Sorbic acid micro-droplet sedimentation condensation tower and sorbic acid production method

Abstract

The invention discloses a sorbic acid micro-droplet sedimentation condensation tower and a sorbic acid production method, and relates to the technical field of organic raw material condensation reaction, the sorbic acid micro-droplet sedimentation condensation tower comprises a condensation tower body with a hollow inner cavity, a first gas inlet / outlet is formed in the side wall of the top of the condensation tower body, and a second gas inlet / outlet is formed in the side wall of the bottom of the condensation tower body; a micro-droplet jetting device, a micro-droplet reaction area and a spiral-plate heat exchanger are sequentially arranged in an inner cavity of the condensation tower body from top to bottom, a liquid accumulation area is arranged at the bottom of the condensation tower body, and a liquid discharging opening is formed in the bottom of the liquid accumulation area. The micro-droplet spraying device is used for replacing a grating distributor, the micro-droplet reaction area is used for replacing a packing ring, the problem that the surface area of a liquid phase in the condensation tower is small is effectively solved, and the spiral plate heat exchanger is used for replacing a heat exchange disc, so that the problem that the heat exchange capacity of the condensation tower is insufficient is effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of organic raw material condensation reaction, in particular to a sorbic acid micro-droplet sedimentation condensation tower and a sorbic acid production method. Background Art

[0002] Sorbic acid preservatives are non-toxic, highly safe and have good preservative effects. They are internationally recognized as the best food preservatives. So far, there are more than ten process routes for the synthesis of sorbic acid, but not many of them are suitable for industrialization. Industrial production practice has proved that the most successful and economical process route is the "acetic acid cracking-ethylene ketone / crotonaldehyde polycondensation-polyester acidolysis crystallization" process route.

[0003] Among them, the "ethylene ketone / crotonaldehyde condensation" process is the key to ensuring product quality and process economy. At present, the industry adopts an intermittent condensation reaction system, which includes a condensation kettle, a condensation tower, a cooler and a condensation liquid circulation pump. First, the condensation liquid in the condensation kettle enters from the top of the condensation tower through a circulation pump, and is distributed to the packing layer through a liquid distribution plate, flows through the packing layer from top to bottom, spreads and disperses on the packing as a continuous liquid film, and contacts the ethylene ketone gas entering from the bottom of the condensation tower and flowing from bottom to top in reverse, a condensation reaction occurs, and heat is released. The reaction heat is removed through the heat exchange coil on the tower wall. After the condensation liquid reacts in the condensation tower, it enters the condensation kettle at the bottom of the tower, and circulates to the top of the tower again through a circulation pump. After multiple cycles of reaction, after reaching the reaction end point, the reaction is terminated and the material is discharged at one time. The tail gas escaping from the top of the condensation tower is absorbed by the tail gas absorption device and then discharged.

[0004] In industrial condensation reaction systems, condensation reaction is one of the most critical reactions. The condensation reaction is mainly completed in the condensation tower. The design and operating performance of the condensation tower are the key to the process. Therefore, it is of great significance to innovatively design and enhance the mass transfer and heat transfer of the condensation reaction in the condensation tower.

[0005] In the existing industrial condensation reaction system, the condensation tower is usually in the form of a multi-layer packed tower, and the packing is designed to be 5 layers; after the condensation liquid enters from the liquid inlet pipe above the tower top, it directly enters the liquid phase distribution plate, which is composed of multiple grids, and there is a 2mm gap between the grids. The condensation liquid is distributed downward through the gap into the first packing layer at the top, and flows through the packing layer from top to bottom, spreads and disperses on the packing as a continuous liquid film, and contacts with the ethylene ketone gas entering from the bottom of the condensation tower and flowing from bottom to top in reverse direction, condensation reaction occurs, and heat is released. The reaction heat is removed through the cooling coils arranged inside and outside the tower wall. The condensation liquid flowing through the first packing layer then flows out from below the first packing layer, and enters the second, third, fourth and fifth packing layers in sequence, and after condensation reaction with the ethylene ketone gas entering from the bottom of the tower, it flows into the condensation kettle at the bottom of the tower, and enters the tower again through the liquid inlet pipe above the tower top through the circulating pump to continue the reaction. The reaction tail gas flows out from the tower top outlet and enters the tail gas absorption system.

