Refining sludge source reduction and classification treatment process and system

Abstract

The invention belongs to the technical field of sewage treatment, and provides a refining sludge source reduction and classification treatment process and system.The process comprises the steps that sewage is pretreated to obtain a first liquid phase and a first solid phase, and then the first liquid phase is separated to obtain a second liquid phase and a second solid phase; introducing the second liquid phase into a sewage treatment device to obtain a third liquid phase and a third solid phase, then discharging the third liquid phase, and carrying out concentration treatment and dehydration treatment on the third solid phase to obtain a fourth liquid phase and a fourth solid phase; and sequentially carrying out demulsification treatment and dehydration treatment on the first solid phase and the second solid phase to obtain a fifth liquid phase and a fifth solid phase. The sludge source is treated, solid substances in the separated liquid phase are separated for multiple times, the finally discharged clear liquid is collected and utilized, the purification efficiency of the three kinds of sludge is improved, the reduction rate of the refined sludge is increased, meanwhile, the separated three kinds of sludge are dried and incinerated, and pollution is reduced.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and specifically relates to a process and system for reducing and classifying sludge at the source of refining. Background Technology

[0002] Refining sludge, scum from flotation units, and bottom sludge from oil separators / storage tanks are major types of solid waste in the petrochemical industry. Proper disposal of these three types of sludge is a major concern in the petrochemical industry. Refining and chemical enterprises have conducted considerable production practices and research and development on how to properly handle these sludges. Current technologies for treating oily sludge mainly include physicochemical treatment, thermal treatment, biological treatment, and comprehensive utilization technologies. However, as a common problem in the industry, the treatment of these three types of sludge still lacks reliable and effective methods. Currently, there is a need to construct a new model for reducing and treating refinery sludge, lowering energy consumption and carbon emissions in sludge treatment, and further improving the sludge reduction rate in refining and chemical industries.

[0003] In recent years, many methods for treating oily sludge have emerged, including solvent extraction, chemical thermal washing, microbial methods, and incineration. However, due to their high cost, inability to recover crude oil, and tendency to cause secondary pollution, these methods have not been widely adopted. Summary of the Invention

[0004] To address the problems in the background art, this invention proposes a process and system for reducing and classifying refining sludge at its source.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A process for reducing and classifying refining sludge at its source includes the following steps:

[0007] Wastewater is pretreated to obtain a first liquid phase and a first solid phase;

[0008] Separation steps: The first liquid phase is separated to obtain a second liquid phase and a second solid phase;

[0009] The second liquid phase is passed into the wastewater treatment device to obtain the third liquid phase and the third solid phase. Then the third liquid phase is discharged and the third solid phase is concentrated and dehydrated to obtain the fourth liquid phase and the fourth solid phase.

[0010] The first and second solid phases were subjected to demulsification and dehydration treatments in sequence to obtain a fifth liquid phase and a fifth solid phase.

[0011] Collect the fourth and fifth liquid phases and return them to the separation step for further processing;

[0012] The fourth and fifth solid phases were dried, incinerated, and landfilled.

[0013] Further, the wastewater is pretreated to obtain a first liquid phase and a first solid phase, including the following steps:

[0014] Wastewater from the crude oil tank is discharged into the sedimentation tank via an automatic water cutter, and wastewater from the electro-desalination unit is discharged into the sedimentation tank;

[0015] Wastewater is separated in a sedimentation tank to obtain a first solid phase, which is then transported to a demulsification and oil removal device; and the wastewater separated in the sedimentation tank is sequentially transported to a separation device to obtain a first liquid phase;

[0016] The first liquid phase is transported to the oil separator.

[0017] Further, the first liquid phase is separated to obtain a second liquid phase and a second solid phase, including the following steps:

[0018] The first liquid phase is sequentially passed into an oil separator and an air flotation device, and after separation, a second liquid phase and a second solid phase are obtained.

