A method for treating sludge

Abstract

This application relates to the technical field of petrochemical industry, and specifically discloses a method for treating oil sludge. The method for treating oil sludge disclosed in this application specifically includes the following steps: treating the oil sludge with basic metallized pellets, carbon-based biomass and polyacrylamide, wherein the weight ratio of the basic metallized pellets, the carbon-based biomass, the polyacrylamide to the oil sludge is (20-30):(10-20):(2-5):100; the basic metallized pellets are composed of metallized pellets and alkali metal hydroxides with a weight ratio of 100:(5-20). By using the method for treating oil sludge provided in this application, the separation effect of the oil, water and solid phases in the oil sludge can be effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of petrochemical industry, and specifically relates to a method for treating oily sludge. Background Art

[0002] A large amount of oily sludge is generated during the processes of crude oil exploitation, refining, storage, etc., which is usually simply referred to as oily sludge; if the oily sludge is not treated and directly discharged, it will cause pollution to the surrounding soil, water body and air. However, the characteristics of oily sludge are that it contains a variety of toxic and harmful substances, has a high water content, small solid particles, serious oil-water-solid emulsification, and is difficult to dehydrate. Therefore, the problem of oily sludge treatment has always been a difficult problem for petrochemical enterprises.

[0003] The ultimate goal of oily sludge treatment is based on the principles of reduction, resource utilization and harmlessness. At present, the main treatment methods for oily sludge are chemical hot washing method, high-temperature incineration method and pyrolysis method. However, these three treatment methods not only have high energy consumption and long treatment time, which increase the cost; in addition, the treatment effects of the above methods are poor, such as incomplete separation of oil, water and solid phases, high COD content in water, and low oil recovery rate, and they cannot fundamentally solve the pollution of oily sludge. Summary of the Invention

[0004] In order to treat oily sludge with low energy consumption and low cost, and at the same time improve the separation effect of oil, water and solid phases in oily sludge, the present application provides a method for treating oily sludge.

[0005] A method for treating oily sludge adopts the following technical scheme:

[0006] A method for treating oily sludge specifically includes the following steps:

[0007] Treat the oily sludge with basic metallized pellets, carbon-based biomass and polyacrylamide,

[0008] wherein, the weight ratio of the basic metallized pellets, the carbon-based biomass, the polyacrylamide to the oily sludge is (20 - 30):(10 - 20):(2 - 5):100;

[0009] The basic metallized pellets are composed of metallized pellets and alkali metal hydroxides with a weight ratio of 100:(10 - 20).

[0010] This application uses carbon-based biomass, alkaline metalized pellets, and polyacrylamide to treat oily sludge. After centrifugally separating the solid and liquid phases and separating oil and water, the water phase, oil phase, and solid phase in the oily sludge are well separated. The water-phase material after treating the oily sludge meets the requirements of the sewage treatment plant for the oil content and COD content in the water; the recovery rate of the oil-phase material is relatively high, and the water content in the oil-phase material is relatively low, and this oil-phase material can enter the recycling system for recovery and utilization; moreover, the oil content and water content of the solid-phase material are relatively low. That is, using the treatment method for oily sludge provided by this application significantly improves the treatment effect of oily sludge.

[0011] The alkaline metalized pellets used in this application have the characteristics of being porous and easy to adsorb. After being mixed with oily sludge, they are easy to adsorb the fine particles in the oily sludge; the alkaline metalized pellets mixed with oily sludge are easy to generate divalent or trivalent iron ions, and then attract the slightly negatively charged particles in the oily sludge by opposite-sex attraction to form relatively stable flocs to remove the slightly negatively charged particles. In addition, the applicant found that the addition of carbon-based biomass can enhance the treatment effect of alkaline metalized pellets because an infinite number of fine primary batteries can be formed between the alkaline metalized pellets and carbon-based biomass due to the potential difference between the iron-carbon particles, thereby forming a micro-electrolysis reaction, which further strengthens the flocculation effect of divalent or trivalent iron ions.

