RU1801029C - Method for separating byproducts and waste in metallurgical industry - Google Patents

Abstract

Use: for cleaning oils contaminated by mechanical impurities, for separating sludge from pulp thickeners from metallurgical and metal processing plants into water, oil and scale. SUMMARY OF THE INVENTION: A method for separating by-products and wastes from the metallurgical industry, for example, oil wastes and sludges or thickened pulps containing water, oil and a solid product, includes the step of distilling off water by heating and separating the mixture into separate components. Water is distilled off at a temperature of the adsorbed water, and then the dehydrated suspension in countercurrent mode is liquefied and the condensed solid is washed with solvents. In order to obtain a solid product in a free-flowing state, the solvent is removed from the wetted sludge by heating the sludge to a temperature of 10-20 ° C above the boiling point of the solvent. 1 s.p. crystals, 2 tablets, 1 ill. fe

Description

The invention relates to the metallurgical industry and can be used for treating contaminated oils, for separating sludge from pulp thickeners of metallurgical and metal processing plants into water, oil and scale.

The purpose of the invention is to simplify technology, improve the quality of stripping products and ensure their reuse, and increase plant productivity.

This goal is achieved by the fact that in the separation of by-products and waste from the metallurgical industry, for example, oil waste and sludge or condensed pulp containing water, oil and a solid product, including the stage of distillation of water during heating and separation of the mixture into separate components, the soda is distilled off at temperatures separating adsorbed water, and then the dehydrated mixture in the mode. countercurrently liquefy and wash the condensed solid product with a solvent, and remove the solvent from the moistened sludge is produced by heating the sludge to tempe00

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10-20 ° C above the boiling point of the solvent.

A method for separating by-products and wastes of the metallurgical industry containing water, oil and a solid product can be used for mixtures containing,%: water 0-80, oil 5-98, scale 0.2-95.

The method is carried out as follows and is illustrated by the flow diagram shown in the drawing. The initial finely dispersed and water-oily sludge (TBSS) is fed to the evaporator reactor 1, in which the complete removal of water is carried out at 145-148 ° C-temperatures of removal of adsorbed water. The suspension is heated with hot flue gases.

The dehydrated sludge enters a threefold, countercurrent washing with an organic solvent in thickeners-washers 2, 3 and 4.

The distilled water in the form of steam condensate is used to maintain the temperature in the thickeners x-washers 2, 3 and 4 at a level of 100-60 ° C, and then is discharged into the water supply system of the rolling mill.

The organic solvent is fed into the thickener-washer 4 from the tank 5 and gravity-washers 3 and 2 are passed by gravity sequentially, enriched with oil fractions extracted from the sludge. The thickened and partially solvent-washed sludge from the washer 2 is fed into the washers 3 and 4 by screw elevators 6 and 7 for countercurrent washing of the sludge from the oils with a solvent.

The sludge washed from petroleum products from the thickener-washer 4 with up to 8% moisture content of the solvent is fed by the screw elevator 8 to the screw dryer 9, where the final drying of the scale from the solvent is carried out. The solvent vapor from the dryer 9 is sent for condensation to the heat exchanger 10. The condensed solvent is collected in the receiving tank 5. The scale is dried by hot flue gases. Dry scale from the dryer 9 is collected in a scale bin 11 where it cools and the solvent is finally degassed. Scale is discharged from the hopper into the truck to the consumer.

The oily solvent from the thickener-washer 2 by gravity passes the heat exchanger 12, heats in it, and then enters the evaporator 13. where the solvent is distilled off from the oils at temperatures 10-20 ° C higher than the boiling points of the solvents. The solvent vapor is condensed in the heat exchanger 10, the condensate is collected in a container 5, from where the solvent again enters the regeneration process.

VAT residue - a mixture of mineral, industrial, technical oils used in rolling production, is removed from the evaporator to a receiving tank

0 14 oils, from where it is sent for reuse in the rolling industry.

The installation is technologically closed.

5 Flue gases as a heat carrier pass through heat-exchange shirts and coils of the following apparatuses: dryers 9 of scale, evaporator 13 of solvent, heat exchanger 12, evaporator 1 of water, after

0 of this is used to heat water for technical and sanitary purposes.

Hydrocarbon solvents are used to liquefy and wash the oily suspension of scale from oils.

5 fractional distillation of oil or coking of coal, having a viscosity of not more than 0.9 m Pa s at 15-20 ° С, density not more than 0.9 g / cm, boiling point and end temperature, at atmospheric pressure, 100-2рО ° S

0 restriction on MPC p, s. not less than 50 mg / m3.

