Measurement schemes for the condensation return flow rate in certain reaction vessels equipped with a condensation return system
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Certain reaction vessels equipped with a condensation reflux system are common chemical processing equipment used in actual industrial chemical production. Such a condensation reflux system typically includes a condenser, a condensate separator (such as an oil-water separator), and the associated piping systems. A sight glass is generally installed on the reflux pipeline to allow operators to manually monitor the condition of the reflux process. The flow rate of the condensed reflux liquid is an important process variable that changes during the production process in such reactors. It reflects the intensity of the reaction at a particular stage, as well as whether the heating temperature profile of the reactor is correct and appropriate. Therefore, the indicator of the reflux liquid flow rate is of great significance for determining an appropriate heating temperature profile, improving the quality of process control in the reactor, and enhancing its production efficiency. In fact, technical personnel from resin manufacturers have suggested that if it were possible to measure this reflux flow rate directly and automatically online, it might make it possible to achieve an automatic control system for the reactor’s temperature profile that operates on a \"one-click, user-friendly\" basis. In my opinion, even without those high-standard requirements, real-time data on the reflux volume is still something that everyone needs. Therefore, an effective and reliable automatic monitoring device for the reflux volume of condensate in reaction vessels is indeed necessary, as it is truly useful. Well, this is nonsense here. Some might say, isn’t it just a simple measurement of liquid flow? There are so many different types of flow meters available on the market; choosing the right one should be a trivial task in no time at all. Is it that difficult? The trick is, there really are! (To be continued)
(Continuing from above) First of all, the space available at the equipment installation site for installing the return pipes may leave very limited headroom, which results in a very low return flow rate； Secondly, the flow rate varies greatly throughout the different stages of the reaction. If a low flow rate is desired along with a high volume of flow, then the pipe diameter cannot be too small. You cannot change this pipe diameter at will – trying to reduce it is not an option ； Thirdly, if certain components in the reflux liquid form precipitates at low temperatures and tend to stick to the pipes, could this affect the accuracy of your instrument measurements? Is it good to use an electromagnetic flowmeter? But what if the condensation reflux liquid has low electrical conductivity? Answer: Reject ； What if it has good electrical conductivity then? Can we still pretend not to know about the full pipe requirement? Well then, let’s arrange the pipes with the pipeline filled to capacity; how about raising the outlet? But you must not affect the operational functionality of the separator ahead; otherwise, you will be told that the consequences will be severe. Would a rotameter work? Not to mention the impact on the flow cross-section, that poor pressure difference and flow rate – are you really sure you’d dare to use it? As for other types such as target-type, worm-gear type, Anuba type, rotor-type, etc., it’s probably best to forget about them. Finally, the high-end mass flow meter – could it solve the problem? But for that Coriolis force measurement, the complex internal piping structure is required – so how can scale buildup on the inner walls of those pipes be removed? Users have already tried it, and whether the psychological pain caused by the high prices was alleviated or not, the ultimate outcome remains a tragedy. In another post, a member mentioned volume measurement methods. To be honest, this is a solution, but it seems there are no ready-made commercial products available. What should we do? It still hasn’t been solved. Perhaps there are other ways; we welcome everyone to share their thoughts.
Create a control device for volumetric, fixed-volume discharge – if one knows the volume and the discharge cycle time, can the flow rate be determined? Just trying to stimulate discussion – where are everyone’s replies? :)