Method for removing metal ions from hydrocarbon oil and device for removing metal ions from hydrocarbon oil

Abstract

The invention relates to the field of petroleum processing wastewater treatment, and discloses a method for removing metal ions from hydrocarbon oil and a device for removing metal ions from hydrocarbon oil. The method comprises the following steps: S1, carrying out electro-desalting treatment on hydrocarbon oil and a decalcifying agent aqueous solution to obtain demetallized hydrocarbon oil and a reacted decalcifying agent aqueous solution; s2, carrying out membrane separation on the reacted aqueous solution of the decalcifying agent to obtain a reaction product concentrated solution of calcium ions and the decalcifying agent, a first concentrated solution containing sodium ions and fresh water; s3, performing decalcification treatment on the reaction product concentrated solution of the calcium ions and the decalcification agent to obtain a decalcified decalcification agent concentrated solution; s4, evaporating and condensing the first concentrated solution containing sodium ions to obtain a second concentrated solution containing sodium ions and condensed water; and mixing the decalcification agent concentrated solution after decalcification, the fresh water and the condensed water, and returning to S1. According to the method, recycling of the hydrocarbon oil decalcifying agent, cyclic decalcification of the hydrocarbon oil and resource utilization of the hydrocarbon oil decalcification wastewater are realized.

Description

Technical Field

[0001] The invention relates to the field of petroleum processing wastewater treatment, and in particular to a method and a device for removing metal ions from hydrocarbon oil. Background Art

[0002] As crude oil resources become heavier, the metal ion content in crude oil is on the rise. The presence of high concentrations of metal ions such as calcium and magnesium has largely limited the further improvement of crude oil processing depth. The commonly used method is to add chemical agents such as decalcifying agents during the electrical desalting and dehydration process of crude oil to achieve the purpose of increasing the removal rate of metallic calcium. However, the introduction of chemical agents causes a certain degree of change in the water quality of the electrical desalting wastewater produced during the demetallization process. How to efficiently treat the electrical desalting wastewater has always been a technical bottleneck restricting the industrialization of the decalcification process.

[0003] CN86107286A, CN1036981A, CN1267707A, CN87105863A, CN1657596A, CN1431277A, CN1554967A, CN1982413A, CN101085932A and CN101067012A disclose hydrocarbon oil demetallization processes using a one-time decalcifying agent, which have the advantages of obvious removal effect and simple operation for hydrocarbon oil demetallization. However, the industrial wastewater generated in the demetallization process has the defect of serious environmental pollution. If it is incorporated into the refinery sewage treatment system, it may even lead to unreasonable external drainage.

[0004] CN1202208C discloses a hydrocarbon oil demetallization cycle method, which utilizes the cycle to remove metal calcium in hydrocarbon oil, so that hydrocarbon oil decalcification agent can be recycled, thereby reducing the consumption cost of hydrocarbon oil decalcification agent. However, it also brings about the circulation of desalinated water, which affects the normal operation of the electric desalination device, and the problem of scaling of pipelines or reactors often exists during industrial implementation. In addition, this technology has strict control requirements on the amount of precipitant to avoid corrosion of the device, poor water quality of external drainage, and increased operating pressure of subsequent sewage treatment devices.

[0005] CN105733664A discloses a series of treatments for organic acid calcium wastewater. When the calcium ion concentration in the wastewater from crude oil electric desalination 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] CN102399581A discloses using ion exchange resin to replace the decalcifying agent, and regenerating the resin after demetallization by acid treatment. However, there are problems such as short service life of the resin and difficulty in engineering.

[0007] Therefore, there is an urgent need for a hydrocarbon oil metal ion removal process that can process metals in crude oil, recycle wastewater, waste residue and decalcifying agents, and achieve miniaturization and cleanliness of the equipment. Summary of the invention

[0008] The purpose of the present invention is to overcome the problem of high pollution emission in the process of hydrocarbon oil decalcification in the prior art, and to provide a method and device for removing metal ions from hydrocarbon oil. The method converts the metal ions removed from the hydrocarbon oil into resources while realizing the recycling of hydrocarbon oil demetallization, and makes the waste water of hydrocarbon oil decalcification resource-utilized, thus realizing low carbon emission, green environmental protection and circular economy.

[0009] In order to achieve the above object, the present invention provides a method for removing metal ions from hydrocarbon oil in a first aspect, wherein the method comprises the following steps:

[0010] S1, subjecting the hydrocarbon oil and the decalcifying agent aqueous solution to an electrical desalting treatment to obtain a demetallized hydrocarbon oil and a reacted decalcifying agent aqueous solution;

[0011] S2, subjecting the decalcifying agent aqueous solution after the reaction to membrane separation to obtain a concentrated solution of the reaction product of calcium ions and the decalcifying agent, a first concentrated solution containing sodium ions, and fresh water;

[0012] S3, decalcifying the concentrated solution of the reaction product of the calcium ions and the decalcifying agent to obtain a decalcified concentrated solution of the decalcifying agent;

[0013] S4, evaporating and condensing the first sodium ion-containing concentrated solution to obtain a second sodium ion-containing concentrated solution and condensed water; mixing the decalcified decalcifying agent concentrated solution, the fresh water and the condensed water and returning the mixture to S1.

[0014] A second aspect of the present invention provides a device for removing metal ions from hydrocarbon oil, wherein the device comprises:

[0015] An electrical desalting unit, used for conducting electrical desalting treatment on hydrocarbon oil and decalcifying agent aqueous solution to remove metal ions in the hydrocarbon oil;

[0016] A membrane separation unit, used for performing membrane separation on the water phase flowing out of the electrical desalination unit;

[0017] an evaporation and condensation unit, used for evaporating and concentrating the sodium ion-containing concentrated liquid flowing out of the membrane separation unit, and condensing the obtained gas phase product into condensed water;

[0018] The decalcification treatment unit is used to decalcify the concentrated solution of the reaction product of calcium ions and decalcification agent flowing out of the membrane separation unit, and mix the obtained liquid phase product, the fresh water flowing out of the membrane separation unit and the condensed water flowing out of the evaporation and condensation unit and return them to the electrical desalination unit.

[0019] Through the above technical solution, the beneficial effects of the present invention are:

[0020] The present invention performs membrane separation on the decalcifying agent aqueous solution obtained by the electro-desalting treatment, and concentrates the decalcifying agent aqueous solution to a certain concentration, thereby reducing the processing capacity of subsequent solidification (precipitation) regeneration and other processing equipment, and realizing miniaturization of industrial equipment. The present invention utilizes the process of cyclically removing calcium ions from hydrocarbon oil, effectively overcoming the disadvantages of high COD emission and high decalcification cost in the traditional hydrocarbon oil decalcification method that the hydrocarbon oil decalcifying agent is discharged with the desalted water after one-time use, so that the hydrocarbon oil decalcifying agent and the electro-desalting wastewater can be cyclically used. At the same time, the present invention converts the metal ions removed from the hydrocarbon oil into corresponding salts, and can also recycle the removed metal calcium salts, barium salts and sodium salts, and the quality of the obtained metal salt products can reach the level of qualified products or above, so that the removed metal salt slag resources are effectively utilized, and the hydrocarbon oil decalcifying agent and hydrocarbon oil decalcification wastewater are resource-utilized, so that the hydrocarbon oil demetallization cost is greatly reduced to below 80%, and COD emission is reduced by 100%. Therefore, the present invention has the advantages of turning waste into treasure, zero discharge of wastewater and waste residue, and being environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a flow chart of a method for removing metal ions from hydrocarbon oil in a specific embodiment of the present invention.

[0022] Description of Reference Numerals

[0023] 1 Hydrocarbon oil 2 Mixer 3 Electric desalting tank 4 Demetallized hydrocarbon oil

[0024] 5. Decalcification agent aqueous solution after reaction 6. Microfiltration purification system

[0025] 7 Filtrate after pretreatment 8 Nanofiltration system 9 Concentrated solution of the reaction product of calcium ions and decalcification agent

[0026] 10 Filtrate containing sodium ions 11 Reverse osmosis system 12 Fresh water without metal salts

[0027] 13 first sodium ion-containing concentrated liquid 14 evaporation condensation unit

[0028] 15 second sodium ion concentrated liquid 16 evaporated condensed water 17 brine storage tank

[0029] 18 first precipitant storage tank 19 second precipitant storage tank 20 first solidification reaction tank

[0030] 21 Liquid containing calcium sulfate precipitation 22 First solid-liquid separator

[0031] 23 First concentrated water recovery 24 Calcium salt slag tank 25 First drying system

[0032] 26 Calcium sulfate product 27 Second solidification reaction tank 28 Feed liquid containing barium sulfate precipitation

[0033] 29 Second solid-liquid separator 30 Barium salt slag tank 31 Second drying system

[0034] 32 Barium sulfate product 33 Second recovery concentrated water 34 Hydrocarbon oil decalcification agent aqueous solution tank

[0035] 35 Recovery aqueous solution of hydrocarbon oil decalcifying agent 36 Water DETAILED DESCRIPTION

[0036] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0037] The first aspect of the present invention provides a method for removing metal ions from hydrocarbon oil, wherein the method comprises the following steps:

[0038] S1, subjecting the hydrocarbon oil and the decalcifying agent aqueous solution to an electrical desalting treatment to obtain a demetallized hydrocarbon oil and a reacted decalcifying agent aqueous solution;

[0039] S2, subjecting the decalcifying agent aqueous solution after the reaction to membrane separation to obtain a concentrated solution of the reaction product of calcium ions and the decalcifying agent, a first concentrated solution containing sodium ions, and fresh water;

[0040] S3, decalcifying the concentrated solution of the reaction product of the calcium ions and the decalcifying agent to obtain a decalcified concentrated solution of the decalcifying agent;

[0041] S4, evaporating and condensing the first sodium ion-containing concentrated solution to obtain a second sodium ion-containing concentrated solution and condensed water; mixing the decalcified decalcifying agent concentrated solution, the fresh water and the condensed water and returning the mixture to S1.

[0042] The method provided by the present invention can be used to remove metal ions from various hydrocarbon oils. For example, the hydrocarbon oil can be a reduced-four fraction oil with metal ion contents of 40.4 μg / g calcium ion, 5.13 μg / g magnesium ion, and 2.8 μg / g sodium ion; it can be a crude oil with metal ion contents of 520 μg / g calcium ion, 5.64 μg / g magnesium ion, and 120.1 μg / g sodium ion; it can be a heavy oil with metal ion contents of 712 μg / g calcium ion, 2.53 μg / g magnesium ion, and 95.8 μg / g sodium ion; it can be an extra-heavy oil with metal ion contents of 1380 μg / g calcium ion, 14.32 μg / g magnesium ion, and 282 μg / g sodium ion; it can be a metal ion content of 27.3 μg / g calcium ion, 27.3 μg / g magnesium ion, and 27.3 μg / g sodium ion. / g, magnesium ion 0.32μg / g, sodium ion 0.8μg / g of dirty oil; it can be crude oil with metal ion contents of calcium ion 208μg / g, magnesium ion 3.14μg / g, sodium ion 41.7μg / g; it can be residual oil with metal ion contents of calcium ion 1469μg / g, magnesium ion 4.3μg / g, sodium ion 123.5μg / g; it can be extra heavy oil with metal ion contents of calcium ion 1980μg / g, magnesium ion 23.7μg / g, sodium ion 98.1μg / g; it can be extra heavy oil with metal ion contents of calcium ion 2250μg / g, magnesium ion 20.3μg / g, sodium ion 94.1μg / g.

