RU2728970C1 - Method of two-stage thermal regeneration of waste industrial fluids - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: invention relates to petrochemical and gas industry, in particular to methods of separation and purification of waste process fluids, such as amines, glycols, motor, turbine and transformer oils. Method of two-stage thermal regeneration of waste process fluids including feeding liquid into upper part of film evaporator No.1, into annular space of which flue gases are supplied from burner for heating of heat exchange tubes of evaporator, through which regenerated liquid drains by uniform layer, which provides evaporation of a large portion of the end product, and the remaining portion of the end product with contained contaminants flows to the bottom part of the evaporator, where the vapor is separated and removed from the bottom part of the evaporator No.1, and still liquor is removed and mixed with stilling liquor of rectification column, in which heavy components are condensed owing to reaction with the distillate flowing from the distillation column head, after which the obtained mixture is separated into 2 streams, wherein first is mixed with fresh raw material and supplied to film evaporator No.1, thus providing internal circulation of raw material with low content of heavy products, and second in upper part of film evaporator No.2, into annular space of which flue gases are supplied from burner for heating of heat exchanging tubes of evaporator, through which regenerated liquid drains by uniform layer, which provides evaporation of greater part of target product, and the remaining part of the end product with high content of contaminants flows into the bottom part of the evaporator, where also pairs are coming, where the pairs are separated and withdrawn from the bottom part of evaporator No.2, and still liquor is removed and most of it is mixed with feedstock of evaporator No.2 and is directed to film evaporator No.2, thus providing internal circulation of raw material with high content of heavy products, and balance excess of bottom product of evaporator No.2 is removed from plant in form of heavy processing residue, at that, the target product pairs from the bottom part of the evaporator No.1 and the evaporator No.2 are supplied to the lower part of the rectification column for further purification from heavy components, are condensed in the refrigerator and collected in the product container, wherein in order to exclude the degraded product degradation processes from the thermal action and its repeated contamination with the osmosis products, the regeneration process is carried out at an absolute pressure of 1.0–90 kPa, which is created by means of vacuum pump connected to tank for collecting cleaned product, which enables to reduce operating temperature of process in evaporator No.1 and evaporator No.2 to 200–350 °C depending on type of processed raw material.EFFECT: higher efficiency of regeneration unit for waste industrial fluids while maintaining quality of purification of end product.1 cl, 1 dwg

Description

The invention relates to the petrochemical and gas industry, in particular, to methods for the separation and purification of waste industrial fluids such as amines, glycols, motor, turbine and transformer oils.

Waste industrial fluids contain products of thermal decomposition and oxidation, corrosion products, particles of soot and coke deposits, metal particles from the surface of rubbing parts, water and various mechanical impurities. This creates great technological difficulties in the processes of utilization and recovery of these fluids.

A known method of purification of used engine oils and installation for its implementation (application for the grant of a patent of the Russian Federation 94037575, IPC B01D 36/00, publ. 27.07.1996,). According to this method, cleaning is carried out by evaporation of low-boiling fractions from a heated thin film of water-oil emulsion, which is prepared with a component ratio of 1: 0.5-10, and the oil film is turbulized on the heating surface in vacuum.

The disadvantages of this method are:

- the use of a significant amount of water, the evaporation of which requires a lot of energy;

- the impossibility of separating from the oil non-volatile macromolecular compounds and colloidal particles of various natures present in the waste oils;

- use in the design of the installation of a rotor rotating under vacuum and elevated temperature, since coking of the heated surface of the chamber walls and the deposition of solid impurities on the rotor blades leads to a decrease in the thickness of the oil film and failure of the evaporator.

There is a known method for the regeneration of waste industrial oils (RF patent No. 2326934, IPC B01D 1/22, C10M 175/00, publ. 20.06.2008), including heating the oil with saturated steam at least to 100-205 ° with the formation of a vapor-gas mixture, containing drops of oil mist and a pair of low-boiling fractions. Steam of a hot oil film flowing down the inner surface of the pipe in a heated film evaporator is subjected to condensation into an oil mist in a counterflow of cold air, after which oil droplets are separated from an air stream saturated with oil mist in an oil separator-impactor by sequential stepwise expansion-compression of the flow on paired elements "nozzle-flap".

