Ionic Liquids in Refinery Desulfurization: Comparison between Biphasic and Supported Ionic Liquid Phase Suspension Processes

Abstract

The desulfurization of fuel compounds in the presence of ionic liquids is reported. For this purpose, the desulfurization efficiency of a variety of imidazolium phosphate ionic liquids has been tested. Dibenzothiophene/dodecane and butylmercaptan/decane mixtures were used as model systems. Single-stage extractions reduced the sulfur content from 500 ppm to 200 ppm. In multistage extractions the sulfur content could be lowered to less than 10 ppm within seven stages. Regeneration of the ionic liquid was achieved by distillation or re-extraction procedures. Supported ionic liquid phase (SILP) materials, obtained by dispersing the ionic liquid as a thin film on highly porous silica, exhibited a significantly higher extraction performance owing to their larger surface areas, reducing the sulfur content to less than 100 ppm in one stage. Multistage extraction with these SILP materials reduced the sulfur level to 50 ppm in the second stage. The SILP technology offers very efficient utilization of ionic liquids and circumvents mass transport limitations because of the small film thickness and large surface area, and allows application of the simple packed-bed column extraction technique.

CO2 Capture Using Silica and Molecular Sieve Impregnated with [hmim][Tf2N]

“…As to our knowledge, solid supported ionic liquid has been studied in desulfurization [7] and also as a catalyst, for example in the Friedel-Crafts reactions, however, for gas separation, ionic liquids are usually supported onto membrane to increase the permeability of gas through the membrane [8]. Therefore, in this research, ionic liquid was supported onto silica dioxide as to provide more available data for porous solid supported ionic liquids in the gas separation application.…”

Effects of Ionic Liquids and Supports on the Permeation of Organic Nitrogen Compounds through Supported Ionic Liquid Membranes

“…Imidazolium-based ionic liquids were prepared from the bromides of 1-n-butyl-, 1-n-hexyl-, and 1-n-octyl-3-methyl imidazolium, [C 4 6 ], of 1-n-hexyl-3-methyl imidazolium as reported previously [11]. 1-Ethyl-3-methyl imidazolium ethylsulfate, [12].…”

“…Methods based on solvent extraction have been proposed [4,5] with the advantages of low energy cost, elimination of hydrogen usage, retention of the chemical structures of the fuels, and no special equipment requirements [5]. Recently, desulfurization and denitrogenation have been investigated with solvent extraction [6][7][8] and supported liquid membranes (SLM) [9,10] using ionic liquids.…”

Current Knowledge and Potential Applications of Ionic Liquids in the Petroleum Industry

“…All latter approaches use biphasic extraction where surface area is poor, mass-transfer issues should be important and require a lot of ILs recycling steps. Recently, the use of ILs deposited on a solid, known as supported ionic liquid phase (SILP), incremented significantly the desulfurization efficiency by augmenting surface area, diminishing mass-transfer problems and allowing a continuous process (Kuhlmann et al, 2009). Careful attention must be paid to ILs leaching or saturation during process, but ILs chemical bonding to support as well as ILs-support reactivation are subjects that must be further studied.…”