Preparation and application of sewage corrosion inhibitor

Abstract

The invention relates to the technical field of petrochemical engineering, in particular to preparation and application of a sewage corrosion inhibitor. The preparation method comprises the steps that 1, triethanolamine and phosphoric acid react to prepare a phosphate corrosion inhibitor; step 2, carrying out block copolymerization on ethylene oxide and propylene oxide to synthesize PEO-PPO-PEO (Polyethylene Oxide-Polyphenylene Oxide-Polyethylene Oxide); step 3, modifying the ZnO or ZrSiO4 nano particles through a silane coupling agent; and 4, mixing the components with the bio-based solvent, and uniformly stirring to obtain the corrosion inhibitor. The preparation method of the high-salinity sewage corrosion inhibitor provided by the invention has the following advantages: high efficiency: the corrosion inhibition efficiency is greater than or equal to 95%, and the high-salinity sewage corrosion inhibitor is suitable for environments with high-concentration salinity, chloride ions and sulfate ions. The multifunctional scale inhibitor has the triple functions of corrosion inhibition, scale inhibition and dispersion. Environment friendliness: a bio-based solvent and low-toxicity raw materials are used, so that the coating is more environment-friendly.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical industry, in particular to the preparation and application of a sewage corrosion inhibitor. Background Art

[0002] Highly mineralized wastewater is widely found in petrochemical industry, oilfield water injection and industrial wastewater treatment. High concentrations of salt and chloride ions (Cl - ), sulfate ion (SO4 2- ) can accelerate the corrosion of metal equipment. This corrosion not only shortens equipment life but also increases maintenance costs. Traditional corrosion inhibitors are difficult to maintain long-term stability and effectiveness in high-salinity and high-mineralization environments and may cause environmental pollution.

[0003] The international community has made some progress in the research and development of high-mineralization corrosion inhibitors, but there are still some shortcomings. For example:

[0004] U.S. Patent US20230234567A1 provides a corrosion inhibitor based on quaternary ammonium salt, but its environmental performance is poor;

[0005] Japanese patent JP2023054321A proposes a polymer-modified corrosion inhibitor, but its stability in a high chloride ion environment is insufficient;

[0006] German patent DE20230567890A1 studies organic-inorganic composite corrosion inhibitors, which have relatively complex molecular designs and high preparation costs. Summary of the Invention

[0007] (1) Technical problems solved

[0008] In view of the deficiencies of the prior art, the present invention provides a preparation and application of a sewage corrosion inhibitor.

[0009] (2) Technical solution

[0010] To achieve the above object, the present invention provides the following technical solution: a method for preparing a sewage corrosion inhibitor, comprising the following steps:

[0011] Step 1, preparing a phosphate corrosion inhibitor by reacting triethanolamine with phosphoric acid;

[0012] Step 2, forming PEO-PPO-PEO by block copolymerization of ethylene oxide and propylene oxide;

[0013] Step 3, modifying ZnO or ZrSiO4 nanoparticles by a silane coupling agent;

[0014] Step 4: Mix the above components with the bio-based solvent and stir evenly to obtain a corrosion inhibitor.

[0015] Preferably, in step 2, the molar ratio of EO to PO in the block copolymer is 2:1.

[0016] Preferably, in step 3, the particle size of the inorganic nanoparticles is 10-50 nm, and the modifier is KH550 silane coupling agent.

[0017] The invention discloses an application of a sewage corrosion inhibitor, wherein the corrosion inhibition efficiency of the corrosion inhibitor is ≥95%, the applicable pH value range is 4-10, and the biodegradation rate is ≥90%.

[0018] (3) Beneficial effects

[0019] The present invention provides a method for preparing a high-mineralization sewage corrosion inhibitor, which has the following advantages:

[0020] High efficiency: Corrosion inhibition efficiency ≥95%, suitable for environments with high concentrations of salt, chloride ions and sulfate ions.

[0021] Multifunctionality: It has the triple functions of corrosion inhibition, scale inhibition and dispersion.

[0022] Environmental protection: Use of bio-based solvents and low-toxic raw materials is more environmentally friendly. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] A method for preparing a sewage corrosion inhibitor comprises the following steps:

[0025] Step 1, preparing a phosphate corrosion inhibitor by reacting triethanolamine with phosphoric acid;

[0026] Step 2, forming PEO-PPO-PEO by block copolymerization of ethylene oxide and propylene oxide;

[0027] Step 3, modifying ZnO or ZrSiO4 nanoparticles by a silane coupling agent;

[0028] Step 4: Mix the above components with the bio-based solvent and stir evenly to obtain a corrosion inhibitor.

[0029] Preferably, in step 2, the molar ratio of EO to PO in the block copolymer is 2:1.

[0030] Preferably, in step 3, the particle size of the inorganic nanoparticles is 10-50 nm, and the modifier is KH550 silane coupling agent.

[0031] Specifically:

[0032] 1. Chemical composition and mechanism of action

[0033] 1.1 Phosphate corrosion inhibition components:

[0034] Chemical description: Phosphate corrosion inhibitor (such as triethanolamine phosphate), chemical formula is (HOCH2CH2)3N.

