Efficient ammonia absorption system in ammonia synthesis process and control method thereof
By combining a two-stage absorption tower with an intelligent control device, the problems of low ammonia absorption efficiency and poor stability in the ammonia synthesis process have been solved, achieving efficient ammonia absorption and stable system operation, and reducing energy consumption and production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAN THERMAL POWER RES INST CO LTD
- Filing Date
- 2026-03-19
- Publication Date
- 2026-05-15
AI Technical Summary
The existing ammonia absorption system in the ammonia synthesis process suffers from low absorption efficiency, poor operational stability, and inaccurate control. In particular, it is difficult to adapt to fluctuations in inlet flow rate and concentration, resulting in raw material waste and high energy consumption.
The system employs a two-stage absorption tower connected in series, combined with an intelligent control device, including pretreatment, rotary and atomizing spray heads, temperature, pressure and ammonia concentration sensors. By real-time monitoring and automatic adjustment of spray volume and heating power, it achieves efficient ammonia absorption and system stability.
It improved ammonia absorption efficiency to 99%, reduced ammonia content in exhaust gas, reduced absorbent consumption and energy consumption, ensured stable system operation and precise control, and reduced production costs.
Smart Images
Figure CN122032272A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of synthetic ammonia production technology, specifically relating to a high-efficiency ammonia absorption system and its control method in ammonia synthesis process. Background Technology
[0002] Ammonia synthesis is a crucial basic product in the chemical industry, and its production process involves multiple stages, with ammonia absorption being one of the core steps. In the ammonia synthesis process, the resulting gas mixture typically contains ammonia, hydrogen, nitrogen, and other impurities, requiring absorption to separate and recover the ammonia from the mixture. The efficiency of ammonia absorption directly affects the yield, purity, and production cost of ammonia, and also influences whether exhaust emissions meet standards. Currently, commonly used industrial ammonia absorption systems employ absorption tower structures, where an absorbent (such as water, dilute acid, or a specialized absorbent) comes into countercurrent contact with the ammonia-containing gas, dissolving the ammonia in the absorbent.
[0003] However, existing ammonia absorption systems still have many shortcomings. First, many systems use single-tower absorption, resulting in limited gas-liquid contact time and low mass transfer efficiency, leading to low ammonia absorption rates and high residual ammonia concentrations in the tail gas. This wastes raw materials and increases the burden on subsequent environmental treatment. Second, while some multi-tower series systems improve absorption efficiency to some extent, poor coordination between towers and a lack of a unified control mechanism make it difficult to adapt to fluctuations in inlet flow rate, concentration, and other operating conditions. This results in poor system stability and a tendency for problems such as fluctuations in absorption efficiency or even flooding of the absorbent liquid.
[0004] Furthermore, existing systems typically employ a desorption tower for heating and desorption during the absorbent regeneration process. However, directly returning the high-temperature absorbent to the tower after desorption reduces absorption efficiency, while traditional cooling methods lack precise control and consume significant energy. In terms of control, most systems rely on manual experience or simple automatic control, such as single-loop PID regulation. This results in insufficient monitoring of key parameters like temperature, pressure, level, and concentration within the tower, leading to lag in regulation and an inability to achieve real-time optimization, resulting in slow system response and high energy consumption. The pretreatment stage is also frequently overlooked. If impurities such as solid particles, oil mist, and moisture carried in ammonia-containing gas are not effectively removed, they can clog the packing material, contaminate the absorbent, and affect absorption efficiency and equipment lifespan. Summary of the Invention
[0005] The purpose of this invention is to overcome the problems of low absorption efficiency, poor operational stability, and imprecise control in existing ammonia absorption systems, and to provide a high-efficiency ammonia absorption system and its control method in the ammonia synthesis process, so as to improve ammonia absorption efficiency, enhance system operational stability, achieve precise control, and reduce production costs.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a high-efficiency ammonia absorption system for ammonia synthesis process, comprising a pretreatment device, a primary absorption tower, a secondary absorption tower, a stripping tower, and an intelligent control device; The outlet of the pretreatment device is connected to the ammonia-containing gas inlet of the primary absorption tower; the primary absorption tower is equipped with a first spray device, the gas outlet of the primary absorption tower is connected to the gas inlet of the secondary absorption tower, and the absorbent outlet of the primary absorption tower is connected to the inlet of the desorption tower; the secondary absorption tower is equipped with a second spray device, and the absorbent outlet of the secondary absorption tower is connected to the first spray device. The outlet of the analytical column is connected to the first spray device and the second spray device respectively, and a cooler is provided on the connecting pipeline; The intelligent control device includes several sensors and a controller; the sensors are respectively installed on the primary absorption tower, the secondary absorption tower, and the pipeline through which the absorbent flows; the controller is electrically connected to the sensors, the first spray device, the second spray device, and the heating device of the desorption tower.
