Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) - Volume 16, Issue 1, 2023

Enzymes are highly specific and highly sensitive biocatalyst proteins that play important roles in various life processes. As they are proteins, thus, they are composed of amino acids joined together to form chains. These amino acids are linked by peptide bonds that form between the amino-terminal and carboxylic end. There is the multifaceted application of enzymes in various sectors that include food, textile, paints, pharmaceuticals, leather, oil industries, etc. There is a wide range of sources available for the extraction of enzymes. The commercially important enzymes are generally harvested from microbial sources. Some enzymes are produced extracellularly while some enzymes are produced intracellularly. The production of this bioactive compound could be enhanced by applying suitable optimization techniques, genetic engineering tools, and other modern techniques. One of the major challenges in the commercial production of enzymes is their extraction in pure form without losing their properties. Extraction of enzymes starts from upstream processing that mainly includes two types of fermentation; one is submerged fermentation and another one is solid-state fermentation. After upstream processing, downstream processing is followed which includes cell disruption, filtration, sedimentation and centrifugation, flocculation and coagulation, and chromatography. Then, enzyme purification strategies are followed (salting-out method, dialysis, gel filtration, ion-exchange chromatography, gel electrophoresis. The purpose of down streaming is to purify and concentrate the enzyme from the complex bulk matrix. A significant amount of total production cost is contributed by downstream processing. The review discusses the industrial importance of enzymes and their downstream processing techniques economically and sustainably.

Aim: This study aimed at developing a composite structure heat pipe. Background: Conventionally, the heat pipe enclosure is made out of a single continuous conductive material corresponding to minor heat losses to the surrounding through the middle section, which ideally needs to be adiabatic in nature. The insulating nature of the carbon fiber reduces the axial heat losses and improves the latent heat of vaporization. Objective: The objective of this study is to develop a carbon fiber-reinforced composite heat pipe and a test rig to check the performance of the heat pipe. Methods: The hand lay-up technique is used to develop a composite structure heat pipe with a carbon fiber adiabatic section. A test rig is developed to check the performance of the heat pipe. Moreover, the weight comparison is made for a conventional and composite structure heat pipe. Results: The test results reveal that the composite structure heat pipe gives weight reduction in the range of 25 to 30 percent than the conventional heat pipe for identical dimensions and also shows a faster heat absorption rate. Conclusion: Conventional heat pipe may be replaced with the lightweight composite structure heat pipe.

Aims/Objective: The current study evaluates the effectiveness of a blended tri-solvent system composed of monoethanolamine (MEA), diethanolamine (DEA), and piperazine (PZ) for removing the carbon dioxide (CO2) from the stored gas reservoir. The developed system is intended to be both environmentally benign and productive. Methods: The CO2 absorption was carried out for the total solvent (5, 10, and 15% v/v), during the course of three temperature ranges (20, 25, and 30°C) while maintaining the reservoir pressure of 1.5, 2, and 2.5 bar. The fraction of DEA: MEA has been restricted to 0.2, 0.5, and 0.8, with simultaneous loading of anhydrous PZ ranging from 0 to 2 gm. and agitation speed for step intervals of 300, 600, and 900 rpm. For the purpose of investigating the synergetic effects of the process parameters on the rapid absorption of CO2 (ξ) and the initial CO2 absorption rate (0), Box-Behnken Design (BBD) of response surface methodology (RSM) has been exploited. The design of experiments (DoE) assisted artificial neural network (ANN) and metaheuristic approach of hybridising ANN-whale optimization algorithm (WOA) was also developed and utilised to train and test the developed model. Three optimization models based on RSM, DoE-WOA and ANN-WOA were compared. Under the optimized operating conditions pertaining to DoE, DoE-WOA and DoE-ANN-WOA, (0 = 3.340, 3.460 3.513 gm./min-250 mL) and (ξ = 17.114, 18.069, 18.145 gm./250 mL) were obtained. Results: The hybridised DoE-ANN-WOA shows promising results in correlation with the experimental outcomes having error % for 0 & ξ of 0.790 & 1.31. Conclusion: The DoE-ANN-WOA tends to be selected to predict the optimal absorption conditions as compared to other optimization techniques used in current article.

