Abstract: Normal butane withdrawn from the main fractionator in an acid alkylation process is recycled to the main fractionator as required to insure that the actual alkylate to normal butane ratio in the alkylate product withdrawn from the main fractionator does not go below a desired ratio. Maintenance of the actual ratio at or above the desired ratio substantially minimizes the concentration of isobutane in the alkylate product stream.

Abstract: The present invention makes use of spent or loaded process liquid at relatively high pressure to power a pump for recirculation of regenerated process liquid for gas contact in a relatively high pressure gas-liquid contact apparatus. In this manner, the power fluid used for recirculation supplies about 65% of the pumping energy requirements and the remaining 35% of the needed pumping energy is supplied by an externally powered pump, such as an electric motor-driven or engine powered pump. In accordance with the present invention, the power end of the fluid-power pump is flooded with liquid at all times so that no free gas is used. The extra volume of liquid used for pumping is regenerated and pumped back to the contactor by an externally powered pump, for example, a plunger-type, electrically-driven or engine-driven pump.

Abstract: A method for working up residues of an extractive distilling process for obtaining pure hydrocarbons. The residue from an extractive distilling column is fed to the about middle part of a distilling column. The hydrocarbons are distilled and removed at the head of the distilling column and the solvent is removed at the bottom of the distilling column. A sidestream is removed from the distilling column at a position above the feed plate for the residue from the extractive distilling column via a so-called reflux evaporator plate having an elevated level of liquid. The sidestream is heated by indirect heat exchange with the solvent flowing from the distilling column. The heated-up sidestream is fed back into the distilling column at a level at or above the reflux evaporator plate. The concentration of the solvent at the reflux evaporator plate is controlled by the amount of reflux at the head of the distilling column.

Abstract: Butenes are added to the methanol-containing methyl-tertiary-butyl ether (MTBE) reactor effluent fractionation to effect recovery of substantially methanol-free MTBE bottoms product. Methanol analysis taken below the fractionator feed locus manipulates control of butenes addition. In an embodiment, the methanol-butenes-containing overhead stream from the fractionation is treated over activated alumina to adsorb methanol, yielding a methanol-free butenes feed for HF alkylation of isobutane. The used adsorbent can be regenerated using hot butenes product and/or MTBE reactor feed vapor with the recovered methanol being recycled to the MTBE reaction.

Abstract: A level-controlled water tank in an extractive distillation system is used to maintain the water concentration in the solvent mixture constant.

Abstract: In a fractional distillation column in which at least a first component and a second component are at least partially separated with the first component being removed principally as an overhead product and the second component being removed principally as a bottoms product and in which the heat supplied to the fractional distillation column is used as the primary control for the overhead product composition with the flow rate of external reflux to the fractional distillation column being used to control the bottoms product composition, a comparison of the actual concentration of the second component in the overhead product to the desired concentration is utilized to bias the control signal which is utilized to manipulate the flow rate of the external reflux to the fractional distillation column.

Abstract: In a fractional distillation column, a desired ratio between the flow rate of a side draw product stream and the internal reflux flow rate at the particular tray from which a side draw stream is withdrawn from the fractional distillation column is maintained by manipulating the flow rate of the center reflux stream so as to maintain the desired ratio between the internal reflux flow rate and a side draw product stream flow rate at the particular tray from which the side draw stream is withdrawn from the fractional distillation column. Control of the ratio between the flow rate of a side draw product stream and the internal reflux flow rate results in an improved side draw product stream purity.

Abstract: Control of multiple distillation columns for producing anhydrous alcohol suitable for blending with gasoline to produce gasohol. The distillation process involves production of a first-stage distillate containing a predetermined amount of water, followed by azeotropic distillation in the presence of a hydrocarbon entrainer to strip the distillate of its water content, leaving anhydrous alcohol as a bottom product. Tight controls are present during first-stage distillate production to hold its proof at an optimum value derived at through material balance calculations to minimize energy consumption for the overall system. Control over the dehydrating stage is accomplished by a combination of ratio control to regulate and maintain the proper proportion of the entrainer and temperature control to regulate within the column the actual inventory of entrainer.

Abstract: A control system for distillation column with a sidedraw line is provided wherein a prediction on the influence by changes in the feed stream with respect to the sidedraw composition is made.

