Anti-fouling composition for treating tar-containing high-salinity wastewater and application thereof

Abstract

The present application provides a scale inhibition composition for treating tar-containing high-salinity wastewater and application thereof. The scale inhibition composition provided by the present application comprises the following components in percentage by weight: 10-60% of an organic solvent; 20-70% of a crystallization inducer; 14-23% of a scale inhibition dispersant; and 0.1-1% of a nucleating agent. The scale inhibition composition can be used to prevent tar in wastewater from plugging wastewater treatment equipment.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment and relates to an anti-scaling composition for treating tar-containing high-salt wastewater and its application. Background Technology

[0002] Coal tar (generally referring to coal tar) is rich in highly aromatic organic compounds based on carbon. Its earliest source is a byproduct obtained during the dry distillation of coal to produce coke and coal gas under high temperatures or redox conditions. It possesses properties such as thermoplasticity, reluctance to degrade, and irritation. As the temperature decreases, the viscosity of coal tar increases, gradually becoming viscous and even hardening upon cooling, easily causing blockages in pipelines and equipment. During chemical production processes, it is continuously enriched as products are produced or separated and purified, significantly impacting pipelines and equipment. It is a substance that restricts continuous and stable production, a contributing factor to safety accidents, and a significant occupational health hazard. Therefore, the treatment of coal tar-containing wastewater has become both a necessity and an external requirement for the sustainable and healthy development of the chemical, pharmaceutical, agrochemical, coal chemical, and related industries.

[0003] High-salinity wastewater refers to wastewater with a total salt content of at least 0.5% wt, primarily originating from chemical plants and the extraction and processing of oil and natural gas. This type of wastewater contains various substances (including salt, oil, organic heavy metals, and radioactive materials), and its generation pathways are widespread, with emissions increasing year by year. Currently, biological methods are mainly used for treatment, but high concentrations of salt inhibit microorganisms, making treatment difficult, especially for high-salinity wastewater containing tar. Therefore, how to treat this type of wastewater has become a significant issue affecting the sustainable development of related industries.

[0004] Currently, some companies choose to add oxidants to remove tar. However, due to the presence of numerous inorganic salts in the wastewater and the difficulty in oxidizing tar due to its molecular structure and viscosity, and given past negative cases in the industry where the addition of inorganic sodium chlorate has induced explosions in waste treatment facilities, this method not only fails to achieve ideal results but also carries certain safety risks. Existing research on tar-clogging pipelines mainly focuses on optimizing engineering equipment and introducing tar cleaning agents.

[0005] Reference 1 suggests that adding a fluid unblocking device can alleviate the problems of tar residue deposition at the bottom of the equipment and pipe blockage. This involves a series of hardware modifications and is costly.

[0006] Reference 2 discloses a tar cleaning agent with good tar removal function, but the melting point of the alkyl polyoxyethylene ether in its components is about 70°C. This component has a large amount of leakage under conditions above 70°C, so the machine needs to be stopped before cleaning.

[0007] Reference 3 uses a cleaning agent to solve the clogging problem caused by heavy and thick organic scale formed by aromatic organic solvents in wastewater. However, this formula is only for fluorene wastewater without calcium and magnesium ions and does not take into account wastewater containing calcium and magnesium ions, thus limiting its applicability.

[0008] References:

[0009] Reference 1: CN203307286U

[0010] Reference 2: CN104498206A

[0011] Reference 3: CN113150880A Summary of the Invention

[0012] The problem the invention aims to solve

[0013] The traditional method for treating high-salinity wastewater is thermal separation, which mainly uses evaporators for evaporation. However, during the evaporation process, tar in the high-salinity wastewater tends to adhere to the pipes, causing scale buildup on the equipment, eventually clogging the pipes and corroding the equipment, which is detrimental to the continuity and stability of the treatment.

[0014] In view of the above problems, it is very important to provide an online treatment method for effectively preventing tar from clogging equipment pipelines in high-salt wastewater and the anti-scaling composition used therein.

