RU2114786C1 - Installation for removing petroleum products and solids from waste waters - Google Patents

Abstract

FIELD: waste water treatment. SUBSTANCE: waste water is fed into tank and then into magnetohydrodynamic inductor to be magnetically treated to enhance coalescence ability of petroleum product. Treated waste water comes into casing cylinder in tangential direction resulting in fall of coarse solid particles down. Afterwards, stream comes into coalescence chamber where oil films are formed on polystyrene granules and then, after detachment, transform into drops. In settler, waste water passes layer of hydrophilic charge whose granules transport oil drops. In the chamber, polystyrene granules take off oil drops and carry them toward partition. Oil passes the latter, reaches phase interface, and supplements oil layer. Cleaned water turns downward, passes hydrophilic partition, and comes out through pipeline into tank from which it leaves the installation. EFFECT: enhanced water cleaning efficiency.

Description

 The invention relates to the field of wastewater treatment, in particular to a device for wastewater treatment from oil products and solid impurities.

 To improve the environmental situation in many sectors of the economy, for example, oil, metallurgy, chemical, sea and river transport, wastewater treatment from oil products and solid impurities is required. For these purposes, filters, sedimentation tanks, and separators are widely used, which make it possible to treat waste water with a sufficiently high degree of separation of pollution products from it. In the patent of the Russian Federation N 2019263, cl. B 01 D 24/30 describes a filter for treating wastewater from oil products and suspended particles. It contains a housing with a lid and a bottom, a floating filter load in the form of polystyrene grains, a distributor, a drainage system and a cylindrical shell with a nozzle for draining the wash water connected to the bottom.

 The filter design allows to achieve a relatively high degree of purification of wastewater from solid impurities, however, the degree of purification from oily products is not high enough, since it does not provide for the removal of oil from the filter during the cleaning process. Oil accumulates in grains and is washed from them only during the regeneration process. Expanded polystyrene serves as a filter element, and not as a coalescing one.

 In auto USSR N 1301443, class B 01 D 17/02 describes a coalescing filter for wastewater treatment from petroleum products. It contains a housing, a coalescence chamber, upper and lower grids, between which coalescing material is placed, a settling chamber for collecting oil products, a pipe for their discharge, a pipe for introducing wastewater, a glass for changing the direction and speed of its flow, and a pipe for removing purified water, placed coaxially to the glass and lowered into it. The known filter provides a significant degree of purification from oil products, however, it does not provide for the separation of solid particles from wastewater outside the coalescing chamber, which entails clogging of the coalescing material from solid impurities, and therefore, the filter stops operating frequently.

 In auto USSR N 1212463, class B 01 D 17/02 describes a plant for treating wastewater from oil products and solid impurities. It contains a cylindrical body with a cover, inside of which there is a chamber with a coalescing nozzle, a sump and an additional cleaning chamber. In its lower part there are pipes for the input of sewage and withdrawal of purified water, and in its upper part there is a pipe for the removal of oil product. A device for heating concentrated wastewater with a high content of, for example, paraffin, is located at the inlet of the wastewater into the casing. It is made in the form of a steam heating coil in order to reduce the viscosity of the mixture. Wastewater, passing the heating zone, enters the settling chamber, where under the influence of gravitational forces, the bulk of the oil product is separated. Next, the water enters the coalescing chamber, where droplets of petroleum products adhere to the coalescing nozzle. Coarse droplets are carried out with water into the gravity settler, where they float up. The process ends in an additional purification chamber, where it is filtered through a layer of coalescing granules. During the cleaning process, solid suspensions are retained in the pores of the coalescing nozzle, which worsens the degree of water purification. The restoration of the properties of the granular nozzle is carried out by washing it with a counter flow of water, for which the cleaning process is stopped.

 The design of the known installation allowed to increase the degree of wastewater treatment from pollution. However, the relatively short cycle of the installation and the duration of the regeneration process reduce its productivity and increase the complexity. In addition, gravitational forces in the stream cannot fully ensure the removal of coarse droplets of oil from the unit due to the lack of a contact mechanism for their separation from water.

 The objective of the invention is the creation of such a design of the installation, which would include increasing both the depth of wastewater treatment from oil products and solid impurities, and the productivity of the process by increasing the duration of the filter cycle.

 The problem is solved due to the fact that the installation is equipped with a device located at the inlet of wastewater in the casing to reduce its stability, made in the form of a magnetohydrodynamic inductor, as well as wastewater and purified water tanks connected to the casing with nozzles fixed to them, and a pipe for discharging purified water is located below the pipe for the removal of petroleum products, the housing is equipped with a lower hydrophobic, middle hydrophilic and upper hydrophobic perforated partitions, as well as a central pipe with reinforced a glass made on it, made with a conical bottom and with an internal hydrophilic partition and forming a gap with the upper partition, a chamber with a coalescing nozzle is enclosed between the lower and middle partitions, a sump and an additional cleaning chamber are between the middle and upper partitions, the upper partition is installed below the nozzle for the removal of petroleum products and is movably connected to the housing cover, and its lower part is made in connection with a cylinder of a smaller diameter with the formation of a water distribution chamber.

