Sulfuric acid process titanium dioxide metatitanic acid adiabatic evaporation cooling device

Abstract

A sulfuric acid process titanium dioxide metatitanic acid adiabatic evaporation cooling device comprises a hydrolysis tank, a flash evaporator, a gas-liquid separation device, a condenser, a liquid seal storage tank and a vacuum system. The hydrolysis tank is communicated with the flash evaporator, the upper part of the flash evaporator is communicated with the gas-liquid separation device, the lower part of the flash evaporator is communicated with the liquid seal storage tank, the gas-liquid separation device is communicated with the condenser, and the condenser is communicated with the vacuum system. According to the device, hydrated titanium dioxide after hydrolysis in a titanium dioxide production process is cooled in a flash evaporation mode, the defects that a traditional cooling device is prone to scaling and blocking can be overcome by combining the structure of the flash evaporator, and heat of materials can be effectively utilized.

Description

Technical Field

[0001] The utility model relates to the field of sulfuric acid process titanium dioxide production process device, in particular to a sulfuric acid process titanium dioxide hydrolyzed material cooling device. Background Art

[0002] The sulfuric acid method is the main process for producing pigment-grade TiO2 in China. The production process mainly includes acidolysis, crystallization, filtration, concentration, hydrolysis, washing, salt treatment, calcination, initial crushing, coating, drying, and post-crushing. The hydrolysis process is to hydrolyze the titanium sulfate solution under a certain process. The final reaction product is mainly 25%-30% sulfuric acid at a temperature of 110°C and hydrated titanium dioxide with a content of about 180g / L, also known as metatitanic acid (H2TiO3), and there are also nearly saturated silicon calcium ions. Because the subsequent process generally uses a diaphragm filter press or a high-position mole unit for solid-liquid separation and filtration and washing of solid hydrated titanium dioxide, the temperature tolerance of this type of filtration and washing equipment is generally 70°C, and the equipment is prone to deformation and aging above this temperature. Therefore, the material obtained after hydrolysis needs to be cooled to below 70°C before entering the subsequent process. Most of the waste sulfuric acid separated by the subsequent washing process is generally concentrated to a concentration of 50% by evaporation and concentration of the waste acid and then reused for acidolysis. The technology for which a patent or utility model is applied in this article is mainly aimed at the process of cooling the material after hydrolysis.

[0003] In the process of cooling the high-temperature hydrated titanium dioxide suspension after hydrolysis, the domestic process generally uses circulating cooling water as the refrigerant, and uses a block-hole graphite heat exchanger to perform inter-wall heat transfer cooling on the high-temperature material after hydrolysis, and then puts it into a storage tank for use in the subsequent process. The cooling water is cooled by the cooling tower and then recycled.

[0004] The suspension after hydrolysis contains a large amount of silicon and calcium ions, and has a high solid content. Due to these material characteristics, the block-hole graphite heat exchanger used in the existing process has the disadvantages of easy scaling and clogging, time-consuming and labor-intensive maintenance, poor cooling effect and damage to subsequent equipment. At the same time, the heat of this part of the material from 110℃ to 60℃ is not used. Utility Model Content

[0005] The utility model aims to provide a sulfuric acid process titanium dioxide metatitanic acid adiabatic evaporation cooling device to solve the problems raised in the above background technology.

[0006] To achieve the above purpose, the technical solution is as follows:

[0007] A sulfuric acid process titanium dioxide metatitanic acid adiabatic evaporation cooling device, comprising: a hydrolysis tank, a flash evaporator, a gas-liquid separation device, a condenser, a liquid-sealed storage tank and a vacuum system; the hydrolysis tank is connected to the flash evaporator, the upper part of the flash evaporator is connected to the gas-liquid separation device, the lower part of the flash evaporator is connected to the liquid-sealed storage tank, the gas-liquid separation device is connected to the condenser, and the condenser is connected to the vacuum system.

[0008] Furthermore, the flash evaporator is provided with three flash tubes, the main body of the flash evaporator is an upper elliptical head with a cyclone and a steam outlet, the middle part of the flash evaporator is a cylinder, three flash tube tangent inlets with different heights are opened on the cylinder, the flash tubes are connected to the tangent inlets through 90° elbows, and the bottom of the flash evaporator is a conical bottom with a discharge flange.

