The invention concerns a catalytic composition comprising: at least one nickel precursor with an oxidation number of (+II), at least one phosphine ligand with formula PR.sup.1R.sup.2R.sup.3 in which the groups R.sup.1, R.sup.2 and R.sup.3, which may be identical or different and which may or may not be bonded together, and at least one Lewis base, said composition having a molar ratio of the phosphine ligand to the nickel precursor of less than or equal to 5 and a molar ratio of the Lewis base and phosphine ligand together to the nickel precursor of greater than or equal to 5.

Systems and methods are provided for catalyst regeneration using a stoichiometric amount or less air for coke combustion.

Systems and methods conducive to the formation of one or more alkene hydrocarbons using a methane source and an oxidant in an oxidative coupling of methane (OCM) reaction are provided. One or more vessels each containing one or more catalyst beds containing one or more catalysts each having similar or differing chemical composition or physical form may be used. The one or more catalyst beds may be operated under a variety of conditions. At least a portion of the catalyst beds may be operated under substantially adiabatic conditions. At least a portion of the catalyst beds may be operated under substantially isothermal conditions.

A process, a system, and an apparatus for separation of an oxygenate from a stream is provided. More specifically, a stream comprising the oxygenate is introduced to a quench tower along with a caustic outlet stream comprising a metal salt. Contact between the oxygenate and the metal salt results in conversion of a portion of the oxygenate into a derivative salt. The derivative salt and unconverted oxygenate are condensed by quenching and substantially removed from the quench tower as an oxygenate outlet stream. The gaseous components of the stream, minus a substantial portion of the oxygenate, are removed from the quench tower as a quench outlet stream.

A method of treating a hydrocarbon stream includes: withdrawing an effluent stream comprising hydrocarbons and polymer from a reactor; contacting the effluent stream with a coolant stream; passing the effluent stream through a heat exchanger; wherein after passing the effluent stream through the heat exchanger, the heat exchanger is substantially free of polymer deposits.

Systems and a method for manufacturing a base stock from a hydrocarbon stream are provided. An example method includes cracking the hydrocarbon stream to form a raw product stream, separating an ethylene stream from the raw product stream, and oligomerizing the ethylene stream to form a raw oligomer stream. A Light olefinic stream is distilled from the raw oligomer stream and oligomerized the light olefinic stream with the ethylene stream. A heavy olefinic stream is distilled from the raw oligomer stream. The heavy olefinic stream is to form a hydro-processed and distilled to form the base stock.

A process for producing transport fuel blendstocks comprises providing a first feedstock comprising butane and propane and a second feedstock comprising benzene and dehydrogenating the first feedstock in a first reactor to produce a C4 product comprising butane and butene and a C3 product comprising propane and propylene. The process also comprises oligomerizing the C4 product in a second reactor to produce a first transport fuel blendstock and alkylating the C3 product with the second feedstock in a third reactor to produce a second transport fuel blendstock.

Improved alkylation catalysts, alkylation methods, and methods of making alkylation catalysts are described. The alkylation method comprises reaction over a solid acid, zeolite-based catalyst and can be conducted for relatively long periods at steady state conditions. The alkylation catalyst comprises a crystalline zeolite structure, a Si/Al molar ratio of 20 or less, less than 0.5 weight percent alkali metals, and further having a characteristic catalyst life property. Some catalysts may contain rare earth elements in the range of 10 to 35 wt %. One method of making a catalyst includes a calcination step following exchange of the rare earth element(s) conducted at a temperature of at least 575 C. to stabilize the resulting structure followed by an deammoniation treatment. An improved method of deammoniation uses low temperature oxidation.

The present disclosure provides methods and materials for oligomerization of lower olefins (e.g., C.sub.2-C.sub.8) to transportations fuels including diesel and/or jet fuel. The oligomerization employs, in certain embodiments, tungstated zirconium catalysts. Surprisingly, the oligomerizations proceed smoothly in high yields and exhibit little to no sensitivity to the presence of significant amounts of oxygenates (e.g., water, lower alcohols such as C.sub.2-C.sub.8 alcohols) in the feed stream. Accordingly, the present disclosure is uniquely suited to the production of fuels derived from bio-based alcohols, wherein olefins produced from such bio-based alcohols typically contain high levels of oxygenates.

In a process for hydrotreatment of a gas stream containing both olefins and diolefins as well as organic sulfur compounds, the gas stream is introduced into a pre-treatment reactor, where diolefins are reacted with hydrogen in the presence of a supported Mo-catalyst not containing Co or Ni, whereby the diolefins are substantially converted to olefins. Then the gas stream is introduced into a hydrotreater reactor having a higher inlet temperature than the pre-treatment reactor, in which the gas stream is reacted with hydrogen in the presence of a hydrotreating catalyst under hydrodesulfurisation process conditions, whereby the olefins are substantially converted to paraffins and the organic sulfur compounds are converted to H.sub.2S, which is removed by subjecting the hydrotreated gas to a chemisorption or physisorption treatment.