The disadvantage of this technical solution lies in the limited functionality, since cannot be used for glycol regeneration.

There is a known method of regeneration of a saturated glycol solution (RF patent No. 2257945, IPC B01D 53/14, B01D 53/26, B01D 3/00 publ. 08/10/2005), including preheating it, withdrawing the glycol solution from the bottom of the mass exchange column, heating it in the evaporator, supply of the vapor phase formed in the evaporator to the lower part of the column, refluxing it in the upper part of the column and removing the regenerated glycol from the evaporator. The glycol solution fed to the regeneration is divided into at least two parts, one of which is fed without heating to reflux the column top vapors and then to the evaporator, and the rest is heated and fed directly to the evaporator.

The disadvantage of this method is a decrease in the efficiency of the system when using an intermediate heat carrier - water vapor, which is problematic for installations located in the regions of the Far North. Also, the disadvantages of the method include the bubble boiling of glycol on the surface of the evaporator tubes, which leads to the deposition of salts on the tubes of the heat exchangers.

There is a known method of thermal regeneration of waste process fluids (RF patent No. 2694771, IPC S10M 175/00, B01D 1/22, B01D 53/00, publ. 16.07.2019), including the supply of liquid to the upper part of the film evaporator, into the annular space which flue gases are fed from the burner to heat the heat exchange tubes of the evaporator, ensuring that the liquid flows in the form of a film along their inner surface into the bottom of the evaporator, where vapors and residues of non-evaporated liquid also enter, then the bottom liquid is mixed with the bottom liquid of the strengthening column, in which condensation is carried out heavy components due to the interaction with the distillate flowing down from the packing of the reinforcing column, which is fed as reflux to the upper part of the reinforcing column, and the distillate is obtained from non-condensed vapors by cooling in a refrigerator, from where it is sent to a vessel for collecting the distillate, from which the distillate is also sent to the upper part of the film evaporate for its repeated purification, while the heavy products formed as a result of distillation of light components are removed from the bottom part of the film evaporator and the bottom part of the reinforcing column and, after mixing in the pipeline, most of it is pumped for mixing with the spent liquid supplied for regeneration, and the mixture is fed to the upper part of the film evaporator, thus ensuring the internal circulation of heavy products, and the smaller one, which constitutes the balance excess of heavy products, is removed from the system, and a vacuum pump is created in the distillate vessel with a vacuum pump, providing a reduced pressure in the regeneration unit in the range of 1.6-30 kPa, which allows you to reduce the process temperature to 200-350 ° C and prevent the processes of thermal destruction of the cleaned liquids.

The disadvantage of this method is the insufficiently high productivity of the installation, due to the need to organize a high circulation rate to exclude the violation of the hydraulic operation of the evaporator, and, as a result, drying out of its tubes, decomposition of regeneration products, formation of deposits and a decrease in the thermal efficiency of the installation.

The objective of the invention is to ensure high productivity of the plant for the regeneration of waste industrial liquids while maintaining the quality of purification of the target product.

The technical result of the invention is to increase the productivity of the plant for the regeneration of waste industrial liquids while maintaining the purification quality of the target product.

The problem is solved and the technical result is achieved by the method of two-stage thermal regeneration of waste industrial fluids, including the supply of liquid to the upper part of the film evaporator No. 1, into the annular space of which flue gases are supplied from the burner to heat the heat exchange tubes of the evaporator, through which the regenerated liquid flows in a uniform layer, which ensures evaporation of most of the target product, and the rest of the target product with the contained pollutants flows into the bottom of the evaporator, where the vapors are separated and removed from the bottom of the evaporator No. 1, and the bottom liquid is removed and mixed with the bottom liquid of the distillation column, in which heavy components are condensed due to the interaction with the distillate flowing down from the packing of the distillation column, after which the resulting mixture is divided into 2 streams, the first being mixed with fresh raw material and fed to the film evaporator No. 1, thus providing internal ny circulation of raw materials with a low content of heavy products, and the second to the upper part of the film evaporator No. 2, into the shell space of which flue gases are fed from the burner to heat the heat exchange tubes of the evaporator, through which the regenerated liquid flows in a uniform layer, which ensures the evaporation of most of the target product, and the remaining part of the target product with a high content of pollutants flows into the bottom part of the evaporator, where vapors also enter, where the vapors are separated and removed from the bottom part of the evaporator No. 2, and the bottom liquid is removed and most of it is mixed with the raw material of the evaporator No. 2 and sent to the film evaporator No. 2, thus providing internal circulation of raw materials with a high content of heavy products, and the balance surplus of the bottom product of evaporator No. 2 is removed from the unit in the form of heavy processing residue.

