Why do P4 valves tend to fail?
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Our factory uses a full-circulation water solution process. We would like to understand why the pressure control valve at the outlet of the urea synthesis tower (i.e., valve P4) tends to fail so frequently, thereby affecting normal operations. How can this be controlled during production in order to reduce the likelihood of failures and extend the service life of valve P4?
Could you be more specific? The P4 valve is indeed the most important valve in urea production, and the high likelihood of failures is closely related to its harsh operating conditions: high temperatures, large pressure differences, strong corrosion, and severe erosion. However, I think the original poster should provide more detailed information on exactly what’s going wrong – whether it’s a problem with the valve itself or with the instrumentation. It is also recommended to carefully select manufacturers and conduct regular inspections
As the temperature drops, the likelihood of P4 valve failures **increases**. A special note: I have encountered this issue several times during my shifts. Factors such as purity, pump settings, the ratio of components in the mixture, and insulation can lead to problems with the valve’s operation, resulting in overpressure in the synthesis tower; in such cases, it is necessary to use a handwheel to control the pressure promptly.
The main issue was an excessive pressure difference before and after the P4 valve; however, we have resolved this problem completely. The device has been in use for over a year now, and we have also obtained a **patent** for it.
Could we talk about how you manage to keep it working for over a year, since our average usage period is only around 3 months.
:Handshake: It is common for safety incidents to occur in the urea synthesis tower due to failures in P4, which can even lead to the shutdown of the entire system. In my personal opinion, it is essential first to ensure that the materials used for the valve core and valve body are urea-grade stainless steel. Secondly, it is necessary to ensure the proper operation of the instrument control components, such as the pressure of the gas supply, the lubrication of valve packing, as well as the maintenance and replacement of diaphragms. :handshake :handshake
In addition to the material requirements for the P4 valve needing to be met, and it being preferable to use materials such as A4 steel or 316L MOD, it is also important to ensure that its nominal dimensions are appropriate and not too small. The valve head of the P4 valve needs to be modified to some extent. The modification method is a patent!