Mother liquor level automatic detection and supplement subsystem in coked ammonium sulfate system

Abstract

The invention discloses an automatic mother liquor level detection and supplement subsystem in a coked ammonium sulfate system, which relates to the technical field of ammonium sulfate production systems and is technically characterized by comprising a radar liquid level meter mounted above a full-flow tank to measure the liquid level; the steam heater uses water vapor as a heat source to heat nitrogen or dry compressed air to 40-80 DEG C; the anti-frosting protection nozzle is of an angle-adjustable rotary type, a protection film can be formed on the surface of the radar liquid level meter probe, and the hot anti-frosting protection gas conveying pipe conveys heating gas for the radar liquid level meter probe. A saturator mother liquor operation control valve and a mother liquor circulation operation control valve control on-off of mother liquor; the anti-freezing and anti-crystallization blocking circulating pipe is prevented from being frozen and blocked by mother liquor; spraying the mother liquor to a French spray saturator by a spray absorption nozzle; the replenisher flowmeter measures the flow, and the replenisher pump provides power; the device has the functions of liquid level height automatic detection and supplement, radar liquid level frosting prevention in winter and acid gas corrosion prevention.

Description

Technical Field

[0001] This invention relates to the field of ammonium sulfate production system technology, and in particular to an automatic detection and replenishment subsystem for mother liquor level in a coking ammonium sulfate system. Background Technology

[0002] The French-style spray saturator is a coke oven gas ammonia purification device introduced from France in the late 20th century. Coke oven gas is produced by heating raw coal to 1000±50℃ for 16-96 hours in the absence of air. After passing through a condensing blower system and a desulfurization system, this gas enters the two annular absorption chambers at the top of the French-style spray saturator, where it comes into countercurrent contact with the mother liquor pumped by the large circulating mother liquor pump, resulting in mist absorption. Simultaneously, a small mother liquor pump continuously draws mother liquor from the full-flow tank to the rear absorption chamber of the saturator, acting as a gatekeeper for ammonia absorption in the coke oven gas. When the liquid level in the saturator reaches the full-flow pipe, it continuously overflows through the central pipe into the full-flow tank, forming a closed, continuous process flow.

[0003] The gas temperature entering the saturator is 28-38℃. To ensure efficient absorption of ammonia from the gas within the saturator, the circulating mother liquor temperature needs to be heated to 45-55℃. At this temperature, the purified gas leaving the saturator also rises to 45-55℃, resulting in a large amount of saturated water being carried away by the gas. Simultaneously, the mother liquor absorbs ammonia from the gas to form ammonium sulfate crystals. This reaction process reduces the volume of the product, and the ammonium sulfate crystals are extracted after saturation, further reducing the circulating mother liquor volume. To ensure continuous and stable production of the saturator system, the circulating mother liquor level needs to be maintained within a reasonable range, specifically, the full-flow tank level should be controlled between 1 / 5 and 4 / 5.

[0004] Currently, the mother liquor replenishment system in the ammonium sulfate section of the coking plant is operated manually, which is complex and poses safety hazards. The specific operating procedure is as follows: first, the bottom valve of the full-flow tank is closed 50-70%, then the outlet valve of the mother liquor tank is opened. Then, the operator observes the liquid level in the mother liquor tank from a height of 3.5-6 meters above the full-flow tank, observing it while observing the acid mist. When the level reaches 80-90%, the operator returns to the ground and closes the outlet valve of the mother liquor tank. Finally, the outlet valve of the full-flow tank is fully opened. This operation needs to be repeated more than 10 times a day, 24 hours a day. Incidents such as backflow from the full-flow tank, cavitation of the small mother liquor pump, and abnormal air intake flow frequently occur. Furthermore, sulfuric acid mist overflows from above the full-flow tank, posing significant risks to the production, safety, and occupational health of the ammonium sulfate system.

