Steel rolling oil sludge iron powder-grease collaborative recovery treatment method and system

Abstract

The invention relates to a steel rolling oil sludge iron powder-grease synergistic recovery treatment system which comprises a pretreatment unit, a gradient magnetic separation unit, a solid-liquid separation unit, a low-temperature distillation unit, an iron powder recovery unit, a grease purification unit and a tail water treatment unit. The demulsified oil sludge enters the magnetic separation unit, the magnetic separation unit performs magnetic attraction treatment on iron powder in the oil sludge, the oil sludge enters the solid-liquid separation unit after the iron powder is removed, the removed iron powder enters the iron powder recovery unit to be treated, and a liquid phase separated by the solid-liquid separation unit is distilled by the low-temperature distillation unit and then enters the grease purification unit to purify grease; and solid-phase residues separated out by the solid-liquid separation unit are transported outwards for treatment, wastewater separated out by the solid-liquid separation unit enters the tail water treatment unit for treatment, and in a word, the system has the advantages of being high in separation efficiency, high in iron powder recovery purity, low in energy consumption, remarkably improved in grease recovery rate, small in environmental pollution and high in automation degree.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of industrial hazardous waste treatment, and particularly relates to a rolling oil sludge and iron powder-oil grease collaborative recovery treatment system. BACKGROUND

[0002] Rolling oil sludge is a typical iron-containing solid waste generated in the hot rolling process of the steel industry. A large amount of rolling oil sludge is generated during the rolling production process. When the billet is rolled at high temperature, the lubricating oil and grease used by the roller and the roller equipment are mixed with the iron oxide scale falling off the surface of the billet, and are washed into the hot rolling turbid water treatment system by the oil-containing cooling water, and finally form oil-containing sludge in the sedimentation treatment unit. From the analysis of the composition of matter, the oil in the rolling oil sludge is complex and diverse, about 55% of which is alkane and alkene, and 22% of which is carboxylic acid, ketone and aromatic hydrocarbon compound 2, which is very difficult to handle. Moreover, this special mixture has the characteristics of strong adhesion and easy corruption and odor. Natural piling not only produces a pungent odor, but also causes oil leakage to pollute the soil and water. Moreover, the oil sludge contains high-value iron resources (the total iron content of dry basis can reach 67% to 72%), which is difficult to collect due to the oil problem and is difficult to be directly recycled and utilized, which easily causes resource waste. However, the steel industry in China produces about 1.2 million tons of hot rolling oil sludge every year, and the production is very large. With the continuous high operation of the steel output, the production is still increasing. The treatment and resource utilization of the rolling oil sludge become an environmental protection and production problem to be solved by the steel enterprises. The recycling and treatment of the rolling oil sludge have great economic and social benefits.

[0003] At present, there are devices for separating iron powder and oil grease from rolling oil sludge by combining various devices. However, these devices do not form an automatic system, which not only has high cost, but also is not convenient to use. Moreover, there are other problems in the whole treatment process. First, the separation efficiency is low. Due to the characteristics of the oil sludge, the oil sludge is highly emulsified during the processing process, and the particle size of the iron powder in the oil sludge is very small. The traditional centrifugation or magnetic separation is difficult to completely separate. Second, the secondary pollution problem exists. The oil sludge is easy to produce volatile organic compounds during solvent extraction or high-temperature cracking. These organic compounds are difficult to handle and are very easy to cause pollution. Third, the energy consumption is high. The whole system involves multiple rotary kilns and distillation columns, which not only has high energy consumption, but also easily damages the quality of the oil grease. Finally, the process is complex. The oil grease treatment process needs multiple washing, centrifugation and distillation, which greatly increases the cost.

[0004] Therefore, a rolling oil sludge and iron powder-oil grease collaborative recovery treatment system is urgently needed to solve the problems of low separation efficiency, easy secondary pollution, complex process, high energy consumption and low iron powder extraction purity. SUMMARY

[0005] In view of the above, the present application provides a rolling oil sludge iron powder-oil grease synergistic recovery treatment system, which belongs to the field of industrial hazardous waste treatment and can solve the technical problems of low oil grease recovery efficiency, no high-purity extraction of iron powder, complex process, low automation degree and environmental pollution caused by production process.

