SK284451B6 - Regeneration method of used low-hardening mixtures and apparatus for implementation of this method - Google Patents

Abstract

A regeneration method of low-hardening mixture consisting from decantation, filtration, contacting with active carbon, contacting with strongly acid cation exchanger, separation of alpha-, omega-dicarboxylic acid by contacting with strong alkaline anion exchanger and repeated contacting with active carbon. A final solution of monoethylene glycol in water is processed to low-hardening mixture, or monoethylene glycol is isolated by distillation from thereof. A apparatus consist of a decanter, filters, an active carbon columns, a cation exchange column, a separator of alpha-, omega-dicarboxylic acids, an anion exchange column and a rectifying unit.

Description

The invention relates to a method and apparatus for the regeneration of used low-solid mixtures from car radiators and other heat exchange apparatuses such as central heating systems, solar collectors and other equipment used in industrial practice with an emphasis on obtaining recyclable monoethylene glycol or its aqueous solution and environmentally safe removal of additives .

BACKGROUND OF THE INVENTION

The low-setting compound has the task of cooling the cylinders of the automotive engine and thus keeping them at an optimum working temperature, protecting the metal parts of the engine from corrosion and frost.

Low-solid compositions in addition to monoethylene glycol and optionally other glycols such as monopropylene glycol, diethyl glycol and others contain performance enhancing additives such as pH or alkaline buffering agents, anticorrosives, antifoams, antifoams, colorants, dispersants and others. Prior to use, the low-setting mixture is diluted with water to achieve the desired pour point according to the nature of application. In the working mode, the low-setting mixture is subject to different variations, so it is advisable to ensure that it is replaced according to the manufacturer's recommendations, most often at intervals of three years. Due to the elevated temperature and the catalytic action of the metal ions, the components of the low-setting mixture interact with other subsequent reactions, reducing the alkaline reserve value and the pH value. Such a low-setting mixture should be replaced and disposed of by incineration or a sewage treatment plant.

More preferably, the low-setting compositions used are regenerated and the monoethylene glycol obtained can be used to prepare new low-setting compositions or for another purpose.

Ing. Quinn v r. 1997 described reverse osmosis regeneration on a porous hydrophobic polytertalate. only PTFE, followed by distillation so that the distillation residue contains less than 2,5% monoethylene glycol by weight. In patents CS 263246 and CS 185702, regeneration methods are described which use ion exchangers for regeneration after pH adjustment and removal of mechanical impurities.

Disadvantages of the prior art are eliminated by the method of regeneration of the used low-solid mixtures resulting from the organized collection according to the invention.

SUMMARY OF THE INVENTION

Low-solid mixtures from organized collection may be contaminated in various ways. They can be contaminated by mechanical impurities - sand, rust, various sludge coming from the hardness of the water or corrosive reaction products. They may also be formed by the reaction of additives and corrosive fumes or additives and fuel, engine oils, brake fluids and the like. The collected low-setting mixture used must be homogenized after filtering out coarse mechanical impurities. Fine impurities can be separated by sedimentation while simultaneously spreading oily fractions that collect at the surface of the mixture because they have a lower specific gravity and are practically insoluble in the mixture. The clear low-setting layer used is preventively filtered once more and dispensed into an activated carbon device. Here, the chlorine-reactive molecular chlorine is destroyed, heavy metal compounds, macromolecular substances, traces of unseparated oils, including silicone oils, and colored substances and dyes present, which can be visually indicated to penetrate, are retained on activated carbon. The presence of these substances in the eluate indicates the need to replace or regenerate the cartridge. Further, only water, monoethylene glycol and substances having the nature of salts, predominantly sodium salts, proceed in the process.

Currently, practically three types of low-solid mixtures are used. The first type, a mixture used to cool engines mainly based on ferrous metals, contains the main ingredients sodium 2-mercaptobenzenithiolate and triethanolamine partly in the form of a phosphate salt in addition to other additives improving performance. A second type of composition suitable for aluminum alloy engines comprises a raw material component to prevent corrosion thereof, a salt of the silica stabilized against falling out of the mixture solutions, and also containing a certain proportion of sodium salts of monocarboxylic and dicarboxylic acids. The third type, a mixture having universal use, is designed on the basis of three components which can meet the most demanding requirements, namely the sodium salts of benztriazole derivatives of sodium salts of monocarboxylic acids C8-C12 and alpha, omega-dicarboxylic acids in the form of disodium salts. The share of the third type will increase in the future.

