RU5930U1 - PHASE SEPARATOR FOR UNITS OF VACUUM REFINING OF OIL RAW MATERIALS - Google Patents

Abstract

1. A device for separating unstable emulsions generated during the operation of a pump-ejector installation for vacuum distillation of petroleum feedstock, including a container with steam inlet gas inlets with an emulsion of their condensate and phase inlet, an inlet and separation zone with gas and liquid phase outlet pipes, characterized in that the input node is made in the form of a condensing zone of the separator-phase separator, separated from the rest of its internal space by a vertical bellows partition separating the capacity of the separator-phase separator the zone, the first of which is made in the form of a condensing zone, and the other, communicated with it through the upper transfer channel formed between the upper section of the bellows septum and the inner surface of the separator-phase separator tank, is equipped with gas separating and coalescing elements, while the gas separating elements are located above coalescing elements and made in the form of inclined shelves with drainage of the condensate emulsion in the direction of the bellows septum. 2. The device according to claim 1, characterized in that the gas separating elements are made with upward convexities and gas evacuation channels located in the central part of the convexities. The device according to claim 1, characterized in that the gas separating elements are made of expanded metal sheet with an arched shape of notches.

Description

Phase separator for vacuum distillation of crude oil.

The invention relates to devices for separating emulsions of immiscible liquids, in particular to phase separators for vacuum distillation of petroleum feedstocks and can be used in oil refining, petrochemical, gas processing and other industries, while improving the environment.

With an increase in the productivity of vacuum distillation units for petroleum feedstock, the need for high-performance separators - phase separators installed on the output lines of vacuum-generating devices, for example, ejectors, increases. These separators - phase separators (hereinafter - SF) should have the smallest installation area with a high specific volumetric capacity.

SF is known from the prior art, comprising a rectangular housing with a tangential emulsion inlet nozzle, an emulsion slot distributor, overflow thresholds for outputting a light phase, emulsion and suspension with nozzles and T-shaped pipelines, a water seal with a nozzle and a T-shaped piping, front and rear transverse partitions dividing the internal space of the housing into the inlet, settling and outlet chambers and at least two placed in the settling chamber one above the other with a gap of the separation module, each of which Execute of identical hollow inclined elements cm. AS USSR № 1,247,037.

Known SF has a not enough high specific volumetric productivity due to turbulence of the emulsion upon entering the SF, as well as the irrational arrangement of coalescing elements in the separation modules, which does not contribute to the intensification of delamination of the emulsion. Also known (which is part of the pump-ejector installation) SF, equipped with inlet and outlet pipes connected to the gas outlet pipe and the piping of the working fluid and light fraction, see USSR AS No. 1588925, cl. F 04 F 5/54, 1988 During operation, the gas-liquid mixture (in the form of an emulsion) from the ejector enters the pipeline through the SF, where the emulsion is divided into gas, light fraction and working fluid. Further, the separated gas (from SF), under pressure, enters the consumer, and the light fraction and the working fluid in separate flows enter, respectively, in the discharge line of light and heavy liquids. Due to the controlled removal of gas, light and heavy fractions from the SF, the pressure of the discharge and compression of the evacuated steam and gas in the ejector is regulated, which allows to expand the control range of the unit operation mode, increase the efficiency of separation of oil products and reduce energy costs for further treatment of wastewater and target fractions. A disadvantage of the known SF is the low volumetric productivity due to the turbulization of the gas-liquid mixture (emulsion) in the SF, which they receive into it by gas couples from the ejector. This leads to mixing of the separated phases and does not contribute to the intensification of delamination of the emulsion and coalescence of the dispersed phase. SF is also known, the inlet node of which is made in the form of a centrifugal separator having a vertical cylindrical body with a tangential inlet pipe and open upper and lower ends. Introductory node is placed in the first section of the separation tank, divided by partitions. The first section from the subsequent is separated by two partitions, between which in the middle zone there is a transfer channel. The second section is separated from the subsequent partition, the edges of which are located at a distance from the upper edge of the bottom of the tank. The subsequent sections are formed by partitions installed in alternating order, attached to the bottom, and partitions, the edges of which are located at a distance from the top and bottom of the tank, see Russian patent

No. 2053008, class In 01 D 17/028, 1996, a prototype of a utility model.

