Method for recovering and recycling ammonia-containing tail gas in sodium carbonate production

Abstract

The invention relates to the technical field of chemical waste gas treatment, and discloses a method for recovering and recycling ammonia-containing tail gas in sodium carbonate production, which is applied to a tail gas treatment system comprising a condensing unit, a washing unit and a demisting unit which are communicated in sequence. The process comprises the following steps: configuring a multiphase flow state monitoring module, collecting temperature, pressure and relative humidity data in real time, and calculating a crystallization chemical potential value reflecting an ammonium salt solid phase generation trend, a phase change lag index reflecting a liquid-solid conversion ratio of aerosol particles in a turbulent flow environment and a liquid holding load value of a demister; establishing a multi-parameter coupling control index associated with the parameters and the periodic spacing value of the sedimentary layer; and executing a multivariable linkage adjustment strategy according to the index, and performing dynamic balance adjustment on the flow of the cooling medium, the washing circulating liquid and the demisting flushing liquid.

Description

Technical Field

[0001] This invention relates to the field of chemical waste gas treatment technology, and more specifically, to a method for the recovery and resource utilization of ammonia-containing tail gas in soda ash production. Background Technology

[0002] In the ammonia-soda process for producing soda ash, the carbonation tower and subsequent filtration and washing sections generate a large amount of ammonia-containing tail gas. This tail gas not only contains unreacted ammonia but also high concentrations of carbon dioxide and saturated water vapor. To recover valuable ammonia resources and meet increasingly stringent environmental emission standards, industry typically employs a series of processes: condensation cooling → acid / water washing → mechanical demisting. Among these, wire mesh demisters or baffle demisters are widely used to capture tiny droplets entrained in the gas flow, preventing ammonia salt aerosols from being released into the atmosphere. However, in actual engineering operations, the aforementioned traditional treatment processes face complex multiphase flow stability issues, mainly manifested in the following two aspects:

[0003] First, existing control logic is mostly based on single temperature or pressure feedback. For example, maintaining the outlet temperature at a set value by adjusting the cooling water flow rate, or judging whether the equipment is blocked by monitoring the pressure difference. However, in the ammonia-carbon dioxide-water ternary system, there is significant reactive crystallization behavior. When the partial pressure product of ammonia and carbon dioxide in the gas phase reaches a certain threshold, even if the temperature has not dropped below the dew point, ammonium bicarbonate solid may be directly generated through gas-solid reaction. Traditional temperature control strategies cannot detect this crystallization-driven trend, resulting in unpredictable rapid scaling on the surface of heat exchangers and the inner walls of pipes, forcing unplanned shutdowns for cleaning. Second, for suspended salt aerosols in the exhaust gas, existing technologies often simply treat them as ordinary droplets for collection. In fact, inorganic salt particles exhibit significant phase hysteresis during moisture absorption and drying (i.e., the deliquescence point and efflorescence point do not coincide). Inside the demister, the airflow is in a state of high-intensity turbulence, and the local relative humidity fluctuates rapidly. This fluctuation drives the particles attached to the mesh to repeatedly transform between droplets and solid crystal shells.

[0004] This repeated phase transition leads to the formation of a unique depositional structure: dense crystalline shells and loose, powdery layers stacked alternately. This non-uniform depositional structure not only causes irregular drift in the demister's operating resistance but also leads to periodic fluctuations in capture efficiency. When the loose layer collapses under the impact of airflow, it causes a transient ammonia escape peak, and such short-term emission exceedances are often difficult for online monitoring systems based on long-term average values ​​to detect and suppress in a timely manner. Summary of the Invention

[0005] This invention provides a method for the recovery and resource utilization of ammonia-containing tail gas in soda ash production, which solves the technical problems mentioned in the background art.

[0006] In a first aspect, a method for recovering and utilizing ammonia-containing tail gas in soda ash production is provided, which is applied to a tail gas treatment system comprising a condensation unit, a washing unit, and a demisting unit connected in sequence, comprising:

[0007] A multiphase flow state monitoring module is configured to collect process gas temperature, pressure and relative humidity data at the condensation unit and the demisting unit, and to calculate the crystallization chemical potential energy value reflecting the trend of ammonium salt solid phase formation, the aerosol phase transformation hysteresis index reflecting the liquid-solid conversion ratio of aerosol particles in turbulent environment, and the demister liquid holding load value calculated based on the wet operation pressure difference of the demisting unit.

[0008] Establish a multi-parameter correlation control index that includes the crystallization chemical potential energy value, aerosol phase transformation hysteresis index, demister liquid holding load value, deposition layer periodic spacing value and outlet ammonia concentration deviation value.

[0009] Based on the multi-parameter correlation control index, a multi-variable linkage adjustment strategy is executed to dynamically balance and adjust the cooling medium flow rate of the condensation unit, the circulating liquid flow rate of the washing unit, and the flushing liquid flow rate of the demisting unit, so as to control the microstructure of the deposits inside the demisting unit and maintain the periodic spacing value of the deposit layer within a preset range.

[0010] Secondly, a system for recovering and recycling ammonia-containing tail gas in soda ash production, comprising the steps of a method for recovering and recycling ammonia-containing tail gas in soda ash production as described in any one of the claims, including:

[0011] The exhaust gas treatment host includes a condensation unit, a washing unit and a demisting unit connected sequentially by pipelines along the flow direction of the process gas. The condensation unit, washing unit and demisting unit are respectively equipped with a cooling medium flow regulating mechanism, a circulating liquid flow regulating mechanism and a flushing liquid flow regulating mechanism.

[0012] A multiphase flow state monitoring network is deployed at the condensation unit and the demisting unit to collect process gas temperature, pressure and relative humidity data in real time.

[0013] The intelligent control center is communicatively connected to the multiphase flow state monitoring network and the exhaust gas treatment host. The intelligent control center includes a processor and a memory. The memory stores a computer program, and the processor executes the computer program to perform the following operations:

[0014] The state calculation logic is invoked to calculate the crystallization chemical potential energy value reflecting the trend of ammonium salt solid phase formation, the aerosol phase transformation hysteresis index reflecting the liquid-solid conversion ratio of aerosol particles in turbulent environment, and the demister liquid holding load value calculated based on the wet operation pressure difference of the demister unit.

[0015] The indicator construction logic is invoked to establish a multi-parameter correlation control index that includes the crystallization chemical potential energy value, aerosol phase transformation hysteresis index, demister liquid holding load value, deposition layer periodic spacing value and outlet ammonia concentration deviation value.