The low-setting mixture further passes through a strongly acidic cation exchanger layer from bottom to top, exchanging cations of dissolved salts to form the corresponding acids in solution, except for free alpha, omega-dicarboxylic acids, which are secreted as voluminous, hydrated flakes, rarely carrying cation exchange particles. should be mechanically separated and returned to the process. The mixture of liquid and flakes after separation proceeds further to contact with the strongly basic anion exchange resin. The solubility of alpha, omega-dicarboxylic acid disodium salts in aqueous monoethylene glycol solution is high, the solubility of free alpha, omega-dicarboxylic acids is about 0.1g / l, and is of such purity that it can be reused to prepare the additive in a new low-setting mixture. which at its price is very lucrative and significantly improves the economy of the process and last but not least increases the capacity of the strongly basic anion exchange resin.

The solution thus treated is contacted with a strongly basic anion exchange resin which binds the remaining portion of the salts from the free acids to form water. Weak acids such as carbonic acid and silicic acid bind the weakest, the penetration of which indicates the depletion of the capacity of a strongly basic anion exchange resin. Acids formed from nitrates and alkaline nitrites decompose to form nitrogen oxides. These can accumulate in dead areas and must be periodically forgiven and disposed of.

The last gas residues dissolved in the mixture to be treated are removed by contact with activated carbon, resulting in a solution of monoethylene glycol in water.

This solution, after the addition of the required amount of monoethylene glycol and the necessary additives, is in fact a diluted low-setting mixture ready for its own application to the vehicle cooling system or for other uses.

It is also possible to separate the monoethylene glycol solution in water into the components by distillation or rectification, preferably under reduced pressure.

The spent cartridges of strongly acidic cation exchanger and strongly basic anion exchanger are recovered after washing and washing off the residues of the processed low-setting mixture according to the manufacturer's recommendation.

The monoethylene glycol recovery device consists of a feed pump connected to a sedimentator connected to a centrifuge and through a filter to the filtrate reservoir. Through the metering device, this filtrate is blown into an activated carbon inlet column which is terminated by a bleached liquid filter leading to the bottom of a cation exchange column terminated with an alpha, omega-dicarboxylic acid filter connected to a cation-exchange liquid reservoir. From there through an anion exchange column metering pump to an anion exchange column and through an activated carbon exit column equipped with a degassed liquid filter to the monoethylene glycol reservoir. The monoethylene glycol solution may be collected for further processing or metered into a reboiler connected to a distillation tank and a column equipped with a condenser, vacuum tank, freezer and vacuum pump. The device also includes an intermediate fraction reservoir, a monoethylene glycol reservoir and a distilled water reservoir.

The main benefit of the method and apparatus for regenerating the low-solid compositions of the present invention is the ability to treat low-solid waste waste compositions based on monoethylene glycol. It is possible to obtain an aqueous solution of monoethylene glycol which, after concentration and / or addition of a further proportion of monoethylene glycol and additives, yields a low-solidification mixture with a pour point of about -40 ° C. The distillation or rectification-obtained monoethylene glycol in a separate installation is not as economically lucrative because of the relatively high energy demand. More preferably, the purified monoethylene glycol solution on an industrial unit is added to the reaction mixture stream coming from the reactor where it is formed from ethylene oxide and water. This stream contains approximately 15 wt. ethylene glycols and directly enters the dewatering column system. The concentration of monoethylene glycol in the recovered aqueous solution is almost always higher and the concentration in a large production unit is economical, and the quality of the resulting product will in no way be adversely affected.

The method of regenerating the low-solid compositions of the present invention will allow for the ecologically advantageous disposal of all of the resulting waste processes at the wastewater treatment plant or incinerator. Packaging containing the low-setting mixture used may be circulated in the process and, if necessary, may be removed from the facility before being shipped for collection or disposal.

The individual apparatuses or aggregates thereof may also be used for other purposes, in particular for the disposal of other organic waste liquids having the character of aqueous solutions, as well as some organic liquids. Clearly, it is possible to produce softened or high-quality dcminalized water with a specific electrolytic conductivity of less than 2 pS / cm on the apparatus of the invention.

The solid wastes resulting from the process of the present invention after removal of the liquid fractions can be disposed of in a waste incineration plant under a flue gas incineration and treatment regime which assumes the presence of metal compounds such as lead, tin, aluminum, magnesium, copper, iron, molybdenum, tungsten. , zinc and other materials derived from construction materials.

