A treatment system and method for wastewater from refining and chemical integration

Abstract

The present invention discloses a treatment system and method for integrated refining and chemical wastewater, the treatment system comprising: a dissolved air flotation unit, used for desiliconizing and decontaminating the integrated refining and chemical homogeneous wastewater, and conveying the first wastewater after desiliconizing and decontaminating treatment to a ballast sedimentation unit; a ballast sedimentation unit, used for desiliconizing and decontaminating the first wastewater, and conveying the second wastewater after desiliconizing and decontaminating treatment to a filtration unit; a filtration unit, used for filtering the suspended solids in the second wastewater to obtain standard effluent. In this embodiment, the integrated refining and chemical wastewater is first desiliconized by the dissolved air flotation unit, and then the wastewater is desiliconized again in combination with the ballast sedimentation unit; thus, through the two-stage desiliconization treatment, the silicon content in the effluent of the treatment system can be easily reduced to below 15 mg / L, so that the treated effluent meets the standard discharge.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and in particular relates to a treatment system and a treatment method for refining-chemical integrated wastewater. Background Art

[0002] The production wastewater discharged from the ethylene and downstream deep processing units of the refining and chemical integration project mainly includes the wastewater discharged from the circulating water field, the chemical water treatment station, and the condensate treatment unit. The existing wastewater treatment system mainly uses the "high-efficiency dissolved air flotation tank + high-density sedimentation tank + filtration tank + dual-mode device" process to treat the production wastewater. However, the effluent treated by the wastewater treatment system still contains silicon, hardness and alkalinity, which cannot meet the high-quality recycled water quality indicators of the "Guidelines for the Management of Wastewater Reuse in Refining and Chemical Enterprises".

[0003] The existing wastewater treatment system removes silicon from the wastewater by adding magnesium oxide to the high-density sedimentation tank, and combines the sodium hydroxide / sodium carbonate double subtraction method in the high-density sedimentation tank to remove hardness from the wastewater. The existing process requires a large amount of magnesium agent to be added, and the silicon in the effluent is also unstable. The silicon in the effluent can only be treated to about 20 mg / L, and it is impossible to treat the silicon in the effluent lower; and the addition of magnesium agent causes a large amount of sludge to be generated by the wastewater treatment system. For this reason, it is urgently necessary to provide a new wastewater treatment system and treatment method to solve the problem that the existing treatment system has a large amount of sludge after treating wastewater and the effluent silicon cannot stably meet the standard. Summary of the invention

[0004] The present invention provides a treatment system and method for integrated refining and chemical wastewater, wherein the treatment system can effectively decontaminate the integrated refining and chemical wastewater, thereby reducing the silicon content in the effluent and the sludge discharge of the treatment system, thereby making the effluent meet standard discharge requirements.

[0005] To achieve the above-mentioned purpose, according to the first aspect of an embodiment of the present application, a treatment system for integrated refining and chemical wastewater is provided, the treatment system comprising: a dissolved air flotation unit, used to perform desiliconization and decontamination treatment on the integrated refining and chemical homogeneous wastewater, and convey the first wastewater after the desiliconization and decontamination treatment to a ballast sedimentation unit; a ballast sedimentation unit, used to perform desiliconization and sedimentation treatment on the first wastewater, and convey the second wastewater after the desiliconization and sedimentation treatment to a filtration unit; a filtration unit, used to filter the suspended solids in the second wastewater to obtain standard effluent.

[0006] To achieve the above-mentioned purpose, according to the second aspect of the embodiment of the present application, a method for treating wastewater from an integrated refining and chemical industry is further provided, the method comprising: homogenizing the production wastewater from the integrated refining and chemical industry through a wastewater regulating tank and then transporting it to a dissolved air flotation unit through a wastewater lifting pump according to a preset output volume; the dissolved air flotation unit performs desiliconization and decontamination treatment on the homogenized wastewater from the integrated refining and chemical industry, and transports the first wastewater after the desiliconization and decontamination treatment to a ballast sedimentation unit; the ballast sedimentation unit performs desiliconization and sedimentation treatment on the first wastewater, and transports the second wastewater after the desiliconization and sedimentation treatment to a V-type filter tank; the V-type filter tank filters the second wastewater, and transports the filtered wastewater to a water storage tank; the water storage tank collects and treats the filtered wastewater, and transports the collected wastewater to a membrane treatment device; the membrane treatment device performs deep treatment on the collected wastewater and outputs standard effluent.

