CN218422766U - Benzene hydrogenation circulating benzene washing and purifying system - Google Patents
Benzene hydrogenation circulating benzene washing and purifying system Download PDFInfo
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- CN218422766U CN218422766U CN202222257354.7U CN202222257354U CN218422766U CN 218422766 U CN218422766 U CN 218422766U CN 202222257354 U CN202222257354 U CN 202222257354U CN 218422766 U CN218422766 U CN 218422766U
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Abstract
The utility model provides a benzene hydrogenation circulation benzene washing clean system, enters into the recovery benzene scrubbing tower through circulation benzene inlet pipe, sends into the recovery benzene scrubbing tower through the desalinized water wash pipe of recovery benzene scrubbing tower upper end with the desalinized water in the desalinized water pipe network for purify the DMAC that smugglies secretly in the circulation benzene. And the purified recycle benzene is input into the benzene feeding groove again through the recycle benzene discharging pipe to realize recycling. The characteristic that DMAC is easily soluble in water and benzene is not soluble in water is utilized to realize the washing and purification of the recycled benzene, and the DMAC is carried by the recycled benzene to be reduced to zero, so that the conversion rate of benzene hydrogenation is improved. The influence of DMAC on the hydrogenation catalyst is avoided, the economic benefit is improved, and the dynamic balance in the hydrogenation reaction system is stabilized.
Description
Technical Field
The utility model relates to a cyclohexanol production technical field, concretely relates to benzene hydrogenation circulating benzene washing clean system.
Background
In the benzene hydrogenation reaction, raw material hydrogen is compressed and pressurized in a hydrogen compressor, and the compressed hydrogen is sent to the bottoms of the first hydrogenation reactor and the second hydrogenation reactor. Under the action of the hydrogenation catalyst, benzene and hydrogen are partially hydrogenated to generate cyclohexene, and a by-product cyclohexane is generated at the same time. The raw material benzene, the product cyclohexene and the byproduct cyclohexane which cannot be completely converted and a small amount of hydrogen are subjected to flash degassing in a flash tank, and the degassed oil phase (benzene, cyclohexene and cyclohexane) is sent to an extraction and rectification section. Because the boiling points of benzene, cyclohexene and cyclohexane are very close, the separation and purification effect cannot be achieved by a conventional rectification mode, DMAC is generally used as an extracting agent at present, and three materials are extracted and separated according to different solubilities of the benzene, cyclohexene and cyclohexane in the DMAC under different temperature and pressure. After crude cyclohexene enters a debenzolization tower, raw material benzene is preferentially extracted to a tower kettle by DMAC (dimethylacetamide) at the tower top, unextracted cyclohexene, cyclohexane and other components are condensed by a tower top condenser as light components and then enter a debenzolization tower reflux tank, part of the components in the reflux tank are refluxed, and part of the components are externally extracted to a cyclohexene separation tower to separate the cyclohexene and the cyclohexane; conveying the liquid phase in the benzene removal tower kettle to a benzene recovery tower through a power pump for separating benzene and DMAC, wherein the benzene serving as a raw material is gathered at the top of the tower as a light component and condensed into a liquid phase through a tower top condenser and enters a benzene recovery tower reflux tank because the difference between the boiling points of the benzene and the DMAC is large; DMAC is taken as an extractant and is conveyed to the top of the debenzolization tower by a power pump for recycling. And (3) conveying the benzene circulated in the reflux tank of the benzene recovery tower to the benzene recovery tower through a power pump part as reflux, and allowing part of the benzene to enter a benzene feeding groove of a hydrogenation system for recycling as a raw material. However, because the DMAC is an alkaline substance, trace DMAC can return to the benzene feeding groove along with the circulating benzene in the rectification process and further enter a hydrogenation reactor system, so that the activity factor of the catalyst is indirectly influenced, and the activity of the hydrogenation catalyst is reduced. Because the internal balance system of the hydrogenation reactor is weakly acidic, the addition of DMAC disturbs the balance state of the catalyst system. In order to maintain the weakly acidic environment of the benzene hydrogenation system, sulfuric acid is further added to lower the pH of the system. However, the entrainment of DMAC (dimethylacetamide) cannot be calculated, the types of materials in a hydrogenation reactor are more, the effective volume of the reactor is larger, the adjustment by adding sulfuric acid has certain hysteresis, the dynamic balance in the system is broken, a new balance system is difficult to form in a short period, if the DMAC is seriously entrained, the conversion rate and selectivity of a hydrogenation system fluctuate, the yield of cyclohexene is influenced, and the investment cost is increased.
