A process and system for separating butenes and butanes by extractive distillation using a polar solvent is disclosed. The process may include: contacting a hydrocarbon mixture including butanes and butenes with a lean solvent mixture in an extractive distillation column to form an enriched solvent fraction comprising butenes; recovering an overheads fraction comprising butanes and a bottoms fraction from the extractive distillation column; feeding the bottoms fraction to a stripper including a stripping section and a wash section; recovering the lean solvent mixture as a bottoms fraction and a stripper overheads fraction comprising butenes and water from the stripper; condensing the overheads fraction to form a water fraction and a product butenes fraction; feeding water as reflux to a top of the stripper wash section; feeding at least a portion of the condensed water fraction intermediate the top and bottom of the stripper wash section as a second reflux.

A process for supplying deaerated water to a chemical plant that includes a distillation column for separating a reaction effluent comprising water and a product. The process includes inventorying the distillation column with aerated water (water having an oxygen content of greater than 50 ppbw, such as greater than 1 ppmw). The aerated water in the distillation column may then be distilled to produce an oxygen-containing overheads and a bottoms fraction comprising deaerated water. The deaerated water in the bottoms fraction ma be transported to an upstream or a downstream unit operation, and utilizing the deaerated water in the upstream or downstream unit operation. The reaction effluent is fed to the distillation column, transitioning the distillation column from separating oxygen from water to operations for separating the product from the water.

A process for continuously removing water in situ from an oxidative esterification reaction includes (a) conducting a first oxidative esterification reaction in a first reactor or reaction zone, wherein the total number of reactors or reaction zones is n and n is at least 2; (b) removing a crude product stream from the first reactor or reaction zone; (c) introducing the crude product stream to a distillation column to generate a column overheads stream and a column bottoms stream; (d) passing at least a portion of the columns bottoms stream to the product recovery zone; and (e) passing at least a portion of the column overheads stream to a subsequent reactor or reaction zone; and (f) repeating steps (a)-(e) for each subsequent reactor or reaction zone such that the number of distillation columns less than n, and wherein the at least a portion of the column overheads stream contains less than 1 weight percent (wt %) water based on the total weight of the at least a portion of the column overheads stream.

A methanol/MMA azeotrope is broken or avoided by a method comprising the steps of (1) raising the pressure within a first vessel, e.g., a distillation column, that contains a methanol/MMA azeotrope, (2) collecting the azeotrope as a liquid, and then in a second, separate vessel, e.g., another distillation column, (3) raising the pressure sufficiently to allow for the breaking of or avoidance of the azeotrope and the recovery of the methanol.

Processes for the treatment of waste streams from the hydroconversion of heavy hydrocarbons containing additives and catalysts are described. At least one of the SHC pitch stream, SDA pitch stream, and the heavy residue stream is sent to a thermal oxidation system. The metals in the SHC and SDA pitch streams and the heavy residue stream are oxidized and can be easily recovered as clean powdered metal oxides which can be reused or sold. The processes produce chemicals which can be recovered and sold.

A process for treating effluent streams in a naphtha complex is described. One or more of the sour water stripping unit for the NHT sour water from the NHT, the amine treatment unit and the caustic treatment unit for the NHT stripper off-gas, the caustic scrubber unit or other chloride treatment unit for the off-gas from the C.sub.5-C.sub.6 isomerization zone and the C.sub.4 isomerization zone, and the caustic scrubber unit or other chloride treatment unit for the regenerator off-gas are replaced with a thermal oxidation system.

An improved process for the manufacture of technical grade (meth)acrylic acid, e.g., acrylic acid, the process comprising producing a hydrated reaction product from the gas-phase oxidation of at least one (meth)acrylic acid precursor, e.g., propylene, followed by first dehydrating and then concentrating the reaction product, the improvement comprising controlling at least one of the water, acetic acid and (meth)acrylic acid content of the reaction product during the purification of the reaction product using on-line, near IR spectroscopy.

Distillative process for obtaining ditrimethylolpropane from solutions includes separating ditrimethylolpropane from the solution in a first distillation unit into a first tops fraction comprising low-boiling compounds having a lower boiling point than ditrimethylolpropane and a first bottoms fraction; introducing the first bottoms fraction into a second distillation unit having at least 5 theoretical plates, said unit being configured as a thin-film evaporator with a column attachment and drawing off a second tops fraction comprising intermediate-boiling compounds having a lower boiling point than ditrimethylolpropane as well as withdrawing a second bottoms fraction from the second distillation unit and introducing the second bottoms fraction into a third distillation unit having at least 4 theoretical plates, said unit being configured as a thin-film evaporator with a column attachment, such that ditrimethylolpropane is obtained as a third tops fraction and high boilers are removed as a third bottoms fraction.

A process for recovering 1,3-butadiene from a C.sub.4 fraction, where the butadiene extraction processes may be operated at an intermediate pressure using a liquid ring type compressor. The use of a liquid ring compressor, among other process options presented herein, may advantageously reduce capital and operating costs, similar to the compressorless option, while mitigating the risks associated with the higher operating temperatures and pressures associated with the compressorless option. Thus, the embodiments of the processes disclosed herein encompass the best features of the conventional design (low pressure, with a compressor) with the advantages of the compressorless design (low capital and operating cost), as well as other advantages unique to the systems disclosed herein.

The present invention describes a process for obtaining para-xylene from a feedstock containing xylenes, ethylbenzene and C9+ hydrocarbons, said process comprising a single stage A of separation in a simulated moving bed carried out with a zeolite as adsorbent and a desorbent and making it possible to obtain at least three fractions, a fraction A1 comprising a mixture of para-xylene and of desorbent and two fractions A21, A22 comprising ethylbenzene (EB), ortho-xylene (OX) and meta-xylene (MX) and desorbent, said stage is carried out at a temperature between 20° C. and 250° C., under a pressure between the bubble pressure of the xylenes at the operating temperature and 2.0 MPa, and with a ratio by volume of the desorbent to the feedstock in the unit for separation 2 in a simulated moving bed is between 0.4 and 2.5, a stage B of fractionation by distillation in a 2-cut distillation column of the fractions A21 and A22 resulting from stage A, in which said fractions are introduced separately at distinct injection points, and makes it possible to obtain a fraction B2 containing ethylbenzene, ortho-xylene and meta-xylene, and a fraction B42 devoid of aromatic compounds having 8 carbon atoms and containing desorbent.