RU2761208C1 - Method for cleaning tanks from oil residues and their utilization as a fuel mixture sended for combustion - Google Patents

Abstract

FIELD: tanks cleaning.

SUBSTANCE: invention relates to the field of cleaning tanks, such as tanks, from the remains of transported oil products. The invention relates to a method in which a washing solution is pumped from a tank for preparing a washing solution into a container to be cleaned after it is emptied, washing off residual oil products from the walls, a mixture of a washing solution with washed off oil products is poured into a filter settler, in which mechanical impurities are separated from the mixture, directed the mixture into sequentially located settling tanks, in which at least part of the washing solution is separated from the mixture and the separated part is directed to the inlet of the pump supplying it to the container to be cleaned, and the remaining mixture is disposed. The mixture from the filter-settling tank, before feeding it to the settling tanks, is poured into the tank for preparing the washing solution, in which part of the washing solution is separated from the mixture and the separated part is fed to the inlet of the pump for supplying the washing solution to the container to be cleaned, the mixture sent for disposal, is fed into separator tanks, in which it is further purified from the residues of the washing solution by carrying out successive replaceable processes of heating to 80-90°C and cooling to 60°C. A demulsifier is mixed into the mixture in the separator tanks to increase the efficiency of separating oil products from the mixture with the mixture being directed from the bottom of the separator tanks to the filter sump and the mixture is withdrawn from the upper part of the separator tanks for use as a combustible mixture sent for combustion, moreover, for heating the mixture in the separator tanks, a part of the heat obtained from the combustion of the combustible mixture is used.

EFFECT: increasing the efficiency of using oil products pumped from containers, as well as reducing costs due to the reuse of the detergent separated from oil products.

7 cl, 1 dwg, 1 tbl

Description

The invention relates to the field of cleaning tanks, for example, tanks, from residues transported in them oil products, as well as to the disposal of waste resulting from the cleaning of tanks.

There is a known method of cleaning containers from the residues of oil products transported in them and their disposal, which consists in the fact that from the tank for the preparation of the washing solution, a washing solution is pumped into the container to be cleaned after it has been emptied, washing off the residues of oil products from the walls, the mixture of the washing solution with the washed off oil products is drained into a settling tank, in which mechanical impurities are separated from the mixture, its vapor is removed from the mixture by means of exhaust devices, the mixture is sent to successively located settling tanks, in which at least part of the washing solution is separated from the mixture and the separated part of the washing solution is directed to the inlet pump feeding it into the container to be cleaned, and the remaining mixture is disposed of (RU2117636 C1, publ., 08/20/1998).

The disadvantages of this method is the insufficient efficiency of cleaning the mixture formed by mixing the washing solution with the residues of petroleum products.

The technical problem is the elimination of the noted drawback.

The technical result consists in increasing the efficiency of using oil products pumped from containers, by increasing the degree of their cleaning from the detergent used for washing the containers, as well as reducing costs due to the reuse of the detergent separated from the oil products.

The problem is solved, and the technical result is achieved by the fact that the washing solution is pumped from the tank for the preparation of the washing solution into the container to be cleaned after its emptying, washing off the residues of oil products from the walls, the mixture of the washing solution with the washed off oil products is drained into the filter-settler, in which mechanical impurities are separated from the mixture, the mixture is sent to sequentially located settling tanks, in which at least part of the washing solution is separated from the mixture and the separated part of the washing solution is sent to the inlet of the pump supplying it to the container to be cleaned, and the remaining mixture is disposed of, while, according to invention, the mixture from the filter-settling tank, before feeding it into the settling tanks, is poured into the tank for preparing the washing solution, in which part of the washing solution is separated from the mixture and the separated part is fed to the inlet of the pump for supplying the washing solution to the container to be cleaned, the mixture directed to disposal, is fed to the separator tanks, in which rykh carry out its further purification from the residues of the washing solution by carrying out successive replaceable processes of heating and cooling with the discharge of the mixture from the upper part of the separator tanks for further utilization and the direction of the mixture from the lower part of the separator tanks to the filter settler, while into the mixture in separator tanks, a demulsifier is added to increase the efficiency of separating oil products from the mixture, and the separated part of the mixture containing a large component of oil products is used as a combustible mixture sent for combustion, and part of the heat obtained during combustion of combustible is used to heat the mixture in the separator tanks mixtures.

