RU2471725C2 - Method of decontaminating and recycling oily sludge - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to methods of decontaminating and recycling oily sludge and can be used particularly in oil and gas companies. The method of decontaminating and recycling oily sludge involves mixing oily sludge with unslaked lime, mineralised water and a modifier - spent silica gel. The mixture is additionally treated with a constant electric field until the end of the process of formation of a calcium silicate structure, with the following parameters of the electrokinetic process: voltage across electrodes 4-50 V, field strength 2-20 V/m, current density 0.1-2.0 A/m², distance between electrodes 0.5-3.0 m.

EFFECT: obtaining an environmentally safe decontamination product as a secondary material resource.

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Description

The invention relates to methods for the disposal and disposal of oily sludge and can be used at industrial facilities of the oil and gas complex, which is the formation, storage and long-term storage in sludge collectors of a significant amount of oily sludge.

The current situation in the use, storage, burial and disposal of oily waste (sludge) leads to dangerous pollution of soil, air and groundwater, significant economic damage and poses a huge threat to the environment.

There are various methods of disposal and processing of oily sludge depending on their composition, physico-chemical properties, specific conditions and technical capabilities of the enterprise (thermal, mechanical, chemical, physico-chemical, biological). For effective waste disposal, of interest are technologies that cause minimal environmental damage to the environment, have low capital costs and allow profit. The most rational method of waste disposal is to use them as secondary material resources.

A known method of disposal of waste containing oil and oil products (RF Patent No. 2187466), which consists in mixing waste with a neutralizing component, which is used as calcium oxide (10-40% by weight) and magnesium (3-5% by weight).

The disadvantage of this method is the high alkalinity of the aqueous extract of the product obtained by this technology, due to the formation of calcium hydroxide in the process of extinguishing lime, as well as in the aqueous extract, a significant amount of petroleum products is detected, indicating the ineffectiveness of the disposal of oily waste.

A method of processing oily sludge using a working agent (RF Patent No. 2266258) (analogue), the main component of which is calcium oxide, followed by the introduction of a liquid that reacts with the working agent. The oil-containing sludge is pre-mixed until a homogeneous mixture is uniform in composition and viscosity when heated to a temperature of 50-80 ° C and the introduction of an organic thinner of not more than 5%. Then mixed with a working agent (calcium oxide 90-100% by weight and modifier - the rest), adding the required amount of water or clay milk, and get a granular product.

The invention adopted as a prototype includes the preparation of a neutralizing composition and its mixing with oily sludge. The neutralizing composition is obtained by mixing pre-ground quicklime (calcium oxide) in an amount of 70-75% by weight and a modifier (spent silica gel) - waste gas industry at the stage of drying natural gas, in an amount of 25-30% by weight for 15-20 minutes . The amount of water required to completely extinguish the lime is added to the oily sludge, taking into account the available silica and the water absorption of the spent silica gel. The neutralizing composition is mixed with oily sludge in the ratio of (1.5-2) ÷ 1 (RF patent No. 2395466 С02F 11/14, B09B 3/00).

The main disadvantages of the method are the dependence of the degree of neutralization on the mixing efficiency and purity of the reagent. The resulting powder does not have absolute hydrophobic properties, and when water enters the pore space, native microflora gradually decomposes the organic substances that make up the powder, which leads to secondary pollution of the surrounding environment.

The aim of the invention is to develop a more effective method of disposal and disposal of oily sludge to obtain an environmentally friendly product of neutralization as a secondary material resource.

The goal is achieved in that a method for the treatment of oily sludge, comprising mixing an oily sludge with a neutralizing composition containing quicklime (calcium oxide) as the main component, followed by the introduction of water reacting with quicklime and a modifier, mix and grind them to a finely divided state until the end of the process. formation of a calcium silicate structure, and is affected by a constant electric field, causing electrochemical disinfection, electrochemical oxidation and electrodestruction of oily sludge.