[0012] The polyacrylamide used in this application is a linear organic polymer with abundant positive groups of amide groups. It can be dispersed in the oily sludge liquid and adsorb the suspended particles in the oily sludge liquid, playing a role of linking and bridging between the suspended particles to make the fine particles form relatively large flocs, thereby improving the separation speed and separation effect of the oil, water, and solid phases in the oily sludge.

[0013] In addition, since the oil, water, and solid phases in the oily sludge are mixed together, the effect of using only alkaline metalized pellets or only polyacrylamide is relatively poor. The applicant found that alkaline metalized pellets, carbon-based biomass, and polyacrylamide can cooperate synergistically to break the emulsification of oil and water, destroy the structure of the organic polymer microparticles in the oily sludge, and disperse the agglomerated oily particles. At the same time, the iron ions in the alkaline metalized pellets and polyacrylamide play a flocculation role, causing the oil phase to accumulate, and the accumulation of the oil phase promotes the demulsification effect. Therefore, in the treatment method of oily sludge, the demulsification effect and the flocculation effect promote each other, which is beneficial to improving the separation of oil and water and the sedimentation of the solid phase, thus promoting the separation effect of the oil, water, and solid phases.

[0014] The performance indexes of the oily sludge treated by this application are water content > 95wt% and oil content = 3 - 5wt%.

[0015] In a specific embodiment, the weight ratio of the alkaline metallized pellets, the carbon-based biomass, the polyacrylamide, and the oily sludge can be 20:10:2:100, 25:10:2:100, 30:10:2:100, 20:15:2:100, 25:15:2:100, 30:15:2:100, 20:20:2:100, 25:20:2:100, 30:20:2:100, 20:10:4:100, 25:4:2:100, 30:10:4:100, 20:10:5:100, 25:5:2:100, 30:10:5:100,

[0016] In some specific embodiments, the weight ratio of the alkaline metallized pellets, the carbon-based biomass, the polyacrylamide, and the oily sludge can also be (20 - 25):(10 - 15):(2 - 4):100, (25 - 30):(15 - 20):(4 - 5):100.

[0017] Through experimental analysis, it can be known that during the treatment of oily sludge, when the input amounts of alkaline metallized pellets, carbon-based biomass, or polyacrylamide are too small, the treatment effect of the oily sludge is poor.

[0018] When the input amount of alkaline metallized pellets or carbon-based biomass is too large, excessive divalent or trivalent iron ions are generated; and divalent iron ions have strong reducibility and are prone to oxidation reactions to generate trivalent iron ions and O2 - free radicals, O2 - Free radicals have high activity and then react with polyacrylamide, causing the molecular chain of polyacrylamide to break; during the breaking process of the molecular chain of polyacrylamide, new free radicals are generated to react with trivalent iron ions, regenerating divalent iron ions, further exacerbating the degradation of polyacrylamide, causing the viscosity of polyacrylamide to decrease sharply, thereby reducing the flocculation ability of the treatment system.

[0019] In addition, when the dosage of polyacrylamide is too large, the micro-electrolysis reaction between metallized pellets and carbon-based biomass is inhibited, reducing the generation amount of iron ions, thereby reducing the separation effect of the oil, water, and solid phases in the oily sludge.

[0020] Therefore, the weight ratio of the alkaline metallized pellets, carbon-based biomass, polyacrylamide, and oily sludge in this application is controlled within the above range.

[0021] Preferably, in the treatment method of the oily sludge, the addition order of each raw material is:

[0022] First, add the polyacrylamide to the oily sludge; then add the mixture of the alkaline metallized pellets and the carbon-based biomass.

[0023] Through experimental analysis, it is known that when alkaline metallized pellets, carbon-based biomass and non-ionic polyacrylamide are put into oily sludge together, the treatment effect of the oily sludge is poor. This is because the alkaline metallized pellets and wood chips are not fully mixed, weakening the effect of micro-electrolysis. At the same time, the treatment method of putting the raw materials into the oily sludge together easily causes the iron ions and the functional groups of polyacrylamide to attract each other first and cross-link, resulting in the breakage of the molecular chain of polyacrylamide and the inability to extend, causing the viscosity of polyacrylamide to drop sharply, thereby reducing the flocculation ability of iron ions and polyacrylamide.

