Physico-chemical hot washing process for oily sludge

Abstract

The application discloses a physical-chemical hot washing process for oily sludge, and relates to the technical field of oily sludge treatment. The process comprises the following steps: preliminary separation of oily sludge in a rough washing section, storage of separated oil in a waste oil recovery tank, and discharge of the remaining oily sludge into a fine washing section; secondary washing and separation of the oily sludge in the fine washing section, storage of separated oil in the waste oil recovery tank, and discharge of the remaining oily sludge into a rinsing section; addition of clean water into the rinsing section to rinse the oily sludge, complete separation of waste oil, storage of the separated oil in the waste oil recovery tank, and discharge of separated water and sludge into a sedimentation section; addition of a flocculating agent into the sedimentation section to make suspended matters in the water sink, discharge of the separated water and sludge into a filter press, solid-liquid separation of the water and sludge by the filter press, discharge of the separated water into a waste water recovery tank, and discharge of the separated sludge into a sludge recovery tank. The process realizes three-phase separation of oil, water and sludge, has low oil content after separation, good separation effect, low cost, high efficiency and environmental protection and no pollution.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oily sludge treatment, and particularly relates to a physical-chemical hot washing process for oily sludge. BACKGROUND

[0002] Oily sludge refers to sludge mixed with crude oil, oil residue, various finished oil and other heavy oil. Oily sludge does not exist in nature. It is mainly formed by mixing water, soil and other pollutants in the process of oil development, refining, processing, transportation and production. In particular, oily sludge in oil fields has been listed as hazardous solid waste (HW08) by the state and is managed as hazardous waste. Oily sludge is produced in large quantities in the oil industry. If not properly treated, it will pollute the surrounding environment. The water content of oily sludge in oil fields is generally 70% to 99%, and the oil and salt content is high. The composition of oily sludge can be roughly divided into water, emulsified oil or adsorbed oil, solid foreign matter, inorganic salt, etc. Before harmless treatment, it needs to be reduced in volume to reduce the volume of oily sludge. With the increasing demand for oil resources worldwide, the production of oily sludge is also increasing, and people's awareness of environmental protection and sustainable development is also increasing. How to control the pollution of oily sludge to the environment has become an important problem for the petrochemical industry.

[0003] At present, oily sludge treatment and disposal technologies are developing rapidly. Various oily sludge treatment methods such as conditioning-separation, chemical hot washing, pyrolysis and incineration have been applied to oil and gas fields and refineries. However, the above-mentioned treatment methods have certain shortcomings. The conditioning-separation-sedimentation method has high water content and oil content in the treated sludge, which makes it difficult to meet the direct landfill requirements of the treated waste, so this method can only be used as a pretreatment method for oily sludge. The solvent extraction method is easy to operate continuously and remotely, and saves energy, but the equipment investment is too large and the cost is high. At present, the extraction method has not been widely used in the treatment of oily sludge in oil fields. The biological treatment method uses indigenous microorganisms for treatment. With the extension of time, the oil removal rate is higher and the degradation effect is more obvious, which can meet the emission standard. However, this method occupies a large area and takes a long time to treat. The incineration method is the most thorough method for treating oily sludge, but it requires a large investment and high treatment cost. It is easy to produce dioxin and other toxic substances, and complex flue gas purification measures are needed to increase the treatment cost. SUMMARY

[0004] The present application mainly aims to provide a physical-chemical hot washing process for oily sludge, which has good separation effect, low cost, high efficiency and is environmentally friendly and pollution-free, and can realize resource utilization, so as to solve the technical problems in the prior art.

[0005] To solve the above technical problems, the present application adopts the following technical scheme:

[0006] A physicochemical thermal washing process for oily sludge includes the following steps:

[0007] S1. Coarse washing: The oily sludge after being processed by the crusher enters the coarse washing section, where the oily sludge is initially separated. The separated oil is discharged into the waste oil recovery tank for storage, and the remaining oily sludge is discharged into the fine washing section.

