Coal gasification high-pressure ash water frequency conversion automatic control system
By introducing a variable frequency automatic control system into the coal gasification system, and by using a high-temperature hot water pump and a DCS controller to optimize the flow and pressure regulation of high-pressure ash water, the problem of easy damage to high-pressure angle valves was solved, and stable operation of the equipment and cost reduction were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG PETROLEUM&CHEM CO LTD
- Filing Date
- 2025-04-15
- Publication Date
- 2026-05-29
AI Technical Summary
In existing coal gasification systems, the angle valves for high-pressure ash water are prone to damage under high pressure differential conditions, resulting in high equipment failure rates, high maintenance costs, and difficulty in pressure control during start-up and shutdown, which affects the operating cycle and safety of the gasifier.
The system adopts a variable frequency automatic control system, which realizes stable regulation of high-pressure grey water flow and pressure through a high-temperature hot water pump and a DCS controller. The high-pressure angle valve is eliminated, and the operation of the high-temperature hot water pump is optimized by using pressure sensors and variable frequency technology, thereby reducing equipment damage and failure rate under high pressure differential conditions.
It effectively reduced the failure rate of high-pressure angle valves, extended the service life of equipment, reduced maintenance costs, improved the operational stability and cycle of gasifiers, and reduced the risk of production fluctuations.
Smart Images
Figure CN224299165U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an automatic control system, and more specifically, to a frequency conversion automatic control system for high-pressure ash water in coal gasification, belonging to the field of petrochemicals. Background Technology
[0002] Currently, the coal gasification industry is divided into two main categories: coal-water slurry gasification and pulverized coal gasification. The mainstream operating pressure in the gasification industry is 6.5 MPa. Regardless of whether it's coal-water slurry gasification or pulverized coal gasification, a syngas scrubbing tower is installed. High-pressure ash water and condensate are added to the syngas scrubbing tower to wash and purify the syngas produced by the gasifier, ensuring that the dust content of the crude syngas sent for purification is less than 1 mg / m³. 3 In the coal gasification industry, high-pressure ash water is typically supplied to the scrubbing tower using a multi-stage centrifugal pump. The outlet pressure of the multi-stage centrifugal pump is approximately 8.0 MPa. An angle valve is installed at the outlet of the centrifugal pump to control the outlet pressure of the high-pressure ash water, ensuring that the high-pressure ash water can enter the scrubbing tower, which operates at a normal pressure of 6.5 MPa, during normal operation.
[0003] During normal operation of the gasifier, the scrubbing tower is at atmospheric pressure, while the high-pressure ash water pressure is 8.0 MPa, resulting in a significant pressure difference. Even with angle valves for pressure reduction, the ash water pressure reduction effect is not significant, and overpressure may still occur at the outlet of the multi-stage centrifugal pump. Therefore, reflux and outlet angle valves are needed for control to prevent pump damage due to overpressure. When the angle valve opening is too small, the valve and pipeline vibrate significantly. Prolonged vibration can easily cause pipeline displacement and valve core detachment. When such abnormalities occur, it can easily lead to overflow and overpressure at the pump outlet, causing pump damage. Since the high-temperature hot water pump is a crucial pump in the gasification process, if it fails and cannot operate, the gasifier may need to reduce its load or even shut down, resulting in substantial losses. Furthermore, damage to such high-pressure valves is generally not repairable online and requires the gasifier to be shut down for repair, which is costly.
[0004] The gasifier operates normally for 60-90 days. When the burner reaches the end of its service life, it will be shut down for replacement. During the shutdown and startup of the gasifier, the pressure of the scrubbing tower will change from 0 to 6.5 MPa. During this process, it is very difficult to control the high-pressure ash water pressure using angle valves, which has a significant impact on the service life of valves and pumps and results in a high failure rate. When the water supply to the scrubbing tower is interrupted, it may cause safety accidents such as overheating of the scrubbing tower outlet pipeline and damage to the internal components of the scrubbing tower. Utility Model Content
[0005] To address the aforementioned technical problems, this utility model provides a coal gasification high-pressure ash water frequency conversion automatic control system that features the ability to completely eliminate the failure rate of high-pressure angle valves in high-pressure differential conditions, extend the service life of important equipment, reduce valve failure and maintenance costs, extend the gasifier's operating cycle, and reduce the risk of production fluctuations.