[0024] In this application, it is selected to first fully mix the oily sludge with non-ionic polyacrylamide to break the emulsification of oil and water in advance and destroy the structure of organic polymer microparticles in the oily sludge; then add a mixture of alkaline metallized pellets and carbon-based biomass to accelerate the flocculation of solid-phase substances, thereby further improving the separation effect of the oil, water and solid phases of the oily sludge.

[0025] Furthermore, the alkaline metallized pellets are composed of metallized pellets and hydroxides of alkali metals with a weight ratio of 100:(10 - 15).

[0026] In a specific embodiment, the weight ratio of the metallized pellets to the hydroxide can be 100:5, 100:10, 100:15, 100:20.

[0027] In some specific embodiments, the weight ratio of the metallized pellets to the hydroxide can also be 100:(5 - 10), 100:(5 - 15), 100:(10 - 20), 100:(10 - 20), 100:(15 - 20).

[0028] Through experimental analysis, it is known that when the weight ratio of the metallized pellets to the hydroxide is controlled within the above range, the treatment effect of the oily sludge can be further improved.

[0029] Preferably, the total iron content of the metallized pellets ≥ 40wt%.

[0030] The metallized pellets used in this application are pellets with a total iron content ≥ 40wt%. The source of the metallized pellets can be iron-containing ores such as iron ore concentrate, hematite, laterite nickel ore, etc.; the source of the metallized pellets can also be iron-containing solid wastes such as red mud and copper slag.

[0031] Preferably, the average particle size of the metallized pellets ≤ 1mm.

[0032] Furthermore, the hydroxides of alkali metals are selected from one or more of sodium hydroxide and potassium hydroxide.

[0033] Preferably, the polyacrylamide is non-ionic polyacrylamide.

[0034] During the experiment, the applicant found that compared with using cationic polyacrylamide or anionic polyacrylamide, the present application selects to use non-ionic polyacrylamide for sludge treatment, which can further improve the treatment effect of sludge; this may be because non-ionic polyacrylamide is not easily broken by the iron ions in the basic metallized pellets, will not reduce the flocculation effect of the basic metallized pellets, and non-ionic polyacrylamide, as an organic flocculant, can play a good compatibility role with the iron ions in the basic metallized pellets.

[0035] Furthermore, the concentration of the non-ionic polyacrylamide is 0.05-0.15 wt%.

[0036] In a specific embodiment, the concentration of the non-ionic polyacrylamide can be 0.05 wt%, 0.1 wt%, 0.15 wt%.

[0037] In some specific embodiments, the concentration of the non-ionic polyacrylamide can also be 0.05-0.1 wt%, 0.1-0.15 wt%.

[0038] Optionally, the carbon-based biomass is selected from one or more of wood chips, straws, sawdust, bagasse, rice bran.

[0039] Preferably, the method for treating sludge further includes the recycling of metallized pellets, and the specific method is as follows:

[0040] The solid phase obtained after sludge treatment is mixed with calcium oxide and then subjected to shaping treatment, and after roasting, solid-phase metallized pellets are obtained, which are crushed and ground, and are used to replace the addition of the metallized pellets.

[0041] After the sludge in the present application is treated, the main components of the obtained solid phase are metallized pellets and carbon-based biomass; therefore, the applicant mixes the solid phase with calcium oxide and then conducts shaping and roasting treatments. The obtained solid-phase metallized pellets can replace the metallized pellets used for the first time, and then the sludge is treated. That is, the metallized pellets used in the sludge mixing treatment stage of the present application can be recycled, greatly reducing the raw material cost in the method for treating sludge.

[0042] During the process of preparing solid-phase metallized pellets from the solid phase, the carbon-based biomass in the solid phase can play the role of reduction and heat source during the roasting process. While reducing iron oxide, it can also provide heat, which is beneficial to reducing the cost during the experiment. In addition, the calcium oxide added in the present application can promote the reduction of iron oxide in the solid phase and promote the formation and growth of iron grains.

