Device for generating alcohol ketone dibasic acid ester through one-step oxidation of cyclohexane

Abstract

A device for generating alcohol ketone dibasic acid ester through one-step oxidation of cyclohexane comprises at least one reactor, a first washing tower and a second washing tower, a washing cavity is formed in the top of the reactor, an oxygen source distributor is arranged at the bottom of the reactor, a first feeding port is formed in the bottom of the reactor, an overflow port is formed in the side wall of the reactor, a second feeding port is formed in the washing cavity, and an exhaust port is formed in the top of the washing cavity. A first air inlet is formed in the lower portion of the side wall of the first washing tower, a first washing liquid inlet is formed in the upper portion of the side wall of the first washing tower, a second air inlet is formed in the lower portion of the side wall of the second washing tower, and a second washing liquid inlet is formed in the upper portion of the side wall of the second washing tower. The first washing liquid inlet is connected with a desalted water source and a liquid alkali source, the second gas inlet is connected with the top of the first washing tower through a pipeline, and the second washing liquid inlet is connected with an alcohol ketone source. The device is simple in structure and convenient to maintain, and effectively avoids environmental pollution on the basis of guaranteeing long-time normal and stable operation.

Description

Technical Field

[0001] The utility model relates to the field of chemical industry, in particular to a device for generating alcohol ketone dibasic acid ester by one-step oxidation of cyclohexane. Background Art

[0002] Cyclohexane is an important chemical intermediate. Cyclohexane oxidation produces alcohol ketone dibasic acid esters, among which cyclohexanol, cyclohexanone and dibasic acid esters are important chemical raw materials and can be used to produce caprolactam and nylon-66. At present, cyclohexane catalytic oxidation has replaced cyclohexane non-catalytic oxidation. Compared with non-catalytic oxidation, cyclohexane catalytic oxidation has the following advantages:

[0003] 1. The required amount of catalyst is small, the process flow is short, the number of equipment is significantly reduced, and the total investment of the device is small;

[0004] 2. The operating temperature of cyclohexane catalytic oxidation process is low, and the process is simple and reliable;

[0005] 3. The supporting decomposition system and separation system have short process flow and save energy and reduce consumption.

[0006] However, the production equipment currently in use uses compressed air as the oxygen source, and excess air carries cyclohexane and alcohol ketone dibasic acid ester products into the scrubbing tower through the exhaust pipeline. The dibasic acid esters carried by the air crystallize in the exhaust pipeline, causing the exhaust pipeline to be blocked. In addition, the supporting scrubbing tower cannot effectively remove organic matter mixed in the exhaust gas, and also causes environmental pollution.

[0007] Therefore, how to ensure the long-term normal operation of production equipment is an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0008] The utility model aims to provide a device for one-step oxidation of cyclohexane to generate alcohol-ketone dibasic acid in view of the deficiencies in the prior art. The device has a simple structure and is easy to maintain. On the basis of ensuring long-term normal and stable operation, environmental pollution can be effectively avoided.

[0009] The technical scheme for realizing the purpose of the utility model is: a device for one-step oxidation of cyclohexane to generate alcohol ketone dibasic acid ester, comprising a reaction system and a tail gas treatment system, wherein the reaction system comprises at least one reactor, a washing chamber is arranged at the top of the reactor, an oxygen source distributor is arranged at the bottom, a first feed inlet is arranged at the bottom of the reactor, an overflow port is arranged at the side wall, a second feed inlet is arranged at the washing chamber, and a first exhaust port is arranged at the top, the tail gas treatment system comprises a first washing tower and a second washing tower, a washing liquid circulation pipeline is arranged at the bottom of each washing tower, a first air inlet is arranged at the lower part of the side wall of the first washing tower, and a first washing liquid inlet is arranged at the upper part of the side wall, a second air inlet is arranged at the lower part of the side wall of the second washing tower, and a second washing liquid inlet is arranged at the upper part of the side wall, the first feed inlet and the second feed inlet of the reaction system are both connected to a cyclohexane source, the first exhaust port is connected to the first air inlet of the tail gas treatment system, the first washing liquid inlet of the tail gas treatment system is connected to a desalted water source and a liquid alkali source, the second air inlet is connected to the top of the first washing tower through a pipeline, and the second washing liquid inlet is connected to an alcohol ketone source.