[0006] To achieve the above objectives, this utility model is implemented through the following technical solution:
[0007] This utility model discloses a variable frequency automatic control system for high-pressure ash water from coal gasification, comprising a gasifier, a scrubbing tower, a high-temperature hot water tank, and a high-temperature hot water pump. The gasifier is connected to the middle of the scrubbing tower via a No. 1 pipeline. The outlet end of the middle of the scrubbing tower is connected to a No. 2 pipeline. The No. 2 pipeline is further divided into a No. 3 pipeline and a No. 4 pipeline. The No. 3 pipeline is connected to the upper part of the scrubbing tower and a No. 1 shut-off valve is connected to it. The No. 4 pipeline is connected to a variable frequency high-temperature hot water pump and a No. 2 shut-off valve, and is connected to the inlet at the lower end of the high-temperature hot water tank.
[0008] Preferably, the high-temperature hot water pump has a voltage of 380V and is connected to a DCS controller.
[0009] Preferably, pressure sensors are connected to both the first and second shut-off valves. The pressure sensors are communicatively connected to the high-temperature hot water pump and are also connected to the DCS controller.
[0010] Preferably, a No. 3 shut-off valve is connected to the No. 2 pipeline and the No. 3 pipeline, the No. 3 shut-off valve on the No. 2 pipeline is connected in parallel to the lower tower water supply regulating valve of the washing tower, and the No. 3 shut-off valve on the No. 3 pipeline is connected in parallel to the upper tower water supply regulating valve of the washing tower.
[0011] Preferably, the third pipeline is connected to the fifth tray of the scrubbing tower to achieve scrubbing of the syngas.
[0012] Beneficial effects: By using frequency conversion and flow cascade control, the high-pressure ash water outlet flow and high-temperature hot water pump pressure can be stably regulated. This can reduce the potential problems of high-pressure ash water pumps in dealing with high pressure differential conditions during start-up and shutdown, completely eliminate the failure rate of high-pressure angle valves in dealing with high pressure differential conditions, extend the service life of important equipment, reduce valve failure and maintenance costs, extend the gasifier operating cycle, and reduce the risk of production fluctuations. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the principle of this utility model. Detailed Implementation
[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0015] In the description of the utility model, it should be noted that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the utility model.
[0016] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0017] like Figure 1 The illustration shows a specific embodiment of a variable frequency automatic control system for high-pressure ash water in coal gasification. This embodiment of the high-pressure ash water variable frequency automatic control system for coal gasification includes a gasifier 1, a washing tower 2, a high-temperature hot water tank 4, and a high-temperature hot water pump 5. The middle part of the gasifier 1 is connected to the middle part of the washing tower 2 via a No. 1 pipeline. The outlet end of the middle part of the washing tower 2 is connected to a No. 2 pipeline. The No. 2 pipeline is further divided into a No. 3 pipeline and a No. 4 pipeline. The No. 3 pipeline is connected to the upper part of the washing tower 2 and a No. 1 shut-off valve is connected to the No. 3 pipeline. The No. 4 pipeline is connected to the variable frequency high-temperature hot water pump 5 and the No. 2 shut-off valve. The No. 4 pipeline is connected to the water inlet at the lower end of the high-temperature hot water tank 4.
[0018] High-pressure ash water ≈ 280m 3At 235℃ and 7.5 MPa, the washing water for syngas is relatively clean, but the ash water pressure is high, especially during start-up and shutdown. The pressure fluctuations in the washing tower are significant, resulting in large pressure differences across the traditionally designed high-pressure angle valves. These pressure differences can reach up to 8.0 MPa during start-up and after depressurization. Under these conditions, the angle valves, pump impellers, and rotors experience severe wear and erosion. Traditionally designed angle valves are particularly difficult to adjust, resulting in small valve openings and significant vibration during start-up and shutdown. In actual production start-up and commissioning, the valve core may detach due to excessive vibration, forcing a shutdown for maintenance. Furthermore, angle valve maintenance is costly because the internal components are typically made of integral tungsten carbide or welded STL materials to withstand high pressure differences, leading to high repair costs.
