Methods are provided for treatment of kerosene/jet fuel boiling range fractions, such as previously qualified jet fuel fractions, to allow blending of the kerosene/jet fuel boiling range fractions to produce a jet fuel boiling range blend having a breakpoint that is equal to or greater than the breakpoint of at least one of the kerosene jet fuel boiling range fractions used to form the blend. The breakpoint of the jet fuel boiling range blend can be maintained by treating at least one of the component fractions of the blend and/or by treating the blend to reduce a nitrogen content. The reduced nitrogen content can correspond to a reduced content of total nitrogen and/or a reduced content of unexpected nitrogen compounds.

A method of desulfurizing a liquid hydrocarbon having the steps of: adding a liquid hydrocarbon to a vessel, the hydrocarbon having a sulfur content; adding a catalyst and an oxidizer to create a mixture; oxidizing at least some of the sulfur content of the liquid hydrocarbon to form oxidized sulfur in the liquid hydrocarbon; separating the liquid hydrocarbon from the mixture; and removing at least some of the oxidized sulfur from the liquid hydrocarbon. Such methods can be carried out by batch or continuously. Systems for undertaking such methods are likewise disclosed.

At least one pH-sensitive component may contact a refinery stream for measuring the pH of the refinery stream. A light from a light source may be emitted onto the pH-sensitive component, and a detector may detect a first luminescence or color change of chromophore measurement radiated from the pH-sensitive component. A first pH of the refinery stream may be determined from the first luminescence or color change of chromophore measurement.

At least one pH-sensitive component may contact a refinery stream for measuring the pH of the refinery stream. A light from a light source may be emitted onto the pH-sensitive component, and a detector may detect a first luminescence or color change of chromophore measurement radiated from the pH-sensitive component. A first pH of the refinery stream may be determined from the first luminescence or color change of chromophore measurement.

A method comprises correlatingin a system which comprises a non-aqueous phase comprising a hydrocarbon fluid, and an aqueous phasepartitioning levels of a basic contaminant and/or an acid of interest into the aqueous phase with the pH of the aqueous phase. The partitioning levels of the basic contaminant and the acid of interest, as well as the pH of the aqueous phase, are obtained under conditions which are representative of those used in a partitioning process in which a basic contaminant is removed from a hydrocarbon fluid.

The correlations may be used in a method for selecting an acidic environment for use in a partitioning process, for estimating corrosion risk downstream of a partitioning process, or for controlling a partitioning process.

A method for producing an olefin polymer, in which an olefin compound is polymerized in the presence of a Lewis acid catalyst at a temperature of 0 C. or lower to obtain an olefin polymer, the method comprising a step of feeding a raw material liquid including the olefin compound to a reactor provided with a cooling unit, a step of polymerizing the olefin compound in the reactor to obtain a reaction liquid including the olefin polymer, a deactivation step of adding a deactivator to the reaction liquid taken out from the reactor to deactivate the Lewis acid catalyst, and a step of supplying the reaction liquid after the deactivation step to a cold recovery unit to recover cold from the reaction liquid, wherein the amount of the Lewis acid catalyst is 0.510.sup.3 to 1.010.sup.1 mol % based on the total amount of the olefin compound.

Systems and methods are provided for producing naphtha boiling range fractions having a reduced or minimized amount of sulfur and an increased and/or desirable octane rating and suitable for incorporation into a naphtha fuel product. A naphtha boiling range feed can be separated to form a lower boiling portion and a higher boiling portion. The lower boiling portion, containing a substantial amount of olefins, can be exposed to an acidic catalyst without the need for providing added hydrogen in the reaction environment. Additionally, during the exposure of the lower boiling portion to the acidic catalyst, a stream of light olefins (such as C.sub.2-C.sub.4 olefins) can be introduced into the reaction environment. Adding such light olefins can enhance the C.sub.5+ yield and/or improve the removal of sulfur from thiophene and methyl-thiophene compounds in the naphtha feed.