Device for continuously filtering impurities in magnesium nitrate solution in production process of concentrated nitric acid

Abstract

The utility model relates to a magnesium nitrate solution impurity continuous filtering device in a concentrated nitric acid production process. The magnesium nitrate solution impurity continuous filtering device comprises a magnesium nitrate heater, a magnesium nitrate intermediate tank, a magnesium nitrate solution ground tank, a magnesium nitrate solution filter, a dilute magnesium nitrate tank and a magnesium nitrate evaporator which are sequentially communicated through pipelines, the inlet end of the magnesium nitrate heater is used for being connected with a concentration rectifying tower and heating and denitrifying a nitric acid-containing magnesium nitrate solution flowing out of the concentration rectifying tower; the magnesium nitrate solution ground tank is connected with a steam condensate pipe and is used for diluting a magnesium nitrate solution in the magnesium nitrate solution ground tank; the magnesium nitrate evaporator is used for being communicated with a concentrated magnesium nitrate tank. Compared with an existing magnesium nitrate solution impurity removal mode, the device does not need to be stopped, and the operation time of a production device is prolonged; meanwhile, the purposes of removing impurities in the magnesium nitrate solution, reducing equipment corrosion, prolonging the service life of equipment, reducing steam consumption and reducing the production cost are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of concentrated nitric acid production equipment, in particular to a device for continuously filtering impurities in a magnesium nitrate solution in a concentrated nitric acid production process. Background Art

[0002] Most of the concentrated nitric acid production enterprises in China adopt the magnesium nitrate production process, which is to first prepare dilute nitric acid, and then use magnesium nitrate as a dehydrating agent to concentrate and produce concentrated nitric acid, and the magnesium nitrate used is recycled as a dehydrating agent. Because the concentrated nitric acid production process uses ferrosilicon concentration towers and bleaching towers, and there are ceramic distributed fillers in the concentration towers and bleaching towers, and the process temperature during the production process is relatively high, during the production process, impurities such as rust and broken ceramic fillers corroded by the ferrosilicon reaction container will be mixed into the magnesium nitrate solution. With the increase of impurities mixed in, the effect of magnesium nitrate solution in removing nitric acid will become worse, corroding the equipment and reducing the life of the equipment. At the same time, the steam consumption of concentrated nitric acid production increases, and energy is wasted, resulting in an increase in production costs.

[0003] Most manufacturers stop the production to pump the magnesium nitrate solutions in the dilute magnesium nitrate tank and the concentrated magnesium nitrate tank into the magnesium nitrate solution sedimentation tank for impurity precipitation. The shutdown affects the production operation time of concentrated nitric acid. Utility Model Content

[0004] The utility model aims to provide a device for continuously filtering impurities in a magnesium nitrate solution during the production of concentrated nitric acid, so as to solve the technical problems raised in the background technology.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A device for continuously filtering impurities in a magnesium nitrate solution during concentrated nitric acid production comprises: a magnesium nitrate heater, a magnesium nitrate intermediate tank, a magnesium nitrate solution ground tank, a magnesium nitrate solution filter, a dilute magnesium nitrate tank and a magnesium nitrate evaporator which are sequentially connected through pipelines; the inlet end of the magnesium nitrate heater is used to be connected to a concentration and rectification tower to heat and denitrate the magnesium nitrate solution containing nitric acid flowing out of the concentration and rectification tower; the magnesium nitrate solution ground tank is connected to a steam condensate pipe to dilute the magnesium nitrate solution in the magnesium nitrate solution ground tank; and the magnesium nitrate evaporator is used to be connected to the concentrated magnesium nitrate tank.

[0007] As a further improvement of the utility model, the magnesium nitrate solution filter adopts a jacketed bag filter, and its filter bag is a polytetrafluoroethylene filter bag.

[0008] As a further improvement of the utility model, a pressure gauge is provided on the magnesium nitrate solution filter.

[0009] As a further improvement of the utility model, a heat-insulating layer is provided on the outer wall of the pipeline.

[0010] As a further improvement of the utility model, a power pump is provided on the pipeline between the magnesium nitrate solution trough and the magnesium nitrate solution filter.

[0011] As a further improvement of the utility model, a control valve is provided on the pipeline between the magnesium nitrate intermediate tank and the magnesium nitrate solution ground tank.