[0006] In order to achieve the above technical purpose, the specific technical scheme adopted by the present application is as follows: The rolling oil sludge iron powder-oil grease synergistic recovery treatment system comprises a pretreatment unit, a gradient magnetic separation unit, a solid-liquid separation unit, a low-temperature distillation unit, an iron powder recovery unit, an oil grease purification unit and a tail water treatment unit. The pretreatment unit adds a compounded surfactant to perform demulsification treatment on the oil sludge. The demulsified oil sludge enters the magnetic separation unit. The magnetic separation unit performs magnetic attraction treatment on the iron powder in the oil sludge. After the iron powder is removed, it enters the solid-liquid separation unit. The removed iron powder enters the iron powder recovery unit for treatment. The liquid phase separated by the solid-liquid separation unit is distilled by the low-temperature distillation unit and then enters the oil grease purification unit to purify the oil grease. The solid phase residue separated by the solid-liquid separation unit is transported for treatment. The wastewater separated by the solid-liquid separation unit enters the tail water treatment unit for treatment. The low-temperature distillation unit is connected with a steel plant waste heat pipeline to provide the heat required for low-temperature distillation.

[0007] Further, the oil sludge and the anti-sticking ball surfactant are precisely mixed in a ratio of 2:1 in the pretreatment unit. The oil sludge and the anti-sticking ball surfactant are ball milled at 0.8kW and 400r / h for 12h to destroy the water-in-oil emulsion structure by mechanical shearing. The dissociation degree of the iron powder is increased to 90% in the pretreatment unit.

[0008] Further, the anti-sticking ball surfactant is stored in an anti-sticking agent storage tank. The anti-sticking ball surfactant is compounded by sodium ethylenediaminetetraacetate and sodium dodecyl sulfonate.

[0009] Further, the gradient magnetic separation unit comprises a high-gradient magnetic separator with a magnetic field strength not less than 1.2T, a nano-magnetic bead dosing system containing Fe3O4 suspension and a wet magnetic separation tank. The high-gradient magnetic separator separates iron powder larger than 1μm. The nano-magnetic bead reactor in the nano-magnetic bead dosing system separates iron powder smaller than 1μm.

[0010] Further, the solid-liquid separation unit comprises a plate-and-frame filter press and a horizontal screw centrifuge. The plate-and-frame filter press is used to remove large-particle solids. The horizontal screw centrifuge is used to centrifuge the remaining solid-liquid two-phase at a high speed of 15000r / min for 5min.

[0011] Further, the low-temperature distillation unit comprises a multi-effect distillation column, a condensation recovery system and a waste heat exchanger, the multi-effect distillation column separates purified rolling grease from the oil slurry and recovers the extractant, avoiding oil quality deterioration caused by high temperature.

[0012] Further, the extractant is recovered by using propylene glycol block polyether extractant, and the same batch of propylene glycol block polyether extractant is recycled for 5 times.

[0013] Further, the low-temperature distillation unit utilizes the heat in the 140-150℃ waste water in the steel plant waste heat pipeline through the multi-effect distillation column and the waste heat exchanger.

[0014] Further, the tail water treatment unit can perform reuse water treatment and heavy metal precipitation treatment, and the tail water treatment unit comprises an automatic dosing system, a flocculation reaction tank, an inclined plate sedimentation tank and a water quality monitor, the waste water separated by the solid-liquid separation unit enters the flocculation reaction tank, polymeric ferric phosphate sulfate and sodium dihydrogen phosphate are added by the automatic dosing system for reaction, the mass ratio of polymeric ferric phosphate sulfate and sodium dihydrogen phosphate is 2:1, and after reaction, clear water and heavy metal sludge are separated in the inclined plate sedimentation tank, achieving zero waste water discharge.

