Device and method for improving the yield of polycarboxylate superplasticizer and preventing pollution

Abstract

The present invention discloses a device and method for improving the yield of polycarboxylate superplasticizer and preventing pollution, which includes an alkali preparation tank, first and second premixing tanks, a reaction kettle, a reflux condenser, a wire mesh trap, an absorption tower, an alkali tank and a tail gas pipeline; the alkali preparation tank is connected to the alkali tank, the first premixing tank and the second premixing tank are connected to the reaction kettle, a reflux condenser is arranged at the top of the reaction kettle, and a wire mesh trap is arranged at the bottom of the reflux condenser; an alkali tank is arranged at the bottom of the absorption tower, and the alkali tank is connected to the reaction kettle. By setting the tail gas pipeline and the absorption tower, the dust and waste gas generated during the preparation of alkali solution, premixing and reaction enter the upper part of the alkali tank through the tail gas recovery pipeline, and then rise into the tail gas absorption tower, pass through the packing layer, and carry out countercurrent absorption with the alkali absorption liquid sprayed from the top of the tail gas tower, preventing harmful gases and dust in the reaction system from entering the atmosphere and causing air pollution, and realizing the improvement of the reaction yield of polycarboxylate water reducer.

Description

Technical Field

[0001] The present invention belongs to the technical field of the production of water reducing agents for concrete, and relates to a device and method for improving the yield of polycarboxylate superplasticizers and preventing pollution. Background Art

[0002] Water reducing agents are an essential chemical building material product for concrete construction in the world today. In recent years, with the continuous rapid economic development, the scale of infrastructure investment has been unprecedented. Construction projects such as municipal infrastructure, high-speed railways, highways, and water conservancy projects have been increasing continuously, and all of these are inseparable from concrete. And as the "monosodium glutamate" of concrete, water reducing agents are even more indispensable. Commercial concrete and high-performance concrete cannot be formulated at all without high-performance water reducing agents.

[0003] Water reducing agents (including slump retaining water reducing agents) are chemical substances that can reduce the amount of mixing water in concrete under the condition of the same slump of the concrete mixture. Water reducing agents are divided into three types: ordinary water reducing agents, high-efficiency water reducing agents, and high-performance water reducing agents. Ordinary water reducing agents are mainly based on lignosulfonate calcium and lignosulfonate sodium, which are the first-generation water reducing agents with a relatively small water reduction rate, generally about 10%, and are currently basically phased-out products; the main component of the second-generation water reducing agent is naphthalene sulfonate water reducing agent, and the water reduction rate is generally about 20%; the main component of the third-generation high-performance water reducing agent is polycarboxylate, and the water reduction rate is greater than 25%.

[0004] Naphthalene-based high-efficiency water reducing agents use industrial naphthalene and industrial concentrated sulfuric acid in production, and the reaction needs to be carried out at high temperature. Due to the source of naphthalene and environmental protection problems and high energy consumption in production, as well as the corrosiveness of concentrated sulfuric acid to equipment, and the performance defects of naphthalene-based products themselves, the mainstream of international research and development of concrete water reducing agents is high-performance polycarboxylate water reducing agents. High-performance polycarboxylate water reducing agents have excellent molecular designability and have irreplaceable advantages in the manufacturing processes of high-strength concrete, pumped concrete, self-compacting concrete, etc., and are expected to completely replace naphthalene-based high-efficiency water reducing agents in the future. At the same time, due to the use of redox reaction systems, high-performance polycarboxylate water reducing agents can be synthesized at room temperature, overcoming the high energy consumption problem of naphthalene-based water reducing agents, saving energy, reducing pollution and emissions.

[0005] The main raw materials for the synthesis of polycarboxylate superplasticizers include methallyl polyoxyethylene ether (commonly known as the macromonomer) or other allyl polyoxyethylene ethers with terminal hydroxyl groups, small molecules with double bonds such as acrylic acid (commonly known as the small monomer), acrylate, reducing agents such as VC or sodium hypophosphite, oxidizing agents such as hydrogen peroxide or ammonium persulfate, chain transfer agents such as mercaptopropionic acid, mercaptoacetic acid, mercaptoethanol, and other functional small monomers. Methallyl polyoxyethylene ether, commonly known as the macromonomer, is a powdery white solid. Due to the presence of unsaturated double bonds, it provides the activity for the polymerization reaction. The differences between different grades are mainly the number of carbon atoms in the molecule (mainly C4, C5, C6 carbon chains) and the different terminal hydroxyl groups, resulting in different water-reducing rates and slump retention properties of the concrete prepared with the synthesized polycarboxylate superplasticizer. Functional small monomers mainly provide different functional groups, endowing the superplasticizer with different properties, such as providing slump retention, anti-clay, and water retention properties for the concrete.

[0006] The commonly used synthesis process for polycarboxylate superplasticizers is as follows: Add the specified amount of bottom water into the reaction kettle, pour the specified amount of methallyl polyoxyethylene ether (macromonomer) through the manhole, stir and dissolve it, and then add hydrogen peroxide; Prepare the dropping solution A by mixing VC, mercaptopropionic acid, and deionized water in proportion, and prepare the dropping solution B by mixing acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, functional monomers, and water; At room temperature, simultaneously drop the dropping solutions A and B into the reaction kettle through the high-level tank. The dropping time is generally 2 - 3 hours. After dropping, keep the temperature for 0.5 - 1 hour, then add 30% of the alkali solution required by the formula to neutralize and complete the synthesis reaction. Finally, add the specified amount of water to adjust the solid content of the product. Since hydrogen peroxide and VC are added during the reaction, the reaction proceeds under redox conditions, enabling the synthesis reaction to start at room temperature. During the reaction process, due to the heat released by the polymerization reaction, the reaction temperature will automatically rise, and the temperature can reach a maximum of 50 - 60 °C at the end of the reaction. Therefore, the reaction conditions for polycarboxylate superplasticizers are mild, energy-saving, and have less emissions. Currently, the synthesis methods of high-performance polycarboxylate superplasticizers at home and abroad are basically the same, and basically all use the low-temperature synthesis process of the redox system, while the high-temperature synthesis process has been basically phased out. The differences in the formulas of each manufacturer are that the properties of the finished products synthesized by different acid-ether ratios, different dosages of reducing agents and oxidizing agents, different varieties and dosages of chain transfer agents, and different types and dosages of functional small monomers are different.