[0043] Through experimental analysis, it can be seen that the effect of using iron concentrate metallized pellets is not as good as that of solid-phase metallized pellets, because the adsorption capacity and micro-electrolysis capacity of solid-phase metallized pellets are both better than those of iron concentrate metallized pellets.

[0044] Further, the weight ratio of the solid phase to the calcium oxide is 100:(2 - 10).

[0045] Further, the conditions for roasting are: the roasting temperature is 1100 - 1250 °C; the roasting time is 10 - 30 min.

[0046] In summary, the technical solution of this application has the following effects:

[0047] This application uses carbon-based biomass, alkaline metallized pellets and polyacrylamide to treat oily sludge, so that the aqueous phase, oil phase and solid phase in the oily sludge are well separated, effectively reducing the amount of oily sludge. The entire treatment process is simple to operate, and has the advantages of thorough treatment, rapid reaction, simple reaction conditions, convenient operation and low cost, and is suitable for industrial treatment of oily sludge.

[0048] Using the method for treating oily sludge provided by this application, the aqueous phase material after treating the oily sludge meets the requirements of the sewage treatment plant for the oil content and COD content in the water; the recovery rate of the oil phase material is relatively high, the water content in the oil phase material is relatively low, and the oil phase can enter the recycling system for recycling; and the oil content and water content of the solid phase are relatively low.

[0049] This application further improves the separation effect of the oil-water-solid three phases in the oily sludge by controlling the weight ratio of the alkaline metallized pellets, wood chips, polyacrylamide and oily sludge. Description of the Drawings

[0050] Figure 1 It is the specific process of the method for treating oily sludge in the embodiment of this application. Detailed Embodiments

[0051] This application provides a method for treating oily sludge, which specifically includes the following steps:

[0052] Use alkaline metallized pellets, carbon-based biomass and polyacrylamide to treat oily sludge,

[0053] wherein, the weight ratio of the alkaline metallized pellets, carbon-based biomass, polyacrylamide to the oily sludge is (20 - 30):(10 - 20):(2 - 5):100;

[0054] The alkaline metallized pellets are composed of metallized pellets and alkali metal hydroxides with a weight ratio of 100:(10 - 20).

[0055] The performance indicators of the treated oily sludge are as follows: water content > 95 wt%, oil content = 3 - 5 wt%.

[0056] Among them, in the treatment method of oily sludge, the addition order of each raw material is as follows:

[0057] First, add polyacrylamide to the oily sludge; then add a mixture of basic metallized pellets and carbon-based biomass.

[0058] Specifically, the total iron content of the metallized pellets ≥ 40 wt%, and the average particle size ≤ 1 mm.

[0059] The hydroxides of alkali metals are selected from one or more of sodium hydroxide and potassium hydroxide.

[0060] Meanwhile, the polyacrylamide is non-ionic polyacrylamide with a concentration of 0.05 - 0.15 wt%.

[0061] In addition, the carbon-based biomass is selected from one or more of wood chips, straws, sawdust, bagasse, and rice bran.

[0062] Furthermore, the treatment method of oily sludge also includes the recycling of metallized pellets:

[0063] The specific method is as follows: Mix the solid phase obtained after treating the oily sludge with calcium oxide at a weight ratio of 100:(2 - 10), then carry out shaping treatment, and after roasting, obtain solid-phase metallized pellets. After crushing and grinding, they are used to replace the addition of metallized pellets.

[0064] Furthermore, the conditions for roasting are: roasting temperature is 1100 - 1250 °C; roasting time is 10 - 30 min.

[0065] The following further describes the present application in detail with reference to examples, comparative examples, and performance detection tests. These examples should not be construed as limiting the scope claimed by the present application.

[0066] Sources of oily sludge treated in examples and comparative examples: Take the oily sludge after sewage treatment in a certain refinery as the oily sludge to be treated. The water content of this oily sludge is 95.03 wt%, the oil content is 4.00 wt%, and the solid content is 0.97 wt%.

