Method and device for recovering toluene containing tctnb by forced circulation in a vacuum batch rectification column

Abstract

The present application relates to a method and device for recovering toluene containing TCTNB by vacuum intermittent rectification kettle forced circulation, feeding the material to be purified into the intermittent rectification tower through a feeding pipeline, controlling the vacuum degree of the intermittent rectification tower to achieve the effect of vacuum, heating the kettle by a reboiler, and heating the kettle liquid by a non-forced circulation pipeline to make the rectification tower produce full reflux, setting the reflux ratio of the top of the rectification tower to make toluene be extracted through an extraction pipeline, switching the forced circulation pipeline when the kettle liquid reaches before saturation, setting a Y-type filter in the forced circulation pipeline, starting the circulating pump to make the kettle reboiler be forced circulation type, stopping the extraction of toluene at the top when the kettle liquid reaches saturation and small solid particles are suspended and precipitated. The present application has the advantages of reasonable design, simple structure, convenient operation, effective prevention of pipeline blockage, reduction of reboiler fouling, reduction of the operating temperature of energy-containing material and solvent separation, and improvement of toluene recovery rate.

Description

Technical Field

[0001] This invention relates to a solvent toluene recovery technology in the production process of energetic material TCTNB, specifically to a method for recovering toluene, the solvent of energetic material TCTNB, by means of vacuum intermittent distillation and forced circulation of the distillation column bottom, belonging to the field of separation technology; specifically, it is a method and apparatus for recovering toluene containing TCTNB by forced circulation of the distillation column bottom. Background Technology

[0002] 1,3,5-Trichloro-2,4,6-trinitrobenzene (TCTNB) is a byproduct of the production of triaminotrinitrobenzene (TATB). Both TCTNB and TATB are energetic materials and pose certain hazards. To separate the energetic material TCTNB from the solvent toluene, the toluene solution containing TCTNB needs to be purified by forced circulation in the reboiler of a vacuum intermittent distillation unit.

[0003] Existing technologies, such as patent CN203469519U, describe a distillation column circulation system for intermittent forced convection to solve coking of light fractions in the reboiler. This circulation system includes: a separation column, a reboiler-to-separation column pipeline, a reboiler, a separation column-to-reboiler pipeline, a circulation pump, a control system, and a material outlet at the bottom of the separation column. This separation employs non-continuous forced circulation, which reduces the self-polymerization and polymerization of light fractions in the reboiler of the separation column for separating the C5 fraction. Another example is patent CN212491617U, which describes an external forced circulation distillation vessel system. This distillation vessel body has a liquid accumulation circulation component located below it, which includes components connected to the bottom of the distillation vessel body. One end of the liquid extraction pipe is connected to the other end, which is inserted through the inlet end of the upper side of the filter tank. The filter tank is equipped with a filter screen. After the filter screen intercepts the reaction waste, the relatively pure liquid is added back to the distillation kettle body through the liquid inlet pipe, so as to maximize the utilization of the liquid, save reaction raw materials, and thus save costs. For example, patent CN117018650A introduces a low-temperature continuous recovery method for high-boiling-point solvents containing explosives. It recovers high-boiling-point solvents containing explosives through short-path / molecular distillation technology. The implementation example includes the recovery of a toluene solution containing 1% TCTNB through molecular distillation, with a toluene recovery rate of 85%.

[0004] Since TCTNB is an energetic material, directly recovering the solvent toluene containing TCTNB through forced circulation in the bottom of an atmospheric pressure batch distillation column would result in excessively high temperatures in the bottom of the column during separation, posing a certain risk. Therefore, separation must be carried out under reduced pressure, but currently there is no separation technology that uses forced circulation in the bottom of a reduced-pressure batch distillation column. The molecular distillation technology currently used to recover toluene solutions containing TCTNB has a complex equipment structure, high equipment cost, and can only separate toluene solutions with low concentrations of energetic materials. For toluene solutions with high concentrations of energetic materials, problems such as solid particle precipitation clogging the device and low solvent recovery rates may occur.