[0007] Optionally, the ballast sedimentation unit includes: a first fast mixing tank, a second fast mixing tank, a flocculation tank, a sedimentation tank, and a cyclone; the ballast sedimentation unit performs a desiliconization sedimentation treatment on the first wastewater, and transports the second wastewater after the desiliconization sedimentation treatment to a V-type filter tank, including: the first fast mixing tank uses sodium hydroxide and sodium aluminate to remove silicon and hardness from a part of the wastewater output from the circular flotation tank to generate a third flocculent wastewater; and the third flocculent wastewater is transported to the second fast mixing tank; the third flocculent wastewater includes at least calcium carbonate floccules and aluminosilicate floccules; the second fast mixing tank uses soluble iron salts to treat the third flocculent wastewater; The floc wastewater is coagulated to obtain fourth floc wastewater; and the fourth floc wastewater is transported to a flocculation tank; the flocculation tank uses PAM and ballast to flocculate the fourth floc wastewater, and transports the fifth floc wastewater after flocculation to a sedimentation tank; the sedimentation tank performs sedimentation on the fifth floc wastewater, and transports the wastewater after sedimentation as the second wastewater to a V-type filter tank, and transports the sludge mixture with ballast after sedimentation to a cyclone device through a reflux pump; the cyclone device performs cyclone separation on the sludge mixture with ballast, and transports the separated ballast to the flocculation tank.

[0008] Optionally, the step of conveying the wastewater after sedimentation treatment as the second wastewater to a V-type filter tank comprises: adjusting the pH value of the wastewater after sedimentation treatment with an acid to obtain the second wastewater; the pH value of the second wastewater is 6-8; and conveying the second wastewater to a V-type filter tank.

[0009] Compared with the prior art, the embodiment of the present invention provides a treatment system and method for integrated refining and chemical wastewater, the treatment system comprising: a dissolved air flotation unit, used to perform silicon removal and decontamination treatment on the integrated refining and chemical homogeneous wastewater, and transport the first wastewater after the silicon removal and decontamination treatment to a ballast sedimentation unit; a ballast sedimentation unit, used to perform silicon removal and sedimentation treatment on the first wastewater, and transport the second wastewater after the silicon removal and sedimentation treatment to a filtration unit; a filtration unit, used to filter the suspended solids in the second wastewater to obtain standard effluent. In this embodiment, the integrated refining and chemical wastewater is first desiliconized by the dissolved air flotation unit, and then the wastewater is desiliconized again in combination with the ballast sedimentation unit; thus, through the two-stage desiliconization treatment, the silicon content in the effluent of the treatment system can be easily reduced to below 15 mg / L, so that the treated effluent meets the standard discharge. In addition, the ballasted sedimentation unit of this embodiment forms flocs with the ballast as the center. Therefore, when the ballasted sedimentation unit is used to precipitate the first wastewater, the ballast can increase the density of the alum flocs, thereby making the flocs more sedimentable, thereby improving the water quality of the effluent after sedimentation treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0011] Figure 1 A schematic diagram of the structure of a treatment system for wastewater from a refinery-chemical integration project provided by one embodiment of the present invention;

[0012] Figure 2 It is a structural schematic diagram of a dissolved air flotation unit in one embodiment of the present invention;

[0013] Figure 3 It is a structural schematic diagram of a ballast sedimentation unit in one embodiment of the present invention;

[0014] Figure 4 A schematic structural diagram of a system for treating wastewater from an integrated refinery and chemical industry according to another embodiment of the present invention. DETAILED DESCRIPTION

[0015] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0016] like Figure 1 As shown, it is a structural schematic diagram of a refining and chemical integrated wastewater treatment system provided by an embodiment of the present invention.

[0017] A treatment system for integrated refining and chemical wastewater, the treatment system comprising: a dissolved air flotation unit, used for performing desiliconization and decontamination treatment on the integrated refining and chemical homogeneous wastewater, and conveying the first wastewater after the desiliconization and decontamination treatment to a ballast sedimentation unit; a ballast sedimentation unit, used for performing desiliconization and sedimentation treatment on the first wastewater, and conveying the second wastewater after the desiliconization and sedimentation treatment to a filtration unit; a filtration unit, used for filtering suspended solids in the second wastewater to obtain standard effluent.

[0018] Specifically, the dissolved air flotation unit not only has the solid-liquid separation function of the conventional dissolved air flotation tank, but also has the function of removing silicon from wastewater. For example, the conventional dissolved air flotation tank has a large number of fine bubbles in the water, so that the air is attached to the suspended particles in the form of highly dispersed tiny bubbles, resulting in a state where the density is less than that of water, and the buoyancy principle is used to make it float on the water surface, thereby achieving solid-liquid separation.

[0019] Here, the dissolved air flotation unit may be a high-efficiency dissolved air flotation unit.

[0020] The ballast sedimentation unit not only has the function of a conventional high-efficiency sedimentation tank, but also has the function of removing silicon from wastewater. For example, a high-efficiency sedimentation tank is mainly used to achieve a certain degree of solid-liquid separation of turbid liquid in wastewater.

