Preparation method of ammonia water for biological medicine

Abstract

The invention relates to the technical field of ammonia water preparation, in particular to a preparation method of ammonia water for biological medicine, which comprises the following steps: determining that liquid ammonia heat exchange treatment is qualified based on a liquid-gas two-phase density ratio of a gas-liquid mixture to obtain dry ammonia gas; acquiring the propagation sound velocity in the dry ammonia gas to determine whether the liquid ammonia entrainment reaches the standard or not; in response to the fact that the liquid ammonia entrainment amount does not reach the standard, the difference value between the propagation sound velocity and the preset propagation sound velocity is calculated to adjust the temperature of the plate heat exchanger and the liquid ammonia feeding amount, and the superheat degree of the dry ammonia gas is obtained to determine whether the liquid ammonia entrainment amount in the adjusted ammonia gas is reduced or not; executing mixed spraying in response to reduction of the liquid ammonia entrainment amount in the dry ammonia gas, and obtaining the organic carbon content of the mixed liquid and the ammonia gas loss coefficient of the escaped ammonia gas to determine whether the ammonia entrainment amount of ammonia water generated by mixed spraying reaches the standard or not; in response to the fact that the ammonia carrying amount does not reach the standard, the spraying pressure of pure water spraying or the proportion of the pure water amount of the mixed liquid obtained after mixed spraying is adjusted. The invention solves the problem of insufficient purity and stability of ammonia water.

Description

Technical Field

[0001] This invention relates to the field of ammonia preparation technology, and in particular to a method for preparing ammonia for biomedical use. Background Technology

[0002] Ammonia water, as a basic chemical, has wide applications in both industrial and pharmaceutical fields. Its preparation typically involves two core processes: liquid ammonia evaporation and vaporization, and ammonia absorption. However, existing preparation processes have significant shortcomings in quality monitoring and closed-loop control of key processes, making it difficult to reliably guarantee product purity, concentration stability, and production efficiency.

[0003] In the ammonia preparation process, traditional processes rely on fixed evaporation temperature and pressure parameters, or make rough judgments through manual observation. They cannot detect in real time and with sensitivity whether there are trace amounts of incompletely evaporated liquid ammonia droplets in the gas phase. Such entrainment makes it difficult to accurately control the ammonia concentration in subsequent absorption processes and may cause equipment liquid slugging risk.

[0004] In the ammonia absorption and ammonia water generation stages, existing technologies suffer from lag and bias in judging absorption efficiency and product concentration. The common practice is to perform offline sampling and analysis of the ammonia water in the storage tank after absorption to determine if the ammonia concentration meets the standards. This method cannot reflect changes during the absorption process in real time, and once a non-compliance is detected, the entire batch of products is irretrievably lost.

[0005] Chinese Patent Publication No. CN104355320A discloses a method for preparing ammonia water, comprising several heat exchangers and reactors: liquid nitrogen passes through a primary heat exchanger and is transported to a buffer tank via a conduit, generating gas; cooling water is introduced and discharged from the lower and upper ends of the primary heat exchanger, respectively; the generated gas is introduced through pipes into the side inlets of the primary and secondary reactors; soft water is introduced into the lower inlet of the primary reactor and then into the end inlet of the secondary heat exchanger from the upper outlet, and then into the lower inlet of the secondary reactor; the outlet of the secondary reactor produces finished ammonia water, which is then introduced into a tertiary heat exchanger; cooling water is introduced and discharged from the side inlet and outlet of the tertiary heat exchanger, respectively. This invention allows the finished ammonia water to be produced in only one process and can be automatically controlled; it uses a hollow capillary mixing unit, making the reaction more stable; it saves 10% energy and improves ammonia utilization compared to traditional processes.

[0006] Therefore, the aforementioned method for preparing ammonia water has the following problems: 1. The lack of monitoring of the amount of liquid ammonia entrained after the liquid ammonia is converted into gas makes it impossible to ensure that the ammonia entering the absorption system is in a dry state from the source.

[0007] 2. The lack of monitoring and adjustment of ammonia and soft water makes it difficult to ensure the stability and batch-to-batch consistency of the prepared ammonia water. Summary of the Invention

[0008] Therefore, the present invention provides a method for preparing ammonia water for biomedicine, which overcomes the problem of insufficient purity and stability of ammonia water due to the lack of monitoring of liquid ammonia entrainment in the prior art.

[0009] To achieve the above objectives, the present invention provides a method for preparing ammonia water for biomedical use, comprising: The density ratio of the liquid and gas phases of the gas-liquid mixture is used to determine the dry ammonia gas obtained after the liquid ammonia heat exchange treatment is qualified. The propagation speed of the dry ammonia gas is obtained and compared with the preset propagation speed to determine whether the amount of liquid ammonia entrained in the dry ammonia gas meets the standard. In response to the fact that the entrainment of liquid ammonia is not up to standard, the difference between the propagation speed of sound and the preset propagation speed of sound is calculated to adjust the temperature of the plate heat exchanger and the liquid ammonia feed rate in the liquid ammonia heat exchange treatment, and the superheat of the dry ammonia gas is obtained to determine whether the entrainment of liquid ammonia in the dry ammonia gas is reduced after adjustment. In response to the reduction in the amount of liquid ammonia entrained in the dried ammonia gas, the dried ammonia gas is conveyed to a super ammonia absorber to perform mixed spraying, and the organic carbon content of the mixed liquid and the ammonia loss coefficient of the ammonia gas escaping during the mixed spraying process are obtained to determine whether the ammonia carrying capacity of the ammonia water generated by the mixed spraying meets the standard. Adjust the spray pressure of pure water spraying or the proportion of pure water in the mixed solution of mixed spraying.

[0010] Furthermore, the qualification of the liquid ammonia heat exchange treatment is determined based on the fact that the density ratio of the liquid to gas phases is less than a preset density ratio of the liquid to gas phases.

[0011] Furthermore, the requirement that the amount of liquid ammonia entrained in the dried ammonia gas meets the standard is determined based on the propagation speed being greater than or equal to a preset propagation speed.

[0012] Furthermore, the fact that the amount of liquid ammonia entrained in the dried ammonia gas does not meet the standard is determined based on the fact that the propagation speed of sound is less than the preset propagation speed of sound.