[0043] After the hydrocarbon oil decalcifying agent aqueous solution is fully mixed with the hydrocarbon oil, an electric desalting process is performed, and the metal ions in the hydrocarbon oil enter the decalcifying agent aqueous solution to obtain 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 concentrated solution of a reaction product 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 concentrated solution of a reaction product of calcium ions and the decalcifying agent), a first concentrated solution containing sodium ions and fresh water without metal salts; the first concentrated solution containing sodium ions is further evaporated, concentrated and condensed to obtain a second concentrated solution containing sodium ions and evaporated condensed water; the concentrated solution of the reaction product of calcium ions and the decalcifying agent is decalcified, mixed with fresh water without metal salts 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 decalcification of hydrocarbon oil and the resource utilization of hydrocarbon oil decalcification wastewater.

[0044] According to the present invention, preferably, in S3, the decalcification method comprises: mixing the concentrated solution of the reaction product of the calcium ions and the decalcifying agent with a first precipitant to perform a first precipitation reaction, and then performing a first solid-liquid separation; mixing the obtained liquid phase product with a second precipitant to perform a second precipitation reaction, and performing a second solid-liquid separation to obtain the decalcified decalcifying agent concentrated solution.

[0045] According to the present invention, preferably, the conditions for the first solid-liquid separation include: a temperature of 20-50° C. and a pressure of -0.1 MPa to 1 MPa.

[0046] According to the present invention, preferably, the first precipitant is sulfuric acid or phosphoric acid.

[0047] In the present invention, the dosage of the first precipitant is the theoretical dosage of the first precipitant when the first precipitant completely reacts with the calcium ions in the concentrated solution of the reaction product of the calcium ions and the decalcifying agent.

[0048] According to the present invention, preferably, the temperature of the first precipitation reaction is 20-50° C. and the time is 5-30 min.

[0049] According to the present invention, preferably, the conditions for the second solid-liquid separation include: a temperature of 20-50° C. and a pressure of -0.1 MPa to 1 MPa.

[0050] According to the present invention, preferably, the second precipitant is barium chloride, barium hydroxide or barium acetate.

[0051] In the present invention, the dosage of the second precipitant is the theoretical dosage of the second precipitant when the second precipitant completely reacts with the sulfate or phosphate contained in the liquid phase product obtained by the first precipitation reaction.

[0052] When the first precipitant is sulfuric acid or phosphoric acid, and the second precipitant is barium chloride, barium hydroxide or barium acetate, the concentrated solution of the reaction product of the calcium ions and the decalcifying agent is mixed with sulfuric acid (or phosphoric acid) to carry out a first precipitation reaction, sulfuric acid (or phosphoric acid) reacts with calcium to form a supersaturated solution of calcium sulfate (or calcium phosphate), and the calcium sulfate (or calcium phosphate) precipitates in a solid form, and solid calcium sulfate particles or solid calcium phosphate particles are obtained through a first solid-liquid separation, and a part of the dissolved calcium sulfate (or calcium phosphate) is dissolved in the liquid phase product obtained through the first solid-liquid separation in the form of calcium ions and sulfate ions (or phosphate ions); the liquid phase product obtained through the first solid-liquid separation is mixed with barium chloride, barium hydroxide or barium acetate to carry out a second precipitation reaction, and the barium ions react with the sulfate ions (or phosphate ions) contained in the liquid phase product, and solid barium sulfate particles or solid barium phosphate particles are obtained through a second solid-liquid separation, while the calcium ions continue to dissolve in the liquid phase product obtained through the second solid-liquid separation in the form of ions.

[0053] According to the present invention, preferably, the temperature of the second precipitation reaction is 20-50° C. and the time is 5-30 min.

[0054] In the present invention, the solid-liquid separation can be carried out after static sedimentation, after centrifugation, or by using a filter.

[0055] According to the present invention, preferably, in S1, based on the weight of the hydrocarbon oil, the contents of the decalcifying agent and water in the decalcifying agent aqueous solution are 0.01-5wt% and 1-25wt%, respectively.

[0056] When the concentration of hydrocarbon oil decalcifying agent in the aqueous solution formed by mixing the decalcified decalcifying agent concentrate, the fresh water and the condensed water 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.

[0057] According to the present invention, preferably, the decalcifying agent is selected from at least one of formic acid, acetic acid, propionic acid and butyric acid.

[0058] According to the present invention, preferably, the process of the electrical desalination treatment comprises: mixing the hydrocarbon oil and the decalcifying agent aqueous solution at a temperature of 50-150°C and a pressure of 0.02-1MPa, controlling the diameter of the oil and water particles to be within the range of 0.1-50μm; then staying for 1-60min under an electric field strength of 50-500V / cm, and then staying for 5-200min under an electric field strength of 500-1500V / cm.

[0059] According to the present invention, preferably, in S2, the membrane separation process comprises: subjecting the decalcifying agent aqueous solution after the reaction to at least one stage of nanofiltration treatment through a nanofiltration membrane to obtain a concentrated solution and a filtrate of the reaction product of the calcium ions and the decalcifying agent, and then subjecting the filtrate to at least one stage of reverse osmosis treatment through a reverse osmosis membrane to obtain the first sodium ion-containing concentrated solution and the fresh water.

[0060] After nanofiltration treatment, the compound formed after the reaction of calcium ions and the decalcifying agent is retained by the nanofiltration membrane to form a concentrated solution of the reaction product of calcium ions and the decalcifying agent; sodium ions and water selectively pass through the nanofiltration membrane to form a filtrate containing sodium ions.

[0061] According to the present invention, preferably, the pressure of the nanofiltration treatment is 0.2-2MPa. When the pressure of the nanofiltration treatment meets 0.2-2MPa, the nanofiltration treatment is performed by cross-flow filtration, and the recovery rate of the filtrate is 50-85%. 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 as the calcium ion concentration increases.

[0062] According to the present invention, preferably, the nanofiltration membrane is selected from a monovalent ion selective permeable nanofiltration membrane, and its retention rate for calcium and magnesium ions is 95-99%, and its retention rate for sodium ions is 1-10%.

[0063] According to the present invention, preferably, 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.

[0064] According to the present invention, preferably, the material of the nanofiltration membrane is selected from at least one of aromatic polyamide, polypiperazineamide, cellulose acetate and sulfonated polyethersulfone, preferably aromatic polyamide.

[0065] According to the present invention, a reverse osmosis pressure greater than the osmotic pressure of the filtrate is used for reverse osmosis treatment, preferably, the pressure of the reverse osmosis treatment is 2-6MPa. When the pressure of the reverse osmosis treatment meets 2-6MPa, a single-stage reverse osmosis treatment is performed by cross-flow filtration, and the retention rate of sodium salt reaches 97-98%, and the fresh water recovery rate is 75-85%.

[0066] According to the present invention, preferably, the reverse osmosis membrane is a plate reverse osmosis membrane, a tubular reverse osmosis membrane or a spiral reverse osmosis membrane, preferably a spiral reverse osmosis membrane.

[0067] According to the present invention, preferably, the material of the reverse osmosis membrane is selected from at least one of aromatic polyamide, polypiperazineamide, polyimide and sulfonated polysulfone, preferably polypiperazineamide.

[0068] According to a preferred embodiment of the present invention, the decalcification agent aqueous solution after the reaction is subjected to two-stage nanofiltration treatment, and the filtrate is subjected to primary reverse osmosis treatment. Among them, a tubular nanofiltration membrane made of aromatic polyamide is used for primary nanofiltration treatment, a rolled nanofiltration membrane made of aromatic polyamide is used for secondary nanofiltration treatment; and a rolled reverse osmosis membrane made of polypiperazineamide is used for reverse osmosis treatment.

[0069] For calcium-containing hydrocarbon oils 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. The inventors found that 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 both of the two-stage nanofiltration treatments 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 by 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, eliminate the influence of water-soluble sodium salts on the electrical desalting of crude oil, achieve complete regeneration of decalcified wastewater and perform long-term recycling, and can well achieve resource utilization of decalcified wastewater.

[0070] According to the present invention, preferably, the membrane separation process further comprises: pre-treating the decalcifying agent aqueous solution after the reaction, and then performing the nanofiltration treatment. The purpose of the pre-treatment is to remove suspended matter, silt and other impurities in the decalcifying agent aqueous solution after the reaction.

[0071] According to the present invention, preferably, the pretreatment method comprises: subjecting the reacted decalcifying agent aqueous solution to microfiltration treatment through a microfiltration membrane.

[0072] According to the present invention, preferably, the microfiltration membrane is selected from one or two of the average pore size (filtration accuracy) of 0.1-0.5 μm, 0.5-1 μm, 1-5 μm and 5-10 μm, and the microfiltration purification system can be a combination of microfiltration membranes with different average pore sizes.

[0073] According to the present invention, preferably, the material of the microfiltration membrane is selected from at least one of ceramics, polypropylene, polycarbonate, polyvinyl chloride, polysulfone, polyvinylidene fluoride and polytetrafluoroethylene.

[0074] According to the present invention, preferably, in S4, the evaporation temperature is 120-200°C, and the condensation temperature is 20-50°C.

[0075] According to the present invention, preferably, the content of sodium salt in the second sodium ion-containing concentrate is 10-30wt%. The second sodium ion-containing concentrate with a sodium salt content of 10-30wt% can be used as a drilling fluid product.

[0076] According to the present invention, preferably, the method further comprises: washing, slagging and drying the solid phase product obtained by the first precipitation reaction to obtain a calcium salt product. The specific steps are:

[0077] At 20-50° C., the solid phase product (calcium salt slag) obtained by the first precipitation reaction is washed with water until the pH value of the washed water is 6-7, and the washing is stopped; then the slag is separated by static sedimentation, centrifugation or using a filter at 20-50° C. and -0.1 MPa to 1 MPa, and then dried at 100-200° C. to a moisture content of less than or equal to 1wt%, thereby obtaining a calcium salt product.

[0078] According to the present invention, preferably, the method further comprises: washing, slagging and drying the solid phase product obtained by the second precipitation reaction to obtain a barium salt product. The specific steps are:

[0079] At 20-50° C., the solid phase product (barium salt slag) obtained by the second precipitation reaction is washed with water until the pH value of the washed water is 6-7, and the washing is stopped; then the slag is separated by static sedimentation, centrifugation or use of a filter at 20-50° C. and -0.1 MPa to 1 MPa, and then dried at 100-200° C. to a moisture content of less than or equal to 1wt%, thereby obtaining a barium salt product.

[0080] A second aspect of the present invention provides a device for removing metal ions from hydrocarbon oil, wherein the device comprises:

[0081] An electrical desalting unit, used for conducting electrical desalting treatment on hydrocarbon oil and decalcifying agent aqueous solution to remove metal ions in the hydrocarbon oil;

[0082] A membrane separation unit, used for performing membrane separation on the water phase flowing out of the electrical desalination unit;

[0083] an evaporation and condensation unit, used for evaporating and concentrating the sodium ion-containing concentrated liquid flowing out of the membrane separation unit, and condensing the obtained gas phase product into condensed water;

[0084] The decalcification treatment unit is used to decalcify the concentrated solution of the reaction product of calcium ions and decalcification agent flowing out of the membrane separation unit, and mix the obtained liquid phase product, the fresh water flowing out of the membrane separation unit and the condensed water flowing out of the evaporation and condensation unit and return them to the electrical desalination unit.

