An efficient ammonium sulfate saturator system based on mother liquor loop circulation strengthening

Abstract

The application discloses a kind of based on mother liquor circulating flow reinforcement high-efficiency ammonium sulfate saturator system, including saturator main body, mother liquor circulating flow system and spraying device;The inside of the saturator main body is divided into spray zone and crystallization zone from top to bottom along the axial direction, the inlet of the mother liquor circulating flow system is communicated with the bottom of crystallization zone, and the outlet is connected with the spraying device at the top of spray zone, and the spraying device atomizes and evenly sprays mother liquor conveyed by the mother liquor circulating flow system.The application has the advantages compared with prior art: provide a kind of based on mother reinforcement high-efficiency ammonium sulfate saturator system for realizing the dynamic regulation and reinforcement of crystallization process.

Description

Technical Field

[0001] This invention relates to the field of ammonium sulfate production equipment technology, specifically to a high-efficiency ammonium sulfate saturator system based on mother-enhanced technology. Background Technology

[0002] Ammonium sulfate saturators are core equipment in industries such as coking and fertilizer production, used to recover ammonia-containing waste gas and produce ammonium sulfate. Traditional saturator processes rely on a counter-current reaction between ammonia-containing waste gas and circulating mother liquor within the saturator. The resulting ammonium sulfate solution, after reaching supersaturation, precipitates crystals in the bottom crystallization zone.

[0003] However, existing technologies have revealed significant drawbacks during long-term operation: First, traditional saturators mostly employ single-chamber or double-chamber structures, with mixing mechanisms primarily relying on simple stirring or natural convection, leading to uneven mixing of the mother liquor and large fluctuations in supersaturation distribution. This local concentration gradient easily triggers the formation of a large number of fine crystals, while crystal growth is slow in low supersaturation regions, resulting in a small average particle size (typically only 0.3-0.5 mm) and uneven particle size distribution, with poor crystal integrity.

[0004] Secondly, the residence time of crystals in the crystallization zone is insufficient (usually only 2-4 hours), which makes it difficult to meet the requirements of the ideal growth cycle and limits crystal growth. The existing mother liquor circulation system design has limitations, with a narrow flow adjustment range and the pipeline layout is prone to dead corners, resulting in low mass transfer efficiency and limited ammonia absorption rate per unit volume of mother liquor.

[0005] Furthermore, due to the lack of precise temperature and acidity control, fluctuations in mother liquor parameters can easily lead to a shortened crystallization induction time and a decrease in product purity.

[0006] The above problems together cause the inner walls of equipment and pipes to be easily blocked by local crystallization during the production process, requiring frequent shutdowns for cleaning (the cycle is usually 7-15 days), which seriously restricts the continuity of production, product quality and overall energy efficiency.

[0007] Therefore, developing a high-efficiency ammonium sulfate saturator system that can enhance mother liquor mixing, optimize crystallization kinetics, and achieve long-term stable operation has become a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the above-mentioned technical defects and provide a high-efficiency ammonium sulfate saturator system based on mother strengthening to achieve dynamic control and enhancement of the crystallization process.

[0009] To solve the above-mentioned technical problems, the technical solution provided by the present invention is: a high-efficiency ammonium sulfate saturator system based on mother liquor circulation enhancement, comprising a saturator body, a mother liquor circulation system and a spraying device; The interior of the saturator body is divided into a spray zone and a crystallization zone along the axial direction from top to bottom. The inlet of the mother liquor circulation system is connected to the bottom of the crystallization zone, and the outlet is connected to the spraying device at the top of the spray zone. The spraying device atomizes and sprays the mother liquor delivered by the mother liquor circulation system evenly.

[0010] Preferably, a temperature control unit and an impurity separation unit are also connected inside the saturator body; The impurity separation unit is located near the bottom of the crystallization zone to intercept large particles of impurities and separate fine crystals. The temperature control unit controls the temperature of the mother liquor inside the saturator body to 50~55℃.

