Band 20, Heft 8

In order to accomplish efficient mixing of liquids with large differences in flow rates, an efficient multi-orifice impinging transverse (MOIT) jet mixer is used in this paper. Its structure combines a conventional MOIT jet mixer with a venturi jet mixer to improve the mixing efficiency of the MOIT jet mixer. The flow characteristics and mixing effects inside the conventional and efficient jet mixer are numerically simulated by means of a Multiphase Models. Based on building the experimental platform, the maximum error between the simulation results and the experimental results obtained with the high-speed camera is 8.42%, which verifies that the model and simulation method applies to the simulation of the mixer. In addition, the paper uses MATLAB software to obtain the interphase contact area at the transverse orifice section and verifies that the contact area at the transverse orifice section affects the mixing effect of the mixer. The droplet size distribution was also analyzed by the CFD-PBM model. The results show that the efficient MOIT jet mixer has better mixing efficiency and mixing effect, and the optimal values of the number of orifices and main fluid flow rate of the jet mixer exist. In addition, the mixing effect of the mixer showed a decreasing trend with the increase of the orifice size. The results of this paper complete the optimization of the parameters of the MOIT jet mixer, facilitating its industrial application. And combining two different mixers to create a novel jet mixer, which provides a direction for the development of new jet mixers and helps to promote the development of the fine chemical industry.

The article presents the results of studies of the process of obtaining NPK fertilizer from low-grade phosphate raw materials with P 2 O 5 of about 18%. Phosphate raw materials were leached with a mixture of nitric-phosphoric acids with the addition of potassium carbonate, which serves as a source of potassium in the final product. The main parameters determined were the content of the main nutrients P 2 O 5 :N:K 2 O, temperature and time of the leaching process. According to the graphical method, the “apparent” activation energy of the heterogeneous process is found, which is equal to 3.8 kJ/mol indicates the intradiffusion nature of the process. Methods of chemical analysis, scanning electron microscopy and XRD analysis were used for a comprehensive study of raw materials and final products.

A mathematical model is developed and designed for the cumene reactor in cumene production process in Hindustan Organic Chemicals Limited (HOCL), Kochi with improved operating conditions. High purity cumene is produced by the alkylation of benzene with propylene in this catalytic condensation process where solid phosphoric acid (SPA) is used as the catalyst. The mathematical model has been derived from mass and energy balance equations considering the reactor as fixed packed bed reactor and two different numerical methods are presented here to solve the modelling equations. The explicit finite difference method (FDM) involves the approximation of derivatives into finite differences, and in the other one, orthogonal collocation (OC), Ordinary Diffeential Equations (ODEs) are formed at the collocation points and are solved using Runge–Kutta fourth order numerical scheme. Here the analysis shows that the predictions from the model are in good alignment with the plant data. The combined feed has the optimum value of 1:2:8 for propylene, propane and benzene and the profiles of temperature and concentration can be obtained along the reactor. The model has been implemented in COMSOL Multiphysics as a packed bed reactor using the same parameters collected from the plant of study. It has been found that the reaction occurs at a satisfactory level even with a low temperature than the reactor temperature at the plant by changing the catalytic particle size. The reaction performance is also analysed for the physical properties like porosity and catalyst size.

To study the affinity of 3A aluminosilicate adsorbents to prevent oligomerization of olefin molecules and forming green oil, physical and chemical properties of 3A molecular sieves are measured by using characterization techniques such as temperature-programmed desorption (TPD), nitrogen (N 2 ) and water adsorptions, X-ray diffraction (XRD), X-ray fluorescence (XRF), crushing strength, and carbon dioxide (CO 2 ) adsorption. Moreover, coke formation affinities of the understudy adsorbents are evaluated in a bench-scale system using 1-butene and 1,3-butadiene at temperatures of 220 and 260 °C, and outcomes are validated against the actual data gathered from an industrial scale olefin dehydration plant. Results confirm that the type of binder and the amount of ion exchange affect the performance of a 3A molecular sieve nominated for dehydrating olefinic streams. The binder with the least amount of acidity is preferred, and at least 35% of Na ions of the 4A zeolite should be exchanged with K ions to make it applicable for synthesizing an appropriate 3A molecular sieve. Furthermore, to control the oligomerization and inhibit green oil formation, the CO 2 adsorption and acidity of Trisiv shape molecular sieves with the sizes of 1/4 inch should be less than 0.5 wt % and 1.7 mmol NH 3 /g, respectively. For extrudate shape with the sizes of 1/16 inch CO 2 adsorption and acidity should be less than 0.2 wt % and 2.2 mmol NH 3 /g, respectively .