[0005] If a vacuum intermittent distillation column is used to force the circulation of toluene solution containing energetic materials, the technology is mature, the equipment structure is simple, the equipment cost is low, and a high recovery rate can be achieved for both high-concentration and low-concentration toluene solutions. Summary of the Invention

[0006] This invention addresses the problem of separating and purifying the energetic material TCTNB from the solvent toluene. Since TCTNB is an energetic material, the high temperature at the bottom of the distillation column during atmospheric distillation poses a certain risk. Therefore, toluene containing TCTNB is recovered through vacuum intermittent distillation. As the toluene recovery rate from the top of the vacuum intermittent distillation column increases, the concentration of heavy components in the bottom material gradually increases. When a saturated solution is formed, small solid particles precipitate, causing blockage of pipelines and scaling in the reboiler. Therefore, a forced circulation method using the reboiler is employed to purify toluene. The distillation column bottom is designed with a conical head, allowing the centrifugal force generated by the high-speed rotation of the circulating liquid to separate the solid particles from the liquid. A Y-type filter is installed in the forced circulation pipeline to filter out any solid particles that may precipitate when the bottom liquid reaches saturation. Through the above invention, the blockage of pipelines by solid particles is prevented, reboiler scaling is reduced, the bottom temperature is lowered, the safety of the equipment is ensured, and a high recovery rate can be achieved for both high and low concentrations of toluene solutions.

[0007] The technical solution of the present invention is as follows:

[0008] The method for recovering TCTNB-containing compounds by forced circulation in the reboiler of a vacuum batch distillation column includes the following steps:

[0009] (1) Add the material to be purified into the batch distillation column through the feed pipeline;

[0010] (2) Control the vacuum level of the batch distillation column to achieve the effect of pressure reduction;

[0011] (3) The column bottom is heated by reboiler, and the column bottom liquid is heated by non-forced circulation pipeline to generate total reflux in the distillation column. The reflux ratio at the top of the distillation column is set so that toluene is collected through the collection pipeline.

[0012] (4) Before the liquid in the bottom of the column reaches saturation, switch the forced circulation pipeline and start the circulation pump to make the reboiler in the bottom of the column a forced circulation type;

[0013] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the liquid in the bottom of the column is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the amount of toluene collected from the top of the column is the toluene yield.

[0014] In step (2), the vacuum level of the batch distillation column is controlled to be 35-55 kPa.

[0015] The preferred toluene yield from the top of the tower during step (4) of switching the forced circulation pipeline is 50-65%.

[0016] In step (5), the toluene yield from the top of the tower can reach 90% to 93%.

[0017] The present invention relates to an apparatus for the forced circulation recovery of TCTNB-containing materials from the bottom of a vacuum intermittent distillation column; the apparatus includes an intermittent distillation column, a condenser, a Y-type filter, a reboiler, and a circulation pump; the bottom of the distillation column is provided with a forced circulation pipeline containing the circulation pump and a non-forced circulation pipeline without the circulation pump; the forced circulation pipeline is equipped with a Y-type filter.

[0018] The device described above is forcibly recycled from the reboiler of a vacuum intermittent distillation column to recover TCTNB; the reboiler of the distillation column is designed in the form of a conical head, with a cone shell half-apex angle α of 30 to 45°.

[0019] The device described above is forcibly recycled from the bottom of a vacuum intermittent distillation column to recover TCTNB. The distillation column bottom structure includes a bottom liquid circulation outlet, a bottom liquid circulation inlet, and a waste pipeline. The bottom liquid circulation outlet is located on the side of a conical head, and the ratio of the height of the bottom liquid circulation inlet pipe to the height of the conical head is 0.1 to 0.2.

[0020] The device described above recovers TCTNB-containing material through forced circulation in the reboiler of a vacuum intermittent distillation column; a forced circulation pipeline is set up on two pipelines containing circulation pumps in the reboiler of the distillation column.

[0021] The specific explanation is as follows:

[0022] The materials to be separated in this invention are byproducts and solvent toluene produced during the production of triaminotrinitrobenzene (TATB). The composition of the materials to be separated includes: solvent toluene, 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB), water, and other related byproducts.

[0023] In step (5) of the method, the toluene yield from the top of the tower can reach 90% to 93%.

[0024] The method described above can be used to purify toluene to obtain high-purity toluene, which has the following composition: toluene ≥ 99.8 wt% and water ≤ 0.01 wt%.

[0025] The device of the present invention, such as Figure 1 , Figure 2 As shown: including batch distillation column (1), condenser (2), valve (3), pre-shutdown valve (4), Y-type filter (5), reboiler (6), post-shutdown valve (7), circulation pump (8), waste liquid discharge valve (9), distillation column bottom conical head structure (10), feed line (a), waste line (b), toluene collection line (c), heating steam line (d), condensate line (e), non-forced circulation line (f), forced circulation line (g), bottom liquid circulation outlet (h), bottom liquid circulation inlet (i).