[0021] The filtration unit can filter and treat solid suspended matter of different particle sizes in the second wastewater, thereby achieving deep treatment of pollutants in the second wastewater and improving various indicators of the effluent from the treatment system, so that the effluent meets the high-quality recycled water quality indicators of the "Guidelines for Wastewater Reuse Management in Petroleum Refining and Chemical Enterprises".

[0022] This embodiment uses a dissolved air flotation unit and a ballast sedimentation unit to successively remove silicon from the integrated refining and chemical industry wastewater; thus, through two-stage silicon removal treatment, the silicon content in the effluent of the treatment system can be easily reduced to below 15 mg / L, so that the treated effluent meets the standard discharge. In addition, this embodiment uses a ballast sedimentation tank to perform sedimentation treatment on the first wastewater, which can increase the rising flow rate of the first wastewater to twice the existing rising flow rate, thereby improving the efficiency of the treatment system for the integrated refining and chemical industry wastewater treatment, thereby solving the problem of limited floor space of the existing treatment system.

[0023] In a preferred embodiment, Figure 2The figure is a schematic diagram of the structure of a dissolved air flotation unit in one embodiment of the present invention. The dissolved air flotation unit comprises: a coagulation tank for receiving the homogeneous wastewater of the integrated refinery and chemical industry, and using sodium aluminate as a coagulant to desiliconize the homogeneous wastewater; the fast mixing tank transports the first floc wastewater after the desiliconization treatment to the flocculation tank; wherein the first floc wastewater at least includes aluminosilicate flocs; the flocculation tank for flocculating the first floc wastewater with a flocculant, and transporting the second floc wastewater after the flocculation treatment to the circular flotation tank; the circular flotation tank for performing solid-liquid separation on the second floc wastewater, and transporting a part of the wastewater after the solid-liquid separation to the ballast sedimentation unit; the other part of the wastewater is pressurized and transported to the dissolved air tank by a dissolved air reflux pump; the dissolved air tank is used to perform pressurized dissolved air treatment on the other part of the wastewater, and transport the dissolved air water after the pressurized dissolved air treatment to the circular flotation tank.

[0024] Specifically, the output end of the coagulation tank is connected to the input end of the flocculation tank, the output end of the flocculation tank is connected to the input end of the circular flotation tank, and the output end of the circular flotation tank is connected to the input end of the dissolved air tank.

[0025] The homogeneous wastewater is transported to the coagulation tank, and sodium aluminate is added to the coagulation tank. After the coagulation tank is desiliconized, the first floc wastewater generated is transported to the flocculation tank; then, a flocculant is added to the flocculation tank, and after the flocculation tank is flocculated, the second floc wastewater generated is transported to the circular flotation tank; the circular flotation tank is used for solid-liquid separation to generate scum, sludge and wastewater; the scum is discharged, the sludge is discharged, and a part of the wastewater is transported to the ballast sedimentation unit; the other part of the wastewater is transported to the dissolved air tank; compressed air is input into the dissolved air tank, and the dissolved air tank performs pressurized dissolved air treatment on the other part of the wastewater based on the compressed air to generate dissolved air water; finally, the dissolved air tank returns the dissolved air water to the circular flotation tank.

[0026] It should be noted that sodium aluminate in the coagulation tank as a coagulant not only has a coagulation effect on homogeneous wastewater, for example, it can adsorb high-molecular pollutants in homogeneous wastewater; but also has a silicon removal effect on homogeneous wastewater, for example, sodium aluminate reacts with silicon in the wastewater to effectively generate small aluminosilicate flocs.

[0027] Here, the flocculant is polyacrylamide (PAM).

[0028] For example: adding sodium aluminate to the coagulation reaction tank to react with silicon in the homogenous wastewater can effectively generate small aluminosilicate flocs; then adding flocculant PAM to the flocculation tank, the small flocs are combined and enlarged by adding flocculants, thereby forming relatively large flocs in the flocculation tank; since the density of such large flocs is relatively small, they are more able to contact with microbubbles and adhere together through adhesion, forming aggregates with an average density less than that of water, thereby causing the aggregates to float to the surface of the tank body, and the treated wastewater sinks through the clear water area and is discharged to the circular flotation tank through multiple outlets at the bottom of the tank. Since the circular flotation tank uses reflux pressurized dissolved air flotation, after the second floc wastewater passes through the circular flotation tank for solid-liquid separation, part of the wastewater is transported to the ballast sedimentation unit, and the other part of the wastewater is further filtered through the pipeline filter, and then pressurized and transported to the dissolved air tank by the dissolved air reflux pump for pressurized dissolved air. The dissolved air water formed is transported to the circular flotation tank again. After entering the flotation tank, the dissolved air water releases a large number of tiny bubbles under the action of the sudden pressure drop and the specially designed pressure releaser, and adheres to the floc oil droplets, etc., and then floats to the surface of the circular flotation tank in the separation area, and finally discharges the scum through the negative pressure slag collection system. The heavier flocs will gather at the bottom of the circular flotation tank and then be discharged.