[0019] This application designs a high-temperature hot water pump with variable frequency control, which can change the voltage of the traditional high-temperature hot water pump from 1000V to 380V and eliminate the need for a high-pressure grey water angle valve. During start-up, shutdown, and daily stable operation, when adjusting the high-pressure grey water flow, the DCS controller, a mature existing technology, allows operators to control the flow by adjusting the high-temperature hot water pump's frequency converter. The operation is simple and stable. Furthermore, during start-up and shutdown, the frequency converter's self-adjustment control directly avoids damage to the pump caused by high pressure differentials and the difficulty of adjusting angle valves, greatly improving operational stability. The high-pressure grey water pump frequency converter reduces energy consumption and operating costs under low high-pressure grey water flow conditions during start-up and shutdown. Eliminating the high-pressure angle valve reduces valve maintenance costs and also lowers the valve failure rate during start-up and shutdown, improving stability.
[0020] Workflow: The high-pressure ash water in the high-temperature hot water tank 4 is pressurized by the high-pressure ash water pump, i.e., the high-temperature hot water pump 5, and enters the scrubbing tower 2 through two paths. One path enters the fifth tray of the scrubbing tower 2 via pipeline No. 3 to scrub the syngas. The other path enters the lower part of the scrubbing tower 2 via pipeline No. 4 for level adjustment. During operation, the high-temperature hot water pump is controlled by frequency converter in real time to regulate pressure and flow. This effectively solves the safety hazards caused by the current operation and reduces production and operating costs. Specifically, it is reflected in the following aspects: the high-temperature hot water pump voltage is reduced from 1000V to 380V, reducing operating costs; the high-pressure ash water angle valve is eliminated, reducing the maintenance cost of the original valve; the use of frequency converter control for the high-temperature hot water pump greatly reduces the difficulty of ash water adjustment during high-pressure differential conditions during gasifier start-up and shutdown, and reduces the failure rate; the high-pressure ash water can be automatically controlled by frequency converter with the high-temperature hot water pump, and frequency converter adjustment can be used for start-up, shutdown, and stable operation, greatly improving operational stability.
[0021] The existing technology DCS (Distributed Control System) is a key component in the field of industrial automation, responsible for monitoring and controlling various parameters and equipment in industrial processes.
[0022] The following is a detailed introduction to the structure and design principles of DCS controllers:
[0023] I. Structure A typical DCS controller comprises the following core components: Processor Unit: The core of the DCS controller, responsible for executing control algorithms, data processing, and communication tasks. The processor unit typically uses a high-performance microprocessor or digital signal processor (DSP) to meet real-time and reliability requirements. Input / Output Modules (I / O Modules): Responsible for data exchange with field devices, including sensors, actuators, valves, etc. I / O modules include analog input / output modules and digital input / output modules, used to process different types of signals. Communication Interface: Used for communication with other DCS components such as operator stations, engineer stations, and other controllers. Common communication protocols include Ethernet, fieldbuses such as Modbus and PROFIBUS, and proprietary communication protocols. Power Supply Module: Provides a stable and reliable power supply to the controller. Redundancy is typically used to improve system reliability and availability. Storage Unit: Used to store control algorithms, configuration parameters, historical data, etc. The storage unit typically uses non-volatile memory to ensure data is not lost during power outages.
