Besides some general-purpose valves used in some coal chemical industry conditions, dedicated valves for the coal chemical industry are as the following:
Metal hard sealed wear resistant ball valves, including lock hopper valves, air release valves and balance valves
Black water control valves, gray water control valves and high pressure difference control valves
Balance valves and slag valves at high temperatures
Pulverized coal regulating valves and pulverized coal three-way reversing valves
Pulverized coal switch valves, coal-water slurry stop valves, oil-coal slurry stop valves and gray water eccentric valves
Oxygen valves and dedicated ball valves for oxygen
Pneumatic hard sealed ball valves
Orbital ball valves
Slide valves and air release regulating valves
Pulse cleaning valves (reverse valves) and dedicated cleaning valves for ash removal filters
Pneumatic eccentric spherical control valves
In order to meet the need for China’s energy structure adjustments, the research and development of large-scale coal chemical equipment is listed as one of the 16 major technical equipment tasks that China develops well. The domestication of large-scale coal chemical equipment is also the focus in the future. The rapid development of the large-scale coal chemical industry requires the support of corresponding technical equipment, especially coal-to-liquid, methanol, synthetic ammonia and coal-to-olefin and other coal chemical industries that require a great amount of large-scale coal chemical equipment. The domestication of related technical equipment is an important measure to reduce project investment, save foreign exchange and improve industrial competitiveness. The main research and development projects of large-scale coal chemical industry equipment include extra large hydrogenation reactors, centrifugal pumps and positive displacement pumps for coal liquefaction, dedicated valves for coal liquefaction, coal-oil slurry heating furnaces, large-scale coal slurry homogenization stirrers, large thrust reciprocating compressors and large centrifugal compressors, special waste heat boilers, large coal preparation equipment, oil residue gasification core equipment and large natural gas hydrogen pstemuction core equipment.
1. Coal chemical ball valves
The ball valve can be rotated at 90 degrees, and the cock body is a sphere, with a circular through hole or channel passing through its axis. The ball valve is mainly used to cut off, distribute and change the flow direction of the medium in the pipeline. Only rotating 90 degrees and a small torque are required to tightly close the valve. The ball valve is most suitable for using as a opening and closing or shut-off valve, but recent development has designed the ball valve to throttle and control flows.
2. Coal chemical gate valves
The plate of the gate valve moves linearly along with the valve stem, which is called a rising stem gate valve. Usually there is a trapezoidal thread on the lifting stem. Through the nut on the top of the valve and the guide groove on the valve body, the rotary motion is changed into the linear motion, that is, the operating torque is turned into operating thrust. When the valve is opened and the lift height of the plate is equal to 1 time of the valve diameter, the fluid channel is completely unblocked. However, this position cannot be monitored during operation. In actual use, the apex of the valve stem is used as a mark, that is, the position which cannot be opened is regarded as the fully open position.
3. Coal chemical butterfly valves
The opening and closing part of a butterfly valve is a butterfly plate with a disc shape, which rotates around its own axis in the valve body so that the valve can be opened, closed or adjusted. The butterfly valve is usually fully opened to fully closed by turning less than 90 degrees. The butterfly valve and its stems are not self-locking. For the positioning of the butterfly plate, a worm gear reducer must be installed on the valve stem. The use of worm gear reducer can not only make the butterfly plate have self-locking ability, making the butterfly plate stop at any position, but also improve the operation performance of the valve.
4. Coal chemical globe valves
The opening and closing part of the globe valve is a disc shaped like a plug. The sealing surface is flat or conical, and the disc moves linearly along the centerline of the fluid. The movement forms of valve stems include a lifting stem type and a lifting rotating stem type. The valve stem is raised and lowered, while the hand wheel does not rise. The hand wheel and valve stem rotate and rise together, and the nut is set on the valve body. The globe valve is only suitable for being fully opened and closed, and adjustment as well as throttling are not allowed. The globe valve is a forced sealing valve, so when the valve is closed, pressure must be applied to the disc to force the sealing surface in order to not leak.
5. Coal chemical check valves
According to the structure of the check valve, it can be divided into three types: lift check valves, swing check valves and butterfly check valves. Lift check valves can be classified into two types: vertical and horizontal types. Swing check valves are divided into three types: single disc valves, double disc valves and multi disc valves. The butterfly check valve is a straight-through type. The above-mentioned check valves can be connected by threads, flanges and welding. The large check valve should be independently supported so that it will not affected by the pressure generated by the piping system.
6. Coal chemical safety valves
The safety valve is an automatic pressure relief protection device which is opened by the inlet static pressure. It is one of the most important safety accessories of pressure vessels. Its function is that when the pressure in the vessel exceeds a certain value, the valve is opened automatically, depending on the pressure of the medium itself to quickly discharge certain quantity of media. When the pressure in the container drops to the allowable value and the valve automatically closes, so that the pressure in the container is always lower than the upper limit of the allowable pressure, and automatically prevents accidents that may occur due to overpressure. Therefore, the safety valve is also called the ultimate protective device for the pressure vessel.
7. Coal chemical pressure reducing valves
The pressure reducing valve adjusts the flow of the medium by controlling the opening of opening and closing parts in the valve body to reduce the pressure of media. At the same time, the opening of opening and closing parts is adjusted by the pressure behind the valve to keep the pressure behind the valve within a certain range. Cooling water is sprayed into the valve body or behind the valve to reduce the temperature of the medium. This kind of valve is called a pressure reducing valve. The pressure reducing valve can be divided into the diaphragm type, spring diaphragm type, piston type, lever type and bellows type according to the structure.
8. Coal chemical solenoid valves
A solenoid valve is an automatic basic component used to control fluids, which belongs to actuators. It is not limited to hydraulic and pneumatic types. Solenoid valves are used to control the direction of hydraulic flows. Factory machinery is generally controlled by hydraulic steel, so solenoid valves are used. The solenoid valve has a closed cavity. There are through holes at different positions. Each hole leads to a different pipe. The valve is in the middle of the cavity, and on both sides are two electromagnets. Once the power is switched on for a side of magnet coil, the valve body will be drawn to the magnet coil. Control the movement of the valve body to block different oil discharge holes, and the oil inlet hole is normally opened. The hydraulic oil will enter the different oil discharge pipes, and then push the piston of the oil through the oil pressure. The piston drives the piston stem, and the piston stem drives the mechanical device to move. In this way, the mechanical movement is controlled by controlling the current of the electromagnet.
9. Coal chemical regulating valves
Regulating valves are used to adjust process parameters such as medium flow, pressure, temperature and liquid level in the field of industrial automation process control. According to the control signal in the automation system, the opening of the valve is automatically adjusted to realize the adjustment of the medium flow, pressure, temperature and liquid level. The regulating valve is usually composed of two parts such as an electric actuator or a pneumatic actuator and a valve body. There are two types of straight strokes: straight single seater and straight two seaters. The latter has the characteristics of large flow capacity, small imbalance and stable operation, so it is usually especially suitable for occasions with large flows, high pressure drops and little leakage. The angular stroke mainly includes V-type electric regulating ball valves, electric butterfly valves, ventilation regulating valves and eccentric butterfly valves.