[0007] Although the low-temperature process is used in the synthesis of polycarboxylate superplasticizer, with low emissions and less pollution, there are still certain exhaust emissions and dust pollution. Moreover, due to emissions and pollution, the reaction raw materials leak, resulting in a decrease in the reaction yield. The main pollution links are as follows: ① During the preparation of the chain transfer agent such as mercaptopropionic acid, mercaptoacetic acid, and mercaptopropanol in the premixing tank, due to equipment defects, they volatilize into the air. Mercaptopropionic acid has a strong sulfide odor and is toxic. Even a small amount of volatilization can cause headaches and discomfort, endangering the health of workers; ② When preparing the acrylic acid and acrylate dropping solutions in the premixing tank, acrylic acid and acrylate are likely to volatilize into the air. Acrylic acid is chemically active and has a strong irritation to human skin and respiratory tract. It is a class 3 carcinogen determined by the World Health Organization; ③ During the process of manually pouring the macromonomer into the reaction kettle through the manhole before the synthesis reaction, since the macromonomer is in a fine powder state, when it is poured from the packaging bag into the reaction kettle, the powder particles will fly up, causing dust pollution. At the same time, the lost macromonomer will also cause a decrease in the yield; ④ The mercaptopropionic acid dropping solution and acrylic acid dropping solution volatilize during the dropping process, especially the volatilization accelerates after the reaction temperature rises, polluting the air; ⑤ During the dropping process, acrylic acid flows down along the wall of the reaction kettle, or splashes onto the wall of the kettle and the stirring shaft, reacting with the chain transfer agent or reacting under the action of an oxidant to form a gel-like acrylic acid homopolymer or a polymer of acrylic acid and hydroxyethyl acrylate. This homopolymer or polymer is a gel-like water-absorbing resin material, which will grow on the wall of the kettle or the stirrer, reducing the reaction yield. It is necessary to frequently manually clean the homopolymer on the wall of the kettle or the stirrer, which is time-consuming and laborious, and also generates solid waste pollution to the environment. Summary of the Invention

[0008] To overcome the pollution problems of waste gas, dust, and solid waste in the synthesis process of polycarboxylate superplasticizer in the prior art, and the resulting problem of decreased synthesis yield, the object of the present invention is to propose a device and method for improving the yield of polycarboxylate superplasticizer and preventing pollution.

[0009] To solve the above problems, the present invention adopts the following technical solutions:

[0010] A device for improving the yield of polycarboxylate superplasticizer and preventing pollution, comprising an alkali preparation tank, a first premixing tank, a second premixing tank, a reaction kettle, a reflux condenser, a wire mesh collector, a brine tank, an absorption tower, an alkali tank, and a tail gas pipeline;

[0011] Among them, the alkali preparation tank is connected to the alkali tank, the first premixing tank and the second premixing tank are connected to the reaction kettle. A reflux condenser is arranged at the top of the reaction kettle, a wire mesh trap is arranged at the bottom of the reflux condenser, a brine inlet and a brine outlet are arranged on the reflux condenser, the outlet of the brine tank is connected to the brine inlet, and the brine outlet is connected to the inlet of the brine tank; An alkali tank is arranged at the bottom of the absorption tower, the alkali tank is connected to the reaction kettle, and the alkali preparation tank, the first premixing tank, the second premixing tank, the alkali tank and the reflux condenser are connected to the tail gas pipeline.

[0012] Further, a caustic soda inlet, a deionized water inlet and a tail gas outlet are arranged at the top of the alkali preparation tank, an outlet is arranged at the bottom of the alkali preparation tank, a first feed pipe, a deionized water inlet and a tail gas outlet are arranged at the top of the first premixing tank, a second feed pipe, a deionized water inlet and a tail gas outlet are arranged at the top of the second premixing tank, and outlets are arranged at the bottoms of the first premixing tank and the second premixing tank; The first feed pipe extends into the bottom of the first premixing tank, and the second feed pipe extends into the bottom of the second premixing tank.

[0013] Further, the first premixing tank is connected to the reaction kettle through a first discharge pump and a second high-level tank; The second premixing tank is connected to the reaction kettle through a second discharge pump and a first high-level tank.

[0014] Further, a reflux port is arranged at the top of the reaction kettle, the wire mesh trap is arranged below the reflux port, the reflux condenser is arranged above the reflux port, and a deionized water inlet is opened at the upper part of the reflux condenser;

[0015] Vent pipes connected to the tail gas pipeline are arranged at the tops of the alkali preparation tank, the first premixing tank, the second premixing tank, the first high-level tank and the second high-level tank and the reflux condenser.

[0016] Further, the tail gas pipeline is connected to the alkali tank through a centrifugal fan; The alkali tank is connected to the reaction kettle through an alkali liquor circulation pump.

[0017] Further, a refrigerator is also connected to the brine tank.

[0018] Further, a first raw material addition pipe is arranged on the first premixing tank, and the first raw material addition pipe is inserted into the deionized water liquid level in the first premixing tank through a head; A second raw material addition pipe is arranged on the second premixing tank, and the second raw material addition pipe is inserted into the deionized water liquid level in the second premixing tank through a head; A dropping feed pipe is arranged on the reaction kettle, and the dropping feed pipe is inserted into the bottom water liquid level in the reaction kettle; The reflux condenser is connected to the wire mesh trap, and the reflux condenser is installed in a vertical or horizontal installation manner.

[0019] Further, the alkali preparation tank is connected to the alkali tank through an alkali liquor pump;

[0020] Weight sensors are arranged at the bottoms of the alkali preparation tank, the first premixing tank, the second premixing tank, the first high-level tank, the second high-level tank and the alkali tank.

[0021] Further, the wire mesh trap is a trap filled with wire mesh packing, ceramic or plastic packing rings inside.

[0022] A method for improving the yield of polycarboxylate superplasticizer and preventing pollution based on the device described above, comprising the following steps:

[0023] Step 1: Turn on the fan to make the tail gas pipeline in a negative pressure state. Add deionized water into the alkali preparation tank and make the alkali preparation tank in a negative pressure state. Add flake alkali into the alkali preparation tank, stir and dissolve it, and then pump it into the alkali tank.

[0024] Step 2: Make the first premixing tank in a negative pressure state. Add deionized water into the first premixing tank, add a reducing agent and a chain transfer agent into the first premixing tank, stir evenly, and obtain the first discharge.

[0025] Step 3: Make the second premixing tank in a negative pressure state, start the stirring of the second premixing tank, open the deionized water valve of the second premixing tank, add acrylic acid or hydroxyethyl acrylate into the second premixing tank, and stir evenly to obtain the second discharge.