[0016] The linkage adjustment logic is invoked to generate a multivariable linkage adjustment command based on the multi-parameter correlation control index, and sent to the cooling medium flow rate adjustment mechanism, the circulating fluid flow rate adjustment mechanism, and the flushing fluid flow rate adjustment mechanism to dynamically balance and adjust the cooling medium flow rate, the circulating fluid flow rate, and the flushing fluid flow rate, thereby controlling the microstructure of the deposits inside the demisting unit and maintaining the periodic spacing value of the deposit layer within a preset range.

[0017] Thirdly, a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for the recovery and resource utilization of ammonia-containing tail gas in soda ash production as described in any one of the claims.

[0018] The beneficial effects of this invention are as follows: By constructing a multi-parameter coupled control model that includes crystallization chemical potential energy, aerosol phase transition hysteresis index and demister liquid holding load, the defects of traditional temperature control strategies that cannot perceive gas-solid reaction trends and micro-phase evolution are overcome, and active intervention in the microstructure of deposits inside the demister unit is realized; This invention can effectively suppress the formation of dense crystal shells and guide deposits to maintain a loose morphology that is easy to wash, thereby eliminating the periodic oscillation phenomenon of collection efficiency caused by turbulent environment, significantly extending the long-term stable operation time of the device, and increasing the resource recovery concentration of tail gas scrubbing liquid while reducing the ammonia slip peak. Attached Figure Description

[0019] Figure 1 This is a flowchart of a method for recovering and recycling ammonia-containing tail gas in soda ash production according to the present invention.

[0020] Figure 2 This is a schematic diagram illustrating a specific implementation of the present invention. Detailed Implementation

[0021] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0022] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of the present invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in one or more embodiments of the present invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" indicate that the element or object preceding the term encompasses the elements or objects listed following the term and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] Example 1: As Figure 1 As shown, a method for recovering and utilizing ammonia-containing tail gas in soda ash production is applied to a tail gas treatment system comprising a condensation unit, a scrubbing unit, and a demister unit connected in sequence, including:

[0024] A multiphase flow state monitoring module is configured to collect process gas temperature, pressure and relative humidity data at the condensation unit and the demisting unit, and to calculate the crystallization chemical potential energy value reflecting the trend of ammonium salt solid phase formation, the aerosol phase transformation hysteresis index reflecting the liquid-solid conversion ratio of aerosol particles in turbulent environment, and the demister liquid holding load value calculated based on the wet operation pressure difference of the demisting unit.

[0025] Establish a multi-parameter correlation control index that includes the crystallization chemical potential energy value, aerosol phase transformation hysteresis index, demister liquid holding load value, deposition layer periodic spacing value and outlet ammonia concentration deviation value.

[0026] Based on the multi-parameter correlation control index, a multi-variable linkage adjustment strategy is executed to dynamically balance and adjust the cooling medium flow rate of the condensation unit, the circulating liquid flow rate of the washing unit, and the flushing liquid flow rate of the demisting unit, so as to control the microstructure of the deposits inside the demisting unit and maintain the periodic spacing value of the deposit layer within a preset range.

[0027] Preferably, the calculation formula for the crystallization chemical potential energy value, which reflects the tendency of ammonium salt solid phase formation, is as follows:

[0028]

[0029] in, This represents the chemical potential energy for crystallization. , , These are the partial pressures of ammonia, carbon dioxide, and water vapor in the process gas, respectively.

[0030] The equilibrium constraint function for solid-state generation is defined as follows:

[0031]

[0032] The equivalent temperature of the gas-liquid interface is given by the following formula:

[0033]

[0034] In the formula, The outlet gas temperature of the demister unit. This refers to the temperature of the cooling medium at the outlet of the condensing unit. , These are the equilibrium constraint constants; , This is the temperature weighting factor.

[0035] The gas temperature at the outlet of the demisting unit is the temperature of the gas discharged after being processed by the demisting unit, which can be collected by a temperature sensor installed in the outlet pipe of the demisting unit.

[0036] The temperature of the cooling medium at the outlet of the condensing unit is the temperature at which the cooling medium flows out after completing heat exchange in the condensing unit. It can be collected by a temperature sensor installed in the cooling medium outlet pipe of the condensing unit.

[0037] The temperature weighting coefficient is a coefficient used to weight the outlet gas temperature of the demister unit and the outlet cooling medium temperature of the condenser unit. Preferably, it is a coefficient used in the calculation. It equals 0.7. The value is equal to 0.3, because the gas-liquid interface temperature is more affected by the gas outlet temperature, and this ratio can reflect the actual gas-liquid interface heat transfer state.

[0038] The gas-liquid interface equivalent temperature is obtained by weighted calculation of the outlet gas temperature of the demisting unit and the outlet cooling medium temperature of the condensing unit, and can characterize the actual temperature of the heat exchange interface between the exhaust gas and the cooling medium.

[0039] The equilibrium constraint constant is a constant used when constructing the solid-phase generation equilibrium constraint function, preferably... Equals -20.0, Equal to 6000, obtained by regression of phase equilibrium data based on the ammonia-carbon dioxide-water system, which can accurately describe the constraint relationship of temperature on the formation of ammonium bicarbonate solid phase.

[0040] Ammonia partial pressure is the pressure generated by ammonia in the process gas at the outlet of the demister unit, which is equal to the product of the volume fraction of ammonia and the total pressure of the process gas.

[0041] The partial pressure of carbon dioxide is the pressure generated by carbon dioxide in the process gas at the outlet of the demister unit, which is equal to the product of the volume fraction of carbon dioxide and the total pressure of the process gas.

[0042] Water vapor partial pressure is the pressure generated by water vapor in the process gas at the outlet of the demister unit, which is equal to the product of relative humidity and saturated vapor pressure at that temperature.

[0043] The solid-phase formation equilibrium constraint function is constructed based on the equivalent temperature of the gas-liquid interface and is used to characterize the equilibrium constraint effect of temperature on the formation of ammonium salt solid phases.

[0044] The crystallization chemical potential value is a quantitative indicator reflecting the tendency of ammonium salt solid phase formation. It is obtained by multiplying the partial pressure of ammonia, the partial pressure of carbon dioxide, and the partial pressure of water vapor together with the solid phase formation equilibrium constraint function.

[0045] The weighted calculation of the equivalent temperature of the gas-liquid interface includes coupling the outlet gas temperature of the demister unit and the outlet cooling medium temperature of the condenser unit in a specific ratio. Traditional methods often use a single temperature parameter, which cannot accurately reflect the actual heat transfer state of the gas-liquid interface. When the outlet gas temperature of the demister unit is 40 degrees Celsius and the outlet cooling medium temperature of the condenser unit is 30 degrees Celsius, the equivalent temperature of the gas-liquid interface is 37 degrees Celsius, which is consistent with the actual measured interface temperature and can match the heat transfer scenario of treating ammonia-containing tail gas from soda ash.

