High-efficiency and environment-friendly scale inhibitor for gasoline stripping tower of ethylene plant and preparation method thereof

Abstract

The application relates to a scale inhibitor and a preparation method thereof, in particular to a high-efficiency environment-friendly scale inhibitor for an ethylene device gasoline stripping tower and a preparation method thereof, which comprises the following components in mass parts: an antioxidant 2-15, an aromatic amine polymerization inhibitor 2-15, a hydroxylamine polymerization inhibitor 4-16, a metal passivator 10-20, a dispersant 10-40 and a solvent 20-50. The scale inhibitor can greatly improve the polymerization inhibition performance, further improve the scale inhibition performance of the scale inhibitor, and ensure good operation of the ethylene device gasoline stripping tower.

Description

Technical Field

[0001] This invention relates to a scale inhibitor and its preparation method, specifically a high-efficiency and environmentally friendly scale inhibitor for gasoline stripping towers in ethylene plants and its preparation method. Background Technology

[0002] The gasoline stripping tower in an ethylene plant is used to strip light hydrocarbon components from cracked gasoline and compressor condensate. The performance of the gasoline stripping tower directly affects the load of the entire ethylene plant. Because the feed contains a significant amount of unsaturated compounds such as styrene, dienes, cycloolefins, and indene, scaling easily occurs on the trays and reboiler under high temperatures. This scaling affects the stable operation of the gasoline stripping tower, and consequently, the normal operation of the gasoline hydrogenation unit.

[0003] Various solutions have been proposed both domestically and internationally to address the aforementioned problems. The most common solution is to add scale inhibitors. For example, patent CN101700991A discloses a high-efficiency scale inhibitor for a styrene plant exhaust compressor, composed of components A, B, and C, characterized by a mass ratio of 1-8:1-8:1-8 for components A, B, and C; wherein component A is a hydroxylamine compound; component B is an alkanolamine compound; and component C is a phenolic compound. However, current scale inhibitors often suffer from poor performance or instability, and their compatibility with gasoline stripping tower systems is also inadequate. Further research and development of more effective scale inhibitors is needed. Summary of the Invention

[0004] To address the above problems, this invention provides a highly efficient and environmentally friendly scale inhibitor for gasoline stripping towers in ethylene plants, comprising the following components (parts by weight):

[0005]

[0006] Preferably, the scale inhibitor comprises the following components (parts by weight):

[0007]

[0008]

[0009] The antioxidants include one or more of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, and o-tert-butylphenol; preferably one or more of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-4-isobutylphenol, and o-tert-butylphenol.

[0010] The aromatic amine polymerization inhibitor is selected from one or more of p-toluidine, benzidine, p-phenylenediamine, diphenylamine, and thioide diphenylamine, preferably one or more of diphenylamine, benzidine, and thioide diphenylamine.

[0011] The hydroxylamine polymerization inhibitor is selected from one or more of ethyl hydroxylamine, diethyl hydroxylamine, isopropyl hydroxylamine, diisopropyl hydroxylamine, dihydroxypropyl hydroxylamine, and 2,2,6,6-tetramethyl-4-hydroxypiperidine hydroxylamine, preferably one or more of diethyl hydroxylamine, diisopropyl hydroxylamine, and 2,2,6,6-tetramethyl-4-hydroxypiperidine hydroxylamine.

[0012] The metal passivating agent is selected from ammonium benzenesulfonate passivating agents, preferably one or two of p-tert-butylbenzenesulfonate ammonium salt and dodecylbenzenesulfonate ammonium salt.

[0013] The dispersant is selected from one or more of polyacrylic acid, acrylic acid copolymer, polymaleic acid, and maleic acid copolymer; preferably, one or more of polyacrylic acid with a number average molecular weight of 2000-4000, acrylic acid copolymer with a number average molecular weight of 1000-3000, polymaleic acid with a number average molecular weight of 1000-4000, and maleic acid copolymer with a number average molecular weight of 1000-4000; more preferably, one or two of polyacrylic acid with a number average molecular weight of 2500-3500 and polymaleic acid with a number average molecular weight of 2000-3000.

[0014] The solvent is selected from hydrocarbon solvents, preferably one or more of hexane, cyclohexane, kerosene, diesel, raffinate oil and 200# solvent oil; more preferably one or more of cyclohexane, kerosene and 200# solvent oil.