[0015] By adopting the technical scheme, the application can also bring the following beneficial effects: 1. The application discloses a rolling steel oil slurry iron powder-oil grease collaborative recovery treatment system, which reduces the viscosity of the oil slurry by compounding surfactants, improves the iron powder recovery rate by gradient magnetic separation, solves the problem of micron particle separation, realizes oil grease low-temperature distillation by using steel plant waste heat in the whole treatment process, saves energy by more than 30% and avoids oil quality damage, is very friendly to the environment, the purity of the treated iron powder is more than 99%, the oil grease recovery rate is more than 95%, and waste water is recycled by 100%, without causing secondary pollution, and has the advantages of high separation efficiency, high iron powder recovery purity, full use of steel plant waste heat to reduce energy consumption and no secondary pollution to the environment.

[0016] 2. The application discloses a rolling steel oil slurry iron powder-oil grease collaborative recovery treatment system, which realizes full-process automation by controlling parameters (such as temperature, speed and pressure) of each link by a PLC, improves the treatment efficiency of oil slurry demulsification in the pretreatment unit by a ball mill and an automatic anti-sticking agent adding system, improves the solid-liquid separation effect in the separation unit by a high-gradient magnetic separator, a plate-and-frame filter press and a horizontal screw centrifuge, reduces the energy consumption in the distillation module by a waste heat utilization type multi-effect distillation column and a condensation recovery system, and reduces the cost, and has the advantages of good solid-liquid separation effect, energy saving, cost reduction, high oil grease purification efficiency and high automation degree. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1The application relates to a module connection diagram of a rolling oil sludge iron powder-oil grease cooperative recovery treatment system. DETAILED DESCRIPTION

[0018] Other advantages and benefits of the present application will become apparent to those skilled in the art, upon consideration of the following detailed description of embodiments of the application. It is to be understood that even though a number of embodiments of the application are described herein, they are presented by way of example only and are not limiting as to the scope of the application. The application can be implemented or applied in other ways, and modifications can be made without departing from the spirit of the application. It is intended that the present application encompass all such modifications and variations as fall within the scope of the appended claims. It is to be understood that the following examples and features in the examples are combinable, where possible, without conflict.

[0019] It is to be understood that the following description of aspects is merely illustrative of the aspects within the scope of the appended claims. It is to be understood that aspects described herein can be implemented in a wide variety of forms and that any particular structure and / or functions described herein are merely illustrative. Based on the present disclosure, a person skilled in the art can know other ways to implement one aspect described herein with any other aspect or aspects. For example, an apparatus can be implemented using any number of the aspects described herein. In addition, an apparatus can be implemented with other structures and / or functionalities beyond those described herein.

[0020] It is also to be understood that the drawings provided herein are merely schematic and that actual implementations of the application can differ in terms of layout, number of components, shapes and sizes of components, etc. from those shown in the drawings.

[0021] In addition, in the following description, specific details are given to provide a thorough understanding of the examples. However, one skilled in the relevant art will understand that the aspects described can be practiced without these specific details.

[0022] As Figure 1As shown, in one embodiment of the present application, a rolling oil sludge iron powder-oil grease synergistic recovery treatment system is mentioned, which includes a pretreatment unit, a gradient magnetic separation unit, an esterification reaction unit, a solid-liquid separation unit, a low-temperature distillation unit, an iron powder recovery unit, an oil purification unit and a tail water treatment unit. 100 kg of rolling oil sludge is added to the pretreatment unit, the oil sludge is subjected to demulsification treatment in the pretreatment unit, the demulsified oil sludge is subjected to flowability and iron powder dissociation degree detection, and then enters the magnetic separation unit. The magnetic separation unit performs magnetic attraction treatment on the iron powder in the oil sludge, and the iron powder after removal enters the solid-liquid separation unit. The removed iron powder enters the iron powder recovery unit for treatment, the recovered iron powder is subjected to weighing treatment, and the Fe content is calculated. The liquid phase separated by the solid-liquid separation unit is distilled by the low-temperature distillation unit, and then enters the esterification reaction unit to purify oil. The solid phase residue separated by the solid-liquid separation unit is transported for treatment, and the oil content is calculated before treatment. The waste water separated by the solid-liquid separation unit enters the tail water treatment unit for treatment. The oil purified in the esterification reaction unit is recovered using an extractant, the extractant is propylene glycol block polyether extractant, and the same batch of propylene glycol block polyether extractant is recycled for 5 times. Finally, high-purity rolling oil is obtained, and the rolling oil is weighed.

