Alkali and salt resistant elution demulsifier and application thereof in direct pressure filtration treatment of oil sludge

Abstract

The application discloses an alkali-resistant and salt-resistant elution demulsifier and application thereof in direct pressure filtration treatment of oil sludge, and belongs to the field of oil sludge treatment. The elution demulsifier is composed of AR type phenol formaldehyde resin polyether and lauryl hydroxyl sulfobetaine LHSB, and the weight ratio is 9:1 to 6:4. The elution demulsifier has high salt-resistant and alkali-resistant capacity and wide spectrum adaptability, does not need to change raw material selection due to the change of oil sludge properties, and can make oil and water separate from the solid phase synchronously through the filter cloth under normal temperature conditions without pre-separating the oil phase, effectively solves technical problems such as paste filtration, oil wrapping and dehydration difference in the no-oil skimming direct pressure filtration process, can realize the separation of oil and water from the solid phase, and can be widely applied to the treatment of tank bottom oil sludge and high-silt production liquid crude oil.

Description

Technical Field

[0001] This invention belongs to the field of oil sludge treatment, specifically relating to an alkali- and salt-resistant eluent and its application in direct pressure filtration treatment of oil sludge. Background Technology

[0002] Tank bottom sludge is a colloidal three-phase system formed by the settling of heavy components, mud, and inorganic salts after crude oil and refined oil storage tanks have been left to stand for a long time. The conventional components generally account for 20% to 70% oil, 20% to 35% water, and 5% to 15% solid inorganic impurities (mud, colloids, asphaltenes, paraffin, sulfides, heavy metal salts, and corrosive products, etc.).

[0003] Crude oil with high sediment content contains formation sand and clay particles, with a high proportion of fine clay and high salt content. The sediment solid phase generally accounts for 5% to 50%, forming a stable and viscous emulsified sludge. The fine clay particles are stably adsorbed at the oil-water interface, strengthening the emulsion film and significantly increasing the difficulty of demulsification and sand removal. The sludge as a whole is a high-viscosity non-Newtonian pseudoplastic fluid, with a viscosity of several thousand to tens of thousands of mPa·s at room temperature. It is extremely prone to caking when stationary, forming a dense composite emulsion structure of oil and water. Asphaltenes and gums act as natural emulsifiers. Conventional static standing cannot break the emulsion. Under pressure, the colloidal skeleton collapses, the pores of the sludge cake close rapidly, and the efficiency of conventional pressing and dehydration is greatly reduced.

[0004] Currently, oil sludge treatment is mainly divided into conditioning and centrifugal separation, thermochemical washing and pressure filtration separation, and anaerobic pyrolysis separation. Among them, the direct pressure filtration process without skimming has become the mainstream compact process due to its small footprint and short process. However, this process omits the pre-skimming step, and the emulsified oil enters the pressure filtration system throughout the process. Problems such as clogging, oil coating, and poor dehydration are amplified, which puts higher demands on the demulsifying and conditioning agent system. Moreover, the oil sludge at the bottom of the tank has a wide range of sources and significant compositional fluctuations. Oil sludge from complex sources such as residual oil sludge from tertiary chemical flooding may itself be in a state of high alkalinity, high salinity, and high chemical agent residue. Existing conventional elution demulsifiers cannot adapt to the above working environment. Therefore, there is a need for an elution demulsifier with high salt and alkali resistance and broad-spectrum adaptability to meet the operational requirements of the direct pressure filtration process without skimming. Summary of the Invention

[0005] The purpose of this invention is to provide an elution-type demulsifier with strong salt and alkali resistance and broad-spectrum adaptability.

[0006] The specific technical solution of this invention is as follows:

[0007] An alkali- and salt-resistant eluent demulsifier, wherein the eluent demulsifier is compounded from AR-type phenolic resin polyether and lauryl hydroxysulfonyl betaine (LHSB); the weight ratio of AR-type phenolic resin polyether to lauryl hydroxysulfonyl betaine (LHSB) is 9:1-6:4.

[0008] Preferably, the AR-type phenolic resin polyether is a multi-branched nonionic polymer polyether obtained by block polymerization of propylene oxide and ethylene oxide under alkaline catalysis using alkylphenol-formaldehyde condensation multi-branched phenolic resin as an initiator; the AR-type phenolic resin polyether has a multi-branched aromatic core skeleton and PO-EO block flexible side chains.

