Ethyl maltol neutralization reaction system and method

Abstract

The invention belongs to the technical field of neutralization reaction equipment, and particularly relates to an ethyl maltol neutralization reaction system and method. The system comprises a neutralization kettle, a liquid alkali tank, a neutralization circulating pump, a circulating liquid inlet and a feed port, the feed port is formed in the top of the neutralization kettle, and hydrolysate is added into the neutralization kettle through the feed port; the kettle body of the neutralization kettle is provided with a circulating liquid inlet, and the circulating liquid inlet is lower than the liquid level of the neutralization kettle; a discharge hole is formed in the bottom of the neutralization kettle and is connected with a circulating liquid inlet through a neutralization circulating pump; the liquid caustic soda tank is connected with an inlet of the neutralization circulating pump. The invention avoids direct contact between the liquid caustic soda and the enamel kettle wall of the neutralization kettle, reduces the equipment loss, prolongs the service life of the neutralization kettle and the stirring shaft, prolongs the service life of the equipment, and saves the cost.

Description

Technical Field

[0001] This invention belongs to the field of ethyl maltol production technology, specifically relating to an ethyl maltol neutralization reaction system and method. Background Technology

[0002] The existing process for producing ethyl maltol is a synthetic process using furfural as a raw material. First, Grignard reagents are prepared by reacting ethane chloride and magnesium in the presence of toluene and tetrahydrofuran solvents. Then, furfural is added, followed by hydrolysis to obtain furfuryl alcohol intermediate. The obtained furfuryl alcohol is then chlorinated with chlorine gas in methanol and water solvents. After the reaction is completed, it is heated to carry out a hydrolysis reaction to obtain a hydrolysate containing hydrochloric acid. Finally, the pH value of the hydrolysate is adjusted with liquid alkali to generate crude ethyl maltol, which is then sublimated and crystallized to obtain the final product.

[0003] The production of ethyl maltol employs a traditional neutralization reaction process, where liquid alkali is added dropwise from the top of the neutralization vessel, and neutralization is completed by manually adjusting the pH value. The specific process includes: 1. Liquid alkali is added directly to the surface of the liquid in the vessel; 2. The mixture is stirred using a single-layer paddle agitator; 3. The pH value is monitored manually and the liquid alkali flow rate is adjusted.

[0004] Disadvantages and shortcomings of traditional neutralization reaction processes: 1. Severe equipment corrosion: The liquid alkali is added on the surface of the liquid, causing direct contact between the alkali solution and the enamel-lined reactor wall, which can easily lead to the agitator shaft and reactor wall cracking, affecting product quality and resulting in high maintenance costs; 2. Low reaction efficiency: Uneven distribution of liquid alkali and reliance on manual operation for pH adjustment can easily lead to adjustment deviations, resulting in a decrease in the yield of ethyl maltol; 3. Safety hazards: Frequent manual operation poses safety risks such as alkali leakage and equipment corrosion; it also restricts the efficiency of subsequent processes and limits capacity expansion. Summary of the Invention

[0005] To address the technical problem of severe equipment corrosion in the traditional neutralization reaction of ethyl maltol production—where liquid alkali is added at the liquid surface, causing direct contact between the alkali solution and the enamel-lined reactor wall, which easily leads to enamel cracking of the stirring shaft and reactor wall, affecting product quality and resulting in high maintenance costs—this invention provides the following technical solution: Firstly, This invention provides an ethyl maltol neutralization reaction system, including a neutralization vessel, a liquid alkali tank, a neutralization circulation pump, a circulation liquid inlet, and a feed inlet. The feed inlet is provided at the top of the neutralization vessel, through which hydrolysate is added to the neutralization vessel. The neutralization vessel is equipped with a circulating liquid inlet, the height of which is lower than the liquid level in the neutralization vessel. The neutralization vessel is equipped with a discharge port at the bottom, which is connected to the inlet of the circulating liquid via a neutralization circulation pump. The liquid alkali tank is connected to the inlet of the neutralization circulation pump.

