A treatment system and method for naphthenic acid alkali slag wastewater

Abstract

The invention discloses a system and method for treating cyclopentane acid alkali slag wastewater; the treatment system comprises: a first reactor, which is used for mixing and stirring alkali slag wastewater, process water and excess organic extractant under heating conditions to obtain a first mixed liquid; and the first mixed liquid is transported to a first separation unit; the first separation unit is used for separating and treating the first mixed liquid to obtain neutral oil and separated liquid; and the separated liquid is sent to a second reactor; a second reactor, which is used for mixing and reacting sulfuric acid, organic extractant and separated liquid under heating conditions to obtain a second mixed liquid; and the second mixed liquid is transported to a second separation unit; the second separation unit is used for separating and treating the second mixed liquid to obtain cyclopentane acid; therefore, based on the system of the application, cyclopentane acid can be effectively extracted from cyclopentane acid alkali slag wastewater under normal pressure, the purity of cyclopentane acid extraction is improved, and the cyclopentane acid alkali slag wastewater can be discharged normally.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum production, and in particular relates to a system and method for treating naphthenic acid and alkali slag wastewater. Background Art

[0002] Cycloalkane acid is an acidic compound existing in petroleum, so it is also called petroleum acid. It is a dark brown oily liquid. Cycloalkane acid is a carboxyl derivative of cycloalkanes, has a special smell, is almost insoluble in water, but easily soluble in petroleum ether, ethanol, benzene and hydrocarbons. The upstream industry of cycloalkane acid mainly extracts cycloalkane acid from raw materials such as naphthalene or crude oil, and the downstream industry of cycloalkane acid mainly uses cycloalkane acid to make paint catalysts or wood preservatives. Due to the rising prices of raw materials in the upstream of the cycloalkane acid industry and the difficulty of the production technology for extracting cycloalkane acid, there are few large-scale cycloalkane acid production enterprises in China. At present, due to the continuous improvement of my country's cycloalkane acid production capacity and the oversupply of the cycloalkane acid market, in order to promote the development of cycloalkane acid, my country actively encourages the development of the downstream industry of cycloalkane acid, thereby driving the rapid development of the cycloalkane acid industry.

[0003] Due to the different origins, properties, and compositions of petroleum, the content of cyclohexane acid in petroleum is also different. Usually, the content of cyclohexane acid in petroleum is about 1%, but it can be as high as 2-3%. Since cyclohexane acid is consistent with the corresponding crude oil products due to its molecular composition and boiling point range, and has good oil solubility, it is difficult to obtain cyclohexane acid from petroleum using the usual distillation method. However, since cyclohexane acid exists in petroleum, it seriously corrodes the equipment of the refinery, thereby affecting the refining cycle of the oil, and further affecting the improvement of the efficiency of the refinery. If petroleum products contain cyclohexane acid, it will cause corrosion of oil-using equipment, affect the efficiency of the use of tens of millions of enterprises, and cause corrosion losses that should not occur.

[0004] In the prior art, in order to prevent cyclohexane acid from corroding oil refining equipment, oil refineries usually use alkali washing of petroleum products, but this will produce a large amount of alkali residue wastewater, in which the chemical oxygen demand (COD), neutral oil, salt content, and phenolic substances are relatively high; if the alkali residue wastewater is directly discharged into the environment, it will seriously pollute the environment; if the alkali residue wastewater is directly sent to a sewage treatment plant, it will also seriously affect the normal operation of the sewage treatment plant, and it is difficult to treat it to meet the standards. In addition, in this way, precious cyclohexane acid is also wasted as waste residue in the refinery, causing huge economic losses. For refineries, the problem of treating alkali residue wastewater is common, so the development and utilization of technology for recycling cyclohexane acid from alkali residue wastewater in refineries has very important economic, environmental and social significance, and can also obtain obvious economic, environmental and social benefits. Summary of the invention

[0005] The invention provides a treatment system and a treatment method for naphthenic acid alkali slag wastewater. The treatment system can effectively extract naphthenic acid from the naphthenic acid alkali slag wastewater and improve the purity of the extracted naphthenic acid.

