Treatment process for natural gas combustion waste gas generated by zinc chloride production based on zinc ash and zinc slag and acid mist waste gas generated by regenerated acid decoction

Abstract

The invention belongs to the technical field of environment-friendly treatment, and provides a treatment process for natural gas combustion waste gas generated by zinc chloride production based on zinc ash and zinc slag and acid mist waste gas generated by regenerated acid decoction, which comprises the following steps: S1, introducing the natural gas combustion waste gas and the acid mist waste gas into a spray tower, carrying out dynamic alkali neutralization treatment and cooling treatment on the basis of an intelligent pH value regulation and control method to obtain primary purified gas; s2, the primary purified gas enters primary plasma dedusting and demisting equipment through a pipeline to be treated, and secondary purified gas is obtained; and S3, the secondary purified gas enters secondary plasma dedusting and demisting equipment to be treated, and final treated tail gas is obtained. According to the invention, the chemical neutralization based on the spray tower and the two-stage plasma deep cracking are combined, the treated waste gas meets the emission limit value in the secondary standard in the Integrated Emission Standard of Air Pollutants, the treatment efficiency is high, the medicament consumption is low, the energy consumption is low, and the problems in the prior art are effectively solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental protection treatment, and specifically relates to a treatment process for waste gas from natural gas combustion in the production of zinc chloride from zinc ash and zinc slag and acid mist waste gas generated by boiling regenerated acid. Background Art

[0002] Zinc ash and zinc slag produced by industrial galvanizing can be used to produce anhydrous zinc chloride, turning waste into treasure. The production process is as follows: raw material pretreatment and acid leaching reaction are first performed. The acid leaching reaction involves reacting industrial hydrochloric acid with a concentration of approximately 31% with zinc slag to produce a zinc chloride solution. After the solution is purified and impurities removed, zinc powder is added to replace heavy metals such as Cu, Pb, and Cd. The purified zinc chloride solution is evaporated and concentrated, then subjected to multi-stage cooling and crystallization, and finally dehydrated in a graphite slope dryer to obtain anhydrous zinc chloride solid. The above production process generates production waste gas, which mainly includes natural gas combustion waste gas, specifically excessive dust particulate matter in natural gas incineration flue gas, and acid mist generated by regenerated acid boiling, specifically the formation of aerosols containing zinc chloride and ammonium chloride with a white smoke trail. For this waste gas, the existing technology has not yet developed a high-efficiency, effective, and economical treatment solution. Summary of the Invention

[0003] The purpose of the present invention is to provide a treatment process for natural gas combustion waste gas and acid mist waste gas generated by regenerated acid boiling in the production of zinc chloride based on zinc ash and zinc slag, so as to solve the technical problems existing in the prior art.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A treatment process for waste gas from natural gas combustion in the production of zinc chloride from zinc ash and zinc slag and acid mist waste gas generated by boiling regenerated acid, comprising the following steps: Step S1: natural gas incineration waste gas and acid mist waste gas are introduced into a spray tower, and subjected to dynamic alkali neutralization treatment and cooling treatment based on an intelligent pH value control method to obtain primary purified gas; wherein the spray tower adopts a double-layer cyclone spray, with a 10% NaOH solution in the upper layer and a 15% Na2CO3 solution in the lower layer; Step S2: The primary purified gas passes through a pipeline and enters a first-stage plasma dust removal and demisting device for processing to obtain a secondary purified gas; wherein the first-stage plasma dust removal and demisting device dynamically adjusts operating parameters based on VOCs online monitoring; Step S3: The secondary purified gas enters the secondary plasma dust removal and mist removal equipment for treatment to obtain the final treated tail gas, which meets the following standards: the emission limit values in the secondary standard of the "Integrated Emission Standard of Air Pollutants" (GB16297-1996).

