Naphthalene-free high-boiling-point aromatic hydrocarbon solvent rectification device

Abstract

The utility model relates to a naphthalene-free high-boiling-point aromatic solvent rectification device in the field of chemical equipment, which is characterized in that a light component outlet is arranged at the top of a rectification tower, a heavy component outlet is arranged at the bottom of the rectification tower, a plurality of packing layers are arranged in the rectification tower, the rectification tower comprises an upper tower, a middle tower and a lower tower from bottom to top, and the upper tower, the middle tower and the lower tower are cylindrical; the upper tower and the middle tower are connected through a reducing structure, and the middle tower and the lower tower are connected through a reducing structure; a C9 aromatic hydrocarbon inlet and a 1, 2, 4-trimethylbenzene outlet are formed in the side surface of the middle tower; a high-boiling-point aromatic hydrocarbon solvent SA1500 outlet is formed in the side surface of the lower tower; a high-boiling-point aromatic solvent SA1000 outlet and a methyl-ethylbenzene outlet are formed in the side surface of the upper tower; and a heat exchange jacket for gradient control of the temperature of each filler layer is arranged outside the rectifying tower. According to the device, light components, heavy components, methyl ethyl benzene, high-boiling-point aromatic solvents SA1500 and SA1000 and unsym-trimethylbenzene can be separated through internal reflux, the rectification energy consumption is low, and the separation effect is good.

Description

Technical Field

[0001] The utility model relates to chemical equipment, in particular to a distillation device for naphthalene-free high-boiling-point aromatic hydrocarbon solvents. Background Art

[0002] High-boiling-point aromatic hydrocarbon solvents, an indispensable cornerstone of organic chemistry, possess distinct and diverse properties. These solvents are renowned for their exceptionally high boiling points, strong dissolving power, slow volatility, and near-odorlessness. Furthermore, they contain no harmful chlorine or heavy metals, exhibiting extremely low toxicity levels, and possess high flash points for enhanced safety. Their exceptional penetrating power, stable chemical properties, and excellent leveling properties provide a solid foundation for their diverse applications.

[0003] Naphthalene-free or low-naphthalene high-boiling-point aromatic solvents play a vital role in applications such as high-end coatings, plastic resins, silver paste preparation, pharmaceutical manufacturing, as extractants in hydrogen peroxide production, and in the production of printing inks. They are also widely used in the formulation of advanced baking varnish solvents, the preparation of insecticide emulsions, and the dissolution of rubber resins, fully demonstrating their versatility and broad adaptability.

[0004] With the continuous rise of global environmental awareness and increasingly stringent environmental regulations, restrictions on the naphthalene content in high-boiling-point aromatic solvents are becoming increasingly stringent. This trend requires continuous process optimization to reduce naphthalene content during production. However, the production processes for naphthalene-free or low-naphthalene high-boiling-point aromatic solvents currently on the market are generally complex and energy-intensive, undoubtedly posing significant challenges to manufacturers.

[0005] Therefore, we need to actively explore and develop more efficient and environmentally friendly production processes while ensuring product quality to meet the growing market demand for naphthalene-free or low-naphthalene high-boiling-point aromatic solvents. At the same time, we also need to strengthen our technological research and development and innovation capabilities to promote technological progress and industrial upgrading in this field.

[0006] CN104926582A discloses a method for preparing a low-naphthalene aromatic hydrocarbon solvent. The preparation process comprises: introducing a C heavy aromatic hydrocarbon feedstock into a vacuum distillation tower, controlling the conditions of the vacuum distillation tower, and extracting the low-naphthalene aromatic hydrocarbon solvent at the top of the tower. The present invention provides a method for preparing a low-naphthalene aromatic hydrocarbon solvent. The method has a simple process flow and significantly reduces the banned content in the GF-S1500 aromatic hydrocarbon solvent through the rational setting of the distillation process. After spraying pesticides dissolved in the low-naphthalene aromatic hydrocarbon solvent, no naphthalene residue is left on crops. The method has the advantages of good efficacy and high safety.