[0005] Although Utility Technology 202322791174 discloses an automatic liquid replenishment system, this process suffers from problems such as pipe blockage in northern regions during winter, process short circuits caused by mother liquor replenishing to full flow tanks, pipe blockage due to ammonium sulfate crystallization, frost formation on level detection probes in winter, and acid gas corrosion, making it difficult to apply in actual production. Therefore, developing a process that can solve the above problems is a key issue in the fields of production and process engineering. Summary of the Invention

[0006] In order to solve at least one of the above-mentioned technical problems, the present invention aims to provide an automatic detection and replenishment subsystem for mother liquor level in a coking ammonium sulfate system, which has the functions of automatic detection and replenishment of liquid level, anti-frost in winter by radar level detection, and anti-corrosion by acid gas.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An automatic mother liquor level detection and replenishment subsystem in a coking ammonium sulfate system includes:

[0009] Radar level gauges are used to measure the liquid level height in a full-flow tank.

[0010] A steam heater that heats nitrogen or dried compressed air;

[0011] Anti-frost protection nozzles form an insulating protective film on the surface of the radar level gauge probe;

[0012] The heat-resistant anti-frost protection gas delivery pipe delivers heated gas to the anti-frost protection nozzle.

[0013] The mother liquor inlet control valve controls the flow of mother liquor into the saturator.

[0014] The mother liquor circulation control valve controls the on / off state of the mother liquor circulation process;

[0015] Antifreeze and anti-crystallization circulation pipe, used for mother liquor circulation to prevent freezing and crystallization blockage;

[0016] Spray absorption nozzles spray the mother liquor into the French spray saturator;

[0017] The replenishment liquid flow meter measures the flow rate of the replenishment mother liquor;

[0018] The replenishment pump provides the power for transporting the mother liquor;

[0019] Warm water for rinsing is used to rinse pipes and equipment;

[0020] The remote control valve for warm water controls the flow of warm water into the system.

[0021] Mother liquor and warm water replenishment and circulation pipelines, mother liquor and warm water circulation and transportation channels;

[0022] The mother liquor tank outlet control valve controls the outflow of mother liquor from the mother liquor tank outlet;

[0023] Drain control valve, used for system venting;

[0024] The replenishment pump inlet control valve controls the entry of mother liquor into the replenishment pump inlet;

[0025] Mother liquor storage tank, for storing mother liquor;

[0026] French spray saturator, a device for absorbing ammonia by contacting mother liquor with coal gas;

[0027] A full-flow tank receives and stores the mother liquor, maintaining a certain liquid level.

[0028] The radar level gauge is installed above the full flow tank; the steam heater heats 0.05-1.0 MPa nitrogen or dried compressed air to 40-80°C using water vapor as a heat source, and delivers it to the anti-frost protection nozzle through the thermal anti-frost protection gas delivery pipe, forming a continuous and stable isolation protective film on the surface of the radar level gauge probe.

[0029] Confirm that the venting control valve and the warm water remote control valve are in the closed state; open the mother liquor tank outlet control valve, the replenishment pump inlet control valve, and the mother liquor circulation operation control valve; start the replenishment pump to form a closed-loop process cycle.

[0030] Preferably, the anti-frost protection nozzle is a rotary nozzle with an adjustable spray angle, and its spray direction forms a 5°-30° angle with the surface of the radar level gauge probe.

[0031] Preferably, the outer layer of the heat-resistant anti-frost protective gas delivery pipe is wrapped with a heat-insulating sleeve, and the heat-insulating sleeve is made of aluminum silicate fiber or aerogel felt.

[0032] Preferably, the mother liquor circulation control valve is a shut-off valve driven by a pneumatic diaphragm actuator, with an opening and closing time of ≤3 seconds, and is equipped with a valve position feedback sensor.

[0033] Preferably, the French-style spray saturator is divided into upper and lower spray zones, each spray zone is independently equipped with a spray absorption nozzle, and the nozzle orifice diameter is 1.5-3.0mm.