[0015] Solution for solving the problem

[0016] Preliminary experiments revealed that in treating high-salt wastewater containing tar, smaller salt crystals are more prone to forming clusters and being encapsulated by tar and other materials. Due to its adhesive properties, tar easily adheres to pipes, eventually forming hard lumps that can clog pipes or impair the operation of pumps and centrifuges. Conversely, larger salt crystals and smaller surface areas per unit mass reduce the likelihood of tar encapsulation; instead, the tar is encapsulated within the salt crystals. In this case, the fluid formed by the salt crystals and water has a certain scouring effect on evaporators and pipes, resulting in better flowability and effectively preventing tar blockage.

[0017] Based on this, the present invention effectively solves the problem of equipment blockage during the evaporation process of high-salt wastewater containing tar without hardware modification.

[0018] [1] The present invention provides a scale inhibitor composition for treating tar-containing high-salt wastewater, comprising the following components by weight percentage: 10% to 60% organic solvent; 20% to 70% crystallization inducer; 14% to 23% scale inhibitor and dispersant; and 0.1% to 1% nucleating agent;

[0019] Preferably, the organic solvent is at least one of ethylene glycol monoethers and pyridine and its derivatives; and / or,

[0020] The crystallization inducing agent is at least one of a polymer containing hydroxyl, amide, and / or ester groups; and / or

[0021] The scale inhibitor / dispersant is at least one of organic acids; and / or

[0022] The nucleating agent is at least one of an inorganic salt and silicon dioxide.

[0023] [2] The anti-scaling composition according to [1], wherein,

[0024] The organic solvent is at least one selected from ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, pyridine, methylpyridine, dimethylpyridine, and trimethylpyridine; and / or

[0025] The crystallization inducing agent is at least one selected from polyethylene glycol and its derivatives, polyvinyl alcohol and its derivatives, poly(meth)acrylic acid and its derivatives, and polysorbates; preferably, the polyethylene glycol and its derivatives are at least one selected from polyethylene glycol, polyethylene glycol monostearate, and polyethylene glycol monomethyl ester; and / or, preferably, the polyvinyl alcohol and its derivatives are at least one selected from polyvinyl alcohol and polyacryl alcohol; and / or, preferably, the poly(meth)acrylic acid and its derivatives are at least one selected from poly(2-hydroxyethyl methacrylate) and polyacrylamide; and / or

[0026] The scale inhibitor / dispersant is at least one selected from benzoic acid, acetic acid, citric acid, and oxalic acid; and / or

[0027] The nucleating agent is at least one of sodium chloride and silicon dioxide; preferably, the particle size of the nucleating agent is 400-3200 μm.

[0028] [3] The anti-scaling composition according to [1] or [2], wherein,

[0029] The organic solvent is ethylene glycol monobutyl ether;

[0030] The crystallization inducer is polyethylene glycol;

[0031] The scale inhibitor and dispersant is benzoic acid;

[0032] The nucleating agent is sodium chloride.

[0033] [4] The anti-scaling composition according to any one of [1] to [3], wherein the salinity of the tar-containing high-salt wastewater is 6.7%-18.0% and the tar content of the tar-containing high-salt wastewater is 0.2%-0.6%;

[0034] Preferably, the hardness of the tar-containing high-salt wastewater is 600-800 mg / L;

[0035] More preferably, the COD of the tar-containing high-salt wastewater is 12,000-30,000 mg / L.

[0036] [5] The present invention also provides the use of the anti-scaling composition according to any one of [1] to [4] for treating tar-containing high-salt wastewater.

[0037] [6] Furthermore, the present invention provides a method for treating tar-containing high-salt wastewater, which includes the following steps:

[0038] The anti-scaling composition described in any one of [1] to [4] is mixed with tar-containing high-salt wastewater, evaporated, and subjected to three-phase separation to obtain a solid phase, a liquid phase, and a gas phase; preferably, the gas phase obtained after the three-phase separation is condensed to obtain condensate; and / or

[0039] Preferably, the liquid phase obtained after the three-phase separation is reused in the next round of wastewater treatment; and / or

[0040] Preferably, the solid phase obtained after the three-phase separation is collected to obtain solid waste or by-product inorganic salts.

