RU2793110C1 - Method of oily waste disposal - Google Patents

Abstract

FIELD: purification of soil from oily waste.

SUBSTANCE: invention can be used in technological processes for the disposal of these wastes by obtaining hydrophobic material from them, such as soil. Simplification of the method of disposal of oily waste, increasing its safety while improving the quality of the resulting product is achieved by the fact that the method of disposal of oily waste obtains hydrophobic material in two stages. At the first stage of obtaining a hydrophobic material, ground limestone is used as a filler, which is added in an amount of 0.6 m³ per 1 m³ of oily waste. Next, the resulting mixture is defended for no more than 8 hours. Add quicklime ground lime in the amount of 0.095 m³ and a 40% solution of sulfuric acid in the amount of 0.0008 m³, mix and incubate the mixture for 12 hours. Next, the second stage of obtaining a hydrophobic material is carried out, when 0.5 m³ of water is added per 1 m³ of the product obtained in the first stage; sand is added in an amount of 0.3-0.5 m³ and hydrophobizing organosilicon liquid in an amount of 0, 0004 m³. Next, Portland slag cement is introduced in an amount of 0.15-0.5 m³, and the resulting material is cured for 20-25 days, while the material is stirred during holding.

EFFECT: method of disposal of oily waste is simplified, its safety is increased while improving the quality of the resulting product.

1 cl, 3 tbl, 1 ex

Description

The invention relates to the field of environmental protection, in particular, to the restoration of contaminated soil and its purification from oily waste, can be used in technological processes for the disposal of these wastes by obtaining hydrophobic material from them, for example, dispersed soil. Applicable in the oil and petrochemical industry, in the reclamation of industrial sites.

A known method for producing a reagent for neutralizing oil and gas industry waste according to the RF patent for invention No. 2527288, B09C 1/08, 2014. The reagent is obtained by mixing quicklime with a water repellent when heated. Moreover, oil and paraffin waste is used as a water repellent, and mixing is carried out at a temperature of 75-120°C in the absence of moisture in the following ratio of components (wt.%): oil and paraffin waste - 5-20%, the rest is quicklime. The disadvantage is the complexity of the method and its insecurity associated with the need to heat oil and paraffin waste and the complexity of controlling the temperature of the process.

There is a known method of isolating oil in the soil by chemical encapsulation according to the patent of the Russian Federation No. 2724456, B09C 1/08, 2020. The process of restoring oil-containing soil with the release of hydrophilic and neutral soil is carried out by adding calcium oxide, an aqueous concentrate of sodium silicate (liquid glass - ZhS) to the soil. Phosphoric acid (H3PO4) is used as the acid agent. The disadvantage is the complexity of the implementation of the method associated with the use of specific and rare neutralizing components such as sodium silicate and phosphoric acid.

A known method for the disposal of oily waste according to the patent of the Russian Federation No. 2538587, A62D 3/33, 2015, which includes mixing oily waste with a neutralizing composition until a homogeneous hydrophobic free-flowing fine powder is formed. The neutralizing composition contains quicklime ground to a finely dispersed state in the amount of 67-91 wt.% and spent silica gel - 9-33 wt.%, which is a waste of the gas preparation plant for transportation. An estimated amount of water is introduced that reacts with quicklime, the required amount of which is determined taking into account the water present in the oily waste and the water absorption of the spent silica gel. Before mixing, oil-containing wastes are mixed by heating to 60-70°C for 5-10 minutes with filtering and absorbing waste masses formed at the stage of winterization of the vegetable oil refining process in a ratio of 1: (0.05-0.2). Then, the neutralizing composition is introduced into the resulting mixture in portions in a ratio of 1: (0.67-1.14) while stirring with a mechanical stirrer at a speed of 100-110 rpm and at an increase in temperature from 99 to 144°C for 10-15 minutes. The disadvantage is the complexity of the method associated with the need for batch introduction of the composition, with heating operations at different stages of obtaining a hydrophobic material. In addition, the concentrations of harmful substances in water extracts from the product, characteristic of oily waste, have not been determined, which does not allow us to conclude that the disposal product is safe.