[0013] Furthermore, in response to the condition that the liquid ammonia entrainment amount meets the standard, the process of determining whether the ammonia-carrying amount of the dried ammonia gas generated by pure water spraying meets the standard based on the temperature rise curve of the ammonia water during the pure water spraying process includes, Responding to the temperature rise rate in the temperature rise curve, and comparing the temperature rise rate with a preset temperature rise rate threshold; Based on the temperature rise rate being greater than or equal to a preset temperature rise rate threshold, it is determined that the ammonia carrying capacity of the ammonia water generated by the pure water spraying of the dried ammonia gas meets the standard. Based on the fact that the temperature rise rate is less than the preset temperature rise rate threshold, it is determined that the ammonia carrying capacity of the ammonia water generated by the pure water spraying of the dried ammonia gas does not meet the standard.

[0014] Furthermore, in response to the fact that the amount of liquid ammonia entrained is not up to standard, the temperature compensation amount of the plate heat exchanger is determined based on the difference between the propagation speed and the preset propagation speed to increase the heat medium flow rate of the plate heat exchanger, and the superheat of the dry ammonia is calculated. Based on the fact that the superheat of the dry ammonia is greater than or equal to the preset superheat threshold, it is determined that the amount of liquid ammonia entrained in the ammonia after adjustment is reduced.

[0015] Furthermore, the determination that the ammonia carrying capacity of the ammonia water generated by the mixed spraying is substandard is based on the organic carbon content being greater than or equal to a preset organic carbon content threshold, or the ammonia loss coefficient being greater than or equal to a preset ammonia loss coefficient.

[0016] Furthermore, the process of adjusting the spray pressure of the pure water spray in response to the ammonia carrying capacity failing to meet the standard includes, The spray pressure compensation amount is determined based on the absolute value of the difference between the temperature rise rate and the preset temperature rise rate threshold. Based on the spray pressure compensation amount, the pure water pump speed is increased to increase the spray pressure.

[0017] Furthermore, in response to the ammonia carrying capacity failing to meet the standard, the process of adjusting the pure water content of the mixed spray solution includes, The increase in the amount of pure water is determined based on the absolute value of the difference between the ammonia loss coefficient and the preset ammonia loss coefficient. Based on the increase in the amount of pure water, the opening of the pure water supply regulating valve is increased to increase the proportion of pure water in the mixture.

[0018] Furthermore, the ammonia carrying capacity of the ammonia water generated by the mixed spraying is determined based on the organic carbon content being less than a preset organic carbon content threshold, or the ammonia loss coefficient being less than a preset ammonia loss coefficient.

[0019] Compared with existing technologies, the advantages of this invention are as follows: This invention determines the heat exchange qualification of liquid ammonia based on the liquid-gas two-phase density ratio and combines this with real-time assessment of the amount of liquid ammonia entrained in the ammonia gas using sound velocity monitoring, thereby improving the control accuracy of ammonia purity and reducing process fluctuations caused by excessive liquid ammonia entrainment. When the amount of liquid ammonia entrained is insufficient, the evaporation parameters are adjusted in conjunction with the sound velocity difference and superheat feedback, avoiding the lag and deviation of traditional experience-based adjustments, thus reducing the risk of liquid ammonia residue and improving the stability of the evaporation process. By conveying the purified dry ammonia gas to a super ammonia absorber and performing mixed spraying, and determining the ammonia-carrying capacity of the ammonia water based on the organic carbon content and the escape ammonia loss coefficient, closed-loop control of the ammonia water generation process is achieved. For cases where the ammonia-carrying capacity is insufficient, adjusting the spray pressure or the mixed liquid ratio improves the concentration consistency and absorption efficiency of the ammonia water product, while reducing ammonia escape loss and raw material waste, thus enhancing the reliability of the preparation method.

[0020] Furthermore, by setting up a liquid-gas two-phase density ratio detection step for the gas-liquid mixture, the present invention can make real-time judgments on the dry ammonia gas at the outlet of the plate heat exchanger, which can identify the working condition of insufficient liquid ammonia evaporation. When the liquid-gas two-phase density ratio is found to be substandard, the ammonia absorption valve is closed and the gas-liquid mixture treated by liquid ammonia heat exchange is introduced into the dilute ammonia water recovery tank. This avoids ammonia gas containing unevaporated droplets from entering subsequent processes, eliminating the root cause of uncontrolled ammonia water concentration and uneven product quality caused by fluctuations in gas source purity. The diversion pipeline also improves the utilization rate of raw materials and reduces the direct venting and waste of materials.

[0021] Furthermore, this invention provides a technical means to control gas phase purity by introducing the detection and comparison of the propagation speed of sound in dry ammonia gas. The propagation speed of sound is sensitive to changes in medium density and state, and can effectively distinguish between pure ammonia gas and gas flow containing trace amounts of liquid ammonia. Compared with traditional indirect judgment methods that rely on temperature or pressure, the judgment based on sound speed has a faster response and improves the ability to capture the quality risks of liquid ammonia entrainment. When the propagation speed of sound does not meet the standard, it can identify that the amount of liquid ammonia entrained in dry ammonia gas is not up to standard, avoiding the entry of insufficiently pure ammonia gas into the super ammonia absorber. This reduces the risk of downstream processes experiencing fluctuations in ammonia water concentration and product non-compliance due to raw material gas quality issues, and provides a reliable process guarantee for obtaining high-purity ammonia water with stable concentration and uniform composition.

[0022] Furthermore, this invention improves the control accuracy and response speed of dried ammonia purity by dynamically adjusting the plate heat exchanger operating conditions based on the difference in sound velocity in response to substandard liquid ammonia entrainment and by verifying the superheat of ammonia. The adjustment process is precise and rapid by using a temperature compensation amount clearly defined by the sound velocity signal to regulate the heat transfer medium flow rate. This reduces the risk of process fluctuations caused by substandard dried ammonia entrained with liquid ammonia entering the downstream super ammonia absorber, and avoids problems such as unstable ammonia concentration and decreased absorption efficiency due to unqualified feed gas. By introducing superheat as a verification indicator for reducing liquid ammonia entrainment and reducing the liquid ammonia feed rate when liquid ammonia entrainment is not reduced, a dual regulation guarantee is formed, preventing the continuous generation of unqualified gas when a single adjustment method is ineffective.

