CN1521236A - Method for removing metals in hydrocarbon oil with copolymer containing acrylic acid and sulfonic acid or its salt - Google Patents

Abstract

A method for removing metals from hydrocarbon oil with a copolymer containing acrylic acid and 2-acrylamide-2-methylpropylsulfonic acid, including: copolymerizing acrylic acid and 2-acrylamide-2-methylpropylsulfonic acid Compounds or their salts are fully mixed with water injection and demulsifier at 30-200°C, so that the metals in the hydrocarbon oil form water-soluble complexes, dissolve in water, and remove the metals in the hydrocarbon oil through oil-water separation. The method of the invention has the characteristics of small dosage and high removal efficiency, and can be applied to any hydrocarbon oil containing super-allowable amount of calcium.

Description

Method for removing metals in hydrocarbon oil with copolymer containing acrylic acid and sulfonic acid or its salt

technical field

The invention relates to a method for removing metals in hydrocarbon oil by using a copolymer containing acrylic acid and 2-acrylamide-2-methylpropylsulfonic acid or its salt.

technical background

In recent years, with the development of oil extraction technology, many heavy crude oils have been extracted. The content of metals in these crude oils, especially some alkaline earth metals such as Ca, Mg, and Fe, has greatly increased, and their influence on crude oil processing has been paid more and more attention by people. Studies have shown that the increase of Ca content in raw oil will significantly reduce the molecular sieve and matrix area of the catalyst, which will directly affect the activity of the catalyst. In recent years, some refineries refining high-Ca crude oil have been poisoned and deactivated by catalytic cracking agents, which not only greatly reduces the yield of light oil, but also affects the quality of downstream residual oil, resulting in a significant reduction in the refinery's crude oil processing profits .

Some of the alkaline earth metals Ca and Mg in crude oil exist in the form of water-soluble salts and slightly soluble salts such as calcium chloride, calcium bicarbonate, calcium sulfate, calcium carbonate, etc., and most of them exist in the form of oil-soluble calcium petroleum acid. In the process of electric desalination in general refineries, most of the soluble salts are mainly removed, and there is almost no removal effect on various water-insoluble inorganic metal salts and organic bound calcium petroleum. Most of these metals remain in the atmospheric or vacuum residue, which affects the further processing and utilization of the vacuum residue.

A lot of research work has been carried out at home and abroad on the demetallization technology of crude oil. In the early U.S. Patent No. 3,059,368, H.Bieber disclosed a method of treating hydrocarbon oil with inorganic acids such as hydrochloric acid to condense Ni, V, Fe and other porphyrin metal compounds in the oil, and then separate the condensates to achieve removal. method for metal purposes. At present, the demetallization agents disclosed in domestic and foreign literature and widely used in industry can be roughly divided into three categories according to their action mechanism: (1) Precipitating agent, mainly can generate hydrophilic slightly soluble or difficult to dissolve with calcium in oil Phosphoric acid, sulfuric acid or their salts of soluble salts, such as CN1054261 uses ammonium phosphate as a precipitant, sulfate, hydrohydroxyphenol as a solid wetting agent; CN1055552 uses H ₂ SO ₄ or its salts as a metal removal agent, and organic phosphine Acid or its salt is used as precipitation inhibitor; CN1232487 adopts CO ₂ to carry out decalcification. Since the generated calcium carbonate, calcium sulfate or calcium phosphate is slightly soluble or insoluble in water, and is easily entrained by the oil phase, the decalcification effect of this type of demetallization agent is affected. (2) Inorganic chelating agents, mainly polyphosphoric acid or its salts that can generate water-soluble chelates with Ca, such as CN1076473 report with sodium hexametaphosphate or sodium tripolyphosphate as chelating agent. Since polyphosphoric acid or its salts are chemically easy to hydrolyze to produce orthophosphoric acid or its salts, and the dosage is relatively large, calcium cannot be effectively removed.