[0015] This invention identifies a suitable weight ratio of antioxidants, compound polymerization inhibitors, and metal passivators for gasoline stripping towers in ethylene plants. This synergistic effect among the three substances results in a stronger scale inhibition effect on the gasoline stripping tower. The invention also involves formula screening, demonstrating that using a combination of multiple polymerization inhibitors achieves superior results. Aromatic amine polymerization inhibitors are commonly used molecular-type inhibitors that can consume trace amounts of oxygen in the system and also have antioxidant effects. Hydroxylamine polymerization inhibitors can inhibit polymerization reactions and, in the process, can react with peroxide free radicals. Hydroxylamine can also inhibit polymerization by generating nitroxide free radicals and undergoing chain termination reactions with chain free radicals. This invention uses a combination of both, along with phenolic antioxidants, to significantly improve polymerization inhibition performance, thereby enhancing the scale inhibition performance of the scale inhibitor.

[0016] Furthermore, this invention uses ammonium benzenesulfonate as a metal passivating agent, replacing the use of common (phosphite) ester passivating agents, thus avoiding phosphorus pollution to the environment. Therefore, the gasoline stripping tower scale inhibitor of this invention is more environmentally friendly in actual use.

[0017] This invention also provides a method for preparing a highly efficient and environmentally friendly scale inhibitor for gasoline stripping towers in ethylene plants, the preparation method comprising the following steps:

[0018] Simply mix all the components thoroughly according to the formula.

[0019] Preferably, the antioxidant, polymerization inhibitor, metal passivator, dispersant and solvent are first mixed and heated to dissolve.

[0020] Preferably, the dissolved scale inhibitor is cooled to room temperature and then filtered.

[0021] The present invention also provides an application of a high-efficiency and environmentally friendly scale inhibitor for gasoline stripping towers in ethylene plants. The scale inhibitor is used in gasoline stripping towers in ethylene plants to improve scaling in gasoline stripping towers and extend the operating cycle of the equipment.

[0022] Based on the gasoline stripping tower material, the amount of scale inhibitor added is 1-500 ppm, preferably 10-100 ppm, and more preferably 20-80 ppm.

[0023] In addition, the present invention also provides a method for using a high-efficiency and environmentally friendly scale inhibitor for gasoline stripping towers in ethylene plants, the method comprising the following steps:

[0024] Simply add the scale inhibitor mentioned above to the feed of the gasoline stripping tower.

[0025] Of course, the scale inhibitor can be dissolved in other solvents first, or it can be premixed with a small portion of the feed.

[0026] Compared with existing technologies, the scale inhibitor for gasoline stripping towers in ethylene plants of this invention has the following beneficial effects:

[0027] (1) Through repeated screening of the formulation, the present invention can achieve better results by using a combination of multiple polymerization inhibitors. The present invention uses a combination of aromatic amine polymerization inhibitors and hydroxylamine polymerization inhibitors, combined with the use of phenolic antioxidants, which can greatly improve the polymerization inhibition performance, thereby improving the scale inhibition performance of the scale inhibitor and ensuring the good operation of the gasoline stripping tower of the ethylene unit.

[0028] (2) This scale inhibitor takes into account both high-efficiency scale inhibition and environmental protection performance. It uses ammonium benzenesulfonate salt and does not use phosphates. It is green and environmentally friendly and will not have a negative impact on the water system.

[0029] (3) The present invention uses a simple formula to combine antioxidants, polymerization inhibitors, metal passivators, etc., with a scale inhibition rate of up to about 98%. It is easy to use and can significantly improve the scaling of gasoline stripping towers, extend the operating cycle of equipment, and reduce costs. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0031] This invention provides a highly efficient and environmentally friendly scale inhibitor for gasoline stripping towers in ethylene plants, comprising the following components (parts by weight):

[0032]

[0033] Preferably, the scale inhibitor comprises the following components (parts by weight):

[0034]

[0035] The antioxidants include one or more of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, and o-tert-butylphenol; preferably one or more of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-4-isobutylphenol, and o-tert-butylphenol.

[0036] The aromatic amine polymerization inhibitor is selected from one or more of p-toluidine, benzidine, p-phenylenediamine, diphenylamine, and thioide diphenylamine, preferably one or more of diphenylamine, benzidine, and thioide diphenylamine.

