CN-121974806-A - Continuous thermal extraction method of catalyst in chloro-compound

CN121974806ACN 121974806 ACN121974806 ACN 121974806ACN-121974806-A

Abstract

The invention discloses a continuous thermal extraction method of a catalyst in chloro, which relates to the technical field of catalyst extraction, and adopts a double-packed tower serial continuous extraction system, wherein 90 ℃ hot water is used as an extractant, gradient separation of the catalyst is realized through a pulse reinforced mass transfer technology, the double-packed tower serial continuous extraction system comprises a control system, a first-stage extraction tower and a second-stage extraction tower which are connected in series, the control system adopts DCS to automatically adjust the temperature and flow of the first-stage extraction tower and the second-stage extraction tower, the first-stage extraction tower and the second-stage extraction tower are connected through a spiral plate type heat exchanger, and the double-packed tower serial continuous extraction system is connected with the pulse reinforced mass transfer technology in a series manner, so that the inter-phase contact is enhanced, the mass transfer effect is improved, repeated extraction operation is not needed, the treatment period is shortened, the consumption of the extractant is reduced, the nitro compound decomposition caused by temperature fluctuation is avoided, the byproduct generation is reduced, and the separation and purification difficulty of a subsequent working section is reduced.

Inventors

ZHANG JINLIANG
YANG WEIDONG
ZHANG YUCHAO
NIE JING
WANG CHANGSHENG
SHI MING
Qi jingxuan
ZHANG GUOXING

Assignees

浙江友联化学工业有限公司

Dates

Publication Date: 20260505
Application Date: 20260123

Claims (10)

1. A continuous thermal extraction method of a catalyst in chloro compounds is characterized in that a double-filler tower serial continuous extraction system is adopted, hot water at 90 ℃ is used as an extractant, gradient separation of the catalyst is realized through a pulse reinforced mass transfer technology, the double-filler tower serial continuous extraction system comprises a control system, a first-stage extraction tower and a second-stage extraction tower which are connected in series, the control system adopts DCS to automatically adjust the temperature and flow of the first-stage extraction tower and the second-stage extraction tower, and the first-stage extraction tower and the second-stage extraction tower are connected through a spiral plate type heat exchanger, and the method comprises the following steps: s1, pretreating a chloride raw material containing catalysts FeCl 3 and I 2 , and enabling the treated raw material to enter a primary extraction tower from the bottom of the tower at a flow rate of 20m 3 /h; S2, spraying hot water at 90+/-0.5 ℃ from the top of the primary extraction tower at a flow rate of 13.3m 3 /h, and carrying out countercurrent contact with the chlorinated material in the tower to carry out mass transfer reaction on a packing layer to obtain a primary raffinate phase; s3, cooling the primary raffinate phase to 87 ℃ through a spiral plate type heat exchanger, and then conveying the primary raffinate phase to a secondary extraction tower; s4, spraying hot water at 88+/-0.5 ℃ from the top of the secondary extraction tower at the flow rate of 6.7m 3 /h, and carrying out countercurrent contact with the primary raffinate phase to carry out deep extraction to obtain a purified organic phase and a secondary raffinate phase; S5, recovering trace organic products from the purified organic phase discharged from the top of the secondary extraction tower through a PP material coalescer, conveying the organic phase to a lower working section, and directly pumping the secondary raffinate water phase into an acidic wastewater treatment system in a factory after online pH detection.
2. The continuous thermal extraction method of catalyst in chloro-compound according to claim 1, wherein in step S1, the chloro-compound raw material is o-chloro-p-nitrotoluene mixture, and when the chloro-p-nitrotoluene mixture is pretreated, the o-chloro-p-nitrotoluene mixture is heated to 85+/-2 ℃ by a preheater.
3. The continuous thermal extraction method of the catalyst in the chloride, as set forth in claim 2, characterized in that in step S2, the operation temperature of the primary extraction tower is controlled at 88-92 ℃, the water-oil volume ratio is 1:1-2, the residence time of the raw materials in the tower is 20-30min, and more than 90% of the catalyst is rapidly removed, thus obtaining the primary raffinate phase with FeCl 3 content of 0.5%.
4. The method for continuous thermal extraction of catalyst in chloride according to claim 3, wherein the upper part of the primary extraction tower is provided with a packing layer filled with theta-ring packing, the lower part of the primary extraction tower is provided with a pulse sieve plate with an aperture ratio of 35%, the pulse sieve plate is positioned right below the packing layer and is connected with the packing layer up and down, a spiral nozzle distributor is arranged above the packing layer, and a first liquid distributor is arranged below the pulse sieve plate.
5. The continuous thermal extraction method of catalyst in chloride according to claim 4, wherein the pulse sieve plate is connected with a pulse generator driven by hydraulic pressure through a transmission component, the pulse generator outputs reciprocating motion power, the power directly acts on the pulse sieve plate through the transmission component and drives the pulse sieve plate to synchronously reciprocate up and down, the single pass of pulse amplitude is 25-50mm, and the total reciprocating distance of liquid column is 50-100mm.
6. The continuous thermal extraction method of catalyst in chloride according to claim 5, wherein the pulse sieve plate is a composite junction plate of a base plate and a coating layer, the base plate is a 316L stainless steel plate, and the coating layer is an integral lining polytetrafluoroethylene.
7. The continuous thermal extraction method of catalyst in chloro compound according to claim 6, wherein the theta ring filler in the filler layer is polytetrafluoroethylene theta ring filler, and the specific surface area of the theta ring filler is 250m 2 /m 3.
8. The continuous thermal extraction method of catalyst in chloride according to claim 7, wherein a coalescer made of PP material is arranged at the top of the secondary extraction tower, a hot water distributor is arranged below the coalescer, a packing pressing grid provided with a packing layer is arranged below the hot water distributor, a second liquid distributor is arranged below the packing layer, the operation temperature of the secondary extraction tower is controlled to be 86-89 ℃, the water-oil volume ratio is 1:2-3, and the residence time is 15-25min.
9. The continuous thermal extraction method of catalyst in chloride according to claim 8, wherein the coalescer is positioned in front of the light phase outlet at the top of the secondary extraction tower, the coalescer is a vertical pressure vessel with a filter element structure, and a plurality of filter elements with the pore diameter of 5 μm are arranged in the coalescer.
10. The continuous thermal extraction method of catalyst in chloride according to claim 1, wherein the control system comprises a control module, and a temperature sensor, a flow sensor, a pressure sensor and a pH sensor which are connected with the control module, wherein a gas phase space or a liquid phase outlet above a packing layer at the upper part of the primary extraction tower and inlet and outlet pipelines of the secondary extraction tower, a preheater inlet and outlet and an inlet and outlet of the spiral plate type heat exchanger are respectively provided with temperature detection points for being connected with the temperature sensor; the hot water feeding pipeline, the raw material feeding pipeline, the hot water feeding pipeline and the raffinate phase outlet pipeline of the secondary extraction tower are all provided with flow sensors; pressure sensors are arranged on inlet and outlet pipelines of a coalescer of the secondary extraction tower, the hot water storage tank and inlet and outlet pipelines of the spiral plate type heat exchanger; the pH sensor is arranged on a water phase outlet pipeline of the secondary extraction tower.