(3) Organic chelating agents, mainly aminocarboxylic acids or their salts, dicarboxylic acids or their salts, monocarboxylic acids or their salts, hydroxycarboxylic acids or their salts, which can form water-soluble chelates with Ca Classes, organic phosphonic acid or its salts, organic sulfonic acid or its salts, organic phosphonic sulfonic acid compounds, such as CN8,610,728A, CN1,036,981, US4,988,433, CN87,105,863 A, CN1,120,575, CN1,221,018 , CN1221018 and other reported metal removal agents belong to this category. In U.S. Patent No. 4,439,345, Duke discloses a method of using carboxylic acid or its amine salt to demetallate from the mesophase emulsion of surfactant enhanced oil displacement product to make it break. In U.S. Patent No. 5,976,358, Sartori et al. used crude oil to contact with resins carrying carboxyl, sulfonic acid and phosphonic acid groups to remove metal calcium from petroleum.

Contents of the invention

The present invention adopts the copolymer containing acrylic acid and 2-acrylamide-2-methylpropyl sulfonic acid or its salt to remove metals in hydrocarbon oils, and alleviates the influence of alkaline earth metals and transition metals, especially Ca and Fe, on the deep processing of hydrocarbon oils , to meet the requirements of subsequent processing.

The method for removing metals in hydrocarbon oils provided by the invention comprises: fully mixing the copolymer containing acrylic acid and 2-acrylamide-2-methylpropyl sulfonic acid or its salt with water injection and demulsifier to make the metals in hydrocarbon oils Metals form water-soluble complexes, dissolve in water, and remove metals from hydrocarbon oil through oil-water separation.

Said copolymer containing acrylic acid and sulfonic acid can also contain maleic acid (anhydride) (MA ), styrenesulfonic acid (SS), acrylamide (AM), hydroxypropyl acrylate (HPA) and 2-acrylamide-2-methylpropylphosphonic acid (AMPP) and other monomers to form structure, composition, molecular weight Different binary or more than binary copolymers, such as acrylic acid-2-acrylamide-2-methylpropylsulfonic acid copolymer (AA/AMPS), such as acrylic acid-acrylamide-2-acrylamide-2-methyl Alkylpropylsulfonic acid copolymer (AA/AM/AMPS), acrylic acid-2-acrylamide-2-methylpropylsulfonic acid-2-acrylamide-2-methylpropylphosphonic acid copolymer (AA/AMPS /AMPP), acrylic acid-2-acrylamide-2-methylpropylsulfonic acid-styrenesulfonic acid copolymer (AA/AMPS/SS), etc.

Studies have shown that the non-porphyrin form of oil-soluble calcium and iron in crude oil mainly exists in the form of naphthenate. By fully mixing the copolymer containing acrylic acid and AMPS sulfonic acid and water with crude oil, the copolymer combines with metal ions such as calcium, magnesium and iron in crude oil in the form of naphthenate at the oil-water interface to form a water-soluble The complex and enter the water phase to separate the oil and water, thereby removing the metals in the crude oil.

In said copolymer containing acrylic acid and sulfonic acid, the content of acrylic acid is 10-95%, preferably 30-70%, and the content of 2-acrylamide-2-methylpropylsulfonic acid is 5-80%, preferably 20% -50%, and the content of the remaining comonomers is 0-20%. The molecular weight of the copolymer is 500-30000, preferably 1000-20000; the amount of the copolymer is 0.5-5 times, preferably 1.0-3.5 times, the total mass of calcium in the hydrocarbon oil.

The salt of said copolymer is a water-soluble salt, such as potassium salt, sodium salt, ammonium salt and the like.

The hydrocarbon oil may be crude oil, heavy hydrocarbon residue, solvent deasphalted oil, or other hydrocarbon oil derived from crude oil.

In actual operation, the copolymer can be added to water injection first, and then mixed with hydrocarbon oil, or directly added to hydrocarbon oil, but it is best to mix with water injection first, and the total water injection volume is 3-50% of the volume of hydrocarbon oil, preferably 4-20%. It can be adjusted to pH 2-7 with ammonia water according to the situation, preferably 4-7. The oil-water mixing time is generally 0.5 seconds to 60 minutes. Generally speaking, the mixing method and mixing intensity are different, and the time to achieve full mixing is also different. For example, the fruit juice mixer sold on the market can be mixed within 1 second to 2 minutes. uniform. The mixing temperature varies with the density and viscosity of the hydrocarbon oil feedstock. The higher the density, the higher the viscosity, the higher the required mixing temperature. Otherwise, it can be carried out at room temperature, generally 30-200°C, preferably 60- 150°C.

