A system and process for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water

Abstract

This invention discloses a system and process for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water, relating to the field of chemical technology. The invention includes an acidic water buffer tank, a clay tank, a steam heater, an ammonium chloride crystallization washing tank, and an ammonium sulfide circulating absorption tower arranged sequentially along the material flow direction. The acidic water, after being treated with clay to remove colloids, floating oil, and large molecular organic impurities, is heated and sent to the crystallization washing tank. At 60–70°C and -0.07–-0.09 MPa, flash evaporation causes static crystallization of ammonium chloride. The material at the bottom of the tank is diverted to an ammonium chloride aqueous solution buffer tank and a low-concentration acidic water buffer tank. Ammonia gas escaping from the top of the tank, mixed with hydrogen sulfide, is sent to the absorption tower via a dry vacuum pump, where it reacts countercurrently with the circulating spray liquid to generate ammonium sulfide. This invention, through clay impurity removal, dual-parameter coupled control, static crystallization desalination, differential pressure interlocking automatic switching, and low-temperature absorption locking, can adapt to complex water qualities with high sulfur, high nitrogen, and high chlorine levels, simultaneously producing industrial-grade ammonium chloride aqueous solution and ammonium sulfide aqueous solution with a mass fraction of 8%–20%.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, and in particular relates to a system for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water. Background Technology

[0002] During the hydrorefining process of waste tire oil, waste plastic oil, and other petroleum products, large amounts of organic sulfur, organic nitrogen, and organic chlorine in the raw materials are converted into hydrogen sulfide, ammonia, and chloride ions. The resulting acidic water is characterized by extremely high levels of ammonia nitrogen, extremely high levels of sulfides, high chloride ion content, and complex impurity components. This acidic water mainly originates from industrial production processes such as petroleum refining, coal chemical industry, coking, and natural gas processing. Direct discharge of such water will not only cause serious harm to the ecological environment but also lead to the waste of valuable sulfur and ammonia resources.

[0003] Currently, the main technical routes in the fields of acidic water treatment and ammonium sulfide preparation are as follows:

[0004] I. Direct Synthesis Method Using Purchased Raw Materials

[0005] (1) Sodium sulfide and ammonium chloride metathesis method:

[0006] The reaction principle is Na2S + 2NH4Cl → (NH4)2S + 2NaCl. This method requires the preparation of a 1-2 mol / L aqueous solution of sodium sulfide and ammonium chloride, which is slowly mixed and reacted under ice bath conditions (0-5℃). After filtration to remove NaCl, the product is concentrated under vacuum at low temperature (≤40℃) to obtain ammonium sulfide. This method has a mild reaction, simple equipment, and high product purity, but the raw material cost is high (industrial-grade sodium sulfide and ammonium chloride need to be purchased externally), a large amount of NaCl salt residue is produced as a by-product, acidic wastewater cannot be utilized, and the production scale is small and intermittent, making it difficult to achieve large-scale continuous production.

[0007] (2) Sodium sulfide reacts with acid to generate H2S, which is then absorbed by ammonia water:

[0008] The reaction principle is Na2S + 2HCl → 2NaCl + H2S, H2S + 2NH3·H2O → (NH4)2S + 2H2O. The process is as follows: industrial sodium sulfide is added to hydrochloric acid or sulfuric acid to generate H2S gas. After being washed and purified by water, 8% to 10% ammonia water by mass is introduced until saturation (NH4HS is generated first). Then, it is mixed with an equal volume of ammonia water to generate (NH4)2S. The concentration is adjusted to 16.5% to 20% to obtain the finished product. This method has mature technology and stable product concentration, but it is completely dependent on purchased sodium sulfide and ammonia water. It cannot make resource utilization of acidic wastewater, generates additional waste salt, the system has insufficient airtightness, the risk of H2S leakage is relatively large, and it is mostly an intermittent operation with low degree of automation.

[0009] (3) High-temperature reduction of ammonia and sulfur: The reaction principle is 2NH3+S→(NH4)2S (requires H2 / CO reducing atmosphere and catalyst). Under the conditions of 200~300℃ and 0.5~1MPa, NH3 and sulfur vapor undergo a catalytic reaction to first generate H2S intermediate, which is then absorbed by NH3. After condensation and multi-stage absorption, ammonium sulfide solution is obtained. This method can be operated continuously, with relatively low raw material costs and large production capacity. However, the reaction conditions are high temperature and high pressure, energy consumption is extremely high, equipment material requirements are high, catalyst costs are high and maintenance is complex, and acidic wastewater cannot be utilized.