[0019] Further, the second liquid phase is passed into the wastewater treatment device to obtain a third liquid phase and a third solid phase, and then the third liquid phase is discharged, including the following steps:

[0020] The second liquid phase is passed into an anaerobic / aerobic tank for microbial treatment, and then into a secondary sedimentation tank for sedimentation treatment to obtain a third liquid phase and a third solid phase.

[0021] The third liquid phase is discharged.

[0022] Furthermore, the anaerobic / aerobic tanks and secondary sedimentation tanks were replaced with sequencing batch activated sludge tanks.

[0023] Further, the third solid phase is concentrated and dehydrated to obtain a fourth liquid phase and a fourth solid phase, including the following steps:

[0024] The third solid phase is passed into a concentration tank for concentration treatment, and then passed into a centrifugal dehydrator for dehydration to obtain a fourth liquid phase and a fourth solid phase;

[0025] The fourth solid phase is transported to the sludge storage tank, and the fourth liquid phase is transported to the wastewater tank.

[0026] Further, the first and second solid phases are subjected to demulsification and dehydration treatments in sequence to obtain a fifth liquid phase and a fifth solid phase, including the following steps:

[0027] The first and second solid phases are demulsified and deoiled using a demulsification and deoiling device, and then conveyed to a dehydrator.

[0028] The first and second solid phases after demulsification and oil removal are dehydrated using a dewatering machine, and then the resulting fifth solid phase is transported to a sludge storage tank.

[0029] The fifth liquid phase obtained from demulsification, oil removal, and dehydration treatments was collected.

[0030] Further, the fourth and fifth liquid phases are collected and returned to the separation step for processing, including the following steps:

[0031] The fourth and fifth liquid phases were collected into the wastewater tank;

[0032] The fourth and fifth liquid phases in the wastewater tank are introduced into the oil separator.

[0033] Furthermore, the fourth and fifth solid phases are dried, incinerated, and landfilled, including the following steps:

[0034] The fourth and fifth solid phases are passed into a drying machine for drying.

[0035] The dried fourth and fifth solid phases are then passed into an incinerator for combustion.

[0036] The fourth and fifth solid phases after incineration will be transported to landfills.

[0037] A system for reducing and classifying refining sludge at its source, comprising:

[0038] The pretreatment unit is used to pretreat wastewater to obtain a first liquid phase and a first solid phase;

[0039] The first processing unit is used to separate the first liquid phase to obtain a second liquid phase and a second solid phase;

[0040] The second processing unit is used to pass the second liquid phase into the wastewater treatment device to obtain a third liquid phase and a third solid phase, and then discharge the third liquid phase, and to concentrate and dehydrate the third solid phase to obtain a fourth liquid phase and a fourth solid phase.

[0041] The third processing unit is used to sequentially demulsify and dehydrate the first solid phase and the second solid phase to obtain the fifth liquid phase and the fifth solid phase.

[0042] The fourth processing unit is used to collect the fourth and fifth liquid phases and return them to the first processing unit for further processing.

[0043] The fifth processing unit is used to dry, incinerate, and landfill the fourth and fifth solid phases.

[0044] The beneficial effects of this invention are:

[0045] 1. This invention treats sludge at its source by separating solids from the liquid phase multiple times and collecting and utilizing the final discharged clear liquid, thereby improving the purification efficiency of the three types of sludge and increasing the reduction rate of refining sludge. In addition, this invention also dries and incinerates the separated three types of sludge, reducing pollution.

[0046] 2. This invention effectively reduces the oil content of wastewater by discharging it into an automatic water cutter. At the same time, it uses physical methods to pre-treat high-concentration oily wastewater such as wastewater from crude oil tank area water cutting and electro-desalting, thereby improving the oil recovery rate and resource utilization level.

[0047] 3. This invention uses an oil separator to precipitate the liquid phase to produce bottom sludge, and then uses an air flotation device to chemically treat the liquid phase to produce scum. The scum and bottom sludge are then treated by a demulsification and oil removal process, which further improves the oil recovery rate and reduces the oil content of the sludge, creating favorable conditions for subsequent sludge drying. This solves the safety problem of thermal drying of oil sludge that is common in refining and chemical enterprises, and achieves safe reduction of refining and chemical sludge.

