Multicycle Investigation of Normal Paraffin Separation from Naphtha To Improve Olefin and Aromatic Feed

Recent Developments in Solvent-Based Fluid Separations

The most important developments in solvent-based fluid separations, separations involving at least one fluid phase, are reviewed. After a brief introduction and discussion on general solvent trends observed in all fields of application, several specific fields are discussed. Important solvent trends include replacement of traditional molecular solvents by ionic liquids and deep eutectic solvents and, more recently, increasing discussion around bio-based solvents in some application fields. Furthermore, stimuli-responsive systems are discussed; the most significant developments in this field are seen for CO₂-switchable and redox-responsive solvents. Discussed fields of application include hydrocarbons separations, carbon capture, biorefineries, and metals separations. For all but the hydrocarbons separations, newly reported electrochemically mediated separations seem to offer exciting new windows of opportunities.

A Bibliometric Survey of Paraffin/Olefin Separation Using Membranes

Bibliometric studies allow to collect, organize and process information that can be used to guide the development of research and innovation and to provide basis for decision-making. Paraffin/olefin separations constitute an important industrial issue because cryogenic separation methods are frequently needed in industrial sites and are very expensive. As a consequence, the use of membrane separation processes has been extensively encouraged and has become an attractive alternative for commercial separation processes, as this may lead to reduction of production costs, equipment size, energy consumption and waste generation. For these reasons, a bibliometric survey of paraffin/olefin membrane separation processes is carried out in the present study in order to evaluate the maturity of the technology for this specific application. Although different studies have proposed the use of distinct alternatives for olefin/paraffin separations, the present work makes clear that consensus has yet to be reached among researchers and technicians regarding the specific membranes and operation conditions that will make these processes scalable for large-scale commercial applications.

Adsorptive Removal of Acetaldehyde from Propylene Oxide Produced by the Hydrogen Peroxide to Propylene Oxide Process

Adsorption method was first introduced into the propene oxide production via hydrogen peroxide process to remove the microimpurity in the propylene oxide (PO) product solution. It could replace the reactive distillation in separating acetaldehyde with less energy consumption and PO loss. A series of adsorbents (e.g., 3A, 4A, 5A, 10X, and Y) are first used to remove the impurity (i.e., acetaldehyde). It is found that 5A molecular sieves shows the best performance due to uniform porous channels with suitable pore size. Various techniques such as X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared, and N₂ physisorption are employed to investigate the structural properties of the adsorbent. Furthermore, effects of space velocity and temperature are also investigated. Cyclic desorption and adsorption tests indicate the PO yield is 92.2%, and 96.3% of acetaldehyde was removed. The acetaldehyde concentration of PO product was 0.0187%, indicating this method can produce industrial-quality PO that meets the first-level technical requirements.

Temperature-induced deactivation mechanism of ZnFe2O4 for oxidative dehydrogenation of 1-butene

This paper describes the observation of an irregular decrease in 1-butene conversion during oxidative dehydrogenation over ZnFe₂O₄ in the production of 1,3-butadiene upon increasing the reaction temperature above 400 °C.