WO2021248774A1 - Circulating type potassium nitrate crystallization device - Google Patents

Abstract

A circulating type potassium nitrate crystallization device, comprising a crystallizer tank (1), an overflow box (2), circulating pipes (3, 5, 7), a first circulating pump (4), a heat exchanger (6), a central pipe (8) and circulating flushing pipes (9). The central pipe (8) is provided in the middle of the crystallizer tank (1), and the overflow box (2) is arranged on the outer side wall of an upper end of the crystallizer tank (1). The circulating pipes (3, 5, 7) sequentially connect the overflow box (2), the first circulating pump (4), the heat exchanger (6) and the central pipe (8) in a sealed manner. There are several circulating flushing pipes (9), which are are evenly distributed around the outer side wall of the crystallizer tank (1) in a circumferential manner. Upper ends of the circulating flushing pipes (9) are inserted into a conical part (102) in the radial direction from the outer side wall of the middle of the conical part (102) and are connected in a sealed manner, and lower ends of the circulating flushing pipe (9) are tangentially inserted into a lower cylinder part (103) from the circumference of the outer side wall of a lower part of the lower cylinder part (103) and are connected in a sealed manner. A second circulating pump (901) is provided in the middle of the circulating flushing pipe (9). A mother liquor circulation continuous crystallization structure is used, which greatly improves the production efficiency. A plurality of circulating flushing pipes (9) which are circumferentially and uniformly distributed are used to enable crystal liquid at the bottom of the crystallizer to rotate, so that crystal grains may be effectively prevented from accumulating and blocking a discharging pipe, and smooth discharging is thus guaranteed.

Description

Circulating type potassium nitrate crystallization device Technical field

The invention relates to the technical field of potassium nitrate preparation, in particular to a circulating potassium nitrate crystallizer.

Background technique

Potassium nitrate is a colorless transparent rhombic or rhombic crystal white powder, easily soluble in water, insoluble in ethanol, and not easy to deliquesce in the air. The product is a strong oxidant and can burn and explode in contact with organic matter. Potassium nitrate is widely used in the agricultural market. Potassium nitrate is a chlorine-free potassium and nitrogen compound fertilizer. The total content of phytonutrient potassium and nitrogen can reach about 60%, and it has good physical and chemical properties. Potassium nitrate applied to tobacco has high fertilizer efficiency, is easy to absorb, promotes the early emergence of seedlings, increases tobacco yield, and improves tobacco quality. In the food industry, it is used as a hair coloring agent, color protection agent, antimicrobial agent, and preservative. It is reduced to potassium nitrite due to the action of bacteria in meat products to play a role in color protection and bacteriostasis, such as curing meat, Plays an antiseptic effect in luncheon meat. In the pharmaceutical industry, it is used to produce penicillin potassium salt and rifampin.

In the preparation process of potassium nitrate, a single kettle is used for sequential crystallization, which is a batch crystallization method. The heat transfer efficiency of the equipment is low, the amount of equipment is large, the investment is large, the production efficiency is low, and the particle size control of the product is difficult.

The Oslo evaporative crystallizer is a kind of mother liquor circulating continuous crystallizer. The operating material liquid is added to the circulating tube, mixed with the circulating mother liquid in the tube, and sent to the heating chamber by the pump. The heated solution evaporates in the evaporation chamber and reaches supersaturation, and enters the crystal fluidized bed below the evaporation chamber through the central tube. In the crystal fluidized bed, the supersaturated solute in the solution deposits on the surface of the suspended particles, causing the crystals to grow. The crystal fluidized bed performs hydraulic classification of the particles, with large particles on the bottom and small particles on the top, and the crystalline product with a relatively uniform particle size is discharged from the bottom of the fluidized bed. The fine particles in the fluidized bed flow into the circulation pipe with the mother liquor, and the tiny crystals are dissolved when reheated. If the heating chamber of the Oslo evaporative crystallizer is replaced by a cooling chamber and the evaporative chamber and the like are removed, the Oslo cooling crystallizer is constructed.

However, when the circulating cooling crystallizer of Oslo is used for potassium nitrate crystallization, the potassium nitrate solution is prone to precipitation inside the crystallizer, which makes the potassium nitrate crystallized unevenly, and the potassium nitrate cooling and crystallization speed is fast, and it is easy to block the discharge port after crystallization , Unable to discharge.

