The variable control valves used in hydrogen production PSA systems (West China Hospital in Chengdu), such as check valves, have a valve-opening/closing speed that is determined based on measurements...
Thread Content
For the hydrogen production PSA units (Chengdu West China), throttling valves such as check valves – is the speed at which these valves open and close determined by the measured pressure, or is it set by the manufacturer’s technicians from the beginning?
In automatic mode, the measured pressure as well as the PID parameters of the control valve are adjusted! Manually, according to the upper and lower limits of the follow-up control valve!
The manufacturer’s staff sets the automatic valve parameters based on the desorption efficiency
Oh, once the PID parameters are set by the manufacturer, they generally don’t change, right? For programmable valves like the Yun type, the PID setting generally doesn’t need to be adjusted either, right?
It always seems that the pressure is a bit low after our forward flow process ends. If we adjust the pressure setting at the end of the forward flow process as well as the initial opening degree of the flushing valve, are there any upper and lower limits for these adjustments, or is it determined based on actual conditions? The initial opening degree of our flushing valve is currently 29; the pressure set at the end of the discharge process is 0.28 MPA. At present, the hydrogen production rate is around 17,000, with a full-load capacity of 30,000
Programmable valves are fully open or fully closed; only follow-up valves have such functionality!
The level of pressure at the end of the purge is determined by two factors: 1) the purity of the product hydrogen (the higher the purity requirement, the lower the pressure at the end of the purge), 2) the amount of purge gas used (the greater the amount of purge gas, the lower the pressure at the end of the purge). The pressure at the end of forward feeding, at 0.28 MPa, is not low; in fact, it’s considered a bit high. Moreover, there is no absolute relationship between the pressure at the end of forward feeding and the load.
As mentioned above, the level of backpressure is mainly determined by purity, the control of the purge gas flow rate, and the process flow. By the process I’m referring to, I mean that for example, some are placed sequentially after the second average value and before the third average value; the pressure in such cases is already higher when they are placed sequentially, and it remains high even after the placement is completed ； In some cases, the sequential discharge is arranged after the three equalizations; the pressure in the sequential discharge tank is low, and it remains relatively low even after the sequential discharge is completed.