RU2603149C1 - Method for recycling oily wastes - Google Patents

Abstract

FIELD: environmental protection.

SUBSTANCE: invention relates to environmental protection, in particular, to processes of recycling oily wastes, spent silica gel and wastes of oil and fat industry. Oily wastes preliminarily heated up to the temperature of 80-85 °C are mixed with oil and fat industry wastes at a ratio of 1:(0.05-0.2). Portions of decontaminating composition are added while stirring, decontaminating composition containing unslaked lime and spent silica gel ground to fine state at a ratio of 1:(0.125-0.25). Calculated amount of water for reaction with unslaked lime is introduced, required number of unslaked lime being determined based on water available in oily waste and water absorption of spent silica gel. Recycled filter and absorbent waste masses are used as oil and fat industry wastes produced after repeated regeneration of diatomite filtering powder. Decontaminating composition is added to the mixture of wastes at a ratio of 1:(0.75-0.95) until the formation of a homogeneous hydrophobic loose fine powder.

EFFECT: reduced wash out of foreign matters from product of oily waste recycling.

1 cl, 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, spent silica gel (waste from a gas preparation plant for transportation) and recycled filter and absorption waste materials (oil and fat industry wastes), and can be used at oil and gas enterprises and at waste processing enterprises.

A known method of disposal of oily sludge [US Pat. 2395466, publ. 07/27/2010. Bull. No. 21] 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 due to insufficient hydrophobicity of the capsules in the absence of a modifier.

The prototype of the invention is a method for the disposal of oily waste (NSO), including mixing the oily waste with a neutralizing composition (OK) containing powdered quick lime quicklime (calcium oxide) and spent silica gel, which is the waste of the installation for the preparation of gas for transportation, followed by the introduction of the estimated the amount of water for the reaction with quicklime, the required amount of which is determined taking into account the water available in the oily waste, and water absorption permeability of spent silica gel. Before mixing, the oily waste is pre-mixed with heating to 60-70 ° C for 5-10 minutes with filter and absorption waste materials formed at the stage of winterization of the process of refining vegetable oil (waste oil and fat industry) in the ratio 1: (0.05-0 , 2), then the neutralizing composition is introduced portionwise into the resulting mixture in the ratio 1: (0.67-1.14) until a homogeneous hydrophobic free-flowing fine powder is formed [US Pat. 2538587, publ. 01/10/2015. Bull. No. 1].

The disadvantage of the invention is the high leachability of pollutants (pollutants) from the product of the disposal of oily waste using filter and absorption waste materials obtained at the stage of winterization of the process of refining vegetable oil, due to the presence of insufficient wax substances in them. In addition, the oil and fat industry waste used in this invention is a valuable intermediate product containing vegetable oil, which should be further processed rather than recycled.

The objective of the invention is to increase the efficiency of the method of simultaneous utilization of two types of oily waste hazard class 3 while reducing the cost of the method.

The technical result is to reduce the leachability of pollutants (reducing the concentration of pollutants in the aqueous extract) from the product of the disposal of oily waste when using more effective available neutralizing components with the properties of a modifier and adsorbent.

The technical result is achieved by the fact that preheated oily waste is mixed with oil and oil industry wastes, a neutralizing composition containing quicklime, ground to a finely dispersed state, and spent silica gel, which is a waste of the gas preparation unit for transportation, is added portionwise with stirring, followed by introduction calculated amount of water for the reaction with quicklime, the required amount of which is determined taking into account the water Available in the oily waste, waste and water absorption of silica gel. At the same time, oily waste is mixed with oil industry waste in a ratio of 1: (0.05-0.2), recycled filter and absorption waste material obtained after repeated regeneration of diatomaceous filter powder is used as oil industry waste, the neutralizing composition contains finely divided quicklime and spent silica gel in the ratio 1: (0.125-0.25), and the neutralizing composition is added to the waste mixture in the ratio 1: (0.75-0 , 95) until a homogeneous hydrophobic granular fine powder is formed, and the oil-containing waste with the waste of the oil and fat industry is mixed, preheated to a temperature of 80-85 ° C.

Oil sludge is an oil-containing waste of the oil and gas complex and is formed as a result of production activities in the extraction, transportation, storage and processing of oil.

Spent silica gel is a waste of the gas preparation unit for transport at compressor stations.

Recycled spent masses represent the waste of the oil and fat industry of hazard class 4 obtained at the stage of recycling the filter diatomaceous powder used in the process of refining vegetable oil to clean oil from wax substances. Multiple recycling of regenerated filter and absorption waste materials separated from the fat product allows making the process of refining sunflower oil more cost-effective by reducing the consumption of expensive diatomaceous filter powder and more complete desorption of the target fat product.

