A composite alkali production filtrate treatment system

Abstract

This invention discloses a composite alkali production filtrate treatment system, including a reaction chamber with a stirring tank at the bottom and a gas collection pipe connected to the top. The upper wall of the stirring tank has two sets of inlets: a steam inlet connected to a steam supply pipe and a waste gas inlet connected to a hot waste gas supply pipe, forming a heating zone above the liquid surface in the stirring tank. The steam supply pipe is equipped with a steam flow valve to control the amount of steam input based on the temperature of the heating zone. This invention can reduce energy consumption and water usage in industrial alkali production, and decrease the discharge of ammonia stripping wastewater.

Description

Technical Field

[0001] This utility model relates to the field of alkali production equipment technology, and in particular to a composite alkali production filtrate treatment system. Background Technology

[0002] In the industrial process of ammonia-soda production, ammonia is recovered by adding lime slurry to ammonium chloride filtrate. The ammonia stripping method is usually used, which requires a large amount of steam input. Consequently, the water consumption and energy consumption for generating steam are both large. In addition, while the steam is heating and volatilizing ammonia, some of it will also condense into the ammonia stripping waste liquid after the reaction, resulting in a large amount of waste liquid discharge. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, this utility model provides a composite alkali production filtrate treatment system, which can reduce energy consumption and resource waste in industrial alkali production, and reduce the discharge of ammonia stripping waste liquid.

[0004] Technical solution: To achieve the above objectives, this utility model provides a composite alkali production filtrate treatment system, including a reaction chamber, a stirring tank formed at the bottom of the reaction chamber, and a gas collection pipe connected to the top of the reaction chamber.

[0005] The upper cavity wall of the mixing tank is provided with two sets of inlets, including a steam interface group connected to a steam supply pipe and an exhaust gas interface group connected to a hot exhaust gas supply pipe, which can form a heating zone above the liquid surface of the mixing tank.

[0006] The steam supply pipeline is equipped with a steam flow valve, which can control the amount of steam input according to the temperature of the heating zone.

[0007] Furthermore, the exhaust gas interface group is positioned below the steam interface group to form an upper and lower stacked exhaust gas distribution zone and water vapor distribution zone in the heating zone.

[0008] Furthermore, the upper cavity wall of the heating zone contracts to form a mixing heat-generating cavity, and a spraying mechanism is provided above the mixing heat-generating cavity to form a water-spraying zone within the mixing heat-generating cavity.

[0009] Furthermore, the spraying mechanism is connected to the ammonium chloride filtrate pipeline.

[0010] Furthermore, the heating zone is equipped with a temperature sensor, which is electrically connected to the control module of the steam flow valve.

[0011] Furthermore, the hot exhaust gas supply pipeline passes through the heat exchanger, and the heat exchange tubes in the heat exchanger are connected to the heat exchange tubes in the steam generator through a connecting pipe to form a loop pipeline.

[0012] Furthermore, the hot exhaust gas supply pipeline is equipped with an exhaust gas flow valve, and the steam supply pipeline is equipped with a flow meter. Both the flow meter and the temperature sensor are electrically connected to the control module of the exhaust gas flow valve.

[0013] Furthermore, the inner ejection ends of each exhaust gas interface in the exhaust gas interface group are arranged facing upwards, and their ejection ends are located below the liquid surface of the reaction liquid in the stirring tank and close to the liquid surface.

[0014] Beneficial Effects: This utility model discloses a composite alkali production filtrate treatment system that introduces some waste heat-containing tail gas to replace water vapor, forming a composite ammonia stripping system. The input tail gas can further react with water vapor to release heat, thus significantly reducing water vapor consumption while meeting the ammonia recovery heating conditions. This further reduces water consumption and energy consumption. Furthermore, when the introduced hot waste gas is tail gas from a lime kiln, the generated Ca(OH)2 can be added to the reaction solution as a material for the ammonia recovery reaction, reducing resource waste. Additionally, it reduces the discharge of ammonia stripping waste liquid. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the system structure of one embodiment of the composite alkali production filtrate treatment system of this utility model. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings.