[0011] Preferably, the mother liquor circulation system includes a main circulation pump and a frequency converter; The inlet of the main circulation pump is connected to the conical collection tank at the bottom of the crystallization zone through a pipe, and the outlet extends to the top of the spray zone through a circulation pipe and is connected to the annular mother liquor distribution pipe of the spraying device. The frequency converter is electrically connected to the main circulation pump and is used to adjust the circulation flow rate of the mother liquor to control the supersaturation of the crystallization zone.

[0012] Preferably, the frequency converter controls the flow rate of the main circulation pump to be 30-100 m³ / h.

[0013] Preferably, the crystallization zone is provided with a guide tube and an annular baffle. The guide tube is located at the center of the crystallization zone, and the annular baffle is located between the guide tube and the inner wall of the saturator, forming a crystal slurry circulation channel with external circulation rising and internal circulation falling. The average residence time of the crystal in the crystallization zone is 6-8 hours.

[0014] Preferably, the spraying device includes an annular mother liquor distribution pipe, several branch pipes evenly distributed on the annular mother liquor distribution pipe, and a fan-shaped atomizing nozzle installed at the end of the branch pipe. The branch pipe and the annular mother liquor distribution pipe are detachably connected by a flange. The spray angle of the fan-shaped atomizing nozzle is 60~90°, the spray coverage is ≥95%, and the droplet unevenness is <10%.

[0015] Preferably, the impurity separation unit includes a filter screen and an overflow trough located at the bottom of the crystallization zone; The filter screen intercepts large particles of impurities, and the overflow tank is connected to the mother liquor circulation pump to return the clarified mother liquor to the spraying area.

[0016] The advantages of this invention compared to the prior art are: Significantly improved crystal quality: The optimized crystallization environment increases the average diameter of ammonium sulfate crystals from 0.3-0.5 mm to 0.8-1.2 mm, improves crystal integrity (characterized by XRD) to over 90%, and achieves a product purity of over 99.5%, meeting the quality standards for high-end fertilizers and industrial-grade ammonium sulfate.

[0017] Production efficiency is comprehensively optimized: the enhanced mass transfer process shortens the crystallization cycle from 8-10 hours to 4-6 hours, an increase of 40-50% compared to traditional systems; the improved mother liquor circulation efficiency extends the continuous operation cycle of the system to 30-45 days, and reduces the frequency of shutdown cleaning by more than 60%.

[0018] Energy consumption and cost reduction: Variable frequency circulating pumps and optimized flow field design reduce unit product energy consumption from 0.6 kW·h / kg to 0.45-0.5 kW·h / kg; reducing maintenance costs caused by equipment blockage.

[0019] Enhanced operational stability: Supersaturation control accuracy improved to ±0.05, temperature fluctuation controlled within ±0.5℃, system operating parameter variation coefficient reduced from 8-12% to 3-5%, and product quality batch stability significantly improved. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a high-efficiency ammonium sulfate saturator system based on mother liquor circulation enhancement.

[0021] Figure 2 This is a structural block diagram of the mother liquor circulation system. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings.

[0023] Combined with appendix Figure 1-2 As shown, this invention aims to solve the technical bottlenecks of low crystallization efficiency and unstable crystal quality in existing ammonium sulfate saturator systems. Through an innovative design of the mother liquor circulation system, it achieves dynamic control and enhancement of the crystallization process. Specific objectives include: increasing the average particle size of ammonium sulfate crystals to 0.8-1.2 mm and reducing the particle size distribution variation coefficient to below 15%; optimizing mass transfer efficiency to increase the ammonia absorption rate per unit volume of mother liquor to 1.8-2.2 kg / (m·h); reducing equipment blockage frequency and extending the continuous operation cycle to over 30 days; and simultaneously reducing system energy consumption by 10-15%, achieving a synergistic improvement in production efficiency and product quality.