[0041] [7] According to the method described in [6], the amount of the anti-scaling composition is 0.4% to 1% based on the total capacity of the evaporator.

[0042] [8] The method according to [6] or [7], wherein the evaporation temperature is 20 to 120°C.

[0043] [9] The method according to any one of [6] to [8], wherein the salinity of the tar-containing high-salt wastewater is 6.7%-18.0% and the tar content of the tar-containing high-salt wastewater is 0.2%-0.6%;

[0044] Preferably, the hardness of the tar-containing high-salt wastewater is 600-800 mg / L;

[0045] More preferably, the COD of the tar-containing high-salt wastewater is 12,000-30,000 mg / L.

[0046]

[10] The method according to any one of [6] to [9], wherein,

[0047] The gas phase enters the cooling tower for condensation; and / or

[0048] The liquid phase is circulated to the inlet of the heating chamber for the next round of wastewater treatment; and / or

[0049] The solid phase is collected using a thickener and a centrifuge.

[0050] The effects of the invention

[0051] 1. This invention does not require hardware modification, saving investment and space. The anti-scaling composition of this invention can be circulated online, making it highly operable.

[0052] 2. The anti-scaling composition of the present invention can form crystals with large particle size and good fluidity, which can effectively prevent the blockage of equipment and pipelines;

[0053] 3. The anti-scaling composition provided by this invention effectively reduces metal corrosion and better protects the equipment;

[0054] 4. The anti-scaling composition of the present invention is simple to use, can be operated online, which helps to improve the continuity and stability of the evaporator and greatly reduces the labor intensity of operators. Attached Figure Description

[0055] Figure 1 : Schematic diagram of online use of the anti-scaling composition. Detailed Implementation

[0056] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0057] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0058] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0059] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0060] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0061] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0062] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be between 10-40℃.

[0063] In this specification, the term "crystallization inducer" refers to an agent that can promote the formation of crystals from crystallizable / depositable substances under certain conditions. Typical crystallization inducers include (but are not limited to) polymers containing hydroxyl, amide, and / or ester groups.

[0064] In this specification, the term "scale inhibitor / dispersant" refers to an agent that, under certain conditions, can promote the dispersion of crystallizable / depositable substances in a system, thereby preventing or delaying their formation of scale in cavities or pipes. Typical scale inhibitors / dispersants include (but are not limited to) organic acids.

[0065] In this specification, the term "nucleating agent" refers to a reagent that can provide crystal growth centers or deposit nuclei for crystallizable / depositable materials under certain conditions. Typical nucleating agents include (but are not limited to) powdered inorganic salts, powdered silica, etc., and the particle size of the nucleating agent can be adjusted according to actual needs.

[0066] <First Aspect>

[0067] A first aspect of the present invention relates to an anti-scaling composition for treating tar-containing high-salt wastewater, comprising the following components: an organic solvent, a crystallization inducer, a scale inhibitor dispersant, and a nucleating agent.

[0068] In some specific embodiments of the present invention, the salinity of the tar-containing high-salt wastewater is 6.7%-18.0%; the tar content is 0.2%-0.6%; the hardness is 600-800 mg / L; and the COD is 12000-30000 mg / L.

[0069] In some specific embodiments of the present invention, the organic solvent is at least one of ethylene glycol monoethers and pyridine and its derivatives. Specifically, ethylene glycol monoethers may be selected from ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether (such as ethylene glycol mono-n-propyl ether, ethylene glycol monoisopropyl ether), ethylene glycol monobutyl ether (such as ethylene glycol mono-n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono-sec-butyl ether, ethylene glycol mono-tert-butyl ether), etc.; pyridine and its derivatives may be selected from pyridine, methylpyridine (such as 2-methylpyridine, 3-methylpyridine, 4-methylpyridine), dimethylpyridine, etc. (e.g., 2,3-dimethylpyridine, 2,4-dimethylpyridine, 2,5-dimethylpyridine, 2,6-dimethylpyridine, 3,4-dimethylpyridine, 3,5-dimethylpyridine) and trimethylpyridine (e.g., 2,3,4-trimethylpyridine, 2,3,5-trimethylpyridine, 2,3,6-trimethylpyridine, 2,4,5-trimethylpyridine, 2,4,6-trimethylpyridine, 3,4,5-trimethylpyridine), etc.