[0085] According to the present invention, preferably, the electric desalination unit comprises a mixer and an electric desalination tank which are connected. Preferably, the mixer is a mixing valve, a static mixer or an ultrasonic mixer.

[0086] According to the present invention, preferably, the membrane separation unit comprises: a nanofiltration system for subjecting the aqueous phase flowing out of the electrical desalination unit to nanofiltration treatment; and a reverse osmosis system for subjecting the filtrate flowing out of the nanofiltration system to reverse osmosis treatment.

[0087] In the present invention, the membrane separation unit includes at least one nanofiltration system, preferably two stages. When the membrane separation unit includes two nanofiltration systems, each nanofiltration system can produce corresponding filtrate and concentrated liquid, the first-stage filtrate is sent to the raw liquid pool of the second-stage nanofiltration system for secondary nanofiltration treatment; the second-stage concentrated liquid is refluxed to the raw liquid pool of the first-stage nanofiltration system for circulation, the first-stage concentrated liquid is a concentrated liquid containing metal calcium salt, part of which is discharged to the decalcification treatment unit, and the second-stage filtrate is a filtrate containing metal sodium salt.

[0088] According to the present invention, preferably, the membrane separation unit further comprises a microfiltration purification system for removing suspended matter and silt from the water phase flowing out of the electrical desalination unit and feeding the water phase into the nanofiltration system.

[0089] According to the present invention, preferably, the microfiltration membrane is selected from one or two of the average pore size (filtration accuracy) of 0.1-0.5 μm, 0.5-1 μm, 1-5 μm and 5-10 μm. In the present invention, the membrane separation unit includes at least one stage of microfiltration purification system, which can be a combination of microfiltration purification systems with different average pore sizes of microfiltration membranes.

[0090] According to the present invention, preferably, the evaporation-condensation unit comprises an evaporator and a condenser which are connected to each other.

[0091] According to the present invention, preferably, the decalcification treatment unit comprises:

[0092] A first solidification reaction tank is used to mix the concentrated solution of the reaction product of the calcium ions and the decalcifying agent flowing out of the nanofiltration system with a first precipitant to perform a first precipitation reaction;

[0093] A first solid-liquid separator, used for performing a first solid-liquid separation on the liquid flowing out of the first solidification reaction tank;

[0094] A second solidification reaction tank is used to mix the liquid product flowing out of the first solid-liquid separator with a second precipitant to perform a second precipitation reaction;

[0095] The second solid-liquid separator is used to perform a second solid-liquid separation on the material flowing out of the second solidification reaction tank, and the obtained liquid phase product, the condensed water flowing out of the condenser and the fresh water flowing out of the reverse osmosis system are mixed through a hydrocarbon oil decalcifying agent aqueous solution tank and then flow into the mixer.

[0096] According to the present invention, preferably, the decalcification treatment unit also includes: a first drying system for drying the solid phase product flowing out of the first solid-liquid separator to obtain a calcium salt product; and a second drying system for drying the solid phase product flowing out of the second solid-liquid separator to obtain a barium salt product.

[0097] According to a specific embodiment of the present invention, Figure 1 The method for removing metal ions from hydrocarbon oil in the device shown comprises the following steps:

[0098] S1, mixing a hydrocarbon oil decalcifying agent and water (based on the weight of the hydrocarbon oil, the contents of the hydrocarbon oil decalcifying agent and water are 0.01-5wt% and 1-25wt%, respectively) to obtain a decalcifying agent aqueous solution; fully mixing the decalcifying agent aqueous solution and the hydrocarbon oil 1 with a mixer 2 at a mixing pressure difference of 0.02-1MPa at 50-150° C., and controlling the diameter of the oil and water particles to be within the range of 0.1-50μm; then placing the oil-water mixture in an electric desalting tank 3, and leaving it for 1-60min at a temperature of 50-150° C. and an electric field strength of 50-500V / cm, and then leaving it for 5-200min at a temperature of 50-150° C. and an electric field strength of 500-1500V / cm; after separation of oil and water, obtaining a demetallized hydrocarbon oil 4 and a reacted decalcifying agent aqueous solution 5;

[0099] S2, the decalcifying agent aqueous solution 5 obtained after the reaction in S1 is pretreated by a microfiltration purification system 6 to remove suspended matter, silt and other impurities therein; the pretreated filtrate 7 is sent to a nanofiltration system 8 (using a monovalent ion selective permeable nanofiltration membrane) for treatment at a treatment pressure of 0.2-2MPa, 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 10 and a concentrated solution 9 of the reaction product of calcium ions and the decalcifying agent; the obtained sodium ion-containing filtrate 10 is sent to a reverse osmosis system 11 for reverse osmosis treatment, and the operating pressure of the reverse osmosis system is 2-6MPa to obtain fresh water 12 free of metal salts and a first sodium ion-containing concentrated solution 13;

[0100] S3, in the first solidification reaction tank 20, the concentrated solution 9 of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration system in S2 is subjected to a first precipitation reaction with sulfuric acid flowing out of the first 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 20-50°C, the time is 5-30min, and a feed liquid 21 containing calcium sulfate precipitate is generated; under the conditions of a temperature of 20-50°C and a pressure of -0.1MPa to 1MPa, a first solid-liquid separation is performed using a first solid-liquid separator 22 (centrifuge, the speed is 2500-3500r / min) to obtain a first recovered concentrated water 23 and a calcium sulfate solid residue, and the first recovered concentrated water 23 is discharged to the second solidification reaction tank 27; in the second solidification reaction tank 27, the first recovered concentrated water 2 3 and the barium chloride flowing out of the second precipitant storage tank 19 are subjected to a second precipitation reaction (the amount of barium chloride used is the theoretical amount of barium chloride when it completely reacts with the sulfate radical contained in the first recovered concentrated water), the reaction temperature is 20-50° C., the time is 5-30 min, and a feed liquid 28 containing barium sulfate precipitation is generated; under the conditions of a temperature of 20-50° C. and a pressure of -0.1 MPa to 1 MPa, a second solid-liquid separation is performed using a second solid-liquid separator 29 (centrifuge, the speed is 2500-3500 r / min) to obtain a second recovered concentrated water 33 (decalcified decalcifying agent concentrated liquid) and barium sulfate solid residue, and the second recovered concentrated water is discharged to a hydrocarbon oil decalcifying agent aqueous solution tank 34; wherein the obtained calcium sulfate solid residue and barium sulfate solid residue are respectively washed, separated and dried to obtain a calcium sulfate product and a barium sulfate product, respectively, which specifically includes the following steps:

[0101] Under the condition of 20-50° C., the calcium sulfate solid slag is washed with water in the calcium salt slag tank 24 (based on the weight of the calcium sulfate solid slag, the amount of water is 50-200wt%), allowed to stand for stratification, and the washing is repeated until the pH value of the washing water is 6-7 and the washing is stopped; the calcium slag is allowed to stand for sedimentation and stratification under the conditions of 20-50° C. and -0.1MPa to 1MPa, and the separated calcium slag is dried in the first drying system 25 at 100-200° C. to a moisture content of less than or equal to 1wt%, to obtain a calcium sulfate product 26;

[0102] At 20-50° C., the solid barium sulfate slag is washed with water in a barium salt slag tank 30 (the amount of water is 50-200wt% based on the weight of the solid barium sulfate slag), allowed to stand for stratification, and the water washing is repeated until the pH value of the washing water is 6-7; the water washing is stopped when the pH value of the washing water is 6-7; the separated barium slag is allowed to stand for sedimentation and stratification at 20-50° C. and -0.1MPa to 1MPa, and the separated barium slag is dried in a second drying system 31 at 100-200° C. to a moisture content of less than or equal to 1wt%, to obtain a barium sulfate product 32;

[0103] S4, in the evaporation and condensation unit 14, the first sodium ion-containing concentrated solution 13 obtained in S2 is evaporated and concentrated at 120-200° C., and condensed at 20-50° C. to obtain a second sodium ion-containing concentrated solution 15 and evaporated condensed water 16, and the obtained second sodium ion-containing concentrated solution 15 is placed in a brine storage tank 17; the evaporated condensed water, the second recovered concentrated water 33 (decalcified decalcifying agent concentrated solution) obtained in S3 and the fresh water 12 without metal salt obtained in S2 are mixed in a hydrocarbon oil decalcifying agent aqueous solution tank 34 to obtain a recovered aqueous solution 35 containing hydrocarbon oil decalcifying agent; when the concentration of hydrocarbon oil decalcifying agent in the recovered aqueous solution is higher than the required ratio of decalcifying agent to hydrocarbon oil, a certain amount of water 36 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, and then the aqueous solution is returned to S1 for recycling.

[0104] The present invention will be described in detail below through examples and comparative examples. In the following examples and comparative examples, unless otherwise specified, all are conventional methods; the reagents and materials used, unless otherwise specified, can be obtained from commercial channels. The test methods involved in the following examples and comparative examples are as follows:

[0105] Analysis method for metal ions in hydrocarbon oil: RIPP124-1990 plasma emission spectrometry;

[0106] Analysis method of metal ions in water: RIPP124-1990 plasma emission spectrometry;

[0107] Analysis method of sulfate ion in water: GB 11899 Water quality, determination of sulfate, gravimetric method;

[0108] Analysis method of phosphate ion in water: GB / T14642-2009 Determination of fluoride, chlorine, phosphate, nitrite, nitrate and sulfate in industrial circulating cooling water and boiler water, ion chromatography;

[0109] Decalcifying agent concentration analysis method: liquid chromatography.

[0110] The following examples are used to illustrate the Figure 1 The flowchart shown is a method for resource utilization of hydrocarbon oil demetallization and decalcification wastewater.

[0111] Example 1

[0112] The hydrocarbon oil to be treated in this embodiment is a minus four fraction oil, and the metal ion contents are: calcium ion 40.4 μg / g, magnesium ion 5.13 μg / g, sodium ion 2.8 μg / g.