[0026] The batch distillation unit is fed into the batch distillation column (1) through the feed line (a). The top of the column is collected through the toluene collection line (c). The top vapor is condensed through the condenser (2). The bottom material is heated through the reboiler (6). The bottom waste is discharged through the waste line (b).

[0027] Y-type filters are inexpensive, simple in structure, and easy to install, remove and clean. Two sets of Y-type filters are installed in parallel with the circulating pump, respectively on two forced circulation pipelines (f). The two sets of Y-type filters (5) are equipped with a shut-off valve (4) before shut-off and a shut-off valve (7) after shut-off. The filter screen in the Y-type filter cartridge has a mesh size of 50 to 80 mesh. The filter filters the small solid particles that are about to be saturated and precipitated in the batch distillation tower, thereby preventing them from entering the circulating pump and heat exchanger, preventing pipeline blockage and scaling, increasing the service life of the equipment, and reducing the cleaning cycle of pipelines and filters.

[0028] This device recovers TCTNB-containing substances through forced circulation in the reboiler of a vacuum intermittent distillation column. The reboiler is designed with a conical head, with a cone angle α between 30° and 45°. The reboiler structure includes: a reboiler liquid circulation outlet, a reboiler liquid circulation inlet, and a waste pipe. The reboiler liquid circulation outlet is located on the side of the conical head, and the ratio of the reboiler liquid circulation inlet pipe height (H2) to the conical head height (H1) is between 0.1 and 0.2.

[0029] The structure of the distillation column reboiler is as follows: Figure 2 As shown, the column includes a column bottom liquid circulation outlet (h), a column bottom liquid circulation inlet (i), and a waste pipe (b). The column bottom liquid circulation outlet (h) is not located at the bottom of the distillation column bottom to prevent the continuous circulation and precipitation of small solid particles. Instead, it is located on the side of the conical head to achieve the effect of circulating only the clear liquid in the upper layer of the column bottom.

[0030] Two forced circulation lines (g) with circulation pumps are set in the bottom of the distillation column, one of which is a backup line. A non-forced circulation line (f) is set in the line without circulation pumps. Two sets of Y-type filters (7) are set in the two forced circulation lines (g), one of which is a backup filter. No Y-type filter is set in the non-forced circulation line (f). Before the liquid in the bottom of the column reaches saturation, the TCTNB concentration in the bottom material is low and no solids will precipitate. The non-forced circulation line (f) is used to heat the material directly through the reboiler (7) to reduce fluid resistance and reduce pump energy consumption. As toluene is gradually collected from the top of the batch distillation column, the toluene yield gradually increases, and the TCTNB concentration in the bottom material increases, which may precipitate small solid particles. The forced circulation line (g) is used to force the bottom material to circulate through the circulation pump (8).

[0031] The device for forced recycling of TCTNB-containing liquids in a vacuum intermittent distillation column reboiler is designed with a conical head. This allows the solid particles in the liquid being recycled back to the reboiler to be separated from the liquid by centrifugal force generated by high-speed rotation.

[0032] The conical head structure (10) of the distillation column bottom can efficiently separate solid particles from liquid in suspension. When the high-speed inflow of the suspension containing solid particles cuts into the bottom liquid circulation inlet (i) on the side of the equipment, a strong rotating flow field is formed in the cavity. The rotation generates a huge centrifugal force, which throws the denser solid particles toward the wall and moves spirally downward along the wall, accumulating at the bottom of the bottom. Meanwhile, the less dense liquid accumulates toward the center and is recirculated and heated from the bottom liquid circulation outlet (h). This achieves the effect of circulating only the clear liquid and not circulating small solid particles, thus reducing pipe blockage.

[0033] A method for recovering TCTNB-containing compounds via forced circulation in the reboiler of a vacuum batch distillation column is characterized by comprising the following steps:

[0034] The operation steps of this invention are as follows:

[0035] (1) The material to be purified is added to the batch distillation column (1) through the feed line (a);

[0036] (2) Control the vacuum level of the batch distillation column to achieve the effect of pressure reduction;

[0037] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, set the reflux ratio at the top of the distillation column, and collect toluene through toluene collection pipeline (c);

[0038] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0039] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the liquid in the bottom of the column is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the amount of toluene collected from the top of the column is the toluene yield.