Heating the mixture in the separator tanks can be carried out by heat exchange. Heating the mixture in the separator tanks can be carried out up to a temperature of 80-90 ° C, and its cooling is carried out by cooling it down to a temperature of 60 ° C. The mixture can be heated, at least in one of the settling tanks, to a temperature of 70-95 ° C. The mixture can be cleaned until the content of oil products in the recycled mixture is at least 98%. The washing solution can be fed into the container to be cleaned by a jet at a pressure of 10-12 atmospheres, and before feeding it can be heated to a temperature of 95 ° C. The detergent solution can be formed by dissolving the detergent in water until its constituent in the solution reaches 3-5% of the mass. After the mixture of the washing solution with oil products has been drained into the filter-settler, vapors of the mixture can be removed by means of exhaust devices.

The invention is illustrated using FIG. one.

The method is carried out using an installation containing a container to be cleaned 1, a tank 2 for the preparation of a cleaning solution supplied to the tank 1 to be cleaned by means of a pump 3, a filter-settler 4, in which, inter alia, by filtration, mechanical impurities are separated from the mixture washed out in it from tank 1. From the filter-settling tank 4, the mixture is sent back to tank 2, from which the mixture flows into successively located settling tanks 5 and 6, from which the mixture is directed by means of pump 3 further to the separating tanks 7, in which further purification is carried out mixtures from the remains of the cleaning solution. The separated combustible mixture of hydrocarbons is used as fuel sent for combustion, for example, in boiler furnaces. The remains of the washing solution from the separator tanks 7 are sent to the filter-settler 4.

Heating the mixture in the separator tanks 7 can be carried out by heat exchange, for example, using heat exchangers (not shown in the diagram) located inside the separator tanks 7.

The described method is implemented as follows. Tanks 1, in particular, railway tanks, after the discharge of oil products (gas oil, gas condensate, oil, fuel oil, gasoline, diesel fuel, heating oil, oils, etc.) surfaces of boilers of tanks.

From reservoir 2 a washing solution is supplied by a pump 3 to the container 1 to be cleaned, washing off the residues of oil products from its walls. An aqueous solution with a detergent (Tekhron-O) in the amount of 3-5 mass is used as a washing solution. %, until the solution density reaches 1.025 - 1.042. Techron-O contains soda ash, ionic surfactant, nonionic surfactant, sodium liquid glass, technical polyacrylamide.

The washing solution is heated in tank 2 and fed into tank 1 at a washing solution temperature of 70-95 ° C under a pressure of 10-12 atmospheres.

Formed in the container 1, a mixture of the washing solution and washed off oil products through the device of the bottom drain of the container 1 enters the filter-settler 4 to separate mechanical impurities. After removing mechanical impurities, the mixture of the washing solution and washed off oil products enters the tank 2 for the preparation of the washing solution. Then the mixture is sent to sequentially located settling tanks 5 and 6. Both in tank 2 and in tanks 5 and 6, at least part of the washing solution is separated from the mixture and the separated part of the washing solution is directed to the inlet of pump 3, which supplies it to container to be cleaned 1. The portion of the cleaning solution thus separated is reused.

Then, from the sequentially installed settling tanks (pos. 6), the mixture with a reduced content of the washing solution in it is sent to the separating tanks 7, in which it is further cleaned from the residues of the washing solution by carrying out successive replaceable heating and cooling processes, which are carried out until those until the percentage of the washing solution in the mixture with hydrocarbons is less than 2 vol. %.

To speed up the process of additional residual separation of the washing solution, a demulsifier is additionally added to the separating tanks 7 - nonionic surfactants, for example, proxanols 146, 186, 305, proxamine 385 and diproxamine 157 (Pralt-11) at the rate of 30-50 grams per ton of mixture. In the diagram, the arrows show the supply of surfactants to the separator tanks 7.

The mixture is heated with the help of heat exchangers, for example, in the form of a coil (not shown in the diagram), into which steam is supplied from the combustion of fuel obtained as a result of cleaning the mixture from the boiler room. Heating temperature 80-90 ° С. After heating to a predetermined temperature, the valves are closed, and the mixture cools naturally to 60 ° C, after which heating and cooling are repeated until the final result is obtained, which consists in reducing the content of detergents and obtaining a combustible mixture containing at least 98% of hydrocarbons.

From the bottom of the separator tanks 7, the separated part of the mixture with the washing solution is fed into the filter-settler 4 and, after it enters the tank 2, is reused to clean the tank 1. The cleaned fuel comes from the upper part of the last separator tank 7 into the boiler room for combustion ...