With multiple regeneration cycles of filter and absorption waste materials, the content of wax substances in them increases from 49 to 80% [Kosulina TP, Tsokur OS, Levashov AS, Lukina D.Yu. Some properties and composition of wastes of the oil and fat industry at the stage of winterization of vegetable oil // Ecological Bulletin of the BSEC Scientific Centers. 2013. No4. S. 67-75], while waxy substances have more pronounced water-repellent properties than fats. When the recycled spent masses are heated to 70 ° C, there is not enough desorption of wax substances from the pores of the diatomaceous powder, which leads to a loss of hydrophobizing properties, and the effectiveness of the modifying additive does not increase, but decreases. Thus, for the use of recycled spent masses as a modifying additive, their more significant heating is required in the process of mixing them with NSO.

The use of a modifying additive with a high content of vegetable waxes (recycled spent masses) in the composition of OK and an increase in temperature at the mixing stage allows the waxes to be desorbed from the diatomaceous filter powder and to exhibit water-repellent properties of the disposal product.

Wax substances are complex mixtures with a predominant content of esters of high molecular weight fatty acids and high molecular weight alcohols. Waxes general formula RCOOR ^1, wherein R - hydrocarbon chain of a fatty acid, R ¹ - hydrocarbon portion of a fatty alcohol (chain, ring or a combination thereof). The presence of acids and alcohols with long hydrocarbon chains (from C ₂₂ to C ₃₂ ) in waxes makes it possible to use defatted and wax-enriched waste masses as a more effective modifier for the disposal of NSOs, which promotes hydrophobization of the capsule with the involved oil products due to the formation of calcium salts of fatty acids and high molecular weight alcohols in reaction with calcium oxide (equation 1):

The residual sorption properties of spent sorbents create the conditions for the absorption of hydrocarbons. When quenching calcium oxide in an alkaline medium, heavy metal ions are converted into insoluble hydroxides (equation 2):

Chemically, diatomite is more than 80% composed of aqueous silica. The use of spent silica gel and silica-containing diatomaceous waste mass contributes to the formation of a strong calcium silicate structure in the interaction of calcium oxide with silicon oxide (equation 3):

A method for the disposal of waste of hazard class 3 and 4 is carried out by adding a neutralizing composition, consisting of quicklime (calcium oxide) and spent silica gel, to a mixture of preheated oily waste and recycled spent masses with stirring, while stirring. The NSO and recycled spent masses are mixed for 5 minutes, heated to 80-85 ° C, the increased temperature condition is necessary to lower the viscosity of the waste and to more fully desorb the wax substances that are part of the recycled spent mass and to completely mix the organic part of the waste with calcium oxide . OK, and then water is added to the mixture of preheated wastes in small portions with stirring in an amount necessary to extinguish the lime, hydrolysis of the 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 when interacting with calcium hydroxide, hydrolyzing in an alkaline medium, form calcium salts of higher carboxylic acids and higher alcohols, which contribute to the hydrophobization of capsules of the recycling product (equation 1).

The principal difference of the present invention is the neutralization of the NSO using recycled waste masses - previously unrecycled wastes from the oil and fat industry of the stage of recycling the refining process of vegetable oil (the prototype used the spent masses of the winterization stage with a single use of filter diatomaceous powder, which today are subject to more efficient processing), as well as increasing the heating temperature of recycled spent masses to 80 -85 ° C when mixing them with NSO for more complete desorption of their constituent wax substances. As a result of the recycling process, three types of waste from different industries are jointly neutralized, which expands the range of neutralizing compositions used for the disposal of NSOs and minimizes the cost of their acquisition. The environmental safety of the disposal product is evidenced by data on the leaching of pollutants into 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 excess amount of water sufficient for the stoichiometric flow of water to extinguish lime and absorption by the sorbent:

oily waste contains: 50 · 0.41 = 20.5 g of water;

taking into account the water absorption of spent silica gel (12%):

12.10.10 = 1.2 g;

To extinguish 40 g of calcium oxide according to equation (4), it is necessary: 40 · 18/56 = 12.9 g of water.

Oil-containing wastes and wastes of the oil and fat industry are mixed in a ratio of 1: 0.2, respectively. At a temperature of 80-85 ° C for 5-10 minutes heated with stirring 50 g of viscous oily waste and 10 g of waste oil and fat industry. The neutralizing composition is obtained by mixing loose components: 40 g of calcium oxide and 10 g of spent silica gel in a ratio of 1: 0.25, respectively. The heated waste mixture is mixed with OK, adding in small portions, in a ratio of 1: 0.83, respectively. The resulting mixture, which is heated in the process of quenching to a temperature of 118 ° C, is intensively mixed until a homogeneous hydrophobic free-flowing fine powder of the product of utilization is obtained. The oily waste used for disposal contains a sufficient amount of water in its composition, so water is not added. However, this method of disposal can be used not only for irrigated oily waste, but also for waste with an insufficient amount of water contained in their composition, to extinguish lime, then process water is added.

