Can the styrene sampling cylinder be online for a long time?
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This post was last edited by cust008 on 2022-7-21 10:53 We want to implement sealed sampling of styrene, but we have not found any information on sealed sampling of styrene. At the same time, after each sampling, the styrene in the sampling pipeline must be drained and processed, which is really troublesome. Can the sampling cylinder be kept online for a long time, and the next time sampling is done, the cylinder can be removed directly and replaced with a new one? The purpose of this thinking is to always maintain the flow in the sampling pipeline and eliminate the discharge and post-processing of styrene in the sampling pipeline.
Probably not. It should be fine without keeping it flowing
This post was last edited by qugd on 2022-7-21 12:26. It’s totally fine. Make two identical bypasses on the sampling pipeline and connect the two sampling cylinders. Normally, the sampling cylinder is used as part of the bypass pipeline. When sampling regularly, close the outlet of the sampling cylinder. When the sampling volume is reached, close the entrance of the sampling cylinder. ； At the same time, open all valves in the other bypass to keep the sample flowing in the other bypass. Close the valve of the circuit you were sampling just now, remove the cylinder filled with samples, and send it to the laboratory. At the next sampling time, bring back the cylinder that was disconnected, connect the cylinder to the bypass, and open the bypass and valve. ； Just fill the other cylinder with sample according to the sampling procedure. Refer to the figure below. The capacity of the cylinder is determined according to the required sample volume. The larger the cylinder, the better the representativeness. In this way, a representative sample is obtained without wasting a large amount of sample by emptying it.
I'd like to do only one sampling route if that's feasible, I'm worried about aggregate congestion if the other route is closed. This flow of fluid is maintained at all times, with only a brief pause when the sample cylinder is replaced. In addition, whether the gas in the sampling bottle needs to be considered, firstly, whether nitrogen replacement is needed (not that oxygen in the air is useful for preventing polymerization), and secondly, whether a pipeline needs to be connected to discharge these gases when replacing the sampling bottle to prevent it from entering the styrene system.
This post was last edited by qugd on 2022-7-21 13:54. The position of the sampling cylinder can be replaced by a section of steel pipe, so that there will be no stagnant flow. This is so simple and practical. Just design a vent valve downstream of the sampling cylinder to vent the dead volume that may contain oxygen. Is it from Jieyang Petrochemical? If so, how about asking the many experienced old masters and senior leaders of Daqing Petrochemical Company directly for advice?
There is no need for the sampling cylinder to be online for a long time. It is enough to set a bypass on the pipeline where the cylinder is installed to keep the flow flowing. The solution of using a section of steel pipe to replace the 5# building is also acceptable. The advantage of setting up a bypass is that there is no need to replace the section of steel pipe every time the cylinder is sampled, and there is no need to collect a small amount of styrene liquid in a portable bucket, which is safer and more environmentally friendly.