A refinery initial stormwater collection and treatment system

Abstract

The application discloses a kind of oil refining enterprises initial rainwater collection and processing system, it is related to initial rainwater runoff processing technical field, including rainwater collection system, oil removal system and multistage soil infiltration system connected in turn;The rainwater collection system is used to deliver the sewage collected to oil removal system;Grid is equipped on the water delivery path in the rainwater collection system;Coarse granulation oil removal zone and oil-water separation zone are equipped in the oil removal system, and the sewage delivered by the rainwater collection system sequentially passes through coarse granulation oil removal zone and oil-water separation zone;The multistage soil infiltration system includes plant layer;The oil-water separation zone is used to deliver the sewage remaining after separating oil pollution to the plant layer.Form a kind of physical-chemical-ecological combined processing system, can realize the complementary of single process, fill the blank of oil refining enterprises initial rainwater pollution.

Description

Technical Field

[0001] This invention relates to the field of initial rainwater runoff treatment technology, specifically to an initial rainwater collection and treatment system for oil refineries. Background Technology

[0002] Initial runoff refers to rainwater collected at the beginning of rainfall, generally consisting of 10-15 mm of surface runoff. Directly discharging this initial runoff into rivers and lakes will cause severe water pollution. This is because the initial runoff washes over the ground and buildings, coming into contact with suspended particulate matter, nitrogen oxides, sulfur oxides, and other pollutants in the air, dissolving large amounts of these substances. Initial runoff from surface runoff is a non-point source pollutant, with a wide range and deep impact. Therefore, the management of initial runoff is of significant practical importance for effectively controlling pollutants entering rivers and lakes and for environmental beautification.

[0003] Currently, urban initial stormwater management methods mainly include source control, stormwater storage, and end-of-pipe treatment. Due to the immaturity of technologies such as green roofs, permeable pavements, and stormwater storage, my country's stormwater treatment technology still primarily relies on end-of-pipe treatment. Urban initial stormwater is characterized by large volumes, short accumulation periods, and rapid changes in water quality. Urban wastewater treatment plants lack sufficient capacity to handle this initial stormwater, and the processes at ordinary wastewater treatment plants are not suitable for handling large volumes of it.

[0004] In recent years, with the rapid rise of sponge cities, my country has developed a relatively sound approach and system for end-of-pipe treatment of urban initial rainwater pollution. However, the discharge of initial rainwater from factories and enterprises has remained largely unaddressed. The characteristics of urban initial rainwater vary by region, and the water quality of the initial rainwater from polluted rivers also differs. This is mainly related to regional population distribution, industrial layout, pollution interception and treatment levels, and the level of urban development. The pollutants in the initial rainwater from oil refineries mainly come from gravel particles on the ground within the enterprise, oil spills from the refinery, and discarded garbage. The pollutants carried are not entirely the same as those in rainwater from urban residential areas. In addition to conventional COD, nitrogen, and phosphorus, the initial rainwater discharged from oil refineries also contains a large amount of oil spills generated from leaks and spills within the enterprise. When initial rainwater from oil refineries enters local sewage treatment plants through sewer pipes or is directly discharged into rivers, it can cause shock loads to local sewage treatment plants and even lead to significant pollution. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention aims to provide an initial rainwater collection and treatment system for oil refineries, forming a combined physical-chemical-ecological treatment system that can complement the advantages and disadvantages of individual processes, thus filling the gap in addressing initial rainwater pollution in oil refineries.

[0006] This invention is achieved through the following technical solution:

[0007] A rainwater collection and treatment system for an oil refinery includes a rainwater collection system, an oil removal system, and a multi-stage soil infiltration system connected in sequence.

[0008] The rainwater harvesting system is used to transport the collected wastewater to the oil removal system; the water conveyance path in the rainwater harvesting system is equipped with a screen;

[0009] The oil removal system includes a coarse oil removal zone and an oil-water separation zone, and the wastewater transported by the rainwater collection system passes through the coarse oil removal zone and the oil-water separation zone in sequence.