[0006] Furthermore, the neutralization vessel is equipped with a double-layer propulsion agitator, which includes a stirring shaft and two layers of blades mounted on the stirring shaft, namely an upper blade and a lower blade.

[0007] Furthermore, the dual-layer propeller mixer rotates at a speed of 60 rpm.

[0008] Furthermore, the lower blades cause the material in the neutralization vessel to tumble upwards, while the upper blades cause the material in the neutralization vessel to press downwards.

[0009] Furthermore, the lower blades adopt flat-bladed disc turbine blades, while the upper blades adopt three-bladed propeller blades.

[0010] Furthermore, a regulating valve and a flow meter are connected in series between the liquid alkali tank and the inlet of the neutralization circulation pump.

[0011] Furthermore, an online pH meter is installed between the neutralization circulation pump and the circulation liquid inlet.

[0012] Furthermore, it also includes a DCS control system, which is linked with the online pH meter and regulating valve.

[0013] Furthermore, a static mixer is installed at the inlet of the neutralization circulation pump.

[0014] Secondly, This invention provides a process for neutralizing ethyl maltol, comprising: The hydrolysate containing hydrochloric acid after the hydrolysis reaction during the production of ethyl maltol is added to the neutralization vessel through the top feed inlet, and the double-layer propeller agitator of the neutralization vessel is turned on at the same time for stirring. Start the neutralization circulation pump to send the hydrolysate from the bottom of the neutralization vessel to the circulation inlet and into the neutralization vessel, where the hydrolysate circulates. Open the regulating valve, and the liquid alkali in the liquid alkali tank will participate in the circulation process of the hydrolysate through the neutralization circulation pump. The liquid alkali will be added to the hydrolysate through the circulation process of the hydrolysate in the neutralization vessel, and will be fully mixed with the circulating hydrolysate to carry out the neutralization reaction and form a neutralized liquid. The online pH meter detects the pH value of the neutralizing solution in real time and transmits it to the DCS control system in real time. After the neutralizing solution is circulated by the neutralization circulation pump for 1 minute, the DCS control system controls the opening of the regulating valve and then adjusts the amount of liquid alkali added to automatically control the opening of the regulating valve to achieve the pH value. Once the pH value stabilizes in the range of 2.5 to 3.5, the neutralization reaction is completed.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention modifies the liquid alkali dripping pipeline to the inlet of the circulating pump, improving the liquid alkali addition method. Compared with liquid alkali dripping from the top of the neutralization vessel, the liquid alkali addition method of this invention achieves uniform mixing through circulation mixing, avoiding direct contact between liquid alkali and the enamel wall of the neutralization vessel, reducing equipment wear, extending the service life of the neutralization vessel and the stirring shaft, improving the service life of the equipment, and saving costs.

[0016] This invention optimizes the circulation path of the neutralization vessel circulating liquid. The circulating liquid inlet of the neutralization vessel is moved to the vessel body, ensuring that the height of the circulating liquid inlet is always below the liquid level in the neutralization vessel. This ensures that the added liquid alkali is always submerged below the liquid level in the neutralization vessel. Compared with the liquid alkali being added drop by drop from the top of the neutralization vessel, this invention can avoid the liquid alkali directly contacting the enamel, preventing localized corrosion and improving the service life of the equipment.

[0017] This invention employs a double-layer propulsion agitator, where the lower layer of blades tumbles the material upwards, while the upper layer of blades presses the material downwards, thereby improving the uniformity of mixing of the liquid in the neutralization vessel.

[0018] The ethyl maltol neutralization reaction system of the present invention can achieve continuous and automated operation, avoid excessive human involvement in the production process, reduce human error, save manpower, and improve the safety of the equipment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the ethyl maltol neutralization reaction system of the present invention.

