A chemical injection control system for a pyrolysis gasoline hydrogenation unit

Abstract

The utility model relates to industrial injection control field, specifically disclose a kind of for cracking gasoline hydrogenation device chemical injection control system, including storage tank and the output module of the reactant material export in the storage tank, the output module quantity has multiple groups, and is connected in parallel;The top of the storage tank is connected with double medium conveying unit, safety module and comprehensive monitoring unit;The output module includes metering pump, the metering pump feed end is communicated with the storage tank bottom end by discharge valve, its discharge end is connected with external reaction bin, the input end pipeline of the metering pump is equipped with calibration column, and the calibration column top end is equipped with reflux line between the high end of the storage tank. Advantage lies in: multiple groups of parallelly connected output module can realize the multiple synchronous or independent delivery of reactant material, effectively improve the flexibility of material injection and the redundancy of system operation;Utilize the mutual cooperation of double medium conveying unit, safety module, comprehensive monitoring unit, avoid material oxidation and safety risk problem.

Description

Technical Field

[0001] This utility model relates to the field of industrial injection control, specifically to a chemical injection control system for a cracked gasoline hydrogenation unit. Background Technology

[0002] Gasoline hydrogenation in ethylene cracking units is an important chemical process used to process crude cracked gasoline, a byproduct of ethylene plants, to produce high-quality hydrogenated gasoline. This process involves the application of a chemical injection control system, which primarily works by adding specific chemical reagents to control reaction conditions, thereby improving reaction efficiency and product quality.

[0003] In the hydrotreating process of cracked gasoline, the main function of the dosing system is to add catalysts or regulators to the reaction system. These agents help control the reaction rate, selectivity, and product purity. The dosing system can precisely control the amount and timing of catalyst addition, thereby optimizing reaction conditions. The principle of the ethylene cracked gasoline hydrotreating dosing system is to optimize the hydrotreating reaction conditions by precisely controlling the addition of agents, thereby improving reaction efficiency and product quality.

[0004] In the hydrocracking process of gasoline, the types of reagents added to the material include corrosion inhibitors and polymerization inhibitors. These materials are prone to oxidation and deterioration when they come into contact with air, which affects the injection effect. The metering pumps of traditional injection systems lack online calibration methods, and long-term operation is prone to metering deviations, resulting in over- or under-addition of reagents. Summary of the Invention

[0005] The purpose of this invention is to provide a chemical injection control system for a cracked gasoline hydrogenation unit to solve the problems existing in the prior art.

[0006] The purpose of this utility model is achieved as follows: a chemical injection control system for a cracked gasoline hydrogenation unit, comprising a storage tank and an output module for exporting reactants from the storage tank, characterized in that: the output module comprises multiple sets and is arranged in parallel; The top of the storage tank is connected to a dual-medium delivery unit, a safety module, and a comprehensive monitoring unit; the output module includes a metering pump, the inlet of which is connected to the bottom of the storage tank through a discharge valve, and the outlet of which is connected to an external reaction chamber. A calibration column is provided at the input pipe of the metering pump, and a return pipeline is provided between the top of the calibration column and the high end of the storage tank.

[0007] Furthermore, the metering pump is a hydraulic double diaphragm metering pump, whose input pipe is connected to the bottom of the storage tank, and whose output pipe is connected to the external reaction chamber through a check valve.

[0008] Furthermore, the output pipeline of the metering pump is equipped with a pump outlet pressure gauge and a buffer. The buffer has a capacity greater than 10 times the capacity of a single reciprocating motion of the metering pump diaphragm, and is used to reduce the flow pulsation of the material output by the metering pump.

[0009] Furthermore, a pipeline safety valve is also provided on the pipeline between the metering pump output pipeline and the buffer, and the set pressure of the pipeline safety valve is matched with the outlet pressure of the metering pump.

[0010] Furthermore, the dual-medium conveying unit includes a feed pump, the outlet pipeline of which is connected to the high end of the storage tank, a one-way valve is provided on the outlet pipeline of the feed pump, the air inlet of the feed pump is connected to an inert gas source pipeline, and the liquid inlet of the feed pump is connected to a material source pipeline.

