A treatment method for wastewater from indene resin production

Abstract

The present invention discloses a method for treating waste water in indene resin production. In the process of preparing indene resin, the present invention adopts a two-step water washing method to remove the catalyst in the indene resin polymerization liquid. The two-step washing water is recycled respectively. When the content of fluoborate ions in the washing water is ≥ 30,000 ppm without affecting the product indexes of indene resin, potassium salt is used for precipitation treatment. After treatment, the washing water is continuously recycled to the catalyst removal process of the polymerization liquid, and the cycle repeats. By adopting the treatment method of the present invention, there is no external discharged waste water in the indene resin production process, and potassium fluoborate can be by-produced. The process is green and environment-friendly, and the economic benefit is increased.

Description

Technical Field

[0001] The present invention belongs to the field of wastewater treatment, and particularly relates to a method for treating wastewater from indene resin production. Background Art

[0002] Indene is an aromatic hydrocarbon with the molecular formula C 6 H 4 C 3 H 4 , which is a colorless transparent oily liquid at room temperature. It is extracted from coal tar, has a boiling point of 182.4 °C, and can be used to produce indene resin. Coumarone (i.e., 2,3-benzofuran) is an aromatic heterocyclic organic compound with the chemical formula C 8 H 6 O and is a colorless oily liquid at room temperature.

[0003] Indene resin in a broad sense includes indene resin in a narrow sense (polymerized only from monomer indene) and indene-coumarone resin (also called coumarone-indene resin or coumarone resin, which is polymerized from indene and coumarone). Unless otherwise specified, indene resin in this article refers to indene resin in a broad sense. Indene resin has excellent properties such as acid resistance, alkali resistance, adhesiveness, plasticization, and reinforcement, and is mainly applied in related fields such as coatings, adhesives, rubber, and inks.

[0004] In the production process of indene resin, boron trifluoride ether complex (BF 3 ·Et 2 O) is used as a catalyst. After the reaction, the catalyst is removed by the water washing method. The most serious defect of this method is the generation of a large amount of wastewater containing aromatic hydrocarbons and boron trifluoride. The aromatic hydrocarbons in the wastewater exist in a dissolved state and an emulsified state, and boron trifluoride is a highly toxic chemical, mainly existing in the form of F - and BF 4 - in the wastewater. Since BF 4 - will slowly hydrolyze and release a large amount of F - , it increases the difficulty of wastewater treatment. F - has a strong electronegativity and is extremely easy to combine with other elements, and has great toxic effects on humans and organisms.

[0005] In the wastewater from indene resin production, fluorine exists in the form of fluoborate ions (BF 4 - ), fluoride ions (F - ), etc. The content of fluoborate ions is about 12000 mg / L, and the fluoride ions are about 3000 mg / L. Fluoboric acid is a very stable compound in which fluorine is coordinated to boron. The wastewater containing fluoborate ions will slowly hydrolyze in water, and a large amount of F -, resulting in serious fluorine pollution. Commonly used methods for treating wastewater containing fluoro-borate ions at home and abroad include: chemical hydrolysis method, potassium salt precipitation method, ion exchange method, adsorption method, foam separation method, etc. A relatively practical and effective method for treating wastewater containing fluoro-borate ions is the hydrolysis precipitation method, that is, BF 4 - decomposes to release F - , and then the method for treating free F - is used for removal.

[0006] For industrial production wastewater containing fluorine, it is mainly treated by the lime milk precipitation method. The main function of the lime milk precipitation method is to remove fluoride ions, and the removal effect on fluoro-borate ions is relatively small.

[0007] With the increasing awareness of environmental protection among people, the pollution caused by boron-containing and fluorine-containing organic wastewater to the environment has received more and more attention.

[0008] CN112744942A discloses a pretreatment method for wastewater containing fluorine and boron. This method uses two-step calcium precipitation to remove most of the fluoride ions in the wastewater, and then potassium salt compounds such as potassium hydroxide are added to the obtained wastewater containing fluoro-borate ions to remove most of the fluoro-borate ions in the wastewater. This method can remove most of the fluoride ions and fluoro-borate ions in the wastewater containing fluorine and boron, but it cannot treat them to below the national discharge standard.

[0009] CN216890526U discloses a resin production wastewater treatment system. This wastewater treatment system includes a pretreatment system, a biochemical treatment system, and a deep treatment system connected in sequence; the pretreatment system includes an oil separation device, a flotation device, a micro-electrolysis tower, a first Fenton reaction device, and a first sedimentation tank connected in sequence; the biochemical treatment system includes a hydrolysis acidification tank, an IC reaction tower, an activated sludge tank, a contact oxidation tank, and a second sedimentation tank connected in sequence; the deep treatment system includes a second Fenton reaction device and a third sedimentation tank connected in sequence. This resin production wastewater treatment system has a large equipment investment, a cumbersome process, and a high cost.

[0010] Therefore, it is necessary to provide a treatment method for indene resin production wastewater that can be green and environmentally friendly, have a low input cost, and meet national requirements. Summary of the Invention

[0011] To solve the problems existing in the prior art, the present invention provides a method for treating waste water from indene resin production. The waste water treatment process of indene resin in the present invention is a process of recycling and reusing. In the preparation process of indene resin, a two-step water washing method is adopted to remove the catalyst in the indene resin polymerization solution. The two washing waters are recycled respectively. When the content of fluoborate ions in the washing water is ≥ 30,000 ppm without affecting the product indexes of indene resin, potassium salt is used for precipitation treatment. After treatment, the washing water is continuously reused in the process of catalyst removal from the polymerization solution, and this process is repeated. By adopting the treatment method of the present invention, there is no external discharged waste water in the indene resin production process, and potassium fluoborate can be by-produced. The process is green and environmentally friendly and increases economic benefits.