[0046] The solid-phase formation equilibrium constraint function adopts an exponential form with the natural constant as the base. This is because the effect of temperature on the solid-phase formation of ammonium salts is a non-linear exponential relationship. The constraint on solid-phase formation is strong at low temperatures and weak at high temperatures. This function form can fit this pattern. Compared with linear functions or other power functions, it is more consistent with the phase equilibrium characteristics of the ammonia-carbon dioxide-water system and can accurately quantify the limiting effect of temperature on the formation of ammonium bicarbonate.

[0047] The quantification of the crystallization chemical potential value includes: cross-dimensional coupling of gas phase component concentration and temperature effect. A single gas phase component parameter or temperature parameter cannot fully characterize the ammonium salt formation trend. However, the crystallization chemical potential value, through the ratio of the product of the partial pressures of the three components to the temperature constraint function, can dynamically reflect the changes in the crystallization trend under different operating conditions. When the partial pressures of ammonia and carbon dioxide increase, the crystallization trend is enhanced, and when the temperature increases, the crystallization trend is suppressed, thus achieving accurate prediction of crystallization risk.

[0048] The method for obtaining the partial pressure of ammonia and carbon dioxide is as follows: First, the volume fraction of ammonia and carbon dioxide in the process gas at the outlet of the demisting unit is measured by tunable semiconductor laser absorption spectroscopy (TDLAS) or Fourier transform infrared spectroscopy (FTIR). Then, the partial pressure values ​​are obtained by multiplying them by the total pressure of the process gas collected by the pressure sensor. These two measurement technologies meet the accuracy requirements of industrial online monitoring and have been maturely applied in the monitoring of ammonia-containing tail gas.

[0049] The calculation of water vapor partial pressure is based on the saturated vapor pressure formula proposed by Buck. This formula is applicable to liquid water surfaces above 0 degrees Celsius. The calculation first obtains the saturated vapor pressure corresponding to the outlet gas temperature of the demisting unit using this formula, and then multiplies it by the gas relative humidity collected by the relative humidity sensor to obtain the water vapor partial pressure.

[0050] The temperature weighting coefficient can be adjusted between 0.6 and 0.8. , Subtract 1 The adjustment is based on the heat exchange efficiency of the condensing unit; when the heat exchange efficiency is high... The size can be increased appropriately when the heat exchange efficiency is low. It can be appropriately increased, and after adjustment, it can still accurately reflect the gas-liquid interface temperature.

[0051] The method for calibrating the equilibrium constraint constant is to take at least 300 consecutive sampling points, calculate the rate of change of pressure difference in the demisting unit at each sampling point as the deposition trend surrogate, and then determine the equilibrium constraint constant by fitting a linear relationship between the deposition trend surrogate and the logarithm of the crystallization chemical potential energy using the least squares method. and The specific value.

[0052] Preferably, the aerosol phase transition hysteresis index, which reflects the liquid-solid conversion ratio of aerosol particles under turbulent conditions, is calculated using the following formula:

[0053]

[0054] in, The aerosol phase transition hysteresis index;

[0055] This is the average relative humidity value. The relative humidity turbulence fluctuation intensity is calculated based on the sliding window statistical characteristics of relative humidity data.

[0056] This is the equivalent deliquescence threshold; It is the numerical stability constant;

[0057] The effective residence time of the process gas is defined as follows: In the formula The effective volume upstream of the defogging unit, This refers to the volumetric flow rate of the process gas.

[0058] This is a time characteristic constant.

[0059] The effective volume upstream of the demisting unit is the space volume in the straight section upstream of the demisting unit where the gas can stay. It is preferably a fixed value calculated based on the actual structure of the equipment to ensure that the evolution time of the gas in front of the demisting unit can be accurately reflected. For common equipment, this volume corresponds to a straight section length of 1.5 meters.

[0060] Process gas volumetric flow rate is the volume of process gas flowing through the demister unit per unit time, which can be collected by a vortex flow meter or electromagnetic flow meter installed in the inlet pipe of the demister unit.

[0061] The effective residence time of process gas is the duration of residence of process gas in the effective volume upstream of the demister unit, which is equal to the ratio of the effective volume upstream of the demister unit to the volumetric flow rate of the process gas.

[0062] Relative humidity data is the percentage of water vapor content in process gas compared to the saturated water vapor content at the same temperature. It can be collected by a capacitive relative humidity sensor installed in the upstream pipeline of the demister unit.

[0063] The size of the statistical sliding window is the number of continuous data points or the time span used for statistical analysis of relative humidity data. It is preferably 60 data points corresponding to 10 minutes to balance the timeliness and stability of data statistics and avoid interference from short-term fluctuations.

[0064] The average relative humidity value is the arithmetic mean of the relative humidity data within the statistical sliding window.

[0065] The relative humidity turbulence fluctuation intensity is the degree of fluctuation of relative humidity data from the average value within a statistical sliding window, calculated using the standard deviation.

[0066] The equivalent deliquescence threshold is the critical relative humidity at which the mixed salt spray begins to deliquulate. It is preferably a fixed value calibrated by experiments to match the actual deliquescence characteristics of the mixed salt spray in the ammonia-containing tail gas of soda ash. The common range is between 0.4 and 0.9.

[0067] The numerical stability constant is a small constant used to avoid division by zero or numerical oscillations during the calculation process. It is preferably 10 to the power of negative 6, so as to ensure the stability of numerical calculation without affecting the accuracy of the calculation results.

[0068] The time characteristic constant is a characteristic parameter used to construct the time evolution factor. It is preferably 60 seconds to match the typical residence time range of process gas upstream of the demister unit, and can accurately quantify the influence of residence time on phase transformation.

[0069] The phase transition triggering probability characterizes the likelihood of aerosol particles undergoing a liquid-solid phase transition. It is calculated using the logistic function and ranges from 0 to 1.

[0070] The time evolution factor is a parameter characterizing the effect of process gas residence time on phase transformation, and it is constructed by an exponential function based on the effective residence time of the process gas.

[0071] The aerosol phase transition hysteresis index is a quantitative indicator reflecting the liquid-solid conversion ratio of aerosol particles in a turbulent environment. It is equal to the product of the phase transition trigger probability and the time evolution factor.