[0006] To achieve the above-mentioned purpose, according to a first aspect of an embodiment of the present application, a treatment system for cyclopentane acid alkali slag wastewater is provided, the treatment system comprising: a first reactor, used for mixing and stirring alkali slag wastewater, process water and excess organic extractant under heating conditions to obtain a first mixed liquid; and conveying the first mixed liquid to a first separation unit; the alkali slag wastewater comprises at least sodium cyclopentaneate, neutral oil, water and impurities; the first separation unit is used for separating and treating the first mixed liquid to obtain neutral oil and separated liquid; and sending the separated liquid to a second reactor; the second reactor is used for mixing and reacting sulfuric acid, an organic extractant and the separated liquid under heating conditions to obtain a second mixed liquid; and conveying the second mixed liquid to a second separation unit; the second separation unit is used for separating and treating the second mixed liquid to obtain cyclopentane acid.

[0007] To achieve the above-mentioned purpose, according to the second aspect of the embodiment of the present application, a method for treating cyclopentane acid alkali slag wastewater is further provided, the method comprising: adding alkali slag wastewater, process water and excess organic extractant into a first reactor, and fully stirring at 45-65°C to obtain a first mixed liquid; then the first reactor transports the first mixed liquid to a first phase separation tank; wherein the alkali slag wastewater comprises at least sodium cyclopentaneate, neutral oil, water and impurities; the first phase separation tank performs static phase separation on the first mixed liquid at 45-65°C for 8-15h to obtain a first upper phase material and a first lower phase material; then The first phase separation tank sends the first lower phase material to the second distillation tower, and sends the first upper phase material to the second reactor; the second distillation tower performs distillation separation on the first lower phase material to obtain neutral oil and dichloromethane respectively; sulfuric acid and an organic extractant are added to the second reactor; then the sulfuric acid, the organic extractant and the first upper phase material react in the second reactor at 30-40° C. for 0.1-1h to obtain a second mixed liquid; then the second reactor transports the second mixed liquid to the second separation unit; the second separation unit performs separation treatment on the second mixed liquid to obtain cyclohexane acid.

[0008] Compared with the prior art, the embodiment of the present invention provides a treatment system and method for cyclopentane acid alkali slag wastewater; the treatment system comprises: a first reactor, used for mixing and stirring alkali slag wastewater, process water and excess organic extractant under heating conditions to obtain a first mixed liquid; and conveying the first mixed liquid to a first separation unit; the alkali slag wastewater comprises at least sodium cyclopentaneate, neutral oil, water and impurities; the first separation unit is used for separating and treating the first mixed liquid to obtain neutral oil and separated liquid; and sending the separated liquid to a second reactor; the second reactor is used for mixing and reacting sulfuric acid, an organic extractant and the separated liquid under heating conditions to obtain a second mixed liquid; and conveying the second mixed liquid to a second separation unit; the second separation unit is used for separating and treating the second mixed liquid to obtain cyclopentane acid. In this embodiment, the neutral oil in the alkali residue wastewater is fully dissolved in the organic extractant through the first reactor, and then the neutral oil is separated from the first mixed liquid by the first separation unit; then the sodium cyclopentaneate in the alkali residue wastewater is replaced by sulfuric acid in the second reactor, and the replaced cyclopentaneate is fully dissolved in the organic extractant; finally, the cyclopentaneate is separated from the second mixed liquid by the second separation unit; thus, based on the system of the present application, cyclopentaneate can be effectively extracted from cyclopentaneate alkali residue wastewater under normal pressure, and the purity of cyclopentaneate extraction is improved, so that the cyclopentaneate alkali residue wastewater can be discharged normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0010] Figure 1 A schematic diagram of the structure of a system for treating cyclopentane acid alkali slag wastewater provided by one embodiment of the present invention;

[0011] Figure 2 A schematic structural diagram of a system for treating cyclopentane acid alkali slag wastewater provided in another embodiment of the present invention;

[0012] Figure 3 A schematic flow chart of a method for treating cyclopentane acid alkali slag wastewater provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0013] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0014] like Figure 1 1 is a schematic diagram of the structure of a system for treating cyclopentane acid alkali slag wastewater provided by one embodiment of the present invention.

