The optimization of spray-drying process for the development of apricot powder using response surface methodology

PurposeApricots are not only nutritionally-rich but also possess pharmacological significance owing to their high antioxidant activity, and they are rich in vitamins, fibers, bioactive phytochemicals and minerals. Because of its immense organoleptic characteristics, apricot juice (AJ) is well accepted; however, it has a limited shelf-life, thereby demanding it to be converted into other shelf-stable form. One of the approaches is converting this juice into dehydrated powder. Amongst the various dehydration techniques available, spray drying is usually preferred; however, it involves the use of several independent variables, which need to be optimized, thus prompting to optimize the process to obtain spray dried apricot powder (SDAP) with improved quality.Design/methodology/approachThe spray-drying process of apricot juice was done using the response surface approach. The process variables included the inlet air temperature of 135–220°C, gum arabic concentration of 4–25%, feed flow rate of 124–730 mL/h, feed total soluble solids (TSS) of 10-30°Brix and atomization speed of 11,400–28,000 rpm. The dependent responses were powder yield, hygroscopicity, solubility, moisture content, carotenoids (CT), ascorbic acid (AA), radical scavenging activity (RSA), lightness, wettability, bulk density, particle density and porosity.FindingsAmongst all independent variables, inlet air temperature had most predominant impact on all the investigated responses. The optimum processing conditions for development of apricot powder with optimum quality were 190°C inlet air temperature, 18.99% gum arabic, 300.05 mL/h feed flow rate, 24°Brix feed TSS and 17433.41 rpm atomization speed. The experimental values were found to be in agreement with the predicted values, indicating the suitability of models in predicting optimizing responses of apricot powder. Flowability as Carr's index (CI) (22.36 ± 1.01%) suggests fair flow of powder. Glass transition temperature of powder was 57.85 ± 2.03°C, which is much higher than that of ambient, suggesting its better shelf stability.Originality/valueTo the best of author's knowledge, very limited or very few studies have been carried out on the spray-drying process for the manufacture of SDAP. The results of this investigation will open up new horizons in the field of food industry in the Union Territory of Jammu and Kashmir, India or elsewhere in the apricot-growing areas of India.

Statistical Modeling and Performance Optimization of a Two-Chamber Microbial Fuel Cell by Response Surface Methodology

Microbial fuel cell, as a promising technology for simultaneous power production and waste treatment, has received a great deal of attention in recent years; however, generation of a relatively low power density is the main limitation towards its commercial application. This study contributes toward the optimization, in terms of maximization, of the power density of a microbial fuel cell by employing response surface methodology, coupled with central composite design. For this optimization study, the interactive effect of three independent parameters, namely (i) acetate concentration in the influent of anodic chamber; (ii) fuel feed flow rate in anodic chamber; and (iii) oxygen concentration in the influent of cathodic chamber, have been analyzed for a two-chamber microbial fuel cell, and the optimum conditions have been identified. The optimum value of power density was observed at an acetate concentration, a fuel feed flow rate, and an oxygen concentration value of 2.60 mol m−3, 0.0 m3, and 1.00 mol m−3, respectively. The results show the achievement of a power density of 3.425 W m−2, which is significant considering the available literature. Additionally, a statistical model has also been developed that correlates the three independent factors to the power density. For this model, R2, adjusted R2, and predicted R2 were 0.839, 0.807, and 0.703, respectively. The fact that there is only a 3.8% error in the actual and adjusted R2 demonstrates that the proposed model is statistically significant.