[0010] II. Simple Recovery of Acidic Wastewater to Produce Ammonium Sulfide

[0011] (1) Simple bubbling absorption and intermittent reaction method: After simple stripping or stripping of acidic wastewater, crude H2S is directly passed into ammonia water for bubbling absorption. The pH value and temperature are manually controlled, and the product is discharged intermittently. This method has very low equipment investment and simple operation, but the system has poor airtightness, serious leakage of H2S and NH3, high safety and environmental risks, extremely low separation accuracy, high impurity content in the product, dark color, poor stability, and cannot achieve continuous production. The residual sulfide concentration in the tail gas and wastewater is high, which poses a serious secondary pollution problem.

[0012] (2) Single-tower low-pressure stripping and simple absorption method: Acidic wastewater is stripped at low pressure (≤0.2MPa) in a single tower to coarsely separate H2S and NH3. The gas phase is directly sent to the ammonia absorption tower to generate ammonium sulfide without deep purification treatment, and the product is directly concentrated. This method has a slightly better separation effect than the bubbling method, but the separation effect of H2S and NH3 is poor, cross-contamination is serious, the product purity is low, the energy consumption is still high, and the equipment corrosion problem has not been fundamentally solved.

[0013] III. High-Temperature Dual-Tower Pressurized Stripping Recovery Method (Current mainstream wastewater treatment process in the industry, not for direct preparation of ammonium sulfide)

[0014] High-concentration acidic wastewater undergoes high-temperature (150–180℃) double-tower or single-tower (0.5–0.8MPa) stripping treatment. The first tower removes H2S, and the second tower removes NH3 (or NH3 is removed in the middle section of the tower and H2S is removed at the top). H2S and NH3 are recovered and sent to subsequent processes for further treatment. The treated wastewater is discharged or reused after meeting standards. This method has a large wastewater treatment capacity, mature and reliable technology, and can be operated continuously. However, it requires huge equipment investment, has extremely high steam energy consumption, suffers from severe equipment corrosion under high temperature and pressure conditions, has high operation and maintenance costs, short service life, poor separation accuracy (ammonia water contains sulfur, resulting in low recovery value), and cannot achieve on-site resource recovery (the separated H2S and NH3 need to undergo a synthesis process, which is lengthy and costly). Furthermore, it does not have the function of directly producing high-purity ammonium sulfide and is essentially only a wastewater pretreatment process.

[0015] In summary, the existing technology has the following core technical defects:

[0016] (1) Traditional acid water treatment processes cannot adapt to the working conditions of hydrogenated acid water with high sulfur, high nitrogen, high chloride ions and complex impurities. During the treatment process, ammonium salt crystals such as ammonium chloride and ammonium hydrosulfide are easily generated, which frequently causes equipment pipeline blockage and pressure drop, making it impossible to achieve long-term stable operation.

[0017] (2) Traditional treatment processes mainly rely on conventional stripping and harmless incineration, which can only achieve the standard discharge of wastewater and cannot efficiently recover sulfur and ammonia resources. The ammonia water produced has low purity and high impurity content, and lacks market added value.

[0018] (3) Conventional processes are lengthy, require a lot of equipment, consume a lot of heating energy, and cannot adaptively adjust process parameters according to the fluctuation of nitrogen-sulfur ratio in acidic water. They also have poor water quality adaptability and insufficient operating stability.

[0019] Therefore, the present invention provides a system and process for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water, in order to solve the technical defects in the prior art. Summary of the Invention

[0020] The purpose of this invention is to provide a system for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water. By constructing a low-energy-consumption and low-operation-maintenance cost acidic water resource pretreatment system, high-precision separation of hydrogen sulfide and ammonia components in acidic wastewater is achieved. High-purity ammonium sulfide aqueous solution is directly synthesized from the native sulfur and ammonia components in the wastewater as raw materials, thereby solving the problems of high energy consumption, complex process, low resource utilization rate and insufficient product purity in existing acidic water treatment processes.

[0021] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0022] This invention relates to a system for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water, comprising, in sequence along the material flow direction: an acidic water buffer tank, a clay tank, a steam heater, an ammonium chloride crystallization washing tank, and an ammonium sulfide circulating absorption tower;

[0023] The outlet of the acidic water buffer tank is connected to the inlet of the acidic water feed pump, the outlet of the acidic water feed pump is connected to the inlet of the clay tank, the outlet of the clay tank is connected to the inlet of the steam heater, and the outlet of the steam heater is connected to the feed inlet in the middle of the ammonium chloride crystallization washing tank.

[0024] The top gas phase outlet of the ammonium chloride crystallization washing tank is connected to the inlet of the dry vacuum pump, and the outlet of the dry vacuum pump is connected to the lower gas inlet of the ammonium sulfide circulating absorption tower.

[0025] The ammonium chloride crystallization washing tank is provided with a first discharge branch and a second discharge branch at the bottom. The first discharge branch is connected to an ammonium chloride aqueous solution buffer tank, and the second discharge branch is connected to a low-concentration acidic water buffer tank.

