Achieve Process Intensification Research Articles

Intensification of organic reactions with hybrid flow reactors

The intensification of chemical processes, which means improving their efficiency and cutting down energy consumption, requires more automation and non-conventional energy sources, as well as new, efficient and scalable protocols which need to be implemented in continuous flow reactors. We showed that flowing systems are advantageous when using conductive heating or non-conventional energy sources such as microwave (MW) and ultrasound (US) irradiation. We developed several hybrid flow reactors suitable for organic reactions with the aim of optimizing heat and mass transfer and achieving process intensification. Here we present a series of applications of a simple flow reactor that uses an HPLC pump, a column heater and suitable columns filled with a supported catalyst. Using the same column packed with a commercially available derivatized acidic silica we efficiently performed two reaction types: the nucleophilic opening of epoxides with a series of alcohols and the Friedländer quinoline synthesis. In both cases we obtained pure products in excellent yield in a few minutes. The set of experiments on the epoxide opening could be repeated on a hybrid flow reactor under sequential MW/US irradiation, though at lower temperature. A suitable combination of 1D and 2D NMR experiments (i.e. 1H– 13C HMQC, 1H– 1H COSY and 1H– 1H NOESY) was applied to unambiguously assign the stereochemistry of hydroxyethers from the nuclephilic cleavage of limonene oxide.

Mixing intensification for the mineral industry

AbstractThe modern mineral industry uses hydrometallurgical processes to extract metals from ores. Typically, a large volume of ore slurry is treated in mixing tanks in a mineral processing plant, for leaching, digestion, precipitation, and other chemical processing to obtain pure metals or concentrated ores. This paper discusses mixing intensification as a means to achieve process intensification for the mineral process industry. Areas where mixing intensification can be applied are illustrated with case examples. Among them, it was suggested that for slowly reacting slurry systems typical in the mineral processing operations, high solid loadings should be considered to boost throughput. Improved agitator energy efficiency can be achieved by removing baffles, at very high solid loadings. Slurry stratification in tanks can be used to boost either solids residence time or slurry through flow.

Intensification of esterification of acids for synthesis of biodiesel using acoustic and hydrodynamic cavitation

Cavitation results in conditions of turbulence and liquid circulation in the reactor which can aid in eliminating mass transfer resistances. The present work illustrates the use of cavitation for intensification of biodiesel synthesis (esterification) reaction, which is mass transfer limited reaction considering the immiscible nature of the reactants, i.e., fatty acids and alcohol. Esterification of fatty acid (FA) odour cut (C 8–C 10) with methanol in the presence of concentrated H 2SO 4 as a catalyst has been studied in hydrodynamic cavitation reactor as well as in the sonochemical reactor. The different reaction operating parameters such as molar ratio of acid to alcohol, catalyst quantity have been optimized under acoustic as well as hydrodynamic cavitating conditions in addition to the optimization of the geometry of the orifice plate in the case of hydrodynamic cavitation reactors. Few experiments have also been carried out with other acid (lower and higher)/methanol combination viz. caprylic acid and capric acids with methanol with an aim of investigating the efficacy of cavitation for giving the desired yields and also to quantify the degree of process intensification that can be achieved using the same. It has been observed that ambient operating conditions of temperature and pressure and reaction times of <3 h, for all the different combinations of acid (lower and higher)/methanol studied in the present work, was sufficient for giving >90% conversion (mol%). This clearly establishes the efficacy of cavitation as an excellent way to achieve process intensification of the biodiesel synthesis process.

Intensification of Mixing

An overview of the intensification of industrial mixing will be presented. In many instances, it is not sufficient to increase a chemical reaction rate to achieve process intensification, as the rate of a reaction could be limited by mixing, heat transfer and mass transfer. An important strategy for process intensification is to increase mixing rate, heat transfer rate and mass transfer rate. A range of methods are reviewed, for both conventional stirred reactors and alternative forms of reactors, all with the aims of achieving process intensification through enhanced mixing, heat and mass transfer.

Influence of inclined plates on the expansion behaviour of particulate suspensions in a liquid fluidised bed

The installation of inclined plates into fluidised beds yields significant increases in segregation rates, and hence new opportunities for achieving process intensification. The expansion behaviour of suspensions in such a system was investigated both experimentally and theoretically. The present paper builds upon the work of Galvin and Nguyentranlam (2002), incorporating improvements into the general theoretical framework, and extending the description of the system to cover binary suspensions. The paper provides a definitive assessment of the model, using an idealised experimental system that matches the arrangement used to define the model. The validation of the model is far more thorough than in the previous study, covering both the suspension concentrations, and the suspension lengths within the inclined channel. The theoretical description is likely to prove useful when applying the new system to adsorption, crystallization, and particle separations. In general, there is good agreement between the theoretical model and the experimental data, thus indicating the essential elements of this new fluidised bed system have been captured.