[0072] The calculation of the phase transition trigger probability includes dividing the difference between the average relative humidity value and the equivalent deliquescence threshold by the relative humidity turbulence fluctuation intensity and then inputting the result into the logistic function. Traditional methods often directly use a single humidity threshold to determine the phase transition, ignoring the influence of humidity fluctuations in turbulent environments. For example, when the average relative humidity is 0.7, the equivalent deliquescence threshold is 0.6, and the relative humidity turbulence fluctuation intensity is 0.02, the ratio of the difference to the fluctuation intensity is 5. After inputting the result into the logistic function, the phase transition trigger probability is approximately 0.99, which accurately reflects the characteristic of easy phase transition triggering under high humidity fluctuations and is suitable for complex operating conditions in turbulent environments.

[0073] The time evolution factor is constructed using a negative exponential form, where 1 is subtracted from the natural constant. This is because the influence of gas residence time on phase transformation exhibits asymptotic saturation; the longer the residence time, the more complete the phase transformation. This functional form accurately fits this pattern. When the effective residence time of the process gas is 60 seconds and the time characteristic constant is 60 seconds, the time evolution factor is approximately 0.63. This indicates that the contribution of residence time to phase transformation has reached a relatively high level at this point, and further extending the residence time would have limited improvement in contribution, which aligns with the actual phase evolution pattern.

[0074] The synthesis logic of the aerosol phase transition hysteresis index is the first to couple the phase transition triggering condition with the time dimension. A single phase transition triggering probability cannot reflect the impact of residence time on the completion of the phase transition, while the time evolution factor can supplement this dimension. For example, when the phase transition triggering probability is 0.8 and the time evolution factor is 0.63, the aerosol phase transition hysteresis index is 0.504, which reflects both the high probability of phase transition triggering and the partial completion of the phase transition due to residence time, and can comprehensively quantify the liquid-solid conversion ratio of aerosols under turbulent conditions.

[0075] The size of the statistical sliding window can be adjusted between 30 and 120 data points, corresponding to a time span of 5 to 20 minutes. Based on the stability of the process gas flow rate, the window size can be increased when the flow rate fluctuates greatly and decreased when the flow rate is stable, ensuring that the statistical results can reflect the true humidity fluctuation characteristics.

[0076] The calibration method for the equivalent deliquescence threshold is as follows: fix the condensation and washing conditions for 30 minutes, increase the relative humidity by 0.05 every 10 minutes in the range of 0.4 to 0.9 by spray humidification, record the pressure difference change of the demisting unit, calculate the derivative of the pressure difference with respect to the relative humidity, and take the relative humidity corresponding to the maximum value of the derivative as the equivalent deliquescence threshold. This calibration method can eliminate the limitations of the deliquescence threshold of a single salt and is suitable for mixed salt spray scenarios.

[0077] The numerical stability constant can be set between 10 to the power of -8 and 10 to the power of -4, depending on the magnitude of the values ​​during the calculation process. This ensures that the division by zero problem is avoided and that the accuracy of the calculation results is not affected by excessively large values. In practical applications, the value can be adjusted according to the typical values ​​of the relative humidity turbulence fluctuation intensity.

[0078] The adjustment range of the time characteristic constant can be between 30 and 120 seconds. The adjustment is based on the effective volume of the upstream of the demisting unit. When the volume is large, the time characteristic constant can be increased appropriately, and when the volume is small, it can be decreased appropriately to ensure that the influence of residence time on phase transformation can be accurately quantified and matched with the actual structure of the equipment.

[0079] Preferably, the calculation is based on the liquid hold-up load value of the demister calculated from the wet operating pressure difference of the demister unit, and the calculation formula is as follows:

[0080]

[0081] in, This represents the liquid holdup load value for the demister. The differential pressure during wet operation of the demisting unit; For reference wet pressure drop calibration value;

[0082] This is a normalized limiting function used to restrict the calculation results to a closed interval between zero and one.

[0083] The theoretical dry-state pressure drop is calculated using the following formula:

[0084]

[0085] In the formula, It is the dry-state friction factor; Density of the process gas; The apparent flow rate of the process gas;

[0086] The specific surface area of ​​the wire mesh in the demisting unit; The thickness of the wire mesh pad for the defogging unit; The porosity of the wire mesh in the defogging unit.

[0087] The wire mesh structure parameters of the defogging unit are the geometric characteristic parameters of the wire mesh within the defogging unit, including the wire mesh specific surface area, wire mesh pad thickness, and porosity. These parameters can be obtained through technical drawings provided by the equipment manufacturer or by directly measuring the actual wire mesh.

[0088] The hydrodynamic parameters of process gases are parameters that describe the flow characteristics of process gases, including process gas density and apparent flow velocity.

[0089] The dry friction factor is the friction coefficient used to calculate the dry pressure drop of the demister unit. It is preferably 0.35 and is obtained by regression based on the dry flow test data of the wire mesh demister. It can reflect the friction resistance characteristics of the gas during dry flow.

[0090] The theoretical dry pressure drop is the pressure loss caused solely by gas flow and the wire mesh structure when there is no liquid phase retention in the process gas within the demister unit.

[0091] The wet operation differential pressure of the demister unit is the pressure difference between the inlet and outlet of the demister unit under normal liquid-containing operation. It can be collected by differential pressure transmitters installed on the inlet and outlet pipelines of the demister unit.

[0092] The wet pressure drop contribution is the portion of the pressure loss caused solely by liquid phase retention in the wet operating pressure differential of the demisting unit.

[0093] The reference wet pressure drop calibration value is a benchmark value used to normalize the wet pressure drop contribution value. It is preferably 500 Pa, which is the wet pressure drop range commonly used in industrial wire mesh demisters. This can reasonably limit the liquid holdup load value to the range of 0 to 1.

[0094] The normalized limiting function is a function used to restrict the calculation results to a specific range. Here, its function is to limit the liquid hold-up load value of the demister to a closed range of 0 to 1.

[0095] The liquid holdup load value of the demister is a quantitative indicator reflecting the degree of liquid phase retention in the demister unit, and its value ranges from 0 to 1.

[0096] The calculation logic for the theoretical dry-state pressure drop involves coupling the dry-state friction factor, process gas density, the square of the apparent velocity of the process gas, the specific surface area of ​​the wire mesh, the thickness of the wire mesh pad, and the cube of the porosity in a specific form. Traditional methods often use empirical formulas to estimate the dry-state pressure drop, without clearly integrating the geometric resistance characteristics of the wire mesh structure with the square relationship of the fluid dynamic parameters. For example, when the dry-state friction factor is 0.35, the process gas density is 1.2 kg / m³, the apparent velocity of the process gas is 1.67 m / s, the specific surface area of ​​the wire mesh is 100 m² / m³, the thickness of the wire mesh pad is 0.1 m, and the porosity is 0.97, the calculated theoretical dry-state pressure drop is approximately 85 Pa, with a deviation of less than 5% from the actual dry-state experimental measurement value, accurately adapting to the dry-state resistance calculation scenario of wire mesh demisters.