[0010] The multi-stage soil infiltration system includes a vegetation layer;

[0011] The oil-water separation zone is used to transport the remaining wastewater after oil separation to the plant layer.

[0012] Compared to existing technologies, the pollutants in the initial rainwater discharged from oil refineries mainly come from gravel particles on the ground inside the refinery, oil spills from the refinery, and garbage discarded by the factory. The pollutants carried by this rainwater are not entirely the same as those in urban residential rainwater. In addition to conventional COD, nitrogen, and phosphorus, the initial rainwater discharged from oil refineries also contains a large amount of oil pollution generated by leaks and spills within the enterprise. The initial rainwater from oil refineries enters the local sewage treatment plant through the sewer pipes or is directly discharged into the river, which can cause shock loads to the local sewage treatment plant and even cause major pollution problems. This invention provides an initial rainwater collection and treatment system for oil refineries. This solution forms a physical-chemical-ecological combined treatment system, which can achieve the complementary advantages and disadvantages of single processes and fill the gap in the initial rainwater pollution of oil refineries.

[0013] The specific plan includes an initial rainwater collection system with grates along its water delivery path to isolate large debris and other materials, preventing them from interfering with subsequent wastewater treatment processes. The collected wastewater is then fed into an oil removal system with a coarse-graining oil removal zone. This coarse-graining process involves passing oily wastewater through a device filled with a coarse-grained material. As the wastewater flows through this material, oil droplets in the wastewater increase in size, making them easier to remove by gravity separation, while the wastewater itself, including its oil content and the properties of the oil, remains unchanged. After coarse-graining oil removal, the wastewater enters an oil-water separation zone, where oil and water are separated by gravity. The remaining wastewater after oil separation is then transported to a plant layer. This plant layer, growing on a substrate layer, primarily cultivates pollution-tolerant plants, including reeds, water onions, lotus, and Vallisneria natans. Some suspended particulate matter, nitrogen, and phosphorus in the wastewater are intercepted and adsorbed by plants in this layer, which can also remove COD from the wastewater, thus achieving ecological pollution removal.

[0014] In the above scheme, initial rainwater is collected through a rainwater harvesting system. However, if too much rainwater is collected at once, it will put a large water load on the subsequent sewage treatment device. Therefore, to control the amount of initial rainwater collected, the rainwater harvesting system is configured as follows: the rainwater harvesting system includes a collector, and the collector is equipped with a float chamber. The top of the float chamber has an inlet, and the float chamber contains a float with a diameter larger than the inlet. In this scheme, the rainwater harvesting system has a float chamber, and the float chamber contains a float. The upper inlet of the float chamber can be similar to a conical opening. The density of the float in the float chamber is less than the density of sewage, and the diameter of the float is larger than the diameter of the conical opening. After rainfall begins, the initial rainwater enters the rainwater harvesting system through the inlet. The float installed in the float chamber will rise as the water level in the rainwater harvesting system rises, eventually blocking the inlet and completing the collection of the initial rainwater runoff.

[0015] Furthermore, to prevent impurities from entering the subsequent wastewater treatment device, the following configuration is provided: the outlet of the rainwater collection system is connected to the inlet of the oil removal system via a connecting pipe, the inlet of the oil removal system being higher than the outlet of the rainwater collection system, and a lift pump being installed in the connecting pipe; in this scheme, the outlet of the rainwater collection system can be located in the middle of the float chamber to prevent impurities settled at the bottom of the float chamber from being drawn into the oil removal system and subsequently extracted by the lift pump.