[0023] Furthermore, this invention determines whether the ammonia-carrying capacity of the ammonia water generated by the mixed spraying meets the standard by monitoring the organic carbon content in the mixed liquid and the ammonia loss coefficient during the spraying process. This improves the comprehensiveness of the absorption efficiency of the ammonia water generation process, avoids misjudgment that may occur by relying on a single parameter, and reduces the risk of insufficient effective ammonia carrying capacity and product quality decline due to the content of ineffective or interfering organic matter in the mixed liquid.

[0024] Furthermore, this invention incorporates adjustment mechanisms in both pure water spraying and mixed spraying modes to address situations where ammonia carrying capacity falls short of standards. In pure water spraying, the spraying pressure is increased based on the temperature rise rate difference, improving the atomization degree and gas-liquid contact efficiency of the spray liquid, thereby increasing the ammonia absorption rate and preventing continuous inefficient operation due to insufficient absorption power. In mixed spraying, the pure water supply is increased based on the ammonia loss coefficient difference, reducing the ammonia concentration in the circulating absorbent, enhancing the absorption mass transfer driving force, avoiding increased ammonia escape losses due to absorbent saturation, improving the adaptability to fluctuations in different operating conditions, reducing the risk of substandard product concentration, and ensuring the stability and efficiency of the ammonia production process. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating the steps of a method for preparing ammonia water for biomedical use according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating the preparation process of ammonia water for biomedical use according to an embodiment of the present invention; Figure 3 A logic diagram for determining whether the amount of liquid ammonia entrained in dry ammonia gas meets the standard in an embodiment of the invention. Figure 4 This is a logic diagram for determining whether the ammonia-carrying capacity of the ammonia water generated by pure water spraying meets the standard in an embodiment of the present invention. Figure 5 This is a logic diagram for determining the reduction of liquid ammonia entrainment in dry ammonia gas in an embodiment of the present invention; In the diagram, 1-Liquid ammonia storage tank; 11-Plunger pump; 2-Plate heat exchanger; 21-Pressure transmitter; 22-Temperature sensor; 23-Ammonia absorption valve; 24-Recovery valve; 25-Ultrasonic transmitting probe; 26-Ultrasonic receiving probe; 3-Dilute ammonia water recovery tank; 4-Electric heating boiler; 42-Power pump; 43-Heating medium regulating valve; 5-Super ammonia absorber; 51-Temperature acquisition sensor; 52-Circulation pump; 53-Recovery pump; 54-Organic carbon measurement window; 55-Mixed liquid tank; 56-Ammonia concentration analyzer; 57-Pure water pump; 58-Pure water tank; 59-Tail gas recovery tank; 60-Gas flow meter; 6-Ammonia water outlet; 7-Pure water supply port; 71-Pure water supply regulating valve; 72-Switch valve. Detailed Implementation

[0026] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0027] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0028] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0029] Please see Figure 1 and Figure 2 As shown, Figure 1 This is a flowchart illustrating the steps of a method for preparing ammonia water for biomedical use according to an embodiment of the present invention. Figure 2 This is a flowchart illustrating the preparation process of ammonia water for biomedical use according to an embodiment of the present invention.

[0030] The present invention provides a method for preparing ammonia water for biomedical use, comprising: Step S1: Based on the density ratio of the liquid and gas phases of the gas-liquid mixture, determine the qualified liquid ammonia heat exchange treatment to obtain dry ammonia gas. Step S2: Obtain the propagation speed of the dry ammonia gas and compare it with the preset propagation speed to determine whether the amount of liquid ammonia entrained in the dry ammonia gas meets the standard. Step S3: In response to the liquid ammonia entrainment not meeting the standard, calculate the difference between the propagation speed and the preset propagation speed to adjust the temperature of the plate heat exchanger and the liquid ammonia feed rate in the liquid ammonia heat exchange treatment, and obtain the superheat of the dry ammonia gas to determine whether the liquid ammonia entrainment in the dry ammonia gas is reduced after adjustment. Step S4: In response to the reduction in the amount of liquid ammonia entrained in the dried ammonia gas, the dried ammonia gas is transported to a super ammonia absorber to perform mixed spraying, and the organic carbon content of the mixed liquid and the ammonia loss coefficient of the ammonia gas escaping during the mixed spraying process are obtained to determine whether the ammonia carrying capacity of the ammonia water generated by the mixed spraying meets the standard. Step S5: In response to the ammonia carrying capacity not meeting the standard, adjust the spray pressure of the pure water spray or the pure water volume ratio of the mixed solution in the mixed spray.

[0031] Specifically, this invention improves the accuracy of ammonia purity control and reduces process fluctuations caused by excessive liquid ammonia entrainment by determining the heat exchange qualification of liquid ammonia based on the liquid-gas two-phase density ratio and combining it with sound velocity monitoring to evaluate the amount of liquid ammonia entrained in the ammonia gas in real time. When the amount of liquid ammonia entrained is insufficient, the evaporation parameters are adjusted in linkage with the sound velocity difference and superheat feedback, avoiding the lag and deviation of traditional experience-based adjustments, thereby reducing the risk of liquid ammonia residue and improving the stability of the evaporation process. By transporting the purified ammonia gas to a super ammonia absorber and mixing and spraying it, and judging the ammonia carrying capacity of the ammonia water based on the organic carbon content and the escape ammonia loss coefficient, closed-loop control of the ammonia water generation process is achieved. For cases where the ammonia carrying capacity is insufficient, the concentration consistency and absorption efficiency of the ammonia water product are improved by adjusting the spray pressure or the mixed liquid ratio, while reducing ammonia escape loss and raw material waste, thus improving the reliability of the preparation method.

[0032] Specifically, the process of determining the suitability of liquid ammonia heat exchange treatment to obtain dry ammonia gas based on the density ratio of the liquid and gas phases of the gas-liquid mixture includes the following: The low-temperature liquid ammonia in the liquid ammonia storage tank is drawn into the plate heat exchanger by a plunger pump at a preset mass flow rate for liquid ammonia heat exchange treatment. In response to the liquid ammonia heat exchange treatment, the liquid ammonia absorbs heat in the flow channel of the plate heat exchanger to vaporize into a gas-liquid mixture, and the gas-liquid mixture is discharged from the outlet of the plate heat exchanger into a liquid-gas two-phase density ratio detection pipeline to determine whether the liquid ammonia heat exchange treatment is qualified. If the liquid-gas two-phase density ratio is greater than or equal to the preset liquid-gas two-phase density ratio, then the liquid ammonia heat exchange treatment is deemed qualified. If the density ratio of the liquid to gas phases is less than the preset density ratio, then the liquid ammonia heat exchange treatment is deemed unqualified.

