Production device of potassium nitrate

Abstract

The utility model discloses a potassium nitrate production device. A reaction tank is connected with a cooling crystallization tank, the cooling crystallization tank is connected with a first-stage filter press, the first-stage filter press is connected with a rinsing tank, the rinsing tank is connected with a second-stage filter press through a pipeline, and the second-stage filter press is connected with a potassium nitrate storage tank through a potassium nitrate fluidized bed; the first-stage filter press is connected with a first-stage mother liquor tank, the first-stage mother liquor tank is connected with a first-effect heater, a second-effect heater, a second-effect heater and a third-effect heater in series, the third-effect heater is connected with an ammonium chloride filter press, and the ammonium chloride filter press is connected with an ammonium chloride storage tank through an ammonium chloride fluidized bed. The continuous and stable potassium nitrate production is realized, the pH in the reaction can be accurately controlled, and the long-term stable operation of the device and the reaction is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of agricultural potassium nitrate fertilizer production, and in particular relates to a potassium nitrate production device. Background Art

[0002] Potassium nitrate is mainly used in glass processing, ceramic fireworks, military industry, food and medicine in industry; in agriculture, potassium nitrate is a highly efficient chlorine-free potassium-nitrogen compound fertilizer, widely used in cash crops such as tobacco, tea, fruits, flowers and vegetables. Potassium nitrate is an important soil conditioner that can provide nitrogen, potassium and other elements required by plants and promote plant growth. With the advancement of agricultural technology and the improvement of farmers' awareness, the demand for potassium nitrate continues to increase. At the same time, the challenges facing global agriculture, such as severe soil erosion and nutrient loss, have also increased the demand for potassium nitrate.

[0003] At present, the production of potassium nitrate mainly includes synthesis, solvent extraction, double decomposition, ion exchange and nitrate soil preparation. Among them, double decomposition is the main production method of industrial potassium nitrate. In China, the main methods used are sodium nitrate-potassium chloride method and ammonium nitrate-potassium chloride method. The former has a higher raw material price and the economic value of the by-product sodium chloride is lower. The ammonium nitrate-potassium chloride double decomposition process is widely used, and the four-step circulation method is the main one: water and potassium chloride are added to the circulating mother liquor, and potassium nitrate crystals are precipitated when the temperature is lowered. Solid ammonium nitrate is added to the mother liquor, and then after evaporation concentration and cooling crystallization, ammonium chloride crystals are precipitated, and the separated mother liquor is returned as the circulating mother liquor.

[0004] Chinese patent CN1827526A discloses a method for preparing potassium nitrate by double decomposition. After the raw materials potassium chloride, ammonium nitrate and process water are prepared in a certain proportion, they are sent to a vacuum cooling crystallizer, and potassium nitrate crystals are precipitated and grown; the crystal liquid is thickened by a thickener and then separated into potassium nitrate product by a centrifuge; the separated mother liquor is sent to a natural circulation evaporator for evaporation and concentration after heat exchange with the reaction liquid; the concentrated solution is crystallized by cold precipitation, thickened by a thickener, and then separated into ammonium chloride byproduct by a centrifuge. However, the temperature in the production process is relatively high, the corrosion resistance of the equipment material is relatively strict, and the intermittent operation of heat exchange with external circulating water for cold precipitation crystallization makes the efficiency low.

[0005] Chinese patent CN101628723A discloses a method for generating potassium nitrate and ammonium chloride by double decomposition reaction. At a temperature of 110°C, ammonium nitrate and potassium chloride are dissolved in water in a ratio of ammonium ion to chloride ion of 1:2, potassium chloride and water are continuously added, and potassium chloride and water are stirred while heating to reach a supersaturated state of potassium nitrate, and heating is stopped to cool the solution to 36-40°C in a vacuum cooling crystallizer to precipitate potassium nitrate crystals, and put into a centrifuge lined with filter cloth to obtain crude potassium nitrate, and the separated mother liquor I is another co-saturation point of potassium nitrate and ammonium chloride. The crude potassium nitrate is washed with cold water and dried to obtain finished potassium nitrate, and ammonium nitrate is added to the mother liquor I and the washing liquid, and the solution concentration is adjusted to a saturated state of ammonium chloride, and negative pressure evaporation is performed in a vacuum concentrator, and the precipitated ammonium chloride is centrifugally filtered to obtain a solid ammonium chloride product. However, it has the problem of high viscosity of the secondary effect material and reduced heat exchange coefficient, which leads to a decrease in production capacity.

