Papers by Keyword: Dehydration

Abstract: One of the emerging alternatives to surfactants in crude oil dehydration is the application of nanoparticles. This review aims to assess the recent progress in the application of nanoparticles for the chemical demulsification of water-in-oil and to provide knowledge gaps for future research. This review covers the nanomodification of commercial demulsifiers and the demulsification performance of magnetic and nonmagnetic nanoparticles, along with their possible mechanisms and factors that affect their dehydration efficiency. The addition of nanoparticles improves the dehydration performance of commercial demulsifiers by improving their wettability and interfacial activity. The advantage of magnetic nanoparticles is their rapid response to a magnetic field, which allows them to be recoverable. For nonmagnetic nanoparticles, their advantage is their environmental friendliness, biocompatibility, and cost-effectiveness. Nanoparticles were able to dehydrate emulsions by modifying the interfacial properties and possibly through adsorption of asphaltenes. Factors such as dosage, temperature, pH, salinity, water content, surfactant concentration; and nanoparticle wettability, and surface chemistry significantly affect the demulsification performance. The application of nanoparticles as demulsifiers is still on a laboratory scale. However, studies on toxicity and proper handling may increase interest for field application. Studies are encouraged on the exact mechanism on the reduction of interfacial tension.

Abstract: The issue of dewatering sand, which is used in construction as an aggregate for heavy, simple, fine-grained, large-cell and silicate concrete, concrete mixtures, in the manufacture of reinforced concrete structures, in the production of asphalt and road surfaces, roofing construction materials, in the manufacture of glass, is considered. The results of experimental studies of the operation modes of the process of dewatering construction sand at drainage warehouses with the use of vacuum units are presented, depending on the time of its dewatering, the granulometric composition of the sand, and the placement scheme of special needle filter elements of the suction system.

Abstract: Experimental studies of some physical properties of paulownia wood and identifies differences in comparison with other popular species are presented. In particular, the regularities of hydration and dehydration processes were investigated. Based on the results obtained, reliable data on the hygroscopic properties of paulownia were obtained for the first time. It was found that the hydration rapidity of paulownia (V_pl = 1.493) exceeds the similar rate of pine (V_pn = 1.1313) at a temperature of 20 °C. Changing the temperature of the liquid in which the wood is modified leads to an increase in the impregnation rapidity and, therefore, increases the productivity of the process. The dehydration rapidity of both species is almost the same (k = –0.002), which allows them to be dried simultaneously in the same chamber, optimizing production logistics. The dependence of liquid absorption on concentration was investigated. It has been found that a higher concentration outside causes a greater diffusion flux into the sample, while a higher concentration inside leads to a decrease in the sample weight. During the hydration stage, the weight of paulownia samples increased by 4 times, and pine samples – by 2.5 times. A two-stage kinetic model of wood hydration has been developed, which adequately describes the dynamics of the process. The resulting S-shaped curve clearly characterizes the features of the kinetics processes with saturation. Verification showed a high correlation – 85 % – for hydration and over 90 % for dehydration, which allows for accurate modeling and prediction of the technological processes of wood impregnation and drying.

Abstract: The monooxidation of methane into methanol was carried out on biomimetic heterogeneous catalyst – iron pentafluorotetraphenylporphyrin on Al₂O₃ (ImtOH), at atmospheric pressure and temperatures of 200-350°C, which resulted in liquid one-carbon compounds CH₃OH (19.2%), CH₂O (1.55%), CH₃OCH₃ (8.2%) with high selectivity and are widely used in the chemical industry. In order to establish the routes of these products formation and the mechanism for the methane conversion into them, the investigation of the methanol conversion reaction was carried out, as an intermediate compound of the methane oxidation, under identical conditions on the same catalyst.The result was only dimethyl ether with 100% selectivity. This proved that in this reaction system, methanol obtained from the methane monooxidation is converted only into dimethyl ether, and formaldehyde, in parallel with methanol, is formed from methane. The mechanisms of the elementary stages of the formation of methanol, formaldehyde and dimethyl ether on the surface of the bioimitator through the formation of an active complex (ImtOOH) are presented, in which the unity of the mechanisms of redox and acid-base catalysis traced within the framework of the principle of the bond redistribution chain (BRC), similar to enzymatic reactions.

Abstract: The issue of moisture content of sand, which is used in construction as an aggregate for asphalt concrete mixtures, in the production of silicate building materials, roofing roll materials, and various types of glass, is considered. The results of an experimental study of the process of dewatering construction sand samples in conical warehouses under the conditions of using vacuum systems, depending on the time and placement scheme of needle filters, are presented.