[0033] In this embodiment of the invention, the liquid-gas two-phase density ratio is the ratio of the density of liquid ammonia to the density of ammonia gas in the gas-liquid mixture. The liquid ammonia density is determined based on the mass flow rate and temperature of liquid ammonia measured by instruments on the liquid ammonia feed pipeline. The ammonia gas density is determined based on the pressure and temperature of ammonia gas measured by pressure and temperature sensors as ammonia gas exits from the plate heat exchanger outlet and enters the liquid-gas two-phase density ratio detection pipeline. The liquid ammonia density and ammonia gas density are obtained by calling the ammonia property database function built into the control system (such as DCS or PLC), or by inputting the measured liquid ammonia temperature, ammonia gas pressure value, and temperature to the interface program of standard property calculation software (such as NIST REFPROP) for real-time calculation. The ammonia gas pressure value measured by the pressure sensor is the gauge pressure value. When calculating the ammonia gas density through the property database or software, it needs to be converted into an absolute pressure value for calculation, that is: absolute pressure (MPa) = gauge pressure (MPa) + local atmospheric pressure (approximately 0.1013MPa).

[0034] In this embodiment of the invention, the preset liquid-gas two-phase density ratio is determined to be within the range of [100, 300] based on the design pressure and design temperature of the ammonia gas at the outlet of the plate heat exchanger. It is preferably set to 200, which corresponds to the working condition where the design pressure of the plate heat exchanger outlet is 0.5MPa to 1.0MPa. However, the above value is not limited to this, and those skilled in the art can also adjust the value according to actual needs.

[0035] In this embodiment of the invention, the preset mass flow rate is in the range of [200 kg / h, 1000 kg / h], preferably set to 400 kg / h, but the above value is not limited to this, and those skilled in the art can adjust the value according to actual needs.

[0036] In this embodiment of the invention, dry ammonia gas is obtained based on the qualified heat exchange treatment of liquid ammonia.

[0037] Specifically, in response to the successful completion of the liquid ammonia heat exchange treatment, the ammonia absorption valve is activated to deliver the dry ammonia gas to the sound velocity detection pipeline and obtain the propagation speed of sound in the ammonia gas.

[0038] Specifically, in response to the failure of the liquid ammonia heat exchange treatment, the ammonia absorption valve is closed and the recovery valve is activated to introduce the gas-liquid mixture into a recovery tank containing a 5% to 15% dilute ammonia solution.

[0039] Specifically, this invention uses a liquid-gas two-phase density ratio detection step to monitor the dry ammonia gas at the outlet of the plate heat exchanger in real time. This allows for the identification of insufficient liquid ammonia evaporation. When the liquid-gas two-phase density ratio is found to be substandard, the ammonia absorption valve is closed and the liquid-gas mixture treated by the liquid ammonia heat exchange is introduced into a dilute ammonia water recovery tank. This prevents ammonia gas containing unevaporated droplets from entering subsequent processes, eliminating the root cause of uncontrolled ammonia water concentration and uneven product quality due to fluctuations in gas source purity. The diversion pipeline also improves the utilization rate of raw materials and reduces direct venting and waste of materials.

[0040] Please see Figure 3 As shown, it is a logic diagram for determining whether the amount of liquid ammonia entrained in dry ammonia gas meets the standard in an embodiment of the present invention.

[0041] Specifically, the process of obtaining the propagation velocity of sound in the dried ammonia gas and comparing it with a preset propagation velocity to determine whether the amount of liquid ammonia entrained in the dried ammonia gas meets the standard includes: If the propagation speed of sound is greater than or equal to the preset propagation speed of sound, then the amount of liquid ammonia entrained in the dry ammonia gas is determined to meet the standard. If the propagation speed of sound is less than the preset propagation speed of sound, then the amount of liquid ammonia entrained in the dry ammonia gas is determined to be substandard.

[0042] In this embodiment of the invention, the propagation speed of the dry ammonia gas is measured by a sound velocity detector based on the ultrasonic time-of-flight method, which is installed on the sound velocity detection pipeline. The sound velocity detector has ultrasonic transmitting probes and ultrasonic receiving probes installed in pairs on both sides of the pipeline, forming a set of measurement channels with a precise known distance. During measurement, the ultrasonic transmitting probes sequentially emit high-frequency ultrasonic pulses and measure the propagation time (t1) in the downstream direction and the propagation time (t2) in the upstream direction in the dry ammonia gas medium. The propagation speed of the dry ammonia gas is calculated according to the formula: propagation speed = distance / 2 × (1 / t1 + 1 / t2). At the same time, the real-time temperature and pressure values ​​of the dry ammonia gas are obtained.

[0043] In this embodiment of the invention, based on the real-time temperature and pressure values ​​of the dry ammonia gas, a function of standard physical property calculation software (such as NIST REFPROP) is called to calculate the theoretical sound velocity corresponding to pure dry ammonia gas under the current temperature and pressure conditions. The theoretical sound velocity is multiplied by a preset safety factor to obtain the preset propagation sound velocity. The preset safety factor is an engineering margin used to compensate for measurement system errors and allow for the influence of trace background gases. Its value range is [0.98, 0.995], preferably set to 0.99. The value range of the preset propagation sound velocity determined by this method corresponds to the operating conditions of the plate heat exchanger outlet design pressure (gauge pressure) of 0.5MPa to 1.0MPa and temperature of 30℃ to 80℃. Those skilled in the art can calculate the theoretical sound velocity and determine the preset safety factor according to the actual design conditions, thereby determining the preset propagation sound velocity.

[0044] Specifically, this invention provides a technical means to control gas phase purity by introducing the detection and comparison of the propagation speed of sound in dry ammonia gas. The propagation speed of sound is sensitive to changes in medium density and state, and can effectively distinguish between pure ammonia gas and gas flow containing trace amounts of liquid ammonia. Compared with traditional indirect judgment methods that rely on temperature or pressure, the judgment based on sound speed has a faster response and improves the ability to capture the quality risks of liquid ammonia entrainment. When the propagation speed of sound does not meet the standard, it can identify that the amount of liquid ammonia entrained in dry ammonia gas is not up to standard, thus preventing insufficiently pure ammonia gas from entering the super ammonia absorber. This reduces the risk of downstream processes experiencing fluctuations in ammonia concentration and product defects due to raw material gas quality issues, and provides a reliable process guarantee for obtaining high-purity ammonia water with stable concentration and uniform composition.