[0005] In one embodiment, the dynamic alkali neutralization treatment based on the pH value intelligent control method in step S1 is specifically implemented as follows: Step S1.1: introducing the acid mist waste gas and the natural gas incineration waste gas into a spray tower, and performing a gas-liquid contact reaction by spraying an alkaline solution in layers; Step S1.2: Real-time monitoring of pH values at different heights within the spray tower, wherein the upper region is maintained at pH 10.3-10.7, the middle region is maintained at pH 8.7-9.3, and the lower region is maintained at pH 7.0-8.0; Step S1.3: Based on the monitoring data of step S1.2, the dosage of NaOH and Na2CO3 solution is dynamically regulated by PID control; In step S1.3, when the pH value of the lower layer is detected to be less than 6.5 and lasts for more than time t, dosing is performed simultaneously: NaOH solution and Na2CO3 solution are added, and the dosing rate is increased to 150-200% of the baseline value.

[0006] In one embodiment, in step S1.2, three sets of online pH sensors are used to monitor the pH values of the upper, middle, and lower reaction zones, respectively. When the pH value difference between any two layers is greater than 0.5, the flow ratio of the upper layer spraying alkaline solution and the lower layer spraying alkaline solution (based on the spray pump) is adjusted to be within the range of (1.5-2.5):1.

[0007] In one embodiment, the PID control parameters in step S1.3 satisfy: (1) Proportional coefficient K p =2.2-2.8, integration time T i =15-25s, differential time T d =3-5s; (2) When the exhaust gas flow rate change rate is detected to be greater than 5% / min, adjust K p to 3.0-3.5, T i Shortened to 8-12s.

[0008] In one embodiment, the specific implementation of the first-level plasma dust removal and mist removal equipment in step S2 dynamically adjusting the working parameters based on VOCs online monitoring is as follows: Step S2.1: Based on the sensor array, real-time data on the pollutant concentration and composition of the primary purified gas is obtained; Step S2.2: Calculating the comprehensive pollution index I and the actual concentration C based on a data fusion algorithm that integrates photoionization detection values, infrared characteristic spectrum intensity, and differential sensor data; Step S2.3: Dynamically adjust the plasma field intensity parameters of the first-stage plasma dust and mist removal equipment based on the actual concentration C: when the actual concentration C is less than 50 mg / m³, the plasma operates at the baseline; when the actual concentration C is greater than or equal to 50 mg / m³, adjust the plasma electric field intensity U according to U=8+0.02×(C-50) kV / cm.

[0009] In one embodiment, in step S2.1, the sensor array includes: a photoionization detector; a Fourier transform infrared spectrometer; and three groups of differential gas sensors arranged axially along the pipeline.

[0010] In one embodiment, in step S2.2, the calculation of the comprehensive pollution index I and the actual concentration C based on the data fusion algorithm is specifically implemented as follows: Step S2.2.1: Assigning reference weights to the photoionization detection value, infrared characteristic spectrum intensity and differential sensor data: Photoionization detection value PID: Weight = 0.6w; infrared characteristic peak intensity FTIR: weight = 0.3; Differential sensor data ΔS: weight = 0.1; Step S2.2.2: Dynamic weight adjustment strategy: When the ambient humidity is greater than 70%RH, the PID weight Reduced to 0.5, FTIR weight Increase to 0.4, or, when the gas velocity is greater than 3m / s, the ΔS weight Increase to 0.2, and reduce the remaining weights in proportion; obtain the final weight distribution based on the dynamic weight adjustment strategy; Step S2.2.3: Based on the final weight distribution, calculate the comprehensive pollution index I according to the following formula: = ,in, is the absorbance of characteristic peak k, is the response factor of pollutant k; Step S2.2.4: Calculate the actual concentration: According to the formula = ,in, The upper limit of the range of the photoionization detector.

[0011] In one embodiment, the method further includes step S2.4: when the rate of change of the actual concentration C is greater than 10% / min, adjusting and extending the exhaust gas residence time in advance.