[0029] In this embodiment, sodium aluminate is added to the coagulation tank to convert silicon in the homogeneous wastewater into small aluminosilicate flocs, which are then treated by flocculation and a circular flotation tank to discharge most of the aluminosilicate salts out of the system in the form of scum or flocs, thereby reducing the silicon content in the effluent of the treatment system, thereby effectively controlling the silicon index of the effluent.

[0030] In a preferred embodiment, Figure 3The figure is a schematic diagram of the structure of a ballast sedimentation unit in one embodiment of the present invention. The ballast sedimentation unit comprises: a first rapid mixing tank, which is used to receive a portion of the wastewater from the circular flotation tank and then perform a silicon removal and hardness removal treatment using sodium hydroxide and sodium aluminate, and transport the third floc wastewater after the silicon removal and hardness removal treatment to a second rapid mixing tank; wherein the third floc wastewater at least includes aluminosilicate flocs and calcium carbonate flocs; a second rapid mixing tank, which is used to perform a coagulation treatment on the third floc wastewater using a soluble iron salt as a coagulant to obtain a fourth floc wastewater; and transport the fourth floc wastewater to a flocculation tank; a flocculation tank, which is used to perform a coagulant treatment on the third floc wastewater using a flocculant and a ballast The fourth floc wastewater is subjected to flocculation treatment, and the fifth floc wastewater after flocculation treatment is transported to a sedimentation tank; the sedimentation tank is used to perform sedimentation treatment on the fifth floc wastewater, and the wastewater after sedimentation treatment is transported to a filtration unit as the second wastewater; the sedimentation tank is also used to transport the sludge mixture with ballast after sedimentation treatment to a cyclone through a reflux pump; the cyclone is a cyclone device arranged above the flocculation tank; the cyclone is used to perform cyclone separation on the sludge mixture with ballast, and transport the separated ballast to the flocculation tank.

[0031] Specifically, the output end of the first fast mixing tank is connected to the input end of the second fast mixing tank; the output end of the second fast mixing tank is connected to the first input end of the flocculation tank, the output end of the flocculation tank is connected to the input end of the sedimentation tank, the first output end of the sedimentation tank is connected to the input end of the cyclone device, and the output end of the cyclone device is connected to the second input end of the flocculation tank.

[0032] It should be noted that the sodium aluminate in the first rapid mixing tank, as a coagulant, not only has a coagulation effect on the wastewater output from the circular flotation tank, for example, it can adsorb high molecular pollutants in the wastewater; but also has a silicon removal effect on the wastewater, for example, sodium aluminate reacts with silicon in the wastewater to effectively generate small aluminosilicate flocs.

[0033] The sodium hydroxide in the first rapid mixing tank adjusts the pH value of the wastewater to make the HCO 3 - CO generated by reaction with NaOH 3 2- Reacts with calcium in water to form CaCO 3 Sedimentation reduces the hardness of wastewater.

[0034] For example, part of the wastewater output from the circular flotation tank enters the ballast sedimentation unit. The wastewater first enters the first rapid mixing tank, and then NaOH and sodium aluminate are added to the rapid mixing tank to fully react to achieve the purpose of silicon removal and hardness removal. Since the added sodium hydroxide can adjust the pH value of the wastewater, the HCO in the wastewater 3 -Reacts with NaOH to generate CO 3 2- Reacts with calcium in water to form CaCO 3 Precipitation, while sodium aluminate continues to react with the remaining silicon in the wastewater to form aluminosilicate; then the third floc wastewater after the reaction enters the second rapid mixing tank 2, and by adding the coagulant ferric chloride in the second rapid mixing tank, iron hydroxide precipitation can be formed; since the formed iron hydroxide precipitation and calcium carbonate alum flocs are both heavier, they are easy to combine with aluminosilicate to form small flocs, which is conducive to sedimentation in the rear sedimentation tank, thereby reducing the aluminum content in the effluent of the treatment system. After that, a large number of small flocs enter the flocculation tank, with the ballast as the core, and with the assistance of the flocculant PAM, a large number of dense large alum flocs will be formed, and finally precipitated through the inclined tube to achieve the purpose of silicon removal and hardness removal. The sludge at the bottom of the final sedimentation tank is discharged through the sludge discharge pump, and part of the sludge and ballast are returned to the flocculation area through the ballast return pump. A cyclone device is installed above the flocculation tank, which can effectively separate the sludge and micro sand that are returned. The cyclone device cyclones the heavier ballast and enters the flocculation area for reuse. The cyclone-separated sludge is discharged into the sludge tank. Since the ballast will be partially lost, it is necessary to regularly add ballast to the flocculation tank.