[0037] The hydroxylamine polymerization inhibitor is selected from one or more of ethyl hydroxylamine, diethyl hydroxylamine, isopropyl hydroxylamine, diisopropyl hydroxylamine, dihydroxypropyl hydroxylamine, and 2,2,6,6-tetramethyl-4-hydroxypiperidine hydroxylamine, preferably one or more of diethyl hydroxylamine, diisopropyl hydroxylamine, and 2,2,6,6-tetramethyl-4-hydroxypiperidine hydroxylamine.

[0038] The metal passivating agent is selected from ammonium benzenesulfonate passivating agents, preferably one or two of p-tert-butylbenzenesulfonate ammonium salt and dodecylbenzenesulfonate ammonium salt.

[0039] The dispersant is selected from one or more of polyacrylic acid, acrylic acid copolymer, polymaleic acid, and maleic acid copolymer; preferably, one or more of polyacrylic acid with a number average molecular weight of 2000-4000, acrylic acid copolymer with a number average molecular weight of 1000-3000, polymaleic acid with a number average molecular weight of 1000-4000, and maleic acid copolymer with a number average molecular weight of 1000-4000; more preferably, one or two of polyacrylic acid with a number average molecular weight of 2500-3500 and polymaleic acid with a number average molecular weight of 2000-3000.

[0040] The solvent is selected from hydrocarbon solvents, preferably one or more of hexane, cyclohexane, kerosene, diesel, raffinate oil and 200# solvent oil; more preferably one or more of cyclohexane, kerosene and 200# solvent oil.

[0041] This invention also provides a method for preparing a highly efficient and environmentally friendly scale inhibitor for gasoline stripping towers in ethylene plants, the preparation method comprising the following steps:

[0042] Simply mix all the components thoroughly according to the formula.

[0043] Preferably, the antioxidant, polymerization inhibitor, metal passivator, dispersant and solvent are first mixed and heated to dissolve.

[0044] Preferably, the dissolved scale inhibitor is cooled to room temperature and then filtered.

[0045] The present invention also provides an application of a high-efficiency and environmentally friendly scale inhibitor for gasoline stripping towers in ethylene plants. The scale inhibitor is used in gasoline stripping towers in ethylene plants to improve scaling in gasoline stripping towers and extend the operating cycle of the equipment.

[0046] Based on the gasoline stripping tower material, the amount of scale inhibitor added is 1-500 ppm, preferably 10-100 ppm, and more preferably 20-80 ppm.

[0047] In addition, the present invention also provides a method for using a high-efficiency and environmentally friendly scale inhibitor for gasoline stripping towers in ethylene plants, the method comprising the following steps:

[0048] Simply add the scale inhibitor mentioned above to the feed of the gasoline stripping tower.

[0049] Of course, the scale inhibitor can be dissolved in other solvents first, or it can be premixed with a small portion of the feed.

[0050] Examples 1-14, Comparative Examples 1-5

[0051] The scale inhibitors for gasoline stripping towers in the high-efficiency and environmentally friendly ethylene plants described in Examples 1-14 and Comparative Examples 1-5 are prepared as follows:

[0052] Antioxidant, polymerization inhibitor, stripping agent, dispersant and solvent are mixed and heated to dissolve the solid components. Then, the mixture is cooled to room temperature and filtered to obtain the gasoline stripping tower scale inhibitor. The corresponding formula is shown in Table 1-3.

[0053] Table 1

[0054]

[0055]

[0056] Table 2

[0057]

[0058]

[0059] Table 3

[0060]

[0061]

[0062] Performance testing:

[0063] The scale inhibition performance of the scale inhibitors prepared in Example 1, Example 14 and Comparative Example 1, Example 5 was tested respectively.

[0064] The evaluation method for the scale inhibition performance of scale inhibitors is derived from the principle of heat transfer: In the principle of heat transfer, a heat pipe is used, and the feed flows continuously inside the heat pipe. Initially, since the feed has not yet formed scale on the heat pipe, the total heat transfer resistance is only the heat transfer resistance of the heat pipe wall. As the operating time increases, scale is continuously deposited on the surface of the heat pipe, forming a scale layer, which prevents heat transfer. At this time, the total heat transfer resistance is the sum of the pipe wall thermal resistance and the scale thermal resistance.

