2-chloro-5-chloromethylpyridine rectification device
By designing a jacketed series connection and stirring device in the distillation unit, the recycling of steam heat energy and the effective separation of toluene are realized, solving the problems of high energy consumption and low purity of traditional distillation units, and improving the purity and production efficiency of 2-chloro-5-chloromethylpyridine.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-01
- Publication Date
- 2026-03-24
AI Technical Summary
Traditional distillation units have low energy efficiency and do not recycle steam heat energy, resulting in high steam consumption per ton of product. Furthermore, it is difficult to completely separate low-boiling-point toluene, which affects the purity of 2-chloro-5-chloromethylpyridine.
The distillation vessel, finished product vessel, and pre-distillation vessel were designed in series with jackets to achieve the step-by-step transfer and recycling of steam heat energy. Combined with a stirring device and a vacuum system, the jacketed steam heating and condensate circulation form a closed-loop heat energy utilization, breaking the dissolution equilibrium of toluene and achieving efficient purification.
It improved the utilization rate of steam thermal energy, reduced energy consumption, significantly improved the purity and finished product quality of 2-chloro-5-chloromethylpyridine, reduced toluene residue, and lowered production costs.
Smart Images
Figure CN224024280U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a 2-chloro-5-chloromethyl pyridine production technical field, specifically to a 2-chloro-5-chloromethyl pyridine rectification device. BACKGROUND
[0002] In the industrial production of 2-chloro-5-chloromethyl pyridine, rectification and purification is the key process determining the purity of the product and the production cost. As a key intermediate of new nicotine insecticide, the compound has higher purity requirement, and the content of residual solvent toluene needs to be controlled below 0.1%. The purity directly affects the quality and efficacy of the final pesticide product. In industrial production, the purification of 2-chloro-5-chloromethyl pyridine is mainly realized by vacuum rectification technology. However, the traditional rectification process has the following problems:
[0003] The traditional rectification device has low energy utilization efficiency, and the rectification kettle, the front fraction tank and the product tank need to be heated independently. The steam heat is not recycled, and after single use, the steam heat energy is directly discharged. Especially, the waste heat recovery rate of the medium-low temperature steam in the later stage of rectification is insufficient, resulting in high steam consumption per ton of product.
[0004] If the crude product contains toluene solvent or by-product, the existing process is difficult to completely separate the low-boiling-point toluene, which easily causes toluene residue in the finished product, reducing the purity of 2-chloro-5-chloromethyl pyridine. UTILITY MODEL CONTENT
[0005] The main purpose of the utility model is to provide a rectification device capable of reducing energy consumption and improving the purity of 2-chloro-5-chloromethyl pyridine.
[0006] In order to achieve the above purpose, the technical scheme provided by the utility model is:
[0007] The utility model relates to a 2-chloro-5-chloromethyl pyridine rectification device, including rectification cauldron, the upper end of rectification cauldron is fixedly communicated with the lower end of rectification tower, the upper end of rectification tower is communicated with the feed end of condenser, the discharge end of condenser is communicated with the front fraction cauldron and the finished product cauldron, the upper end of front fraction cauldron and finished product cauldron is all communicated with the lower end of toluene cauldron, the upper end of toluene cauldron is communicated with tail gas treatment pipeline, rectification cauldron, front fraction cauldron, finished product cauldron and toluene cauldron are all jacketed cauldron, steam inlet pipe and steam outlet pipe are communicated with the jacket of rectification cauldron, steam return pipe is communicated with steam outlet pipe, installs the electromagnetic flow valve on steam return pipe, steam return pipe and steam inlet pipe are communicated with steam generator, steam outlet pipe is communicated with the import end of steam heater, the export end of steam heater is communicated with first steam pipe, installs temperature sensor on first steam pipe, the electromagnetic flow valve and temperature sensor are electrically connected with the starting switch of steam heater through controller, first steam pipe is communicated with the jacket of finished product cauldron, the jacket of finished product cauldron is communicated with the jacket of front fraction cauldron through second steam pipe, the jacket of front fraction cauldron is communicated with the import end of steam generator through steam exhaust pipe, and the condensing medium circulates in the jacket of toluene cauldron and carries out cooling to the toluene entering toluene cauldron.
[0008] Specifically, the rectification cauldron and the finished product cauldron are both provided with stirring devices.
[0009] Specifically, the condensing medium inlet and the condensing medium outlet of the condenser are communicated with a first condensing system.
[0010] Specifically, the jacket of the toluene cauldron is communicated with a second condensing system.
[0011] Specifically, the steam heater is a steam electric heater.
[0012] Specifically, the rectification cauldron is provided with a vacuum pumping system.
[0013] Compared with the prior art, the utility model has the beneficial effects that:
[0014] 1. The jackets of the rectification cauldron, the finished product cauldron and the front fraction cauldron are connected in series, so that the high-temperature steam is gradually transferred to the medium-low temperature steam, and the utilization rate of steam heat energy is improved. The steam discharged from the rectification cauldron is divided into two paths, one of which is directly returned to the steam generator through the steam return pipe, and the other of which is supplied to the finished product cauldron after being heated by the steam electric heater, so that a closed loop is formed and heat energy waste is avoided. The waste heat of the jacket of the front fraction cauldron is returned to the steam generator through the steam exhaust pipe, so that the low-grade heat energy is reused.