Description

Continuous thermal extraction method of catalyst in chloro-compound Technical Field The invention belongs to the technical field of catalyst extraction, and particularly relates to a continuous thermal extraction method of a catalyst in a chloride. Background 2B oil (2-chloro-4-aminotoluene) is an important organic intermediate, is widely applied to the industrial fields of dyes, pigments, medicines, pesticides and the like, chloro-compounds (o-chloro-p-nitrotoluene) are raw materials for synthesizing the 2B oil, chloro-compounds are synthesized by chloridizing p-nitrotoluene, and a catalyst participates in the reaction process and HCL is generated, so that the following treatment and purification are needed, and the industrial current production process mostly adopts batch stirred tank extraction and centrifugal continuous extraction processes; The method is characterized in that the method comprises the steps of carrying out extraction on a single-stage extraction process, wherein the core problems of the batch stirred tank extraction process are concentrated in three aspects of mass transfer efficiency, quality control and manual dependence, the single-stage extraction efficiency of the process is less than 85 percent, and in order to achieve the expected purification effect, 2-3 times of extraction operation are required to be repeatedly carried out, so that the time for treatment is long, a large amount of solvent is consumed, the solvent is mainly hot water, and the production cost is increased; Although the centrifugal continuous extraction process is improved in continuity, the centrifugal continuous extraction process is limited by mechanical structure and operation characteristics, and has a plurality of bottlenecks, namely, the processing capacity is limited, the single processing capacity of an industrial-grade centrifugal extractor is usually not more than 5m 3/h, and the processing capacity of a packing tower can reach 20m 3/h, if the requirements of large-scale production are met, a plurality of centrifugal extractors are required to be operated in series, and the energy consumption is directly increased by more than 30%; the method has the advantages that the equipment maintenance cost is high, the abrasion rate of the 316L material drum of the centrifugal extractor exceeds 0.1mm/1000h under the corrosion and abrasion action of chlorine-containing media, the core part is required to be replaced after the continuous operation for 6 months, the economic cost of equipment operation and maintenance is obviously improved, moreover, the high-speed rotation operation mode can lead the temperature of the system to rise to 8-12 ℃, the temperature rise is difficult to accurately control, the instability of the temperature can directly influence the selectivity coefficient of the extraction process, the fluctuation of the separation effect is caused, and meanwhile, the process also has the problems of incomplete catalyst separation and larger organic matter entrainment loss, thereby not only reducing the utilization rate of raw materials, but also influencing the purity of products; In summary, the existing two main stream extraction processes have the defects that the mass transfer efficiency, the processing capacity, the energy consumption control, the quality stability, the maintenance cost and the like are difficult to overcome, and the synchronous optimization of the purity, the energy consumption and the productivity in the chloro compound purification process cannot be realized. Disclosure of Invention The invention aims to provide a continuous thermal extraction method of a catalyst in a chloro compound, which can realize synchronous optimization of purity, energy consumption and productivity, and improve the purity of a product so as to solve the problems in the prior art. In order to achieve the above purpose, the invention adopts the following technical scheme: The continuous thermal extraction method of catalyst in chloro, adopt the serial continuous extraction system of double-packed tower, regard hot water of 90 degrees C as extractant, realize the gradient separation of catalyst through the pulse and strengthen the mass transfer technology, the serial continuous extraction system of double-packed tower includes control system and serial primary extraction tower and second extraction tower, the said control system adopts DCS to regulate temperature and flow of primary extraction tower and second extraction tower automatically, connect through the spiral plate type heat exchanger between the said primary extraction tower and second extraction tower, including the following steps: s1, pretreating a chloride raw material containing catalysts FeCl 3 and I 2, and enabling the treated raw material to enter a primary extraction tower from the bottom of the tower at a flow rate of 20m 3/h; S2, spraying hot water at 90+/-0.5 ℃ from the top of the primary extraction tower at a flow rate of 13.3m 3/