[0070] In some specific embodiments of the present invention, the percentage of organic solvent in the anti-scaling composition is 10% to 60%, for example, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, etc., preferably 25% to 30%. When the proportion of organic solvent is within the above range, the solubility of tar can be effectively increased.

[0071] In some specific embodiments of the present invention, the crystallization inducer is at least one polymer containing hydroxyl, amide, and / or ester groups. Preferably, it may be selected from at least one of polyethylene glycol and its derivatives, polyvinyl alcohol and its derivatives, poly(meth)acrylic acid and its derivatives, and polysorbates. Specifically, polyethylene glycol and its derivatives may be selected from polyethylene glycol, polyethylene glycol monostearate, polyethylene glycol monomethyl ester, etc.; polyvinyl alcohol and its derivatives may be selected from polyvinyl alcohol and polyacryl alcohol, etc.; poly(meth)acrylic acid and its derivatives may be selected from poly(2-hydroxyethyl methacrylate) and polyacrylamide, etc.

[0072] In some specific embodiments of the present invention, the crystallization inducer accounts for 20% to 70% of the scale-inhibiting composition, for example, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, etc., preferably 40% to 60%, more preferably 50% to 55%.

[0073] In some specific embodiments of the present invention, the scale inhibitor / dispersant is at least one of organic acids. Specifically, the organic acid may be selected from benzoic acid, acetic acid, citric acid, and oxalic acid, etc.

[0074] In some specific embodiments of the present invention, the scale inhibitor / dispersant accounts for 14% to 23% of the scale-inhibiting composition, for example, 14%, 16%, 17%, 18%, 19%, 20%, 21%, 23%, etc., preferably 17% to 21%, more preferably 18% to 20%. The scale inhibitor / dispersant can induce inorganic scale, residual tar, etc. located on the pipe wall to enter the mixed liquid, thereby effectively protecting the equipment. When the content of the scale inhibitor / dispersant is within the above range, the best protective effect can be achieved.

[0075] In some specific embodiments of the present invention, the nucleating agent is at least one of sodium chloride and silicon dioxide.

[0076] In some specific embodiments of the present invention, the particle size of the nucleating agent is 400-3200μm, for example, it can be 400μm, 800μm, 1200μm, 1600μm, 2000μm, 2400μm, 2800μm, 3200μm, etc.

[0077] In some specific embodiments of the present invention, the nucleating agent accounts for 0.1% to 1% of the scale-inhibiting composition, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc. The nucleating agent can induce inorganic salts in wastewater to form large-diameter crystal particles. Combined with the above-mentioned crystallization inducing agent, it induces inorganic salts to form even larger-diameter crystal particles, adsorbing impurities such as tar into the crystals, thereby achieving the purpose of preventing tar from clogging the pipes.

[0078] <Second aspect>

[0079] The second aspect of the invention relates to the use of the anti-scaling composition described in the first aspect for treating tar-containing, high-salt wastewater.

[0080] <Third aspect>

[0081] A third aspect of the present invention relates to a method for treating tar-containing, high-salt wastewater, comprising the following steps:

[0082] The anti-scaling composition described in the first aspect is mixed with tar-containing high-salt wastewater, evaporated, and subjected to three-phase separation to obtain a solid phase, a liquid phase, and a gas phase.

[0083] In some specific embodiments of the present invention, the gas phase obtained from the three-phase separation is condensed to obtain condensate. Specifically, the condensation is carried out in a cooling tower. The liquid phase obtained from the three-phase separation can be reused in the next round of wastewater treatment. Specifically, the liquid phase is circulated to the inlet of the heating chamber by a circulating pump for the next round of wastewater treatment. The solid phase obtained after the three-phase separation is collected to obtain solid waste and / or inorganic salt by-products. Specifically, the solid phase is collected by a thickener and a centrifuge, and the obtained inorganic salt by-products can be further recycled.