As the closest analogue to the claimed technical solution, a method for isolating oil in the soil by chemical encapsulation was chosen according to the RF patent for the invention No. 2723182, B09C 1/08, 2019. The method includes the introduction of an emulsifier - calcium stearate (StCa), calcium carbonate (CaCO3) as an alkaline agent and iron sulfate (II) - FeSO4 * 7H2O - as an acid agent in mass ratios 1.0: 0.5: 0.3: 0.85 > Oil : StCa : CaCO3 : FeSO4 * 7H2O ≥ 1, 0:0.3:0.2:0.55. The disadvantage is the need to use a significant amount of specific and rare neutralizing components, such as sodium stearate and ferrous sulfate, which complicates the process of cleaning the soil from oily waste. In addition, the use of combustible sodium stearate requires special measures to ensure process safety. It is necessary to protect people from its chemical effects. It is necessary to take special measures to prevent accidental entry of sodium stearate into sewers, surface and ground waters to avoid adverse environmental impacts.

The technical result of the claimed invention is the simplification of the method of disposal of oily waste, increasing its safety while improving the quality of the resulting product.

The technical result is achieved by the fact that in the method for the disposal of oily waste, including the production of hydrophobic material by mixing oily waste with a filler containing calcium carbonate, according to the invention, at the first stage of obtaining a hydrophobic material, ground limestone is used as a filler, which is added in an amount of 0.6 m ³ per 1 m ³ of oily waste, then the resulting mixture is settled for no more than 8 hours, quicklime ground lime in the amount of 0.095 m ³ and a 40% sulfuric acid solution in the amount of 0.0008 m ³ are added to it, mixed and the mixture is kept for 12 hours , then the second stage of obtaining a hydrophobic material is carried out, on which 0.5 m ³ of water is added per 1 m ³ of the product obtained in the first stage, sand is added in an amount of 0.3 - 0.5 m ³ and hydrophobizing organosilicon liquid in an amount of 0.0004 m ³ , then portland slag cement is introduced in an amount of 0.15 - 0.5 m ³ and the resulting material is kept for 20 to 25 days, the material is mixed during holding

Humidity is 15-40% according to research.

The technical result of improving the quality of the resulting product is ensured by carrying out work to obtain a hydrophobic material - a dispersed soil modified in two stages. This improves the quality of oily waste disposal. The simplification of the disposal method and the improvement of its safety are achieved through the use of accessible and safe components widely used in construction, which do not require special operations for preparation for use and use itself, and do not require additional measures to ensure the safety of their use. Thus, ground limestone introduced at the first stage of work is a mineral powder of sedimentary rock, consisting mainly of calcium carbonate (CaCO3). Its use is safe. Its main purpose in the disposal of oily waste is to transfer bulk oil waste into a thin-film state. Together with liquid oil waste, the mineral powder forms a structured dispersed system, which acts as a binding material in the waste treatment. Quicklime, which is burnt limestone, is a binder that is widely available and widely used in construction. The use of quicklime in the proposed method in the open ventilated space of the industrial area ensures the safety of working with it. For the disposal of oily waste, medium or slow-extinguishing lime is used. To reduce the rate of lime slaking reaction, a 40% solution of sulfuric acid - electrolyte is added. This improves the quality of the resulting product, as it slows down the setting time of lime, eliminates the phenomenon of volume volatility, increases the mechanical strength of the lime frame and reduces the pH value. The electrolyte is added to the waste in conjunction with the filler. Stirring the resulting mixture and holding it for 12 hours make it possible to obtain a dry powder with a moisture content of not more than 5% and an oil content of not more than 15%. This intermediate product complies with specifications and is safe for further use. The subsequent operations of the second stage of work are aimed at improving the quality of the final product - modified dispersed soil. For the production of modified soil, a component composition is used that contains building sand as a filler, Portland slag cement as a binder, hydrophobic organosilicon liquid (GCL) as a technological additive, technical water is used to obtain the required mixture consistency. All components for the modification of dispersed soil are available, widely applicable, and are introduced with conventional mechanical mixing. With the introduction of water, a lime mortar is obtained, containing in its structure particles of sand and limestone, on the surface of which residual oil products are adsorbed in the form of an oil film. With the introduction of a filler in the form of building sand, adsorption and adhesive binding of residual oil products occurs on the developed surface of sand grains. During the process of crystallization of calcium hydroxide, the evaporation of water causes the gradual adhesion of its smallest particles into larger ones and their crystallization. Growing crystals grow together, forming a calcareous framework that surrounds the particles of sand and limestone. Thus, sealing the oil film on the filler particles in a waterproof shell, which helps to improve the quality of the final product. Simultaneously with the sand, a technological additive is introduced into the mixture - a hydrophobizing organosilicon liquid, which is a surfactant. It is necessary both to reduce the amount of binder material and to create a closed microscopic structure that prevents the penetration of water, leaching and migration of associated oil products. The addition of slag-slag cement improves the quality and strength of the lime frame, and converts it into a more stable and insoluble compound, calcium hydrosilicate, and improves the quality of the resulting soil. The optimal amount of components introduced into oily waste has been determined experimentally. For industrial research, 12 initial processed mixtures were prepared, the composition of which is presented in Table 1.

