RU234052U1 - Sedimentation tank - Google Patents

Abstract

The utility model relates to the oil refining and petrochemical industries and can be used for gravity settling of paraffinic oil, fuel oil and oil sludge. The settling tank includes a vertical cylindrical tank with a conical lower part, a built-in device for heating with circulation. The device contains a vertical housing, the upper end of which is sealed, and the lower end communicates with the vertical cylindrical tank. The side through branches are welded at an angle of 90 degrees to the surface of the housing. The openings at the ends of the side branches are directed downwards. The device contains built-in tubular heaters. A metal housing of the first bearing is welded to the upper end of the vertical housing. The metal housing of the second bearing is welded to the profile pipe for fastening the bearing to the vertical housing in its lower part. The pumping blades with a hub are attached to the rotation shaft of the pumping blades. A hydraulic circulation drive is installed on top of the device for heating with circulation. The rotation shaft of the pumping blades, connecting the pumping blades with the hydraulic circulation drive, is installed in the first and second bearings. Channels for fastening the device for heating with circulation, welded together in one plane at the same distance from each other, are fixed on the walls of the vertical cylindrical tank. A tubular coil is installed vertically in the lower conical part of the vertical cylindrical tank. The inlet opening of the lower conical part of the vertical cylindrical tank is hermetically welded to the outlet of the coil tube. The technical result of the utility model consists in increasing the efficiency of settling oil and oil products. 1 ill.

Description

The utility model relates to the field of oil refining and petrochemical industries and can be used in the gravitational settling of paraffin oil, fuel oil and oil sludge.

The prior art provides various designs of oil separators or settling tanks, in which the processing of oil-containing media is carried out mainly by passing the working mass through liquid filters or mechanical filter elements [https://rzmash.ru/otstojniki-nefti/; https://boilerprom.ru/shop/emkostnoe_oborudovanie/vertikalnyj-otstojnik/].

Some designs of settling tanks use guide blades of various shapes and sizes exclusively for the intake, swirling and discharge of gas, oil and water, respectively [patents RU 102057 U1, application No. 2010137678/03 dated 09.09.2010; RU 2258555 C1, application No. 2003138294/15 dated 29.12.2003; RU 156529 U1, application No. 2014143521/05, 13.01.2015].

The basic operating principle of separators in the oil industry is long-term settling and mechanical separation.

Heating is used to accelerate the settling process of emulsions and suspensions. Heating can be done in the settling tank itself or outside it [Baykov N.M., Pozdnyshev G.N., Mansurov R.I. Collection and industrial preparation of oil, gas and water. Moscow: Nedra, 1981, p. 155]. However, in practice, the desired effect is often not achieved. Due to the difference in liquid temperatures in the settling tank, strong convective currents arise, which interfere with the settling process.

There are proposals [Kasatkin A.G. Basic processes and apparatuses of chemical technology, Publ. GHI, Moscow, 1960, p. 205] that the heating elements in settling tanks should be designed and positioned so that vertical liquid currents do not occur. This is achieved by positioning the heating elements vertically along the entire height of the settling tank to achieve a uniform temperature, and therefore, the same density of the liquid. However, even in this case, the stated goal is not achieved, since during heating in any case there is a temperature difference and convective movement occurs.

Thermal conductivity is the process of transferring heat through the thermal motion of molecules or atoms. The amount of heat transferred by a layer of material of thickness and area S while maintaining a temperature difference ΔT on its surfaces for time t, is equal to:

,

Where - thermal conductivity coefficient, numerically equal to the amount of heat transferred in 1 s through a layer 1 m thick and a surface area of 1 ^m2 with a surface temperature difference of 1 K. Thermal conductivity coefficients have dimensions in SI units of W/(m×K). In practice, I kcal/(m×h×K) is used (I kcal/(m×h×K) = 1.163 W/(m×K)).