[0040] To reduce the operating temperature of batch distillation and improve the safety of separation and purification operations, a forced circulation method is adopted in the bottom of a vacuum batch distillation column to separate the energetic material TCTNB from the solvent toluene. The liquid level of the material to be purified is added to the batch distillation column at 60-75%, the vacuum degree of the device is set to 35-55 kPa, and the reflux ratio at the top of the column is set to 1-2.5.

[0041] The materials to be separated are byproducts and solvent toluene produced during the production of triaminotrinitrobenzene (TATB). The composition of the materials to be separated includes: solvent toluene, 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB), water, and other related byproducts.

[0042] The composition of the material collected from the top of the tower after separation and purification is: toluene ≥ 99.8 wt%, water ≤ 0.01 wt%.

[0043] This invention provides a method for recovering toluene containing TCTNB through forced circulation in the bottom of a vacuum intermittent distillation column. Before the liquid in the bottom reaches saturation, the TCTNB concentration in the bottom material is low and no solids precipitate. A non-forced circulation pipeline (f) is used to directly heat the material through a reboiler (6), thereby reducing fluid resistance and pump energy consumption. As toluene is gradually collected from the top of the intermittent distillation column, the toluene yield gradually increases, and the TCTNB concentration in the bottom material increases. Small solid particles may precipitate in the bottom. A forced circulation pipeline (g) is used to force circulation of the bottom material through a circulation pump (8). Toluene collection from the top of the column is stopped when small solid particles precipitate in the bottom. In the design of the distillation column bottom, a conical head is used so that the liquid returning to the bottom that may contain small solid particles can be separated from the liquid by the centrifugal force generated by high-speed rotation. A Y-type filter is installed on the forced circulation pipeline to filter out small solid particles that may precipitate when the bottom liquid is about to reach saturation. By controlling the vacuum level of the batch distillation column, the bottom temperature is reduced and the toluene recovery rate is increased, ensuring safety during the purification of solvents containing energetic materials. The toluene yield from the top of the column when switching the forced circulation pipeline is preferably 50-65%. The composition of the material collected from the top of the column after separation and purification includes: toluene ≥ 99.8 wt% and water ≤ 0.01 wt%. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the overall structure of a distillation column for a method of recovering toluene containing TCTNB through forced circulation in the bottom of a vacuum batch distillation column according to the present invention.

[0045] Figure 2 This is a schematic diagram of the conical head structure of the reboiler of a distillation column, which is part of a method for recovering toluene containing TCTNB through forced circulation in the reboiler of a vacuum intermittent distillation column according to the present invention.

[0046] Among them: batch distillation column (1), condenser (2), valve (3), pre-shutdown valve (4), Y-type filter (5), reboiler (6), post-shutdown valve (7), circulating pump (8), waste liquid discharge valve (9), distillation column bottom conical head structure (10), feed pipeline (a), waste pipeline (b), toluene collection pipeline (c), heating steam pipeline (d), condensate pipeline (e), non-forced circulation pipeline (f), forced circulation pipeline (g), bottom liquid circulation outlet (h), bottom liquid circulation inlet (i), cone shell half-apex angle (α), conical head height (H1), bottom liquid circulation inlet pipe height (H2). Detailed Implementation

[0047] The present invention employs the following apparatus:

[0048] like Figure 1 As shown:

[0049] The apparatus includes: a batch distillation column (1), a condenser (2) and a toluene collection line (c) are installed at the top of the batch distillation column (1), the top vapor is condensed by the condenser (2), and a portion of the condensate is collected through the toluene collection line (c); a feed line (a) is installed on the side of the batch distillation column (1), the material to be purified is added to the column for separation through the feed line (a); a bottom liquid circulation outlet (h) and a bottom liquid circulation inlet (i) are installed on the side of the bottom of the batch distillation column (1), the bottom liquid circulation outlet (h) and the bottom liquid circulation inlet (i) are used for the bottom liquid to be circulated and heated; a non-forced circulation line (f) and a forced circulation line (g) are installed on the bottom liquid circulation outlet (h) to switch the circulation mode of the bottom material; a Y-type filter (5), a reboiler (6) and a circulation pump (8) are installed on the forced circulation line (g), and two sets of Y-type filters (7) and Two sets of circulating pumps (8), one of which is a spare pipeline. The spare pipeline is equipped with a spare filter and a circulating pump. The circulating pump (8) is used for forced circulation of the bottom liquid of the tower. The Y-type filter (5) is equipped with a shut-off valve (4) before and after the shut-off valve (7) for starting, stopping and washing the filter. The reboiler (6) is equipped with a heating steam pipeline (d) and a condensate pipeline (e) for heating the bottom liquid of the tower. The non-forced circulation pipeline (f) is equipped with a valve (3) for opening and closing the material of the non-forced circulation pipeline (f). The non-forced circulation pipeline (f) is not equipped with a Y-type filter. The bottom of the batch distillation tower (1) is equipped with a distillation tower bottom conical head structure (10). The distillation tower bottom conical head structure (10) can separate the solid particles in the suspension from the liquid, so that the bottom of the tower only circulates the clear liquid at the top of the tower. The bottom of the batch distillation tower (1) is equipped with a waste pipeline (b) for discharging the waste liquid from the bottom of the tower.