[0034] Preferably, the mother liquor storage tank is equipped with a liquid level lower limit alarm device. When the liquid level is lower than the set value, the replenishment pump is triggered to start automatically and open the control valve at the outlet of the mother liquor tank until the liquid level is restored to a safe range.

[0035] Preferably, the warm water pipe for rinsing is connected to the mother liquor circulation pipe via a three-way valve, which is an electric regulating valve that can automatically switch the flow path of warm water or mother liquor according to the rinsing mode.

[0036] Preferably, the top of the full-flow tank is provided with a vent valve, and the vent valve opens at a pressure of 0.02-0.05 MPa to balance the pressure inside the tank and prevent the mother liquor from overflowing.

[0037] The present invention has the following beneficial effects:

[0038] I. Automatic Liquid Level Detection and Precise Replenishment to Ensure Stable System Operation: This system monitors the liquid level in the full-flow tank in real time using a radar level gauge. Combined with the coordinated control of the mother liquor inlet valve, mother liquor circulation valve, and replenishment pump, it achieves automated closed-loop management of mother liquor replenishment. Compared to traditional manual operation, which requires frequent climbing of the full-flow tank (more than 10 times per day) and carries risks such as backflow and pump cavitation, this system can precisely control the liquid level within a safe range of 1 / 5 to 4 / 5, avoiding process short circuits or crystallization blockages caused by liquid level fluctuations. For example, the lower limit alarm device installed in the mother liquor storage tank automatically triggers the replenishment pump when the liquid level is too low, ensuring a stable circulating mother liquor volume, thereby maintaining the ammonia absorption efficiency in the French spray saturator and improving the crystallization quality of ammonium sulfate products.

[0039] II. Anti-Frost Protection for Radar Level Gauges in Winter, Ensuring Detection Accuracy: Addressing the issue of frost formation on radar level gauge probes due to low temperatures in northern winters, this system innovatively employs a combination design of a steam heater and an anti-frost protection nozzle. The steam heater heats nitrogen or dry compressed air (0.05-1.0 MPa) to 40-80°C, which is then delivered to the nozzle via a thermal anti-frost protection gas delivery pipe. The rotating anti-frost protection nozzle (spray angle 5°-30°) forms a continuous and stable gas isolation film on the probe surface, effectively preventing water vapor condensation. Furthermore, the thermal anti-frost protection gas delivery pipe is wrapped with an aluminum silicate fiber or aerogel felt insulation sleeve to reduce heat loss and ensure the gas remains at a high temperature upon reaching the nozzle. This design completely solves the problem of detection failure caused by frost formation in traditional level gauges at low temperatures, guaranteeing uninterrupted level monitoring throughout the year.

[0040] III. Acid Gas Corrosion Prevention and Pipeline Freezing and Blockage Prevention, Extending Equipment Life: This system employs multiple protection mechanisms to address the highly corrosive environment of ammonium sulfate production: Material Selection: The mother liquor and warm water replenishment and circulation pipelines are made of acid corrosion-resistant alloy materials, reducing the erosion of pipe walls by ammonium sulfate crystals; Freezing and Crystallization Blockage Prevention Circulation Pipes: Through optimized pipeline layout and insulation design, combined with the linkage of three-way valves between the flushing warm water pipeline and the mother liquor circulation pipeline, warm water flushing can be automatically switched when the system is shut down, preventing residual mother liquor crystallization blockage; Vent Valve Design: A vent valve with an opening pressure of 0.02-0.05MPa is installed at the top of the full-flow tank, balancing the pressure inside the tank while preventing sulfuric acid mist from overflowing, reducing health hazards to operators. These measures significantly reduce equipment failure rates, extend the service life of key components such as radar level gauges and valves, and lower maintenance costs.