[0097] The quantification logic of the demister liquid holdup value is to extract the wet pressure drop contribution value by subtracting the theoretical dry pressure drop value from the wet operating pressure difference, and then normalizing it. Traditional methods cannot directly quantify the degree of liquid retention and mostly rely on indirect observation and judgment, thus converting the pressure difference signal into an intuitive liquid holdup index. When the wet operating pressure difference of the demister unit is 280 Pa and the theoretical dry pressure drop value is 85 Pa, the wet pressure drop contribution value is 195 Pa. Dividing this by the reference wet pressure drop calibration value of 500 Pa yields a liquid holdup value of 0.39, which accurately reflects the liquid retention level in the demister at this time.

[0098] The calculation of process gas density is based on the ideal gas law, which states that process gas density equals the total pressure of the process gas multiplied by the molar mass, then divided by the gas constant and the absolute temperature. The molar mass can be calculated using the typical components (ammonia, carbon dioxide, water vapor, and air) and their volume fractions of soda ash tail gas. The gas constant is taken as 8.314 joules per mole per Kelvin, and the absolute temperature is the actual temperature of the process gas (units converted to Kelvin).

[0099] There are two ways to obtain the wire mesh structure parameters. One is to consult the technical manual of the demister equipment, where the manufacturer will clearly provide key parameters such as the wire mesh specific surface area, wire mesh pad thickness, and porosity. The other is to measure the actual object if there is no technical manual. The wire mesh specific surface area can be calculated by measuring the diameter and length of a single wire mesh and combining it with the weaving density of the wire mesh. The wire mesh pad thickness is measured with a ruler, and the porosity is calculated by measuring the mass, volume, and material density of the wire mesh.

[0100] The dry friction factor can be adjusted between 0.3 and 0.4. The adjustment depends on the material and weaving method of the wire mesh. The lower limit can be used for metal wire mesh, while the upper limit can be used for plastic wire mesh or densely woven wire mesh. After adjustment, it can still accurately reflect the dry friction resistance characteristics.

[0101] The adjustment range of the reference wet pressure drop calibration value can be between 300 Pa and 800 Pa. The adjustment is based on the processing load of the demisting unit. When the processing load is high, it can be increased appropriately, and when the processing load is low, it can be decreased appropriately to ensure that the liquid holding load value can effectively distinguish the different liquid phase retention degrees.

[0102] Preferably, the multi-parameter correlation control index, which includes the crystallization chemical potential energy value, aerosol phase transition hysteresis index, demister liquid holding capacity value, deposition layer periodic spacing value, and outlet ammonia concentration deviation value, is calculated using the following formula:

[0103] The multi-parameter correlation control index is marked as follows: Its definition is:

[0104]

[0105] in, to These are the weighting coefficients; These are the target settings for each parameter; This refers to the monitored value of ammonia concentration at the export point. The differential pressure during wet operation of the demisting unit;

[0106] The risk index is calculated using the following formula:

[0107]

[0108] In the formula, For exponential parameters; This is a normalized reference value; These are the crystallization chemical potential energy value, aerosol phase transition hysteresis index, relative humidity turbulence fluctuation intensity, and effective residence time of process gas, respectively.

[0109] The periodic spacing value of the deposition layers is calculated using the following formula:

[0110]

[0111] In the formula, The apparent flow rate of the process gas; It is the numerical stability constant;

[0112] The dominant frequency of the turbulent humidity field. The formulas for calculating the timescale of droplet drying are as follows:

[0113]

[0114] In the formula, The intensity of the relative humidity fluctuation rate; The baseline drying time; This is a correction factor.

[0115] The relative humidity fluctuation rate intensity is the degree of fluctuation in the rate of change of relative humidity data over time within a statistical sliding window, calculated through numerical differentiation and standard deviation.

[0116] The correction factor is a parameter used to correct the baseline drying time, preferably 0.3, to match the influence of the crystallization chemical potential on the droplet drying process, and can accurately correlate the chemical trend with the physical drying rate.

[0117] The baseline drying time is the basic drying time of the droplets without considering the influence of the chemical potential energy of crystallization, preferably 20 seconds, based on the natural drying time range of typical droplets in the ammonia-containing tail gas of soda ash.

[0118] The droplet drying timescale is the actual timescale at which the droplet completes drying, taking into account the influence of the crystallization chemical potential energy.

[0119] The dominant frequency of the turbulent humidity field is the main frequency of relative humidity fluctuations under turbulent conditions, reflecting the periodic characteristics of humidity changes.

[0120] The periodic spacing value of the deposition layers is the interlayer distance between the dense crystalline shell layer and the loose pulverized layer that are alternately stacked within the defogging unit.

[0121] The index parameters are used to adjust the weights of various influencing factors when constructing the morphological risk index. The preferred values ​​are a = 1.2, b = 1.5, c = 1.0, and d = 0.5, which are obtained through regression analysis of multiple sets of working condition data and can balance the contribution of each factor to morphological risk.

[0122] The normalized reference value is a benchmark value used to normalize the relative humidity turbulence fluctuation intensity and the effective residence time of process gas. It is preferably σref equal to 0.02 and τref equal to 5 seconds to adapt to the typical numerical range of the two types of parameters and ensure that the normalized result is within a reasonable range.

[0123] The morphological risk index is an indicator that quantifies the risk of abnormal sediment morphology by comprehensively considering crystallization trend, phase hysteresis, turbulence intensity, and residence time.

[0124] The target values ​​for each parameter are the ideal values ​​of the pre-set morphological risk index, liquid holding load, outlet ammonia concentration, demisting unit pressure difference and deposition layer spacing. Preferably, Λ is equal to 1.0, H is equal to 0.35, ΔP is equal to 300 Pa, and Δx is equal to 0.8 m. C* is set according to local environmental protection standards to balance treatment efficiency and equipment operation stability.

[0125] The outlet ammonia concentration monitoring value is the concentration of ammonia in the process gas at the outlet of the demisting unit, which can be collected by tunable semiconductor laser absorption spectroscopy or Fourier transform infrared spectroscopy.

[0126] The weighting coefficients are used to adjust the importance of each deviation item when constructing multi-parameter correlation control indicators. The preferred values ​​are w1 = 2, w2 = 1, w3 = 10, w4 = 1, and w5 = 0.5, so as to highlight the priority of meeting the export ammonia concentration standard, while taking into account the morphological risks and equipment operating status.

[0127] Multi-parameter correlation control index is a quantitative indicator that integrates the deviations of various state parameters from the target value, and is used to guide subsequent multi-variable linkage adjustment.

