The Dow Chemical Company

Lanny A Robbins

Timothy Charles Frank

George R Killat

Von G Landon

Thad S Hormel

Wayne C Muench

Pamela M Kirchhoff

Herbert A Johnson

Ben B Gammill

A method for recovering methanol from sulfur-based wood pulping process vapors, which contain at least methanol and dimethyl disulfide. The method involves three steps. The first step consists of introducing the vapors into a first distillation tower at a vapor introduction point. The second step consists of introducing water into the first tower at a point above the vapor introduction point. The third step consists of heating liquid which is in the first tower below the vapor introduction point so that a liquid stream flows from the bottom of the first tower and a gas stream flows from the top of the first tower. The liquid stream contains most of the methanol originally in the vapors. The gas stream contains most of the dimethyl disulfide originally in the vapors. The liquid stream can then be distilled in a second distillation tower by conventional distillation to produce dry methanol. The first and third steps can be combined by introducing sufficiently heated vapors. When the vapors contain more than sixty percent water, then there need be only two steps. The first step consists of introducing the vapors into a first distillation tower at a vapor introduction point. The second step consists of heating liquid which is in the first tower below the vapor introduction point so that a liquid stream flows from the bottom of the first tower and a gas stream flows from the top of the first tower.

Methanol recovery using extractive distillation

A process is provided for separating trace amounts of water-immiscible, volatile organic liquids dissolved in aqueous media whereby the aqueous media are subjected to vapor stripping under vacuum at about ambient temperature in conjunction with a heat pump which indirectly recovers the energy of vaporization in its cold loop and returns such energy to the vaporization of the aqueous media in its hot loop. Inasmuch as the entire process is conducted at ambient temperature, there is little loss of energy to the environment and processing energy is recovered and reused to the application of a heat pump system.

Method for removing dissolved immiscible organics from am aqueous medium

A process for the purification of an aromatic compound, e.g. isopropylidenediphenol, comprising using a multi-stage countercurrent process wherein the crystals are melted by the addition of heat and water prior to each crystallization step and wherein one crystallization is accomplished at a pre-selected low temperature.

Countercurrent multi-stage water crystallization of aromatic compounds

In a pressure swing adsorption system used to recover an oil-soluble solvent, monomer or hydrocarbon vapor such as 1,1,1-trichloroethane or styrene from a gaseous stream such as air, an oil-sealed vacuum pump may be used without substantial absorption of vapor into the oil if the oil in the pump is heated to a temperature substantially above the dew point of vapor in the gas stream leaving the pump.

Pressure swing adsorption apparatus and process for recovery of

The present invention provides a process for separating a condensable gas from a non-condensable gas by switching at least three adsorber beds which preferentially adsorb the condensable gas serially through the following steps:

Recovery process

An improvement in an apparatus for distributing a downflowing liquid uniformly across the packed bed of a vapor-liquid contact column is disclosed. The improvement comprises a predistributor which comprises a plate and an upstanding wall member along one edge. This wall member defines the periphery of the plate such that an open-top compartment is formed. A plurality of drip tubes is installed in the compartment and are defined by upstanding tubular members which extend above and below the plate and which are fastened to the plate, each drip tube having a lengthwise slot extending from the top of the drip tube. The apparatus also comprises a lower distributor unit, which can be of a conventional design or substantially similar to the upper distributor unit, except with additional wall members define separate, open-top compartments. The predistributor and lower distributor unit are mounted horizontally inside the column above the packed bed, such that the predistributor unit is oriented above the lower distributor unit, and at least one of the predistributor unit's drip tubes is in liquid connection with the lower unit. The downflowing liquid enters the predistributor unit through a standpipe conduit, flows through the drip tubes of the predistributor into the lower distributor, then continues through the lower distributor unit downwardly onto the packing.