The density of ground lime is 900 - 1100 kg / m ³ , for the convenience of calculations, the density of ground lime is taken - 1000 kg / m ³ , therefore 0.02 - 0.095 tons indicated in table 1 is 0.02 - 0.095 m ³ of ground lime. The density of Portland slag cement is 900 - 1200 kg / m ³ , for the convenience of calculations, the density of Portland slag cement is taken - 1200 kg / m ³ , therefore 0.05 - 0.5 tons indicated in table 1 is 0.042 - 0.42 m ³ of Portland slag cement.

Humidity is 15-40% according to research.

Table 1. Composition of the studied mixtures Mix No. The composition of the mixture per 1 m ³ of oily waste Concentration of oil products in waste, % Mineral powder, m ³ Construction sand, m ³ Ground lime, dolomitic II grade, tons Portland slag cement, tons Sulfuric acid solution, l GKZh, l Technical water, m ³ 1 60 0.6 0.5 0.095 0.5 0.8 0.4 0.5 2 50 0.5 0.5 0.085 0.4 0.7 0.35 0.4 3 40 0.4 0.4 0.075 0.35 0.65 0.3 0.35 4 thirty 0.3 0.3 0.060 0.25 0.5 0.2 0.25 5 20 0.2 0.3 0.045 0.15 0.4 0.15 0.20 6 10 - 0.2 0.035 0.10 0.3 0.1 0.15 7 5 - 0.1 0.025 0.05 0.2 0.05 0.05 8 60 0.5 0.4 0.08 0.4 0.7 0.3 0.4 9 40 0.3 0.4 0.06 0.3 0.6 0.2 0.3 10 thirty 0.2 0.2 0.05 0.2 0.4 0.1 0.2 eleven 20 0.1 0.2 0.035 0.1 0.3 0.1 0.15 12 5 - 0.1 0.02 0.05 0.1 0.03 0.05

Table 2 presents the results of the study of water after contact with the obtained samples of reclamation material.

Table 2. Results of the studied samples Mix No. pH of water extract, units pH Content of oil products, mg/l Phenol content, mg/l 1 6.6 0.009 But 2 6.9 0.008 But 3 7.2 0.006 But 4 7.5 0.008 But 5 7.7 0.007 But 6 8.0 0.009 But 7 8.3 0.008 But 8 5.5 0.016 But. 9 5.9 0.015 But. 10 6.3 0.022 But. eleven 10.1 0.035 But. 12 10.3 0.027 But.

Samples 1-7 are suitable according to the required parameters, while samples 8-12 are not suitable due to the lack of compliance with the pH requirements (at least 6.5-8.5 for surface waters). Thus, the required ranges for the introduction of reagents were determined.

Thus, with the ease of implementation of the proposed method for the disposal of oily waste and ensuring the safety of work with the input components, the composition and quantitative content of the proposed components can improve the quality of the resulting modified dispersed soil.

The method of disposal of oily waste is carried out as follows.

