Thinning problem of control valves
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For the hydrogen pipeline, DN450 was selected as the process specification; it is equipped with a control valve. Based on the flow rate requirements, the valve body of this control valve is DN250, while its valve seat is DN225. By doing this diameter reduction, the hydrogen flow rate through the control valve increases, exceeding the specified value of 15 m/s. Is it appropriate to use such a control valve? Could an explosion occur due to the high flow rate?
Firstly, a high flow rate is not necessarily related to whether an explosion will occur. Secondly, the requirement regarding flow rate applies only to pipes; there is no such concept for valves – as long as it has been calculated, that’s sufficient
Indeed, flow rate and explosions are not necessarily related
Also, note that there seems to be a similar diameter change at the outlet as well: lol
This type of diameter reduction won’t work, right? Usually, two pipe grades are reduced at a time
Generally, an indentation of two levels is considered quite large. If the flow rate is too high, it may cause significant fluid noise, and it may also generate static electricity and other hazards. Therefore, flow rate and indentation need to be considered together
What was said on the 2nd floor is correct – the flow rate requirements apply only to the pipes, not to the valves. Moreover, the diameter of the valve core that you calculate is based on the process flow rate; it’s not possible to change this diameter just because the flow rate is high, otherwise it would be impossible to maintain control during production. Additionally, according to the specifications, the diameter of a valve’s reducing section is generally two sizes smaller than that of the pipeline; in other words, the diameter of the valve body should be DN350, while the diameter of the valve core is determined based on the flow rate. The valve selected in this way will be problem-free. The selection of control valves generally does not take into account the flow velocity at the valve.
By using a larger-diameter control valve, the flow rate decreases, resulting in higher costs.
Which standard requires that the hydrogen flow rate not exceed 15?
This reduction in diameter is not appropriate; the standards require a maximum of two grades, and it must not be less than half of the pipe diameter