[0026] The ammonium chloride aqueous solution buffer tank is equipped with an ammonium chloride aqueous solution drain pump at the bottom, and the low-concentration acidic water buffer tank is equipped with a low-concentration acidic water drain pump at the bottom.

[0027] The ammonium chloride crystallization washing tank is externally connected to a demineralized water supply pipeline and a nitrogen delivery pipeline. Both the demineralized water supply pipeline and the nitrogen delivery pipeline are connected to the interior of the ammonium chloride crystallization washing tank. The demineralized water supply pipeline is also branched to connect to the ammonium chloride aqueous solution buffer tank.

[0028] The ammonium chloride crystallization washing tank is equipped with a crystallization precipitation component, and the system is equipped with a differential pressure interlock automatic switching component, a temperature control component, a vacuum adjustment component, a concentration detection component, and a main control unit.

[0029] The clay tank is filled with clay adsorbent, and both the clay tank and the ammonium chloride crystallization washing tank are equipped with a pipeline valve group structure that can be installed in parallel and switched.

[0030] The bottom liquid phase outlet of the ammonium sulfide circulating absorption tower is connected to the inlet of the ammonium sulfide circulating external collection pump, and the outlet of the ammonium sulfide circulating external collection pump is connected to the inlet of the ammonium sulfide circulating cooler. The outlet of the ammonium sulfide circulating cooler is divided into two paths: one path is connected to the reflux liquid inlet at the top of the ammonium sulfide circulating absorption tower, and the other path is set as the product collection pipeline for industrial-grade ammonium sulfide aqueous solution.

[0031] The present invention is further configured such that the clay tank and the ammonium chloride crystallization washing tank are both arranged in parallel with a one-in-use-one-out-of-service configuration through a parallel switching pipeline valve group, and the two tanks are switched by valves to achieve alternating operation and offline cleaning.

[0032] The present invention is further configured such that the ammonium chloride crystallization washing tank is provided with crystallization plates or packing materials through an internal crystallization precipitation component for ammonium chloride crystals to adhere and precipitate;

[0033] The operating conditions of the ammonium chloride crystallization washing tank are: temperature 60-70℃, vacuum degree -0.07 to -0.09MPa; the automatic tank switching and salt dissolving cleaning operations are realized through the differential pressure interlock automatic switching component.

[0034] The present invention is further configured such that the dry vacuum pump is directly connected to the gas phase outlet at the top of the ammonium chloride crystallization washing tank, so as to stably maintain the negative pressure environment at the top of the ammonium chloride crystallization washing tank, and the system negative pressure fluctuation is controlled within ±0.005MPa;

[0035] The ammonium sulfide circulating cooler is connected in series in the outlet pipeline of the ammonium sulfide circulating external pump to control the temperature of the circulating absorbent, so that the temperature of the ammonium sulfide absorbent flowing through the cooler is stably maintained at 25-35℃.

[0036] The present invention is further configured such that the clay adsorbent filled inside the clay tank is used to adsorb and remove colloids, floating oil and macromolecular organic impurities contained in acidic water.

[0037] This invention also provides a process for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water, comprising the following steps:

[0038] S1. High-concentration acidic water is transported to an acidic water buffer tank to complete homogenization and pressure stabilization pretreatment;

[0039] S2. The pretreated acidic water is sent into the white clay tank, where the white clay adsorbent in the tank removes colloids, floating oil and large molecular organic impurities from the acidic water.

[0040] S3. The purified acidic water is fed into a steam heater. The temperature control component and concentration detection component collect the chloride ion content signal in real time and adjust the heating temperature accordingly. When the chloride ion content is too high, the steam heater outlet temperature is adjusted to 65-70℃. When the chloride ion content is too low, the reference temperature of 60℃ is maintained. The vacuum flash evaporation rate of the system is stably controlled at 8%-15% of the mass flow rate of the acidic water feed.

[0041] S4. The heated and temperature-adjusted acidic water is sent to the ammonium chloride crystallization washing tank, where flash evaporation is carried out under a vacuum low temperature environment of 60-70℃ and -0.07 to -0.09MPa, allowing ammonium chloride to precipitate statically through the internal crystallization components. The material at the bottom of the tank is processed by a dual-branch diversion method. The ammonium chloride crystals in the tank are dissolved using demineralized water. After being purged and stirred with nitrogen to aid dissolution, the solution is sent to the ammonium chloride aqueous solution buffer tank to obtain an industrial-grade ammonium chloride aqueous solution. The low-concentration acidic water is sent to the low-concentration acidic water buffer tank and then transported to the downstream processing steps.