Objective: The objective of this study is to explore and emphasize the influence mechanism and law of gas parameters on pressure port design. Methods: CFD commercial software FLUENT was used for numerical simulation in this study, and a three-dimensional numerical model was employed to improve the accuracy of calculation. The GWE experimental platform was also built to verify the theoretical and numerical analysis results. Results: When the expansion ratio α is raised from 1.35 to 2.0, the average shock velocity vs can increase by about 4.9%, and when raising the compression ratio from 1.05 to 1.2, the change of vs is only 1.4% relatively. Raising the expansion ratio value from 1.35 to 2.0, the optimal offset of the high- and medium-pressure ports only changes by 5.3%, and the decrease of the ejection rate caused by the deviation of the aforementioned offset is only about 4.3%,which proves that the equipment has strong ability to resist fluctuations of working conditions. Conclusion: Moving velocity of the shock wave varies with temperature, working pressure ratio and adiabatic index of the gas. The increase of high- and low-pressure inlet gas temperatures will cause an increment of vs and as, and the influence of high-pressure inlet gas temperature Tht on vs is greater. There are optimal high- and medium-pressure port offsets under different pressure ratios as the experimental results have shown. When the pressure ratio remains constant, the change in pressure value does not have a significant impact on the optimal port design and equipment performance.

Aims: In order to explore the adsorption effect of tea on heavy metal ions in industrial wastewater, Ag⁺ is used as the research object in this paper. Background: In recent years, heavy metal pollution in water has seriously affected human health and the stability of the ecological environment. In order to reduce the harmfulness of heavy metals, various countries have issued a variety of control standards for heavy metals in water, but there are still great restrictions in the prevention and control technology and level of heavy metal pollution. Therefore, how to effectively treat heavy metal pollution in water has become a hot topic in the field of water pollution management. Objective: The optimized conditions of the adsorption are obtained. Properties of the thermodynamics, adsorption kinetics, and adsorption isotherm are obtained. Methods: In order to determine the best adsorption conditions for Ag⁺, the influence of factors such as pH value, initial concentration of Ag⁺, tea dosage, contact time, and adsorption temperature on the adsorption effect of tea is studied. The thermodynamics, adsorption kinetics, and adsorption isotherm are studied. Results: The results showed that when the temperature is 25°C, the pH of the solution was 3.5, the amount of adsorbent was 2.5 g/L, the initial concentration of Ag⁺ was 125 μg/L and the contact time was 30min, the adsorption rate was highest, reaching 98.11%. The thermodynamic study of adsorption showed that at room temperature and above (298.15-318.15 K), ΔG° < 0, indicating that the adsorption process can be spontaneous. The value of ΔG° in this study is between -20 and -80 kJ/mol, indicating that this is a physicochemical adsorption process. ΔH° = -80.111 kJ/mol < 0, indicating that the adsorption process of Ag⁺ is exothermic. ΔS° = -188.977 J/(mol·K) < 0, indicating that the adsorption is a process of entropy reduction. The adsorption kinetics study showed that the adsorption equilibrium capacity of different concentrations had a large gap with the experimental results, and the correlation coefficient was small by fitting the quasi-first-order kinetic equation and combining it with the experimental measurements. When the quasi-second-order kinetic equation was used, the calculated values of the equilibrium adsorption capacity of each concentration were basically close to the experimentally measured values, and the correlation coefficient was large, so the kinetics of the adsorption system of Ag⁺ by tea conformed to the quasi-second-order kinetic equation. The adsorption isotherm of this adsorption process is accorded with the Freundlich model and belonged to heterogeneous adsorption. Conclusion: Tea is a good adsorbent and has the potential for adsorption of Ag⁺.