Disclosure of Invention
The utility model discloses an overcome not enough of above technique, provide one kind and avoided the DMAC to the influence of hydrogenation catalyst, improve economic benefits's benzene hydrogenation circulation benzene washing clean system.
The utility model discloses overcome the technical scheme that its technical problem adopted and be:
a benzene hydrogenation recycle benzene scrubbing purification system comprises:
the inlet end of the desulfurization reactor is connected with the benzene feeding pipeline;
a benzene feed tank, the first inlet end of which is connected to the outlet end of the desulfurization reactor;
the inlet end of the hydrogenation reactor is connected with the outlet end of the benzene feeding groove;
the inlet end of the slurry separation tank is connected with the outlet end of the hydrogenation reactor;
the inlet end of the flash tank is connected with the outlet end of the slurry separation tank;
the inlet end of the dehydration tower is connected with the outlet end of the flash tank;
the inlet end of the debenzolization tower is connected with the outlet end of the dehydration tower;
the inlet end of the benzene recovery tower is connected with the outlet end of the debenzolization tower; and
retrieve benzene scrubbing tower, its lower extreme is provided with the circulation benzene inlet pipe, the circulation benzene inlet pipe is connected in the exit end of benzene recovery tower, and the upper end of retrieving benzene scrubbing tower is provided with the desalinized water flushing pipe, desalinized water flushing pipe connects in the desalination water pipeline, retrieves benzene scrubbing tower upper end and is provided with the circulation benzene discharging pipe, the second entry end in benzene feed chute is connected to the circulation benzene discharging pipe.
Furthermore, the lower end of the benzene recovery washing tower is connected with a pressure relief emptying port through a valve, and a water phase discharging pipe is connected to the pressure relief emptying port.
In order to display the liquid level, a liquid level meter is arranged on the recovered benzene washing tower and is positioned at the upper end of the circulating benzene discharge pipe.
In order to facilitate the observation of the change of the interface level, the recovered benzene washing tower is provided with an interface level meter which is arranged between the circulating benzene discharging pipe and the liquid level meter.
In order to realize nitrogen replacement and protection, the top of the recovered benzene washing tower is connected with a nitrogen pipe.
In order to judge the pressure conveniently, a pressure detection device is arranged at the top of the recovered benzene washing tower.
In order to realize the combustion of waste gas, the top of the recovered benzene washing tower is provided with a flare torch pipe.
The beneficial effects of the utility model are that: and the desalted water in the desalted water pipe network is sent into the recovered benzene washing tower through a desalted water flushing pipe at the upper end of the recovered benzene washing tower, and the desalted water is used for purifying DMAC (dimethyl acetamide) carried in the recycled benzene. And the purified recycle benzene is input into the benzene feeding groove again through the recycle benzene discharging pipe to realize recycling. The characteristic that DMAC is easily soluble in water and benzene is not soluble in water is utilized, the washing and purification of the recycled benzene are realized, the DMAC is carried by the recycled benzene to be reduced to zero, and the conversion rate of benzene hydrogenation is improved. The influence of DMAC on the hydrogenation catalyst is avoided, the economic benefit is improved, and the dynamic balance in the hydrogenation reaction system is stabilized.
Drawings
FIG. 1 is a schematic structural view of a washing tower for recovering benzene according to the present invention;
FIG. 2 is a schematic structural view of the present invention;
in the figure, 1, a desulfurization reactor 2, a benzene feed tank 3, a hydrogenation reactor 4, a slurry separation tank 5, a flash tank 6, a dehydration tower 7, a debenzolization tower 8, a benzene recovery tower 9, a recovered benzene washing tower 91, a recycled benzene feed pipe 92, a recycled benzene discharge pipe 93, a desalted water washing pipe 94, a nitrogen pipe 95, a water phase discharge pipe 96, a pressure detection device 97, a pressure relief purge port 98, a flare pipe 99, a liquid level meter 910 and a boundary level meter are arranged.
