Processes are described for separating 3,4′- and 4,4′-dimethylbiphenyl from a mixture comprising at least 3,3′-, 3,4′- and 4,4′-dimethylbiphenyl. In the processes, the mixture is cooled to produce a crystallization product comprising at least of the 4,4′-dimethylbiphenyl from the feed mixture and a first mother liquor product. The first mother liquor product is distilled to produce a bottoms stream enriched in 4,4′-dimethylbiphenyl as compared with the first mother liquor product and an overhead stream deficient in 4,4′-dimethylbiphenyl as compared with the first mother liquor product. The overhead stream is then cooled to produce a second crystallization product comprising at least part of the 3,4′-dimethylbiphenyl from the overhead stream and a second mother liquor product.

Provided are a purification device and method. The purification device and method make most use of an internal heat source in the distillation column in the process of distilling the raw material, and reduce use of an external heat source. Thereby, the purification device and method can improve energy efficiency of all the processes.

The present subject matter relates to methods and apparatuses for the continuous preparation of a cumene feed for a cumene oxidation process. More specifically, the subject matter relates to a process for passing a cumene alpha-methylstyrene stream through a caustic wash column having an integrated water wash section for the removal of organic acids.

A method of determining sulfur content in an aqueous fluid containing spent hydrogen sulfide scavenger from a scrubber or contactor tower is described as is a method of optimizing the hydrogen sulfide scavenger treatment rate in a scrubber or contactor tower. The method includes the steps of providing a sample of an aqueous fluid from the scrubbing tower where the aqueous fluid contains spent hydrogen sulfide scavenger; and using x-ray fluorescence to determine the amount of total sulfur in the sample. The method may also use the total sulfur content in the sample to determine the spent hydrogen sulfide scavenger in the sample and/or determine scavenger uptake. The method may also include the step of adjusting the amount of scavenger introduced into the aqueous fluid in the tower in response to the scavenger uptake, to optimize the scavenger treatment in the scrubber or contactor tower.

Apparatus and process for converting aromatic compounds, comprising/using: a fractionating train (4-7) suitable for extracting at least one benzene-comprising fraction (22), one toluene-comprising fraction (23) and one fraction (24) comprising xylenes and ethylbenzene from the feedstock (2); a xylene separating unit (10) suitable for treating the fraction comprising xylenes and ethylbenzene and producing a para-xylene-comprising extract (39) and a raffinate (40) comprising ortho-xylene, meta-xylene and ethylbenzene; an isomerizing unit (11) for treating the raffinate and producing a para-xylene-enriched isomerizate (42), which is sent to the fractionating train; and an alkylating reaction section (13) for treating at least part of the benzene-comprising fraction with an ethylene source (30) and producing an alkylation effluent (31) comprising ethylbenzene, which is sent to the isomerizing unit.

A dividing wall column system for producing hexane includes a dividing wall column including a dividing wall that divides the dividing wall column at least partially into a first side and a second side, with one side of the first and second sides configured to operate as a deisohexanizer column and the other side of the first and second side configured to operate as a hexane column to produce hexane.

Improved systems and methods for producing propylene from olefins including isobutylene is disclosed. The improvements combine streams containing co-produced 1-butene, 2-butene, butadiene, and heavy olefins (C5+) exiting both a metathesis reactor and a skeletal isomerization reactor in a gasoline fractionation tower to remove the heavy olefins. The C4-containing distillate from the gasoline fractionation tower is then fed to a hydroisomerization unit to form mono-olefins and 2-butene. The resulting 2-butene rich stream can then be utilized in metathesis reactions to increase the production of propylene while increasing the lifetime of the metathesis catalyst.

A process (100, 200, 300) for the production of ethylene is proposed in which a first feed gas (A) and a second feed gas (B) are fed to a reactor (1) and processed therein by vapour cracking to obtain a product mixture (C), the first feed gas (A) comprising more than 90 weight percent saturated hydrocarbons and more than 80 weight percent ethane, and wherein the product mixture (C) or a part thereof is subjected to a treatment (2, 3, 4) and the resulting mixture (F) or a part thereof is subjected to a separation (10) to obtain a resulting mixture (F) containing hydrogen, methane, ethane, ethylene and hydrocarbons having three, four and at least five carbon atoms. The separation (10) being provided in that it comprises an ethylene separation step (7) to which at least the ethane, the ethylene and the hydrocarbons having three carbon atoms from the succeeding mixture (F) or a part thereof are fed unseparated from each other in a common separation insert (S, V, X), in which in the ethylene separation step (7) a light fraction (K) containing more than 95 mole percent ethylene is fed, and a heavy fraction (T, W, Y) containing at least a portion of the ethane from the separation insert (S, V, X) and at least 15% by weight of the hydrocarbons having three and four carbon atoms from the separation insert (S, V, X), and wherein the heavy separation product (T, W, Y) from the ethylene separation step (7) or a portion thereof is used as part or to form the second feed gas (B). A corresponding annex is also the subject of this invention.

A method and an apparatus for preparing an oligomer, the method including supplying a feed stream including a monomer to a reactor to perform an oligomerization reaction, recovering unreacted monomer, and dissolving the recovered unreacted monomer in a solvent in a monomer dissolution device and supplying a discharge stream from the monomer dissolution device to the reactor. The method and the apparatus provide reduced investment costs and improved economic feasibility as there is no need to use a refrigerant at a very low temperature or install a separate compressor to recover and reuse the unreacted monomer in an oligomer production process.

A method and an apparatus for preparing an oligomer, the method including supplying a feed stream including a monomer to a reactor to perform an oligomerization reaction, recovering unreacted monomer, and dissolving the recovered unreacted monomer in a solvent in a monomer dissolution device and supplying a discharge stream from the monomer dissolution device to the reactor. The method and the apparatus provide reduced investment costs and improved economic feasibility as there is no need to use a refrigerant at a very low temperature or install a separate compressor to recover and reuse the unreacted monomer in an oligomer production process.