[0042] S5. The ammonia and hydrogen sulfide mixed gas phase precipitated at the top of the ammonium chloride crystallization washing tank is stably extracted and transported by a dry vacuum pump; the system vacuum degree is adjusted in linkage with the nitrogen-sulfur molar ratio detection signal. When the nitrogen-sulfur molar ratio of the raw material is too high, the system vacuum degree is increased to -0.085 to -0.09 MPa, and when the nitrogen-sulfur molar ratio of the raw material is too low, it is decreased to -0.07 to -0.075 MPa, and the ammonia to hydrogen sulfide molar ratio in the gas phase is constantly controlled at 2.6 to 2.8:1.

[0043] S6. A mixture of ammonia and hydrogen sulfide with a constant ratio is fed into the ammonium sulfide circulating absorption tower, where it reacts countercurrently with the top spray absorption liquid to generate an ammonium sulfide aqueous solution. The bottom circulating liquid is pumped by the ammonium sulfide circulating external pump into the ammonium sulfide circulating cooler to maintain a constant temperature of 25-35°C. After temperature control, part of the liquid phase is returned to the top of the ammonium sulfide circulating absorption tower for continuous circulating spray reaction, while the other part is collected externally through the product collection pipeline, stably producing an industrial-grade high-concentration ammonium sulfide aqueous solution with a mass fraction of 8%-20%.

[0044] The present invention is further configured such that a temperature sensor and a chloride ion concentration detector are installed on the outlet pipe of the steam heater. Both the temperature sensor and the chloride ion concentration detector are electrically connected to the main control unit. The main control unit adjusts the heating power of the steam heater in conjunction with the chloride ion concentration detection feedback signal to achieve temperature control.

[0045] The present invention is further configured such that a vacuum degree regulating valve and a nitrogen-sulfur ratio detector are installed on the inlet pipe of the dry vacuum pump. The vacuum degree regulating valve and the nitrogen-sulfur ratio detector are both electrically connected to the main control unit. The main control unit adjusts the opening of the vacuum degree regulating valve according to the nitrogen-sulfur molar ratio detection signal to complete the system vacuum degree linkage regulation.

[0046] The present invention is further configured such that a temperature sensor and a flow regulating valve are installed on the outlet pipe of the ammonium sulfide circulating cooler. The temperature sensor and the flow regulating valve are electrically connected to the main control unit. The main control unit adjusts the opening of the flow regulating valve according to the liquid phase temperature feedback signal to stably control the temperature of the circulating spray liquid and the externally sourced product liquid to be in the range of 25-35℃.

[0047] The present invention has the following beneficial effects:

[0048] 1. This invention can adapt to complex and extreme water quality conditions, overcome the technical bottleneck that traditional systems cannot handle complex acidic water with high sulfur, high nitrogen, and high chlorine, effectively solve the problems of equipment salting and clogging under high chlorine conditions, and can achieve long-term continuous and stable operation. It is especially suitable for high-concentration and difficult-to-treat acidic water generated in working conditions such as tire oil hydrogenation.

[0049] 2. This invention constructs a dual-parameter coupled control system that controls temperature by chloride ion content and vacuum by nitrogen-sulfur molar ratio. It can adapt to fluctuating water quality conditions with different chloride ion contents and different nitrogen-sulfur molar ratios, and has a wide range of industrial applications and strong adaptability to working conditions.

[0050] 3. This invention, through differential pressure interlocking tank cutting, soluble salt extraction and gravity-flow separation structure, can simultaneously and stably produce industrial-grade ammonium chloride aqueous solution and ammonium sulfide aqueous solution with a mass fraction of 8% to 20%, realizing the resource utilization of all components of acidic wastewater and producing products with high added value.

[0051] 4. This invention eliminates the risk of salt blockage at the source through pre-treatment for impurity removal, precise control of temperature and pressure, and static crystallization desalination. It eliminates the need for frequent shutdowns for cleaning and significantly extends the continuous operation cycle of the system.

[0052] 5. This invention maintains a slightly excess ammonia state by constantly controlling the gas phase NH3 / H2S escaping molar ratio at 2.6 to 2.8:1, thereby eliminating the generation of ammonium hydrosulfide byproducts from the source; combined with the back-end low-temperature locking technology, the product concentration is stable, the purity is high, and there are no batch quality fluctuations.

[0053] 6. This invention adopts dual-tank automatic switching technology, dual-parameter adaptive control technology and fully enclosed negative pressure operation mode, which eliminates the risk of toxic gas leakage, is easy to operate and maintain, and has low energy consumption, and can fully meet the industrial needs of long-cycle continuous production in petrochemical plants. Attached Figure Description

[0054] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 A schematic diagram of a system for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from highly concentrated acidic water.