Detailed Description
The present invention will be further explained with reference to fig. 1 and 2.
A benzene hydrogenation cycle benzene scrubbing purification system comprising: the inlet end of the desulfurization reactor 1 is connected with a benzene feeding pipeline; a benzene feed tank 2, the first inlet end of which is connected to the outlet end of the desulfurization reactor 1; a hydrogenation reactor 3, the inlet end of which is connected with the outlet end of the benzene feeding groove 2; a slurry separation tank 4, the inlet end of which is connected to the outlet end of the hydrogenation reactor 3; a flash tank 5, the inlet end of which is connected to the outlet end of the slurry separation tank 4; a dehydration tower 6, the inlet end of which is connected to the outlet end of the flash tank 5; a debenzolization tower 7, the inlet end of which is connected to the outlet end of the dehydration tower 6; a benzene recovery column 8, the inlet end of which is connected to the outlet end of the debenzolization column 7; and a recycled benzene washing tower 9, the lower end of which is provided with a recycled benzene feeding pipe 91, the recycled benzene feeding pipe 91 is connected to the outlet end of the benzene recycling tower 8, the upper end of the recycled benzene washing tower 9 is provided with a desalted water flushing pipe 93, the desalted water flushing pipe 93 is connected to a desalted water pipeline, the upper end of the recycled benzene washing tower 9 is provided with a recycled benzene discharging pipe 92, and the recycled benzene discharging pipe 92 is connected to the second inlet end of the benzene feeding tank 2.
Further, a liquid level meter 99 is arranged on the recovered benzene washing tower 9, and the liquid level meter 99 is positioned at the upper end of the circulating benzene discharge pipe 92. The liquid level change of the recycle benzene in the whole recycle benzene washing tower 9 can be conveniently observed by the liquid level meter 99. Fresh benzene enters a desulfurization reactor 1 to be desulfurized and then enters a benzene feeding tank 2, the desulfurized benzene enters a hydrogenation reactor 3, under the action of a hydrogenation catalyst, the benzene and hydrogen are partially hydrogenated to generate cyclohexene, a byproduct cyclohexane is generated, and the raw material benzene which cannot be completely converted, the product cyclohexene, the byproduct cyclohexane and a small amount of hydrogen carried in the benzene are subjected to flash evaporation and degassing in a flash tank 5. The degassed oil phase (benzene, cyclohexene and cyclohexane) is sent to a dehydration tower 6 to be dehydrated and then enters a debenzolization tower 7, the raw material benzene is preferentially extracted to a tower kettle by DMAC (dimethyl acetamide) at the tower top, unextracted cyclohexene, cyclohexane and other components are condensed as light components by a tower top condenser and then enter a benzene recovery tower 8, and then enter a recovered benzene washing tower 9 through a recycled benzene feeding pipe 91, and desalted water in a desalted water pipe network is sent to the recovered benzene washing tower 9 through a desalted water flushing pipe 93 at the upper end of the recovered benzene washing tower 9 and is used for purifying the DMAC carried in the recycled benzene. The purified recycle benzene is fed into the benzene feed tank 2 again through the recycle benzene discharge pipe 92 to be recycled. The characteristic that DMAC is easily soluble in water and benzene is not soluble in water is utilized, the washing and purification of the recycled benzene are realized, the DMAC is carried in the recycled benzene and is reduced to zero, the conversion rate of benzene hydrogenation is improved by 2 percent, and the selectivity is improved by 3 percent. The influence of DMAC on the hydrogenation catalyst is avoided, the economic benefit is improved, and the dynamic balance in the hydrogenation reaction system is stabilized. Due to the high cost of the hydrogenation catalyst, the cost increase caused by the inactivation of the effective catalyst is avoided to a certain extent by adopting the equipment.
Further, a boundary level meter 910 is arranged on the recovered benzene washing tower 9, and the boundary level meter 910 is arranged between the recycled benzene discharging pipe 92 and the liquid level meter 99. The boundary position change condition can be conveniently observed through the boundary position meter 910, and the water consumption for washing can be adjusted in time.
Further, a nitrogen gas pipe 94 is connected to the top of the recovered benzene washing column 9. Nitrogen access may be provided through a nitrogen line 94 to provide nitrogen substitution and protection when the apparatus is deactivated.
