Abstract: In the recovery of natural gas liquids by partial condensation, flashing, and compression, minimum and maximum temperature control of partially condensed feed stream hydrocarbons to a product separator is imposed by a minimum temperature control system which provides the same set point to the pressure controllers on the compressor suction scrubbers for both the product and the flashed vapor produced from the liquid outlet of the product separator with one of the two output signals responsive to the pressure of the product suction scrubber or the flashed vapor suction scrubber manipulating, by way of a selective relay, the engine speed controller of the dual compressor unit taking suction from the two scrubbers; and a maximum temperature controller which controls the rate of by-pass of natural gas feed around the partial condensation-separation system unless, by means of a selective relay, compressor availability is a more limiting criterion.

Abstract: The flow rate of feed material containing a constituent to be absorbed and the flow rate of the absorption medium entering an absorption zone are controlled in response to the content and flow rate of feed material entering the absorption zone and the amount of a desired bottoms constituent in the overhead stream of the absorption zone so that the efficiency of the absorption process is optimized. Under circumstances necessitating maximum production from the absorption zone and its associated stripping zone, the absorption medium flow rate is maintained at a maximum value and the feed flow rate is controlled in response to feed composition and flow as well as the concentration of desired bottom product in the overhead stream. The output of the absorption unit is stabilized by alteration of the flow control apparatus associated with the output stream of the stripping zone in order to alter the amount of control over the output flow.

Abstract: The flow rate of the absorption medium entering an absorption column and the flow rate of steam into a reboiler associated with a stripping column are controlled in response to the flow rate of a feed stream into the absorption column, the concentration of impurities in the feed stream, and the flow rate of the absorption medium containing the impurity removed from the feedstream into the stripping column in such a manner that the efficiency of the absorption process is optimized. A computer system is utilized to simulate the flow of materials inside the absorption and stripping columns. Feed forward control, based on the simulations, is utilized to maximize the energy efficiency of the absorption/stripping process by reducing the amount of steam required by the stripping process and reducing the energy consumption of the pumping system utilized to return the absorption medium to the absorption column.

Abstract: An oil treatment system for reclaiming used oil including apparatus for feeding the oil first through a filter for removing solid contaminants therefrom then through a vaporizer unit wherein it is heated under a vacuum while in a flowing film form to remove water, dissolved gases and volatile contaminants therefrom, and automatic control devices whereby treated oil cannot be discharged until it has been subjected to heat and vacuum in the necessary degrees, and whereby the system, once initiated by a starting or stopping signal, is automated to initiate or terminate operation of the various components of the system in a sequence operable to produce efficient, trouble-free operation of the system as a whole.

Abstract: A method for controlling pitch still operations is disclosed comprising measuring the temperature of a sample of pitch from the still at a preselected viscosity value, comparing the measured temperature with a predetermined temperature value, and adjusting the parameters of the still operation in response to the comparison. An apparatus for carrying out the method is also disclosed comprising a means for withdrawing and returning a sample of pitch from the reactor, a chamber for holding the sample of pitch, the chamber having a means for heating and cooling the sample, a temperature sensing device and a viscosity measuring device located in the chamber, and a means for recording the temperature value when the viscosity has reached a predetermined value.

Abstract: A method for controlling the production of pitch and the like is disclosed comprising simultaneously measuring the viscosity and temperature of the pitch material from the production unit, comparing the measured value with a predetermined correlation of the viscosity and temperature for the pitch, and adjusting the parameters of the production operation in response to the comparison. An apparatus for carrying out the method is also disclosed comprising a means for withdrawing and returning a sample of the pitch material from the still, a chamber for holding the sample of the pitch material, the chamber having a means for heating and cooling the sample, a temperature sensing device and a viscosity measuring device located in the chamber, and a means for recording the temperature and viscosity values.

Abstract: A method for controlling the production of pitch and the like is disclosed comprising simultaneously measuring the viscosity and temperature of the pitch material from the production unit, comparing the measured value with a predetermined correlation of the viscosity and temperature for the pitch, and adjusting the parameters of the production operation in response to the comparison. An apparatus for carrying out the method is also disclosed comprising a means for withdrawing and returning a sample of the pitch material from the still, a chamber for holding the sample of the pitch material, the chamber having a means for heating and cooling the sample, a temperature sensing device and a viscosity measuring device located in the chamber, and a means for recording the temperature and viscosity values.