[0007] CN207452025U relates to a device for preparing a low-naphthalene high-boiling-point aromatic hydrocarbon solvent. The device provides a device for preparing a C10 aromatic low-naphthalene high-boiling-point aromatic hydrocarbon solvent, comprising a multi-stage distillation device, a crystallization device and a liquid-solid separation device connected in series in sequence; the multi-stage distillation device comprises a first-stage distillation tower, a second-stage distillation tower, a third-stage distillation tower and a fourth-stage distillation tower connected in series in sequence; the top of each distillation tower is provided with a condensing reflux device, the bottom of each distillation tower is provided with a heater, the side of each distillation tower is provided with a feed port, and the middle side of the fourth-stage distillation tower is provided with a discharge port connected to the crystallization device; the bottom material outlet of the upper distillation tower is connected to the feed port of the adjacent lower distillation tower through a connecting pipeline. The naphthalene content of the C10 aromatic low-naphthalene high-boiling-point aromatic hydrocarbon solvent obtained by the utility model is lower than the enterprise standard, and the utility model is pollution-free and has good environmental protection performance.

[0008] The disadvantage is that the existing distillation device has the problem of unreasonable stratification of the fillers in the distillation tower, which requires continuous external reflux to separate materials with different boiling points, resulting in high energy consumption and poor separation effect. Utility Model Content

[0009] The utility model aims to provide a naphthalene-free high-boiling-point aromatic hydrocarbon solvent distillation device, which can separate light components, heavy components, methyl and ethyl benzene, high-boiling-point aromatic hydrocarbon solvents SA1500, SA1000 and trimethylolbenzene through internal reflux, and has low distillation energy consumption.

[0010] The purpose of the utility model is achieved as follows: a naphthalene-free high-boiling point aromatic solvent distillation device, comprising a vertical distillation tower, a light component outlet is provided at the top of the distillation tower, a heavy component outlet is provided at the bottom, a plurality of packing layers are provided in the distillation tower, and a gas-liquid separation cavity is left above and below each packing layer, the distillation tower comprises an upper tower, a middle tower and a lower tower from bottom to top, the upper tower, the middle tower and the lower tower are cylindrical in shape, the upper tower and the middle tower, the middle tower and the lower tower are connected by a reducing structure, the packing layer provided in the upper tower has four layers, the middle tower is provided There are three layers of packing in the middle tower, and two layers of packing in the lower tower; a C9 aromatics inlet is provided on the side wall above the upper packing layer of the middle tower, and a trimethylbenzene outlet is provided on the side wall above the lower packing layer of the middle tower; a high-boiling-point aromatic solvent SA1500 outlet is provided on the side wall between the two packing layers of the lower tower; a high-boiling-point aromatic solvent SA1000 outlet is provided on the side wall above the lowest packing layer of the upper tower, and a methyl and ethylbenzene outlet is provided on the side wall below the highest packing layer of the upper tower. A heat exchange jacket is provided outside the distillation tower for gradient control of the temperature of each packing layer.

[0011] During operation, C9 aromatics at 110~120℃ are fed from the C9 aromatics inlet and distilled under reduced pressure at 19~22KPa. SA1000 (19~22KPa, 100~110℃) and methyl and ethyl benzene (19~22KPa, 90~100℃) are sequentially discharged from the side line of the distillation tower. Light components (19~22KPa, 70~90℃) are discharged from the top of the distillation tower. Trimethylbenzene (19~22KPa, 120~140℃) and SA1500 (19~22KPa, 140~160℃) are sequentially discharged from the side line of the distillation tower. Heavy components (19~22KPa, 160~180℃) are discharged from the bottom of the distillation tower. The main components of the high-boiling-point aromatic solvent SA1500 are trimethylbenzene and tetramethylbenzene. 00The main components are n-propylbenzene, isopropylbenzene, ethylmethylbenzene, and mesitylene; the function of the packing layer is to separate the upper and lower channels very well. On the one hand, it can facilitate temperature zoning control so that relatively higher boiling point materials can be condensed at specific packing layer positions, while allowing relatively lower boiling point materials to evaporate and pass through the packing layer. Therefore, the packing layer has the dual functions of evaporation and material capture, allowing the liquid material to be discharged from the corresponding outlet on the side wall, while allowing the low-boiling point material to vaporize and ascend through the packing layer where it is located until it reaches a packing layer with a lower boiling point temperature than itself. The low-boiling point material condenses into liquid and is discharged from the corresponding outlet. Finally, the light component at the top leaves in a gaseous state, which can be further condensed into liquid. The heavy component after distillation sinks to the bottom of the lower tower and can eventually be discharged from the heavy component outlet. The utility model adopts the arrangement of a three-layer distillation tower with a larger upper layer and a smaller lower layer, so that the material has sufficient evaporation space in the corresponding packing layer, and the condensed liquid has a larger collection area, thereby having better evaporation and capture effects. It does not need to be separated by external reflux, and light components, heavy components, methyl and ethyl benzene, high-boiling point aromatic solvents SA1500, SA1000 and trimethylol can be separated only by internal reflux. The distillation energy consumption is low and the separation effect is good. The device can be used for the distillation of C9, C10 and C11 aromatic hydrocarbons.