[0015] A system for treating cyclopentane acid alkali slag wastewater, the system comprising: a first reactor, used for mixing and stirring alkali slag wastewater, process water and excess organic extractant under heating conditions to obtain a first mixed liquid; and conveying the first mixed liquid to a first separation unit; the alkali slag wastewater at least comprises sodium cyclopentaneate, neutral oil, water and impurities; the first separation unit is used for separating and treating the first mixed liquid to obtain neutral oil and separated liquid; and conveying the separated liquid to a second reactor; the second reactor is used for mixing and reacting sulfuric acid, an organic extractant and the separated liquid under heating conditions to obtain a second mixed liquid; and conveying the second mixed liquid to a second separation unit; the second separation unit is used for separating and treating the second mixed liquid to obtain cyclopentane acid.

[0016] Specifically, mixing and stirring the mixed liquid in the first reactor under heating conditions can fully dissolve the neutral oil in the alkali residue wastewater into the organic extractant, thereby facilitating the extraction of the neutral oil in the alkali residue wastewater. Mixing and reacting the mixed liquid in the second reactor under heating conditions is conducive to the rapid reaction between sodium cyclopentaneate and sulfuric acid, and enables the generated cyclopentane acid to be fully dissolved in the organic extractant.

[0017] Here, there is no limitation on the first separation unit and the second separation unit, as long as they can separate and process to obtain neutral oil and cyclohexane acid. For example, cyclohexane acid can be obtained by first phase separation and then distillation separation.

[0018] In this embodiment, neutral oil is first separated from the alkali residue wastewater using the first reactor and the first separation unit; and then cyclopentane acid is separated from the alkali residue wastewater using the second reactor and the second separation unit; thus, cyclopentane acid can be effectively extracted from cyclopentane acid alkali residue wastewater under normal pressure, and the purity of cyclopentane acid extraction is improved, so that the cyclopentane acid alkali residue wastewater can be discharged normally. In addition, this embodiment uses an excessive amount of organic extractant for extraction, so that the neutral oil in the alkali residue wastewater can be completely separated, thereby improving the purity of subsequent cyclopentane acid extraction.

[0019] In a preferred embodiment, the first separation unit includes a first phase separation tank and a second distillation tower; the first phase separation tank is used to receive the first mixed liquid and then perform phase separation on the first mixed liquid under heating conditions to obtain a first upper phase material and a first lower phase material; the first lower phase material is transported to the second distillation tower, and the first upper phase material is transported to the second reactor; the second distillation tower is used to perform distillation separation on the first lower phase material, and the organic extractant is output from the top of the tower and the neutral oil is output from the bottom of the tower. In this embodiment, the water phase and the organic extractant phase containing the neutral oil are first fully separated by the first phase separation tank; then the neutral oil and the organic extractant phase are separated by the second distillation tower, thereby obtaining a neutral oil byproduct and an organic extractant, respectively.