 The technical result is an increase in the degree of removal from wastewater of both petroleum products and solid impurities, as well as an increase in the cycle of the cleaning process.

 The drawing shows a General view of the installation before starting the cleaning process.

где
Δh - разница в уровнях размещения патрубков;
δ $\genfrac{}{}{0ex}{}{\text{о}}{\text{н}}$ - начальная толщина слоя нефтепродукта;
ρ_н - плотность нефтепродукта;
ρ_в - плотность воды.The installation comprises a housing 1, tanks 2, 3 for wastewater and purified water with nozzles 4, 5 and a magnetohydrodynamic inductor 6 for pretreatment of wastewater located at the entrance to the housing 1. The latter is made in the form of a cylinder, in the upper part of which there is a cover 7 and its lower part is made in the form of a cylinder 8 of smaller diameter. Inside the housing 1, the central pipe 9 is fixedly mounted with a glass 10 fixed on it with a conical bottom 11 and an internal hydrophilic partition 12. In the housing 1 are located the lower hydrophobic, middle hydrophilic and upper hydrophobic perforated partitions 13, 14 and 15. The latter is connected to the cover 7 through the rod 16, made with the possibility of movement. The upper partition is located above the glass 10 with the formation of a gap 17. Between the lower and middle partitions 13, 14 there is a coalescing chamber 18 with a bulk hydrophobic nozzle in the form of polystyrene granules, between the middle and upper partitions 14, 15 there is a settler 19 with a bulk transporting nozzle in the form of granules polystyrene and an additional cleaning chamber 20 with an auxiliary bulk nozzle in the form of polystyrene foam granules, and a water distribution chamber 21 is enclosed in the cylinder 8. In the upper part of the housing 1 above the upper partition 15 a pipe 22 for removing oil products has been installed. The axis of this pipe is removed from the axis of the pipe 5 of the vessel 3 by a distance calculated in accordance with the formula derived from the law of communicating vessels

Where
Δh is the difference in the levels of the nozzles;
δ $\genfrac{}{}{0ex}{}{\text{about}}{\text{n}}$ - the initial thickness of the layer of oil;
ρ _n is the density of the oil product;
ρ _in - the density of water.

 On the side wall of the housing 1 between the lower and middle partitions 13, 14 and between the middle and upper partitions 14, 15 loading and unloading pipes 23, 24 and a tee 25 are installed, the latter having valves 26, 27. A tee 28 is located in the lower part of the housing 1 with two valves 29, 30, a pipe 31 for supplying compressed air to the housing and a pipe 32 connecting the housing 1 through a pipe 33 to a container 2. A magnetohydrodynamic inductor 6 for magnetically treating wastewater is placed on the pipe 33. The Central pipe 9 is connected by a pipe 34 with a capacity of 3 through the valve 35 and to the flushing water supply system through the valve 36.

 Installation in accordance with the invention operates as follows.

 Before the cleaning process, the installation is prepared for operation. The coalescing chamber 18 through the pipe 23 or 24 is filled with a coalescing nozzle - expanded polystyrene granules to a predetermined level. Through a tee 25 with the valve 27 open, a predetermined amount of a transporting nozzle — polystyrene granules and an auxiliary nozzle — polystyrene foam granules, is loaded into the sump 19. The cover 7 is installed on the housing 1 and by moving the rod 16 provide a predetermined gap 17 between the cup 10 and the partition 15. Then, through the open valve of the pipe 32 with the open valve 35 from the tank 2, pure water is supplied to the housing 1 by means of a pump, while the granules light polystyrene foam float in the coalescing chamber 18 to the partition 14, and in the sump 19 to the partition 15, forming a chamber 20 for additional cleaning. The water supply process is carried out until clean water begins to pour out from the nozzle 5 of the tank 3. The water level in the housing 1 will occupy the position between the partition 15 and the nozzle 22, corresponding to the position in the communicating tank 3. After that, pour through the nozzle 22 into the housing 1 layer 37 of the oil product until the level of discharge from it is reached, while the excess water is displaced into the tank 3 and poured out through the nozzle 5. A hydrostatic equilibrium is established in the system of communicating vessels 1, 3 and the interface: water - oil product. The interface corresponds to the level of the partition 15. Communicating vessels 1, 3 are connected to the atmosphere by automatic pneumatic valves 38, 39.

 The wastewater treatment process is carried out as follows.

