Water has to be removed from natural gas to avoid hydrate formation and equipment corrosion. This is the case for natural gas either sent to pipelines or to liquefaction units (LNG). For LNG applications, water contents must be reduced typically down to 0.1 ppm vol.
The Multibed™ technology consists of an optimized combination of activated alumina on the top and molecular sieves on the bottom of the dryers. It can significantly reduce degradation and aging of the desiccant system while increasing desiccant life by 50% compared to molecular sieves only.
Molecular sieves are excellent adsorbents for soluble water. Upstream process upsets, resulting in rapid desiccant degradation reduce sieve capacity and increase pressure drop. Water which is not dissolved in hydrocarbons (free water) destroys some bonds between molecular sieves components (i.e. the binder and zeolite).