[0084] In some specific embodiments of the present invention, the salinity of the tar-containing high-salt wastewater is 6.7%-18.0%; the tar content is 0.2%-0.6%; the hardness is 600-800 mg / L; and the COD is 12000-30000 mg / L.

[0085] In some specific embodiments of the present invention, the amount of the anti-scaling composition is 0.4% to 1% based on the total capacity of the evaporator, for example, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc. Specifically, the evaporator is a wastewater continuous treatment evaporator, and the wastewater treatment volume is much larger than the evaporator volume, so the wastewater is kept in a state of filling the evaporator.

[0086] In some specific embodiments of the present invention, the evaporation temperature is 20 to 120°C, for example, it can be 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, etc.

[0087] In some specific embodiments of the present invention, the anti-scaling composition can be used in a continuous injection cycle with wastewater, which maximizes the utilization of the anti-scaling composition and can be carried out without stopping the equipment, thereby improving the continuity and stability of equipment operation.

[0088] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0089] The raw water used for evaporation in the following examples all comes from wastewater from an agrochemical company. The table below shows the water quality indicators of this raw water.

[0090] Table 1

[0091]

[0092] The evaporator in the following embodiments has a capacity of 40m³.3 The amount of anti-scaling composition added is 0.5% based on the evaporator capacity.

[0093] Example 1

[0094] An anti-scaling composition suitable for treating tar-containing, high-salt wastewater, the anti-scaling composition being a suspension prepared according to the raw material formulation of Example 1 in Table 2.

[0095] How to use:

[0096] The prepared anti-scaling composition is connected to the inlet of the heating chamber and thoroughly mixed with the raw water to be evaporated. Evaporation proceeds normally, with the temperature controlled at 110℃. The gaseous phase is converted into condensate through heat exchange; the solid phase is fed into a centrifuge through a thickener, ultimately forming salt sludge; the liquid phase is returned to the inlet of the heating chamber via a circulating pump. After continuous and stable operation, the condensate and salt sludge are tested.

[0097] Example 2

[0098] An anti-scaling composition suitable for treating tar-containing, high-salt wastewater, the anti-scaling composition being a suspension prepared according to the raw material formulation of Example 2 in Table 2.

[0099] How to use:

[0100] The prepared anti-scaling composition is connected to the inlet of the heating chamber and thoroughly mixed with the raw water to be evaporated. Evaporation proceeds normally, with the temperature controlled at 110℃. The gaseous phase is converted into condensate through heat exchange; the solid phase is fed into a centrifuge through a thickener, ultimately forming salt sludge; the liquid phase is returned to the inlet of the heating chamber via a circulating pump. After continuous and stable operation, the condensate and salt sludge are tested.

[0101] Example 3

[0102] An anti-scaling composition suitable for treating tar-containing, high-salt wastewater, wherein the anti-scaling composition is a suspension prepared according to the raw material formulation of Example 3 in Table 2.

[0103] How to use:

[0104] The prepared anti-scaling composition is connected to the inlet of the heating chamber and thoroughly mixed with the raw water to be evaporated. Evaporation proceeds normally, with the temperature controlled at 110℃. The gaseous phase is converted into condensate through heat exchange; the solid phase is fed into a centrifuge through a thickener, ultimately forming salt sludge; the liquid phase is returned to the inlet of the heating chamber via a circulating pump. After continuous and stable operation, the condensate and salt sludge are tested.

[0105] Example 4

[0106] An anti-scaling composition suitable for treating tar-containing, high-salt wastewater, the anti-scaling composition being a suspension prepared according to the raw material formulation of Example 4 in Table 2.