[0007] A further improvement of the present invention is that the pretreatment device includes a filter and a dryer, the inlet of the filter is connected to an ammonia-containing gas source, the outlet of the filter is connected to the inlet of the dryer, and the outlet of the dryer is connected to the ammonia-containing gas inlet of the primary absorption tower.
[0008] A further improvement of the present invention is that the filter is a precision cartridge filter, the dryer is an adsorption dryer, and the adsorption dryer contains a molecular sieve desiccant.
[0009] A further improvement of the present invention is that the first spraying device is a rotary spray head, and the second spraying device is an atomizing spray head.
[0010] A further improvement of the present invention is that the primary absorption tower is further provided with a first packing layer, which is located below the first spraying device; and the secondary absorption tower is further provided with a second packing layer, which is located below the second spraying device.
[0011] A further improvement of the present invention is that an ammonia outlet is provided at the top of the analysis tower; and the heating device for the analysis tower is a steam coil installed at the bottom of the analysis tower.
[0012] A further improvement of the present invention is that the intelligent control device includes a temperature sensor, a pressure sensor, an ammonia concentration sensor, and a flow sensor; the temperature sensor, pressure sensor, and ammonia concentration sensor are respectively installed inside the primary absorption tower and the secondary absorption tower, and the flow sensor is installed on the pipeline through which the absorbent flows.
[0013] Secondly, the present invention also provides a control method based on the above system, comprising the following steps: S1, Start the system: Turn on the pretreatment device, and at the same time start the first spray device and the second spray device, so that the absorbent liquid enters the first-stage absorption tower and the second-stage absorption tower respectively, and at the same time, ammonia-containing gas is introduced into the pretreatment device. S2, Parameter setting: The target temperature range, target pressure range, and target ammonia concentration in the tail gas of the secondary absorption tower are set by the controller. S3, Real-time monitoring: The temperature, pressure, ammonia concentration, and flow rate of the absorbent in the primary and secondary absorption towers are monitored in real time using temperature sensors, pressure sensors, ammonia concentration sensors, and flow sensors, and the monitoring data is transmitted to the controller in real time. S4, Control and Adjustment: The controller compares the received detection data with the set target value, and adjusts at least one of the following according to the comparison result: the absorbent flow rate of the first spray device, the absorbent flow rate of the second spray device, and the power of the heating device of the desorption tower.
[0014] A further improvement of the present invention is that, in the control and regulation step, when the ammonia concentration in the tail gas of the secondary absorption tower exceeds the target concentration, the controller increases the flow rate of the absorbent liquid of the second spray device.
[0015] A further improvement of the present invention is that, in the control and adjustment step, when the temperature inside the primary absorption tower is higher than the target temperature range, the controller increases the cooling intensity of the cooler; when the temperature inside the primary absorption tower is lower than the target temperature range, the controller decreases the cooling intensity of the cooler.
