2.5–4.5 times enhanced relative to the reference fabric for particular temperature intervals.

Preparation of shape-stabilized phase change materials as temperature-adjusting powder

The shape-stabilized phase change materials (PCMs) composed of paraffin wax and silica were prepared in O/W emulsion with cetyl trimethylamine bromide as emulsifier and n-pentanol as assist emulsifier. The paraffin wax (with melting temperature of 29°C, crystallizing temperature of 26°C and latent heat of 142 J/g) served as latent heat storage material and the silica as supporting material, which prevented the leakage of the melted paraffin wax. Silica supporting material was formed in situ via hydrolysis and condensation from low-cost sodium silicate solution with chlorhydric acid and ammonium bicarbonate as neutralizing agent. The thermogravimetry (TG) curves show that the composite has a thermal stability superior to that of paraffin wax and that the content of paraffin wax in the composite is 65wt%. The maximum latent heat and its relevant melting point of composite are 95 J/g and 30°C, respectively.

In situ dimensional change, mass loss and mechanisms for solvent debinding of powder injection moulded components

Dimensional change during solvent debinding is linked to defects such as cracking and slumping in powder injection moulded components. Owing to the delicate condition of the compact during debinding, considerable difficulty exists in determining the magnitude and cause of swelling or shrinkage. Previous studies of this dimensional change have used measurement techniques involving contact or force on the sample, which may alter the behaviour. This study observes in situ dimensional change during solvent debinding using a non-contact laser dilatometer. Dimensional change was investigated for iron and stainless steel powder injection moulded bars with wax-polymer binders. The effects of solvent temperature, paraffin wax content, paraffin wax density, particle size and solids loading were analysed. Comparisons between the dimensional change and mass loss observations during solvent debinding suggest a relationship between the two phenomena based on soluble polymer swelling.

A geochemical investigation of crude oils from Eastern Pearl River Mouth Basin, South China Sea

A thorough petroleum exploration of the Pearl River Mouth Basin (PRMB), South China Sea, began in 1983. At present, several oilfields have been found in the PRMB, mainly distributed in Dongsha Massif, Huizhou and Xijiang Depressions as well as Huilu Lowhigh, and one of them has been developed recently. The crude oils found in the basin can be classified into two types. One is normal waxy type, and the other is cyclic type, which may be caused by minor biodegration and is restricted to the Liuhua District of Dongsha Massif. However, on the basis of geochemical characteristics, all the crude oils are thermally mature, indicating that they are derived from source rocks which have entered the main oil generation period but their maturity is not high enough to reach the overmature stage. Moreover, in the biomarker distribution, the oils also share many similarities. Almost all the oils contain abundant C 30 4-methylsteranes with 24-ethyl side chain, ubiquitous oleanane and lower concentration of gammacerane, and possess high ratios of Ni/V, pristane to phytane and C 30 hopane over total C 29 steranes as well as high paraffin wax and low sulphur content, indicating that they originated from terrestrial organic matter deposited in lacustrine and marsh coal-forming environments. However, some characteristics resemble Brazilian offshore oils of salinewater lacustrine environment. The oils found in the PRMB can also be classified into three main genetic types based on the relative values of pristane over phytane ratio, C 29 sterane preference and the composition of the carbon isotope. Type I oils occurred in the Huizhou and the Xijiang Depressions and their adjacent Dongsha Massif. It has higher ratios of pristane to phytane (1.80–5.54 and 3.21 on the average scale) and heavier carbon isotopic composition, indicating that their source rocks contain much more abundant terrestrial higher plant input. Type II, encountered in Huilu Lowhigh and its bounding area of Dongsha Massif, has moderate ratios of pristane to phytane (1.78–2.94 and 2.39) and C 29 sterane similar to Type I. Type III is distributed in the Liuhua District of Dongsha Massif and has lower pristane to phytane ratios (ranging from 1.49 to 1.97), smaller C 29 sterane preference, higher C 30 4-methylsterane content and lighter carbon isotopic composition (less than −29%) even though they have undergone minor biodegration, implying that the source rocks of the oils are enriched with lacustrine organism input.