[0020] Figure label: 1-Neutralization vessel, 2-Liquid alkali tank, 3-Vent pipe, 4-Regulating valve, 5-Flow meter, 6-Neutralization circulation pump, 7-Online pH meter, 8-Circulating liquid inlet, 9-Feed inlet, 10-Agitator shaft; 111-Upper impeller, 112-Lower impeller. Detailed Implementation

[0021] The technical solution of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0022] Example 1 like Figure 1 As shown, the present invention provides an ethyl maltol neutralization reaction system, including a neutralization vessel 1, a liquid alkali tank 2, a vent pipe 3, a regulating valve 4, a flow meter 5, a neutralization circulation pump 6, an online pH meter 7, a circulating liquid inlet 8, a feed inlet 9, and a DCS control system or a PLC system.

[0023] The neutralization vessel 1 is equipped with a feed inlet 9 and a vent pipe 3 at the top. Hydrolysate containing hydrochloric acid, which is produced during the hydrolysis reaction of ethyl maltol, is added to the neutralization vessel 1 through the feed inlet 9. The hydrolysate mainly contains ethyl maltol (the main component), hydrochloric acid, methanol, and water. The hydrolysate is used as a recycled material. Liquid alkali is added to the hydrolysate to carry out a neutralization reaction.

[0024] A circulating liquid inlet 8 is provided at the body of the neutralization vessel 1, and the height of the circulating liquid inlet 8 is lower than the liquid level of the neutralization vessel 1.

[0025] A discharge port is provided at the bottom of the neutralization vessel 1. The discharge port at the bottom of the neutralization vessel 1 is connected to the circulating liquid inlet 8 via the neutralization circulation pump 6. Through the neutralization circulation pump 6, the hydrolysate can circulate from the bottom of the neutralization vessel 1 → neutralization circulation pump 6 → circulating liquid inlet 8.

[0026] In another embodiment, a static mixer may also be added at the inlet of the neutralization circulation pump 6.

[0027] The neutralization vessel 1 is equipped with a double-layer propeller agitator, which operates at a speed of 60 rpm. The double-layer propeller agitator includes a stirring shaft 10 and two layers of blades set on the stirring shaft 10. The two layers of blades are an upper blade 111 and a lower blade 112. The lower blade 112 causes the material at the bottom of the neutralization vessel 1 to turn upward, while the upper blade 111 causes the material in the upper layer to press downward.

[0028] The lower blade 112 adopts a flat-bladed disc turbine blade. When it is running, the material generates a radial liquid flow, which pushes the bottom material upward to form an "upward flipping" effect.

[0029] The upper blade 111 adopts a three-bladed propeller blade. When it is running, the material generates an axial liquid flow, which pushes the upper material downward to form a "downward pressure" effect.

[0030] After the double-layer propeller agitator is started, the two layers of blades rotate simultaneously. The material is overturned under the action of the lower blade 112, and the material is under downward pressure under the action of the upper blade 111. The two flow modes converge in the middle of the neutralization vessel 1 to form a convection circulation. The double-layer propeller agitator (lower layer overturns, upper layer presses down) can better improve the mixing uniformity of the liquid undergoing the neutralization reaction in the neutralization vessel 1.

[0031] Liquid alkali tank 2 is used to hold 32% liquid alkali.

[0032] The liquid alkali tank 2 is connected to the inlet of the neutralization circulation pump 6, and a regulating valve 4 and a flow meter 5 are connected in series between the liquid alkali tank 2 and the inlet of the neutralization circulation pump 6. When the regulating valve 4 is opened, the liquid alkali flows to the inlet of the neutralization circulation pump 6 by gravity, so that the liquid alkali is pre-mixed with the hydrolysate at the inlet of the circulation pump 6 and then added to the hydrolysate. Through circulation mixing, the liquid alkali is prevented from directly contacting the enamel wall of the neutralization vessel 1, reducing the degree of equipment corrosion and achieving better uniform mixing.

[0033] By circulating the hydrolysate in the neutralization vessel 1 through the circulation pump 6, liquid alkali is added to the hydrolysate to carry out a neutralization reaction and form a neutralized solution.