[0010] Furthermore, it also includes a third washing tower, wherein a liquid outlet is arranged at the bottom of the third washing tower, a third air inlet is arranged at the lower part of the side wall, and a third washing liquid inlet is arranged at the upper part of the side wall, the liquid outlet is connected to the first feed inlet and the second feed inlet of the reaction system, the third air inlet is connected to the first exhaust port of the reactor, the first air inlet of the first washing tower is connected to the top of the third washing tower through a pipeline, and the third washing liquid inlet is connected to the cyclohexane source.

[0011] Preferably, the number of the third washing towers is two, which are connected in series to form a whole, and the oxygen source distributor is connected to a compressed air source and / or a compressed oxygen source.

[0012] Preferably, the first washing tower, the second washing tower and the third washing tower are all packed towers, each air inlet is located below the packing of the corresponding washing tower, and each washing liquid inlet is located above the packing of the corresponding washing tower.

[0013] Furthermore, a second exhaust port is provided at the top of the reactor, and the second exhaust port is provided with a valve, which is connected to the air inlet of the washing tower in parallel with the first exhaust port.

[0014] Preferably, there are multiple reactors connected in series to form a whole, the overflow port of the upstream reactor is connected to the first feed port of the downstream reactor, and the second feed ports of each reactor are connected in parallel.

[0015] Furthermore, it also includes a distillation system, wherein the liquid inlet end of the distillation system is connected to the overflow port of the reactor through a buffer tank, and the distillation system is provided with a desalted water pipe.

[0016] The above technical solution has the following beneficial effects:

[0017] 1. The utility model discloses a device for one-step oxidation of cyclohexane to generate alcohol ketone and dibasic acid ester, comprising a reaction system and an exhaust gas treatment system, wherein the reaction system is used for one-step oxidation to generate alcohol ketone and dibasic acid ester as byproduct, wherein the exhaust gas treatment system is used for washing reaction exhaust gas. The reaction system comprises at least one reactor, wherein a washing chamber is arranged at the top of the reactor, an oxygen source distributor is arranged at the bottom, a first feed inlet is arranged at the bottom of the reactor, an overflow port is arranged at the side wall, a second feed inlet is arranged at the washing chamber, and a first exhaust port is arranged at the top, air or oxygen is evenly distributed at the bottom of the reactor through the oxygen source distributor, and excess air or oxygen is discharged from the reactor through the washing chamber and the first exhaust port of the reactor, the first feed inlet and the second feed inlet are both used for adding cyclohexane into the reactor, and the cyclohexane added at the second feed inlet is used to wash the exhaust gas discharged from the washing chamber, thereby reducing the content of organic matter carried by the discharged exhaust gas, and in addition, by flushing the washing chamber with cyclohexane, the pipe blocking phenomenon caused by crystallization of organic matter (mainly dibasic acid) carried in the exhaust pipeline can be prevented, thereby ensuring the normal operation of the reactor for a long time. The tail gas treatment system includes a first washing tower and a second washing tower, and a washing liquid circulation pipeline is arranged at the bottom of each washing tower to make full use of the washing liquid. A first air inlet is arranged at the lower part of the side wall of the first washing tower, and a first washing liquid inlet is arranged at the upper part of the side wall, and a second air inlet is arranged at the lower part of the side wall of the second washing tower, and a second washing liquid inlet is arranged at the upper part of the side wall. The first feed port and the second feed port of the reaction system are both connected to a cyclohexane source for adding cyclohexane, the first exhaust port is connected to a first air inlet of a tail gas treatment system, the first washing liquid inlet of the tail gas treatment system is connected to a desalted water source and a liquid alkali source, the second air inlet is connected to the top of a first washing tower through a pipeline, the second washing liquid inlet is connected to an alcohol ketone source, the tail gas after preliminary treatment enters the first washing tower through the first air inlet, alkali solution and desalted water are used as washing liquids, most of the dibasic acids (which react with alkali solution and are easily soluble in desalted water) are eluted, the tail gas carrying alcohol ketones (cyclohexanol, cyclohexanone) enters the second washing tower through the second air inlet, and alcohol ketones are used as washing liquids to elute most of the alcohol ketones, and then the tail gas is discharged to the tail gas treatment system, so that the content of organic matter therein can be reduced to less than 0.5%.