[0045] Please see Figure 4 As shown, it is a logic diagram for determining whether the ammonia content of the ammonia water generated by pure water spraying meets the standard in an embodiment of the present invention.

[0046] Specifically, in response to the liquid ammonia entrainment reaching the standard, the dried ammonia gas is transported to a super ammonia absorber to perform pure water spraying, and the temperature rise curve of the ammonia water during the pure water spraying process within a preset period is obtained to determine whether the ammonia-carrying capacity of the dried ammonia gas in the pure water spraying process meets the standard. Responding to the temperature rise rate in the temperature rise curve, and comparing the temperature rise rate with a preset temperature rise rate threshold; If the temperature rise rate is greater than or equal to the preset temperature rise rate threshold, then it is determined that the ammonia carrying capacity of the ammonia water generated by the pure water spraying of the dried ammonia gas meets the standard. If the temperature rise rate is less than the preset temperature rise rate threshold, it is determined that the ammonia carrying capacity of the ammonia water generated by the pure water spraying of the dried ammonia gas does not meet the standard.

[0047] In this embodiment of the invention, a temperature acquisition sensor is set to continuously acquire the temperature value at the bottom of the super ammonia absorber at fixed time intervals (e.g., 1 second) within the preset period, and the acquired temperature value is transmitted to a PLC or DCS to form the temperature rise curve of the ammonia water.

[0048] In this embodiment of the invention, the preset temperature rise rate threshold ranges from [0.5℃ / s to 3.0℃ / s], preferably set to 1.5℃ / s. However, the above value is not limited to this, and those skilled in the art can adjust the value according to actual needs.

[0049] In this embodiment of the invention, the preset period ranges from [10s, 300s], preferably set to 60s, but the above value is not limited to this, and those skilled in the art can adjust the value according to actual needs.

[0050] In this embodiment of the invention, ammonia water continuously releases heat during dissolution in water, and the molar enthalpy of dissolution (ΔH) is constant. According to the law of conservation of energy, in an adiabatic or near-adiabatic super ammonia absorber, all the heat released during dissolution is used to heat the spray liquid. The heat release power (Q) per unit time is equal to the product of the amount of ammonia carried (molar flow rate of ammonia, n) and the absolute value of the enthalpy of dissolution, Q=n×|ΔH|. The heat released by the dissolution of ammonia per unit time is equal to the enthalpy increase caused by the heat absorbed by the pure water spray liquid. The heat release power and the temperature rise rate (dT / dt) of the spray liquid (water) are related through its mass flow rate (m) and specific heat capacity (C), Q=m×C×(dT / dt). From the above formula, it can be concluded that the amount of ammonia carried is proportional to the temperature rise rate. Therefore, the preset temperature rise rate threshold corresponds to the critical amount of ammonia carried necessary to maintain the target productivity and concentration.

[0051] In this embodiment of the invention, the super ammonia absorber integrates a temperature sensor, organic carbon monitoring, exhaust gas composition and flow monitoring, and a closed-loop control system that is linked with the pump and valve actuator.

[0052] Please see Figure 5 As shown, it is a logic diagram for determining the reduction of liquid ammonia entrainment in dry ammonia gas according to an embodiment of the present invention.

[0053] Specifically, in response to the insufficient amount of liquid ammonia entrainment, the process of calculating the difference between the propagation speed of sound and the preset propagation speed of sound to adjust the temperature of the plate heat exchanger in the liquid ammonia heat exchange treatment, and obtaining the superheat of the dried ammonia gas to determine whether the amount of liquid ammonia entrainment in the dried ammonia gas has decreased after adjustment includes, The temperature compensation amount of the plate heat exchanger is determined based on the difference, and the heat medium flow rate of the plate heat exchanger is increased based on the temperature compensation amount to reduce the amount of liquid ammonia entrained in the ammonia gas. Obtain the temperature and pressure values ​​of ammonia gas, and calculate the superheat of the ammonia gas; If the superheat of the dried ammonia gas is greater than or equal to the preset superheat threshold, then it is determined that the amount of liquid ammonia entrained in the dried ammonia gas is reduced after adjustment. If the superheat of the dried ammonia gas is less than the preset superheat threshold, it is determined that the amount of liquid ammonia entrained in the dried ammonia gas after adjustment has not decreased.

[0054] In this embodiment of the invention, the process of obtaining the temperature compensation amount is as follows: the difference between the sound velocity of dry ammonia propagation and the preset sound velocity is calculated and multiplied by the preset temperature compensation coefficient to obtain the temperature compensation amount of the plate heat exchanger. The preset temperature compensation coefficient represents the temperature value (unit: ℃·s / m) required to compensate for each unit sound velocity difference. The preset temperature compensation coefficient is calibrated through active disturbance experiments during the process debugging stage, and the preferred value range is set to [0.2℃·s / m, 1.5℃·s / m].

[0055] In this embodiment of the invention, the process of increasing the heat medium flow rate of the plate heat exchanger is as follows: based on the temperature compensation amount, the opening of the heat medium regulating valve on the heat medium inlet pipe of the plate heat exchanger is increased to increase the flow rate of steam or high-temperature hot water and thus increase the heat transfer temperature of the plate heat exchanger. The increase in the opening of the heat medium regulating valve is proportional to the temperature compensation amount.

[0056] In this embodiment of the invention, the superheat is calculated as follows: a temperature sensor (such as a PT100 platinum resistance thermometer) and a pressure transmitter are installed in the dry ammonia outlet pipe of the plate heat exchanger to measure the actual temperature and pressure of the outlet dry ammonia. Based on the Antoine equation saturation temperature = 1474.0 / [6.494 - ln(actual pressure × 0.01)] - 243.0, the saturation temperature of the pure ammonia at the actual pressure is obtained. The superheat of the dry ammonia is the difference between the actual temperature and the saturation temperature.