[0023] The oil sludge and the anti-sticking ball surfactant in the pretreatment unit are precisely mixed in a ratio of 2:1, the oil sludge and the anti-sticking ball surfactant are ball milled under the condition of 0.8 kW and 400 r / h for 12 h, the water-in-oil emulsion structure is destroyed by mechanical shearing, the flowability of the oil sludge subjected to demulsification treatment is improved by 80%, and the dissociation degree of the iron powder is improved to 90% in the pretreatment unit. The anti-sticking ball surfactant is stored in an anti-sticking agent storage tank, and the anti-sticking ball surfactant is compounded by sodium ethylenediaminetetraacetate and sodium dodecyl sulfonate.

[0024] The gradient magnetic separation unit includes a high-gradient magnetic separator with a magnetic field strength not less than 1.2 T, a nano-magnetic bead dosing system containing Fe3O4 suspension, and a wet magnetic separation tank. The high-gradient magnetic separator separates iron powder greater than 1 μm, the nano-magnetic bead reactor in the nano-magnetic bead dosing system separates iron powder less than 1 μm, and the recovered iron powder is 75 kg, and the Fe content is greater than 99%.

[0025] The solid-liquid separation unit includes a plate and frame filter press and a horizontal screw centrifuge. The plate and frame filter press is used to remove large particle solids, and the horizontal screw centrifuge is used to centrifuge the remaining solid-liquid two-phase at a speed of 15000 r / min for 5 min. The oil content of the solid phase residue after centrifugation is less than 2% after calculation.

[0026] The low-temperature distillation unit comprises a multi-effect distillation column, a condensation recovery system and a waste heat exchanger, the multi-effect distillation column separates the purified rolling grease from the oil and fat mixture and recovers the extractant, avoiding the deterioration of the oil quality caused by high temperature. The low-temperature distillation unit utilizes the heat in the 140-150 DEG C waste water in the steel plant waste heat pipeline through the multi-effect distillation column and the waste heat exchanger. The tail water treatment unit can treat the recycled water and precipitate the heavy metals, the tail water treatment unit comprises an automatic dosing system, a flocculation reaction tank, an inclined plate sedimentation tank and a water quality monitor, the waste water separated by the solid-liquid separation unit enters the flocculation reaction tank, polymeric ferric sulfate and sodium dihydrogen phosphate are added by the automatic dosing system for reaction, the mass ratio of polymeric ferric sulfate and sodium dihydrogen phosphate is 2:1, after reaction, the water is separated from the heavy metal sludge in the inclined plate sedimentation tank, achieving zero waste water discharge.

[0027] Finally, 20 kg of rolling oil is obtained through oil purification, the oil recovery rate is more than 95%, which is very friendly to the environment, the purity of the treated iron powder is more than 99%, which significantly improves the iron powder recovery rate, the oil slurry viscosity is reduced by compounding surfactants during the whole process, and the oil is distilled at low temperature by using the waste heat of the steel plant, which saves more than 30% of energy and avoids oil damage, the waste water is also recycled by 100%, without causing secondary pollution, in summary, the present application has the advantages of high separation efficiency, high iron powder recovery purity, low energy consumption, significantly improved oil recovery rate, small environmental pollution and high automation degree.

[0028] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A steel rolling sludge, iron powder, and grease co-recovery and treatment system, characterized in that: The application relates to a waste oil sludge treatment device.