[0113] The following steps are used to remove metal ions from hydrocarbon oil:

[0114] S1. Mixing hydrocarbon oil decalcifying agent (formic acid) and water (based on the weight of the oil minus four fractions, the contents of hydrocarbon oil decalcifying agent and water are 0.01wt% and 25wt%, respectively) to obtain a decalcifying agent aqueous solution; fully mixing the decalcifying agent aqueous solution and the oil minus four fractions with a static mixer at a mixing pressure difference of 0.02MPa for 1 min at 50°C; then placing the oil-water mixture in an electric desalting tank, staying for 1 min at a temperature of 50°C and an electric field strength of 50V / cm, and then staying for 5 min 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 demetallized hydrocarbon oil has a calcium content of 1.5μg / g, a magnesium content of 0.21μg / g, and a sodium content of 0.8μg / g; the calcium content of the decalcifying agent aqueous solution after reaction is 0.02wt%, and the sodium content is 0.001wt%;

[0115] S2. The decalcifying agent aqueous solution obtained in S1 is pretreated by a microfiltration purification system (composed of two-stage microfiltration systems with filtration accuracies 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. The pretreated filtrate is sequentially sent to a primary nanofiltration system and a secondary nanofiltration system (both the two-stage nanofiltration systems 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 at a treatment pressure of 0.3 MPa. 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%, and the retention rate of sodium ions is 10%; the recovery rate of the filtrate is 85%. The obtained sodium ion-containing filtrate is sent to a reverse osmosis system (using a spiral reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 2 MPa, and fresh water without metal salts and a first sodium ion-containing concentrate are obtained. The sodium salt rejection rate is 97%, and the fresh water recovery rate is 85%;

[0116] S3, in the first solidification reaction tank, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration system in S2 is subjected to a first precipitation reaction with sulfuric acid flowing out of the first precipitant storage tank (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; a first solid-liquid separation is performed by a centrifuge at a speed of 3000r / min to obtain a first recovered concentrated water and a calcium sulfate solid residue, and the first recovered concentrated water is discharged to the second solidification reaction tank; in the second solidification reaction tank, the first recovered concentrated water (sulfate content The first recovery concentrated water is 1500mg / L) and the barium chloride flowing out of the second precipitant storage tank is subjected to a second precipitation reaction (the amount of barium chloride used is the theoretical amount of barium chloride when it completely reacts with the sulfate radical contained in the first recovery concentrated water), the reaction temperature is 20°C, the time is 5min, and a feed liquid containing barium sulfate precipitation is generated; a second solid-liquid separation is performed by a centrifuge at a speed of 3000r / min to obtain a second recovery concentrated water and a barium sulfate solid residue, and the second recovery concentrated water is discharged into a hydrocarbon oil decalcification agent aqueous solution tank; wherein the obtained calcium sulfate solid residue and barium sulfate solid residue are respectively washed, separated and dried to obtain a calcium sulfate product and a barium sulfate product, respectively, which specifically comprises the following steps:

[0117] Under normal temperature, the calcium sulfate solid slag is washed with water in a calcium salt slag tank (based on the weight of the calcium sulfate solid slag, the 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 then the washing is stopped; the calcium slag is allowed to stand for sedimentation and stratification at normal temperature and pressure, and the separated calcium slag is dried in a first drying system at 120° C. until the moisture content is less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of the calcium sulfate is 92.7wt%, reaching the quality standard of building gypsum);

[0118] Under normal temperature conditions, the solid barium sulfate slag is washed with water in a barium salt slag tank (based on the weight of the solid barium sulfate slag, the 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; the separated barium slag is allowed to stand for sedimentation and stratification at normal temperature and pressure, and the separated barium slag is dried in a second drying system at 120° C. until the moisture content is less than or equal to 1wt%, to obtain a barium sulfate product (the purity of barium sulfate is 93.1wt%, reaching the quality standard of precipitated barium sulfate);

[0119] S4. In the evaporation and condensation unit, the first sodium ion-containing concentrated solution obtained in S2 is evaporated and concentrated at 120° C., and condensed at 20° C. to obtain a second sodium ion-containing concentrated solution and evaporation condensate water. The obtained second sodium ion-containing concentrated solution (the sodium salt content is 10wt%, meeting the quality standard of brine drilling fluid) is placed in a brine storage tank; the evaporation condensate water, the second recovered concentrated water obtained in S3 and the fresh water without metal salt obtained in S2 are mixed in a hydrocarbon oil decalcifying agent aqueous solution tank, and the obtained recovered aqueous solution containing hydrocarbon oil decalcifying agent (sulfate content is 83mg / L) is returned to S1 for recycling.

[0120] Example 2

[0121] The hydrocarbon oil to be treated in this embodiment is crude oil, and the metal ion contents are: calcium ion 520 μg / g, magnesium ion 5.64 μg / g, and sodium ion 120.1 μg / g.

[0122] The following steps are used to remove metal ions from hydrocarbon oil:

[0123] S1. Mixing hydrocarbon oil decalcifying agent (acetic acid) and water (based on the weight of crude oil, the contents of hydrocarbon oil decalcifying agent and water are 0.52wt% and 8wt%, respectively) to obtain a decalcifying agent aqueous solution; fully mixing the decalcifying agent aqueous solution and crude oil with a stirrer for 30 minutes at a temperature of 150° C. and a pressure of 1MPa; then placing the oil-water mixture in an electric desalting tank, staying for 60 minutes at a temperature of 150° C. and an electric field strength of 500V / cm, and then staying for 200 minutes at a temperature of 150° C. and an electric field strength of 1000V / cm; after oil-water separation, demetallized hydrocarbon oil and a decalcifying agent aqueous solution after reaction are obtained; analysis shows that the demetallized hydrocarbon oil has a calcium content of 13.2μg / g, a magnesium content of 0.2μg / g, and a sodium content of 1μg / g; the calcium content of the decalcifying agent aqueous solution after reaction is 0.25wt%, and the sodium content is 0.059wt%;

[0124] S2. The decalcifying agent aqueous solution obtained after the reaction in S1 is pretreated by a microfiltration purification system (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. The pretreated filtrate is sequentially sent to a primary nanofiltration system and a secondary nanofiltration system (both the two-stage nanofiltration systems 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 at a treatment pressure of 2 MPa. 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 96%, and the retention rates of sodium ions are both 10%; the recovery rate of the filtrate is 85%. The obtained sodium ion-containing filtrate is sent to a reverse osmosis system (using a spiral reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 2 MPa, and fresh water without metal salts and a first sodium ion-containing concentrate are obtained. The sodium salt rejection rate is 98%, and the fresh water recovery rate is 75%;

[0125] S3, in the first solidification reaction tank, the concentrated solution of the reaction product of calcium ions and the decalcifying agent discharged from the nanofiltration system in S2 is subjected to a first precipitation reaction with the phosphoric acid discharged from the first precipitant storage tank (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 45°C, the time is 30min, and a feed liquid containing calcium phosphate precipitate is generated; under the conditions of a temperature of 45°C and a pressure of 0.15MPa, a first solid-liquid separation is performed through a filter to obtain a first recovered concentrated water and a calcium phosphate solid residue, and the first recovered concentrated water is discharged to the second solidification reaction tank; in the second solidification reaction tank, the first recovered concentrated water ( The invention discloses a method for preparing a first recovery concentrated water having a phosphate content of 780 mg / L) and barium chloride flowing out of a second precipitant storage tank for a second precipitation reaction (the amount of barium chloride used is the theoretical amount of barium chloride used when the phosphate contained in the first recovery concentrated water is completely reacted), the reaction temperature is 45° C., the time is 30 min, and a slurry containing barium phosphate precipitate is generated; a second solid-liquid separation is performed by a centrifuge at a speed of 3000 r / min to obtain a second recovery concentrated water and a barium phosphate solid residue, and the second recovery concentrated water is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank; wherein the obtained calcium phosphate solid residue and barium phosphate solid residue are respectively washed, separated and dried to obtain a calcium phosphate product and a barium phosphate product, respectively, which specifically comprises the following steps:

[0126] Under normal temperature conditions, the calcium phosphate solid slag is washed with water (based on the weight of the calcium phosphate solid slag, the amount of water is 160wt%) in a calcium salt slag tank, allowed to stand for stratification, and the water washing is repeated until the pH value of the washing water reaches 7 and the water washing is stopped; the calcium phosphate solid slag is allowed to stand for sedimentation and stratification at normal temperature and pressure, and the separated calcium slag is dried in a first drying system at 120° C. until the moisture content is less than or equal to 1wt%, to obtain a calcium phosphate product (the purity of the calcium phosphate is 93.1wt%, meeting the quality standard of building materials);

[0127] Under normal temperature conditions, the solid barium phosphate slag is washed with water in a barium salt slag tank (the amount of water is 160wt% based on the weight of the solid barium phosphate slag), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water reaches 7; the separated barium slag is allowed to stand for sedimentation and stratification at normal temperature and pressure, and the separated barium slag is dried in a second drying system at 120° C. until the moisture content is less than or equal to 1wt%, to obtain a barium phosphate product (barium phosphate purity is 95.7wt%);

[0128] S4. In the evaporation and condensation unit, the first sodium ion-containing concentrated solution obtained in S2 is evaporated and concentrated at 200° C., and condensed at 50° C. to obtain a second sodium ion-containing concentrated solution and evaporation condensate water. The obtained second sodium ion-containing concentrated solution (the sodium salt content is 30wt%, meeting the quality standard of brine drilling fluid) is placed in a brine storage tank; the evaporation condensate water, the second recovered concentrated water obtained in S3 and the fresh water without metal salt obtained in S2 are mixed in a hydrocarbon oil decalcifying agent aqueous solution tank, and the obtained recovered aqueous solution containing hydrocarbon oil decalcifying agent (phosphate content is 55mg / L) is returned to S1 for recycling.

[0129] Example 3

[0130] The hydrocarbon oil to be treated in this embodiment is thick oil, and the metal ion contents are: calcium ion 712 μg / g, magnesium ion 2.53 μg / g, and sodium ion 95.8 μg / g.

[0131] The following steps are used to remove metal ions from hydrocarbon oil:

[0132] S1. Mixing a hydrocarbon oil decalcifying agent (propionic acid) and water (based on the weight of the heavy oil, the contents of the hydrocarbon oil decalcifying agent and water are 0.25wt% and 20wt%, respectively) to obtain a decalcifying agent aqueous solution; shearing the decalcifying agent aqueous solution and the heavy oil with an emulsifying shearing instrument for 15 minutes at a temperature of 120° C. and a pressure of 0.5 MPa; then placing the oil-water mixture in an electric desalting tank, staying for 30 minutes at a temperature of 120° C. and an electric field strength of 400V / cm, and then staying 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 in 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 in the decalcifying agent aqueous solution after reaction is 0.34wt%, and the sodium content is 0.047wt%;

[0133] S2. The decalcifying agent aqueous solution obtained in S1 is pretreated by a microfiltration purification system (composed of two-stage microfiltration systems with filtration accuracies 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. The pretreated filtrate is sequentially sent to a primary nanofiltration system and a secondary nanofiltration system (both the two-stage nanofiltration systems 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 at a treatment pressure of 0.2 MPa. 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 99%, and the retention rates of sodium ions are both 1%; the recovery rate of the filtrate is 84%. The obtained sodium ion-containing filtrate is sent to a reverse osmosis system (using a spiral reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 4 MPa, and fresh water without metal salts and a first sodium ion-containing concentrate are obtained. The sodium salt rejection rate is 97%, and the fresh water recovery rate is 80%;

[0134] S3, in the first solidification reaction tank, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration system in S2 is subjected to a first precipitation reaction with sulfuric acid flowing out of the first precipitant storage tank (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; a first solid-liquid separation is performed with a suction filter at a temperature of 30°C and a pressure of -0.08MPa to obtain a first recovered concentrated water and a calcium sulfate solid residue, and the first recovered concentrated water is discharged to the second solidification reaction tank; in the second solidification reaction tank, the first recovered concentrated water ( The second precipitation reaction is carried out by using a centrifuge at a speed of 3000r / min to separate the second solid from the concentrated water and the barium sulfate solid residue, and the second concentrated water is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank; wherein the obtained calcium sulfate solid residue and barium sulfate solid residue are washed, separated and dried respectively to obtain a calcium sulfate product and a barium sulfate product respectively, which specifically comprises the following steps:

[0135] Under normal temperature conditions, the calcium sulfate solid slag is washed with water in a calcium salt slag tank (based on the weight of the calcium sulfate solid slag, the amount of water is 200wt%), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water is 6.2 and the washing is stopped; the calcium slag is allowed to stand for sedimentation and stratification at normal temperature and pressure, and the separated calcium slag is dried in a first drying system at 120° C. until the moisture content is less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of the calcium sulfate is 92.7wt%, meeting the quality standard of building gypsum);

[0136] Under normal temperature conditions, the solid barium sulfate slag is washed with water in a barium salt slag tank (the weight of the solid barium sulfate slag is used as the basis, and the amount of water is 200wt%), allowed to stand for stratification, and the water washing is repeated until the pH value of the washing water is 6.2 and the water washing is stopped; the separated barium slag is allowed to stand for sedimentation and stratification at normal temperature and pressure, and the separated barium slag is dried in a second drying system at 120° C. until the moisture content is less than or equal to 1wt%, to obtain a barium sulfate product (the purity of the barium sulfate is 94.1wt%, reaching the quality standard of precipitated barium sulfate);

[0137] S4, in the evaporation and condensation unit, the first sodium ion-containing concentrated solution obtained in S2 is evaporated and concentrated at 160° C., and condensed at 40° C. to obtain a second sodium ion-containing concentrated solution and evaporation condensate water, and the obtained second sodium ion-containing concentrated solution (the sodium salt content is 20wt%, meeting the quality standard of brine drilling fluid) is placed in a brine storage tank; the evaporation condensate water, the second recovered concentrated water obtained in S3 and the fresh water without metal salt obtained in S2 are mixed in a hydrocarbon oil decalcifying agent aqueous solution tank, and the obtained recovered aqueous solution containing hydrocarbon oil decalcifying agent (sulfate content is 46mg / L) is returned to S1 for recycling.