[0012] Specifically, the present invention provides a method for treating waste water from indene resin production. The treatment method includes performing water washing on indene resin polymerization solution in multiple batches. The water washing of the indene resin polymerization solution in the first batch includes the following steps:

[0013] (1) First-step water washing: Add water to the indene resin polymerization solution in the first batch. The weight of the water is 45%-55% of the weight of the indene resin polymerization solution in the first batch. Stir at the first stirring temperature for the first stirring time, and then let it stand for liquid separation to obtain the polymerized solution after the first-step water washing in the first batch and the first-step washing water in the first batch;

[0014] (2) Second-step water washing: Add water to the polymerized solution after the first-step water washing in the first batch. The weight of the water is 45%-55% of the weight of the indene resin polymerization solution in the first batch. Stir at the second stirring temperature for the second stirring time, and then let it stand for liquid separation to obtain the polymerized solution after the second-step water washing in the first batch and the second-step washing water in the first batch;

[0015] The water washing of the indene resin polymer in the second and subsequent batches includes the following steps:

[0016] (1') First-step water washing: If the content of BF 4 - in the first-step washing water of the previous batch is < 30,000 mg / L, directly mix the indene resin polymerization solution in this batch and the first-step washing water of the previous batch, stir at the first stirring temperature for the first stirring time, and then let it stand for liquid separation to obtain the polymerized solution after the first-step water washing in this batch and the first-step washing water in this batch; if the content of BF 4 - in the first-step washing water of the previous batch is ≥ 30,000 mg / L, then according to the BF 4 - in the first-step washing water of the previous batch and K in the potassium salt +The molar ratio is 1:(0.5 - 0.9). Potassium salt is added to the first-step wash water of the previous batch, and stirred for the third stirring time at the third stirring temperature, then filtered to obtain the first-step wash water after treatment of the previous batch and the precipitate containing potassium fluoroborate. Then, the indene resin polymerization liquid of this batch and the first-step wash water after treatment of the previous batch are mixed, stirred for the first stirring time at the first stirring temperature, and left to stand for liquid separation to obtain the polymerization liquid after one-step water washing of this batch and the first-step wash water of this batch.

[0017] (2’)Second-step water washing: If the BF content in the second-step wash water of the previous batch is < 30000 mg / L, then directly mix the polymerization liquid after one-step water washing of this batch and the second-step wash water of the previous batch, stir for the second stirring time at the second stirring temperature, and leave to stand for liquid separation to obtain the polymerization liquid after two-step water washing of this batch and the second-step wash water of this batch; if the BF content in the second-step wash water of the previous batch is ≥ 30000 mg / L, then according to the molar ratio of BF and K in the potassium salt being 1:(0.5 - 0.9), add potassium salt to the second-step wash water of the previous batch, stir for the third stirring time at the third stirring temperature, filter to obtain the second-step wash water after treatment of the previous batch and the precipitate containing potassium fluoroborate, and then mix the polymerization liquid after one-step water washing of this batch and the second-step wash water after treatment of the previous batch, stir for the second stirring time at the second stirring temperature, and leave to stand for liquid separation to obtain the polymerization liquid after two-step water washing of this batch and the second-step wash water of this batch. 4 - content < 30000 mg / L, then directly mix the polymerization liquid after one-step water washing of this batch and the second-step wash water of the previous batch, stir for the second stirring time at the second stirring temperature, and leave to stand for liquid separation to obtain the polymerization liquid after two-step water washing of this batch and the second-step wash water of this batch; if the BF 4 - content ≥ 30000 mg / L, then according to the BF 4 - in the second-step wash water of the previous batch and K + in the potassium salt with a molar ratio of 1:(0.5 - 0.9), add potassium salt to the second-step wash water of the previous batch, stir for the third stirring time at the third stirring temperature, filter to obtain the second-step wash water after treatment of the previous batch and the precipitate containing potassium fluoroborate, and then mix the polymerization liquid after one-step water washing of this batch and the second-step wash water after treatment of the previous batch, stir for the second stirring time at the second stirring temperature, and leave to stand for liquid separation to obtain the polymerization liquid after two-step water washing of this batch and the second-step wash water of this batch.

[0018] In one or more embodiments, the potassium salt is selected from one or more of potassium chloride, potassium sulfate, potassium nitrate, and potassium alum.

[0019] In one or more embodiments, the potassium salt is potassium chloride.

[0020] In one or more embodiments, the first stirring temperature is 55 - 60 °C.

[0021] In one or more embodiments, the second stirring temperature is 55 - 60 °C.

[0022] In one or more embodiments, the third stirring temperature is 20 - 30 °C.

[0023] In one or more embodiments, the first stirring time is 25 - 35 min.

[0024] In one or more embodiments, the second stirring time is 25 - 35 min.

[0025] In one or more embodiments, the third stirring time is 25 - 35 min.

[0026] In one or more embodiments, the indene resin polymerization solution includes indene resin, solvent, hydrofluoric acid, and fluoboric acid.

[0027] In one or more embodiments, the pH value of the indene resin polymerization solution is 1 - 2.

[0028] In one or more embodiments, the solvent includes one or both selected from xylene and mesitylene.