[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention employs a two-stage absorption tower structure connected in series. Ammonia-containing gas is sequentially absorbed by spraying in both a primary and secondary absorption towers, significantly improving ammonia absorption efficiency and effectively reducing the ammonia content in the exhaust gas. The absorbent outlet of the secondary absorption tower is connected to the first spray device of the primary absorption tower, allowing a portion of the absorbent to be recycled back to the primary tower, reducing absorbent consumption and lowering the processing load on the desorption tower. The desorption liquid outlet of the desorption tower is connected to the spray devices of both absorption towers via coolers, achieving the recycling and reuse of the absorbent, saving resources and meeting energy conservation and environmental protection requirements. Simultaneously, the intelligent control device monitors system operating parameters in real time through various sensors, and the controller automatically adjusts the spray volume of the first and second spray devices and the heating power of the desorption tower heating device based on the monitoring data, ensuring the system is always in optimal working condition. This guarantees operational stability and control precision, reduces manual intervention, and improves production efficiency.
[0017] This invention also provides a control method for a high-efficiency ammonia absorption system in a synthetic ammonia process. After system startup, the method uses a controller to pre-set the temperature and pressure ranges within the absorption tower and the target ammonia concentration in the tail gas, providing a clear control benchmark for system operation. Key parameters during system operation are collected in real time by various sensors and transmitted to the controller. The controller compares and analyzes the real-time monitoring data with the set target values and automatically adjusts the absorbent flow rates of the first and second spray devices and the heating power of the desorption tower heating device based on deviations, ensuring the system always maintains optimal operating conditions. This control method achieves automated and precise control of the ammonia absorption process, avoiding the lag and instability of manual operation. It can respond in real time to changes in the inlet gas conditions, ensuring stable and compliant ammonia absorption efficiency. Furthermore, by adjusting the spray volume and heating power as needed, it avoids energy and absorbent waste, reducing system operating costs. Attached Figure Description
[0018] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components of the invention.
[0019] Figure 1 This is a schematic diagram of the structure of the high-efficiency ammonia absorption system in the ammonia synthesis process of this invention.
[0020] The components include: 1. Pretreatment device; 11. Filter; 12. Dryer; 2. Primary absorption tower; 21. First packing layer; 22. First spray device; 3. Secondary absorption tower; 31. Second packing layer; 32. Second spray device; 4. Desorption tower; 5. Cooler. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.
[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0024] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0025] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0026] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.
[0027] The present invention will now be described in further detail with reference to the accompanying drawings: like Figure 1 As shown, the present invention provides a high-efficiency ammonia absorption system in ammonia synthesis process, including a pretreatment device 1, a primary absorption tower 2, a secondary absorption tower 3, a stripping tower 4, and an intelligent control device.
[0028] The pretreatment device 1 includes a filter 11 and a dryer 12. The inlet of the filter 11 is connected to an ammonia-containing gas source, and the outlet of the filter 11 is connected to the inlet of the dryer 12. The outlet of the dryer 12 is connected to the ammonia-containing gas inlet of the primary absorption tower 2. Through this connection, the ammonia-containing gas is filtered to remove solid impurities and moisture before entering the absorption tower, which prevents impurities from clogging the packing and contaminating the absorption liquid, while avoiding moisture affecting the absorption effect, thereby ensuring the stability and efficiency of the subsequent absorption process.
[0029] The primary absorption tower 2 is equipped with a first packing layer 21 and a first spray device 22 located above the first packing layer 21. The first spray device 22 is a rotary spray head. The ammonia-containing gas inlet of the primary absorption tower 2 is connected to the outlet of the pretreatment device 1. The ammonia-containing gas inlet is located on the side of the bottom of the primary absorption tower 2 and is connected to the outlet of the dryer 12 of the pretreatment device 1 via a flange. The gas outlet is connected to the gas inlet of the secondary absorption tower 3, and the absorbent liquid outlet is connected to the inlet of the desorption tower 4. The first packing layer 21 increases the gas-liquid contact area, and the rotary spray head can evenly spray the absorbent liquid onto the first packing layer 21, promoting the full dissolution of ammonia. The rich liquid at the bottom of the tower flows into the desorption tower 4 for regeneration, realizing the recycling of the absorbent liquid.