[0006] The condensation tower in the prior art solution has the following shortcomings:

[0007] (1) The condensation liquid at the top of the tower is distributed by a grid distributor, the thickness of the liquid film formed is too large, and the liquid surface area is too small;

[0008] (2) The packing is made of stainless steel ball rings, and the specific surface area of ​​the packing is about 219 to 280 m 2 / m 3 , so the surface area of ​​the liquid spread on the filler surface is still relatively small;

[0009] (3) The heat exchange capacity of the condensation tower is insufficient, relying only on the stainless steel heat exchange coils inside and outside the tower wall. The heat exchange area is limited and the heat exchange rate is lagging.

[0010] Therefore, how to provide a sorbic acid micro-droplet settling condensation tower and a sorbic acid production method to increase the gas-liquid mass transfer area in the condensation tower and the heat exchange rate of the condensation tower has become a difficult problem to be solved urgently by those skilled in the art. Summary of the invention

[0011] The purpose of the present invention is to provide a sorbic acid micro-droplet sedimentation condensation tower and a sorbic acid production method, so as to solve the problems of small liquid surface area and insufficient heat exchange capacity caused by the use of a grid distributor and a packing ring in the existing condensation tower.

[0012] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0013] The invention provides a sorbic acid micro-droplet sedimentation condensation tower, comprising a condensation tower body with a hollow inner cavity, a first air inlet and outlet being installed on the top side wall of the condensation tower body, a second air inlet and outlet being installed on the bottom side wall of the condensation tower body, a micro-droplet injection device, a micro-droplet reaction zone and a spiral plate heat exchanger being sequentially arranged in the inner cavity of the condensation tower body from top to bottom, a liquid accumulation zone being arranged at the bottom of the condensation tower body, and a liquid discharge port being arranged at the bottom of the liquid accumulation zone.

[0014] Preferably, the horizontal setting height of the first air inlet and outlet is higher than the horizontal setting height of the micro-droplet injection device.

[0015] Preferably, the micro-droplet injection device adopts a liquid phase atomization nozzle, and the liquid phase atomization nozzle includes a solid cone nozzle, a hollow cone nozzle and / or an impact pin atomization nozzle.

[0016] Preferably, the horizontal setting height of the spiral plate heat exchanger is higher than the horizontal setting height of the second air inlet and outlet.

[0017] Preferably, the liquid accumulation area is funnel-shaped, and the liquid discharge port is arranged at the bottom center of the liquid accumulation area.

[0018] Preferably, the spiral plate heat exchanger is made of heat exchange plates, and the heat exchange plates are provided with multiple layers and are evenly distributed along the radial direction of the condensation tower.

[0019] The present invention also provides a production method applied to the sorbic acid micro-droplet sedimentation condensation tower, comprising the following steps:

[0020] Step 1, spraying operation: spraying the condensation liquid raw material into the micro-droplet reaction zone according to a preset liquid phase flow rate through the micro-droplet injection device;

[0021] Step 2, ventilation operation: while performing the spraying operation, the ketene gas is introduced into the condensation tower through the first gas inlet and outlet or the second gas inlet and outlet at a preset flow rate to perform a parallel flow ventilation operation or a counter-flow ventilation operation;

[0022] When the parallel flow ventilation operation is performed, the ketene gas enters the condensation tower from the first gas inlet and outlet, passes through the micro-droplet reaction zone in the condensation tower and the gap in the spiral plate heat exchanger in sequence, and then leaves the condensation tower from the second gas inlet and outlet, and undergoes a condensation reaction with the micro-droplets of condensation liquid sprayed by the micro-droplet spraying device in the micro-droplet reaction zone; the micro-droplets after the condensation reaction fall into the liquid accumulation zone after passing through the spiral plate heat exchanger, and leave the condensation tower through the liquid discharge port;

[0023] When the countercurrent ventilation operation is performed, ketene gas enters the condensation tower from the second air inlet and outlet, passes through the gap in the spiral plate heat exchanger and the micro-droplet reaction zone in the condensation tower in turn, and then leaves the condensation tower from the first air inlet and outlet, and undergoes a condensation reaction with the condensation liquid micro-droplets sprayed by the micro-droplet spraying device in the micro-droplet reaction zone; the micro-droplets after the condensation reaction fall into the liquid accumulation zone after passing through the spiral plate heat exchanger, and leave the condensation tower through the liquid discharge port.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are:

[0025] 1) Aiming at the problem that the liquid film formed by the condensation liquid grid distributor at the top of the tower is too thick and the specific surface area is too small, the micro-droplet injection device proposed in the present invention forms a large number of micro-droplets after the condensation liquid passes through the micro-droplet injection device. The average particle size of the micro-droplets is about 150-300 μm, and the specific surface area of ​​the micro-droplets is about 20000-40000 m 2 / m 3 The surface area of ​​the liquid phase in the original liquid distributor is increased by hundreds to thousands of times, which greatly improves the gas-liquid contact area of ​​the condensation reaction, increases the reaction rate, and greatly shortens the condensation reaction time.

[0026] 2) In order to solve the problem of small specific surface area of ​​fillers, the present invention eliminates the filler layer in the condensation tower and replaces the filler layer with a micro-droplet settling reaction area. In this area, a large number of micro-droplets are formed by the micro-droplet injection device, and the specific surface area is about 20000-40000m 2 / m 3 , compared with the original specific surface area of ​​the packing layer 219 ~ 280m 2 / m 3 It is increased by 70 to 182 times. In this space, micro-droplets settle from the top of the tower under the action of gravity, and form co-current or counter-current contact with the ethylene ketone gas entering from the air inlet above or below the top of the tower, and a condensation reaction occurs. The reaction rate is greatly increased and the height of the condensation tower is greatly reduced.

[0027] 3) In order to solve the problem of insufficient heat exchange capacity of the heat exchange coil on the wall of the condensation tower, the present invention embeds a spiral plate heat exchanger in the tower body below the micro-droplet settling reaction area. The spiral plate heat exchanger is a multi-layer heat exchanger formed by curling the heat exchange plates along the same center and different radii. The refrigerant flows through the space inside the heat exchange plates, and the heat medium flows through the multi-layer annular space outside the heat exchange plates to achieve the purpose of heat exchange cooling. The spiral plate heat exchanger used can provide a heat exchange area of ​​59m per unit tower volume. 2 / m 3 Compared with the original tower wall, the coil heat exchanger inside and outside can provide a heat exchange area of ​​6m 2 / m 3It has been improved by about 10 times, ensuring the timely removal of reaction heat; and the spiral plate heat exchanger is evenly distributed in the radial direction of the condensation tower, which can directly remove the reaction heat in the tower. It is much better than the original tower wall coil heat exchanger that needs to transfer the reaction heat in the tower from the inside to the outside through the filler to the tower wall area for heat exchange, effectively avoiding the problem of local hot spots in the internal area of ​​the tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below in conjunction with the accompanying drawings.

[0029] Figure 1 It is a schematic diagram of the structure of the sorbic acid micro-droplet sedimentation condensation tower of the present invention.

[0030] Explanation of the reference numerals: 1. first air inlet and outlet; 2. micro-droplet injection device; 3. micro-droplet reaction zone; 4. spiral plate heat exchanger; 5. second air inlet and outlet; 6. liquid accumulation zone; 7. liquid discharge port. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] like Figure 1 As shown, the present invention provides a sorbic acid micro-droplet sedimentation condensation tower, comprising a condensation tower body with a hollow inner cavity, a first air inlet and outlet 1 is installed on the top side wall of the condensation tower body, a second air inlet and outlet 5 is installed on the bottom side wall of the condensation tower body, a micro-droplet injection device 2, a micro-droplet reaction zone 3 and a spiral plate heat exchanger 4 are sequentially arranged in the inner cavity of the condensation tower body from top to bottom, a liquid accumulation zone 6 is arranged at the bottom of the condensation tower body, and a liquid discharge port 7 is arranged at the bottom of the liquid accumulation zone 6.

[0033] Specifically, the horizontal setting height of the first air inlet and outlet 1 is higher than the horizontal setting height of the micro-droplet ejection device 2 .

[0034] Specifically, the micro-droplet injection device 2 adopts a liquid phase atomization nozzle, and the liquid phase atomization nozzle includes a solid cone nozzle, a hollow cone nozzle and / or an impact pin atomization nozzle.

[0035] Specifically, the horizontal setting height of the spiral plate heat exchanger 4 is higher than the horizontal setting height of the second air inlet and outlet 5 .