[0018] 2. It also includes a third washing tower, wherein a liquid outlet is arranged at the bottom of the third washing tower, a third air inlet is arranged at the lower part of the side wall, and a third washing liquid inlet is arranged at the upper part of the side wall, the liquid outlet is connected to the first feed inlet and the second feed inlet of the reaction system, the third air inlet is connected to the first exhaust port of the reactor, the first air inlet of the first washing tower is connected to the top of the third washing tower through a pipeline, and the third washing liquid inlet is connected to the cyclohexane source, that is, the cyclohexane as the raw material is first used as the washing liquid through the third washing tower and enters the reactor through the first feed inlet and the second feed inlet, and the exhaust gas that has been preliminarily treated is washed in the third washing tower, so that the cyclohexane and part of the alcohol ketone carried in the exhaust gas are refluxed to the reactor, and in addition, the exhaust gas is cooled, and the washing and absorption efficiency of the downstream washing tower is also improved.

[0019] 3. A second exhaust port is provided on the top of the reactor. The second exhaust port is provided with a valve. It is connected to the air inlet of the washing tower in parallel with the first exhaust port. According to actual conditions, the tail gas can be discharged from the reactor through the second exhaust port to meet the actual needs of the enterprise.

[0020] 4. It also includes a distillation system, wherein the liquid inlet end of the distillation system is connected to the overflow port of the reactor through a buffer tank, and the distillation system is provided with a desalted water pipe. The reaction liquid (oxidation liquid) containing alcohol ketone and dibasic acid ester overflows into the buffer tank and enters the distillation system in a steady flow. By controlling the distillation temperature of the distillation system, the small molecular raw materials and impurities therein are separated in the form of vapor phase, while the alcohol ketone and dibasic acid ester are retained in the bottom liquid to increase the concentration, and desalted water is added through the desalted water pipe to dissolve as much dibasic acid as possible, and finally a high-concentration alcohol ketone and dibasic acid ester solution is obtained by external discharge.

[0021] Further description is given below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a connection diagram of the device of the utility model;

[0023] Figure 2 It is a connection diagram of the reaction system of the device of the utility model;

[0024] Figure 3 It is a connection diagram of the tail gas treatment system of the utility model device.

[0025] In the accompanying drawings, 1 is a reaction system, 11 is a reactor, 111 is a first feed port, 112 is an overflow port, 113 is a second exhaust port, 12 is a washing chamber, 121 is a second feed port, 122 is a first exhaust port, 13 is an oxygen source distributor, 2 is an exhaust gas treatment system, 21 is a first washing tower, 211 is a first air inlet, 212 is a first washing liquid inlet, 22 is a second washing tower, 221 is a second air inlet, 222 is a second washing liquid inlet, 23 is a third washing tower, 231 is a liquid outlet, 232 is a third air inlet, 233 is a third washing liquid inlet, 3 is a distillation system, 31 is a desalted water pipe, and 4 is a buffer tank. DETAILED DESCRIPTION

[0026] In the utility model, the raw material used is 99.8% cyclohexane.