[0067] Examples

[0068] Example 1

[0069] Example 1 provides a treatment method for oily sludge.

[0070] In the treatment method of oily sludge in the above example, it specifically includes the following steps:

[0071] The specific process of the treatment method of oily sludge is as Figure 1 shown, specifically:

[0072] S1: Mix 100 g of metallized pellets evenly with 10 g of sodium hydroxide to obtain alkaline metallized pellets for standby. Among them, the metallized pellets are iron concentrate powder with a total iron content of 50 wt% and an average particle size of 1 mm.

[0073] S2: Take 25 g of alkaline metallized pellets and mix them evenly with 15 g of wood chips to obtain mixture A.

[0074] Add 4 g of non-ionic polyacrylamide (CAS: 9003-05-8) with a concentration of 0.1 wt% to 100 g of oily sludge, stir evenly, and then add mixture A and mix evenly to obtain mixture B.

[0075] S3: Centrifuge the mixture B in step S2 to separate the oil-water mixture and the solid phase.

[0076] S4: Separate the oil and water in the oil-water mixture to obtain the oil phase and the water phase. The oil enters the recycling system; the qualified wastewater is sent to the sewage treatment workshop.

[0077] S5: Mix the solid phase with calcium oxide at a weight ratio of 100:5, then carry out molding treatment, and calcine at 1200 °C for 20 min after molding to obtain solid-phase metallized pellets. After crushing and grinding, it can be used as an additive to replace the iron concentrate powder in step S1.

[0078] Example 2-7

[0079] Examples 2-7 respectively provide a method for treating oily sludge.

[0080] The differences between the above examples and Example 1 are as follows: the weight ratios of alkaline metallized pellets, wood chips, polyacrylamide and oily sludge are specifically shown in Table 1.

[0081] Table 1 Weight ratios of alkaline metallized pellets, wood chips, polyacrylamide and oily sludge in Examples 1-7

[0082]

[0083]

[0084] Examples 8-10

[0085] Examples 8-10 respectively provide a method for treating oily sludge.

[0086] The differences between the above examples and Example 1 are as follows: the weight ratios of iron concentrate powder and sodium hydroxide in alkaline metallized pellets are specifically shown in Table 2.

[0087] Table 2 Weight ratios of iron concentrate powder and sodium hydroxide in Examples 1, 8-10

[0088]

[0089] Example 11

[0090] This example provides a method for treating oily sludge.

[0091] The difference between this example and Example 1 is that the concentration of non-ionic polyacrylamide is 0.2 wt%.

[0092] Example 12

[0093] This example provides a method for treating oily sludge.

[0094] The difference between this example and Example 1 is that cationic polyacrylamide (CAS: 25085-02-3) is used to replace the non-ionic polyacrylamide in step S2.

[0095] Example 13

[0096] This example provides a method for treating oily sludge.

[0097] The difference between this example and Example 1 is that anionic polyacrylamide (CAS: 62649-23-4) is used to replace the non-ionic polyacrylamide in step S2.

[0098] Example 14

[0099] This comparative example provides a method for treating oily sludge.

[0100] The difference between this comparative example and Example 1 is the addition order of each raw material. The method for treating oily sludge is specifically as follows:

[0101] S1: Mix 100 g of metallized pellets with 10 g of sodium hydroxide evenly to obtain alkaline metallized pellets for standby; among them, the metallized pellets are iron concentrate metallized pellets with a particle size of 1 mm and a total iron content of 50 wt%.

[0102] S2: Put 25 g of alkaline metallized pellets, 15 g of wood chips, and 4 g of non-ionic polyacrylamide with a concentration of 0.1 wt% into 100 g of oily sludge and stir evenly to obtain a mixture.

[0103] S3: Centrifuge the mixture in step S2 to separate the oil-water mixture and the solid phase.

[0104] S4: Separate the oil-water mixture to obtain an oil phase and a water phase. The oil enters the recycling system; the qualified wastewater is sent to the sewage treatment workshop.

[0105] Example 15

[0106] This embodiment provides a method for treating oily sludge.