[0020] In a preferred embodiment, the second separation unit includes: a second phase separation tank, a first distillation tower and a sub-separation unit; the second phase separation tank is used to receive the second mixed liquid and then perform phase separation on the second mixed liquid to obtain a second upper phase material and a second lower phase material; the second upper phase material is transported to the separation unit, and the second lower phase material is transported to the first distillation tower; the first distillation tower is used to perform distillation separation on the second lower phase material, and the organic extractant is output from the top of the tower and cyclohexane acid is output from the bottom of the tower; the sub-separation unit is used to separate and treat the second upper phase material to obtain sodium sulfate wastewater and cyclohexane acid. In this embodiment, the aqueous phase containing sodium sulfate and the organic extractant phase containing cyclohexane acid are fully phase-separated by the second phase separation tank; then the organic extractant is separated from the cyclohexane acid by the first distillation tower to obtain a cyclohexane acid product; finally, the cyclohexane acid is further extracted by the sub-separation unit; thus, the cyclohexane acid in the alkali residue wastewater can be effectively extracted, and the purity of the cyclohexane acid extraction is improved.

[0021] In a preferred embodiment, the sub-separation unit includes: an extraction tower and a third distillation tower; the extraction tower is used to countercurrently extract the organic extractant input from the top of the tower with the second upper phase material input from the bottom of the tower; and the third upper phase material obtained by extraction is transported to the third distillation tower, and the third lower phase material obtained by extraction is transported to the first distillation tower; the third distillation tower is used to distill and separate the third upper phase material, output the organic extractant from the top of the tower and output sodium sulfate wastewater from the bottom of the tower; the first distillation tower is also used to distill and separate the third lower phase material, output the organic extractant from the top of the tower and output cyclopentane acid from the bottom of the tower. This embodiment uses the organic extractant in the extraction tower to perform multi-stage extraction on the aqueous phase, thereby ensuring the recovery rate of cyclopentane acid, and further improving the extraction rate of cyclopentane acid in the alkali slag wastewater. The organic extractant is separated from the wastewater by the third distillation tower, and the organic matter content in the wastewater is reduced, so that the treated alkali slag wastewater can be discharged normally, reducing pollution to the environment.

[0022] In a preferred embodiment, the sub-separation unit further includes a first filter; the first filter is arranged before the extraction tower, and is used to filter the second upper phase material after receiving the second upper phase material output by the second phase separation tank, and transport the filtered first filtrate to the extraction tower. In this embodiment, impurities in the water phase are filtered by the first filter, and the filtered water phase is then extracted, thereby improving the purity of the cyclohexane acid extraction, which is beneficial to the discharge of alkali residue wastewater.

[0023] In a preferred embodiment, the sub-separation unit further includes a second filter; the second filter is arranged before the first distillation tower, and is used to filter the second lower phase material of the second phase separation tank and the third lower phase material of the extraction tower after receiving the second lower phase material of the second phase separation tank and the third lower phase material of the extraction tower, and transport the filtered second filtrate to the first distillation tower. Thus, the impurities in the second phase separation tank and the dichloromethane phase of the extraction tower are filtered by the second filter, thereby improving the purity of the cyclopentane acid extraction.

[0024] In a preferred embodiment, the organic extractant is dichloromethane, petroleum ether or ethylene dichloride.

[0025] The organic extractant obtained in this embodiment can be recycled, so when the system is running, it is only necessary to regularly replenish the small amount of organic extractant lost.

[0026] like Figure 3 FIG. 1 is a flow chart of a method for treating cyclopentane acid alkali slag wastewater provided by an embodiment of the present invention. A method for treating cyclopentane acid alkali slag wastewater comprises at least the following steps:

[0027] S301, adding alkali residue wastewater, process water and excess organic extractant to the first reactor, and fully stirring at 45-65° C. to obtain a first mixed liquid; then the first reactor transports the first mixed liquid to a first phase separation tank; wherein the alkali residue wastewater includes at least sodium cyclopentaneate, neutral oil, water and impurities;

[0028] S302, the first phase separation tank performs static phase separation on the first mixed liquid at 45-65° C. for 8-15 hours to obtain a first upper phase material and a first lower phase material; then the first phase separation tank sends the first lower phase material to the second distillation tower, and sends the first upper phase material to the second reactor;

[0029] S303, a second distillation tower performs distillation separation on the first lower phase material to obtain neutral oil and an organic extractant respectively;

[0030] S304, adding sulfuric acid and an organic extractant to the second reactor; then the sulfuric acid, the organic extractant and the first upper phase material react in the second reactor at 30-40° C. for 0.1-1 h to obtain a second mixed solution; then the second reactor transports the second mixed solution to a second separation unit;

[0031] S305, the second separation unit separates the second mixed liquid to obtain cyclohexane acid.