[0029] In one or more embodiments, in the indene resin polymerization solution, the mass fraction of indene resin is 20% - 30%.

[0030] In one or more embodiments, the mass of the indene resin polymerization solution processed per batch is more than 500 g. Description of the Drawings

[0031] Figure 1 It is the process flow diagram of the water washing of the indene resin polymerization solution in Example 1.

[0032] Figure 2 It is the process flow diagram of the wastewater treatment of the indene resin polymerization solution in Examples 4 and 5. Detailed Description of the Invention

[0033] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art for the present invention. In case of conflicts, the definitions in this specification shall prevail.

[0034] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not in any way limit the scope of the present invention, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0035] As used herein, terms such as "comprising", "including", "containing", and similar terms encompass the meanings of "consisting essentially of" and "consisting of". For example, when the present disclosure states that "A comprises B and C", it should be considered that "A consists essentially of B and C" and "A consists of B and C" have been disclosed herein.

[0036] In this article, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be regarded as having covered and specifically disclosed all possible sub - ranges and individual numerical values (including integers and fractions) within the range.

[0037] In this text, unless otherwise specified, percentages refer to mass percentages and ratios refer to mass ratios.

[0038] In this text, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all alternatives, improvements, and equivalents of the methods and materials described in the present invention can be covered within the scope defined by the claims.

[0039] In this text, for the sake of concise description, not all possible combinations of all technical features in each embodiment or example are described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered to be within the scope described in this specification.

[0040] Existing treatment technologies for wastewater containing fluoride ions and fluoborate ions have the following disadvantages: (1) large equipment investment, numerous processes, and high costs; (2) it is very difficult to reduce F - to below 10 mg / L, failing to meet the national discharge standards. By adopting a treatment process of wastewater recycling + reuse, the present invention can recycle all the wastewater without discharging it externally without affecting the quality of the indene resin product, and can produce a by-product potassium fluoborate, which has high environmental and economic value.

[0041] In the present invention, indene resin includes unmodified indene resin and modified indene resin. Modified indene resin refers to the resin prepared by adding a modifier during the polymerization process of indene resin in order to improve the solubility of indene resin in water or lower alcohols, or to enhance the compatibility of indene resin with polar solvents. The modifier can be selected from hydroxyl-containing monomers (such as phenol, 4-hydroxystyrene, methyl 4-hydroxycinnamate, ethyl 4-hydroxycinnamate), carboxyl-containing monomers (such as methacrylate, acrylate), sulfur trioxide, etc.

[0042] In the present invention, indene resin polymerization liquid refers to the reaction liquid containing indene resin obtained by reacting the raw materials of indene resin in a solvent under the action of a catalyst. In the indene resin polymerization liquid, the mass fraction of indene resin can be 20% - 30%. The catalyst can be BF 3 ·Et 2 O. The solvent can be mesitylene, xylene, etc. The indene resin polymerization liquid contains corrosive substances such as hydrofluoric acid and fluoboric acid, and the pH is 1 - 2.

[0043] The present invention discovers that a two-step water washing method is adopted to remove the catalyst in the indene resin polymerization solution. The two washing waters are respectively recycled. Without affecting the indicators (pH value, ash content) of the indene resin product, when the content of fluoborate ions in the washing water reaches ≥30000 ppm, potassium salt is used for precipitation treatment. After treatment, the washing water is continuously recycled to the catalyst removal process of the polymerization solution, and this process is repeated cyclically.

[0044] The method for treating the wastewater from indene resin production in the present invention includes washing the indene resin polymerization solution in multiple batches. In some embodiments, the mass of the indene resin polymerization solution treated in each batch is ≥500 g.

[0045] In the present invention, the water washing of the indene resin polymerization solution in the first batch includes the following steps:

[0046] (1) The first-step water washing: Add water to the indene resin polymerization solution in the first batch. The weight of the water is 45%-55%, for example 50%, of the weight of the indene resin polymerization solution in the first batch. Stir at the first stirring temperature for the first stirring time, then let it stand for liquid separation to obtain the polymerized solution after the first-step water washing in the first batch and the first-step washing water in the first batch;

[0047] (2) The second-step water washing: Add water to the polymerized solution after the first-step water washing in the first batch. The weight of the water is 45%-55%, for example 50%, of the weight of the indene resin polymerization solution in the first batch. Stir at the second stirring temperature for the second stirring time, then let it stand for liquid separation to obtain the polymerized solution after the second-step water washing in the first batch and the second-step washing water in the first batch.

[0048] In the present invention, the first-step washing water is also called washing water 1, and the second-step washing water is also called washing water 2. In the first-step water washing of each batch, the first stirring temperature can be above 55°C, for example 55 - 60°C, and the first stirring time can be above 25 min, for example 25 - 35 min, 30 min. In the second-step water washing of each batch, the second stirring temperature can be above 55°C, for example 55 - 60°C, and the second stirring time can be above 25 min, for example 25 - 35 min, 30 min.