[0026] Step 4: Add bottom water to the reaction kettle through the tail gas process channel of the reflux condenser to make the reaction kettle in a negative pressure state. Start the stirring of the reaction kettle, add methallyl polyoxyethylene ether into the reaction kettle, stir evenly, add an oxidizing agent, stir evenly, dropwise add the first discharge and the second discharge, then keep warm, add deionized water through the reflux condenser and the wire mesh trap, adjust the solid content, and add an alkali solution for neutralization reaction to obtain the superplasticizer.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] By setting up the tail gas pipeline, the alkali preparation tank, the first premixing tank, the second premixing tank, the alkali tank, the reflux condenser is connected to the tail gas pipeline, the waste gas and dust generated in the production process of polycarboxylate superplasticizer can be recycled and treated to prevent environmental pollution of the tail gas. By installing a wire mesh trap at the reflux port of the reaction kettle to capture the macromonomer dust, prevent dust pollution, reduce the loss of macromonomer, and improve the reaction yield. By installing a reflux condenser at the reflux port of the reaction kettle to cool and reflux the small amount of gas and water vapor volatilized during the reaction process, significantly reduce the amount of volatilized gas generated, and reduce the amount of waste gas. By setting up the tail gas pipeline and the absorption tower, the dust and waste gas generated during the preparation of alkali solution, premixing, and reaction process enter the upper part of the alkali tank through the tail gas recovery pipeline, then enter the tail gas absorption tower and rise, pass through the packing layer, and perform countercurrent absorption with the alkali absorption liquid sprayed from the top of the tail gas tower to prevent harmful gases and dust in the reaction system from entering the atmosphere and causing air pollution.

[0029] Further, the first feed pipe and the second feed pipe of the premixing tank of the present invention are inserted into the bottom of the tank and buried below the liquid level of the deionized water for batching, so that chain transfer agents such as volatile mercaptopropionic acid and acrylic acid are rapidly diluted. Since the concentration is greatly decreased, the partial pressure of the volatile substances in the gas phase is reduced, and the volatilization amount of the raw materials is greatly reduced. At the same time, it can prevent the splash when the materials in the existing process are added into the tank and fall onto the liquid surface, which increases the volatilization area of the liquid and accelerates the volatilization of the liquid, and reduces the amount of volatile waste gas from the process.

[0030] Further, the dropping feed pipe of the reaction kettle extends below the bottom water liquid level of the reaction kettle, reducing the concentration of the dropping liquid, preventing the harmful gas volatilization caused by the dropping liquid flowing down along the kettle wall or directly splashing onto the liquid surface, and at the same time avoiding the phenomenon that when the dropping liquid of acrylic acid or hydroxyethyl acrylate in the existing process flows down along the kettle wall or directly splashes onto the liquid surface, under the oxidant atmosphere, solid gel-like substances generated by the self-polymerization of acrylic acid or hydroxyethyl acrylate are formed on the kettle wall and the stirring shaft, and finally solid waste is generated, preventing the generation of solid waste, and improving the yield of the synthesis reaction and the economic benefit.

[0031] Further, the wire mesh trap is filled with stainless steel wire mesh, or ceramic or plastic packing rings. When the solid macromonomer raw materials are added to the reaction kettle through the manhole, under the negative pressure of the tail gas pipeline, most of the solid dust generated during the falling process of the raw materials is sucked into the wire mesh trap and trapped by the trap. The trapped dust is dissolved and washed into the reaction kettle by the reflux liquid generated during the reaction process to continue to participate in the reaction, improving the yield of the macromonomer and reducing the production cost, and at the same time greatly reducing the amount of dust gas.

[0032] Further, a reflux condenser is arranged at the reflux port of the reaction kettle, and the shell side of the reflux condenser is cooled by circulating frozen brine, so that a small amount of volatile substances such as chain transfer agents, acrylic acid or hydroxyethyl acrylate and volatile water volatilized during the reaction process are condensed and refluxed into the reaction kettle to continue to participate in the reaction, improving the reaction yield of these substances and reducing the amount of harmful waste gas at the same time.

[0033] In the present invention, the fresh alkali solution prepared in the alkali preparation tank first enters the alkali tank and serves as the spray liquid of the tail gas absorption tower, absorbing waste gas and dust first during the batching and reaction processes, and then being put into the reaction kettle for neutralization reaction after the reaction is completed. The high-concentration alkali solution has a high absorption efficiency for acidic mercaptopropionic acid and acrylic acid. At the same time, since the alkali solution is used for neutralization reaction after each reaction is completed, the concentration of the absorbed substances in the alkali solution recycled by the tail gas absorption tower will not accumulate, preventing the problem that the absorption liquid concentration decreases and the absorbed substances are enriched during the long-term recycling of the alkali solution, resulting in difficulties in the subsequent treatment of the absorption liquid, and no new waste liquid needs to be treated. The present invention makes full use of various synthesis raw materials, so it improves the yield of the reactants, manifested in the increase of the solid content of the reactants and the improvement of the economic benefit. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic structural diagram of the device of the present invention.

[0035] Figure 2 It is a schematic structural diagram of a wire mesh trap; wherein, (a) is a top view, (b) is a sectional view, and (c) is a schematic connection diagram of the wire mesh trap with a reflux condenser and a reaction kettle.

[0036] In the figure, 1 is an alkali preparation tank, 2 is a first premixing tank, 3 is a second premixing tank, 4 is a liquid caustic soda pump, 5 is a first discharge pump, 6 is a second discharge pump, 7 is a first elevated tank, 8 is a second elevated tank, 9 is a reaction kettle, 10 is a reflux condenser, 11 is a wire mesh trap, 12 is a coolant circulation pump, 13 is a brine tank, 14 is a refrigerator, 15 is a centrifugal fan, 16 is a tail gas absorption tower, 17 is an alkali tank, 18 is an alkali liquid circulation pump, 19 is a tail gas pipeline, 20 is a caustic soda inlet, 21 is a first feed pipe, 22 is a second feed pipe, 23 is a cylinder body, 24 is a flange, 25 is a filter hole, and 26 is a connecting bolt. DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention will be described in detail below with reference to the accompanying drawings.

[0038] The existing common process for preparing water reducing agents is to control the length of the main chain and side chains of polycarboxylate water reducing agents by adjusting the ratio of acid (commonly known as small monomer - acrylic acid or its isomers) to ether (commonly known as large monomer - terminal hydroxyl polyoxyethylene ether), control the molecular weight, slump retention performance, and adaptability of the synthesized product by adjusting the amount of reaction bottom water, control the reaction temperature and molecular weight distribution by adjusting the amounts of reducing agent and oxidizing agent, control the molecular weight of the product by adjusting the amount, concentration, and dropping time of the chain transfer agent, adjust the concentration of the small monomer, and control the reaction time to prevent the reaction temperature from rising too fast and causing explosion polymerization. Adjusting the reaction dropping time can obtain a higher yield under the best economic conditions.

[0039] The present invention uses the alkali solution for adjusting the pH value after the synthesis reaction as the circulating absorption liquid of the waste gas absorption tower, which can make the circulating liquid of each reaction at a high concentration, improve the waste gas absorption effect, and at the same time prevent the concentration of the alkali solution from decreasing due to long-term circulation and the enrichment of the absorbed substances, resulting in difficulties in the subsequent treatment of the absorption liquid. The present invention improves the reaction yield, reduces the emission of harmful gases, and reduces the pollution of dust and solid waste during the production process.

