RU2433162C1 - Method for separating mixed fluid containing water and oil and/or mineral oil and related equipment for implementation thereof - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention concerns a method for separating a mixed fluid containing water and oil and/or mineral oil that involves induction of a pre-selected gas including oxygen with the mixed fluid to be separated with the use of a supersonic jet pump with the gas and the fluid to be separated circulating in appropriate closed loops, separation of a steam-and-gas phase, steam condensation, collection of a condensed component; what is induced is the mixed fluid at temperature 50-90°C under pressure to provide a fluid outlet flux of 20-28 m/s, and outlet atmospheric pressure is maintained. Also, the invention concerns equipment mounted for implementing the method.

EFFECT: high-efficiency continuous separation of oil or mineral oil.

7 cl, 3 ex, 1 dwg

Description

The invention relates to methods for the separation of aqueous-organic mixtures containing water dispersed in hydrocarbons in various forms, including in the form of submicron particles, can find application in the oil and oil refining industries, transport, energy and other industries.

The separation of oil-water emulsions is carried out in various ways, depending on their condition and water content. Highly watered, persistent emulsions are difficult to dehydrate and are usually separated in a multi-stage process with the preliminary introduction of a demulsifier. As a rule, these emulsions are subjected to complex thermochemical effects, sometimes using physical methods.

A known method and installation for cleaning oil sludge, in which the separation of the oil-water emulsion is carried out by adding a demulsifier solution, is then treated with an alternating magnetic field, heated in a device equipped with acoustic systems, after which the mixture is sent for separation in a centrifuge (RU 2174957, 10/20/2001).

The disadvantage of this method is its technological complexity due to the use of various systems.

A known method of separating water-oil emulsions, in which dehydration is carried out first by settling in two sumps to a residual water content of 7-10 vol.%, And then in a three-stage electrodesalting unit when heated to 60-70 ° C and feeding 30-100 g / t non-ionic emulsifier (RU 2318865, 03/10/2008).

The residual water content according to the method was at the level of 0.6-1.2 vol.%, Which does not meet the requirements for refined oil. Another disadvantage is the technological complexity of the process.

A known method for the separation of water-oil emulsions, in which the separation process is carried out on a multi-stage combined thermochemical and electro-desalting plant at 80-120 ° C, using as a demulsifier a composition consisting of a surfactant and a water-soluble wetting agent at a total flow rate of 100-1000 g / t of the original product. According to this method, a three-stage separation process is carried out, first in a thermo-settler, adding various demulsifiers with stirring and heating to the initial product, then water is sedimented from oil products and, finally, the final separation of water and oil is carried out in two successive electric dehydrators. When carrying out the process in the range of 100-120 ° C and the introduction of reagents in the amount of 800-1000 g / t, it is possible to achieve acceptable indicators for the water content in marketable oil (at the level of 0.1-0.2%) (RU 2318865, 03/10/2008 )

The disadvantage of this method is also the technological and hardware complexity, low productivity, due to the need to use the settling apparatus.

In addition, according to the methods described above, it is fundamentally impossible to dehydrate highly viscous organic products such as M-100 fuel oil. Even after 48 hours of settling fuel oil with an initial water content of 30-40% at 90-100 ° C and adding surfactants and extractants to it, the residual water content cannot be reduced by more than two times. It is not possible to drive water from the oil-water mixture even when heated for 5-6 hours in vacuum apparatus at temperatures above 150 ° C. Heating at higher temperatures (above 200 ° C) leads to the resinification of paraffins contained in the fuel oil fraction and the loss of commercial quality.

A known method of separating water-oil mixtures, including the evaporation of water and light oil products by heating the mixture in a turbulent stream formed by gas and dispersed in it by a mixture located in a rotary evaporator, transporting the formed vapors from the apparatus to a condenser, condensation of light oil and water vapors in a heat exchanger, per-fractional collection of light petroleum products with water, aqueous phase and bottom residue. To intensify the processes of water evaporation from highly viscous mixtures, this method uses a cross motion scheme in a gas-liquid system, which is implemented in a rotary-film evaporator equipped with a contact device in the form of a tape spiral with Z-shaped bends around its perimeter, in which there is, at least one gas passage. The evaporation process is carried out at elevated temperatures in countercurrent mode. When the water-oil mixture enters the rotary-film evaporator, it is distributed under the action of centrifugal force created by the rotation of the rotor, in the form of a thin film, and in places of Z-shaped bends under the influence of the gas stream is dispersed into droplets. As a result, interphase turbulization intensifies mass transfer (UA 69779, September 15, 2004).