[0032] In a preferred embodiment, the second separation unit comprises: a second phase separation tank, a first filter, a second filter, an extraction tower, a first distillation tower, and a third distillation tower; the second separation unit separates and processes the second mixed liquid to obtain cyclohexane acid; the second reactor transports the second mixed liquid to the second phase separation tank; then the second phase separation tank performs phase separation on the second mixed liquid to obtain a second upper phase material and a second lower phase material; then the second phase separation tank transports the second upper phase material to the first filter, and transports the second lower phase material to the second filter; the first filter filters the second upper phase material to obtain impurities and a first filtrate, respectively; then The first filter transports the first filtrate to an extraction tower; the extraction tower uses an organic extractant to perform reverse extraction on the first filtrate to obtain a third upper phase material and a third lower phase material; then the extraction tower transports the third upper phase material to a third distillation tower, and transports the third lower phase material to a second filter; the third distillation tower performs distillation separation on the third upper phase material to obtain dichloromethane and sodium sulfate wastewater respectively; the second filter performs filtering treatment on the second lower phase material and the third lower phase material to obtain impurities and a second filtrate; then the second filter transports the second filtrate to the first distillation tower; the first distillation tower performs distillation separation on the second filtrate to obtain cyclohexane acid.

[0033] like Figure 2 , which is a schematic structural diagram of a system for treating cyclopentane acid alkali slag wastewater provided by another embodiment of the present invention.

[0034] A system for treating naphthenic acid and alkali slag wastewater, comprising at least:

[0035] The first reactor is used to mix and stir the alkali residue wastewater, process water and excess organic extractant under heating conditions to obtain a first mixed liquid; and transport the first mixed liquid to a first phase separation tank; the alkali residue wastewater includes at least sodium cyclopentaneate, neutral oil, water and impurities;

[0036] The first phase separation tank is used to receive the first mixed liquid and then perform phase separation on the first mixed liquid under heating conditions to obtain a first upper phase material and a first lower phase material; transport the first lower phase material to the second distillation tower; and transport the first upper phase material to the second reactor;

[0037] The second distillation tower is used to distill and separate the first lower phase material, output the organic extractant at the top of the tower and output the neutral oil at the bottom of the tower;

[0038] The second reactor is used to mix and react sulfuric acid, an organic extractant and the separation liquid under heating conditions to obtain a second mixed liquid; and to transport the second mixed liquid to a second phase separation tank;

[0039] The second phase separation tank is used to perform phase separation on the second mixed liquid to obtain a second upper phase material and a second lower phase material; and to transport the second upper phase material to the first filter, and to transport the second lower phase material to the second filter;

[0040] The first filter is used to filter the second upper phase material and transport the filtered first filtrate to the extraction tower. The extraction tower is used to countercurrently extract the organic extractant input from the top of the tower with the second upper phase material input from the bottom of the tower; and transport the third upper phase material obtained by extraction to the third distillation tower, and transport the third lower phase material obtained by extraction to the second filter;

[0041] The third distillation tower is used to distill and separate the third upper phase material, output the organic extractant at the top of the tower and output the sodium sulfate wastewater at the bottom of the tower;

[0042] The second filter performs filtering treatment on the second lower phase material and the third lower phase raw material, and transmits the filtered second filtrate to the first distillation tower.

[0043] The first distillation tower is also used to distill and separate the second lower phase material and the third lower phase material, and the organic extractant is output from the top of the tower and the cyclohexane acid is output from the bottom of the tower.