Interpretation of the Geochemistry of Oils of Taranaki and West Coast Region, Western New Zealand

The predominant hydrocarbons produced in the Taranaki Basin are gas condensates, although oil has been discovered at several widespread locations and therefore remains a priority exploration objective. Study of the oil geochemistry by means of bulk chemical characteristics, isotope and biomarker content improves our understanding of their source rocks and maturation histories. Results show that the oils and condensates throughout the region are similar in their bulk chemical character, source environment and levels of maturation suggesting a common source for all the hydrocarbons. The source environments as indicated by biomarkers were terrestrial fresh water swamps with low bacterial anoxic conditions. The primary plant material deposited was vascular plant debris, and onshore in northern Taranaki and in the Murchison Basin, angiosperm debris was an important additional component. These angiosperm indicators are absent from the West Coast and southeastern Taranaki oils and condenstates. The overall environment of the oil sources rocks is similar to that which formed the high volatile coals of the West Coast. These coals, on source rock analyses, also reveal a perhydrous character equivalent to the high hydrogen index normally associated with marine oil source rocks. Maturation levels of the oils, equivalent to a vitrinite reflectance level of Ro 1.0% are indicated by biomarkers. The highest maturation levels reached by drilling so far are 0.9%. suggesting that oil source rocks in Taranaki Basin are at or below the maximum drilled depth of 5.5 km. After generation, the oils of the West Coast were slightly biodegraded as suggested by their low paraffin wax content. However, valid biomarker interpretations for source and maturation conditions are still possible. The widespread occurrences of oil and the consistent nature of the detailed chemistry of the oils suggest that in addition to gas condensate there is a reasonable prospectivity for oil especially in and adjacent to the Central Graben are of the Taranaki Basin and in parts of the West Coast.

Heat stabilisers for PVC

Thermal characterizations of a novel solid fuel for hybrid rocket application, based on the paraffin wax blends with low density polyethylene (LDPE) concentration of 5% (SF-5) and 10% (SF-10) were conducted. Both the increased regression rate in comparison with the polymeric fuel, and the improved combustion efficiency in comparison with the pure paraffin fuel reveal that the blend fuels achieve higher combustion performance. The morphology of the shape stabilized paraffin wax/LDPE blends was characterized by the scanning electron microscopy (SEM). Although the SEM observation indicated the blends have uniform mixtures, they showed two degradation steps confirming the immiscibility of components in the crystalline phase from thermogravimetric analysis (TGA). The differential scanning calorimeter (DSC) results showed that the melting temperature of LDPE in the blends decreased with an increase of paraffin wax content. The decreasing total specific melting enthalpy of blended fuels with decreasing paraffin wax content is in fairly good agreement with the additive rule. In thermomechanical analysis (TMA), the linear coefficient of thermal expansion (LCTE) seems to decrease with an increase of LDPE loading, however, the loaded LDPE do merely affect the LCTE in case of the blends with low LDPE concentration. It was found that a blend of low concentration of LDPE with a relatively high concentration of paraffin wax can lead to a potential novel fuel for rocket application, a contrary case with respect to the field of phase change materials (PCM) where a blend of high concentration of LDPE is usually used with low concentration of paraffin wax.

Calorimetric measurements of paraffin wax in paraffinic transformer oil.

In order to estimate the amount of paraffin wax expected to be precipitated from deep dewaxed paraffinic transformer oil in a temperature range from -50 to -60°C, the paraffin wax was separated by using an urea adducts method, and calorimetric measurements were made of the oil, the wax and the residual oil by use of Differential Scanning Calorimetry (DSC). Adding various amounts of the wax to the residual oil, calorimetric measurements were also made of them. The paraffin wax was also chemically analyzed. Consequently, it has become clear that the paraffin wax content can be estimated roughly by using its heat of fusion and that the pour point of the paraffinic oil specimen seems to be related to the DSC crystallization peak temperature and to the heat of fusion, respectively. Finally, it has been suggested that one may employ this DSC method as one of the excellent methods for estimating paraffin wax content in paraffinic transformer oil.