 Waste water through the pipe 4 is fed into the tank 2, for example, using a pump. Wastewater through a pipe 33 passes through a magnetohydrodynamic inductor 6, where it is subjected to magnetic treatment in order to reduce its stabilization, greatly facilitating the coalescing ability of the dispersed phase - the oil product. After this treatment, the wastewater through the nozzle 32 enters the cylinder 8 in the tangential direction, providing a swirling flow. In this case, large particles of solid impurities descend downward, and the swirling flow of water, rising upward, undergoes a sudden expansion in the water distribution chamber 21, transforming into a flow of equal velocity over the cross section. A uniform flow of wastewater through the baffle 13 enters the coalescing chamber 18. On the surface of the polystyrene granules, the dispersed phase coalesces to form oil product films, which then break away from the granules and turn into droplets. Wastewater with coarse droplets passes through a baffle 14 into a sump 19 through a layer of a transporting nozzle - polystyrene granules, which is a hydrophobic material. In the settling tank 19, its granules capture, coalesce and transport droplets of oil product on themselves, changing the balance of buoyancy from negative to positive. Moving with acceleration in the gap between the cone 11 and the housing 1, the polystyrene granules with the oil droplets together with the water stream reach the additional purification chamber 20 containing an auxiliary floating nozzle that draws oil product droplets from them. Having given the petroleum product, polystyrene granules fall down. In the chamber 20, an intensive process of separating the oil product from the water and moving it to the partition 15 takes place. The coalesced oil product and the auxiliary nozzle form a contact oil medium that facilitates the capture of oil product droplets from the stream and their movement, along with the lifting force, to the interface. When the level of glass 10 is reached, the direction of movement of the water and oil product changes: the latter moves up, the water moves down. The oil passes through the partition 15, reaches the phase separation and replenishes the layer 37. The thickness of this layer increases and when the level of the pipe 22 is exceeded, the oil is poured through it into the receiver. The water purified from large drops, turning down, passes through the hydrophilic partition 12. The latter does not pass the oil product through itself. It pops up and, falling under the influence of a contact oil medium, is absorbed by it. The water completely purified from the oil product through the central pipe 9 through the pipe 34 with the valve 35 open enters the tank 3 and through the pipe 5 is removed from the installation.

 The solid impurities carried out by the water flow into the housing 1 accumulate in the polystyrene foam granules during installation operation, which leads to disruption of the cleaning process. The signal about the end of the filter cycle is the indication of the pressure change in the tank 2, recorded using the device 40. To remove contaminants, a systematic regeneration of granular nozzles is necessary. To wash the nozzle in the coalescing chamber 18, the washing water is supplied to the housing 1 through a tee 25 with the valve 26 open. Before washing through the nozzle 31, compressed air is introduced into the housing 1 to increase the volume of the granular nozzle and facilitate washing with water. During the washing process, the solid impurities washed from the granules together with the water are removed through the tee 28 with the valve 29 open. To wash the auxiliary nozzle from randomly spilled solid particles, the washing water is fed through the central pipe 9 with the valve 36 open and discharged through the tee 28 with the valve 29 open.

 When the unit is in operation, a high degree of wastewater treatment (up to 99.5%) is obtained from both petroleum products and solid impurities. A high degree of purification from oil products is achieved through the use of a magnetohydrodynamic inductor in it, which provides for the reduction of the level of wastewater stabilization, the use of a water distribution chamber in which the water flow is evenly distributed over the housing cross section and the precipitation of large solid impurities, as well as through the intensification of the process for separating oil product droplets from granules at the interface: oil - water as a result of the creation of a contact oil medium. A high degree of purification from solid impurities is achieved due to their double deposition - first in the water distribution chamber, and then in the coalescing chamber.

 The filter cycle of the installation is significantly increased due to the fact that the regeneration of granular nozzles is carried out only from solid impurities, since oil products are removed from the nozzles of the installation during the cleaning process, and also due to the fact that part of the solid impurities is removed from the water at the initial period of its purification, not in contact with granules, through ajar valve 30, or before flushing.

Claims (1)

 Installation for wastewater treatment from oil products and solid impurities, including a cylindrical body with a cover and a pipe installed in its upper part for the removal of oil products, pipes for entering the wastewater into the body and cleaning it, as well as a coalescing chamber located inside the housing, a sump and an additional purification chamber, characterized in that it is equipped with a device located at the inlet of the wastewater into the housing to reduce its stability, made in the form of a magneto-hydrodynamic inductor, as well as containers for wastewater and purified water connected to the housing with pipes for the input of wastewater and cleaned water, mounted on them, the latter being located below the pipe for the removal of oil products, the housing is equipped with a lower hydrophobic, middle hydrophilic and upper hydrophobic perforated partitions, as well as a central pipe with a glass mounted on it, made with a conical bottom and with an internal hydrophilic partition and forming a gap with the upper partition, a coalescing chamber is enclosed between days and the middle partitions, the sump and the additional cleaning chamber are between the middle and upper partitions, the latter is installed below the oil discharge pipe and is movably connected to the housing cover, and its lower part is made in connection with a cylinder of a smaller diameter with the formation of a water distribution chamber.