[0030] The secondary absorption tower 3 is equipped with a second packing layer 31 and a second spray device 32 located above the second packing layer 31. The second spray device 32 is an atomizing spray head. The gas inlet of the secondary absorption tower 3 is connected to the gas outlet of the primary absorption tower 2. It has a tail gas outlet at the top and an absorbent outlet at the bottom connected to the first spray device 22 of the primary absorption tower 2 via a pipeline. The atomizing spray head generates fine droplets, further increasing the gas-liquid contact surface area and enabling deep absorption of residual ammonia. Part of the absorbent at the bottom of the secondary absorption tower 3 is returned to the primary absorption tower 2 as a supplementary absorbent, which can improve the utilization rate of the absorbent and reduce the desorption load.
[0031] The analytical tower 4 is used to analyze the absorbent and recover ammonia. It has an ammonia outlet at the top, connected to an ammonia storage tank for storing the recovered ammonia. At the bottom, it has an analytical liquid outlet connected to a cooler 5 via a pipe. The cooler 5 is a water-cooled heat exchanger that cools the analytical liquid to 30-40°C before it is conveyed to the first spray device 22 of the primary absorption tower 2 and the second spray device 32 of the secondary absorption tower 3. The heating device for the analytical tower 4 is a steam coil located at the bottom. The steam coil heats the rich liquid to extract high-purity ammonia. The high-temperature absorbent liquid after analysis is cooled by the cooler 5 before returning to the absorption tower, preventing a decrease in absorption efficiency due to excessive temperature and ensuring the normal operation of the spray devices.
[0032] The intelligent control device includes a temperature sensor, a pressure sensor, an ammonia concentration sensor, a flow sensor, and a controller. The temperature sensor, pressure sensor, and ammonia concentration sensor are respectively installed inside the primary absorption tower 2 and the secondary absorption tower 3. The flow sensor is installed on the pipeline through which the absorbent flows (including the pipeline connecting the desorption tower 4 and the spray device, as well as the secondary tower reflux pipeline, etc.). The controller is electrically connected to each of the above sensors, the first spray device 22, the second spray device 32, and the heating device of the desorption tower 4. By collecting the operating parameters inside the tower in real time through the sensors, the controller can automatically adjust the spray volume, heating power, etc., according to preset values to ensure that the system always operates in the optimal state, maximizing absorption efficiency while reducing energy consumption.
[0033] As a preferred option, filter 11 uses a precision filter cartridge, which can effectively remove solid impurities from ammonia-containing gas; the dryer uses an adsorption dryer, which is filled with molecular sieve desiccant, and can reduce the moisture content in the gas to below 5 ppm.
[0034] As a preferred option, the first packing layer 21 of the primary absorption tower 2 uses Pall ring packing, which has a large specific surface area and good gas-liquid contact performance.
[0035] As a preferred option, the second packing layer 31 of the secondary absorption tower 3 adopts stepped ring packing, which has high mass transfer efficiency.
[0036] The present invention also provides a control method based on the above system, comprising the following steps: S1, Start the system: Turn on the pretreatment device 1, and at the same time start the first spray device 22 and the second spray device 32, so that the absorbent liquid enters the first-stage absorption tower 2 and the second-stage absorption tower 3 respectively, and at the same time, ammonia-containing gas is introduced into the pretreatment device 1. S2, Parameter setting: The target temperature range, target pressure range, and target ammonia concentration in the tail gas of the secondary absorption tower 3 are set by the controller. S3, Real-time monitoring: The temperature, pressure, ammonia concentration, and flow rate of the absorbent liquid in the primary absorption tower 2 and the secondary absorption tower 3 are monitored in real time by temperature sensors, pressure sensors, ammonia concentration sensors, and flow sensors, and the monitoring data is transmitted to the controller in real time. S4, Control and Adjustment: The controller compares the received detection data with the set target value, and adjusts at least one of the absorption liquid flow rate of the first spray device 22, the absorption liquid flow rate of the second spray device 32, and the heating device power of the desorption tower 4 according to the comparison result to ensure that the ammonia absorption efficiency meets the standard.