Vapors of the target product from the bottom of the evaporator No. 1 and evaporator No. 2 enter the lower part of the rectification column for additional purification from heavy components, condense in the refrigerator and collect in the product tank, and in order to exclude the processes of degradation of the purified product from temperature exposure and its re-contamination with resin products, the regeneration process is carried out at an absolute pressure of 1.0-90 kPa, which is created using a vacuum pump connected to the container for collecting the purified product, which allows to reduce the operating temperature of the process in evaporator No. 1 and evaporator No. 2 to 200-350 ° С depending on the type of processed raw materials.

The technical result of the invention is achieved through the installation of 2-film evaporators, forming 2 circulation circuits, the raw material between which is divided in a mass ratio of 5-30: 1 (circuit 1: circuit 2), and in the raw material supplied to the evaporator No. 1, a reduced content is always maintained contaminants due to the supply of fresh raw materials and maintaining the circulation ratio of 1-10: 1 relative to the raw material consumption, which allows evaporating up to 70% of the mass of the target product from this stream and ensuring high productivity of the plant for raw materials, and in the raw material supplied to the evaporator No. high content of pollutants, due to evaporation of up to 95% of the mass, of the target product, which ensures minimal product losses with the still bottoms removed from the installation, and the regeneration process is carried out at an absolute pressure of 1.0-90 kPa, which is created using a vacuum pump, which allows you to reduce the operating temperature of the process in evaporators to 200-350 ° C, depending on the type processed raw materials and exclude the processes of thermal degradation of the purified product.

The essence of the invention is illustrated by a schematic diagram of an installation for implementing a method for thermal regeneration of waste process fluids.

The installation contains a pump 1, a film evaporator 2, a rectification column 3 with a nozzle 24, a burner 6, a chimney 8, a film evaporator 14, a burner 15, a chimney 17, a refrigerator 26, a container for collecting distillate 28, a pump 29, a vacuum pump 33.

The method is carried out as follows.

Raw materials (spent process liquids) are mixed with a recirculating stream of heavy products supplied by pump 1 from the bottoms of the film evaporator 2 and the distillation column 3 and fed through pipelines 4 and 5 to the upper part of the film evaporator 2, where they flow in the form of a film along the inner surface of the heat exchangers. evaporator pipes. The heat exchange tubes of the film evaporator 2 are heated by hot flue gases, which are fed from the burner 6 through the pipeline 7 to the shell side of the evaporator 2, and the flue gases that have given off their heat are sent to the chimney 8 for emission into the atmosphere.

The liquid, continuously flowing down the tubes of the film evaporator, forms vapors of the target product, which, with the remaining non-evaporated liquid, enter the bottom of the evaporator 2, where the vapors are separated from the liquid due to separation and are removed from the apparatus through the pipeline 9. Heavy products formed as a result of the distillation of light components ( resin) is withdrawn from the bottom of the film evaporator 2 through pipeline 10, mixed with the bottom product of the distillation column 3 supplied through pipeline 11 and then through pipeline 12 are fed to the intake of pump 1, with which most of the heavy products are fed through pipeline 4 to pipeline 5 for mixing with fresh raw material and then into the film evaporator 2, while forming a loop of internal circulation of the mixed raw material with a low content of heavy products (resins), and a smaller one, in order to deeper extraction of the target product through pipeline 13, is sent as raw material to the upper part of the film evaporator 14 where they drain in the form of a film on the inner surface of the evaporator heat exchange tubes. The heat exchange tubes of the film evaporator 14 are heated by hot flue gases, which are fed from the burner 15 through the pipeline 16 to the shell side of the evaporator 14, and the flue gases that have given off their heat are sent to the chimney 17 for release into the atmosphere.