Abstract: A liquid containing a solvent to be evaporated is fed to a concentration chamber which is fluidly connected to an evaporation chamber maintained at a reduced pressure. A vapor compression means withdraws solvent vapor from the evaporation chamber, compresses the vapor and forces the compressed vapor to a liquification chamber. Regulator means responsive to the density of the liquid remaining within the concentration chamber will regulate the rate of solvent evaporation to provide a concentrate suitable for recycling.A method of operating the still of this invention utilizes the technique of increasing the compressor capacity until the compressor begins to surge and then reducing the capacity a fixed amount to provide the desired efficiency.

Abstract: A batch distillation operation is automatically controlled from a start-up mode to a shut-down mode.

Abstract: A draw rate signal generator for an atmospheric crude distillation unit receiving crude oil and providing streams 1 through 5 and a reduced crude oil includes flow rate sensors sensing the flow rates of the crude oil and of streams 1 through 4 and providing corresponding signals. Analyzers sample the crude oil and provide signals corresponding to the 35% point temperature, the API gravity and the vapor pressure of the crude oil. End point analyzers sample streams Nos. 1 and 3 and provide signals representative of the end point temperatures of streams Nos. 1 and 3, respectively. 50% point analyzers sample streams 2, 3 and 4 and provide signals corresponding to the 50% point temperatures of streams Nos. 2, 3 and 4, respectively. A circuit connected to the sensors, to the crude analyzers, to the end point analyzers and to the 50% analyzers provide signals corresponding to the draw rates for streams Nos. 1 through 5 in accordance with signals from the sensors and analyzers.

Abstract: A vapor compression distiller having a shell for enclosing a pair of heat exchange tube bundles each having one end connected to a steam chest and its other end connected to a condensate collecting chamber. A vapor compressor has its inlet connected to the shell and the outlet to one steam chest which is coupled to a second steam chest through a steam ejector for elevating the inlet pressure to the second heat exchange tube bundle. A half partition extends across the lower end of the vessel and between the wells to divide the lower portion of the vessel into two sections which are in communication across the upper end of the vessel. One well is connected to receive fresh feed liquid and the other includes a density sensor to discharge a portion of the concentrate to therein maintain a desired concentrate level and each well is connected to a spray nozzle manifold disposed in its respective shell section.

Abstract: A control system for a multiple feed fractional distillation column is disclosed in which the flow rate signals of the multiple feed streams are delayed and combined for use in feedforward predictive control of the upper reflux flow, intermediate reflux flow and/or reboiler fluid flow to the fractional distillation column. Temperature measurements of the upper vapor stream, the upper reflux stream, the intermediate vapor stream and the intermediate reflux stream as well as analysis of a product stream can be utilized to provide feedback control of the fractional distillation column.

Abstract: Phenol containing less than 30 ppm hydroxyacetone is produced by feeding hydroxyacetone-contaminated phenol obtained by the decomposition of cumene hydroperoxide, which phenol is substantially free from cleavage catalyst and light ends such as acetone and water, and up to 22% by weight of cumene and/or alpha-methyl styrene to an intermediate point in a distillation column from which there is removed overhead a fraction containing cumene and/or alpha-methyl styrene and a substantial proportion of the hydroxyacetone in the feed and there is removed from the base a fraction comprising phenol containing less than 30 ppm hydroxyacetone, whilst maintaining the column under such conditions of temperature and pressure that cumene and/or alpha-methyl styrene forms from 55 to 80% by weight of the composition on the uppermost 15 to 70% of the trays in the stripping section and phenol forms greater than 50% by weight of the composition on the bottommost 10 to 50% of the trays in the stripping section.

Abstract: An improvement in a process for removing residual vinyl chloride monomer from an aqueous dispersion of a synthetic polymer wherein the dispersion is subjected to boiling conditions while being maintained in a vessel having a vapor space above the liquid level of the dispersion. In the improved process, the content of vinyl chloride monomer in the dispersion is continuously monitored by a boiling point suppression technique.

Abstract: A fractionation column is provided with a feed inlet and three product outlets, with the product outlets including an overhead vapor outlet, a bottoms liquid outlet and a side draw outlet. A plurality of vertically spaced apart vapor-liquid contact trays are mounted in the column. A generally vertical partition is positioned within the column in a central region between an upper and a lower vapor-liquid contact tray and divides the central region into first and second chambers defined by the upper and lower trays, column shell and partition. The feed inlet opens into the first chamber while the side draw outlet opens into the second chamber. First control means is provided for controlling the various inputs and outputs of the column. Second control means is also provided for measuring various constituent portions of fluid mixtures within the column.

