Simulation And Experiment Research Of Gas Desulfurization And Decarburization In Cyclone Reactor

Absorption of H₂S and CO₂ by alkanol amine solution is one of the most popular technology in natural gas purification industry.Foaming in amine desulfurizing solution is often observed in the natural gas treating plant which resulting in fog carrying and excessive amine solution losing.Based on these problem,this paper proposes to use cyclone reactor with strong turbulence to enhance mass transfer of desulfurization and decarburization,which which can reduce solvent loss and promote separation efficiency.Specifically,this paper has observed the change of n value and pressure drop under different operating conditions and structure parameters using cyclone reactors with the nominal diameters of 25 mm,35 mm,50 mm and 75 mm.The numerical simulation is used to investigate the shear strength distribution under different nominal diameter.Experiments are used to study the removal efficiency and selectivity desulfurizing under different working conditions.Component transport model is adopted to discuss concentration distribution in cyclone reactor.The main conclusions are as follows:?1?The value of tangential velocity indicator n of the quasi-free vortex zone inside the cyclone is independent of the radial position and changes slightly with the axial position.The n value is related to the structural parameter of the cyclone separator.With the increasing diameter of cyclone,the increasing diameter of exit pipe,and decreasing immersion depth of the exit pipe,the n value increases accordingly.This is also compliant with the internal pressure drop of the cyclone reactor.The effect of tangential shear to the droplet in three-dimensional distribution is bigger than that of the radial shear and axial shear.Shear failure is mainly distributed in the center and side wall of cyclone reactor,approximately accounting for 22%.The size of the shear strength in strong shear zone is DN25>DN35>DN50>DN75.Tangential shear distribution has no apparent influence with the increase of import flow,but the increase of inlet flow will increase the peak of the strong shear zone.?2?Pressure drop is proportional to the second power of import flow under the same inlet concentration.36-39 m3/h is the best inlet velocity ensuring the process of adsorption and guaranteeing gas-liquid separation.CO₂ removal efficiency increases first and after that it has an approximate constant with the increase of MDEA concentration.The efficiency is independent of CO₂ concentration.When H₂S is occurring in the mixed gases,the absorption of H₂S by MDEA surges up while the removal efficiency of CO₂ declines.?3?The tangential velocity distribution also conforms to the law of quasi-free vortex in cyclone reactor.In the interface of quasi-forced vortex zone,the tangential velocity increases sharply to a maximum.The radial velocity mainly has a vector direction from the wall to the axis.The direction of the axial velocity points to the bottom,the zone of the exit pipe,the axial velocity is upward.CO₂ concentration and MDEA solution concentration quickly reduce after the distance of half a circle.The variation tendency of concentration is quite similar to spinning vortexes.With the increase of inlet CO₂ concentration,the speed of CO₂ absorption with MDEA solution has diminished.The best mole ratio is 0.25 makes CO₂ removal efficiency highest.With low energy consumption,the absorption process of cyclone has obvious economic and environmental advantages compared to other metholds,the conclusion provides the experimental and theoretical foundation for an engineering application of natural gas desulfurization and decarburization.