Heating concentration device

Abstract

The invention discloses a heating concentration device, and belongs to the field of chemical equipment. The heating concentration device is cylindrical closed equipment composed of an outer layer structure, a middle layer structure and an inner layer structure, the outer layer of the device is a stainless steel shell, the middle layer is an insulating acid-resistant heat preservation material, the inner layer is a graphite kettle, the graphite kettle is provided with a sealing cover, and the graphite kettle and the sealing cover form a cylindrical closed space. The device is reasonable in layout, simple in structure, small in fluid resistance, uniform in fluid distribution, easy to install, overhaul, maintain and clean, wide in application range and suitable for heating, concentration and impurity removal production systems of various specifications and models.

Description

Technical Field

[0001] The invention relates to industrial production equipment, in particular to a cylindrical closed equipment composed of an outer layer, a middle layer and an inner layer, which has the functions of heating, concentrating and removing impurities, can be used for heating, concentrating and removing impurities of a solution, and can be widely used in the process of industrial production. Background Art

[0002] Phosphoric acid produced by decomposing phosphate rock with sulfuric acid (hereinafter referred to as wet-process phosphoric acid) accounts for the vast majority of phosphoric acid production. Wet-process phosphoric acid contains a large amount of impurities. During transportation and storage, these impurities will precipitate and precipitate, causing many troubles and causing P 2 O 5 If wet phosphoric acid is further heated and concentrated to make superphosphoric acid, the polyphosphoric acid in it can chelate these impurities so that they no longer precipitate, and the product is more suitable for transportation and storage. 2 O 5 Mass concentration ≥ 68% is called superphosphoric acid. Superphosphoric acid is less corrosive than orthophosphoric acid, and low carbon steel also has good corrosion resistance to superphosphoric acid at room temperature. Superphosphoric acid is used to produce liquid fertilizers. Since the polyphosphoric acid in it can chelate impurities in the acid and make them exist in the solution, and the solubility of polyphosphate is relatively high, superphosphoric acid can be used to produce liquid fertilizers with higher concentrations. Adding a small amount of superphosphoric acid when producing granular compound fertilizers can reduce the return ratio, reduce the amount of dust in the system, and make the particles harder and more wear-resistant. High concentrations of superphosphoric acid can be used as a catalyst and dehydrating agent in the organic chemical industry.

[0003] In addition to fertilizers, wet-process phosphoric acid is difficult to be widely used in other industrial fields. Thermal phosphoric acid is usually used in these occasions. Compared with wet-process phosphoric acid, thermal phosphoric acid is a high-energy consumption and high-pollution product. If wet-process phosphoric acid is used to produce high-quality phosphates to meet the requirements of food-grade, pharmaceutical-grade and electronic-grade products, the wet-process phosphoric acid must be purified to produce high-purity phosphoric acid. By heating and concentrating wet-process phosphoric acid to above 400°C, the metal ions in phosphoric acid can form pyrophosphate precipitation. Removing this part of the precipitation can not only purify the phosphoric acid, but also significantly reduce the viscosity of the phosphoric acid, making it suitable for phosphoric acid transportation and subsequent processing.

[0004] Therefore, it is urgent to provide a device for heating concentrated wet-process phosphoric acid, which can produce concentrated phosphoric acid, superphosphoric acid, and purify phosphoric acid. Summary of the invention

[0005] The purpose of the present invention is to provide a heating and concentrating device, which is a cylindrical closed device composed of an outer, middle and inner three-layer structure, and has the functions of heating, concentrating and removing impurities. It can be used for heating, concentrating and removing impurities of solutions, and can be widely used in industrial production processes. The patent has a reasonable layout, simple structure, small fluid resistance, uniform fluid distribution, easy installation and maintenance, easy maintenance and cleaning, and a wide range of applications. It is suitable for heating, concentrating and removing impurities production systems of various specifications and models.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A heating and concentrating device is a cylindrical closed device composed of an outer, middle and inner three-layer structure. The outer layer of the device is a stainless steel shell, the middle layer is an insulating acid-resistant heat-preserving material, and the inner layer is a graphite kettle with a sealing cover. The graphite kettle and the sealing cover form a cylindrical closed space.

[0008] The graphite kettle of the heating and concentrating device is provided with a feed channel, the sealing cover is provided with a feed pipe, the feed channel is connected with the feed pipe; the graphite kettle is provided with a discharge channel and a discharge pipe.

