The top-entry lock hopper slag valve is a key valve specially designed for lock hopper systems in industries such as coal chemical industry and metallurgy. It is mainly used to control the on-off of media containing solid particles (such as coal slag and slag), and features wear resistance and easy maintenance. The following is an introduction to its core information:
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Top-entry design: The valve body and valve cover adopt a separate structure. Internal components such as the valve core and valve seat can be directly disassembled and replaced from the upper part of the valve body without removing the entire valve from the pipeline. This greatly reduces the shutdown maintenance time, and is especially suitable for scenarios where frequent disassembly and assembly are difficult, such as lock hopper systems.
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Wear-resistant internal parts: The valve core and valve seat are mostly made of wear-resistant materials such as high-chromium cast iron, duplex steel or ceramics. Their surfaces are hardened (such as surfacing with wear-resistant alloys), which can withstand the erosion of high-concentration particle media and prolong the service life.
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Sealing structure: Metal hard seals or elastic seals (such as wear-resistant rubber) are adopted. Some models are designed with purge ports, through which nitrogen or steam can be introduced to clean the particles attached to the sealing surface, ensuring reliable sealing and reducing leakage.
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Drive mode: Pneumatic or hydraulic drives are common, with large output torque, which can quickly realize opening and closing actions (generally, the full opening/closing time is ≤3 seconds), adapting to the working condition requirements of periodic slag discharge in lock hopper systems.
The lock hopper system is the core link for slag discharge of coal chemical gasifiers. The lock hopper slag valve completes the slag discharge cycle by cutting off or connecting the path between the lock hopper and the downstream pipeline, cooperating with the system pressure change:
- When the slag in the lock hopper accumulates to a certain amount, the valve closes, and the lock hopper is pressurized;
- When the set pressure is reached, the valve opens, and the slag is discharged under the action of pressure difference;
- After the slag discharge is completed, the valve closes again, and the lock hopper is depressurized, entering the next cycle.
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Coal chemical industry: Mainly used in the lock hopper slag discharge systems of coal water slurry gasification and pulverized coal gasification devices, such as space furnaces and GE gasifiers, to control the on-off of high-temperature (usually ≤250℃) and high-pressure (up to 6.4MPa or more) slag-containing black water.
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Metallurgical industry: In the lock hopper systems for blast furnace slag and steel slag treatment, it is used to transport high-temperature slurry containing solid particles.
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Environmental protection industry: Some ash and slag treatment systems of waste incineration power generation projects also adopt it, which is suitable for slag media containing corrosive components.
- The matching wear-resistant materials and sealing forms should be selected according to the particle size, concentration, temperature and pressure of the medium;
- Priority should be given to models with purge function to reduce the wear of particles on the sealing surface;
- The drive mode needs to meet the system response speed requirements. Pneumatic drive is suitable for medium and low pressure scenarios, while hydraulic drive is more suitable for high-pressure and large-diameter (DN300 and above) working conditions.
The core requirements of such valves are wear resistance, quick opening and closing, and reliable sealing. Moreover, the top-entry structure significantly reduces the maintenance difficulty, making it a key equipment for the stable operation of the lock hopper system.
