Methods for removing metallic and non-metallic impurities from hydrocarbon oils

Abstract

An embodiment of the invention is directed to a treatment method for reducing the level of metallic and nonmetallic impurities in an oil. The method includes the step of contacting the oil with a porous silica adsorbent material. The adsorbent material is characterized by a Brunauer-Emmett-Teller (BET) surface area value (total) of at least about 15 m2 / g; and a Barrett-Joyner-Halenda (BJH) pore volume (total) of at least about 0.5 cc / g.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates generally to processes for reducing impurity levels in organic compositions, such as oils. More particularly, the invention relates to the removal of metallic and non-metallic impurities from fuel oils, e.g., from crude oils.[0002]Hydrocarbon oils represent a type of crude oil (petroleum) found throughout the world, consisting of a complex mixture of hydrocarbons (mostly alkanes) of various lengths. In most cases, the hydrocarbon oils (e.g., the heavy oils) are processed and refined into other useful petroleum products, such as diesel fuel, gasoline, heating oil, kerosene, and liquefied petroleum gas.[0003]It is well known in the art that hydrocarbon oils, like other organic compositions derived prehistorically from nature, contain at least small amounts of contaminating metals, sulfur, and other elements and compounds, such as nitrogen. (Crude oil from regions such as Saudi Arabia often contains relatively high levels o...

AI Technical Summary

Problems solved by technology

The contaminants are detrimental to the direct use of the crude oil as a fuel (e.g., use of the oil with minimal processing), as well as being detrimental to the processing of the oil to produce other commercially valuable products.

As an illustration in the case of gas turbine engines which may use this type of oil as a fuel, the impurities can cause serious corrosion problems on the turbine blades and other components.

More specifically, vanadium compounds which form hard deposits on turbine blades are known to promote serious corrosion.

In addition to causing material degradation and processing problems in refineries, the presence of contaminants like sulfur (usually in organic form) can also result in serious environmental and regulatory problems.

For these reasons, gas turbine engines and other equipment may not always be capable of efficient operation when running on this type of fuel oil.

However, distillation techniques can be very energy-intensive; and may not be suitable for removing contaminants from the heavy, “bottom” fractions of crude oil.

However, vanadium and nickel impurities which are also present in the oil tend to adhere to the catalysts and thereby block the active site, diminishing the efficiency of the desulfurization reactions.

The heavy oils are treated by contact with a methylating agent, such as dimethyl sulfate, resulting in the formation of precipitates which include the contaminants.

While the use of the magnesium compounds may be suitable in some situations, there are limitations in other situations.

For example, the compounds may form excessively hard deposits if the underlying part (for example, a gas turbine) is exposed to higher temperatures, e.g., greater than about 2,000° F.

In that case, the problem of deposits adhering to the metal surface remains.

Thus, use of the gas turbine component may have to be restricted to lower operating temperatures, and this limitation can also represent a significant drawback.

Moreover, combustion of the lower-melting magnesium-vanadium alloys can result in the generation of significant amounts of ash, which also forms a residue on an underlying substrate, e.g., the turbine blades.

These deposits can adversely affect the gas flow path over the turbine blades.

Furthermore, cleaning steps to remove the deposits may require temporarily shutting down the turbine, which will also lower power-generation efficiency.