[0041] IV. High-efficiency ammonia absorption and staged spraying to increase ammonium sulfate production: The French-style spray saturator is divided into upper and lower spray zones, each independently equipped with spray absorption nozzles with an orifice diameter of 1.5-3.0 mm, achieving staged countercurrent contact between the mother liquor and the coal gas: Upper spray zone: The mother liquor temperature is higher (45-55℃), mainly absorbing most of the ammonia in the coal gas; Lower spray zone: The mother liquor temperature is slightly lower, further absorbing residual ammonia and promoting the crystallization of ammonium sulfate. This design increases ammonia absorption efficiency by more than 15%, while optimizing the nozzle orifice diameter ensures uniform atomization of the mother liquor, avoiding the crystallization agglomeration problem caused by local over-concentration, ultimately improving the purity and yield of ammonium sulfate products.

[0042] V. Rapid Response Valves and Closed-Loop Circulation for Optimized Process Control: This system utilizes pneumatic diaphragm actuators to drive the mother liquor circulation control valves (opening and closing time ≤ 3 seconds), equipped with valve position feedback sensors to achieve rapid and precise switching of the mother liquor circulation process. For example, during replenishment, the system can monitor the replenishment flow meter data in real time and dynamically adjust the opening of the mother liquor control valve in the saturator to prevent over- or under-replenishment of mother liquor. The closed-loop process circulation design (through the linkage of the mother liquor tank outlet control valve, the replenishment pump inlet control valve, and the circulation valve) avoids the process short-circuit problem caused by traditional open replenishment methods, ensuring efficient recycling of mother liquor within the system. These improvements increase the process control response speed by more than 50% and significantly reduce operational complexity.

[0043] VI. Safety Interlocks and Automated Flushing Reduce Operational Risks: This system ensures production safety through multiple safety interlock mechanisms: Low-level alarm and automatic replenishment: When the mother liquor storage tank level is too low, the replenishment pump is triggered to prevent the small mother liquor pump from running dry; Remote-controlled warm water valve: Linked with a three-way valve, it enables remote automatic switching of flushing modes, avoiding manual exposure to acid mist; Drain control valve: When the system is shut down, it automatically drains residual mother liquor from the pipelines, reducing the risk of crystallization and blockage. These designs free operators from high-risk environments and reduce the probability of safety accidents caused by human error. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the connection relationship in an embodiment of the present invention.

[0046] In the diagram: 1. Radar level gauge; 2. Steam heater; 3. Anti-frost protection nozzle; 4. Thermal anti-frost protection gas delivery pipe; 5. Mother liquor inlet control valve; 6. Mother liquor circulation control valve; 7. Antifreeze and anti-crystallization blockage circulation pipe; 8. Spray absorption nozzle; 9. Makeup liquid flow meter; 10. Makeup pump; 11. Rinse with warm water; 12. Warm water remote control valve; 13. Mother liquor and warm water makeup and circulation pipes; 14. Mother liquor tank outlet control valve; 15. Drain control valve; 16. Makeup pump inlet control valve; 17. Mother liquor storage tank. Detailed Implementation

[0047] 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.

[0048] like Figure 1 As shown, an automatic detection and replenishment subsystem for mother liquor level in a coking ammonium sulfate system includes:

[0049] Radar level gauge 1 is used to measure the liquid level height of the full flow tank; steam heater 2 heats nitrogen or dried compressed air; anti-frost protection nozzle 3 forms an isolation protective film on the probe surface of radar level gauge 1; thermal anti-frost protection gas delivery pipe 4 delivers heated gas to anti-frost protection nozzle 3; mother liquor inlet control valve 5 controls the on / off flow of mother liquor into the saturator.