[0049] The water washing of the indene resin polymer in the second and subsequent batches includes the following steps:

[0050] (1') The first-step water washing: If the content of BF in the first-step washing water of the previous batch is <30000 mg / L, then directly mix the indene resin polymerization solution in this batch and the first-step washing water of the previous batch, stir at the first stirring temperature for the first stirring time, and let it stand for liquid separation to obtain the polymerized solution after the first-step water washing in this batch and the first-step washing water in this batch; If the content of BF in the first-step washing water of the previous batch is 4 - <30000 mg / L, then directly mix the indene resin polymerization solution in this batch and the first-step washing water of the previous batch, stir at the first stirring temperature for the first stirring time, and let it stand for liquid separation to obtain the polymerized solution after the first-step water washing in this batch and the first-step washing water in this batch; If the content of BF in the first-step washing water of the previous batch is 4 -If the content is ≥30000 mg / L, the BF in the first step of the previous batch of washing water should be used. 4 - and potassium salts + The molar ratio of the first washing water to the first washing water of the previous batch is 1: (0.5-0.9), potassium salt is added to the first washing water of the previous batch, stirred at the third stirring temperature for the third stirring time, filtered to obtain the first washing water after the previous batch of treatment and the precipitate of the potassium salt of fluorine-containing borate, and then the polymerized liquid of the indene resin of this batch and the first washing water after the previous batch of treatment are mixed, stirred at the first stirring temperature for the first stirring time, and allowed to stand for separation to obtain the polymerized liquid after the first washing of this batch and the first washing water of this batch;

[0051] (2') Second step water washing: If the BF in the second step washing water of the previous batch 4 - If the content is less than 30000 mg / L, directly mix the polymer solution after the first step water washing of this batch and the second step washing water of the previous batch, stir at the second stirring temperature for the second stirring time, stand and separate the liquids to obtain the polymer solution after the second step water washing of this batch and the second step washing water of this batch; if BF in the second step washing water of the previous batch 4 - If the content is ≥30000 mg / L, the BF in the second step of the previous batch of washing water 4 - and potassium salts + The molar ratio is 1:(0.5-0.9), potassium salt is added to the second-step washing water of the previous batch, stirred at the third stirring temperature for the third stirring time, filtered to obtain the second-step washing water after the previous batch of treatment and the precipitate of fluorine-containing potassium borate salt, and then the polymer solution after one-step water washing of this batch and the second-step washing water after the previous batch of treatment are mixed, stirred at the second stirring temperature for the second stirring time, and allowed to stand for separation to obtain the polymer solution after two-step water washing of this batch and the second-step washing water of this batch.

[0052] The potassium salt suitable for the present invention can be one or more selected from potassium chloride, potassium sulfate, potassium nitrate and potassium aluminum sulfate. In some embodiments, the potassium salt used in the present invention is potassium chloride. When potassium salt is added to the wash water, BF 4 - and potassium salts + The molar ratio of can be 1:(0.5-0.9), such as 1:0.6, 1:0.7, 1:0.8. After adding potassium salt to the washing water, the third stirring temperature can be 20-30°C, such as room temperature (25°C), and the third stirring time can be more than 25 minutes, such as 25-35 minutes, 30 minutes.

[0053] In some embodiments, the method for treating indene resin production wastewater of the present invention comprises performing multiple batches of indene resin polymerization liquid water washing, wherein the first batch of indene resin polymerization liquid water washing comprises the following steps:

[0054] (1) First step water washing: add half the weight of water to the first batch of indene resin polymerization liquid, stir at a constant temperature of 55-60°C for 30 minutes, stand and separate the liquids to obtain the first batch of one-step water-washed polymerization liquid and the first batch of washing water 1;

[0055] (2) Second step of water washing: add half the weight of water to the first batch of polymer solution after the first step of water washing, stir at a constant temperature of 55-60°C for 30 min, and allow to stand for separation to obtain the first batch of polymer solution after the second step of water washing and the first batch of washing water 2;

[0056] The second and subsequent batches of indene resin polymer water washings include the following steps:

[0057] (1') First step of water washing: If the previous batch of washing water 1 contains BF 4 - If the content is less than 30000 mg / L, directly mix the indene resin polymerization liquid of this batch with the washing water 1 of the previous batch, stir at a constant temperature of 55-60℃ for 30min, let it stand and separate the liquids to obtain the polymerization liquid after one-step washing of this batch and the washing water 1 of this batch; if the BF in the washing water 1 of the previous batch 4 - If the content is ≥30000 mg / L, the previous batch of washing water 1 is treated according to BF 4 - and K + The molar ratio of is 1:(0.5-0.9), potassium chloride is added, stirred at room temperature for 30 minutes, filtered, and the washing water 1 after the previous batch of treatment and the precipitate of fluorine-containing potassium borate are obtained, and then the indene resin polymerization liquid of this batch and the washing water 1 after the previous batch of treatment are mixed, stirred at a constant temperature of 55-60°C for 30 minutes, and allowed to stand for separation to obtain the one-step water-washed polymerization liquid of this batch and the washing water 1 of this batch;

[0058] (2') Second step water washing: If the previous batch of washing water 2 contains BF 4 - If the content is less than 30000 mg / L, directly mix the polymer solution after the first step water washing of this batch and the washing water 2 of the previous batch, stir at a constant temperature of 55-60℃ for 30min, let it stand and separate the liquids to obtain the polymer solution after the second step water washing of this batch and the washing water 2 of this batch; if the BF in the washing water 2 of the previous batch 4 - If the content is ≥30000 mg / L, the previous batch of washing water 2 is treated according to BF 4 - and K +Potassium chloride was added in a molar ratio of 1:(0.5 - 0.9), stirred at room temperature for 30 min, filtered to obtain the washing water 2 after the treatment of the previous batch and the precipitate containing potassium fluoroborate, and then the polymerized liquid after the first-step water washing of this batch and the washing water 2 after the treatment of the previous batch were mixed, stirred at a constant temperature of 55 - 60 °C for 30 min, allowed to stand for liquid separation to obtain the polymerized liquid after the second-step water washing of this batch and the washing water 2 of this batch.