[0107] How to use:

[0108] The prepared anti-scaling composition is connected to the inlet of the heating chamber and thoroughly mixed with the raw water to be evaporated. Evaporation proceeds normally, with the temperature controlled at 110℃. The gaseous phase is converted into condensate through heat exchange; the solid phase is fed into a centrifuge through a thickener, ultimately forming salt sludge; the liquid phase is returned to the inlet of the heating chamber via a circulating pump. After continuous and stable operation, the condensate and salt sludge are tested.

[0109] Example 5

[0110] An anti-scaling composition suitable for treating tar-containing, high-salt wastewater, the anti-scaling composition being a suspension prepared according to the raw material formulation of Example 5 in Table 2.

[0111] How to use:

[0112] The prepared anti-scaling composition is connected to the inlet of the heating chamber and thoroughly mixed with the raw water to be evaporated. Evaporation proceeds normally, with the temperature controlled at 110℃. The gaseous phase is converted into condensate through heat exchange; the solid phase is fed into a centrifuge through a thickener, ultimately forming salt sludge; the liquid phase is returned to the inlet of the heating chamber via a circulating pump. After continuous and stable operation, the condensate and salt sludge are tested.

[0113] Example 6

[0114] An anti-scaling composition suitable for treating tar-containing, high-salt wastewater, the anti-scaling composition being a suspension prepared according to the raw material formulation of Example 6 in Table 2.

[0115] How to use:

[0116] The prepared anti-scaling composition is connected to the inlet of the heating chamber and thoroughly mixed with the raw water to be evaporated. Evaporation proceeds normally, with the temperature controlled at 110℃. The gaseous phase is converted into condensate through heat exchange; the solid phase is fed into a centrifuge through a thickener, ultimately forming salt sludge; the liquid phase is returned to the inlet of the heating chamber via a circulating pump. After continuous and stable operation, the condensate and salt sludge are tested.

[0117] Example 7

[0118] An anti-scaling composition suitable for treating tar-containing, high-salt wastewater, the anti-scaling composition being a suspension prepared according to the raw material formulation of Example 7 in Table 2.

[0119] How to use:

[0120] The prepared anti-scaling composition is connected to the inlet of the heating chamber and thoroughly mixed with the raw water to be evaporated. Evaporation proceeds normally, with the temperature controlled at 110℃. The gaseous phase is converted into condensate through heat exchange; the solid phase is fed into a centrifuge through a thickener, ultimately forming salt sludge; the liquid phase is returned to the inlet of the heating chamber via a circulating pump. After continuous and stable operation, the condensate and salt sludge are tested.

[0121] Table 2

[0122]

[0123] Condensate water index test

[0124] 1. Chemical Oxygen Demand (COD) Test

[0125] Chemical oxygen demand (COD) was determined according to HJ 828-2017, "Determination of Chemical Oxygen Demand in Water - Dichromate Method".

[0126] Plotting the calibration curve: Turn on the heater and preheat to the set temperature of 165℃±2℃. Select the pre-mixed reagent, shake the reagent well, and then unscrew the digestion tube cap. Measure the appropriate volume of COD standard series solution (sample) and slowly add it to the tube along the inner wall. Tighten the digestion tube cap, hold the cap and invert the tube to mix the solution, then wipe the outer wall of the tube clean with lint-free paper. Place the digestion tube into the heating hole of the heater at 165℃±2℃. The heater temperature will decrease slightly. When the temperature rises to 165℃±2℃, start heating for 15 minutes. Remove the digestion tube from the heater. When the digestion tube cools to about 60℃, hold the cap and invert the tube several times to homogenize the solution. Wipe the outer wall of the tube clean with lint-free paper, and let it stand to cool to room temperature. Measure the absorbance at a wavelength of 600nm±20nm using water as a reference solution with a photometer. Subtract the absorbance value from the blank test and plot the calibration curve.

[0127] Sample testing: Mercuric sulfate was used as a chloride ion shielding agent. The sample was diluted to a certain concentration (chloride ion concentration not greater than 1000 mg / L). The absorbance value of the sample was tested according to the standard test method, and the corresponding COD value was calculated according to the standard curve.