[0035] Mechanism of action:

[0036] The phosphoric acid groups in phosphate esters form a dense protective film on the metal surface, inhibiting oxidation and corrosion;

[0037] The triethanolamine group enhances the water solubility of the molecule and improves the dispersion effect of the solution.

[0038] 1.2 Polyethylene oxide block copolymer (PEO-PPO-PEO):

[0039] Chemical description: Polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) triblock copolymer;

[0040] The chemical formula is HO-(CH2CH2O)_n-(CH2CH(CH3)O)_m-(CH2CH2O)_n-H, where n and m are the degree of polymerization.

[0041] Mechanism of action:

[0042] The hydrophobic segment (PPO) combines with the organic dirt on the metal surface to enhance the dispersion ability; the hydrophilic segment (PEO) reduces the direct attack of ionic corrosion on the metal surface through hydration.

[0043] 1.3 Inorganic nanoparticles:

[0044] Chemical description: Zinc oxide (ZnO) or zirconium silicate (ZrSiO4) nanoparticles with a controlled particle size of 10–50 nm and surface modified by silanization.

[0045] Mechanism of action:

[0046] Nanoparticles form a physical barrier on the metal surface, preventing the corrosive medium from coming into contact;

[0047] Silane modification enhances the dispersion stability of particles.

[0048] 2. Preparation Method

[0049] 2.1 Preparation of phosphate corrosion inhibitors:

[0050] (1) Triethanolamine and phosphoric acid (mass ratio 3:1) were mixed at 100°C;

[0051] (2) reacting for 6 hours under the action of an acid catalyst (such as ammonium dihydrogen phosphate) to produce triethanolamine phosphate;

[0052] (3) The reaction product is vacuum distilled to remove water to obtain a high-purity phosphate corrosion inhibitor.

[0053] 2.2 Synthesis of polyethylene oxide block copolymers:

[0054] (1) In a jacketed reactor, ethylene oxide (EO) and propylene oxide (PO) are reacted in a

[0055] Add in a 2:1 ratio;

[0056] (2) Add double metal cyanide catalyst (such as Zn3[Co(CN)6]2) to react

[0057] Temperature 80℃;

[0058] (3) The reaction time is 4–6 hours to generate PEO-PPO-PEO block copolymer.

[0059] Purified by ethanol precipitation.

[0060] 2.3 Modification of inorganic nanoparticles:

[0061] (1) ZnO or ZrSiO4 nanoparticles and silane coupling agent (such as KH550) are mixed in an acetylene

[0062] Mixed in alcohol;

[0063] (2) Disperse under ultrasonic conditions for 30 minutes, and then reflux at 120°C for 2 hours;

[0064] (3) The modified particles are centrifuged and dried to obtain highly dispersible nanoparticles.

[0065] 2.4 Preparation of final corrosion inhibitor:

[0066] (1) Mix the above three components in a mass ratio of 4:3:2;

[0067] (2) Add bio-based solvents (such as glycerol) to adjust the concentration to 10%–20%;

[0068] (3) Mixing under high-speed stirring for 30 minutes, and filtering to obtain the finished product.

[0069] Example 1:

[0070] 1. Preparation of phosphate corrosion inhibitors:

[0071] ① Add 600kg of triethanolamine and 8kg of ammonium dihydrogen phosphate to a dry and clean reactor, heat it to 90℃, and stir.

[0072] ②Control the temperature at 90-100℃ and slowly add 200kg of phosphoric acid dropwise. Control the temperature at 90-100℃ during the addition process.

[0073] ③ After the dropwise addition is completed, the temperature is controlled at 100-110°C and the reaction is kept warm for 6 hours to obtain a phosphate corrosion inhibitor.

[0074] 2. Block copolymer synthesis:

[0075] ①Control the temperature at 0-10℃, add 600kg of ethylene oxide and 300kg of propylene oxide into the dry and clean reactor, and stir for 30 minutes.

[0076] ② Add 1 kg of double metal cyanide catalyst (such as Zn3[Co(CN)6]2), stir for 15 minutes, then slowly heat to 80°C, control the reaction temperature at 80-100°C and the pressure at 0.75-0.9 MPa, and keep the reaction warm for 6 hours to obtain a block copolymer.

[0077] 3. Synthesis of modified inorganic nanoparticles:

[0078] ① Add 100kg of ZrSiO4 nanoparticles, 5kg of silane coupling agent KH550, and 700kg of anhydrous ethanol into a dry and clean ultrasonic dispersion tank according to the amount specified in the process sheet, control the temperature to <40℃, and stir for 2h.

[0079] ② Set the ultrasonic frequency to 30 kHz, the stirring time to 30 minutes, and the reflux temperature to 120°C. Under these production conditions, keep reflux for 2 hours.

[0080] ③ Use a centrifuge to separate and dry the modified ions to obtain modified inorganic nanoparticles 4. Preparation of corrosion inhibitor:

[0081] ① Add 200 kg of phosphate corrosion inhibitor, 150 kg of block copolymer, and 100 kg of modified inorganic nanoparticles into a dry and clean reactor and stir for 30 minutes.