[0050] like Figure 2 As shown:

[0051] The apparatus includes: a distillation column bottom conical head structure (10), on which a waste pipe (b), a bottom liquid circulation outlet (h), and a bottom liquid circulation inlet (i) are provided; the structural parameters of the distillation column bottom conical head structure (10) include the cone shell half-apex angle (α), the cone head height (H1), and the bottom liquid circulation inlet pipe height (H2).

[0052] The operation steps of this invention are as follows:

[0053] (1) The material to be purified is added to the batch distillation column (1) through the feed line (a);

[0054] (2) Control the vacuum level of the batch distillation column to achieve the effect of pressure reduction;

[0055] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, set the reflux ratio at the top of the distillation column, and collect toluene through toluene collection pipeline (c);

[0056] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0057] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the liquid in the bottom of the column is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the amount of toluene collected from the top of the column is the toluene yield.

[0058] To reduce the operating temperature of batch distillation and improve the safety of separation and purification operations, a forced circulation method is adopted in the bottom of the vacuum batch distillation column to separate the energetic material TCTNB from the solvent toluene. The liquid level of the material to be purified is added to the batch distillation column at 60-75%, the vacuum degree of the device is set to 0-80 kPa, and the reflux ratio at the top of the column is set to 1-2.5.

[0059] The composition of the material to be purified includes: 75-90 wt% toluene, 9.8-24.2 wt% 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), 0.2-0.8 wt% 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB), and 0.01 wt% water.

[0060] The distillation column bottom conical head structure (10) is designed as a conical head with a cone shell half-apex angle α of 30 to 45°.

[0061] The bottom liquid circulation outlet of the tower is located on the side of the conical head, and the ratio of the height (H2) of the bottom liquid circulation inlet pipe to the height (H1) of the conical head is between 0.1 and 0.2.

[0062] The preferred toluene yield from the top of the tower when switching the forced circulation pipeline is 50-65%.

[0063] The composition of the material collected from the top of the tower after separation and purification is: toluene ≥ 99.8 wt%, water ≤ 0.01 wt%.

[0064] Example 1

[0065] (1) A material is added to the batch distillation column (1) through the feed line (a), the composition of which is: 75 wt% toluene, 24.2 wt% 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), 0.8 wt% 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB), and 0.01 wt% water;

[0066] (2) Control the batch distillation column (1) to reach a vacuum of 80 kPa;

[0067] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, the reflux ratio is controlled to be 1 to 2.5, and toluene is collected through toluene collection pipeline (c);

[0068] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0069] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the bottom liquid is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the temperature of the bottom of the column is 84°C and the toluene yield is 71%.

[0070] The material level added to the bottom of the tower is 70%; the toluene recovery rate from the top of the tower when switching the forced circulation pipeline is 50%; the half-apex angle α of the conical head shell of the bottom of the tower is 40°; the ratio of the height of the bottom liquid circulation inlet pipe (H2) to the height of the conical head (H1) is 0.15.

[0071] Example 2

[0072] (1) A material is added to the batch distillation column (1) through the feed line (a), the composition of which is: 75 wt% toluene, 24.2 wt% 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), 0.8 wt% 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB), and 0.01 wt% water;

[0073] (2) Control the batch distillation column (1) to reach a vacuum of 55 kPa;

[0074] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, the reflux ratio is controlled to be 1 to 2.5, and toluene is collected through toluene collection pipeline (c);

[0075] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0076] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the liquid in the bottom of the column is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the temperature of the bottom of the column is 110℃ and the toluene yield is 90%.