[0009] Furthermore, the flash evaporator is connected to the liquid-sealed storage tank via a discharge pipe with a liquid seal at the bottom of the flash evaporator.

[0010] Furthermore, the vacuum system adopts a water ring vacuum pump.

[0011] Furthermore, the gas-liquid separation device adopts a cyclone separator.

[0012] The beneficial effects of the utility model are as follows:

[0013] 1. This device uses a flash evaporator to reduce the pressure of the hydrolyzed suspension and adiabatically evaporate it to replace the inter-wall heat exchange to achieve the process purpose of cooling. The hydrolyzed material is pumped into the flash evaporator. The pressure in the flash evaporator is generally set to 0.01-0.02Mpa depending on the cooling demand. The pressure is obtained by a water ring vacuum pump or other vacuum device. The material enters the flash evaporator and becomes a superheated solution due to the pressure reduction. It boils and evaporates instantly. The evaporated water vapor is separated by the gas-liquid separation device and then enters the condenser or the water jet pump for condensation and discharge. The flashed material is input into the liquid seal storage tank through the discharge pipe with a certain height at the bottom of the flash evaporator, and then pumped into the next process for use. In this way, the high temperature of the suspension can be used by the flash evaporator to make it evaporate further, and a higher concentration of material can be obtained while cooling.

[0014] 2. At the same time, due to the structure of the flash evaporator, the material is immediately superheated and evaporated into a large amount of steam after entering the flash evaporation tube, forming a high-speed steam flow in the tube, carrying the material through the 90° elbow and then tangentially entering the flash evaporator tank, forming a rotating airflow in the tank, flushing to prevent wall caking, and increasing the evaporation area; the direction of the rotating airflow is the same as the top swirl blade in the flash evaporator, and the centrifugal force is used to the maximum extent to separate the gas and liquid to prevent acid droplets from entering the subsequent condensation vacuum system. In this way, the disadvantages of easy scaling and clogging brought by the traditional cooling process can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1It is a diagram of a hydrolysis cooling system in the prior art;

[0016] Figure 2 This is a structural diagram of the cooling device of the utility model;

[0017] Figure 3 This is a structural diagram of a flash evaporator of the utility model;

[0018] Figure 4 It is a top view of the flash evaporator of the utility model;

[0019] Figure 5 This is a flow chart of the hydrolysis cooling system of the utility model.

[0020] The meaning of each number in the figure is:

[0021] 1. Hydrolysis tank; 2. Flash evaporator; 3. Gas-liquid separation device; 4. Condenser; 5. Liquid-sealed storage tank; 6. Vacuum system; 7. Cooling tower; 21. Flash tube; 22. Upper elliptical head; 23. Cyclone; 24. Steam outlet; 25. Flash tube tangential inlet; 26. 90° elbow; 27. Discharge flange. DETAILED DESCRIPTION

[0022] The technical solution of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present utility model, rather than all of the embodiments.

[0023] The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0024] Based on the embodiments of the present utility model, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present utility model.

[0025] Example:

[0026] A sulfuric acid process titanium dioxide metatitanic acid adiabatic evaporation cooling device, comprising: a hydrolysis tank 1, a flash evaporator 2, a gas-liquid separation device 3, a condenser 4, a liquid-sealed storage tank 5 and a vacuum system 6; the hydrolysis tank 1 is connected to the flash evaporator 2, the upper part of the flash evaporator 2 is connected to the gas-liquid separation device 3, the lower part of the flash evaporator 2 is connected to the liquid-sealed storage tank 5, the gas-liquid separation device 3 is connected to the condenser 4, and the condenser 4 is connected to the vacuum system 6.

[0027] Furthermore, the flash evaporator 2 is provided with three flash tubes 21, the main body of the flash evaporator 2 is an upper elliptical head 22 with a cyclone 23 and a steam outlet 24, the middle part of the flash evaporator 2 is a cylinder, and three flash tube tangent inlets 25 with different heights are opened on the cylinder, the flash tube 21 is connected to the tangent inlet 25 through a 90° elbow 26, and the bottom of the flash evaporator is a conical bottom with a discharge flange 27.

[0028] Furthermore, the flash evaporator 2 is connected to the liquid-sealed storage tank 5 via a discharge pipe with a liquid seal at the bottom of the flash evaporator.