[0024] The saturator system of this invention includes: a saturator body, a mother liquor circulation system, a novel spraying device, a temperature control unit, and an impurity separation unit. The saturator body adopts a vertical cylindrical structure, internally divided axially into a spray zone (upper part, accounting for 40% of the height) and a crystallization zone (lower part, accounting for 60% of the height). The two zones are separated and directionally flowed by a guide plate. The mother liquor circulation system, as the core component, includes a main circulation pump (flow rate adjustable range 30-100 m³ / h), corrosion-resistant circulation pipes (made of 316L stainless steel), and an intelligent diversion device. Its inlet end is connected to a conical collection tank at the bottom of the crystallization zone, and its outlet end is connected to the top of the spray zone and the impurity separation unit via a three-way valve. The novel spraying device is installed at the top of the spray zone and is coaxially arranged with the ammonia-containing waste gas inlet pipe. The temperature control unit achieves ±0.5℃ precision control of the mother liquor temperature through a jacketed heat exchanger. The impurity separation unit integrates a filter screen (0.2mm pore size) and a cyclone separator to intercept large particles of impurities and separate fine crystals.

[0025] in: The working principle of the mother liquor circulation system is "bottom extraction and top spraying, with enhanced circulation": The main circulation pump extracts mother liquor containing crystals (solid content 20-30%) from the bottom of the crystallization zone, and transports it to the top of the spray zone through the circulation pipeline. There, it is mixed online with newly added 98% concentrated sulfuric acid solution (the addition amount is controlled according to n(HSO):n(NH) = 1.05:1) before entering the new spraying device. This device uses a ring-shaped mother liquor distribution pipe (diameter 0.8 times the inner diameter of the saturator), with 12-16 branch pipes evenly distributed along the circumference. Each branch pipe is equipped with a fan-shaped nozzle (spray angle 75°, atomized particle size 80-120μm), allowing the mixed mother liquor to form a uniform liquid film in the spray zone, ensuring full contact with the rising ammonia-containing waste gas (flow velocity 1.2-1.5 m / s). The main circulation pump speed is adjusted by a frequency converter to achieve stepless adjustment of the circulation flow rate from 30 to 100 m³ / h. Combined with the temperature control unit, the mother liquor temperature is maintained at 50-55℃, so that the supersaturation is stably controlled within the range of 1.2-1.5, providing the optimal kinetic environment for crystal growth.

[0026] The performance parameters are compared in Table 1: Table 1 Comparison of Performance Parameters ; The high-efficiency circulating pump adopts a double impeller design, with a head of 30-50 m and a flow fluctuation rate of <2%; the branch pipe and the ring pipe of the new spray device are connected by flanges, which is convenient for disassembly and cleaning; the nozzle material is 316L, which improves wear resistance by 3 times; the diameter of the crystallization zone guide tube is 0.4 times the inner diameter of the saturator, forming a "external circulation rising and internal circulation descending" flow field with the bottom baffle, effectively extending the crystal growth cycle.

[0027] In the specific implementation of this invention, during the installation of the saturator body, the verticality deviation must be calibrated with a level to ≤0.5° / m. The bottom is fixed to the concrete foundation with expansion bolts, and the joints are sealed with epoxy resin. The mother liquor circulation pipeline adopts a "top-in, bottom-out" path, with a main pipeline diameter of DN200 and branch pipelines of DN100. The spacing between pipeline supports is ≤2m, and flexible joints are installed at bends to absorb vibration. When connecting the pump body to the control unit, pressure gauges (range 0-1.0MPa) and check valves must be installed at the inlet and outlet of the main circulation pump, and the cable wiring must meet the IP65 protection level. Regarding sealing requirements, PTFE gaskets are used for flange connections, and threaded interfaces are wrapped with ≥3 turns of PTFE tape. After system assembly, a water pressure test at 1.2 times the working pressure is required, with a pressure holding time of 30 minutes without leakage. Safety precautions include: using specialized lifting tools when hoisting the saturator body, with a lifting angle ≤60°; grounding resistance of electrical equipment ≤4Ω; and using argon arc welding for pipeline welding, with a weld flaw detection pass rate of 100%.

[0028] The key process parameters and control objectives of this system are shown in Table 2. Table 2 ; The parameter control is achieved through a PLC system for fully automatic adjustment, which collects data every 5 seconds. In case of abnormality, it triggers an audible and visual alarm and automatically switches to the backup circuit.

