RU2535699C1 - Method of recycling oily wastes - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: recycling method includes mixing oily wastes with decontaminating components, one of which is unslaked lime (calcium oxide) and adding water which reacts with the unslaked lime, the amount of which is determined based on water contained in the oily wastes. The second decontaminating component used is filter and absorption spent substances which are wastes from the oil and fat industry, obtained at the freezing out step of the process of refining vegetable oil. The method first includes mixing oily wastes preheated to 60-70°C with oil and fat industry wastes in ratio of 1:(0.2-0.4), then, while stirring, adding unslaked lime in portions of 43-83 wt % of the obtained mass to form a homogeneous hydrophobic free-flowing fine powder.

EFFECT: low concentration of harmful substances in the aqueous extract of the recycling product.

2 cl, 1 dwg, 1 tbl, 6 ex

Description

The invention relates to the field of environmental protection, in particular to technological processes for the disposal of oily waste and filter and absorption waste materials when filtering vegetable oil (oil and fat industry waste) and can be used at oil and gas enterprises and waste processing organizations.

A known method of disposal of oil sludge using a "working agent" (US Pat. RF No. 2359982), which consists of quicklime, adsorbent in the form of heat-treated rice husk and triglycerides of higher fatty carboxylic acids. Oil sludge is mixed with a pre-prepared "working agent", adding the required amount of water. A “working agent” consists of calcium oxide, a modifier and an adsorbent. The modifier is triglycerides of higher carboxylic acids in animal fat, which, by hydrolysis, activate the surface of particles with calcium salts of higher carboxylic acids to absorb hydrocarbons and promote hydrophobization of the capsule shell. The adsorbent is used to absorb light hydrocarbon fractions and heavy metals contained in NS.

The disadvantage of the invention is the high content of petroleum products due to insufficient encapsulation of oil sludge. The animal technical fat used for the preparation of the “working agent” is obtained from the waste from the meat processing industry, but during long-term storage it loses its specific properties.

A known method of processing oily sludge using a "working agent" (US Pat. RF No. 2266258), consisting of calcium oxide and a modifier - complete esters of glycerin, vegetable or mineral oils and fat and obtaining a granular product. The "working agent" is mixed with preheated oil sludge to 50-80ºC, with the introduction of an organic thinner in an amount of not more than 5% by weight of oil sludge. For the hydration reaction, the required amount of liquid is added, taking into account the oil sludge contained in it.

The disadvantage of the invention is the high content of petroleum products in the aqueous extract due to insufficient encapsulation of oily sludge.

A known method of disposal of oily sludge (US Pat. RF No. 2395466), taken as a prototype, by obtaining a neutralizing composition and mixing it with oily sludge. The neutralizing composition is obtained by mixing pre-crushed quicklime and spent silica gel - waste gas industry at the stage of drying natural gas for 15-20 minutes. The amount of water required for complete slaking of lime is added to the oily sludge, determined taking into account the sludge present in the sludge and taking into account the water absorption of the spent silica gel. The neutralizing composition is mixed with oily sludge in a ratio of (1.5-2): 1. The product of neutralization is a fine gray-brown powder with a faint odor.

The disadvantage of the invention is the high concentration of harmful substances in the aqueous extract of the recycling product.

The objective of the invention is to develop a new method for the disposal of oily waste of hazard class 3 using more effective available neutralizing components with the properties of a modifier and adsorbent.

Effect: reducing the concentration of harmful substances in the aqueous extract of the recycling product.

The technical result is achieved by mixing oily waste with neutralizing components, one of which is quicklime (calcium oxide) with the introduction of water that reacts with quicklime, the amount of which is determined taking into account the water available in the oily waste. As the second neutralizing component, filter and absorption waste materials are used, which are waste products from the oil and fat industry at the stage of vintization of the process of refining vegetable oil. First, preheated oil-containing wastes are mixed with oil and fat industry wastes in a proportion of 1: (0.2-0.4), then quicklime is added portionwise with stirring in an amount of 43-83% of the mass. from the resulting mass to the formation of a homogeneous hydrophobic granular fine powder. Oil-containing wastes and wastes of the oil and fat industry are mixed, heating to a temperature of 60-70ºC.

