Companies that use cryogenic gas may not know it, but they are heavily reliant on the functioning of their vaporizers.
Vaporizers are the piece of the equipment that actually transform the liquid gases into its gaseous form If the vaporizers are compromised, businesses run the risk of pulling liquid gas into their line.
Cryogenic tanks are designed to hold the liquid gas, but the lines are designed for gaseous products. Cryogenic liquid in the line may cause catastrophic damage. This is why having well-working vaporizers should be one of the priorities of any cryogenic tank owner, and one of the most common vaporizer issues is ice build-up.
Why are your vaporizers icing up? Here are three reasons why:
1. You are pulling too much gas too quickly
The appearance of frost on vaporizers is a natural occurrence during the cryogenic re-gasifying process. Liquid cryogens must remain in a freezing state to remain liquid, but when the liquid is pulled into the vaporizers they are changed into a gas. As the vaporizers heat the liquid gas, frost accumulates on the outside of the vaporizer. This occurrence is inherent in the design of the vaporizers, but consequently, as frost and ice build-up the surface area for heat transfer minimizes. Most operators can limit build-up by having multiple vaporizers or alternating between units to allow them to defrost.
This process works on paper, but what happens when production or service duties call for more gas than what is capable of for the current vaporizers? Severe ice build-up.
The picture shows how pulling too much gas beyond the design of the vaporizers can lead to severe ice build-up. This ice build-up limits the amount of surface area available to re-gasify the liquid cryogens to a gas. Ice must be removed as a short-term solution, but if production or service requires this high of gas consumption, new installations or other methods must be considered.
2. There is not enough heat in the atmosphere for defrosting
There is a limited time in which vaporizers can be effective. The de-icing of an atmospheric vaporizer can be done naturally if the temperature of the air is hot enough (above 0 C). However, if the ambient temperature remains cold for a long period (for example a few weeks or even a few months), the ice is not able to defrost. Consequently, as more liquid is pulled, more and more ice build-up will occur.
3. Not enough space in between vaporizers
As companies grow, the numbers of units increase and spacing between units reduces. More vaporizers can be beneficial for allowing more adequate time for defrosting, but if there is not enough space for adequate airflow, space where the vaporizers are located is only going to get colder.
Think about it as an icebox. If you place one ice cube in the icebox, it’s going to melt faster than if you put a handful of ice in the icebox. There needs to be a sufficient amount of space in-between vaporizers to increase airflow and to limit the icebox situation from happening.
The best way to prevent ice build-up is to keep a close eye on the vaporizers to see if there are any changes due to the above reasons.
In summary, vaporizers can ice up for a variety of reasons: pulling too much product, lower temperatures, or vaporizers are too close to one another. Vaporizers are designed to work in a variety of different climates and situations. Vaporizers do not suddenly ice up overnight so a careful eye should be all you need and when ice builds up, call an experienced contractor to take the ice off for you.