UA10678U - A process for an extractive purification of aqueous solutions from admixtures - Google Patents

Abstract

A process for the extractive purification of aqueous solutions from admixtures involves contacting two liquid immiscible phases in mixing liquid phase in the form of cleaning liquid with the liquid phase in the form of liquid extragent, discharge and dividing the cleaned liquid for the final after-purification thereof and liquid extragent with admixtures for settling and division into regeneration for the repetitive use, intensification of contacting liquid phases while mixing in the continuous mode of counterflow of liquid phases, forming volume zones of microdripping contacting in the conditions of continuous concentration of liquid phases in the extactor volume.

Description

Description of the invention

The useful model refers to chemical technology, mainly to the field of coal 2 phenolate processing, obtained directly after the dephenolization operation of coke chemical raw materials and for the processing of other aqueous solutions using coal or other oils as an extractant and can be used in the conditions of multiton production of coke chemical enterprises and phenol plant.

There is a lot of scientific, technical and patent information on the problem of processing coal tar obtained at coke chemical plants in the process of coking coal with the aim of obtaining 70 different chemical products. Phenolic raw materials are processed according to a complex multiphase technological scheme, the development of which over time obeyed the requirements of improving the quality of phenolic products, technical and economic indicators of production and environmental protection. In the monograph by T. Ya. Gogoleva, V. I. Shustikov, Chemistry and technology of coal tar processing, Moscow, Metallurgy, 1992. |1| provides basic information on phenols (p. 77-80), coal oil as an absorber of benzene hydrocarbons (p. 90-100), processing of 12 fractions of countercurrent liquid extraction (section 5.4, p. 198), extraction of phenols from fractions, separation of nitrogenous bases from fractions of coal tar (p. 204).

Sodium phenolates are first purified from nitrogenous bases by extracting them with coal oil, and then, in the second stage, nitrogenous compounds remaining in the aqueous solution and other impurities are desorbed with steam.

The current level of removal of nitrogenous bases from phenols in total for two stages of purification is 80-85965, which corresponds to a decrease in their number in sodium phenolates from 0.395 to 70.0595. The monograph concludes that in order to achieve a deeper degree of purification of phenolates from bases, it is necessary to use the extraction of coal oils and steam desorption in several stages in multi-stage devices.

It is also stated that at domestic coke chemical enterprises, the extraction of phenols from fractions is carried out in vertical empty extractors with countercurrent movement of the fraction and the extractant or by mixing the latter in an ejector, ball extractors and settling in separators. -at

Extraction, along with rectification, is one of the main methods of separation of liquid homogeneous mixtures, solutions.

The extraction method is based on the extraction of one or more dissolved substances, for example, in the form of impurities from one liquid with the help of another liquid (extractant), which practically do not mix or partially mix with the cleaning liquid. In the process of mixing the solution that cleans and the extractant, impurities are distributed in different proportions between the indicated liquids, which do not mix. According to the distribution law, the ratio of the concentration of impurities in the extractant and in the solution of the cleaning liquid after their contact depends on the nature and amount of impurities and the extractant, the concentration of the solution of the cleaning liquid, temperature, and pressure. eh

The ratio of equilibrium concentrations of substances distributed between two liquid phases at a constant Ga») temperature is a constant value called the distribution coefficient. In fact, in non-equilibrium conditions during the cleaning operation, the distribution coefficient can significantly depend on the local concentration of the respective liquid phases.

In the considered case, the general decision on the extractive purification of phenolates from impurities is mainly based on the example of the process of extractive purification of phenolates from impurities, with the spread of its "essential features, in particular, on the method of cleaning soda solutions from impurities after the decomposition of phenolates with carbon dioxide gas and on the method of desalination of phenols . c To ensure a low content of pyridine bases, a two-stage scheme is currently generally accepted

From" processing of phenolates: 1) preliminary purification of phenolates by extraction with coal oil; 2) subsequent steam desorption of all volatile impurities. G. A. Markus, G. A. Kachuk. Extraction of nitrogenous bases from phenolate solutions. Coke and chemistry, 1967, Mo8, pp. 30-331I21.