[0128] The estimation logic for the dominant frequency of the turbulent humidity field couples the intensity of the relative humidity fluctuation rate with the intensity of the relative humidity turbulent fluctuation, calculating it using a specific proportional relationship and pi. Traditional methods do not consider the synergistic effect of the rate and amplitude of humidity changes in turbulent environments, and therefore cannot accurately capture the dominant period of humidity fluctuations. For example, when the intensity of the relative humidity fluctuation rate is 3.0 × 10⁻⁴ per second and the intensity of the relative humidity turbulent fluctuation is 0.018, the calculated dominant frequency is approximately 0.0026 Hz, which is consistent with the fluctuation period of the actual turbulent humidity field and can accurately reflect the rhythm of humidity changes.

[0129] The correction logic for the droplet drying timescale is to correct the baseline drying time using a logarithmic function based on the crystallization chemical potential energy, thus linking the chemical crystallization trend with the physical drying process. When the crystallization chemical potential energy is 50 and the correction coefficient is 0.3, the droplet drying timescale is approximately 20×(1+0.3×ln(51))≈41 seconds, which reflects the actual situation of slower droplet drying under high crystallization trend and avoids the bias of traditional drying time calculation that ignores chemical factors.

[0130] The synthesis logic of the morphological risk index is to couple the crystallization chemical potential energy value, aerosol phase transition hysteresis index, relative humidity turbulence fluctuation intensity, and effective residence time of process gas according to a specific power.

[0131] The construction logic of multi-parameter correlation control indicators is to perform a weighted sum of the squares of the deviations of each parameter from the target value to achieve multi-objective coordinated control.

[0132] The method for calculating the intensity of relative humidity fluctuation rate is to use first-order numerical differentiation, with a control period of 10 seconds as the step size, to calculate the ratio of the relative humidity difference between two adjacent sampling points to the time step size, and then calculate the standard deviation of the difference sequence within the sliding window to obtain the intensity of fluctuation rate.

[0133] The values ​​of the index parameters can be adjusted between a = 1.0 to 1.5, b = 1.2 to 1.8, c = 0.8 to 1.2, and d = 0.3 to 0.7. The adjustment is based on the morphological characteristics of the sediments in the field. If a dense crystalline shell is easily formed, the value of b can be increased; if the turbulent fluctuations have a significant impact, the value of c can be increased.

[0134] The normalized reference values ​​are adjusted within the range of σref between 0.01 and 0.03 and τref between 3 and 8 seconds. The adjustment is based on the humidity stability and flow rate of the process gas. When the humidity fluctuates greatly, σref is increased, and when the flow rate is fast, τref is decreased.

[0135] Methods for determining the target values ​​of each parameter: Λ is set based on the results of sediment microstructure detection; H is determined through experiments to balance collection efficiency and pressure drop; C is implemented in accordance with local environmental emission standards; ΔP is referenced to the rated pressure drop of the demister design; Δx* is set based on the demister structural dimensions and operating experience to ensure that the interlayer spacing does not affect airflow.

[0136] The principle for allocating weighting coefficients is as follows: the highest priority is given to meeting the export ammonia concentration standard, with w3 taking the maximum value; the morphological risk index is related to the sediment structure, with w1 being the next highest; liquid holding capacity, pressure difference, and interlayer spacing are auxiliary indicators, with their weights decreasing in that order, and can be finely adjusted according to the key points of on-site operation.

[0137] Preferably, the multi-variable linkage adjustment strategy based on the multi-parameter correlation control index is calculated using the following formula:

[0138] The flow command value for the next control cycle Calculate using the following formula:

[0139]

[0140] in, The index represents the flow command value for the current control cycle. These correspond to the flow rates of the cooling medium, circulating fluid, and flushing fluid, respectively.

[0141] Output the range limiting function for the actuator; This is the iteration step size coefficient;

[0142] The response gradient value of the multi-parameter correlated control index to each flow variable is approximately calculated using the finite difference method:

[0143]

[0144] In the formula, The multi-parameter correlation control index; This is a preset small perturbation amount.

[0145] Cooling medium flow rate is the fluid flow rate through the condensation unit used to cool process gases, and it is the core variable for adjusting the condensation effect.

[0146] The circulating liquid flow rate of the washing unit is the volumetric flow rate of the washing liquid used in the washing unit to absorb ammonia and carbon dioxide in the exhaust gas.

[0147] The flushing fluid flow rate of the demisting unit is the fluid flow rate used to flush out deposits within the demisting unit, which can reduce deposit accumulation.

[0148] The preset small disturbance is a small change applied to each flow command value to calculate the response gradient value. It is preferably 0.5% so as to accurately capture the changing trend of the control index without affecting the stable operation of the system.

[0149] Multi-parameter correlation control indicators are single quantitative indicators that integrate deviations from multiple dimensions such as morphological risk, liquid holding capacity, and emission concentration, and are used to guide the direction of regulation.

[0150] The iteration step size coefficient is a parameter that controls the correction range of the flow command value. It is preferably 0.8 to balance the adjustment speed and system stability and avoid oscillation caused by over-adjustment.

[0151] The response gradient value is the sensitivity of a multi-parameter correlated control index to various flow variables, reflecting the magnitude of the impact of flow changes on the control index.

[0152] The flow command value for the current control cycle is the flow setting value sent to the actuator during the current control period.

[0153] The flow command value for the next control cycle is the flow setpoint value sent to the actuator in the next time period after response gradient correction.

[0154] The actuator output range limiting function is a function that limits the flow command value to the operable range of the actuator to prevent it from exceeding the equipment's capabilities.

[0155] The preset time series is a sequential arrangement of applying small perturbations to the three flow variables in turn. Preferably, the perturbations are applied to the cooling medium flow rate, circulating fluid flow rate, and flushing fluid flow rate every 10 seconds to avoid mutual interference between the perturbations of multiple variables at the same time.

[0156] The timing design of a multivariate perturbation strategy involves applying perturbations to the three flow variables sequentially at fixed time intervals, rather than simultaneously or randomly. Traditional multivariate regulation often ignores the mutual interference of perturbations, leading to inaccurate gradient calculations. For example, a preset time series could be used to perturb the cooling medium flow rate at second 10, the circulating fluid flow rate at second 20, and the flushing fluid flow rate at second 30, repeating this cycle to ensure that the effect of each perturbation is independently measurable. If the current commanded value of the cooling medium flow rate is 50 cubic meters per hour, applying a 0.5% perturbation will reduce it to 50.25 cubic meters per hour, thus capturing the individual impact of this flow rate change on the control index.

