In the dehydration section of natural gas production, why can the outlet temperature drop below 0 degrees when hot blowing of the dehydration tower begins?
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In the dehydration section of natural gas production, why does the outlet temperature drop below 0 degrees when hot blowing starts in the dehydration tower, causing frost to form on the pipes on site? ? ? ? ?
When molecular sieves absorb moisture, heat is released; generally, at the initial stage of adsorption, the temperature of the gas increases. The extent of this temperature rise depends on the type of molecular sieve. I have seen temperature rises of up to 40 degrees. During thermal desorption, heat is absorbed, so it is indeed an endothermic process. Frost formation is also normal, but it lasts for a short time. Once the peak period of desorption passes, the high-temperature regeneration gas quickly raises the temperature again. It’s sufficient to insulate the inlet and outlet pipes. Additionally, if methanation proceeds well, use less 13X and more 4A
A similar situation has been observed during the dehydration and regeneration of natural gas molecular sieves. The main reason is the vaporization of some of the adsorbed heavy hydrocarbons.