[0057] In this embodiment of the invention, the preset superheat threshold value ranges from [3℃ to 15℃], preferably set to 5℃. However, the above value is not limited to this, and those skilled in the art can adjust the value according to actual needs.

[0058] Specifically, in response to the fact that the amount of liquid ammonia entrained in the dried ammonia gas does not decrease after the adjustment of the excessive heat of the dried ammonia gas, it is determined to reduce the amount of liquid ammonia feed, wherein the amount of reduction in the amount of liquid ammonia feed is determined based on the difference between the excessive heat and the preset excessive heat.

[0059] In this embodiment of the invention, the process of determining the reduction in liquid ammonia feed is as follows: based on the determination that the amount of liquid ammonia entrained after adjustment has not decreased due to the superheat, the product of the difference between the current superheat and the preset superheat threshold and the preset feed rate adjustment coefficient is calculated to obtain the percentage reduction in the speed of the plunger pump on the liquid ammonia feed pipeline. The feed rate adjustment coefficient (unit: %·℃) -1 During process debugging, the value range was determined to be [1.0% °C]. -1 5.0% °C -1 It can be adjusted according to the changes in superheat after regulation to form a closed-loop control.

[0060] Specifically, this invention improves the control accuracy and response speed of dried ammonia purity by dynamically adjusting the plate heat exchanger operating conditions based on the difference in sound velocity in response to substandard liquid ammonia entrainment and by verifying the superheat of the ammonia gas. The adjustment process is precise and rapid by using a temperature compensation amount clearly defined by the sound velocity signal to regulate the heat transfer medium flow rate. This reduces the risk of process fluctuations caused by substandard dried ammonia entrainment entering the downstream super ammonia absorber and avoids problems such as unstable ammonia concentration and decreased absorption efficiency due to unqualified feed gas. Furthermore, by introducing superheat as a verification indicator for reducing liquid ammonia entrainment and reducing the liquid ammonia feed rate when the entrainment is not reduced, a dual regulation guarantee is formed, preventing the continuous generation of unqualified gas when a single adjustment method is ineffective.

[0061] Specifically, in response to the reduction in the amount of liquid ammonia entrained in the dried ammonia gas, the dried ammonia gas is conveyed to a super ammonia absorber to perform a mixed spraying, and the organic carbon content of the mixed liquid and the ammonia loss coefficient of the ammonia gas escaping during the mixed spraying process are obtained to determine whether the ammonia-carrying capacity of the ammonia water generated by the mixed spraying meets the standard. If the organic carbon content is less than the preset organic carbon content threshold and the ammonia loss coefficient is less than the preset ammonia loss coefficient, then it is determined that the ammonia carrying capacity of the ammonia water generated by the mixed spraying meets the standard. If the organic carbon content is greater than or equal to the preset organic carbon content threshold, or the ammonia loss coefficient is greater than or equal to the preset ammonia loss coefficient, then it is determined that the ammonia carrying capacity of the ammonia water generated by the mixed spraying is substandard.

[0062] In this embodiment of the invention, the mixing and spraying process involves introducing dry ammonia gas through the bottom inlet of the super ammonia absorber and starting the circulation pump to uniformly spray the mixture downwards from the spray head located at the top of the tower. This ensures that the dry ammonia gas and the mixture have sufficient counter-current contact within the tower space, and any unabsorbed exhaust gas is discharged from the top of the tower. The sprayed mixture is collected at the bottom of the tower; a portion is drawn off as product, and the other portion is returned to the mixture tank via a recovery pump to be mixed with freshly replenished mixture for further mixing and spraying.

[0063] In this embodiment of the invention, the mixture is a solution prepared by mixing pure water and dilute ammonia water with a concentration of 5% to 15% in a volume ratio of 1:1 to 4:1, wherein the pure water is water that meets the "water for injection" standard in the Pharmacopoeia of the People's Republic of China.

[0064] In this embodiment of the invention, the process of obtaining the organic carbon content is as follows: an online total organic carbon analyzer is installed in the circulation pipeline of the mixture. A small amount of the mixture sample is extracted through the pipeline where the organic carbon measurement window is located. After passing through acidification and gas stripping to remove inorganic carbon, the organic carbon is converted into carbon dioxide using methods such as high-temperature catalytic oxidation. The concentration of carbon dioxide is then measured by a conductivity detector to obtain the organic carbon content value of the mixture.

[0065] In this embodiment of the invention, the process of obtaining the ammonia loss coefficient is as follows: an ammonia concentration analyzer is installed on the gas outlet pipe at the top of the super ammonia absorber to measure the volume concentration of ammonia in the exhaust gas in real time, and the exhaust gas operating condition volumetric flow rate (unit Nm³) is obtained according to the installed thermal gas flow meter. 3 The mass flow rate of ammonia escaping per unit time is obtained by multiplying the ammonia volume concentration and the operating volume flow rate with the ammonia density. The ammonia loss coefficient is calculated as (mass flow rate of escaping ammonia / total mass flow rate of ammonia input to the super ammonia absorber) × 100%.

[0066] In this embodiment of the invention, the preset organic carbon content threshold ranges from [0.1 mg / L, 0.5 mg / L], preferably set to 0.5 mg / L, and the preset ammonia loss coefficient ranges from [0.5%, 2.0%], preferably set to 1.0%. However, the above values ​​are not limited to these, and those skilled in the art can adjust the values ​​according to actual needs.

[0067] Specifically, this invention determines whether the ammonia-carrying capacity of the ammonia water generated by mixed spraying meets the standard by jointly monitoring the organic carbon content in the mixed liquid and the ammonia loss coefficient during the spraying process. This improves the comprehensiveness of the absorption efficiency of the ammonia water generation process, avoids misjudgment that may occur by relying on a single parameter, and reduces the risk of insufficient effective ammonia carrying capacity and product quality decline due to the content of ineffective or interfering organic matter in the mixed liquid.

[0068] Specifically, in response to the ammonia carrying capacity meeting the standard, a batch of qualified ammonia water is produced.

[0069] Specifically, the process of adjusting the spray pressure during pure water spraying based on the absolute value of the difference between the temperature rise rate and a preset temperature rise rate threshold in response to the ammonia carrying capacity failing to meet the standard includes the following steps: The spray pressure compensation amount is determined based on the absolute value to increase the spray pressure during the pure water spraying process; Based on the spray pressure compensation amount, the pure water pump speed is increased to increase the spray pressure.