[0029] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0030] Working principle of the invention: In the ammonia-containing waste gas pretreatment and preheating stage, the ammonia-containing waste gas needs to be passed into the saturator. Before starting the mother liquor circulation, the pump lubricating oil level and inlet / outlet valve status need to be checked. After a brief test run without abnormalities, the flow rate is gradually increased to 50 m³ / h to establish initial circulation. Sulfuric acid solution is added at a rate of 1.2-1.5 m³ / h, linked to the high-level tank level gauge and flow meter, to ensure that the mother liquor acidity is stable within the set range. In the ammonia absorption and crystallization stage, the ammonia-containing waste gas enters tangentially from the bottom of the saturator and comes into countercurrent contact with the sprayed mother liquor. The reaction temperature is maintained at 52±1℃ by the jacketed hot water, and the crystal slurry density in the crystallization zone is controlled at 1.25-1.30 g / cm³. Crystal separation is performed using a horizontal spiral centrifuge with a separation factor ≥3000 and a filter cake moisture content ≤3%. System cleaning and maintenance require monthly acid washing using 5% dilute sulfuric acid for 2 hours, and a full water wash every quarter. The nozzles are disassembled to check for blockages, ensuring that the spray coverage rate is maintained above 95%.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A high-efficiency ammonium sulfate saturator system based on mother liquor circulation enhancement, characterized in that: Includes the saturator body, mother liquor circulation system, and spraying device; The interior of the saturator body is divided into a spray zone and a crystallization zone along the axial direction from top to bottom. The inlet of the mother liquor circulation system is connected to the bottom of the crystallization zone, and the outlet is connected to the spraying device at the top of the spray zone. The spraying device atomizes and sprays the mother liquor delivered by the mother liquor circulation system evenly.

2. The high-efficiency ammonium sulfate saturator system based on mother liquor circulation enhancement according to claim 1, characterized in that: The saturator body is also equipped with a temperature control unit and an impurity separation unit; The impurity separation unit is located near the bottom of the crystallization zone to intercept large particles of impurities and separate fine crystals. The temperature control unit controls the temperature of the mother liquor inside the saturator body to 50~55℃.

3. The high-efficiency ammonium sulfate saturator system based on mother liquor circulation enhancement according to claim 2, characterized in that: The mother liquor circulation system includes a main circulation pump and a frequency converter; The inlet of the main circulation pump is connected to the conical collection tank at the bottom of the crystallization zone through a pipe, and the outlet extends to the top of the spray zone through a circulation pipe and is connected to the annular mother liquor distribution pipe of the spraying device. The frequency converter is electrically connected to the main circulation pump and is used to adjust the circulation flow rate of the mother liquor to control the supersaturation of the crystallization zone.

4. The high-efficiency ammonium sulfate saturator system based on mother liquor circulation enhancement according to claim 3, characterized in that: The frequency converter controls the flow rate of the main circulation pump to be between 30-100 m³ / h.

5. The high-efficiency ammonium sulfate saturator system based on mother liquor circulation enhancement according to claim 1, characterized in that: The crystallization zone is equipped with a guide tube and an annular baffle. The guide tube is located at the center of the crystallization zone, and the annular baffle is located between the guide tube and the inner wall of the saturator, forming a crystal slurry circulation channel with external circulation rising and internal circulation falling. The average residence time of the crystal in the crystallization zone is 6-8 hours.

6. The high-efficiency ammonium sulfate saturator system based on mother liquor circulation enhancement according to claim 2, characterized in that: The spraying device includes an annular mother liquor distribution pipe, several branch pipes evenly distributed on the annular mother liquor distribution pipe, and fan-shaped atomizing nozzles installed at the ends of the branch pipes. The branch pipes are detachably connected to the annular mother liquor distribution pipe by flanges. The spray angle of the fan-shaped atomizing nozzles is 60~90°, the spray coverage is ≥95%, and the droplet unevenness is <10%.

7. The high-efficiency ammonium sulfate saturator system based on mother liquor circulation enhancement according to claim 3, characterized in that: The impurity separation unit includes a filter screen and an overflow tank located at the bottom of the crystallization zone; The filter screen intercepts large particles of impurities, and the overflow tank is connected to the mother liquor circulation pump to return the clarified mother liquor to the spraying area.

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