[0011] Furthermore, the safety module includes a pressure relief component and a nitrogen blanketing protection component; the pressure relief component includes a lead-sealed closed valve, a self-operated pressure relief valve, and a lead-sealed open valve arranged in series between the top of the storage tank and the exhaust pipe, which automatically release pressure when the pressure in the storage tank exceeds a preset safety value; the nitrogen blanketing protection component includes a manual switch valve A, a self-operated pneumatic regulating valve, and a manual switch valve B arranged in series at the top of the storage tank, which automatically replenishes or releases nitrogen when the pressure in the storage tank changes; there are two sets of nitrogen blanketing protection components, which are respectively connected in series between the storage tank and the exhaust pipe, and between the storage tank and the inert gas source pipe.

[0012] Furthermore, the pressure relief components are in two sets and are connected in parallel.

[0013] Furthermore, the integrated monitoring unit includes a local level gauge and a remote level gauge for monitoring the liquid level in the storage tank, and a tank top near-end pressure gauge and a tank top pressure transmitter for monitoring the pressure in the storage tank. The remote level gauge and the tank top pressure transmitter are used to transmit the monitoring data to the terminal electrical control equipment in the central control room.

[0014] Positive and beneficial effects: Multiple parallel output modules enable simultaneous or independent multi-path delivery of reactants, effectively improving the flexibility of material filling and the redundancy of system operation, avoiding equipment downtime due to single-path failure; the dual-media delivery unit isolates the material inside the tank from air, preventing oxidation and deterioration, and, in conjunction with the safety module, can promptly release abnormal pressure inside the tank, ensuring system safety and resolving material oxidation and safety issues; the calibration column and reflux pipeline structure enable real-time online calibration of the metering pump, ensuring filling accuracy; and the reflux pipeline can return excess material to the storage tank, solving the problem of material waste, preventing metering pump cavitation, and extending equipment life. Attached Figure Description

[0015] Figure 1This is a schematic diagram of the pipeline of this utility model; Figure 2 This is a schematic diagram of the pipeline of the safety module of this utility model; The diagram shows: 1. Metering pump; 2. Calibration column; 3. Discharge valve; 4. Local level gauge; 5. Storage tank; 6. Remote level gauge; 7. Feed pump; 8. Tank top pressure transmitter; 9. Tank top near-end pressure gauge; 10. Pressure relief assembly; 11. Nitrogen blanketing protection assembly; 12. Buffer; 13. Pipeline safety valve; 14. Check valve; 15. Pump outlet pressure gauge. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] See Figure 1-2 As shown, this utility model provides a chemical injection control system for a cracked gasoline hydrogenation unit, including a storage tank 5 and an output module for exporting the reactants from the storage tank 5. The system has multiple sets of output modules connected in parallel. The number of output modules can be flexibly adjusted according to the amount of material reacted in the cracked gasoline hydrogenation reaction. This allows for simultaneous multi-pipeline delivery to improve injection efficiency, or the individual use of some output modules for precise, low-flow delivery. The parallel structure also provides redundancy; if one set of output modules fails, the remaining modules can continue to operate normally, preventing a single-path failure from causing a shutdown of the entire chemical injection control system and ensuring the continuous and stable operation of the hydrogenation unit.

[0018] The top of storage tank 5 is connected to a dual-media conveying unit, a safety module, and a comprehensive monitoring unit. The comprehensive monitoring unit can comprehensively monitor and collect parameters such as pressure and material level inside storage tank 5 in real time, and the parameters can provide a basis for starting and stopping the dual-media conveying unit. When the pressure inside the tank is detected to be higher than the set threshold, the safety module starts the pressure relief operation. When the pressure is lower than the set threshold, the dual-media conveying unit replenishes inert gas to ensure that the pressure inside the tank is always maintained within a safe range.