[0037] In the control and regulation steps, when the ammonia concentration in the tail gas of the secondary absorption tower 3 exceeds the target concentration, the controller increases the absorbent flow rate of the second spray device 32; if it still cannot meet the target, the absorbent flow rate of the primary absorption tower 2 is increased.
[0038] In the control and regulation steps, when the temperature inside the primary absorption tower 2 is higher than the target temperature range, the controller increases the cooling intensity of the cooler 5; when the temperature inside the primary absorption tower 2 is lower than the target temperature range, the controller decreases the cooling intensity of the cooler 5.
[0039] In the control and regulation step, when the pressure inside the primary absorption tower 2 deviates from the target pressure range, the controller adjusts the inlet valve on the ammonia-containing gas inlet pipe of the primary absorption tower 2, or adjusts the exhaust valve on the gas outlet pipe of the primary absorption tower 2, so that the pressure returns to the target range.
[0040] In actual operation, ammonia-containing gas first enters the pretreatment unit 1, where solid impurities are removed by filter 11, and moisture is removed by dryer 12 before entering the primary absorption tower 2. Inside the primary absorption tower 2, the ammonia-containing gas comes into full contact with the absorbent sprayed by the first spray device 22 in the first packing layer 21, and most of the ammonia is absorbed. Unabsorbed gas exits from the top of the primary absorption tower 2 and enters the secondary absorption tower 3, where it comes into contact again with the absorbent sprayed by the second spray device 32 in the second packing layer 31, further absorbing ammonia. The purified tail gas exits from the top of the secondary absorption tower 3. The absorbent liquid (rich liquid) at the bottom of the primary absorption tower 2 enters the desorption tower 4, where it undergoes heating and desorption, releasing high-purity ammonia gas, which enters the ammonia storage tank from the ammonia outlet at the top of the desorption tower 4. The desorbed liquid is cooled by cooler 5 and then sent to the spray devices of the primary absorption tower 2 and the secondary absorption tower 3 for recycling. The sensors of the intelligent control device monitor relevant parameters in real time and transmit the data to the PLC controller. The PLC controller adjusts each device according to the set target values. Using the system and control method of this invention, the ammonia absorption efficiency can reach over 99%, the system operates stably, and energy consumption is reduced by 15%-20%.
[0041] Many embodiments and applications beyond the examples provided will be apparent to those skilled in the art upon reading the foregoing description. Therefore, the scope of this teaching should not be determined by reference to the foregoing description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.
[0042] The above content provides a further detailed description of the present invention. It should not be construed that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered as falling within the scope of protection of the present invention as defined by the submitted claims.
Claims
1. A high-efficiency ammonia absorption system for ammonia synthesis process, characterized in that, It includes a pretreatment device (1), a primary absorption tower (2), a secondary absorption tower (3), a desorption tower (4), and an intelligent control device; The outlet of the pretreatment device (1) is connected to the ammonia-containing gas inlet of the primary absorption tower (2); the primary absorption tower (2) is equipped with a first spray device (22), the gas outlet of the primary absorption tower (2) is connected to the gas inlet of the secondary absorption tower (3), and the absorbent outlet of the primary absorption tower (2) is connected to the inlet of the desorption tower (4); the secondary absorption tower (3) is equipped with a second spray device (32), and the absorbent outlet of the secondary absorption tower (3) is connected to the first spray device (22); The outlet of the analytical tower (4) is connected to the first spray device (22) and the second spray device (32) respectively, and a cooler (5) is provided on the connecting pipeline. The intelligent control device includes several sensors and a controller; the several sensors are respectively installed on the primary absorption tower (2), the secondary absorption tower (3) and the pipeline through which the absorbent flows; the controller is electrically connected to the several sensors, the first spray device (22), the second spray device (32) and the heating device of the analytical tower (4).