The effect of operating parameters such as reaction mixture inlet pressure p 1 (101.3–1013.2 kPa), methanol to oil molar ratio M 1 (3–12), the concentration of catalyst C c (0.0–1.0 wt%), temperature T (25–50 °C) and the number of passes of the reaction mixture through the venturi type hydrodynamic cavitation reactor n (1–12) on alkali-catalyzed transesterification of sunflower oil with methanol assisted by hydrodynamic cavitation (ACTC) on the value of the degree of triglyceride conversion (DTC) was investigated. ACTC was performed by the venturi-type hydrodynamic cavitation reactor (VCR) of our construction. It was found that the values of DTC increase with the increase in p 1 , M 1 , C c , and n , and decrease with the increase in T . Cavitation yield (CY) values were calculated. The ACTC was proved to be the simplest, fastest, and most highly energy-efficient current technology for the production of biodiesel.

The fat-liquoring is an important step in leather making before dying to improve the glossiness, appearance, physical and chemical qualities of the leather. Synthetic sulphonated or sulphited oils are generally used to fill fibrous leather & to give it soft, elastic and loose characteristics. Natural fat-liquors (vegetable and animal-based) and synthetic fat-liquors are the two types of emulsions. The emulsion’s charge can be anionic, cationic, or nonionic. In this study, fat-liquor has been made from a bio-waste, namely tallow, which is obtained from a slaughterhouse as a byproduct of the animal hides and skin processing for leather. Triglycerides, a combination of oleic, stearic, and palmitic fatty acids, and glycerol make up the majority of this animal fat. Fat-liquor is made through a series of three reactions, namely, amidation, esterification, and sulphitation. Amidation helps to increase the hydroxyl groups. To react with fat, alkanol amine with a wide emulsifying characteristic isutilised. Anhydrides derived from di-carboxylic acids were then esterified with amidated fat in the next phase. By altering the process recipe, the stability of the emulsion product has been examined, and required raw materials are optimized. Finally, aqueous hydrolyzed sodium metabisulphite is used to sulphite the product, yielding bisulphite and hydroxide ions. The saponification and acid values are computed. The end product has a distinct advantage (anti-foaming & fire-retardant) over traditional fat-liquoring techniques. Material balance is performed once the process flow sheet was created. The process has been scaled up with the help of a preliminary reactor design. The degree of fat-liquoring and the process’ performance are revealed by FTIR spectrum. NMR was used to determine the final product’s structure.

Developing high-performance electrocatalysts using simple and controllable methods is of interest to reduce the cost of polymer electrolyte membrane fuel cells. In this study, platinum is alloyed with nickel and supported on carbon (Pt–Ni/C) via an ultrasound-assisted route. The crystallite and particle sizes of the obtained nanoparticles were smaller than the commercial carbon-supported Pt nanoparticles. The sonochemically synthesized Pt–Ni/C nanoparticles exhibited superior electrocatalytic properties than the commercial Pt/C nanoparticles in the fuel cell operation. Electrochemical measurements performed with Pt–Ni/C electrocatalyst displayed excellent oxygen reduction and higher electrochemical active surface area (EASA). Optimum fuel cell performance based on peak power density using Pt–Ni/C electrocatalyst was observed as 0.28 W/cm 2 at 0.39 V.

The industrial wastewater treatment is carried out in an external loop airlift reactor (EL-ALR) and sectionalized EL-ALR. The airflow rate is optimized in EL-ALR and sectionalized EL-ALR for better degradation of wastewater. The 74% degradation is obtained in sectionalized EL-ALR as compared to EL-ALR for continuous aeration up to 32 h. For higher superficial gas velocity ( U G ) percentage degradation is decreased due to shear stress on microorganisms. The extent of degradation is obtained 77 and 80% for the effect of hydrogen peroxide (H 2 O 2 ) and combination of H 2 O 2 and Fenton reagent in an EL-ALR. The computational fluid dynamic (CFD) simulation validated with experimental results of gas hold-up and liquid circulation velocity compared in EL-ALR sectionalized EL-ALR over a broad range of superficial gas velocity 0.0024 ≤  U G  ≤ 0.016 m/s. The comparison of CFD and experimental values of gas hold-up and liquid circulation velocity are in good agreement.