The disadvantage of this method is the technological complexity and energy consumption caused by the need to carry out evaporation processes with significant overheating of the initial mixture. In addition, during the evaporation of a highly viscous liquid, it cannot be distributed uniformly under the action of centrifugal forces on the contact tape device, therefore, the evaporation processes in the entire volume of the evaporator are characterized by nonequilibrium, which also leads to an excessive consumption of thermal energy.

A device for separating water-oil mixtures, including a collection of watered oil products, a stripping apparatus in the form of a cube, a vapor transport unit, a vapor condenser, collectors of dehydrated oil products, condensed light fractions and distilled water (RU 2042372, 08.27.1995).

In the known device, water is removed from various water-oil mixtures, including highly viscous products, by evaporation of water from a heated cube, which is conducted in a vacuum mode when the mixture is heated to 95-120 ° C.

The disadvantages of this device are the use of a two-stage distillation with two sequentially distant devices (large and small distillation cubes), two capacitors and a vacuum pump, which greatly complicates the hardware circuit itself, and the fact that the distillation devices are periodic operation units, which does not allow to intensify the process.

The closest in technical essence is the method of separation of a liquid mixture containing water and oil and / or oil products, including ejecting a pre-selected gas with a separated liquid mixture using a supersonic ejector during gas and separated mixture circulation along the corresponding closed loops, gas-vapor phase separation, vapor condensation, collection of condensed components (RU 2165281, 04.20.2001).

According to this method, the gas is ejected with the initial mixture at a speed of at least 30 m / s, with a temperature higher than the temperature at which the saturation pressure of the removed water is equal to the minimum absolute pressure created by the initial ejected liquid without air leakage, and this mixture is mixed with gas in a supersonic liquid-gas ejector, while ensuring a mass ratio of the total flow rate of the ejected air and the released steam of the low-boiling component to the flow rate of the initial liquid in the range 0.00001 to 0.005 m to form a supersonic two phase equilibrium mixture, maintaining constant pressure in the gas loop system and a constant vacuum in the receiving chamber of the ejector.

The disadvantage of this method is the inability to implement a continuous separation process and the complexity of the processes of maintaining a constant pressure in the gas circuit of the system and constant discharge in the receiving chamber of the ejector.

There is also known a device for separating liquid media, which contains an electric pump connected in series by pipelines, a nozzle block of a liquid-gas ejector, a sealed tank, the upper part of which is connected by a recirculation line to a device for separating a droplet entrainment of a liquid mixture from a vapor-gas mixture, a cooled condenser and condensable collectors liquids (RU 2165281, 04.20.2001).

In the known installation, it is possible to carry out both the separation of water-alcohol mixtures and the separation of light fractions of oil products (gasoline) from water, however, the installation is not effective for the separation of water from stable water-oil mixtures due to the following factors:

- the foam sludge tank or antifoam used as a device for separating the liquid phase from the gas-vapor mixture is ineffective and inefficient;

- the expansion compensator installed on the collector-drive of the condensed liquid phase does not allow for a stable operation of the ejector at atmospheric pressure.

- the installation does not allow the process of separation of oil-water mixtures in continuous mode.

The present invention is the creation of a high-performance simple and reliable method and installation for its implementation, suitable for the separation of any type of oil-water mixtures, including stable colloidal systems and highly viscous media.

The problem is solved by the described method of separating a liquid mixture containing water and oil and / or oil products, including ejecting a pre-selected gas-air with a separated liquid mixture using a supersonic ejector during gas circulation and the separated mixture through appropriate closed loops, separating the gas-vapor phase, vapor condensation, collection of the condensed component, according to which the mixture is fed to the ejection at a temperature of 50-90 ° C under pressure, ensuring the speed of the mixture at the entrance to the ejection OR equal to 20-28 m / s, while atmospheric pressure is maintained at the outlet of the ejector.

Preferably, the mixture is ejected at a temperature of 70-90 ° C. After separation of the mixture, it is possible to further purify the separated oil and / or oil products from salts.

Preferably, the salts are cleaned by contacting the oil and / or oil products with distilled water or an aqueous-alcohol mixture at a volume ratio of 1: (0.01-0.02), respectively, followed by settling of the aqueous and organic phases.