[0044] Specifically, the input end of the first reactor is used to add alkali residue waste water, process water and dichloromethane; the output end of the first reactor is connected to the first phase-separation tank; the first output end of the first phase-separation tank is connected to the first input end of the second reactor, and the second output end of the first phase-separation tank is connected to the second distillation tower; the second input end of the second reactor is used to add organic extractant and sulfuric acid; the output end of the second reactor is connected to the input end of the second phase-separation tank; the first output end of the second phase-separation tank is connected to the first filter, and the second output end of the second phase-separation tank is connected to the first input end of the second filter; the first output end of the first filter is connected to the first input end of the extraction tower The first input end of the extraction tower is connected to the second input end of the second filter; the second output end of the first filter is used to discharge impurities; the second input end of the extraction tower is used to input an organic extractant; the first output end of the extraction tower is connected to the input end of the third distillation tower, and the first output end of the third distillation tower is used to discharge the organic extractant; the second output end of the third distillation tower is used to discharge sodium sulfate wastewater; the second output end of the extraction tower is connected to the second input end of the second filter; the first output end of the second filter is used to discharge impurities; the second output end of the second filter is connected to the input end of the first distillation tower, the first output end of the first distillation tower is used to discharge cyclohexane acid, and the second output end is used to discharge the organic extractant.

[0045] For example, a method for treating cyclopentane acid alkali slag wastewater comprises at least the following steps:

[0046] (1) 1000 kg of alkali residue waste water (containing 260.7 kg of sodium cyclohexaneate, 105 kg of neutral oil, 604.3 kg of water, and 30 kg of impurities), 1000 kg of process water, and 1000 kg of dichloromethane were added to the first reactor respectively; the temperature in the first reactor was controlled to 50° C., and the reaction was stirred for 0.5 hours;

[0047] (2) The first mixed liquid (containing 260.7 kg of sodium cyclohexaneate, 105 kg of oil, 1604.3 kg of water, 1000 kg of dichloromethane, and 30 kg of impurities) after the reaction in the first reactor was transported to the first phase separation tank, the temperature of the first phase separation tank was controlled at 50° C., and then the mixture was allowed to stand for 12 hours for phase separation;

[0048] (3) The first lower phase material (containing 105 kg of oil and 781 kg of dichloromethane) from the first phase separation tank is transported to the second distillation tower for distillation separation. 781 kg of dichloromethane is recycled from the top of the tower, and 105 kg of oil is sold as a by-product from the bottom of the tower;

[0049] (4) The first upper phase material (comprising 260.7 kg of sodium cyclopentaneate, 1604.3 kg of water, 219 kg of dichloromethane, and 30 kg of impurities) from the first phase separation tank, 500 kg of dichloromethane, and 250 kg of 30% by weight dilute sulfuric acid were introduced into the second reactor; the temperature of the second reactor was then maintained at 35° C. and the reaction was carried out for 0.5 hours; at this time, the sodium cyclopentaneate was converted into cyclopentane acid, the generated sodium sulfate was dissolved in the water phase, and the cyclopentane acid was dissolved in the dichloromethane;

[0050] (5) The second mixed liquid (containing 227 kg of cyclohexane acid, 1779.4 kg of water, 719 kg of dichloromethane, 108.6 kg of sodium sulfate, and 30 kg of impurities) produced from the second reactor was transported to the second phase separation tank for phase separation;

[0051] (6) The second upper phase output from the second phase separation tank (containing 28 kg of cyclohexane acid, 1779.4 kg of water, 30 kg of impurities, and 108.6 kg of sodium sulfate) is transported to the first filter to remove some impurities;

[0052] (7) The discharge material (containing 28 kg of cyclohexane acid, 1779.4 kg of water, 15 kg of impurities, and 108.6 kg of sodium sulfate) from which some impurities are removed by the first filter still contains a small amount of cyclohexane acid, which enters the bottom of the extraction tower and is extracted and recovered by countercurrent contact with 500 kg of dichloromethane entering from the top of the extraction tower;