[0036] Specifically, the liquid accumulation area 6 is funnel-shaped, and the liquid discharge port 7 is arranged at the bottom center of the liquid accumulation area 6 .

[0037] Specifically, the spiral plate heat exchanger 4 is made of heat exchange plates, and the heat exchange plates are provided with multiple layers and are evenly distributed along the radial direction of the condensation tower.

[0038] Specifically, the condensation tower body consists of three parts, namely a middle cylinder, a sealing cover connected to the opening at the top of the cylinder, and a conical liquid accumulation area 6 connected to the bottom of the cylinder, wherein a first air inlet and outlet 1 is arranged at the sealing cover at the top of the cylinder, a second air inlet and outlet 5 is arranged on the bottom side wall of the middle cylindrical body, a micro-droplet injection device 2 is connected to the bottom end of the condensation liquid inlet pipe and is located in the column cavity of the middle cylinder, and the top end of the condensation liquid inlet pipe passes through the sealing cover at the top of the cylinder and is connected to the condensation liquid raw material storage chamber through a pump; in addition, the chamber of the middle cylinder below the micro-droplet injection device 2 is a micro-droplet reaction zone 3, a spiral plate heat exchanger 4 is embedded in the inner cavity of the cylinder, and the spiral plate heat exchanger 4 is located below the micro-droplet reaction zone 3 and above the second air inlet and outlet 5.

[0039] The present invention also provides a production method applied to the sorbic acid micro-droplet sedimentation condensation tower, comprising the following steps:

[0040] Step 1, spraying operation: spraying the condensed liquid raw material into the micro-droplet reaction zone 3 according to a preset liquid phase flow rate through the micro-droplet injection device 2;

[0041] Step 2, ventilation operation: while performing the spraying operation, the ketene gas is introduced into the condensation tower through the first gas inlet and outlet 1 or the second gas inlet and outlet 5 at a preset flow rate to perform a parallel flow ventilation operation or a counter-flow ventilation operation;

[0042] When the parallel flow ventilation operation is performed, the ketene gas enters the condensation tower from the first gas inlet and outlet 1, passes through the micro-droplet reaction zone 3 in the condensation tower and the gap in the spiral plate heat exchanger 4 in turn, and then leaves the condensation tower from the second gas inlet and outlet 5, and undergoes a condensation reaction with the condensation liquid micro-droplets sprayed by the micro-droplet spraying device 2 in the micro-droplet reaction zone 3; the micro-droplets after the condensation reaction fall into the liquid accumulation zone 6 after passing through the spiral plate heat exchanger 4, and leave the condensation tower through the liquid discharge port 7;

[0043] When countercurrent ventilation is performed, ketene gas enters the condensation tower from the second air inlet and outlet 5, passes through the gap in the spiral plate heat exchanger 4 and the micro-droplet reaction zone 3 in the condensation tower in turn, and then leaves the condensation tower from the first air inlet and outlet 1, and undergoes a condensation reaction with the condensation liquid micro-droplets sprayed by the micro-droplet spraying device 2 in the micro-droplet reaction zone 3; the micro-droplets that have undergone the condensation reaction fall into the liquid accumulation zone 6 after passing through the spiral plate heat exchanger 4, and leave the condensation tower through the liquid discharge port 7.

[0044] The advantages of the sorbic acid micro-droplet settling condensation tower provided by the present invention over the traditional packed condensation tower are respectively described by two specific embodiments of co-current / countercurrent ventilation operation:

[0045] Embodiment 1:

[0046] In the unfilled micro-droplet settling condensation tower with an inner diameter of 800 mm and a micro-droplet settling reaction area height of 1600 mm, the micro-droplet injection device adopts a solid cone liquid phase atomization nozzle, gas-liquid co-flow mode, and the condensation liquid raw material volume is 1m 3 , liquid flow rate 4m 3 / hr, ketene flow rate 120m 3 / hr, after 2.0 hours of reaction time, the reaction product value increased to 280, the product reached the qualified standard, and the reaction was completed. In a conventional packing condensation tower with an inner diameter of 800mm and a packing layer height of 1600mm, the reaction time takes 4.0 hours to complete. The use of a micro-droplet sedimentation condensation tower shortens the reaction time by 50%.