[0008] S2. Fine washing: The oily sludge that has undergone preliminary separation is washed and separated again in the fine washing section. The separated oil is discharged into the waste oil recovery tank for storage, and the remaining oily sludge is discharged into the first rinsing section.

[0009] S3, First rinsing section: Add clean water to the rinsing section to rinse the oily sludge after the secondary washing and separation, so that the oil and sludge are further separated. The separated oil is discharged into the waste oil recovery tank for storage, and the remaining oily sludge is discharged into the second rinsing section.

[0010] S4. Second rinsing section: The oily sludge separated in the first rinsing section is rinsed a second time to completely separate the oil and sludge. The separated oil is discharged into the oil and sludge recovery tank for storage, and the separated water and sludge are discharged into the settling section.

[0011] S5. Sedimentation: Water and mud are statically separated in the sedimentation section, with suspended solids settling down, and the separated water and mud are discharged into the filter press.

[0012] S6. Filtration: The water and mud discharged into the settling section are separated into solids and liquids by a plate and frame filter press. The separated water is discharged into the wastewater recycling tank, and the separated mud is discharged into the sludge recycling tank.

[0013] S7. Resource recycling: The water from the wastewater recycling pond after separation is recycled as water for preparing pharmaceutical agents, and the sludge from the sludge recycling pond after separation is used for landscaping or road repair.

[0014] Furthermore, when separating the oily sludge in the coarse washing section S1 and the fine washing section S2, the process involves chemical soaking, mechanical stirring, and air stirring.

[0015] Furthermore, the stirring time for both the coarse washing section and the fine washing section is 40-60 minutes, the temperature is 70-80℃, and the reagent concentration is 5-7%.

[0016] Furthermore, the reagent is pumped from the reagent recovery tank into the coarse washing section and the fine washing section. The inlet of the reagent recovery tank is connected to the wastewater recovery tank. The water separated by the plate and frame filter press enters the reagent recovery tank as water for preparing the reagent.

[0017] Furthermore, during mechanical mixing, a horizontal double-blade agitator is used to mix the oily sludge, while during air mixing, an air compressor is used to pump compressed air into the coarse washing section and the fine washing section to perform air shocks on the fine local parts of the material.

[0018] Furthermore, the crusher in step S1 is a shear crusher.

[0019] Furthermore, in step S4, after adding flocculant to the second rinsing section, the mixture is stirred and run for 10-20 minutes.

[0020] Furthermore, in step S6, the sludge after pressure filtration has an oil content of less than 3%, and is then air-dried or oven-dried.

[0021] Furthermore, the sludge separated from the coarse washing section, fine washing section, first rinsing section, and second rinsing section enters the sludge recovery tank through a shared pipeline.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The process involves coarse washing, fine washing, first rinsing, second rinsing, settling, and a plate and frame filter press to achieve the three-phase separation of oil and cement, ensuring that the oil content meets the standards. The treated sludge has an oil content of less than 3%, and after being air-dried or oven-dried, it can be used for landscaping or road construction. The water separated by the plate and frame filter press enters the chemical recovery tank as water for preparing chemical agents, thus achieving water recycling. Attached Figure Description

[0024] Figure 1 This is a flowchart of the overall process of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Combination Figure 1 This invention provides a physicochemical thermal washing process for oily sludge, mainly including the following steps: coarse washing, fine washing, primary rinsing, secondary rinsing, settling, and pressure filtration.

[0027] S1. Coarse washing: The oily sludge after being processed by the crusher enters the coarse washing section, where the oily sludge is initially separated. The separated oil is discharged into the waste oil recovery tank for storage, and the remaining oily sludge is discharged into the fine washing section.

[0028] S2. Fine washing: The oily sludge that has undergone preliminary separation is washed and separated again in the fine washing section. The separated oil is discharged into the waste oil recovery tank for storage, and the remaining oily sludge is discharged into the first rinsing section.

[0029] S3, First rinsing section: Add clean water to the rinsing section to rinse the oily sludge after the secondary washing and separation, so that the oil and sludge are further separated. The separated oil is discharged into the waste oil recovery tank for storage, and the remaining oily sludge is discharged into the second rinsing section.

