Conventional Evaporation Process Research Articles

Potash recovery from synthetic potassium rich wastewater and biomethanated distillery effluent using tartaric acid as a recyclable precipitant

Potassium is one to the essential elements for plant and animal life due to its vital nutritional roles. Globally, more than 95% of the potassium chemicals is utilized as fertilizer. Due to shortage of land and vulnerability to climatic conditions, potash production through conventional evaporation process seems difficult in long run. Hence, its recovery from the potassium rich industrial effluents such as biomethanated spent wash (BMSW), can be an attractive option. In the present study, tartaric acid (a recyclable precipitant) was used for potash recovery from potassium rich synthetic wastewater (PWW) and BMSW (potassium concentration = 19.5 g/L and 14.8 g/L, respectively). At an optimum solution pH of 3.5, more than 70% of the total potassium was precipitated out as potassium bitartrate (KHT) from PWW with the stoichiometric tartaric acid dose (1M). Subsequently, the tartaric acid was regenerated by converting KHT into potassium nitrate (KNO 3 ). Around 77% potassium could be converted into KNO 3 using Mg(OH) 2 and HNO 3 with 80% regeneration of tartaric acid. Under similar conditions, ∼ 70% potassium precipitation with 62% color removal could be achieved from the BMSW stream. Based on the results, it can be suggested that the selective extraction using tartaric acid has high potential for potash recovery from waste streams. A detailed study should focus on the optimization of conditions for recovery of potassium from real effluent and its purity in the residue should be verified. In addition, suitable conditions for regeneration of tartaric acid should also be obtained. • Potash recovery was done from synthetic and real BMSW wastewaters by tartaric acid. • K-recovery ( ∼ 70%) as potassium bitartrate was achieved from both wastewaters. • Potash (purity = 74%) along with tartaric acid recovery (> 80%) was obtained. • ∼ 50% TOC and 62% color removals could also be achieved from acidified BMSW.

Rheological behavior of sour cherry juices concentrated by ohmic and conventional evaporation processes under vacuum

In this study, sour cherry juice was evaporated up to 65% total soluble solid content (TSSC) under vacuum (25 kPa) by ohmic-assisted vacuum evaporation (OAVE) and vacuum evaporation (VE). The effects of voltage gradients (10–14 V/cm) on the rheological behavior of sour cherry concentrates having different TSCC (30%–65%) were determined, and compared with those of VE. In general, the shear stress increased as the shear rate increased for all concentrations. Since the statistical error values of Power Law and Newton models were similar (p > .05), the most appropriate model describing the rheological behavior was chosen as Newton model being more nominative and mathematically simpler. The viscosity of concentrates (30%–65%) varied in the range of 0.003–0.119 Pa.s. The increase in the viscosity values depending on TSSC during evaporation was similar for both processes. Thus, OAVE could be beneficial alternative method to VE for the purpose of producing fruit juice concentrates having similar rheological properties. Practical applications It is an alternative evaporation method in the literature in recent years by integrating ohmic heating into the evaporation process. However, in order for the ohmic evaporation process to be an alternative, it is necessary to provide qualities of fruit juices similar to or better than the vacuum evaporation process. One of the most important features for the transportation of fruit juices in industrial transport lines is rheological properties. In this study, it is important to determine that the consistency of the product resulting from the use of ohmic heating support in evaporation does not differ from the conventional method. The data obtained in this publication will constitute an important data infrastructure for scaling OAVE operation to industrial systems as an alternative.

Performance of a liquid desiccant-assisted solar juice concentration system for barberry juice

A closed-loop solar juice concentration system equipped with a liquid desiccant bed was investigated for barberry juice concentration and compared with the conventional evaporation processes. An unglazed flat plate solar collector was used for simultaneous regeneration of the desiccant solution. Experimental evaluation of the designed system was carried out at different flow rates of moving air as the circulating gas. The results showed that concentration time decreased from 480 to 360 min when the flow rate increased from 0.006 to 0.014 kg/s. Furthermore, raising the flow rate caused a decrease of 40% in effectiveness of dehumidification and an improvement of 33% in moisture evaporation rate. A minimum specific energy consumption of 3.33 MJ/kg was achieved at the air flow rate of 0.006 kg/s. The results indicated that all concentration methods significantly (p < 0.05) changed the color indices (L*, a*, b*, hue angle, chroma and total color difference) of barberry juice. Although color quality of the concentrated juice by the rotary evaporator was better than the other methods, the solar juice concentration system at the lowest flow rate can be proposed for fruit juice processing industries with regard to energy consumption and acceptable and competitive color quality of the processed juices.

Design and economic analysis of membrane-assisted crystallization processes

Abstract Reverse-osmosis (RO) and porous hydrophobic membranes have attracted attention as an alternative to conventional evaporation for crystallization processes, the latter being recommended especially if low-grade waste heat is available to provide the enthalpy of vaporization. In this work, these two types of membrane-assisted processes are designed and costs are compared with those of conventional single or multiple-effect vacuum evaporation processes. When waste heat is not available, RO processes are shown to be the least expensive because the pumping costs, while significant, are more than offset by the fact that it is not necessary to provide the enthalpy of vaporization of the solvent. When waste heat is available, a conventional evaporation process is favorable because it can also be powered by the waste heat and does not require the capital cost for the membranes.

