Abstract: A method for regulating, or controlling heat input to the reboiler section of a fractionation column. Flow-measuring means, disposed in a substantially liquid-free environment within the confines of the reboiler section, produces a signal which is representative of the quantity of vapor flowing from the reboiler section upwardly into the fractionation section. This signal is transmitted to heat-varying means, whereby fuel input to an external reboiler heater is regulated in response to the quantity of vapor flow.

Abstract: A solvent extraction process for separating polar hydrocarbons from non-polar hydrocarbons. The solvent-rich extract phase is introduced into a stripping column, the bottoms from which, a polar hydrocarbon-containing, solvent-rich stream, is introduced into an upper portion of a solvent recovery column. A vaporous stripping medium is introduced into a lower portion of the solvent recovery column. Polar hydrocarbons in concentrated form are recovered as an overhead stream, a solvent-rich stream, virtually free from hydrocarbons, is withdrawn as a bottoms product and recycled to the extraction zone, while a hydrocarbon-containing side-cut solvent-rich phase is withdrawn and introduced into the stripping column with the extract phase.

Abstract: A process for simultaneously generating power and recovering potable water from a source of salinous water -- e.g. sea water. Salinous water, from a locus which is proximate to the surface thereof and at a relatively high temperature -- e.g. about 85.degree. F. -- is exposed to radiant solar energy to increase significantly the temperature thereof -- e.g. to a level of at least about 135.degree. F. The heated water is introduced into a plurality of flash separation zones, each succeeding one of which is maintained at a lower subatmospheric pressure than the preceding zone, to provide substantially non-salinous vapor phases. The salinous liquid phase is introduced in series through the plurality of flash zones. The vapor phases are passed through separate, individual turbines, or into different stages of a multiple-stage turbine, from the resulting motion of which power is generated.

Abstract: A process for the separation of a para-isomer from a hydrocarbon feed stock containing alkyl-aromatic hydrocarbons having more than eight carbon atoms per molecule which employs a crystalline aluminosilicate adsorbent containing a particular cation or cations to selectively adsorb either a para-, meta-, or ortho- isomer from the feed stock. A feed stock contacts an adsorbent which allows one or more isomers from the feed stock to be selectively adsorbed by the adsorbent. The selectively adsorbed component is thereafter recovered from the adsorbent in a more pure form as compared to the other isomers in the feed stock. The process can be performed in both the liquid or vapor phase.

Abstract: Water is removed from an alkaline solution used to extract relatively high concentrations of mercaptans from a hydrocarbon stream by stripping the alkaline solution with a hydrocarbon vapor stream. The vapor stream is then admixed with the oxygen-containing off-gas stream of the process to enrich the off-gas stream above its explosive limit.

Abstract: The reaction product effluent emanating from an isoparaffinic/olefinic, HF-alkylation reactor system, containing normal paraffins, motor fuel, alkylate, unreacted isoparaffins, hydrogen fluoride catalyst and organic fluoride compounds, is separated to recover a motor fuel alkylate product substantially free from fluoride compounds, and having a predetermined volatility, or vapor pressure. Two separation zones are employed to produce an alkylate containing hydrogen fluoride and a normal paraffin stream containing organic fluoride and hydrogen fluoride. Three treating zones afford the recovery of a fluoride-free motor fuel alkylate and a fluoride-free normal paraffin concentrate; a portion of the latter is blended with the former to adjust the volatility to the predetermined level.

Abstract: A process for the dehydrogenation of alkylaromatic hydrocarbons, such as ethylbenzene, in which a water stream formed by condensing and separating the effluent of the reaction zone is treated for the removal of alkenylaromatic hydrocarbons by passage through a liquid-liquid extraction zone, and the alkenylaromatic hydrocarbons are then recovered by admixing the extract stream with the effluent as part of the cooling performed before the effluent is passed into a liquid phase separation zone.

Abstract: High efficiency in extraction operations, such as extracting mercaptans from hydrocarbons with caustic, is obtained over a wide range of flow rates through a single extraction column by the provision of an intermediate product drawoff means located between a downstream section of extraction trays having greatest efficiency at low throughputs and an upstream section of trays having peak efficiency at high throughputs. A second product stream is removed after passing through the low flow rate trays and is blended with the stream from the intermediate drawoff means.

Abstract: A process for the production of paraxylene by the catalytic isomerization of xylenes wherein the reaction zone effluent is fractionated in three columns in series with the overhead product of the second column in the series being sent to a paraxylene separation zone, C.sub.9 hydrocarbons being rejected as the bottoms product of the third column, and the overhead product of the third column being combined with the raffinate stream of the paraxylene separation zone and recycled to the isomerization zone.

