Calculations related to the gas supply pipeline system
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We have a project that uses valve island boxes, and some of the valves are located 50 meters away. The client has asked us to prepare detailed calculations for parameters such as gas consumption, valve opening and closing times, and gas supply pressure. In particular, we need to calculate these parameters when multiple valves operate simultaneously. Everyone I’ve asked says they have never done such calculations before; I would like to ask my colleagues here – has anyone encountered this situation before?
Generally, there is a gas source storage tank; the volume is calculated according to specified standards, and this capacity is definitely sufficient
The standards related to gas consumption provide estimated values for the usage amount of individual control valves, individual on/off valves, and other gas supply devices; refer to the Instrument Gas Supply Design Specification HGT20510
I only see control valves and other gas-related instruments; there are no on/off valves, right?
Each building is equipped with a gas storage tank, which is provided by the piping team; the calculation method used differs from that specified in the instrumentation standards. Moreover, the frequency of valve operation in this project is not clear to begin with, and it is likely to be low, while the number of valves that operate at any given time is also uncertain
It was proposed for calculation because the gas supply pipe has been extended, and they want to know the delay time
The air consumption and shutdown time need to be calculated by the design institute; especially for parameters related to multiple valve operations, have you done the calculations on your end?
If the valve has a model number, the specific gas consumption parameters can be requested from the manufacturer; if not, estimates from the instrument air design can be used
The gas consumption is calculated based on experience: the locator requires 0.35–0.65 Nm3/h, while the shut-off valve needs 1.0 Nm3/h. The leakage coefficient for the gas supply network is 0.1–0.15. A distance of 50 meters isn’t a problem. I will ask the manufacturer for the gas consumption parameters for the valves in this area; the opening and closing times should be determined by the process team. As for the gas supply pressure, it depends on the specifications outlined in the instrument design. When multiple valves operate simultaneously, only approximate estimates can be made based on these factors.
The valve closing time is specified in the instrument specification sheet, which sets clear requirements for it； Pressure and gas consumption are provided when submitting requests for funding to the process piping department; these are all part of standard design practices.