The disadvantages of the prototype is the low intensity of the cavitation separation and the relatively large installation area. In addition, coalescing agents in the form of vertical partitions are not effective enough due to the coalescence of the dispersed phase in one layer. At elevated (in terms of productivity) modes, the laminar nature of the fluid flow is disturbed and the phase separation efficiency decreases sharply.

The technical problem solved by the utility model is to increase the specific volumetric productivity of SF due to the rational use of its internal space, as well as providing the possibility of effective coalescence of the dispersed phase in a wide range of load and the composition of the separated emulsions.

The solution to this problem is ensured by the fact that in the device for separating unstable emulsions generated during the operation of the pump-ejector installation for vacuum distillation of petroleum feedstock, which includes a container with steam inlet gas inlets with emulsion of their condensate and phase inlet, inlet unit and separation zone with outlet branch pipes of gaseous and liquid phases, according to a utility model, the input unit is made in the form of a condensing-coalescing zone of the SF, separated from the rest of its internal space by a vertical bellows partition with the formation of a water seal and separating the capacitance of the SF into zones, the first of which is made in the form of a condensing zone, and the other communicates with it through the upper transfer channel, formed between the upper section of the bellows septum and the inner surface of the container of the SF, equipped with gas-separating and coa / gas elements while the gas separating elements are located above the coalescing elements and are made in the form of inclined shelves with the discharge of the condensate emulsion in the direction of the bellows septum. Additionally, the gas separating elements can be made with upward convexities with gas outlet channels located in the central part of the convexities or, for example, from an expanded metal sheet with an arched shape of perforations.

In FIG. - presents a schematic diagram of the proposed device;

figure 2 shows an embodiment of the device;

Fig. 3 shows a fragment of an embodiment of a gas separating element;

figure 4 shows a fragment of a variant of implementation of the gas separating element;

Fig. 3 shows an embodiment of the device;

6 shows an embodiment of a coalescing element;

7 shows a variant of the arrangement of the coalescing element.

A device for separating unstable emulsions contains a container 1 with nozzles, respectively, 2, 3, 4, 5 — introducing combined-cycle gases with an emulsion of their condensate and withdrawing heavy, light and gas phases, an input unit made in the form of a coalescing-condensing zone (vapor input zone gas-liquid jet) 1 separator-phase separator (SF), zone

gas separation II and zone III separation of liquid phases (with the corresponding branch pipes for the removal of gaseous and liquid phases), a vertical bellows septum 6 separating zone I from the rest of the inner space of the SF and communicated with it through the upper regrind channel 7 formed between the upper cut of the bellows septum and the inner surface of the capacity of the separator-phase separator. The gas separating elements 8 and 9 are made in the form of inclined shelves installed at an angle of "5 - 6, to ensure emulsion discharge without stalling phenomena, which merges towards the bellows septum 6. Coalescing elements 10 are located below the gas separating elements and can be made in the form of either a package parallel parallel plates mounted with an inclination relative to the longitudinal axis of the SF, or (in embodiments) in the form of a package of V-shaped plates (see Fig. 6,7) also installed horizontally or at an angle to the relatively longitudinal axis SF, not lower than the angle of the liquid Also, before coalescing

lamellar elements 10 can be located additional, for example, bulk coalescing element 11 (see figure 5). This element can be made in the form of an integral non-partition of porous fluoroplastic, or, as shown in Fig. 5, in the form of coalescing chips, for example, fluoroplastic, placed between perforated partitions 12 and 13.

To improve the conditions for separating gas from the emulsion, the gas-separating elements can be made either with upward convexities and gas outlet channels 14 located at the tops of the convexes (see Fig. 3), or these elements can be made of expanded-compressed sheet with an arched shape of perforations ( see Fig. 2,4).