[0012] The beneficial effects of adopting the above technical solution are:

[0013] The utility model is installed between the magnesium nitrate heater and the magnesium nitrate evaporator in the magnesium nitrate solution evaporation process used in the existing concentrated nitric acid production, dilutes and filters the magnesium nitrate solution after dehydrating the dilute nitric acid in the concentration and rectification tower, and then puts it into the concentration and rectification tower for recycling. Compared with the existing magnesium nitrate solution impurity removal method, there is no need to stop the machine, which increases the operating time of the production device; at the same time, it also achieves the purpose of removing impurities from the magnesium nitrate solution, reducing equipment corrosion, extending the service life of the equipment, reducing steam consumption, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the process of the utility model;

[0015] Figure 2 This is a schematic diagram of the process flow of concentrated nitric acid preparation according to the utility model;

[0016] Explanation of marks in the figure: 1 magnesium nitrate heater, 2 magnesium nitrate intermediate tank, 3 magnesium nitrate solution ground tank, 4 magnesium nitrate solution filter, 5 dilute magnesium nitrate tank, 6 magnesium nitrate evaporator, 7 concentration distillation tower, 8 steam condensate pipe, 9 concentrated magnesium nitrate tank, 10 pressure gauge, 11 power pump, 12 bleaching tower, 13 cooling tower, 14 intermediate tank, 15 finished product tank, 16 dilute nitric acid absorption tower, 17 dilute nitric acid tank, 18 control valve, 19 concentrated magnesium nitrate buffer tank. DETAILED DESCRIPTION

[0017] In order to better understand the purpose, structure and function of the present invention, the present invention is described clearly and completely below in conjunction with the accompanying drawings.

[0018] like Figure 1The device for continuous filtering impurities of magnesium nitrate solution in a concentrated nitric acid production process shown comprises: a magnesium nitrate heater 1, a magnesium nitrate intermediate tank 2, a magnesium nitrate solution trough 3, a magnesium nitrate solution filter 4, a dilute magnesium nitrate tank 5 and a magnesium nitrate evaporator 6 which are sequentially connected through pipelines. The inlet end of the magnesium nitrate heater 1 is used to connect with a concentration distillation tower 7, and the magnesium nitrate solution containing nitric acid flowing out of the concentration distillation tower 7 is heated and denitrated to reduce equipment corrosion, so that the magnesium nitrate solution after dehydrating the dilute nitric acid in the concentration distillation tower 7 can flow smoothly into the magnesium nitrate intermediate tank 2. A control valve 18 is provided on the pipeline between the magnesium nitrate intermediate tank 2 and the magnesium nitrate solution trough 3 to control the flow of the magnesium nitrate solution flowing into the magnesium nitrate solution trough 3. Since the magnesium nitrate solution in the magnesium nitrate solution trough 3 is relatively thick, in order to facilitate subsequent filtration thereof, the magnesium nitrate solution trough 3 is connected to a steam condensate pipe 8 for introducing steam condensate into the magnesium nitrate solution trough 3 to dilute the magnesium nitrate solution in the magnesium nitrate solution trough 3. A control valve 18 is also provided on the steam condensate pipe 8. In addition, a liquid level sensor may be provided in the magnesium nitrate solution trough 3 to monitor the height of the liquid level in the magnesium nitrate solution trough 3. When the height of the magnesium nitrate solution in the magnesium nitrate solution trough 3 is too high or too low, the liquid level in the magnesium nitrate solution trough 3 is adjusted in time by adjusting the opening of the control valve 18 to ensure that the liquid level of the magnesium nitrate solution trough 3 is stable, thereby maintaining continuous filtration of the subsequent magnesium nitrate solution filter 4.

[0019] The diluted magnesium nitrate solution in the magnesium nitrate solution trough 3 flows through a pipeline to the magnesium nitrate solution filter 4 for impurity filtration. A power pump 11 is provided on the pipeline to provide power for the magnesium nitrate solution to flow into the magnesium nitrate solution filter 4. In this embodiment, the magnesium nitrate solution filter 4 adopts a jacketed bag filter, and its filter bag is a tetrafluoroethylene filter bag; and a pressure gauge 10 is provided on the magnesium nitrate solution filter 4. When the pressure displayed by the pressure gauge 10 increases to a certain value, the impurities are cleaned regularly and the filter bag is cleaned or replaced to ensure the filtering effect, realize the filtration of impurities in the magnesium nitrate solution during the concentrated nitric acid production process, and reduce the number of overall shutdowns of the device. The filtered magnesium nitrate solution flows into the dilute magnesium nitrate tank 5 and is collected, and the water therein is evaporated by the magnesium nitrate evaporator 6 to concentrate the dilute magnesium nitrate solution into a concentrated magnesium nitrate solution. The magnesium nitrate evaporator 6 is used to be connected to the concentrated magnesium nitrate tank 9. In addition, a concentrated magnesium nitrate buffer tank 19 is also connected between the concentrated magnesium nitrate tank 9 and the concentrating distillation tower 7. A power pump 11 is also provided on the pipeline between the concentrated magnesium nitrate buffer tank 19 and the concentrated magnesium nitrate tank 9, and then the concentrated magnesium nitrate solution is pumped into the concentrated magnesium nitrate buffer tank 19, and is retained by the height difference and injected into the concentrating distillation tower again for recycling.