The composition of the mixture is controlled by taking samples from control valves at different levels of the tank (at the end). The samples are visually inspected and then the percentage of water cut is measured with the device. After obtaining the required hydrocarbon mixture with the required characteristics (Table 1), it is supplied to the consumer for incineration, and the washing solution into the filter-settler 4, and then into the tank 2 for preparing the washing solution.

The hydrocarbon mixture sent to the consumer for combustion is a liquid product consisting of various oil products with the presence of an unseparated washing solution of less than 2 vol%. According to the GOST28576 classification, such a mixture can be classified as fuels.

The mixture has a color ranging from yellow to almost black (depending on the raw material).

In terms of physical and chemical indicators, the hydrocarbon mixture corresponds to the indicators in Table No. 1.

Table 1

Indicator name Norm Test Method 1 Nominal viscosity at 20 ° C, s, or from 13 to 40 * GOST 26378.3 kinematic viscosity at 50 C, mm ² / s (cSt) from 5 to 35 * GOST 33 and 5.8 2 Flash point, determined in an open crucible, ° С, not lower than 70 GOST 26378.4, GOST 4333 and 5.8 3 Mass fraction of mechanical impurities,%, no more one GOST 26378.2 4 Mass fraction of water,%, no more 6 GOST 26378.1, GOST R 51946 or GOST 2477 5 Contamination content absence GOST 26378.2 6 Mass fraction of fractions boiling up to 340 ° С,%, no more 10 GOST 2177 7 Pour point of fractions boiling above 340 ° С, not higher minus 10 GOST 20287 8 Density at 20 ° С, kg / m ³ , no more 950 GOST 3900 or GOST R 51069 Notes:
1 * Allowed values of the indicator above the indicated ones.
2 Indicator 8 is not a rejection indicator.
3 If disagreements arise in assessing the quality of the hydrocarbon mixture, the mass fraction of mechanical impurities is checked in accordance with GOST 6370.

The resulting hydrocarbon mixture is used, for example, as a liquid fuel for the operation of a boiler house.

Thus, the claimed method makes it possible to significantly increase the efficiency of cleaning a mixture with petroleum products with its separation into fuel used in industry, as well as detergents used repeatedly for cleaning containers.

Claims (7)

1. A method of cleaning containers from residues of oil products transported in them, which consists in the fact that from a tank for preparing a washing solution, a washing solution is pumped into a container to be cleaned after it has been emptied, washing off residues of oil products from the walls, a mixture of a washing solution with washed oil products is drained into a filter a settling tank, in which mechanical impurities are separated from the mixture, the mixture is sent to successively located settling tanks, in which at least part of the washing solution is separated from the mixture and the separated part is directed to the pump inlet, which feeds it into the container to be cleaned, and the remaining mixture is disposed of characterized in that the mixture from the filter-settling tank, before feeding it into the settling tanks, is poured into the tank for preparing the washing solution, in which part of the washing solution is separated from the mixture and the separated part is fed to the inlet of the pump for supplying the washing solution to the container to be cleaned, the mixture sent for disposal is fed to the separator tanks, in which it is further purified from the residues of the washing solution by carrying out successive replaceable processes of heating to 80-90 ° C and cooling to 60 ° C, while a demulsifier is added to the mixture in the separator tanks to increase the efficiency of separating oil products from the mixture with directing the mixture from the lower part of the separator tanks to the filter settler and withdrawing the mixture from the upper part of the separating tanks for use as a combustible mixture directed for combustion, and part of the heat obtained during combustion of the combustible mixture is used to heat the mixture in the separator tanks. 2. The method according to claim 1, characterized in that the heating of the mixture in the separator tanks is carried out by means of heat exchange. 3. A method according to claim 1, characterized in that the mixture is heated, at least in one of the settling tanks, to a temperature of 70-95 ° C. 4. The method according to claim 1, characterized in that the mixture is purified until the content of oil products in the recycled mixture is at least 98 vol. %. 5. The method according to claim 1, characterized in that the cleaning solution is fed into the container to be cleaned by a jet at a pressure of 10-12 atmospheres, and before feeding it is heated to a temperature of 95 ° C. 6. The method according to p. 1, characterized in that the washing solution is formed by dissolving the detergent in water until its constituent in the solution reaches 3-5 wt. %. 7. The method according to claim 1, characterized in that after draining the mixture of the washing solution with oil products, vapor of the mixture is removed into the filter-settler by means of exhaust devices.

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