Method and device for cyclically removing metal ions from hydrocarbon oil through electro-desalting

Abstract

The invention relates to the technical field of petroleum processing wastewater treatment, in particular to a method and a device for cyclically removing metal ions in hydrocarbon oil electro-desalting. According to the method, hydrocarbon oil and a decalcifying agent aqueous solution are mixed, then electro-desalting treatment is carried out, and then membrane separation, decalcification treatment, evaporation and condensation are carried out; after decalcification, a decalcification agent concentrated solution, fresh water and condensed water are mixed to obtain a decalcification agent aqueous solution for cyclic utilization; the device comprises a hydrocarbon oil storage tank, a mixer, an electric desalting tank, a microfiltration purification device, a nanofiltration device, a reverse osmosis device, an evaporative condenser, a saline water storage tank, a precipitant storage tank, a curing reaction tank, a first solid-liquid separator, a high-temperature crystallization reaction tank, a second solid-liquid separator and a hydrocarbon oil decalcifying agent aqueous solution tank. On one hand, the treatment capacity of subsequent curing regeneration is reduced, and industrial device miniaturization is achieved; on the other hand, metal ions removed from the hydrocarbon oil are converted into resources, resource utilization of the hydrocarbon oil decalcification wastewater is achieved, and low-carbon emission, environmental protection and circular economy are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum processing wastewater treatment, and is a method and device for hydrocarbon oil electric desalination cycle demetallization. Background Art

[0002] As crude oil resources become heavier, the metal ion content in crude oil is on the rise. At the same time, in order to increase the depth of crude oil processing, more and more heavy oil is used as a raw material for catalytic hydrogenation. However, the presence of high concentrations of metal ions such as calcium and magnesium in heavy oil has largely limited the further improvement of processing depth. In order to solve the hazards of crude oil processing with metal ions and improve the economic benefits of enterprises, the commonly used method is to add chemical agents such as decalcifying agents during the process of electrical desalting and dehydration to achieve the purpose of increasing the removal rate of metal calcium.

[0003] Chinese patent document with publication number CN86107286 discloses a method for decalcifying hydrocarbon raw materials using aminocarboxylic acid and its salts, and removing metal pollutants, especially calcium, from hydrocarbon raw materials. Although this process has the advantages of obvious removal effect and simple operation for demetallization of hydrocarbon oil, the industrial wastewater generated in the demetallization process will have the defect of serious environmental pollution if it is directly discharged. If it is incorporated into the refinery sewage treatment system, it will easily impact the sewage treatment device and even lead to unreasonable drainage.

[0004] The Chinese patent document with the publication number CN1454969A discloses a hydrocarbon oil demetallization circulation method, in which the metal calcium in the hydrocarbon oil is removed by circulation, so that the hydrocarbon oil decalcification agent has the performance of recycling and reduces the consumption cost of the hydrocarbon oil decalcification agent. However, during the recycling process of the hydrocarbon oil decalcification agent, the sodium ions removed from the crude oil are continuously enriched and circulated with the desalted water, resulting in an increase in the conductivity after the electric desalting oil and water are mixed, causing the electric desalting system to trip frequently, affecting the normal operation of the electric desalting device. The solubility of the calcium salt formed after the decalcification agent is regenerated in the desalted water decreases with the increase of temperature. During the recycling process of the hydrocarbon oil decalcification agent, calcium slag deposits are easily formed and deposited in the electric desalting system. In addition, when the calcium ions in the hydrocarbon oil are low, the calcium ion content in the desalted water solution will be low, which has a great influence on crystal nucleation. In the process of industrial implementation, there is often a problem of scaling of pipelines or reactors. This technology has strict control requirements on the amount of precipitant used. If used excessively, the device will be corroded and the water quality of the external drainage will be poor, which will greatly increase the operating pressure of subsequent sewage treatment devices.

[0005] A Chinese patent document with publication number CN105733664A discloses a crude oil electric desalting and decalcification process method, which is to subject organic acid calcium wastewater to a series of treatments. When the calcium ion concentration in the crude oil electric desalting wastewater is greater than 20,000 μg / g, all or part of it is discharged into a water treatment process system, and treated by processes such as acidification, solid-liquid separation, extraction, distillation, and stripping. The treated wastewater is discharged to a sewage treatment plant. However, there is still a problem of scaling of pipelines or reactors in the distillation unit, and the required equipment has a large processing capacity, and the dosage and energy consumption of the decalcifying agent are high, resulting in a great waste of resources and great engineering difficulty.

[0006] A Chinese patent document with publication number CN102399581A discloses a method for recycling a hydrocarbon oil demetallizing agent, in which an ion exchange resin is used instead of a decalcifying agent, and the demetallized resin is treated with an acid and then regenerated. However, there are problems such as a short service life of the resin and difficulty in engineering.

[0007] It can be seen that the introduction of chemical agents has caused a certain degree of change in the water quality of the electro-desalting wastewater produced during the demetallization process. Therefore, the efficient treatment of electro-desalting wastewater has always been a technical bottleneck restricting the industrialization of the decalcification process, and new methods are expected to solve this problem. Summary of the invention

[0008] The present invention provides a method and device for cyclic demetallation of hydrocarbon oil by electric desalination, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the existing problems in the process of hydrocarbon oil decalcification in petroleum processing, such as high cost of hydrocarbon oil decalcification, inability to produce resources, and large pollution emissions resulting in environmental pollution.

[0009] The technical scheme of the present invention is achieved by the following measures: a method for cyclically removing metal ions by electro-desalting hydrocarbon oil, which is carried out according to the following steps: a first step, mixing a required amount of hydrocarbon oil with a decalcifying agent aqueous solution and then subjecting it to electro-desalting treatment to obtain demetallized hydrocarbon oil and a decalcifying agent aqueous solution after reaction; a second step, subjecting the decalcifying agent aqueous solution after reaction to membrane separation to respectively obtain a concentrated solution of a reaction product of calcium ions and the decalcifying agent, a first sodium ion-containing filtrate and fresh water; a third step, subjecting the concentrated solution of the reaction product of calcium ions and the decalcifying agent to decalcification treatment to obtain a decalcified decalcifying agent concentrated solution; a fourth step, evaporating and condensing the first sodium ion-containing filtrate to obtain a second sodium ion-containing filtrate and condensed water; a fifth step, mixing the decalcified decalcifying agent concentrated solution, fresh water and condensed water to obtain a decalcifying agent aqueous solution, which is returned to the first step for recycling.

[0010] The following are further optimizations and / or improvements to the above technical solutions: In the first step, the specific process of the electric desalting treatment is as follows: first, at a temperature of 50°C to 150°C and a pressure of 0.02MPa to 1.0MPa, a required amount of hydrocarbon oil and a decalcifying agent aqueous solution are mixed to obtain a mixed solution; then, the mixed solution is treated for 1min to 60min under an electric field strength of 50V / cm to 500V / cm, and then treated for 5min to 200min under an electric field strength of 500V / cm to 1500V / cm, to obtain demetallized hydrocarbon oil and a reacted decalcifying agent aqueous solution, respectively, wherein the mass content of the decalcifying agent in the mixed solution is 0.01wt% to 5wt%, the mass content of water is 1% to 25%, and the rest is hydrocarbon oil, and the decalcifying agent is one or more of formic acid, acetic acid, propionic acid and butyric acid.

[0011] In the above three steps, the specific process of decalcification treatment is: first, the concentrated solution of the reaction product of calcium ions and the decalcifying agent is mixed with the required amount of precipitant and then subjected to precipitation reaction to obtain a precipitation reaction product; secondly, the precipitation reaction product is subjected to a first solid-liquid separation to obtain a liquid phase product and a solid phase product respectively; then, the solid phase product is washed, separated and dried to obtain a calcium salt product, and the liquid phase product is subjected to a high-temperature crystallization reaction to obtain a high-temperature crystallization reaction product; finally, the high-temperature crystallization reaction product is subjected to a second solid-liquid separation to obtain a decalcified decalcifying agent concentrated solution.

[0012] The above-mentioned precipitant is sulfuric acid or phosphoric acid, the temperature of the precipitation reaction is 20°C to 50°C, the reaction time is 5min to 30min, the temperature of the high-temperature crystallization reaction is 100°C to 150°C, and the reaction time is 5min to 30min.

[0013] In the above second step, the specific process of membrane separation treatment includes: first, passing the decalcifying agent aqueous solution after the reaction through a nanofiltration membrane for at least one stage of nanofiltration treatment to obtain a concentrated solution and a filtrate of the reaction product of calcium ions and the decalcifying agent; then, passing the filtrate through a reverse osmosis membrane for at least one stage of reverse osmosis treatment to obtain a first sodium ion-containing filtrate and fresh water.

[0014] The decalcification agent aqueous solution after the reaction is subjected to two-stage nanofiltration treatment through a nanofiltration membrane, and the filtrate is subjected to one-stage reverse osmosis treatment through a reverse osmosis membrane, wherein the pressure of the nanofiltration treatment is 0.2MPa to 2.0MPa, the nanofiltration membrane is a monovalent ion selective permeable nanofiltration membrane, the material of the nanofiltration membrane is one or more of aromatic polyamide, polypiperazineamide, cellulose acetate and sulfonated polyether sulfone, the pressure of the reverse osmosis treatment is 2.0MPa to 6.0MPa, and the material of the reverse osmosis membrane is one or more of aromatic polyamide, polypiperazineamide, polyimide and sulfonated polysulfone.

[0015] The specific process of the above-mentioned membrane separation treatment also includes: pre-treating the aqueous solution of the decalcifying agent after the reaction, and then performing nanofiltration treatment, wherein the pre-treatment is to perform microfiltration treatment on the aqueous solution of the decalcifying agent after the reaction through a microfiltration membrane, and the material of the microfiltration membrane is one or more of ceramic, polypropylene, polycarbonate, polyvinyl chloride, polysulfone, polyvinylidene fluoride and polytetrafluoroethylene.

[0016] In the fourth step, the evaporation temperature is 120°C to 200°C, the condensation temperature is 20°C to 50°C, and the mass content of the metallic sodium salt in the obtained second sodium ion-containing filtrate is 10% to 30%.

[0017] The second technical solution of the present invention is achieved by the following measures: a device for implementing the method of hydrocarbon oil electric desalting cycle demetallization, comprising a hydrocarbon oil storage tank, a mixer, an electric desalting tank, a microfiltration purification device, a nanofiltration device, a reverse osmosis device, an evaporative condenser, a brine storage tank, a precipitant storage tank, a solidification reaction tank, a first solid-liquid separator, a high-temperature crystallization reaction tank, a second solid-liquid separator, and a hydrocarbon oil decalcification agent aqueous solution tank, wherein a mixed liquid inlet pipeline is fixedly connected between the hydrocarbon oil storage tank outlet and the mixer inlet, a mixed liquid outlet pipeline is fixedly connected between the mixer outlet and the electric desalting tank inlet, a post-reaction decalcification agent aqueous solution inlet pipeline is fixedly connected between the first outlet of the electric desalting tank and the microfiltration purification device inlet, a pre-treated filtrate pipeline is fixedly connected between the microfiltration purification device outlet and the nanofiltration device inlet, a sodium ion filtrate pipeline is fixedly connected between the first outlet of the nanofiltration device and the reverse osmosis device inlet, and a first sodium ion filtrate pipeline is fixedly connected between the first outlet of the reverse osmosis device and the evaporative condenser inlet. A sub-filtrate pipeline, a second sodium ion filtrate pipeline is fixedly connected between the first outlet of the evaporative condenser and the inlet of the brine storage tank, an evaporative condensate delivery pipeline is fixedly connected between the second outlet of the evaporative condenser and the first inlet of the hydrocarbon oil decalcification agent aqueous solution tank, a concentrated liquid delivery pipeline is fixedly connected between the second outlet of the nanofiltration device and the first inlet of the solidification reaction tank, a material liquid delivery pipeline is fixedly connected between the outlet of the solidification reaction tank and the inlet of the first solid-liquid separator, a first concentrated water recovery pipeline is fixedly connected between the first outlet of the first solid-liquid separator and the inlet of the high-temperature crystallization reaction tank, a material delivery pipeline is fixedly connected between the outlet of the high-temperature crystallization reaction tank and the inlet of the second solid-liquid separator, a second concentrated water recovery pipeline is fixedly connected between the first outlet of the second solid-liquid separator and the second inlet of the hydrocarbon oil decalcification agent aqueous solution tank, a recovered solution pipeline is fixedly connected between the outlet of the hydrocarbon oil decalcification agent aqueous solution tank and the mixed liquid inlet pipeline, and a precipitant delivery pipeline is fixedly connected between the outlet of the precipitant storage tank and the second inlet of the solidification reaction tank.

[0018] The following is a further optimization and / or improvement of the second technical solution of the above invention: The above also includes a calcium salt slag tank and a drying device. A first calcium salt pipeline is fixedly connected between the first solid-liquid separator outlet and the first inlet of the calcium salt slag tank, a second calcium salt pipeline is fixedly connected between the second solid-liquid separator outlet and the second inlet of the calcium salt slag tank, a solid phase drying pipeline is fixedly connected between the calcium salt slag tank outlet and the inlet of the drying device, a calcium sulfate product pipeline is fixedly connected to the drying device outlet, a demetallized hydrocarbon oil output pipeline is fixedly connected to the second outlet of the electric desalting tank, a fresh water delivery pipeline is fixedly connected between the second outlet of the reverse osmosis device and the evaporation condensate delivery pipeline, and a water injection pipeline is fixedly connected to the third inlet of the salt slag tank and the third inlet of the hydrocarbon oil decalcification agent aqueous solution tank.