[0015] 2. The temperature sensor on the first steam pipe is linked with the controller, so that the power of the steam heater is dynamically adjusted, the temperature of the steam supplied to the finished product cauldron fluctuates little, and the heat conduction efficiency in the purification stage is maximized.
[0016] 3. The jacket steam heating of the product kettle and the forefraction kettle promotes the continuous vaporization and floating of residual toluene to the toluene kettle, and the forced convection of the stirring device breaks the solubility balance of toluene in the liquid phase, forming a circulating purification mechanism of heating, vaporization and trapping.
[0017] 4. The vacuum extraction system of the rectification kettle reduces the boiling point and reduces the decomposition of heat-sensitive substances. Combined with the staged cutting, the fraction switching is accurately controlled by the top temperature of the rectification column, avoiding the cross contamination of isomers.
[0018] 5. The stirring device arranged in the rectification kettle and the product kettle generates forced turbulence, eliminating the phenomenon of local overheating or subcooling, improving the uniformity of material heating, and significantly reducing the component segregation caused by temperature stratification. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 is a schematic diagram of the present rectification device.
[0020] Figure 2 is a schematic diagram of the steam outlet pipe, the steam return pipe and the connection of the first steam pipe and the steam heater.
[0021] The component names in the drawings are: 1, rectification kettle, 2, rectification column, 3, condenser, 4, forefraction kettle, 5, product kettle, 6, toluene kettle, 7, steam inlet pipe, 8, steam outlet pipe, 9, steam return pipe, 10, heater, 11, temperature sensor, 12, first steam pipe, 13, second steam pipe, 14, steam exhaust pipe, 15, electromagnetic flow valve. DETAILED DESCRIPTION
[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments.
[0023] Embodiment one: refer to Figures 1-2 As shown in the figure, a 2-chloro-5-chloromethylpyridine rectification device includes a rectification kettle 1, the rectification kettle 1 is a jacket kettle, and the upper end of the rectification kettle 1 is fixedly communicated with the lower end of a rectification column 2.
[0024] A vacuum extraction system is installed on the rectification kettle 1.
[0025] The upper end of the rectification column 2 is communicated with the inlet end of a condenser 3, and the condenser medium inlet and the condenser medium outlet of the condenser 3 are communicated with a first condensing system.
[0026] The discharge end of the condenser 3 is communicated with a forefraction kettle 4 and a product kettle 5. The forefraction kettle 4 and the product kettle 5 are both jacket kettles.
[0027] The upper end of the front fraction kettle 4 and the product kettle 5 is communicated with the lower end of the toluene kettle 6, and the toluene kettle 6 is a jacket kettle. The upper end of the toluene kettle 6 is communicated with the tail gas treatment pipeline.
[0028] The steam inlet pipe 7 and the steam outlet pipe 8 are communicated with the jacket of the rectification kettle 1, the steam return pipe 9 is communicated with the steam outlet pipe 8, and the electromagnetic flow valve 15 is installed on the steam return pipe 9.
[0029] The steam return pipe 9 and the steam inlet pipe 7 are communicated with the steam generator, the steam outlet pipe 8 is communicated with the inlet end of the steam heater 10, and the outlet end of the steam heater 10 is communicated with the first steam pipe 12.
[0030] The temperature sensor 11 is installed on the first steam pipe 12, the electromagnetic flow valve 15 and the temperature sensor 11 are electrically connected with the starting switch of the steam heater 10 through the controller, and the steam heater 10 is a steam electric heater 10.
[0031] The first steam pipe 12 is communicated with the jacket of the product kettle 5, the jacket of the product kettle 5 is communicated with the jacket of the front fraction kettle 4 through the second steam pipe 13, and the jacket of the front fraction kettle 4 is communicated with the inlet end of the steam generator through the steam discharge pipe 14.
[0032] The condensing medium circulates in the jacket of the toluene kettle 6 and cools the toluene entering the toluene kettle 6. Specifically, the jacket of the toluene kettle 6 is communicated with the second condensing system.
[0033] During rectification, the crude 2-chloro-5-chloromethylpyridine in the desolventizing kettle enters the rectification kettle 1, the vacuum system is started to vacuumize the rectification kettle 1, when the vacuum degree in the rectification kettle 1 reaches 730mmHg, the high-temperature steam in the steam generator enters the jacket of the rectification kettle 1 to carry out rectification.
[0034] When the rectification starts, the front fraction kettle 4 is opened, the product kettle 5 is closed, and the front fraction is cut. The front fraction is condensed by the condenser 3 and then enters the front fraction kettle 4.
[0035] When the top temperature of the rectification tower 2 reaches 90℃, the front fraction kettle 4 is closed, the product kettle 5 is opened, and the middle fraction is cut. The temperature of the cooling water entering the condenser 3 is stably controlled at 38±5℃. The middle fraction is condensed by the condenser 3 and then enters the product kettle 5, and the middle fraction in the product kettle 5 is the 2-chloro-5-chloromethylpyridine product.