[0012] A further improvement of the present invention is that the height ratio of the lower, middle, and upper towers is 2:(3-3.5):(5-5.5). Furthermore, the diameter ratio of the lower, middle, and upper towers is 1:(1.2-1.4):(1.6-1.8). Within this numerical range, the temperature of each outlet is easily controlled, and materials at different temperatures can be clearly separated.

[0013] In order to further facilitate the temperature gradient control, the heat exchange jackets are provided with multiple independent heat exchange jackets from top to bottom. The temperature gradient control from top to bottom can be achieved through the multiple independent heat exchange jackets.

[0014] The packing layer comprises multiple layers of stacked corrugated plates in a broken-line shape, with raised discs located at the crests and troughs of the corrugated plates, the discs being partially connected to the corrugated plates, and flow holes corresponding to the discs being left on the corrugated plates. Furthermore, the straight lines on which the crests of two adjacent corrugated plates lie are parallel to each other or arranged perpendicular to each other in space. The packing layer is arranged as a packing layer in a low-naphthalene, high-boiling-point aromatic solvent distillation tower. During fraction separation, gas can gradually converge along the lower surface of the corrugated plates toward the underside of the crests, then move upward through the liquid flow holes of the layer, and sequentially pass through the liquid flow holes layer by layer to exit from the top of the distillation tower; condensed liquid can gradually converge toward the underside of the troughs, then move downward through the corresponding liquid flow holes, thereby achieving gas-liquid separation. The device has excellent heat and mass transfer performance, low reaction resistance, low distillation energy consumption, and good separation effect, resulting in good continuity and stability in the distillation of low-naphthalene products.

[0015] Furthermore, the corrugated plate has a thickness of 1-2 mm, the disc has a diameter of 0.8-5 cm, and each packing layer is stacked with 50-300 layers of corrugated plate. By stacking multiple layers, the packing layer can quickly transfer heat and mass, thereby achieving the technical effect of efficient and rapid separation of substances with different boiling points. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic structural diagram of the utility model.

[0017] Figure 2 Schematic diagram of the packing layer structure.

[0018] Figure 3 It is a schematic plan view of the local structure of a single-layer Bowen plate.

[0019] Figure 4 This is a three-dimensional diagram of the local structure of a single-layer Bowen plate.

[0020] In the figure, 1 is the heavy component outlet, 2 is the heat exchange jacket, 3 is the high boiling point aromatic solvent SA1500 outlet, 4 is the trimethylolbenzene outlet; 5 is the C9 aromatics inlet, 6 is the high boiling point aromatic solvent SA1000 outlet, 7 is the methyl and ethylbenzene outlet, 8 is the light component outlet, 9 is the packing layer, 9a is the peak, 9b is the trough, 9c is the disc, 9d is the flow hole, L1 is the upper tower, L2 is the middle tower, and L3 is the lower tower. DETAILED DESCRIPTION

[0021] like Figure 1-4As shown, a naphthalene-free high-boiling point aromatic solvent distillation device includes a vertical distillation tower, a light component outlet 8 is provided at the top of the distillation tower, a heavy component outlet 1 is provided at the bottom, a plurality of packing layers 9 are provided in the distillation tower, and a gas-liquid separation cavity is left above and below each packing layer 9. The distillation tower includes an upper tower L1, a middle tower L2 and a lower tower L3 from bottom to top. The upper tower L1, the middle tower L2 and the lower tower L3 are cylindrical in shape. The upper tower L1 and the middle tower L2, and the middle tower L2 and the lower tower L3 are connected by a reducing structure. The packing layer 9 provided in the upper tower L1 has four layers, and the packing layer 9 provided in the middle tower L2 has 9 layers. There are three layers, and there are two layers of packing layers 9 arranged in the lower tower L3; a C9 aromatic hydrocarbon inlet 5 is provided on the side wall above the upper packing layer 9 of the middle tower L2, and a trimethylbenzene outlet 4 is provided on the side wall above the lower packing layer 9 of the middle tower L2; a high-boiling-point aromatic hydrocarbon solvent SA1500 outlet 3 is provided on the side wall between the two packing layers 9 of the lower tower L3; a high-boiling-point aromatic hydrocarbon solvent SA1000 outlet 6 is provided on the side wall above the lowermost packing layer 9 of the upper tower L1, and a methyl and ethylbenzene outlet 7 is provided on the side wall below the uppermost packing layer 9 of the upper tower L1. A heat exchange jacket 2 is provided outside the distillation tower for gradient controlling the temperature of each packing layer 9.