[0048] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This invention presents a general flow chart of a process for reducing and classifying refining sludge at its source according to the present invention;

[0051] Figure 2 A flowchart of the first refining sludge source reduction and classification treatment process of the present invention is shown;

[0052] Figure 3 A framework diagram of a refining sludge source reduction and classification treatment system according to the present invention is shown. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Example 1

[0055] A process for reducing and classifying refining sludge at its source, such as Figure 1 As shown, it includes the following steps:

[0056] S1: The wastewater is pretreated to obtain a first liquid phase and a first solid phase.

[0057] S2: Separate the first liquid phase to obtain the second liquid phase and the second solid phase.

[0058] S3: The second liquid phase is introduced into the wastewater treatment device to obtain the third liquid phase and the third solid phase. Then the third liquid phase is discharged, and the third solid phase is concentrated and dehydrated to obtain the fourth liquid phase and the fourth solid phase.

[0059] S4: Simultaneously with S3, the first and second solid phases are sequentially demulsified and dehydrated to obtain the fifth liquid phase and the fifth solid phase.

[0060] S5: Collect the fourth and fifth liquid phases and return them to S2 for processing.

[0061] S6: Dry, incinerate, and landfill the fourth and fifth solid phases.

[0062] It should be noted that the S1-S6 processes are based on source control of the three types of sludge, and are designed to treat refinery wastewater from different sources. Firstly, an automatic water cutter is added to the crude oil tank drainage, one of the sources, to reduce oil discharge. This is then treated together with the drainage from the electrostatic precipitator. The drainage from the electrostatic precipitator undergoes physical demulsification and oil removal to reduce the oil content. After treatment, it is combined with the drainage from other units and discharged into the wastewater treatment plant for further treatment. The wastewater is treated through oil separators, flotation units, biological treatment tanks, and secondary sedimentation tanks before being discharged in compliance with standards. The bottom sludge, scum, and biological sludge generated from the oil separators, flotation units, and secondary sedimentation tanks are demulsified, dewatered, concentrated, and centrifuged before being mixed in a sludge storage tank. After mixing, the mixture is dried in a dryer and finally incinerated and transported off-site.

[0063] In some embodiments, the liquid phase is one or more of oily sludge, clear liquid, and wastewater; the solid phase is one or more of biochemical sludge, bottom sludge, and scum. Therefore, the treatment process varies significantly depending on the solid and liquid phases.

[0064] In some embodiments, the process equipment S1-S6 includes a drainage section, a wastewater treatment section, a sludge treatment section, and a storage section. The drainage section mainly consists of a crude oil tank, an electrostatic desalination unit, and other devices, and the crude oil tank can be connected to an automatic water cutter. The wastewater treatment unit, separation unit, and storage section may be modified accordingly depending on the process. The following description uses the S1-S6 process flow as an example.

[0065] In S1, different process equipment and procedures are used according to the needs of different solid phases. Figure 2 In this process, the demulsification and oil removal device can employ one or more of the following: chemical demulsification, physical demulsification, electrochemical demulsification, thermal washing demulsification, and chemical demulsification. The dewatering machine can be a screw press dewatering machine. The oil-water separation device mainly realizes one or more combinations of processes such as coalescence, flotation, and concentration. The wastewater treatment device can be a combination of conveying to an anaerobic / aerobic tank (A / O tank) and a secondary sedimentation tank, or a sequencing batch reactor (SBR) tank alone. The following description is based on Examples 2 and 3.

[0066] Example 2

[0067] Combination Figure 2 In one optional embodiment, S1 includes the following steps:

[0068] S101: Install an automatic water cutter on the crude oil tank to reduce the oil content of each drainage from the crude oil tank, and then discharge the wastewater to the sedimentation tank together with the electro-desalination unit.

[0069] S102: Solid-liquid separation of wastewater is carried out through sedimentation tank, and the separated bottom sludge (first solid phase) is discharged into demulsification and oil removal device.

