Is so-called super regeneration of molecular sieves still necessary nowadays?
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It can be seen that project designs mostly use steam heaters with 1.3 MPa steam, whose saturation temperature is 175°C; this does not reach the super-regeneration temperature required by molecular sieves. Are molecular sieves no longer requiring super-regeneration these days? What to do in the long run? What to do if water gets in?
As long as the temperature meets the requirements, I think it’s okay to proceed. Steam heaters generally leak just as easily as well.
What is the super-regeneration method for molecular sieves? Could you give me a rough idea?
If high-temperature activation is required, 1.3 MPa steam is definitely not sufficient; either a stream of 2.5 MPa steam must be used, or an electric heater must be employed. Today’s steam heaters are getting larger and larger, and as far as I know, their leakage rate is quite high!
Simply put, once the adsorption capacity of the molecular sieve reaches a certain level, the regeneration gas temperature of around 170 degrees, which is normal under usual conditions, is not sufficient to fully regenerate the molecular sieve. In such cases, a higher temperature such as 250 degrees is required to carry out a more thorough regeneration of the molecular sieve; this is what is commonly referred to as super regeneration, or high-temperature activation.
It is true that initial activation requires high temperatures; typical designs use steam heaters in combination with electric heaters to achieve the necessary temperature. During normal operation, no extremely high temperatures are needed, unless the molecular sieve is degraded. The downside is that such high temperatures increase energy consumption, and they also reduce the lifespan of the molecular sieve
Oh, I see. It’s just that we use a different term for it; we call it special regeneration. I thought that super regeneration required even higher temperatures than special regeneration
That is, the regeneration temperature reaches 250 degrees Celsius until equilibrium is achieved at the inlet and outlet of the molecular sieve~~
It can be done by using the current heater for regeneration, until the temperatures at the inlet and outlet become equal~~
They’re all the same; there’s also something called high-temperature activation – in any case, it’s just a slightly higher temperature than that used for normal regeneration!
Then why aren’t most air separation units equipped with electric heaters? I consulted some experienced professionals, including manufacturers of molecular sieves, and they all said it’s not necessary, as the manufacturing processes are different now from before. As a front-line employee, I want to get one; what kind of data can convince my supervisor to approve it?