Ammonia distillation tower for continuous ammonia distillation process of o-nitrate

Abstract

The ammonia still comprises a tower body, 26 layers of tower trays are arranged in the tower body from bottom to top, the structures of the adjacent tower trays are the same, the adjacent tower trays are oppositely installed, baffle plates are installed at the front ends of the tower trays, and concave step areas are arranged on installation portions at the rear ends of the tower trays. The lower end of the baffle plate at the front end of the upper layer of tower tray extends into the central range of the concave step area at the rear end of the adjacent lower layer of tower tray; a feeding hole is formed between the last four to seven trays at the upper part of the tower body; an ammonia gas outlet is formed in the tower top; a direct steam inlet is formed below the lowest tray at the lower part of the tower body; a liquid phase outlet is formed in the center of the tower bottom; a tower top thermometer port, a tower top pressure gauge port, a tower bottom thermometer port and a tower bottom pressure gauge port are respectively arranged below the tower tray at the bottom of the tower body and above the tower tray at the top of the tower body, and liquid level meter ports are respectively arranged at the lower part of the tower body close to the lowest tray of the tower and the tower bottom. The utility model solves the problems in the prior art.

Description

Technical Field

[0001] The utility model relates to an ammonia recovery process in the production of o-nitrotoluene, and specifically relates to an ammonia distillation tower for the continuous ammonia distillation process of o-nitrotoluene. Background Art

[0002] In the prior art of the o-nitrotoluene production process, the discontinuous ammonia distillation process is generally adopted, and the equipment for discontinuous ammonia distillation is an ammonia distillation kettle. Its deficiencies and defects are as follows: 1. The tar content in the wastewater after ammonia distillation is high, resulting in a very dark color of the centrifuged p-nitrotoluene; the conventional solution is to use a high-power jet pump to increase the vacuum degree and reduce the ammonia distillation temperature. 2. The inlet pipeline of the ammonia distillation tower is prone to pipe blockage during operation; the conventional solution is to stop the feed pump for a few minutes every shift to blow the pipe. However, the conventional method has low efficiency and poor effect.

[0003] For other similar technologies, such as in the coal coking production process, the structure of the ammonia distillation tower used is not suitable for application in the o-nitrotoluene production process. For example, the technical literature we retrieved: "An Efficient Ammonia Distillation Tower Capable of Online Cleaning", CN201821068083.8, this technology is not applicable to this industry. Another example: Another retrieved literature "Ammonia Distillation Tower and Ammonia Distillation System", CN201720981686.6, the ammonia distillation tower equipment involved is applied in the production process of high-purity magnesium hydroxide coke, and its structure is also not suitable for application in the o-nitrotoluene production process. Therefore, new processes and equipment need to be designed to solve the problems existing in the prior art of the o-nitrotoluene production process. Summary of the Utility Model

[0004] The technical objective of the utility model is to provide an ammonia distillation tower for the continuous ammonia distillation process of o-nitrotoluene, which uses the ammonia distillation tower to replace the ammonia distillation kettle, changes the discontinuous ammonia distillation into continuous ammonia distillation, realizes automation, improves labor efficiency, and saves labor; solves the problems of product performance quality or production efficiency caused by the existing discontinuous process and equipment.

[0005] In order to achieve the above technical purpose, the technical scheme adopted by the utility model is: an ammonia distillation tower for continuous ammonia distillation process of ortho-nitrogen, which includes a tower body, 26 layers of tower plates are arranged from bottom to top in the tower body, adjacent tower plates are installed relatively with the same structure, a baffle is installed at the front end of the tower plate, a concave step area is arranged at the mounting part of the rear end of the tower plate close to the tower wall, and the lower end of the baffle at the front end of the upper tower plate extends to the central range of the concave step area at the rear end of the adjacent tower plate of the next layer; a feed port is arranged at the upper part of the tower body between the 4th to 7th tower plates from the bottom, an ammonia outlet is arranged at the top of the tower, a direct steam inlet is arranged at the lower part of the tower body below the lowest tower plate, a liquid phase outlet is arranged at the center of the tower bottom, a tower base is arranged at the lower part of the tower body below the tower bottom, a tower top thermometer port, a tower top pressure gauge port, a tower bottom thermometer port, a tower bottom pressure gauge port are respectively arranged at the bottom of the tower body below the tower plate and the top of the tower body above the tower plate, and a liquid level gauge port is respectively arranged at the lower part of the tower body near the lowest tower plate and near the bottom of the tower. The liquid phase outlet at the bottom of the tower is connected to the wastewater discharge pump, and then connected to the wastewater external pipe through a flowmeter and a water outlet regulating valve. The liquid level gauge on the tower body is interlocked with the water outlet regulating valve to maintain the liquid level in the tower. The feed port is connected to the wastewater feed pump through a feed wastewater thermometer, a feed wastewater pressure gauge, a wastewater regulating valve and a wastewater flowmeter. The wastewater flowmeter is interlocked with the wastewater regulating valve to control the water intake. The direct steam inlet is directly connected to the steam source through a steam regulating valve, and the thermometer is interlocked with the steam regulating valve to ensure the ammonia vapor temperature.