For the disposal of oily waste at the waste accumulation facility, cutting lanes are equipped to cover the largest area of the accumulation facility, based on the depth of the waste, as well as to divide the accumulation facility into a preparation zone, a disposal zone and storage of the intermediate disposal product. They arrange buried sites for disposal work directly in the body of the accumulation object, which in turn eliminates the need to move oily waste throughout the facility and reduces possible environmental risks. Further, jumpers are built between the cutting strips - cutting strips from the sand mixture, as well as cutting strips, cards are made isolated from each other - places for waste disposal. Bases are cemented in the maps to prevent the overflow and migration of contaminated process water used in the recycling process. Oily waste is loaded into the cards from the place of accumulation using a hydraulic excavator. All technological operations are carried out within the boundaries of the sludge collector, which excludes the ingress of waste outside the accumulation object. To reduce the mass fraction of oil products in the waste and to change the state of aggregation of oil-containing waste, the first preliminary stage of work is carried out to obtain a dispersed modified soil suitable for technical reclamation of the sludge reservoir. To do this, mixed in a mechanized way, to a homogeneous, homogeneous mass of oily waste, make a filler - ground limestone, preferably with particles smaller than 0.07 mm. So, if for particles smaller than 07 mm the specific surface is 500 m ² /kg, then the specific surface of the fraction with particle sizes of 0.20 - 0.30 mm is only 30 m ² /kg. Since the porosity of ground limestone is 30-35%, in such powders, filtration of oil products into the depths of the particles is inevitable. Approximate volumes of the filler of various fractions, with additional preparation, per 1 m ³ of waste are presented in table 3.

Table 3. Approximate volumes of filler application per 1 m ³ of waste No. Waste quantity Fraction of filler particles (mm). Filler quantity 1 1m ³ less than 0.07mm 0.20-0.30m ³ 2 1m ³ from 0.07 to 0.09 0.35-0.40m ³ 3 1m ³ from 0.1 to 0.15 0.50 - 0.60m ³ 4 1m ³ over 0.17 up to 1m ³

After thorough mixing and settling for at least four hours at positive temperatures, and at least eight hours at negative temperatures up to -10 ° C, quicklime is added that complies with GOST 9179-2018 "Building lime" "Technical conditions". Calcium, air lime is used, consisting mainly of calcium oxide or hydroxide without impurities of hydraulic or pozzolanic materials, or dolomite lime, consisting of calcium oxide and magnesium oxide or calcium hydroxide and magnesium hydroxide without impurities of hydraulic or pozzolanic materials. Quicklime ground lime is applied without additives. Use medium or slow-extinguishing lime. For 1m³ waste contribute 0.095 m³ lime at its density 1000kg/m³, or 0.095 tons. To reduce the reaction rate of lime slaking, a 40% solution of sulfuric acid (electrolyte) is added, at the rate of 0.5 - 0.8 liters per 1 m³ oily waste. Electrolyte is added to the waste in conjunction with a filler - mineral powder. At the stage of preparation of waste for disposal, at the preliminary stage of work on obtaining a dispersed modified soil, the slaking of the introduced lime is carried out with a small amount of water to obtain a “fluff”. Water, for such quenching, is sufficient in oily waste. After thorough mixing, the mixture is kept for 12 hours. The resulting mass is a dry powder with a moisture content of not more than 5%, and an oil content of not more than 15%. Then proceed to the second stage of work on the disposal of oily waste. The second stage is to improve the quality of the product obtained at the preliminary stage, its result is the production of a dispersed modified soil. For this, 1m³ prepared soil obtained at the first stage, the following component composition is introduced:

- filler - building sand GOST 8637-2014 - 0.3-0.5 m ³ ;

- binder - Portland slag cement - up to 0.15-0.5 tons, or 0.15 - 0.5 m ³ at a density of 1000 kg / m ³ ;

- technological additive - hydrophobic organosilicon liquid (GKZH) 136-157M - 0.4 liters, or 0.0004 m ³ ;

- technical water GOST 23732-2011 - 0.5 m ³ .