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: In the recovery of natural gas liquids by partial condensation, flashing, and compression, minimum and maximum temperature control of partially condensed feed stream hydrocarbons to a product separator is imposed by a minimum temperature control system which provides the same set point to the pressure controllers on the compressor suction scrubbers for both the product and the flashed vapor produced from the liquid outlet of the product separator with one of the two output signals responsive to the pressure of the product suction scrubber or the flashed vapor suction scrubber manipulating, by way of a selective relay, the engine speed controller of the dual compressor unit taking suction from the two scrubbers; and a maximum temperature controller which controls the rate of by-pass of natural gas feed around the partial condensation-separation system unless, by means of a selective relay, compressor availability is a more limiting criterion.

Abstract: A method and apparatus for controlling the operation of a distillation column which utilizes cost factors to achieve the best economical production of a product within acceptable purity limits while maintaining the column at maximum operating capacity. The control is based on a series of priorities in which each of the following control signals is selectively used in turn to modify the control the heat-input to the column; cost factors applying to the column, cost factors applying to the several columns in the system, the purity of the product, the operating pressure limit of the column and, for lighter products, the rate of fluid velocity through the column. For heavier products, the rate of fluid velocity through the column is used independently of the heat-input control to restrict the flow of overhead product to the condenser to increase the back pressure on the column.

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 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: The method consists in preparing from the crude petroleum being processed a representative cut constituting a vaporized fraction having a known yield, in plotting the TBP curve of the cut by chromatographic analysis and by integration of the quantitative signal produced as a result of the analysis. The information obtained from the analysis is processed in order to operate a control unit for generating signals which serve to adjust the rates of withdrawal of the cuts at different predetermined levels of the column.

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: Adjustment and control of a product fraction stream and especially gas oil are effected by a control unit after processing information supplied by an analyzer which takes a direct measurement of the temperature of filtrability of the stream and by detectors which deliver signals representing the flow rate of the gas oil withdrawn, the rate of withdrawn of the next higher product stream, the flow rate of the crude petroleum being processed, the flow rate of the stripping vapor and of the next lower product stream, and the slope of the distillation curve of the crude petroleum in the gas oil zone.

Abstract: A sampling circuit connected directly to the distillation column consists of a primary loop formed by a sampling tube which penetrates into the column in a region of expansion and vaporization and is equipped with means for limiting the velocity of the vapor collected therein and for separating the entrained liquid fraction if necessary. The sampling circuit further comprises a condenser and a filter, the condensate being returned to the column by a circulating pump and a withdrawal of condensate being effected by a secondary loop for supplying an analyzing device in parallel.

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: A heat exchange method and flow control system for a hydrocarbon conversion process having two reactors in series which allows efficient heat recovery and effective process control under widely varying process conditions. The hydrocarbon feed stream is divided into three streams. In the preferred embodiment, the first stream is not heat exchanged and is controlled along with the preheater heat supply by a split range controller activated in response to the temperature of the stream entering the first reactor. The second stream is heat exchanged with the effluent of the first reactor and flows at a rate controlled by its temperature after this heat exchange. The third stream is heat exchanged with the effluent of the second reactor and flows at a rate such that the total of all three streams is the desired capacity for the unit. A hydrogen recycle stream is proportionally divided between the second and third streams by a ratio control means.

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: In a deodorizing apparatus, at least the lower part of a column is surrounded at least partly by compartments which are not connected together, each compartment having means for supplying treatment fluid and means for discharging the treated material with separate control but opening into a common duct. The duct for discharging the treated material from the central column is divided into separate ducts the outlets of which open into the compartments and which are provided with separately-controlled means for carrying the material to the respective compartments.

Abstract: The temperature of light straight run gasoline from a depropanizer tower is controlled as the function of the Reid Vapor Pressure change of a crude oil feeding a flash tower which provides an overhead product to the depropanizer tower and flashed crude oil to an atmospheric tower. The Reid Vapor Pressure is determined from the overhead product, the flashed crude, the pressure of the vapor in the flash tower and the temperature of liquid in the flash tower. 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. The network determines the change in the Reid Vapor Pressure and when the change exceeds a limit, provides a feed forward signal corresponding to a desired temperature associated with the new Reid Vapor Pressure. The desired temperature signal is determined in accordance with the equations hereinafter disclosed.

Abstract: A method and apparatus for the separation of a normally liquid stream comprising low, high and intermediate volatility components by distilling the feed stream in a distillation zone, removing a vaporous overhead stream comprising the high volatility components together with some of the intermediate volatility component, removing from a central portion of the zone a vaporous side stream consisting essentially of the intermediate volatility component, the rate of removal of the intermediate volatility component being controlled by the liquid level of the intermediate volatility component condensed from the overhead stream and contained in a reservoir.