[0128] 2. Salinity test

[0129] The salinity of condensate was determined by conductivity method. A Shanghai Leici DDSJ-308A conductivity meter was used as the testing instrument. The "Salinity" mode was selected, the salinity constant was set, the electrode was calibrated in a standard salinity solution, and then the electrode was placed in the sample to be tested. The corresponding salinity reading was then recorded.

[0130] 3. Viscosity test

[0131] The dynamic viscosity of condensate was measured using an LVDV-2T viscometer. First, roughly estimate the viscosity range of the liquid being measured, then select the appropriate rotor and speed according to the range table. After selecting the range, coefficient, rotor, and speed, screw the selected rotor into the connecting screw. Rotate the lifting knob to slowly lower the instrument, gradually immersing the rotor into the liquid being measured until the rotor's liquid level mark is level with the liquid surface. Adjust the instrument to be level. Take the reading after stabilization.

[0132] 4. Hardness test

[0133] Hardness was determined according to GB / T 7477-1987 "Determination of Total Calcium and Magnesium in Water by EDTA Titration".

[0134] Take 50 mL of water sample and pour it into a 250 mL Erlenmeyer flask. Add 4 mL of ammonium chloride buffer solution, and then add 2–3 drops of Eriochrome Black T indicator. (Note: For water samples with high carbonate hardness, dilute the sample before adding the buffer solution or add 80%–90% of the EDTA standard solution volume (included in the titration volume). Otherwise, calcium carbonate will precipitate after adding the buffer solution, prolonging the endpoint.) Then titrate with the EDTA standard solution. The color changes from wine red to blue. The endpoint is reached when the last bit of purple disappears and sky blue just appears. The entire titration process should be completed within 5 minutes. Record the volume of disodium EDTA solution consumed. Calculate the concentration.

[0135] Salt mud index test

[0136] The salt produced in Examples 1-7 was weighed in a specified amount and placed in an oven at 65℃±2℃ until constant weight, which was used as the sample for the following determinations.

[0137] 1. Particle size mass fraction

[0138] According to the requirements of "General Test Method for Particle Size Determination in Salt Industry" (GB / T13025.1-2012): Weigh 100g of sample, accurate to 0.2g, and sieve using a test sieve with specified mesh size. After manual sieving for 2 minutes or sieve using a vibrating sieve machine for 1 minute, weigh the mass of the material remaining on the sieve, with an accuracy of 0.2g. The particle size results of the example are shown in Table 3.

[0139] 2. Mass fraction of residue on ignition

[0140] According to the requirements of the "General Method for Determination of Residue on Ignition of Chemical Reagents" (GB / T 9741-2008): Take a specified amount of sample and place it in a specified crucible or dish that has been constant-weighted at 650℃±50℃. Heat slowly until the organic matter is completely volatilized or carbonized. Cool and moisten the residue with 0.5 mL of sulfuric acid. Continue heating until the sulfuric acid vapor has escaped, and ignite in a high-temperature furnace at 650℃±50℃ to constant weight. The results of the ignition residue in the examples are shown in Table 3.

[0141] When tar is tested for ignition, it is burned into inorganic substances (CO2, H2O, etc.) and escapes from the system. Therefore, the loss on ignition of salt mud can represent the tar content.

[0142] Loss on ignition is calculated using the following formula:

[0143] P = (m2 - m1) / m × 100%

[0144] Where: P—loss on ignition, %;

[0145] m2 — Mass of residue and empty crucible, in grams;

[0146] m1—mass of the empty crucible, in grams;

[0147] m — the mass of the sample.

[0148] Table 3

[0149]

[0150] The anti-scaling composition and treatment method of the present invention can ensure that the mass fraction of crystals with a particle size of 400 μm or larger produced by evaporation of tar-containing high-salt wastewater is above 80.0%, the tar organic matter (loss on ignition) carried away by the salt crystals produced by crystallization is above 8.0%, and the chemical oxygen demand of the condensate after evaporation is below 13000 mg / L. In the above embodiments, the ratio screening of the two solvents, combined with other components, enhances the removal system of tar organic matter while increasing the crystal particle size.