Summary of the invention

The purpose of the present invention is to provide a circulating potassium nitrate crystallization device to solve the problem that the existing Oslo cooling crystallizer proposed in the background art is used for potassium nitrate crystallization, which easily blocks the discharge port and cannot discharge the material.

In order to achieve the above objectives, the present invention provides the following technical solutions:

A circulating potassium nitrate crystallization device, which is characterized in that it comprises a crystallizer cylinder, an overflow box, a circulating pipe, a first circulating pump, a heat exchanger, a central pipe, and a circulating flushing pipe. The upper end of the crystallizer cylinder is open, For adding mother liquor, the crystallizer cylinder includes an upper cylindrical part, a conical part, a lower cylindrical part, and an arc-shaped cylinder bottom in sequence from top to bottom. The arc-shaped cylinder bottom is provided with a discharge tube, and the center tube It is set in the middle of the mold cylinder and inserted straight into the upper end of the bottom of the arc-shaped cylinder from the upper end of the mold cylinder. The lower end of the center tube is set as a conical tube whose diameter gradually expands downwards. The overflow box is set in the mold On the outer side wall of the upper end of the cylinder, the inner cavity is communicated with the inner cavity of the crystallizer cylinder, and the bottom is provided with an overflow port. The first circulation pump and the heat exchanger are both arranged on the outside of the crystallizer cylinder, and the circulation pipe is provided with multiple sections. , The overflow box, the first circulating pump, the heat exchanger, and the central pipe are connected in sequence. The circulating punching pipe is provided with a number of pieces, which are evenly distributed around the outer wall of the mold cylinder. The upper end of the circulating punching pipe The lower end of the circulation punch pipe is inserted into the lower cylindrical portion tangentially from the outer side wall of the lower cylindrical portion from the outer side wall of the middle portion of the cone portion and sealedly connected. Circulating pump is used to pump out the mother liquor from the cone part, and then rush into the lower cylinder part from the tangential direction of the lower cylinder part, so that the mother liquor at the lower end of the mold cylinder produces a rotating vortex, which drives the flow of the crystal grains at the bottom of the arc-shaped cylinder to prevent discharge The tube is clogged.

Further, there are 8 pieces of the circulating flushing pipe.

Further, the diameter of the circulating flushing pipe is set to 80-100 mm.

Further, the crystallizer cylinder, overflow box, central pipe, circulation pipe, and circulation flushing pipe are all made of 316 stainless steel.

Further, the heat exchanger adopts a tube-and-tube heat exchanger.

Further, the discharging pipe is provided with two pieces, and they are arranged obliquely at an angle of 30 degrees to the horizontal plane.

Further, between the inner side wall of the upper cylindrical portion and the outer side wall of the central tube is provided a plurality of first support rods uniformly distributed on the circumference, and the inner side wall of the bottom of the arc-shaped tube and the outer side wall of the conical tube at the lower end of the central tube are A plurality of second support rods uniformly distributed on the circumference are arranged in between.

Further, the motor of the first circulating pump adopts an adjustable motor, and the flow rate of the first circulating pump is adjusted by adjusting the rotation speed of the motor, thereby adjusting the crystal grain size in the circulating mother liquor and the number of crystal grains discharged from the discharge pipe.

Compared with the prior art, the present invention has the following beneficial effects: 1) adopting a mother liquor circulating continuous crystallization structure, so that potassium nitrate can be continuously and uninterruptedly crystallized and discharged, which greatly improves production efficiency; 2) adopting a plurality of uniformly distributed in a circle The circulating flushing tube makes the crystal liquid at the bottom of the crystallizer rotate, which can effectively prevent the accumulation of crystal grains from clogging the discharge pipe and ensure smooth discharge; 3) The bottom of the crystallizer cylinder is set to an arc-shaped cylinder bottom, which improves the liquid crystal The flow state in the crystallizer prevents the formation of dead zones to accumulate crystal grains.