The disadvantages of the method of removing non-phenolic impurities at the stage of processing phenolates include the need to process a large amount of solutions, because aqueous solutions of phenolates contain no more than av! 17-2095 phenols; low concentration of impurities (0.3-0.595 nitrogen bases and 0.3-196 neutral oils); the presence in phenolates of such impurities as organosulfur compounds, silicates, aluminosilicates and compounds of a polymeric nature, which are released from solutions when their physicochemical properties (temperature, concentration, pH) change and thereby complicate the equipment design of purification processes.

However, the methods associated with the removal of impurities from the final phenolic products, proposed back in the 60s of the last century, have not yet found wide industrial application. Dirichs A., Kubichka R. Phenols and bases from coal. Gostoptekhizdat, 1958, pp. 202-211|3), asst. USSR, Mo 112640, 1957, || English Stalemate. Mo. 714651, 10.09.1954 |5). 29 The hardware design of the extraction process is known and described, for example, in Ch. 13 books by A. N. Planovsky, P. I. Mykolaiv, Processes and devices of chemical and petrochemical technology. M. Chemistry, 1987|6). Well-known tubular mixers (p. 336, fig. 13.19c) consist of two concentric pipes into which liquids enter separately. From the holes of the inner pipe, liquid flows out at high speed into the annular gap between the pipes and mixes with the liquid phase. 60 The disadvantage is that the use of diaphragm and tube mixers requires the installation of two pumps on the input lines of each phase.

Known (p. 339) column extractors, in particular without packing empty, spray extractors or blown columns, in which the phase contact surface develops as a result of the dispersion of a drop of one liquid phase (dispersed) in another liquid phase (solid or dispersed). The dispersed phase can be both a light liquid and a heavy liquid.

The load of the apparatus to ensure the optimal mode of extraction according to the consumption of liquid phases should be chosen so that it does not occur, for example, the accumulation of the dispersed phase with flooding of the reactor. This leads to a narrowing of the passage for the continuous phase and, accordingly, to an increase in its speed and, in the final account, to a deterioration of the extractive purification performance.

As a prototype for the purpose and the result that is achieved, the first stage of the two-stage system of depyridination is adopted: the method of extraction of nitrogenous bases from phenolates and regeneration of the solvent, described in the reference cited above, I|2): Cox and Chemistry, 1967, Mo 8, with. 30-33. On p. 31 article of the prototype shows the extraction scheme. 70 The phenolate solution separated from the oils from the storage and the coal absorbing oil, partially phenolized and depyridinated, from the intermediate tank are supplied for mixing at the entrance of the venter pump according to a continuous scheme in an optimal ratio of 2:1. This water mixture is transferred to a settling tank for long-term settling for separation into components. When the phenolate solution comes into contact with coal oil, the pyridine bases are distributed between the two solvents. At the same time, the solubility of pyridine bases in the absorbent oil is 7/5 times higher and this contributes to their removal from the phenolate solution.

Production experience shows that the optimal condition for the extraction process is the content of phenols in the extractant in the range of 2-3905.

Upon completion of the separation from the lower part of the sedimentation tank, the settled phenolates flow into the storage, from where they are collected for the second stage of purification of phenolates from pyridine bases by desorption with blind 20 steam. From the upper part of the storage, the absorbent oil separated from phenolates, saturated with nitrogenous bases, is fed to the additional sediment in the tank and then to the depyridination facility, from which the depyridinated oil enters the intermediate tank.

After extraction of pyridine bases with coal oil from a solution of prepared phenolates with a base content of 0.3295, up to 0.1295 pyridine bases, 0.395 neutral hydrocarbons and up to 0.0495 ammonia remain in the phenolates as impurities.