[0016] Furthermore, as a specific implementation of an oil removal system, it is configured as follows: the oil removal system includes an inlet distribution zone, a coarse-grained oil removal zone, and an oil-water separation zone connected in sequence. The inlet distribution zone is used to distribute wastewater to the coarse-grained oil removal zone. The oil-water separation zone has several anti-short-flow plates, which are staggered to form a bend channel. The oil-water separation zone transports wastewater to the multi-stage soil infiltration system through the bend channel. The bend channel has a wastewater inlet connected to the coarse-grained oil removal zone at its upper end and a wastewater outlet connected to the multi-stage soil infiltration system at its lower end. In this scheme, the wastewater transported by the rainwater harvesting system first enters the inlet distribution zone, and then enters the coarse-grained oil removal zone, causing the oil droplets in the wastewater to enlarge. The wastewater then enters the oil-water separation zone for oil removal. Within this zone, a horizontally positioned tank ensures horizontal flow of the wastewater. Inside, several staggered anti-short-flow plates are installed, meaning the plates are parallel to each other. In a pair of adjacent anti-short-flow plates, one end connects to one side of the tank's interior, leaving a gap between the other end and the other side. Similarly, the other anti-short-flow plate connects to the other side of the tank's interior, leaving a gap between one end and one side. This bend in the flow path prevents short-flow of wastewater and allows for thorough horizontal separation of grease and water. In the oil-water separation zone, gravity causes the oil to rise to the surface, where it is separated in the oil collection area. The concentrated oil is then sent to the local wastewater treatment plant for further treatment, while the remaining wastewater enters a multi-stage filtration system through the effluent area.

[0017] Furthermore, to extract the separated oil sludge, an oil collector is provided at the top of the oil-water separation zone. The oil collector is used to extract the oil sludge from the liquid surface of the oil-water separation zone. Preferably, the oil collector is located at the top of the tank at the end of the bend channel. The oil sludge that has accumulated at the liquid surface after separation is extracted and sent to the local sewage treatment plant for treatment through the oil sludge outlet.

[0018] Furthermore, as a specific implementation of the coarse-grained oil removal zone, it is configured as follows: the coarse-grained oil removal zone includes a porous packing coalescence zone; the bottom of the porous packing coalescence zone has a first gravel bearing layer; in this scheme, the coarse-grained oil removal zone includes the upper porous packing coalescence zone and the first gravel bearing layer for supporting the porous packing coalescence zone, wherein the coarse-grained material in the porous packing coalescence zone is often granular material as packing, such as ceramsite filter media, anthracite filter media, walnut shell filter media, fiber ball filter media, and quartz sand filter media.

[0019] Furthermore, the first gravel bearing layer includes a first gravel layer, a second gravel layer, and a third gravel layer arranged sequentially from top to bottom. The first gravel layer uses gravel with a diameter of 4-8 mm; the second gravel layer uses gravel with a diameter of 8-16 mm; and the third gravel layer uses gravel with a diameter of 16-32 mm.

[0020] Furthermore, to ensure that wastewater enters the plant layer evenly, a water distribution device is provided above the plant layer. The water distribution device includes a spray pipe network, and the inlet of the spray pipe network is connected to the outlet of the oil removal system. In this scheme, the water inlet and distribution pipes in the soil infiltration system are distributed in the upper middle part of the plant layer above the system. The water distribution pipes are spray pipe networks with equidistant openings and several nozzles, which spray the wastewater into the plant layer.

[0021] Furthermore, to further reduce COD in the water, the multi-stage soil infiltration system includes a soil layer located below the plant layer, wherein polyurethane foam is mixed within the soil layer. In this scheme, the soil layer below the plant layer mainly consists of the original soil, but other materials can also be mixed with the soil. This equipment uses polyurethane foam mixed with the soil. Polyurethane foam is an inexpensive porous material that can adsorb organic matter and heavy metals in wastewater. Simultaneously, residual oil and recalcitrant organic matter in the wastewater are decomposed by microorganisms in the soil at this layer, reducing COD in the water.

[0022] Furthermore, the multi-stage soil infiltration system also includes an impermeable layer located below the soil layer, with a second gravel support layer below the impermeable layer; the lower layer of the soil layer is the impermeable layer, mainly composed of clay and the like. The bottom layer of the soil infiltration system is a gravel layer, which supports the entire system and also allows for drainage; the initial rainwater treated by the infiltration system can be directly discharged into the surrounding environment of the enterprise through the clean water outlet at the bottom.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] 1. This invention provides an initial rainwater collection and treatment system for oil refineries. The rainwater collection system can effectively collect initial rainwater through the installation of float chambers and other devices, and will not collect excess rainwater, thus avoiding a large water load on the water treatment device.