[0019] The output module includes a metering pump 1. The inlet of the metering pump 1 is connected to the outlet pipe at the bottom of the storage tank 5 through the outlet valve 3. Its outlet is connected to the external reaction chamber. The metering pump 1 in the output module can stably extract the reaction material in the tank. Since there is a certain pressure in the storage tank 5, it can help the material to be evenly pumped to the external reaction chamber by the metering pump 1. The input pipe of the metering pump 1 is equipped with a calibration column 2 with millimeter scale indication. During operation, the delivery accuracy of the metering pump 1 can be verified and adjusted by observing the change of material level in the calibration column 2. The flow accuracy of the metering pump 1 can be calibrated periodically. A return pipe is provided between the top of the calibration column 2 and the top cover of the storage tank 5. When the reagent overflows from the top of the calibration column 2, it can be discharged into the storage tank 5 through the return pipe, avoiding the leakage of reagent into dangerous areas and environmental pollution. At the same time, it can also realize the recovery of reagent.

[0020] The second embodiment differs from the first embodiment in that: Metering pump 1 is a hydraulic double diaphragm metering pump. The metering pump diaphragm is made of PTFE, which is suitable for the stable conveying of medium viscosity reactants with a kinematic viscosity of 50-100 mm² / s at 25°C. Its feed end is connected to the discharge pipe at the bottom of storage tank 5 through a valve, which can accurately extract the material in the tank and avoid the accumulation of material that may block the pipeline. The discharge end is connected to the external reaction chamber through check valve 14. Check valve 14 can effectively prevent the material in the reaction chamber from flowing back to metering pump 1 or storage tank 5, protect the internal components of metering pump 1 from backflow impact damage, and ensure the unidirectional stability of the conveying process.

[0021] A pump outlet pressure gauge 15 and a buffer 12 are installed side-by-side at the outlet pipeline of metering pump 1. The pump outlet pressure gauge 15 can monitor the output pressure of metering pump 1 in real time and is used to detect diaphragm rupture. The pump outlet pressure gauge 15 can help operators intuitively grasp the material conveying pressure status, detect pressure abnormalities in a timely manner, and make adjustments to reduce the risk of pipeline overpressure. The capacity of buffer 12 is set to be no less than 10 times the single-stroke capacity of metering pump 1. The top of buffer 12 is connected to a nitrogen pipeline, which can maintain the pressure stability inside buffer 12 by replenishing inert gas, thereby reducing the pressure of metering pump 1. The flow pulsation generated during material output is prevented from causing pipeline vibration or a decrease in material conveying accuracy due to pulsation impact, ensuring the continuity and stability of the hydrogenation reaction feed. A pipeline safety valve 13 is installed on the pipeline between the outlet of metering pump 1 and buffer 12. Its set pressure matches the working pressure of storage tank 5. When the pressure in the outlet pipeline of metering pump 1 rises abnormally due to sudden situations such as blockage or valve malfunction, the pipeline safety valve 13 will automatically open to release pressure, controlling the pipeline pressure within the safe threshold, effectively protecting the metering pump 1, buffer 12 and outlet pipeline from overpressure damage.

[0022] The third embodiment differs from the first embodiment in that: The dual-medium conveying unit includes a feed pump 7, whose air inlet is connected to an external inert gas source pipeline, and whose liquid outlet extends through a pipeline to the top of the storage tank 5 and is sealed. A one-way valve is installed on the connecting pipeline between the feed pump 7 and the storage tank 5, and the liquid inlet of the feed pump 7 is connected to an external material source pipeline. In this structure, the feed pump 7 is pneumatically driven, and an electrically controlled valve is installed at the pipeline between the feed pump 7 and the external inert gas source pipeline. This electrically controlled valve is electrically connected to the terminal electrical control equipment in the central control room. The electrically controlled valve can automatically start when the pressure in the storage tank 5 is lower than a set threshold based on the pressure signal fed back by the integrated monitoring unit. It uses inert gas to drive the feed pump 7 to assist in the material conveying to the inside of the storage tank 5, quickly replenishing the material in the storage tank 5 and restoring it to the set range. The one-way valve can strictly restrict the unidirectional flow of gas, effectively preventing the reaction materials, gases, or condensates in the storage tank 5 from flowing back into the feed pump 7.

[0023] The safety module includes a pressure relief component 10 and a nitrogen sealing protection component 11. Both components are connected in parallel on the top of the storage tank 5, and there are two of each component. This dual parallel structure provides redundancy for the pressure regulation and nitrogen sealing protection of the storage tank 5, and avoids system failure when a single component fails.

