Provided is a method capable of yielding high-purity 1,3-butylene glycol having a very low content of a high boiling point component and a low dry point, with a high recovery ratio. A method for producing 1,3-butylene glycol to yield purified 1,3-butylene glycol from a reaction crude liquid containing 1,3-butylene glycol, in which, in a high boiling point component removal column for use in the removing a high boiling point component, a charged liquid containing 1,3 -butylene glycol is distilled under conditions that (i) a reflux ratio is greater than 0.02 in a case where a concentration of 1,3-butylene glycol in the charged liquid is 95% or less, or a reflux ratio is greater than 0.01 in a case where the concentration of 1,3-butylene glycol in the charged liquid is greater than 95%, and (ii) a bottom ratio of less than 30 wt. %, high-purity 1,3-butylene glycol is distilled off from above a charging plate, and a liquid in which a high boiling point component is concentrated is extracted from below the charging plate.

The invention relates to a process for producing ethylene carbonate and/or ethylene glycol, which comprises the following steps: a) supplying an overhead absorber stream withdrawn from an absorber to a vapor-liquid separator to yield an aqueous bottoms stream and a recycle gas stream; b) supplying an aqueous process stream comprising one or more impurities to a distillation apparatus to yield an overhead impurities stream and a purified aqueous process stream, wherein the aqueous process stream supplied to the distillation apparatus comprises at least a portion of the aqueous bottoms stream withdrawn from the vapor-liquid separator, wherein the overhead impurities stream is supplied to a condenser and is cooled to a temperature in the range of from 5 to 95° C., wherein the cooled overhead impurities stream is split into a reflux stream which is recycled to the distillation apparatus and an overhead impurities stream; and further steps c) and d).

The present invention relates to a process for treating, by reactive distillation, an olefinic feedstock comprising linear olefins containing n carbon atoms, and branched olefins, the branched olefins comprising tertiary branched olefins, for example a mixture of n-butenes and of tertiary branched olefins comprising isobutene, so as to produce an olefinic effluent with a mass content of tertiary branched olefin of less than or equal to 3% by weight and a heavy hydrocarbon effluent, said process comprising the feeding of a reactive distillation section with said olefinic feedstock and with an alcohol feedstock comprising a primary alcohol, said reactive distillation section comprising a column composed at least of an upper reflux zone into which is introduced said alcohol feedstock, comprising, for example, ethanol, an intermediate reaction zone comprising at least 6 reactive doublets, and a lower fractionation zone at the level of which said section is fed with said olefinic feedstock, said reactive distillation section being operated at a relative pressure of between 0.3 and 0.5 MPa, a column head temperature of between 40° C. and 60° C., with a reflux ratio of between 1.8 and 2.2.

Provided is a method of separating and purifying a mixture of components having small difference in boiling point, and the method may maximize an energy collecting amount and collect a product to be desired in high purity and high yield.

The subject process enhances catalytic activity for demetallization and desulfurization of a residue feed stream by splitting a recycle hydrogen stream and feeding each of the split hydrogen streams to the first and second stages of demetallation and desulfurization, respectively, with interstage separation. The recycle hydrogen stream may first undergo scrubbing to remove acid gases and compression before recycle. The recycle hydrogen stream is taken from a first hot vapor stream from the first hydrotreating unit and a second hot vapor stream from the second hydrotreating unit.

A method of column control includes: passing a feed stream and a make-up stream through a column; withdrawing an overhead fraction from the column; purging at least a portion of the overhead fraction; cooling at least a portion of the overhead fraction in a heat exchanger and passing it through a reflux drum; withdrawing a purge stream and a distillate stream from the reflux drum, wherein the distillate stream has a constant flow rate; recycling at least a portion of the distillate stream back to the column; and passing at least a portion of the distillate stream to a downstream process.

The present application relates to a selective distillation apparatus and a distillation method, which provides a distillation apparatus capable of switching between a serial connection mode and a parallel connection mode on the situation, thereby enabling selective operation of high-efficiency operation and high-capacity operation.

Method and apparatus are provided for efficient metal distillation, and for related primary product process. Vertically stacked and gravity-driven evaporators and condensers are employed to distill metals, such metals having different volatilities. A multiple-effect thermal system of magnesium and other volatile metals is used to efficiently distill and separate metals from multiple metal alloys.

Systems and methods are provided for improving process control of separation systems that include one or more dividing walls within a single column. It has been discovered that improved process control can be achieved by controlling the dividing wall columns based on energy balance instead of mass balance. The energy balancing can be performed in part based on controlling temperature at a plurality of locations on the feed side within a first divided portion of the column. Using energy balancing based on temperature control at a plurality of locations on the feed side can facilitate maintaining the operation of the dividing wall columns within a single region of phase space that can be suitably approximated by linear models. This can allow conventional process controllers to manage the manipulated and controlled variables. In addition to controlling the temperature at a plurality of locations on the feed side, a plurality of other characteristics can be used as manipulated or controlled variables. Optionally, a multivariable controller can be used to provide further improved control of the column.

A method of obtaining purified DMF from a mixture comprising DMF and hydrogen chloride (HCl) involving distillation is provided.