Liquid distributor apparatus for high turndown ratios and minimum fouling

A distillation system and process for removing vaporizable components from an aqueous medium including a distillation column for receiving an aqueous medium containing vaporizable components and passing steam through the column such that the steam directly contacts the aqueous medium to vaporize at least a portion of the components, a condenser in a communication with the column to condense at least a portion of the vapor in the column, a separator in communication with the condenser to separate flash vapor from liquid condensate in the separator and a thermal compressor in communication with the separator and the column to remove vapor from the separator and to inject exhaust steam from the thermal compressor into the column.

Distillation system and process

A system and method is disclosed for removing dissolved organic impurities, such as gasoline or other hydrocarbons, from groundwater. The contaminated water is fed into a stripper column, operated under a deep vacuum, to enable the water to enter the column at its boiling point. Steam, as a vaporizing gas, strips the impurities out of the water and the overhead vapor phase is compressed to boost it to a higher pressure, so it can be condensed to vaporize part of the bottoms stream from the column. Since the bottoms stream is mostly water, the vapor generated is the steam used to strip impurities from the water.

System and method for removing volatile components from an aqueous medium

There is disclosed the process for the separation of the clay particles (ash) from coal particles by the use of two immiscible liquids followed by the separation and removal of the liquids from the solids.

Coal cleaning and the removal of ash from coal

An apparatus is disclosed for distributing a downflowing liquid uniformly across the packed bed of a vapor-liquid contact column. The apparatus consists of a distributor unit and a parting manifold. The distributor unit includes a plate with upstanding walls positioned crosswise and lengthwise on the plate to define separate, open-top compartments. Installed in each compartment are a number of drip tubes which extend above and below the plate. Gas riser openings are positioned between certain compartments and the distributor unit is mounted inside the column above the packed bed. The parting manifold is mounted above the distributor unit, and it includes a header circuit, crosswise end conduits, a crosswise lateral conduit, and a vertical standpipe conduit. The end conduits and lateral conduit have closed ends and each includes outlet ports therein. The downflowing liquid enters the manifold through the standpipe conduit, drops through the outlet ports into each compartment, and flows downwardly through the drip tubes onto the packing.

Liquid distributor apparatus for a vapor-liquid contact column

Organic material having a normal boiling point in excess of 200.degree. C. and a relative volatility with respect to water of at least one is removed from water contaminated therewith. The process comprises passing a current of vapor, sufficient to vaporize at least a portion of the organic material, through a moving stream of the contaminated water. In a preferred embodiment, the process comprises adjusting the pH of the contaminated water to a level sufficient to prevent substantial dissociation of the organic material. The contaminated water is then countercurrently contacted with a sufficient vapor flow to vaporize at least a portion of the organic material. The resulting organic material-containing vapor can be recovered, and the organic material removed. Illustrative of the process is the removal by air stripping of pentachlorophenol from waste water contaminated with about 250 parts per billion thereof.

Method of removing contaminants from water

A process is provided for the production of hydroxybenzyl alcohols, comprising condensing phenol with formaldehyde in an alkaline solution to form a mixture of ortho- and para-hydroxymethyl phenols, and solvent extracting unreacted phenol from the resulting alkaline hydroxybenzyl alcohol condensate solution. The phenol-reduced hydroxybenzyl alcohol condensate solution is particularly suited for treatment with excess caustic and subsequent oxidation of the resulting aqueous solution of ortho- and para-hydroxybenzyl alcohols-sodium salt to yield the corresponding ortho- and para-hydroxybenzaldehydes-sodium salt.

Process for the production of hydroxybenzyl alcohols

Disclosed is a sieve tray extraction column useful for performing liquid-liquid extractions. The sieve trays are made in the form of tubular members with an open top end and one or more openings in the bottom end and in the side of the member. Each tubular member is of smaller diameter than the column and is sealed to the inside of the column wall at the top end only. An annular space is thus defined between each tubular member and the inner column wall. In this structure the annular space functions as an upcomer or downcomer for passage of the solvent liquid through the column.

Growing community of inventors

Midland, MI, United States of America

Lanny A Robbins