[0053] (8) The third upper phase material (containing 1779.4 kg of water, 108.6 kg of sodium sulfate and a small amount of 38 kg of dichloromethane) coming out from the top of the extraction tower enters the middle of the third distillation tower, and after distillation and separation, 38 kg of dichloromethane is extracted from the top of the third distillation tower for recycling; the bottom of the tower contains 1888 kg of wastewater containing sodium sulfate, which needs to be treated;

[0054] (9) The second lower phase material (containing 199 kg of cyclohexane acid and 719 kg of dichloromethane) from the second phase separation tank and the third lower phase material (containing 28 kg of cyclohexane acid, 462 kg of dichloromethane and 15 kg of impurities) from the bottom of the extraction tower were collected into a second filter to remove impurities;

[0055] (10) The output from the second filter after impurities are removed enters the middle of the first distillation tower. After distillation and separation, 1181 kg of dichloromethane is extracted from the top of the first distillation tower for recycling; 227 kg of cyclohexane acid product is extracted from the bottom of the tower for sale.

[0056] This application is based on the treatment of 1000kg of alkali residue waste liquid, and the materials used are as follows: 1000kg of alkali residue waste water; 2000kg of dichloromethane (can be recycled); 250kg of 30% sulfuric acid; 1000kg of process water; the extracted materials are as follows: 227kg of cyclohexane acid; 105kg of neutral oil; 1880kg of sodium sulfate waste water; impurities: 30kg.

[0057] Based on the SH / T0530-92 standard of the petrochemical industry of the People's Republic of China, the cyclohexane acid recovered by the treatment method of this application was sampled and tested, and the test results are shown in Table 1 below:

[0058] Table 1 Indices of cyclohexane acid obtained based on the treatment method of this application

[0059]

[0060] The treatment method of this embodiment adopts two-stage phase separation; first, the water phase and the dichloromethane phase containing neutral oil are fully separated by the first stage phase separation; then, the water phase containing sodium sulfate and the dichloromethane phase containing cyclopentane acid are fully separated by the second stage phase separation; thereby, cyclopentane acid can be effectively extracted from the cyclopentane acid alkali slag wastewater, and the purity of the extracted cyclopentane acid is improved.

[0061] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0062] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0063] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0064] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0065] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

[0066] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0067] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0068] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A system for treating naphthenic acid and alkali slag wastewater, characterized in that: include: The first reactor is used to mix and stir the alkali residue wastewater, process water and excess organic extractant under heating conditions to obtain a first mixed liquid; and transport the first mixed liquid to a first separation unit; the alkali residue wastewater includes at least sodium cyclopentaneate, neutral oil, water and impurities; The first separation unit is used to separate the first mixed liquid to obtain neutral oil and separated liquid; and sending the separated liquid to a second reactor; The second reactor is used to mix and react sulfuric acid, an organic extractant and the separation liquid under heating conditions to obtain a second mixed liquid; and to transport the second mixed liquid to a second separation unit; The second separation unit is used to separate the second mixed liquid to obtain cyclohexane acid; The second separation unit comprises: a second phase separation tank, a first distillation tower and a sub-separation unit; The second phase separation tank is used to receive the second mixed liquid and then perform phase separation on the second mixed liquid to obtain a second upper phase material and a second lower phase material; transport the second upper phase material to the sub-separation unit, and transport the second lower phase material to the first distillation tower; The first distillation tower is used to distill and separate the second lower phase material, outputting an organic extractant at the top of the tower and outputting cyclohexane acid at the bottom of the tower; The sub-separation unit is used to separate and process the second upper phase material to obtain sodium sulfate wastewater and cyclohexane acid; The sub-separation unit comprises: an extraction tower and a third distillation tower; The extraction tower is used to countercurrently extract the organic extractant input from the top of the tower with the second upper phase material input from the bottom of the tower; and to transport the third upper phase material obtained by extraction to the third distillation tower, and to transport the third lower phase material obtained by extraction to the second filter; The third distillation tower is used to distill and separate the third upper phase material, output the organic extractant at the top of the tower and output the sodium sulfate wastewater at the bottom of the tower; The first distillation tower is also used to distill and separate the third lower phase material, outputting an organic extractant at the top of the tower and outputting cyclohexane acid at the bottom of the tower.