[0138] Example 4

[0139] The hydrocarbon oil to be treated in this embodiment is super-heavy oil, and the metal ion contents are: calcium ion 1380 μg / g, magnesium ion 14.32 μg / g, and sodium ion 282 μg / g.

[0140] The following steps are used to remove metal ions from hydrocarbon oil:

[0141] S1. Mixing a hydrocarbon oil decalcifying agent (butyric acid) and water (based on the weight of the super heavy oil, the contents of the hydrocarbon oil decalcifying agent and water are 1.38wt% and 15wt%, respectively) to obtain a decalcifying agent aqueous solution; fully mixing the decalcifying agent aqueous solution and the super heavy oil in a membrane reactor using a metal membrane with a membrane pore size of 10μm as a membrane material at a temperature of 150°C and a pressure of 0.3MPa; then placing the oil-water mixture in an electric desalting tank at a temperature of 150°C and an electric field strength of The reaction mixture was kept at a temperature of 150°C and an electric field strength of 300 V / cm for 20 minutes, and then kept at a temperature of 150°C and an electric field strength of 1400 V / cm for 90 minutes. After oil-water separation, a demetallized hydrocarbon oil and a decalcifying agent aqueous solution after the reaction were obtained. Analysis showed that the calcium content of the hydrocarbon oil after metal ion removal was 37.8 μg / g, the magnesium content was 0.78 μg / g, and the sodium content was 1.5 μg / g. The calcium content of the decalcifying agent aqueous solution after the reaction was 0.67 wt%, and the sodium content was 0.14 wt%.

[0142] S2. The decalcifying agent aqueous solution obtained in S1 is pretreated by a microfiltration purification system (composed of two-stage microfiltration systems 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. The pretreated filtrate is sequentially sent to a primary nanofiltration system and a secondary nanofiltration system (both the two-stage nanofiltration systems 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 at a treatment pressure of 0.3 MPa. 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 96%, and the retention rate of sodium ions is 7%; the recovery rate of the filtrate is 75%. The obtained sodium ion-containing filtrate is sent to a reverse osmosis system (using a spiral reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 6 MPa, and fresh water without metal salts and a first sodium ion-containing concentrate are obtained. The sodium salt rejection rate is 98%, and the fresh water recovery rate is 78%;

[0143] S3, in the first solidification reaction tank, the concentrated solution of the reaction product of calcium ions and the decalcifying agent discharged from the nanofiltration system in S2 is subjected to a first precipitation reaction with sulfuric acid discharged from the first precipitant storage tank (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 condition of a pressure of 0.02MPa, a first solid-liquid separation is performed using a hydrocyclone separator to obtain a first recovered concentrated water and a calcium sulfate solid residue, and the first recovered concentrated water is discharged to the second solidification reaction tank; in the second solidification reaction tank, the first recovered concentrated water (sulfate content The first step is to carry out a second precipitation reaction with barium acetate (the amount of barium acetate is the theoretical amount of barium acetate when the barium acetate is completely reacted with the sulfate radical contained in the first recovered concentrated water) at a reaction temperature of 20° C. for 20 min to generate a feed solution containing barium sulfate precipitation; the second solid-liquid separation is carried out through a cyclone separator under a pressure of 0.02 MPa to obtain a second recovered concentrated water and a barium sulfate solid residue, and the second recovered concentrated water is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank; wherein the obtained calcium sulfate solid residue and barium sulfate solid residue are respectively washed, separated and dried to obtain a calcium sulfate product and a barium sulfate product, respectively, which specifically comprises the following steps:

[0144] Under normal temperature, the calcium sulfate solid slag is washed with water in a calcium salt slag tank (based on the weight of the calcium sulfate solid slag, the amount of water is 150wt%), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water reaches 7, and the washing is stopped; suction filtration is performed under the conditions of a temperature of 30° C. and a pressure of −0.5MPa, and the separated calcium slag is dried at 150° C. in a first drying system until the moisture content is less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of the calcium sulfate is 94.3wt%, reaching the quality standard of building gypsum);

[0145] Under normal temperature conditions, the solid barium sulfate slag is washed with water in a barium salt slag tank (based on the weight of the solid barium sulfate slag, the amount of water is 150wt%), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water reaches 7; the washing is stopped; under a pressure of 0.02Mpa, the separated barium slag is dried in a second drying system at 110°C to a moisture content of less than or equal to 1wt%, to obtain a barium sulfate product (the purity of barium sulfate is 93.7wt%, meeting the quality standard of precipitated barium sulfate);

[0146] S4, in the evaporation and condensation unit, the first sodium ion-containing concentrated solution obtained in S2 is evaporated and concentrated at 120° C., and condensed at 30° C. to obtain a second sodium ion-containing concentrated solution and evaporation condensate water, and the obtained second sodium ion-containing concentrated solution (the sodium salt content is 30wt%, meeting the quality standard of brine drilling fluid) is placed in a brine storage tank; the evaporation condensate water, the second recovered concentrated water obtained in S3 and the fresh water without metal salt obtained in S2 are mixed in a hydrocarbon oil decalcifying agent aqueous solution tank, and the obtained recovered aqueous solution containing hydrocarbon oil decalcifying agent (sulfate content is 45mg / L) is returned to S1 for recycling.

[0147] Example 5

[0148] The hydrocarbon oil to be treated in this embodiment is waste oil, and the metal ion contents are: calcium ion 27.3 μg / g, magnesium ion 0.32 μg / g, sodium ion 0.8 μg / g.

[0149] The following steps are used to remove metal ions from hydrocarbon oil:

[0150] S1, hydrocarbon oil decalcification agent (acetic acid) and water are mixed (based on the weight of the dirty oil, the contents of hydrocarbon oil decalcification agent and water are 0.01wt% and 1wt%, respectively) to obtain a decalcification agent aqueous solution; the decalcification agent aqueous solution and the dirty oil are fully mixed with a stirrer for 15min at a temperature of 50°C and a pressure of 0.02MPa; the oil-water mixture is then placed in an electric desalting tank, and stays for 20min at a temperature of 50°C and an electric field strength of 50V / cm, and then stays for 50min at a temperature of 50°C and an electric field strength of 500V / cm; after oil-water separation, demetallized hydrocarbon oil and a decalcification agent aqueous solution after reaction are obtained; analysis shows that the demetallized hydrocarbon oil has a calcium content of 0.5μg / g, a magnesium content of 0.2μg / g, and a sodium content of 0.5μg / g; the calcium content of the decalcification agent aqueous solution after reaction is 0.014wt%, and the sodium content is 0.0002wt%;

[0151] S2. The decalcifying agent aqueous solution obtained in S1 is pretreated by a microfiltration purification system (composed of two-stage microfiltration systems with filtration accuracies of 8 μm and 0.4 μm, respectively, and the materials of the microfiltration membranes are polycarbonate and polytetrafluoroethylene, respectively) to remove suspended matter, sediment and other impurities therein. The pretreated filtrate is sequentially sent to a primary nanofiltration system and a secondary nanofiltration system (both the two-stage nanofiltration systems 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 at a treatment pressure of 1.8 MPa. 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 96%, and the retention rate of sodium ions is 2%; the recovery rate of the filtrate is 83%. The obtained sodium ion-containing filtrate is sent to a reverse osmosis system (using a spiral reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 6 MPa, and fresh water without metal salts and a first sodium ion-containing concentrate are obtained. The sodium salt rejection rate is 97%, and the fresh water recovery rate is 85%;

[0152] S3, in the first solidification reaction tank, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration system in S2 is subjected to a first precipitation reaction with sulfuric acid flowing out of the first precipitant storage tank (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), and the reaction is carried out at room temperature for 5 minutes to generate a feed liquid containing calcium sulfate precipitate; a centrifuge is used to perform a first solid-liquid separation at a speed of 3000r / min to obtain a first recovered concentrated water and a calcium sulfate solid residue, and the first recovered concentrated water is discharged to the second solidification reaction tank; in the second solidification reaction tank, the first recovered concentrated water (sulfate content is 1710mg / L) is subjected to a second precipitation reaction with barium acetate flowing out of a second precipitant storage tank (the amount of barium acetate used is the theoretical amount of barium acetate when it completely reacts with sulfate radicals contained in the first recovered concentrated water), and the reaction is carried out at room temperature for 30min to generate a feed liquid containing barium sulfate precipitation; a second solid-liquid separation is carried out by a centrifuge at a speed of 3000r / min to obtain a second recovered concentrated water and barium sulfate solid residue, and the second recovered concentrated water is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank; wherein the obtained calcium sulfate solid residue and barium sulfate solid residue are respectively washed, separated and dried to obtain a calcium sulfate product and a barium sulfate product, respectively, which specifically comprises the following steps:

[0153] At 25° C., washing the calcium sulfate solid slag in a calcium salt slag tank (with the weight of the calcium sulfate solid slag as the benchmark, the amount of water is 50wt%), standing for stratification, and repeatedly washing with water until the pH value of the washing water is 6.9 and the washing is stopped; filtering under the conditions of a temperature of 25° C. and a pressure of -0.75MPa, and drying the separated calcium slag at 175° C. in a first drying system until the moisture content is less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of the calcium sulfate is 98.2wt%, reaching the quality standard of building gypsum);

[0154] Under normal temperature conditions, the solid barium sulfate slag is washed with water in a barium salt slag tank (the weight of the solid barium sulfate slag is used as the basis, and the amount of water is 50wt%), allowed to stand for stratification, and the water washing is repeated until the pH value of the washing water reaches 7 and the water washing is stopped; the separated barium slag is allowed to stand for sedimentation and stratification at normal temperature and pressure, and the separated barium slag is dried in a second drying system at 120° C. until the moisture content is less than or equal to 1wt%, to obtain a barium sulfate product (the purity of the barium sulfate is 95wt%, meeting the quality standard of precipitated barium sulfate);

[0155] S4, in the evaporation and condensation unit, the first sodium ion-containing concentrated solution obtained in S2 is evaporated and concentrated at 160° C., and condensed at 50° C. to obtain a second sodium ion-containing concentrated solution and evaporation condensate water, and the obtained second sodium ion-containing concentrated solution (the sodium salt content is 10wt%, meeting the quality standard of brine drilling fluid) is placed in a brine storage tank; the evaporation condensate water, the second recovered concentrated water obtained in S3 and the fresh water without metal salt obtained in S2 are mixed in a hydrocarbon oil decalcifying agent aqueous solution tank, and the obtained recovered aqueous solution containing hydrocarbon oil decalcifying agent (sulfate content is 48mg / L) is returned to S1 for recycling.