[0082] ② Continue to add 500kg of propylene glycol and 1500kg of pure water, and stir for 30 minutes until the state is uniform.

[0083] ③ Filter, discharge and measure to obtain high-mineralization sewage corrosion inhibitor.

[0084] 3. Performance testing and industrial applications

[0085] 3.1 Performance test:

[0086] Corrosion inhibition efficiency: In high-mineralization wastewater with a salt content of 10%, the corrosion inhibition rate is ≥95%; (High-mineralization brine preparation: 8% sodium chloride, 1% calcium chloride, 1% magnesium chloride, and the balance is water.)

[0087] Stability: The performance of the corrosion inhibitor does not change significantly in the pH range of 4-10; (the pH value of the highly mineralized brine is adjusted by acetic acid)

[0088] Environmental protection: Biodegradation rate ≥ 90%, compliant with REACH and RoHS standards.

[0089] 3.2 Application scenarios:

[0090] Oilfield water injection system: effectively inhibit pipeline corrosion in the reinjection water system and extend the service life of equipment;

[0091] High-salt wastewater treatment: Prevent equipment corrosion in high-salt wastewater in refineries;

[0092] Industrial cooling water: used for corrosion inhibition treatment of highly mineralized industrial cooling water to reduce corrosion deposition.

[0093] The invention discloses an application of a sewage corrosion inhibitor, wherein the corrosion inhibition efficiency of the corrosion inhibitor is ≥95%, the applicable pH value range is 4-10, and the biodegradation rate is ≥90%.

[0094] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0095] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0096] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing a sewage corrosion inhibitor, characterized in that: The steps include: Step 1, preparing a phosphate corrosion inhibitor by reacting triethanolamine with phosphoric acid; Step 2, forming PEO-PPO-PEO by block copolymerization of ethylene oxide and propylene oxide; Step 3, modifying ZnO or ZrSiO4 nanoparticles by a silane coupling agent; Step 4: Mix the above components with the bio-based solvent and stir evenly to obtain a corrosion inhibitor.

2. The method for preparing a sewage corrosion inhibitor according to claim 1, wherein In the step 2, the molar ratio of EO to PO in the block copolymer is 2:

1.

3. The method for preparing a sewage corrosion inhibitor according to claim 2, wherein: In the step 3, the particle size of the inorganic nanoparticles is 10-50 nm, and the modifier is KH550 silane coupling agent.

4. The method for preparing a sewage corrosion inhibitor according to claim 3, wherein: The detailed steps of step 1 are: Step a1: add 600 kg of triethanolamine and 8 kg of ammonium dihydrogen phosphate to a dry and clean reactor, heat to 90°C, and stir; Step a2, slowly adding 200 kg of phosphoric acid at a temperature of 90-100° C., and controlling the temperature at 90-100° C. during the addition; After the step a3, the dropwise addition is completed, the temperature is controlled at 100-110° C., and the reaction is kept warm for 6 hours to obtain a phosphate corrosion inhibitor.

5. The method for preparing a sewage corrosion inhibitor according to claim 4, wherein: The detailed steps of step 2 are: Step b1, in a jacketed reactor, adding ethylene oxide (EO) and propylene oxide (PO) in a ratio of 2:1; Step b2: adding a double metal cyanide catalyst (such as Zn3[Co(CN)6]2) at a reaction temperature of 80°C; Step b3: reaction time 4-6 hours to generate PEO-PPO-PEO block copolymer, which is purified by ethanol precipitation.

6. The method for preparing a sewage corrosion inhibitor according to claim 5, characterized in that: The detailed steps of step 3 are: Step c1: Add 100 kg of ZrSiO4 nanoparticles, 5 kg of silane coupling agent KH550, and 700 kg of anhydrous ethanol to a dry and clean ultrasonic dispersion tank according to the amount specified in the process sheet, control the temperature to less than 40°C, and stir for 2 hours; Step c2: setting the ultrasonic frequency to 30 kHz, the stirring time to 30 minutes, and the reflux temperature to 120° C., and keeping the temperature under reflux for 2 hours under these production conditions; Step c3: centrifugally separating and drying the modified ions using a centrifuge to obtain modified inorganic nanoparticles.

7. The method for preparing a sewage corrosion inhibitor according to claim 6, characterized in that: The detailed steps of step 4 are: Step d1: add 200 kg of phosphate corrosion inhibitor, 150 kg of block copolymer, and 100 kg of modified inorganic nanoparticles to a dry and clean reactor and stir for 30 minutes; Step d2: Continue to add 500 kg of glycerol and 1500 kg of pure water, and stir for 30 minutes until the mixture is uniform; Step d3, filtering, discharging and metering to obtain the high-mineralization sewage corrosion inhibitor.

8. An application of a sewage corrosion inhibitor, characterized in that: The corrosion inhibition efficiency of the corrosion inhibitor is ≥95%, the applicable pH value range is 4-10, and the biodegradation rate is ≥90%.