[0019] On the one hand, the present invention reduces the processing volume of subsequent solidification and regeneration, thereby realizing miniaturization of industrial equipment; on the other hand, the metal ions removed from hydrocarbon oil are converted into resources, and hydrocarbon oil decalcification wastewater is utilized as a resource, thereby realizing low-carbon emissions, green environmental protection and circular economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Attached Figure 1 This is a schematic diagram of the process flow of Example 9 of the present invention.

[0021] Attached Figure 1 The codes are as follows: 1 is a hydrocarbon oil storage tank, 2 is a mixer, 3 is an electric desalting tank, 4 is a demetallized hydrocarbon oil output pipeline, 5 is a decalcified aqueous solution inlet pipeline after reaction, 6 is a microfiltration purification device, 7 is a filtrate pipeline after pretreatment, 8 is a nanofiltration device, 9 is a concentrate delivery pipeline, 10 is a sodium ion filtrate pipeline, 11 is a reverse osmosis device, 12 is a fresh water delivery pipeline, 13 is a first sodium ion filtrate pipeline, 14 is an evaporative condenser, 15 is a second sodium ion filtrate pipeline, 16 is an evaporative condensate delivery pipeline, 17 is a brine storage tank, 18 is a precipitant storage tank, 19 is a solidification reaction Tank, 20 is the feed liquid conveying pipeline, 21 is the first solid-liquid separator, 22 is the first concentrated water recovery pipeline, 23 is the calcium salt slag tank, 24 is the drying device, 25 is the calcium sulfate product pipeline, 26 is the high temperature crystallization reaction tank, 27 is the material conveying pipeline, 28 is the second solid-liquid separator, 29 is the second concentrated water recovery pipeline, 30 is the hydrocarbon oil decalcification agent aqueous solution tank, 31 is the recovery solution pipeline, 32 is the water injection pipeline, 33 is the mixed liquid inlet pipeline, 34 is the mixed liquid outlet pipeline, 35 is the precipitant conveying pipeline, 36 is the first calcium salt pipeline, 37 is the second calcium salt pipeline, and 38 is the solid phase drying pipeline. DETAILED DESCRIPTION

[0022] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals known and used in the prior art; the percentages in the present invention are all mass percentages unless otherwise specified; the solutions in the present invention are all aqueous solutions with water as the solvent, for example, hydrochloric acid solution is hydrochloric acid aqueous solution; the normal temperature and room temperature in the present invention generally refer to the temperature of 15°C to 25°C, which is generally defined as 25°C. In the present invention, unless otherwise specified, the equipment and devices used are all equipment and devices known and used in the art.

[0023] The present invention will be further described below in conjunction with embodiments: Embodiment 1: The method for cyclically removing metal ions by electro-desalting hydrocarbon oil is carried out according to the following steps: the first step is to mix the required amount of hydrocarbon oil with a decalcifying agent aqueous solution and then perform electro-desalting treatment to obtain demetallized hydrocarbon oil and a reacted decalcifying agent aqueous solution; the second step is to perform membrane separation on the reacted decalcifying agent aqueous solution to respectively obtain a concentrated solution of the reaction product of calcium ions and the decalcifying agent, a first sodium ion-containing filtrate and fresh water; the third step is to perform decalcification treatment on the concentrated solution of the reaction product of calcium ions and the decalcifying agent to obtain a decalcified decalcifying agent concentrated solution; the fourth step is to evaporate and condense the first sodium ion-containing filtrate to obtain a second sodium ion-containing filtrate and condensed water; the fifth step is to mix the decalcified decalcifying agent concentrated solution, fresh water and condensed water to obtain a decalcifying agent aqueous solution, which is returned to the first step for recycling.

[0024] The invention fully mixes a hydrocarbon oil decalcifying agent aqueous solution with hydrocarbon oil, and then performs an electric desalting process treatment, wherein metal ions in the hydrocarbon oil enter the decalcifying agent aqueous solution, thereby obtaining demetalized hydrocarbon oil (oil phase) and a decalcifying agent aqueous solution after reaction, wherein the decalcifying agent aqueous solution after reaction is an aqueous solution (aqueous phase) containing a compound formed by the reaction of the decalcifying agent and calcium ions and sodium chloride; the decalcifying agent aqueous solution after reaction is subjected to membrane separation treatment to obtain a reaction product concentrate of calcium ions and the decalcifying agent (after membrane separation, the compound formed by the reaction of the decalcifying agent and the calcium ions is retained to form a reaction product concentrate of calcium ions and the decalcifying agent), a first sodium ion-containing filtrate and fresh water without metal salt; the first sodium ion-containing filtrate is further evaporated, concentrated and condensed to obtain a second sodium ion-containing filtrate and evaporated condensed water; the reaction product concentrate of the calcium ions and the decalcifying agent is decalcified, mixed with fresh water without metal salt and evaporated condensed water, and then fully mixed with hydrocarbon oil in a required ratio for recycling, thereby realizing the recycling of the hydrocarbon oil decalcifying agent, the recycling demetallization of hydrocarbon oil and the resource utilization of hydrocarbon oil decalcification wastewater.

[0025] Embodiment 2: As an optimization of the above embodiment, in the first step, the specific process of the electric desalting treatment is: first, under the conditions of a temperature of 50°C to 150°C and a pressure of 0.02MPa to 1.0MPa, a required amount of hydrocarbon oil and a decalcifying agent aqueous solution are mixed to obtain a mixed solution; then, the mixed solution is treated for 1min to 60min under the condition of an electric field strength of 50V / cm to 500V / cm, and then treated for 5min to 200min under the condition of an electric field strength of 500V / cm to 1500V / cm, to obtain demetallized hydrocarbon oil and a reacted decalcifying agent aqueous solution, respectively, wherein the mass content of the decalcifying agent in the mixed solution is 0.01wt% to 5wt%, the mass content of water is 1% to 25%, and the rest is hydrocarbon oil, and the decalcifying agent is one or more of formic acid, acetic acid, propionic acid and butyric acid.

[0026] According to needs, when the concentration of hydrocarbon oil decalcifying agent in the aqueous solution formed by mixing the decalcifying agent concentrate, water and condensed water after decalcification is higher than the required ratio of decalcifying agent to hydrocarbon oil, a certain amount of water is added until the concentration of hydrocarbon oil decalcifying agent in the aqueous solution meets the required ratio of hydrocarbon oil decalcifying agent to hydrocarbon oil.

[0027] Embodiment 3: As an optimization of the above embodiment, in the third step, the specific process of decalcification treatment is: first, the concentrated solution of the reaction product of calcium ions and the decalcifying agent is mixed with the required amount of precipitant and then subjected to precipitation reaction to obtain a precipitation reaction product; secondly, the precipitation reaction product is subjected to a first solid-liquid separation to obtain a liquid phase product and a solid phase product respectively; then, the solid phase product is washed, separated and dried to obtain a calcium salt product, and the liquid phase product is subjected to a high temperature crystallization reaction to obtain a high temperature crystallization reactant; finally, the high temperature crystallization reactant is subjected to a second solid-liquid separation to obtain a decalcified decalcifying agent concentrated solution.

[0028] Example 4: As an optimization of the above example, the precipitant is sulfuric acid or phosphoric acid, the precipitation reaction temperature is 20°C to 50°C, the reaction time is 5min to 30min, the high temperature crystallization reaction temperature is 100°C to 150°C, and the reaction time is 5min to 30min.

[0029] In the present invention, the amount of the precipitant is the theoretical amount of the precipitant when the precipitant completely reacts with the calcium ions in the concentrated solution of the reaction product of the calcium ions and the decalcifying agent.

[0030] The conditions for the first solid-liquid separation in the present invention include: a temperature of 20°C to 50°C and a pressure of -0.1 MPa to 1.0 MPa, and the conditions for the second solid-liquid separation include: a temperature of 100°C to 150°C and a pressure of 0.1 MPa to 1.0 MPa. As required, the first solid-liquid separation can be performed by static sedimentation, a centrifuge or a filter, and the second solid-liquid separation can be performed by static sedimentation or a filter.

[0031] The specific steps of obtaining the calcium salt product in the present invention are: washing the solid phase product (calcium salt slag) obtained by the precipitation reaction and the high-temperature crystallization reaction with water at 20°C to 50°C until the pH value of the washed water is 6 to 7, and stopping the washing; then separating the slag by static sedimentation, centrifugation or using a filter at 20°C to 50°C and -0.1MPa to 1.0MPa, and drying at 100°C to 200°C until the moisture content is less than or equal to 1wt% (mass content), so as to obtain the calcium salt product, which can be used as a building product.

[0032] Example 5: As an optimization of the above example, in the second step, the specific process of membrane separation treatment includes: first, passing the decalcifying agent aqueous solution after the reaction through a nanofiltration membrane for at least one stage of nanofiltration treatment to obtain a concentrated solution and a filtrate of the reaction product of calcium ions and the decalcifying agent; then, passing the filtrate through a reverse osmosis membrane for at least one stage of reverse osmosis treatment to obtain a first sodium ion-containing filtrate and fresh water.

[0033] Example 6: As an optimization of the above example, the decalcification agent aqueous solution after the reaction is subjected to two-stage nanofiltration treatment through a nanofiltration membrane, and the filtrate is subjected to one-stage reverse osmosis treatment through a reverse osmosis membrane, wherein the pressure of the nanofiltration treatment is 0.2 MPa to 2.0 MPa, the nanofiltration membrane is a monovalent ion selective nanofiltration membrane, the material of the nanofiltration membrane is one or more of aromatic polyamide, polypiperazineamide, cellulose acetate and sulfonated polyether sulfone, preferably aromatic polyamide, the pressure of the reverse osmosis treatment is 2.0 MPa to 6.0 MPa, the material of the reverse osmosis membrane is one or more of aromatic polyamide, polypiperazineamide, polyimide and sulfonated polysulfone, preferably polypiperazineamide.

[0034] According to the needs, in the present invention, when the pressure of the nanofiltration treatment meets 0.2MPa to 2.0MPa, the nanofiltration treatment is carried out by cross-flow filtration, and the recovery rate of the filtrate is 50% to 85%. The recovery rate of the filtrate is related to the calcium ion concentration in the hydrocarbon oil, and the recovery rate of the filtrate decreases with the increase of the calcium ion concentration. The retention rate of calcium and magnesium ions through the monovalent ion selective permeation nanofiltration membrane is 95% to 99%, and the retention rate of sodium ions is 1% to 10%. When the pressure of the reverse osmosis treatment meets 2.0MPa to 6.0MPa, the single-stage reverse osmosis treatment is carried out by cross-flow filtration, and the retention rate of sodium salt reaches 97% to 98%, and the fresh water recovery rate is 75% to 85%.

[0035] As needed, the nanofiltration membrane is selected from a rolled nanofiltration membrane, a tubular nanofiltration membrane, a hollow fiber nanofiltration membrane or a plate nanofiltration membrane, preferably a rolled nanofiltration membrane or a tubular nanofiltration membrane, and the reverse osmosis membrane is a plate reverse osmosis membrane, a tubular reverse osmosis membrane or a rolled reverse osmosis membrane, preferably a rolled reverse osmosis membrane.

[0036] In the present invention, for calcium-containing hydrocarbon oil with a high sodium chloride content, the Na ion content in the post-reaction decalcifying agent aqueous solution obtained after the electrical desalting treatment is also high. Therefore, for the post-reaction decalcifying agent aqueous solution with a high Na ion content obtained after the electrical desalting treatment, especially the post-reaction decalcifying agent aqueous solution with a Na content greater than or equal to 200 μg / g, a two-stage nanofiltration treatment is performed, and the two-stage nanofiltration treatments both use a nanofiltration membrane made of aromatic polyamide, wherein the first-stage nanofiltration treatment uses a tubular nanofiltration membrane, and the second-stage nanofiltration treatment uses a roll nanofiltration membrane, and then the obtained filtrate is subjected to reverse osmosis treatment through a roll reverse osmosis membrane made of polypiperazineamide, which can remove metal ions such as Ca, Mg and Na in the water, especially the removal of Na, eliminates the influence of water-soluble sodium salt on the electrical desalting of crude oil, realizes the complete regeneration of decalcified wastewater and performs long-term cyclic utilization, and can well realize the resource utilization of decalcified wastewater.

[0037] Example 7: As an optimization of the above example, the specific process of membrane separation treatment also includes: pre-treating the aqueous decalcifying agent solution after the reaction, and then performing nanofiltration treatment, wherein the pretreatment is to perform microfiltration treatment on the aqueous decalcifying agent solution after the reaction through a microfiltration membrane, and the material of the microfiltration membrane is one or more of ceramic, polypropylene, polycarbonate, polyvinyl chloride, polysulfone, polyvinylidene fluoride and polytetrafluoroethylene.

[0038] In the present invention, the purpose of pretreatment is to remove suspended matter, silt and other impurities in the decalcifying agent aqueous solution after the reaction. According to needs, the microfiltration membrane is selected from one or two of the average pore size (filtration accuracy) of 0.1μm to 0.5μm, 0.5μm to 1μm, 1μm to 5μm and 5μm to 10μm, and the microfiltration purification device can be a combination of microfiltration membranes with different average pore sizes.