[0030] S4. Second rinsing section: The oily sludge separated in the first rinsing section is rinsed a second time to completely separate the oil and sludge. The separated oil is discharged into the oil and sludge recovery tank for storage, and the separated water and sludge are discharged into the settling section.

[0031] S5. Sedimentation: Water and mud are statically separated in the sedimentation section, with suspended solids settling down, and the separated water and mud are discharged into the filter press.

[0032] S6. Filtration: The water and mud discharged into the settling section are separated into solids and liquids by a plate and frame filter press. The separated water is discharged into the wastewater recycling tank, and the separated mud is discharged into the sludge recycling tank.

[0033] S7. Resource recycling: The water from the wastewater recycling pond after separation is recycled as water for preparing pharmaceutical agents, and the sludge from the sludge recycling pond after separation is used for landscaping or road repair.

[0034] The process of this invention can be used for the treatment of oily sludge in the fields of petroleum and petrochemical, steel, machining, ship oil tank sludge, and dock oil storage tank area. By adopting the above steps, the oily sludge achieves the three-phase separation of oil, water and sludge through different process stages, realizes the treatment of oil content to meet the standards, and realizes the resource utilization of oil, water and sludge.

[0035] Preferably, in this embodiment, the rough washing, fine washing, first rinsing section, and second rinsing section are all processed using two sets of parallel skid-mounted equipment, thereby increasing work efficiency.

[0036] Preferably, in the coarse washing section (S1) and fine washing section (S2), the oily sludge is separated by chemical soaking, mechanical stirring, and air stirring. Using mechanical stirring and air stirring allows for simultaneous agitation of the materials within the bulk material, thereby achieving better separation results and improving separation efficiency.

[0037] In this embodiment, the stirring time for both the coarse washing section and the fine washing section is 40-60 minutes, the temperature is 70-80℃, and the reagent concentration is 5-7%. The relatively low temperature of 70-80℃ protects the main nutrients in the sludge, making it suitable for landscaping and roadbed construction.

[0038] Preferably, the reagent consists of a main agent and an auxiliary agent. The concentration of the main agent is 5%, and the raw material mass percentage of the main agent is as follows: sodium metasilicate pentahydrate 0.5-4.5%, potassium hydroxide 0.01-40.03%, glycerol 1-43%, organic amine ester 5-48%, sodium heavy carbonate 1-43%, fatty alcohol polyether 0.5-4%, nonionic surfactant 1-43%; the remainder is water. The concentration of the auxiliary agent is 2%, and the raw material mass percentage of the auxiliary agent is as follows: potassium hydroxide 0.1-40.4%, low-foaming surfactant 1-43%, heavy oil soaking and degreasing surfactant 1-42.5%, ethylene glycol butyl ether 2-45%, degreasing and dewaxing surfactant 1-43%; the remainder is water.

[0039] In this embodiment, the reagent is pumped from the reagent recovery tank into the coarse washing section and the fine washing section. The inlet of the reagent recovery tank is connected to the wastewater recovery tank. The water separated by the plate and frame filter press enters the reagent recovery tank as water for preparing the reagent.

[0040] In this embodiment, a horizontal double-blade agitator is used to agitate the oily sludge during mechanical stirring. The horizontal double-blade agitator is equipped with spiral blades rotating in opposite directions, which can generate relative rotation and improve the stirring efficiency of the material. During air stirring, an air compressor is used to pump compressed air into the coarse washing section and the fine washing section to perform air shock explosion on the fine local parts of the material. The air compressor pump pumps tiny bubbles into the material through the air holes on the air pipe and explodes them at any time, thereby forming a fine local high-pressure bombardment of the material, which causes the oil and water on the surface and in the gaps of the mud and sand to be quickly stripped off, thereby achieving the initial separation of oil, mud and water and improving the separation effect.

[0041] In this embodiment, the crusher in step S1 is a shear crusher.

[0042] In this embodiment, after adding flocculant in the second rinsing section of step S4, the mixture is stirred and run for 10-20 minutes.

[0043] In this embodiment, the sludge after pressure filtration in step S6 has an oil content of less than 3%, and is then air-dried or oven-dried for use in landscaping or road repair.