[0059] The present invention has the following beneficial effects: By using the treatment method of the present invention, there is no external wastewater discharge during the production process of indene resin, and potassium fluoroborate can be by-produced. The process is green and environmentally friendly, and the economic benefits are increased. In the present invention, the main components of the precipitate obtained by filtering after adding salt to the washing water are potassium fluoroborate and a small amount of potassium fluoride, and the potassium fluoride in the precipitate can be removed by water washing to obtain potassium fluoroborate products.

[0060] The present invention will be described below by way of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents and materials used in the examples are conventional methods, reagents and materials in the art unless otherwise specified. The raw material compounds in the examples can all be obtained through commercial channels.

[0061] In the examples, the determination method of the F - content is GB 7484-87 "Water Quality - Determination of Fluoride - Ion Selective Electrode Method". The determination method of the BF 4 - content is as follows: Using a PXD-3 digital ion meter, a 404 fluoroborate ion selective electrode and an 801 double-junction saturated calomel electrode (Jiangsu Electroanalytical Instrument Factory), measure the electrode potential Ec value at different standard concentrations C, make an Ec-logC standard curve graph, and then according to the measured electrode potential Ex value of the BF 4 - ion with unknown concentration, find the corresponding BF 4 - ion concentration point from the Ec-logC standard curve graph; Reagents: (1) Standard BF 4 - ion solution: Accurately weigh 0.1545 g of primary boric acid dried in vacuum below 60 °C into a small beaker, add 5 ml of hydrofluoric acid (48%), let it stand for more than 48 hours, and then prepare it into a 500 ml solution and store it in a plastic bottle; (2) 0.1 mol / L Na 2 SO 4 solution, adjust the pH = 4 with dilute sulfuric acid; Standard curve drawing: Respectively pipette 0.1, 0.5, 1.0, 5.0, 10.0 ml of the standard BF 4 - ion solution into 50 ml volumetric flasks, add 10 ml of 0.1 mol / L Na 2 SO4 The solution (with pH adjusted to 4) is diluted to the mark with distilled water, and then poured into small plastic beakers respectively. The potential is measured with a fluoborate ion-selective electrode under uniform stirring. Using logC as the abscissa and the corresponding millivolt value measured as the ordinate, a graph is plotted on semi-logarithmic paper to obtain the Ec-logC standard curve. The method for determining the ash content of indene resin is GB / T 2295-2008 "Methods for Determining Ash Content of Coking Solid Products".

[0062] In the indene resin polymerization solution used in the examples, the mass fraction of indene resin is 30%, the solvent is mesitylene, containing hydrofluoric acid and fluoboric acid, and the pH is 1.5.

[0063] Examples 1-3: Determine the washing temperature of the two-step water washing process

[0064] As Figure 1 shown, 200 g of indene resin polymerization solution is mixed with 100 g of water, stirred at 35 - 80 °C (80 °C, 55 °C, and 35 °C for Examples 1, 2, and 3 respectively) for 30 min, allowed to stand for layering and liquid separation to obtain wash water 1 and the oil phase; the oil phase is mixed with 100 g of water, stirred at 35 - 80 °C (80 °C, 55 °C, and 35 °C for Examples 1, 2, and 3 respectively) for 30 min, allowed to stand for layering and liquid separation to obtain wash water 2 and the oil phase; the oil phase is subjected to vacuum distillation to obtain solvent oil and indene resin. The F - content and BF 4 - content of wash water 1 and wash water 2 are measured, and whether there is an emulsified layer is observed. The results are shown in Table 1. 55 °C is the lowest washing temperature without an emulsified layer.

[0065] Table 1: F content, BF - content, and emulsification situation of wash water 1 and wash water 2 in Examples 1-3 4 - As can be seen from Table 1, the fluorine contents at the three washing temperatures are not very different. Considering the requirements of liquid separation without an emulsified layer during the water washing process and the energy consumption, the preferred washing temperature is 55 °C.

[0066]

[0067] It can be seen from Table 1 that the fluorine contents at the three washing temperatures are not very different. Considering the requirements of liquid separation without an emulsified layer during the water washing process and the energy consumption, the preferred washing temperature is 55 °C.

[0068] Example 4: Pilot test of wastewater recycling + reuse process

[0069] The two-step water washing process is used to remove the catalyst in the indene resin polymerization solution. As Figure 2 shown, multiple batches of water washing are carried out continuously. Each batch of water washing uses 200 g of indene resin polymerization solution, the washing temperature is 55 °C, and the washing time for each time is 30 min.

[0070] In the first batch of water washing, 200 g of indene resin polymerization liquid was mixed with 100 g of water, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the wash water 1 and the oil phase of the first batch; the oil phase was mixed with 100 g of water, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the wash water 2 and the oil phase of the first batch; the oil phase was subjected to vacuum distillation to obtain solvent oil and indene resin. The wash water 1 and wash water 2 of the first batch were reused in the second batch of water washing.

[0071] In the second batch of water washing, 200 g of indene resin polymerization liquid was mixed with the wash water 1 of the first batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the wash water 1 and the oil phase of the second batch; the oil phase was mixed with the wash water 2 of the first batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the wash water 2 and the oil phase of the second batch; the oil phase was subjected to vacuum distillation to obtain solvent oil and indene resin. The wash water 1 and wash water 2 of the second batch were reused in the third batch of water washing.