[0022] The height ratio of lower tower L3, middle tower L2, and upper tower L1 is 2:(3-3.5):(5-5.5). The diameter ratio of lower tower L3, middle tower L2, and upper tower L1 is 1:(1.2-1.4):(1.6-1.8). Within this range, the temperature of each outlet is easily controlled, and materials at different temperatures can be clearly separated.

[0023] In order to further facilitate the temperature gradient control, a plurality of independent heat exchange jackets 2 are provided from top to bottom. The plurality of independent heat exchange jackets 2 can realize the temperature gradient control from top to bottom.

[0024] The packing layer 9 comprises multiple layers of stacked corrugated plates in a broken-line shape. The crests 9a and troughs 9b of the corrugated plates are each provided with a raised disc 9c. The disc 9c is partially connected to the corrugated plates, and the corrugated plates have flow holes 9d corresponding to the disc 9c. The packing layer 9 is arranged in a low-naphthalene, high-boiling-point aromatic hydrocarbon solvent distillation tower. During fraction separation, gas can gradually converge along the lower surface of the corrugated plates toward the underside of the crests 9a, then move upward through the liquid flow holes in the layer, and sequentially pass through the liquid flow holes layer by layer to exit the top of the distillation tower. Condensed liquid can gradually converge toward the underside of the troughs 9b, then move downward through the corresponding liquid flow holes, thereby achieving gas-liquid separation. The device has excellent heat and mass transfer performance, low reaction resistance, low distillation energy consumption, and excellent separation effect, resulting in continuous and stable distillation of low-naphthalene products.

[0025] The corrugated sheet has a thickness of 1-2 mm, and the diameter of the discs 9c is 0.8-5 cm. Each packing layer 9 is stacked with 50-300 layers of corrugated sheet. This multi-layer stacking allows for rapid heat and mass transfer in the packing layer 9, thereby achieving the technical effect of efficiently and quickly separating substances with different boiling points. The corrugated sheet is made from stainless steel sheet. During processing, the sheet is first cut to the appropriate size. An array of discs 9c, each partially connected to the sheet, is then punched out of the sheet. The sheet is then bent. During bending, the discs 9c are positioned at either the peaks 9a or the troughs 9b. When the peaks 9a and troughs 9b are formed, the discs 9c tilt upward, forming flow holes 9d in the sheet. Finally, the sheet is stacked and welded to form a low-naphthalene, high-boiling-point aromatic solvent distillation tower packing device. During stacking and welding, gaps can be reserved between adjacent corrugated sheets. During welding, the straight lines along which the peaks 9a of two adjacent corrugated sheets lie parallel to each other or perpendicular to each other in space.