[0044] In this embodiment, the sludge separated from the coarse washing section, fine washing section, first rinsing section, and second rinsing section enters the sludge recovery tank through a common pipeline.

[0045] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A physicochemical thermal washing process for oily sludge, characterized in that, Includes the following steps: S1. Coarse washing: The oily sludge after being processed by the crusher enters the coarse washing section, where the oily sludge is initially separated. The separated oil is discharged into the waste oil recovery tank for storage, and the remaining oily sludge is discharged into the fine washing section. S2. Fine washing: The oily sludge that has undergone preliminary separation is washed and separated again in the fine washing section. The separated oil is discharged into the waste oil recovery tank for storage, and the remaining oily sludge is discharged into the first rinsing section. S3, First rinsing section: Add clean water to the rinsing section to rinse the oily sludge after the secondary washing and separation, so that the oil and sludge are further separated. The separated oil is discharged into the waste oil recovery tank for storage, and the remaining oily sludge is discharged into the second rinsing section. S4. Second rinsing section: The oily sludge separated in the first rinsing section is rinsed a second time to completely separate the oil and sludge. The separated oil is discharged into the oil and sludge recovery tank for storage, and the separated water and sludge are discharged into the settling section. S5. Sedimentation: Water and mud are statically separated in the sedimentation section, with suspended solids settling down, and the separated water and mud are discharged into the filter press. S6. Filtration: The water and mud discharged into the settling section are separated into solids and liquids by a plate and frame filter press. The separated water is discharged into the wastewater recycling tank and the separated mud is discharged into the sludge recycling tank. S7. Resource recycling: The water from the wastewater recycling pond after separation is recycled as water for preparing pharmaceutical agents, and the sludge from the sludge recycling pond after separation is used for landscaping or road repair. When separating oily sludge in the coarse washing section S1 and the fine washing section S2, chemical soaking, mechanical stirring and air stirring are used for treatment. The reagent consists of a main agent and auxiliary agents. The concentration of the main agent is 5%, and the raw material mass percentage of the main agent is as follows: sodium metasilicate pentahydrate 0.5-4.5%, potassium hydroxide 0.01-40.03%, glycerol 1-43%, organic amine ester 5-48%, sodium heavy carbonate 1-43%, fatty alcohol polyether 0.5-4%, nonionic surfactant 1-43%; the remainder is water. The concentration of the auxiliary agents is 2%, and the raw material mass percentage of the auxiliary agents is as follows: potassium hydroxide 0.1-40.4%, low-foaming surfactant 1-43%, heavy oil soaking and degreasing surfactant 1-42.5%, ethylene glycol butyl ether 2-45%, degreasing and dewaxing surfactant 1-43%. The rest is water; The stirring time for both the coarse washing section and the fine washing section is 40-60 minutes, and the temperature is 70-80℃. The reagent is pumped from the reagent recovery tank into the coarse washing section and the fine washing section. The inlet of the reagent recovery tank is connected to the wastewater recovery tank. The water separated by the plate and frame filter press enters the reagent recovery tank as water for preparing the reagent. During mechanical mixing, a horizontal double-blade agitator is used to mix the oily sludge. During air mixing, an air compressor is used to pump compressed air into the coarse washing section and the fine washing section to perform air shocks on the fine parts of the material.

2. The physicochemical thermal washing process for oily sludge as described in claim 1, characterized in that, The crusher used in step S1 is a shear crusher.

3. The physicochemical thermal washing process for oily sludge as described in claim 1, characterized in that, After adding flocculant in the second rinsing section of step S4, stir and run for 10-20 minutes.

4. The physicochemical thermal washing process for oily sludge as described in claim 1, characterized in that, In step S6, the sludge after pressure filtration has an oil content of less than 3‰, and then it is air-dried or oven-dried.

5. The physicochemical thermal washing process for oily sludge as described in claim 1, characterized in that, The sludge separated from the coarse washing section, fine washing section, first rinsing section, and second rinsing section enters the sludge recovery tank through a shared pipeline.

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