[0012] In one embodiment, in step S3, the secondary purified gas is passed through an air duct into a secondary plasma dust removal and mist removal device, and ozone is added through an ozone generator in the air duct along the flow direction of the secondary purified gas, and the ozone concentration decreases from 150 ppm to 50 ppm.

[0013] In one embodiment, during the ozone process, the ozone dosage is calculated according to the following formula:

[0014] Where k is a coefficient, ranging from 1.2 to 1.5. To detect the pollutant concentration of the secondary purified gas in real time, is the flow rate of secondary purge gas.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) According to the process provided by the present invention for treating waste gas from natural gas combustion in the production of zinc chloride from zinc ash and zinc slag and acid mist waste gas generated by boiling regenerated acid, chemical neutralization based on a spray tower and two-stage plasma deep cracking are combined. The treated waste gas meets the emission limit values of the secondary standard in the "Integrated Emission Standard of Air Pollutants" (GB16297-1996). Not only is the treatment efficiency high, but the process also requires less reagent consumption and the plasma module has low energy consumption, effectively solving the problems existing in the prior art.

[0016] (2) According to the present invention, double-layer swirl spraying is adopted for spraying. The upper layer adopts 10% NaOH solution to capture acidic components, and the lower layer is configured with 15% Na2CO3 solution to enhance heavy metal precipitation. At the same time, combined with the dynamic regulation of the dosage of NaOH and Na2CO3 solution, not only the neutralization efficiency is effectively improved, but also the consumption of alkaline solution and the amount of waste liquid generated are reduced while ensuring the neutralization reaction, thereby reducing costs.

[0017] (3) According to the present invention, a sensor array is installed at the air inlet end of the first-stage plasma dust removal and mist removal equipment, and the pollution index I and the actual concentration C are comprehensively calculated based on a dynamic weight strategy. Finally, the plasma field intensity parameters of the first-stage plasma dust removal and mist removal equipment are dynamically adjusted according to the actual concentration. Not only is the detection error low, but also the dynamic power regulation of the plasma reduces energy consumption by 30-40% compared with conventional fixed power operation.

[0018] (4) According to the present invention, ozone is added to the secondary purified gas before it enters the secondary plasma dust removal and mist removal equipment to construct an ozone synergistic zone to decompose organic aerosols. While ensuring efficient oxidation, the operating cost is significantly reduced. The design of ozone gradient concentration addition effectively suppresses the generation of by-products, ensuring the effect of subsequent waste gas treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of a process of an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to have a clearer understanding and knowledge of the present invention, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described below are only used to explain the present invention and facilitate understanding. The technical solutions provided by the present invention are not limited to the technical solutions provided by the following embodiments, and the technical solutions provided by the embodiments should not limit the scope of protection of the present invention.

[0021] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. Therefore, the drawings only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the shape, quantity and proportion of each component can be changed at will, and the component layout may also be more complicated.

[0022] Example like Figure 1 As shown, this embodiment provides a process for treating the waste gas from natural gas combustion in the production of zinc chloride based on zinc ash and zinc slag and the acid mist waste gas generated by boiling regenerated acid. It is mainly used to treat the waste gas generated by the production of anhydrous zinc chloride from zinc ash and zinc slag generated by industrial galvanizing, including: natural gas combustion waste gas and part of the acid mist generated by boiling regenerated acid.

[0023] The process provided in this embodiment for treating the waste gas from natural gas combustion and acid mist generated by boiling regenerated acid in the production of zinc chloride based on zinc ash and zinc slag specifically comprises the following steps: 1. Step S1: Dynamically neutralize and cool the exhaust gas through a spray tower.

[0024] The natural gas incineration waste gas and acid mist waste gas are introduced into the spray tower, and dynamic alkali neutralization treatment and cooling treatment are carried out based on the intelligent pH value control method to obtain primary purified gas; among them, the spray tower adopts double-layer swirl spray, the upper layer uses 10% NaOH solution (flow rate 3-5m³ / h) to capture acidic components, and the lower layer is configured with 15% Na2CO3 solution (flow rate 2-3m³ / h) to enhance heavy metal precipitation.