[0017] As attached Figure 1 The aforementioned composite alkali production filtrate treatment system includes a reaction chamber 1, a stirring tank 2 formed at the bottom of the reaction chamber 1, and a gas collection pipe 11 connected to the top of the reaction chamber 1. The reaction chamber 1 can be set inside the reaction tower. After lime slurry and ammonium chloride filtrate are added into the chamber through its own material addition port, a reaction occurs in the stirring tank at the bottom. The generated ammonia gas rises along the tower cavity and is finally collected by the gas collection pipe at the top and sent to the absorption tower for absorption, so as to realize the recovery and utilization of ammonia gas.

[0018] The upper cavity wall of the stirring tank 2 is provided with two sets of inlets, including a steam interface group 31 connected to the steam supply pipe 4 and a waste gas interface group 32 connected to the hot waste gas supply pipe 5, which can form a heating zone 3 above the liquid surface of the stirring tank 2. By introducing hot waste gas to replace part of the water vapor input, a suitable temperature environment is provided for the heating zone 3, promoting the efficient volatilization of ammonia. The heat energy in the waste gas can be recovered, reducing energy loss and reducing the amount of water vapor input, thereby reducing water consumption and energy consumption for generating water vapor. Furthermore, due to the reduced water vapor input, the amount of water condensed into the ammonia waste liquid is also reduced, resulting in a significant reduction in the amount of waste liquid generated.

[0019] The steam supply pipe 4 is equipped with a steam flow valve 41, which can control the input amount of water vapor according to the temperature of the heating zone 3. Only a portion of the hot exhaust gas is drawn from the original discharge pipe and transported into the reaction chamber. Initially, both water vapor and hot exhaust gas are input at a single initial flow rate. When the temperature in the heating zone is too high, the input amount of water vapor can be further reduced by adjusting the steam flow valve.

[0020] Preferably, the hot exhaust gas supply pipe 5 is connected to the tail gas discharge pipe of the lime kiln, which can introduce a portion of the lime kiln tail gas into the reaction chamber.

[0021] The exhaust gas interface group 32 is positioned lower than the steam interface group 31, forming a stacked tail gas distribution zone and a steam distribution zone in the heating zone 3. The upper cavity wall of the heating zone 3 contracts to form a mixing and heat-generating chamber 6. A spraying mechanism 7 is provided above the mixing and heat-generating chamber 6, which can form a water spraying zone within the mixing and heat-generating chamber 6. This allows the introduced tail gas to rise and pass through the steam distribution zone, entering the mixing and heat-generating chamber 6 in a mixed state. Since the tail gas of the lime kiln contains residual CaO particles, when it comes into contact with steam, it can react to produce Ca(OH)2 and release a certain amount of heat. When the tail gas passes through the spraying zone, most of the heat can be intercepted and retained in the lower part of the reaction chamber. By generating heat through the reaction of residual substances in the tail gas, the amount of steam input can be further reduced. The Ca(OH)2 produced by the reaction will fall into the stirring tank below with the water spraying to participate in the ammonia generation reaction, which can effectively improve the utilization rate of limestone, the raw material for alkali production, and reduce resource consumption.

[0022] The spraying mechanism 7 is connected to the ammonium chloride filtrate pipeline 8. The ammonium chloride filtrate is added to the reaction chamber by spraying, which allows it to exchange heat with the rising exhaust gas water vapor mixture during the descent process, and preferentially reacts with the falling Ca(OH)2 to produce ammonia. The ammonia produced at this time is easier to separate from the liquid phase, which facilitates the recovery of ammonia.

