In a process for the catalytic conversion of lower hydrocarbons to aromatic compounds comprising benzene, toluene and xylenes, a process stream containing lower hydrocarbons is contacted with a zeolitic catalyst having an MFI framework and containing 0.1 to 10 percent by weight of a zinc compound. The process stream further contains one or more sulfur compounds, especially hydrogen sulfide, for improving the selectivity.

Systems and methods for purifying crude propane streams are provided herein. For example, in some embodiments, methods are provided including passing a crude propane stream to a fixed bed reactor containing a Beta zeolite configured to reduce the propylene oxide content of the crude propane stream and produce a propylene-treated stream and contacting the propylene-treated stream with an acetaldehyde scavenger to produce a treated propane stream. In some embodiments, methods are provided including passing a crude propane stream through a water wash system to provide a treated propane stream having a lower propylene oxide content, a lower acetaldehyde content, or both.

Systems and methods for purifying crude propane streams are provided herein. For example, in some embodiments, methods are provided including passing a crude propane stream to a fixed bed reactor containing a Beta zeolite configured to reduce the propylene oxide content of the crude propane stream and produce a propylene-treated stream and contacting the propylene-treated stream with an acetaldehyde scavenger to produce a treated propane stream. In some embodiments, methods are provided including passing a crude propane stream through a water wash system to provide a treated propane stream having a lower propylene oxide content, a lower acetaldehyde content, or both.

A process and apparatus for reducing the sulfur content of naphtha. The process includes introducing at least a portion of a naphtha feed stream to a selective hydrodesulfurization zone under selective hydrodesulfurization conditions in the presence of a selective hydrodesulfurization catalyst to form a low sulfur stream which contains mercaptan and thiophene compounds. At least a portion of the low sulfur stream is separated into at least two streams, a mercaptan rich stream containing mercaptan and thiophene compounds and an overhead stream containing hydrogen sulfide and liquid petroleum gas. The mercaptan rich stream is treated in an adsorbent zone to remove at least a portion of the mercaptan and thiophene compounds to form a mercaptan lean stream.

A process and apparatus for reducing the sulfur content of naphtha. The process includes introducing at least a portion of a naphtha feed stream to a selective hydrodesulfurization zone under selective hydrodesulfurization conditions in the presence of a selective hydrodesulfurization catalyst to form a low sulfur stream which contains mercaptan and thiophene compounds. At least a portion of the low sulfur stream is separated into at least two streams, a mercaptan rich stream containing mercaptan and thiophene compounds and an overhead stream containing hydrogen sulfide and liquid petroleum gas. The mercaptan rich stream is treated in an adsorbent zone to remove at least a portion of the mercaptan and thiophene compounds to form a mercaptan lean stream.

A process and apparatus for reducing the sulfur content of naphtha. The process includes introducing at least a portion of a naphtha feed stream to a selective hydrodesulfurization zone under selective hydrodesulfurization conditions in the presence of a selective hydrodesulfurization catalyst to form a low sulfur stream which contains mercaptan and thiophene compounds. At least a portion of the low sulfur stream is separated into at least two streams, a mercaptan rich stream containing mercaptan and thiophene compounds and an overhead stream containing hydrogen sulfide and liquid petroleum gas. The mercaptan rich stream is treated in an adsorbent zone to remove at least a portion of the mercaptan and thiophene compounds to form a mercaptan lean stream.

The invention relates to a process for obtaining isobutene from an isobutene containing C4-hydrocarbon mixture (1) in a plant comprising an etherification unit (3), a first distillation unit (5), an ether cleavage unit (8) and a second distillation unit (10), the process comprising: (a) contacting the C4-hydrocarbon mixture (1) with a primary alcohol (2) and reacting the mixture with the primary alcohol in the presence of an acidic catalyst to form the corresponding alkyl tert-butyl ether as an intermediate product and diisobutene as a by-product in the etherification unit (3); (b) distilling the reaction mixture (4) from the etherification unit (3) in the first distillation unit (5), a C4-hydrocarbon raffinate being withdrawn as the overhead product (6), the alkyl tert-butyl ether and diisobutene being withdrawn as the liquid or vaporous bottom product (7), and vaporizing the bottom product (7) if it is withdrawn as a liquid; (c) reacting the vaporous bottom product (7) in the presence of an acidic catalyst obtaining isobutene and the primary alcohol as reaction products in the ether cleavage unit (8); (d) distilling the reaction mixture (9) from the ether cleavage unit (8) in the second distillation unit (10), isobutene being withdrawn as the overhead product (11), the primary alcohol and diisobutene being withdrawn as the bottom product (12) and being recycled to the etherification unit (3); the plant further comprising a byproduct separation unit (15) being fed by a bottom purge stream (13) of the first distillation unit (5) and/or by a part of the bottom product of the second distillation unit (10), this feed stream (14) being split up in at least three byproduct streams wherein a first byproduct stream (16) is rich in diisobutene, a second byproduct stream (17) is rich in the primary alcohol, and a third byproduct stream (18) is rich in components with a normal boiling point higher than 110? C.

The present invention relates generally to methods and systems for removing oxygen from at least one product stream of a hydrocarbon oxidative dehydrogenation process. More specifically, in some embodiments, the oxidative dehydrogenation process is an ethane oxidative dehydrogenation process for producing ethylene, or a mixed alkane oxidative dehydrogenation process for producing ethylene and propylene, among other components.

Treatment of hydrocarbon streams, and in one non-limiting embodiment refinery distillates, with high pH aqueous reducing agents, such as borohydride, results in reduction of the sulfur compounds such as disulfides, mercaptans and thioethers that are present to give easily removed sulfides. The treatment converts the original sulfur compounds into hydrogen sulfide or low molecular weight mercaptans that can be extracted from the distillate with caustic solutions, hydrogen sulfide or mercaptan scavengers, solid absorbents such as clay or activated carbon or liquid absorbents such as amine-aldehyde condensates and/or aqueous aldehydes.

The presently disclosed subject matter relates to methods and systems for purifying 1,3-butadiene from a C4 hydrocarbon stream. An example method includes introducing a C4 hydrocarbon stream including 1,3-butadiene and acetlyenes to an organic azide in the presence of a catalyst to generate a first stream including triazole, separating triazole from the first stream to produce a second stream including 1,3-butadiene, and distilling 1,3-butadiene from the second stream to produce a purified 1,3-butadiene product stream.