[0034] Because the circulating liquid inlet 8 is located in the vessel body, its height is lower than the liquid level of the neutralization vessel 1. This ensures that the added liquid alkali is always submerged below the liquid level of the neutralization vessel 1. The circular arrows inside the neutralization vessel 1 represent the direction of the neutralization liquid flow.

[0035] The position of the circulating liquid inlet 8 was optimized. The circulating liquid inlet 8 of the neutralization vessel 1 was moved to the vessel body to ensure that the circulating liquid inlet 8 is always below the liquid surface of the neutralization vessel 1, so as to avoid direct contact between the liquid alkali and the enamel vessel wall of the neutralization vessel 1 and prevent local corrosion.

[0036] The materials in the neutralization vessel 1 are thoroughly mixed by stirring with a double-layer propeller agitator.

[0037] An online pH meter 7 is installed between the outlet of the neutralization circulation pump 6 and the inlet of the circulating liquid 8. The DCS control system is linked with the online pH meter 7 and the regulating valve 4. Based on the pH value of the circulating liquid detected by the online pH meter 7, the DCS control system feeds back to control the opening of the regulating valve 4, adjusts the flow rate of the liquid alkali, and thus adjusts the pH value of the neutralization liquid. This allows the pH value of the online pH meter 7 to be controlled by the DCS system. The DCS system, combined with the online pH meter, achieves automatic pH adjustment, realizing automated pH control of the materials in the neutralization vessel 1.

[0038] After the neutralizing solution is circulated by the neutralization circulation pump 6 for 1 minute, the DCS control system adjusts the amount of liquid alkali added. Once the pH value stabilizes in the range of 2.5 to 3.5 (the optimal pH value is 3.0), the neutralization reaction is complete.

[0039] In this embodiment, 1300L of liquid alkali was added.

[0040] Work process: 1. Before starting the ethyl maltol neutralization reaction system, check the sealing of all connecting pipes; 2. Add the hydrolysate into the neutralization vessel 1 through the top feed port 9, and simultaneously stir the hydrolysate using a double-layer propeller agitator running at 60 rpm. 3. Start the neutralization circulation pump 6. The hydrolysate will circulate from the bottom of the neutralization vessel 1 to the neutralization circulation pump 6 and then to the circulation inlet 8. 4. The DCS control system automatically controls the opening of the regulating valve 4 based on the feedback from the online pH meter 7, and adjusts the amount of liquid alkali added to the liquid alkali tank 2. The liquid alkali is mixed with the circulating liquid before entering the neutralization tank 1, and then undergoes a neutralization reaction under the stirring of the double-layer propeller stirrer to form a neutralized liquid. 5. After the neutralization solution is circulated by the neutralization circulation pump 6 for 1 minute, the pH value stabilizes in the range of 2.5 to 3.5 (the optimal pH value is 3.0), completing the neutralization reaction and generating crude ethyl maltol, which is then sent to the sublimation section for sublimation and crystallization to obtain the finished product.

[0041] Example 2 like Figure 1 As shown, the present invention provides a process for neutralizing ethyl maltol, comprising: The hydrolysate containing hydrochloric acid after the hydrolysis reaction during the production of ethyl maltol is added to neutralizing vessel 1 through the top feed port 9, and the double-layer propeller agitator of neutralizing vessel 1 is turned on at the same time for stirring. Start the neutralization circulation pump 6 to send the hydrolysate from the bottom of the neutralization vessel 1 to the circulation inlet 8 and into the neutralization vessel 1, where the hydrolysate circulates. Open the regulating valve 4, and the liquid alkali in the liquid alkali tank 2 will participate in the hydrolysate circulation process through the neutralization circulation pump 6. The liquid alkali will be added to the hydrolysate through the circulation process of the hydrolysate in the neutralization vessel 1, and will be fully stirred and mixed with the hydrolysate in the neutralization vessel 1 to carry out the neutralization reaction and form a neutralized liquid. The online pH meter 7 can detect the pH value of the neutralization solution in real time and transmit it to the DCS control system in real time. After the neutralizing solution circulates for 1 minute, the DCS control system adjusts the opening of regulating valve 4 and the amount of liquid alkali added to achieve the pH value. Once the pH value stabilizes within the range of 2.5 to 3.5 (the optimal pH value is 3.0), the neutralization reaction is completed, producing crude ethyl maltol, which is then sent to the sublimation section for sublimation and crystallization to obtain the final product.