[0077] The material level added to the bottom of the tower is 70%; the toluene recovery rate from the top of the tower when switching the forced circulation pipeline is 65%; the half-apex angle α of the conical head shell of the bottom of the tower is 40°; the ratio of the height of the bottom liquid circulation inlet pipe (H2) to the height of the conical head (H1) is 0.15.

[0078] Example 3

[0079] (1) A material is added to the batch distillation column (1) through the feed line (a), the composition of which is: 75 wt% toluene, 24.2 wt% 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), 0.8 wt% 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB), and 0.01 wt% water;

[0080] (2) Control the batch distillation column (1) to achieve a vacuum of 35 kPa;

[0081] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, the reflux ratio is controlled to be 1 to 2.5, and toluene is collected through toluene collection pipeline (c);

[0082] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0083] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the bottom liquid is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the temperature of the bottom of the column is 115℃ and the toluene yield is 92%.

[0084] The material level added to the bottom of the tower is 70%; the toluene recovery rate from the top of the tower when switching the forced circulation pipeline is 65%; the half-apex angle α of the conical head shell of the bottom of the tower is 40°; the ratio of the height of the bottom liquid circulation inlet pipe (H2) to the height of the conical head (H1) is 0.15.

[0085] Example 4

[0086] (1) A material is added to the batch distillation column (1) through the feed line (a), the composition of which is: 75 wt% toluene, 24.2 wt% 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), 0.8 wt% 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB), and 0.01 wt% water;

[0087] (2) Control the batch distillation column (1) to reach a vacuum of 0 kPa;

[0088] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, the reflux ratio is controlled to be 1 to 2.5, and toluene is collected through toluene collection pipeline (c);

[0089] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0090] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the bottom liquid is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the temperature of the bottom of the column is 140℃ and the toluene yield is 95%.

[0091] The material level added to the bottom of the tower is 70%; the toluene recovery rate from the top of the tower when switching the forced circulation pipeline is 65%; the half-apex angle α of the conical head shell of the bottom of the tower is 40°; the ratio of the height of the bottom liquid circulation inlet pipe (H2) to the height of the conical head (H1) is 0.15.

[0092] Example 5

[0093] (1) A material is added to the batch distillation column (1) through the feed line (a), the composition of which is: toluene 90 wt%, 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) 9.8 wt%, 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB) 0.2 wt%, and water 0.01 wt%;

[0094] (2) Control the batch distillation column (1) to reach a vacuum of 80 kPa;

[0095] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, the reflux ratio is controlled to be 1 to 2.5, and toluene is collected through toluene collection pipeline (c);

[0096] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0097] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the bottom liquid is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the temperature of the bottom of the column is 71°C and the toluene yield is 76%.

[0098] The material level added to the bottom of the tower is 70%; the toluene recovery rate from the top of the tower when switching the forced circulation pipeline is 50%; the half-apex angle α of the conical head shell of the bottom of the tower is 40°; the ratio of the height of the bottom liquid circulation inlet pipe (H2) to the height of the conical head (H1) is 0.15.

[0099] Example 6

[0100] (1) A material is added to the batch distillation column (1) through the feed line (a), the composition of which is: toluene 90 wt%, 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) 9.8 wt%, 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB) 0.2 wt%, and water 0.01 wt%;

[0101] (2) Control the batch distillation column (1) to reach a vacuum of 55 kPa;

[0102] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, the reflux ratio is controlled to be 1 to 2.5, and toluene is collected through toluene collection pipeline (c);

[0103] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0104] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the bottom liquid is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the temperature of the bottom of the column is 102℃ and the toluene yield is 91%.

[0105] The material level added to the bottom of the tower is 70%; the toluene recovery rate from the top of the tower when switching the forced circulation pipeline is 65%; the half-apex angle α of the conical head shell of the bottom of the tower is 40°; the ratio of the height of the bottom liquid circulation inlet pipe (H2) to the height of the conical head (H1) is 0.15.

[0106] Example 7

[0107] (1) A material is added to the batch distillation column (1) through the feed line (a), the composition of which is: toluene 90 wt%, 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) 9.8 wt%, 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB) 0.2 wt%, and water 0.01 wt%;

[0108] (2) Control the batch distillation column (1) to achieve a vacuum of 35 kPa;

[0109] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, the reflux ratio is controlled to be 1 to 2.5, and toluene is collected through toluene collection pipeline (c);

[0110] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0111] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the bottom liquid is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the temperature of the bottom of the column is 108℃ and the toluene yield is 93%.

