Integrated hydrotreating and steam pyrolysis process for direct processing of a crude oil

Abstract

An integrated hydrotreating and steam pyrolysis process for the direct processing of a crude oil is provided to produce olefinic and aromatic petrochemicals. Crude oil and hydrogen are charged to a hydroprocessing zone operating under conditions effective to produce a hydroprocessed effluent reduced having a reduced content of contaminants, an increased paraffinicity, reduced Bureau of Mines Correlation Index, and an increased American Petroleum Institute gravity. Hydroprocessed effluent is thermally cracked in the presence of steam to produce a mixed product stream, which is separated. Hydrogen from the mixed product stream is purified and recycled to the hydroprocessing zone, and olefins and aromatics are recovered from the separated mixed product stream.

Description

RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Patent Application No. 61 / 591,811 filed Jan. 27, 2012, the disclosure of which is hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to an integrated hydrotreating and steam pyrolysis process for direct processing of a crude oil to produce petrochemicals such as olefins and aromatics.[0004]2. Description of Related Art[0005]The lower olefins (i.e., ethylene, propylene, butylene and butadiene) and aromatics (i.e., benzene, toluene and xylene) are basic intermediates which are widely used in the petrochemical and chemical industries. Thermal cracking, or steam pyrolysis, is a major type of process for forming these materials, typically in the presence of steam, and in the absence of oxygen. Feedstocks for steam pyrolysis can include petroleum gases and distillates such as naphtha, kerosene and gas oil. The availab...

AI Technical Summary

Benefits of technology

The patent describes a process for making petrochemicals from crude oil. The process involves hydrotreating the crude oil to remove impurities, adding hydrogen to increase its paraffinicity, reducing its ultramobile content, and increasing its API gravity. The hydrotreated oil is then thermally cracked in the presence of steam to produce a mixture of products. Hydrogen is purified from this mixture and recycled back to the hydrotreating zone, while the desired petrochemicals are recovered from the separated mixture. This process helps produce high-quality olefins and aromatics from crude oil.

Problems solved by technology

The availability of these feedstocks is usually limited and requires costly and energy-intensive process steps in a crude oil refinery.

A major drawback in conventional heavy hydrocarbon pyrolysis operations is coke formation.

In a comparative example without the addition of molten salt, the steam cracking reactor became clogged and inoperable after just 5 hours because of the formation of coke in the reactor.

While the steam pyrolysis process is well developed and suitable for its intended purposes, the choice of feedstocks has been very limited.

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