[0039] Example 8: As an optimization of the above example, in the fourth step, the evaporation temperature is 120°C to 200°C, the condensation temperature is 20°C to 50°C, and the mass content of the metallic sodium salt in the obtained second sodium ion-containing filtrate is 10% to 30%.

[0040] The concentrated brine containing metallic sodium salt obtained by the invention can be used as a drilling fluid product when the concentration of the sodium chloride solution is adjusted to 10% to 30%.

[0041] According to the needs, the diameter of the oil-water particles of the hydrocarbon oil decalcifying agent aqueous solution and the hydrocarbon oil is controlled within the range of 0.1 μm to 50 μm.

[0042] Example 9: Figure 1As shown, the device and apparatus for implementing the method and apparatus for cyclic demetallation of hydrocarbon oil electro-desalting comprises a hydrocarbon oil storage tank 1, a mixer 2, an electro-desalting tank 3, a microfiltration purification device 6, a nanofiltration device 8, a reverse osmosis device 11, an evaporative condenser 14, a brine storage tank 17, a precipitant storage tank 18, a solidification reaction tank 19, a first solid-liquid separator 21, a high-temperature crystallization reaction tank 26, a second solid-liquid separator 28, and a hydrocarbon oil decalcifying agent aqueous solution tank 30. A mixed liquid inlet pipeline 33 is fixedly connected between the outlet of the hydrocarbon oil storage tank 1 and the inlet of the mixer 2. The outlet of the mixer 2 is connected to the electro-desalting tank 3. The inlet of the desalting tank 3 is fixedly connected with a mixed liquid outlet pipeline 34, the first outlet of the electric desalting tank 3 and the inlet of the microfiltration purification device 6 are fixedly connected with a pipeline 5 for entering the decalcified aqueous solution after reaction, the outlet of the microfiltration purification device 6 and the inlet of the nanofiltration device 8 are fixedly connected with a pre-treated filtrate pipeline 7, the first outlet of the nanofiltration device 8 and the inlet of the reverse osmosis device 11 are fixedly connected with a sodium ion filtrate pipeline 10, the first outlet of the reverse osmosis device 11 and the inlet of the evaporative condenser 14 are fixedly connected with a first sodium ion filtrate pipeline 13, and the evaporative condenser A second sodium ion filtrate pipeline 15 is fixedly connected between the first outlet of the evaporative condenser 14 and the first inlet of the hydrocarbon oil decalcification agent aqueous solution tank 30, an evaporative condensate delivery pipeline 16 is fixedly connected between the second outlet of the nanofiltration device 8 and the first inlet of the solidification reaction tank 19, a concentrated liquid delivery pipeline 9 is fixedly connected between the outlet of the solidification reaction tank 19 and the inlet of the first solid-liquid separator 21, and a feed liquid delivery pipeline 20 is fixedly connected between the first outlet of the first solid-liquid separator 21 and the inlet of the high-temperature crystallization reaction tank 26. A first concentrated water recovery pipeline 22 is fixedly connected between them, a material conveying pipeline 27 is fixedly connected between the outlet of the high-temperature crystallization reaction tank 26 and the inlet of the second solid-liquid separator 28, a second concentrated water recovery pipeline 29 is fixedly connected between the first outlet of the second solid-liquid separator 28 and the second inlet of the hydrocarbon oil decalcification agent aqueous solution tank 30, a recovery solution pipeline 31 is fixedly connected between the outlet of the hydrocarbon oil decalcification agent aqueous solution tank 30 and the mixed liquid inlet pipeline 33, and a precipitant conveying pipeline 35 is fixedly connected between the outlet of the precipitant storage tank 18 and the second inlet of the solidification reaction tank 19.

[0043] Example 10: Figure 1As shown, as an optimization of the above embodiment, an apparatus for implementing the method of cyclic demetallization of hydrocarbon oil by electric desalination also includes a calcium salt slag tank 23 and a drying device 24, a first calcium salt pipeline 36 is fixedly connected between the outlet of the first solid-liquid separator 21 and the first inlet of the calcium salt slag tank 23, a second calcium salt pipeline 37 is fixedly connected between the outlet of the second solid-liquid separator 28 and the second inlet of the calcium salt slag tank 23, a solid phase drying pipeline 38 is fixedly connected between the outlet of the calcium salt slag tank 23 and the inlet of the drying device 24, a calcium sulfate product pipeline 25 is fixedly connected to the outlet of the drying device 24, a demetallized hydrocarbon oil output pipeline 4 is fixedly connected to the second outlet of the electric desalting tank 3, a fresh water delivery pipeline 12 is fixedly connected between the second outlet of the reverse osmosis device 11 and the evaporation condensate delivery pipeline 16, and a water injection pipeline 32 is fixedly connected to the third inlet of the salt slag tank 23 and the third inlet of the hydrocarbon oil decalcification agent aqueous solution tank 30.

[0044] As required, the pipelines and equipment of the method and apparatus for implementing hydrocarbon oil electric desalination cycle demetallization can be provided with conventional valves, thermometers and pressure gauges known in the art according to production needs.

[0045] Example 11: Figure 1 As shown, the method for removing metal ions from hydrocarbon oil by electro-desalting cycle is carried out according to the following steps: The first step is to mix a hydrocarbon oil decalcifying agent and water (based on the weight of the hydrocarbon oil, the mass contents of the hydrocarbon oil decalcifying agent and water are 0.01wt% to 5wt% and 1wt% to 25wt% respectively) to obtain a decalcifying agent aqueous solution, and fully mix the decalcifying agent aqueous solution and the demetallized hydrocarbon oil with a mixer 2 at a mixing pressure difference of 0.02MPa to 1.0MPa at 50°C to 150°C to control the diameter of the oil and water particles within a range of 0.1μm to 50μm, and then place the oil-water mixture in an electric desalting tank 3, and stay for 1min to 60min at a temperature of 50°C to 150°C and an electric field strength of 5V / cm to 500V / cm, and then stay for 5min to 200min at a temperature of 50°C to 150°C and an electric field strength of 500V / cm to 1500V / cm, and after oil and water separation, obtain demetallized hydrocarbon oil and a reacted decalcifying agent aqueous solution; In the second step, the decalcifying agent aqueous solution after the reaction is pretreated by a microfiltration purification device 6 to remove suspended matter, silt and other impurities therein; the pretreated filtrate is sent to a nanofiltration device 8 (using a monovalent ion selective permeable nanofiltration membrane) for treatment at a treatment pressure of 0.2 MPa to 2 MPa, and the divalent calcium and magnesium ions are separated from the monovalent sodium ions by cross-flow filtration to obtain a sodium ion-containing filtrate and a concentrated solution of the reaction product of calcium ions and the decalcifying agent, and the obtained sodium ion-containing filtrate is sent to a reverse osmosis device 11 for reverse osmosis treatment, and the operating pressure of the reverse osmosis system is 2 MPa to 6 MPa to obtain a dilute filtrate free of metal salts and a first sodium ion-containing filtrate; In the third step, in the solidification reaction tank 19, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration device is subjected to precipitation reaction with sulfuric acid flowing out of the precipitant storage tank 18 (the amount of sulfuric acid used is the theoretical amount of sulfuric acid when the calcium ions in the concentrated solution of the reaction product of calcium ions and the decalcifying agent are completely reacted), the reaction temperature is 20°C to 50°C, the time is 5min to 30min, and a feed liquid containing calcium sulfate precipitate is generated; under the conditions of a temperature of 20°C to 50°C and a pressure of -0.1MPa to 1.0MPa, a first solid-liquid separation is performed using a first solid-liquid separator 22 (centrifuge, the speed is 2500r / min3 to 500r / min) to obtain a first recovered concentrated water and calcium sulfate solid residue, the first recovered concentrated water is discharged to a high-temperature crystallization reaction tank 26, a crystallization reaction is performed in the high-temperature crystallization reaction tank 26, the reaction temperature is 100°C to 150°C, the time is 5min to 30min, and a feed liquid containing calcium sulfate crystals is generated, and in Under the conditions of temperature of 100° C. to 150° C. and pressure of 0.1 MPa to 1.0 MPa, a second solid-liquid separation is performed by a second solid-liquid separator 28 to obtain a second recovered concentrate (decalcified decalcifying agent concentrate) and calcium sulfate crystals, and the second recovered concentrate is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank 30, wherein the obtained calcium sulfate solid slag is washed, separated and dried, and the specific steps of obtaining the calcium sulfate product are as follows: at 20° C. to 50° C., the calcium sulfate solid slag is washed with water in a calcium salt slag tank 23 (based on the weight of the calcium sulfate solid slag, the mass amount of water is 50wt% to 200wt%), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water is 6 to 7, and the washing is stopped, and the calcium slag is allowed to stand for sedimentation and stratification at 20° C. to 50° C. and -0.1 MPa to 1.0 MPa, and the separated calcium slag is dried at 100° C. to 200° C. in a drying device 24 until the water content is less than or equal to 1wt%, to obtain a calcium sulfate product; Step 4: In the evaporative condenser 14, the first sodium ion-containing filtrate is evaporated and concentrated at 120° C. to 200° C., and condensed at 20° C. to 50° C. to obtain a second sodium ion-containing filtrate and evaporated condensed water, and the obtained second sodium ion-containing filtrate is stored in a brine storage tank 17; In the fifth step, the evaporated condensed water, the second recovered concentrated water (the decalcifying agent concentrated solution after decalcification) and the fresh water without metal salt are mixed in the hydrocarbon oil decalcifying agent aqueous solution tank 30 to obtain a recovered aqueous solution containing the hydrocarbon oil decalcifying agent. When the concentration of the hydrocarbon oil decalcifying agent in the recovered aqueous solution is higher than the required ratio of the decalcifying agent to the hydrocarbon oil, a certain amount of water is added until the concentration of the hydrocarbon oil decalcifying agent in the aqueous solution meets the required ratio of the hydrocarbon oil decalcifying agent to the hydrocarbon oil, and then the solution is returned to the first step for recycling.

[0046] According to the needs, in the present invention, the analysis method of metal ions in hydrocarbon oil: RIPP124-1990 plasma emission spectrometry; the analysis method of metal ions in water: RIPP124-1990 plasma emission spectrometry; the analysis method of sulfate ions in water: GB 11899 Water quality, determination of sulfate, weight method; the analysis method of phosphate ions in water: GB / T14642-2009 Determination of fluoride, chlorine, phosphate, nitrite, nitrate and sulfate in industrial circulating cooling water and boiler water, ion chromatography; the analysis method of decalcification agent concentration: liquid chromatography.