[0070] S103: Operates synchronously with S102. It sequentially transports the wastewater separated in the sedimentation tank to the coalescing oil separator and the cyclone flotation device for oil removal and flotation treatment of the clear liquid and sludge (first liquid phase). Then, the sludge is transported (stored) to the sludge tank, while the clear liquid and sludge are transported to the oil separator.

[0071] It should be noted that sedimentation tanks, oil-coalescing separators, cyclone flotation devices, and sludge tanks are used in sections S101 to S103. The oil-coalescing separator and cyclone flotation device are separation devices that can separate oil and water, while the sludge tank is a storage component. The oil-coalescing separator utilizes the difference in interfacial tension between oil droplets and water droplets, causing them to spread to varying degrees on the surface of the coalescing material. Oil droplets are not wetted on the surface of the coalescing material and cannot spread, forming oil droplets that collide and coalesce into larger oil droplets, which are then separated from the water, effectively removing oil from the wastewater and improving water cleanliness. The cyclone flotation device further enhances the oil-water separation effect through the dual action of cyclone and flotation, further purifying the water. As for the sludge tank, it mainly serves as a storage device, collecting and storing the oil separated from the wastewater for subsequent treatment or recycling.

[0072] It should be noted that S1 mainly realizes the oil-water separation process, while the specific processes of S2 and S3 can adopt different schemes. They mainly demulsify and remove oil from sludge with high oil content, while wastewater with low oil content or no oil is treated by a wastewater treatment device. Examples 3 and 4 are given below for illustration.

[0073] Example 3

[0074] S2 includes the following steps:

[0075] After the first liquid phase enters the oil separator, it is allowed to settle and obtain bottom sludge. Then, the first liquid phase is passed into the air flotation device to generate scum. After that, the bottom sludge and scum (the second solid phase is bottom sludge and scum with high oil content) are transported to the demulsification and oil removal device. At the same time, the liquid phase after separating the bottom sludge (the second liquid phase) is transported to the anaerobic / aerobic tank (A / O tank).

[0076] S3 includes the following steps:

[0077] S301a: The liquid phase is introduced into the A / O tank for microbial treatment, then integrated into the secondary sedimentation tank for sedimentation treatment, and finally the liquid phase (third liquid phase) that meets the discharge requirements is discharged. S302a: The bottom sludge in the secondary sedimentation tank that does not require A / O treatment (third solid phase, low oil content) is transported to the thickening tank, while the sludge that requires A / O treatment is returned to the A / O tank for treatment.

[0078] It should be noted that in S301a to S302a, the A / O tank and the secondary sedimentation tank are wastewater treatment devices.

[0079] Example 4

[0080] In another alternative embodiment, the anaerobic / aerobic tank and secondary sedimentation tank are replaced with a sequencing batch reactor (SBR), wherein S2 includes the following steps:

[0081] After the first liquid phase enters the oil separator, it is allowed to settle and obtain bottom sludge. Then, the liquid phase is passed into the air flotation device to generate scum. After that, the bottom sludge and scum (the second solid phase with high oil content) are transported to the ultrasonic demulsifier. At the same time, the liquid phase after separating the bottom sludge (the second liquid phase) is transported to the sequencing batch reactor (SBR).

[0082] S3 includes the following steps;

[0083] S301b: The second liquid phase is introduced into the SBR tank (sewage treatment device) for microbial treatment, and then the liquid phase that meets the discharge requirements is discharged. S302b: The bottom sludge that does not require SBR treatment (the third solid phase, with low oil content) is sent to the thickening tank, while the sludge that requires SBR treatment is returned to the SBR tank for further treatment.

[0084] It should be noted that in Example 4, the SBR tank, namely the Sequencing Batch Reactor Activated Sludge Process, can effectively remove pollutants.