[0035] In this embodiment, sodium aluminate in the first rapid mixing tank is used to coagulate the wastewater to generate relatively light small aluminosilicate flocs; then, the small aluminosilicate flocs are adsorbed by the iron hydroxide precipitate generated by the soluble iron salt in the second rapid mixing tank, thereby forming relatively heavy small flocs; finally, the small flocs are enlarged by the flocculation tank, and the enlarged flocs are precipitated by the sedimentation tank. Compared with magnesium oxide as a desiliconizing agent in the prior art, this embodiment uses sodium aluminate as a desiliconizing agent, which can reduce the amount of sludge in the treatment system of this application to 1 / 6-1 / 4 of the existing treatment system, thereby reducing the sludge discharge of the treatment system of this application. Moreover, this embodiment uses soluble iron salts as coagulants, which can effectively enhance the precipitation effect of flocs and ensure that the aluminum content of the effluent is lower.

[0036] In a preferred embodiment, Figure 4The figure shows a schematic diagram of the structure of a treatment system for wastewater from an integrated refinery and chemical industry provided by another embodiment of the present invention. A treatment system for wastewater from an integrated refinery and chemical industry comprises: a wastewater regulating tank, which is used to homogenize the production wastewater from the integrated refinery and chemical industry and then transport it to a dissolved air flotation unit through a wastewater lift pump according to a preset output volume; a high-efficiency dissolved air flotation unit, which is used to desiliconize and decontaminate the homogenized wastewater from the integrated refinery and chemical industry, and transport the first wastewater after the desiliconization and decontamination treatment to a ballast sedimentation unit; a ballast sedimentation unit, which is used to desiliconize and decontaminate the first wastewater and transport the second wastewater after the desiliconization and decontamination treatment to a V-type filter tank; a V-type filter tank; which is used to filter the second wastewater and transport the filtered wastewater to a water storage tank; a water storage tank, which is used to collect and treat the filtered wastewater and transport the collected wastewater to a membrane treatment device; a membrane treatment device, which is used to deeply treat the collected wastewater to obtain standard effluent.

[0037] Specifically, the output end of the wastewater regulating tank is connected to the input end of the dissolved air flotation unit, the output end of the dissolved air flotation unit is connected to the input end of the ballast sedimentation unit, the output end of the ballast sedimentation unit is connected to the input end of the V-type filter tank, the output end of the V-type filter tank is connected to the input end of the water storage tank, and the output end of the water storage tank is connected to the input end of the membrane treatment device.

[0038] The second wastewater output from the ballast sedimentation unit enters the V-type filter tank for filtration treatment, thereby removing suspended matter in the water. The side inlet trough of the V-type filter tank is designed to be V-shaped, and the effluent from the ballast sedimentation tank enters the V-type inlet trough from the water distribution channel. The water flows through the small holes at the bottom of the V-shaped trough and the overflow from the top of the trough, and evenly enters the filter tank, passes through the filter layer and the water distribution system to enter the bottom space, and then enters the clean water channel. After being collected, it enters the water storage tank. The wastewater collected by the water storage tank then enters the membrane treatment device, and is deeply treated based on the membrane treatment device. The output water meets the high-quality recycled water quality indicators of the "Guidelines for Wastewater Reuse Management in Refining and Chemical Enterprises".

[0039] Here, the structure of the dissolved air flotation unit of this embodiment is as follows: Figure 2 As shown, the structure of the ballast sedimentation unit is Figure 3 As shown, no repetition is made here.

[0040] Embodiment A method for treating refining-chemical integrated wastewater based on the refining-chemical integrated wastewater treatment system of the present application comprises at least the following steps:

[0041] Step 1: After the production wastewater of the integrated refining and chemical industry is homogenized through the wastewater regulating tank, it is transported to the coagulation tank of the high-efficiency dissolved air flotation unit through the wastewater lifting pump according to the preset output volume.

[0042] Step 2: The coagulation tank uses sodium aluminate to desiliconize the homogeneous wastewater of the integrated refining and chemical industry to generate aluminosilicate flocs; and the first floc wastewater containing aluminosilicate flocs is transported to the flocculation tank; the flocculation tank uses PAM to flocculate the first floc wastewater, and transports the second floc wastewater after flocculation to the circular flotation tank; the circular flotation tank performs solid-liquid separation on the second floc wastewater, and transports a part of the wastewater after solid-liquid separation to the first fast mixing tank of the ballast sedimentation unit; the other part of the wastewater is filtered and pressurized by a dissolved air reflux pump to a dissolved air tank; the dissolved air tank performs pressurized dissolved air treatment on the other part of the wastewater, and returns the dissolved air water after pressurized dissolved air treatment to the circular flotation tank.

