Methane is an important raw material for fuel and commodity chemicals production. Energyintensive steam methane catalytic reforming in gas-fired furnaces is the main industrial process for methane conversion to synthesis gas and further to other chemicals. Methane conversion by means of non-thermal plasma technologies has attracted attention in the last years, as no pre-heating of the feedstream at high temperatures is needed. Electric energy is consumed in producing energetic electrons for molecule bonds breaking, instead of gas heating, thereby overcoming the disadvantages of high operational temperatures. In this work, after introducing plasma classification and plasma chemistry, a comprehensive review of literature papers on non-thermal plasma-assisted methane coupling in the period 2010-2016 is presented and the best results that have been obtained with all different kinds of non-thermal plasma techniques are reported. Finally, as the energy cost is the main cost driver of the process after the raw material cost, comparison among all plasma techniques used for methane coupling is performed in terms of specific energy requirement to crack a mole of methane (SER, kJ/molCH4), efficiency (η %) and energy requirement to produce a mole of target product (ER, either kJ/molC2H2 or kJ/molC2H4). This is followed by a comparison between plasma-driven and thermal energy-driven methane coupling.

No abstract

No abstract

No abstract

Ultrasound-enhanced grinding is a more practical alternative to glass bead-enhanced grinding for performing attrition-enhanced deracemization at large scale or in continuous flow. In this work, both ultrasound-enhanced grinding (41.2 kHz) and glass bead-enhanced grinding were applied to induce Viedma deracemization of sodium chlorate (NaClO 3) crystals in isothermal conditions. The results demonstrate that high intensity, low frequency ultrasound can achieve efficient grinding of enantiomorphous NaClO 3 crystals, producing small crystal size and narrow size distribution, both being highly desirable final product properties. Monitoring the width of the crystal size distribution, reveals its crucial role and offers further insight on the underlying phenomena in the deracemization process. Compared to glass bead-enhanced grinding, ultrasound-enhanced grinding resulted in faster crystal size reduction, and rapid initial deracemization. However, further increase in the enantiomeric excess was hindered after prolonged times of ultrasonication. This ensues probably due to the absence of crystal sizeinduced solubility gradients, owing to the existence of close to monodispersed sized crystals after the initial stage in the ultrasound-enhanced grinding process. We show that this can be overcome by combining: a) ultrasound with glass beads, or b) ultrasound with seeding, both of which led to enantiopurity.

We present a helicopter view of microwave technology application to various reaction and separation processes, including liquid-phase organic syntheses, gas-solid catalytic reactions, polymerizations, extraction, distillation, crystallization, membrane separation, and adsorbent regeneration/dehydration. The overarching aim is to demonstrate the breadth of potential applications of microwave technology to chemical industry, with particular attention to separations, as this is a less explored microwave application area. In this context, some key findings, opinions, and developments in the relevant literature are summarized. In addition, the present microwave equipment concepts for chemical processes are critically reviewed and new ones are put forward, as we believe that an important milestone in the road from laboratory-scale microwave experimentation to industrial-scale microwave-assisted chemical processing is the design and development of innovative microwave equipment concepts tailored for specific chemical processes.

No abstract

No abstract