Study on the structural optimization of a gas distributor of vertical adsorption tower based on CFD

The vertical adsorption tower serves as a crucial tool for the adsorption and separation of methane in the coalbed. Nonetheless, the complexities and variations inherent in the adsorption process pose challenges that hinder the fulfillment of actual production requirements. To enhance the uniformity of gas distribution, the installation of an appropriate gas distributor becomes necessary. To investigate this matter, computational fluid dynamics (CFD) was employed to conduct numerical simulations comparing the effects of various gas distributors, including no gas distributor, conical gas distributor, truncated cone gas distributor, and a combination of sieve plate and baffle on the flow field of coalbed methane within the vertical adsorption tower. The simulation results were evaluated based on the smoothness of the velocity vector and velocity curve, enabling the determination of the uniformity of the gas distribution. With the installation of a single sieve plate as the gas distributor, the majority of airflow predominantly exits from the middle section of the vertical adsorption tower; however, the distribution is still insufficiently uniform. The incorporation of Type I and Type II gas distributors improved the gas flow field to some extent, but uneven distribution persisted. Notably, the installation of a type III gas distributor consisting of a combination of sieve plate and baffle enhances the uniformity of gas distribution. Further optimization of the type III gas distributor revealed that the most favorable outcome, with the greatest uniformity and effectiveness, occurs when the baffle diameter (d) measures 0.1 m and the distance (h) between the sieve plate and the baffle measures 0.15 m, resulting in a ratio of (d) to (h) equal to k = 1.5.