Cyclic petroleum refining

Abstract

Heat from solar or nuclear heat sources is applied to provide at least a portion of the heat used in a cyclic petroleum refining process in which a hydrocarbon feedstream is contacted with a solid particulate contact material in a first step to treat the feedstream after which the solid contact material is separated or disengaged from the treated feedstream and regenerated in a separate regeneration zone before being returned to the first step for contact with additional feedstream. The entire cycle may be characterized as including an endothermic step, generally a reduction, and an exothermic step, generally an oxidation, with heat from the exothermic step being transferred from the exothermic step to the endothermic step by means of the circulating contact material. The application of the nuclear or solar heat may be applied to whichever step of the process requires heat from external sources. This technique may be applied to a method of regenerating catalysts and sorbents used in gas refining processes for removing contaminants from hydrocarbons and other gases including natural gas and syngas as well as to the FCC process.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application relates and claims priority to U.S. Provisional Patent Application No. 61 / 268,777, filed on Jun. 16, 2009.FIELD OF THE INVENTION[0002]This invention relates to cyclic petroleum refining processes in which a hydrocarbon feedstream is contacted with a solid, particulate contact material in a first step to treat the feedstream after which the solid contact material is separated or disengaged from the treated feedstream and regenerated in a separate regeneration zone before being returned to the first step for contact with additional feedstream. The invention concerns itself particularly with the provision of external process heat to one or both steps of the process using solar and / or nuclear heat sources.BACKGROUND OF THE INVENTION[0003]The petroleum refinery is one of the most thoroughly integrated operations devised by the mind of man: apart from contaminants, all that goes into the refinery is either consumed in processin...

AI Technical Summary

Benefits of technology

[0011]The present invention therefore comprehends a cyclic petroleum refining process in which a hydrocarbon feedstream is contacted with a solid, particulate contact material in a first step to treat the feedstream after which the solid contact material is separated from the treated feedstream and regenerated in a separate regeneration zone before being returned to the first step for contact with additional feedstream. At least one of the steps is carried out at elevated temperature provided by the application of heat from a nuclear or solar thermal energy source. The use of heat from solar and nuclear heat sources is especially favorable in cases where very high operating temperatures, typically above about 800° C. or higher, e.g. 950 or 1,000° C., are required.

[0013]The solar or nuclear heat is applied by the use of a heat transfer medium and heat exchange device transferring the heat from the solar or nuclear power source to the process unit in which the process is being operated. The heat transfer medium will be routed from the solar or nuclear source to a heat exchanger providing pre-heat for the process, direct heat to the process environment e.g. by a heating jacket on the reactor used for carrying out the process or by heat transfer coils or tubes inside the reactor. Solar and nuclear heat sources have the capability to generate very high temperatures potentially in excess of 1500° C. and heat of this quality can be used very effectively to provide process heat to the endothermic reaction steps of the cyclic chemical processes, even when transferring heat to reactant gas streams in a heat exchanger. Heat transfer can be effected using transfer media such as liquids, gases, molten salts or molten metals although molten salts and molten metals will often be preferred for their ability to operate at very high temperatures for high energy densities without phase changes; in addition, corrosion problems can be minimized by appropriate choice of medium relative to the metallurgy of the relevant units.

[0014]Solar and nuclear thermal energy sources are zero carbon emission sources and by using them hydrocarbon resource utilization for process heat is eliminated. Carbon dioxide evolution associated with burning of a hydrocarbon resource to generate process heat is eliminated. For perspective, each liter of petroleum resid requires approximately 140 liters of natural gas (methane at 15.5° C.) to heat it to 540° C. and hold it at that temperature for six seconds and, as noted above, about 20 to 25 percent of the crude oil input to a refinery is used in processing. The substitution of zero carbon emission sources therefore offers the potential for significant carbon emission reductions in refinery operations where external process hear can be applied and effectively utilized.

Problems solved by technology

While conventional technology including extraction processes such as the Merox™ processes, oxidation and hydrodesulfurization have long fulfilled the requirements the future regulatory trans towards even lower sulfur levels may make it uneconomic or, in fact, impossible to use them.

Another difficulty confronting the refiner in fuel oil production is that certain sulfur compounds such as the sterically hindered alkyl-substituted benzothiophenes and dibenzothiophenes are not readily amenable to hydrogenative treatment.