[0040] The amount of the alkali solution in the present invention is the amount of caustic soda required to neutralize the polycarboxylic acid high polymer generated by the reaction to a pH value of 6 - 7 according to requirements, and its prepared mass concentration is between 30% - 40%. In the existing process, after the alkali solution is prepared, it is added to the reaction kettle for neutralization after the reaction is completed.

[0041] SeeFigure 1 An apparatus for improving the yield of polycarboxylate superplasticizer and preventing pollution according to the present invention includes an alkali preparation tank 1, a first premixing tank 2, a second premixing tank 3, a liquid caustic pump 4, a first discharge pump 5, a second discharge pump 6, a first elevated tank 7, a second elevated tank 8, a reaction kettle 9, a reflux condenser 10, a wire mesh trap 11, a coolant circulation pump 12, a brine tank 13, a refrigerator 14, a centrifugal fan 15, a tail gas absorption tower 16, an alkali tank 17 and an alkali liquor circulation pump 18. Among them, the top of the alkali preparation tank 1 is provided with a caustic soda inlet 20, a deionized water inlet and a tail gas outlet, and the bottom of the alkali preparation tank 1 is provided with an outlet. The top of the first premixing tank 2 is provided with a first feed pipe (mercapto propionic acid addition pipe) 21, a deionized water inlet and a tail gas outlet. The top of the second premixing tank 3 is provided with a second feed pipe (acrylic acid addition pipe) 22, a deionized water inlet and a tail gas outlet. The bottoms of the first premixing tank 2 and the second premixing tank 3 are provided with outlets. The top of the reaction kettle 9 is provided with a reflux port, and a wire mesh trap 11 is arranged below the reflux port. The wire mesh trap 11 is connected with a reflux condenser 10. The upper tube side of the reflux condenser 10 is provided with a tail gas outlet and a deionized water inlet, and the shell side of the reflux condenser 10 is provided with a brine inlet and a brine outlet. The outlet of the brine tank 13 is connected to the brine inlet of the reflux condenser 10 through a coolant circulation pump, and the brine outlet of the reflux condenser 10 is connected to the inlet of the brine tank 13. The brine tank 13 is also connected with a refrigerator 14. The bottom of the tail gas absorption tower 16 is provided with an alkali tank 17. The tail gas pipeline 19 is connected with a centrifugal fan 15, and the centrifugal fan 15 is connected with the air inlet of the alkali tank 17. The outlet of the alkali tank 17 is connected to the reaction kettle 9 through an alkali liquor circulation pump 18.

[0042] The first addition pipe 21 on the first premixing tank 2 is inserted into the deionized water liquid level for dilution in the first premixing tank 2 through the head, and the second addition pipe 22 of the second premixing tank 3 is inserted into the deionized water liquid level for dilution in the second premixing tank 3 through the head. The dosage of deionized water is determined by formula calculation. Vent pipes connected to the tail gas pipeline 19 are provided at the tops of the alkali preparation tank 1, the first premixing tank 2, the second premixing tank 3, the first high-level tank 7, the second high-level tank 8, and the reflux condenser 10. All the tail gas outlets are connected to the tail gas pipeline 19 through the vent pipes. The dropping feed pipe of the reaction kettle 9 is inserted into the bottom water liquid level in the reaction kettle 9 through the head, and the dosage of the bottom water is determined by formula calculation. The tube side of the reflux condenser 10 is connected to the wire mesh demister 11. The reflux condenser 10 is installed vertically to ensure that the condensed reflux liquid can flow back into the reaction kettle 9. The deionized water inlet of the reflux condenser 10 is connected to the deionized water inlet pipeline, so that the bottom water required for the reaction in the reaction kettle 9 and the process water added after the reaction can wash the reflux condenser 10 and the wire mesh demister 11 to prevent material residues in the reflux condenser 10 and the wire mesh demister 11. The alkali preparation tank 1 is connected to the alkali tank 17 through the alkali liquid pump 4. The prepared alkali liquid in the alkali preparation tank 1 is transported to the alkali tank 17 under the tail gas absorption tower 16 through the alkali liquid pump 4. The alkali liquid circulation pump 18 pumps the alkali liquid into the tail gas absorption tower 16 for spray circulation absorption. After the reaction, the alkali liquid is transported to the reaction kettle 9 through the pipeline to neutralize the synthesized polycarboxylate superplasticizer mother liquor; the tail gas absorption tower 16 can be a plate tower or a packed tower, and a packed tower is preferably used. The packing in the tower can be selected from Raschig rings, Pall rings, cascade rings, corrugated plates and other packings.

[0043] Weight sensors are provided at the bottoms of the alkali preparation tank 1, the first premixing tank 2, the second premixing tank 3, the first high-level tank 7, the second high-level tank 8 and the alkali tank 17.

[0044] The materials of the alkali dosing tank 1, the first premixing tank 2, the first elevated tank 7 and the second elevated tank 8 can be polypropylene, polyethylene, glass-lined or stainless steel, etc., and stainless steel is preferably used; the stirring forms of the first premixing tank 2 and the second premixing tank 3 can be paddle type, frame type, propeller type, and the reactor 9 can be made of stainless steel or glass-lined. The reactor 9 is cooled or heated by a jacket or a coil; the stirring paddle in the reactor 9 is preferably made of stainless steel, and the stirring form can be paddle type, frame type, propeller type, and the stirring speed should be controlled between 50 - 80 revolutions per minute; the wire mesh trap 11 is preferably made of stainless steel for easy processing and installation, and the packing in it can be stainless steel wire mesh, ceramic packing rings or plastic packing rings; the reflux condenser 10 is preferably made of stainless steel. To reduce investment, the tube side (tail gas channel), tube sheet and head of the reflux condenser 10 are preferably made of stainless steel, and the shell side uses carbon steel; the materials of the alkali tank 17 and the tail gas absorption tower 16 can be polypropylene, fiberglass, stainless steel, glass-lined, and polypropylene is preferably used; the packing of the tail gas absorption tower 16 can be stainless steel, polyethylene or ceramic materials, and polyethylene material is preferably used; the materials of the centrifugal fan 15 can be fiberglass, polypropylene or carbon steel lined with plastic, and polypropylene is preferably used; the materials of the material pipeline and the tail gas pipeline can be stainless steel, PVC or PPR, the material pipeline preferably uses PPR, and the tail gas pipeline preferably uses PVC.

[0045] When producing water reducing agents, open the tail gas valve of the alkali dosing tank 1. Utilize the negative pressure in the tail gas pipeline to make the air near the charging manhole of the alkali dosing tank 1 flow into the alkali dosing tank 1, so that the dust generated during the process of the solid caustic soda (sodium hydroxide) added through the manhole falling into the tank body will not overflow outside the manhole, but is inhaled into the tail gas absorption tower 16 through the tail gas pipeline, and is absorbed by spraying to prevent dust hazards and improve the utilization rate of caustic soda. The best concentration of the prepared alkali solution is 30% - 40% by mass concentration, and the dosage of the prepared alkali is determined according to the requirements of the water reducing agent formula.