Example 2

The method is carried out analogously to example 1, mixing, while heating, 50 g of viscous oil-containing waste and 10 g of oil and fat industry waste in a ratio of 1: 0.2, obtaining OK by mixing 40 g of calcium oxide and 5 g of spent silica gel in a ratio of 1: 0.125, respectively, mixing heated mixtures with OK in a ratio of 1: 0.75. The resulting mixture in the process of quenching is heated to 120 ° C.

To quench calcium oxide according to equation (4) it is necessary:

40 · 18/56 = 12.6 g of water,

taking into account the water absorption of spent silica gel (12%): 5 · 0.12 = 0.6 g.

The necessary amount of water is contained in the oil sludge, additional introduction of water is not required.

Example 3

The method is carried out analogously to example 1, mixing, while heating, 50 g of viscous oil-containing waste and 5 g of oil and fat industry waste in a ratio of 1: 0.1, obtaining OK by mixing 40 g of calcium oxide and 10 g of spent silica gel in a ratio of 1: 0.25, respectively mixing the heated mixture with OK in a ratio of 1: 0.91. The resulting mixture in the process of quenching is heated to 124 ° C.

To quench calcium oxide according to equation (4) it is necessary:

40 · 18/56 = 12.6 g of water,

taking into account the water absorption of spent silica gel (10%): 10 · 0.12 = 1.2 g.

The necessary amount of water is contained in the oil sludge, additional introduction of water is not required.

Example 4

The method is carried out analogously to example 1, mixing, while heating, 50 g of viscous oil-containing waste and 5 g of oil and fat industry waste in a ratio of 1: 0.1, obtaining OK by mixing 40 g of calcium oxide and 5 g of spent silica gel in a ratio of 1: 0.125, respectively, mixing heated mixtures with OK in a ratio of 1: 0.82. The resulting mixture in the process of quenching is heated to 133 ° C.

To quench calcium oxide according to equation (1) it is necessary:

40 · 18/56 = 12.6 g of water,

taking into account the water absorption of spent silica gel (12%): 5 · 0.12 = 0.6 g.

The necessary amount of water is contained in the oil sludge, additional introduction of water is not required.

Example 5

The method is carried out analogously to example 1, mixing, while heating, 50 g of viscous oily waste and 2.5 g of oil and fat industry waste in a ratio of 1: 0.05, obtaining OK by mixing 40 g of calcium oxide and 10 g of spent silica gel in a ratio of 1: 0.25 accordingly, mixing the heated mixture with OK in a ratio of 1: 0.95. The resulting mixture in the process of quenching is heated to 138 ° C.

To quench calcium oxide according to equation (1) it is necessary:

40 · 18/56 = 12.6 g of water,

taking into account the water absorption of spent silica gel (12%): 10 · 0.12 = 1.2 g.

The necessary amount of water is contained in the oil sludge, additional introduction of water is not required.

Example 6

The method is carried out analogously to example 1, mixing, while heating, 50 g of viscous oil-containing waste and 2.5 g of oil and fat industry waste in a ratio of 1: 0.05, obtaining OK by mixing 40 g of calcium oxide and 5 g of spent silica gel in a ratio of 1: 0.125, respectively mixing the heated mixture with OK in a ratio of 1: 0.86. The resulting mixture in the process of quenching is heated to 118 ° C.

To quench calcium oxide according to equation (1) it is necessary:

40 · 18/56 = 12.6 g of water,

taking into account the water absorption of spent silica gel (10%): 50.12 = 0.6 g.

The necessary amount of water is contained in the oil sludge, additional introduction of water is not required.

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.

The resulting recycling products No. 1-6 are, in each example, a loose hydrophobic fine powder of light gray color with leachability PU1-6, less compared to the prototype. More environmentally friendly recycling products can be used to produce building materials that are resistant to water and aggressive environments.

Claims (1)

A method for the disposal of oily waste, including mixing preheated oily waste with waste from the oil and fat industry, adding a neutralizing composition, portioned while mixing, containing quicklime (calcium oxide) and spent silica gel, which is a waste of the gas preparation unit for transportation, followed by introduction calculated amount of water for the reaction with quicklime, the required amount of which is determined waste water taking into account the water available in the oil-containing waste and the water absorption of spent silica gel, characterized in that the oil-containing waste is mixed with the waste of the oil industry in the proportion 1: (0.05-0.2), recycled filter and absorption are used as waste oil industry waste mass obtained after repeated regeneration of diatomaceous filter powder, the neutralizing composition contains quicklime, ground to a finely dispersed state, and spent silica gel in a ratio of 1: (0.125-0.25), while the neutralizing composition is added to the waste mixture in a ratio of 1: (0.75-0.95) until a homogeneous hydrophobic granular fine powder is formed, and the oily waste is mixed with oil and fat industry wastes preheating to a temperature of 80-85 ° C.