Scum cleaning agent and preparation method thereof

Abstract

The invention belongs to the technical field of petrochemical industry, and discloses a scum cleaning agent and a preparation method thereof, and the preparation method comprises the following steps: adding an emulsifier, a cleaning auxiliary agent and a chelating agent into a stirring tank according to a ratio of 1: 10: 1 until the materials are completely and uniformly stirred to prepare an oil sludge cleaning agent A; the ratio of the demulsifying agent to the flocculating agent to the water is 1: 1: 8; adding water into the demulsifying agent mixed solution and the flocculating agent, and stirring at normal temperature to prepare an oil sludge cleaning agent B; the agent A and the agent B are mixed to obtain the scum cleaning agent. According to the invention, scum oil sludge can be treated by adopting a chemical thermal washing process, and resource utilization and crude oil recovery are realized. The treated residual solid phase meets the industrial standard of SY / T7301-2016 Technical Requirements for Resource Comprehensive Utilization and Pollution Control of Oily Sludge in Land Oil and Natural Gas Exploitation, and the total amount of petroleum hydrocarbon is not greater than 2%. A chemical thermal washing process is adopted to replace a cracking process, so that the treatment cost is reduced.

Description

Technical Field

[0001] This invention relates to solid waste treatment in the petrochemical field, specifically the comprehensive utilization of oily sludge during oil extraction to meet pollution control technical requirements. It also relates to the preparation of scum-oil sludge separation agents, and more specifically, to a scum cleaning agent and its preparation method. Background Technology

[0002] The extraction, gathering, transportation, refining, and treatment of oily wastewater generate large quantities of black, oily solid and semi-solid waste, known as oily sludge or simply oil sludge. Its main components are oil, mud, and water. The particle size of oil sludge can range from less than a micrometer to several inches, with most particles between 1 and 100 micrometers. Preliminary surveys indicate that my country's annual increase in oily sludge production reaches approximately 800,000 tons. Because oil sludge contains water, sediment, sulfides, benzene compounds, phenols, and hydrocarbons, it not only occupies land and space but also severely pollutes the air, soil, and groundwater, thus hindering the development of domestic oilfield production to some extent. In the 2016 National Hazardous Waste List, oily sludge was classified as HW08 waste mineral oil and mineral oil-containing waste.

[0003] The crude oil extraction blocks in the Liaohe River region produce extra-heavy and extra-large crude oils, with a high proportion of gums and asphaltenes in the crude oil composition. The oil sludge and scum are mainly produced by air flotation in the wastewater treatment stage of the combined treatment plant after flocculant is added, followed by dehydration using a centrifuge. It has high oil and solids content, a complex composition, and high viscosity, containing not only large amounts of sludge but also heavy metals, sulfides, gums, and asphaltenes. The oil, water, and sludge are tightly bound together, exhibiting stable properties, making chemical and thermal washing difficult, and existing technologies lack effective treatment agents. Summary of the Invention

[0004] Current methods for treating scum and oil sludge do not involve chemical thermal washing to achieve resource utilization and solve the problem of high cost of thermal pyrolysis treatment of scum and oil sludge.

[0005] This invention aims to overcome the limitations of chemical thermal washing methods in treating oily sludge and sludge, enabling its resource utilization. Addressing the problems of low oil washing efficiency and incomplete cleaning in existing oilfield sludge cleaning agents, this invention provides an oilfield sludge cleaning agent with an oil washing efficiency as high as 95-98%. This invention also provides a method for preparing the oilfield sludge cleaning agent.

[0006] The technical solution of the present invention is as follows:

[0007] A scum cleaning agent, the components and proportions of which are as follows by weight percentage: emulsifier 1-5%, cleaning aid 10-30%, demulsifier 1-5%, chelating agent 1-5%, solubilizer 0.5-2%, flocculant 1-3%, and the balance being water.

[0008] The emulsifier is a medium-splitting asphalt emulsifier.

[0009] The detergent additive is sodium chloride.

[0010] The solubilizer is methanol.

[0011] The demulsifier is AE-1901.

[0012] The chelating agent is EDTA-2Na.

[0013] The flocculant is polyacrylamide, prepared as a 1% aqueous solution.

[0014] This invention also provides a method for preparing a scum cleaning agent, comprising the following steps:

[0015] Agent A: Add emulsifier, cleaning aid, and chelating agent to a mixing tank in a ratio of 1:10:1 until completely mixed to prepare sludge cleaning agent Agent A.