[0009] Preferably, the alkyl group of the alkylphenol-formaldehyde condensation polyphenolic resin is selected from any one or more of p-tert-butylphenol, octylphenol, nonylphenol, or cashew phenol.

[0010] The AR-type phenolic resin polyether has 3 to 6 active hydroxyl groups; the molecular weight of the AR-type phenolic resin polyether is 5000 to 20000.

[0011] Preferably, the structural formula of lauryl hydroxysulfonate betaine (LHSB) is as follows:

[0012] ;

[0013] The lauryl hydroxysulfonate betaine (LHSB) is a sulfonate betaine without an amide structure or a carboxyl structure.

[0014] Preferably, the elution-type demulsifier is in undiluted form or diluted to an aqueous solution of 10% to 80% by weight.

[0015] Application of an alkali- and salt-resistant eluent demulsifier in direct pressure filtration of oily sludge, the application including:

[0016] The elution-type demulsifier is mixed with the oil sludge to be treated for conditioning treatment. Then, the conditioned oil sludge is subjected to plate and frame filter press filtration, so that the oil and water can pass through the filter cloth and be separated from the solid phase in one step.

[0017] Preferably, the sludge to be treated is bottom sludge from tanks or crude oil with high sediment content.

[0018] Preferably, the dosage of the elution-type demulsifier is 0.2 to 5.0 kg / m³ of sludge.

[0019] Preferably, the application further includes adding lime, coagulant and flocculant to the sludge after mixing the eluting demulsifier with the sludge to be treated.

[0020] The beneficial effects of this invention are as follows:

[0021] The elution-type demulsifier of the present invention is formulated with AR-type phenolic resin polyether and lauryl hydroxysulfonate betaine (LHSB). Through the combination of AR-type phenolic resin polyether and lauryl hydroxysulfonate betaine (LHSB), the elution-type demulsifier of the present invention has strong salt and alkali resistance and broad-spectrum adaptability. It does not require changing the raw material selection due to changes in the properties of oil sludge, and can fully meet the needs of various more complex oil sludge treatment systems and is convenient for production and use.

[0022] Meanwhile, the elution-type demulsifier of the present invention does not require pre-separation of the oil phase. It can be used to condition the oil sludge as a whole by using lime, coagulant and flocculant, and meet the process requirements of separating oil and water together through the filter cloth under normal temperature conditions. It effectively solves the technical problems such as caking, oil coating and poor dehydration in the direct pressure filtration process without skimming.

[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention will be described in detail below. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1

[0026] This embodiment provides an eluent-type demulsifier, which is composed of AR-type phenolic resin polyether and lauryl hydroxysulfonate betaine (LHSB), wherein the weight ratio of AR-type phenolic resin polyether to lauryl hydroxysulfonate betaine (LHSB) is 9:1.

[0027] The AR-type phenolic resin polyether is selected from multi-branched nonionic polymeric polyethers obtained by block polymerization of propylene oxide and ethylene oxide under alkaline catalysis using p-tert-butylphenol-formaldehyde condensation multi-branched phenolic resin as the initiator. It has 3 to 6 active hydroxyl groups, forming a multi-branched three-dimensional structure, as well as multiple aromatic core skeletons and PO-EO block flexible side chains. The hydrophilic-lipophilic balance value is precisely controlled by the EO / PO ratio, and the molecular weight is generally 5,000 to 20,000, which distinguishes it from other types of polyethers.

[0028] The structural formula of lauryl hydroxysulfonyl betaine (LHSB) is as follows: ;

[0029] The lauryl hydroxysulfonate betaine (LHSB) is a sulfonate betaine without amide or carboxyl structures. It has low viscosity, is easy to formulate, and has no long branched amide chains. It is not prone to thickening or gelling, making it suitable for compound systems with high additive content.

[0030] Among all betaine product systems, non-amide sulfonate betaine has the highest level of resistance to hard water and alkali. Therefore, there is no need to consider changing the raw material selection due to changes in the properties of oil sludge. It can fully meet the needs of various complex oil sludge treatment systems and is convenient for production and use.