[0027] Example 1

[0028] See also Figures 1 to 3The device for one-step oxidation of cyclohexane to produce alcohol ketone dibasic acid ester comprises a reaction system 1 and an exhaust gas treatment system 2. The reaction system 1 comprises six reactors 11, each of which is provided with a washing chamber 12 at the top and an oxygen source distributor 13 at the bottom, and each of the oxygen source distributors is connected to a compressed air source. A first feed port 111 is provided at the bottom of each reactor, an overflow port 112 is provided on the side wall, a second feed port 121 is provided in the washing chamber 12, and a first exhaust port 122 is provided on the top. Specifically, the six reactors are connected in series to form a whole, the overflow port of the reactor located upstream is connected to the first feed port of the reactor located downstream, the second feed ports of the six reactors are connected in parallel, and obviously, each first feed port and each second feed port needs to be provided with a valve. In this embodiment, a second exhaust port 113 is also provided on the top of each reactor 11, and the second exhaust port 113 is provided with a valve. In addition, a distillation system 3 is also included. The distillation system usually adopts a multi-stage distillation tower, which is connected in series to form a whole. The liquid inlet end of the distillation system 3 is connected to the overflow port 112 of the reactor located at the downstream end through a buffer tank 4, and each distillation tower in the distillation system is provided with a desalted water pipe 31. The tail gas treatment system 2 includes a first washing tower 21, a second washing tower 22, and a third washing tower 23. Each washing tower is a packed tower, and the number of the first washing tower is one, the number of the second washing tower is one, and the number of the third washing tower is two. The two third washing towers are connected in series to form a whole. The bottoms of the first washing tower and the second washing tower are both provided with washing liquid circulation pipelines, and obviously, the washing liquid circulation pipelines are provided with circulation pumps. A first air inlet 211 is arranged at the lower part of the side wall of the first washing tower 21, and a first washing liquid inlet 212 is arranged at the upper part of the side wall; a second air inlet 221 is arranged at the lower part of the side wall of the second washing tower 22, and a second washing liquid inlet 222 is arranged at the upper part of the side wall; a liquid outlet 231 is arranged at the bottom of the third washing tower 23, a third air inlet 232 is arranged at the lower part of the side wall, and a third washing liquid inlet 233 is arranged at the upper part of the side wall. Obviously, the liquid outlet of the first third washing tower is connected to the third washing liquid inlet of the second third washing tower through a pipeline, and the third washing liquid inlet of the first third washing tower is connected to the cyclohexane source, the liquid outlet of the second third washing tower is connected in parallel with the second feed port 121 of each reactor, and is connected to the first feed port 111 of the reactor at the upstream end, the third air inlet 232 of the second third washing tower is connected in parallel with the first exhaust port 122 and the second exhaust port 113 of each reactor, and the third air inlet of the first third washing tower is connected to the top of the second third washing tower through a pipeline.The first air inlet 211 of the first washing tower 21 is connected to the top of the first third washing tower 23 through a pipeline, the first washing liquid inlet 212 is connected to the desalted water source and the liquid alkali source, the second air inlet 221 of the second washing tower is connected to the top of the first washing tower 21 through a pipeline, and the second washing liquid inlet 222 is connected to the alcohol ketone source. Furthermore, the first washing tower 21, the second washing tower 22, and the third washing tower 23 are all packed towers, each air inlet is located below the corresponding washing tower packing, and each washing liquid inlet is located above the corresponding washing tower packing.

[0029] Example 2

[0030] The device of Example 1 is used to synthesize alcohol ketone dibasic ester:

[0031] Cyclohexane 300m 3 / h, porphyrin cobalt catalyst 0.5kg / h, first added to the third washing tower, then into the 1# oxidation kettle and maintain the flow ratio of the two feed ports at 25:1, 6 oxidation kettles are connected in series, overflowing from 1# to 6# oxidation kettle in turn, each oxidation reactor is allocated a certain amount of air, the total amount of air is 25000Nm 3 / h, pressure 1.0Mpa, cyclohexane and air undergo low-temperature oxidation reaction under the action of catalyst, the reactor temperature is controlled at 140-146°C, the oxidized liquid after the cyclohexane oxidation reaction is washed with water, and then refined by alkane distillation to obtain the product of alcohol ketone dibasic acid ester.

[0032] After testing, the obtained products contain 0.00075% cyclohexane, 27.52% cyclohexanol, 19.35% cyclohexanone, 25.34% dibasic acid, 9.58% ester and 18.21% water. This process does not require the addition of alkali for decomposition reaction, the conversion rate of raw material cyclohexane is close to 100%, and the acid and ester are effectively utilized, which greatly improves the carbon utilization rate.

[0033] The gas phase port of each oxidation reactor is connected to the tail gas washing tower, and the cyclohexane at 135°C in the direct heat exchange tower is used to spray and wash the oxidized tail gas in the tail gas washing tower. The feed volume is 10m 3 / h, the operating pressure of the tail gas washing tower is 3-10bar, the raw oxidation tail gas is spray washed, and the ketones, alcohols, acids, esters and other substances that are easy to produce slagging in the oxidation tail gas are washed away to the greatest extent and returned to the oxidation kettle, preventing ketones, alcohols, acids, esters and other substances from forming slagging on the oxidation tail gas pipeline. The oxidation tail gas flows smoothly in the oxidation tail gas pipeline, thereby achieving the purpose of washing and purifying the oxidation tail gas.