[0056] Figure 2 This is a process flow diagram of the present invention.

[0057] The attached diagram lists the components represented by each number as follows:

[0058] 1. Acidic water buffer tank; 2. Acidic water feed pump; 3. Clay tank; 4. Steam heater; 5. Ammonium chloride crystallization washing tank; 6. Vacuum pump; 7. Ammonium sulfide circulating absorption tower; 8. Ammonium sulfide circulating external pump; 9. Ammonium sulfide circulating cooler; 10. Low-concentration acidic water buffer tank; 11. Low-concentration acidic water discharge pump; 12. Ammonium chloride aqueous solution buffer tank; 13. Ammonium chloride aqueous solution discharge pump. Detailed Implementation

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Example 1, please refer to Figure 1 and Figure 2 This invention relates to a system for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water.

[0061] The sulfur-containing amino acid aqueous solution of a 50,000-ton / year tire oil hydrotreating unit has the following composition:

[0062] numerical values 31290 14473.17 474.5

[0063] After being homogenized and stabilized by acidic water buffer tank 1, acidic water is sent to kaolin tank 3 by acidic water feed pump 2. Kaolin tank 3 adopts a dual-tank operation mode with one tank in use and one in standby, and a single tank operating at low speed. The kaolin adsorbent filled in the tank removes organic impurities such as colloids and trace amounts of floating oil, eliminating the interference of impurities on the crystallization process and mass transfer process, and ensuring that the high-concentration components are released uniformly and stably.

[0064] Based on the chloride ion content, the steam heater 4 is stably controlled at 62℃, and the flash evaporation rate is controlled at 9% / h of the acidic water feed mass flow rate. This ensures that chloride ions are fully enriched, ammonium chloride crystallizes and precipitates in an orderly manner, avoids local salt blockage, and also prevents ammonia escape and gas phase ratio disorder caused by excessive temperature.

[0065] The material enters the ammonium chloride crystallization washing tank 5 evenly through the central inlet, maintaining a steady-state condition of 60℃ and -0.075MPa. The mixed gas at the top of the tank is collected and sent to the dry vacuum pump 6. The desalinated low-concentration acidic water in the tank flows by gravity into the low-concentration acidic water buffer tank 10 based on the liquid level difference. Under the condition of 5t / h feed, the gravity flow rate is stable at 4.2~4.5t / h, the external temperature is 58~60℃, and the load of the downstream water treatment unit is stable. The ammonium chloride crystallization washing tank 5 adopts a dual-tank parallel configuration, and the entire process is automatically switched through a 0.015MPa pressure differential interlock.

[0066] The system uses the total control unit and nitrogen-sulfur ratio detection signal to stably control the gas phase NH3 / H2S escaping molar ratio to 2.65-2.75:1, maintaining the optimal reaction atmosphere of slight ammonia excess and eliminating the generation of ammonium hydrosulfide byproducts from the source.

[0067] As the crystallization process continues, the ammonium chloride salt layer gradually accumulates on the crystallization plate or packing inside the tank, and the pressure difference inside the tank continuously increases. When the pressure difference reaches the interlocking threshold of 0.015 MPa, the pressure difference interlocking automatic switching component is triggered, and the system automatically switches the working state of the two tanks. The online operating tank switches to the standby salt dissolving mode, and the clean standby tank is immediately put into operation to achieve uninterrupted continuous production. After the switch, the crystallization tank is shut down and demineralized water is introduced into the sealed tank to dissolve the crystals. Combined with nitrogen closed purging and conveying, the high-purity ammonium chloride aqueous solution is sent to the ammonium chloride aqueous solution buffer tank 12 to complete the resource recovery.

[0068] This process adopts a zoned operation mode of "continuous gravity discharge of low-concentration water and intermittent pressure differential salt dissolution and salt collection". The two sets of operations do not interfere with each other and the operating conditions are stable. The high-purity ammonium chloride aqueous solution prepared by pressure differential salt dissolution is stored and sent out as a product. The low-concentration clean acidic water is sent into the downstream water treatment unit at constant temperature and constant flow to achieve closed-loop zero discharge of wastewater.

[0069] A constant-ratio ammonia-sulfur mixture is pressurized by a pre-installed dry vacuum pump 6 and then fed into the ammonium sulfide circulating absorption tower 7, with vacuum fluctuations controlled within ±0.005 MPa. The circulating liquid at the bottom of the tower is kept at a constant temperature of 28–30°C by the ammonium sulfide circulating cooler 9, which uses the low temperature to inhibit the decomposition of ammonium sulfide and the escape of components, thus stabilizing the gas-liquid absorption balance. The spray liquid circulates repeatedly to continuously produce qualified ammonium sulfide aqueous solution products.