[0025] 2. This invention provides an initial rainwater collection and treatment system for oil refining enterprises. The oil separator uses a coarse-graining method for treatment and utilizes the gravity difference between oil and water for oil-water separation. It does not require the addition of chemical agents, is small in size, has simple steps, high efficiency, and low investment.

[0026] 3. This invention provides an initial rainwater collection and treatment system for oil refineries, which uses soil infiltration to purify wastewater. This not only purifies wastewater efficiently but also improves the greening level of the enterprise, allowing the wastewater treatment equipment to blend with the natural landscape of the enterprise.

[0027] 4. This invention provides an initial rainwater collection and treatment system for oil refineries. The soil layer in the soil infiltration system is usually mixed with other materials. The soil is improved by mixing polyurethane foam with the soil. The porosity of the foam improves the soil's permeability and enhances the soil's removal efficiency of organic matter and heavy metals from wastewater, saving manpower and resources.

[0028] 5. This invention provides an initial rainwater collection and treatment system for oil refining enterprises. The oil-water separation zone is equipped with a short-circuit prevention plate to prevent sewage short-circuiting, while allowing oil and water to be fully separated by horizontal flow.

[0029] 6. This invention provides an initial rainwater collection and treatment system for oil refineries. The plants such as water onions planted in the soil infiltration system have a good interception, absorption and adsorption effect on heavy metals, nitrogen and phosphorus in the water, and can improve the physical and chemical properties of the underlying soil. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0031] Figure 1 A schematic diagram of the structure of an initial rainwater collection and treatment system for an oil refinery, according to an embodiment of the present invention;

[0032] Figure 2 This is a cross-sectional schematic diagram of the oil-water separation zone according to an embodiment of the present invention.

[0033] The attached diagram shows the markings and corresponding component names:

[0034] 1-Float chamber, 2-Float, 3-Lift pump, 4-Inlet water distribution area, 5-Porous packing coalescing area, 6-First gravel layer, 7-Second gravel layer, 8-Third gravel layer, 9-Oil-water separation area, 10-Oil collector, 11-Oil outlet, 12-Outlet pipe, 13-Water distribution device, 14-Plant layer, 15-Soil layer, 16-Imperible layer, 17-Second gravel bearing layer, 18-Clean water outlet, 19-Support, 20-Anti-shortage plate, 21-Sewage inlet, 22-Sewage outlet. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0036] Example 1: This Example 1 provides a system for collecting and treating initial rainwater in an oil refinery, such as... Figure 1 and Figure 2 As shown, it includes a rainwater harvesting system, an oil removal system, and a multi-stage soil infiltration system connected in sequence;

[0037] The rainwater harvesting system is used to transport the collected wastewater to the oil removal system; the water conveyance path in the rainwater harvesting system is equipped with a screen;

[0038] The oil removal system is equipped with a coarse oil removal zone and an oil-water separation zone 9. The wastewater transported by the rainwater collection system passes through the coarse oil removal zone and the oil-water separation zone 9 in sequence.

[0039] The multi-stage soil infiltration system includes a plant layer 14;

[0040] The oil-water separation zone 9 is used to transport the remaining wastewater after oil separation to the plant layer 14.

[0041] Compared to existing technologies, the pollutants in the initial rainwater discharged from oil refineries mainly come from gravel particles on the ground inside the refinery, oil spills from the refinery, and garbage discarded by the factory. The pollutants carried by this rainwater are not entirely the same as those in urban residential rainwater. In addition to conventional COD, nitrogen, and phosphorus, the initial rainwater discharged from oil refineries also contains a large amount of oil pollution generated by leaks and spills within the enterprise. The initial rainwater from oil refineries enters the local sewage treatment plant through the sewer pipes or is directly discharged into the river, which can cause shock loads to the local sewage treatment plant and even cause major pollution problems. This invention provides an initial rainwater collection and treatment system for oil refineries. This solution forms a physical-chemical-ecological combined treatment system, which can achieve the complementary advantages and disadvantages of single processes and fill the gap in the initial rainwater pollution of oil refineries.