Further, a pressure detecting device 96 is installed at the top of the recovered benzene washing tower 9. The pressure of the whole equipment can be conveniently observed through the pressure detection device 96, the lower end of the recovered benzene washing tower 9 is connected with a pressure relief emptying port 97 through a valve, and the pressure relief emptying port 97 is connected with a water phase discharging pipe 95. Pressure is relieved through the pressure relief purge port 97 when the device is deactivated or needs to be opened. An aqueous phase outlet conduit 95 allows the aqueous phase containing the DMAC to be discharged to a recovery header.
Further, a flare tube 98 is installed at the top of the recovered benzene washing tower 9. The flare tube 98 can burn the exhaust gas in the recovered benzene washing tower 9 to prevent air pollution.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described above, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. A benzene hydrogenation circulating benzene washing and purifying system is characterized by comprising:
the inlet end of the desulfurization reactor (1) is connected with a benzene feeding pipeline;
a benzene feeding groove (2), the first inlet end of which is connected with the outlet end of the desulfurization reactor (1);
the inlet end of the hydrogenation reactor (3) is connected with the outlet end of the benzene feeding tank (2);
the inlet end of the slurry separation tank (4) is connected with the outlet end of the hydrogenation reactor (3);
a flash tank (5) with an inlet end connected to the outlet end of the slurry separation tank (4);
a dehydration tower (6) with an inlet end connected to the outlet end of the flash tank (5);
a debenzolization tower (7) the inlet end of which is connected to the outlet end of the dehydration tower (6);
a benzene recovery tower (8), the inlet end of which is connected with the outlet end of the debenzolization tower (7); and
retrieve benzene wash tower (9), its lower extreme is provided with circulation benzene inlet pipe (91), circulation benzene inlet pipe (91) is connected in the exit end of benzene recovery tower (8), and the upper end of retrieving benzene wash tower (9) is provided with desalted water flushing pipe (93), desalted water flushing pipe (93) are connected in the desalination water pipeline, and recovery benzene wash tower (9) upper end is provided with circulation benzene discharging pipe (92), circulation benzene discharging pipe (92) are connected in the second entry end of benzene feed chute (2).
2. The benzene hydrorefining recycle benzene scrubbing purification system of claim 1, wherein: the lower end of the recovered benzene washing tower (9) is connected with a pressure relief and purge opening (97) through a valve, and the pressure relief and purge opening (97) is connected with a water phase discharge pipe (95).
3. The benzene hydrorefining recycle benzene scrubbing purification system of claim 1, wherein: a liquid level meter (99) is arranged on the recovered benzene washing tower (9), and the liquid level meter (99) is positioned at the upper end of the circulating benzene discharge pipe (92).
4. The benzene hydrorefining recycle benzene scrubbing purification system of claim 1, wherein: the recycled benzene washing tower (9) is provided with a level meter (910), and the level meter (910) is arranged between the recycled benzene discharging pipe (92) and the liquid level meter (99).
5. The benzene hydrorefining recycle benzene scrubbing purification system of claim 1, wherein: the top of the recovered benzene washing tower (9) is connected with a nitrogen pipe (94).
6. The benzene hydrorefining recycle benzene scrubbing purification system of claim 1, wherein: and a pressure detection device (96) is arranged at the top of the recovered benzene washing tower (9).
7. The benzene hydrorefining recycle benzene scrubbing purification system of claim 1, wherein: and a flare torch pipe (98) is arranged at the top of the recovered benzene washing tower (9).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222257354.7U CN218422766U (en) | 2022-08-26 | 2022-08-26 | Benzene hydrogenation circulating benzene washing and purifying system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222257354.7U CN218422766U (en) | 2022-08-26 | 2022-08-26 | Benzene hydrogenation circulating benzene washing and purifying system |
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| Publication Number | Publication Date |
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| CN218422766U true CN218422766U (en) | 2023-02-03 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202222257354.7U Active CN218422766U (en) | 2022-08-26 | 2022-08-26 | Benzene hydrogenation circulating benzene washing and purifying system |
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| CN (1) | CN218422766U (en) |
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- 2022-08-26 CN CN202222257354.7U patent/CN218422766U/en active Active
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