[0016] Agent B: Composed of demulsifier, flocculant, and water in a ratio of 1:1:8; the flocculant, polyacrylamide, is a 1% aqueous solution, and the demulsifier is a mixture prepared by adding AE1901, methanol, and water in a ratio of 62:33:5 sequentially into a reaction vessel at a water temperature of 40℃ and a stirring time of 40 minutes at a stirring speed of 60-90 rpm; the demulsifier mixture and polyacrylamide aqueous solution are stirred with water at room temperature to prepare the sludge cleaning agent Agent B.

[0017] The cleaning agent contains the following components:

[0018] The medium-crack asphalt emulsifier, as a cationic surfactant, can emulsify the gum and asphaltenes of scum and sludge, greatly reducing the surface tension of the oil-water interface. It has the effects of wetting and penetrating, suspension and dispersion, and minimal damage to cleaning. Moreover, it often has a significant emulsifying effect even at very low concentrations of surfactant.

[0019] The methanol is a solubilizer, which makes the demulsifier readily available in water;

[0020] The sodium chloride is a detergent builder that can balance the hydrophilicity and lipophilicity of surfactants, increase the density of water, increase the density difference between oil and water, and improve centrifugation efficiency. High concentrations of electrolytes can promote demulsification efficiency.

[0021] The EDTA-2Na is a chelating agent that can chelate heavy metals in scum and sludge, reducing the coordination force between metal ions and crude oil components.

[0022] The polyacrylamide is a flocculant with a cationic degree of 60. It neutralizes the charge of emulsified oil droplets in water and compresses the double electric layer, thus playing a role in colloidal flocculation.

[0023] AE1901 is a demulsifier. The AE type is a two-stage, multi-branched crude oil demulsifier, suitable for demulsifying asphalt-based crude oil emulsions. The higher the content of lipophilic surfactants in asphalt-based crude oil, the stronger the viscosity, the smaller the oil-water density difference, and the less prone it is to demulsification. However, the AE type demulsifier provides rapid demulsification, and it is also a good anti-waxing and viscosity-reducing agent.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. This invention enables the treatment of floating sludge and oil sludge using a chemical thermal washing process, thereby achieving resource utilization and crude oil recovery.

[0026] 2. The remaining solid phase after treatment according to the present invention meets the industry standard SY / T7301-2016 "Technical Requirements for Comprehensive Utilization and Pollution Control of Oily Sludge from Onshore Oil and Gas Extraction", and the total amount of petroleum hydrocarbons should not exceed 2%.

[0027] 3. The chemical thermal washing process was used instead of the pyrolysis process, which reduced the processing cost. Attached Figure Description

[0028] Figure 1 This is a sample image of the sample obtained in Example 1 with a remaining solid petroleum hydrocarbon content of 1.44%. Detailed Implementation

[0029] The present invention is described in detail below through specific embodiments, but this does not limit the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can all be obtained commercially.

[0030] A high-colloid, asphalt-based sludge cleaning agent, the components and proportions of which are as follows by weight percentage: emulsifier 2%, cleaning aid 20%, demulsifier 2%, chelating agent 2%, solubilizer 1%, flocculant 2%, and the balance being water.

[0031] The emulsifier is a medium-splitting asphalt emulsifier, the washing aid is sodium chloride, the solubilizer is methanol, the demulsifier is AE-1901, the chelating agent is EDTA-2Na, and the flocculant is polyacrylamide (1% aqueous solution).

[0032] This invention also provides a method for preparing high-colloidal, asphaltene sludge cleaning agents A and B, comprising the following steps:

[0033] Agent A: Add emulsifier, cleaning aid, and chelating agent to a mixing tank in a ratio of 1:10:1 until completely mixed to prepare sludge cleaning agent Agent A.

[0034] Agent B: Composed of demulsifier, flocculant, and water in a ratio of 1:1:8; the flocculant, polyacrylamide, is a 1% aqueous solution, and the demulsifier is a mixture prepared by adding AE1901, methanol, and water in a ratio of 62:33:5 sequentially into a reaction vessel at a water temperature of 40℃ and a stirring time of 40 minutes at a stirring speed of 60-90 rpm; the demulsifier mixture and polyacrylamide aqueous solution are stirred with water at room temperature to prepare the sludge cleaning agent Agent B.

[0035] The components of this high-colloidal, asphalt-based sludge cleaning agent are as follows:

[0036] The medium-crack asphalt emulsifier, as a cationic surfactant, can emulsify the gum and asphaltenes of scum and sludge, greatly reducing the surface tension of the oil-water interface. It has the effects of wetting and penetrating, suspension and dispersion, and minimal damage to cleaning. Moreover, it often has a significant emulsifying effect even at very low concentrations of surfactant.