[0031] The two raw materials, AR-type phenolic resin polyether and lauryl hydroxysulfonate betaine (LHSB), are mixed evenly at room temperature according to the weight ratio described above. They can be used directly as the stock solution or diluted into a 10-80% aqueous solution.

[0032] Example 2

[0033] This embodiment provides an application of an elution-type demulsifier in direct pressure filtration of oily sludge, wherein the elution-type demulsifier adopts the formulation described in Example 1.

[0034] When using a direct pressure filtration process without skimming to treat oily sludge at the bottom of a tank, it is required that oil and water pass through the filter cloth together, while the solid components are retained in the filter cloth, and the oil residue in the sludge cake is minimized.

[0035] Therefore, the demulsifier is required to reverse the lipophilicity of the solid phase to hydrophilicity, so that the oil can be washed out from the solid phase. The oil will not quickly aggregate but will be uniformly dispersed into fine particles with the aqueous phase. The size of these particles is smaller than the pores of the filter cloth, so that the oil and water can pass through the filter cloth together. At the same time, the filter cloth is required to maintain a lower lipophilicity under the action of the demulsifier, so that the pores of the filter cloth will not be stuck and blocked by the oil, allowing the liquid to pass through quickly.

[0036] In practical applications, the elution-type demulsifier of Example 1 is mixed with the oil sludge to be treated for conditioning. The AR-type phenolic resin polyether as the main agent has an aromatic core structure that is easily combined with the core framework of the fused aromatic rings (benzene ring, naphthalene ring, phenanthrene ring) of the colloid in the oil sludge and the highly fused aromatic sheets of the asphaltenes through π-π stacking. Moreover, the PO and EO structures effectively regulate the hydrophilic and lipophilic balance. By disintegrating the colloid-asphalt composite interface film, hydrogen bonds and van der Waals forces are used to self-assemble and form nanoscale aggregates (micelles). The strong interfacial competitive adsorption capacity rapidly reduces the solid-oil interface adhesion, peels off the oil bound to the solid surface, and converts the solid oil-coated material into an aqueous dispersed oil.

[0037] As an excipient, lauryl hydroxysulfonate betaine (LHSB) is an amphoteric surfactant. Its weak positive charge helps neutralize the anionic charge that may be present in the sludge, preventing strong flocculation. In particular, it compensates for the weaknesses of alkylphenol resin polyethers when treating crude oil sludge from chemical flooding. At the same time, due to its strong dispersing ability, it can destroy the wax crystal network structure and eliminate the solid phase particle stabilization effect. It not only helps to improve the demulsification ability of alkylphenol resin polyether as the main agent, but also limits the rapid aggregation of oil after demulsification, maintains the dispersion ability of oil and water, helps to improve the hydrophilicity of the filter cloth and reduce its oleophilicity, and enhances the ability of oil and water to pass through the filter cloth in a coordinated manner.

[0038] After being treated with a demulsifier, a suitable proportion of lime, coagulant, flocculant, etc. are added to the oil sludge system for in-depth conditioning. The purpose of conditioning is to achieve higher filter press efficiency, better cake dryness, and lower oil content in the cake. Then, the cake is sent to a plate and frame filter press for filtration, allowing the oil and water to pass through the filter cloth and be separated from the solid phase in one pass.

[0039] Depending on the properties of the sludge, the dosage of elution-type demulsifier is generally 0.5-5.0 kg / m³. The specific dosage can be determined by sampling and testing on-site. The method for determining the dosage is very simple and direct: observe that there is no obvious residue on the walls of the test sample bottle after treatment with elution-type demulsifier. At this point, the minimum dosage can be easily confirmed without the need for complicated testing equipment and a longer testing cycle.

[0040] AR-type alkylphenol resin polyethers used as the main agent are not limited to a single type. Because oil sludge comes from a wide range of sources and has significant differences in properties, the applicability can be determined by comparative tests of different sub-types based on the properties of the oil sludge being treated at the time. Then, gradient comparative tests can be conducted with LHSB as an auxiliary agent at different ratios to determine the optimal compounding ratio.