2. The system according to claim 1, characterized in that The first separation unit comprises a first phase separation tank and a second distillation tower; The first phase separation tank is used to receive the first mixed liquid and perform phase separation on the first mixed liquid under heating conditions to obtain a first upper phase material and a first lower phase material; and to transport the first lower phase material to the second distillation tower, and to transport the first upper phase material to the second reactor; The second distillation tower is used to distill and separate the first lower phase material, output the organic extractant at the top of the tower and output the neutral oil at the bottom of the tower.

3. The system according to claim 2, characterized in that The sub-separation unit further comprises a first filter; The first filter is arranged before the extraction tower, and is used for filtering the second upper phase material after receiving the second upper phase material output by the second phase separation tank, and conveying the filtered first filtrate to the extraction tower.

4. The system according to claim 3, characterized in that The sub-separation unit further includes a second filter; The second filter is arranged before the first distillation tower, and is used for filtering the second lower phase material and the third lower phase material of the second phase separation tank and the third lower phase material of the extraction tower after receiving them, and conveying the second filtrate after filtration to the first distillation tower.

5. The system according to claim 1, characterized in that The organic extractant is dichloromethane, neutral oil ether or dichloroethane.

6. A method for treating naphthenic acid alkali slag wastewater, characterized in that: Adding alkali residue wastewater, process water and excess organic extractant into the first reactor, stirring them fully at 45-65° C. to obtain a first mixed liquid; then the first reactor transports the first mixed liquid to a first phase separation tank; wherein the alkali residue wastewater includes at least sodium cyclopentaneate, neutral oil, water and impurities; The first phase separation tank performs static phase separation on the first mixed liquid at 45-65° C. for 8-15 hours to obtain a first upper phase material and a first lower phase material; then the first phase separation tank sends the first lower phase material to a second distillation tower, and sends the first upper phase material to a second reactor; The second distillation tower performs distillation separation on the first lower phase material to obtain neutral oil and organic extractant respectively; Sulfuric acid and an organic extractant are added to the second reactor; then the sulfuric acid, the organic extractant and the first upper phase material react in the second reactor at 30-40° C. for 0.1-1 h to obtain a second mixed liquid; then the second reactor transports the second mixed liquid to a second separation unit; The second separation unit separates the second mixed liquid to obtain cyclohexane acid; The second separation unit comprises: a second phase separation tank, a first filter, a second filter, an extraction tower, a first distillation tower, and a third distillation tower; the second separation unit separates and processes the second mixed liquid to obtain cyclohexane acid; and comprises: The second reactor transports the second mixed liquid to the second phase separation tank; then the second phase separation tank performs phase separation on the second mixed liquid to obtain a second upper phase material and a second lower phase material; then the second phase separation tank transports the second upper phase material to the first filter, and transports the second lower phase material to the second filter; The first filter filters the second upper phase material to obtain impurities and a first filtrate, respectively; and then the first filter transports the first filtrate to an extraction tower; The extraction tower uses an organic extractant to reversely extract the first filtrate to obtain a third upper phase material and a third lower phase material; then the extraction tower transports the third upper phase material to a third distillation tower, and transports the third lower phase material to a second filter; The third distillation tower performs distillation separation on the third upper phase material to obtain an organic extractant and sodium sulfate wastewater respectively; The second filter filters the second lower phase material and the third lower phase material to obtain impurities and a second filtrate; then the second filter transports the second filtrate to the first distillation tower; The first distillation tower performs distillation separation on the second filtrate to obtain cyclohexane acid.

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