[0085] Example 5

[0086] like Figure 2 As shown, the bottom sludge is fed into a thickening tank for thickening treatment, and then fed into a centrifugal dewatering machine for dewatering, resulting in dewatered bottom sludge (fourth solid phase) and clear liquid (fourth liquid phase). The dewatered bottom sludge is then transported to a sludge storage tank, and the clear liquid is transported to a wastewater tank.

[0087] S4 then includes the following steps:

[0088] S401: The first and second solid phases are demulsified and deoiled by a demulsification and deoiling device, and then conveyed to a dewatering machine.

[0089] S402: The first and second solid phases after demulsification are dewatered by a dewatering machine, and the resulting fifth solid phase is then transported to a sludge storage tank.

[0090] S403: Collect the clear liquid (fifth liquid phase) obtained from demulsification and dehydration treatment into the wastewater tank.

[0091] It should be noted that in S401 to S403, the oil separator, ultrasonic demulsifier, and screw press dewatering machine constitute the wastewater treatment section, while the wastewater tank and sludge storage tank constitute the storage section. The dewatering machine effectively separates water and solids from the sludge, producing a dry solid product with low moisture content.

[0092] In S5, the following steps are included:

[0093] S501: Collect the fourth and fifth liquid phases into the wastewater tank;

[0094] S502: The fourth and fifth liquid phases in the wastewater tank are introduced into the oil separator.

[0095] S6 includes the following steps:

[0096] S501: The stored sediment (fourth solid phase and fifth solid phase) is sequentially fed into a dryer for drying treatment.

[0097] S502: The dried sediment is fed into an incinerator for incineration, and then landfilled after incineration.

[0098] It should be noted that both the dryer and the incinerator are sludge treatment components.

[0099] Example 6

[0100] exist Figure 2 In the process of sludge source reduction and classification treatment, the petroleum content of the wastewater will gradually change with the process flow. The following examples 1, 2, 3 and 5 illustrate this:

[0101] Step 1: After installing the pipeline-type automatic water cutter in the crude oil tank, the petroleum content in the crude oil tank drainage is approximately 800 mg / L; the petroleum content in the drainage from the electro-desalting unit is 2000 mg / L. Both are discharged into the sedimentation tank for adjustment along with the crude oil tank drainage. After adjustment, the resulting bottom sludge is transported to the demulsification and oil removal unit, and the supernatant is discharged into the wastewater tank for collection. At this point, the solid-liquid content is approximately 98%, which is treated together with the bottom sludge from the oil separator and the scum from the flotation unit. After sedimentation, the wastewater is discharged into the coalescing oil separator for oil removal treatment, and then into the cyclone flotation unit for flotation treatment. The sludge and floating oil generated during the treatment process are transported to the sludge tank for collection and then recycled. After treatment, the petroleum content in the wastewater is reduced to 400 mg / L. The wastewater is then discharged into the oil separator for treatment along with the drainage from other units. The petroleum content in the drainage from other units is approximately 80 mg / L.

[0102] Step 2: After the wastewater is mixed in the oil separator, the petroleum content is approximately 300 mg / L and the COD is approximately 600 mg / L. After treatment in the oil separator, it is discharged into the dissolved air flotation (DAF) tank. The effluent from the oil separator has a petroleum content of approximately 150 mg / L and a COD of approximately 150 mg / L. After treatment in the DAF tank, it is discharged into the A / O tank. The effluent from the DAF tank has a petroleum content of approximately 20 mg / L and a COD of approximately 15 mg / L. After treatment in the A / O tank, the wastewater is discharged into the secondary sedimentation tank for further treatment until it meets the discharge standards for external discharge.

[0103] Step 3: During the wastewater treatment process, the oil separator generates floating oil and bottom sludge. The floating oil is transported to the sludge tank for collection and subsequent refining. The bottom sludge, along with the scum generated in the flotation tank during wastewater treatment, is transported at a rate of approximately 1.25 t / h to an ultrasonic demulsifier for conditioning and deoiling. Before treatment, the three phases of the sludge are oil phase 2%, water phase 94%, and solid phase 4%. After treatment by the ultrasonic demulsifier, it is transported to a screw press dewatering machine for dewatering. After dewatering, the sludge volume is reduced to 0.25 t / h, and the three phases of the sludge are oil phase 2%, water phase 78%, and solid phase 20%. After dewatering, the solid phase is transported to the sludge storage tank.