[0107] The difference between this embodiment and Embodiment 1 is that the metallized pellet used in Step S1 is the solid-phase metallized pellet prepared in Step S5 of Embodiment 1; the total iron content of this solid-phase metallized pellet is 50 wt% and the particle size is 1 mm.

[0108] Comparative example

[0109] Comparative examples 1-3

[0110] Comparative examples 1-3 respectively provide a method for treating oily sludge.

[0111] The difference between the above comparative examples and Embodiment 1 is that the weight ratios of the alkaline metallized pellet, sawdust, polyacrylamide and oily sludge are specifically shown in Table 3.

[0112] Table 3 Weight ratios of alkaline metallized pellet, sawdust, polyacrylamide and oily sludge in Comparative examples 1-3

[0113]

[0114] Comparative example 4

[0115] This comparative example provides a method for treating oily sludge.

[0116] The difference between this comparative example and Embodiment 1 is that no sawdust is added, and the method for treating oily sludge is specifically as follows:

[0117] S1: Mix 100 g of metallized pellet with 10 g of sodium hydroxide evenly to obtain an alkaline metallized pellet for standby; among them, the metallized pellet is an iron concentrate metallized pellet with a particle size of 1 mm and a total iron content of 50 wt%.

[0118] S2: Add 4 g of non-ionic polyacrylamide with a concentration of 0.1 wt% to 100 g of oily sludge and stir evenly, then add 25 g of alkaline metallized pellet and stir evenly to obtain a mixture.

[0119] S3: Centrifuge the mixture in Step S2 to separate the oil-water mixture and the solid phase.

[0120] S4: Separate the oil and water in the oil-water mixture to obtain an oil phase and a water phase.

[0121] Comparative example 5

[0122] This comparative example provides a method for treating oily sludge.

[0123] The difference between this comparative example and Embodiment 1 is that no non-ionic polyacrylamide is added, and the method for treating oily sludge is specifically as follows:

[0124] S1: Mix 100 g of metallized pellets evenly with 10 g of sodium hydroxide to obtain basic metallized pellets for standby. Among them, the metallized pellets are iron concentrate metallized pellets with a particle size of 1 mm and a total iron content of 50 wt%.

[0125] S2: Take 25 g of basic metallized pellets and mix them evenly with 15 g of wood chips, then put them into 100 g of oily sludge. After mixing evenly, a mixture is obtained.

[0126] S3: Centrifuge the mixture in step S2 to separate the oil-water mixture and the solid phase.

[0127] S4: Separate the oil and water in the oil-water mixture to obtain the oil phase and the water phase.

[0128] Comparative Example 6

[0129] This comparative example provides a method for treating oily sludge.

[0130] The difference between this comparative example and Example 1 is that no basic metallized pellets and wood chips are added. The method for treating oily sludge is specifically as follows:

[0131] S1: Add 4 g of non-ionic polyacrylamide with a concentration of 0.1 wt% to 100 g of oily sludge and stir evenly to obtain a mixture.

[0132] S2: Centrifuge the mixture in step S2 to separate the oil-water mixture and the solid phase.

[0133] S3: Separate the oil and water in the oil-water mixture to obtain the oil phase and the water phase.

[0134] Comparative Example 7

[0135] This comparative example provides a method for treating oily sludge.

[0136] The difference between this comparative example and Example 1 is that polymeric ferric sulfate is used instead of basic metallized pellets. The method for treating oily sludge is specifically as follows:

[0137] S1: Take 25 g of polymeric ferric sulfate and mix it evenly with 15 g of wood chips to obtain mixture A;

[0138] Add 4 g of non-ionic polyacrylamide with a concentration of 0.1 wt% to 100 g of oily sludge, stir evenly, and then add mixture A and mix evenly to obtain mixture B.

[0139] S2: Centrifuge mixture B in step S2 to separate the oil-water mixture and the solid phase.

[0140] S3: Separate the oil and water in the oil-water mixture to obtain the oil phase and the water phase.

[0141] Comparative Example 8

[0142] This comparative example provides a method for treating oily sludge.