[0024] Specifically, the pressure relief assembly 10 includes a lead-sealed shut-off valve, a self-operated pressure relief valve, and a lead-sealed open valve, which are sequentially connected in series between the top of the storage tank 5 and the exhaust pipe. The lead-sealed shut-off valve is connected to the pipe at the top of the storage tank 5. When the pressure inside the storage tank 5 exceeds a preset safety value, the self-operated pressure relief valve automatically releases the pressure, and the lead-sealed open valve quickly releases the overpressure gas inside the tank until the pressure inside the tank drops to a safe range and then automatically closes. This achieves automatic and precise pressure control, avoiding safety risks such as deformation and leakage of the storage tank 5 due to overpressure, and protecting the storage tank 5 and the materials stored inside. The lead-sealed shut-off / open valves are effectively prevented from being operated by unauthorized personnel through lead sealing, ensuring the standardized operation of the assembly.

[0025] The nitrogen blanketing protection component 11 includes a manual switch valve A, a flow regulating valve, and a manual switch valve B arranged in series. Manual switch valves A and B can be shut off during the inspection and maintenance of the nitrogen blanketing protection component 11, facilitating the operation of the flow regulating valve independently and avoiding impact on the overall operation of the storage tank 5. The middle flow regulating valve is an electrically controlled valve and is electrically connected to the terminal electrical control equipment in the central control room. Based on parameters such as tank pressure and inert gas concentration fed back by the integrated monitoring unit, the opening degree of the flow regulating valve is precisely adjusted to ensure stable nitrogen blanketing pressure and that the inert gas concentration in the tank meets the standards.

[0026] There are two sets of nitrogen sealing protection components 11, which are connected in series between the storage tank 5 and the exhaust pipe, and between the storage tank 5 and the inert gas source pipe, respectively. The nitrogen sealing protection component 11 located between the storage tank 5 and the exhaust pipe can assist the storage tank 5 in depressurization, and the nitrogen sealing protection component 11 located between the storage tank 5 and the inert gas source pipe can assist the storage tank 5 in supplying inert gas.

[0027] Furthermore, the nitrogen sealing protection component 11 also includes a lead-sealed shut-off valve connected in parallel with the three valves: manual switch valve A, flow regulating valve, and manual switch valve B. This valve serves as a backup emergency channel and can be opened by breaking the lead seal in case of main valve failure or emergency, ensuring that the nitrogen sealing protection function is not interrupted and improving the fault tolerance and safety of the component operation.

[0028] The integrated monitoring unit includes a local level gauge 4 and a remote level gauge 6 for monitoring the liquid level of storage tank 5, and a tank top near-end pressure gauge 9 and a tank top pressure transmitter 8 for monitoring the pressure of storage tank 5. The remote level gauge 6 and the tank top pressure transmitter 8 are used to transmit monitoring data to the terminal electrical control equipment in the central control room. Specifically, the local level gauge 4 and the remote level gauge 6 are both installed on the side wall of storage tank 5. The local level gauge 4 allows operators to intuitively read the real-time liquid level of the reactants in the tank, quickly confirm the material inventory, and determine whether replenishment is needed. The remote level gauge 6 transmits the liquid level data to the terminal electrical control equipment in the central control room in real time through signal transmission, realizing remote monitoring, recording, and abnormal early warning of the liquid level. When the liquid level reaches the preset upper or lower limit, it can trigger a material replenishment reminder or start / stop control of related conveying components to avoid material overflow or damage to the metering pump 1 due to lack of material, thereby improving the automation and intelligence level of liquid level management.

[0029] Meanwhile, the integrated monitoring unit, equipped with a tank top pressure transmitter 8 and a tank top near-end pressure gauge 9, forms a dual pressure monitoring system: the tank top pressure transmitter 8 can collect pressure data inside the storage tank 5 in real time and convert it into an electrical signal for transmission to the terminal electrical control equipment in the central control room. When the pressure inside the storage tank 5 is high, it provides a trigger signal for the pressure relief action of the safety module, ensuring that the pressure inside the storage tank 5 is automatically maintained within a safe range; the tank top near-end pressure gauge 9 is installed at an easily observable position on the top of the storage tank 5, allowing operators to directly read the pressure value on-site and compare it with the remotely transmitted pressure data to promptly detect monitoring deviations or equipment malfunctions, providing an intuitive reference for system maintenance and troubleshooting, and further ensuring the accuracy and reliability of pressure monitoring.