Under normal conditions (p = 1.033×10^5 H/m^2 and t = 0), the thermal conductivity coefficients of individual components of oil well products are (W/m×K):

for oil gas 0.01-0.03 for commercial oil 0.14-0.16 for formation waters 0.54-0.65

It should be noted that paraffinic oils and aggregate-stable concentrated emulsions have the property of spontaneous increase in the strength of the structure over time and restoration of the structure after its destruction. This property is called thixotropy. The time of thixotropic restoration of the structure after its mechanical destruction for different oils and emulsions is different and fluctuates in a wide range - from several minutes to tens of hours. The thixotropic properties of oils depend on the content, chemical composition, colloidal-dispersed state of high-melting paraffin components of oil, the content and adsorption effect on the crystallization processes of paraffin, asphalt-resinous substances, residual amount of reagent-demulsifier, temperature effect on oil, etc. A large number of works are devoted to studies of the effect of temperature (heat treatment) and additions of special depressant additives on the reduction of structural-mechanical and thixotropic properties of oils. However, many physical and physicochemical processes occurring with high-melting paraffin hydrocarbons of oil during their heat treatment or introduction of additives of various chemical compositions remain unclear. Some depressant additives, which effectively reduce the viscosity of oils and crudes with a small content of asphaltenes and resins, have virtually no effect on the viscosity characteristics of oils with an increased content of resins and asphaltenes.

The technical result of the utility model consists in increasing the efficiency of settling oil and oil products.

In this case, the heating of the liquid being settled, which is kept for the required time, will occur during its circulation in the settling tank.

The technical result is achieved by the fact that the settling tank includes:

a vertical cylindrical container with a conical bottom,

a heating device with circulation built into a vertical cylindrical container, comprising

a vertical body, the upper end of which is sealed, and the lower end communicates with a vertical cylindrical container, with side through branches welded at an angle of 90 degrees to the surface of the body, while the openings at the ends of the side branches are directed downwards,

built-in tubular heaters,

the first bearing, installed in a seat, the metal housing of which is welded to the upper end of the vertical housing,

the second bearing, installed in a seat, the metal housing of which is welded to the profile pipe for fastening the bearing to the vertical housing in its lower part,

pumping blades with a hub attached to the pumping blade rotation shaft,

hydraulic circulation drive installed on top of the heating device with circulation,

a shaft for rotating the pumping blades, connecting the pumping blades with the hydraulic circulation drive and installed in the first and second bearings,

channel bars for fastening the heating device with circulation, welded together in one plane at the same distance from each other and secured to the walls of the vertical cylindrical tank using threaded studs and tightening nuts welded to the vertical cylindrical tank,

a tubular coil installed vertically in the lower conical portion of a vertical cylindrical container, wherein the inlet opening of the lower conical portion of the vertical cylindrical container is hermetically welded to the outlet of the coil tube.

In this case, the vertical body of the heating device with circulation is made of metal, and the area of the holes of the side through branches corresponds to the area of communication with the settling tank in the lower part of the heating device with circulation.

The design of the utility model is shown in the drawing, where 1 is a settling tank, 2 is a vertical housing, 3 are tubular heaters, 4 are lateral through branches, 5 is the first bearing, 6 are injection blades, 7 are threaded studs, 8 is a shaft for rotating the injection blades, 9 are mounting channels, 10 is a hydraulic circulation drive, 11 is a tubular coil, 12 is a sludge drain valve, 13 is a profiled bearing mounting pipe, 14 is the second bearing.

The size of the heating device with circulation is calculated depending on the cross-sectional area of the device and the cross-sectional area from the walls of the settling tank 1 to the vertical body 2 of the device. The height of the device is 3/4 of the settling tank 1, 1/4 of the settling tank 1 is the settling zone.

The device for heating with circulation has a vertical housing 2. The end face of the upper part of the vertical housing 2 is sealed, and in the side part, lateral through branches 4 are mounted at an angle of 90 degrees to the surface of the device, directed with holes downwards. The lateral through branches 4 communicate with the inner part of the device. Tubular heaters 3 are mounted inside the device. The end face of the lower part communicates with the settling tank 1. To create circulation, the device has pumping blades 6, driven into rotation by shaft 8. The rotation shaft of the pumping blades 8 has two bearings, wherein the first bearing 5 is mounted on the end face of the upper part of the device, having an opening for shaft 8. The size of the opening is equal to the diameter of the housing of the bearing seat 5. The housing of the seat is welded to the end face of the device. The second bearing 14 is installed in the lower part of the rotation shaft of the pumping blades 8. The seat of the second bearing 14 also has a metal housing welded to the profile pipes of the bearing mount 13, which are attached to the vertical housing 2 of the device.