[0025] In this step, the specific implementation of dynamic alkali neutralization treatment based on the pH value intelligent control method is as follows: Step S1.1: The acid mist waste gas and the natural gas incineration waste gas are introduced into a spray tower, and an alkaline solution is sprayed in layers to cause a gas-liquid contact reaction. Specifically, the spraying is achieved by a spray pump, with a 10% NaOH solution in the upper layer at a spray density of 3-5 m³ / (m²·h), and a 15% Na2CO3 solution in the lower layer at a spray density of 2-3 m³ / (m²·h). The spray liquid contacts the waste gas in countercurrent, and the gas-liquid ratio is controlled at (1000-1500):1. Step S1.2: Real-time monitoring of pH values at different heights within the spray tower, with the upper zone maintaining a pH of 10.3-10.7, the middle zone maintaining a pH of 8.7-9.3, and the lower zone maintaining a pH of 7.0-8.0. Three sets of online pH sensors are used to monitor the pH values of the upper, middle, and lower reaction zones, respectively, with a sampling frequency of ≥1 time / second. When the pH difference between any two zones is greater than 0.5, a spray flow redistribution mode is triggered, and the flow ratio of the upper-layer spray alkaline solution to the lower-layer spray alkaline solution (based on the spray pump) is adjusted to within a range of (1.5-2.5):1. Step S1.3: Based on the monitoring data of step S1.2, the dosage of NaOH and Na2CO3 solution is dynamically controlled by PID control; the PID control parameters meet the following requirements: (1) Proportional coefficient K p =2.2-2.8, integration time T i =15-25s, differential time T d =3-5s; (2) When the exhaust gas flow rate change rate is detected to be greater than 5% / min, adjust K p to 3.0-3.5, T i Shortened to 8-12s; In step S1.3, when the pH value of the lower area is detected to be less than 6.5 and lasts for more than time t (defined by technicians, for example, 10 seconds), dosing is performed simultaneously: NaOH solution and Na2CO3 solution are added, and the dosing rate is increased to 150-200% of the baseline value (the baseline value is the initial setting value).

[0026] The hardware system configured for the intelligent control method includes: pH sensor array: using a composite online pH monitoring probe (measuring range 0-14, resolution ±0.01), three groups of sensors are set up in the spray tower at the upper, middle and lower levels to monitor the pH distribution of liquid film layers at different heights in real time; PLC controller: built-in fuzzy PID algorithm module, integrated feedforward-feedback composite control model, response time ≤0.5s, and can receive synchronous signal input from the exhaust gas flow meter and temperature sensor (PT100 type); automatic dosing system: including NaOH storage tank, Na2CO3 storage tank, metering pump (accuracy ±1%FS) and pneumatic ball valve (opening adjustment accuracy 0.1%), and linked to the PLC through the Modbus protocol.

[0027] Through this step, dynamic regulation can control pH fluctuations within the range of ±0.2. Compared with traditional manual regulation, it effectively improves the neutralization efficiency and makes the spraying of alkaline solution more precise. While ensuring the neutralization reaction, it reduces the consumption of alkaline solution and the amount of waste liquid generated, thereby reducing costs.

[0028] 2. Step S2: The primary purified gas passes through a pipeline and enters a first-level plasma dust removal and mist removal equipment for treatment to obtain a secondary purified gas.

[0029] The first-level plasma dust removal and mist removal equipment applies a field strength of 8kV / cm, an initial residence time of 0.8-1.2s, a discharge form of pulse corona, and an energy density of 12J / L. It is mainly used for the charged removal of heavy metal particles.

