Tail gas cooling system in rare earth concentrate acid roasting process

Abstract

The utility model relates to a rare earth smelting technology, in particular to a device for cooling tail gas in a rare earth concentrate acid roasting process. A tail gas cooling system in an acid roasting rare earth concentrate process comprises a chilling cooler, a first-stage acid circulation tank connected with the chilling cooler, a first variable frequency pump with a water inlet formed in the upper half position of a first-stage acid circulation tank, and an infiltrated graphite plate type heat exchanger communicated with a water outlet pipe of the first variable frequency pump. The cold source circulating water tank is connected with the infiltrated graphite plate type heat exchanger through a second variable frequency pump, and the tail gas absorption system is connected with the cold source circulating water tank. According to the technical scheme, the connecting structure is simple, heat energy recycling can be effectively achieved, and fluorine-mixed acid resources can be effectively recycled.

Description

Technical Field

[0001] The utility model relates to rare earth smelting technology, in particular to a device for cooling tail gas in the process of acid roasting rare earth concentrate. Background Art

[0002] In the traditional acid roasting process of rare earth concentrate, the conventional method for treating high-temperature dust-containing, sulfuric acid and highly corrosive tail gas of sulfuric acid and fluorine compounds is through cold shock cooling, three-stage absorption and two-stage high-efficiency combined demisting device. These devices are usually combined with their own circulating acid and washing spray systems to ensure efficient absorption treatment. Although such a treatment method can achieve smokeless treatment of tail gas and meet national emission standards, it has several disadvantages: 1. Insufficient recovery and utilization of heat energy, resulting in energy waste. 2. The impact on the environment is still large, especially under high temperature and high acidity conditions, which can easily lead to the loss of rare earths. 3. The concentration of mixed acid is low and cannot be fully utilized, thereby increasing production costs. In order to solve these problems, it is necessary to develop a new technical solution that can improve the efficiency of tail gas cooling and also achieve the recovery and utilization of heat energy and resources. Utility Model Content

[0003] The utility model provides a tail gas cooling system in the process of acid roasting rare earth concentrate, so as to achieve an efficient, energy-saving and environmentally friendly tail gas cooling treatment device, which can effectively reduce the tail gas temperature, increase the concentration of mixed acid, reduce energy consumption, and reduce the wear and corrosion of equipment. In order to achieve the above technical purpose, the utility model adopts the following technical scheme: a tail gas cooling system in the process of acid roasting rare earth concentrate, including: a cold shock cooler, a primary acid circulation connected to the cold shock cooler, a first variable frequency pump with a water inlet arranged at the upper 1 / 2 of the primary acid circulation tank, an impregnated graphite plate heat exchanger connected to the water outlet pipe of the variable frequency pump, a cold source circulation water tank connected to the impregnated graphite plate heat exchanger through a second variable frequency pump, and a tail gas absorption system connected to the cold source circulation water tank.

[0004] Furthermore, the tail gas absorption system includes 1-3 levels of absorption towers.

[0005] Furthermore, a P membrane filter is provided between the primary acid circulation tank and the impregnated graphite plate heat exchanger.

[0006] Furthermore, it also includes a temperature sensor arranged at the outlet of the soaked graphite plate heat exchanger for monitoring the temperature of the mixed acid clear liquid after cooling, and arranged at the mixed acid outlet to ensure that the mixed acid temperature drops below 60°C.

[0007] Furthermore, a controller is included, which is connected to the temperature sensor, pressure sensor and frequency conversion pump through cables or wireless communication. The temperature sensor and pressure sensor monitor the corresponding process parameters (such as mixed acid temperature, pressure, etc.) in real time and send these data to the controller. After receiving the data from the sensor, the controller processes the data according to the preset control logic or algorithm, and compares the difference between the actual temperature or pressure and the set value. According to the result of data processing, the controller sends a control signal to the frequency conversion pump. If the detected temperature is higher than the set value, the controller may instruct the frequency conversion pump to increase the flow rate to improve the cooling efficiency.

[0008] Furthermore, it also includes pressure sensors arranged at the inlet and outlet of the wetted graphite plate heat exchanger for monitoring the pressure of the mixed acid and cold source circulating water, and pressure sensors arranged on the transportation pipelines of the mixed acid and cold source circulating water for monitoring the pressure changes during the transportation process.

[0009] Furthermore, the impregnated graphite plate heat exchanger is formed by stacking graphite heat exchange plates, and irregular-shaped channels are formed between the plates, and heat exchange is performed through the plates.

[0010] The technical solution adopted by the utility model has a simple connection structure, can effectively realize the recovery and utilization of heat energy, and realizes the effective recovery and utilization of mixed fluorine acid resources. It includes cold shock cooling, P membrane filter, and impregnated graphite plate heat exchanger. In order to ensure uniform feeding of hot side mixed acid, a single-loop flow control scheme is adopted, and the instantaneous flow of the mixed acid inlet is measured by an on-site remote flow meter, and the instantaneous flow of the mixed acid is compared with the process set flow. The single-loop negative feedback PID control is used to adjust the operating frequency of the mixed acid delivery pump, thereby achieving uniform feeding of the hot side mixed acid. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a diagram of exhaust gas cooling in the conventional acid roasting process of rare earth concentrate.