[0047] Example 12: The hydrocarbon oil to be treated in this example is a minus four fraction oil, and the metal ion contents are: calcium ion 40.4μg / g, magnesium ion 5.13μg / g, sodium ion 2.8μg / g, as shown in FIG. Figure 1 As shown, the method for removing metal ions from hydrocarbon oil by electro-desalting cycle is carried out according to the following steps: In the first step, a hydrocarbon oil decalcifying agent (formic acid) and water are mixed (based on the weight of the oil minus four fractions, the mass contents of the hydrocarbon oil decalcifying agent and water are 0.01wt% and 25wt% respectively) to obtain a decalcifying agent aqueous solution; the decalcifying agent aqueous solution and the oil minus four fractions are fully mixed with a static mixer at a mixing pressure difference of 0.02MPa for 1 minute at 50°C; the oil-water mixture is then placed in an electric desalting tank 3, and stays for 1 minute at a temperature of 50°C and an electric field strength of 50V / cm, and then stays for 5 minutes at a temperature of 50°C and an electric field strength of 500V / cm. After oil-water separation, a demetallized hydrocarbon oil and a decalcifying agent aqueous solution after reaction are obtained (analysis shows that the calcium content in the demetallized hydrocarbon oil is 1.5μg / g, the magnesium content is 0.21μg / g, and the sodium content is 0.8μg / g; the calcium content in the decalcifying agent aqueous solution after reaction is 0.02wt% and the sodium content is 0.001wt%); In the second step, the decalcification agent aqueous solution after the reaction is pretreated by a microfiltration purification device 6 (composed of a two-stage microfiltration system with filtration accuracy of 10 μm and 0.5 μm, respectively, and the materials of the microfiltration membranes are polypropylene and polyvinyl chloride, respectively) to remove suspended matter, sediment and other impurities therein, and the pretreated filtrate is sent to a nanofiltration device 8 (a primary nanofiltration and a secondary nanofiltration, both of which use a monovalent ion selective permeable nanofiltration membrane made of aromatic polyamide, a tubular nanofiltration membrane is used in the primary nanofiltration system, and a roll nanofiltration membrane is used in the secondary nanofiltration system) for treatment, and the treatment pressure is 0.3 MPa. a. Separate divalent calcium and magnesium ions from monovalent sodium ions by cross-flow filtration to obtain a sodium ion-containing filtrate and a concentrated solution of the reaction product of calcium ions and a decalcifying agent (the retention rates of calcium and magnesium ions are 95%, the retention rate of sodium ions is 10%; the recovery rate of the filtrate is 85%), and send the obtained sodium ion-containing filtrate to a reverse osmosis device 11 (using a rolled reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 2 MPa to obtain a fresh water and a first sodium ion-containing filtrate free of metal salts (the retention rate of sodium salts is 97%, and the recovery rate of fresh water is 85%). In the third step, in the solidification reaction tank 19, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration device is subjected to precipitation reaction with sulfuric acid flowing out of the precipitant storage tank 18 (the amount of sulfuric acid used is the theoretical amount of sulfuric acid when the calcium ions in the concentrated solution of the reaction product of calcium ions and the decalcifying agent are completely reacted), the reaction temperature is 50°C, the time is 5min, and a feed liquid containing calcium sulfate precipitate is generated; under the conditions of a temperature of 50°C and a pressure of 1.0MPa, a first solid-liquid separator 22 (centrifuge, a speed of 3000r / min) is used for a first solid-liquid separation to obtain a first recovered concentrated water and a calcium sulfate solid residue, the first recovered concentrated water (sulfate content of 1500mg / L) is discharged to a high-temperature crystallization reaction tank 26, a crystallization reaction is carried out in the high-temperature crystallization reaction tank 26, the reaction temperature is 100°C, the time is 5min, and a feed liquid containing calcium sulfate crystals is generated, and under the conditions of a temperature of 100°C and a pressure of 1.0MPa, a second solid-liquid separation is performed with a second solid-liquid separator 28 (centrifuge, rotating speed is 3000r / min) to obtain a second recovered concentrate (decalcified decalcifying agent concentrate) and calcium sulfate crystals, and the second recovered concentrated water is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank 30; wherein the obtained calcium sulfate solid slag is washed, separated and dried to obtain a calcium sulfate product in the following specific steps: at 40°C, the calcium sulfate solid slag is washed with water in a calcium salt slag tank 23 (based on the weight of the calcium sulfate solid slag, the mass amount of water is 100wt%), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water is 6 and the washing is stopped; allowed to stand for sedimentation and stratification under normal temperature and pressure conditions, and the separated calcium slag is dried in a drying device 24 at 120°C until the water content is less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of calcium sulfate is 92.7wt%, meeting the quality standard of building gypsum); Step 4: In the evaporative condenser 14, the first sodium ion-containing filtrate is evaporated and concentrated at 120° C., and condensed at 20° C. to obtain a second sodium ion-containing filtrate and evaporated condensed water. The obtained second sodium ion-containing filtrate (the mass content of sodium salt is 10wt%, which meets the quality standard of brine drilling fluid) is placed in the brine storage tank 17; In the fifth step, the evaporated condensed water, the second recovered concentrated water (the decalcifying agent concentrated solution after decalcification) and the fresh water without metal salt are mixed in the hydrocarbon oil decalcifying agent aqueous solution tank 30 to obtain a recovered aqueous solution containing the hydrocarbon oil decalcifying agent (the sulfate content is 83 mg / L). When the concentration of the hydrocarbon oil decalcifying agent in the recovered aqueous solution is higher than the required ratio of the decalcifying agent to the hydrocarbon oil, a certain amount of water is added until the concentration of the hydrocarbon oil decalcifying agent in the aqueous solution meets the required ratio of the hydrocarbon oil decalcifying agent to the hydrocarbon oil, and then the solution is returned to the first step for recycling.

[0048] Example 13: The hydrocarbon oil to be treated in this example is crude oil, and the metal ion contents are: calcium ion 520 μg / g, magnesium ion 5.64 μg / g, sodium ion 120.1 μg / g, as shown in FIG. Figure 1 As shown, the method for removing metal ions from hydrocarbon oil by electro-desalting cycle is carried out according to the following steps: The first step is to mix the hydrocarbon oil decalcifying agent (acetic acid) and water (based on the weight of crude oil, the mass contents of the hydrocarbon oil decalcifying agent and water are 0.52wt% and 8wt% respectively) to obtain a decalcifying agent aqueous solution; the decalcifying agent aqueous solution and the crude oil are fully mixed with a stirrer for 30 minutes at 150°C and a pressure of 1.0MPa; then the oil-water mixture is placed in an electric desalting tank 3, and stays for 60 minutes at a temperature of 150°C and an electric field strength of 500V / cm, and then stays for 200 minutes at a temperature of 150°C and an electric field strength of 1000V / cm. After oil and water separation, demetallized hydrocarbon oil and a decalcifying agent aqueous solution after reaction are obtained (analysis shows that the calcium content of the demetallized hydrocarbon oil is 13.2μg / g, the magnesium content is 0.2μg / g, and the sodium content is 1.0μg / g; the calcium content of the decalcifying agent aqueous solution after reaction is 0.25wt%, and the sodium content is 0.059wt%); In the second step, the decalcification agent aqueous solution after the reaction is pretreated by a microfiltration purification device 6 (composed of a two-stage microfiltration system with filtration accuracy of 5 μm and 0.1 μm, respectively, and the materials of the microfiltration membranes are ceramic and polycarbonate, respectively) to remove suspended matter, sediment and other impurities therein, and the pretreated filtrate is sent to a nanofiltration device 8 (a primary nanofiltration and a secondary nanofiltration, both of which use a monovalent ion selective permeable nanofiltration membrane made of aromatic polyamide, the primary nanofiltration system uses a tubular nanofiltration membrane, and the secondary nanofiltration system uses a roll nanofiltration membrane) for treatment, and the treatment pressure is 2.0 MPa. By adopting a cross-flow filtration method, divalent calcium and magnesium ions are separated from monovalent sodium ions to obtain a sodium ion-containing filtrate and a concentrated solution of a reaction product of calcium ions and a decalcifying agent (the retention rates of calcium and magnesium ions are 96%, the retention rate of sodium ions is 10%; the recovery rate of the filtrate is 85%), and the obtained sodium ion-containing filtrate is sent to a reverse osmosis device 11 (using a roll reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 2.0 MPa, and a fresh water and a first sodium ion-containing filtrate free of metal salts are obtained (the retention rate of sodium salts is 98%, and the recovery rate of fresh water is 75%). In the third step, in the solidification reaction tank 19, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration device is subjected to precipitation reaction with sulfuric acid flowing out of the precipitant storage tank 18 (the amount of sulfuric acid used is the theoretical amount of sulfuric acid when the calcium ions in the concentrated solution of the reaction product of calcium ions and the decalcifying agent are completely reacted), the reaction temperature is 45°C, the time is 30 minutes, and a feed liquid containing calcium sulfate precipitate is generated; under the conditions of a temperature of 45°C and a pressure of 0.15MPa, a first solid-liquid separator 22 (filter) is used to perform a first solid-liquid separation to obtain a first recovered concentrated water and a calcium sulfate solid residue, and the first recovered concentrated water (sulfate content is 780mg / L) is discharged to a high-temperature crystallization reaction tank 26, and a crystallization reaction is carried out in the high-temperature crystallization reaction tank 26, the reaction temperature is 150°C, the time is 30 minutes, and a feed liquid containing calcium sulfate crystals is generated, and the temperature is 150°C and the pressure is 0.15MPa. Under the condition of 0.1MPa, a second solid-liquid separator 28 (filter) is used to perform a second solid-liquid separation to obtain a second recovered concentrate (decalcified decalcifying agent concentrate) and calcium sulfate crystals, and the second recovered concentrated water is discharged into the hydrocarbon oil decalcifying agent aqueous solution tank 30; wherein, the obtained calcium sulfate solid slag is washed, separated and dried to obtain the calcium sulfate product in the specific steps of: at 50°C, the calcium sulfate solid slag is washed with water in the calcium salt slag tank 23 (based on the weight of the calcium sulfate solid slag, the mass amount of water is 160wt%), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water is 7 and the washing is stopped; the calcium slag is allowed to stand for sedimentation and stratification under normal temperature and pressure conditions, and the separated calcium slag is dried at 120°C in the drying device 24 until the water content is less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of calcium sulfate is 93.1wt%, meeting the quality standard of building gypsum); Step 4: In the evaporative condenser 14, the first sodium ion-containing filtrate is evaporated and concentrated at 200° C., and condensed at 50° C. to obtain a second sodium ion-containing filtrate and evaporated condensed water. The obtained second sodium ion-containing filtrate (the mass content of sodium salt is 30wt%, which meets the quality standard of brine drilling fluid) is placed in the brine storage tank 17; In the fifth step, the evaporated condensed water, the second recovered concentrated water (the decalcifying agent concentrated solution after decalcification) and the fresh water without metal salt are mixed in the hydrocarbon oil decalcifying agent aqueous solution tank 30 to obtain a recovered aqueous solution containing the hydrocarbon oil decalcifying agent (the sulfate content is 55 mg / L). When the concentration of the hydrocarbon oil decalcifying agent in the recovered aqueous solution is higher than the required ratio of the decalcifying agent to the hydrocarbon oil, a certain amount of water is added until the concentration of the hydrocarbon oil decalcifying agent in the aqueous solution meets the required ratio of the hydrocarbon oil decalcifying agent to the hydrocarbon oil, and then the solution is returned to the first step for recycling.

[0049] Example 14: The hydrocarbon oil to be treated in this example is thick oil, and the metal ion contents are: calcium ion 712μg / g, magnesium ion 2.53μg / g, sodium ion 95.8μg / g, as shown in FIG. Figure 1As shown, the method for removing metal ions from hydrocarbon oil by electro-desalting cycle is carried out according to the following steps: In the first step, a hydrocarbon oil decalcifying agent (propionic acid) and water are mixed (based on the weight of the heavy oil, the mass contents of the hydrocarbon oil decalcifying agent and water are 0.25wt% and 20wt% respectively) to obtain a decalcifying agent aqueous solution; the decalcifying agent aqueous solution and the heavy oil are sheared for 15 minutes using an emulsifying shearing instrument at 120° C., and then the oil-water mixture is placed in an electric desalting tank 3, and stays for 30 minutes at a temperature of 120° C. and an electric field strength of 400V / cm, and then stays for 150 minutes at a temperature of 120° C. and an electric field strength of 1500V / cm. After oil-water separation, demetallized hydrocarbon oil and a decalcifying agent aqueous solution after reaction are obtained (analysis shows that the calcium content of the hydrocarbon oil after metal ion removal is 25.8μg / g, the magnesium content is 0.35μg / g, and the sodium content is 1.3μg / g; the calcium content of the decalcifying agent aqueous solution after reaction is 0.34wt%, and the sodium content is 0.047wt%); In the second step, the decalcification agent aqueous solution after the reaction is pretreated by a microfiltration purification device 6 (composed of a two-stage microfiltration system with filtration accuracy of 5 μm and 0.1 μm, respectively, and the materials of the microfiltration membranes are polypropylene and polysulfone, respectively) to remove suspended matter, sediment and other impurities therein, and the pretreated filtrate is sent to a nanofiltration device 8 (a primary nanofiltration and a secondary nanofiltration, both of which use a monovalent ion selective permeable nanofiltration membrane made of aromatic polyamide, the primary nanofiltration system uses a tubular nanofiltration membrane, and the secondary nanofiltration system uses a roll nanofiltration membrane) for treatment, and the treatment pressure is 0.2 MPa. A cross-flow filtration method is adopted to separate divalent calcium and magnesium ions from monovalent sodium ions, and a sodium ion-containing filtrate and a concentrated solution of the reaction product of calcium ions and a decalcifying agent are obtained (the retention rates of calcium and magnesium ions are 99%, the retention rate of sodium ions is 1%; the recovery rate of the filtrate is 84%), and the obtained sodium ion-containing filtrate is sent to a reverse osmosis device 11 (using a roll-type reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 4.0 MPa, and a fresh water and a first sodium ion-containing filtrate free of metal salts are obtained (the retention rate of sodium salts is 97%, and the recovery rate of fresh water is 80%). In the third step, in the solidification reaction tank 19, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration device is subjected to precipitation reaction with sulfuric acid flowing out of the precipitant storage tank 18 (the amount of sulfuric acid used is the theoretical amount of sulfuric acid when the calcium ions in the concentrated solution of the reaction product of calcium ions and the decalcifying agent are completely reacted), the reaction temperature is 30°C, the time is 10 min, and a feed liquid containing calcium sulfate precipitate is generated; under the conditions of a temperature of 30°C and a pressure of -0.08 MPa, a first solid-liquid separator 22 (suction filter) is used to perform a first solid-liquid separation to obtain a first recovered concentrated water and a calcium sulfate solid residue, and the first recovered concentrated water (sulfate content of 1180 mg / L) is discharged to a high-temperature crystallization reaction tank 26, and a crystallization reaction is carried out in the high-temperature crystallization reaction tank 26, the reaction temperature is 120°C, the time is 20 min, and a feed liquid containing calcium sulfate crystals is generated, and the temperature is 120°C and the pressure is -0.08 MPa. Under the condition of 0.5MPa, a second solid-liquid separator 28 is used to perform a second solid-liquid separation to obtain a second recovered concentrate (decalcified decalcifying agent concentrate) and calcium sulfate crystals, and the second recovered concentrated water is discharged into the hydrocarbon oil decalcifying agent aqueous solution tank 30; wherein, the obtained calcium sulfate solid slag is washed, separated and dried to obtain the calcium sulfate product in the specific steps of: washing the calcium sulfate solid slag with water in a calcium salt slag tank 23 at 20°C to 50°C (based on the weight of the calcium sulfate solid slag, the mass amount of water is 200wt%), standing and stratifying, and repeatedly washing with water until the pH value of the washing water is 6.2 and the washing is stopped; standing and settling at normal temperature and pressure, and the separated calcium slag is dried in a drying device 24 at 120°C to a water content of less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of calcium sulfate is 92.7wt%, reaching the quality standard of building gypsum); Step 4: In the evaporative condenser 14, the first sodium ion-containing filtrate is evaporated and concentrated at 160° C., and condensed at 40° C. to obtain a second sodium ion-containing filtrate and evaporated condensed water. The obtained second sodium ion-containing filtrate (the mass content of sodium salt is 20wt%, which meets the quality standard of brine drilling fluid) is placed in the brine storage tank 17; In the fifth step, the evaporated condensed water, the second recovered concentrated water (the decalcifying agent concentrated solution after decalcification) and the fresh water without metal salt are mixed in the hydrocarbon oil decalcifying agent aqueous solution tank 30 to obtain a recovered aqueous solution containing the hydrocarbon oil decalcifying agent (the sulfate content is 46 mg / L). When the concentration of the hydrocarbon oil decalcifying agent in the recovered aqueous solution is higher than the required ratio of the decalcifying agent to the hydrocarbon oil, a certain amount of water is added until the concentration of the hydrocarbon oil decalcifying agent in the aqueous solution meets the required ratio of the hydrocarbon oil decalcifying agent to the hydrocarbon oil, and then the solution is returned to the first step for recycling.