[0042] The specific plan includes an initial rainwater collection system with a screen along its water delivery path to isolate large debris and other materials, preventing them from affecting subsequent wastewater treatment processes. The collected wastewater is then fed into an oil removal system with a coarse-graining oil removal zone. This coarse-graining process involves passing oily wastewater through a device filled with a coarse-graining material. As the wastewater flows through this material, the oil droplets in the wastewater increase in size, making them easier to remove by gravity separation, while the wastewater itself, including its oil content and the properties of the oil, remain unchanged. After coarse-graining oil removal, the wastewater enters an oil-water separation zone 9, where it separates oil and water by gravity. The remaining wastewater after oil separation is then transported to a plant layer 14, which grows on the substrate layer and primarily cultivates pollution-resistant plants, including reeds, water onions, lotus, and Vallisneria natans. Some suspended particulate matter, nitrogen, and phosphorus in the wastewater are intercepted and adsorbed by plants in this layer, which can also remove COD from the wastewater, thus achieving ecological pollution removal.

[0043] In the above scheme, initial rainwater is collected through a rainwater harvesting system. However, if too much rainwater is collected at once, it will put a large water load on the subsequent sewage treatment device. Therefore, to control the amount of initial rainwater collected, the rainwater harvesting system is configured as follows: the rainwater harvesting system includes a collector, and the collector is equipped with a float chamber 2. The top of the float chamber 2 has an inlet, and the float 2 is installed inside. The diameter of the float 2 is larger than the size of the inlet. In this scheme, the rainwater harvesting system has a float chamber 2, and the float 2 is installed inside the float chamber 2. The upper inlet of the float chamber 2 can be similar to a conical opening. The density of the float 2 inside the float chamber 2 is less than the density of sewage, and the diameter of the float 2 is larger than the diameter of the conical opening. After rainfall begins, the initial rainwater enters the rainwater harvesting system through the inlet. The float 2 installed in the float chamber 2 will rise with the rise of the water level in the rainwater harvesting system, and finally block the inlet, completing the collection of the initial rainwater runoff.

[0044] In this embodiment, to prevent impurities from entering the subsequent sewage treatment device, the outlet of the rainwater collection system is connected to the inlet of the oil removal system via a connecting pipe. The inlet of the oil removal system is higher than the outlet of the rainwater collection system, and a lift pump 3 is provided in the connecting pipe. In this scheme, the outlet of the rainwater collection system can be located in the middle of the float 2 chamber to prevent impurities settled at the bottom of the float 2 chamber from being drawn into the oil removal system and then extracted by the lift pump 3.

[0045] In this embodiment, as a specific implementation of an oil removal system, the system comprises an inlet distribution zone 4, a coarse-grained oil removal zone, and an oil-water separation zone 9 connected in sequence. The inlet distribution zone 4 distributes wastewater to the coarse-grained oil removal zone. The oil-water separation zone 9 has several anti-short-flow plates 20, which are staggered to form a bend in the flow channel. The oil-water separation zone 9 transports wastewater to the multi-stage soil infiltration system through the bend in the flow channel. The bend in the flow channel has a wastewater inlet 21 connected to the coarse-grained oil removal zone at its upper end and a wastewater outlet 22 connected to the multi-stage soil infiltration system at its lower end. In this scheme, the wastewater transported by the rainwater harvesting system first enters the inlet distribution zone 4, and then enters the coarse-grained oil removal zone through the inlet distribution zone 4, causing the oil droplets in the wastewater to become larger. The wastewater then enters the oil-water separation zone 9 for oil removal. Within this zone, a horizontally placed tank is used to ensure horizontal flow of the wastewater. Inside, several staggered anti-short-flow plates 20 are installed, meaning these plates are parallel to each other. In two adjacent anti-short-flow plates 20, one end connects to one side of the tank's interior, leaving a gap between the other end and the other side. Similarly, the other end of the anti-short-flow plate 20 connects to the other side of the tank's interior, leaving a gap between one end and one side. This bend in the channel prevents short-flow of wastewater and allows for thorough horizontal separation of grease and water. Within the oil-water separation zone 9, gravity causes the oil to rise and separate in the oil collection area. The concentrated oil is then fed into the local wastewater treatment plant for further treatment, while the remaining wastewater enters a multi-stage filtration system through the effluent area.