[0143] The difference between this comparative example and Example 1 is that ferrous sulfate is used instead of basic metalized pellets, and the method for treating oily sludge is specifically as follows:

[0144] S1: Take 25 g of ferrous sulfate and mix it evenly with 15 g of wood chips to obtain mixture A;

[0145] Add 4 g of non-ionic polyacrylamide with a concentration of 0.1 wt% to 100 g of oily sludge, stir evenly, and then add mixture A and mix evenly to obtain mixture B.

[0146] S2: Centrifuge the mixture B in step S2 to separate the oil-water mixture and the solid phase.

[0147] S3: Separate the oil and water in the oil-water mixture to obtain the oil phase and the water phase.

[0148] Performance detection test

[0149] Taking the oil phase and water phase obtained after treating the oily sludge in Examples 1-15 and Comparative Examples 1-8 as the detection objects, the performance indexes of the water phase, oil phase and solid phase are detected respectively.

[0150] The specific detection method is as follows:

[0151] Water phase: Weigh the recovery amount of the water phase, and detect the oil content in the water phase according to GB / T 16488-1996 "Determination of Petroleum and Vegetable and Animal Oils in Water - Infrared Photometric Method", and detect the COD content in the water phase according to GB / T 11914-1989 "Determination of Chemical Oxygen Demand in Water - Dichromate Method".

[0152] Oil phase: Weigh the recovery amount of the oil phase, detect the water content in the oil phase according to GB / T 11146-1999 "Method for Determination of Water Content in Crude Oil"; and calculate the recovery rate of oil in the oily sludge, and the recovery rate of oil = (recovery amount of oil phase - recovery amount of oil phase × water content of oil phase) / 4 × 100%.

[0153] Detection results: As shown in Table 4.

[0154] Table 4 Detection results of the water phase, oil phase and solid phase in Examples 1-15 and Comparative Examples 1-8

[0155]

[0156]

[0157] Combined with Table 4, by comparing the detection results of Examples 1-15 and Comparative Examples 1-8, the present application uses carbon-based biomass, alkaline metallized pellets and polyacrylamide to treat oily sludge. After centrifugally separating the solid and liquid phases and separating the oil and water in the liquid phase, the water phase, oil phase and solid phase in the oily sludge are well separated. After detection, the oil content in the water phase is lower than 0.49 wt%, and the COD content in the water phase is lower than 496 mg / L, meeting the requirements of the sewage treatment plant for the oil content and COD content in water; the water content in the oil phase is lower than 1.64 wt%, and the oil recovery rate in the oily sludge is higher than 84.64%, and it can enter the recycling system for recycling; the oil content in the solid phase is lower than 0.49%. In addition, the separated solid phase and calcium oxide are subjected to forming treatment and roasting to obtain solid-phase metallized pellets to replace iron concentrate metallized pellets, and then the oily sludge is treated for reuse. The above results show that the treatment method of oily sludge provided by the present application effectively improves the treatment effect of oily sludge.

[0158] By comparing the detection results of Example 1 and Comparative Example 4, compared with not adding wood chips as carbon-based biomass, the present application selects to add wood chips as carbon-based biomass, which can form a microelectrolysis reaction with alkaline metallized pellets, thereby being beneficial to improving the treatment effect of oily sludge.

[0159] By comparing the detection results of Example 1 and Comparative Example 5, compared with not adding non-ionic polyacrylamide, the present application selects to add polyacrylamide, which cooperates with carbon-based biomass and alkaline metallized pellets to treat oily sludge, and can significantly improve the treatment effect of oily sludge.

[0160] By comparing the detection results of Example 1 and Comparative Example 6, compared with not adding alkaline metallized pellets and carbon-based biomass, the present application selects to add alkaline metallized pellets and carbon-based biomass, which cooperate with non-ionic polyacrylamide to treat oily sludge, and can significantly improve the treatment effect of oily sludge.

[0161] By comparing the detection results of Example 1 and Comparative Examples 7-8, compared with using polymeric ferric sulfate or ferrous sulfate, the present application selects to use alkaline metallized pellets, which cooperate with carbon-based biomass and non-ionic polyacrylamide, and can further improve the treatment effect of oily sludge.