[0050] Example 15: The hydrocarbon oil to be treated in this example is super-heavy oil, and the metal ion contents are: calcium ion 1380 μg / g, magnesium ion 14.32 μg / g, sodium ion 282 μg / g, as shown in FIG. Figure 1As shown, the method for removing metal ions from hydrocarbon oil by electro-desalting cycle is carried out according to the following steps: In the first step, a hydrocarbon oil decalcifying agent (butyric acid) and water are mixed (based on the weight of the super heavy oil, the mass contents of the hydrocarbon oil decalcifying agent and water are 1.38wt% and 15wt% respectively) to obtain a decalcifying agent aqueous solution; at 120° C., the decalcifying agent aqueous solution and the super heavy oil are fully mixed in a membrane reactor using a metal membrane with a membrane pore size of 10 μm as a membrane material, and then the oil-water mixture is placed in an electric desalting tank 3, and stays for 20 minutes under the conditions of a temperature of 150° C. and an electric field strength of 300V / cm, and then stays for 90 minutes under the conditions of a temperature of 150° C. and an electric field strength of 1400V / cm. After oil and water separation, demetallized hydrocarbon oil and a decalcifying agent aqueous solution after reaction are obtained (analysis shows that the calcium content of the hydrocarbon oil after metal ion removal is 37.8μg / g, the magnesium content is 0.78μg / g, and the sodium content is 1.5μg / g; the calcium content of the decalcifying agent aqueous solution after reaction is 0.67wt%, and the sodium content is 0.14wt%); In the second step, the decalcification agent aqueous solution after the reaction is pretreated by a microfiltration purification device 6 (composed of a two-stage microfiltration system with filtration accuracies of 10 μm and 1 μm, respectively, and the materials of the microfiltration membranes are polyvinylidene fluoride and polypropylene, respectively) to remove suspended matter, sediment and other impurities therein, and the pretreated filtrate is sent to a nanofiltration device 8 (a primary nanofiltration and a secondary nanofiltration, both of which use a monovalent ion selective permeable nanofiltration membrane made of aromatic polyamide, the primary nanofiltration system uses a tubular nanofiltration membrane, and the secondary nanofiltration system uses a roll nanofiltration membrane) for treatment, and the treatment pressure is 0.3 MPa. , using a cross-flow filtration method to separate divalent calcium and magnesium ions from monovalent sodium ions, obtaining a sodium ion-containing filtrate and a concentrated solution of a reaction product of calcium ions and a decalcifying agent (the retention rates of calcium and magnesium ions are 96%, the retention rate of sodium ions is 7%; the recovery rate of the filtrate is 75%), and sending the obtained sodium ion-containing filtrate to a reverse osmosis device 11 (using a rolled reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 6.0 MPa, and a fresh water and a first sodium ion-containing filtrate free of metal salts are obtained (the retention rate of sodium salts is 98%, and the recovery rate of fresh water is 78%). In the third step, in the solidification reaction tank 19, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration device is subjected to precipitation reaction with sulfuric acid flowing out of the precipitant storage tank 18 (the amount of sulfuric acid used is the theoretical amount of sulfuric acid when the calcium ions in the concentrated solution of the reaction product of calcium ions and the decalcifying agent are completely reacted), the reaction temperature is 30°C, the time is 15min, and a feed liquid containing calcium sulfate precipitate is generated; under the conditions of a temperature of 30°C and a pressure of 0.02MPa, a first solid-liquid separator 22 (suction filter) is used to perform a first solid-liquid separation to obtain a first recovered concentrated water and a calcium sulfate solid residue, and the first recovered concentrated water (sulfate content of 1310mg / L) is discharged to a high-temperature crystallization reaction tank 26, and a crystallization reaction is carried out in the high-temperature crystallization reaction tank 26, the reaction temperature is 130°C, the time is 15min, and a feed liquid containing calcium sulfate crystals is generated, and the temperature is 130°C and the pressure is 0.7M Pa, a second solid-liquid separator 28 is used to perform a second solid-liquid separation to obtain a second recovered concentrate (decalcified decalcifying agent concentrate) and calcium sulfate crystals, and the second recovered concentrated water is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank 30; wherein the obtained calcium sulfate solid slag is washed, separated and dried to obtain a calcium sulfate product in the following specific steps: at 20°C to 50°C, the calcium sulfate solid slag is washed with water in a calcium salt slag tank 23 (based on the weight of the calcium sulfate solid slag, the mass amount of water is 150wt%), allowed to stand and stratify, and repeatedly washed with water until the pH value of the washing water is 7 and the washing is stopped; suction filtration is performed at a temperature of 30°C and a pressure of -0.5MPa, and the separated calcium slag is dried at 150°C in a drying device 24 until the water content is less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of calcium sulfate is 94.3wt%, meeting the quality standard of building gypsum); Step 4: In the evaporative condenser 14, the first sodium ion-containing filtrate is evaporated and concentrated at 120° C., and condensed at 30° C. to obtain a second sodium ion-containing filtrate and evaporated condensed water. The obtained second sodium ion-containing filtrate (the mass content of sodium salt is 30wt%, which meets the quality standard of brine drilling fluid) is placed in the brine storage tank 17; In the fifth step, the evaporated condensed water, the second recovered concentrated water (the decalcifying agent concentrated solution after decalcification) and the fresh water without metal salt are mixed in the hydrocarbon oil decalcifying agent aqueous solution tank 30 to obtain a recovered aqueous solution containing the hydrocarbon oil decalcifying agent (the sulfate content is 45 mg / L). When the concentration of the hydrocarbon oil decalcifying agent in the recovered aqueous solution is higher than the required ratio of the decalcifying agent to the hydrocarbon oil, a certain amount of water is added until the concentration of the hydrocarbon oil decalcifying agent in the aqueous solution meets the required ratio of the hydrocarbon oil decalcifying agent to the hydrocarbon oil, and then the solution is returned to the first step for recycling.

[0051] Example 16: The hydrocarbon oil to be treated in this example is waste oil, and the metal ion contents are: calcium ion 27.3μg / g, magnesium ion 0.32μg / g, sodium ion 0.8μg / g, as shown in FIG. Figure 1As shown, the method for removing metal ions from hydrocarbon oil by electro-desalting cycle is carried out according to the following steps: In the first step, a hydrocarbon oil decalcifying agent (acetic acid) and water are mixed (based on the weight of the waste oil, the mass contents of the hydrocarbon oil decalcifying agent and water are 0.01wt% and 1wt% respectively) to obtain a decalcifying agent aqueous solution. The decalcifying agent aqueous solution and the waste oil are fully mixed with a stirrer for 15 minutes at a temperature of 50°C and a pressure of 0.02MPa. The oil-water mixture is then placed in an electric desalting tank 3, and allowed to stay for 20 minutes at a temperature of 50°C and an electric field strength of 50V / cm, and then allowed to stay for 50 minutes at a temperature of 50°C and an electric field strength of 500V / cm. After oil-water separation, demetallized hydrocarbon oil and a decalcifying agent aqueous solution after reaction are obtained (analysis shows that the calcium content in the hydrocarbon oil after metal ion removal is 0.5μg / g, the magnesium content is 0.2μg / g, and the sodium content is 0.5μg / g; the calcium content in the decalcifying agent aqueous solution after reaction is 0.014wt% and the sodium content is 0.0002wt%). In the second step, the decalcification agent aqueous solution after the reaction is pretreated by a microfiltration purification device 6 (composed of a two-stage microfiltration system with filtration precisions of 8 μm and 0.4 μm, respectively, and the materials of the microfiltration membranes are polycarbonate and polytetrafluoroethylene, respectively) to remove suspended matter, silt and other impurities therein, and the pretreated filtrate is sent to a nanofiltration device 8 (a primary nanofiltration and a secondary nanofiltration, both of which use a monovalent ion selective permeable nanofiltration membrane made of aromatic polyamide, a tubular nanofiltration membrane is used in the primary nanofiltration system, and a roll nanofiltration membrane is used in the secondary nanofiltration system) for treatment, and the treatment pressure is 1.8 MPa. a. Separate divalent calcium and magnesium ions from monovalent sodium ions by cross-flow filtration to obtain a sodium ion-containing filtrate and a concentrated solution of the reaction product of calcium ions and a decalcifying agent (the retention rates of calcium and magnesium ions are 96%, the retention rate of sodium ions is 2%; the recovery rate of the filtrate is 83%), and send the obtained sodium ion-containing filtrate to a reverse osmosis device 11 (using a spiral reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 6.0 MPa to obtain a fresh water and a first sodium ion-containing filtrate free of metal salts (the retention rate of sodium salts is 97%, and the recovery rate of fresh water is 85%). In the third step, in the solidification reaction tank 19, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration device is subjected to precipitation reaction with sulfuric acid flowing out of the precipitant storage tank 18 (the amount of sulfuric acid used is the theoretical amount of sulfuric acid when the calcium ions in the concentrated solution of the reaction product of calcium ions and the decalcifying agent are completely reacted), the reaction temperature is 30°C, the time is 10min, and a feed liquid containing calcium sulfate precipitate is generated; under the conditions of a temperature of 30°C and a pressure of -0.08MPa, a first solid-liquid separation is performed using a first solid-liquid separator 22 (centrifuge, the speed is 3000r / min) to obtain a first recovered concentrated water and calcium sulfate solid residue, the first recovered concentrated water (sulfate content is 1710mg / L) is discharged to a high-temperature crystallization reaction tank 26, a crystallization reaction is performed in the high-temperature crystallization reaction tank 26, the reaction temperature is 100°C, the time is 5min, a feed liquid containing calcium sulfate crystals is generated, and the temperature is 100 ℃, pressure of 1.0MPa, using a second solid-liquid separator 28 for second solid-liquid separation, to obtain a second recovery concentrate (decalcification agent concentrate after decalcification) and calcium sulfate crystals, the second recovery concentrate is discharged to the hydrocarbon oil decalcification agent aqueous solution tank 30; wherein the obtained calcium sulfate solid residue is washed, separated and dried, and the specific steps of obtaining the calcium sulfate product are: at 25℃, the calcium sulfate solid residue is washed with water in the calcium salt slag tank 23 (based on the weight of the calcium sulfate solid residue, the mass amount of water is 50wt%), allowed to stand and stratify, and the washing is repeated until the pH value of the washing water is 6.9 and the washing is stopped; at 25℃, the pressure is -0.75MPa, the calcium residue is allowed to stand and settle and stratify, and the separated calcium residue is dried at 175℃ in the drying device 24 until the water content is less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of calcium sulfate is 98.2wt%, reaching the quality standard of building gypsum); Step 4: In the evaporative condenser 14, the first sodium ion-containing filtrate is evaporated and concentrated at 160° C., and condensed at 50° C. to obtain a second sodium ion-containing filtrate and evaporated condensed water. The obtained second sodium ion-containing filtrate (the mass content of sodium salt is 10wt%, which meets the quality standard of brine drilling fluid) is placed in the brine storage tank 17; In the fifth step, the evaporated condensed water, the second recovered concentrated water (the decalcifying agent concentrated solution after decalcification) and the fresh water without metal salt are mixed in the hydrocarbon oil decalcifying agent aqueous solution tank 30 to obtain a recovered aqueous solution containing the hydrocarbon oil decalcifying agent (the sulfate content is 48 mg / L). When the concentration of the hydrocarbon oil decalcifying agent in the recovered aqueous solution is higher than the required ratio of the decalcifying agent to the hydrocarbon oil, a certain amount of water is added until the concentration of the hydrocarbon oil decalcifying agent in the aqueous solution meets the required ratio of the hydrocarbon oil decalcifying agent to the hydrocarbon oil, and then the solution is returned to the first step for recycling.