Filter and absorption waste materials (hereinafter referred to as waste materials) represent the waste of the oil and fat industry of hazard class 4 (according to the Federal Classification Catalog of Waste), which is formed at the stage of vinification of the process of refining vegetable oil. The waste is formed from a filter diatomaceous powder, which is used to intensify the process of separating wax substances from vegetable oil. After oil purification, pasty waste masses containing wax substances are formed [Refining of oils and fats: Theoretical foundations, practice, technology, equipment. / N.S. Harutyunyan, E.P. Kornena, E.A. Nesterova. - St. Petersburg: GIORD, 2004. - 288 p.]. Wax substances are complex mixtures with a predominant content of plant waxes - esters of high molecular weight fatty acids and monoatomic (less often diatomic) high molecular weight alcohols, carotenoid alcohols (colored waxes). The general formula of waxes is RCOOR ¹ , where R is the hydrocarbon chain of a fatty acid, R ¹ is the hydrocarbon part (chain, cycle or combination thereof) of alcohol. The basis for the release of wax substances is their property to form crystals at low plus temperatures (8-12ºC).

The presence of waxes (high molecular weight esters) with long hydrocarbon chains (from C ₂₂ to C ₃₂ ) of fatty acids and alcohols in the spent masses makes it possible to use the spent masses, both a modifier and a sorbent, due to the silica component in the process of utilizing oily waste. The spent masses contribute to the hydrophobization of the capsule due to the formation of calcium salts during the hydrolysis of esters in an alkaline medium in the presence of calcium hydroxide (equation 1). The structure of the capsule with the hydrophobic shell oil products involved is shown in the drawing.

$$RCOO{R}^{\mathrm{one}}+{\left(CaOH\right)}_2\to {\left(RCOO\right)}_{2}Ca+R^{\mathrm{one}}OH\left(\mathrm{one}\right)$$

The residual sorption properties of the spent masses create the conditions for the absorption of hydrocarbons and heavy metals, since the initial filter powder is obtained on the basis of diatomite (kieselguhr). Chemically, diatomite is more than 80% composed of aqueous silica, which contributes to the formation of a strong calcium silicate structure during the interaction of calcium oxide with silicon dioxide (equation 2) [TU 5761-001-59266087-2005 "Shredded diatomaceous earth]]:

$$CaO+Si{O}_2\to CaSi{O}_3\left(2\right)$$

The method of disposal of waste of hazard class 3 and 4 is carried out by mixing calcium oxide with a mixture of preheated oily waste and waste masses. The waste is mixed by heating to 60-70ºC, and stirred for 5 minutes. At elevated temperatures, the viscosity of the waste decreases due to the transition from a solid to a liquid state of wax substances in the composition of the spent masses and heavy hydrocarbons in the oily waste. Calcium oxide is added in small portions to the mixture of preheated waste with stirring and then water in the amount necessary for the extinguishing of lime, hydrolysis of esters and absorption by the sorbent. The resulting mixture is stirred until a homogeneous free-flowing fine powder is formed. As a result of the exothermic process of quenching calcium oxide, the heated components of the oily waste are drawn into lime capsules to produce a dry hydrophobic powder, each particle of which is coated with a durable water-insoluble shell. Wax substances interacting with calcium hydroxide, hydrolyzing in an alkaline medium, form calcium salts of higher carboxylic acids, which contribute to the hydrophobization of the capsules of the disposal product (equation 1).

The fundamental difference of the invention is the neutralization of oily waste using filter and absorption waste materials that combine both the properties of the sorbent and the modifier. As a result of the process, joint utilization of two types of waste from different industries with the production of environmentally friendly products is ensured. Ecological safety of the disposal product is evidenced by the data on the leachability of harmful substances (BB) in the aquatic environment by the method of quantitative thin layer chromatography (table 1).

Example 1

For research, oil-containing wastes from an oil refinery of the following composition were used: water - 41%, mechanical impurities - 36%, oil products - 23%. The waste contains an excessive amount of water sufficient for the stoichiometric flow of water to extinguish lime, hydrolysis of esters and absorption by the sorbent:

oily waste contains: 50 · 0.41 = 20.5 ml;

to quench calcium oxide according to equation (3) it is necessary:

$$\begin{array}{c}CaO+H_{2}O=Ca{\left(OH\right)}_2+1164\mathrm{to}D\mathrm{well}/\mathrm{to}g\begin{array}{cccc}& & & \end{array}\left(3\right)\\ 56\text{18 74}\end{array}$$

3018/56 = 9.6 ml.

