Research On Simulation And Safety Design Of Vertical Radial Flow Adsorber

Radial flow adsorber is more suitable for large-scale development trend of air separation plants due to its small footprint,low bed pressure drop and many other advantages.However,non-uniform flow distribution usually exists in a radial flow adsorber because of its structural characteristics,which seriously restricts the efficiency of adsorption and desorption,and even results in an accident of air separation system.Therefore,studying the influencing factors of uniform air flow in adsorber and optimizing the structural parameters of adsorber will improve its performance and ensure the safe operation of air separation plant.The main works of this paper include:?1?Considering the effect of mass transfer and heat transfer on the uniformity of airflow,the two-dimensional unsteady mathematical model was established to simulate the H₂O and CO₂competitive adsorption process in the activated alumina and molecular sieve adsorbent.A Linear Driving Force?LDF?equation was used to describe the mass transfer process,and the multi-component realistic interactive Langmuir-BET?R-LBET?equation was used to describe the adsorption equilibrium of two-component gas in the activated alumina and molecular sieve adsorbent.Results showed that above models can describe the heat and mass transfer process of air in adsorption bed well.?2?A relatively complete axisymmetric model was constructed,which fully considered the influence of the structure of deflector,spherical dish head,and the imperforated plates in the vertical radial flow adsorber.The problem of"dead zone"at the top of the desorption process was effectively solved by installing a kind of breathing valve,that is,flow velocity of"dead zone"at the top of adsorber is small,thus it is difficult to desorb them sufficiently due to the presence of the imperforated region.It prevents the hazard of explosion caused by accumulation of acetylene gas in liquid oxygen.?3?Structural parameters of the airflow uniformity in the adsorber were analyzed,including the ratio of cross-sectional area of central pipe to that of annular channel,the porosity of adsorbent,the thickness of adsorption bed and the shape of the airflow distributor in central channel.Taking into account of many factors on adsorption and desorption process,this paper puted forward a more integrated optimization scheme.