Use as solvents of products of distillation of oil and coking coal instead of synthesized

5 solvents are determined by their availability, prevalence, relatively low cost and, most importantly, the possibility of contamination of bottled oils (technical) with chemical substances not characteristic of them, such as F (fluorine), CI (chlorine) and their compounds, is excluded. Oils using these solvents during distillation are obtained in a conditioned form.

5 The use of solvents with higher viscosity and density indices is impractical due to a sharp decrease in the rate of deposition of scale particles in a suspension of a solvent - TSS

0 (TZH - finely dispersed oily sludge) with a ratio (May) of TZH and solvent equal to 2: 1, which will lead to a significant increase in the area (size) of thickeners (decrease in the productivity of filters and centrifuges) or when the ratio TSS and solvent in the direction of increasing the mass of the solvent to the involvement in the circulation of additional quantities of an intermediate working medium and, as a result, to an increase in the energy consumption for heating solutions, transporting the suspension, for the regeneration of solvents, etc.

The lower limit of the boiling point (n.c. - the boiling point of the boiling point) indicates a high volatility of the solvent, and the smaller it is, the more vapors it contains in the surrounding working area, the greater the likelihood of reaching the CPV thresholds in the working area, poisoning by the vapor serving personnel, solvent losses to the environment, etc.

The upper limit of the boiling point limitation (since the end boiling point) is determined by the conditions for the complete isolation of solvents from oils having a boiling point of 350 ° C.

Limit on MPC not less than 50 mg / m3 indicates a relatively satisfactory harmlessness of the applied solvent to the environment and humans; solvents with lower MPC restrictions are environmentally hazardous.

The principal difference of the proposed method is the introduction of solvents into the oily suspension after separation from the initial water-oily suspension of water. This action significantly affects the improvement of the quality of secreted (regenerated pyeJMbix) products; sedimentation rate (performance of sedimentation tanks, filters, centrifuges) of solid materials from oils and its solutions with organic solvents. The following are the results of an experimental verification of the main stages of the separation of TBZS in comparison with the analogue (application of France) and the prototype.

The main stages include:

1. Evaporation of water.

2. Gravitational isolation of solid and decantation selection of the liquid phase,. 3. The regeneration of the solvent and the production of oils in a conditional form,

4. Obtaining scale in bulk form.

Examples of experimental verification of the main stages of the process.

1. Evaporation of water.

They were carried out in a metal cup with an inner diameter of 97 mm and a height of 290 mm, equipped with a mechanical stirrer, an automatic system for maintaining the set temperature of water stripping, a system for removing water vapor and condensation thereof.

Separation was subjected to TVZSh composition. %: 26.6 - 60 Н20, 29.9 - 25.0 oils: 43.5 - 15 dross.

1.1. According to the method described in the application 1

5 of France No. 2483247,

TVZSh was mixed with a white spirit solvent or coal - solvent in the ratio by weight of TVZSh: solvent 2: 1. At a glass wall temperature of 229 ° С and vigorous stirring, water was distilled off. Solvents are found in the condensate at boiling point temperatures (145 - 148 ° C) (boiling point 1405-200 ° C; s.c. - 120-190 ° C). After stratification, oil products were found in water; when adding white spirit 1.2 g / l; when adding solvent - coal - 3.5 g / l

0 1.2. By the method described in A.S. No. 778739, water was removed by means of a TBZSH heater through a wall (station 229 °), the suspension was stirred vigorously with a stirrer. Completed the distillation of water at

5 120 ° C. The degree of distillation of water reaches 97%. 3% of the water remains in the oil. The oil content in the water ranges from 0.020-0.025 g / l,

01.3. According to the proposed method. Water was removed, as in 1.2., But the distillation of water was completed at 145-148 ° С. The degree of distillation of water in the indicated temperature range is 100%. Oil content in water

5 is maintained at 0.02-0.025 g / l.

2. The deposition of scale in oil and in solvent-oil solutions was carried out in a glass thermostatic cylinder 0 vn. 60 mm and a height of 300 mm. Kinetics

0 deposition was recorded visually.

2.1. According to the method described in the application of France No. 2483247. Precipitation in solution, the solvent is oil, in the ratio of (wt.) TSS and solvent 1: 1.32; at 20 ° C, the initial sedimentation rate of the dross particles upon addition of the solvent was 0.009 mm / s; at 120 ° C. white spirit solvent 0.021 mm / s.

0 2.2. By the method described in A.S. No. 778739, the deposition in oil at 20 ° C of the deposition of scale particles is practically not observed: at 120 ° C the initial rate of deposition of scale particles is

5 0.0042 mm / s.