The components are added in the following order. Industrial water is introduced into the dry mixture of limestone and slaked lime (fluff) obtained at the first stage of work. The mixture is brought to the state of liquid lime paste by mechanical stirring. After obtaining a homogeneous mixture, a filler is added - construction sand. The amount of filler is associated with the need to give the resulting technogenic soil sufficient permeability, which must correspond to a Kf of at least 5 m/day. This is necessary for the natural drainage of rain and melt water. After thorough mixing, a lime mortar is obtained, which is close in consistency to liquid dough, containing particles of sand and limestone in its structure, on the surface of which residual oil products are adsorbed, in the form of an oil film. As a result of mixing waste, lime paste and filler (construction sand), adsorption and adhesive binding of residual oil products occurs on the developed surface of sand grains. Simultaneously with the sand, a technological additive is added to the mixture - a hydrophobizing organosilicon liquid GKZH-136-157M. Technological additive GKZH-136-157M is necessary both to reduce the amount of binder and to create a closed microscopic structure that prevents the penetration of water, leaching and migration of associated oil products. Next, slag cement of the brand CEM M/V-Sh 32.5N, or CEM M/V-Sh 22.5N is added. Portland slag cement, in addition to the binder, acts as a hydraulic additive. The reaction in this case proceeds only in the presence of water, although the resulting new compound, calcium hydrosilicate, is not soluble in water. After thorough mixing, the finished product of utilization is loaded with a hydraulic excavator and taken to the site for aging for 20-24 days for the final formation of all physical and chemical structures of the product. At the same time, during the aging process, the product is constantly stirred to destroy the film of calcium carbonate formed in the first periods of hardening of lime and cement, and to accelerate the carbonization reaction. The process of transition of calcium hydroxide to a more stable structure, calcium hydrosilicate, proceeds rather slowly. Therefore, the storage time of the disposal product must be at least 20 days at air temperatures above +10°C. With a decrease in temperature for every 5 ° C, the aging period increases by 5 days. As a result of the performed operations, a homogeneous hydrophobic free-flowing fine powder is obtained that is safe for the environment.

Example 1

100 m ³ of oily waste from the place of accumulation were loaded into the maps between the cutting strips using a hydraulic excavator. Laboratory studies were carried out, as a result of which it was found that the mass fraction of oil products in the volume of waste is 52.73%.

In a mechanized way, namely with an excavator, the oil-containing waste was mixed to a homogeneous, homogeneous mass. The mass was settled for 4 hours at a temperature of +15°C and a humidity of 30%. Made ground limestone fraction 0.10mm in the amount of 60m ³ . They introduced 9.5 m ³ of quicklime ground GOST 9179-2018 "Construction lime""Technicalconditions". Made a 40%solution of sulfuric acid 0.08m ³ . The resulting mixture was stirred and kept for 12 hours. Received a dry mixture of prepared waste in the amount of 100m ³ .

Further, technical water was introduced into the prepared waste, corresponding to GOST 23732-2011, in the amount of 50m ³ . By mechanical stirring, the mixture was brought to the state of liquid lime dough. After obtaining a homogeneous mixture, building sand 30m ³ was added, and simultaneously with the sand, a hydrophobizing organosilicon liquid GKZH-136-157M (TU 6-02-694-76) was introduced in an amount of 0.04m ³ . After thorough mixing, a lime mortar was obtained, similar in consistency to liquid dough, into which Portland slag cement CEM II/V-Sh 32.5N was added in an amount of 15 m ³ . The finished product was mixed, taken to the site for aging, the product was kept for 20 days at a temperature of 10-15°. During these 20 days, the resulting soil was mixed with an excavator.

As a result of the performed operations, a homogeneous hydrophobic free-flowing fine powder was obtained, which, in accordance with Table 2, is safe for the environment and does not exceed the content of oil products of 1.5%.

Thus, the claimed invention allows to improve the quality of the resulting product, to simplify the method of disposal of oily waste, to ensure its safety.

Claims (1)

A method for the disposal of oily waste, including the production of a hydrophobic material by mixing oily waste with a filler containing calcium carbonate, characterized in that at the first stage of obtaining a hydrophobic material, ground limestone is used as a filler, which is added in an amount of 0.6 m ³ per 1 m ³ oily waste, then the resulting mixture is settled for no more than 8 hours, quicklime ground lime is added to it in the amount of 0.095 m ³ and a 40% solution of sulfuric acid in the amount of 0.0008 m ³ , mixed and the mixture is kept for 12 hours, then the second stage is carried out obtaining a hydrophobic material, on which 0.5 m ³ of water is added per 1 m ³ of the product obtained in the first stage, sand is added in an amount of 0.3-0.5 m ³ and hydrophobizing organosilicon liquid in an amount of 0.0004 m ³ , then portland slag cement is introduced in the amount of 0.15-0.5 m ³ and the resulting material is held for 20 to 25 days, the material is mixed during holding.