The problem is also solved by the described installation for implementing the inventive method, comprising a pipe connected tank for a shared liquid mixture, an electric pump, a heat exchanger, a supersonic liquid-gas ejector unit, a device for separating the vapor-gas phase from the liquid phase, capacitors, a container for collecting the condensed phase, a control measuring instruments, while the connecting pipelines are installed with the formation of two closed loops for the liquid and vapor-gas phases, respectively, the output the ejector’s confuser is directly connected to the device for separating the gas-vapor phase from the liquid, made in the form of a cyclone mounted vertically, the upper part of which is connected to the gas-vapor phase condenser, and the lower part to the tank for the mixture to be separated, and the said tank in the upper part is equipped with an expander the gas phase compensator and the inlet of the initial mixture, and in the lower part the outlet of the dehydrated oil and / or oil product.

The speed interval of 20-28 m / s is due to the following. The minimum value of the speed of sound in an equilibrium water-air mixture can be about 20 m / s at a mixture pressure of 1 at. Therefore, in order to realize a supersonic flow and subsequent shock-wave treatment of the two-phase mixture formed in the ejector, it is sufficient to supply the treated liquid to the ejector mixing chamber at a speed slightly higher than the speed of sound, i.e. 20 m / s. With a significant excess of this indicator, energy costs will increase sharply (for example, a 2-fold increase in the liquid velocity in the ejector automatically leads to the need to increase the supply pressure by 4 times). Therefore, for low-viscosity mixtures, it is sufficient to provide a feed rate in the range of 20-24 m / s. When separating highly viscous mixtures of water-fuel oil type to ensure normal flow and create conditions for the release of water, it was experimentally established that a necessary and sufficient sign is the provision of speed in the range of 24-28 m / s.

A diagram of the claimed installation is shown in the drawing. The operation of the installation is illustrated on a sample of a liquid oil emulsion with a productivity that ensures the removal of 6 l of water per hour from the original emulsion.

The insulated container - 1 is filled with an oil-water emulsion, then all cavities of the installation (pipelines, heat exchangers, a condenser, a separator, a compensator) are purged (filled) with a pre-selected gas-air. The hot heat carrier is supplied to the nozzle - 18 to the heat exchanger for heating the raw material - 3, from which the cooled coolant is removed through the nozzle - 19. Both water and antifreeze-like liquids can be used as the heat carrier. The process of separation of the oil-water mixture is carried out in the temperature range of 50-90 ° C.

They turn on the electric pump - 2 and circulate the separated liquid in a closed circuit: tank - 1, pump - 2, heat exchanger - 3, pipeline for supplying liquid to the ejectors - 4, nozzle blocks of ejectors - 5-1, mixing chambers of ejectors equipped with confusers at the outlet - 5-3, centrifugal separator - 6 and again the capacity - 1. The electric pump - 2 provides the absolute pressure of the liquid in front of the nozzle blocks of the ejectors, sufficient to realize a gas-liquid mixture in the ejector at a speed in the range of 20-28 m / s. Gas (air) circulates in a different circuit, consisting of sequentially installed: receiving chambers of ejectors - 5-2, block of ejectors - 5, in which it is saturated with water vapor, centrifugal separator - 6, in which gas is separated from droplets, heat exchanger - 8, in which the mixture entering the original container - 1 is heated due to the latent heat of vaporization of the condensate, condenser - 9, the condensate collection tank - 10 and the pipe - 17, from which the gas again enters the container - 1. Excess gas during thermal expansion can come from from separator - 6 into the tank - 1 and from it - into the compensator - 7, due to which pressure in the tank - 1 is constantly maintained at atmospheric pressure.

The effectiveness of the described method is illustrated by the following examples:

Example 1

Separation of an oil-water emulsion with a water content of 50% (this emulsion was not amenable to separation by conventional methods, for example, by electro-dehydration).

For processing serves the original oil emulsion with a temperature of 20 ° C and a flow rate of 3.33 g / s (12 l / h). The emulsion through the nozzle - 13 is continuously fed into the heat exchanger - 8, where it is heated by condensing water vapor from 20 ° C to 70 ° C and sent through the pipeline - 14 through an automatic feeder of raw materials with a level gauge - 15 to the bottom of the tank - 1. Provide a pump - 2 the feed pressure of the processed raw materials to the nozzle block of the ejector equal to 5 MPa, while the flow rate of the gas-vapor mixture in the ejector is 28 m / s. 472.5 kcal / h is required to heat the incoming feed to 70 ° C. During condensation, 3234 kcal is released. Thus, in the heat exchanger - 8, all incoming raw materials are heated to a temperature of 70 ° C and, at the same time, 0.146 parts of the steam passing through the heat exchanger are condensed in 1 hour. The rest of the steam is condensed in the condenser - 9 and the resulting water is accumulated in the tanks for condensate collection - 10. To ensure the operation of the condenser - 9, cold water with a temperature of 15 ° C is supplied through the nozzle - 11 and water with a temperature of 35 ° C is removed through the nozzle - 12. . The amount of water required to condense water vapor is 138 kg / h. The heat required for the evaporation of 6 l / h of water is supplied to the emulsion circulating in a closed circuit in the heat exchanger - 3 due to the heat carrier supplied and removed through fittings - 18 and - 19, heated by an independent heater (not shown). The power of this heater is designed to bring to the circulating in the emulsion installation the amount of heat necessary for the evaporation of water, taking into account possible heat losses. The performance of the installation and the degree of dehydration of the resulting oil product is changed by controlling the flow rate of the emulsion fed to the treatment. Reducing the supply of emulsion for processing reduces the amount of water in the resulting oil product. As a result of the separation of the initial oil-water mixture, an oil with a water content of less than 0.1% was obtained with an initial emulsion throughput of 12 l / h.