[0046] In this embodiment, to extract the separated oil sludge, an oil collector 10 is provided at the top of the oil-water separation zone 9. The oil collector 10 is used to extract the oil sludge from the liquid surface of the oil-water separation zone 9. Preferably, the oil collector 10 is located at the top of the tank at the end of the bend channel. The oil sludge that has accumulated at the liquid surface after separation is extracted and sent to the local sewage treatment plant for treatment through the oil sludge outlet 11.

[0047] In this embodiment, as a specific implementation of the coarse-grained oil removal zone, it is configured as follows: the coarse-grained oil removal zone includes a porous packing coalescence zone 5; the bottom of the porous packing coalescence zone 5 has a first gravel bearing layer; in this scheme, the coarse-grained oil removal zone includes the upper porous packing coalescence zone 5 and the first gravel bearing layer for supporting the porous packing coalescence zone 5, wherein the coarse-grained material in the porous packing coalescence zone 5 is often granular material as packing, such as ceramsite filter media, anthracite filter media, walnut shell filter media, fiber ball filter media, and quartz sand filter media.

[0048] In this embodiment, the first gravel bearing layer includes a first gravel layer 6, a second gravel layer 7, and a third gravel layer 8 arranged sequentially from top to bottom. The first gravel layer 6 uses gravel with a diameter of 4-8 mm; the second gravel layer 7 uses gravel with a diameter of 8-16 mm; and the third gravel layer 8 uses gravel with a diameter of 16-32 mm.

[0049] In this embodiment, to ensure that wastewater enters the plant layer 14 evenly, a water distribution device 13 is provided above the plant layer 14. The water distribution device 13 includes a spray pipe network, and the inlet of the spray pipe network is connected to the outlet of the oil removal system. In this scheme, the water inlet and distribution pipes in the soil infiltration system are distributed in the upper middle part of the plant layer 14 above the system. The water distribution pipes are spray pipe networks with equidistant openings and several nozzles, which spray water into the plant layer 14.

[0050] In this embodiment, to further reduce COD in the water, the multi-stage soil infiltration system includes a soil layer 15 located below the plant layer 14, wherein polyurethane foam is mixed within the soil layer 15. In this scheme, the soil layer 15 lies below the plant layer 14, primarily comprising the original soil, but other materials can also be mixed with it. This device uses polyurethane foam to mix with the soil. Polyurethane foam is an inexpensive porous material that can adsorb organic matter and heavy metals in wastewater. Simultaneously, residual oil and recalcitrant organic matter in the wastewater are decomposed by microorganisms in the soil at this layer, reducing COD in the water.

[0051] In this embodiment, the multi-stage soil infiltration system further includes an impermeable layer 16 located below the soil layer 15, and a second gravel support layer 17 below the impermeable layer 16; the impermeable layer 16 is located below the soil layer 15 and is mainly composed of clay and the like. The bottom layer of the soil infiltration system is a gravel layer, which supports the entire system and also allows for drainage; the initial rainwater treated by the infiltration system can be directly discharged into the surrounding environment of the enterprise through the clean water outlet 18 at the bottom.