[0157] The finite difference method for calculating the response gradient approximates the gradient by using the ratio of the difference between the control index before and after the perturbation to the perturbation amount, thus adapting to the real-time control requirements of industrial scenarios. For example, if the control index before the perturbation is 1400 and after the perturbation is 1420, and the small perturbation amount is 0.5%, then the response gradient value is (1420-1400) / 0.5%=4000, which can intuitively reflect the sensitivity of the flow variable to the adjustment of the control index.

[0158] The multivariate linkage update law combines gradient descent with a saturation limiting function to achieve continuous regulation. Traditional regulation often uses piecewise rules, which are prone to regulation jumps. For example, if the current circulating fluid flow command is 30 cubic meters per hour, the response gradient is 2000, the iteration step size coefficient is 0.8, and the correction amount is 0.8 × 2000 = 1600 (after dimensionless conversion), if the corrected command value is 32 cubic meters per hour, which does not exceed the execution range of 0-100 cubic meters per hour, it is directly output; if it exceeds the range, it is limited to the boundary value to ensure smooth and stable regulation.

[0159] The preset value range for the small disturbance is between 0.3% and 0.8%, which can prevent the disturbance from being too large at small flow rates and ensure that the disturbance is measurable at large flow rates.

[0160] The iteration step size coefficient can be adjusted between 0.6 and 1.0, depending on the dynamic response characteristics of the system. For systems with a faster response, the coefficient can be increased appropriately, while for systems with a slower response, the coefficient can be decreased appropriately, ensuring that the adjustment is neither lagging nor oscillating.

[0161] The specific interval of the preset time series can be between 5 and 15 seconds. When the control cycle is 10 seconds, a 10-second interval is used to ensure that a set of perturbation measurements is completed within one control cycle without affecting the normal adjustment rhythm.

[0162] The permissible output range of the actuator is 0 to 100%, corresponding to the valve opening of the regulating valve or the frequency output of the variable frequency pump. This range is the standard range for industrial fluid control actuators.

[0163] like Figure 2 As shown, Figure 2 The schematic diagram of the ammonia-containing tail gas recovery and resource utilization system for soda ash production illustrates the process flow and control logic: After entering through the inlet, the ammonia-containing tail gas flows sequentially through the condensation unit, the washing unit, and the demisting unit, and is finally discharged from the purified tail gas outlet. The system is equipped with a multiphase flow state monitoring module to collect real-time data on temperature, pressure, relative humidity, and outlet ammonia concentration at each key node, and transmits this data to the linkage controller. Based on the monitoring data, the linkage controller dynamically adjusts the cooling medium flow rate in the cooling medium loop and the circulating liquid flow rate in the washing unit. The recovered liquid generated by the condensation unit and the washing unit is collected in the recovered liquid storage tank, realizing the coordinated operation of tail gas purification and ammonia resource recovery.

[0164] Example 2: A system for recovering and recycling ammonia-containing tail gas in soda ash production, comprising the steps of any one of the methods for recovering and recycling ammonia-containing tail gas in soda ash production, including:

[0165] The exhaust gas treatment host includes a condensation unit, a washing unit and a demisting unit connected sequentially by pipelines along the flow direction of the process gas. The condensation unit, washing unit and demisting unit are respectively equipped with a cooling medium flow regulating mechanism, a circulating liquid flow regulating mechanism and a flushing liquid flow regulating mechanism.

[0166] A multiphase flow state monitoring network is deployed at the condensation unit and the demisting unit to collect process gas temperature, pressure and relative humidity data in real time.

[0167] The intelligent control center is communicatively connected to the multiphase flow state monitoring network and the exhaust gas treatment host. The intelligent control center includes a processor and a memory. The memory stores a computer program, and the processor executes the computer program to perform the following operations:

[0168] The state calculation logic is invoked to calculate the crystallization chemical potential energy value reflecting the trend of ammonium salt solid phase formation, the aerosol phase transformation hysteresis index reflecting the liquid-solid conversion ratio of aerosol particles in turbulent environment, and the demister liquid holding load value calculated based on the wet operation pressure difference of the demister unit.

[0169] The indicator construction logic is invoked to establish a multi-parameter correlation control index that includes the crystallization chemical potential energy value, aerosol phase transformation hysteresis index, demister liquid holding load value, deposition layer periodic spacing value and outlet ammonia concentration deviation value.

[0170] The linkage adjustment logic is invoked to generate a multivariable linkage adjustment command based on the multi-parameter correlation control index, and sent to the cooling medium flow rate adjustment mechanism, the circulating fluid flow rate adjustment mechanism, and the flushing fluid flow rate adjustment mechanism to dynamically balance and adjust the cooling medium flow rate, the circulating fluid flow rate, and the flushing fluid flow rate, thereby controlling the microstructure of the deposits inside the demisting unit and maintaining the periodic spacing value of the deposit layer within a preset range.

[0171] Example 3: A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for recovering and recycling ammonia-containing tail gas in soda ash production as described in any one of the examples.

[0172] It should be noted that the interval and threshold sizes are set for ease of comparison. The size of the threshold depends on the amount of sample data and the base number set by those skilled in the art for each set of sample data, as long as it does not affect the proportional relationship between the parameter and the quantized value. Furthermore, the above formulas are all dimensionless calculations, and the formulas are derived from software simulations using a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0173] The embodiments of this example have been described above. However, this example is not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms based on the guidance of this example, and all of them are within the protection scope of this example.

Claims

1. A method for recovering and utilizing ammonia-containing tail gas in soda ash production, applied to a tail gas treatment system comprising a condensation unit, a washing unit, and a demisting unit connected in sequence, characterized in that, include: A multiphase flow state monitoring module is configured to collect process gas temperature, pressure and relative humidity data at the condensation unit and the demisting unit, and to calculate the crystallization chemical potential energy value reflecting the trend of ammonium salt solid phase formation, the aerosol phase transformation hysteresis index reflecting the liquid-solid conversion ratio of aerosol particles in turbulent environment, and the demister liquid holding load value calculated based on the wet operation pressure difference of the demisting unit. Establish a multi-parameter correlation control index that includes the crystallization chemical potential energy value, aerosol phase transformation hysteresis index, demister liquid holding load value, deposition layer periodic spacing value and outlet ammonia concentration deviation value. Based on the multi-parameter correlation control index, a multi-variable linkage adjustment strategy is executed to dynamically balance and adjust the cooling medium flow rate of the condensation unit, the circulating liquid flow rate of the washing unit, and the flushing liquid flow rate of the demisting unit, so as to control the microstructure of the deposits inside the demisting unit and maintain the periodic spacing value of the deposit layer within a preset range.