[0012] Figure 2 It is a schematic structural diagram of a specific embodiment of the utility model. DETAILED DESCRIPTION

[0013] The technical solution of the utility model is further explained below in conjunction with the accompanying drawings.

[0014] A tail gas cooling system in an acid roasting rare earth concentrate process comprises: a cold shock cooler 6, a primary acid circulation 1 connected to the cold shock cooler 6, a first variable frequency pump whose water inlet is arranged at the upper part of the primary acid circulation tank 11 / 2, an impregnated graphite plate heat exchanger 3 connected to the water outlet pipe of the variable frequency pump, a cold source circulation water tank 4 connected to the impregnated graphite plate heat exchanger 3 via a second variable frequency pump, and a tail gas absorption system connected to the cold source circulation water tank 4.

[0015] The tail gas absorption system includes 1-3 level absorption towers 5. A P membrane filter 2 is also provided between the primary acid circulation tank 1 and the impregnated graphite plate heat exchanger 3. It also includes a temperature sensor provided at the outlet of the impregnated graphite plate heat exchanger 3 for monitoring the temperature of the mixed acid clear liquid after cooling and a temperature sensor provided at the outlet of the mixed acid for ensuring that the mixed acid temperature drops below 60°C.

[0016] It also includes pressure sensors arranged at the inlet and outlet of the impregnated graphite plate heat exchanger for monitoring the pressure of the mixed acid and cold source circulating water, and pressure sensors arranged on the conveying pipelines of the mixed acid and cold source circulating water for monitoring the pressure change during the conveying process. The impregnated graphite plate heat exchanger is composed of stacked graphite heat exchange plates, and irregular-shaped channels are formed between the plates, through which heat exchange is performed.

[0017] It also includes a controller, which is connected to the temperature sensor, pressure sensor and variable frequency pump through cables or wireless communication. The temperature sensor and pressure sensor monitor the corresponding process parameters (such as mixed acid temperature, pressure, etc.) in real time and send these data to the controller. After receiving the data from the sensor, the controller processes the data according to the preset control logic or algorithm, and compares the difference between the actual temperature or pressure and the set value. According to the result of data processing, the controller sends a control signal to the variable frequency pump. If the detected temperature is higher than the set value, the controller may instruct the variable frequency pump to increase the flow rate to improve the cooling efficiency.

[0018] In summary, the utility model effectively utilizes the heat in the tail gas by using the impregnated graphite plate heat exchanger, realizes heat energy recovery, reduces production costs, and reduces environmental pollution, meeting environmental emission standards. In addition, the utility model effectively increases the concentration of mixed acid, improves production efficiency and economic benefits, and ensures the stability and consistency of product quality by accurately controlling the temperature and pressure of the mixed acid. The automated control system simplifies the operating process, improves operational convenience and safety, and improves energy utilization efficiency through waste heat recovery, and reduces long-term maintenance and replacement costs.

Claims

1. A tail gas cooling system in the process of acid roasting rare earth concentrate, characterized by: include: A cold shock cooler, a primary acid circulation connected to the cold shock cooler, a first variable frequency pump with a water inlet arranged at the upper 1 / 2 of the primary acid circulation tank, an impregnated graphite plate heat exchanger connected to the water outlet pipe of the variable frequency pump, a cold source circulation water tank connected to the impregnated graphite plate heat exchanger via a second variable frequency pump, and an exhaust gas absorption system connected to the cold source circulation water tank.

2. The tail gas cooling system in the acid roasting rare earth concentrate process according to claim 1, characterized in that: The tail gas absorption system includes 1-3 levels of absorption towers.

3. The tail gas cooling system in the acid roasting rare earth concentrate process according to claim 1, characterized in that: A P membrane filter is also arranged between the primary acid circulation tank and the impregnated graphite plate heat exchanger.

4. The tail gas cooling system in the acid roasting rare earth concentrate process according to claim 1, characterized in that: It also includes a temperature sensor arranged at the outlet of the soaked graphite plate heat exchanger for monitoring the temperature of the mixed acid clear liquid after cooling, and a temperature sensor arranged at the mixed acid outlet for ensuring that the mixed acid temperature drops below 60°C.

5. The tail gas cooling system in the acid roasting rare earth concentrate process according to claim 1, characterized in that: The device also includes a controller, which is connected with the temperature sensor, the pressure sensor and the variable frequency pump through cables or wireless communication.

6. The tail gas cooling system in the acid roasting rare earth concentrate process according to claim 1, characterized in that: It also includes pressure sensors arranged at the inlet and outlet of the wetted graphite plate heat exchanger for monitoring the pressure of the mixed acid and cold source circulating water, and pressure sensors arranged on the conveying pipelines of the mixed acid and cold source circulating water for monitoring the pressure changes during the conveying process.

7. The tail gas cooling system in the acid roasting rare earth concentrate process according to claim 1, characterized in that: The impregnated graphite plate heat exchanger is made of stacked graphite heat exchange plates, with irregular shaped channels formed between the plates, through which heat exchange is carried out.

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