RU2118197C1 - Plant for cleaning drainage water from mechanical impurities and petroleum products - Google Patents

Abstract

FIELD: petroleum and other industries. SUBSTANCE: partitions are mounted inside housing of settler in such way that thin layer of flow of liquid to be settled is created above upper edges of partitions. Settling of mechanical impurities is intensified through creating conditions for motion of liquid in compartments and spraying part of clean water above surface of liquid in settling compartments. EFFECT: enhanced efficiency of cleaning; intensification of cleaning process; possibility to control cleaning process. 1 dwg

Description

 The invention relates to wastewater treatment from mechanical impurities and oil products and can be used in any industry where such a need arises.

 For wastewater treatment, gravity sedimentation tanks in combination with hydrocyclones and flotation plants for cleaning oil products are usually used.

 A known apparatus for flotation wastewater treatment (AS USSR N 585125, class C 02 C 1/26, BI N 47, 1977), including a rough cleaning chamber with a pressureless hydrocyclone installed inside it and a flotation chamber made in series connected compartments.

 The disadvantage of this apparatus is that only rough cleaning of mechanical impurities with the help of a hydrocyclone is provided, and in the settling compartments the movement of the liquid against the settling particles does not allow small particles to settle and to further be cleaned of mechanical impurities.

 Closest to the proposed technical solution is an apparatus for oil dehydration (RF patent N 2077918, B 01 D 17/028, BI N 12, 1997), which includes a housing with a compartment for oil dehydration, a pipe supplying an oil-water mixture from one end of the housing and exhaust gases , water, oil, pipes, regulators of oil and water levels, transverse partitions in the middle of the section of the body, forming steps by the upper and lower edges of the partitions.

 The disadvantage of this apparatus in relation to wastewater treatment with a low content of oil products is that the stepwise placement of partitions along the upper edge of the partitions does not provide fluid overflow at the top of all partitions and the efficiency of the apparatus decreases.

 The objective is the efficient wastewater treatment with the lowest capital and operating costs.

 To solve this problem, in the known device, including a settling tank with partitions, a compartment for accumulating oil product, nozzles for supplying wastewater, drainage of purified water and oil product, regulators of the level of oil product and water, the upper edges of the partitions are located at the same level, while the penultimate partition is made blank from the bottom and forms a compartment for purified water, and the compartment for refined oil is formed by the last blind partition from below, the pipe for supplying wastewater is placed open end up at the bottom the edges of the first partition, and a pipe for draining purified water is located in the lower part of the sump in front of the last partition and is connected to a water seal, while a spray is placed in the upper part of the sump.

 Placing the partitions with the upper edges at the same level makes it possible to organize the movement of the purified water in a thin layer above the partitions, while the settling time of the mechanical impurities in the thin layer decreases sharply, the settling particles are delayed by the upper edge of the partitions and, in the direction of the passage to the clear water compartment, the mechanical impurities have time to settle thin layer. At the same time, fluid movement is organized in the compartments, which helps to accelerate the sedimentation of mechanical impurities. The input of wastewater above the lower edge of the first partition facilitates the movement of incoming wastewater above the partitions, while liquid from the compartments below the lower edges of the partitions flows from below, which accelerates the sedimentation of solids in the compartments, since the direction of water movement in the compartments coincides with the direction of motion of the settling particles .

 The presence of a spray that forms a shower of pure water above the surface of the compartments, where mechanical impurities are separated in a thin layer of wastewater, additionally accelerates the sedimentation of small mechanical impurities, as falling drops of water penetrate the liquid layer at a sufficient speed, entraining small particles of mechanical impurities.

 The drawing shows the installation containing the housing of the sump 1, baffle 2, baffle 3, forming a compartment for clean water, a baffle 4, forming a compartment for oil, inlet sewage pipe 5 with a valve 6, pipe 7 with a valve 8 for draining clean water, pipe 9 with a valve 10 for the removal of oil, a water lock 11, a pump 12, a valve 13 and a pipe 14, a valve 15 and a pipe 16, a sprayer 17, a pipe 18 with a valve 19 for removing sludge from the sump body.

 Installation works as follows.

 The installation according to the proposed scheme can be assembled and installed permanently or on a mobile chassis, depending on the characteristics of the facility and the amount of wastewater.

 Wastewater to be cleaned of mechanical impurities and oil is fed into the housing 1 of the sump through a pipe 5 with a valve 6 in the first compartment, i.e., in front of the first partition 2. The open end of the pipe 5 inside the sump is not lower than the lower edge of the first partition so so that the stream of supplied wastewater rises only in the first compartment. In this case, the rising jet still carries liquid from other compartments with it, causing the liquid to move downward in other compartments. Naturally, the magnitude of this speed will fall in subsequent compartments, starting from the second compartment. The rising wastewater in the first compartment further moves above the upper edges of the partitions 2 and 3 with a thin layer. The layer thickness easily changes depending on the size of the sump and the flow rate of wastewater. Sufficiently purified water from mechanical impurities, together with the petroleum product, enters the penultimate compartment behind the partition 3, where a constant level of the water-oil product interface is maintained by means of a water trap 11. When entering the compartment behind the partition 3, water passes through the hydrophobic layer of the oil product and is additionally cleaned of small mechanical impurities that are carried away with the oil product into the compartment behind the partition 4. From this compartment, the oil product is periodically removed as necessary through the pipe 9 with valves minutes 10. The purified water 12 is pumped through the conduit 14 with valve 13 for reuse or for other purposes. Part of the water after the pump 12 is taken through the pipe 16 with a valve 15 and is supplied to the spray gun 17 to form a shower above the compartments except the first and last two compartments. The supply of sprayed clean water above the compartments where sludge occurs further accelerates the sludge process, since falling water droplets in the upper layer of water in the sump increase the vertical velocity component and entrain the settling particles of mechanical impurities. The mechanical impurities accumulated in the sump are periodically removed by erosion through the pipe 18 with a valve 19.

 Thus, the proposed installation for the treatment of wastewater from mechanical impurities and oil products includes several factors that accelerate the sedimentation of mechanical impurities in the treated water and they can be changed over a wide range depending on the requirements for purified water. The number of partitions 2 can be quite large, if there is such a need, a change in the overall dimensions of the housing of the sump also greatly affects the degree of water purification. Water spraying is easily regulated by the position of the valve 15 opening and the pump power 12. The installation can work even in the absence of oil products in the waste water. In this case, the compartment for the accumulation of petroleum products will remain empty. The proposed installation, having ample opportunities for regulating the process, allows the purification of various wastewater to the required purity with the lowest capital and operating costs.

Claims (1)

 \\\ 1 Installation for the treatment of wastewater from mechanical impurities and oil products, including a settling tank with partitions, a compartment for accumulating oil products, pipes for supplying waste water, drainage of purified water and oil products, oil level and water level controllers, characterized in that the upper edges of the partitions are located at one level, while the penultimate partition is made blind from below and forms a compartment for purified water, and the purified oil compartment is formed by the last blind partition from below, a pipe for supplying wastewater placed open end up at the level of the lower edge of the first partition, and the pipe for the removal of purified water is located in the lower part of the sump in front of the last baffle and connected to a water seal, while in the upper part of the sump is placed a spray.