[0006] Chinese patent CN104310443B discloses a continuous potassium nitrate production system and production method combined with liquid ammonium nitrate production, which is composed of a potassium nitrate production system and a liquid ammonium nitrate production system, improves the production efficiency of the potassium nitrate production process, controls the crystallization process more accurately, and makes the quality and output of potassium nitrate crystals more stable. However, the liquid ammonia is evaporated into gaseous ammonia and then reacted with dilute nitric acid to generate ammonium nitrate, and then the ammonium nitrate is reacted with a mixed solution containing ammonium chloride and potassium chloride to prepare potassium nitrate. The risk factor of the raw materials in the production process is high, and the requirements for the air tightness and operation of the device are relatively high. Summary of the invention

[0007] In view of the above technical problems, the utility model provides a potassium nitrate production device, which realizes continuous and stable production of potassium nitrate, can accurately control the pH in the reaction, and improve the long-term stable operation of the device and the reaction.

[0008] In order to achieve the above purpose, the utility model provides a potassium nitrate production device, a reaction tank is connected with a cooling crystallization tank, the cooling crystallization tank is connected with a primary filter press, the primary filter press is connected with a water washing tank, the water washing tank is connected with a secondary filter press pipeline, and the secondary filter press is connected with a potassium nitrate storage tank via a potassium nitrate fluidized bed.

[0009] Preferably, the first-stage filter press is connected to the first-stage mother liquor tank, the first-stage mother liquor tank is connected to the first-effect heater, the first-effect heater, the second-effect heater and the third-effect heater are connected in series, the third-effect heater is connected to the ammonium chloride filter press, and the ammonium chloride filter press is connected to the ammonium chloride storage tank via the ammonium chloride fluidized bed.

[0010] Further preferably, a fourth agitator and a fourth pH meter are provided in the primary mother liquid tank.

[0011] Further preferably, the ammonium chloride filter press is connected to the reaction tank.

[0012] Preferably, the reaction tank is connected to the potassium chloride storage tank and the ammonium nitrate storage tank via pipelines respectively.

[0013] Further preferably, the reaction tank is provided with a first agitator and a first pH meter; the cooling crystallization tank is provided with a second agitator and a second pH meter; and the washing tank is provided with a third agitator and a third pH meter.

[0014] Preferably, the secondary filter press is connected to the reaction tank.

[0015] Preferably, the water outlet of the cooling crystallization tank is connected to a cold water tank via a pipeline, and the cold water tank is connected to the water inlet of the cooling crystallization tank

[0016] The beneficial effects of the utility model are:

[0017] 1. A reaction tank and a cooling crystallization tank capable of continuously performing double decomposition reaction are used to connect potassium chloride and ammonium nitrate to react and generate ammonium chloride and potassium nitrate, and then filter press, separate and dry to obtain potassium nitrate crystals that meet the quality standards and have a water content of about 0.5%. At the same time, the mother liquor produced by the filter press is concentrated by a series heater, and then filter press and dry to obtain the ammonium chloride product; at the same time, the potassium nitrate and ammonium chloride are filtered to return the separated solution to the reaction tank for cyclic reaction, thereby improving resource utilization.

[0018] 2. The reaction tank, cooling crystallization tank, primary mother liquor tank and water washing tank are equipped with stirring devices and pH meters to promote reaction and crystallization, monitor the pH of the solution in real time, and accurately control the production of potassium nitrate and ammonium chloride, so that the device can operate stably for a long period of time.