Liquid wastes in the form of aqueous solutions mainly contain compounds of sodium, chlorine, carbon, phosphorus, nitrogen, sulfur and other elements. They are diluted with regeneration and rinsing waters. Ideally, such a dilution would guarantee a solubility of less than 2000 mg / l, a monoethylene glycol content of less than 500 mg / l, while respecting a pH requirement of near 7. Any small amount of nitrogen oxides released in the anion exchange column should be decontaminated aqueous lye solution.

The process is energy efficient. Excluding the recovery of pure monoethylene glycol with a concentration of more than 99.5% by distillation, the described process requires only the drive of pumps and centrifuges - an alternative is to use hydrostatic pressure.

Of the construction materials, borosilicate glass, polyethylene, polypropylene, polyvinyl chloride and rubber are suitable for the apparatus.

A conductivity meter, pH meter, water meter and rotameter, a safety valve and a refractometer for monoethylene glycol monitoring should be provided to control and control the processes from the instrument park.

The collection quality of the low-setting mixture used can seriously affect the success of the regeneration operation. Where possible, undiluted liquids free of mineral oils, polychlorinated biphenyls and other foreign substances should be collected.

The apparatus for regenerating the low-solid compositions shown in FIG. First

A raw material inlet is connected to suck in the feed pump 1 using the low-setting mixture. The discharge of the feed pump 1 flows into the sedimentator 2. Next, a cation exchange column 9, a cation exchange liquid tank 10, anion exchange column 14, anion exchange column feed pump 13, anion exchange liquid storage tank 15, a centrifuge 3, distilled water tank 29 and drum and container cleaner 33 The discharge of the feed pump 1 flows into the sedimentator 2. The sedimentator 2 is connected to the discharge of the feed pump 1, a centrifuge 3 and a filter 4, which is connected to the suction of the feed pump 1 and the outlet to the incinerator. The filter 4 is connected to the sedimentator 2, the filtrate reservoir 5 and the outlet to the incinerator. The filtrate reservoir 5 is connected to the filter 4 and the suction of the filtrate dosing pump 6, which is connected to the bottom of the inlet charcoal column 7 and further to the bleached liquid filter 8. The filter 8 is connected to the incinerator outlet and the bottom of the cation exchange column 9, the cation exchange fluid reservoir 10, the waste water reservoir 30, the measuring cup 31 of the hydrochloric acid solution and the filter 11 alpha, omega-dicarboxylic acids with outlet for further purification and / or drying further coupled to a cation exchange liquid container 12, an anion exchange liquid intermediate tank 15, a waste water tank 30 and an anion exchange column 14. This column 14 is connected to an alpha 11 filter, an omega-dicarbocoxylic acid, an anion exchange liquid feed pump 13, an anion exchange liquid intermediate tank 15, a sodium hydroxide solution measuring cup 32 and an activated carbon outlet column 16, a waste water reservoir 30 and feedstock pump. The activated carbon outlet column 16 is connected to an anion exchange column 3, the degassed liquid storage tank 18 and the degassed liquid filter 17 are connected to the incinerator outlet and the monoethylene glycol solution reservoir 19 with the possibility of offtake for further processing or transport to reboiler 20. with a monoethylene glycol solution reservoir 19, a distillation residue reservoir 21 and connected to the column 22 and an intermediate fraction reservoir 27. Connected to the column 22 are a cooler 23, a vacuum reservoir 24, a freezer 25, and a vacuum pump 26 with degassing to the atmosphere. The cooler 23 is connected to the column 22, the water distribution, the intermediate fraction reservoir 27 connected to the reboiler 20, the monoethylene glycol reservoir 28 and the distilled water reservoir 29. The water distribution after passing through the cooler 23 flows into the waste water tank 30. The distilled water reservoir 29 is connected to a waste water reservoir 30 with a water purifier outlet and by pipeline connection to a sodium hydroxide solution measuring cup 32, a hydrochloric acid measuring cup 31, a raw material pump 1 and a drum and container purifier 33 connected to the raw material pump 1.

