چكيده به لاتين
One of the most important processes in gas refineries is the process of dehydration of natural gas by using multi-layer adsorption towers. This unit removes water from natural gas by using fixed bed adsorbents and prepares it to send to the downstream cryogenic separation unit. Due to the impossibility of any changes in an under operation industrial unit, this study examines the effect of each adsorbent layer along with the effect of operational variables using the mathematical model. The present study is important because the developed model validated considering real data from industrial unit.
By examining the results of the modeling, it is concluded that if using an active alumina layer alone, tower efficiency and break through time will be decreased down to 0.5 hours, in case of using a molecular sieve with a size of 5-3 mm, is 25.24 hours, and if the bed fill with the molecular sieve layer with a size of 2-3 mm, breakthrough time increases up to 30 hours. Also, by increasing in temperature, gas flow rate and inlet impurity, breakthrough will be happen early and by increasing in the pressure of the inlet gas tower will be operated efficiently. Due to the changing equilibrium and kinetic conditions in each of the adsorbents, the length of the mass transfer region will change in each of the layers, which will be considered in the design of multi-layer adsorption towers. The change over the mass transfer region has a direct impact on the breakthrough curve and length of the unused bed.
Keywords: Adsorption Process, Molecular Sieves, Design and mathematical Modeling, Gas processing