[0030] In this step, the first-stage plasma dust and mist removal equipment dynamically adjusts its operating parameters based on VOCs online monitoring. The specific implementation is as follows: Step S2.1: Install a VOCs detection sensor at the air inlet of the primary plasma dust removal and mist removal equipment. Based on the sensor array, the pollutant concentration and composition data of the primary purified gas are obtained in real time. The sensor array includes: a photoionization detector (PID, detection range 0-2000ppm, resolution 0.1ppm), which is used to monitor the total VOCs concentration in real time; a Fourier transform infrared spectrometer (FTIR, spectral range 600-4000cm -1 ), which is used to identify characteristic pollutants; three sets of differential gas sensors are set axially along the pipeline to eliminate concentration gradient errors. This setup achieves multi-source data fusion and reduces detection errors; preferably, daily zero-point calibration is performed by introducing high-purity nitrogen (purity ≥ 99.999%) to calibrate the sensor baseline; Step S2.2: Calculate the comprehensive pollution index I and actual concentration C based on a data fusion algorithm. The data fusion algorithm integrates the photoionization detection value, infrared characteristic spectrum intensity, and differential sensor data. The specific implementation of calculating the comprehensive pollution index I and actual concentration C based on the data fusion algorithm is as follows: First, the sensor data was preprocessed. This included dimensionless conversion of the photoionization detection (PID), infrared characteristic peak intensity (FTIR), and differential sensor data (ΔS). The PID range was 0–2000 ppm, the FTIR absorbance was 0–2.5 AU, and the ΔS range was -10% to +10%. Lagrange interpolation was used to synchronize the data based on sensor response time differences (PID: 1 s, FTIR: 5 s, ΔS: 0.5 s). The following steps were then performed: Step S2.2.1: Assigning reference weights to the photoionization detection value, infrared characteristic spectrum intensity, and differential sensor data: Photoionization detection value PID: Weight = 0.6w; infrared characteristic peak intensity FTIR: weight = 0.3; Differential sensor data ΔS: weight = 0.1; Step S2.2.2: Dynamic weight adjustment strategy: When the ambient humidity is greater than 70%RH, the PID weight Reduced to 0.5, FTIR weight Increase to 0.4, or, when the gas velocity is greater than 3m / s, the ΔS weight Increase to 0.2, and reduce the remaining weights proportionally; the final weight distribution is obtained based on the dynamic weight adjustment strategy; Step S2.2.3: Based on the final weight distribution, calculate the comprehensive pollution index I according to the following formula: = ,in, is the absorbance of characteristic peak k, is the response factor of pollutant k (e.g., benzene α = 1.2, toluene α = 1.0), Indicates the contribution value of infrared characteristic peak intensity; Based on the above steps, a dynamic weight adjustment strategy is adopted to reduce humidity interference; Step S2.2.4: Calculate the actual concentration: According to the formula = ,in, The upper limit of the range of the photoionization detector.

[0031] Calculation example: Scenario: The detection data at a certain moment is as follows PID value: 850 ppm (normalized value 0.425); FTIR characteristic peaks: benzene (1018 cm⁻¹, A=1.2, α=1.2), toluene (729 cm⁻¹, A=0.8, α=1.0); ΔS: +6% (normalized value 0.6); Environmental parameters: temperature 25°C, humidity 65% RH, flow rate 2.5 m / s; Calculation process: FTIR contribution value = 1.2 × 1.2 (benzene) + 0.8 × 1.0 (toluene) = 1.44 + 0.8 = 2.24 → normalized value 2.24 / 2.5 = 0.896; comprehensive pollution index: I = 0.6 × 0.425 + 0.3 × 0.896 + 0.1 × 0.6 = 0.255 + 0.269 + 0.06 = 0.584; Converted to actual concentration: C = 2000ppm × 0.584 = 1168ppm.

[0032] Step S2.3: Dynamically adjust the plasma field intensity parameters of the first-stage plasma dust and mist removal equipment based on the actual concentration C: when the actual concentration C is less than 50 mg / m³, the plasma baseline operation (electric field intensity 8 kV / cm) is performed; when the actual concentration C is greater than or equal to 50 mg / m³, the plasma electric field intensity U is adjusted according to U=8+0.02×(C-50) kV / cm, and the plasma power frequency is adjusted to 10-15 kHz.