[0072] In the third batch of water washing, 200 g of indene resin polymerization liquid was mixed with the wash water 1 of the second batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the wash water 1 and the oil phase of the third batch; the oil phase was mixed with the wash water 2 of the second batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the wash water 2 and the oil phase of the third batch; the oil phase was subjected to vacuum distillation to obtain solvent oil and indene resin. At this time (the wash water 1 was reused 2 times), the BF 4 - concentration in the wash water 1 of the third batch was 25487.1 mg / L. Potassium chloride was added to the wash water 1 of the third batch according to the molar ratio of fluoborate ion to potassium ion of 1:0.9, stirred at room temperature for 30 min, filtered to obtain a precipitate containing potassium fluoborate and about 50 g of salt-treated wash water 1 (due to sampling and testing of the F - content and BF 4 - content, there was loss), and then the wash water 1 was supplemented with water to 100 g to obtain the wash water 1 after water supplementation. After retaining 10 g as a sample, the remaining 90 g was reused in the fourth batch of water washing. The wash water 2 of the third batch was about 60 g (due to sampling and testing of the F - content and BF 4 - content, there was loss), supplemented with water to 110 g to obtain the wash water 2 after water supplementation. After retaining 10 g as a sample, the remaining 100 g was reused in the fourth batch of water washing. The pH value of the indene resin prepared after catalyst removal in the third batch of water washing was 6.031, meeting the requirement of pH value 5.0 - 9.0.

[0073] In the fourth batch of water washing, 200 g of indene resin polymerization liquid was taken and mixed with the washing water 1 after adding supplementary water in the third batch. It was stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 1 and the oil phase in the fourth batch; the oil phase was mixed with the washing water 2 after adding supplementary water in the third batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 2 and the oil phase in the fourth batch; the oil phase was subjected to vacuum distillation to obtain solvent oil and indene resin. The pH value of the indene resin prepared after catalyst removal in the fourth batch of water washing was 6.322, meeting the requirement of pH value 5.0 - 9.0, and the ash content was 0.0616%, meeting the requirement of ash content < 0.5%.

[0074] The pH values of the catalyst-removed indene resins obtained in the first to fourth batches all met the requirement of pH value 5.0 - 9.0, and the ash contents all met the requirement of ash content < 0.5%.

[0075] Determine the F - content and BF 4 - content in the washing water during water washing of each batch. The results are shown in Table 2. In Example 4, the amount of water washing was less, and the detected values of the contents of fluoride ions and fluoroborate ions in the recycled water samples were on the high side.

[0076] Table 2: F in the washing water during water washing of each batch in Example 4 - content and BF 4 - content

[0077]

[0078] Example 5: Pilot-scale experiment on wastewater recycling + reuse process

[0079] A two-step water washing process was used to remove the catalyst from the indene resin polymerization liquid. As Figure 2 shown, multiple batches of water washing were carried out continuously. Each batch of water washing used 500 g of indene resin polymerization liquid, the water washing temperature was 55 °C, and the water washing time each time was 30 min.

[0080] In the first batch of water washing, 500 g of indene resin polymerization liquid was taken and mixed with 250 g of water, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 1 and the oil phase in the first batch; the oil phase was mixed with 250 g of water, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 2 and the oil phase in the first batch; the oil phase was subjected to vacuum distillation to obtain solvent oil and indene resin. The washing water 1 and washing water 2 in the first batch were reused in the second batch of water washing.

[0081] In the second batch of water washing, 500 g of indene resin polymerization liquid is taken and mixed with the washing water 1 of the first batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 1 of the second batch and the oil phase; the oil phase is mixed with the washing water 2 of the first batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 2 of the second batch and the oil phase; the oil phase is subjected to vacuum distillation to obtain solvent oil and indene resin. The washing water 1 and washing water 2 of the second batch are repeatedly applied to the third batch of water washing.

[0082] In the third batch of water washing, 500 g of indene resin polymerization liquid is taken and mixed with the washing water 1 of the second batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 1 of the third batch and the oil phase; the oil phase is mixed with the washing water 2 of the second batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 2 of the third batch and the oil phase; the oil phase is subjected to vacuum distillation to obtain solvent oil and indene resin. The washing water 1 and washing water 2 of the third batch are repeatedly applied to the fourth batch of water washing.

[0083] In the fourth batch of water washing, 500 g of indene resin polymerization liquid is taken and mixed with the washing water 1 of the third batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 1 of the fourth batch and the oil phase; the oil phase is mixed with the washing water 2 of the third batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 2 of the fourth batch and the oil phase; the oil phase is subjected to vacuum distillation to obtain solvent oil and indene resin. The washing water 1 and washing water 2 of the fourth batch are repeatedly applied to the fifth batch of water washing.

[0084] In the fifth batch of water washing, 500 g of indene resin polymerization liquid is taken and mixed with the washing water 1 of the fourth batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 1 of the fifth batch and the oil phase; the oil phase is mixed with the washing water 2 of the fourth batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 2 of the fifth batch and the oil phase; the oil phase is subjected to vacuum distillation to obtain solvent oil and indene resin. At this time (the washing water 1 has been applied 4 times), the BF 4 - concentration in the washing water 1 of the fifth batch is 34630.7 mg / L. Potassium chloride is added to the washing water 1 of the fifth batch according to the molar ratio of fluoborate ion to potassium ion of 1:0.5, stirred at room temperature for 30 min, filtered to obtain a precipitate containing potassium fluoborate and the washing water 1 after salt addition treatment (BF 4 - concentration is 2466.4 mg / L). The washing water 1 after salt addition treatment is recycled to the sixth batch of water washing. The washing water 2 of the fifth batch is recycled to the sixth batch of water washing. The pH value of the indene resin prepared after catalyst removal in the fifth batch of water washing is 5.72, meeting the requirement of pH value of 5.0 - 9.0.