[0009] The outlet B of the feed channel is located at the bottom of the graphite kettle; the inlet F of the discharge channel is higher than the outlet B of the feed channel, and the discharge pipe forms an angle α with the vertical direction, α≤90°.

[0010] The sealing surface of the graphite kettle is provided with a sealing convex surface, the sealing cover is provided with a sealing concave surface, and the graphite kettle and the sealing cover are sealed and connected via the concave and convex surfaces.

[0011] The sealing cover is also provided with an air outlet pipe, a graphite electrode, an electrical insulation ring, and a thermocouple; the gas generated in the graphite kettle is discharged through the air outlet pipe; the graphite electrode is separated from the sealing cover by the electrical insulation ring and the lowest point J is located below the liquid surface; the graphite electrode can move up and down; the heat in the graphite kettle is provided by the alternating current between the graphite electrode and the graphite kettle wall; the current intensity is adjusted by the rise and fall of the graphite electrode under a fixed voltage. The lowest point K of the thermocouple is located below the liquid surface and is used to measure the temperature of the liquid in the graphite kettle.

[0012] The inner diameter of the graphite kettle is D, the gas phase height is Hg, the liquid phase height is Hl, the wall thickness is δ, and the heating concentration temperature is ≤650°C.

[0013] In some specific technical solutions, a heating and concentrating device has the functions of heating, concentrating and removing impurities, which can be used for heating, concentrating and removing impurities of solutions, and can be widely used in industrial production processes. The solution from the boundary area enters the bottom of the graphite kettle from the feed pipe and the feed channel, and the solution is heated and concentrated by the graphite electrode in the graphite kettle. The solution containing impurities generates precipitation under high temperature. The heated and concentrated solution is discharged from the discharge channel and the discharge pipe. The heating and concentrating device can process more than one solution. Take wet phosphoric acid as an example:

[0014] A heating and concentrating device is a cylindrical closed device composed of an outer, middle and inner three-layer structure. The outer layer of the device is a stainless steel shell, the middle layer is an insulating acid-resistant heat-preserving material, and the inner layer is a graphite kettle, the graphite kettle is provided with a sealing cover, and the graphite kettle and the sealing cover form a cylindrical closed space. The graphite kettle of the heating and concentrating device is provided with a wet phosphoric acid feed channel, the sealing cover is provided with a wet phosphoric acid feed pipe, and the wet phosphoric acid feed channel is connected to the wet phosphoric acid feed pipe; the graphite kettle is provided with a concentrated phosphoric acid discharge channel and a concentrated phosphoric acid discharge pipe.

[0015] The outlet B of the wet phosphoric acid feed channel is located at the bottom of the graphite kettle; the inlet F of the concentrated phosphoric acid discharge channel is higher than the outlet B of the wet phosphoric acid feed channel, and the concentrated phosphoric acid discharge pipe forms an angle α with the vertical direction, 0°≤α≤90°.

[0016] The sealing surface of the graphite kettle is provided with a sealing convex surface, the sealing cover is provided with a sealing concave surface, and the graphite kettle and the sealing cover are sealed and connected via the concave and convex surfaces.

[0017] The sealing cover is also provided with an air outlet pipe, a graphite electrode, an electrical insulation ring, and a thermocouple; the gas generated in the graphite kettle is discharged through the air outlet pipe; the graphite electrode is separated from the sealing cover by the electrical insulation ring and the lowest point J is located below the phosphoric acid liquid level in the graphite kettle; the graphite electrode can move up and down; the heat in the graphite kettle is provided by the alternating current between the graphite electrode and the graphite kettle wall; the current intensity is adjusted by the rise and fall of the graphite electrode under a fixed voltage. The lowest point K of the thermocouple is located below the phosphoric acid liquid level in the graphite kettle, and is used to measure the phosphoric acid temperature in the graphite kettle.

[0018] The inner diameter of the graphite kettle is D, the gas phase height is Hg, the liquid phase height is Hl, the wall thickness is δ, the temperature for producing concentrated phosphoric acid is 100°C≤200°C, the temperature for producing superphosphoric acid is 200°C≤400°C, and the temperature for producing purified phosphoric acid is 400°C≤500°C.