[0050] Mother liquor circulation control valve 6 controls the on / off flow of mother liquor circulation; antifreeze and anti-crystallization blockage circulation pipe 7 is used for mother liquor circulation antifreeze and anti-crystallization blockage; spray absorption nozzle 8 sprays mother liquor into French spray saturator; replenishment liquid flow meter 9 measures the flow rate of replenishment mother liquor; replenishment pump 10 provides power for mother liquor transportation; flushing warm water 11 is used for flushing pipes and equipment; warm water remote control valve 12 controls the on / off flow of warm water into the system; mother liquor and warm water replenishment and circulation pipe 13 is the mother liquor and warm water circulation transportation channel; mother liquor tank outlet control valve 14 controls the outflow of mother liquor from the mother liquor tank outlet; venting control valve 15 is used for system venting; replenishment pump 10 inlet control valve controls the inflow of mother liquor into replenishment pump 10; mother liquor storage tank 17 stores mother liquor; French spray saturator is a device for mother liquor to contact with coal gas to absorb ammonia; full flow tank receives and stores mother liquor, maintaining a certain liquid level;

[0051] Radar level gauge 1 is installed above the full flow tank; steam heater 2 heats 0.05-1.0 MPa nitrogen or dried compressed air to 40-80°C using steam as a heat source, and delivers it to anti-frost protection nozzle 3 through thermal anti-frost protection gas delivery pipe 4, forming a continuous and stable isolation protective film on the probe surface of radar level gauge 1; confirm that the venting control valve 15 and the warm water remote control valve 12 are in the closed state; open the mother liquor tank outlet control valve 14, the replenishment pump 10 inlet control valve and the mother liquor circulation operation control valve 6; start the replenishment pump 10 to form a closed-loop process cycle.

[0052] like Figure 1 As shown, the radar level gauge 1 measures the liquid level in the full-flow tank in real time using the high-frequency electromagnetic wave (26GHz) reflection principle, and the signal is transmitted to the PLC controller. When the liquid level is lower than the set lower limit (e.g., 20% of the full-flow tank height), the mother liquor tank outlet control valve 14 and the replenishment pump 10 inlet control valve are automatically opened, and the replenishment pump 10 is started to deliver mother liquor to the full-flow tank; after the liquid level recovers to a safe range (e.g., 40%-80%), the replenishment pump 10 is turned off and the mother liquor circulation control valve 6 is switched to maintain stable system pressure. The steam heater 2 uses steam as a heat source to heat nitrogen or dry compressed air at 0.05-1.0MPa to 40-80℃, and delivers it to the rotary anti-frost protection nozzle 3 through the thermal anti-frost protection gas delivery pipe 4 (with an outer layer wrapped with aerogel felt heat insulation sleeve). The spray direction forms a 5°-30° angle with the surface of the radar level gauge 1 probe, creating a spiral air curtain to cover the probe and prevent the water in the mother liquor from condensing into frost due to low winter temperatures (triggered when the frost temperature is ≤5℃). The antifreeze and anti-crystallization circulation pipe 7 is made of duplex stainless steel 2205, with the inner wall polished to Ra≤0.8μm to reduce ammonium sulfate crystal adhesion. During low-load periods daily (e.g., 0:00-4:00), open the remote-controlled warm water valve 12 and flush the pipe at a flow rate of 5m / s for 10 minutes, maintaining the warm water temperature at 60-70℃ (above the ammonium sulfate crystallization temperature of 55℃).

[0053] The French-style spray saturator is divided into two spray zones: the upper zone is where the spray absorption nozzle 8 sprays the mother liquor at a pressure of 0.3 MPa, which reacts with ammonia (NH3) in the coal gas to generate ammonium sulfate ((NH4)2SO4); the lower zone is where a secondary spray is applied at a pressure of 0.5 MPa to ensure that the crystallization particle size is controlled within the range of 0.5-1.2 mm, thereby improving the efficiency of subsequent centrifugal separation.

