The difficulties associated with transportation and refining of crude oil emulsions as well as produced water discharge limitations are among the conspicuous clues that have led the oilfield researchers to probe into practical demulsification methods for many decades.Inconsistent research outcomes observed in the literature for a particular demulsification method of a typical emulsion (i.e., water-in-oil or oil-in-water) arise not only from the varied influential parameters associated (such as salinity, temperature, pH, dispersed phase content, emulsifier/demulsifier concentration, droplet size, etc.), but also from the diverse types of emulsion constituents (namely oil, surfactant, salt, alkali, polymer, fine solids, and/or other chemicals/impurities). Being the main component in formation of stabilizing interfacial film surrounding the dispersed phase droplets, surfactant is the most predominant contributor to emulsion stability, extent of which depends on its nature (being ionic or nonionic, and its degree of hydrophilicity/lipophilicity), concentration and interaction with other surface-active agents in the emulsion, as well as on the salinity, temperature, and pH of the system. In this paper, it is endeavored to overview some of the most commonly exploited demulsification techniques (i.e., chemical, biological, membrane, electrical, and microwave irradiation) on both the oilfield and synthetic emulsions, taking into account the emulsion-stabilizing anddestabilizing effects with regard to the dominant parameters plus the emulsion composition.Further, the variations occurring in interfacial properties of emulsions by demulsification process are discussed. Finally, the mechanism(s) involved in emulsions resolution achieved by each method is elucidated. Clearly, the most efficient demulsification approach is the one able to attain desirable separation efficiency while complying with the environmental regulations and imposing the least economic burden on the petroleum industry.

This paper highlights the use of a dual fluidized bed reactor system for producing hydrogen by sorption-enhanced steam methane reforming. Hydrogen concentrations of >98% are predicted for temperatures of ∼600 °C and a superficial gas velocity of 0.1 m/s, using a simple two-phase bubbling bed model for the reformer. The kinetics of the steam methane reforming and water-gas shift reactions are based on literature values, whereas experimentally derived carbonation kinetics are used for the carbonation of a dolomite. It is shown that the reformer temperature should not be <540 °C or >630 °C for carbon capture efficiencies to exceed 90%. Operating at relatively high solids circulation rates to reduce the need for fresh sorbent is predicted to give higher system efficiencies than for the case where fresh solid is added. This finding is attributed to the additional energy required to decompose both CaCO3 and MgCO3 in fresh dolomite.

In the present investigation a realistic two‐phase model accounting for the change in the total number of moles accompanying the reaction is utilized to explore a novel reactor configuration suggested for the methane steam reforming process. The suggested design is basically a fluidized bed reactor equipped with a bundle of membrane tubes. These tubes remove the main product, hydrogen, from the reacting gas mixture and drive the reaction beyond its thermodynamic equilibrium. The proposed novel design is also equipped with sodium heat pipes which act as a thermal flux transformer to provide the large amount of heat needed by the endothermic reaction through a relatively small heat transfer surface, assuring better reactor compactness. Two options for fluid routing through the membrane tubes are proposed; each is suitable for a certain industrial application. The performance of this novel configuration is compared with that of an industrial fixed bed steam reformer and the comparison shows the potential advantages of the suggested configuration.