[0029] Furthermore, the vacuum system 6 adopts a water ring vacuum pump.

[0030] Furthermore, the gas-liquid separation device 3 adopts a cyclone separator.

[0031] Furthermore, the condenser 4 is connected to a cooling tower 7 .

[0032] This device uses a flash evaporator to reduce the pressure of the hydrolyzed suspension liquid and adiabatically evaporate it to replace the inter-wall heat exchange to achieve the process purpose of cooling. The hydrolyzed material is pumped into the flash evaporator. The pressure in the flash evaporator is generally set to 0.01-0.02Mpa depending on the cooling demand. The pressure is obtained by a water ring vacuum pump or other vacuum devices. The material enters the flash evaporator and becomes a superheated solution due to the pressure reduction. It boils and evaporates instantly. The evaporated water vapor is separated by the gas-liquid separation device and then enters the condenser or the water jet pump for condensation and discharge. The flashed material is input into the liquid seal storage tank through the discharge pipe at the bottom of the flash evaporator, and then pumped into the next process for use.

[0033] The flash evaporator is made of anti-corrosion material and is equipped with three flash risers. The main body is an upper elliptical head with a cyclone and steam outlet, the middle is a cylinder, with three flash tube tangent inlets of different heights on the top, and a conical bottom with a discharge flange at the bottom.

[0034] The special design point lies in the three flash tubes and the feed port. The diameter of the flash tube is determined according to the volume of evaporated water vapor. After the material enters the flash tube, a large amount of steam is immediately flashed out, forming a high-speed steam flow in the tube, entraining the material through the 90° elbow and then tangentially entering the flash tank, forming a rotating airflow in the tank, flushing and preventing wall caking, while increasing the evaporation area. The direction of the rotating airflow is the same as that of the top swirl blade in the flash evaporator, making the most of the centrifugal force for gas-liquid separation to prevent acid droplets from entering the subsequent condensation vacuum system.

[0035] The above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it; although the utility model is described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model.

[0036] Finally, it should be noted that the utility model is not limited to the above optional implementations, and anyone can derive other various forms of products under the inspiration of the utility model. The above specific implementations should not be understood as limiting the scope of protection of the utility model. The scope of protection of the utility model shall be based on the definition in the claims, and the description can be used to interpret the claims.

Claims

1. A sulfuric acid process titanium dioxide metatitanic acid adiabatic evaporation cooling device, characterized in that: include: A hydrolysis tank (1), a flash evaporator (2), a gas-liquid separation device (3), a condenser (4), a liquid-sealed storage tank (5) and a vacuum system (6); the hydrolysis tank (1) is connected to the flash evaporator (2), the upper part of the flash evaporator (2) is connected to the gas-liquid separation device (3), the lower part of the flash evaporator (2) is connected to the liquid-sealed storage tank (5), the gas-liquid separation device (3) is connected to the condenser (4), and the condenser (4) is connected to the vacuum system (6). The flash evaporator (2) is provided with three flash tubes (21). The main body of the flash evaporator (2) is an upper elliptical head (22) with a cyclone (23) and a steam outlet (24). The middle part of the flash evaporator (2) is a cylinder. Three flash tube tangent inlets (25) of different heights are opened on the cylinder. The flash tubes (21) are connected to the tangent inlets (25) via a 90° elbow (26). The bottom of the flash evaporator is a conical bottom with a discharge flange (27).

2. The sulfuric acid process titanium dioxide metatitanic acid adiabatic evaporation cooling device according to claim 1, characterized in that: The flash evaporator (2) is connected to the liquid-sealed storage tank (5) via a discharge pipe with a liquid seal at the bottom of the flash evaporator.

3. The sulfuric acid process titanium dioxide metatitanic acid adiabatic evaporation cooling device according to claim 1, characterized in that: The vacuum system (6) adopts a water ring vacuum pump.

4. The sulfuric acid process titanium dioxide metatitanic acid adiabatic evaporation cooling device according to claim 1, characterized in that: The gas-liquid separation device (3) adopts a cyclone separator.

5. The sulfuric acid process titanium dioxide metatitanic acid adiabatic evaporation cooling device according to claim 1, characterized in that: The condenser (4) is connected to a cooling tower (7).

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