Demulsification of Kerosene/Water Emulsion in the Transparent Asymmetric Plate-Type Micro-Channel

Abstract

Asymmetric plate-type micro-channels (APM) have one hydrophobic wall and one hydrophilic wall. By flowing through APM, a kerosene-in-water emulsion can be de-emulsified in one second. To date, however, the demulsification process in the APM is still a black box. In order to observe the demulsification process directly, transparent asymmetric plate-type micro-channels (TAPM) were fabricated with two surface-modified glass plates. Emulsions with oil contents of 10%, 30%, and 50% were pumped through TAPM with heights of 39.2 μm and 159.5 μm. The movement and coalescence of oil droplets (the dispersed phase of a kerosene-in-water emulsion) in the TAPM were observed directly with an optical microscope. By analyzing videos and photographs, it was found that the demulsification process included three steps: oil droplets flowed against and were adsorbed on the hydrophobic wall, then oil droplets coalesced to form larger droplets, whereupon the oil phase was separated. The experimental results showed that the demulsification efficiency was approximately proportional to the oil content (30–50%) of the emulsions and increased when the micro-channel height was reduced.

Emulsion Liquid Membrane Extraction of Bisphenol A with Three-dimensional Spiral Plate-type Microchannel

“…At both ends along the arrangement line, there were two pieces of stainless steel end plates, which were 5 mm in-depth and with two orifices of entrance and exit. For the manufacturing details of 3D-SPM, please refer to our previous article [10,13,14].…”

“…Microfluidics has the intrinsic advantage of process intensification for its Micron-scale channel size. In the areas of heat exchange [9], separation [10], reaction [11] and extraction [12], microfluidics shows its high efficiency and shorts the time for these unit operations from hours to minutes or seconds. If the resident time for ELMs extracting BPA was shortened to be seconds, the quantity of emulsifier will be decreased and the process for extraction and demulsification could be simple, which will make all the ELMs extraction process to be more simple, continuous, economical and environmentallyfriendly.…”

Universal Rapid Demulsification by Vacuum Suction Using Superamphiphilic and Underliquid Superamphiphobic Polyurethane/Diatomite Composites

“…1−4 In China, the chemical oxygen demand (COD) of wastewater must be less than 50 mg/L according to the Chinese discharge standard of pollutants for municipal wastewater treatment plants, GB18919-2002; thus, the residual oil content of wastewater must be as low as possible. Various methods such as gravity separation, 5,6 local combustion, 7 chemical demulsification, 8 coalescence separation, 9,10 microchannel demulsification, 11 membrane separation, 12−16 and adsorption separation 13,17 are commonly employed to treat emulsions. However, inexpensive and satisfactory emulsion treatment is difficult to achieve owing to the natural drawbacks of these conventional processes: easy choking and contamination of the membrane and coalescer by oil fouling, the high cost of operational energy consumption and the demulsifier, or frequent adsorbent replacement.…”

“…Oil/water emulsions, a common type of oily wastewater, are widely present in daily life and industrial production and must be treated before discharge. − In China, the chemical oxygen demand (COD) of wastewater must be less than 50 mg/L according to the Chinese discharge standard of pollutants for municipal wastewater treatment plants, GB18919-2002; thus, the residual oil content of wastewater must be as low as possible. Various methods such as gravity separation, , local combustion, chemical demulsification, coalescence separation, , microchannel demulsification, membrane separation, − and adsorption separation , are commonly employed to treat emulsions. However, inexpensive and satisfactory emulsion treatment is difficult to achieve owing to the natural drawbacks of these conventional processes: easy choking and contamination of the membrane and coalescer by oil fouling, the high cost of operational energy consumption and the demulsifier, or frequent adsorbent replacement. − Thus, it is necessary to develop a simple, low-cost continuous emulsion separation process based on a facile, fast, stable, and efficient demulsifying separator with low energy consumption, low cost, high environmental friendliness without the use of external chemicals, and excellent oil fouling tolerance in long-term operation.…”

Elaboration of the Demulsification Process of W/O Emulsion with Three-Dimensional Electric Spiral Plate-Type Microchannel

“…Peter Thurgood et al studied the law of vortex generated by microstructures on particle migration and aggregation by adding U-shaped and spherical microstructures in microchannels [29,30]. When the emulsion flows within the microchannel, the hydraulic equilibrium is used to concentrate the droplets in a certain area, thereby increasing the probability of aggregation between the droplets [31,32,33,34].…”