[0156] Example 6

[0157] The hydrocarbon oil to be treated in this embodiment is crude oil, and the metal ion contents are: calcium ion 208 μg / g, magnesium ion 3.14 μg / g, and sodium ion 41.7 μg / g.

[0158] The following steps are used to remove metal ions from hydrocarbon oil:

[0159] S1. Mixing hydrocarbon oil decalcifying agent (acetic acid) and water (based on the weight of crude oil, the contents of hydrocarbon oil decalcifying agent and water are 0.07wt% and 7wt%, respectively) to obtain a decalcifying agent aqueous solution; fully mixing the decalcifying agent aqueous solution and crude oil with a static mixer at a temperature of 130° C. and a pressure of 0.08MPa for 10 min; then placing the oil-water mixture in an electric desalting tank, staying for 40 min at a temperature of 130° C. and an electric field strength of 300V / cm, and then staying for 100 min at a temperature of 130° C. and an electric field strength of 900V / cm; after oil-water separation, demetallized hydrocarbon oil and a decalcifying agent aqueous solution after reaction are obtained; analysis shows that the demetallized hydrocarbon oil has a calcium content of 23.9μg / g, a magnesium content of 0.41μg / g, and a sodium content of 1.8μg / g; the calcium content of the decalcifying agent aqueous solution after reaction is 0.09wt%, and the sodium content is 0.02wt%;

[0160] S2. The decalcifying agent aqueous solution obtained after the reaction in S1 is pretreated by a microfiltration purification system (composed of a two-stage microfiltration system with filtration accuracy 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. The pretreated filtrate is sequentially sent to a primary nanofiltration system and a secondary nanofiltration system (both the two-stage nanofiltration systems 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 at a treatment pressure of 0.8 MPa. 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%, and the retention rate of sodium ions is 4%; the recovery rate of the filtrate is 85%. The obtained sodium ion-containing filtrate is sent to a reverse osmosis system (using a spiral reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 4 MPa, and fresh water without metal salts and a first sodium ion-containing concentrate are obtained. The sodium salt rejection rate is 97%, and the fresh water recovery rate is 85%;

[0161] S3, in the first solidification reaction tank, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration system in S2 is subjected to a first precipitation reaction with sulfuric acid flowing out of the first precipitant storage tank (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; a filter is used to perform a first solid-liquid separation under the conditions of a temperature of 35°C and a pressure of 0.25MPa to obtain a first recovered concentrated water and a calcium sulfate solid residue, and the first recovered concentrated water is discharged to the second solidification reaction tank; in the second solidification reaction tank, the first recovered concentrated water (sulfur) is discharged to the second solidification reaction tank; The acid radical content is 1820mg / L) and the barium hydroxide flowing out of the second precipitant storage tank are subjected to a second precipitation reaction (the amount of barium hydroxide used is the theoretical amount of barium hydroxide when it completely reacts with the sulfate radical contained in the first recovered concentrated water), the reaction temperature is 35°C, the time is 5min, and a feed liquid containing barium sulfate precipitation is generated; a second solid-liquid separation is performed by a centrifuge at a speed of 3000r / min to obtain a second recovered concentrated water and barium sulfate solid residue, and the second recovered concentrated water is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank; wherein the obtained calcium sulfate solid residue and barium sulfate solid residue are respectively washed, separated and dried to obtain a calcium sulfate product and a barium sulfate product, respectively, which specifically comprises the following steps:

[0162] Under the condition of 35° C., washing the calcium sulfate solid slag with water (based on the weight of the calcium sulfate solid slag, the amount of water is 100wt%) in a calcium salt slag tank, standing for stratification, and repeatedly washing with water until the pH value of the washing water reaches 7, and then stopping the washing; centrifuging at 35° C. and normal pressure with a centrifuge at a speed of 3500r / min, and drying the separated calcium slag at 160° C. in a first drying system until the moisture content is less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of the calcium sulfate is 95.2wt%, reaching the quality standard of building gypsum);

[0163] Under normal temperature conditions, the solid barium sulfate slag is washed with water in a barium salt slag tank (the weight of the solid barium sulfate slag is used as the basis, and the amount of water is 200wt%), allowed to stand for stratification, and the water washing is repeated until the pH value of the washing water is 7 and the water washing is stopped; the separated barium slag is allowed to stand for sedimentation and stratification at normal temperature and pressure, and the separated barium slag is dried in a second drying system at 120° C. until the moisture content is less than or equal to 1wt%, to obtain a barium sulfate product (the purity of the barium sulfate is 97.1wt%, reaching the quality standard of precipitated barium sulfate);

[0164] S4, in the evaporation and condensation unit, the first sodium ion-containing concentrated solution obtained in S2 is evaporated and concentrated at 200° C., and condensed at 40° C. to obtain a second sodium ion-containing concentrated solution and evaporation condensate water, and the obtained second sodium ion-containing concentrated solution (the sodium salt content is 18wt%, meeting the quality standard of brine drilling fluid) is placed in a brine storage tank; the evaporation condensate water, the second recovered concentrated water obtained in S3 and the fresh water without metal salt obtained in S2 are mixed in a hydrocarbon oil decalcifying agent aqueous solution tank, and the obtained recovered aqueous solution containing hydrocarbon oil decalcifying agent (sulfate content is 52mg / L) is returned to S1 for recycling.

[0165] Example 7

[0166] The hydrocarbon oil to be treated in this embodiment 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.

[0167] The following steps are used to remove metal ions from hydrocarbon oil:

[0168] S1. Mixing a hydrocarbon oil decalcifying agent (formic acid) and water (based on the weight of the residual oil, the contents of the hydrocarbon oil decalcifying agent and water are 1.47wt% and 11wt%, respectively) to obtain a decalcifying agent aqueous solution; mixing the decalcifying agent aqueous solution and the residual oil with an emulsifying shearing instrument at a temperature of 135° C. and a pressure of 0.6MPa; then placing the oil-water mixture in an electric desalting tank, staying for 30 minutes at a temperature of 135° C. and an electric field strength of 200V / cm, and then staying for 150 minutes at a temperature of 135° C. and an electric field strength of 1100V / cm; after oil-water separation, obtaining demetallized hydrocarbon oil and a decalcifying agent aqueous solution after reaction; analyzing the demetallized hydrocarbon oil to obtain a calcium content of 72μg / g, a magnesium content of 1.64μg / g, and a sodium content of 1.7μg / g; the calcium content of the decalcifying agent aqueous solution after reaction is 0.7wt%, and the sodium content is 0.061wt%;

[0169] S2. The decalcifying agent aqueous solution obtained after the reaction in S1 is pretreated by a microfiltration purification system (composed of a two-stage microfiltration system with filtration accuracy 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. The pretreated filtrate is sequentially sent to a primary nanofiltration system and a secondary nanofiltration system (both the two-stage nanofiltration systems 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 at a treatment pressure of 2 MPa. 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 96%, and the retention rate of sodium ions is 10%; the recovery rate of the filtrate is 75%. The obtained sodium ion-containing filtrate is sent to a reverse osmosis system (using a spiral reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 5 MPa, and fresh water without metal salts and a first sodium ion-containing concentrate are obtained. The sodium salt rejection rate is 98%, and the fresh water recovery rate is 75%;

[0170] S3, in the first solidification reaction tank, the concentrated solution of the reaction product of calcium ions and the decalcifying agent flowing out of the nanofiltration system in S2 is subjected to a first precipitation reaction with sulfuric acid flowing out of the first precipitant storage tank (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; a first solid-liquid separation is performed using a hydrocyclone separator at a temperature of 40°C and a pressure of 0.35MPa to obtain a first recovered concentrated water and a calcium sulfate solid residue, and the first recovered concentrated water is discharged to the second solidification reaction tank; in the second solidification reaction tank, the first recovered concentrated water is discharged to the second solidification reaction tank; Water (sulfate content of 1580 mg / L) and barium chloride flowing out of the second precipitant storage tank are subjected to a second precipitation reaction (the amount of barium chloride used is the theoretical amount of barium chloride when it completely reacts with the sulfate contained in the first recovered concentrated water), the reaction temperature is 40°C, the time is 5 minutes, and a feed liquid containing barium sulfate precipitation is generated; a centrifuge is used to perform a second solid-liquid separation at a speed of 3000 r / min to obtain a second recovered concentrated water and barium sulfate solid residue, and the second recovered concentrated water is discharged into a hydrocarbon oil decalcification agent aqueous solution tank; wherein the obtained calcium sulfate solid residue and barium sulfate solid residue are respectively washed, separated and dried to obtain a calcium sulfate product and a barium sulfate product, respectively, which specifically includes the following steps:

[0171] At 40° C., washing the calcium sulfate solid slag in a calcium salt slag tank (with the weight of the calcium sulfate solid slag as the benchmark, the amount of water is 100wt%), standing for stratification, and repeatedly washing until the pH value of the washing water is 7, and then stopping the washing; filtering with a hydrocyclone separator at a temperature of 40° C. and a pressure of 0.35MPa, and drying the separated calcium slag at 160° C. in a first drying system to a moisture content of less than or equal to 1wt%, to obtain a calcium sulfate product (the purity of the calcium sulfate is 96.2wt%, reaching the quality standard of building gypsum);

[0172] At 40° C., washing the solid barium sulfate slag with water in a barium salt slag tank (based on the weight of the solid barium sulfate slag, the amount of water is 150wt%), standing for stratification, and repeatedly washing with water until the pH value of the washing water reaches 6.5; standing for sedimentation and stratification at a temperature of 40° C. and normal pressure, and drying the separated barium slag at 135° C. in a second drying system until the moisture content is less than or equal to 1wt%, to obtain a barium sulfate product (the purity of barium sulfate is 95.7wt%, meeting the quality standard of precipitated barium sulfate);

[0173] S4, in the evaporation and condensation unit, the first sodium ion-containing concentrated solution obtained in S2 is evaporated and concentrated at 150° C., and condensed at 20° C. to obtain a second sodium ion-containing concentrated solution and evaporation condensate water, and the obtained second sodium ion-containing concentrated solution (the sodium salt content is 17wt%, meeting the quality standard of brine drilling fluid) is placed in a brine storage tank; the evaporation condensate water, the second recovered concentrated water obtained in S3 and the fresh water without metal salt obtained in S2 are mixed in a hydrocarbon oil decalcifying agent aqueous solution tank, and the obtained recovered aqueous solution containing hydrocarbon oil decalcifying agent (sulfate content is 45mg / L) is returned to S1 for recycling.

[0174] Example 8

[0175] The hydrocarbon oil to be treated in this embodiment is super-heavy oil, and the metal ion contents are: calcium ion 1980 μg / g, magnesium ion 23.7 μg / g, and sodium ion 98.1 μg / g.