Machine Learning Models Applied to Manage the Operation of a Simple SWRO Desalination Plant and Its Application in Marine Vessels

In this work, two machine learning techniques, specifically decision trees (DTs) and support vector machines (SVMs), were applied to optimize the performance of a seawater reverse osmosis (SWRO) desalination plant with a capacity of 100 m3 per day. The input variables to the system were seawater pH, seawater conductivity, and three requirements: permeate flow rate, permeate conductivity, and total energy consumed by the desalination plant. These requirements were decided based on a cost function that prioritizes the water needs in a vessel and the maximum possible energy savings. The intelligent system modifies the actuators of the plant: feed flow rate control and high-pressure pump (HPP) operating pressure. This tool is proposed for the optimal use of desalination plants in marine vessels. Although both machine learning techniques output satisfactory results, it was concluded that the DTs technique (HPP pressure: root mean square error (RMSE) = 0.0104; feed flow rate: RMSE = 0.0196) is more accurate than SVMs (HPP pressure: RMSE = 0.0918; feed flow rate: RMSE = 0.0198) based on the metrics used. The final objective of the paper is to extrapolate the implementation of this smart system to other shipboard desalination plants and optimize their performance.

A Theoretical Analysis on a Multi-Bed Pervaporation Membrane Reactor during Levulinic Acid Esterification Using the Computational Fluid Dynamic Method

Pervaporation is a peculiar membrane separation process, which is considered for integration with a variety of reactions in promising new applications. Pervaporation membrane reactors have some specific uses in sustainable chemistry, such as the esterification processes. This theoretical study based on the computational fluid dynamics method aims to evaluate the performance of a multi-bed pervaporation membrane reactor (including poly (vinyl alcohol) membrane) to produce ethyl levulinate as a significant fuel additive, coming from the esterification of levulinic acid. For comparison, an equivalent multi-bed traditional reactor is also studied at the same operating conditions of the aforementioned pervaporation membrane reactor. A computational fluid dynamics model was developed and validated by experimental literature data. The effects of reaction temperature, catalyst loading, feed molar ratio, and feed flow rate on the reactor’s performance in terms of levulinic acid conversion and water removal were hence studied. The simulations indicated that the multi-bed pervaporation membrane reactor results to be the best solution over the multi-bed traditional reactor, presenting the best simulation results at 343 K, 2 bar, catalyst loading 8.6 g, feed flow rate 7 mm3/s, and feed molar ratio 3 with levulinic acid conversion equal to 95.3% and 91.1% water removal.

Adsorption of organic matter from papermaking wastewater by CoFe2O4-coated sand in batch and fixed-bed systems

The secondary treated effluents of pulp and paper mills contain high chemical oxygen demand (COD) that is associated with organic matter. Therefore, this study explores the adsorption of substances contributing to COD using CoFe2O4 and quartz sand-coated CoFe2O4 in batch and fixed-bed column experiments. X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller analysis, and X-ray photoelectron spectroscopy were used to characterize the adsorbents. The quartz sand-loaded CoFe2O4 exhibited a larger pore volume and average pore size. Batch experiments revealed that adsorption on CoFe2O4 closely fit the pseudo-second-order model. To explore the effects of bed depth, feed flow rate, and initial solution pH on the breakthrough characteristics of CoFe2O4-coated sand, fixed-bed column experiments were conducted, and the breakthrough curves were drawn from the ratio of influent COD concentration to effluent COD concentration. The breakthrough time decreased with an increase in the feed flow rate and initial pH but increased with the bed depth. According to the X-ray photoelectron spectroscopy analysis, CoFe2O4-coated sand showed excellent stability due to negligible leaching of metallic elements. These findings have important implications for the advanced treatment of industrial wastewater.

Distillation optimization: Parameterized relationship between feed flow rate of a steady-state distillation column and heat duties of reboiler and condenser

The paper considers the problem of maximum efficiency for the system of distillation columns. Columns in such systems are connected in parallel or sequential way. The mixture being separated is assumed to be close to ideal one. Authors parameterize the relationship between feed flow rate and heat duties of a steady-state binary distillation column using two parameters: the reversible efficiency and the irreversibility coefficient. This relationship is later being used to solve the problems about optimal distribution of heat and feed flows within the system. The results obtained allow to estimate minimum heat energy demand for distillation of the given feed flow, maximum performance and efficiency of the system.