[0070] In this embodiment, the system operated continuously and stably for 30 days at a capacity of 5t / h. There was no salt buildup, no blockage, no fluctuation in operating conditions, and no ammonium sulfide byproducts were generated. The system stably produced an industrial-grade ammonium sulfide aqueous solution with a mass fraction of 11% to 15%, and simultaneously produced a qualified industrial-grade ammonium chloride aqueous solution.

[0071] Example 2, please refer to Figure 1 and Figure 2 In this embodiment, a constant continuous feed of 10t / h is used to treat the extremely high concentration of acidic water generated during the tire oil hydrogenation process. The measured water quality indicators are: ammonia nitrogen 74590.00mg / L, chloride ion 86324mg / L, and sulfide 36910mg / L, which are under the harsh water quality conditions of ultra-high nitrogen, ultra-high sulfur, and ultra-high chloride.

[0072] High-concentration acidic water enters acidic water buffer tank 1 at a flow rate of 10t / h and at normal temperature and pressure for homogenization and pressure stabilization, balancing the fluctuations of ultra-high concentration components in the water body, and stably outputting 10t / h of homogenized acidic water at 25-30℃ and normal pressure.

[0073] After pressure stabilization, acidic water is fed into clay tank 3 at a rate of 10t / h, 25-30℃ and atmospheric pressure by acidic water feed pump 2. The dual-tank alternating operation mode is adopted to deeply remove colloids, heavy oil and macromolecular organic impurities from the water.

[0074] In response to the ultra-high chlorine water quality conditions under this working condition, the chlorine content linkage temperature control mechanism is activated. The outlet medium temperature of the steam heater 4 is kept constant at 68℃ to adapt to the high load condition of 10t / h. The vacuum flash evaporation rate is stably controlled to 13% / h of the acidic water feed mass flow rate to accelerate the supersaturated orderly crystallization and precipitation of chloride ions, and to prevent salt accumulation and caking blockage under ultra-high chlorine conditions.

[0075] After heat exchange, the acidic water is evenly distributed at 10t / h and 68℃ through the central feed inlet of ammonium chloride crystallization washing tank 5. The two tanks operate in a dual-use, standby, interlocked manner. The steady-state parameters inside the tanks are a temperature of 60℃ and a system vacuum of -0.085MPa, with vacuum fluctuations controlled within ±0.005MPa. The equipment adopts a structure with central feed, upper gas collection, and lower gravity flow. The ammonia-sulfur mixture is extracted by negative pressure at the top of the tank, and the tank is subjected to low-temperature vacuum and gentle flash evaporation to achieve uniform static crystallization and precipitation of ammonium chloride.

[0076] The desalinated low-concentration acidic water flows continuously by gravity due to the liquid level difference, with a stable flow rate of 8.4-8.7 t / h and a temperature of 57-59℃, and flows into the low-concentration acidic water buffer tank 10 by gravity.

[0077] As crystallization continues, the salt layer at the bottom of the tank accumulates and the system pressure difference gradually increases. When the pressure difference inside the tank reaches the interlock threshold of 0.015 MPa, the pressure difference interlock automatic switching component is triggered, and the system automatically completes the seamless switching between the two tanks. The offline crystallization tank is sealed and purged with room temperature demineralized water to dissolve the salt layer. Combined with nitrogen pressure stabilization purging at 0.1–0.15 MPa, the high-purity ammonium chloride aqueous solution is sealed and transported to the ammonium chloride aqueous solution buffer tank 12.

[0078] This operating condition adopts a dual-branch stable operation mode: the ammonium chloride aqueous solution branch is intermittently extracted after differential pressure tank switching, with the extracted liquid temperature at 54-58℃ and transported at normal pressure; the low-concentration acidic water branch is continuously delivered throughout the entire process, with a flow rate of 8.4-8.7t / h and a temperature of 57-59℃. The two branches do not interfere with each other and the operating conditions are stable.

[0079] The mixed gas at the top of the tank is drawn by a dry vacuum pump 6 under stable pressure at -0.085 MPa and 60℃, with stable negative pressure and no fluctuations. Through a nitrogen-sulfur ratio-linked pressure control mechanism, the total control unit and the nitrogen-sulfur ratio detection signal precisely control the gas phase NH3 / H2S escaping molar ratio to 2.70–2.80:1. The system maintains a low-speed, gentle flash evaporation of acidic water feed at a mass flow rate of 13% / h, with synchronous and uniform gas phase escaping.