Description of the drawings

Figure 1 is a schematic structural diagram of an embodiment of the present invention;

Figure 2 is a schematic top view of the structure of an embodiment of the present invention;

3 is a schematic diagram of the distribution structure of a multi-person circulation flushing pipe according to an embodiment of the present invention;

In the figure: 1. Mold cylinder, 101, upper cylindrical part, 102, conical part, 103, lower cylindrical part, 104, arc-shaped cylinder bottom, 105, first support rod, 106, second support rod, 107 , Discharge pipe, 2, overflow box, 201, overflow port, 3, circulation pipe 1, 4, first circulation pump, 5, circulation pipe 2, 6, heat exchanger, 7, circulation pipe 3, 8. Central tube, 9, circulation flushing tube, 901, second circulation pump.

detailed description

In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", " The orientation or positional relationship indicated by “outer”, “vertical”, “horizontal”, etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply the pointed device Or the element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

As shown in FIGS. 1 to 3, the embodiment of the present invention includes a crystallizer cylinder 1, an overflow box 2, a circulating pipe, a first circulating pump 4, a heat exchanger 6, a central pipe 8, and a circulating flushing pipe 9.

The upper end of the mold cylinder 1 is open for mother liquor. The mold cylinder 1 includes an upper cylindrical portion 101, a cone portion 102, a lower cylindrical portion 103, an arc-shaped barrel bottom 104, and an arc-shaped barrel from top to bottom. The bottom 104 is provided with a discharging tube 107, and the discharging tube 107 is provided with two pieces, which are inclined at an angle of 30 degrees with the horizontal plane.

The central tube 8 is set in the middle of the mold cylinder 1, and is inserted straight into the upper end of the arc-shaped cylinder bottom 104 from the upper end of the mold cylinder 1. Between the inner side wall of the part 101 and the outer side wall of the central tube 8 are provided a plurality of first support rods 105 uniformly distributed on the circumference. The pieces are second support rods 106 evenly distributed around the circumference.

The overflow box 2 is arranged on the outer side wall of the upper end of the crystallizer cylinder 1, the inner cavity is communicated with the inner cavity of the crystallizer cylinder 1, and an overflow port 201 is provided at the bottom.

The first circulating pump 4 and the heat exchanger 6 are both arranged on the outside of the crystallizer cylinder 1. The heat exchanger 6 is a tubular heat exchanger with a water inlet at the upper end and a water outlet at the lower end. In the heat exchanger The mother liquor flows from bottom to top in the tube, and the cold water flows from top to bottom on the outside of the tube, cold and hot convection, so that the mother liquid quickly cools down to the potassium nitrate saturated solution; the motor of the first circulating pump 4 adopts an adjustable motor, and the motor is adjusted. The rotation speed is used to adjust the flow rate of the first circulating pump 4, thereby adjusting the crystal grain size in the circulating mother liquor and the number of crystal grains discharged from the discharge pipe.

The circulation pipe is equipped with circulation pipe 1 3, circulation pipe 2 5, circulation pipe 3 7, overflow box 2, circulation pipe 1 3, first circulation pump 4, circulation pipe 2 5, heat exchanger 6, circulation pipe 3 7, and The central pipes are connected in a sealed manner.

There are 8 circulating punching pipes 9 arranged uniformly around the outer side wall of the mold cylinder 1. The upper end of the circulating punching pipe 9 is radially inserted into the cone portion 102 from the outer side wall of the middle of the cone portion 102 and connected in a sealed manner. The circulating punching pipe 9 The lower end is tangentially inserted into the lower cylindrical part 103 from the outer wall circumference of the lower part of the lower cylindrical part 103 and connected in a sealed manner. The cylindrical part 103 punches into the lower cylindrical part 103 in a tangential direction, so that the mother liquor at the lower end of the mold cylinder 1 generates a swirling vortex, which drives the crystal grains at the bottom 104 of the arc-shaped cylinder to flow, preventing the crystal grains from clogging the discharge tube 107 and failing to discharge the material. .

Preferably, the diameter of the circulating punch 9 is set to 80-100 mm.

Preferably, the mold cylinder 1, the overflow box 2, the central pipe 8, the circulating pipe one 3, the circulating pipe two 5, the circulating pipe three 7, and the circulating punching pipe 9 are all made of 316 stainless steel.