[0034] The applicant has verified through experiments that the annual operation cycle of the device of the utility model is increased from 6500 hours of the traditional oxidation device to 7220 hours.

Claims

1. A device for one-step oxidation of cyclohexane to produce alcohol ketone dibasic acid esters, characterized in that: It comprises a reaction system (1), an exhaust gas treatment system (2), The reaction system (1) comprises at least one reactor (11), wherein a washing chamber (12) is arranged at the top of the reactor (11), an oxygen source distributor (13) is arranged at the bottom, a first feed inlet (111) is arranged at the bottom of the reactor, an overflow port (112) is arranged at the side wall, a second feed inlet (121) is arranged in the washing chamber (12), and a first exhaust port (122) is arranged at the top, The tail gas treatment system (2) comprises a first washing tower (21) and a second washing tower (22), wherein a washing liquid circulation pipeline is arranged at the bottom of each washing tower, a first air inlet (211) is arranged at the lower part of the side wall of the first washing tower (21), and a first washing liquid inlet (212) is arranged at the upper part of the side wall, and a second air inlet (221) is arranged at the lower part of the side wall of the second washing tower (22), and a second washing liquid inlet (222) is arranged at the upper part of the side wall, The first feed port (111) and the second feed port (121) of the reaction system are both connected to a cyclohexane source, the first exhaust port (122) is connected to a first air inlet (211) of a tail gas treatment system, the first washing liquid inlet (212) of the tail gas treatment system is connected to a desalted water source and a liquid alkali source, the second air inlet (221) is connected to the top of a first washing tower (21) through a pipeline, and the second washing liquid inlet (222) is connected to an alcohol ketone source.

2. The device for producing alcohol-ketone dibasic acid ester by one-step oxidation of cyclohexane according to claim 1, characterized in that: The invention also comprises a third washing tower (23), wherein a liquid outlet (231) is arranged at the bottom of the third washing tower (23), a third air inlet (232) is arranged at the lower part of the side wall, and a third washing liquid inlet (233) is arranged at the upper part of the side wall, the liquid outlet (231) is connected to the first feed inlet (111) and the second feed inlet (121) of the reaction system, the third air inlet (232) is connected to the first exhaust port (122) of the reactor, the first air inlet (211) of the first washing tower (21) is connected to the top of the third washing tower (23) through a pipeline, and the third washing liquid inlet (233) is connected to a cyclohexane source.

3. The device for producing alcohol ketone dibasic acid ester by one-step oxidation of cyclohexane according to claim 2, characterized in that: The number of the third washing towers (23) is two, which are connected in series to form a whole, and the oxygen source distributor (13) is connected to a compressed air source and / or a compressed oxygen source.

4. The device for producing alcohol ketone dibasic acid ester by one-step oxidation of cyclohexane according to claim 2 or 3, characterized in that: The first washing tower (21), the second washing tower (22) and the third washing tower (23) are all packed towers, each air inlet is located below the packing of the corresponding washing tower, and each washing liquid inlet is located above the packing of the corresponding washing tower.

5. The device for producing alcohol ketone dibasic acid ester by one-step oxidation of cyclohexane according to any one of claims 1 to 3, characterized in that: The top of the reactor (11) is provided with a second exhaust port (113), and the second exhaust port (113) is provided with a valve, and is connected to the air inlet of the washing tower in parallel with the first exhaust port.

6. The device for producing alcohol ketone dibasic acid ester by one-step oxidation of cyclohexane according to any one of claims 1 to 3, characterized in that: The number of the reactors (11) is multiple and they are connected in series to form a whole. The overflow port of the upstream reactor is connected to the first feed port of the downstream reactor, and the second feed ports of each reactor are connected in parallel.

7. The device for producing alcohol ketone dibasic acid ester by one-step oxidation of cyclohexane according to any one of claims 1 to 3, characterized in that: It also includes a distillation system (3), the liquid inlet end of the distillation system (3) is connected to the overflow port (112) of the reactor through a buffer tank (4), and the distillation system is provided with a desalted water pipe (31).

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