[0046] The first premixing tank 2 is a container for preparing deionized water, chain transfer agent, and reducing agent. When producing water reducing agents, open the tail gas valve of the first premixing tank 2. Utilize the negative pressure of the tail gas pipeline to make the volatile raw material gas generated during batching enter the tail gas absorption tower 16, and neutralize and absorb the acid and alkali through alkali solution spraying to prevent air pollution. The feed inlets of mercaptopropionic acid, mercaptoacetic acid, and mercaptoethanol in the first premixing tank 2 are inserted into the bottom of the premixing tank through pipelines, so that they are buried in the batching water required by the formula. In this way, the raw materials sucked in by the self-priming pump enter the premixing tank after passing through the liquid level of the batching water, greatly diluting and reducing the concentration of the volatile chain transfer agent, reducing its volatility, and reducing the large amount of volatile gas generated by splashing when directly entering the premixing tank in the existing process, achieving the purpose of reducing waste gas and protecting the health of production personnel. To prevent the feed pipe from colliding with the stirrer or the liquid rotation from causing violent shaking of the feed pipe and damage, the feed pipe should be as close to the kettle wall as possible and fixed on the kettle wall.

[0047] The second premixing tank 3 is a preparation container for small monomers such as deionized water, acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, and isomeric esters required by the formula. During production, the tail gas valve is opened, and the negative pressure of the tail gas pipeline 19 is utilized to enable the volatile raw material gases generated during batching to enter the tail gas absorption tower 16. In the tail gas absorption tower 16, they are neutralized and absorbed by alkali solution spraying to prevent air pollution. The feeding ports of small monomers such as acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, and isomeric esters are inserted into the bottom of the second premixing tank 3 through the feeding pipes, so that they are buried in the batching water required by the formula. In this way, the raw materials sucked by the self-priming pump enter the second premixing tank 3 under the liquid level of the batching water, greatly diluting and reducing the concentration of the volatile small monomers, reducing their volatility, and preventing a large amount of volatile gases from being generated due to splashing when directly entering the premixing tank in the existing process, achieving the purpose of reducing waste gas and protecting the health of production personnel. To prevent the feeding pipes from colliding with the stirrer or being affected by the liquid rotation, causing the feeding pipes to shake violently and be damaged, the feeding pipes should be as close as possible to the wall of the second premixing tank and fixed on the wall of the second premixing tank.

[0048] A dropping feeding pipe is arranged in the reaction kettle 9. The discharging pipe of the first high-level tank 7 and the discharging pipe of the second high-level tank 8 are connected to the dropping feeding pipe of the reaction kettle 9. The dropping feeding pipe is inserted into the bottom water (i.e., the deionized water required by the formula) in the reaction kettle 9 to prevent a large amount of volatile gases from being generated when directly entering the reaction kettle in the existing process without contacting the liquid level, and to prevent the self-polymerization reaction from occurring during the process of the second discharge flowing down along the kettle wall or splashing during dropping under the condition that the oxidant volatilizes above 25°C, and to prevent the formation of acrylic acid self-polymers, self-polymer gel substances of acrylic acid and hydroxyethyl acrylate along the kettle wall or the stirring shaft. This self-polymer gel substance will destroy the acid-ether ratio in the water reducer, reduce the reaction yield, and prevent the need for frequent manual entry into the reaction kettle 9 to clean the gel, which is time-consuming, laborious, and unsafe, and will also generate solid waste. To prevent the dropping feeding pipe of the reaction kettle 9 from colliding with the stirrer or the liquid rotation causing the feeding pipe to shake violently and be damaged, the dropping feeding pipe should be as close as possible to the kettle wall and fixed on the kettle wall.

[0049] A feeding manhole and a reflux pipe orifice are arranged on the reaction kettle 9. The manhole and the reflux pipe orifice are arranged opposite to each other. A wire mesh trap 11 is installed below the reflux pipe orifice. See Figure 2In (a), (b), and (c), the wire mesh collector 11 includes a cylinder body 23. A flange 24 is provided at the top of the cylinder body 23, and a number of filter holes 25 are formed in the side wall of the cylinder body 23. A reflux condenser 10 is installed on the upper pipe orifice of the wire mesh collector 11 through connecting bolts 26, and the tail gas pipeline 19 is connected through a valve at the gas outlet of the reflux condenser 10. The size of the upper pipe orifice of the wire mesh collector 11 is preferably 150 mm - 200 mm to facilitate the butt joint installation of the wire mesh collector 11 and the reflux condenser 10. During production, the tail gas valve is opened, and by using the negative pressure of the tail gas pipeline 19, the air flow near the manhole is sucked into the reaction kettle 9. When the manhole is opened during production, the dust generated when the solid macromonomer (hydroxyl-terminated polyoxyethylene ether) poured into the reaction kettle 9 falls will not overflow outside the manhole. These dusts are collected by the wire mesh when passing through the wire mesh collector 11 under negative pressure, preventing dust pollution and increasing the yield of the macromonomer. As the reaction proceeds and the temperature rises, part of the volatilized water vapor and volatile reaction raw materials are condensed and refluxed by the reflux condenser 10. The macromonomer dust attached to the wire mesh collector 11 is brought into the reaction kettle 9 by the condensed water and can continue to participate in the reaction. After the reaction is completed, the water to be supplemented according to the solid content set by the water reducer formula is added through the water inlet at the top of the reflux condenser 10, which can clean the reflux condenser 10 and the wire mesh collector 11.

[0050] The wire mesh collector 11 described above can be in various forms, and the best materials are polypropylene plastic or stainless steel. For easy cleaning and maintenance, the upper part of the wire mesh collector 11 is a flange with the same size as the reflux port of the reaction kettle 9. The flange opening is one specification smaller than the reflux port of the reaction kettle 9 to facilitate the insertion of the lower hanging basket (cylinder wall) into the reaction kettle 9. The side and bottom of the hanging basket welded to the lower part of the flange should be perforated or have long slits, and the size should be such that the packing will not fall off. The area of the perforations or slits should be more than 3 times the area of the pipe orifice to ensure smooth ventilation of the tail gas. The diameter of the hanging basket is preferably 150 mm - 200 mm (matched with the reflux port of the reaction kettle 9). For a hanging basket with a diameter of 150 mm, the height should not be less than 600 mm, and for a hanging basket with a diameter of 200 mm, the height should not be less than 450 mm. The inside of the hanging basket is filled with stainless steel wire mesh with a mesh size smaller than 100 meshes, or randomly filled with packings such as ceramics, plastic Pall rings, Raschig rings, corrugated packings, or ladder rings.

