Processes for separating methane from a gas mixture that comprises methane and C.sub.2 gas, including C.sub.2+ gas, and other gases, including CO.sub.2 and H.sub.2S, that are based upon formation of gas hydrates, and systems useful for implementing such processes, are disclosed.

Processes for separating methane from a gas mixture that comprises methane and C.sub.2 gas, including C.sub.2+ gas, and other gases, including CO.sub.2 and H.sub.2S, that are based upon formation of gas hydrates, and systems useful for implementing such processes, are disclosed.

Processes for separating methane from a gas mixture that comprises methane and C.sub.2 gas, including C.sub.2+ gas, and other gases, including CO.sub.2 and H.sub.2S, that are based upon formation of gas hydrates, and systems useful for implementing such processes, are disclosed.

Provided is a method for preparing an oligomer including: supplying a monomer stream and a solvent stream to a reactor to perform an oligomerization reaction to prepare a reaction product; supplying a discharge stream from the reactor including the reaction product to a separation device and supplying a lower discharge stream from the separation device to a settling tank; adding an organic flocculant to the settling tank to settle and remove a polymer and supplying the lower discharge stream from the separation device from which the polymer is removed to a high boiling point separation column; and removing a high boiling point material from the lower portion in the high boiling point separation column and supplying an upper discharge stream including an oligomer to a solvent separation column.

Provided is a method for preparing an oligomer including: supplying a monomer stream and a solvent stream to a reactor to perform an oligomerization reaction to prepare a reaction product; supplying a discharge stream from the reactor including the reaction product to a separation device and supplying a lower discharge stream from the separation device to a settling tank; adding an organic flocculant to the settling tank to settle and remove a polymer and supplying the lower discharge stream from the separation device from which the polymer is removed to a high boiling point separation column; and removing a high boiling point material from the lower portion in the high boiling point separation column and supplying an upper discharge stream including an oligomer to a solvent separation column.

Methods, processes, systems, or apparatus are provided to remove contaminants such as metals and chlorine present in a pyrolysis stream to form reduced-contaminant liquid biomass. In certain embodiments, for example, a metal chelating agent is dissolved into a metal-containing pyrolysis stream condensate to form metal chelate complex, followed by filtering to obtain the reduced-contaminant liquid biomass.

Disclosed are methods and systems for removing a highly reactive polymer precursor such as carbonyls from a liquid hydrocarbon stream. Embodiments may disclose a method for removal of carbonyls from a liquid hydrocarbon stream comprising the steps of providing a liquid hydrocarbon stream containing carbonyls, providing a liquid bisulfite stream comprising an alkali metal bisulfite, and contacting the liquid hydrocarbon stream and the liquid bisulfite stream in a mass transfer device wherein at least a portion of the carbonyl reacts with the alkali metal bisulfite to form a solid adduct that is soluble in the bisulfite solution.

Disclosed are methods and systems for removing a highly reactive polymer precursor such as carbonyls from a liquid hydrocarbon stream. Embodiments may disclose a method for removal of carbonyls from a liquid hydrocarbon stream comprising the steps of providing a liquid hydrocarbon stream containing carbonyls, providing a liquid bisulfite stream comprising an alkali metal bisulfite, and contacting the liquid hydrocarbon stream and the liquid bisulfite stream in a mass transfer device wherein at least a portion of the carbonyl reacts with the alkali metal bisulfite to form a solid adduct that is soluble in the bisulfite solution.

Disclosed are methods and systems for removing a highly reactive polymer precursor such as carbonyls from a liquid hydrocarbon stream. Embodiments may disclose a method for removal of carbonyls from a liquid hydrocarbon stream comprising the steps of providing a liquid hydrocarbon stream containing carbonyls, providing a liquid bisulfite stream comprising an alkali metal bisulfite, and contacting the liquid hydrocarbon stream and the liquid bisulfite stream in a mass transfer device wherein at least a portion of the carbonyl reacts with the alkali metal bisulfite to form a solid adduct that is soluble in the bisulfite solution.

A method for separating an alkyl aromatic hydrocarbon, the method having a step of adding a first diluent and an extractant having a superacid to a mixture comprising the alkyl aromatic hydrocarbon and one or more isomers thereof to carry out an acid-base extraction to thereby form a complex of the alkyl aromatic hydrocarbon with the superacid, and thereafter separating the complex from the mixture, and a step of adding an eliminating agent having a relative basicity in a range of 0.06 to 10 with respect to the alkyl aromatic hydrocarbon and a second diluent to the complex, and carrying out complex exchange of the alkyl aromatic hydrocarbon for the eliminating agent to thereby separate the alkyl aromatic hydrocarbon from the complex.