To support the heating device with circulation inside the settling tank 1 in a suspended state, fastening channels 9 are used. The channels 9 are welded together in one plane at the same distance from each other and have holes for the diameter of the threaded studs 7. The threaded studs 7 are welded to the heating device with circulation from the inside. The channels 9 are mounted on the walls of the settling tank 1 by putting them on the threaded studs 7 and secured by tightening nuts larger than the holes in the channels.

When the liquid being settled is heated in the settling tank 1, the evaporation of light, easily flammable fractions will occur, so the use of an electric motor in the installation is not allowed. This utility model provides a hydraulic circulation drive 10 for driving the shaft 8 by means of hydraulic energy. The rotation speed is adjusted by the flow rate.

The tubular coil 11, installed in the lower conical part of the settling tank 1, is located vertically and is provided in the claimed design for reducing the temperature of the settling tank due to the circulation of the cooling liquid. The outlet pipe of the settling tank 1, located in the conical part, is hermetically welded to the tubular coil 11.

The utility model works as follows.

After filling the settling tank 1 with the liquid to be settled, the liquid to be settled is heated and circulated using a heating device with circulation with built-in tubular heaters 3. Creating circulation during heating is necessary for efficient heating of the liquid to be settled with a small thermal conductivity coefficient and destruction of the structure of liquids with pronounced thixotropy (paraffin oils, fuel oil, oil sludge). The components of the liquid to be settled also have different coefficients of volume expansion, and when heated, with an increase in temperature, the density of water decreases according to a linear law, but significantly less than the density of oil. This means that with an increase in temperature, the difference in the densities of mineralized wastewater and oil increases. This heating method allows maintaining the same temperature of the components of the liquid to be settled and creating an additional difference in density during heating.

Circulation occurs due to the rotation of the pumping blades 8, installed in the lower part of the device for heating with circulation, which take in liquid through the lower part of the device and pump it through the device with installed tubular heaters 3. The outlet occurs through the openings of the side through branches 4.

After the liquid is discharged, its movement will take place between the wall of the settling tank 1 and the heating device with circulation to the liquid intake opening. The settling components are discharged by means of the sludge drain valve 12, located at the bottom of the conical part of the settling tank 1.

The utility model provides for the use of thermal and rheological properties of liquids to reduce settling time and, accordingly, increase the efficiency of periodic settling.

Claims (3)

1. A settling tank comprising a vertical cylindrical tank with a conical lower part, a device for heating with circulation built into the vertical cylindrical tank, containing a vertical housing, the upper end of which is sealed, and the lower end communicates with the vertical cylindrical tank, with lateral through branches welded at an angle of 90 degrees to the surface of the housing, wherein the openings at the ends of the lateral branches are directed downwards, built-in tubular heaters, a first bearing installed in a seat, the metal housing of which is welded to the upper end of the vertical housing, a second bearing installed in a seat, the metal housing of which is welded to a profile pipe for fastening the bearing to the vertical housing in its lower part, pumping blades with a hub attached to the shaft of rotation of the pumping blades, a hydraulic circulation drive installed on top of the device for heating with circulation, a shaft of rotation of the pumping blades, connecting the pumping blades with the hydraulic circulation drive and installed in the first and second bearings, channels for fastening the device for heating with circulation, welded together in one plane at the same distance from each other and secured to the walls of the vertical cylindrical tank with the help of threaded studs and tightening nuts welded to the vertical cylindrical tank, a tubular coil installed vertically in the lower conical part of the vertical cylindrical tank, wherein the inlet opening of the lower conical part of the vertical cylindrical tank is hermetically welded to the outlet of the coil tube. 2. A settling tank according to item 1, characterized in that the vertical body of the device for heating with circulation is made of metal. 3. A settling tank according to item 1, characterized in that the area of the openings of the side through branches corresponds to the area of communication with the settling tank in the lower part of the device for heating with circulation.