[0026] When the distillation tower is working, C9 aromatics at 110~120℃ are fed from C9 aromatics inlet 5 and are distilled under reduced pressure at 19~22KPa; SA1000 (19~22KPa, 100~110℃) and methyl and ethyl benzene (19~22KPa, 90~100℃) are sequentially discharged from the side line of the distillation tower; light components (19~22KPa, 70~90℃) are discharged from the top of the distillation tower; trimethylbenzene (19~22KPa, 120~140℃) and SA1500 (19~22KPa, 140~160℃) are sequentially discharged from the side line of the distillation tower; heavy components (19~22KPa, 160~180℃) are discharged from the bottom of the distillation tower, among which the main component of the high boiling point aromatic solvent SA1500 is mixed tetramethylbenzene; high boiling point aromatic solvent SA10 00The main component is mixed trimethylbenzene; the function of the packing layer 9 is to separate the upper and lower channels very well. On the one hand, it is convenient to carry out temperature zoning control so that relatively higher boiling point materials can be condensed at a specific position of the packing layer 9, while allowing relatively lower boiling point materials to evaporate and pass upward through the packing layer 9. Therefore, the packing layer 9 has the dual functions of evaporation and material capture, allowing the liquid material to be discharged from the corresponding outlet on the side wall, and allowing the low-boiling point material to vaporize and pass upward through the packing layer 9 until it reaches the packing layer 9 with a temperature lower than its boiling point. The low-boiling point material condenses into liquid and is discharged from the corresponding outlet. Finally, the light component at the top leaves in a gaseous state, which can be further condensed into liquid later. The heavy component after distillation sinks to the bottom of the lower tower L3 and can eventually be discharged from the heavy component outlet. The device adopts a three-layer distillation tower with a larger upper layer and a smaller lower layer, so that the material has sufficient evaporation space in the corresponding packing layer 9, and the condensed liquid has a larger collection area, thereby having better evaporation and capture effects. It does not need to be separated by external reflux, and light components, heavy components, ethyl and methylbenzene, high-boiling point aromatic solvents SA1500, SA1000 and trimethylolbenzene can be separated only by internal reflux. The distillation energy consumption is low and the separation effect is good. The device can be used for the distillation of C9, C10, and C11 aromatic hydrocarbons. The C9 aromatic hydrocarbon inlet 5 only indicates its position. As the feed composition changes, it can also become the C10 and C11 aromatic hydrocarbon inlet.

[0027] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solutions disclosed in the present invention, technicians in this field can make some substitutions and deformations of some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A naphthalene-free high-boiling-point aromatic solvent distillation device, comprising a vertical distillation tower, a light component outlet at the top of the distillation tower, a heavy component outlet at the bottom, a plurality of packing layers provided in the distillation tower, a gas-liquid separation cavity being respectively left above and below each packing layer, characterized in that: The distillation tower includes an upper tower, a middle tower and a lower tower from bottom to top. The upper tower, the middle tower and the lower tower are cylindrical in shape. The upper tower and the middle tower, as well as the middle tower and the lower tower are connected via a reducing structure. There are four packing layers in the upper tower, three packing layers in the middle tower, and two packing layers in the lower tower. A C9 aromatic hydrocarbon inlet is provided on the side wall above the upper packing layer of the middle tower, and a trimethylbenzene outlet is provided on the side wall above the lower packing layer of the middle tower. A high-boiling-point aromatic hydrocarbon solvent SA1500 outlet is provided on the side wall between the two packing layers of the lower tower. A high-boiling-point aromatic hydrocarbon solvent SA1000 outlet is provided on the side wall above the lowest packing layer of the upper tower, and a methyl and ethylbenzene outlet is provided on the side wall below the highest packing layer of the upper tower. A heat exchange jacket for gradient controlling the temperature of each packing layer is provided on the outside of the distillation tower.

2. A naphthalene-free high-boiling-point aromatic hydrocarbon solvent rectification device according to claim 1, characterized in that: The height ratio of the lower tower, middle tower and upper tower is 2: (3-3.5): (5-5.5).

3. A naphthalene-free high-boiling-point aromatic hydrocarbon solvent rectification device according to claim 1, characterized in that: The diameter ratio of the lower tower, middle tower and upper tower is 1: (1.2-1.4): (1.6-1.8).

4. A naphthalene-free high-boiling-point aromatic hydrocarbon solvent rectification device according to any one of claims 1 to 3, characterized in that: The heat exchange jackets are provided in a plurality of independent ones from top to bottom.

5. A naphthalene-free high-boiling-point aromatic hydrocarbon solvent distillation device according to any one of claims 1 to 3, characterized in that: The packing layer includes multiple layers of stacked corrugated plates, which are in a broken line shape. The crests and troughs of the corrugated plates are respectively provided with raised discs, which are partially connected to the corrugated plates, and the corrugated plates are provided with flow holes corresponding to the discs.

6. A naphthalene-free high-boiling-point aromatic hydrocarbon solvent rectification device according to claim 5, characterized in that: The straight lines where the wave crests of two upper and lower adjacent corrugated plates are located are parallel to each other or vertically arranged to each other.

7. A naphthalene-free high-boiling-point aromatic hydrocarbon solvent rectification device according to claim 5, characterized in that: The corrugated board has a thickness of 1-2 mm, the disc has a diameter of 0.8-5 cm, and each packing layer is stacked with 50-300 layers of corrugated boards.

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