[0051] The form of the reflux condenser 10 can be a vertical tube condenser, a double-pipe condenser, a coil condenser, a spiral plate condenser, etc. The vertical tube condenser with the condensed medium flowing through the tube side has the best effect, and the heat transfer area should not be less than 10 m 2。The calcium chloride solution of the refrigerant in the brine tank 13 enters the reflux condenser 10 through the coolant circulation pump 12 and then returns to the brine tank for circulation, so that the volatile substances and water vapor in the tube side of the reflux condenser 10 are condensed and then refluxed into the reaction kettle 9, which can improve the yield of the reactants and reduce the environmental pollution of volatile organic compounds at the same time. The temperature of the circulating brine in the brine tank 13 is preferably controlled between 0°C and 10°C. When the brine temperature is below 0°C, the reflux liquid will freeze and affect the effect. A refrigerator 14 is used to cool the brine in the brine tank 13. The evaporator of the refrigerator 14 is placed in the brine tank 13. The refrigerator 14 uses a non-fluorocarbon environmentally friendly refrigerant. It is better to select a unit with a refrigeration capacity of more than 50,000 kcal according to the volume and quantity of the reaction kettle 9. The refrigerator with the best refrigeration capacity can also be selected through thermodynamic calculation.

[0052] The tail gas absorption tower 16 can be made of plastic or stainless steel, and plastic is preferred. The tower body of the tail gas absorption tower 16 is located above the alkali tank 17 (tower kettle). The tower body is composed of 2 or 3 tower sections. The diameter of the tower section is preferably 300 mm - 500 mm, and the height of the tower body should be not less than 3 meters. The upper tower section is provided with an absorption alkali liquid spray pipe, and the lower tower section is provided with a sieve plate. A packing layer is arranged on the sieve plate. Plastic, stainless steel, ceramic Pall rings, ladder rings, Raschig rings or corrugated packing (corrugated packing is filled according to the specification) are randomly stacked on the sieve plate, and the height of the packing layer should be not less than 2 meters. An efficient demister should be installed above the spray pipe in the tail gas absorption tower 16 to prevent trace small liquid droplets from being entrained by the tail gas and escaping into the air. The absorption alkali liquid is stored in the alkali tank 17.

[0053] The tail gas pipeline 19 is connected to above the liquid level of the alkali in the alkali tank 17 through a centrifugal fan 15. The centrifugal fan 15 must have a high air volume and air pressure to overcome the pipeline resistance and packing resistance. The specific type selection of the fan should be based on the distance of the tail gas pipeline and the number of reaction kettles in the system.

[0054] During production, the alkali liquid is circulated through the alkali liquid circulation pump 18 to spray and absorb the acidic gas and trace dust in the tail gas, so that the discharged air meets the environmental protection requirements. After the reaction is completed, the discharge valve is opened to pump the alkali liquid into the reaction kettle 9 to neutralize the water reducer mother liquor, and the polycarboxylic acid superplasticizer is obtained to end the reaction.

[0055] If there are multiple reaction kettles 9, an independent liquid alkali high-level tank with metering (weight sensor) should be set on each reaction kettle. After the reaction is completed, the alkali liquid required for each reaction kettle is pumped into the high-level tank through the alkali liquid circulation pump respectively, and then the alkali liquid is added to the reaction kettle through their respective high-level tanks.

[0056] Preferably, electromagnetic valves and weight sensors are added to the device and other electric control facilities are supported at the same time to realize the automatic control of the process. If the automatic system is not used, it does not affect the implementation of the present invention.

[0057] A method for improving the synthesis reaction yield of polycarboxylate superplasticizer and preventing pollution based on the above device, comprising the following steps (taking the production of 10 tons of polycarboxylate superplasticizer per kettle as an example):

[0058] Step 1: Open the inlet valve of the alkali circulation pump 18, start the alkali circulation pump 18, close the valve between the outlet of the alkali circulation pump 18 and the reaction kettle 9, and open the valve between the alkali circulation pump 18 and the tail gas absorption tower 16 to make the alkali solution start to circulate in the tail gas absorption tower 16. Then start the centrifugal fan 15 to make the tail gas pipeline in a negative pressure state. Open the deionized water valve and add 510 Kg of deionized water specified in the product process formula for 10 tons of products to the alkali preparation tank 1. The control method can be to manually close the valve according to the water meter reading or control the closing of the electric control valve or pneumatic valve according to the value of the weight sensor. Open the tail gas valve of the alkali preparation tank 1 to make the alkali preparation tank 1 in a negative pressure state. At the same time, start the agitation of the alkali preparation tank 1, and pour 245 Kg of bagged caustic soda in the amount specified in the 10-ton product formula into the alkali preparation tank 1 through the manhole. Since the alkali preparation tank 1 is in a negative pressure state, the dust generated during the falling process when pouring into the tank and the air entering through the charging manhole are sucked into the tail gas absorption tower 16 by the centrifugal fan 15 through the tail gas pipeline 19 and absorbed, preventing the caustic soda dust from causing corrosive harm to workers and preventing the generation of dust waste gas. After the solid caustic soda is completely dissolved, close the agitation of the alkali preparation tank 1 and start the alkali solution pump 4 to pump the prepared alkali solution into the alkali tank 17. When the new equipment is put into use for the first time to prepare the neutralization alkali solution, it is necessary to prepare an alkali solution with a mass 20% more than the process formula. The purpose is that when the reaction is over and the alkali solution is pumped into the reaction kettle 9 to neutralize the superplasticizer mother liquor, 20% of the alkali solution can remain, so as to have a certain amount of alkali solution when starting the alkali solution circulation in the next production and ensure the normal operation of the tail gas absorption tower 16. When producing for the second time, the alkali solution can be prepared according to the formula dosage, so that a certain amount of alkali solution can always be maintained in the alkali tank 17, which is convenient for the next feeding.