[0047] Embodiment 2:

[0048] In the unfilled micro-droplet settling condensation tower with an inner diameter of 800 mm and a micro-droplet settling reaction area height of 4800 mm, the micro-droplet injection device adopts a solid cone liquid phase atomization nozzle, gas-liquid countercurrent mode, and the condensation liquid raw material volume is 1m 3 , liquid flow rate 4m 3 / hr, ketene flow rate 120m 3 / hr, after 0.5 hours of reaction time, the reaction product value increased to 271, the product reached the qualified standard, and the reaction was completed. In a conventional packed condensation tower with an inner diameter of 800mm and a packing layer height of 4800mm, the reaction time took 2.0 hours to complete. The use of a micro-droplet sedimentation condensation tower shortened the reaction time by 75%.

[0049] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0050] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A sorbic acid micro-droplet sedimentation condensation tower, characterized in that: The invention comprises a condensation tower body with a hollow inner cavity, wherein a first air inlet and outlet (1) is installed on the top side wall of the condensation tower body, and a second air inlet and outlet (5) is installed on the bottom side wall of the condensation tower body. A micro-droplet injection device (2), a micro-droplet reaction zone (3) and a spiral plate heat exchanger (4) are sequentially arranged in the inner cavity of the condensation tower body from top to bottom, and a liquid accumulation zone (6) is arranged at the bottom of the condensation tower body, and a liquid discharge port (7) is arranged at the bottom of the liquid accumulation zone (6).

2. The sorbic acid droplet sedimentation condensation tower according to claim 1, characterized in that: The horizontal setting height of the first air inlet and outlet (1) is higher than the horizontal setting height of the micro-droplet ejection device (2).

3. The sorbic acid droplet sedimentation condensation tower according to claim 1, characterized in that: The micro-droplet injection device (2) adopts a liquid phase atomization nozzle, and the liquid phase atomization nozzle includes a solid cone nozzle, a hollow cone nozzle and / or an impact pin atomization nozzle.

4. The sorbic acid droplet sedimentation condensation tower according to claim 1, characterized in that: The horizontal setting height of the spiral plate heat exchanger (4) is higher than the horizontal setting height of the second air inlet and outlet (5).

5. The sorbic acid droplet sedimentation condensation tower according to claim 1, characterized in that: The liquid accumulation area (6) is funnel-shaped, and the liquid discharge port (7) is arranged at the bottom center of the liquid accumulation area (6).

6. The sorbic acid droplet sedimentation condensation tower according to claim 1, characterized in that: The spiral plate heat exchanger (4) is made of heat exchange plates, and the heat exchange plates are arranged in multiple layers and are evenly distributed along the radial direction of the condensation tower.

7. A production method for the sorbic acid micro-droplet sedimentation condensation tower according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1, spraying operation: spraying the condensed liquid raw material into the micro-droplet reaction zone (3) according to a preset liquid phase flow rate through the micro-droplet injection device (2); Step 2, ventilation operation: while performing the spraying operation, the ketene gas is introduced into the condensation tower through the first gas inlet and outlet (1) or the second gas inlet and outlet (5) at a preset flow rate to perform a parallel flow ventilation operation or a counter-flow ventilation operation; When performing a parallel flow ventilation operation, ketene gas enters the condensation tower from the first gas inlet and outlet (1), passes through the micro-droplet reaction zone (3) in the condensation tower and the gap in the spiral plate heat exchanger (4) in sequence, and then leaves the condensation tower from the second gas inlet and outlet (5), and undergoes a condensation reaction with the micro-droplets of condensation liquid sprayed by the micro-droplet spraying device (2) in the micro-droplet reaction zone (3); the micro-droplets that have undergone the condensation reaction fall into the liquid accumulation zone (6) after passing through the spiral plate heat exchanger (4), and leave the condensation tower through the liquid discharge port (7); When countercurrent ventilation is performed, ketene gas enters the condensation tower from the second gas inlet and outlet (5), passes through the gap in the spiral plate heat exchanger (4) and the micro-droplet reaction zone (3) in the condensation tower in turn, and then leaves the condensation tower from the first gas inlet and outlet (1), and undergoes a condensation reaction with the condensation liquid micro-droplets sprayed by the micro-droplet spraying device (2) in the micro-droplet reaction zone (3); the micro-droplets that have undergone the condensation reaction fall into the liquid accumulation zone (6) after passing through the spiral plate heat exchanger (4), and leave the condensation tower through the liquid discharge port (7).

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