[0033] In addition, step S2.4 is also included: when the change rate of the actual concentration C is greater than 10% / min, the exhaust gas residence time is adjusted in advance and extended; for example: adjusted from 08-1.2s to 1.5-2.0s. This step is used for feedforward compensation to avoid the impact of excessive changes in the actual concentration C on the treatment effect.

[0034] 3. The secondary purified gas enters the secondary plasma dust removal and mist removal equipment for treatment to obtain the final treated exhaust gas.

[0035] The secondary plasma dust removal and mist removal equipment applies a field strength of 9-12 kV / cm to enhance the deep cracking of small molecular pollutants. The field strength can be adjusted according to the detection situation. For example, when benzene series (characteristic peak 1018 cm -1 When the field is increased to 11-12 kV / cm (with TiO2 catalytic layer, temperature ≥ 300 °C), when chlorine-containing organic matter (such as chlorobenzene, characteristic peak 740 cm -1 ), the field strength drops to 9-10 kV / cm.

[0036] The secondary purified gas is passed through an air duct into a secondary plasma dust removal and mist removal device. Ozone is added in the air duct along the flow direction of the secondary purified gas (from the air inlet to the air outlet) through an ozone generator (three-level gradient, equipped with three ozone generators), and the ozone concentration decreases from 150 ppm to 50 ppm (150 ppm / 100 ppm / 50 ppm). Preferably, the ozone addition method is: the generated ozone is mixed with compressed air (mixing ratio 1:5~1:10) and sprayed into the air duct in a swirling manner. During the ozone process, the ozone dosage is calculated according to the following formula:

[0037] Where k is a coefficient, ranging from 1.2 to 1.5 (selected by technicians based on actual conditions) The pollutant concentration of the secondary purified gas is detected in real time (a photoionization detector is set at the inlet to detect the pollutant concentration (PID) of the secondary purified gas based on the photoionization detector. The instrument specifications are the same as those mentioned above). is the flow rate of secondary purge gas (based on gas flow meter detection).

[0038] Through the above method, while ensuring efficient oxidation, the operating cost is significantly reduced, and the design of ozone gradient concentration addition effectively inhibits the generation of by-products, ensuring the effect of subsequent waste gas treatment.

[0039] In summary, the waste gas generated by the production of anhydrous zinc chloride from zinc ash and zinc slag produced by industrial galvanizing after the above steps meets the following standards: the emission limit values in the secondary standard of the "Integrated Emission Standard of Air Pollutants" (GB16297-1996), with the measured dust content being 3.2 mg / m³ and HCl content being 2.1 mg / m³.

[0040] Experimental example Experimental methods: Experiment 1: Pollutant Removal Efficiency Verification; Conditions: Fixed exhaust gas flow rate of 8000 m³ / h, continuous operation for 72 hours; Sampling points: Spray tower inlet / outlet, primary plasma outlet, and secondary plasma outlet; Testing indicators: Dust: GB / T 16157-1996 gravimetric method; HCl: Mercuric thiocyanate spectrophotometry (HJ 549-2016); NH4Cl: Ion chromatography (HJ 799-2016); Zinc chloride: Zinc content determined by ICP-MS, converted to ZnCl2 concentration via stoichiometric conversion (HJ 776-2015); Ammonium chloride: Ion chromatography (HJ 800-2016 Appendix D). Experiment 2: Aerosol morphology analysis: Aerosol time-of-flight mass spectrometry (AMS) was used to monitor the morphology of ZnCl2-NH4Cl composite particles before and after plasma treatment. The volatile components of the particles were determined using a thermal fractionation differential mobility analyzer (TD-DMA). Experimental results and analysis: The pollutant removal effect (average) is shown in the following table: Aerosol morphology evolution: As can be seen from the above, the solution provided in this embodiment achieves targeted removal of zinc chloride: the spray tower alkali liquid achieves initial capture (removal rate 89.5%), and the plasma removal rate of escaping submicron ZnCl2 aerosol reaches 10.1%; 84.7% of NH4Cl is converted into ionic state in the spray tower, and the remaining 15.3% is decomposed by plasma oxidation.