Abstract: Apparatus comprising a solar still and a wind powered generator. Sea water is preheated in a condenser and is supplied to the still where it is heated further either by solar radiation, or by a heated pipe containing brine, or both. The still supplies warm humid air and vapor to the condenser to provide a distilled water condensate, which condensate is supplemented by water collected from the sloping parts of the still roof. The brine in the heated pipe in the still is supplied from a brine pit which is heated by electrodes connected to the wind powered generator. The generator also charges batteries and supplies electrical power to brine pumps and to a ventilator in the still.

Abstract: A control system is provided for a fractional distillation column where at least a portion of the overhead vapor stream from the fractional distillation column is utilized in a refrigeration and heating system for a process with which the fractional distillation column is associated. The liquid level is an overhead accumulator associated with the fractional distillation column is maintained at a level sufficient to insure that a sufficient supply of the overhead vapor stream from the fractional distillation column is available to supply the refrigeration and heating needs of the process with which the fractional distillation column is associated.

Abstract: In order to prevent corrosion of the apparatus in extraction and extractive distillation processes where N-substituted morpholine is employed as the selective solvent an additive is added to the solvent which additive consists of (a) phosphoric acid, (b) a salt thereof, (c) a vanadium compound, (d) a molybdenum compound or (e) a mixture of two or more of these compounds, the addition being effected in an amount of about 0.005 to 0.02% by weight of the morpholine solvent.

Abstract: A method for separating a feedstock comprising hydrogen sulfide, methyl mercaptan, methanol, and water in which a sufficient amount of water is injected into the fractionating column above the feedstock inlet to water wash the organic phase, decanting water and methanol from a tray below the feedstock inlet so that the stream comprising hydrogen sulfide and a minimum of water can be removed overhead and a stream comprising methyl mercaptan and a minimum of water can be removed as bottoms.

Abstract: Method and apparatus are disclosed for the automatic adjustment of the fractionation column pressure in a fractionator system which employs total condensation of overhead vapor and a liquid full reflux accumulator to thus float the column pressure above minimum column pressure. The set point of a pressure controller, which manipulates the overhead product control valve to adjust column pressure, is automatically adjusted in response to a desired offset of condensate subcooling from the overhead bubble point temperature which is repeatedly automatically calculated in response to analysis of the overhead product composition and pressure. Appropriate limits and overrides are also disclosed to prevent sudden changes in column pressure which might upset system operation.

Abstract: Method and apparatus are disclosed for the automatic adjustment of the fractionation column pressure in a fractionator system which employs total condensation of overhead vapor and a liquid full reflux accumulator to thus float the column pressure above minimum column pressure. The set point of a condensder fan pitch controller, which manipulates the blade pitch of the condenser fan, is automatically adjusted in response to a desired offset of condensate subcooling from the overhead bubble point temperature which is repeatedly automatically calculated in response to analysis of the overhead product composition and pressure. The set point of a pressure controller, which manipulates the overhead product control valve to adjust column pressure, is automatically adjusted in response to a fan pitch signal from the condenser fan pitch controller and a desired fan pitch set point. Appropriate limits and overrides are also disclosed to prevent sudden changes in column pressure which might upset system operation.

Abstract: Treatment of liquid waste contaminated with volatile radioactive substances under both acid and alkaline conditions in a single unit consisting of a still with connecting superposed column of spaced bubble-cap type plates. The pH of the liquid in the still is different from the pH of liquid reflux in an intermediate group of plates in the column facilitating scrubbing out of the volatile radioactive substances. An intermediate loop for circulating liquid from the bottom plate of the intermediate group to the top plate of the intermediate group at controlled pH is provided for this purpose.

Abstract: Wood pulp is bleached with chlorine dioxide gas. The gas is obtained by feeding a chlorine dioxide solution to a stripper. Shredded or fluffed pulp is exposed to a controlled amount of chlorine dioxide gas for a time period sufficient to obtain the required pulp brightness. The amount of unused chlorine dioxide gas is continuously monitored. The controlled amount of chlorine dioxide gas fed to the bleaching system is automatically adjusted by controlling the amount of chlorine dioxide solution fed to the stripper in response to changes in the amount of unused chlorine doxide gas leaving the bleaching system. Unreacted gases are recycled back to the stripper in response to the concentration of chlorine dioxide gas conducted from the stripper to the reaction area.

Abstract: An electronic system for automatically controlling the operation of a desalination system, and particularly such systems utilizing waste heat from internal combustion engines. The automatic control system is responsive to physical parameters within the desalinator and is particularly useful during warm-up and cooling periods at the beginning and end of use of such a desalination system for minimizing wear on system components and for maximizing the operational life of the system.