2. A system for the synergic recovery of iron powder and oil from a rolling mill sludge according to claim 1, characterized in that: The complex surfactant is used in the pretreatment unit, and the oil sludge is subjected to demulsification treatment through the complex surfactant; the demulsified oil sludge enters a magnetic separation unit; the magnetic separation unit is used for magnetically attracting and removing iron powder in the oil sludge; the removed iron powder enters an iron powder recovery unit; liquid phase separated by a solid-liquid separation unit is subjected to distillation through a low-temperature distillation unit; the distillation liquid enters an oil purification unit to purify oil; solid phase separated by the solid-liquid separation unit is transported out; waste water separated by the solid-liquid separation unit enters a tail water treatment unit; and the low-temperature distillation unit is connected with a steel mill waste heat pipeline to provide heat required by low-temperature distillation.

3. A system for the synergic recovery of iron powder and oil from a rolling mill sludge according to claim 2, characterized in that: The complex surfactant is a anti-sticking ball surfactant, and the oil sludge and the anti-sticking ball surfactant are accurately mixed at a ratio of 2:1; the oil sludge and the anti-sticking ball surfactant are ball milled at 0.8 kW and 400 r / h for 12 h to destroy water-in-oil emulsion structure through mechanical shearing; and the dissociation degree of the iron powder is increased to 90% in the pretreatment unit.

4. A system for the synergic recovery of iron powder and oil from a rolling mill sludge according to claim 3, characterized in that: The anti-sticking ball surfactant is stored in an anti-sticking agent storage tank and is prepared by compounding sodium ethylenediaminetetraacetate and sodium dodecyl sulfonate.

5. A system for the synergistic recovery of iron powder and oil from a rolling mill sludge according to claim 4, characterized in that: The gradient magnetic separation unit comprises a high-gradient magnetic separator with a magnetic field strength of not less than 1.2 T, a nano magnetic bead adding system containing Fe3O4 suspension and a wet magnetic separation tank; the high-gradient magnetic separator is used for separating iron powder with a size larger than 1 mu m; and the nano magnetic bead reactor in the nano magnetic bead adding system is used for separating iron powder with a size smaller than 1 mu m.

6. A system for the synergistic recovery of iron powder and oil from a rolling mill sludge as claimed in claim 5, wherein: The solid-liquid separation unit comprises a plate-and-frame filter press and a horizontal screw centrifuge; the plate-and-frame filter press is used for removing large-particle solid; and the horizontal screw centrifuge is used for high-speed centrifuging remaining solid-liquid two-phase under the condition of 15000 r / min and 5 min.

7. A system for the synergistic recovery of iron powder and oil from a rolling mill sludge according to claim 6, characterized in that: The low-temperature distillation unit comprises a multi-effect distillation tower, a condensation recovery system and a waste heat exchanger; the multi-effect distillation tower is used for separating purified rolling oil from oil mixture and recovering an extractant to avoid oil quality deterioration caused by high temperature.

8. A system for the synergistic recovery of iron powder and oil from a rolling mill sludge according to claim 7, characterized in that: The extractant is a propylene glycol block polyether extractant, and the same batch of propylene glycol block polyether extractant is recycled for 5 times.

9. A system for the synergistic recovery of iron powder and oil from a rolling mill sludge according to claim 8, characterized in that: The low-temperature distillation unit utilizes waste heat in the steel mill waste heat pipeline through the multi-effect distillation tower and the waste heat exchanger.

10. A synergic recovery system of rolling oil sludge and iron powder-fatty grease as claimed in claim 98, characterized in that: The tail water treatment unit can be used for treating recycled water and precipitating heavy metals; the tail water treatment unit comprises an automatic dosing system, a flocculation reaction tank, an inclined plate sedimentation tank and a water quality monitor; the waste water separated by the solid-liquid separation unit enters the flocculation reaction tank; and polymeric ferric phosphate sulfate and sodium dihydrogen phosphate are added into the flocculation reaction tank through the automatic dosing system to react. The mass ratio of the polymeric ferric phosphate sulfate and the sodium dihydrogen phosphate in the tail water treatment unit is 2:1; the waste water in the flocculation reaction tank enters the inclined plate sedimentation tank to separate clean water and heavy metal sludge, so that zero waste water discharge is realized.

Images