[0041] Energy efficiency experiment: Comparison group settings Test conditions: Same gas volume: 8000m³ / h; same exhaust gas inlet concentration; continuous operation for 72 hours, recording steady-state data.

[0042] The energy consumption comparison data is shown in the following table: Under the same processing standards, the comprehensive energy consumption is reduced by 57.3% compared with traditional processes.

[0043] The comparison of processing costs is shown in the following table: The cost reduction is 68.2%, and when the annual processing volume reaches 20 million m³, 1.94 million yuan can be saved per year.

[0044] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A process for treating waste gas from natural gas combustion and acid mist generated by boiling regenerated acid in the production of zinc chloride from zinc ash and zinc slag, characterized in that: The following steps are involved: Step S1: natural gas incineration waste gas and acid mist waste gas are introduced into a spray tower, and subjected to dynamic alkali neutralization treatment and cooling treatment based on an intelligent pH value control method to obtain primary purified gas; wherein the spray tower adopts a double-layer cyclone spray, with a 10% NaOH solution in the upper layer and a 15% Na2CO3 solution in the lower layer; Step S2: The primary purified gas passes through a pipeline and enters a first-stage plasma dust removal and demisting device for processing to obtain a secondary purified gas; wherein the first-stage plasma dust removal and demisting device dynamically adjusts operating parameters based on VOCs online monitoring; Step S3: The secondary purified gas enters the secondary plasma dust removal and mist removal equipment for treatment to obtain the final treated tail gas, which meets the following standards: the emission limit values in the secondary standard of the "Integrated Emission Standard of Air Pollutants" (GB16297-1996).

2. The process for treating the waste gas from natural gas combustion and acid mist generated by boiling regenerated acid in the production of zinc chloride based on zinc ash and zinc slag according to claim 1, characterized in that: The specific implementation of the dynamic alkali neutralization treatment based on the pH value intelligent control method in step S1 is as follows: Step S1.1: introducing the acid mist waste gas and the natural gas incineration waste gas into a spray tower, and performing a gas-liquid contact reaction by spraying an alkaline solution in layers; Step S1.2: Real-time monitoring of pH values at different heights within the spray tower, wherein the upper region is maintained at pH 10.3-10.7, the middle region is maintained at pH 8.7-9.3, and the lower region is maintained at pH 7.0-8.0; Step S1.3: Based on the monitoring data of step S1.2, the dosage of NaOH and Na2CO3 solution is dynamically regulated by PID control; In step S1.3, when the pH value of the lower layer is detected to be less than 6.5 and lasts for more than time t, dosing is performed simultaneously: NaOH solution and Na2CO3 solution are added, and the dosing rate is increased to 150-200% of the baseline value.

3. The process for treating the waste gas from natural gas combustion and acid mist generated by boiling regenerated acid in the production of zinc chloride based on zinc ash and zinc slag according to claim 2, characterized in that: In step S1.2, three sets of online pH sensors are used to monitor the pH values of the upper, middle and lower reaction zones respectively. When the pH value difference between any two layers is greater than 0.5, the flow ratio of the upper layer spraying alkaline solution and the lower layer spraying alkaline solution is adjusted to be within the range of (1.5-2.5):

1.

4. The process for treating the waste gas from natural gas combustion and acid mist generated by boiling regenerated acid in the production of zinc chloride based on zinc ash and zinc slag according to claim 3, characterized in that: The PID control parameters in step S1.3 satisfy: (1) Proportional coefficient K p =2.2-2.8, integration time T i =15-25s, differential time T d =3-5s; (2) When the exhaust gas flow rate change rate is detected to be greater than 5% / min, adjust K p to 3.0-3.5, T i Shortened to 8-12s.