The liquid, continuously flowing down the tubes of the film evaporator 14, forms vapors of the target product, which, with the remains of non-evaporated liquid, enter the bottom of the evaporator 14, where the vapors are separated from the liquid due to separation and are removed from the apparatus through the pipeline 18.

The heavy products (resins) formed as a result of stripping off the light components are removed from the bottom of the film evaporator 14 through the pipeline 19 and by the pump 20 through the pipeline 21 are fed to the pipeline 13 for mixing with the feed of the film evaporator 14, thus forming an internal circulation loop of the mixed feed with a high content heavy products (resins), and the balance surplus of the bottoms product with a high resin content is removed from the unit via pipeline 22.

The vapors of the target product coming through the pipeline 9 from the bottom of the film evaporator 2 and through the pipeline 18 from the bottom of the film evaporator 14 are mixed and through the pipeline 23 are sent to the bottom of the distillation column 3, where they are irrigated with the purified product flowing down from the contact devices 24, which leads to condensation of heavy components and additional purification of the target product vapors from them. The non-condensed vapors of the target product from the top of the rectification column 3 are sent through the pipeline 25 to the refrigerator 26, where, as a result of cooling, they are condensed and through the pipeline 27 are removed to the vessel 28 for collecting the purified target product.

From the vessel 28, the distillate is fed by the pump 29 through the pipeline 30 as reflux to the upper part of the distillation column 3, and the balance excess of the distillate, which is the target product, is removed from the installation through the pipeline 31.

For starting the installation, stopping, as well as re-cleaning the target product, the purified product is fed through pipeline 32 to pipeline 5 and, after mixing with the raw material, to the upper part of the film evaporator 2.

In order to exclude the processes of degradation of the purified product from temperature exposure and its re-contamination with resin products, the regeneration process is carried out at an absolute pressure of 1.0-90 kPa, which is created using a vacuum pump 33 connected to the upper part of the container 28 for collecting the purified product, which leads to to reduce the operating temperature of the process in evaporator 2 and evaporator 14 to 200-350 ° C, depending on the type of processed raw materials.

Thus, the proposed invention makes it possible to increase the productivity of the plant for the regeneration of industrial liquids while maintaining the quality of the purification of the target product.

Claims (1)

A method for two-stage thermal regeneration of waste industrial liquids, including feeding a liquid into the upper part of a film evaporator No. 1, into the annular space of which flue gases are supplied from a burner to heat the heat exchange tubes of the evaporator, through which the regenerated liquid flows down in a uniform layer, which ensures the evaporation of most of the target product, and the rest of the target product with the contained pollutants flows into the bottom part of the evaporator, where the vapors are separated and removed from the bottom part of the evaporator No. 1, and the bottom liquid is removed and mixed with the bottom liquid of the distillation column, in which the heavy components are condensed due to interaction with flowing down from the packing distillation column with distillate, after which the resulting mixture is divided into 2 streams, the first being mixed with fresh raw material and fed to the film evaporator No. 1, thus providing internal circulation of raw materials with a low content of heavy food uktov, and the second into the upper part of the film evaporator No. 2, into the shell space of which flue gases are fed from the burner to heat the heat exchange tubes of the evaporator, through which the regenerated liquid flows in a uniform layer, which ensures the evaporation of most of the target product, while the remaining part of the target product with high content of pollutants flows down into the bottom part of the evaporator, where vapors also enter, where the vapors are separated and removed from the bottom part of the evaporator No. 2, and the bottom liquid is removed and most of it is mixed with the raw material of the evaporator No. 2 and sent to the film evaporator No. 2, providing such Thus, the internal circulation of raw materials with a high content of heavy products, and the balance excess of the bottom product of the evaporator No. 2 is removed from the unit in the form of a heavy processing residue, while the vapors of the target product from the bottom part of the evaporator No. 1 and the evaporator No. 2 enter the lower part of the distillation column for additional cleaning from heavy to components, are condensed in the refrigerator and collected in a product tank, and in order to exclude the processes of degradation of the purified product from temperature effects and its re-contamination with resin products, the regeneration process is carried out at an absolute pressure of 1.0-90 kPa, which is created using a vacuum pump connected to containers for collecting the purified product, which allows to reduce the operating temperature of the process in evaporator No. 1 and evaporator No. 2 to 200-350 ° C, depending on the type of processed raw materials.

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