System commissioning failure caused by a mistake in volume units when selecting flow control valves together
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This post was last edited by we11we11 on 2021-7-18 at 10:33. In 2017, a project abroad came online, and its natural gas condensate transfer system was put into operation; multi-stage centrifugal pumps were needed to transport the condensate to a degassing station for recovery. All the necessary tests and preparations before startup were completed. After starting the centrifugal pumps, it was found that there was pressure buildup at the pump outlet, and the flow rate indicated by the flow meter on the outlet pipeline was far below the rated value. After several checks, it was determined that no flow was occurring in the pipeline, likely due to some blockage somewhere in it. So, all the valves involved in the pipeline were taken apart one by one for inspection, and it was discovered that the valve core of the flow control valve on the pipeline was actually only as small as a pinhole. Everyone was shocked – how could the condensate get through? So I went back to check the manufacturer’s calculation instructions and the flow rate parameters provided by the design institute, and discovered a huge mistake in the units used for flow rate: the manufacturer calculated using m3/h as if it were kg/h. No wonder a valve core that should have been the size of a bowl opening ended up being as small as a pinhole, resulting in such an absurd malfunction. It seems that thorough examination of the manufacturer’s documents during the project design phase is truly essential; there’s no room for any carelessness.
It seems that the supervisor for on-site installation is just that – there’s no need to discuss it further. It seems inappropriate that there is no process supervision from the client on site. It might be due to the project being too large and too formalistic. It must be difficult for the installers as well; it’s unclear how this flow meter was installed into the process. It’s strange; I can’t figure out the range of compatibility between the flow rate being measured and the pipe diameter. P
1. This project didn’t have a supervisor; the owner was a world-renowned oil company. It’s unclear why this approach was chosen. 2. Essentially, the owner hardly ever got involved in this project – they would just come to the site once a day and then leave. The final inspection also focused mainly on the documents. 3. The inlet and outlet dimensions of the valve remained unchanged; only the diameter of the valve stem changed. As a result, the valve could still be installed, and it was difficult to identify any problems. It took a lot of effort to disassemble the valve in order to see the valve stem, and everyone was surprised by what they saw. Perhaps it was because this was such a large project that, in an attempt to save money, very few people were employed, and the deadline was extremely tight: lol
Did the design team fail to conduct proper checks when the manufacturer returned the calculation documents? Wasn’t the inspection upon unboxing carried out by referring to the specification sheet?
The prices of control valves with capacities of 15 kg/h and 15 m3/h must also differ significantly, right? Doesn’t anyone think those quotes are unusual?
It’s a too-large project; this valve is just very small, so it wasn’t taken into account in the design. There are too many equipment items on site, and it’s simply impossible to check it during inspection
It’s fine no matter what you say if there are no problems.