High-Pour-Point and Asphaltic Crude Oils and Condensates

Summary The production and transportation of oil and gas can be significantly affected by deposition of paraffin and asphaltenes in the reservoir rock tubulars, pumps, vessels, and pipelines. A wide range of solutions has been developed for the operating problems caused by these deposits. Field examples of problems and solutions are cited. Introduction Paraffin and asphaltene control can be expensive and difficult in fields where deposition of these materials is prevalent. The paraffin-deposition problem can vary from very minor to extremely severe depending on the paraffin-wax content of the crude oil, the cloud and pour points of the crude, and the operating temperature. In cases where the paraffin content is high, the paraffin- control costs are significant. In locations where the wax content is much lower, the cost is less, but the problem remains an operating nuisance. Asphaltene problems also vary widely, depending on the crude-oil composition, pressure, and temperature conditions. In the past, asphaltenes have played a significant part in the production history and economics in such instances as the deep horizons (Zone D-7) in the Ventura field, CA. Paraffin problems were reported in tubing, rod pumps, and surface equipment as early as the 1920's. Significant paraffin problems have occurred outside the U.S. in the Shengli area of China, in India, and in Russia. Many devices, chemicals and techniques have been proposed and used, both successfully and unsuccessfully, to treat these problems. Examples of the field problems and the techniques chosen by Shell in the U.S. to combat these problems are cited.. Theory Paraffin Paraffin deposits usually consist of straight- and branched-chain hydrocarbons (usually ranging from C18 H38 to about C40 H82) mixed with other organic and inorganic materials. The paraffin-wax content has been as high as 50% (Altamont, UT) in some crude oils, and as low as 1 % (South Louisiana) in others. The paraffin wax in the Altamont crude has an usually high carbon number (40 to 60). Paraffin solubility in crude oil depends on the chemical composition of the crude oil, pressure, and temperature. Paraffin will begin to crystallize out of solution as soon as the equilibrium temperature and pressure is reached (cloud point). The paraffin deposits will often begin on surfaces cooler than the liquid. The viscosity of the crude oil is increased by the presence of the paraffin crystals and, if the temperature is reduced sufficiently, the crude will become very viscous (pour point). Viscosity vs. temperature curves are shown in Fig. 1 for the Altamont and Michigan crudes. The crude- oil viscosity behaves in a Newtonian manner until wax crystals begin to form (Fig. 1) and, subsequently, as the temperature is lowered, behaves in a non-Newtonian manner. The second deflection in the curve is a result of the large amount of crystals present in the pour-point region of the crude. High-pour-point crude oils generally have pour points in the 60 to 125 deg. F range and may be solid at room temperature (80 deg. F). The cloud point of the Altamont crude is as high as 170 deg. F. The cloud point may be determined by the ASTM D-97-57 method and the pour point by the ASTM D-97-66 method. Test procedures to study effects of dispersants, solvents, and coatings on paraffin deposition have also been describe by Hunt and Jorda. The viscosity of a waxy crude depends on the viscosity of the oil phase and the state of agglomeration of any paraffin-wax crystals present. Fig. 2 is a photomicrograph showing wax-crystal formation in the Altamont crude. The paraffin-crystal agglomeration depends on the quantities of wax crystals and gas present and the mechanical and thermal history of the crude oil. The apparent viscosity of the non-Newtonian oils can be greatly reduced by mechanical shear. The disintegration of large spherical wax agglomerates appears to be the primary cause of the lower apparent viscosity. JPT P. 1192^

The freezing on of zirconium boride thermocouple sheaths

1. The freezing on method of preparation of zirconium boride sheaths is highly promising, and secures blank-shaping properties which are not exceeded by the properties of sheaths made by die extrusion. 2. The best processing characteristics are shown by fine zirconium boride powder slips with 8–10% paraffin wax and 1% of oleic acid, from which it is possible to produce blanks with a packing coefficient of more than 0.6, i.e., one which approaches the theoretical packing coefficient for spherical particles. 3. Mixtures with higher paraffin wax contents do not constitute fully structurized systems, and are subject to layering in the course of time, with the separation of pure paraffin wax on the surface. 4. Blanks frozen on from slips containing a substantial amount of unadsorbed paraffin wax have a low packing coefficient, and their paraffin wax content is higher than the mean paraffin wax content of the slip.

Durability of Blown Asphalt under Accelerate Weathering Test

Thin films (on aluminum panels) of blown asphalt obtained from various crude oils in Middle East mostly, were exposed under Outdoor Test (4 years) and two kinds of Accelerated Weathering Tests. One of the Accelerated Weathering Tests was Light-Water-Refrigeration Test (C Cycle of ASTM Standards), and the other test was Light-Cold Water Test. Softening point, penetration, ductility, flash point, CCl4 soluble matter, evaporation loss, specific gravity, and paraffin wax content (by acetone method) were measured for each sample. By the result of the three methods of the above tests, some relations were observed among the Outdoor Test and the two Accelerated weathering Tests. The rate of acceleration of Light-Cold Water Method was higher than that of C Cycle. The flow of soft samples by the former method was less than that by the latter. When two samples were made from same sources and made by same procedure, higher durability was observed in the one having the greater penetration and ductility or having the lower softening point. No relation was found between wax content (by acetone method) and durability by these tests.In Outdoor Test and Light-Cold Water Method, the higher durability was seen in the thicker film of samples. However, in C Cycle Test, the highest durability was observed when the thickness was 0.8mm, although it showed lower durability for the more thickness.