Example 2

The process is carried out as in example 1, except that F-5 fuel oil, in which the water content is 5%, is used as a shared raw material (according to GOST No. 10585-99, the water content in fuel oil should not exceed 0.3%) .

An initial fuel oil emulsion with a temperature of 20 ° C and a flow rate of 33.3 g / s (120 l / h) is fed for processing. The fuel oil supplied to the treatment is heated in heat exchanger -8 with heat from condensation of water vapor up to 73.9 ° C, while ensuring complete condensation of the vapor. The missing heat for heating fuel oil to 90 ° C and evaporation of a given amount of water (966 kcal) is supplied by a heat exchanger - 3. As a result of the process, fuel oil with a water content of less than 0.2% was obtained at a capacity of 120 l / h for the initial fuel oil.

Example 3

The experiment of Example 1 is carried out, except that an emulsion with a water content of 28% and salts (iron, manganese and vanadium) for a total of 0.8 g / l is fed to the separation.

After processing 20 l of the starting product, 14.41 l of refined oil with a water content of less than 0.1% is obtained. This oil is drained into a cone-shaped reactor equipped with a bottom fitting. With stirring, add 0.2 l of a 5% solution of butyl alcohol in water. After settling, this aqueous solution is drained through the bottom fitting. The metal content in the final oil product does not exceed 0.04 g / l.

In accordance with the present invention, there is provided a continuous high-performance method for the separation of water from persistent oil-water mixtures and emulsions. The claimed method and installation can also be used to separate other mixtures and solutions containing boiling components in dissolved or emulsified form.

Claims (7)

1. A method of separating a liquid mixture containing water and oil and / or oil products, comprising ejecting a preselected gas-air with a separated liquid mixture using a supersonic ejector during gas and separated mixture circulation through appropriate closed loops, separating the gas-vapor phase, vapor condensation, condensed collection components, characterized in that the ejection is fed with a liquid mixture at a temperature of 50-90 ° C under pressure, providing a speed of the mixture at the inlet to the ejector 20 - 28 m / s, while at the exit of ejectors maintain atmospheric pressure. 2. The method according to claim 1, characterized in that the mixture is ejected at a temperature of 70-90 ° C. 3. The method according to claim 1, characterized in that after separation of the mixture, the separated oil and / or oil products are purified from salts. 4. The method according to claim 4, characterized in that the cleaning of salts is carried out by contacting oil and / or oil products with distilled water or a water-alcohol mixture with a volume ratio of 1: (0.01-0.02), respectively, subsequent sedimentation of the aqueous and organic phases. 5. Installation for implementing the method described in claim 1, containing a pipe connected to a shared liquid mixture tank, an electric pump, a heat exchanger, a supersonic liquid-gas ejector unit, a device for separating the vapor-gas phase from the liquid phase, a condenser, a container for collecting the condensed phase, while the connecting pipelines are installed with the formation of two closed loops for the liquid and gas phases, respectively, the ejector output confuser is directly connected to the separation device the vapor-gas phase from the liquid, made in the form of a cyclone mounted vertically, the upper part of which is connected to the condenser of the gas-vapor phase, and the lower part to the tank for the separated mixture, and the said tank in the upper part is equipped with a gas phase expander-compensator and an inlet of the initial mixture, and in the lower part - the outlet pipe of the dehydrated oil and / or oil product. 6. Installation according to claim 5, characterized in that it contains a block of several supersonic ejectors connected in parallel. 7. Installation according to claim 5, characterized in that it is additionally equipped with a unit for cleaning salts and / or oil product separated from water, made in the form of a settling contactor.

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