[0112] The material level added to the bottom of the tower is 70%; the toluene recovery rate from the top of the tower when switching the forced circulation pipeline is 65%; the half-apex angle α of the conical head shell of the bottom of the tower is 40°; the ratio of the height of the bottom liquid circulation inlet pipe (H2) to the height of the conical head (H1) is 0.15.

[0113] Example 8

[0114] (1) A material is added to the batch distillation column (1) through the feed line (a), the composition of which is: toluene 90 wt%, 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB) 9.8 wt%, 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB) 0.2 wt%, and water 0.01 wt%;

[0115] (2) Control the batch distillation column (1) to reach a vacuum of 0 kPa;

[0116] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, the reflux ratio is controlled to be 1 to 2.5, and toluene is collected through toluene collection pipeline (c);

[0117] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0118] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the bottom liquid is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the temperature of the bottom of the column is 130°C and the toluene yield is 97%.

[0119] The material level added to the bottom of the tower is 70%; the toluene recovery rate from the top of the tower when switching the forced circulation pipeline is 65%; the half-apex angle α of the conical head shell of the bottom of the tower is 40°; the ratio of the height of the bottom liquid circulation inlet pipe (H2) to the height of the conical head (H1) is 0.15.

[0120] Example 9

[0121] (1) A material is added to the batch distillation column (1) through the feed line (a), the composition of which is: 75 wt% toluene, 24.2 wt% 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), 0.8 wt% 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB), and 0.01 wt% water;

[0122] (2) Control the batch distillation column (1) to reach a vacuum of 55 kPa;

[0123] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, the reflux ratio is controlled to be 1 to 2.5, and toluene is collected through toluene collection pipeline (c);

[0124] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0125] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the liquid in the bottom of the column is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the temperature of the bottom of the column is 110℃ and the toluene yield is 90%.

[0126] The material level added to the bottom of the tower is 60%; the toluene recovery rate from the top of the tower when switching the forced circulation pipeline is 60%; the half-apex angle α of the conical head shell of the bottom of the tower is 30°; the ratio of the height of the bottom liquid circulation inlet pipe (H2) to the height of the conical head (H1) is 0.1.

[0127] Example 10

[0128] (1) A material is added to the batch distillation column (1) through the feed line (a), the composition of which is: 75 wt% toluene, 24.2 wt% 1,3,5-trichloro-2,4,6-trinitrobenzene (TCTNB), 0.8 wt% 1,3,5-trichloro-2,6-dinitrobenzene (TCDNB), and 0.01 wt% water;

[0129] (2) Control the batch distillation column (1) to reach a vacuum of 55 kPa;

[0130] (3) Open valve (3), heating steam pipeline (d) and condensate pipeline (e), heat the bottom liquid of the column through reboiler (6), the bottom liquid of the column is heated through non-forced circulation pipeline (f), the top steam of the column is condensed through condenser (2), so that the distillation column generates total reflux, the reflux ratio is controlled to be 1 to 2.5, and toluene is collected through toluene collection pipeline (c);

[0131] (4) Before the liquid in the bottom of the tower reaches saturation, close valve (3), open the pre-cut valve (4) and the post-cut valve (7), start the circulation pump (8), switch to the forced circulation pipeline (g), and make the reboiler of the tower a forced circulation type;

[0132] (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the bottom liquid is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the temperature of the bottom of the column is 110℃ and the toluene yield is 91%.

[0133] The material level added to the bottom of the tower is 75%; the toluene recovery rate from the top of the tower when switching the forced circulation pipeline is 60%; the half-apex angle α of the conical head shell of the bottom of the tower is 45°; the ratio of the height of the bottom liquid circulation inlet pipe (H2) to the height of the conical head (H1) is 0.2.

[0134] As can be seen from Examples 1-10, when the material level in the reboiler is 60-75%, the semi-apex angle α of the conical head in the reboiler is 30-45°, the ratio of the reboiler liquid circulation inlet pipe height (H2) to the conical head height (H1) is 0.1-0.2, and the toluene content is high or low, when the vacuum degree is 80 kPa, the reboiler temperature is low, but the toluene recovery is less than 80%; when the vacuum degree is 35-55 kPa, the reboiler temperature is not higher than 115°C, and the toluene recovery is not less than 90%; when the vacuum degree is 0 kPa, the reboiler temperature is higher than 130°C, and the toluene recovery is close to 90%. To effectively prevent pipeline blockage, reduce reboiler scaling, lower operating temperature, improve toluene recovery rate, and ensure the safety of separating energetic materials, the optimal vacuum degree should be controlled at 35-55 kPa, the reboiler temperature should not exceed 115°C, and the toluene recovery should not be less than 90%.

