For terminal pipelines in the natural gas industry, what kind of valves are used to regulate flow?
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For terminal pipelines in the natural gas industry, what kind of valves are used to regulate flow? Natural gas provides heat to the rotary kiln, with a pressure of less than 10 KPa. Gas inlet: The gas supplier (or LNG station) provides a pressure of 0.2–0.4 MPa; an immediate-acting pressure regulator is used to maintain an outlet pressure of 10 KPa.
What you mean, OP, is that after voltage regulation, what valve is used to control the flow rate? ~~~~~The question is, what’s the difference between using butterfly valves and globe valves?
Thank you. Using butterfly valves presents the problem of inflexible regulation; previously, a three-eccentric hard-seal start control butterfly valve was used, and natural gas began to flow only after about 7% adjustment. The stop valve is used on a DN50 pipeline; its regulation range is relatively narrow, ranging from 40–60 m3/h at the lowest to 280 m3/h at the highest (under a pressure of 10 KPa). It is unstable at low flow rates.
Personally, I think it’s better to use a GLOBE valve for regulation; as for the difficulty in regulating low flow rates, it might be a problem with a certain type of valve. You can ask one or two more valve manufacturers to have their technicians do the calculations. Either the amount specified in the design has a large deviation, or the flow rate is occasionally low only under special circumstances. Or negotiate with the process team to ensure accuracy at low flow rates or accuracy at high flow rates.
https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1591047&pid=19614324&page=1&extra=page%3D1#pid19614324 Go to this post. The moderator’s advice was that, for linear regulation, a single-seat valve is definitely the better choice; if the requirements for regulation aren’t too strict, a three-eccentric valve will also work fine, as it can save a lot of money after all”
The triple eccentric mechanism is used for adjustment; it is inherently rough and has a limited range, making it suitable only for applications where high precision is not required, or where the flow rate remains constant at a certain value over time. To save costs, a triple eccentric design is chosen. Moreover, with such low pressure and a pure gas, why choose a triple-eccentric design? ? Double-eccentric soft-sealed butterfly valves are more suitable than triple-eccentric ones. For high precision, use a Globe control valve; or Fisher offers a butterfly valve with a Control Disk designed for adjustment, whose precision is similar to that of a Globe valve. Of course, the price can be set to be higher than that of domestic valves.
I also considered V-ball valves; for one project this time, a DN50 V-ball valve was chosen, with a gas flow rate that ranges from 40 to 300 Nm3/h, and the pressure is 10 KPa. A couple of days ago I contacted a manufacturer that produces V-type ball valves; they did not recommend them and suggested that I use single-seat control valves instead.
For control valves below DN200, Globe control valves are recommended unless the operating conditions are very special, as control performance should be given priority.