Abstract: A pressure control system and method for utilization in a process for effecting the alkylation of an aromatic hydrocarbon with a normally gaseous olefinic feed stream. The system is intended to control the pressure within a fractional distillation column which initially recovers the alkylaromatic product from unreacted aromatic hydrocarbons and a minor quantity of normally gaseous paraffinic contaminants contained in the olefinic feed stream. The system is especially advantageous in the boron trifluoride-catalyzed alkylation of benzene with ethylene, the latter containing minor quantities of ethane which must necessarily be vented, or removed from the system.

Abstract: Heat balance of a fractionation column is controlled and maintained by obtaining three differential temperatures between selected temperature-sensing points along the height of the column. A signal representing one of the delta-T's is employed in regulating the quantity of reflux returned to the rectification zone. The remaining two delta-T's are conjunctively utilized to regulate the enthalpy (heat-input content) of the reboiled liquid bottoms stream being returned to the reboiler section of the column. With respect to the latter, a selected one of the two delta-T signals is multiplied by a multiplier representing the ratio of the number of trays between the temperature sensing points supplying the non-selected delta-T signal to the number of trays between the temperature sensing points supplying the selected delta-T signal.

Abstract: Contaminants, such as water and hydrogen sulfide, are removed from hydrocarbon streams by the use of beds of solid adsorbents including molecular sieves. The adsorbents are regenerated by heating, with the heating being performed in a closed-loop operation wherein a small quantity of the hydrocarbon being treated is recycled in a closed-loop recirculation system comprising the adsorbent and a heater until the adsorbent reaches an effective regeneration temperature. Closed-loop operation is then terminated, and a regeneration gas is passed into the system and the adsorbent on a once-through basis.

Abstract: The efficiency of a fractionation column is increased by the provision of vertical baffles which descend from the lower surface of an upper fractionation tray to a point above the liquid maintained on the next lower fractionation tray and which are oriented perpendicular to the liquid flow across the fractionation tray to thereby segregate the vapors passing through the different portions of the fractionation tray segmented by the baffles.

Abstract: Heat balance of a fractionation column is controlled and maintained by obtaining three differential temperatures between selected temperature-sensing points along the height of the column. Signals representing the three delta-T's are employed in regulating the quantity of reflux to the rectification zone and the enthalpy (heat-input content) of the reboiled liquid bottoms stream. With respect to the latter, two delta-T's, obtained below the feed locus are used. One of these is considered in conjunction with the third delta-T, obtained above the feed tray, and an additional signal representing the flow rate of the feed stream, to regulate the quantity of reflux.

Abstract: Control of a fractionation column is maintained by obtaining two differential temperatures between pairs of selected temperature-sensing points along the height of the column. One pair of temperature sensors is vertically-spaced above the feed tray, while the second pair is below the feed tray. Signals representing the sensed and measured delta-T's are employed in conjunction with a signal representing the flow rate of the feed stream in regulating the quantity of reflux to the rectification zone and in maintaining the required reflux to feed ratio.

Abstract: A hydrocarbon stream comprising benzene is stripped at a high temperature to allow passage of the stripper bottoms stream into a clay treating zone without further heating, and the effluent of the clay treating zone is then exchanged against the feed stream to the stripper column to recover heat. Operation at the optimum clay treating temperature is achieved by adjusting the amount of the stripper bottoms stream which is split off for cooling by heat exchange against the feed to the stripper column. The cooled split-off portion is then admixed with the remaining high temperature portion.

Abstract: Heat balance of a fractionation column is maintained through the utilization of differential temperature sensors located at selected points in the height of the column. Signals representative of three delta-T's are employed in regulating the quantity of reflux to the rectification zone and the enthalpy (heat-input content) of the reboiled liquid bottoms stream. With respect to the former, two differential-temperature signals are used; these result from four temperature sensors vertically-spaced along virtually the entire height of the fractionation column.

Abstract: A control method and system for regulating the heat input to the reboiler section of a distillation column having attendant thereto a first external heat-recovery reboiler. Flow-measuring means, disposed within a substantially liquid-free environment, produces a signal which is representative of the quantity of vapor flowing from the reboiler section upwardly into the fractionation section of the column. This signal is transmitted to heat-varying means whereby the heat input to a second external reboiler heater is regulated in response to the quantity of vapor flow.

Abstract: A process for the fractionation of hydrocarbons which includes the steps of extracting heat from a liquid sidecut stream, splitting the sidecut stream into two portions, splitting the liquid stream formed by condensing the overhead vapor stream into two portions, admixing one of the portions of the sidecut stream with one of the portions of the overhead liquid stream to form the reflux to the fractionation column, and admixing the other portion of each stream to form a product stream.

Abstract: A reactor for use with liquid phase reactants which separate into two liquid phases comprising a vertical vessel divided into an upper particle contacting-liquid retention chamber and a lower phase separation chamber by a horizontal liquid barrier. The two phases which form in the upper chamber are separately transferred to an appropriate level in the lower chamber through separate conduits to avoid remixing.