[0070] In this embodiment of the invention, the spray pressure compensation amount is obtained by multiplying the absolute value of the difference between the temperature rise rate and the preset temperature rise rate threshold with a preset pressure compensation coefficient. The pressure compensation coefficient represents the pressure value required to compensate for each unit temperature rise rate difference, such as 1℃ / s. The pressure compensation coefficient is calibrated through a step test, and the value range of the pressure compensation coefficient is [0.02MPa·s / ℃, 0.10MPa·s / ℃].

[0071] In this embodiment of the invention, the process of increasing the speed of the pure water pump is determined by multiplying the ratio of 0.5 times the spray pressure compensation amount to the current pressure value by 100%.

[0072] Specifically, in response to the ammonia carrying capacity failing to meet the standard, the process of determining the proportion of pure water in the mixed spray solution based on the absolute value of the difference between the ammonia loss coefficient and the preset ammonia loss coefficient includes the following steps: The increase in the amount of pure water is determined based on the absolute value of the difference between the ammonia loss coefficient and the preset ammonia loss coefficient. Based on the increase in the amount of pure water, the opening of the pure water supply regulating valve is increased to increase the proportion of pure water in the mixture.

[0073] In this embodiment of the invention, the process of determining the increase in the amount of pure water is as follows: the increase in the pure water flow rate is obtained by multiplying the absolute value of the difference between the ammonia loss coefficient and the preset ammonia loss coefficient with the preset flow rate adjustment coefficient.

[0074] In this embodiment of the invention, the flow rate adjustment coefficient represents the increase in pure water flow rate required per unit loss coefficient difference. This flow rate adjustment coefficient is calibrated during the process debugging phase based on the total flow rate of the mixed liquor circulation and the flow characteristics of the pure water supply regulating valve, and its value range is set to [2.0, 10.0] L·min. -1 ·% -1 .

[0075] In this embodiment of the invention, the process of increasing the opening of the pure water supply regulating valve is as follows: based on the increase in the amount of pure water, the opening of the pure water regulating valve installed on the pure water supply pipeline is increased to allow more fresh pure water to enter the mixed liquid circulation, thereby increasing the proportion of pure water in the mixed liquid.

[0076] Specifically, this invention incorporates adjustment mechanisms in both pure water spraying and mixed spraying modes to address situations where ammonia carrying capacity falls short of standards. In pure water spraying, the spraying pressure is increased based on the temperature rise rate difference, improving the atomization degree and gas-liquid contact efficiency of the spray liquid, thereby increasing the ammonia absorption rate and preventing continuous inefficient operation due to insufficient absorption power. In mixed spraying, the pure water supply is increased based on the ammonia loss coefficient difference, reducing the ammonia concentration in the circulating absorbent, enhancing the absorption mass transfer driving force, avoiding increased ammonia escape losses due to absorbent saturation, improving adaptability to fluctuations in different operating conditions, reducing the risk of substandard product concentration, and ensuring the stability and efficiency of the ammonia production process.

[0077] Please continue reading. Figure 2As shown in the embodiment of the present invention, the workflow of the ammonia water preparation method is as follows: Low-temperature liquid ammonia is pressurized from the liquid ammonia storage tank 1 by a plunger pump 11 and then transported to the liquid ammonia flow channel of the plate heat exchanger 2. There, it undergoes countercurrent heat exchange with high-temperature water from the electric heating boiler 4, which is then transported to the heat medium inlet of the plate heat exchanger 2 by a power pump 42 and controlled by a heat medium regulating valve 43. The liquid ammonia absorbs heat and vaporizes into dry ammonia gas. The dry ammonia gas first enters the liquid-gas two-phase density ratio detection pipeline, where a pressure transmitter 21 and a temperature sensor 22 measure the pressure and temperature of the dry ammonia gas. The density ratio of the liquid to gas phases is calculated. If the density ratio meets the standard, the ammonia absorption valve 23 is opened, allowing dry ammonia gas to enter the sound velocity detection pipeline. The ultrasonic transmitting probe 25 and ultrasonic receiving probe 26 measure the propagation sound velocity to verify the dryness purity of the ammonia gas. If the standard is not met, the ammonia absorption valve 23 is closed and the recovery valve 24 is opened, guiding the unqualified dry ammonia gas containing droplets into the dilute ammonia water recovery tank 3. The dry ammonia gas that passes the sound velocity verification is sent to the bottom of the super ammonia absorber 5. In pure water spray mode, it is supplied through the pure water supply port 7. Water for injection stored in pure water tank 58 is pressurized by pure water pump 57 and sprayed down from the top of the column, where it comes into countercurrent contact with rising ammonia gas to generate ammonia water. Temperature sensor 51 continuously monitors the temperature of the ammonia water at the bottom of the column, generating a temperature rise curve based on the ammonia water temperature to calculate the temperature rise rate and determine if the ammonia carrying capacity meets the standard. If it does not meet the standard, the spray pressure is increased by increasing the speed of pure water pump 57. In mixed spray mode, pure water and dilute ammonia water mixed in proportion in mixing tank 55 are transported to the top of the column for spraying by circulating pump 52, and then collected at the bottom of the column. The liquid is returned to the mixing tank 55 by the recovery pump 53. The online total organic carbon analyzer monitors the organic carbon content of the circulating liquid through the organic carbon measurement window 54. The ammonia concentration analyzer 56 and the gas flow meter 60 at the top of the tower monitor the ammonia loss coefficient to determine whether the ammonia carrying capacity meets the standard. If the ammonia carrying capacity does not meet the standard, the proportion of pure water in the mixed liquid is increased by increasing the opening of the pure water supply regulating valve 71. The unabsorbed tail gas enters the tail gas recovery tank 59. The ammonia water product with both concentration and purity meeting the standards is output from the ammonia water outlet 6, completing the preparation of one batch.

[0078] Example 1: Continuous production testing was conducted using the present invention, and the test results are shown in Table 1.

[0079] Comparative Example 1 The production method employs traditional fixed parameters and offline control without any monitoring.

[0080] In this embodiment of the invention, the amount of liquid ammonia entrained is determined by the low-temperature cold trap collection-weighing method, the ammonia purity is determined by gas chromatography, the batch-to-batch concentration RSD is determined by continuously producing 5 independent batches, testing each batch of finished product according to the ammonia content method, calculating the relative standard deviation of the ammonia content data, the ammonia content (mass fraction) is determined by acid-base titration, and the total organic carbon content is determined by TOC meter measurement.