[0176] The following steps are used to remove metal ions from hydrocarbon oil:

[0177] S1, hydrocarbon oil decalcification agent (formic acid) and water are mixed (based on the weight of super heavy oil, the contents of hydrocarbon oil decalcification agent and water are 1.8wt% and 20wt%, respectively) to obtain a decalcification agent aqueous solution; at a temperature of 120° C. and a pressure of 1MPa, the decalcification agent aqueous solution is mixed with a membrane reactor made of a metal membrane with a pore size of 50μm for super heavy oil; then the oil-water mixture is placed in an electric desalting tank, and stays for 6min at a temperature of 120° C. and an electric field strength of 250V / cm, and then stays for 60min at a temperature of 120° C. and an electric field strength of 750V / cm; after oil-water separation, demetallized hydrocarbon oil and a decalcification agent aqueous solution after reaction are obtained; analysis shows that the calcium content in the demetallized 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 decalcification agent aqueous solution after reaction is 0.97wt%, and the sodium content is 0.048wt%;

[0178] S2. The decalcifying agent aqueous solution obtained after the reaction in S1 is pretreated by a microfiltration purification system (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. The pretreated filtrate is sequentially sent to a primary nanofiltration system and a secondary nanofiltration system (both the two-stage nanofiltration systems 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 at a treatment pressure of 2 MPa. 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 98%, and the retention rate of sodium ions is 5%; the recovery rate of the filtrate is 75%. The obtained sodium ion-containing filtrate is sent to a reverse osmosis system (using a spiral reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 6 MPa, and fresh water without metal salts and a first sodium ion-containing concentrate are obtained. The sodium salt rejection rate is 98%, and the fresh water recovery rate is 85%;

[0179] S3, in the first solidification reaction tank, the concentrated solution of the reaction product of calcium ions and the decalcifying agent discharged from the nanofiltration system in S2 is subjected to a first precipitation reaction with the phosphoric acid discharged from the first precipitant storage tank (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 10min, and a feed liquid containing calcium phosphate precipitate is generated; suction filtration is performed under a pressure of 0.35MPa to obtain a first recovered concentrated water and calcium phosphate solid residue, and the first recovered concentrated water is discharged to the second solidification reaction tank; in the second solidification reaction tank, the first recovered concentrated water (phosphate content is 5 80mg / L) is subjected to a second precipitation reaction with barium chloride flowing out of a second precipitant storage tank (the amount of barium chloride used is the theoretical amount of barium chloride when it completely reacts with the phosphate radical contained in the first recovered concentrated water), the reaction temperature is 20°C, the time is 20min, and a feed liquid containing barium phosphate precipitate is generated; a second solid-liquid separation is performed by a centrifuge at a speed of 3000r / min to obtain a second recovered concentrated water and a barium phosphate solid residue, and the second recovered concentrated water is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank; wherein the obtained calcium phosphate solid residue and barium phosphate solid residue are respectively washed, separated and dried to obtain a calcium phosphate product and a barium phosphate product, respectively, which specifically comprises the following steps:

[0180] Under normal temperature conditions, the calcium phosphate solid slag is washed with water in a calcium salt slag tank (based on the weight of the calcium phosphate solid slag, the amount of water is 120wt%), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water reaches 7; the water washing is stopped; suction filtration is performed under a pressure of -0.1MPa, and the separated calcium slag is dried at 190°C in a first drying system until the moisture 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 materials);

[0181] Under normal temperature conditions, the solid barium phosphate slag is washed with water in a barium salt slag tank (the weight of the solid barium phosphate slag is used as the basis, and the amount of water is 100wt%), allowed to stand for stratification, and the water washing is repeated until the pH value of the washing water is 6 and the water washing is stopped; the separated barium slag is allowed to stand for sedimentation and stratification under normal temperature and pressure conditions, and the separated barium slag is dried in a second drying system at 120° C. until the moisture content is less than or equal to 1wt%, to obtain a barium phosphate product (the purity of the barium phosphate is 95.7wt%, meeting the quality standard of precipitated barium phosphate);

[0182] S4. In the evaporation and condensation unit, the first sodium ion-containing concentrated solution obtained in S2 is evaporated and concentrated at 120° C., and condensed at 35° C. to obtain a second sodium ion-containing concentrated solution and evaporation condensate water. The obtained second sodium ion-containing concentrated solution (the sodium salt content is 13wt%, meeting the quality standard of brine drilling fluid) is placed in a brine storage tank; the evaporation condensate water, the second recovered concentrated water obtained in S3 and the fresh water without metal salt obtained in S2 are mixed in a hydrocarbon oil decalcifying agent aqueous solution tank, and the obtained recovered aqueous solution containing hydrocarbon oil decalcifying agent (phosphate content is 39mg / L) is returned to S1 for recycling.

[0183] Example 9

[0184] The hydrocarbon oil to be treated in this embodiment is super-heavy oil, and the metal ion contents are: calcium ion 2250 μg / g, magnesium ion 20.3 μg / g, and sodium ion 94.1 μg / g.

[0185] The following steps are used to remove metal ions from hydrocarbon oil:

[0186] S1, hydrocarbon oil decalcification agent (formic acid) and water are mixed (based on the weight of super heavy oil, the contents of hydrocarbon oil decalcification agent and water are 5wt% and 6wt%, respectively) to obtain a decalcification agent aqueous solution; at a temperature of 135° C. and a pressure of 1.5MPa, the decalcification agent aqueous solution is mixed with a membrane reactor made of a metal membrane with a pore size of 20μm for super heavy oil; then the oil-water mixture is placed in an electric desalting tank, and stays for 6min at a temperature of 135° C. and an electric field strength of 250V / cm, and then stays for 60min at a temperature of 135° C. and an electric field strength of 750V / cm; after oil-water separation, a demetallized hydrocarbon oil and a decalcification agent aqueous solution after reaction are obtained; analysis shows that the demetallized hydrocarbon oil has a calcium content of 32.8μg / g, a magnesium content of 4μg / g, and a sodium content of 1.9μg / g; the calcium content of the decalcification agent aqueous solution after reaction is 1.11wt%, and the sodium content is 0.046wt%;

[0187] S2. The decalcifying agent aqueous solution obtained after the reaction in S1 is pretreated by a microfiltration purification system (composed of a two-stage microfiltration system with filtration accuracy 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. The pretreated filtrate is sequentially sent to a primary nanofiltration system and a secondary nanofiltration system (both the two-stage nanofiltration systems 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 at a treatment pressure of 2 MPa. 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%, and the retention rate of sodium ions is 5%; the recovery rate of the filtrate is 75%. The obtained sodium ion-containing filtrate is sent to a reverse osmosis system (using a spiral reverse osmosis membrane made of polypiperazineamide) for reverse osmosis treatment. The operating pressure of the reverse osmosis system is 6 MPa, and fresh water without metal salts and a first sodium ion-containing concentrate are obtained. The sodium salt rejection rate is 90.5%, and the fresh water recovery rate is 75%;

[0188] S3, in the first solidification reaction tank, the concentrated solution of the reaction product of calcium ions and the decalcifying agent discharged from the nanofiltration system in S2 is subjected to a first precipitation reaction with the phosphoric acid discharged from the first precipitant storage tank (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 25min, and a feed liquid containing calcium phosphate precipitate is generated; suction filtration is performed under a pressure of -0.1MPa to obtain a first recovered concentrated water and calcium phosphate solid residue, and the first recovered concentrated water is discharged to the second solidification reaction tank; in the second solidification reaction tank, the first recovered concentrated water (phosphate content is 5 80mg / L) is subjected to a second precipitation reaction with barium chloride flowing out of a second precipitant storage tank (the amount of barium chloride used is the theoretical amount of barium chloride when it completely reacts with the phosphate radical contained in the first recovered concentrated water), the reaction temperature is 20°C, the time is 15min, and a feed liquid containing barium phosphate precipitate is generated; a second solid-liquid separation is performed by a centrifuge at a speed of 2500r / min to obtain a second recovered concentrated water and a barium phosphate solid residue, and the second recovered concentrated water is discharged into a hydrocarbon oil decalcifying agent aqueous solution tank; wherein the obtained calcium phosphate solid residue and barium phosphate solid residue are respectively washed, separated and dried to obtain a calcium phosphate product and a barium phosphate product, respectively, which specifically comprises the following steps:

[0189] At 40° C., washing the calcium phosphate solid slag in a calcium salt slag tank (with the weight of the calcium phosphate solid slag as the basis, the amount of water is 120wt%), standing for stratification, and repeatedly washing until the pH value of the washing water reaches 7; filtering under a pressure of -0.1MPa, and drying the separated calcium slag at 190° C. in a first drying system until the moisture 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 materials);

[0190] At 40° C., the solid barium phosphate slag is washed with water in a barium salt slag tank (the amount of water is 70wt% based on the weight of the solid barium phosphate slag), allowed to stand for stratification, and repeatedly washed with water until the pH value of the washing water reaches 6; the water washing is stopped when the pH value of the washing water reaches 6; the separated barium slag is allowed to stand for sedimentation and stratification at normal temperature and pressure, and the separated barium slag is dried in a second drying system at 120° C. until the moisture content is less than or equal to 1wt%, to obtain a barium phosphate product (the purity of the barium phosphate is 92.5wt%, meeting the quality standard of precipitated barium phosphate);

[0191] S4. In the evaporation and condensation unit, the first sodium ion-containing concentrated solution obtained in S2 is evaporated and concentrated at 120° C., and condensed at 50° C. to obtain a second sodium ion-containing concentrated solution and evaporation condensate water. The obtained second sodium ion-containing concentrated solution (the sodium salt content is 13wt%, meeting the quality standard of brine drilling fluid) is placed in a brine storage tank; the evaporation condensate water, the second recovered concentrated water obtained in S3 and the fresh water without metal salt obtained in S2 are mixed in a hydrocarbon oil decalcifying agent aqueous solution tank, and the obtained recovered aqueous solution containing hydrocarbon oil decalcifying agent (phosphate content is 39mg / L) is returned to S1 for recycling.

[0192] Example 10

[0193] The hydrocarbon oil was treated for metal ion removal according to the method of Example 8, except that the primary nanofiltration system used a tubular nanofiltration membrane made of cellulose acetate. Specifically, in S2, after the pre-treated filtrate was sent to the primary nanofiltration system and the secondary nanofiltration system for treatment, the retention rate of calcium and magnesium ions was 90.1%, and the retention rate of sodium ions was 2%; the recovery rate of the filtrate was 78%; the obtained sodium ion-containing filtrate was sent to the reverse osmosis system for reverse osmosis treatment, and the retention rate of sodium salt was 97.5%, and the recovery rate of fresh water was 82%.

[0194] Embodiment 11

[0195] The hydrocarbon oil was treated for metal ion removal according to the method of Example 8, except that the primary nanofiltration system used a rolled nanofiltration membrane made of aromatic polyamide. Specifically, in S2, after the pre-treated filtrate was sent to the primary nanofiltration system and the secondary nanofiltration system for treatment, the retention rate of calcium and magnesium ions was 87%, and the retention rate of sodium ions was 1%; the recovery rate of the filtrate was 80%; the obtained sodium ion-containing filtrate was sent to the reverse osmosis system for reverse osmosis treatment, and the retention rate of sodium salt was 98%, and the recovery rate of fresh water was 75%.