[0104] Step 4: The amount of biochemical sludge produced by the secondary sedimentation tank is about 2.5 t / h, with a solid-liquid content of about 96%. It is transported to the thickening tank for thickening treatment. After thickening, the solid phase is transported to the centrifugal dewatering machine for dewatering treatment. After dewatering, the solid phase is transported to the sludge storage tank. The amount of sludge after dewatering is about 0.5 t / h, with a solid-liquid content of about 80%.

[0105] Step 5: The sludge in the sludge storage tank is transported to the dryer for drying. Before drying, the liquid content of the solid phase is about 80%, and after drying, the liquid content of the solid phase is about 30%. After drying, the solid phase is transported to the incinerator for incineration. After incineration, the solid phase indicators meet the landfill regulations and are transported to the landfill for disposal.

[0106] It should be noted that the supernatant generated during the sludge treatment process by the sedimentation tank, ultrasonic demulsifier, screw press dewatering machine, sludge storage tank, and centrifugal dewatering machine is uniformly discharged into the wastewater tank for collection and returned to the oil separator for reuse.

[0107] Example 7

[0108] exist Figure 2 In the process of sludge source reduction and classification treatment, the petroleum content of the wastewater will gradually change with the process flow. The following examples 1 / 2 / 4 and 5 illustrate this:

[0109] Step 1: After installing the pipeline-type automatic water cutter in the crude oil tank, the oil content in the crude oil tank effluent is approximately 600 mg / L. The oil content in the effluent from the electrostatic desalination unit is 500 mg / L, which is discharged into the sedimentation tank along with the crude oil tank effluent for adjustment. After adjustment, the resulting bottom sludge is transported to the demulsification and oil removal unit, and the supernatant is collected in the wastewater tank. At this point, the solid-liquid content is approximately 98%, which is treated together with the bottom sludge from the oil separator and the scum from the flotation unit. After sedimentation, the wastewater is discharged into the coalescing oil separator for oil removal, and then into the cyclone flotation unit for flotation treatment. The sludge and floating oil generated during the treatment process are transported to the sludge tank for collection and subsequent recycling. At this point, the oil content in the clear liquid is 300 mg / L, which is discharged into the wastewater treatment system along with the effluent from other units. The oil content in the effluent from other units is approximately 150 mg / L.

[0110] Step 2: After the wastewater is mixed in the oil separator, the petroleum content is approximately 250 mg / L and the COD is approximately 550 mg / L. After treatment in the oil separator, it is discharged into the dissolved air flotation (DAF) tank. The effluent from the oil separator has a petroleum content of approximately 180 mg / L and a COD of approximately 130 mg / L. After treatment in the DAF tank, it is discharged into the SBR reactor. The effluent from the DAF tank has a petroleum content of approximately 5 mg / L and a COD of approximately 13 mg / L. After treatment in the SBR reactor, the wastewater meets the discharge standards and is discharged externally.

[0111] Step 3: During wastewater treatment, the oil and sludge generated in the oil separator are collected. The oil is transported to a sludge tank for further refining. The sludge, along with the scum generated in the flotation tank, is transported at a rate of approximately 1.8 t / h to a coagulation thickener for concentration. Before concentration, the sludge's three-phase composition is 0.5% oil, 95.5% water, and 4% solids. After coagulation thickener treatment, it is transported to a screw press dewatering machine for dewatering. After dewatering, the sludge volume is reduced to 0.36 t / h, with the three-phase composition being 2% oil, 78% water, and 20% solids. After dewatering, the solids are transported to a sludge storage tank.