[0052] Example 17: The hydrocarbon oil to be treated in this example is crude oil, and the metal ion contents are: calcium ion 208 μg / g, magnesium ion 3.14 μg / g, sodium ion 41.7 μg / g, as shown in FIG. Figure 1As shown, the method for removing metal ions from hydrocarbon oil by electro-desalting cycle is carried out according to the following steps: In the first step, a hydrocarbon oil decalcifying agent (acetic acid) and water are mixed (based on the weight of crude oil, the mass contents of the hydrocarbon oil decalcifying agent and water are 0.07wt% and 7wt% respectively) to obtain a decalcifying agent aqueous solution; the decalcifying agent aqueous solution and the crude oil are fully mixed with a state mixer at 130° C. and a pressure of 0.08MPa for 10 minutes, and then the oil-water mixture is placed in an electric desalting tank 3, and stays for 40 minutes at a temperature of 130° C. and an electric field strength of 300V / cm, and then stays for 100 minutes at a temperature of 130° C. and an electric field strength of 900V / cm. After oil and water separation, a demetallized hydrocarbon oil and a decalcifying agent aqueous solution after reaction are obtained (analysis shows that the calcium content of the hydrocarbon oil after demetallization is 23.9μg / g, the magnesium content is 0.41μg / g, and the sodium content is 1.8μg / g; the calcium content of the decalcifying agent aqueous solution after reaction is 0.09wt%, and the sodium content is 0.02wt%); In the second step, the decalcification agent aqueous solution after the reaction is pretreated by a microfiltration purification device 6 (composed of a two-stage microfiltration system with filtration accuracies of 6 μm and 2 μm, respectively, and the materials of the microfiltration membranes are ceramic and polycarbonate, respectively) to remove suspended matter, sediment and other impurities therein, and the pretreated filtrate is sent to a nanofiltration device 8 (a primary nanofiltration and a secondary nanofiltration, both of which use a monovalent ion selective permeable nanofiltration membrane made of aromatic polyamide, a tubular nanofiltration membrane is used in the primary nanofiltration system, and a roll nanofiltration membrane is used in the secondary nanofiltration system) for treatment, the treatment pressure is 0.8 MPa, and the The divalent calcium and magnesium ions are separated from the monovalent sodium ions by cross-flow filtration to obtain a sodium ion-containing filtrate and a concentrated solution of the reaction product of calcium ions and the decalcifying agent (the retention rates of calcium and magnesium ions are 95.3%, the retention rate of sodium ions is 4%; the recovery rate of the filtrate is 85%), and the obtained sodium ion-containing filtrate is sent to a reverse osmosis device 11 (using a roll reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 4.0 MPa to obtain a fresh water without metal salt and a first sodium ion-containing filtrate (the retention rate of sodium salt is 97%, and the recovery rate of fresh water is 85%). The third step is to carry out precipitation reaction in the solidification reaction tank 19 with the concentrated solution of the reaction product of calcium ions and the decalcifying agent discharged from the nanofiltration device and the sulfuric acid discharged from the precipitant storage tank 18 (the amount of sulfuric acid used is the theoretical amount of sulfuric acid when the calcium ions in the concentrated solution of the reaction product of calcium ions and the decalcifying agent are completely reacted), the reaction temperature is 35°C, the time is 30min, and a feed liquid containing calcium sulfate precipitate is generated; under the conditions of a temperature of 35°C and a pressure of 0.25, a first solid-liquid separation is carried out using a first solid-liquid separator 22 (filter) to obtain a first recovered concentrated water and a calcium sulfate solid residue, and the first recovered concentrated water (sulfate content of 1820 mg / L) is discharged to a high-temperature crystallization reaction tank 26, and a crystallization reaction is carried out in the high-temperature crystallization reaction tank 26, the reaction temperature is 150°C, the time is 30min, and a feed liquid containing calcium sulfate crystals is generated, and under the conditions of a temperature of 150°C and a pressure of 0.8MPa, , using a second solid-liquid separator 28 (filter) to perform a second solid-liquid separation to obtain a second recovered concentrate (decalcified decalcifying agent concentrate) and calcium sulfate crystals, and the second recovered concentrate is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank 30, wherein the obtained calcium sulfate solid residue is washed, separated and dried, and the specific steps of obtaining the calcium sulfate product are: at 35°C, the calcium sulfate solid residue is washed with water in a calcium salt slag tank 23 (based on the weight of the calcium sulfate solid residue, the mass amount of water is 100wt%), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water is 7 and the washing is stopped; centrifugation is performed at 35°C and normal pressure using a centrifuge at a speed of 3500r / min, and the separated calcium residue is dried at 160°C in a drying device 24 until the water content is less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of calcium sulfate is 95.2wt%, meeting the quality standard of building gypsum); Step 4: In the evaporative condenser 14, the first sodium ion-containing filtrate is evaporated and concentrated at 200° C., and condensed at 40° C. to obtain a second sodium ion-containing filtrate and evaporated condensed water. The obtained second sodium ion-containing filtrate (the mass content of sodium salt is 18wt%, which meets the quality standard of brine drilling fluid) is placed in the brine storage tank 17; In the fifth step, the evaporated condensed water, the second recovered concentrated water (the decalcifying agent concentrated solution after decalcification) and the fresh water without metal salt are mixed in the hydrocarbon oil decalcifying agent aqueous solution tank 30 to obtain a recovered aqueous solution containing the hydrocarbon oil decalcifying agent (the sulfate content is 52 mg / L). When the concentration of the hydrocarbon oil decalcifying agent in the recovered aqueous solution is higher than the required ratio of the decalcifying agent to the hydrocarbon oil, a certain amount of water is added until the concentration of the hydrocarbon oil decalcifying agent in the aqueous solution meets the required ratio of the hydrocarbon oil decalcifying agent to the hydrocarbon oil, and then the solution is returned to the first step for recycling.

[0053] Example 18: The hydrocarbon oil to be treated in this example is residual oil, and the metal ion contents are: calcium ion 1469 μg / g, magnesium ion 4.3 μg / g, sodium ion 123.5 μg / g, as shown in FIG. Figure 1As shown, the method for removing metal ions from hydrocarbon oil by electro-desalting cycle is carried out according to the following steps: In the first step, a hydrocarbon oil decalcifying agent (formic acid) and water are mixed (based on the weight of the residual oil, the mass contents of the hydrocarbon oil decalcifying agent and water are 1.47wt% and 11wt% respectively) to obtain a decalcifying agent aqueous solution; the decalcifying agent aqueous solution and the residual oil are mixed with an emulsifying shearing instrument at 135°C and 0.6MPa; the oil-water mixture is then placed in an electric desalting tank 3, and is kept for 30 minutes at a temperature of 135°C and an electric field strength of 200V / cm, and then kept for 150 minutes at a temperature of 135°C and an electric field strength of 1100V / cm, and after oil-water separation, a demetallized hydrocarbon oil and a reacted decalcifying agent aqueous solution are obtained; In the second step, the decalcification agent aqueous solution after the reaction is pretreated by a microfiltration purification device 6 (composed of a two-stage microfiltration system with filtration accuracies of 8 μm and 0.8 μm, respectively, and the materials of the microfiltration membranes are ceramic and polypropylene, respectively) to remove suspended matter, sediment and other impurities therein, and the pretreated filtrate is sent to a nanofiltration device 8 (a primary nanofiltration and a secondary nanofiltration, both of which use a monovalent ion selective permeable nanofiltration membrane made of aromatic polyamide, the primary nanofiltration system uses a tubular nanofiltration membrane, and the secondary nanofiltration system uses a roll nanofiltration membrane) for treatment, the treatment pressure is 2.0 MPa, and the By cross-flow filtration, divalent calcium and magnesium ions are separated from monovalent sodium ions to obtain a sodium ion-containing filtrate and a concentrated solution of the reaction product of calcium ions and a decalcifying agent (the retention rates of calcium and magnesium ions are 96%, the retention rate of sodium ions is 10%; the recovery rate of the filtrate is 75%), and the obtained sodium ion-containing filtrate is sent to a reverse osmosis device 11 (using a roll reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 5.0 MPa, and a fresh water and a first sodium ion-containing filtrate free of metal salts are obtained (the retention rate of sodium salts is 98%, and the recovery rate of fresh water is 75%). In the third step, in the solidification reaction tank 19, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration device is subjected to precipitation reaction with sulfuric acid flowing out of the precipitant storage tank 18 (the amount of sulfuric acid used is the theoretical amount of sulfuric acid when the calcium ions in the concentrated solution of the reaction product of calcium ions and the decalcifying agent are completely reacted), the reaction temperature is 40°C, the time is 30min, and a feed liquid containing calcium sulfate precipitate is generated; under the conditions of a temperature of 40°C and a pressure of 0.35MPa, a first solid-liquid separation is performed using a first solid-liquid separator 22 (hydrocyclone separator) to obtain a first recovered concentrated water and a calcium sulfate solid residue, the first recovered concentrated water (sulfate content of 1580mg / L) is discharged to a high-temperature crystallization reaction tank 26, a crystallization reaction is performed in the high-temperature crystallization reaction tank 26, the reaction temperature is 150°C, the time is 5min, a feed liquid containing calcium sulfate crystals is generated, and the temperature is 150°C and the pressure is Under the condition of 0.35MPa, a second solid-liquid separation is performed by a second solid-liquid separator 28 (cyclone separator) to obtain a second recovered concentrate (decalcified decalcifying agent concentrate) and calcium sulfate crystals, and the second recovered concentrated water is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank 30; wherein the obtained calcium sulfate solid slag is washed, separated and dried to obtain a calcium sulfate product in the specific steps of: washing the calcium sulfate solid slag with water in a calcium salt slag tank 23 at 40°C (based on the weight of the calcium sulfate solid slag, the mass amount of water is 100wt%), standing and stratifying, and repeatedly washing with water until the pH value of the washing water is 7 and the washing is stopped; standing and settling at normal temperature and pressure, and the separated calcium slag is dried in a drying device 24 at 160°C until the water content is less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of calcium sulfate is 96.2wt%, meeting the quality standard of building gypsum); Step 4: In the evaporative condenser 14, the first sodium ion-containing filtrate is evaporated and concentrated at 150° C., and condensed at 20° C. to obtain a second sodium ion-containing filtrate and evaporated condensed water. The obtained second sodium ion-containing filtrate (the mass content of sodium salt is 17wt%, which meets the quality standard of brine drilling fluid) is placed in the brine storage tank 17; In the fifth step, the evaporated condensed water, the second recovered concentrated water (the decalcifying agent concentrated solution after decalcification) and the fresh water without metal salt are mixed in the hydrocarbon oil decalcifying agent aqueous solution tank 30 to obtain a recovered aqueous solution containing the hydrocarbon oil decalcifying agent (the sulfate content is 45 mg / L). When the concentration of the hydrocarbon oil decalcifying agent in the recovered aqueous solution is higher than the required ratio of the decalcifying agent to the hydrocarbon oil, a certain amount of water is added until the concentration of the hydrocarbon oil decalcifying agent in the aqueous solution meets the required ratio of the hydrocarbon oil decalcifying agent to the hydrocarbon oil, and then the solution is returned to the first step for recycling.