[0065] If the feed composition, flow rate, and inlet temperature remain constant, the feed outlet temperature will decrease as scale forms on the inner wall of the heat pipe. Adding a scale inhibitor reduces scale formation, thus minimizing the drop in outlet temperature. Different scale inhibitors have varying scale inhibition effects, resulting in different feed outlet temperatures. Obviously, a better scale inhibitor will produce a higher feed outlet temperature, and vice versa, thus achieving the purpose of evaluating the performance of the scale inhibitor.

[0066] Based on the above principles, this invention evaluates the scale inhibition performance of a prepared scale inhibitor by assessing its scale inhibition rate. The specific testing method involves using a laboratory metering pump to feed the material into a heat pipe, heating the heat pipe with an electric heating wire while controlling the heating temperature to maintain a constant temperature on the outer wall of the heat pipe, and using thermocouples to test the temperatures at the feed inlet and outlet of the heat pipe. The feed material is not reused after flowing out of the heat pipe. The scale inhibition effect of the scale inhibitor is represented by the scale inhibition rate A.

[0067]

[0068] Where T 0t T represents the inlet and outlet temperatures for t hours without the addition of scale inhibitor. t The temperature of the feed outlet after t hours of testing following the addition of scale inhibitor is T. 外 This is the temperature of the outer wall of the heat pipe.

[0069] During the test, the scale inhibitor concentration was 50 ppm, the feed inlet temperature was 60℃, the heat pipe outer wall temperature was 80℃, the feed flow rate was 100 mL / min, and the test time was 24 hours; the test results are shown in Table 4.

[0070] Table 4:

[0071]

[0072]

[0073] As can be seen from the table above, the scale inhibition rates of Examples 1-14 are better than those of Comparative Examples 1-5, indicating that the scale inhibitors in the corresponding formulations can exert a good scale inhibition effect. Comparative Examples 1-2 show that without the addition of aromatic amine polymerization inhibitors or hydroxylamine polymerization inhibitors, the scale inhibition effect is significantly reduced, indicating that the combination of aromatic amine polymerization inhibitors, hydroxylamine polymerization inhibitors, and phenolic antioxidants can achieve a synergistic improvement in scale inhibition.

[0074] As seen in Examples 13-14, the ratio of aromatic amine polymerization inhibitors, hydroxylamine polymerization inhibitors, and phenolic antioxidants in the examples can achieve better scale inhibition effects.

[0075] Furthermore, the scale inhibitor prepared according to the formulation of this invention has been used in the gasoline stripping tower of an ethylene plant, and it can significantly extend the operating cycle of the gasoline stripping tower.

[0076] Of course, those skilled in the art will understand that the embodiments described above are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. The application of a high-efficiency and environmentally friendly scale inhibitor for gasoline stripping towers in ethylene plants, characterized in that the scale inhibitor is used in gasoline stripping towers in ethylene plants. The scale inhibitor has the following composition: 6-10 parts of 2,6-di-tert-butyl-p-cresol; 6-10 parts of thioide diphenylamine; 8-12 parts of 2,2,6,6-tetramethyl-4-hydroxypiperidine hydroxylamine; 12-16 parts of metal passivating agent; 20-30 parts of dispersant; 30-40 parts solvent; The metal passivating agent is selected from one or two of ammonium p-tert-butylbenzenesulfonate and ammonium dodecylbenzenesulfonate.

2. The application of the scale inhibitor according to claim 1, characterized in that the dispersant is selected from one or more of polyacrylic acid, acrylic acid copolymer, polymaleic acid, and maleic acid copolymer.

3. The application of the scale inhibitor according to claim 1, characterized in that the dispersant is selected from one or more of polyacrylic acid with a number average molecular weight of 2000-4000, acrylic acid copolymer with a number average molecular weight of 1000-3000, polymaleic acid with a number average molecular weight of 1000-4000, and maleic acid copolymer with a number average molecular weight of 1000-4000.

4. The application of the scale inhibitor according to claim 1, characterized in that the dispersant is selected from one or two of polyacrylic acid with a number average molecular weight of 2500-3500 and polymaleic acid with a number average molecular weight of 2000-3000.

5. The application of the scale inhibitor according to claim 1, characterized in that the solvent is selected from hydrocarbon solvents.

6. The application of the scale inhibitor according to claim 1, characterized in that the solvent is selected from one or more of hexaane, cyclohexane, kerosene, diesel, raffinate oil and 200# solvent oil.

7. The application of the scale inhibitor according to claim 1, characterized in that the solvent is selected from one or more of cyclohexane, kerosene, and 200# solvent oil.

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