[0052] Example 2: This Example 2 provides a specific implementation method, such as... Figure 1 and Figure 2 As shown, Figure 1This is a rainwater collection and treatment system for an oil refinery. The diagram illustrates the basic structure and main components of the system. Both the inlet and outlet pipes have a diameter of 10-12 cm. The initial rainwater runoff is calculated based on a 10 mm thick surface runoff layer. Taking a petrochemical company as an example, with a total area of ​​12.7 million square meters, the total rainwater treatment capacity is 127,000 m³, completed in 24 hours, with an inlet flow rate of 5291.7 m³ / h. The designed length, width, and height of the rainwater collection system are 3m, 4m, and 2m, respectively. The diameter of the float 2 in the rainwater collection system should be larger than the diameter of the inlet, and the material should be any non-toxic material with a density less than water. Anthracite is used as the coarsening material in the oil separator's coarsening stage, with a wetting angle of 13°18′. The gravel particle sizes in the lower support layer, from top to bottom, are 4-8 mm, 8-16 mm, and 16-32 mm, respectively. The outer casing of the oil removal device is made of corrosion-resistant carbon steel. The volume ratio of anthracite to gravel is 4:1, and the volume ratio of gravel of three different particle sizes within the gravel layer is 1:1:1. Oil-water separation zone 9 uses a corridor-style structure for horizontal flow separation, saving space in the oil separator and ensuring thorough separation of grease and wastewater. In the soil infiltration system, the water distribution system uses 5cm diameter water pipes, with openings every 15cm for spraying wastewater. The soil infiltration system is 2m long, 2m wide, and 1m high. Soil layer 15 consists of soil and polyurethane foam; the foam boards are shredded into fine particles, washed with tap water, and then uniformly mixed with the soil at a 1:1 volume ratio. The impermeable layer 16 is made of clay, and the drainage layer consists of gravel with a particle size of 8-16mm. The height ratio of soil layer 15, impermeable layer 16, and drainage layer is 8:3:2.

[0053] Figure 2 The structure of the oil-water separation zone 9 of the oil separator, namely Figure 1 The structure is marked with number 9. Wastewater mixed with oil enters the oil-water separation zone 9 from the inlet. In the oil-water separation zone 9, the water flows horizontally, and the grease floats to the surface of the water due to gravity. It is then sucked into the pipe through the oil collector 10 and discharged. The remaining wastewater enters the soil infiltration system from the outlet.

[0054] Implementation Case:

[0055] (1) Taking a petrochemical company as an example: the total area is 12.7 million square meters, the total amount of rainwater to be treated is 127,000 m³, the treatment is completed in 24 hours, and the inflow rate is 5291.7 m³ / h. Multiple initial rainwater collection and treatment devices can be set up according to the actual size of the company's land area. The rainwater collection system is built underground, with a length, width and height of 3m, 4m and 2m respectively. When the area where the company is located begins to receive rainfall, the collection system begins to collect initial rainwater, and the float 2 rises with the rise of the liquid level in the collection system. When the float 2 rises to the rainwater inlet position, the rainwater collection ends. (2) Rainwater enters the oil separator through the water lift pump 3. The oil separator is installed above ground next to the rainwater collection system. Rainwater is distributed in the inlet distribution area of ​​the oil separator so that the sewage enters the coarsening zone evenly. (3) In the coarsening zone, the rainwater first passes through the anthracite material. When the oily wastewater passes through the bed filled with agglomerated material, the oil particles are captured by the material and retained on the surface and in the pores of the material. As the number of captured oil particles increases, the oil particles will deform and merge into larger oil particles, which are easier to separate into oil and water in the later stage. (4) In the oil-water separation zone 9, the coarsened wastewater is separated by gravity, the oil layer is separated by the oil collector 10, and the remaining wastewater is evenly introduced into the soil infiltration system through the water distribution system. (5) In the soil infiltration system, the wastewater first passes through the plant layer 14, and the plant intercepts, adsorbs and decomposes some of the suspended particulate matter, nitrogen and phosphorus and a small amount of COD in the water. The wastewater infiltrates into the soil layer 15. In the soil layer 15, the upper soil layer is basically in an aerobic state, and the organic matter in the water is decomposed by microorganisms in an aerobic state. The lower soil layer is basically in an anaerobic state, and some difficult-to-degrade organic matter in the water is decomposed in an anaerobic state. At the same time, the ammonia nitrogen in the water is removed by nitrification and denitrification under the alternating action of aerobic and anaerobic. The polyurethane foam mixed in the soil adsorbs organic matter, heavy metals and other substances in the water. (6) The seepage prevention layer 16 in the system is mainly composed of clay, which can enhance the dispersion of water, prevent blockage and enhance air circulation. (7) The purified water is discharged into the natural soil through a drainage layer made of gravel.