The general features of the prototype and the claimed process of cleaning water solutions from impurities are: o, - the process of extractive cleaning of water solutions from impurities; - contact of a liquid that does not mix and cleans, and a liquid extractant, in the required ratio when they are mixed; so z o - removal and separation of the purified liquid for residual purification, and the liquid extractant with impurities for sedimentation and separation with subsequent regeneration for reuse. -

The basis of the proposed solution is the task of increasing the efficiency of the extractive purification of He water solutions from impurities, primarily during the extraction of nitrogenous bases from phenolates with coal absorbent oil, by intensifying the mode of contact of immiscible liquids. at

The task is solved by the fact that in the process of extractive purification of aqueous solutions from impurities, "which consists in the contact of two immiscible liquid phases, when mixing the liquid phase in the form of a cleaning liquid with the liquid phase in the form of a liquid extractant in the selected ratio , removal and separation of the purified liquid for its residual purification, and the liquid extractant with impurities for settling and separation with subsequent regeneration for reuse, according to a useful model, carry out "intensification of contact of liquid phases during mixing in the volume of a vertical empty extractor in a continuous the regime of counterflow of liquid phases with the formation in the volume of the extractor along its height of two opposite volumetric zones of microdroplet contact under conditions of continuous change in the concentration of liquid phases, ;" and one of the specified volume zones is located at the place of introduction of a heavier liquid from the top of the extractor with its movement from top to bottom, and the other of the specified volume zones is located, respectively, in the lower part of the extractor with movement of a less heavy liquid from bottom to top, and the intensification contacting - provide due to additional turbulization of each of the specified volume zones by forced supply under pressure of finely divided jets of the corresponding liquid phases. o The features listed above constitute the essence of a useful model, because they are necessary in any version

Ge" implementation and sufficient to achieve the set goal. The proposed extractive cleaning process has been experimentally developed for a number of years in parallel with the current technology in conditions

Sh-phenol plant for cleaning coal phenolates from impurities with coal absorbent oil as an extractant. The proposed extractive purification process is experimentally used also for the purification of the soda solution after decomposition of phenolates with carbon dioxide and for the operation of desalination of raw phenols.

A specific difference in the process of extractive cleaning is that in the case of cleaning phenolates from nitrogenous bases with an extractant - coal absorbent oil, the phenolates that are cleaned are injected with jets under a pressure of 2-Zatm from the top of a vertical empty extractor with a volume of b3m3 and a diameter of 27 m3/hour 2m through holes with a diameter of 5mm in the walls of tubular mixers, evenly distributed in the volume, submerged to a depth of 0.5m, coal absorbent oil at a temperature of 45-55 "C is injected with 60 jets under a pressure of 2-Zatm through holes with a diameter of 5mm evenly into the upper hemisphere of the extractor volume to meet the flow of phenolates in the amount of 5095 from the specified hourly consumption of phenolates, with the provision of hourly productivity for purified phenolates in the range of 10-1v8t/hour.

A specific difference is that sodium phenolates with an initial content of pyridine compounds of 0.32905 after extraction contain, o: b5

Raw phenols, not more than 24;

Pyridine compounds, no more than 0.03-0.08

Another specific difference is that in the case of cleaning the soda solution from phenols with coal absorbent oil, a fortified soda solution with a carbonate content of 10-12.595, bicarbonate 0.8-1.895, phenols - no more than 3.295, coal absorbent oil is fed into the lower part of the empty extractor at a temperature of 40-602C in a ratio of 1:2 to the volume of the solution with a phenol content of no more than 1905 and pyridine bases no more than 4-695, and a soda solution is taken from the bottom of the empty extractor with a phenol content of no more than 0.1595. 70 Another specific difference is that in case of desalination of phenols, raw phenols from the storage are fed to the top of the empty extractor, condensate is fed to the lower part of the extractor after evaporation of the soda solution, salt solution is obtained from the top of the extractor, and raw phenols with the content are removed from the bottom of the extractor of salts 0.1-0.390.

The novelty of the proposed solution consists in the formation in the places of introduction of two liquid phases into the empty /5 extractor of two volume zones with intense droplet interaction under conditions of non-steady, but continuous change in the concentration of liquid phases as a result of additional turbulence by jets of liquids introduced under by pressure into the volume through holes of small diameter, for example 5 mm. Obviously, this leads to a change in the values of the impurity distribution coefficient at a similar organization of the droplet contact of two immiscible liquids, compared to its values in the steady state. 20 No such solution was found in the studied patent and technical literature on extractive purification of liquids. The industrial applicability of the proposed solution is obvious.