[0037] The methanol is a solubilizer, which makes the demulsifier readily available in water;

[0038] The sodium chloride is a detergent builder that can balance the hydrophilicity and lipophilicity of surfactants, increase the density of water, increase the density difference between oil and water, and improve centrifugation efficiency. High concentrations of electrolytes can promote demulsification efficiency.

[0039] The EDTA-2Na is a chelating agent that can chelate heavy metals in scum and sludge, reducing the coordination force between metal ions and crude oil components.

[0040] The polyacrylamide is a flocculant with a cationic degree of 60. It neutralizes the charge of emulsified oil droplets in water and compresses the double electric layer, thus playing a role in colloidal flocculation.

[0041] AE1901 is a demulsifier. The AE type is a two-stage, multi-branched crude oil demulsifier, suitable for demulsifying asphalt-based crude oil emulsions. The higher the content of lipophilic surfactants in asphalt-based crude oil, the stronger the viscosity, the smaller the oil-water density difference, and the less prone it is to demulsification. However, the AE type demulsifier provides rapid demulsification, and it is also a good anti-waxing and viscosity-reducing agent.

[0042] Example 1

[0043] Agent A: Add emulsifier, detergent builder, and chelating agent to a mixing tank in a ratio of 1:10:1 until completely mixed to prepare Agent A for cleaning sludge. The dosage is 5-9% of the sludge with a water content of 50-70%.

[0044] Agent B: Composed of demulsifier, polyacrylamide, and water in a ratio of 1:1:8. The demulsifier is a mixture prepared by adding AE1901, methanol, and water in a ratio of 62:33:5 sequentially into a reaction vessel at a water temperature of 40℃ and a stirring time of 40 minutes at a stirring speed of 60-90 rpm. The polyacrylamide is a 1% aqueous solution. Agent B is used to prepare the sludge cleaning agent, and the amount added is 15-20% of the sludge containing 50-70% water.

[0045] The properties of the sludge from a certain oil sludge plant are as follows: oil content 39.5%, water content 48.4%, solids content 12.1% (percentages by weight). The crude oil composition consists of 9.1% asphaltenes and 81.9% gums.

[0046] The sludge was pumped into a mixing tank to achieve a solid-liquid ratio of 1:3 between sludge and water. After vigorous stirring for 10 minutes, the sludge and water were thoroughly mixed. The sludge cleaning agent obtained in Example 1 was added to the mixing tank at 6% of the sludge weight. The reaction temperature was maintained at 75-85°C, and the stirring time was 60 minutes. The reaction product was then separated into oil, water, and sludge in an oil sludge separation device, with the remaining solid petroleum hydrocarbons totaling 1.44%.

[0047] The embodiments described above are merely preferred embodiments of the present invention, and not all feasible embodiments of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A scum cleaning agent, characterized in that, The components and proportions by weight percentage are as follows: Emulsifier 1-5%, cleaning aid 10-30%, demulsifier 1-5%, chelating agent 1-5%, solubilizer 0.5-2%, flocculant 1-3%, balance is water.

2. The scum cleaning agent according to claim 1, characterized in that, The emulsifier is a medium-splitting asphalt emulsifier.

3. The scum cleaning agent according to claim 1, characterized in that, The detergent additive is sodium chloride.

4. The scum cleaning agent according to claim 1, characterized in that, The solubilizer is methanol.

5. The scum cleaning agent according to claim 1, characterized in that, The demulsifier is AE-1901.

6. The scum cleaning agent according to claim 1, characterized in that, The chelating agent is EDTA-2Na.

7. The scum cleaning agent according to claim 1, characterized in that, The flocculant is polyacrylamide, prepared as a 1% aqueous solution.

8. A method for preparing a scum cleaning agent, characterized in that, Includes the following steps: Agent A: Add emulsifier, cleaning aid and chelating agent to the mixing tank in the ratio of 1:10:1 and mix until completely mixed to make sludge cleaning agent Agent A; Agent B: Composed of demulsifier, flocculant and water in a ratio of 1:1:8; Agent B is prepared by mixing the demulsifier mixture and flocculant with water at room temperature. The mixture of Agent A and Agent B is a scum cleaning agent.

9. The method for preparing the scum cleaning agent according to claim 8, characterized in that, The demulsifier is a mixture prepared by adding AE1901, methanol, and water in a ratio of 62:33:5 into a reaction vessel at a water temperature of 40℃ and a stirring time of 40 minutes at a stirring speed of 60-90 rpm.

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