The device according to the invention operates as follows:

The feedstock, together with the return streams from the individual apparatuses, is conveyed by the feedstock pump 1 to the sedimentator 2, where it is clarified by separating the oily impurities in the upper part and the solid impurities in the lower part. the liquid phase is recirculated. By laterally collecting the clarified liquid through the filter 4, the filtrate reservoir 5 is filled, and the filtrate dosing pump 6 is fed to the inlet charcoal column 7 from which the bleached, treated feedstock or entrained activated carbon particles are collected in the bleached liquid filter 8. Further, the liquid enters from below into the cation exchange column 9, which operates in the buoyant mode, absorbing cations from the salts. Sodium salts of alpha, omega-dicarboxylic acids, low-solid constituents, release alpha, omegadicarboxylic acids very sparingly soluble in the polar environment, and pass through the diffuser nozzles of the cation-exchange column 9 as the flakes pass into the loose upper part. 11 alpha, omegadicarboxylic acids. Sometimes these flakes are difficult to come out with diffuser nozzles, they need to be assisted by the appropriate choice of slot or by the production of hydraulic shocks. The filter 11 may be replaced by a suitably selected tangential separator having an overflow container with the option of draining a solid phase with a portion of the liquid to the centrifuge 3. The clear liquid flows through the bottom into an anion exchange column 14 where salt anions are collected and subsequently into the output charcoal effluent column. through the degassed liquid filter 17 into the monoethylene glycol solution reservoir 19, either for further processing or sucked into the reboiler 20 under reduced pressure. Rectification in column 22 separates under two different vacuum values into the water collected in the distilled water reservoir 29 and the monoethylene glycol stored in the reservoir. 28 of the monoethylene glycol, the intermediate fraction from the intermediate fraction reservoir 27 returns to the reed 20.

Regeneration should be stopped when an increase in the specific electrolytic conductivity, typically 50 pS / cm, is measured at the outlet of the anion exchange column 14.

DETAILED DESCRIPTION OF THE INVENTION

Example 1:

The low-setting mixture diluted 1: 1 by volume was used in military technology for three years. The sample after standing for 10 days in a 200 liter drum was clear and contained: monoethylene glycol, water, borax, triethanolamine, phosphoric acid, 2-mercaptobenzotriazole, benztriazole, sodium nitrate, sodium nitrite and a yellow dye. The monoethylene glycol content was 47.03% by weight. (GLC), water 49.8 wt%, (Karol Fischer), alkaline reserve 4.59 ml 0.1M hydrochloric acid, residue (200 ° C) 2.48 wt%, pour point - 50 ° C, specific weight 1072.8 kg / mť, pH8.12 and refractive index n ²⁰ 1.3860, ash content 0.57% by weight.

A sample of the low-setting mixture described in the previous paragraph was processed on a modeling apparatus arranged as shown in the figure to meet the intended objectives using the essential parts of the apparatus.

Both activated carbon columns were 60 cm long with an inner diameter of 3 cm, made of Simax glass at the bottom equipped with a molten phthite as a false bottom, sealed with a 95% vol. Glass wool pad, filled with activated carbon with a particle size of 0.5 to 1.4 mm with a specific surface area of 900 mm ² / g and an iodine sorption of more than 1000 mg iodine / g.

A cation exchange column identical to the above except that a 0.2 mm stainless steel sieve and a hydraulic shock generating device were mounted at the top to push out the alpha, omega-dicarboxylic acids.

The filter after the column was in some cases replaced by a tangential separator with an overflow tank.

250 ml of strongly acidic cation exchanger based on crosslinked polystyrene with functional sulfo groups bonded directly to the aromatic core in the form of monospheric type beads, density 1.29 g / ml and min. 2.0 eq / l in H ⁺ form with a recommended flow rate of 2000 ml / h, LEWATIT S 100BG, manufactured by BAYER AG.

The anion exchange column was identical in size to the previous column, but without the device for inducing hydraulic shock. The charge consisted of a strongly basic type I anion exchanger, based on a styrene-divinylbenzene copolymer with a trimethylamine functional group in the form of 1.04 g / l monospheric type beads having a capacity of min. 1.3 eq / L for Cl 'form that was in OH' form.

The rectification apparatus of 60 cm length, 3 cm diameter was evacuated equipped with an internal silver-plated double casing with a full-length transparent tape, a dilation spiral, a Rasching rings filling of 4.5 x 4.5 mm and a 3 mm diameter PTFE tube with a cylindrical reed volume 1450 ml, dosing of the cooker with 1000 ml measuring cylinder, mixing by magnetic PTFE body, glass head with complete condensation of vapors. Operating mode for distilling off 13 kPa of water at a boiling point of 51.6 ° C and distilling monoethylene glycol of 1.3 kPa at a boiling point of 91.4 ° C.