[0080] A constant ratio of ammonia-sulfur mixed gas enters the ammonium sulfide circulating absorption tower 7, which operates at atmospheric pressure. The circulating liquid at the bottom of the tower is strictly temperature-controlled at 30-32°C by the ammonium sulfide circulating cooler 9. The low temperature is used to suppress the thermal decomposition reaction of high-concentration ammonium sulfide and lock in the gas-liquid absorption balance. Part of the cooled liquid is returned to the top of the tower for circulating spraying to ensure full gas-liquid contact reaction. The other part is continuously collected as finished product, stably producing an industrial-grade ammonium sulfide aqueous solution with a mass fraction of 16%-20%.

[0081] This embodiment operates continuously and stably for 30 days under harsh conditions of 10t / h ultra-high salinity. The system exhibits no salt buildup, no blockage, no operating fluctuations, and no excessive by-products. The dual-parameter adaptive system can accurately adapt to extreme water quality conditions of ultra-high nitrogen, ultra-high sulfur, and ultra-high chlorine, and can stably co-produce high-purity ammonium chloride aqueous solution and high-concentration ammonium sulfide aqueous solution with a mass fraction of 16% to 20% for a long period of time.

[0082] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0083] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A system for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water, characterized in that, The components, in sequence along the material flow direction, include: acidic water buffer tank (1), clay tank (3), steam heater (4), ammonium chloride crystallization washing tank (5), and ammonium sulfide circulating absorption tower (7). The outlet of the acidic water buffer tank (1) is connected to the inlet of the acidic water feed pump (2), the outlet of the acidic water feed pump (2) is connected to the inlet of the clay tank (3), the outlet of the clay tank (3) is connected to the inlet of the steam heater (4), and the outlet of the steam heater (4) is connected to the middle feed port of the ammonium chloride crystallization washing tank (5). The top gas phase outlet of the ammonium chloride crystallization washing tank (5) is connected to the inlet of the dry vacuum pump (6), and the outlet of the dry vacuum pump (6) is connected to the lower air inlet of the ammonium sulfide circulating absorption tower (7). The ammonium chloride crystallization washing tank (5) has a first discharge branch and a second discharge branch at the bottom. The first discharge branch is connected to the ammonium chloride aqueous solution buffer tank (12), and the second discharge branch is connected to the low concentration acid water buffer tank (10). The ammonium chloride aqueous solution buffer tank (12) is equipped with an ammonium chloride aqueous solution drain pump (13) at the bottom, and the low concentration acid water buffer tank (10) is equipped with a low concentration acid water drain pump (11) at the bottom. The ammonium chloride crystallization washing tank (5) is externally connected to a demineralized water supply pipeline and a nitrogen delivery pipeline. The demineralized water supply pipeline and the nitrogen delivery pipeline are both connected to the interior of the ammonium chloride crystallization washing tank (5). The demineralized water supply pipeline is also connected to the ammonium chloride aqueous solution buffer tank (12). The ammonium chloride crystallization washing tank (5) is equipped with a crystallization precipitation component, and the system is equipped with a differential pressure interlock automatic switching component, a temperature control component, a vacuum adjustment component, a concentration detection component and a main control unit; The white clay tank (3) is filled with white clay adsorbent. Both the white clay tank (3) and the ammonium chloride crystallization washing tank (5) are equipped with a pipeline valve group structure that can be installed in parallel and switched. The bottom liquid phase outlet of the ammonium sulfide circulating absorption tower (7) is connected to the inlet of the ammonium sulfide circulating external collection pump (8), and the outlet of the ammonium sulfide circulating external collection pump (8) is connected to the inlet of the ammonium sulfide circulating cooler (9). The outlet of the ammonium sulfide circulating cooler (9) is divided into two paths: one path flows back to the upper reflux liquid inlet of the ammonium sulfide circulating absorption tower (7), and the other path is set as the product collection pipeline for industrial-grade ammonium sulfide aqueous solution.

2. The system for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water according to claim 1, characterized in that, The clay tank (3) and ammonium chloride crystallization washing tank (5) are both arranged in parallel with one tank in use and one in standby by a parallel switching pipeline valve group. The two tanks are switched by valves to achieve alternating operation and offline cleaning.

3. The system for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water according to claim 1, characterized in that, The ammonium chloride crystallization washing tank (5) is equipped with crystallization plates or packing materials through internal crystallization precipitation components for ammonium chloride crystals to adhere and precipitate. The operating conditions of the ammonium chloride crystallization washing tank (5) are: temperature 60~70℃, vacuum degree -0.07~-0.09MPa; the automatic tank switching and salt dissolving cleaning operation are realized through the differential pressure interlock automatic switching component.

4. The system for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water according to claim 1, characterized in that, The dry vacuum pump (6) is directly connected to the gas phase outlet at the top of the ammonium chloride crystallization washing tank (5) to stably maintain the negative pressure environment at the top of the ammonium chloride crystallization washing tank (5), and the system negative pressure fluctuation is controlled within ±0.005MPa; The ammonium sulfide circulating cooler (9) is connected in series to the outlet pipeline of the ammonium sulfide circulating external pump (8) to regulate the temperature of the circulating absorbent liquid, so that the temperature of the ammonium sulfide absorbent liquid flowing through the cooler is stably maintained at 25-35℃.

