Finishing of Diesel Fuel to Remove Sulfur Compounds after Hydrotreating

Abstract

A method for finishing hydrotreated diesel fuel to remove sulfur compounds in two stages is described. In the first stage, sulfur compounds remaining in the fuel are oxidized into sulfones with hydrogen peroxide in the presence of molybdenum compounds and in the second stage, the sulfones are decomposed into sulfur dioxide and hydrocarbon on aluminosilicate catalyst. The fuel obtained satisfies the new European standards for sulfur content.Most European states have switched to using diesel fuels that satisfy the requirements of EN 590 for the sulfur content: a maximum of 350 ppm [1]. These requirements are even stiffer in the USA [2]. Domestic diesel fuels after hydrotreating units contain 500-2000 ppm total sulfur [3]. In this respect, developing better and cheaper methods of treating fuels with oxidation reactions is very urgent [4].We previously [5] described a method for finishing hydrotreated diesel fuel to remove sulfur in two stages. In the first stage, the sulfur compounds remaining in the hydrogenation product are oxidized into sulfones with hydrogen peroxide in foam-emulsion conditions in the presence of acids, and in the second stage, the sulfones are extracted from the oxidate by adsorption with silica gel. However, the acids used as catalyst corrode the equipment, and controlling this corrosion requires additional outlays, which makes industrial introduction of the process difficult. In addition, in treating the oxidate to remove sulfones, difficult to utilize spent adsorbent is formed.To eliminate acids and spent adsorbent from the technology, oxidation of the sulfur compounds in the hydrogenation product into sulfones with hydrogen peroxide was investigated in foam-emulsion conditions in the presence of metal compounds, followed by catalytic decomposition of the sulfones into sulfur dioxide and a hydrocarbon.The experimental foam-emulsion oxidation setup was described in [6]. The feedstock was loaded together with the catalyst into the reactor with air feed and as the assigned temperature was attained, hydrogen peroxide

Oxidative processes of desulfurization of liquid fuels

“…40,[48][49][50][51][52][53][54][55][56][57] Working under these reaction conditions, the reaction time can be reduced to less than 2 h. However, these reaction times are still too high to be integrated in a refinery. The main problem is related to the presence of two reaction phases:…”

Oxidative Methods of Desulfurization Of Diesel Fuels: Results, Problems, Perspective

“…The main industrial methods for desulphurization of crude oil are hydrogenation processes, including a combination of catalytic refining processes such as hydrodesulphurization, hydrodeazotization, hydrodemetallization [1,8,11,16,21,22,[30][31][32].…”

“…These technologies are represented by the following processes: oxidative desulfurization, biological methods, ozonolysis, unconventional methods of processing raw materials and the resulting fuels (magnetic, ultrasonic and other wave effects) or a combination of these methods [4,17,31,32].…”

“…Over the past decade, the methods of oxidative desulfurization have progressed greatly, and many research papers have been devoted to this issue, including a number of reviews by national and international authors [4,[24][25][26][27][28][29][30][31][32][33][34][35][36].…”

“…The most common oxidizing agents of organic sulfur compounds include hydrogen peroxide [31,[32][33][34] and organic hydroperoxides [35,36]: alkyl hydroperoxides, cyclohexanone peroxide, tert-butyl hydroperoxide, tert-butyl hydroperoxide, etc. The extractants of sulfoxides removal and sulfonic nitrate are distilled acetone solution [35].…”