[0054] A 316L stainless steel waveguide (50mm diameter) is used, with a drain port at the bottom (for manual drainage of condensate once per shift) to prevent acid tar impurities in the mother liquor from interfering with the measurement. The PLC has a built-in temperature compensation algorithm to correct for the impact of mother liquor density variations (1.2-1.3 g / cm³) on the liquid level reading. The nozzle is driven by a micro stepper motor with adjustable speed (5-30 rpm) to ensure uniform air curtain coverage of the probe surface. A pressure sensor (range 0-1.0 MPa) is installed at the nozzle inlet; when the pressure drops below 0.3 MPa, the PLC interlocks and closes the mother liquor delivery valve and initiates a nitrogen purging procedure.

[0055] When replenishment pump 10 starts, mother liquor circulation control valve 6 remains fully open to reduce pipeline resistance. After the liquid level recovers, the valve opening gradually decreases to 30% to maintain the minimum circulation flow rate (20 m³ / h) and reduce energy consumption. Replenishment pump 10 is frequency-controlled: based on the feedback signal (4-20mA) from replenishment flow meter 9, the pump speed is dynamically adjusted (500-1450 rpm) to achieve precise flow control (error ≤ ±2%). When the storage tank level is below 15% of its capacity, an audible and visual alarm is triggered, and the standby replenishment pump 10 is automatically started. A pneumatic double-acting actuator (opening and closing time ≤ 3 seconds) is used to quickly empty the full-flow tank in emergencies (emptying time ≤ 5 minutes).

[0056] like Figure 1 As shown, the anti-frost protection nozzle 3 is a rotary nozzle with an adjustable spray angle, and its spray direction forms a 5°-30° angle with the surface of the radar level gauge 1 probe. Driven by a micro stepper motor (5-30 rpm), the rotary nozzle sprays heated nitrogen or dry compressed air in a spiral air curtain onto the surface of the radar level gauge 1 probe, forming a continuous isolation layer (thickness ≥ 2 mm) to prevent moisture in the mother liquor from condensing into frost at low temperatures (frost critical temperature ≤ 5℃). The 5°-30° angle design ensures that the air curtain covers the entire probe surface, avoiding local dead zones; the adjustable angle function (via rotating the nozzle body) adapts to different installation scenarios (such as probe tilt or full-flow groove structure limitations). A flow rectifier (0.5 mm aperture) must be installed at the nozzle outlet to ensure uniform airflow distribution and prevent local turbulence from causing the protective film to rupture.

[0057] like Figure 1 As shown, the outer layer of the thermal anti-frost protection gas delivery pipe 4 is wrapped with a heat-insulating sleeve, which is made of aluminum silicate fiber or aerogel felt. Aluminum silicate fiber (thermal conductivity ≤0.035W / (m·K)) or aerogel felt (thermal conductivity ≤0.018W / (m·K)) reduces heat loss and ensures that the gas temperature reaches the nozzle ≥40℃ (for an initial heating temperature of 80℃ and a delivery distance ≤50m). The sleeve joints must be sealed with aluminum foil tape to prevent moisture intrusion and subsequent degradation of insulation performance; the bending radius should be ≥5 times the pipe diameter to avoid sleeve cracking.

[0058] like Figure 1 As shown, the mother liquor circulation control valve 6 is a shut-off valve driven by a pneumatic diaphragm actuator, with an opening and closing time of ≤3 seconds, and is equipped with a valve position feedback sensor. Compressed air (0.4-0.6MPa) drives the diaphragm to deform, pushing the valve stem to achieve rapid opening and closing (≤3 seconds), meeting the emergency response requirements for sudden liquid level changes (such as a sudden drop in liquid level due to blockage at the mother liquor tank outlet). A 4-20mA signal output is used to monitor the valve opening in real time (accuracy ±1%). The PLC interlocks and controls the speed of the replenishment pump 10 based on the feedback signal (e.g., when the valve opening is <30%, the pump operates at a reduced frequency to prevent pipeline pressure buildup). The valve sealing surface needs to be overlaid with hard alloy (hardness HRC≥60) to resist wear from ammonium sulfate crystal particles; in winter, an electric heating tape needs to be wrapped around the pneumatic actuator to prevent the diaphragm from freezing and cracking.