[0085] In the sixth batch of water washing, 500 g of indene resin polymerization liquid was taken and mixed with the washing water 1 after salt addition treatment in the fifth batch. The mixture was stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 1 and the oil phase in the sixth batch. The oil phase was mixed with the washing water 2 in the fifth batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 2 and the oil phase in the sixth batch. The oil phase was subjected to vacuum distillation to obtain solvent oil and indene resin. The washing water 1 and washing water 2 in the sixth batch were repeatedly applied to the seventh batch of water washing.

[0086] In the seventh batch of water washing, 500 g of indene resin polymerization liquid was taken and mixed with the washing water 1 in the sixth batch. The mixture was stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 1 and the oil phase in the seventh batch. The oil phase was mixed with the washing water 2 in the sixth batch, stirred at 55 °C for 30 min, allowed to stand for layering and liquid separation to obtain the washing water 2 and the oil phase in the seventh batch. The oil phase was subjected to vacuum distillation to obtain solvent oil and indene resin.

[0087] The pH values of the de-catalyzed indene resin obtained in the first to seventh batches all met the requirement of pH value 5.0 - 9.0, and the ash content all met the requirement of ash content < 0.5%.

[0088] Determine the F - content and BF 4 - content in the washing water during the fifth and seventh batches of water washing. The results are shown in Table 3. The BF 4 - content in the washing water 1 of the seventh batch was 19331.6 mg / L. According to the data in Example 4, it was predicted that this wastewater could be reused 2 more times, and the BF 4 - content in the wastewater would reach approximately 30000 mg / L. After potassium salt precipitation treatment, it could still be reused, and this process was carried out in a cycle.

[0089] Table 3: F - content and BF 4 - content in the washing water during the fifth and seventh batches of water washing in Example 5

[0090]