[0042] The dual-layer propeller mixer operates at 60 rpm to optimize material mixing.

[0043] The above technical features constitute the preferred embodiment of the present invention, which has strong adaptability and optimal implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the needs of different situations.

[0044] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. An ethyl maltol neutralization reaction system, comprising a neutralization vessel, a liquid alkali tank, a neutralization circulation pump, a circulation liquid inlet, and a feed inlet, characterized in that, The neutralization vessel is equipped with a feed inlet at the top, through which hydrolysate is added to the neutralization vessel; The neutralization vessel is equipped with a circulating liquid inlet, the height of which is lower than the liquid level in the neutralization vessel. The neutralization vessel is equipped with a discharge port at the bottom, which is connected to the inlet of the circulating liquid via a neutralization circulation pump. The liquid alkali tank is connected to the inlet of the neutralization circulation pump.

2. The ethyl maltol neutralization reaction system according to claim 1, characterized in that, The neutralization vessel is equipped with a double-layer propulsion agitator, which includes a stirring shaft and two layers of blades mounted on the stirring shaft, namely an upper blade and a lower blade.

3. The ethyl maltol neutralization reaction system according to claim 2, characterized in that, The dual-layer propeller mixer rotates at 60 rpm.

4. The ethyl maltol neutralization reaction system according to claim 2, characterized in that, The lower blades cause the material in the neutralization vessel to tumble upwards, while the upper blades cause the material in the neutralization vessel to press downwards.

5. The ethyl maltol neutralization reaction system according to claim 4, characterized in that, The lower blades are flat-bladed disc turbine blades, while the upper blades are three-bladed propeller blades.

6. The ethyl maltol neutralization reaction system according to any one of claims 1-5, characterized in that, A regulating valve and a flow meter are connected in series between the liquid alkali tank and the inlet of the neutralization circulation pump.

7. The ethyl maltol neutralization reaction system according to claim 6, characterized in that, An online pH meter is installed between the neutralization circulation pump and the circulation liquid inlet.

8. The ethyl maltol neutralization reaction system according to claim 7, characterized in that, It also includes a DCS control system, which is linked with the online pH meter and regulating valve.

9. An ethyl maltol neutralization reaction system according to any one of claims 1-5, characterized in that, A static mixer is installed at the inlet of the neutralization circulation pump.

10. A process for neutralizing ethyl maltol, characterized in that, include: The hydrolysate containing hydrochloric acid after the hydrolysis reaction during the production of ethyl maltol is added to the neutralization vessel through the top feed inlet, and the double-layer propeller agitator of the neutralization vessel is turned on at the same time for stirring. Start the neutralization circulation pump to send the hydrolysate from the bottom of the neutralization vessel to the circulation inlet and into the neutralization vessel, where the hydrolysate circulates. Open the regulating valve, and the liquid alkali in the liquid alkali tank will participate in the circulation process of the hydrolysate through the neutralization circulation pump. The liquid alkali will be circulated into the hydrolysate through the circulation process of the hydrolysate in the neutralization vessel, and will be fully mixed with the hydrolysate to carry out the neutralization reaction and form a neutralized liquid. The online pH meter detects the pH value of the neutralized liquid at the outlet of the neutralization circulation pump in real time and transmits it to the DCS control system in real time. After the neutralizing solution is circulated by the neutralization circulation pump for 1 minute, the DCS control system controls the opening of the regulating valve and then adjusts the amount of liquid alkali added to automatically control the opening of the regulating valve to achieve the pH value. Once the pH value stabilizes in the range of 2.5 to 3.5, the neutralization reaction is completed.

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