The device also included a conductometer with a range of 0 pS / cm to 2000 pS / cm in four partial ranges, a pH meter with a range of 0-14, pressure gauges with a range of 200 to 0.001 TORR, a Votoček vacuum regulator and a rotary oil two-stage vacuum pump. m ³ / hour This laboratory model apparatus was conceived as a verification unit in a ratio of 1: 128, the results could be recalculated to a device with an output of about 300 l / h.

According to the process described in the present invention, 1200 ml / h was dosed. In order to achieve a conductivity of 50 pS / cm, 3900 ml of a 48% by weight aqueous solution of monoethylene glycol, an aqueous solution of monoethylene glycol, was passed through the apparatus.

Rectification according to the above conditions yielded a monoethylene glycol with a water content of 0.25% in a yield of 97.5%.

Example 2:

The low-setting collection mixture consisting of the diluted low-setting mixtures used and samples from laboratory tests was sedimented for 3 days in a steel barrel. The clear liquid consisted of monoethylene glycol, water, triethanolamine, phosphoric acid, sodium α-mercaptobenzithiazoleate, sodium benzoate, borax, sodium nitrate, yellow and green dye, dimethylsiloxane oil, denatorium benzonate, sodium derivatives of bentriazole, sodium bentriazole, sodium bentriazole, acids in the form of sodium salts, sodium polyacrylates and sodium hydroxide.

Based on the analyzes, the monoethylene glycol content was determined to be 39.95 wt%, the water content was 54.70 wt%, the ash content was 0.75 wt%, the specific gravity was 1068.9 kg / m ³ at 20 ° C, the refractive index n ²⁰ 1.3811 at 20 ° C, pH 8.10 at 20 ° C, kinematic viscosity 3.356 mm ² / s at 20 ° C, pour point - 39 ° C, boiling point 107 ° C, residue 3.14 wt. and an alkaline reserve of 8.82 mL 0.1 M HCl, color green.

The low-setting mixture was worked up on the apparatus described in Example 1.

1000 parts by weight of the raw material described were processed. By sedimentation, 5 wt. 10 parts by weight of solid waste were separated by solid phase separation after contact with the cation exchanger. parts of sebacic acid. After passing through the second activated carbon column, 950.3 wt. % by weight of water at a concentration of 42.9 wt. applicable after treatment to produce a low-setting mixture.

By distillation of this solution, as in Example 1, a monoethylene glycol having a water content of 0.2% by weight is obtained. In a yield of 98 wt.

Example 3:

A device as in Example 2 wherein the filter at position 11 has been replaced by a tangential trap.

Industrial usability

The invention will be used as an environmental technology in the field of waste treatment.

PATENT CLAIMS

Claims (3)

Method for the regeneration of low-setting mixtures, characterized in that the solids are removed from the used low-setting mixture by sedimentation, the oily fraction is separated, the solution of the used low-setting mixture is contacted with activated carbon and a strongly acidic cation exchanger, mechanically separated solids are separated. alpha, omega-dicarboxylic acids, the solution is further contacted with a strongly basic anion exchange resin and activated carbon followed by separation of the mixture by distillation or rectification into water and monoethylene glycol. Device for carrying out the method according to claim 1, characterized in that it consists of a feed pump (1) connected to a sedimentator (2), which is connected to a centrifuge (3) and through a filter (4) to a filtrate reservoir (5) and filtrate dosing pump (6) for the activated carbon inlet column (7), which is provided with a filter (8) of bleached liquid entering the bottom of the column (9) with a cation exchanger-terminated filter (11), alpha, omega-dicarboxylic acids (12) cation exchange liquid, further through an anion exchange column (14) with anion exchange column (14) through an activated carbon outlet column (16) equipped with a degassed liquid filter (17) into a monoethylene glycol solution reservoir (19), further into a reboiler (20) connected to a distillation residue tank (21) and connected to a column (22) equipped with a condenser (23), a vacuum container (24), a freezer (25) and a vacuum pump (26) as well as an intermediate fraction container (27), a monoe container (28) and a reservoir (29) of distilled water. Apparatus as described in claim 2, characterized in that a tangential separator is used to separate the alpha, omega-dicarboxylic acids from the feedstock stream.