[0043] Step 3: The first rapid mixing tank uses sodium hydroxide and sodium aluminate to remove silicon and hardness from a part of the wastewater output from the circular flotation tank to generate a third floc wastewater; and the third floc wastewater is transported to the second rapid mixing tank; the third floc wastewater at least includes calcium carbonate flocs and aluminosilicate flocs; the second rapid mixing tank uses soluble iron salts to coagulate the third floc wastewater to obtain a fourth floc wastewater; and the fourth floc wastewater is transported to the flocculation tank; the flocculation tank uses PAM and ballast to treat the fourth floc wastewater Flocculation treatment, and conveying the fifth floc wastewater after flocculation treatment to a sedimentation tank; the sedimentation tank performs sedimentation treatment on the fifth floc wastewater, and uses acid to adjust the pH value of the wastewater after sedimentation treatment to obtain a second wastewater; the pH value of the second wastewater is 6-8; the second wastewater is conveyed to a V-type filter tank, and the sludge mixture with ballast after sedimentation treatment is conveyed to a cyclone device through a reflux pump; the cyclone device performs cyclone separation on the sludge mixture with ballast, and conveys the separated ballast to the flocculation tank.

[0044] Step 4: The V-shaped filter tank filters the second wastewater and transports the filtered wastewater to a water storage tank.

[0045] Step 5: The water storage tank collects and processes the filtered wastewater and transports the collected wastewater to the membrane treatment device.

[0046] Step six, the membrane treatment device performs deep treatment on the collected wastewater and outputs standard effluent.

[0047] Comparative Example A method for treating refining-chemical integrated wastewater based on the prior art refining-chemical integrated wastewater treatment system, the method comprising at least the following steps:

[0048] Step 1: After the production wastewater of the integrated refining and chemical industry is homogenized through the wastewater regulating tank, it is transported to the coagulation tank of the high-efficiency dissolved air flotation tank through the wastewater lifting pump according to the preset output volume.

[0049] Step 2: The coagulation tank uses polyaluminum chloride (PAC) to coagulate the homogeneous wastewater of the integrated refining and chemical industry, and transports the first floc wastewater after coagulation treatment to the flocculation tank; the flocculation tank uses PAM to flocculate the first floc wastewater, and transports the second floc wastewater after flocculation treatment to the circular flotation tank; the circular flotation tank performs solid-liquid separation on the second floc wastewater, and transports a part of the wastewater after solid-liquid separation to the first fast mixing tank of the high-density sedimentation tank; the other part of the wastewater is filtered and pressurized by a dissolved air reflux pump to a dissolved air tank; the dissolved air tank performs pressurized dissolved air treatment on the other part of the wastewater, and returns the dissolved air water after pressurized dissolved air treatment to the circular flotation tank.

[0050] Step three: The first rapid mixing tank uses sodium hydroxide and magnesium oxide to remove silicon and hardness from a part of the wastewater output from the circular flotation tank to generate a third floc wastewater; and the third floc wastewater is transported to the second rapid mixing tank; the second rapid mixing tank uses PAC to coagulate the third floc wastewater to obtain a fourth floc wastewater; and the fourth floc wastewater is transported to the flocculation tank; the flocculation tank uses PAM to flocculate the fourth floc wastewater, and transports the fifth floc wastewater after flocculation to the sedimentation tank; the sedimentation tank performs sedimentation treatment on the fifth floc wastewater, and uses acid to adjust the pH value of the wastewater after sedimentation treatment to obtain the second wastewater; the pH value of the second wastewater is 6-8; the second wastewater is transported to the V-type filter tank, and the sludge at the bottom of the final sedimentation tank is discharged through the sludge discharge pump, and part of the sludge is returned to the flocculation tank to increase the concentration of the flocs in the flocculation tank, effectively increase the collision probability of small alum flowers, and save the dosage of flocculants.

[0051] Step 4: The V-shaped filter tank filters the second wastewater and transports the filtered wastewater to a water storage tank.

[0052] Step 5: The water storage tank collects and processes the filtered wastewater and transports the collected wastewater to the membrane treatment device.

[0053] Step six, the membrane treatment device performs deep treatment on the collected wastewater and outputs standard effluent.