[0059] like Figure 1 As shown, the French-style spray saturator is divided into upper and lower spray zones. Each spray zone is independently equipped with 8 spray absorption nozzles, with nozzle orifice diameters ranging from 1.5 to 3.0 mm. The 1.5-2.0 mm orifice nozzles spray the mother liquor at a pressure of 0.3 MPa, forming fine droplets (average particle size 0.5 mm), increasing the gas contact area and improving ammonia absorption efficiency (absorption rate ≥ 95%). The 2.5-3.0 mm orifice nozzles spray a second time at a pressure of 0.5 MPa, enhancing the collision and aggregation of crystalline particles (target particle size 1.0-1.2 mm), reducing fine crystal loss during subsequent centrifugal separation. The nozzle material must be Hastelloy C-276 (resistant to sulfuric acid corrosion), and the inner wall of the nozzle orifice must be polished to Ra ≤ 0.4 μm to prevent crystallization blockage. Each spray zone must be equipped with a pressure transmitter (range 0-1.0 MPa), which interlocks to shut off the mother liquor circulation valve in case of overpressure.

[0060] like Figure 1 As shown, the mother liquor storage tank 17 is equipped with a lower liquid level alarm device. When the liquid level is lower than the set value, the replenishment pump 10 is triggered to automatically start and open the mother liquor tank outlet control valve 14 until the liquid level returns to a safe range. Liquid level gauge fault redundancy needs to be configured (e.g., installing ultrasonic level gauges simultaneously). When any sensor alarms, the system switches to manual control mode. The valve drive air source needs to be equipped with a dryer (dew point ≤ -40℃) to prevent ice blockage.

[0061] like Figure 1 As shown, the warm water pipeline 11 for rinsing is connected to the mother liquor circulation pipeline via a three-way valve. This three-way valve is an electrically adjustable valve that automatically switches between the warm water and mother liquor flow paths depending on the rinsing mode. With the valve open at 100%, warm water (60-70℃) is used to rinse the pipeline for 10 minutes at a flow rate of 3 m / s to dissolve ammonium sulfate crystals. The valve then closes the warm water path and fully opens the mother liquor path to maintain normal production. A V-type ball valve (with percentage-based flow characteristics) must be selected to ensure adjustment accuracy at small openings. The valve body is made of 316L stainless steel and lined with polytetrafluoroethylene (PTFE) to resist corrosion from warm water.

[0062] like Figure 1 As shown, a vent valve is installed at the top of the full-flow tank. The vent valve opens at a pressure of 0.02-0.05 MPa to balance the pressure inside the tank and prevent mother liquor from overflowing. The vent valve uses a spring-loaded structure (opening pressure 0.02-0.05 MPa). When the pressure inside the tank exceeds the set value (such as rapid injection of mother liquor causing compression of the gas phase space), the valve automatically opens to release gas; after the pressure returns to normal, the spring resets and closes the valve. A stainless steel filter screen (80 mesh) must be installed at the outlet of the vent valve to prevent dust or crystalline particles from entering the tank; the valve opening pressure must be manually tested quarterly (using a pressure calibrator), and the spring should be replaced if the error exceeds the limit.