[0036] After the heating steam is discharged from the jacket of the rectification kettle 1, it enters the steam outlet pipe 8, and part of the steam in the steam outlet pipe 8 flows back to the steam generator through the steam return pipe 9 and the electromagnetic flow valve 15 to be reheated.
[0037] Part of the steam in the steam outlet pipe 8 is sequentially reheated by the steam heater 10, the first steam pipe 12, the jacket of the product kettle 5, the second steam pipe 13, the jacket of the forefraction kettle 4 and the steam discharge pipe 14 and flows back to the steam generator.
[0038] When the steam flows through the jacket of the product kettle 5 and the jacket of the forefraction kettle 4, the steam can heat and purify the toluene in the 2-chloro-5-chloromethylpyridine product in the product kettle 5 and the forefraction in the forefraction kettle 4, and the toluene in the 2-chloro-5-chloromethylpyridine product and the forefraction is vaporized into the toluene kettle 6.
[0039] The temperature sensor 11 monitors the temperature of the steam entering the first steam pipe 12 in real time, and when the temperature entering the first steam pipe 12 is lower than the set temperature, the controller starts the steam heater 10 and increases the opening of the electromagnetic flow valve 15, so that most of the steam in the steam outlet pipe 8 flows back to the steam generator, and a small part of the steam in the steam outlet pipe 8 flows out from the first steam pipe 12 after being heated by the steam heater 10, which ensures the purification efficiency and effect of the 2-chloro-5-chloromethylpyridine product.
[0040] Example two: based on example one, referring to Figure 1 As shown in the figure, the rectification kettle 1 and the product kettle 5 are both provided with stirring devices.
[0041] When the crude 2-chloro-5-chloromethylpyridine is rectified, the stirring device in the rectification kettle 1 can stir the crude 2-chloro-5-chloromethylpyridine, so that the crude 2-chloro-5-chloromethylpyridine is uniformly heated and the rectification efficiency is improved.
[0042] When the 2-chloro-5-chloromethylpyridine product is purified, the stirring device in the product kettle 5 can stir the 2-chloro-5-chloromethylpyridine product, so that the 2-chloro-5-chloromethylpyridine product is uniformly heated and the purification efficiency is improved.
[0043] The above only describes the preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A 2-chloro-5-chloromethylpyridine rectification apparatus comprising a rectification kettle (1) and a rectification tower (2) fixedly communicated at the upper end of the rectification kettle (1) and the lower end of the rectification tower (2), characterized in that, The upper end of the rectifying tower (2) is communicated with the feed end of the condenser (3), the discharge end of the condenser (3) is communicated with the fore-fraction kettle (4) and the product kettle (5), the upper end of the fore-fraction kettle (4) and the product kettle (5) is communicated with the lower end of the toluene kettle (6), the upper end of the toluene kettle (6) is communicated with the tail gas treatment pipeline, the rectifying kettle (1), the fore-fraction kettle (4), the product kettle (5) and the toluene kettle (6) are all jacketed kettles, the steam inlet pipe (7) and the steam outlet pipe (8) are communicated with the jacket of the rectifying kettle (1), the steam return pipe (9) is communicated with the steam outlet pipe (8), the electromagnetic flow valve (15) is installed on the steam return pipe (9), the steam return pipe (9) and the steam inlet pipe (7) are communicated with the steam generator, the steam outlet pipe (8) is communicated with the inlet end of the steam heater (10), the outlet end of the steam heater (10) is communicated with the first steam pipe (12), the temperature sensor (11) is installed on the first steam pipe (12), the electromagnetic flow valve (15) and the temperature sensor (11) are electrically connected with the starting switch of the steam heater (10) through the controller, the first steam pipe (12) is communicated with the jacket of the product kettle (5), the jacket of the product kettle (5) is communicated with the jacket of the fore-fraction kettle (4) through the second steam pipe (13), the jacket of the fore-fraction kettle (4) is communicated with the inlet end of the steam generator through the steam discharge pipe (14), and the condensing medium circulates in the jacket of the toluene kettle (6) and cools the toluene entering the toluene kettle (6).
2. The apparatus for rectifying 2-chloro-5-chloromethylpyridine according to claim 1, wherein The rectifying kettle (1) and the product kettle (5) are both provided with stirring devices.
3. The apparatus of claim 1, wherein the 2-chloro-5-chloromethylpyridine is 2-chloro-5-chloromethylpyridine. The condensing medium inlet and the condensing medium outlet of the condenser (3) are communicated with the first condensing system.
4. The apparatus of claim 1, wherein the 2-chloro-5-chloromethylpyridine is 2-chloro-5-chloromethylpyridine. The jacket of the toluene kettle (6) is communicated with the second condensing system.
5. The 2-chloro-5-chloromethylpyridine distillation apparatus according to claim 1, characterized in that, The steam heater (10) is a steam electric heater.
6. The apparatus of claim 1, wherein the 2-chloro-5-chloromethylpyridine is 2-chloro-5-chloromethylpyridine. The rectifying kettle (1) is provided with a vacuum pumping system.