Achieving a positive effect in the proposed method is ensured by a complex electrochemical effect. Due to the electrolytic decomposition of chemical compounds and the purification of oily sludge from microorganisms, also as a result of electrochemical oxidation, the oily sludge is purified from chlorinated hydrocarbons and phenol. At the same time, as a result of electrical destruction, decomposition of toxic organic compounds on the electrodes will occur with the formation of less toxic substances. The formation of OH hydroxyl group as a result of electrochemical reactions during the decomposition of mineralized water under the influence of an electric field leads to additional oxidation of oil sludge and its disinfection. Processing sludge in a constant electric field can also reduce the consumption of reagents used.

The transfer of oily sludge from a highly viscous state to bulk facilitates its transportation, while there is an improved encapsulation of harmful sludge substances that impedes the migration of oil products into the environment when used, for example, as a complex organo-mineral additive in the production of building materials.

Parameters of the electrokinetic process: voltage at the electrodes 4 ... 50 V, field strength 2 ... 20 V / m, current density 0.1 ... 2.0 A / m ² , the distance between the electrodes 0.5 ... 3.0 m. The effectiveness of the disposal of oil sludge is 80 ... 99% It is impossible to achieve high purification without applying an electric field. The cost of disposal is from 130 to 190 rubles. per 1 m ^{3 of} oil sludge. A cathodic protection station with a power of up to 10 kV can be used as a direct current source.

The invention is illustrated by graphic material, where the following designations are accepted: a barn with oil sludge - item 1, intake device - item 2, a screw pump - item 3, a mixer-reactor - item 4, a container with quicklime (cement truck) - item. 5, modifier dispenser (spent silica gel) - pos.6, regulator pos.7 of mineralized water intake, ion-plasma generator consisting of electrode (s) - pos.8, and stabilized constant voltage source - pos.9, belt conveyor -pos. 10.

The method is implemented as follows. The oil sludge located in the barn - item 1, is taken with a suction device - item 2 and pumped out by a screw pump - item 3 into the mixer-reactor - item 4, which is also filled with quicklime from cement truck 5, mineralized water through a regulator - pos.7 and modifier - spent silica gel through the dispenser - pos.6. The neutralizing composition is mixed with oily sludge in the ratio of (1.5-2) ÷ 1 and treated in a constant voltage field implemented from the electrode (s) - pos.8, and a stabilized constant voltage source - pos.9, and the electrodes are connected to the “positive” ”To the power pole, and“ negative ”to the mixer-reactor vessel. Mineralized water through the regulator - item 7 is supplied in an amount sufficient to make the dispersion medium water. Organomineral powder, the final product of disposal, enters the conveyor belt - item 10. The finished (solid) product should be used for profiling the surface of the embankments of mining bushes, solid waste landfills, as well as in the production of building materials.

Thus, the proposed method for the integrated treatment of oily sludge can achieve the goal in the most simple and cheap way. The principal features of the method are:

- destruction of the structural lattice of paraffinic oils and bitumen by reducing the effective viscosity, improving circulation and heat transfer;

- electrochemical and microbiological disinfection of waste oil and gas complex with the possibility of further use as an organomineral additive;

- localization of hazardous areas and installation of equipment in explosion-proof execution;

- the effectiveness of oil sludge disinfection is increased due to its deeper degassing, improved industrial safety and the prevention of environmental damage.

Sources used

1. RF patent No. 2187466 (analogue).

2. RF patent No. 2395466 (prototype).

Claims (1)

A method of neutralizing and disposing of oil-containing sludge, including mixing oil-containing sludge with quicklime, mineralized water and a modifier - spent silica gel, characterized in that the mixture is further processed until the formation of calcium silicate structure by a constant electric field with the following parameters of the electrokinetic process: voltage on electrodes 4 50 V, field strength 2-20 V / m, current density 0.1-2.0 A / m ² , the distance between the electrodes 0.5-3.0 m

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