[0054] Example 19: The hydrocarbon oil to be treated in this example is super-heavy oil, and the metal ion contents are: calcium ion 1980 μg / g, magnesium ion 23.7 μg / g, sodium ion 98.1 μg / g, as shown in FIG. Figure 1As shown, the method for removing metal ions from hydrocarbon oil by electro-desalting cycle is carried out according to the following steps: In the first step, a hydrocarbon oil decalcifying agent (formic acid) and water are mixed (based on the weight of the super heavy oil, the mass contents of the hydrocarbon oil decalcifying agent and water are 1.8wt% and 20wt% respectively) to obtain a decalcifying agent aqueous solution; the decalcifying agent aqueous solution is mixed with a membrane reactor made of a metal membrane with a pore size of 50μm for super heavy oil at a temperature of 120°C and a pressure of 1MPa; the oil-water mixture is then placed in an electric desalting tank 3, and stays for 6 minutes at a temperature of 120°C and an electric field strength of 250V / cm, and then stays for 60 minutes at a temperature of 120°C and an electric field strength of 750V / cm. After oil and water separation, a demetalized hydrocarbon oil and a decalcifying agent aqueous solution after reaction are obtained (analysis shows that the calcium content in the demetalized hydrocarbon oil is 37.8μg / g, the magnesium content is 4.3μg / g, and the sodium content is 1.3μg / g; the calcium content in the decalcifying agent aqueous solution after reaction is 0.97wt% and the sodium content is 0.048wt%); In the second step, the decalcification agent aqueous solution after the reaction is pretreated by a microfiltration purification device 6 (composed of a two-stage microfiltration system with filtration accuracy of 5 μm and 0.2 μm, respectively, and the materials of the microfiltration membranes are polycarbonate and polyvinyl chloride, respectively) to remove suspended matter, sediment and other impurities therein, and the pretreated filtrate is sent to a nanofiltration device 8 (a primary nanofiltration and a secondary nanofiltration, both of which use a monovalent ion selective permeable nanofiltration membrane made of aromatic polyamide, the primary nanofiltration system uses a tubular nanofiltration membrane, and the secondary nanofiltration system uses a roll nanofiltration membrane) for treatment, and the treatment pressure is 2.0 MPa. , using a cross-flow filtration method to separate divalent calcium and magnesium ions from monovalent sodium ions, obtaining a sodium ion-containing filtrate and a concentrated solution of a reaction product of calcium ions and a decalcifying agent (the retention rates of calcium and magnesium ions are 98%, the retention rate of sodium ions is 5%; the recovery rate of the filtrate is 75%), and sending the obtained sodium ion-containing filtrate to a reverse osmosis device 11 (using a roll-type reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 6.0 MPa, and a fresh water and a first sodium ion-containing filtrate free of metal salts are obtained (the retention rate of sodium salts is 98%, and the recovery rate of fresh water is 85%). In the third step, in the solidification reaction tank 19, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration device is subjected to precipitation reaction with the phosphoric acid flowing out of the precipitant storage tank 18 (the amount of phosphoric acid used is the theoretical amount of phosphoric acid when the calcium ions in the concentrated solution of the reaction product of calcium ions and the decalcifying agent are completely reacted), the reaction temperature is 50°C, the time is 10 minutes, and a feed liquid containing calcium phosphate precipitates is generated; under the conditions of a temperature of 50°C and a pressure of 0.35 MPa, a first solid-liquid separator 22 (suction filtration) is used to perform a first solid-liquid separation to obtain a first recovered concentrated water and a calcium phosphate solid residue, and the first recovered concentrated water (phosphate content is 580 mg / L) is discharged to a high-temperature crystallization reaction tank 26, and a crystallization reaction is carried out in the high-temperature crystallization reaction tank 26, the reaction temperature is 100°C, the time is 30 minutes, and a feed liquid containing calcium phosphate crystals is generated, and under the conditions of a temperature of 100°C and a pressure of 0.35 MPa, a first solid-liquid separator 22 (suction filtration) is used to perform a first solid-liquid separation to obtain a first recovered concentrated water and a calcium phosphate solid residue, and the first recovered concentrated water (phosphate content is 580 mg / L) is discharged to a high-temperature crystallization reaction tank 26, and a crystallization reaction is carried out in the high-temperature crystallization reaction tank 26, the reaction temperature is 100°C, the time is 30 minutes, and a feed liquid containing calcium phosphate crystals is generated. Under the condition of 1.0MPa, a second solid-liquid separation is performed by a second solid-liquid separator 28 to obtain a second recovery concentrate (decalcification agent concentrate after decalcification) and calcium phosphate crystals, and the second recovery concentrate is discharged into a hydrocarbon oil decalcification agent aqueous solution tank 30; wherein the obtained calcium phosphate solid slag is washed, separated and dried to obtain a calcium phosphate product in the following specific steps: at room temperature, the calcium phosphate solid slag is washed with water in a calcium salt slag tank 23 (based on the weight of the calcium phosphate solid slag, the mass amount of water is 120wt%), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water is 7 and the washing is stopped; under the condition of a pressure of -0.1MPa, suction filtration is performed, and the separated calcium slag is dried in a drying device 24 at 190°C until the water content is less than or equal to 1wt%, to obtain a calcium phosphate product (the purity of calcium phosphate is 93.7wt%, meeting the quality standard of building gypsum); Step 4: In the evaporative condenser 14, the first sodium ion-containing filtrate is evaporated and concentrated at 120° C., and condensed at 35° C. to obtain a second sodium ion-containing filtrate and evaporated condensed water. The obtained second sodium ion-containing filtrate (the mass content of sodium salt is 13wt%, which meets the quality standard of brine drilling fluid) is placed in the brine storage tank 17; In the fifth step, the evaporated condensed water, the second recovered concentrated water (the decalcifying agent concentrated solution after decalcification) and the fresh water without metal salt are mixed in the hydrocarbon oil decalcifying agent aqueous solution tank 30 to obtain a recovered aqueous solution containing the hydrocarbon oil decalcifying agent (the phosphate content is 39 mg / L). When the concentration of the hydrocarbon oil decalcifying agent in the recovered aqueous solution is higher than the required ratio of the decalcifying agent to the hydrocarbon oil, a certain amount of water is added until the concentration of the hydrocarbon oil decalcifying agent in the aqueous solution meets the required ratio of the hydrocarbon oil decalcifying agent to the hydrocarbon oil, and then the solution is returned to the first step for recycling.

[0055] Example 20: The hydrocarbon oil to be treated in this example is super-heavy oil, and the metal ion contents are: calcium ion 2250 μg / g, magnesium ion 20.3 μg / g, sodium ion 94.1 μg / g, as shown in FIG. Figure 1As shown, the method for removing metal ions from hydrocarbon oil by electro-desalting cycle is carried out according to the following steps: In the first step, a hydrocarbon oil decalcifying agent (formic acid) and water are mixed (based on the weight of the super heavy oil, the mass contents of the hydrocarbon oil decalcifying agent and water are 5wt% and 6wt% respectively) to obtain a decalcifying agent aqueous solution; at 135° C., the decalcifying agent aqueous solution is mixed with a membrane reactor using a metal membrane with a pore size of 20 μm for super heavy oil as a material; then the oil-water mixture is placed in an electric desalting tank 3, and stays for 6 minutes at a temperature of 135° C. and an electric field strength of 250 V / cm, and then stays for 60 minutes at a temperature of 135° C. and an electric field strength of 750 V / cm, and after oil-water separation, a demetallized hydrocarbon oil and a decalcifying agent aqueous solution after reaction are obtained (the calcium content in the decalcifying agent aqueous solution after reaction is 1.11wt% and the sodium content is 0.046wt%); In the second step, the decalcification agent aqueous solution after the reaction is pretreated by a microfiltration purification device 6 (composed of a two-stage microfiltration system with filtration accuracies of 8 μm and 0.5 μm, respectively, and the materials of the microfiltration membranes are ceramic and polyvinyl chloride, respectively) to remove suspended matter, sediment and other impurities therein, and the pretreated filtrate is sent to a nanofiltration device 8 (a primary nanofiltration and a secondary nanofiltration, both of which use a monovalent ion selective permeable nanofiltration membrane made of aromatic polyamide, the primary nanofiltration system uses a tubular nanofiltration membrane, and the secondary nanofiltration system uses a roll nanofiltration membrane) for treatment, the treatment pressure is 2.0 MPa, and the The divalent calcium and magnesium ions are separated from the monovalent sodium ions by cross-flow filtration to obtain a sodium ion-containing filtrate and a concentrated solution of the reaction product of calcium ions and the decalcifying agent (the retention rates of calcium and magnesium ions are 95.3%, the retention rate of sodium ions is 5%; the recovery rate of the filtrate is 75%), and the obtained sodium ion-containing filtrate is sent to a reverse osmosis device 11 (using a roll reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 6.0 MPa to obtain a fresh water and a first sodium ion-containing filtrate free of metal salts (the retention rate of sodium salts is 90.5%, and the recovery rate of fresh water is 75%). In the third step, in the solidification reaction tank 19, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration device is subjected to precipitation reaction with the phosphoric acid flowing out of the precipitant storage tank 18 (the amount of phosphoric acid used is the theoretical amount of phosphoric acid when the calcium ions in the concentrated solution of the reaction product of calcium ions and the decalcifying agent are completely reacted), the reaction temperature is 50°C, the time is 25 minutes, and a feed liquid containing calcium phosphate precipitates is generated; under the conditions of a temperature of 50°C and a pressure of -0.1MPa, a first solid-liquid separator 22 (suction filtration) is used to perform a first solid-liquid separation to obtain a first recovered concentrated water and a calcium phosphate solid residue, and the first recovered concentrated water (phosphate content of 580mg / L) is discharged to a high-temperature crystallization reaction tank 26, and a crystallization reaction is carried out in the high-temperature crystallization reaction tank 26, the reaction temperature is 120°C, the time is 15 minutes, and a feed liquid containing calcium phosphate crystals is generated, and under the conditions of a temperature of 120°C and a pressure of 0. 1MPa, a second solid-liquid separator 28 (suction filtration) is used to perform a second solid-liquid separation to obtain a second recovered concentrate (decalcified decalcifying agent concentrate) and calcium phosphate crystals, and the second recovered concentrate is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank 30; wherein the obtained calcium phosphate solid slag is washed, separated and dried to obtain a calcium phosphate product in the following specific steps: at 40°C, the calcium phosphate solid slag is washed with water in a calcium salt slag tank 23 (based on the weight of the calcium phosphate solid slag, the mass amount of water is 120wt%), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water is 7 and the washing is stopped; suction filtration is performed under a pressure of -0.1MPa, and the separated calcium slag is dried in a drying device 24 at 190°C until the water mass content is less than or equal to 1wt%, to obtain a calcium phosphate product (the purity of calcium phosphate is 95.1wt%, meeting the quality standard of building gypsum); Step 4: In the evaporative condenser 14, the first sodium ion-containing filtrate is evaporated and concentrated at 120° C., and condensed at 50° C. to obtain a second sodium ion-containing filtrate and evaporated condensed water. The obtained second sodium ion-containing filtrate (the mass content of sodium salt is 13wt%, which meets the quality standard of brine drilling fluid) is placed in the brine storage tank 17; In the fifth step, the evaporated condensed water, the second recovered concentrated water (the decalcifying agent concentrated solution after decalcification) and the fresh water without metal salt are mixed in the hydrocarbon oil decalcifying agent aqueous solution tank 30 to obtain a recovered aqueous solution containing the hydrocarbon oil decalcifying agent (the phosphate content is 39 mg / L). When the concentration of the hydrocarbon oil decalcifying agent in the recovered aqueous solution is higher than the required ratio of the decalcifying agent to the hydrocarbon oil, a certain amount of water is added until the concentration of the hydrocarbon oil decalcifying agent in the aqueous solution meets the required ratio of the hydrocarbon oil decalcifying agent to the hydrocarbon oil, and then the solution is returned to the first step for recycling.

[0056] Example 21: Figure 1As shown, the hydrocarbon oil is treated for metal ion removal according to the method of Example 19, except that the primary nanofiltration system uses a tubular nanofiltration membrane made of cellulose acetate. Specifically, in the second step, the pre-treated filtrate is successively sent to the primary nanofiltration system and the secondary nanofiltration system for treatment, and the retention rate of calcium and magnesium ions is 90.1%, the retention rate of sodium ions is 2%, and the recovery rate of the filtrate is 78%. The obtained sodium ion-containing filtrate is sent to the reverse osmosis system for reverse osmosis treatment, and the retention rate of sodium salt is 97.5%, and the recovery rate of fresh water is 82%.

[0057] Example 22: Figure 1 As shown, the hydrocarbon oil is treated for metal ion removal according to the method of Example 19, except that the primary nanofiltration system uses a rolled nanofiltration membrane made of aromatic polyamide. Specifically, in the second step, the pre-treated filtrate is successively sent to the primary nanofiltration system and the secondary nanofiltration system for treatment, and the retention rate of calcium and magnesium ions is 87%, the retention rate of sodium ions is 1%, and the recovery rate of the filtrate is 80%. The obtained sodium ion-containing filtrate is sent to the reverse osmosis system for reverse osmosis treatment, and the retention rate of sodium salt is 98%, and the recovery rate of fresh water is 75%.

[0058] Example 23: Figure 1 As shown, the hydrocarbon oil is treated for metal ion removal according to the method of Example 19, except that the secondary nanofiltration system uses a roll nanofiltration membrane made of cellulose acetate. Specifically, in the second step, the pre-treated filtrate is successively sent to the primary nanofiltration system and the secondary nanofiltration system for treatment, and the retention rate of calcium and magnesium ions is 89%, the retention rate of sodium ions is 1%, and the recovery rate of the filtrate is 78%. The obtained sodium ion-containing filtrate is sent to the reverse osmosis system for reverse osmosis treatment, and the retention rate of sodium salt is 97%, and the recovery rate of fresh water is 80%.

[0059] Example 24: Figure 1 As shown, the hydrocarbon oil is treated for metal ion removal according to the method of Example 19, except that the secondary nanofiltration system uses a tubular nanofiltration membrane made of aromatic polyamide. Specifically, in the second step, the pre-treated filtrate is sequentially sent to the primary nanofiltration system and the secondary nanofiltration system for treatment, and the retention rate of calcium and magnesium ions is 80%, the retention rate of sodium ions is 0%, and the recovery rate of the filtrate is 85%. The obtained sodium ion-containing filtrate is sent to the reverse osmosis system for reverse osmosis treatment, and the retention rate of sodium salt is 97%, and the recovery rate of fresh water is 68%.

[0060] Example 25: Figure 1 As shown, the hydrocarbon oil was treated for metal ion removal according to the method of Example 19, except that a spiral reverse osmosis membrane made of sulfonated polysulfone was used for reverse osmosis treatment. Specifically, in the second step, the obtained sodium ion-containing filtrate was sent to a reverse osmosis system for reverse osmosis treatment, and the retention rate of sodium salt was 94.5%, and the fresh water recovery rate was 70%.

[0061] Example 26: Figure 1 As shown, the hydrocarbon oil was treated for metal ion removal according to the method of Example 19, except that a tubular reverse osmosis membrane made of polypiperazineamide was used for reverse osmosis treatment. Specifically, in the second step, the obtained sodium ion-containing filtrate was sent to a reverse osmosis system for reverse osmosis treatment, and the sodium salt rejection rate was 95%, and the fresh water recovery rate was 75%.

[0062] Comparative Example 1: The hydrocarbon oil was treated for metal ion removal according to the method of Example 12, except that the second step, the third step, the fourth step and the fifth step were not performed. The decalcification agent aqueous solution obtained in the first step was not subjected to the membrane separation in the second step. Since the reaction product of calcium ions and the decalcification agent was not concentrated, the calcium concentration in the decalcification agent aqueous solution after the reaction was too low to carry out the precipitation reaction, and the steps after the second step could not be carried out. The decalcification agent produced after the hydrocarbon oil was demetallized could not be recycled and reused, but could only be discharged, polluting the environment and causing waste.