The demulsifier can be selected according to the type of crude oil or hydrocarbon raw material, and can be purchased as a supporting product from a manufacturer that sells hydrocarbon oil. It can be a single demulsifier or a composite demulsifier, such as BP2040, FC9301 or NS9906, etc., and the dosage is 1-100ppm of the hydrocarbon oil weight. The function of the demulsifier is to promote oil-water separation.

The method of the invention can be carried out in the conventional desalination process of the oil refinery, and can be realized on the electric desalination device in actual operation, so that the decalcification, desalination and dehydration processes can be completed together. Oil-water separation can be done by any technique including counter-current extraction methods. When implemented on the electric desalination device, in order to reduce or avoid the corrosion of acid on the relevant carbon steel equipment, the electric desalination device, including the injection pipeline, the electric desalination tank and the internal electrode plate, etc. should be anti-corrosion treated before implementation.

The method of the invention has the characteristics of small dosage and high removal efficiency, and can be applied to any hydrocarbon oil containing super-allowable amount of calcium.

Detailed ways

Example 1

The raw material oil used in the experiment came from a petrochemical refinery in Northwest China, which was the vacuum residue after mixing the Xinjiang North Xinjiang crude oil and the South Xinjiang crude oil at a ratio of 7:3. Dilute the residual oil with kerosene in the laboratory, the ratio of residual oil to kerosene is 4:1, the calcium content of the raw oil after dilution is 85.3ppm, and the iron content is 9.9ppm. Prepare raw material oil and preheat to 90-100°C. AA/AMPS copolymer (molecular weight 1000-20000, containing about 20-50% of AMPS, provided by Beijing Linhua Water Quality Stabilizer Factory), water injection, and demulsifier are formulated into an aqueous solution according to a certain agent/calcium mass ratio and a water injection rate of 10%. The demulsifier is NS-9906, and the dosage is 50ppm. Fully mix the prepared aqueous solution and preheated raw material oil in a stirrer, then pour it into a conical glass desalination tank, and use a DP-II electric desalination and demulsification device to separate oil and water, with an electric field gradient of 200v/cm and a temperature of 80°C for one hour After extraction, the crude oil was sampled and analyzed for calcium and iron content by plasma emission spectrometry (ICP/AES). The results are shown in Table 1 below.

Table 1 Dose/Calcium Mass Ratio Metal content of crude oil after stripping/ppm Metal removal rate/% Ca Fe Ca Fe 1.76 20.7 5.8 75.7 41.1 2.64 10.7 5.4 87.4 45.4

From the results in Table 1, it can be seen that the vacuum residue of crude oil mixed with crude oil in Beijiang and Nanjiang at a ratio of 3:7 not only has a good decalcification effect in the optimal range of agent/calcium mass ratio of 1.0-4.0, but also has a good decalcification effect on iron Has a removal effect.

Example 2

In this embodiment, AA/AMPS copolymer (molecular weight 1000-20000, AMPS 20-50%, provided by Beijing Linhua Water Quality Stabilizer Factory) is used to remove calcium and iron in the heavy oil in the ninth district of Karamay. The crude oil used in the experiment is heavy oil from the ninth district of Karamay, Xinjiang and its mixed oil with kerosene at a ratio of 7:3. The experimental demulsifier is FC9301, and the experimental procedure is the same as in Example 1. The results are shown in Table 2 below.

Example 3

This example uses a terpolymer containing acrylic acid and AMPS for demetallation.

The crude oil used in the experiment was heavy oil from the ninth district of Karamay, Xinjiang. Demetallization agent acrylic acid/2-acrylamide-2-methylpropanesulfonic acid/2-acrylamide-2-methylpropylphosphonic acid (AA/AMPS/AMPP) copolymer (provided by Nanjing University Water Quality Stabilizer Factory), Demetallization agent acrylic acid/2-acrylamido-2-methylpropanesulfonic acid/hydroxypropyl acrylate (AA/AMPS/HPA copolymer (U.S. Nacol company product NC-309). Experimental procedure is the same as embodiment 1. Result As shown in Table 3 below.