[0162] By comparing the detection results of Examples 1-7 and Comparative Examples 1-3, when controlling the weight ratio of alkaline metallized pellets, carbon-based biomass, polyacrylamide to oily sludge within the range of (20-30):(10-20):(2-5):100, the treatment effect of oily sludge can be significantly improved. Therefore, the present application controls the weight ratio of alkaline metallized pellets, carbon-based biomass, polyacrylamide to oily sludge within the above range.

[0163] By comparing the test results of Example 1 with those of Examples 8-10, when the weight ratio of the metallized pellets to the alkali metal hydroxide in the alkaline metallized pellets is controlled within the range of 100:(5-20), the sludge treatment effect can be further improved. Therefore, the present application controls the weight ratio of the metallized pellets to the alkali metal hydroxide within the above range.

[0164] By comparing the test results of Example 1 with those of Examples 11-12, compared with the use of cationic polyacrylamide or anionic polyacrylamide, the present application chooses to use nonionic polyacrylamide, which can further improve the treatment effect of sludge. At the same time, by comparing the test results of Example 1 with those of Example 13, when the concentration of nonionic polyacrylamide is controlled in the range of 0.05-0.15wt%, the treatment effect of sludge can be further improved. Therefore, the present application chooses to use nonionic polyacrylamide, and controls the concentration of nonionic polyacrylamide within the above range.

[0165] By comparing the test results of Example 1 and Example 14, when the alkaline metallized pellets, wood chips and non-ionic polyacrylamide are put into the oil sludge together, the treatment effect of the oil sludge is poor; however, the present application chooses to first fully mix the oil sludge and non-ionic polyacrylamide, and then add the mixture of alkaline metallized pellets and carbon-based biomass, which can further improve the treatment effect of the oil sludge.

[0166] By combining the test results of Example 1 and Example 15, the present application uses the solid phase metallized pellets of Example 1 as the source of metallized pellets and treats the oil sludge, and the treatment effect of the oil sludge is better than the treatment effect of the iron concentrate metallized pellets. It can be seen that the metallized pellets used in the oil sludge mixing treatment stage of the present application can be reused, achieving the beneficial effect of recycling and low-cost treatment of oil sludge.

[0167] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A method for treating sludge, characterized in that, Specifically, it includes the following steps: Treat the oily sludge with alkaline metallized pellets, carbon-based biomass, and non-ionic polyacrylamide. The performance indicators of the oily sludge are water content > 95wt% and oil content = 3 - 5wt%. Among them, the weight ratio of the alkaline metallized pellets, the carbon-based biomass, the non-ionic polyacrylamide to the oily sludge is (20 - 30):(10 - 20):4:100; the carbon-based biomass is wood chips. The alkaline metallized pellets are composed of metallized pellets and alkali metal hydroxides with a weight ratio of 100:(5 - 20); the total iron content of the metallized pellets is ≥ 40wt%. In the treatment method of the oily sludge, the addition order of each raw material is: First, add the non-ionic polyacrylamide to the oily sludge and mix evenly; then add the mixture of the alkaline metallized pellets and the carbon-based biomass. The treatment method of the oily sludge also includes the recycling of the metallized pellets. The specific method is: Mix the solid phase obtained after treating the oily sludge with calcium oxide, carry out shaping treatment, and after roasting, obtain solid-phase metallized pellets. After crushing and grinding, replace the addition of the metallized pellets.

2. The treatment method of sludge according to claim 1, wherein, The alkaline metallized pellets are composed of metallized pellets and alkali metal hydroxides with a weight ratio of 100:(10 - 15).

3. The method for treating sludge according to claim 1, wherein The average particle size of the metallized pellets is ≤ 1mm.

4. The treatment method of sludge according to claim 1, characterized in that, The concentration of the non-ionic polyacrylamide is 0.05 - 0.15wt%.

5. The treatment method of sludge according to claim 1, characterized in that, The weight ratio of the solid phase to the calcium oxide is 100:(2 - 10).

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