[0041] Meanwhile, the most direct manifestation of the strong complementary function of the main agent and the auxiliary agent is that the oil sludge can be conditioning as a whole by using lime, coagulant and flocculant without the need to separate the oil phase in advance. It can also separate the oil and water together through the filter cloth under normal temperature conditions. Heating the oil sludge to 40-60℃ is even better, and it can reduce the dosage of the agent and shorten the treatment time.

[0042] The oil sludge to be treated is tank bottom oil sludge or crude oil with high sediment content. The conventional composition of tank bottom oil sludge is generally 20% to 70% oil, 20% to 35% water, and 5% to 15% solid inorganic impurities. The sediment solid phase of crude oil with high sediment content generally accounts for 5% to 50%. Fine clay particles are stably adsorbed at the oil-water interface to strengthen the emulsion film.

[0043] The AR-type phenolic resin polyether in the elution-type demulsifier of this invention has high salt and alkali resistance. Laurethyl hydroxysulfonate betaine (LHSB) is stable in an ultra-wide pH range of 1.5 to 13.5, does not precipitate in high salt, and does not deactivate in hard water. Among all betaine products, including those with and without amide groups, as well as carboxylic betaine and sulfonic acid betaine, only sulfonic acid betaine without amide groups has superior salt and alkali resistance. That is, amide-free sulfonic acid betaine has the top level of hard water and alkali resistance. Therefore, there is no need to change the raw material selection due to changes in the properties of oil sludge, which can meet the needs of various more complex oil sludge treatment systems and is convenient for production and use.

[0044] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An alkali- and salt-resistant emulsifier, characterized in that, The elution-type demulsifier is composed of AR-type phenolic resin polyether and lauryl hydroxysulfonyl betaine (LHSB); the weight ratio of AR-type phenolic resin polyether to LHSB is 9:1-6:

4.

2. The alkali- and salt-resistant eluent demulsifier according to claim 1, characterized in that, The AR-type phenolic resin polyether is a multi-branched nonionic polymer polyether obtained by block polymerization of propylene oxide and ethylene oxide under alkaline catalysis, using alkylphenol-formaldehyde condensation multi-branched phenolic resin as the initiator; the AR-type phenolic resin polyether has a multi-branched aromatic core skeleton and PO-EO block flexible side chains.

3. The alkali- and salt-resistant eluent demulsifier according to claim 2, characterized in that, The alkyl group of the alkylphenol-formaldehyde condensation polybranched phenolic resin is selected from any one or more of p-tert-butylphenol, octylphenol, nonylphenol or cashew phenol. The AR-type phenolic resin polyether has 3 to 6 active hydroxyl groups; the molecular weight of the AR-type phenolic resin polyether is 5000 to 20000.

4. The alkali- and salt-resistant eluent demulsifier according to claim 1, characterized in that, The structural formula of lauryl hydroxysulfonyl betaine (LHSB) is as follows: ； The lauryl hydroxysulfonate betaine (LHSB) is a sulfonate betaine without an amide structure or a carboxyl structure.

5. The alkali- and salt-resistant eluent demulsifier according to claim 1, characterized in that, The elution-type demulsifier is in undiluted form or diluted to an aqueous solution of 10% to 80% by weight.

6. The application of an alkali- and salt-resistant eluent demulsifier as described in any one of claims 1 to 5 in direct pressure filtration of oily sludge, characterized in that, The applications include: The elution-type demulsifier is mixed with the oil sludge to be treated for conditioning treatment. Then, the conditioned oil sludge is subjected to plate and frame filter press filtration, so that the oil and water can pass through the filter cloth and be separated from the solid phase in one step.

7. The application of the alkali- and salt-resistant eluent demulsifier according to claim 6 in direct pressure filtration of oily sludge, characterized in that, The sludge to be treated is bottom sludge from tanks or crude oil with high sediment content.

8. The application of the alkali- and salt-resistant eluent demulsifier according to claim 6 in direct pressure filtration of oily sludge, characterized in that, The dosage of the elution-type demulsifier is 0.2–5.0 kg / m³ of sludge.

9. The application of the alkali- and salt-resistant eluent demulsifier according to claim 6 in direct pressure filtration of oil sludge, characterized in that, It also includes adding lime, coagulant and flocculant to the sludge after mixing the eluting demulsifier with the sludge to be treated.

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