Process for sulfone conversion by super electron donors

Abstract

A process wherein an electron donor agent is provided for the decomposition of sulfones and sulfoxides formed after the oxidative desulfurization of a sulfur-containing hydrocarbon stream.

Description

FIELD OF THE INVENTION[0001]The process of the present invention relates to the removal of oxidized sulfur-containing compounds after the oxidative desulfurization of a crude oil or distilled oil, or an integrated hydrodesulfurization / oxidative desulfurization. More particularly, it relates to a process for the decomposition of remaining sulfones and sulfoxides after oxidative desulfurization.BACKGROUND OF THE INVENTION[0002]Crude oil is the world's main source of hydrocarbons used as fuel and petrochemical feedstock. While compositions of natural petroleum or crude oils are significantly varied, all crudes contain sulfur compounds and most contain nitrogen compounds which may also contain oxygen, but oxygen content of most crude is low. Generally, the sulfur concentration in crude oils is less than about 5 weight percent, with most crude having sulfur concentrations in the range from about 0.5 to about 1.5, weight percent. Nitrogen concentration is usually less than 0.2 weight perc...

AI Technical Summary

Benefits of technology

The present invention is a method for upgrading hydrocarbon feedstocks by removing sulfones and sulfoxides. The method involves oxidizing sulfur compounds in the feedstock to produce an oxidized sulfur-containing hydrocarbon stream, which is then separated from an aqueous phase. The non-aqueous oxidized effluent is contacted with an electron donor agent to oxidize sulfones and sulfoxides present in the effluent. The hydrocarbon stream, which has had the sulfones and sulfoxides removed, is then separated and recovered. The technical effects of this invention include reductive cleavage of carbon-to-sulfur bonds in sulfones and sulfoxides using electron donor agents and improved quality of the upgraded hydrocarbon feedstock.

Problems solved by technology

Sulfur-containing organic compounds in fuels are, indeed, a major source of environmental pollution.

However, most compounds of this type have high vapor pressure and / or are nearly insoluble in diesel fuel, and they have poor ignition quality, as indicated by their cetane numbers.

Diesel fuels of low lubricity may cause excessive wear of fuel pumps, injectors and other moving parts which come in contact with the fuel under high pressures.

These units are not efficient at mild conditions (i.e., 30 bars pressure) to remove sulfur from compounds where the sulfur atom is sterically hindered as in multi-ring aromatic sulfur compounds.

The increase of hydrogen partial pressure can only be done by increasing the recycle gas purity, or new grassroots units must be designed, which is a costly option.

The use of severe operating conditions results in yield loss, less catalyst cycle and product quality deterioration (e.g., color).

The aliphatic sulfur compounds are easily desulfurized using the hydrodesulfurization method but some of the highly branched aliphatic molecules can hinder the sulfur atom removal and are moderately harder to desulfurize.

Among the sulfur-containing aromatic compounds, thiophenes and benzothiophenes are relatively easy to hydrodesulfurize, while the addition of alkyl groups to the ring compounds slightly increases the difficulty of hydrodesulfurization.

Dibenzothiophenes resulting from adding another ring to the benzothiophene family are directionally harder to desulfurize and the difficulty varies greatly according to their alkyl substitution with di-beta substitution being the most difficult to desulfurize, justifying their “refractory” appellation.

The economical removal of the so-called “refractory sulfur” is thus exceedingly difficult to achieve and, therefore, the removal of sulfur compounds in hydrocarbonaceous fuels to a sulfur level below about 10 ppmw is very costly by current hydrotreating techniques.

However, no efficient methods have been proposed for the ultimate disposal of the sulfoxides and sulfones.

The reference, however, provides no teaching on the methods for ultimate disposal of the oxidized sulfur compounds.

However, some of the sulfones compounds formed are reduced back to the initial sulfur compounds still leaving the sulfur disposal problem not fully resolved.

However, not all the distillate feedstream is recovered to obtain a low sulfur distillate fuel product.

This was a limited study, however, which was only done with model compounds.

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