[0135] This invention provides a method for separating energetic materials and solvent toluene. To reduce the separation temperature of energetic materials and solvent toluene, the vacuum degree of the batch distillation column is controlled to lower the batch distillation operating temperature, thereby increasing the toluene recovery rate and improving the safety of the separation and purification operation. To prevent the precipitation of small solid particles that may clog the pipeline after a certain amount of toluene is collected from the top of the column due to the increased concentration of the material in the bottom of the column, a non-forced circulation pipeline (f) is used before the liquid in the bottom of the column reaches saturation, thereby reducing fluid resistance and pump energy consumption. As toluene is gradually collected from the top of the batch distillation column, the toluene recovery rate gradually increases, and the TCTNB concentration in the bottom of the column increases, which may cause small solid particles to precipitate in the bottom of the column. A forced circulation pipeline (g) is used to force the bottom of the column to circulate the material. The equipment has a simple structure and can prevent solid particles from clogging the pipeline and reduce reboiler scaling.

Claims

1. A method for recovering TCTNB-containing compounds via forced circulation in the reboiler of a vacuum batch distillation column, characterized in that: Includes the following steps: (1) Add the material to be purified into the batch distillation column through the feed pipeline; (2) Control the vacuum level of the batch distillation column to achieve the effect of pressure reduction; (3) The column bottom is heated by reboiler, and the column bottom liquid is heated by non-forced circulation pipeline to generate total reflux in the distillation column. The reflux ratio at the top of the distillation column is set so that toluene is collected through the collection pipeline. (4) Before the liquid in the bottom of the column reaches saturation, switch the forced circulation pipeline and start the circulation pump to make the reboiler in the bottom of the column a forced circulation type; (5) When tiny solid particles are suspended and precipitated in the bottom of the column, the bottom liquid is about to reach saturation. Stop the toluene collection from the top of the column. At this time, the amount of toluene collected from the top of the column is the toluene yield.

2. The method for forced recycling of TCTNB-containing materials through a vacuum batch distillation column reboiler as described in claim 1, characterized in that, Step (2) Control the vacuum degree of the batch distillation column to 35-55 kPa.

3. The method for forced recycling of TCTNB-containing compounds in the reboiler of a vacuum batch distillation column as described in claim 1, characterized in that, The preferred yield of toluene extracted from the top of the tower during step (4) of switching the forced circulation pipeline is 50-65%.

4. The method for forced circulation recovery of TCTNB-containing compounds in the reboiler of a vacuum batch distillation column as described in claim 1, characterized in that, In step (5), the toluene yield from the top of the tower reaches 90% to 93%.

5. A device for forced circulation recovery of TCTNB-containing compounds from the reboiler of a vacuum batch distillation column; characterized in that the device... include: The distillation column includes a batch distillation unit, a condenser, a Y-type filter, a reboiler, and a circulating pump. The distillation column reboiler is equipped with a forced circulation pipeline containing the circulating pump and a non-forced circulation pipeline without the circulating pump. The forced circulation pipeline is equipped with a Y-type filter.

6. The apparatus for forced circulation recovery of TCTNB-containing materials from the reboiler of a vacuum batch distillation column as described in claim 4; characterized in that, The distillation column reboiler is designed with a conical head, and the semi-apex angle α of the conical shell is between 30 and 45°.

7. The apparatus for forced circulation recovery of TCTNB-containing materials from the reboiler of a vacuum batch distillation column as described in claim 4; characterized in that, The reboiler structure of the distillation column includes a reboiler liquid circulation outlet, a reboiler liquid circulation inlet, and a waste pipeline. The reboiler liquid circulation outlet is located on the side of the conical head, and the ratio of the height of the reboiler liquid circulation inlet pipe to the height of the conical head is 0.1 to 0.

2.

8. The apparatus for forced circulation recovery of TCTNB-containing materials from the reboiler of a vacuum batch distillation column as described in claim 4; characterized in that, Forced circulation pipelines are installed on the two pipelines containing circulation pumps in the reboiler of the distillation column.

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