[0019] Beneficial effects of the present invention:

[0020] This patent provides a heating and concentrating device, which has the functions of heating, concentrating and removing impurities. It can be used for heating, concentrating and removing impurities of solutions. It can be widely used in industrial production processes. The heating material temperature can reach 650℃, and the application range is wide. When used to treat wet-process phosphoric acid, concentrated phosphoric acid is obtained below 200℃, superphosphoric acid is obtained below 400℃, and purified phosphoric acid is obtained below 500℃. The conductivity increases with the P in phosphoric acid. 2 O 5 The temperature decreases as the content increases, so the overheating phenomenon during heating is automatically adjusted.

[0021] The sealing surface of the graphite kettle has a sealing convex surface, and the sealing cover has a sealing concave surface. The graphite kettle and the sealing cover are sealed and connected through the convex and concave surfaces; the heat in the graphite kettle is provided by the alternating current between the graphite electrode and the wall of the graphite kettle, and the graphite electrode is separated from the sealing cover by an electrical insulating ring to avoid short circuit; the graphite electrode can move up and down, and the current intensity can be easily adjusted by raising and lowering the graphite electrode under a fixed voltage.

[0022] The outlet of the feed channel is located at the bottom of the graphite kettle. The solution with lower concentration boils at the bottom of the kettle to produce a stirring effect, which keeps the crystallized solid in the kettle suspended and overflows out of the kettle with the discharge.

[0023] By heating and concentrating wet phosphoric acid to above 170°C, organic matter is decomposed and carbonized; by heating and concentrating wet phosphoric acid to above 338°C, sulfuric acid evaporates; by heating and concentrating wet phosphoric acid to above 400°C, fluorine and sulfate in phosphoric acid are basically removed by exhaust gas, and metal ions form pyrophosphate precipitation; by removing the precipitate in phosphoric acid, the iron content in phosphoric acid is reduced to the original 55.76%, the aluminum content is reduced to the original 48.51%, and the magnesium content is reduced to the original 56.49%, the carbonized organic matter is completely removed, and the viscosity of phosphoric acid is significantly reduced, which is more suitable for phosphoric acid transportation and subsequent processing.

[0024] In this heating and concentrating device, phosphoric acid can be heated and concentrated to any desired concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a front cross-sectional view of the present invention.

[0026] Among them: 1 is a heating and concentrating device, 2 is a stainless steel shell, 3 is an insulating acid-resistant and heat-preserving material, 4 is a graphite kettle, 5 is a feed channel, 6 is a sealing convex surface, 7 is a sealing cover, 8 is a sealing concave surface, 9 is a feed pipe, 10 is an air outlet pipe, 11 is a graphite electrode, 12 is an electrical insulation ring, 13 is a thermocouple, 14 is a discharge channel, and 15 is a discharge pipe. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present patent to clearly and completely describe the technical solutions in the embodiments of the present patent. Obviously, the described embodiments are part of the embodiments of the present patent, not all of the embodiments. The components of the embodiments of the present patent described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present patent provided in the drawings is not intended to limit the scope of the patent claimed for protection, but only represents the selected embodiments of the present patent. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this patent. The embodiments of the present patent are described in detail below, and examples of the embodiments are shown in the drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below by reference to the drawings are exemplary and are intended to be used to explain the present patent, and cannot be understood as limitations on the present patent.

[0028] The present invention will be further described with reference to the accompanying drawings and specific embodiments. More than one solution can be treated. Taking the production of purified phosphoric acid by wet-process phosphoric acid as an example, the heating and concentration temperature is 430°C:

[0029] like Figure 1 A heating and concentrating device, characterized in that: the heating and concentrating device 1 is a cylindrical closed device composed of an outer, middle and inner three-layer structure, the outer layer of the device is a stainless steel shell 2, the middle layer is an insulating acid-resistant heat-preserving material 3, the inner layer is a graphite kettle 4, the graphite kettle 4 is provided with a sealing cover 7, and the graphite kettle 4 and the sealing cover 7 form a cylindrical closed space. The heating and concentrating device 1 has a wet phosphoric acid feed channel 5 on the graphite kettle 4, a wet phosphoric acid feed pipe 9 on the sealing cover 7, and the wet phosphoric acid feed channel 5 is connected to the feed pipe 9; the graphite kettle 4 has a concentrated phosphoric acid discharge channel 14 and a concentrated phosphoric acid discharge pipe 15.