[0112] Step 4: The amount of biochemical sludge produced by the SBR tank in treating wastewater is about 3.0 t / h, with a solid-liquid content of about 96%. It is transported to the thickening tank for thickening treatment. After thickening, the solid phase is transported to the centrifugal dewatering machine for dewatering treatment. After dewatering, the solid phase is transported to the sludge storage tank. The amount of sludge after dewatering is about 0.6 t / h, with a solid-liquid content of about 80%.

[0113] Step 5: The sludge in the sludge storage tank is transported to the dryer for drying. Before drying, the liquid content of the solid phase is about 80%, and after drying, the liquid content of the solid phase is about 30%. After drying, the solid phase is transported to the incinerator for incineration. After incineration, the solid phase indicators meet the landfill regulations and are transported to the landfill for disposal.

[0114] It should be noted that the clear liquid generated during the sludge treatment process by the above-mentioned demulsification and oil removal device, screw press dewatering machine, sludge storage tank, and centrifugal dewatering machine is uniformly discharged into the sewage tank for collection and returned to the oil separator for reuse.

[0115] It should be noted that, in embodiment 7, S1 can also adopt the following scheme:

[0116] After installing a pipeline-type automatic water cutter in the crude oil tank, the petroleum content in the tank effluent is approximately 600 mg / L. The petroleum content in the effluent from the electrostatic desalination unit is 500 mg / L, which, along with the crude oil tank effluent, is discharged into a high-efficiency tubular coagulation thickener. Three chemicals are added simultaneously to complete the coagulation and flocculation treatment. After treatment, the high-concentration scum at the top of the thickener is transported to a screw conveyor sludge dewatering machine, while the clear liquid at the bottom of the thickener is discharged into a centrifugal flotation tank. The scum is dewatered by the screw conveyor sludge dewatering machine, and the dewatered scum is transported to the coagulation thickener. The filtrate is discharged into the centrifugal flotation tank. The clear liquid and filtrate are separated by the centrifugal flotation tank, and the resulting scum is transported to a scum tank. The clear liquid is discharged into a clean water tank. At this point, the petroleum content in the clear liquid is 300 mg / L, which is discharged into the wastewater treatment system along with the effluent from other units. The petroleum content in the effluent from other units is approximately 150 mg / L.

[0117] Example 8

[0118] A source reduction and sorting treatment system for refining sludge, such as Figure 3As shown, the system includes a pretreatment unit, a first treatment unit, a second treatment unit, a third treatment unit, and a fourth treatment unit. The pretreatment unit pretreats the wastewater to obtain a first liquid phase and a first solid phase. The first treatment unit separates the first liquid phase to obtain a second liquid phase and a second solid phase. The second treatment unit introduces the second liquid phase into the wastewater treatment device to obtain a third liquid phase and a third solid phase, then discharges the third liquid phase and performs concentration and dehydration treatments on the third solid phase to obtain a fourth liquid phase and a fourth solid phase. The third treatment unit sequentially demulsifies and dehydrates the first and second solid phases to obtain a fifth liquid phase and a fifth solid phase. The fourth treatment unit collects the fourth and fifth liquid phases and returns them to the first treatment unit for further processing. The fifth treatment unit dries, incinerates, and landfills the fourth and fifth solid phases.

[0119] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for reducing and classifying refining sludge at its source, characterized in that, Includes the following steps: Wastewater is pretreated to obtain a first liquid phase and a first solid phase; Separation steps: The first liquid phase is separated to obtain a second liquid phase and a second solid phase; The second liquid phase is passed into the wastewater treatment device to obtain the third liquid phase and the third solid phase. Then the third liquid phase is discharged and the third solid phase is concentrated and dehydrated to obtain the fourth liquid phase and the fourth solid phase. The first and second solid phases were subjected to demulsification and dehydration treatments in sequence to obtain a fifth liquid phase and a fifth solid phase. Collect the fourth and fifth liquid phases and return them to the separation step for further processing; The fourth and fifth solid phases were dried, incinerated, and landfilled.