In an embodiment, a preliminary coalescing chamber is placed in zone I, in the form of a space limited by perforated baffles 15 and 16 with coalescing chips, for example fluoroplastic. The removal of the excess heavy phase from the input unit can be carried out along line 17 with a control valve. A measuring tube 18 connected to the bottom and, rather, parts of the internal space of the SF allows you to control and set the necessary level of the heavy phase, the excess of which either merges or is sent to line III through line 17. In another embodiment, coalescing

the elements can be separated by partitions 19 and 20, and the sections formed by these partitions can be hydraulically connected by a line 21 provided with bypass valves (see figure 5).

The utility model works as follows.

The emulsified jet of water-saturated and gas-saturated hydrocarbon medium enters through input port 2 into zone 1 of the SF. Since the jet is introduced into the liquid layer,

intense heat transfer of the input stream by the liquid and quenching of its kinetic energy occurs. Due to the fact that the jet is introduced into a limited space, pulsations develop in the liquid layer and oscillations with a wide spectrum of frequencies are generated (this phenomenon is known as the Hartmann effect). Due to the heterogeneity of the emulsion (in composition and

the size of the globules - i.e. aggregate formations), they absorb wave energy in a well-defined spectral range (due to the resonance of particles with their frequencies determined by the particle size - at different frequencies due to different particle sizes of the dispersed phase globules). This leads to the merging and enlargement of the globules even before they enter the emulsions in contact with coalescent. In this regard, the larger the globule path from the lower cut of the inlet pipe 2 to the septum 16, the more effective the further emulsion separation will be.

The fact that the oscillations of an emulsion (under certain conditions) contribute to the coalescence of its dispersed phases is widely known, see, for example, In the World of Inaudible Sounds, I.G. Khorbenko, Mechanical Engineering, Moscow, 1971, p. 107.

It should be noted that upon reaching a certain level of oscillation capacity, instead of coalescence, dispersion will occur with the formation of a very stable emulsion.

Combined gas entering the receiving unit together with the emulsion is intensively separated, including under the influence of generated oscillations, while the emerging vapor-gas bubbles have a flotating and coalescing effect on the dispersed phase of the emulsion (the bubbles also pulsate under the influence of vibrations transmitted by the liquid phase and increase in sizes). Thus, zone I is essentially also

zone of primary coalescence. With further movement, the emulsion enters either directly to the gas separating elements, or (in an embodiment) to the preliminary coalescing chamber of the zone I, in which small emulsion inclusions adhere well

fluoroplastic crumb surfaces wetted by oil products are coarsened and washed off by a stream of liquid and gas. At certain input speeds and the aspect ratio of structural elements in zone I, this effect is significantly enhanced.

Next, the emulsion is poured dropwise 7 into zone II and a thin layer (for the most favorable gas separation) flows down on surfaces 8 and 9 falling into zone III, where the final process of formation of layers of fractions takes place. By introducing the emulsion flow into zones II and III in laminar mode, secondary dispersion is prevented and at the same time optimal conditions for gas separation are ensured. The intensification of the coalescence of dispersed phases in zone III (there may be several phases) is achieved

due to the implementation of this process in thin layers of liquid between the plates of the coalescing element 10, while due to the slope of its plates, the inter-plate space is constantly released, since the heavier phase flows by gravity into the bottom region, and the light phase pops up and accumulates in the upper layer. If necessary, the coalescence process can be further intensified by installing an additional coalescing element in front of the main coalescing element, for example, of a porous fluoroplastic (pore size 10 μm or more), or as shown in FIG. 5 of fluoroplastic crumb, the material of which is wetted by oil products (gasoline, diesel fuel, kerosene) and not wetted by water. Petroleum products easily pass through the coalescing material, and finely dispersed particles of emulsion water, which have a stable shell on the outside, for example, from diesel fuel, penetrating into the pores of the coalescing material or into the gaps between crumbs (in the case of bulk execution), move slowly and sticking the shells to the coalescing surface colliding with each other, these shells are destroyed, merged and pressed through the pores of the material or the gaps between the coalescing surfaces, are enlarged and in the form of enlarged to Apel water, which subsequently settles (in thin layers) and emerge as one of the heavy phases. Then the emulsion containing the already enlarged dispersed phase is sent to the plate coalescing element, where accelerated fusion in the interplate thin layers of enlarged droplets and the final phase separation takes place. Preliminary coalescence of the smallest globules (particles) of the emulsion creates the most favorable conditions for the final phase separation and allows to achieve maximum purity of the separated phases. This is also very important when treating wastewater from oil products (it is known that oil refineries are one of the main water pollutants).