5. The system for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water according to claim 1, characterized in that, The clay adsorbent filled inside the clay tank (3) is used to adsorb and remove colloids, floating oil and macromolecular organic impurities contained in acidic water.

6. A process for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water, characterized in that, The system described in any one of claims 1 to 5 is implemented by comprising the following steps: S1. High-concentration acidic water is transported to acidic water buffer tank (1) to complete homogenization and pressure stabilization pretreatment; S2. The pretreated acidic water is sent into the white clay tank (3) to remove colloids, floating oil and macromolecular organic impurities from the acidic water using the white clay adsorbent in the tank. S3. The acidic water after impurity removal is fed into the steam heater (4). The temperature control component and concentration detection component collect the chloride ion content signal in real time and adjust the heating temperature accordingly. When the chloride ion content is too high, the discharge temperature of the steam heater (4) is adjusted to 65-70℃. When the chloride ion content is too low, the reference temperature of 60℃ is maintained. The vacuum flash evaporation rate of the system is stably controlled to 8%-15% of the mass flow rate of the acidic water feed. S4. The heated and temperature-adjusted acidic water is sent to the ammonium chloride crystallization washing tank (5). Flash evaporation is carried out in a vacuum low temperature environment of 60-70℃ and -0.07--0.09MPa, so that ammonium chloride is statically crystallized and precipitated through the internal crystallization components. The bottom material of the tank is processed by dual-branch diversion. The ammonium chloride crystals in the tank are dissolved by demineralized water. After nitrogen is used to purge and stir in the tank to aid dissolution, it is sent to the ammonium chloride aqueous solution buffer tank (12) to obtain industrial grade ammonium chloride aqueous solution. The low concentration acidic water is sent to the low concentration acidic water buffer tank (10) and transported to the downstream processing step. S5. The ammonia and hydrogen sulfide mixed gas phase precipitated at the top of the ammonium chloride crystallization washing tank (5) is stably extracted and transported by a dry vacuum pump (6); the system vacuum degree is adjusted in linkage with the nitrogen-sulfur molar ratio detection signal. When the nitrogen-sulfur molar ratio of the raw material is too high, the system vacuum degree is increased to -0.085 to -0.09 MPa, and when the nitrogen-sulfur molar ratio of the raw material is too low, it is decreased to -0.07 to -0.075 MPa, and the ammonia and hydrogen sulfide escaping molar ratio in the gas phase is constantly controlled to be 2.6 to 2.8:1; S6. A mixture of ammonia and hydrogen sulfide with a constant ratio is fed into the ammonium sulfide circulating absorption tower (7) and reacts with the top spray absorption liquid to generate an ammonium sulfide aqueous solution. The bottom circulating liquid is sent to the ammonium sulfide circulating cooler (9) by the ammonium sulfide circulating external collection pump (8) and kept at a constant temperature of 25-35°C. After temperature control, part of the liquid phase flows back to the top of the ammonium sulfide circulating absorption tower (7) for continuous circulating spray reaction, and the other part is collected externally through the product collection pipeline to stably obtain an industrial-grade high-concentration ammonium sulfide aqueous solution with a mass fraction of 8%-20%.

7. The process for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water according to claim 6, characterized in that, A temperature sensor and a chloride ion concentration detector are installed on the outlet pipe of the steam heater (4). The temperature sensor and the chloride ion concentration detector are electrically connected to the main control unit. The main control unit adjusts the heating power of the steam heater (4) in conjunction with the chloride ion concentration detection feedback signal to achieve temperature control.

8. The process for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water according to claim 6, characterized in that, The dry vacuum pump (6) is equipped with a vacuum regulating valve and a nitrogen-sulfur ratio detector on the inlet pipe. The vacuum regulating valve and the nitrogen-sulfur ratio detector are electrically connected to the main control unit. The main control unit adjusts the opening of the vacuum regulating valve according to the nitrogen-sulfur molar ratio detection signal to complete the system vacuum linkage adjustment.

9. The process for preparing industrial-grade high-concentration ammonium sulfide aqueous solution from high-concentration acidic water according to claim 6, characterized in that, A temperature sensor and a flow regulating valve are installed on the outlet pipe of the ammonium sulfide circulating cooler (9). The temperature sensor and the flow regulating valve are electrically connected to the main control unit. The main control unit adjusts the opening of the flow regulating valve according to the liquid phase temperature feedback signal to stably control the temperature of the circulating spray liquid and the externally sourced product liquid to be in the range of 25-35℃.

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