Eccentric Half Ball Valve in Coal-Water Slurry Working Conditions
Coal water slurry is a new type of clean liquid fuel and an important part of clean coal technology. Since its inception, it has been favored for its many advantages such as oil replacement, energy saving, high-efficiency combustion, and low pollution. However, coal-water slurry has the characteristics of strong corrosion, strong erosion, and high particle hardness before and after manufacture.
Because of the harsh working conditions of the coal-water slurry system, most of the valves used in the coal-water slurry system are ball valves. According to the requirements for working conditions and reducing the operating cost of customers, the eccentric half ball valve used in the working condition of the pipeline conveying coal-water slurry system has been developed.
Structural Features
According to the working conditions of coal-water slurry, the new metal-seated eccentric half ball valve suitable for corrosive and high-hardness working conditions has many characteristics.
Because of the harsh working conditions of the coal-water slurry system, most of the valves used in the coal-water slurry system are ball valves. According to the requirements for working conditions and reducing the operating cost of customers, the eccentric half ball valve used in the working condition of the pipeline conveying coal-water slurry system has been developed.
Structural Features
According to the working conditions of coal-water slurry, the new metal-seated eccentric half ball valve suitable for corrosive and high-hardness working conditions has many characteristics.
(1) Corrosion resistance: it can meet the special requirements for petrochemical industry on corrosion.
(2) The sealing performance is reliable.
(3) Easy to clean: when the system is overhauled, the coal slurry medium staying in the valves and pipelines is very easy to deposit coal particles, which will cause the valves to fail to open normally. Therefore, a cleaning port and a sewage discharge port are provided on the valve body. This structural design plays a vital role in flushing the valve and preventing the valve from being stuck.
(4) Erosion resistance: the cobalt-based alloy with good corrosion resistance, high-temperature resistance and wear resistance is welded on the sealing pair. High wear-resistant WC is sprayed on the flow surface of the valve cavity, so that the hardness of the sealing pair and the flow surface of the valve are greater than and equal to 65HRC, and the valve has better wear resistance and erosion resistance.
Pairing and Processing Technology of Sealing Surface Materials
The pairing selection of the sealing material is directly related to the performance and service life of the valve. According to the machining process and heat treatment conditions, it is ideal to choose the form of spraying WC on the surface of the valve disc and surfacing welding of Stellite alloy on the sealing surface of the valve seat. This pairing can realize that the hardness of the sealing surface of the valve disc is greater than that of the valve seat, which can meet the requirements for high temperature, high pressure and frequent opening. Since the surfacing welding Stellite on the sealing surface of the valve seat is thicker, the anti-seizing performance is better.
Compared with the ball valve, the sealing, economic and energy saving and consumption reduction performance of the eccentric hemispherical valve have become very prominent. Its advantages include compact overall structure, online maintenance, good sealing performance between disc and seat, high sealing pressure, small wear between sealing surfaces, long service life, flexible movement of pneumatic or electric actuators, easy remote control and automation and reliable work, greatly reducing the labor intensity on site.
(3) Easy to clean: when the system is overhauled, the coal slurry medium staying in the valves and pipelines is very easy to deposit coal particles, which will cause the valves to fail to open normally. Therefore, a cleaning port and a sewage discharge port are provided on the valve body. This structural design plays a vital role in flushing the valve and preventing the valve from being stuck.
(4) Erosion resistance: the cobalt-based alloy with good corrosion resistance, high-temperature resistance and wear resistance is welded on the sealing pair. High wear-resistant WC is sprayed on the flow surface of the valve cavity, so that the hardness of the sealing pair and the flow surface of the valve are greater than and equal to 65HRC, and the valve has better wear resistance and erosion resistance.
Pairing and Processing Technology of Sealing Surface Materials
The pairing selection of the sealing material is directly related to the performance and service life of the valve. According to the machining process and heat treatment conditions, it is ideal to choose the form of spraying WC on the surface of the valve disc and surfacing welding of Stellite alloy on the sealing surface of the valve seat. This pairing can realize that the hardness of the sealing surface of the valve disc is greater than that of the valve seat, which can meet the requirements for high temperature, high pressure and frequent opening. Since the surfacing welding Stellite on the sealing surface of the valve seat is thicker, the anti-seizing performance is better.
Compared with the ball valve, the sealing, economic and energy saving and consumption reduction performance of the eccentric hemispherical valve have become very prominent. Its advantages include compact overall structure, online maintenance, good sealing performance between disc and seat, high sealing pressure, small wear between sealing surfaces, long service life, flexible movement of pneumatic or electric actuators, easy remote control and automation and reliable work, greatly reducing the labor intensity on site.