2. The high-efficiency ammonia absorption system in a synthetic ammonia process according to claim 1, characterized in that, The pretreatment device (1) includes a filter (11) and a dryer (12). The inlet of the filter (11) is connected to an ammonia-containing gas source, and the outlet of the filter (11) is connected to the inlet of the dryer (12). The outlet of the dryer (12) is connected to the ammonia-containing gas inlet of the primary absorption tower (2).
3. The high-efficiency ammonia absorption system in a synthetic ammonia process according to claim 2, characterized in that, The filter (11) is a precision filter cartridge filter, and the dryer (12) is an adsorption dryer containing molecular sieve desiccant.
4. The high-efficiency ammonia absorption system in a synthetic ammonia process according to claim 1, characterized in that, The first spray device (22) is a rotary spray head, and the second spray device (32) is an atomizing spray head.
5. The high-efficiency ammonia absorption system in a synthetic ammonia process according to claim 1, characterized in that, The first-stage absorption tower (2) is also provided with a first packing layer (21), which is located below the first spray device (22); the second-stage absorption tower (3) is also provided with a second packing layer (31), which is located below the second spray device (32).
6. The high-efficiency ammonia absorption system in a synthetic ammonia process according to claim 1, characterized in that, The top of the analysis tower (4) is provided with an ammonia outlet, and the heating device of the analysis tower (4) is a steam coil installed at the bottom of the analysis tower (4).
7. The high-efficiency ammonia absorption system in a synthetic ammonia process according to claim 1, characterized in that, The intelligent control device includes a temperature sensor, a pressure sensor, an ammonia concentration sensor, and a flow sensor; the temperature sensor, pressure sensor, and ammonia concentration sensor are respectively installed inside the primary absorption tower (2) and the secondary absorption tower (3), and the flow sensor is installed on the pipeline through which the absorbent flows.
8. A control method based on the system according to any one of claims 1-7, characterized in that, Includes the following steps: S1, Start the system: Turn on the pretreatment device (1), and at the same time start the first spray device (22) and the second spray device (32) so that the absorbent liquid enters the first-stage absorption tower (2) and the second-stage absorption tower (3) respectively, and at the same time, ammonia-containing gas is introduced into the pretreatment device (1); S2, Parameter setting: Set the target temperature range, target pressure range and target ammonia concentration in the tail gas of the primary absorption tower (2) and the secondary absorption tower (3) through the controller; S3, Real-time monitoring: The temperature, pressure, ammonia concentration and flow rate of the absorbent liquid in the primary absorption tower (2) and the secondary absorption tower (3) are detected in real time by several sensors, and the detection data is transmitted to the controller in real time. S4, Control and Adjustment: The controller compares the received detection data with the set target value, and adjusts at least one of the following according to the comparison result: the absorption liquid flow rate of the first spray device (22), the absorption liquid flow rate of the second spray device (32), and the heating device power of the desorption tower (4).
9. The control method according to claim 8, characterized in that, In the control and regulation step, when the ammonia concentration in the tail gas of the secondary absorption tower (3) exceeds the target concentration, the controller increases the absorption liquid flow rate of the second spray device (32).
10. The control method according to claim 8, characterized in that, In the control and regulation steps, when the temperature inside the primary absorption tower (2) is higher than the target temperature range, the controller increases the cooling intensity of the cooler (5); when the temperature inside the primary absorption tower (2) is lower than the target temperature range, the controller decreases the cooling intensity of the cooler (5).