Time for sequential shutdown after carbon dioxide level exceeds the limit after passing through the molecular sieve
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Our carbon dioxide analysis after using the molecular sieve shows an overestimated value of 1 ppm, which becomes 3 ppm as a result of this overestimation; fifteen minutes later, the system shuts down automatically. I would like to ask everyone how this 15-minute time period is determined. Thank you
Actually, this value is considered empirical, and there’s no fixed standard for it. 3ppm*15min/1hr=0.75ppm means that, when at 0.75ppm for 1 hour, the total amount of CO2 absorbed by both is the same. Why would one want to jump out of the car, while the other doesn’t even call the police? It can be seen that this data applies only to a reaction time of 15 minutes when a large amount of CO2 enters the cold box, at levels greater than 3 ppm; there is no clear quantitative relationship with the actual concentration of CO2. Rather, it is likely related to the flow rate of the gas.
Some factories do not install this interlock system. After all, as long as attention is paid to the operation of the valves in the molecular sieve system, to the regeneration process, and to on-site inspections, there are generally no problems. Even if the adsorbent ages, the carbon dioxide level rises gradually, which helps to prevent such risks. As for the 15-minute time frame, it is likely intended to provide a buffer period, to allow for a reasonable decision to be made – whether it’s a false alarm or the molecular sieve has become over-adsorbed~~
Which manufacturer is your device from? Hangyang generally does not have such a 15-minute interlock shutdown time; it is rather the amount of dry ice that can be introduced within 15 minutes when the CO2 content in the air after passing through the molecular sieve is at 3 ppm. As for whether this amount can cause blockage in the heat exchanger, it depends on the amount permitted by the design – primarily on the extent to which such blockage affects the amount of air entering the tower, thereby leading to changes in the volume of product produced, or even causing complete blockage of the heat exchanger and forcing a shutdown ； There are also some process devices that can directly cause the expansion machine to stop operating ；
This should be Air Liquide, right~~~ I think those 3 ppm refer to the time it takes for the hydrocarbons in the air that exceed the specified levels to reach the main cooler; that’s my personal interpretation