Abstract: The development of the palm oil industry is followed by the increased amount of lignocellulosic biomass waste. Lignocellulosic biomass waste contains cellulose and hemicellulose which are potential sources of C6 and C5 sugars. C5 or pentose can be hydrolyzed into furfural through the hydrolysis process and then dehydration reaction using the acid catalyst in various kinds of solvent. At this moment, the highest yield of furfural in the acid-catalyzed hydrolysis of xylose in water resulted in only about 50.0w-%. Other methods such as salt addition or the use of various organic solvents lead to new challenges both in purification and environmental issues. Therefore in this study, 70.0w-% ethanol in water was utilized as the solvent in a range of temperatures (140-170°C) and concentration of sulfuric acid (0.1-0.5M) up to 120 minutes reaction time. As the outcomes, the shorter time was needed to achieve maximum furfural yield with the increase of temperature and acid concentration with the water and the ethanol as the solvent. Improvement was shown in the highest furfural yield achieved up to 70.0-72.0mol-% (after 15 min at 170°C, 0.2-0.5 M concentration of H₂SO₄). The results showed the potential use of ethanol as a green solvent to produce furfural from xylose.

Abstract: Dimethyl ether (DME) is apromising alternative for substituting petroleum fuel including gasoline, liquified petroleum gas, and diesel. In this research, the utilization of red mud as catalyst was investigated to dehydrate methanol to Dimethyl Ether (DME). Red mud is a solid waste from the bauxite industry which lead to environmental issues if did not treat properly. The catalyst characteristics were determined in terms of porosity, crystallinity, elemental composition, and pores size distribution. The catalysts activity was evaluated in a fixed-bed reactor at temperature range 200-300 °C. The influence of different parameters, including temperature and type of catalyst were varied to obtain the optimum reaction condition. The results revealed that the highest methanol conversion was 68% at temperature of 300 °C when using calcined red mud catalyst.

Abstract: A wide range of membranes (hydrophobic and hydrophilic) for the task of triethylene glycol dehydration by thermopervaporation was studied. The transport characteristics of the membranes using individual liquids (water, triethylene glycol) were determined in the thermopervaporation process with varying temperature of the feed flux (40-). The maximum water flux (3.7 kg/m²∙h) in all the studied temperature ranges was demonstrated by the commercial pervaporation hydrophobic PolyAn membrane. For the commercial hydrophilic membrane MDK-I water flux at 80 °С was 2.8 kg/m²∙h. During thermopervaporation of triethylene glycol in the studied temperature range, TEG flux through the membranes was not observed, which shows the advantage of this process for TEG dehydration. For the first time, experiments were provided using PolyAn membranes to removal water from TEG by thermopervaporation with porous condenser. The maximum permeate flux (1.9 kg/m²∙h) was achieved for the PolyAn membrane at a concentration of 70 % wt. TEG in water

Abstract: The foam-mat dryingprocessof egg white, developed in the food industry, promotes a porous product, brittle and easy to grind. The powderedegg white has a good rehydration properties, safer consumption and storage conditions than fresh product, keeping the high level of proteins and vitamins contained in the egg. In this way, the objective of this work is to study, through numerical computational simulation, the physical aspects of the duck egg white foam-matdrying process. For this, the foam was characterized by its density, percentage of expansion, air over run, stability and moisture. Temperature (50, 60 and 70°C), stirring rate (levels 6, 7 and 8) and stirring time (4, 5 and 6 minutes) are taken as input conditions and the product final moisture and drying time are the output variables. Drying was performed based on the complete factorial 23 + 3 central point experimental design in this procedure. It has been observed that the time and stirring rate significantly influence the product final moisture and that the drying temperature is predominant for the total process time. From the foam moisturedata, adjustments of empirical mathematical models were made; evidencing that theModifiedPage and the Page models provided the best results, with a standard deviation lower than 0.01 and the coefficient of determination above 0.99. For this analysis, the case where the drying temperature, time and the stirring rate were, respectively, 70 °C, 6 minutes and 8 level, presented the best results.

Abstract: Polymer electrolyte membranes (PEM) have a potential to become power sources in automotive industry and other household applications. PEM such as sulfonated polyetheretherketone (SPEEK) have acceptable operating temperature range but proton conductivity is dependent on amount of sulfonic groups attached to the polymer backbone (degree of sulfonation). At the same time, the sulfonic groups cause sorption of water from surrounding vapour or liquid. This factor may lead to mechanical failure if membrane absorbs too much water. Modification of PEM by adding ionic liquids (IL) may provide good proton conductivity but presence of water could also be critical factor of membrane stability as in high humidity conditions IL are washed out of membrane and replaced by water molecules. PEM with IL inclusions could be potentially used at temperatures close to water boiling point and higher as IL used in this research are thermally stable in temperatures up to 200°C.