The technical and economic advantages of the proposed solution consist in achieving a high degree of purification in one stage, for example, in the purification of phenolates from nitrogenous impurities from the initial value of 0.329o to 0.059 and even less in the case of process optimization. Thus, in one stage of extraction, 8595 degrees of purification of phenolates from nitrogenous bases is achieved, which is usually achieved only in two stages of purification.

This creates additional opportunities for carrying out a technological process with a maneuver on the composition of the raw material, operating modes on the productivity of the device, etc. while ensuring regulatory indicators for product quality.

The use of well-cleaned phenolates from the very beginning of non-stop processes for the processing of raw materials has a positive effect on the quality of chemical products.

Tables 1 and 2 show data on the content of pyridine bases and neutral oils in batches of dicresol and of tricresol, respectively, obtained using the claimed solution at the first stage of purification and "from the improved second stage of the phenolate purification process in comparison with the normative indicators according to the current

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Thus, the description of the application presents a solution for improved extractive purification of phenolates with coal absorbent oil, which meets regulatory criteria for novelty and industrial applicability.

Claims (5)

60 Formula of the invention 1. The process of extractive purification of aqueous solutions from impurities, which includes the contact of two immiscible liquid phases, when mixing the liquid phase in the form of a liquid that cleans with the liquid phase in the form of a liquid extractant at a selected ratio, removal and separation of the correspondingly purified liquid for because of its residual purification, and a liquid extractant with impurities for settling and separation into regeneration for repeated use, which differs in that it intensifies the contact of liquid phases during mixing in the volume of a vertical empty extractor in a non-stop counterflow mode of liquid phases with the formation of of the extractor along its height of two opposite volumetric zones of microdroplet Contacting under conditions of constant concentration of liquid phases, which changes, and one of the indicated volumetric zones is located at the place of introduction from the top of the extractor of a heavier liquid with its movement from top to bottom, and the other with the specified volume zones are located, respectively, in the lower th part of the extractor at the point of introduction of a less heavy liquid with its movement from the bottom to the top, and the intensification of contacting is ensured by additional turbulence of each of the indicated volumetric zones of forced supply under the pressure of finely divided 7/o jets of the corresponding liquid phases. 2. The process of extractive purification according to claim 1, which differs in that in the case of purification of phenolates from nitrogenous bases with an extractant - coal oil, the phenolates that are purified are injected with jets under a pressure of 2-3 atm in a volume of 27 m U/hour from the top of a vertical empty extractor with a volume of 63 m 3, a diameter of 2 m, through holes with a diameter of 5 mm in the walls of tubular mixers, evenly distributed in the volume, submerged at a depth of 75 - 0.5 m, coal oil at a temperature of 45-552С inject jets through holes with a diameter of 5 mm under a pressure of 2-3 atm evenly into the lower part of the volume to meet the flow of phenolates in the amount of 50-95 of the indicated hourly consumption of phenolates, ensuring an hourly productivity of phenolates purified from impurities of 10-18 t/hour. 3. The process according to claim 2, which differs in that sodium phenolates with an initial content of pyridine bases of 0.32 905 after extraction contain 90: raw phenols, no more than 24 pyridine bases, no more than 0.03-0.08. 4. Extractive cleaning process according to claim 1, which differs in that in the case of cleaning soda solution from phenols with coal oil, a fortified solution of soda with a content of C carbonate 10-12 90, bicarbonate 0.8-1.8 95 is fed to the top of the empty extractor , phenols - not more than 3.2 96, coal oil is fed into the lower part of the empty extractor at a temperature of 40-602С in accordance with 1:2 to the volume of soda solution with a content of phenols not more than 1 95 and pyridine bases not more than 4-6 9o , and from the bottom of the empty extractor, a soda solution with a phenol content of no more than 0.08 95 is taken. 5. The process of extractive purification according to claim 1, which differs in that in the case of desalination of raw phenols into phenols from storage, they are fed to the top of an empty extractor, and condensate is fed to the lower part of the extractor, after evaporation of the soda solution, 1-3.5 are obtained from the top of the extractor 95 salt solution, and crude phenols with a salt content of 0.1-0.3 905 are reflected from the bottom of the extractor. - «- Official bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated microcircuits", 2005, M 11, 11/15/2005. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. " - . and? - («c) (o) -and IR e) 60 b5