[0006] Furthermore, the utility model is provided with a shaft ear which is convenient for hoisting at the upper part of the tower body and above the uppermost tower plate.

[0007] Furthermore, the utility model is provided with manhole inlets at the tower bottom and the tower top respectively for the convenience of maintenance.

[0008] Furthermore, the utility model provides an inspection port at the lowermost tower plate of the tower body.

[0009] Furthermore, the utility model is also provided with a spare opening at the bottom of the tower body.

[0010] Furthermore, the utility model is provided with a tower base manhole on the tower base.

[0011] The process of continuous ammonia distillation using the utility model is:

[0012] 1. Start-up of ammonia distillation tower (continuous ammonia distillation)

[0013] 1.1. When the liquid level in the wastewater buffer tank reaches above 2m, the ammonia distillation tower is started.

[0014] 1.2. Open the steam valve (opening degree 30%) to preheat the ammonia distillation tower. When the tower bottom temperature reaches above 100℃ and the tower top temperature reaches above 80℃, start the liquid inlet pump and open the liquid inlet valve to inlet liquid. Gradually increase the liquid inlet amount to ensure that the tower bottom temperature is not lower than 100℃.

[0015] 1.3. When the liquid level in the tower exceeds 0.4 meters, open the drainage pump and drainage valve, and adjust the drainage valve to interlock automatic (the drainage valve opening is interlocked with the tower bottom liquid level, and the interlock value is 0.4 meters)

[0016] 2. Run

[0017] 2.1. During operation, the liquid inlet flow rate is set to 6-7m³. The interlocking water inlet regulating valve is adjusted automatically, and the goal is to control the ammonia distillation tower to run continuously for 24 hours. 2.2. During operation, the tower bottom temperature is maintained at 100-110℃, and the tower top temperature is not lower than 80 degrees.

[0018] The beneficial effects of the utility model are as follows: the utility model adopts the top liquid inlet and the bottom direct steam inlet, and the steam and the tower plate are fully in contact through 26 layers of tower plate baffles, which ensures that the ammonia evaporation effect and steam consumption remain unchanged, and can well prevent the material in the wastewater from clogging the equipment, without the need for cleaning and other problems that require stopping the machine.

[0019] The utility model adopts an ammonia evaporation tower to replace an ammonia evaporation kettle, and changes intermittent ammonia evaporation into continuous ammonia evaporation, realizing automation, improving labor efficiency, and saving labor. The ammonia evaporation effect is greatly improved. The ammonia content in the wastewater of the original ammonia evaporation kettle is 1%, and the ammonia content in the wastewater is reduced to 0.04% after the ammonia evaporation tower is used. The steam consumption is reduced. The steam consumption per ton of water of the original ammonia evaporation kettle is 237Kg, and the steam consumption per ton of water of the ammonia evaporation tower is 140Kg. About 195Kg of para- and ortho-nitrogen are recovered daily. The color of ammonium chloride was brown before the technical transformation, and the color of ammonium chloride was white after the technical transformation, which greatly improved the quality of ammonium chloride products. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The utility model is a schematic structural diagram of an embodiment of an ammonia distillation tower for a continuous ammonia distillation process of o-nitrate.

[0021] Figure 2 The utility model is a process flow diagram of an embodiment of an ammonia distillation tower for a continuous ammonia distillation process of o-nitrate.

[0022] In the figure, a is the feed port, b is the ammonia outlet, c is the direct steam inlet, d is the tower bottom liquid phase outlet, e is the reserved pipeline outlet, f is the spare port, g is the upper liquid level gauge port, h is the lower liquid level gauge port, k1 is the tower top manhole, k2 is the tower bottom manhole, t1 is the tower top thermometer port, t2 is the tower bottom thermometer port, p1 is the tower top pressure gauge port, p2 is the tower bottom pressure gauge port, n is the tower base manhole, and m is the inspection port;

[0023] 1 foundation formwork, 2 tower base, 3 tower bottom head, 4 tower plate, 5 tower body, 6 shaft ear, 7 tower top cone. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] As attached Figure 1-2 As shown, an embodiment of an ammonia distillation tower for continuous ammonia distillation process of ortho-nitrogen nitrate is provided, which includes a tower body 5, in which 26 layers of tower trays 4 are arranged from bottom to top, and are numbered from 1# to 26# from bottom to top; adjacent tower trays have the same structure and are relatively installed, a baffle 41 is installed at the front end of the tower tray 4, and a concave step area 42 is provided at the mounting portion of the rear end of the tower tray 4 close to the tower wall, and the lower end of the baffle 41 at the front end of the tower tray 4 of the upper layer extends to the central range of the concave step area 42 at the rear end of the adjacent tower tray of the next layer. A feed inlet a is provided at the upper part of the tower body 5 between the 4# to 7# tower plates from the bottom, the tower top is in a frustum shape, an ammonia outlet b is provided at the top of the tower top cone portion 7, a direct steam inlet c is provided at the lower part of the tower body 5 below the 1# tower plate, a liquid phase outlet d is provided in the center of the tower bottom, a tower base 2 is provided at the lower part of the tower body 5 below the tower bottom head 3, a tower top thermometer port t1, a tower top pressure gauge port p1, a tower bottom thermometer port t2, and a tower bottom pressure gauge port p2 are provided at the bottom of the tower body 5 below the 1# tower plate and at the top of the tower body above the 26# tower plate, respectively, and liquid level gauge ports, namely an upper liquid level gauge port g and a lower liquid level gauge port h, are provided at the lower part of the tower body near the 26# tower plate and near the tower bottom head, respectively.