[0059] Step 2: With the tail gas absorption tower 16 operating normally, open the tail gas valve of the first premixing tank 2 to make it in a negative pressure state, and start stirring the first premixing tank 2. Manually or automatically control to open the deionized water valve of the first premixing tank 2 and add 570 Kg of deionized water as specified in the product process formula for 10 tons. The control method can be to manually close the valve according to the water meter reading or control the closing of the electric control valve or pneumatic valve according to the value of the weight sensor. A first feed pipe 21 is provided on the first premixing tank 2. One end of the first feed pipe 21 is connected to the mercaptopropionic acid feed pump. Insert the suction pipe of the mercaptopropionic acid feed pump into the packaging barrel of the mercaptopropionic acid chain transfer agent, and pump 20 Kg of mercaptopropionic acid as specified in the product process formula for 10 tons into the first premixing tank 2 through the first feed pipe 21. This first feed pipe 21 is inserted below the liquid level of the prepared water required by the formula. After the chain transfer agent enters the water, it is quickly diluted, reducing volatility. The remaining small amount of volatile gas is sucked into the tail gas pipeline 19 and enters the tail gas absorption tower 16 to be absorbed by the excessive fresh lye, preventing the harm of harmful waste gas to workers and the environment. When the amount of the chain transfer agent reaches the formula dosage, the weight sensor automatically closes the mercaptopropionic acid feed pump through the program (it can also be manually closed). Open the manhole and pour 9 Kg of the reducing agent VC, which is the dosage specified in the 10-ton product formula, into the first premixing tank 2. Since the first premixing tank 2 is in a negative pressure state, the dust generated during the fall when pouring into the first premixing tank 2 and the air entering through the manhole are sucked into the tail gas absorption tower 16 by the centrifugal fan through the tail gas pipeline 19 and absorbed, preventing the corrosive harm of the dust to workers and the generation of dust waste gas. Open the tail gas pipeline valve of the second high-level tank 8 to make it communicate with the tail gas absorption pipeline 19. Close the stirring of the first premixing tank 2 and start the discharge pump 5 of the first premixing tank 1 to pump the prepared first discharge into the second high-level tank 8 for standby.

[0060] Step 3: With the tail gas absorption tower 16 operating normally, open the tail gas valve of the second premixing tank 3 to put it in a negative pressure state, and start the agitation of the second premixing tank 3. Manually or automatically control the opening of the deionized water valve of the second premixing tank 3 to add 300 Kg of water as specified in the 10-ton process recipe. The control method can be to manually close the valve according to the water meter reading or to close the valve through a computer program using an electric control valve or a pneumatic valve based on the value of the weight sensor. A second feed pipe 22 is provided on the second premixing tank 3. One end of the second feed pipe 22 is connected to an acrylic feed pump. Insert the suction pipe of the acrylic feed pump into the packaging barrel of acrylic monomer, and pump 490 Kg of acrylic acid as specified in the 10-ton product process recipe into the second premixing tank 3 through the feed pipe 22. This second feed pipe 22 is inserted below the liquid level of the formulated water required by the recipe. After the acrylic acid and other reactive monomers enter the water, they are quickly diluted, reducing volatility. The remaining small amount of volatile gas is sucked into the tail gas pipeline 19 and enters the tail gas absorption tower to be absorbed by the excessive fresh lye, preventing the harm of harmful waste gas to workers and the environment. When the acrylic acid and other reactive monomers reach the recipe dosage, the weight sensor automatically closes the acrylic feed pump through the program, or it can also be manually closed. Stop the agitation of the second premixing tank 3, open the tail gas pipeline valve of the first high-level tank 7 to connect it to the tail gas absorption pipeline 19, and start the discharge pump 6 of the second premixing tank to pump the formulated second discharge into the first high-level tank 7 for standby.

[0061] Step 4: Start the refrigerator 14 30 minutes before feeding, and then start the coolant circulation pump 12 to make the refrigerated brine enter the brine tank 13 through the shell side of the reflux condenser for circulation. Before feeding, it should be ensured that the brine temperature is greater than 0°C and less than or equal to 10°C. Open the valve of the tail gas pipeline of the reflux condenser to connect it to the absorption tower through the tail gas pipeline 19. Manually or automatically control to open the deionized water valve, and add 2800 Kg of bottom water specified in the product process formula for 10 tons of products to the reaction kettle 9 through the tube side channel of the reflux condenser. The control method can be to manually close the valve according to the water meter reading or use an electric control valve or a pneumatic valve to close the valve through a computer program according to the value of the weight sensor. Start the agitation of the reaction kettle 9, open the manhole, and pour 3500 Kg of the macromonomer (methyl allyl polyoxyethylene ether) measured according to the 10-ton product formula into the reaction kettle 9. The generated dust is adsorbed by the wire mesh trap 11 through negative pressure, and a small amount of dust enters the tail gas absorption tower 16 through the tail gas pipeline 19 and is absorbed by the liquid caustic soda, preventing the dust gas from harming the environment and the health of the operators. Add 23 Kg of hydrogen peroxide oxidant specified in the 10-ton product formula through the manhole, close the manhole, and start stirring for 5 - 10 minutes. Then start dropping the small monomer (second discharge) and the chain transfer agent (first discharge) simultaneously. The dropping time is 3 hours. It should be ensured that the two dropping liquids are dropped simultaneously or the second discharge is dropped about 10 minutes faster than the first dropping liquid. Generally, the dropping rate is controlled by controlling the opening of the valve through the weight sensor during the dropping process. The volatile gases and water vapor generated during the dropping process are condensed and refluxed to the reaction kettle when passing through the reflux condenser, and the remaining small amount of acidic volatile substances enter the absorption tower through the tail gas pipeline 19 and are absorbed by the fresh caustic soda solution, preventing the pollution of harmful gases to the environment and the harm to the operators. After the dropping is completed, keep the temperature for 1 hour according to the process requirements. Open the deionized water valve, and add 1550 Kg of the remaining deionized water specified in the 10-ton product formula through the reflux condenser and the wire mesh trap to adjust the solid content of the mother liquor to 40%. This process also has the purpose of cleaning the reflux condenser and the wire mesh trap. Open the valve from the alkali circulation pump 18 to the reaction kettle 9, and automatically add 755 Kg of the alkali solution prepared in Step 1 to the reaction kettle 9 according to the data of the weight sensor for neutralization reaction. Continue stirring for about 5 - 10 minutes, then turn off the stirring, turn off the centrifugal fan 15, turn off the alkali circulation pump 18, turn off the refrigerator 14, and turn off the coolant circulation pump 12. After sampling and testing are qualified, a production cycle of the water reducing agent is completed.

[0062] According to the comparative production test, there is no significant difference in the performance of the polycarboxylic acid superplasticizer produced by the method of the present invention and the polycarboxylic acid superplasticizer produced by the existing method.

[0063] Due to a series of improvements and combinations of pipelines and equipment in the present invention, various raw materials in the synthesis process of water reducing agents are fully utilized, losses are reduced, and the yield in the reaction process is increased, which is manifested as an increase in the solid content of the reaction product. The solid content of the polycarboxylate superplasticizer produced by the method of the present invention is increased by 0.5%-1% compared with that of the polycarboxylate superplasticizer produced by the existing process method.

[0064] Due to the use of fresh lye with a high concentration and greatly in excess of the relative tail gas components for tail gas absorption, the outlet gas of the tail gas absorption tower 16 of the present invention is detected by a third-party testing agency, and no acrylic gas and macromonomer (allyl polyoxyethylene ether) components are detected in the tail gas.

[0065] After the high-performance polycarboxylate water reducing agent is produced by the present invention, no solid gel-like acrylic self-polymerized substances are found on the reaction kettle wall and the stirrer, and the problem of solid hazardous waste is solved.