Table 2 Crude oil origin and crude oil type Dose/Calcium Mass Ratio Metal content of crude oil after stripping/ppm Metal removal rate/% Ca Fe Ca Fe Xinjiang Karamay 9 heavy oil (266ppm calcium, 24.6 iron) 0 254 - 4.4 0.85 152 24.3 42.0 1.2 1.13 101 23.2 61.5 5.7 1.41 63.8 22.5 75.6 8.5 1.69 28.1 22.2 89.4 9.8 1.80 13.3 18.4 95.0 25.2 The 7:3 mixture of heavy oil and kerosene in Karamay District 9 (calcium 190.5ppm, iron 18.1ppm) 0.79 65.3 17.9 66.0 1.1 1.18 5.0 17.2 97.4 5.3 1.78 5.4 7.0 97.2 61.4 1.97 5.9 3.4 96.9 81.5

As can be seen from the results in Table 2, the decalcification rate is only 4.4% without decalcification agent. For the heavy oil in the 9th district of Karamay, Xinjiang and its mixed oil with kerosene, the calcium and iron content can be removed when the agent/calcium molar ratio is as low as 2.

table 3 Type of demetallizer Dose/Calcium Mass Ratio Metal content of crude oil after stripping/ppm Metal removal rate/% Ca Fe Ca Fe AA/AMPS/AMPP 1.25 38.8 22.4 85.4 8.8 1.75 21.3 19.6 92.0 20.2 AA/AMPS/HPA 1.75 25.0 20.8 90.6 15.5

From the results in Table 3, it can be seen that the above two copolymers containing acrylic acid and AMPS have good demetallization effects under the condition of low Ca/Ca ratio.

Claims (10)

1. The method for removing metals in hydrocarbon oils with a copolymer containing acrylic acid and 2-acrylamide-2-methylpropylsulfonic acid, comprising: containing acrylic acid and 2-acrylamide-2-methylpropylsulfonic acid The copolymer or its salt is fully mixed with water injection and demulsifier at 30-200 ° C, so that the metal in the hydrocarbon oil forms a water-soluble complex, dissolves in water, and removes the metal in the hydrocarbon oil through oil-water separation. 2. according to the described method of claim 1, it is characterized in that, in said copolymer, also contain and be selected from maleic acid or maleic anhydride, styrene sulfonic acid, acrylamide, hydroxypropyl acrylate and 2-acrylamide- Monomer of 2-methylpropylphosphonic acid. 3. according to the described method of claim 1 or 2, it is characterized in that, said copolymer is selected from acrylic acid-2-acrylamide-2-methyl propyl sulfonic acid copolymer, acrylic acid-acrylamide-2-acrylamide -2-methylpropylsulfonic acid copolymer, acrylic acid-2-acrylamide-2-methylpropylsulfonic acid-2-acrylamide-2-methylpropylphosphonic acid copolymer and acrylic acid-2-acrylamide - 2-Methylpropylsulfonic acid-styrenesulfonic acid copolymer. 4. according to the described method of claim 1, it is characterized in that, in said copolymer, the content of acrylic acid is 10-95%, and the content of 2-acrylamide-2-methyl propylsulfonic acid is 5-80% , the content of the remaining comonomers is 0-20%. 5. according to the described method of claim 1 or 4, it is characterized in that, in said copolymer, the content of acrylic acid is 30-70%, and the content of 2-acrylamide-2-methyl propyl sulfonic acid is 20- 50%. 6. The method according to claim 1, wherein the molecular weight of said copolymer is 500-30000. 7. The method according to claim 1 or 6, characterized in that the molecular weight of said copolymer is 1000-20000. 8. according to the described method of claim 1, it is characterized in that, the consumption of said copolymer is 0.5-5 times of the calcium total mass in hydrocarbon oil. 9. according to the described method of claim 1 or 8, it is characterized in that, the consumption of copolymer is 1.0-3.5 times of the total mass of calcium in hydrocarbon oil. 10. The method according to claim 1, characterized in that the total water injection volume is 3-50% of the hydrocarbon oil volume, and the mixing temperature is 60-150°C.