To prevent violations of the separation, which may occur due to uncontrolled removal of a heavy liquid (phase) from the SF (the entire heavy layer may leave, which will lead to a breakdown of separation), the proposed device can be additionally equipped with special means. Figure 2 shows one of the possible schemes for solving this problem with a dotted line (a scheme is given of one of the known methods for maintaining the liquid separation level always at a certain height, see, for example, the book by A.I. Skoblo et al., Processes and devices for oil refining and the petrochemical industry, Gostoptekhizdat, Moscow, 1962, s327-328.).

According to the laws of hydrostatics, there will be an equilibrium above the separation plane at Lm, Ut, wherefrom you can find the height of the discharge of the heavy liquid (phase) h over the desired position of the mirror of separation, if the height of the discharge of the light liquid and the specific gravities of the liquids and the liquids are known.

When separating emulsions with a very low content of one of the components, it is advisable to pre-fill zone I with this component to the volume you make;

"0.5 of its volume., While the formation is divided, its layer in zone III is accelerated.

In embodiments and accordingly implementation of the method, see FIG. 5, the hydraulic connection of the bottom space of the SF partitioned by partitions 19 and 20 allows the bypassing of the already separated heavy phase to the outlet pipe 3, which further intensifies the process of emulsion separation, since it reduces the load on the coalescing elements.

In all variants of implementation, control valves are installed on all outlet pipes, which allows controlling the phase separation process by quickly changing the thickness of the phase layers in all zones of the SF. It has been experimentally established that the correct adjustment of the level of the heavy phase in zone I, which is actually a resonator, is of particular importance. The height of the level of the heavy phase in this zone, and therefore directly dependent on this level, the volume of the annular space determines the frequency characteristics of the resonator of zone I. The height of the level of the heavy phase in zone I depends on many factors, for example, the speed and temperature of the input stream of the mixture of phases, specific the weight of the substances that make up the emulsion, etc. The practically optimal operating mode of the SF is experimentally selected by controlling the rates of removal of the separated phases.

Experimental work on the separation of emulsions was carried out at different input speeds and concentration compositions of the initial mixtures. The separation of unstable emulsions formed by water and mineral oil such as BM-6, water and diesel fuel, a solution of caustic soda in hot water, etc. showed that the proposed utility model provides effective separation of a wide spectrum (in the composition and nature of the components) of unstable emulsions and is efficient in a wide range of performance loads.

Claims (3)

1. A device for separating unstable emulsions generated during the operation of a pump-ejector installation for vacuum distillation of petroleum feedstock, including a container with steam inlet gas inlets with an emulsion of their condensate and phase inlet, an inlet and separation zone with gas and liquid phase outlet pipes, characterized in that the input node is made in the form of a condensing zone of the separator-phase separator, separated from the rest of its internal space by a vertical bellows partition separating the capacity of the separator-phase separator the zone, the first of which is made in the form of a condensing zone, and the other, communicated with it through the upper transfer channel formed between the upper section of the bellows septum and the inner surface of the separator-phase separator tank, is equipped with gas separating and coalescing elements, while the gas separating elements are located above coalescing elements and made in the form of inclined shelves with the discharge of the condensate emulsion in the direction of the bellows septum.  2. The device according to claim 1, characterized in that the gas-separating elements are made with upward convexities and gas evacuation channels located in the central part of the convexities. 3. The device according to claim 1, characterized in that the gas separating elements are made of expanded metal sheet with an arched shape of notches.