[0063] Comparative Example 2: The hydrocarbon oil was treated with metal ions according to the method of Example 19, except that the second step was not performed. The decalcifying agent aqueous solution obtained in the first step was not subjected to membrane separation in the second step. Since the reaction product of calcium ions and the decalcifying agent was not concentrated, the calcium concentration in the decalcifying agent aqueous solution after the reaction was low. The device scale for the curing reaction in the third step was 4 times that of Example 19. Moreover, the sodium ion content in the hydrocarbon oil after the metal ion treatment after the 20th cycle reached 5.5 μg / g, and the sodium ion content in the hydrocarbon oil after the metal ion treatment after the 40th cycle reached 11.3 μg / g. The sodium ion content in the hydrocarbon oil after the metal ion treatment exceeded the processing requirement that the salt content after the hydrocarbon oil pretreatment was not more than 5 μg / g. The decalcifying agent aqueous solution after the reaction could only be discharged for treatment, and it was not possible to achieve the recycling of the hydrocarbon oil decalcifying agent and the resource utilization of the hydrocarbon oil decalcification wastewater.

[0064] The recovered aqueous solution containing hydrocarbon oil decalcifying agent (i.e., decalcifying agent aqueous solution) obtained in Examples 12 to 26 was circulated for hydrocarbon oil metal ion removal treatment. The metal ion content in the hydrocarbon oil after metal ion removal treatment, the decalcifying agent content in the recovered aqueous solution containing hydrocarbon oil decalcifying agent, and the water replenishment conditions are shown in Table 1, wherein " / " in Table 1 represents that the corresponding index does not need to be analyzed.

[0065] Examples 12 to 20 respectively carry out metal ion removal treatment on hydrocarbon oils with different metal ion contents. As can be seen from Table 1, for hydrocarbon oils with different metal ion contents, the method of the present invention is used to carry out metal ion removal treatment on hydrocarbon oils. After the recovered aqueous solution containing the decalcifying agent is recycled for 40 times, the removal effect of metal ions in the hydrocarbon oil is still equivalent to the removal effect of the 0th cycle (that is, the fresh hydrocarbon oil decalcifying agent aqueous solution), indicating that the method and device for cyclic demetallization of hydrocarbon oil electro-desalting of the present invention can well realize the recycling of hydrocarbon oil decalcifying agent and resource utilization of decalcification wastewater.

[0066] However, the decalcification agent aqueous solution obtained after the reaction in Comparative Example 2 is not subjected to membrane separation, which not only significantly increases the scale of the device required for the solidification reaction, but also significantly increases the sodium ion content in the hydrocarbon oil after the metal ion removal treatment as the number of cycles increases. When the number of cycles increases to 20 times, the sodium ion content in the hydrocarbon oil after the metal ion removal treatment is 5.5 μg / g, and the sodium chloride content in the hydrocarbon oil is unqualified (usually, the sodium chloride content in the hydrocarbon oil is required to be less than 5 mg Nacl / L after electrical desalting, and if it is greater than 5 mg Nacl / L, the crude oil electrical desalting is judged to be unqualified), and the hydrocarbon oil decalcification wastewater can only be discharged, and the recycling and resource utilization of the hydrocarbon oil decalcification agent cannot be well realized.

[0067] In addition, Examples 21 to 24 respectively change the material and form of the nanofiltration membrane in the primary nanofiltration system and the secondary nanofiltration system. Compared with Example 19, the retention rate of calcium and magnesium ions in the nanofiltration system in Examples 21 to 24 is reduced, the recovery rate of the nanofiltration filtrate is increased, the fresh water recovery rate of the reverse osmosis system is reduced, and the amount of water replenishment during the circulation process is increased, indicating that the retention rate of calcium and magnesium ions in the nanofiltration system is reduced, and more calcium and magnesium ions enter the reverse osmosis system, increasing the processing load of the reverse osmosis membrane. These calcium and magnesium ions eventually enter the fourth and fifth steps. There is a risk of equipment scaling in the fourth and fifth steps, which reduces the evaporation amount and increases the difficulty of processing. Examples 25 and 26 respectively change the material and form of the reverse osmosis membrane in the reverse osmosis system. Compared with Example 19, the fresh water recovery rate of the reverse osmosis system in Examples 25 and 26 is reduced, indicating that the material and form of the reverse osmosis membrane in the reverse osmosis system are changed, so that the amount of reverse osmosis concentrated water is increased, and the processing load of the fourth and fifth steps is increased.

[0068] In summary, the present invention reduces the processing volume of subsequent solidification and regeneration, realizing the miniaturization of industrial equipment, and on the other hand, converts the metal ions removed from hydrocarbon oil into resources and makes resource utilization of hydrocarbon oil decalcification wastewater, thereby realizing low-carbon emissions, green environmental protection and circular economy.

[0069] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A method for removing metal ions by electro-desalting of hydrocarbon oil, characterized in that The process is carried out according to the following steps: first, a required amount of hydrocarbon oil is mixed with a decalcifying agent aqueous solution and then subjected to an electrical desalting treatment to obtain a demetallized hydrocarbon oil and a reacted decalcifying agent aqueous solution; second, the reacted decalcifying agent aqueous solution is subjected to membrane separation to obtain a concentrated solution of a reaction product of calcium ions and the decalcifying agent, a first sodium ion-containing filtrate and fresh water respectively; third, the concentrated solution of the reaction product of calcium ions and the decalcifying agent is subjected to a decalcification treatment to obtain a decalcified decalcifying agent concentrated solution; fourth, the first sodium ion-containing filtrate is evaporated and condensed to obtain a second sodium ion-containing filtrate and condensed water; fifth, the decalcified decalcifying agent concentrated solution, fresh water and condensed water are mixed to obtain a decalcifying agent aqueous solution, which is returned to the first step for recycling.

2. The method for removing metal ions by hydrocarbon oil electro-desalting cycle according to claim 1, characterized in that In the first step, the specific process of the electric desalting treatment is as follows: first, at a temperature of 50°C to 150°C and a pressure of 0.02MPa to 1.0MPa, a required amount of hydrocarbon oil and a decalcifying agent aqueous solution are mixed to obtain a mixed solution; then, the mixed solution is treated for 1min to 60min under an electric field strength of 50V / cm to 500V / cm, and then treated for 5min to 200min under an electric field strength of 500V / cm to 1500V / cm, to obtain demetallized hydrocarbon oil and a reacted decalcifying agent aqueous solution, respectively, wherein the mass content of the decalcifying agent in the mixed solution is 0.01wt% to 5wt%, the mass content of water is 1% to 25%, and the rest is hydrocarbon oil, and the decalcifying agent is one or more of formic acid, acetic acid, propionic acid and butyric acid.

3. The method for removing metal ions by hydrocarbon oil electro-desalting cycle according to claim 1 or 2, characterized in that In the third step, the specific process of the decalcification treatment is as follows: first, the concentrated solution of the reaction product of calcium ions and the decalcification agent is mixed with a required amount of a precipitant to perform a precipitation reaction to obtain a precipitation reaction product; second, the precipitation reaction product is subjected to a first solid-liquid separation to obtain a liquid phase product and a solid phase product respectively; Then, the solid phase product is washed, separated and dried to obtain a calcium salt product, and the liquid phase product is subjected to a high temperature crystallization reaction to obtain a high temperature crystallization reactant; finally, the high temperature crystallization reactant is subjected to a second solid-liquid separation to obtain a decalcified decalcification agent concentrate.

4. The method for removing metal ions by hydrocarbon oil electro-desalting cycle according to claim 3, characterized in that The precipitant is sulfuric acid or phosphoric acid, the precipitation reaction temperature is 20°C to 50°C, the reaction time is 5min to 30min, the high temperature crystallization reaction temperature is 100°C to 150°C, and the reaction time is 5min to 30min.

5. The method for cyclically removing metal ions from hydrocarbon oil by electro-desalting according to any one of claims 1 to 4, characterized in that In the second step, the specific process of membrane separation treatment includes: first, passing the decalcifying agent aqueous solution after the reaction through a nanofiltration membrane for at least one stage of nanofiltration treatment to obtain a concentrated solution and a filtrate of the reaction product of calcium ions and the decalcifying agent; then, passing the filtrate through a reverse osmosis membrane for at least one stage of reverse osmosis treatment to obtain a first sodium ion-containing filtrate and fresh water.

6. The method for removing metal ions by hydrocarbon oil electro-desalting cycle according to claim 5, characterized in that After the reaction, the decalcification agent aqueous solution is subjected to two-stage nanofiltration treatment through a nanofiltration membrane, and the filtrate is subjected to one-stage reverse osmosis treatment through a reverse osmosis membrane, wherein the pressure of the nanofiltration treatment is 0.2 MPa to 2.0 MPa, the nanofiltration membrane is a monovalent ion selective permeable nanofiltration membrane, the material of the nanofiltration membrane is one or more of aromatic polyamide, polypiperazineamide, cellulose acetate and sulfonated polyether sulfone, the pressure of the reverse osmosis treatment is 2.0 MPa to 6.0 MPa, and the material of the reverse osmosis membrane is one or more of aromatic polyamide, polypiperazineamide, polyimide and sulfonated polysulfone.

7. The method for removing metal ions by hydrocarbon oil electro-desalting cycle according to claim 5 or 6, characterized in that The specific process of membrane separation treatment also includes: pre-treating the aqueous solution of the decalcifying agent after the reaction, and then performing nanofiltration treatment, wherein the pre-treatment is to perform microfiltration treatment on the aqueous solution of the decalcifying agent after the reaction through a microfiltration membrane, and the material of the microfiltration membrane is one or more of ceramic, polypropylene, polycarbonate, polyvinyl chloride, polysulfone, polyvinylidene fluoride and polytetrafluoroethylene.

8. The method for removing metal ions by electro-desalting hydrocarbon oil according to any one of claims 1 to 7, characterized in that In the fourth step, the evaporation temperature is 120° C. to 200° C., the condensation temperature is 20° C. to 50° C., and the mass content of the metallic sodium salt in the obtained second sodium ion-containing filtrate is 10% to 30%.

9. A device for implementing the method for cyclic demetallation of hydrocarbon oil electro-desalting according to any one of claims 1 to 8, characterized in that The invention comprises a hydrocarbon oil storage tank, a mixer, an electric desalting tank, a microfiltration purification device, a nanofiltration device, a reverse osmosis device, an evaporative condenser, a brine storage tank, a precipitant storage tank, a solidification reaction tank, a first solid-liquid separator, a high-temperature crystallization reaction tank, a second solid-liquid separator, and a hydrocarbon oil decalcifying agent aqueous solution tank. A mixed liquid inlet pipeline is fixedly connected between the hydrocarbon oil storage tank outlet and the mixer inlet, a mixed liquid outlet pipeline is fixedly connected between the mixer outlet and the electric desalting tank inlet, a post-reaction decalcifying agent aqueous solution inlet pipeline is fixedly connected between the first outlet of the electric desalting tank and the microfiltration purification device inlet, a pre-treated filtrate pipeline is fixedly connected between the microfiltration purification device outlet and the nanofiltration device inlet, a sodium ion filtrate pipeline is fixedly connected between the first outlet of the nanofiltration device and the reverse osmosis device inlet, a first sodium ion filtrate pipeline is fixedly connected between the first outlet of the reverse osmosis device and the evaporative condenser inlet, and a first outlet of the evaporative condenser and the brine storage tank inlet are connected. A second sodium ion filtrate pipeline is fixedly connected between the second outlet of the evaporative condenser and the first inlet of the hydrocarbon oil decalcifying agent aqueous solution tank, an evaporative condensate delivery pipeline is fixedly connected between the second outlet of the nanofiltration device and the first inlet of the solidification reaction tank, a material liquid delivery pipeline is fixedly connected between the outlet of the solidification reaction tank and the inlet of the first solid-liquid separator, a first concentrated water recovery pipeline is fixedly connected between the first outlet of the first solid-liquid separator and the inlet of the high-temperature crystallization reaction tank, a material delivery pipeline is fixedly connected between the outlet of the high-temperature crystallization reaction tank and the inlet of the second solid-liquid separator, a second concentrated water recovery pipeline is fixedly connected between the first outlet of the second solid-liquid separator and the second inlet of the hydrocarbon oil decalcifying agent aqueous solution tank, a recovered solution pipeline is fixedly connected between the outlet of the hydrocarbon oil decalcifying agent aqueous solution tank and the mixed liquid inlet pipeline, and a precipitant delivery pipeline is fixedly connected between the outlet of the precipitant storage tank and the second inlet of the solidification reaction tank.

10. The device according to claim 9, characterized in that It also includes a calcium salt slag tank and a drying device. A first calcium salt pipeline is fixedly connected between the first solid-liquid separator outlet and the first inlet of the calcium salt slag tank, a second calcium salt pipeline is fixedly connected between the second solid-liquid separator outlet and the second inlet of the calcium salt slag tank, a solid phase drying pipeline is fixedly connected between the calcium salt slag tank outlet and the inlet of the drying device, a calcium sulfate product pipeline is fixedly connected to the outlet of the drying device, a demetallized hydrocarbon oil output pipeline is fixedly connected to the second outlet of the electric desalting tank, a fresh water delivery pipeline is fixedly connected between the second outlet of the reverse osmosis device and the evaporation condensate delivery pipeline, and a water injection pipeline is fixedly connected to the third inlet of the salt slag tank and the third inlet of the hydrocarbon oil decalcification agent aqueous solution tank.

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