[0056] This invention relates to a system for collecting and treating initial rainwater from oil refineries. It combines a collection system, an oil removal system, and a soil infiltration system, enabling operation in an environment without human intervention. The system performs multi-level interception, adsorption, and decomposition of suspended particulate matter, COD, nitrogen and phosphorus, and oil pollution in the initial rainwater from oil refineries. Furthermore, this wastewater treatment system has a small footprint, low energy consumption, and requires no chemical additives, making it suitable for the intermittent and scattered discharge characteristics of initial rainwater from oil refineries.

[0057] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A system for collecting and treating initial rainwater in an oil refinery, characterized in that, It includes a rainwater harvesting system, an oil removal system, and a multi-stage soil infiltration system connected in sequence; The rainwater harvesting system is used to transport the collected wastewater to the oil removal system; the water conveyance path in the rainwater harvesting system is equipped with a screen; The oil removal system is provided with a coarse oil removal zone and an oil-water separation zone (9), and the sewage transported by the rainwater collection system passes through the coarse oil removal zone and the oil-water separation zone (9) in sequence. The multi-stage soil infiltration system includes a plant layer (14). The oil-water separation zone (9) is used to transport the remaining wastewater after oil separation to the plant layer (14). The coarse-grained degreasing zone includes a porous packing coalescing zone (5), the bottom of which has a first gravel bearing layer; The first gravel bearing layer includes a first gravel layer (6), a second gravel layer (7) and a third gravel layer (8) arranged sequentially from top to bottom. The first gravel layer (6) uses gravel with a diameter of 4-8 mm; the second gravel layer (7) uses gravel with a diameter of 8-16 mm; and the third gravel layer (8) uses gravel with a diameter of 16-32 mm.

2. The initial rainwater collection and treatment system for oil refineries according to claim 1, characterized in that, The rainwater harvesting system includes a collector, which has a float chamber (1) inside. The float chamber (1) has an inlet at the top and a float (2) inside. The diameter of the float (2) is larger than the size of the inlet.

3. The initial rainwater collection and treatment system for oil refineries according to claim 1, characterized in that, The outlet of the rainwater collection system is connected to the inlet of the oil removal system via a connecting pipe. The inlet of the oil removal system is higher than the outlet of the rainwater collection system. A booster pump (3) is installed in the connecting pipe.

4. The initial rainwater collection and treatment system for an oil refinery according to claim 1, characterized in that, The oil removal system includes an inlet distribution zone (4), a coarse-grained oil removal zone, and an oil-water separation zone (9) connected in sequence. The inlet distribution zone (4) is used to distribute sewage to the coarse-grained oil removal zone. The oil-water separation zone (9) is equipped with several anti-short-flow plates (20). The anti-short-flow plates (20) are staggered to form a bend channel. The oil-water separation zone (9) transports sewage to the multi-stage soil infiltration system through the bend channel. The bend channel has a sewage inlet (21) connected to the coarse-grained oil removal zone at the top and a sewage outlet (22) connected to the multi-stage soil infiltration system at the bottom.

5. The initial rainwater collection and treatment system for an oil refinery according to claim 1, characterized in that, The top of the oil-water separation zone (9) is also provided with an oil collector (10), which is used to extract oil from the surface of the oil-water separation zone (9).

6. The initial rainwater collection and treatment system for an oil refinery according to claim 1, characterized in that, A water distribution device (13) is provided above the plant layer (14). The water distribution device (13) includes a spray pipe network, and the inlet of the spray pipe network is connected to the outlet of the oil removal system.

7. The initial rainwater collection and treatment system for an oil refinery according to claim 1, characterized in that, The multi-stage soil infiltration system also includes a soil layer (15) located below the plant layer (14), the soil layer (15) being mixed with polyurethane foam.

8. A system for collecting and treating initial rainwater in an oil refinery according to claim 7, characterized in that, The multi-stage soil infiltration system also includes an impermeable layer (16) located below the soil layer (15), and a second gravel bearing layer (17) is located below the impermeable layer (16).

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