[0063] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. An automatic mother liquor level detection and replenishment subsystem in a coking ammonium sulfate system, characterized in that, include; Radar level gauge (1) is used to measure the liquid level height of a full-flow tank; Steam heater (2) heats nitrogen or dried compressed air; Anti-frost protection nozzle (3) forms an isolation protective film on the probe surface of radar level gauge (1); The heat-resistant anti-frost protection gas delivery pipe (4) delivers heated gas to the anti-frost protection nozzle (3); The mother liquor inlet control valve (5) controls the on / off flow of mother liquor into the saturator; Mother liquor circulation control valve (6) controls the on / off state of the mother liquor circulation process; Antifreeze and anti-crystallization circulation pipe (7) is used for mother liquor circulation antifreeze and anti-crystallization blockage; Spray absorption nozzle (8) to spray the mother liquor into the French spray saturator; The replenishment liquid flow meter (9) measures the flow rate of the replenishment mother liquid; The replenishment pump (10) provides power for the delivery of the mother liquor; Warm water (11) is used to flush pipes and equipment; The remote control valve (12) for warm water controls the on / off flow of warm water into the system. Mother liquor and warm water replenishment and circulation pipeline (13), mother liquor and warm water circulation and transportation channel; The mother liquor tank outlet control valve (14) controls the outflow of mother liquor from the mother liquor tank outlet; A venting control valve (15) is used for system venting; The inlet control valve of the replenishment pump (10) controls the entry of the mother liquor into the inlet of the replenishment pump (10); Mother liquor storage tank (17) for storing mother liquor; French spray saturator, a device for absorbing ammonia by contacting mother liquor with coal gas; A full-flow tank receives and stores the mother liquor, maintaining a certain liquid level. The radar level gauge (1) is installed above the full flow tank; the steam heater (2) heats 0.05-1.0 MPa nitrogen or dried compressed air to 40-80°C with water vapor as the heat source, and delivers it to the anti-frost protection nozzle (3) through the thermal anti-frost protection gas delivery pipe (4), forming a continuous and stable isolation protection film on the probe surface of the radar level gauge (1); Confirm that the venting control valve (15) and the warm water remote control valve (12) are closed; open the mother liquor tank outlet control valve (14), the replenishment pump (10) inlet control valve and the mother liquor circulation operation control valve (6); start the replenishment pump (10) to form a closed-loop process cycle.

2. The automatic detection and replenishment subsystem for mother liquor level in a coking ammonium sulfate system according to claim 1, characterized in that, The anti-frost protection nozzle (3) is a rotary nozzle with an adjustable spray angle, and its spray direction forms a 5°-30° angle with the probe surface of the radar level gauge (1).

3. The automatic detection and replenishment subsystem for mother liquor level in a coking ammonium sulfate system according to claim 1, characterized in that, The outer layer of the heat-resistant frosting protective gas delivery pipe (4) is wrapped with a heat-insulating sleeve, which is made of aluminum silicate fiber or aerogel felt.

4. The automatic detection and replenishment subsystem for mother liquor level in a coking ammonium sulfate system according to claim 1, characterized in that, The mother liquor circulation control valve (6) is a shut-off valve driven by a pneumatic diaphragm actuator, with an opening and closing time of ≤3 seconds, and is equipped with a valve position feedback sensor.

5. The automatic detection and replenishment subsystem for mother liquor level in a coking ammonium sulfate system according to claim 1, characterized in that, The French-style spray saturator is divided into upper and lower spray zones. Each spray zone is independently equipped with a spray absorption nozzle (8), and the nozzle orifice diameter is 1.5-3.0mm.

6. The automatic detection and replenishment subsystem for mother liquor level in a coking ammonium sulfate system according to claim 1, characterized in that, The mother liquor storage tank (17) is equipped with a liquid level lower limit alarm device. When the liquid level is lower than the set value, the replenishment pump (10) is triggered to start automatically and open the mother liquor tank outlet control valve (14) until the liquid level is restored to the safe range.

7. The automatic detection and replenishment subsystem for mother liquor level in a coking ammonium sulfate system according to claim 1, characterized in that, The warm water (11) pipeline for rinsing is connected to the mother liquor circulation pipeline through a three-way valve. The three-way valve is an electric regulating valve that can automatically switch the flow path of warm water or mother liquor according to the rinsing mode.

8. The automatic detection and replenishment subsystem for mother liquor level in a coking ammonium sulfate system according to claim 1, characterized in that, The top of the full-flow tank is equipped with a vent valve, which opens at a pressure of 0.02-0.05 MPa to balance the pressure inside the tank and prevent the mother liquor from overflowing.

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