[0019] 3. The utility model realizes the continuous production of potassium nitrate that meets the standards, and the by-product ammonium chloride filtrate obtained can be circulated and concentrated for the production of ammonium chloride products, with good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The utility model is a schematic diagram of the device structure, in which 1 is a potassium chloride storage tank, 2 is an ammonium nitrate storage tank, 3 is a reaction tank, 4 is a cooling crystallization tank, 5 is a cold water tank, 6 is a primary filter press, 7 is a primary mother liquor tank, 8 is a single-effect heater, 9 is a second-effect heater, 10 is a triple-effect heater, 11 is an ammonium chloride filter press, 12 is an ammonium chloride fluidized bed, 13 is an ammonium chloride storage tank, 14 is a washing tank, 15 is a secondary filter press, 16 is a potassium nitrate fluidized bed, 17 is a potassium nitrate storage tank, 18 is a first agitator, 19 is a first pH meter, 20 is a second agitator, 21 is a second pH meter, 22 is a third agitator, 23 is a third pH meter, 24 is a fourth agitator, and 25 is a fourth pH meter. DETAILED DESCRIPTION

[0021] The technical solution of the utility model is further explained below in conjunction with the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the utility model and should not be understood as limiting the utility model. The protection scope of the utility model shall be based on the content recorded in the claims. Any modification or replacement made by a person skilled in the art to the technical solution of the utility model without creative work shall fall within the protection scope of the utility model.

[0022] Example 1

[0023] A production device for potassium nitrate, wherein a reaction tank 3 is connected to a cooling crystallization tank 4, the cooling crystallization tank 4 is connected to a primary filter press 6, the primary filter press 6 is connected to a water washing tank 14, the water washing tank 14 is connected to a secondary filter press 15 by pipeline, and the secondary filter press 15 is connected to a potassium nitrate storage tank 17 via a potassium nitrate fluidized bed 16.

[0024] Preferably, the primary filter press 6 is connected to the primary mother liquor tank 7, the primary mother liquor tank 7 is connected to the first-effect heater 8, the first-effect heater 8, the second-effect heater 9 and the third-effect heater 10 are connected in series, the third-effect heater 10 is connected to the ammonium chloride filter press 11, and the ammonium chloride filter press 11 is connected to the ammonium chloride storage tank 13 via the ammonium chloride fluidized bed 12.

[0025] Further preferably, the ammonium chloride filter press 11 is connected to the reaction tank 3 .

[0026] Preferably, the reaction tank 3 is connected to the potassium chloride storage tank 1 and the ammonium nitrate storage tank 2 via pipelines respectively.

[0027] Further preferably, the reaction tank 3 is provided with a first agitator 18 and a first pH meter 19; the cooling crystallization tank 4 is provided with a second agitator 20 and a second pH meter 21; and the washing tank 14 is provided with a third agitator 22 and a third pH meter 23.

[0028] Preferably, the secondary filter press 15 is connected to the reaction tank 3 .

[0029] Preferably, the water outlet of the cooling crystallization tank 4 is connected to the cold water tank 5 via a pipeline, and the cold water tank 5 is connected to the water inlet of the cooling crystallization tank 4.

[0030] Example 2

[0031] Potassium chloride and ammonium nitrate are transported to the reaction tank 3 from the potassium chloride storage tank 1 and the ammonium nitrate storage tank 2 through pipelines, respectively, and reacted while stirring under the action of the first agitator 18 to generate a mixed solution containing ammonium chloride and potassium nitrate, and the reaction pH is monitored in real time by the first pH meter 19; the mixed solution is pumped into the cooling crystallization tank 4, and cooled and crystallized while stirring under the action of the second agitator 20, wherein cooling water is transported from the cold water tank 5 to the cooling crystallization tank 4 to cool the mixed solution and precipitate potassium nitrate crystals;

[0032] The mixed solution containing potassium nitrate crystals is pumped into the primary filter press 6 for filtration to separate the potassium nitrate crystals and the mother liquor, wherein the potassium nitrate crystals are sent to the washing tank 14, stirred and washed under the action of the third agitator 22, and the pH of the solution in the washing tank is monitored by the third pH meter, and then the washed mixed solution is pumped into the secondary filter press 15 for secondary filtration to obtain potassium nitrate precipitate with a water content of 20%, and finally dried in the potassium nitrate fluidized bed 16 to obtain potassium nitrate with a water content of about 0.5%, which is stored in the potassium nitrate storage tank 17.