[0030] The outlet B of the wet phosphoric acid feed channel 5 is located at the bottom of the graphite reactor 4; the inlet F of the concentrated phosphoric acid discharge channel 14 is higher than the outlet B of the wet phosphoric acid feed channel 5, and the concentrated phosphoric acid discharge pipe 15 forms an angle α with the vertical direction, α=60°. 2 O 5 The phosphoric acid (mass concentration 68.42%, room temperature) enters the bottom of the graphite kettle 4 from the wet-process phosphoric acid feed pipe 9 and the wet-process phosphoric acid feed channel 5 through the outlet B, where the wet-process phosphoric acid is heated and concentrated.

[0031] The sealing surface of the graphite kettle 4 is provided with a sealing convex surface 6, and the sealing cover 7 is provided with a sealing concave surface 8. The graphite kettle 4 and the sealing cover 7 are sealed and connected via the concave and convex surfaces.

[0032] The sealing cover 7 also has an outlet pipe 10, a graphite electrode 11, an electrical insulation ring 12, and a thermocouple 13; the gas (including P 2 O 5 The graphite electrode 11 is separated from the sealing cover 7 by an electrical insulating ring 12 and the lowest point J is below the liquid level. The graphite electrode 11 can move up and down. The heat in the graphite kettle 4 is provided by the alternating current between the graphite electrode 11 and the wall of the graphite kettle 4. The current intensity is adjusted by the rise and fall of the graphite electrode 11 at a fixed voltage. The voltage is fixed at 25V, the current is fixed at 120A, and the power consumption is 3kW. The lowest point K of the thermocouple 13 is below the liquid level and is used to measure the liquid temperature in the graphite kettle 4.

[0033] The inner diameter of the graphite kettle 4 is D=13 cm, the gas phase height is Hg=13 cm, the liquid phase height is Hl=10 cm, the wall thickness is δ=6 cm, and the heating concentration temperature is 430°C.

[0034] Concentrated phosphoric acid with pyrophosphate precipitate (containing P 2 O 5 The mass concentration is 80.12%, the temperature is 430°C) and the concentrated phosphoric acid is discharged from the concentrated phosphoric acid discharge channel 14 and the concentrated phosphoric acid discharge pipe 15 through the inlet F to separate the pyrophosphate precipitate in the phosphoric acid. After the pyrophosphate precipitate is separated, purified phosphoric acid without pyrophosphate precipitate is obtained. The operating results of the embodiment of the present invention are shown in Table 1

[0035] Table 1 185 kg / day purified phosphoric acid (at 100% P 2 O 5 Heating and Concentrating Device Performance Assessment Result Table

[0036]

[0037]

Claims

1. A heating and concentrating device, characterized in that: The heating and concentrating device (1) is a cylindrical closed device composed of three layers of outer, middle and inner structures, wherein the inner layer is a graphite kettle (4) and the graphite kettle (4) is provided with a sealing cover (7). The graphite kettle (4) and the sealing cover (7) form a cylindrical closed space; The graphite kettle (4) is provided with a feed channel (5), the sealing cover (7) is provided with a feed pipe (9), and the feed channel (5) is connected with the feed pipe (9); the graphite kettle (4) is provided with a discharge channel (14).

2. The heating and concentrating device according to claim 1, characterized in that: The outlet B of the feed channel (5) is located at the bottom of the graphite kettle (4); the discharge channel (14) is higher than the feed channel (5), and the discharge pipe (15) connected to the discharge channel forms an angle α with the vertical direction, 0°≤α≤90°.

3. The heating and concentrating device according to claim 1, characterized in that: The sealing surface of the graphite kettle (4) is provided with a sealing convex surface (6), and the sealing cover (7) is provided with a sealing concave surface (8). The graphite kettle (4) and the sealing cover (7) are sealed and connected via the concave and convex surfaces.

4. The heating and concentrating device according to claim 1, characterized in that: The sealing cover (7) is also provided with an air outlet pipe (10), a graphite electrode (11), an electrical insulation ring (12), and a thermocouple (13); the graphite electrode (11) can be moved up and down and is separated from the sealing cover (7) by the electrical insulation ring (12), and the lowest point is located below the liquid surface.

5. The heating and concentrating device according to claim 1, characterized in that: The inner diameter of the graphite kettle (4) is D, the gas phase height is Hg, the liquid phase height is Hl, the wall thickness is δ, and the room temperature is ≤ the heating concentration temperature ≤ 650°C.

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