[0066] For the product obtained by feeding materials according to the formula with a theoretical solid content of 40% in the prior art, the actually measured solid content of the reactants is generally 37-38%, and the reactant yield is 92.5%-95%. For the water reducing agent product with the same formula produced according to Steps 1 to 4 of the present invention, the actually measured solid content is 38.5%-39%, and the reaction yield is 96.25%-97.5%. It can be seen that the present invention can not only improve economic benefits, but also achieve the purpose of environmental protection.

[0067] The method of the present invention is applicable to the process production of polycarboxylate superplasticizer series products such as water reducing agents, slump retaining agents, water reducing and slump retaining agents, anti-sludge water reducing agents, and anti-sludge slump retaining agents produced with C4, C5, and C6 carbon chains as macromonomers.

Claims

1. Device for improving the yield of polycarboxylate superplasticizer and preventing pollution, Characterized in that, It includes an alkali preparation tank (1), a first premixing tank (2), a second premixing tank (3), a reaction kettle (9), a reflux condenser (10), a wire mesh trap (11), a brine tank (13), an absorption tower (16), an alkali tank (17) and a tail gas pipeline (19); Among them, the alkali preparation tank (1) is connected to the alkali tank (17), the first premixing tank (2) and the second premixing tank (3) are connected to the reaction kettle (9), a reflux condenser (10) is arranged at the top of the reaction kettle (9), a wire mesh trap (11) is arranged at the bottom of the reflux condenser (10), a brine inlet and a brine outlet are arranged on the reflux condenser (10), the outlet of the brine tank (13) is connected to the brine inlet, and the brine outlet is connected to the inlet of the brine tank (13); an alkali tank (17) is arranged at the bottom of the absorption tower (16), the alkali tank (17) is connected to the reaction kettle (9), and the alkali preparation tank (1), the first premixing tank (2), the second premixing tank (3), the alkali tank (17) and the reflux condenser (10) are connected to the tail gas pipeline (19).

2. The device for improving the yield of polycarboxylate superplasticizer and preventing pollution according to claim 1, Characterized in that, A caustic soda inlet (20), a deionized water inlet and a tail gas outlet are arranged at the top of the alkali preparation tank (1), an outlet is arranged at the bottom of the alkali preparation tank (1), a first feed pipe (21), a deionized water inlet and a tail gas outlet are arranged at the top of the first premixing tank (2), a second feed pipe (22), a deionized water inlet and a tail gas outlet are arranged at the top of the second premixing tank (3), and outlets are arranged at the bottoms of the first premixing tank (2) and the second premixing tank (3); the first feed pipe (21) extends into the bottom of the first premixing tank (2), and the second feed pipe (22) extends into the bottom of the second premixing tank (3).

3. The device for improving the yield of polycarboxylate superplasticizer and preventing pollution according to claim 1, Characterized in that, The first premixing tank (2) is connected to the reaction kettle (9) through a first discharge pump (5) and a second high-level tank (8); the second premixing tank (3) is connected to the reaction kettle (9) through a second discharge pump (6) and a first high-level tank (7).

4. The device for improving the yield of polycarboxylate superplasticizer and preventing pollution according to claim 3, Characterized in that, A reflux port is arranged at the top of the reaction kettle (9), the wire mesh trap (11) is arranged below the reflux port, the reflux condenser (10) is arranged above the reflux port, and a deionized water inlet is opened at the upper part of the reflux condenser (10); Emptying pipelines connected to the tail gas pipeline (19) are arranged at the tops of the alkali preparation tank (1), the first premixing tank (2), the second premixing tank (3), the first high-level tank (7) and the second high-level tank (8) and the reflux condenser (10).

5. The device for improving the yield of polycarboxylate superplasticizer and preventing pollution according to claim 1, Characterized in that, The tail gas pipeline (19) is connected to the alkali tank (17) through a centrifugal fan (15); the alkali tank (17) is connected to the reaction kettle (9) through an alkali liquor circulation pump (18).

6. The device for improving the yield of polycarboxylate superplasticizer and preventing pollution according to claim 1, characterized in that, the brine tank (13) is further connected with a refrigerator (14).

7. The device for improving the yield of polycarboxylate superplasticizer and preventing pollution according to claim 1, characterized in that, a first raw material adding pipe is arranged on the first premixing tank (2), and the first raw material adding pipe is inserted into the deionized water liquid level in the first premixing tank (2) through a head; a second raw material adding pipe is arranged on the second premixing tank (3), and the second raw material adding pipe is inserted into the deionized water liquid level in the second premixing tank (3) through a head; a dropping feed pipe is arranged on the reaction kettle (9), and the dropping feed pipe is inserted into the bottom water liquid level in the reaction kettle (9); the reflux condenser (10) is connected with the wire mesh trap (11), and the reflux condenser (10) is installed in a vertical or horizontal installation manner.

8. The device for improving the yield of polycarboxylate superplasticizer and preventing pollution according to claim 3, characterized in that, the alkali preparation tank (1) is connected with the alkali tank (17) through an alkali liquid pump (4); weight sensors are arranged at the bottoms of the alkali preparation tank (1), the first premixing tank (2), the second premixing tank (3), the first high-level tank (7), the second high-level tank (8) and the alkali tank (17).

9. The device for improving the yield of polycarboxylate superplasticizer and preventing pollution according to claim 1, characterized in that, the wire mesh trap (11) is a trap filled with wire mesh packing, ceramic or plastic packing rings inside.

10. A method for improving the yield of polycarboxylate superplasticizer and preventing pollution based on the device according to claim 1, characterized in that, comprises the following steps: Step 1, turn on the fan (15) to make the tail gas pipeline (19) in a negative pressure state, add deionized water into the alkali preparation tank (1), and make the alkali preparation tank (1) in a negative pressure state, add flake alkali into the alkali preparation tank (1), stir and dissolve it, and then pump it into the alkali tank (17); Step 2, make the first premixing tank (2) in a negative pressure state, add deionized water into the first premixing tank (2), add a reducing agent and a chain transfer agent into the first premixing tank (2), stir evenly, and obtain the first discharge; Step 3, make the second premixing tank (3) in a negative pressure state, start the stirring of the second premixing tank (3), open the deionized water valve of the second premixing tank (3), add acrylic acid or hydroxyethyl acrylate into the second premixing tank (3), stir evenly, and obtain the second discharge; Step 4, add bottom water into the reaction kettle (9) through the tail gas process channel of the reflux condenser, make the reaction kettle (9) in a negative pressure state, start the stirring of the reaction kettle (9), add methallyl polyoxyethylene ether into the reaction kettle (9), stir evenly, add an oxidizing agent, stir evenly, drop the first discharge and the second discharge, then keep warm, add deionized water through the reflux condenser (10) and the wire mesh trap (11), adjust the solid content, add an alkali solution for neutralization reaction, and obtain the superplasticizer.

Images