[0030] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A chemical injection control system for a cracked gasoline hydrogenation unit, comprising a storage tank (5) and an output module for exporting reactants from the storage tank (5), characterized in that... The output modules are in multiple groups and are connected in parallel. The top of the storage tank (5) is connected to a dual-media delivery unit, a safety module and a comprehensive monitoring unit; The output module includes a metering pump (1), the feed end of the metering pump (1) is connected to the bottom end of the storage tank (5) through the discharge valve (3), and its discharge end is connected to the external reaction chamber. A calibration column (2) is provided at the input end pipe of the metering pump (1), and a return pipeline is provided between the top of the calibration column (2) and the high end of the storage tank (5).

2. The chemical injection control system for a cracked gasoline hydrogenation unit according to claim 1, characterized in that: The metering pump (1) is a hydraulic double diaphragm metering pump. Its input pipe is connected to the bottom of the storage tank (5), and its output pipe is connected to the external reaction chamber through the check valve (14).

3. A chemical injection control system for a cracked gasoline hydrogenation unit according to claim 2, characterized in that: The metering pump (1) is provided with a pump outlet pressure gauge (15) and a buffer (12) at the output pipeline. The buffer (12) has a capacity greater than 10 times the capacity of the metering pump (1) diaphragm reciprocating once, and is used to reduce the flow pulsation of the output material of the metering pump (1).

4. A chemical injection control system for a cracked gasoline hydrogenation unit according to claim 3, characterized in that: A pipeline safety valve (13) is also provided on the pipeline between the output pipeline of the metering pump (1) and the buffer (12), and the set pressure of the pipeline safety valve (13) matches the outlet pressure of the metering pump (1).

5. A chemical injection control system for a cracked gasoline hydrogenation unit according to claim 1, characterized in that: The dual-medium conveying unit includes a feed pump (7), the outlet pipeline of the feed pump (7) is connected to the high end of the storage tank (5), a one-way valve is provided on the outlet pipeline of the feed pump (7), the air inlet of the feed pump (7) is connected to an inert gas source pipeline, and the liquid inlet of the feed pump (7) is connected to a material source pipeline.

6. A chemical injection control system for a cracked gasoline hydrogenation unit according to claim 1, characterized in that: The safety module includes a pressure relief assembly (10) and a nitrogen blanketing protection assembly (11). The pressure relief assembly (10) includes a lead-sealed shut-off valve, a self-operated pressure relief valve, and a lead-sealed open valve, which are connected in series between the top of the storage tank (5) and the exhaust pipe. The pressure is automatically released when the pressure in the storage tank (5) exceeds a preset safety value. The nitrogen sealing protection component (11) includes a manual switch valve A, a self-operated pneumatic regulating valve and a manual switch valve B arranged in series on the top of the storage tank (5), which automatically replenish or release nitrogen when the pressure inside the storage tank (5) changes; There are two sets of nitrogen sealing protection components (11), which are connected in series between the storage tank (5) and the exhaust pipe, and between the storage tank (5) and the inert gas source pipe, respectively.

7. A chemical injection control system for a cracked gasoline hydrogenation unit according to claim 6, characterized in that: The pressure relief assembly (10) consists of two sets, which are connected in parallel.

8. A chemical injection control system for a cracked gasoline hydrogenation unit according to claim 1, characterized in that: The integrated monitoring unit includes a local level gauge (4) and a remote level gauge (6) for monitoring the liquid level of the storage tank (5), and a tank top near-end pressure gauge (9) and a tank top pressure transmitter (8) for monitoring the pressure of the storage tank (5). The remote level gauge (6) and the tank top pressure transmitter (8) are used to transmit the monitoring data to the terminal electrical control equipment in the central control room.

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