Wafer-Scale Aluminum Nanoplasmonic Resonators with Optimized Metal Deposition

Spectroscopic ellipsometry is demonstrated to be an effective technique for assessing the quality of plasmonic resonances within aluminum nanostructures deposited with multiple techniques. The resonance quality of nanoplasmonic aluminum arrays is shown to be strongly dependent on the method of aluminum deposition. Three-layer metal–dielectric–metal nanopillar arrays were fabricated in a complementary metal-oxide semiconductor facility, with the arrays of nanopillars separated from a continuous metal underlayer by a thin dielectric spacer, to provide optimum field enhancement. Nanostructures patterned in optimized aluminum, which had been deposited with a high-temperature sputtering process followed by chemical mechanical planarization, display different resonance and depolarization behavior than nanostructures deposited by the more conventional evaporation process. Full plasmonic band diagrams are mapped over a wide range of incidence angles and wavelengths using spectroscopic ellipsometry and compared be...

Tailored Pd–Au layer produced by conventional evaporation process for hydrogen sensing

Here we propose two methods using conventional evaporation process to produce tailored Pd/Au composite thin films for hydrogen sensing. In the first method Pd and Au are evaporated simultaneously using different evaporation rate. In the other, alternated nano-layer of Pd and Au are evaporated. Some characteristics of the thin films and their response to hydrogen when they are deposited over optical fibers are experimentally analyzed. Optical fiber sensors for detection of hydrogen concentration lower than 4% and response time of 10 s approximately are demonstrated. The possibility to precisely control the proportion of the constituents of Pd-alloys thin films to produce optical fiber hydrogen sensors with fast response makes these methods very attractive.

Evaporation Materials for Optical Applications: Reasons for the success of Ternary Oxides

Ternary oxides - often called “mixtures” within the thin film community - have proven their advantages in conventional evaporation processes within the last decade. Today they are established medium and high index materials in the latest designs for optical devices. Applications include products like digital data projectors and CD/DVD-drives. Three successful ternary oxides are described in this article.

Theoretical Aspects on Spatial Thickness Variations in Laser-Deposited Thin Films.

AbstractWe have studied predicted thickness uniformity of thin films deposited by the pulsed laser ablation technique. Unlike a conventional evaporation process, the spatial thickness characteristics of laser-deposited films is controlled by a number of laser and other deposition variables including laser wavelength, pulse energy density, substrate-target distance, area and shape of the laser irradiated spot, etc. The effect of these parameters on the spatial thickness variations have been analyzed by using a model proposed by Singh et. al. [1]. This model is based on the anisotropic expansion of the laser-generated high-temperature and high-pressure plasma, which is initially confined to small dimensions and then expands anisotropically in vacuum. The results show that spatial film uniformity can be improved by decreasing plasma temperature and specific heat capacity ratio of the plasma gas. For large laser irradiated spot diameters (&gt; 8 mm), the film uniformity was found to decrease with decreasing spot diameters, but this trend reversed at smaller: irradiated spot sizes. Depending on the laser irradiated conditions and substrate-target geometry, the thickness variations have been found to vary from (cos θ)2.5 to (cos θ)12. Optimization of various parameters to decrease the spatial-thickness inhomogeneities across the film are also discussed.

Concentration and purification of gelatin liquor by ultrafiltration

Weak gelatin liquor has been concentrated to 15% and above from initial concentration of 5% dissolved solids by the application of ultrafiltration techniques. Applied pressures in the range of 220–350 kPa have been found to be optimum for the concentration as well as purification. An economic evaluation based on the experimental results shows that ultrafiltration is cheaper than that of conventional evaporation processes for the initial concentration and de-ashing of the gelatin liquor.

Freeze concentration of fruit juices.

Concentration of aqueous foods such as fruit juices, milk, beer, wine, coffee, and tea, is a major unit operation in the food industry. Technically feasible processes that are commercially available for the concentration of liquid foods include evaporation, freeze concentration, reverse osmosis, and ultrafiltration. Evaporation is considered to be the most economical and most widely used method of concentration. However, it is not suited for food products with very delicate flavors. Commercial processes for the concentration of such products by membrane separation techniques are not yet available. As compared to the conventional evaporation processes, concentration by freezing is potentially a superior and economic process for aroma-rich liquid foods. In the past, the process, however, was seldom used because of the investment cost and the considerable loss of concentrate in the withdrawn ice, and hence, the quality. Recent technological developments have minimized these two drawbacks associated with the earlier freeze concentration processes. In the coming decade, freeze concentration is seen as a potentially attractive method for the concentration of aroma-rich liquid foods, including fruit juices, coffee, tea, and selected alcoholic beverages. In this article, several aspects of the theoretical considerations behind freeze concentration of fruit juices, the development of new and cheaper designs, and commercially available freeze concentration processes are reviewed. The economics of the process and its application to several other areas of the food industry are also discussed.

The Future of Sputtering in the Electron Microscope Laboratory

In such fields as electronics and optics, the sputtering process is rapidly displacing the conventional evaporation process. Its major advantage is the ability to deposit a variety of refractory metals and dielectric materials with good control and reproducibility. This advantage and numerous others are valid reasons why sputtering may eventually displace thermal evaporation in the typical electron microscope laboratory. Sputtering is readily adapted to the procedures utilized in TEM, however, the following discussion highlights the advantages of sputtering for applying coatings to specimens for SEM.Sputtering is not a new concept. Numerous papers and books had been published before 1900 concerning the use of sputtering for depositing thin films.