2. The method for recovering and utilizing ammonia-containing tail gas in soda ash production according to claim 1, characterized in that, The chemical potential energy values ​​for crystallization include: The gas temperature at the outlet of the demisting unit and the cooling medium temperature at the outlet of the condensing unit are monitored in real time, and the equivalent temperature of the gas-liquid interface is obtained by weighted calculation. A solid-phase formation equilibrium constraint function with respect to the equivalent temperature of the gas-liquid interface is constructed using an exponential function with the natural constant as the base. The product of the partial pressures of ammonia, carbon dioxide, and water vapor at the outlet of the demister unit is obtained, and the product is divided by the solid-phase formation equilibrium constraint function to obtain the crystallization chemical potential energy value.

3. The method for recovering and utilizing ammonia-containing tail gas in soda ash production according to claim 2, characterized in that, Aerosol phase transition hysteresis index includes: The effective residence time of the process gas is determined by the ratio of the effective volume upstream of the demister unit to the process gas volume flow rate at the demister unit. The collected relative humidity data were statistically analyzed using a sliding window, and the average relative humidity value and the intensity of relative humidity turbulence fluctuations were calculated respectively. The difference between the average relative humidity value and the preset equivalent deliquescence threshold is calculated, and the ratio of this difference to the relative humidity turbulence fluctuation intensity is input into the logistic function to obtain the phase transition trigger probability. A time evolution factor based on the effective residence time of the process gas is constructed using an exponential function with the natural constant as the base. The product of the phase transition trigger probability and the time evolution factor is used as the aerosol phase transition hysteresis index.

4. The method for recovering and utilizing ammonia-containing tail gas in soda ash production according to claim 3, characterized in that, The liquid hold-up load of the demister includes: Obtain the wire mesh structure parameters of the demisting unit and the hydrodynamic parameters of the process gas. Based on the square relationship of the hydrodynamic parameters of the process gas and the geometric resistance characteristics of the wire mesh structure parameters, calculate the theoretical dry pressure drop of the demisting unit. Subtract the theoretical dry pressure drop value from the real-time collected wet operating pressure difference of the demisting unit to obtain the wet pressure drop contribution value caused only by liquid phase retention; The wet pressure drop contribution value is divided by a preset reference wet pressure drop calibration value, and the resulting quotient is restricted within a normalized range to serve as the liquid holding load value of the demister.

5. The method for recovering and utilizing ammonia-containing tail gas in soda ash production according to claim 4, characterized in that, Establish a multi-parameter correlation control index that includes the crystallization chemical potential energy value, aerosol phase transformation hysteresis index, demister liquid holding capacity value, deposition layer periodic spacing value, and outlet ammonia concentration deviation value, including: The dominant frequency of the turbulent humidity field is estimated based on the ratio of the intensity of the relative humidity fluctuation rate to the intensity of the relative humidity turbulence fluctuation. The baseline drying time is corrected using a logarithmic function based on the crystallization chemical potential value to obtain the droplet drying timescale; The periodic spacing value of the deposition layer is obtained by multiplying the sum of the droplet drying timescale and the reciprocal of the dominant frequency of the turbulent humidity field by the apparent flow rate of the process gas. The crystallization chemical potential energy value, aerosol phase transition hysteresis index, relative humidity turbulence fluctuation intensity and process gas effective residence time are combined into a morphological risk index through power weighted product calculation. Calculate the deviations between the morphological risk index, the liquid holding load value of the demister, the periodic spacing value of the deposition layer, the monitored value of the outlet ammonia concentration, and the wet operating pressure difference of the demister unit and their respective preset target values; perform a weighted summation on the squares of each deviation, and use the resulting weighted sum as the multi-parameter correlation control index.

6. The method for recovering and utilizing ammonia-containing tail gas in soda ash production according to claim 5, characterized in that, Based on the aforementioned multi-parameter correlation control index, a multi-variable linkage adjustment strategy is executed to dynamically balance and adjust the cooling medium flow rate of the condensation unit, the circulating liquid flow rate of the washing unit, and the flushing liquid flow rate of the demisting unit. This aims to control the microstructure of the deposits inside the demisting unit and maintain the periodic spacing of the deposition layer within a preset range, including: According to a preset time sequence, a fixed small disturbance is applied to the current command values ​​of the cooling medium flow rate, circulating fluid flow rate, and flushing fluid flow rate in sequence; Monitor the numerical changes of the multi-parameter associated control index before and after applying the small disturbance, and calculate the ratio of the numerical change to the small disturbance to obtain the response gradient value of each flow variable to the control index. The current command value is corrected by multiplying the preset step size coefficient with the response gradient value, and the flow command value for the next control cycle is calculated. The normalized limiting function is used to limit the flow command value of the next control cycle to the allowable output range of the actuator and output to the corresponding regulating valve or variable frequency pump.

7. A system for recovering and recycling ammonia-containing tail gas in soda ash production, comprising the steps of a method for recovering and recycling ammonia-containing tail gas in soda ash production as described in any one of claims 1-6, characterized in that, include: The exhaust gas treatment host includes a condensation unit, a washing unit and a demisting unit connected sequentially by pipelines along the flow direction of the process gas. The condensation unit, washing unit and demisting unit are respectively equipped with a cooling medium flow regulating mechanism, a circulating liquid flow regulating mechanism and a flushing liquid flow regulating mechanism. A multiphase flow state monitoring network is deployed at the condensation unit and the demisting unit to collect process gas temperature, pressure and relative humidity data in real time. The intelligent control center is communicatively connected to the multiphase flow state monitoring network and the exhaust gas treatment host. The intelligent control center includes a processor and a memory. The memory stores a computer program, and the processor executes the computer program to perform the following operations: The state calculation logic is invoked to calculate the crystallization chemical potential energy value reflecting the trend of ammonium salt solid phase formation, the aerosol phase transformation hysteresis index reflecting the liquid-solid conversion ratio of aerosol particles in turbulent environment, and the demister liquid holding load value calculated based on the wet operation pressure difference of the demister unit. The indicator construction logic is invoked to establish a multi-parameter correlation control index that includes the crystallization chemical potential energy value, aerosol phase transformation hysteresis index, demister liquid holding load value, deposition layer periodic spacing value and outlet ammonia concentration deviation value. The linkage adjustment logic is invoked to generate a multivariable linkage adjustment command based on the multi-parameter correlation control index, and sent to the cooling medium flow rate adjustment mechanism, the circulating fluid flow rate adjustment mechanism, and the flushing fluid flow rate adjustment mechanism to dynamically balance and adjust the cooling medium flow rate, the circulating fluid flow rate, and the flushing fluid flow rate, thereby controlling the microstructure of the deposits inside the demisting unit and maintaining the periodic spacing value of the deposit layer within a preset range.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of a method for recovering and recycling ammonia-containing tail gas in soda ash production as described in any one of claims 1 to 6.

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