[0081] Table 1 Test Results

[0082] In the embodiments of the present invention, the amount of liquid ammonia entrained and the purity of ammonia in Example 1 verify the effectiveness of the dual online monitoring and control mechanism of liquid-gas two-phase density ratio and propagation speed of sound adopted in the present invention, ensuring that the ammonia entering the super ammonia absorber is in a dry and pure state, overcoming the raw material gas quality fluctuation and liquid ammonia entrainment risk caused by the lack of real-time monitoring in Comparative Example 1.

[0083] In the embodiments of the present invention, the batch-to-batch concentration RSD and ammonia content control range of Example 1 are better than those of Comparative Example 1, which proves that the closed-loop control strategy introduced in the absorption stage of the present invention can compensate for fluctuations in the production process in real time and achieve precise and stable control of ammonia concentration.

[0084] In this embodiment of the invention, compared with the traditional production method with fixed parameters and offline control, the present invention improves the dryness purity of ammonia gas, the concentration consistency and chemical purity of the finished ammonia solution, and solves the problem of insufficient purity and stability of ammonia solution.

[0085] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing ammonia water for biomedical use, characterized by, The method comprises: determining the dry ammonia gas after the heat exchange treatment of liquid ammonia based on the ratio of the liquid-gas two-phase density of the gas-liquid mixture; obtaining the propagation speed of the dry ammonia gas and comparing it with the preset propagation speed to determine whether the liquid ammonia entrainment in the dry ammonia gas meets the standard; in response to the liquid ammonia entrainment not meeting the standard, calculating the difference between the propagation speed and the preset propagation speed to adjust the temperature of the plate heat exchanger and the liquid ammonia feed quantity in the heat exchange treatment of liquid ammonia, and obtaining the superheat degree of the dry ammonia gas to determine whether the liquid ammonia entrainment in the dry ammonia gas after the adjustment is reduced; in response to the reduction of the liquid ammonia entrainment in the dry ammonia gas, transporting the dry ammonia gas to the super-ammonia absorber to perform mixed spraying, and obtaining the organic carbon content of the mixed liquid and the ammonia loss coefficient of the escaped ammonia gas in the mixed spraying process to determine whether the ammonia carrying capacity of the ammonia water generated by the mixed spraying meets the standard; in response to the ammonia carrying capacity not meeting the standard, adjusting the spraying pressure of the pure water spraying or the pure water quantity proportion of the mixed liquid in the mixed spraying.

2. The method of claim 1, wherein the ammonia water is prepared by the process of claim 1. The heat exchange treatment of liquid ammonia meeting the standard is determined based on the ratio of the liquid-gas two-phase density being less than the preset ratio of the liquid-gas two-phase density.

3. The method of claim 1, wherein the ammonia water is prepared by the process of claim 1, and the ammonia water is used for biological medicine. The liquid ammonia entrainment in the dry ammonia gas meeting the standard is determined based on the propagation speed being greater than or equal to the preset propagation speed.

4. The method of claim 1, wherein the ammonia water is prepared by the process of claim 1. The liquid ammonia entrainment in the dry ammonia gas not meeting the standard is determined based on the propagation speed being less than the preset propagation speed.

5. The method of claim 3, wherein the ammonia water is prepared by the process of claim 1 or 2. in response to the liquid ammonia entrainment meeting the standard, the process of determining whether the ammonia carrying capacity of the ammonia water generated by the pure water spraying of the dry ammonia gas meets the standard based on the temperature rise curve of the ammonia water in the pure water spraying process comprises, in response to the temperature rise rate in the temperature rise curve, and comparing the temperature rise rate with the preset temperature rise rate threshold; based on the temperature rise rate being greater than or equal to the preset temperature rise rate threshold, determining that the ammonia carrying capacity of the ammonia water generated by the pure water spraying of the dry ammonia gas meets the standard; based on the temperature rise rate being less than the preset temperature rise rate threshold, determining that the ammonia carrying capacity of the ammonia water generated by the pure water spraying of the dry ammonia gas does not meet the standard.

6. The method of claim 4, wherein the ammonia water is prepared by the process of claim 1 or 2. in response to the liquid ammonia entrainment not meeting the standard, determining the temperature compensation quantity of the plate heat exchanger based on the difference between the propagation speed and the preset propagation speed to increase the heat medium flow of the plate heat exchanger, and calculating the superheat degree of the dry ammonia gas, based on the superheat degree of the dry ammonia gas being greater than or equal to the preset superheat degree threshold, determining that the liquid ammonia entrainment in the ammonia gas after the adjustment is reduced.

7. The method of claim 6, wherein the ammonia water is prepared by the process of claim 1 or 2. The ammonia carrying capacity of the ammonia water generated by the mixed spraying not meeting the standard is determined based on the organic carbon content being greater than or equal to the preset organic carbon content threshold, or the ammonia loss coefficient being greater than or equal to the preset ammonia loss coefficient.

8. The method of claim 5, wherein the ammonia water is prepared by the process of claim 1 or 2. in response to the ammonia carrying capacity not meeting the standard, the process of adjusting the spraying pressure of the pure water spraying comprises, determining the spraying pressure compensation quantity based on the absolute value of the difference between the temperature rise rate and the preset temperature rise rate threshold; based on the spraying pressure compensation quantity, determining to increase the pure water pump speed to increase the spraying pressure.

9. The method of claim 7, wherein the ammonia water is prepared by the process of claim 1 or 2. in response to the ammonia carrying capacity not meeting the standard, the process of adjusting the pure water quantity proportion of the mixed liquid in the mixed spraying comprises, determining the increase quantity of the pure water quantity based on the absolute value of the difference between the ammonia loss coefficient and the preset ammonia loss coefficient; based on the increase quantity of the pure water quantity, determining to increase the opening degree of the pure water supply adjusting valve to increase the pure water quantity proportion of the mixed liquid.

10. The method of claim 7, wherein the ammonia water is prepared by the process of claim 1. The execution of the mixed spraying to generate ammonia water is based on the organic carbon content being less than a preset organic carbon content threshold or the ammonia gas loss coefficient being less than a preset ammonia gas loss coefficient.

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