[0033] The mother liquor separated by the primary filter press 6 is transported to the primary mother liquor tank 7, stirred and temporarily stored under the action of the fourth agitator 24, and the pH value of the mother liquor is monitored by the fourth pH meter; the mother liquor is then pumped into the first-effect heater 8, the second-effect heater 9 and the third-effect heater 10 in sequence to heat and concentrate the mother liquor to obtain ammonium chloride slurry with a solid content of about 40%; the ammonium chloride slurry is pumped into the ammonium chloride filter press 11 for filtration to obtain ammonium chloride solid with a water content of about 20%, and then the ammonium chloride solid is transported to the ammonium chloride fluidized bed 12 for heating and drying to obtain ammonium chloride crystals with a water content of about 0.5%, which are stored in the ammonium chloride storage tank 13.

[0034] The liquid obtained by filtration and separation by the ammonium chloride filter press 11 and the secondary filter press 15 is transported back to the reaction tank 3 for cyclic reaction.

[0035] The water outlet of the cooling crystallization tank 4 is connected to the cold water tank 5 via a pipeline, and the cold water tank 5 is connected to the water inlet of the cooling crystallization tank 4. The circulating cold water is used to circulate and cool the mixed solution in the cooling crystallization tank 4 to promote the crystallization of potassium nitrate.

Claims

1. A production device for potassium nitrate, characterized in that: The reaction tank (3) is connected to the cooling crystallization tank (4), the cooling crystallization tank (4) is connected to the primary filter press (6), the primary filter press (6) is connected to the water washing tank (14), the water washing tank (14) is connected to the secondary filter press (15) via a pipeline, and the secondary filter press (15) is connected to the potassium nitrate storage tank (17) via a potassium nitrate fluidized bed (16).

2. A production device for potassium nitrate according to claim 1, characterized in that: The primary filter press (6) is connected to the primary mother liquor tank (7), the primary mother liquor tank (7) is connected to the primary effect heater (8), the primary effect heater (8), the secondary effect heater (9) and the tertiary effect heater (10) are connected in series, the tertiary effect heater (10) is connected to the ammonium chloride filter press (11), and the ammonium chloride filter press (11) is connected to the ammonium chloride storage tank (13) via the ammonium chloride sulfiding bed (12).

3. A production device for potassium nitrate according to claim 2, characterized in that: The first-level mother liquid tank (7) is provided with a fourth agitator (24) and a fourth pH meter (25).

4. A production device for potassium nitrate according to claim 2, characterized in that: The ammonium chloride filter press (11) is connected to the reaction tank (3).

5. A production device for potassium nitrate according to claim 1, characterized in that: The reaction tank (3) is connected to the potassium chloride storage tank (1) and the ammonium nitrate storage tank (2) via pipelines respectively.

6. A production device for potassium nitrate according to claim 5, characterized in that: The reaction tank (3) is provided with a first stirrer (18) and a first pH meter (19); the cooling crystallization tank (4) is provided with a second stirrer (20) and a second pH meter (21); and the washing tank (14) is provided with a third stirrer (22) and a third pH meter (23).

7. A production device for potassium nitrate according to claim 1, characterized in that: The secondary filter press (15) is connected to the reaction tank (3).

8. A production device for potassium nitrate according to claim 1, characterized in that: The water outlet of the cooling crystallization tank (4) is connected to the cold water tank (5) via a pipeline, and the cold water tank (5) is connected to the water inlet of the cooling crystallization tank (4).

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