[0151] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0152] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A scale inhibitor composition for treating tar-containing, high-salt wastewater, comprising the following components by weight percentage: 10%–60% organic solvent; 20%–70% crystallization inducer; 14%–19.5% scale inhibitor / dispersant; and 0.1%–1% nucleating agent; The organic solvent is at least one of ethylene glycol monoethers and pyridine and its derivatives; The crystallization inducer is at least one of polymers containing hydroxyl, amide and / or ester groups; The scale inhibitor / dispersant is at least one of benzoic acid, acetic acid, citric acid, and oxalic acid; The nucleating agent is at least one of sodium chloride and silicon dioxide; the particle size of the nucleating agent is 400-3200 μm; The salinity of the tar-containing high-salt wastewater is 6.7%-18.0%, and the tar content of the tar-containing high-salt wastewater is 0.2%-0.6%.

2. The anti-scaling composition according to claim 1, characterized in that, The organic solvent is at least one selected from ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, pyridine, methylpyridine, dimethylpyridine, and trimethylpyridine; and / or The crystallization inducer is at least one of polyethylene glycol and its derivatives, polyvinyl alcohol and its derivatives, poly(meth)acrylic acid and its derivatives, and polysorbate.

3. The anti-scaling composition according to claim 2, characterized in that, The polyethylene glycol and its derivatives are at least one of polyethylene glycol, polyethylene glycol monostearate, and polyethylene glycol monomethyl ester.

4. The anti-scaling composition according to claim 2, characterized in that, The polyvinyl alcohol and its derivatives are at least one of polyvinyl alcohol and polyacryl alcohol.

5. The anti-scaling composition according to claim 2, characterized in that, The poly(meth)acrylic acid and its derivatives are at least one of poly(2-hydroxyethyl methacrylate) and polyacrylamide.

6. The anti-scaling composition according to any one of claims 1-5, characterized in that, The organic solvent is ethylene glycol monobutyl ether; The crystallization inducer is polyethylene glycol; The scale inhibitor and dispersant is benzoic acid; The nucleating agent is sodium chloride.

7. The anti-scaling composition according to any one of claims 1-5, characterized in that, The hardness of the tar-containing, high-salt wastewater is 600-800 mg / L.

8. The anti-scaling composition according to claim 7, characterized in that, The COD of the tar-containing, high-salt wastewater is 12,000-30,000 mg / L.

9. Use of the anti-scaling composition according to any one of claims 1-8 for treating tar-containing, high-salt wastewater.

10. A method for treating tar-containing, high-salt wastewater, comprising the following steps: The anti-scaling composition according to any one of claims 1-8 is mixed with tar-containing high-salt wastewater, evaporated, and subjected to three-phase separation to obtain a solid phase, a liquid phase, and a gas phase. The dosage of the anti-scaling composition is 0.4% to 1% based on the total capacity of the evaporator; The evaporation temperature is 20~120℃.

11. The method according to claim 10, characterized in that, The gas phase obtained after the three-phase separation is condensed to obtain condensate.

12. The method according to claim 10, characterized in that, The liquid phase obtained after the three-phase separation is reused in the next round of wastewater treatment.

13. The method according to claim 10, characterized in that, The solid phase obtained after the separation of the three phases is collected to obtain solid waste and / or inorganic salt byproducts.

14. The method according to any one of claims 10-13, characterized in that, The salinity of the tar-containing high-salt wastewater is 6.7%-18.0%, and the tar content of the tar-containing high-salt wastewater is 0.2%-0.6%.

15. The method according to claim 14, characterized in that, The hardness of the tar-containing, high-salt wastewater is 600-800 mg / L.

16. The method according to claim 15, characterized in that, The COD of the tar-containing, high-salt wastewater is 12,000-30,000 mg / L.

17. The method according to any one of claims 10-13, characterized in that, The gas phase enters the cooling tower for condensation; and / or The liquid phase is circulated to the inlet of the heating chamber for the next round of wastewater treatment; and / or The solid phase is collected using a thickener and a centrifuge.

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