[0054] The embodiment process of the method for treating the wastewater of the integrated refinery and chemical industry of the present application is as follows:

[0055] Table 1 Raw water information of production wastewater from refining and chemical integration in a refining and chemical project in Fujian

[0056]

[0057] Table 2 Specific parameters of various embodiments of the treatment system for integrated refining and chemical wastewater according to the present application

[0058]

[0059]

[0060] Table 3 Specific parameters of each comparative example of the treatment system of the integrated refining and chemical wastewater based on the prior art

[0061]

[0062]

[0063] Table 4 Specific parameters of each comparative example based on the treatment system of the integrated refining and chemical wastewater of this application

[0064]

[0065]

[0066] Table 5 Water output index of each embodiment and comparative example

[0067]

[0068] The following conclusions were drawn through the examples and comparative examples:

[0069] It can be concluded from Examples 1-3 that the two-stage addition of sodium aluminate for silicon removal has a very good effect in removing silicon and hardness, and can stably meet the standards. The mass ratio of the amount of sodium aluminate to the amount of silicon removed is between 1:0.8-1.2.

[0070] Through Examples 1-3 and Comparative Examples 1-3, it can be concluded that the use of magnesium oxide, according to the theoretical dosage of 10-15 times, cannot treat silicon below 15 mg / L, and the amount of sludge is very large, 4-6 times the amount of sludge in silicon removal with sodium aluminate.

[0071] It can be concluded from Example 3 and Comparative Examples 4-5 that when the same amount of sodium aluminate is added, the effect of adding sodium aluminate in the high-efficiency dissolved air flotation unit in one stage or in the secondary loading and precipitation unit is worse than that of adding in two stages.

[0072] It can be concluded from Examples 1-3 and Comparative Examples 6-7 that in order to meet the silicon content requirement of the effluent, if sodium aluminate is added in one stage for silicon removal, the dosage is much larger than that of two stages for silicon removal.

[0073] It can be seen that the present application changes the desiliconizing agent magnesium oxide / magnesium agent into sodium aluminate, which can effectively reduce the sludge production to about 1 / 4-1 / 6 of the existing sludge amount; the water quality of the effluent in the prior art is difficult to treat the silicon to below 15 mg / L due to the use of magnesium agent, while the silicon in the effluent of the present application can easily be reduced to below 15 mg / L; the present application changes the desiliconization in the prior art from the first-stage high-density sedimentation tank to a two-stage desiliconization by flotation and ballast sedimentation tank. The two-stage desiliconization not only improves the effluent quality but also saves the dosage of desiliconizing agent.

[0074] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0075] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0076] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0077] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0078] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

[0079] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0080] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0081] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A treatment system for wastewater from refining and chemical integration, It is characterized in that include: The dissolved air flotation unit is used to remove silicon and pollutants from the homogeneous wastewater of the refining and chemical integration, and transport the first wastewater after the silicon and pollutant removal treatment to the ballast sedimentation unit; A ballast sedimentation unit, used for performing a desiliconization sedimentation treatment on the first wastewater, and conveying the second wastewater after the desiliconization sedimentation treatment to a filtration unit; A filtering unit, used for filtering the suspended solids in the second wastewater to obtain standard effluent; The dissolved air flotation unit comprises: The coagulation tank is used to receive the homogeneous wastewater from the refining and chemical integration, and use sodium aluminate as a coagulant to desiliconize the homogeneous wastewater; the fast mixing tank transports the first floc wastewater after the desiliconization treatment to the flocculation tank; wherein the first floc wastewater at least includes aluminosilicate flocs; A flocculation tank, used for flocculating the first floc wastewater using a flocculant, and conveying the second floc wastewater after the flocculation treatment to a circular flotation tank; A circular flotation tank is used to separate the second flocculent wastewater into solid and liquid, and to transport a portion of the wastewater after solid-liquid separation to the ballast sedimentation unit; and the other portion of the wastewater is pressurized and transported to the dissolved air tank by a dissolved air reflux pump; A dissolved air tank is used to perform pressurized dissolved air treatment on the other part of the wastewater, and to transport the dissolved air water after the pressurized dissolved air treatment to the circular flotation tank; The ballast sedimentation unit comprises: The first rapid mixing tank is used to receive a portion of the wastewater from the circular flotation tank and perform silicon and hardness removal treatment using sodium hydroxide and sodium metaaluminate, and transport the third flocculent wastewater after silicon and hardness removal treatment to the second rapid mixing tank; wherein the third flocculent wastewater at least includes aluminosilicate flocs and calcium carbonate flocs; a second rapid mixing tank, for coagulating the third floc wastewater using soluble iron salt as a coagulant to obtain fourth floc wastewater; and transporting the fourth floc wastewater to a flocculation tank; a flocculation tank, used for flocculating the fourth floc wastewater using a flocculant and a ballast, and conveying the fifth floc wastewater after the flocculation treatment to a sedimentation tank; The sedimentation tank is used to perform sedimentation treatment on the fifth floc wastewater, and the wastewater after sedimentation treatment is transported to the filtering unit as the second wastewater.