[0026] The liquid phase outlet d at the bottom of the tower is connected to the wastewater discharge pump, and then connected to the wastewater outer pipe through the flowmeter and the outlet water regulating valve. The liquid level meter installed on the tower body is interlocked with the outlet water regulating valve to maintain the liquid level in the tower. The feed port a is connected to the wastewater feed pump through the wastewater regulating valve and the wastewater flowmeter and is equipped with a feed wastewater thermometer and a feed wastewater pressure gauge. The wastewater flowmeter is interlocked with the wastewater regulating valve to control the water intake. The direct steam inlet c is directly connected to the steam source through the steam regulating valve, and the thermometer installed on the tower body is interlocked with the steam regulating valve to ensure the ammonia vapor temperature. (reference Figure 2 )

[0027] like Figure 1 As shown, a shaft ear 6 is provided on the upper part of the tower body 5 above the top 26# tower plate for easy lifting. Manhole entrances are provided at the bottom and top of the tower, namely, the top manhole k1 and the bottom manhole k2, which are used for easy maintenance. An inspection port m is provided at the 26# tower plate at the bottom of the tower body (with a flange cover). A spare port f is also provided at the bottom of the tower body. A tower base manhole n is also provided on the tower base 2. A reserved pipeline outlet e is also provided on the tower base 2. The foundation template 1 of the fixed structure of the tower base 2 is shown in the attached figure. Figure 1shown.

[0028] The process of continuous ammonia distillation using the utility model ammonia distillation tower is:

[0029] 1. Start-up of ammonia distillation tower (continuous ammonia distillation)

[0030] 1.1. When the liquid level in the wastewater buffer tank reaches above 2m, the ammonia distillation tower is started.

[0031] 1.2. Open the steam valve (opening degree 30%) to preheat the ammonia distillation tower. When the tower bottom temperature reaches above 100℃ and the tower top temperature reaches above 80℃, start the liquid inlet pump and open the liquid inlet valve to inlet liquid. Gradually increase the liquid inlet amount to ensure that the tower bottom temperature is not lower than 100℃.

[0032] 1.3. When the tower bottom liquid level exceeds 0.4 meters, open the drain pump and drain valve, and adjust the drain valve to interlock automatic (the drain valve opening is interlocked with the tower bottom liquid level, and the interlock value is 0.4 meters)

[0033] 2. Run

[0034] 2.1. During operation, the liquid inlet flow rate is set to 6-7m³. The interlocking water inlet regulating valve is automatically adjusted to control the ammonia distillation tower to operate continuously for 24 hours.

[0035] 2.2. During operation, the tower bottom temperature should be maintained at 100-110°C and the tower top temperature should not be lower than 80°C.

Claims

1. An ammonia still for continuous ammonia still process of o-nitrate, comprising a tower body, characterized in that: There are 26 layers of tower plates from bottom to top in the tower body, and adjacent tower plates with the same structure are installed opposite to each other. A baffle is installed at the front end of the tower plate, and a concave step area is provided at the installation part of the rear end of the tower plate close to the tower wall. The lower end of the baffle at the front end of the upper tower plate extends to the central range of the concave step area at the rear end of the adjacent tower plate of the next layer; a feed port is provided between the last 4 to 7 tower plates at the upper part of the tower body, an ammonia outlet is provided at the top of the tower, a direct steam inlet is provided at the lower part of the tower body below the lowest tower plate, a liquid phase outlet is provided in the center of the tower bottom, a tower base is provided at the lower part of the tower body below the tower bottom, a tower top thermometer port and a tower top pressure gauge port, and a tower bottom thermometer port and a tower bottom pressure gauge port are provided at the bottom of the tower body below the tower plate and at the top of the tower body above the tower plate, respectively, and a liquid level gauge port is provided at the lower part of the tower body near the lowest tower plate and near the bottom of the tower.

2. The ammonia still for continuous ammonia still process of ortho-nitre according to claim 1, characterized in that: A shaft ear for facilitating lifting is arranged on the upper part of the tower body and above the uppermost tower plate.

3. The ammonia still for continuous ammonia still process of ortho-nitre according to claim 1, characterized in that: Manhole entrances are provided at the bottom and top of the tower for easy maintenance.

4. The ammonia still for continuous ammonia still for ortho-nitre still according to claim 1, characterized in that: An inspection port is provided at the lowest tower plate of the tower body.

5. The ammonia still for continuous ammonia still for ortho-nitre still according to claim 1, characterized in that: There is also a spare opening at the bottom of the tower.

6. The ammonia still for continuous ammonia still process of ortho-nitre according to claim 1, characterized in that: A tower base manhole is provided on the tower base.

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