[0023] Example: The heating zone 3 is equipped with a temperature sensor 33, which is electrically connected to the control module of the steam flow valve 41. The hot exhaust gas supply pipe 5 passes through the heat exchanger 9, and the heat exchange tubes in the heat exchanger 9 are connected to the heat exchange tubes in the steam generator 10 through connecting pipes to form a loop pipeline. The hot exhaust gas supply pipe 5 is equipped with an exhaust gas flow valve 51, and the steam supply pipe 4 is equipped with a flow meter. Both the flow meter and the temperature sensor 33 are electrically connected to the control module of the exhaust gas flow valve 51. When the temperature in the heating zone exceeds a preset range, the input of water vapor can be reduced first. A minimum water vapor input value is preset. When the water vapor decreases to this minimum input value, the input of exhaust gas is further reduced to ensure that the temperature of the reaction solution is maintained within the preset range. This effectively reduces the amount of water vapor used while ensuring stable ammonia volatilization.

[0024] The introduced exhaust gas is first used to heat water to generate water vapor through heat exchange, which can remove a large amount of heat. Then, the exhaust gas with a suitable residual temperature is transported into the reaction chamber to avoid the exhaust gas temperature being too high and affecting the ammonia recovery effect.

[0025] Preferably, the inner ejector ends of each exhaust gas interface in the exhaust gas interface group 32 are arranged facing upwards, and their ejector ends are located below and close to the surface of the reaction liquid in the stirring tank 2. This allows the reaction solution near the liquid surface to be blown upwards by the airflow to form droplets, which are more easily exposed to high-temperature gas, thereby accelerating the volatilization of ammonia from the solution.

[0026] The above are merely preferred embodiments of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A composite alkali production filtrate treatment system, characterized in that: It includes a reaction chamber (1), a stirring tank (2) is formed at the bottom of the reaction chamber (1), and a gas collection pipe (11) is connected to the top of the reaction chamber (1). The upper cavity wall of the stirring tank (2) is provided with two sets of inlets, including a steam interface group (31) connected to the steam supply pipe (4) and a waste gas interface group (32) connected to the hot waste gas supply pipe (5), which can form a heating zone (3) above the liquid surface of the stirring tank (2). The steam supply pipe (4) is equipped with a steam flow valve (41) which can control the amount of steam input according to the temperature of the heating zone (3).

2. The composite alkali production filtrate treatment system according to claim 1, characterized in that: The exhaust gas interface group (32) is positioned below the steam interface group (31) to form an upper and lower stacked exhaust gas distribution zone and water vapor distribution zone in the heating zone (3).

3. The composite alkali production filtrate treatment system according to claim 2, characterized in that: The upper cavity wall of the heating zone (3) contracts to form a mixed heat generation cavity (6), and a spraying mechanism (7) is provided above the mixed heat generation cavity (6) to form a water spraying zone in the mixed heat generation cavity (6).

4. The composite alkali production filtrate treatment system according to claim 3, characterized in that: The spraying mechanism (7) is connected to the ammonium chloride filtrate pipeline (8).

5. The composite alkali production filtrate treatment system according to claim 1, characterized in that: The heating zone (3) is equipped with a temperature sensor (33), which is electrically connected to the control module of the steam flow valve (41).

6. The composite alkali production filtrate treatment system according to claim 5, characterized in that: The hot exhaust gas supply pipe (5) passes through the heat exchanger (9), and the heat exchange tube in the heat exchanger (9) is connected to the heat exchange tube in the steam generator (10) through a connecting pipe to form a loop pipeline.

7. The composite alkali production filtrate treatment system according to claim 6, characterized in that: The hot exhaust gas supply pipe (5) is equipped with an exhaust gas flow valve (51), and the steam supply pipe (4) is equipped with a flow meter. The flow meter and the temperature sensor (33) are both electrically connected to the control module of the exhaust gas flow valve (51).

8. The composite alkali production filtrate treatment system according to claim 7, characterized in that: The inner ejection ends of each exhaust gas interface in the exhaust gas interface group (32) are arranged facing upwards, and their ejection ends are located below the liquid surface of the reaction liquid in the stirring tank (2) and close to the liquid surface.

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