[0020] To prevent heat dissipation, the outer wall of the pipe is provided with an insulation layer. The filtering device is installed between the magnesium nitrate heater 1 and the magnesium nitrate evaporator 6 in the magnesium nitrate solution evaporation process used in the existing concentrated nitric acid production, dilutes and filters the magnesium nitrate solution after dehydration of dilute nitric acid in the concentration distillation tower 7, and then puts it into the concentration distillation tower 7 for recycling. Compared with the existing magnesium nitrate solution impurity removal method, there is no need to stop the production unit, which increases the operating time of the production unit; at the same time, it also achieves the purpose of removing impurities from the magnesium nitrate solution, reducing equipment corrosion, extending equipment service life, reducing steam consumption, and reducing production costs.

[0021] Figure 2 In order to adopt the process flow chart of preparing concentrated nitric acid by the device, the discharge end of the concentration and rectification tower 7 is connected to the bleaching tower 12, the cooling tower 13, the intermediate tank 14 and the finished product tank 15 in sequence, and the prepared concentrated nitric acid is bleached, cooled and collected; the unqualified concentrated nitric acid in the cooling process is passed into the dilute nitric acid tank 17, and is put into the concentration and rectification tower 7 again with the concentrated magnesium nitrate solution for secondary concentration. The acidic steam evaporated from the magnesium nitrate evaporator 6 produces acidic water through rectification and washing, which is passed into the dilute nitric acid absorption tower 16 for recycling.

[0022] It is understood that the present invention is described by some embodiments, and those skilled in the art are aware that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A continuous filtering device for impurities in magnesium nitrate solution in a concentrated nitric acid production process, characterized in that: It includes: A magnesium nitrate heater (1), a magnesium nitrate intermediate tank (2), a magnesium nitrate solution trough (3), a magnesium nitrate solution filter (4), a dilute magnesium nitrate tank (5) and a magnesium nitrate evaporator (6) are sequentially connected via pipelines; the inlet end of the magnesium nitrate heater (1) is used to be connected to a concentration distillation tower (7) to heat and denitrate the magnesium nitrate solution containing nitric acid flowing out of the concentration distillation tower (7); the magnesium nitrate solution trough (3) is connected to a steam condensate pipe (8) to dilute the magnesium nitrate solution in the magnesium nitrate solution trough (3); and the magnesium nitrate evaporator (6) is used to be connected to a concentrated magnesium nitrate tank (9).

2. The device for continuous filtering impurities of magnesium nitrate solution in a concentrated nitric acid production process according to claim 1, characterized in that: The magnesium nitrate solution filter (4) is a jacketed bag filter, and its filter bag is a tetrafluoroethylene filter bag.

3. The device for continuous filtering impurities of magnesium nitrate solution in a concentrated nitric acid production process according to claim 1, characterized in that: The magnesium nitrate solution filter (4) is provided with a pressure gauge (10).

4. The device for continuous filtering impurities of magnesium nitrate solution in a concentrated nitric acid production process according to claim 1, characterized in that: The outer walls of the pipelines are all covered with a heat-insulating layer.

5. The device for continuous filtering impurities of magnesium nitrate solution in a concentrated nitric acid production process according to claim 1, characterized in that: A power pump (11) is provided on the pipeline between the magnesium nitrate solution trough (3) and the magnesium nitrate solution filter (4).

6. The device for continuous filtering impurities of magnesium nitrate solution in a concentrated nitric acid production process according to claim 1, characterized in that: A control valve (18) is provided on the pipeline between the magnesium nitrate intermediate tank (2) and the magnesium nitrate solution ground tank (3).

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