2. The process for reducing and classifying refining sludge at its source according to claim 1, characterized in that, Wastewater pretreatment to obtain a first liquid phase and a first solid phase includes the following steps: Wastewater from the crude oil tank is discharged into the sedimentation tank via an automatic water cutter, and wastewater from the electro-desalination unit is discharged into the sedimentation tank; Wastewater is separated in a sedimentation tank to obtain a first solid phase, which is then transported to a demulsification and oil removal device; and the wastewater separated in the sedimentation tank is sequentially transported to a separation device to obtain a first liquid phase; The first liquid phase is transported to the oil separator.

3. The process for reducing and classifying refining sludge at its source according to claim 1, characterized in that, The separation process of the first liquid phase to obtain a second liquid phase and a second solid phase includes the following steps: The first liquid phase is sequentially passed into an oil separator and an air flotation device, and after separation, a second liquid phase and a second solid phase are obtained.

4. The process for reducing and classifying refining sludge at its source according to claim 1, characterized in that, The second liquid phase is introduced into the wastewater treatment device to obtain a third liquid phase and a third solid phase, and then the third liquid phase is discharged, including the following steps: The second liquid phase is passed into an anaerobic / aerobic tank for microbial treatment, and then into a secondary sedimentation tank for sedimentation treatment to obtain a third liquid phase and a third solid phase. The third liquid phase is discharged.

5. The process for reducing and classifying refining sludge at its source according to claim 4, characterized in that, Replace the anaerobic / aerobic tanks and secondary sedimentation tanks with sequencing batch activated sludge tanks.

6. The process for reducing and classifying refining sludge at its source according to claim 5, characterized in that, The third solid phase is concentrated and dehydrated to obtain a fourth liquid phase and a fourth solid phase, including the following steps: The third solid phase is passed into a concentration tank for concentration treatment, and then passed into a centrifugal dehydrator for dehydration to obtain a fourth liquid phase and a fourth solid phase; The fourth solid phase is transported to the sludge storage tank, and the fourth liquid phase is transported to the wastewater tank.

7. The process for reducing and classifying refining sludge at its source according to claim 6, characterized in that, The first and second solid phases are subjected to demulsification and dehydration treatments in sequence to obtain a fifth liquid phase and a fifth solid phase, including the following steps: The first and second solid phases are demulsified and deoiled using a demulsification and deoiling device, and then conveyed to a dehydrator. The first and second solid phases after demulsification and oil removal are dehydrated using a dewatering machine, and then the resulting fifth solid phase is transported to a sludge storage tank. The fifth liquid phase obtained from demulsification, oil removal, and dehydration treatments was collected.

8. The process for reducing and classifying refining sludge at its source according to claim 1, characterized in that, Collect the fourth and fifth liquid phases and return them to the separation step for processing, including the following steps: The fourth and fifth liquid phases were collected into the wastewater tank; The fourth and fifth liquid phases in the wastewater tank are introduced into the oil separator.

9. The process for reducing and classifying refining sludge at its source according to claim 1, characterized in that, The fourth and fifth solid phases are dried, incinerated, and landfilled, including the following steps: The fourth and fifth solid phases are passed into a drying machine for drying. The dried fourth and fifth solid phases are then passed into an incinerator for combustion. The fourth and fifth solid phases after incineration will be transported to landfills.

10. A system for reducing and classifying refining sludge at its source, characterized in that, include: The pretreatment unit is used to pretreat wastewater to obtain a first liquid phase and a first solid phase; The first processing unit is used to separate the first liquid phase to obtain a second liquid phase and a second solid phase; The second processing unit is used to pass the second liquid phase into the wastewater treatment device to obtain a third liquid phase and a third solid phase, and then discharge the third liquid phase, and to concentrate and dehydrate the third solid phase to obtain a fourth liquid phase and a fourth solid phase. The third processing unit is used to sequentially demulsify and dehydrate the first solid phase and the second solid phase to obtain the fifth liquid phase and the fifth solid phase. The fourth processing unit is used to collect the fourth and fifth liquid phases and return them to the first processing unit for further processing. The fifth processing unit is used to dry, incinerate, and landfill the fourth and fifth solid phases.

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