5. The process for treating the waste gas from natural gas combustion and acid mist generated by boiling regenerated acid in the production of zinc chloride based on zinc ash and zinc slag according to claim 4, characterized in that: The specific implementation of the first-level plasma dust removal and mist removal equipment in step S2 dynamically adjusting the working parameters based on VOCs online monitoring is as follows: Step S2.1: Based on the sensor array, real-time data on the pollutant concentration and composition of the primary purified gas is obtained; Step S2.2: Calculating the comprehensive pollution index I and the actual concentration C based on a data fusion algorithm that integrates photoionization detection values, infrared characteristic spectrum intensity, and differential sensor data; Step S2.3: Dynamically adjust the plasma field intensity parameters of the first-stage plasma dust and mist removal equipment based on the actual concentration C: when the actual concentration C is less than 50 mg / m³, the plasma operates at the baseline; when the actual concentration C is greater than or equal to 50 mg / m³, adjust the plasma electric field intensity U according to U=8+0.02×(C-50) kV / cm.

6. The process for treating the waste gas from natural gas combustion and acid mist generated by boiling regenerated acid in the production of zinc chloride based on zinc ash and zinc slag according to claim 5, characterized in that: In step S2.1, the sensor array includes: a photoionization detector; a Fourier transform infrared spectrometer; and three groups of differential gas sensors arranged axially along the pipeline.

7. The process for treating the waste gas from natural gas combustion and acid mist generated by boiling regenerated acid in the production of zinc chloride based on zinc ash and zinc slag according to claim 6, characterized in that: In step S2.2, the specific implementation of calculating the comprehensive pollution index I and the actual concentration C based on the data fusion algorithm is as follows: Step S2.2.1: Assigning reference weights to the photoionization detection value, infrared characteristic spectrum intensity and differential sensor data: Photoionization detection value PID: Weight = 0.6w; infrared characteristic peak intensity FTIR: weight = 0.3; Differential sensor data ΔS: weight = 0.1; Step S2.2.2: Dynamic weight adjustment strategy: When the ambient humidity is greater than 70%RH, the PID weight Reduced to 0.5, FTIR weight Increase to 0.4, or, when the gas velocity is greater than 3m / s, the ΔS weight Increase to 0.2, and reduce the remaining weights in proportion; obtain the final weight distribution based on the dynamic weight adjustment strategy; Step S2.2.3: Based on the final weight distribution, calculate the comprehensive pollution index I according to the following formula: ,in, is the absorbance of characteristic peak k, is the response factor of pollutant k; Step S2.2.4: Calculate the actual concentration: According to the formula = ,in, The upper limit of the range of the photoionization detector.

8. The process for treating the waste gas from natural gas combustion and acid mist generated by boiling regenerated acid in the production of zinc chloride based on zinc ash and zinc slag according to claim 7, characterized in that: The method further includes step S2.4: when the rate of change of the actual concentration C is greater than 10% / min, adjusting and extending the exhaust gas residence time in advance.

9. The process for treating waste gas from natural gas combustion and acid mist generated by boiling regenerated acid in the production of zinc chloride based on zinc ash and zinc slag according to claim 8, characterized in that: In step S3, the secondary purified gas is passed through the air duct into the secondary plasma dust removal and mist removal equipment, and ozone is added through the ozone generator along the flow direction of the secondary purified gas in the air duct, and the ozone concentration decreases from 150 ppm to 50 ppm.

10. The process for treating waste gas from natural gas combustion and acid mist generated by boiling regenerated acid in the production of zinc chloride based on zinc ash and zinc slag according to claim 9, characterized in that: In the ozone process, the ozone dosage is calculated according to the following formula: , where k is a coefficient ranging from 1.2 to 1.5, To detect the pollutant concentration of the secondary purified gas in real time, is the flow rate of secondary purge gas.

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