[0024] II. Design Principles The design principles of the DCS controller are primarily based on the following aspects: Distributed Control: Control tasks are distributed across multiple controllers, each responsible for controlling a specific industrial process or equipment. This design improves system reliability and flexibility, reducing the impact of a single controller failure on the entire system. Modular Design: The controller adopts a modular design, facilitating expansion and maintenance. Users can add or remove I / O modules, communication interfaces, and other components according to actual needs to adapt to different industrial application scenarios. Real-Time Performance: The controller needs to respond quickly to signal changes from field devices and execute control algorithms in real time. Therefore, the controller typically employs high-speed processors and optimized control algorithms to ensure real-time performance and accuracy. Reliability: The controller employs redundant design, such as redundant power supplies and redundant communication interfaces, to improve system reliability. Simultaneously, the controller also has fault detection and recovery functions, automatically switching to backup equipment or taking other recovery measures in the event of a failure. Openness: The controller supports multiple communication protocols and interface standards, facilitating integration and interoperability with other systems and equipment. This openness allows the DCS system to flexibly adapt to different industrial application scenarios and user needs. Ease of Use: The controller is typically equipped with a user-friendly interface and configuration tools, enabling engineers to easily configure, debug, and maintain the system. These tools typically offer graphical interfaces, online help, and diagnostic functions to reduce the workload for engineers and improve their efficiency. In summary, DCS controllers possess complex structures and advanced design principles, which enable DCS systems to efficiently monitor and control industrial processes, improving production efficiency, product quality, and safety. The above is a technical description of existing DCS controllers.
[0025] In a preferred embodiment, the high-temperature hot water pump 5 operates at 380V and is connected to a DCS controller, which reduces energy consumption, has a simple structure, is easy to operate, and can be connected to a DCS controller in industry to achieve overall control.
[0026] In a preferred embodiment, pressure sensors are connected to both the first and second stop valves. These pressure sensors are communicatively connected to the high-temperature hot water pump 5 and are also connected to the DCS controller for easy control.
[0027] In a preferred embodiment, a No. 3 shut-off valve is connected to both the No. 2 and No. 3 pipelines. The No. 3 shut-off valve on the No. 2 pipeline is connected in parallel to a water supply regulating valve 6 for the lower tower of the washing tower, and the No. 3 shut-off valve on the No. 3 pipeline is connected in parallel to a water supply regulating valve 3 for the upper tower of the washing tower. This allows for non-stop operation when the high-temperature hot water pump 5 is being maintained, thereby improving production efficiency.
[0028] In a preferred embodiment, the No. 3 pipeline is connected to the fifth tray of the scrubbing tower 2 to achieve scrubbing of the syngas. This method has a simple structure and is highly practical.
[0029] Finally, it should be noted that this utility model is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this utility model should be considered within the protection scope of this utility model.
Claims
1. A variable frequency automatic control system for high-pressure ash water in coal gasification, characterized in that: The system includes a gasifier (1), a scrubbing tower (2), a high-temperature hot water tank (4), and a high-temperature hot water pump (5). The gasifier (1) is connected to the middle of the scrubbing tower (2) via a No. 1 pipeline. The outlet of the middle of the scrubbing tower (2) is connected to a No. 2 pipeline. The No. 2 pipeline is divided into a No. 3 pipeline and a No. 4 pipeline. The No. 3 pipeline is connected to the upper part of the scrubbing tower (2) and a No. 1 shut-off valve is connected to the No. 3 pipeline. The No. 4 pipeline is connected to a frequency-variable high-temperature hot water pump (5) and a No. 2 shut-off valve. The No. 4 pipeline is connected to the inlet of the lower end of the high-temperature hot water tank (4).
2. The high-pressure ash water frequency conversion automatic control system for coal gasification according to claim 1, characterized in that: The high-temperature hot water pump (5) has a voltage of 380V and is connected to the DCS controller.
3. The high-pressure ash water frequency conversion automatic control system for coal gasification according to claim 1 or 2, characterized in that: Pressure sensors are connected to both the No. 1 and No. 2 stop valves. The pressure sensors are connected in communication with the high-temperature hot water pump (5) and are also connected to the DCS controller.
4. A variable frequency automatic control system for high-pressure ash water in coal gasification according to claim 1 or 2, characterized in that: The No. 2 and No. 3 pipelines are connected to the No. 3 stop valve. The No. 3 stop valve on the No. 2 pipeline is connected in parallel to the lower tower water supply regulating valve (6) of the washing tower. The No. 3 stop valve on the No. 3 pipeline is connected in parallel to the upper tower water supply regulating valve (3) of the washing tower.
5. The high-pressure ash water frequency conversion automatic control system for coal gasification according to claim 1, characterized in that: The No. 3 pipeline is connected to the fifth tray of the scrubbing tower (2) to achieve scrubbing of the syngas.