2.3. According to the proposed method, washing was carried out stepwise.

At each stage, I observe an equal mass ratio between the TSS and the solvent 2: 1, when washing with solvent at

20 ° С the rate of deposition of particles of scale was, mm / s

for the 1st wash 0.019 for the 2nd wash 0.070 for the 3rd wash 0.076 When washing with white spirit at 120 ° C, the rate of deposition of scale particles was, mm / s:

for the 1st wash; 0.043 for the 2nd wash; 0.140 for the 3rd wash; 0.160 3. The quality of the oil and scale. After gravitational compaction of the sludge scale in the cylinder, decantation of oils and solvent-oil was carried out from the sediment,

The solvent – oil liquid system was subjected to thermal distillation, completing the distillation of solvents at 145–150 ° С. The thickened solid precipitate was subjected to natural drying in air and heat drying at 180 ° C.

In the table. 1 shows data on the content of impurities in the product obtained in various ways,

The oil obtained by the proposed method corresponds to a mixture of oils of the grades MS-14 and TC-14.5 and is characterized by the following physical and mechanical values: aux. - 190 ° C; kinematic viscosity at 50 ° C 12.8; at 100 ° С 16.73 eats; acid number 2.22. It can be reused in the rolling industry.

Dross obtained in bulk form. In the table. Figure 2 shows data on the rate of deposition of solid particles (scale) from finely divided oily sludge (TSS) in various media.

Precipitation of fine particles in dehydrated oil at 20 ° C is practically non-existent; in warmed oil up to 120 ° C, the observed particle deposition rate is 0.0042 mm / s. However, complete precipitation of particles at the indicated temperature was not observed even for 12 hours. Up to 30% of the oil remained in the thickened scale. For the separation of oils and scale in conditioned water by the specified method, an additional stage of separation of the suspension is required - vacuum drying at 400 ° C, which greatly complicates the separation process, making it periodic, inefficient and energy-intensive.

The low speed performance of the method of the application of France.

The separation of suspensions into solid (scale) and liquid (oils in solvents) phases with high speed occurs according to the proposed method when adding to dehydrated, oil-lubricated sludge

scale of solvents: solvent - coal (SC) or white spirit (UK). In order to ensure a good washing of the scale from the oils, it is recommended to carry out a three-time countercurrent washing of the thickened sludge with a solvent.

The use of solvents for the separation of TBZSH according to the proposed method minimally pollutes the released water

0 organic substances from the implementation of the process of separation of TBZS according to a known method (French application No. 2483247). In the table. 3 shows the content of organic impurities in the water extracted from

5 TVZSh methods of thermal distillation,

From the table. 3 shows that the content of organic impurities in the water distilled from TVZSh in the absence of solvents according to the known. according to the method (a, p. No. 778738) and the proposed method is 20-25 mg / m3. However, by a known method, water from the TSS is not completely removed. This adversely affects the rate of deposition of solid particles of scale from the water emulsion in oil. According to the proposed method, water is completely removed.

When water is removed from TBZS in the presence of solvents (application Fr. fsfe 2483247), U-C and SK are also distilled with solvents, water is separated from the separated condensate by decantation. Depending on the solvent used, 1,200 to

5 3500 mg / m3 of the organic phase, which significantly exceeds the MPN of organic impurities in the circulating water (MPN - 25 mg / kg) .. Thus, the use of the method of liquefaction of finely divided oily

0 suspensions (TSS) with solvents according to the proposed method gives a new positive effect: it simplifies the separation of finely dispersed water-oiled sludge, improves the quality of separation products (H20: oils; solids), ensures their reuse, increases plant productivity, the solid product is obtained in bulk form.

Claims (2)

0 Claims 1, A method for separating by-products and wastes of the metallurgical industry, mainly oil waste, sludge or condensed pulp, containing 5 water, oil and a solid product, comprising the step of distilling off water during heating and separation of the mixture into separate components, characterized in that, in order to simplify the technology To improve the quality of separation products and to ensure their reuse, to increase the productivity of the plant, water is distilled off at the temperature of adsorption of adsorbed water, and then dehydrated ennuyu suspension was subjected to countercurrent washing of condensed fluidization and solid solvents. 2. The method according to claim 1, characterized in that to obtain a solid product in a free-flowing state, the removal of solvent from the wetted sludge is carried out by heating the sludge to a temperature of 10-20 ° C above the boiling point of the solvent.  UC g white spirit SK - solvent coal Table 1 table 2 Table 3