Dynamic & CFD modeling of a continuous-flow mixer using fluids with yield stress

A continuous-flow mixer was designed and built in the Mixing Technology Lab, Chemical Engineering Department at Ryerson University to study mixing of xanthan gum solutions in water, a pseudoplastic fluid possessing yield stress. The extent of flow non-ideality was quantified using a dynamic model that incorporated the extent of channeling and the effective mixed volume within the mixing vessel. Dynamic tests were made using a frequency-modulated random binary input of a brine solution. The same experiments were simulated using Fluent, a Computational Fluid Dynamics (CFD) package. CFD flow fields were used to obtain the system dynamic response to a tracer injection applied at conditions indentical to the experimental conditions. The extent of channeling and effective mixed volume were determined and then compared with the parameters obtained experimentally. Experimental and CFD results show that the extent of non-ideal flow is significantly affected by impeller speed, impeller type, feed flow rate, fluid rheology, and exit location. The performance of continuous mixed vessels can be improved by increasing impeller speed, decreasing feed flow rate, and decreasing solution concentration. However, decreasing feed flow rate and solution concentration reduces the production capacity of the process. Increasing impeller speed may require modification to the motor and can cause air entrainment. Therefore, other remedies such as relocating the exit location and using the proper type of impeller may be taken into consideration. The results show that the extent of non-ideal flow was reduced using the bottom output and flow efficiency in the vessel was enhanced using A320 impeller.

Dynamic & CFD modeling of a continuous-flow mixer using fluids with yield stress

A continuous-flow mixer was designed and built in the Mixing Technology Lab, Chemical Engineering Department at Ryerson University to study mixing of xanthan gum solutions in water, a pseudoplastic fluid possessing yield stress. The extent of flow non-ideality was quantified using a dynamic model that incorporated the extent of channeling and the effective mixed volume within the mixing vessel. Dynamic tests were made using a frequency-modulated random binary input of a brine solution. The same experiments were simulated using Fluent, a Computational Fluid Dynamics (CFD) package. CFD flow fields were used to obtain the system dynamic response to a tracer injection applied at conditions indentical to the experimental conditions. The extent of channeling and effective mixed volume were determined and then compared with the parameters obtained experimentally. Experimental and CFD results show that the extent of non-ideal flow is significantly affected by impeller speed, impeller type, feed flow rate, fluid rheology, and exit location. The performance of continuous mixed vessels can be improved by increasing impeller speed, decreasing feed flow rate, and decreasing solution concentration. However, decreasing feed flow rate and solution concentration reduces the production capacity of the process. Increasing impeller speed may require modification to the motor and can cause air entrainment. Therefore, other remedies such as relocating the exit location and using the proper type of impeller may be taken into consideration. The results show that the extent of non-ideal flow was reduced using the bottom output and flow efficiency in the vessel was enhanced using A320 impeller.

Influences of Technological Parameters on Cross-Flow Nanofiltration of Cranberry Juice

The paper focused on the influence of operative conditions on the separation of benzoic acid from 10 °Brix cranberry juice by cross-flow nanofiltration with a plate and frame pilot scale (DDS Lab Module Type 20 system). Six kinds of commercial nanofiltration membrane were investigated. The results showed that the rejection of benzoic acid was significantly lower than that of other components in cranberry juice, including sugars and other organic acids. In a range of 2–7.5 L/min, feed flow rate slightly affected the performance of nanofiltration. Higher temperatures resulted in higher permeate flux and lower rejection of benzoic acid, whereas rejection of sugar and organic acid was stable at a high value. In a range of 2.5–5.5, pH also significantly affected the separation of benzoic acid and negative rejection against benzoic acid was observed at pH 4.5 with some of the membranes. This implies that pH 4.5 is considered as an optimum pH for benzoic acid separation from cranberry juice. The lower permeate flux caused a lower rejection of benzoic acid and negative rejection of benzoic acid was observed at the low permeate flux. Pretreatment by ultrafiltration with CR61PP membranes could improve the permeate flux but insignificantly influenced the efficiency of separation. The results also indicated that NF99 and DK membranes can be effectively used to separate benzoic acid from cranberry juice.