[0196] Example 12

[0197] The hydrocarbon oil was treated for metal ion removal according to the method of Example 8, except that the secondary nanofiltration system used a roll nanofiltration membrane made of cellulose acetate. Specifically, in S2, after the pre-treated filtrate was sent to the primary nanofiltration system and the secondary nanofiltration system for treatment, the retention rate of calcium and magnesium ions was 89%, and the retention rate of sodium ions was 1%; the recovery rate of the filtrate was 78%; the obtained sodium ion-containing filtrate was sent to the reverse osmosis system for reverse osmosis treatment, and the retention rate of sodium salt was 97%, and the recovery rate of fresh water was 80%.

[0198] Example 13

[0199] The hydrocarbon oil was treated for metal ion removal according to the method of Example 8, except that the secondary nanofiltration system used a tubular nanofiltration membrane made of aromatic polyamide. Specifically, in S2, after the pre-treated filtrate was sent to the primary nanofiltration system and the secondary nanofiltration system for treatment, the retention rate of calcium and magnesium ions was 80%, and the retention rate of sodium ions was 0%; the recovery rate of the filtrate was 85%; the obtained sodium ion-containing filtrate was sent to the reverse osmosis system for reverse osmosis treatment, the retention rate of sodium salt was 97%, and the recovery rate of fresh water was 68%.

[0200] Embodiment 14

[0201] The hydrocarbon oil was treated for metal ion removal according to the method of Example 8, except that a spiral reverse osmosis membrane made of sulfonated polysulfone was used for reverse osmosis treatment. Specifically, in S2, the obtained sodium ion-containing filtrate was sent to a reverse osmosis system for reverse osmosis treatment, and the sodium salt rejection rate was 94.5%, and the fresh water recovery rate was 70%.

[0202] Embodiment 15

[0203] The hydrocarbon oil is treated for metal ion removal according to the method of Example 8, except that a tubular reverse osmosis membrane made of polypiperazineamide is used for reverse osmosis treatment. Specifically, in S2, the obtained sodium ion-containing filtrate is sent to a reverse osmosis system for reverse osmosis treatment, and the sodium salt rejection rate is 95%, and the fresh water recovery rate is 75%.

[0204] Comparative Example 1

[0205] The hydrocarbon oil is treated for metal ion removal according to the method of Example 1, except that steps S2, S3 and S4 are not performed. The decalcifying agent aqueous solution obtained after the reaction in S1 is not subjected to membrane separation in S2. Since the reaction product of calcium ions and the decalcifying agent is not concentrated, the calcium concentration in the decalcifying agent aqueous solution after the reaction is too low to perform precipitation reaction, and the steps after S2 cannot be performed. The decalcifying agent produced after the hydrocarbon oil is demetallized cannot be recycled and can only be discharged, polluting the environment and causing waste.

[0206] Comparative Example 2

[0207] The hydrocarbon oil was treated with metal ions according to the method of Example 8, except that the step S2 was not performed. The decalcifying agent aqueous solution obtained after the reaction in S1 was not subjected to S2 membrane separation. 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 solidification reaction in S3 was 4 times that of Example 8. 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.

[0208] Test Case

[0209] The recovered aqueous solution containing hydrocarbon oil decalcifying agent obtained in each example was recycled 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.

[0210] Table 1

[0211]

[0212]

[0213]

[0214] Note: “ / ” indicates that the corresponding index does not need to be analyzed, and the 0th time indicates that the hydrocarbon oil is treated with the initially prepared decalcifying agent aqueous solution.

[0215] Examples 1-9 respectively carry out metal ion removal treatment on hydrocarbon oils with different metal ion contents. It can be seen from the results in Table 1 that 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 decalcifying agent aqueous solution), indicating that the recycling of hydrocarbon oil decalcifying agent and the resource utilization of decalcification wastewater can be well realized. 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 mgNacl / L after electrical desalting, and if it is greater than 5 mgNacl / 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.

[0216] In addition, Examples 10-13 respectively change the material and form of the nanofiltration membrane in the primary nanofiltration system and the secondary nanofiltration system. Compared with Example 8, the retention rate of calcium and magnesium ions in the nanofiltration system in Examples 10-13 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, more calcium and magnesium ions enter the reverse osmosis system, and the processing load of the reverse osmosis membrane is increased. These calcium and magnesium ions eventually enter the S4 stage. There is a risk of equipment scaling in the S4 stage, which reduces the evaporation amount and increases the difficulty of processing. Examples 14 and 15 respectively change the material and form of the reverse osmosis membrane in the reverse osmosis system. Compared with Example 8, the fresh water recovery rate of the reverse osmosis system in Examples 14 and 15 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 S4 stage is increased.

[0217] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for removing metal ions from hydrocarbon oil, characterized in that: The method comprises the following steps: S1, subjecting the hydrocarbon oil and the decalcifying agent aqueous solution to an electrical desalting treatment to obtain a demetallized hydrocarbon oil and a reacted decalcifying agent aqueous solution; S2, subjecting the decalcifying agent aqueous solution after the reaction to membrane separation to obtain a concentrated solution of the reaction product of calcium ions and the decalcifying agent, a first concentrated solution containing sodium ions, and fresh water; S3, decalcifying the concentrated solution of the reaction product of the calcium ions and the decalcifying agent to obtain a decalcified concentrated solution of the decalcifying agent; S4, evaporating and condensing the first sodium ion-containing concentrated solution to obtain a second sodium ion-containing concentrated solution and condensed water; mixing the decalcified decalcifying agent concentrated solution, the fresh water and the condensed water and returning the mixture to S1.

2. The method according to claim 1, characterized in that In S3, the decalcification method includes: mixing the concentrated solution of the reaction product of the calcium ions and the decalcifying agent with a first precipitant to perform a first precipitation reaction, and then performing a first solid-liquid separation; mixing the obtained liquid phase product with a second precipitant to perform a second precipitation reaction, and performing a second solid-liquid separation to obtain the decalcified decalcifying agent concentrated solution; Preferably, the first precipitant is sulfuric acid or phosphoric acid; Preferably, the temperature of the first precipitation reaction is 20-50°C and the time is 5-30min; Preferably, the second precipitant is barium chloride, barium hydroxide or barium acetate; Preferably, the temperature of the second precipitation reaction is 20-50°C and the time is 5-30 minutes.

3. The method according to claim 1 or 2, characterized in that: In S1, based on the weight of the hydrocarbon oil, the contents of the decalcifying agent and water in the decalcifying agent aqueous solution are 0.01-5wt% and 1-25wt%, respectively; Preferably, the decalcifying agent is selected from at least one of formic acid, acetic acid, propionic acid and butyric acid; Preferably, the process of the electrical desalination treatment comprises: mixing the hydrocarbon oil and the decalcifying agent aqueous solution at a temperature of 50-150°C and a pressure of 0.02-1MPa, then leaving the mixture at an electric field strength of 50-500V / cm for 1-60min, and then leaving the mixture at an electric field strength of 500-1500V / cm for 5-200min.

4. The method according to any one of claims 1 to 3, characterized in that: In S2, the membrane separation process comprises: subjecting the decalcifying agent aqueous solution after the reaction to at least one stage of nanofiltration treatment, preferably two stages, to obtain a concentrated solution and a filtrate of the reaction product of the calcium ions and the decalcifying agent, and then subjecting the filtrate to at least one stage of reverse osmosis treatment, preferably one stage, through a reverse osmosis membrane to obtain the first sodium ion-containing concentrated solution and the fresh water; Preferably, the pressure of the nanofiltration treatment is 0.2-2 MPa; Preferably, the nanofiltration membrane is selected from a monovalent ion selective permeable nanofiltration membrane; Preferably, the material of the nanofiltration membrane is selected from at least one of aromatic polyamide, polypiperazineamide, cellulose acetate and sulfonated polyethersulfone, preferably aromatic polyamide; Preferably, the pressure of the reverse osmosis treatment is 2-6 MPa; Preferably, the material of the reverse osmosis membrane is selected from at least one of aromatic polyamide, polypiperazineamide, polyimide and sulfonated polysulfone, preferably polypiperazineamide.

5. The method according to claim 4, characterized in that The membrane separation process further comprises: pre-treating the decalcification agent aqueous solution after the reaction, and then performing the nanofiltration treatment; Preferably, the pretreatment method comprises: subjecting the reacted decalcifying agent aqueous solution to microfiltration through a microfiltration membrane; Preferably, the material of the microfiltration membrane is selected from at least one of ceramic, polypropylene, polycarbonate, polyvinyl chloride, polysulfone, polyvinylidene fluoride and polytetrafluoroethylene.

6. The method according to any one of claims 1 to 5, characterized in that: In S4, the evaporation temperature is 120-200°C, and the condensation temperature is 20-50°C; Preferably, the content of sodium salt in the second sodium ion-containing concentrated solution is 10-30 wt%.

7. The method according to any one of claims 2 to 6, characterized in that: The method further comprises: washing, separating slag and drying the solid phase product obtained by the first precipitation reaction to obtain a calcium salt product; Preferably, the method further comprises: washing, slagging and drying the solid phase product obtained by the second precipitation reaction to obtain a barium salt product.

8. A device for removing metal ions from hydrocarbon oil, characterized in that: The device comprises: An electrical desalting unit, used for conducting electrical desalting treatment on hydrocarbon oil and decalcifying agent aqueous solution to remove metal ions in the hydrocarbon oil; A membrane separation unit, used for performing membrane separation on the water phase flowing out of the electrical desalination unit; an evaporation and condensation unit, used for evaporating and concentrating the sodium ion-containing concentrated liquid flowing out of the membrane separation unit, and condensing the obtained gas phase product into condensed water; The decalcification treatment unit is used to decalcify the concentrated solution of the reaction product of calcium ions and decalcification agent flowing out of the membrane separation unit, and mix the obtained liquid phase product, the fresh water flowing out of the membrane separation unit and the condensed water flowing out of the evaporation and condensation unit and return them to the electrical desalination unit.

9. The device according to claim 8, characterized in that The electric desalination unit comprises a mixer and an electric desalination tank which are connected to each other; Preferably, the membrane separation unit comprises: a nanofiltration system for subjecting the aqueous phase flowing out of the electrical desalination unit to nanofiltration treatment; a reverse osmosis system for subjecting the filtrate flowing out of the nanofiltration system to reverse osmosis treatment; Preferably, the membrane separation unit further comprises a microfiltration purification system for removing suspended matter and sediment from the water phase flowing out of the electrical desalination unit and feeding the water phase into the nanofiltration system; Preferably, the evaporation-condensation unit comprises an evaporator and a condenser connected to each other.

10. The device according to claim 9, characterized in that The decalcification processing unit comprises: A first solidification reaction tank is used to mix the concentrated solution of the reaction product of the calcium ions and the decalcifying agent flowing out of the nanofiltration system with a first precipitant to perform a first precipitation reaction; A first solid-liquid separator, used for performing a first solid-liquid separation on the liquid flowing out of the first solidification reaction tank; A second solidification reaction tank is used to mix the liquid product flowing out of the first solid-liquid separator with a second precipitant to perform a second precipitation reaction; The second solid-liquid separator is used to perform a second solid-liquid separation on the material flowing out of the second solidification reaction tank, and the obtained liquid phase product, the condensed water flowing out of the condenser and the fresh water flowing out of the reverse osmosis system are mixed through a hydrocarbon oil decalcifying agent aqueous solution tank and then flow into the mixer.

11. The device according to claim 10, characterized in that The decalcification treatment unit also includes: a first drying system for drying the solid phase product flowing out of the first solid-liquid separator to obtain a calcium salt product; and a second drying system for drying the solid phase product flowing out of the second solid-liquid separator to obtain a barium salt product.

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