What valves are necessary for coal chemical industry?

What valves are necessary for coal chemical industry?
Valve, the control part in the liquid conveying system, has the functions of cutting off, regulating, guiding, preventing countercurrent, stabilizing pressure, shunt or overflow pressure relief. Its varieties and specifications are quite various, it can be divided into cast iron valves, cast steel valves, stainless steel valves, dual-phase steel valves, plastic valves, non-standard customized valves, etc.

Valve, the control part in the liquid conveying system, has the functions of cutting off, regulating, guiding, preventing countercurrent, stabilizing pressure, shunt or overflow pressure relief. Its varieties and specifications are quite various, it can be divided into cast iron valves, cast steel valves, stainless steel valves, dual-phase steel valves, plastic valves, non-standard customized valves, etc.
Four key points for a smooth valve installation
Construction work
Many valves are directional, such as globe valves, throttle valves, pressure relief valves, check valves, etc. A little careless, installation direction is reversed, the consequences are not the same:
(1) The direction of throttle valve is reversed, which directly affects the use effect and life.
(2) Pressure reducing valve direction is reversed, does not work at all.
(3) Check valve direction is reversed, high risk probability.
Under normal circumstances, the valve body will be marked with direction. If not marked, remember to correctly identify the installation according to the working principle of the valve.
Globe valve, valve chamber left and right asymmetry, should keep the fluid flow from down to up through the valve port, so that the fluid resistance is small, open labor-saving, closed media without pressure packing, easy maintenance.
Valve installation position must be easy to operate. Even if the installation is a little difficult, also want to think about the future long-term work. It is better to keep the valve handwheel aligned with the chest, and save effort to open and close the valve. Ground valve handwheel should be up, can not tilt, so as not to operate smoothly. The valve of the machine against the wall should have room for the operator to stand.
Do not cut the pressure reducing valve oblique installation, otherwise it is not conducive to normal use.
Prohibit lifting check valve disc cutting oblique, otherwise the lifting is not flexible, affecting the normal use.
It is forbidden to install the stem gate valve underground, otherwise the exposed stem will be corroded due to long-term damp underground.
Prohibit valve handwheel downward direction, otherwise it will make the medium retained in the bonnet space for a long time, easy to corrode the stem, and it is not convenient to replace the packing.
Four key points for a smooth valve installation
Construction work
Four key points for a smooth valve installation
Installation construction must be careful, do not hit the brittle material made of the valve.
Before installation, carefully check that all valve types and specifications meet design requirements and check that packing is intact. Is there sufficient adjustment allowance for gland bolts? Also pay attention to whether the stem and disc are stuck and skewed?
Check whether the valve model and specification meet the design requirements, according to the valve model and factory manual, check whether they can be used under the required conditions, if necessary for water pressure or pressure test.
The sealing surface of the valve disc must be closed tightly, and the quality of the threaded valve should be checked.
During installation, do not tie the rope to the handwheel or stem to avoid damaging these parts, tie it to the flange. For valves connected to the pipeline, be sure to clean.
When installing the screw valve, the sealing packing should be wrapped in the pipe thread, do not get into the valve, resulting in the valve memory product, affecting the flow of media.
When installing flanged valves, valves and flanged pipes should be kept parallel and the gap is reasonable to avoid excessive pressure or even cracking of valves.
Four key points for a smooth valve installation
Protection measures
Some valves also require external protection, i.e. insulation and cooling. Sometimes a hot steam line is added to the insulation layer. What kind of valve should be insulated or cold, according to the production requirements.
In principle, the medium in the valve to reduce the temperature too much, will affect the production efficiency or frozen valve, you need to heat preservation, even heat. When the valve is exposed, adverse to production or cause frost and other undesirable phenomena, it is necessary to protect cold.
Four key points for a smooth valve installation
Packing replacement
Stock valves, some packing failure due to a long time, or inconsistent with the use of media, you need to replace the packing.
When replacing the filler, press it in a circle. Ensure that the joints of each ring are 45 degrees appropriate, and the ring and ring are connected 180 degrees.
The height of packing should consider the room for further compression of the gland. At present, the lower part of the gland should be pressed to an appropriate depth of the packing chamber, which can generally be 10-20% of the total depth of the packing chamber.
For demanding valves, seam Angle is 30 degrees. The joints between the rings are staggered by 120 degrees.
Which valve is the coal chemical industry valve?
The valve used in coal chemical plant should be multi-faceted.
The off-line desulphurization system should take into account adaptive temperature and corrosion as well as seal leakage standards. Butterfly valves, ball valves and gate valves are commonly used.
Material conveying system will use pneumatic knife gate valve, gate valve, powder ** butterfly valve, V-ball valve, ceramic valve, spiral conveying valve also take into account the wear resistance of the valve.
Common water refill system common soft seal butterfly valve can. Ammonia ammonia is relatively low standard use stainless steel 304 material ball valve, small diameter with three-piece ball valve, large diameter with flange connection of two-piece ball valve, sealing is good.
Chemical valve and coal chemical project valve
Chemical valve is an important accessory of fluid control in industrial pipeline. Facing the various working conditions of complex industrial system and wide variety of valves, we want to choose suitable chemical valve for pipeline system.
Chemical valve overview:
Chemical valve is a kind of important industrial pipeline flow control on the attachment, in the face of a great variety of all kinds of complicated industrial system and valve working condition, want to choose suitable valves, pipeline system and understand the performance of the valve, the second should master valve steps and basis of the three should follow the principle of choosing valves for petroleum, chemical industry.
Chemical valves are not only applicable to a wide range of applications, but also more dosage, of course, chemical valves are higher than the requirements of ordinary valves. Chemical valves generally use medium are relatively easy to corrosion, simple chlor-alkali industry, to large petrochemical enterprises, there are high temperature, high pressure, corrosion resistance, wear resistance, temperature and pressure difference is very large. In the face of this high risk valve, in the selection and use of the process should be strictly in accordance with the chemical standards.
Selection principle of chemical valve:
Chemical industry generally choose port for straight through the valve, the flow resistance is small, usually choose as a globe valve and open media use, easy to adjust flow valve as a control flow, plug valve and ball valve is suitable for reversing shunt, shut down along the sealing surface of sliding valve with wiping * * is suitable for the medium with suspended particles. Common chemical valves have ball valves, gate valves, globe valves, safety valves, plug valves, check valves and so on. Chemical valve medium mainstream with chemical substances, containing acid and alkali corrosion media, in terms of material dominant 304L and 316, common media should also choose 304 as the leading material, a variety of chemical substances combined with the corrosion fluid should choose alloy steel or fluorine lined valve.
The role of chemical valve:
Opening and closing action: cut off or communicate the flow of fluid in the pipe;
Regulating effect: regulating the flow rate and flow rate in the tube;
Throttling effect: the fluid through the valve after a large pressure drop;
Other functions: a. open and close automatically b. maintain a certain pressure C. prevent steam drainage.
Precautions before using chemical valves:
(1) Whether the inner and outer surface of the valve body has trachoma, cracks and other defects;
(2) valve seat and valve body joint is firm, spool and valve seat is consistent, sealing surface has no defects;
(3) whether the stem and spool connection is flexible and reliable, whether the stem is bent, whether the thread is damaged;
④ Whether the valve is open flexibly, etc.
Chemical valves in the process of use often appear problems
1. Flange and thread leakage at the connection with the pipeline;
2, packing culvert leakage, waist pad leakage and stem open not to move;
3, the valve core and valve seat is not tightly closed to form internal leakage