Claims

1. A method for treating wastewater from indene resin production, characterized in that, the treatment method includes performing water washing on indene resin polymerization liquid in multiple batches, and the water washing of the indene resin polymerization liquid in the first batch includes the following steps: (1) First-step water washing: Add water to the indene resin polymerization liquid in the first batch, the weight of the water being 45%-55% of the weight of the indene resin polymerization liquid in the first batch, stir at the first stirring temperature for the first stirring time, stand for liquid separation, to obtain the polymerized liquid after the first-step water washing in the first batch and the first-step wash water in the first batch; (2) Second-step water washing: Add water to the polymerized liquid after the first-step water washing in the first batch, the weight of the water being 45%-55% of the weight of the indene resin polymerization liquid in the first batch, stir at the second stirring temperature for the second stirring time, stand for liquid separation, to obtain the polymerized liquid after the second-step water washing in the first batch and the second-step wash water in the first batch, and perform vacuum distillation on the polymerized liquid after the second-step water washing in the first batch to obtain solvent oil and indene resin; The water washing of the indene resin polymerization liquid in the second and subsequent batches includes the following steps: (1’)First step of water washing: If the BF content in the first-step wash water of the previous batch is < 30,000 mg / L, directly mix the indene resin polymerization liquid of this batch and the first-step wash water of the previous batch, stir for the first stirring time at the first stirring temperature, let it stand for liquid separation, and obtain the polymerization liquid after the first-step water washing of this batch and the first-step wash water of this batch; if the BF content in the first-step wash water of the previous batch is ≥ 30,000 mg / L, then according to the molar ratio of BF and K in the potassium salt being 1:(0.5 - 0.9), add potassium salt to the first-step wash water of the previous batch, stir for the third stirring time at the third stirring temperature, filter, obtain the first-step wash water after treatment of the previous batch and the precipitate containing potassium fluoroborate, then mix the indene resin polymerization liquid of this batch and the first-step wash water after treatment of the previous batch, stir for the first stirring time at the first stirring temperature, let it stand for liquid separation, and obtain the polymerization liquid after the first-step water washing of this batch and the first-step wash water of this batch; 4 - content < 30,000 mg / L, directly mix the indene resin polymerization liquid of this batch and the first-step wash water of the previous batch, stir for the first stirring time at the first stirring temperature, let it stand for liquid separation, and obtain the polymerization liquid after the first-step water washing of this batch and the first-step wash water of this batch; if the BF content in the first-step wash water of the previous batch is 4 - content ≥ 30,000 mg / L, then according to the BF in the first-step wash water of the previous batch 4 - and K in the potassium salt + the molar ratio is 1:(0.5 - 0.9), add potassium salt to the first-step wash water of the previous batch, stir for the third stirring time at the third stirring temperature, filter, obtain the first-step wash water after treatment of the previous batch and the precipitate containing potassium fluoroborate, then mix the indene resin polymerization liquid of this batch and the first-step wash water after treatment of the previous batch, stir for the first stirring time at the first stirring temperature, let it stand for liquid separation, and obtain the polymerization liquid after the first-step water washing of this batch and the first-step wash water of this batch; (2’)Second step of water washing: If the BF content in the second-step wash water of the previous batch is < 30,000 mg / L, directly mix the polymerized liquid after the first-step water washing of this batch and the second-step wash water of the previous batch, stir for the second stirring time at the second stirring temperature, stand still for liquid separation, to obtain the polymerized liquid after the second-step water washing of this batch and the second-step wash water of this batch; if the BF content in the second-step wash water of the previous batch is ≥ 30,000 mg / L, then according to the molar ratio of BF and K in the potassium salt being 1:(0.5 - 0.9), add potassium salt to the second-step wash water of the previous batch, stir for the third stirring time at the third stirring temperature, filter, to obtain the second-step wash water after treatment of the previous batch and the precipitate containing potassium fluoroborate, then mix the polymerized liquid after the first-step water washing of this batch and the second-step wash water after treatment of the previous batch, stir for the second stirring time at the second stirring temperature, stand still for liquid separation, to obtain the polymerized liquid after the second-step water washing of this batch and the second-step wash water of this batch, perform vacuum distillation on the polymerized liquid after the second-step water washing of this batch, to obtain solvent oil and indene resin; 4 - content < 30,000 mg / L, then directly mix the polymerized liquid after the first-step water washing of this batch and the second-step wash water of the previous batch, stir for the second stirring time at the second stirring temperature, stand still for liquid separation, to obtain the polymerized liquid after the second-step water washing of this batch and the second-step wash water of this batch; if the BF content in the second-step wash water of the previous batch is ≥ 30,000 mg / L, then according to the molar ratio of BF and K in the potassium salt being 1:(0.5 - 0.9), add potassium salt to the second-step wash water of the previous batch, stir for the third stirring time at the third stirring temperature, filter, to obtain the second-step wash water after treatment of the previous batch and the precipitate containing potassium fluoroborate, then mix the polymerized liquid after the first-step water washing of this batch and the second-step wash water after treatment of the previous batch, stir for the second stirring time at the second stirring temperature, stand still for liquid separation, to obtain the polymerized liquid after the second-step water washing of this batch and the second-step wash water of this batch, perform vacuum distillation on the polymerized liquid after the second-step water washing of this batch, to obtain solvent oil and indene resin; 4 - content ≥ 30,000 mg / L, then according to the molar ratio of BF and K in the potassium salt being 1:(0.5 - 0.9), add potassium salt to the second-step wash water of the previous batch, stir for the third stirring time at the third stirring temperature, filter, to obtain the second-step wash water after treatment of the previous batch and the precipitate containing potassium fluoroborate, then mix the polymerized liquid after the first-step water washing of this batch and the second-step wash water after treatment of the previous batch, stir for the second stirring time at the second stirring temperature, stand still for liquid separation, to obtain the polymerized liquid after the second-step water washing of this batch and the second-step wash water of this batch, perform vacuum distillation on the polymerized liquid after the second-step water washing of this batch, to obtain solvent oil and indene resin; 4 - and K in the potassium salt is 1:(0.5 - 0.9), add potassium salt to the second-step wash water of the previous batch, stir for the third stirring time at the third stirring temperature, filter, to obtain the second-step wash water after treatment of the previous batch and the precipitate containing potassium fluoroborate, then mix the polymerized liquid after the first-step water washing of this batch and the second-step wash water after treatment of the previous batch, stir for the second stirring time at the second stirring temperature, stand still for liquid separation, to obtain the polymerized liquid after the second-step water washing of this batch and the second-step wash water of this batch, perform vacuum distillation on the polymerized liquid after the second-step water washing of this batch, to obtain solvent oil and indene resin; + content ≥ 30,000 mg / L, then according to the molar ratio of BF and K in the potassium salt being 1:(0.5 - 0.9), add potassium salt to the second-step wash water of the previous batch, stir for the third stirring time at the third stirring temperature, filter, to obtain the second-step wash water after treatment of the previous batch and the precipitate containing potassium fluoroborate, then mix the polymerized liquid after the first-step water washing of this batch and the second-step wash water after treatment of the previous batch, stir for the second stirring time at the second stirring temperature, stand still for liquid separation, to obtain the polymerized liquid after the second-step water washing of this batch and the second-step wash water of this batch, perform vacuum distillation on the polymerized liquid after the second-step water washing of this batch, to obtain solvent oil and indene resin; The first stirring temperature is 55-60°C, the second stirring temperature is 55-60°C, and the third stirring temperature is 20-30°C.

2. The treatment method according to claim 1, characterized in that, the potassium salt is selected from one or more of potassium chloride, potassium sulfate, potassium nitrate and potassium alum.

3. The treatment method according to claim 1, characterized in that, the potassium salt is potassium chloride.

4. The treatment method according to claim 1, characterized in that, the first stirring time is 25-35 min, the second stirring time is 25-35 min, and the third stirring time is 25-35 min.

5. The treatment method according to claim 1, characterized in that, the indene resin polymerization liquid includes indene resin, solvent, hydrofluoric acid and fluoboric acid.

6. The treatment method according to claim 5, characterized in that, the pH value of the indene resin polymerization liquid is 1-2.

7. The treatment method according to claim 5, characterized in that, the solvent includes one or two selected from xylene and trimethylbenzene.

8. The treatment method according to claim 5, characterized in that, in the indene resin polymerization liquid, the mass fraction of indene resin is 20%-30%.

9. The treatment method according to claim 1, characterized in that, the mass of the indene resin polymerization liquid treated in each batch is more than 500 g.

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