Regarding the installation of safety valves and rupture discs
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Our company has a new chemical plant in Jiangxi, and we commissioned a design firm based in Nanchang, Jiangxi (a branch of Jiangsu Zhongjian) to carry out the chemical engineering design for us. On the PID diagrams, designs for rupture discs, safety valves, and flame arrestors were included for all reactors and tanks. However, only two of our reactors generate gas; the rest are at atmospheric pressure, and some of them even operate in a aqueous medium. Yet these devices were installed without any consideration for such differences. I asked them why they included them, and they replied that it was a precautionary measure – that they were necessary. I think they are overreacting; designing in such an indiscriminate manner, without taking into account the actual operational conditions, is irresponsible. Moreover, atmospheric pressure reactors are connected to heat exchangers, and their exhaust gases are routed into the main exhaust system of the workshop. I’m not sure what your thoughts are on such a design.
I’m not sure what your specific medium is; I’m not clear what is meant by an aqueous system or a low-temperature system. If it’s really as you say and there’s no possibility of overpressure, then safety valves are unnecessary. My advice is to check the basis for his design – the national standards, ministry-issued standards, and industry standards referenced in the drawings. Until things are clarified, it’s better to avoid using any accusatory language. Once it’s proven to be reasonable, do you still need to say “I’m sorry”? :lol
It is reasonable to design the reflux system in this way; overpressure can occur, especially in low-temperature systems such as washing and extraction, as well as freeze crystallization (using solvents like methanol and toluene). Moreover, a condenser and an exhaust gas manifold are connected to the reactor – would it not be redundant to install an additional safety valve? In water-based systems, processes such as washing and extraction, acid hydrolysis and neutralization take place, with the maximum temperature reaching only 60–70 °C. Strangely enough, the intermediate transition tank is also designed in this manner, rather than being equipped with a vent valve or something similar
If you are the client, you should put these matters in writing, have them stamped by the relevant departments of your company, and send a letter to the other party requesting a design change. For such matters, it is necessary to follow established procedures. Discussing them here without proper processes and technical requirements makes technical discussions pointless, like trying to solve riddles – it is inefficient. For reference.
Yes, the core of the issue is that the old man in charge trusts the design institute; we think it’s unnecessary, so we came to ask the experts at Haichuan for their opinions on this type of design: lol
Beyond the normal aspects, there are also unusual tricks and schemes involved in such things. Everyone should take responsibility for their own actions; if one insists on upholding principles, they must have solid reasons for doing so and also consider possible alternatives. There are things whose value needs to be assessed; if your solution can save over a hundred thousand in costs, you should pursue it in order to put an end to the problem right away. If it’s a team of entrepreneurs, it’s best not to interfere. I just need to know what’s going on, after all, it’s to earn a living. It is not advisable to lose one’s job.
As long as it’s not a design firm with extremely poor capabilities, they won’t implement such features unless necessary; after all, it increases their workload (such as calculating discharge rates and selecting safety valves). Moreover, if there is no basis for implementing these features or the basis is insufficient, people will say that the firm’s competence is inadequate. LZ can communicate with the designers and ask them to explain the basis and necessity of the settings.
There is a reason for everything; as long as they don’t simply copy what exists, designers will follow the relevant regulations and standards