The working mode of the present invention: the mother liquor of 80 degrees is continuously added into the crystallizer cylinder 1, when the liquid level of the mother liquor exceeds the height of the overflow at the bottom of the overflow tank 2, the mother liquor will flow into the circulation pipe 3 from the overflow and start In the first circulation pump 4, the mother liquor enters the heat exchanger 6, and the mother liquor from the heat exchanger 6 is cooled to below 35 degrees, and then enters the central pipe 8, where potassium nitrate crystals are precipitated in the central pipe, and finally from the cone at the lower end of the central pipe 8. The nozzle of the shaped pipe flows into the bottom of the arc-shaped cylinder and discharges the material from the discharge port. A plurality of second circulating pumps 901 are activated to make the mother liquor in the cone part 102 enter the lower cylinder tangentially from the circumference of the lower cylindrical part 103 through the circulating punching pipe. The lower end of the crystallizer cylinder 1 causes the mother liquor to generate a swirling vortex, which drives the crystal grains at the bottom 104 of the arc-shaped cylinder to flow, thereby preventing the crystal grains from clogging the discharge pipe 107 and ensuring smooth discharge.

The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited to this. Anyone familiar with the technical field within the technical scope disclosed by the present invention, according to the technical solution of the present invention Equivalent replacements or changes to its inventive concept should all fall within the protection scope of the present invention.

Claims (8)

A circulating potassium nitrate crystallization device, which is characterized in that it comprises a crystallizer cylinder, an overflow box, a circulating pipe, a first circulating pump, a heat exchanger, a central pipe, and a circulating flushing pipe. The upper end of the crystallizer cylinder is open, For adding mother liquor, the crystallizer cylinder includes an upper cylindrical part, a conical part, a lower cylindrical part, and an arc-shaped cylinder bottom in sequence from top to bottom. The arc-shaped cylinder bottom is provided with a discharge tube, and the center tube It is set in the middle of the mold cylinder and inserted straight into the upper end of the bottom of the arc-shaped cylinder from the upper end of the mold cylinder. The lower end of the center tube is set as a conical tube whose diameter gradually expands downwards. The overflow box is set in the mold On the outer side wall of the upper end of the cylinder, the inner cavity is communicated with the inner cavity of the crystallizer cylinder, and the bottom is provided with an overflow port. The first circulation pump and the heat exchanger are both arranged on the outside of the crystallizer cylinder, and the circulation pipe is provided with multiple sections. , The overflow box, the first circulating pump, the heat exchanger, and the central pipe are connected in sequence. The circulating punching pipe is provided with a number of pieces, which are evenly distributed around the outer wall of the mold cylinder. The upper end of the circulating punching pipe The lower end of the circulating punch pipe is inserted into the lower cylindrical portion tangentially from the outer side wall of the lower cylindrical portion from the outer side wall of the central part of the cone and sealedly connected. Circulating pump is used to draw the mother liquor from the cone part, and then rush into the lower cylinder part from the tangential direction of the lower cylinder part, so that the mother liquor at the lower end of the crystallizer cylinder produces a swirling vortex, which drives the flow of the crystal grains at the bottom of the arc-shaped cylinder to prevent discharging The tube is clogged. The circulating potassium nitrate crystallization device according to claim 1, wherein the circulating flushing pipe is provided with 8 pieces. The circulating potassium nitrate crystallization device according to claim 1, wherein the diameter of the circulating flushing pipe is set to 80-100 mm. The circulating potassium nitrate crystallization device according to claim 1, characterized in that: the crystallizer cylinder, overflow box, central tube, circulation tube, and circulation flushing tube are all made of 316 stainless steel. The circulating potassium nitrate crystallization device according to claim 1, wherein the heat exchanger is a tubular heat exchanger. The circulating potassium nitrate crystallization device according to claim 1, characterized in that the discharge pipe is provided with two pieces, which are inclined at an angle of 30 degrees with respect to the horizontal plane. The circulating potassium nitrate crystallization device according to claim 1, wherein a plurality of first support rods uniformly distributed on the circumference are arranged between the inner side wall of the upper cylindrical part and the outer side wall of the central tube. A plurality of second support rods uniformly distributed on the circumference are arranged between the inner side wall of the bottom of the arc-shaped cylinder and the outer side wall of the conical tube at the lower end of the central tube. The circulating potassium nitrate crystallization device according to claim 1, wherein the motor of the first circulating pump adopts an adjustable motor, and the flow rate of the first circulating pump is adjusted by adjusting the motor speed, thereby adjusting the circulating mother liquor. The crystal grain size and the number of crystal grains discharged from the discharge tube.

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