Abstract: A vapor compression distiller having a shell for enclosing a generally horizontal heat exchange tube bundle having one end connected to a steam chest and its other end connected to a condensate collecting chamber. A vapor compressor has its inlet connected to the shell and the outlet to the steam chest. The shell includes a pair of spaced apart wells at its lower end which are interconnected by a pipe connected below the expected level of liquid in each well. A half partition extends across the lower end of the vessel and between the wells to divide the lower portion of the vessel into two sections which are in communication across the upper end of the vessel. One well is connected to receive fresh feed liquid and the other includes a density sensor to discharge a portion of the concentrate to therein maintain a desired concentrate level and each well is connected to a spray nozzle manifold disposed in its respective shell section.

Abstract: A control for the amount of a gaseous fluid absorbed in a liquid flowing through an absorption column comprises a gage in an outlet from the absorption column for the liquid having the gaseous fluid absorbed therein, an auxiliary absorption column of a substantially smaller capacity than that of the absorption column and receiving a comparatively small amount of the gaseous fluid in addition to the liquid, another gage in an outlet from the auxiliary absorption column for the liquid having the gaseous fluid absorbed therein, the gages measuring respective parameters which are a function of the amount of the gaseous fluid absorbed in the liquid in the respective outlets and producing output signals corresponding to the respective parameters, a comparator connected to the gages for receiving the output signals and comparing them to produce a control signal, and a flow control in the inlet for the gaseous fluid or the liquid of the absorption column, the flow control being connected to the comparator and control

Abstract: In a fractionation system in which pressure fluctuations within the fractionation vessel can result in alteration of the fractionator product composition, fractionation column pressure is monitored and converted to a temperature requirement signal representative of the temperature required within a preselected portion of the fractionation column in order to provide the desired product constituent distribution. The heat input to the fractionation column is controlled in response to the temperature requirement signal, corrected as necessary by actual analysis of the product. In a preferred embodiment, control of a demethanizer column in a cryogenic natural gas liquids separation process can be practiced advantageously.

Abstract: Overflash within a withdrawal zone of a complex fractionating column is monitored to provide a control characteristic related to the efficiency of the fractionation column, and associated processes linked to the column. To accurately monitor the overflash, notched weir means including an upright wall means, is positioned at the intersection of the withdrawal tray and the downcomers connecting the former with a lower, adjacent fractionating tray. Differential pressure measuring means is also provided with sensing means in the vicinity of the notched weir means. The differential pressure measuring means produces a signal characteristic of said overflash. A complex controller means, external of the column, generates correction operators in response to said signal. Respective control means regulate column feed and withdrawal streams in response to said correction operators and thus maintain a pre-selected material balance within the column.

Abstract: The reboiler temperature of a depropanizer tower is controlled as the function of the propane content of the feed to the depropanizer tower and of the gasoline provided by the tower in accordance with a control signal. The Reid Vapor Pressure of crude oil feeding a flash tower is determined from the propane content of the depropanizer feed while the Reid Vapor Pressure of the gasoline is determined from the gasoline propane content. A control unit includes a network which determines a change in the Reid Vapor Pressure as the quality of the feed crude oil to the flash tower changes. When the change in the Reid Vapor Pressure exceeds a predetermined limit, the network provides a feed forward signal corresponding to a desired temperature associated with the new Reid Vapor pressure. The feed forward desired temperature signal is determined in accordance with the equations hereinafter disclosed.

Abstract: A control system controls the flow rates of waxy oil and solvent entering a dewaxing unit so as to control the viscosity of a chilled slurry mix or waxy oil and solvent provided to a filter in the dewaxing unit. The dewaxing unit includes valves controlling the flow rates of the solvent and waxy oil being provided to the chiller. The filter provides a dewaxed oil and solvent mixture and wax. Using the equation hereinafter mentioned, the control apparatus utilizes the sensed refractive index of the solvent, the sensed viscosity of the waxy oil, the sensed flow rates of the solvent and the waxy oil, and the sensed filtering temperature of the chilled slurry mix to generate a signal corresponding to the viscosity of the slurry mix provided to the filter at the filtering temperature. The viscosity of the chilled slurry mix is controlled within predetermined limits by a generating signal corresponding to the dilution ratio of the solvent to the waxy oil.

Abstract: A scale removal method for use in saline water desalting apparatus characterized in that, during the time the desalting operation is being performed, an acid is added to the saline water for short periods at predetermined time intervals in the salt water passages for condensation, heating and heat recovery.