Oily waste and waste masses are mixed in a ratio of 1: 0.4, respectively. 50 g of viscous oily waste and 20 g of waste mass are heated for 5 minutes at a temperature of 60-70ºC. Heated waste is mixed with 30 g of calcium oxide in an amount of 43% of the total weight of the waste mixture. Calcium oxide is added in small portions, stirring vigorously to obtain a homogeneous hydrophobic free-flowing finely divided powder of the product of utilization.

Example 2

The method is carried out analogously to example 1 by heating 50 g of viscous oily waste and 15 g of waste mass in a ratio of 1: 0.3, mixing the mixture with 35 g of calcium oxide in an amount of 54% by weight of the waste mixture.

To quench calcium oxide according to equation (2) it is necessary:

3518/56 = 11.25 ml.

Example 3

The method is carried out analogously to example 1 by heating 50 g of viscous oily waste and 12 g of spent mass in a ratio of 1: 0.24, mixing the mixture with 38 g of calcium oxide in an amount of 61% by weight of the waste mixture.

To quench calcium oxide according to equation (2) it is necessary:

3818/56 = 12.2 ml.

Example 4

The method is carried out analogously to example 1 by heating 50 g of viscous oily waste and 10 g of spent mass in a ratio of 1: 0.2, mixing the mixture with 40 g of calcium oxide in an amount of 66% by weight of the waste mixture.

To quench calcium oxide according to equation (2) it is necessary:

4018/56 = 12.8 ml.

Example 5

The method is carried out analogously to example 1 by heating 50 g of viscous oily waste and 15 g of waste mass in a ratio of 1: 0.3, mixing the mixture with 50 g of calcium oxide in an amount of 77% by weight of the waste mixture.

To quench calcium oxide according to equation (2) it is necessary:

5018/56 = 16 ml.

Example 6

The method is carried out analogously to example 1 by heating 50 g of viscous oily waste and 10 g of waste mass in a ratio of 1: 0.2, mixing the mixture with 50 g of calcium oxide in an amount of 83% by weight of the waste mixture.

To quench calcium oxide according to equation (2) it is necessary:

5018/56 = 16 ml.

The composition of the components for the disposal of oily waste and the concentration of harmful substances in the aqueous extract are presented in table 1.

Table 1 The ratio of components during the disposal of NS and the characteristics of water extracts No. p / p The ratio of oily waste: waste mass Calcium oxide by weight of waste,% The concentration of explosives in an aqueous extract, mg / l one 1: 0.4 43 0.24 2 1: 0.3 54 0.21 3 1: 0.24 61 0.17 four 1: 0.2 66 0.15 5 1: 0.3 77 0.13 6 1: 0.2 83 0.12 7 (prototype US Pat. No. 2395466) 1: 1.5 * 70 0.27 Note: in the prototype, the ratio is 1: 1.5 * - the ratio of oily sludge: neutralizing composition.

As can be seen from table 1, the leachability of the recycling product is less compared to the prototype. The resulting recycling products No. 1-6 are, in each example, a loose hydrophobic fine powder of light gray color, which can be used for construction purposes, for example, for the production of asphalt concrete as an activated mineral powder or for the production of expanded clay as an organomineral additive.

The use of spent masses in recycling technologies will expand the range of affordable and cheap materials based on waste, which will ensure the economic feasibility of the invention.

Claims (2)

1. The method of disposal of oily waste, including mixing oily waste with neutralizing components, one of which is quicklime (calcium oxide), with the introduction of water that reacts with quicklime, the amount of which is determined taking into account the water available in the oily waste, characterized in that as the second neutralizing component, filter and absorption waste materials are used, which are waste products from the oil and fat industry at the stage of vintarization of the process vegetable oil finishes, first, preheated oily wastes are mixed with oil and fat industry wastes in a ratio of 1: (0.2-0.4), then quicklime is added portionwise with stirring in an amount of 43-83 wt.% of the resulting mass until a uniform hydrophobic granular fine powder. 2. The method according to claim 1, characterized in that the oil-containing waste and the oil and fat industry waste are preheated to a temperature of 60-70 ° C.

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