2. The system according to claim 1, It is characterized in that The ballast sedimentation unit further comprises: a cyclone device disposed above the flocculation tank; The sedimentation tank is also used to transport the ballast-containing sludge mixture after sedimentation to the cyclone through a reflux pump; The cyclone device is used to perform cyclone separation on the sludge mixture with ballast, and transport the separated ballast to the flocculation tank.

3. The system according to claim 2, It is characterized in that The ballast is micro sand and / or garnet, and the flocculant is polyacrylamide PAM.

4. The system according to claim 1, It is characterized in that The filtration unit includes a V-shaped filtration tank, a water storage tank and a membrane treatment device; The V-shaped filter tank is used to filter the second wastewater and transport the filtered wastewater to the water storage tank; The water storage tank is used to collect and process the filtered wastewater and transport the collected wastewater to the membrane treatment device; The membrane treatment device is used to perform deep treatment on the collected wastewater to obtain standard effluent.

5. A method for treating wastewater from a refinery-chemical integration system using the system as claimed in any one of claims 1 to 4, It is characterized in that include: The production wastewater of the refining and chemical integration is homogenized through the wastewater regulating tank and then transported to the dissolved air flotation unit through the wastewater lifting pump according to the preset output volume; The dissolved air flotation unit performs desiliconization and decontamination treatment on the homogeneous wastewater of the refining and chemical integration, and transports the first wastewater after the desiliconization and decontamination treatment to the ballast sedimentation unit; The ballast sedimentation unit performs a desiliconization sedimentation treatment on the first wastewater, and transports the second wastewater after the desiliconization sedimentation treatment to the V-type filter tank; The V-shaped filter tank filters the second wastewater and transports the filtered wastewater to the water storage tank; The water storage tank collects and processes the filtered wastewater and transports the collected wastewater to the membrane treatment device; The membrane treatment device performs deep treatment on the collected wastewater and outputs standard effluent.

6. The method according to claim 5, It is characterized in that The dissolved air flotation unit includes: a coagulation tank, a flocculation tank, a circular flotation tank, and a dissolved air tank; the dissolved air flotation unit performs desiliconization and decontamination treatment on the homogeneous wastewater of the integrated refinery and chemical industry, and transports the first wastewater after desiliconization and decontamination treatment to the ballast sedimentation unit, including: The coagulation tank uses sodium aluminate to remove silicon from the homogeneous wastewater of the refinery integration to generate aluminosilicate flocs; and transports the first floc wastewater containing the aluminosilicate flocs to the coagulation tank; The flocculation tank uses PAM to flocculate the first floc wastewater, and transports the second floc wastewater after flocculation to the circular flotation tank; The circular flotation tank performs solid-liquid separation on the second flocculent wastewater, and transports a portion of the wastewater after solid-liquid separation to the ballast sedimentation unit; the other portion of the wastewater is filtered and pressurized by a dissolved air reflux pump and transported to a dissolved air tank; The gas dissolving tank performs pressurized gas dissolving treatment on the other part of the wastewater, and returns the gas-dissolving water after the pressurized gas dissolving treatment to the circular flotation tank.

7. The method according to claim 6, It is characterized in that The ballast sedimentation unit includes: a first fast mixing tank, a second fast mixing tank, a flocculation tank, a sedimentation tank, and a cyclone device; the ballast sedimentation unit performs desiliconization sedimentation treatment on the first wastewater, and transports the second wastewater after the desiliconization sedimentation treatment to the V-type filter tank, including: The first rapid mixing tank uses sodium hydroxide and sodium aluminate to remove silicon and hardness from a portion of the wastewater output from the circular flotation tank to generate third floc wastewater; and the third floc wastewater is transported to the second rapid mixing tank; the third floc wastewater includes at least calcium carbonate flocs and aluminosilicate flocs; The second rapid mixing tank uses soluble iron salt to perform coagulation treatment on the third floc wastewater to obtain fourth floc wastewater; and the fourth floc wastewater is transported to the flocculation tank; The flocculation tank uses PAM and ballast to flocculate the fourth floc wastewater, and transports the fifth floc wastewater after flocculation to the sedimentation tank; The sedimentation tank performs sedimentation treatment on the fifth flocculent wastewater, and transports the wastewater after the sedimentation treatment as the second wastewater to the V-type filter tank, and transports the sludge mixture with ballast after the sedimentation treatment to the cyclone device through a reflux pump; The cyclone device performs cyclone separation on the sludge mixture with ballast, and transports the separated ballast to the flocculation tank.

8. The method according to claim 7, It is characterized in that The method of transporting the wastewater after the sedimentation treatment as the second wastewater to the V-type filter tank comprises: Using an acid to adjust the pH value of the wastewater after the precipitation treatment to obtain a second wastewater; the pH value of the second wastewater is 6-8; The second wastewater is transported to a V-type filter tank.

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