For the high-temperature and short-contact time gas-solid reaction process,riser and downer are considered appropriate reactors.To realize an intensive and complete mixing of reactants with catalysts,the feed raw is a...For the high-temperature and short-contact time gas-solid reaction process,riser and downer are considered appropriate reactors.To realize an intensive and complete mixing of reactants with catalysts,the feed raw is always introduced in the form of high-speed jets.In this study,in order to investigate the mixing effects of different types of high-speed jets in riser and downer,traceable ozone is injected with the high-speed feed jets to react with catalyst particles.By detecting the decomposition of ozone,the gas-solid mixing and reaction in riser and downer under the influence of both co-current and counter-current injections are analyzed.The relative ozone concentration is used to reflect the location reaction extent and its radial nonuniformity index is proposed to compare the results in riser and downer.It is found that the jet influence zone in downer provides a relatively better environment for the mixing of feed jets with catalysts.In the riser,introduction of counter-current injections could improve the uniformity of gas-solid mixing in the initial contact region of feed with catalysts.展开更多
Gas solid two-phase turbulent plane jet is applied to many natural s it uations and in engineering systems. To predict the particle dispersion in the ga s jet is of great importance in industrial applications and in ...Gas solid two-phase turbulent plane jet is applied to many natural s it uations and in engineering systems. To predict the particle dispersion in the ga s jet is of great importance in industrial applications and in the designing of engineering systems. A large eddy simulation of the two-phase plane jet was con d ucted to investigate the particle dispersion patterns. The particles with Stokes numbers equal to 0 0028, 0 3, 2 5, 28 (corresponding to particle diameter 1 μm , 10 μm, 30 μm, 100 μm, respectively) in \%Re\%=11 300 gas flow were studied. The simulation results of gas phase motion agreed well with previous experimental re sults. And the simulation results of the solid particles motion showed that part icles with different Stokes number have different spatial dispersion; and that p articles with intermediate Stokes number have the largest dispersion ratio.展开更多
基金the National Key Research and Development Program of China(grant No.2022YFA1506200)the open foundation of State Key Laboratory of Chemical Engineering(grant No.SKL-ChE-23B02).
文摘For the high-temperature and short-contact time gas-solid reaction process,riser and downer are considered appropriate reactors.To realize an intensive and complete mixing of reactants with catalysts,the feed raw is always introduced in the form of high-speed jets.In this study,in order to investigate the mixing effects of different types of high-speed jets in riser and downer,traceable ozone is injected with the high-speed feed jets to react with catalyst particles.By detecting the decomposition of ozone,the gas-solid mixing and reaction in riser and downer under the influence of both co-current and counter-current injections are analyzed.The relative ozone concentration is used to reflect the location reaction extent and its radial nonuniformity index is proposed to compare the results in riser and downer.It is found that the jet influence zone in downer provides a relatively better environment for the mixing of feed jets with catalysts.In the riser,introduction of counter-current injections could improve the uniformity of gas-solid mixing in the initial contact region of feed with catalysts.
文摘Gas solid two-phase turbulent plane jet is applied to many natural s it uations and in engineering systems. To predict the particle dispersion in the ga s jet is of great importance in industrial applications and in the designing of engineering systems. A large eddy simulation of the two-phase plane jet was con d ucted to investigate the particle dispersion patterns. The particles with Stokes numbers equal to 0 0028, 0 3, 2 5, 28 (corresponding to particle diameter 1 μm , 10 μm, 30 μm, 100 μm, respectively) in \%Re\%=11 300 gas flow were studied. The simulation results of gas phase motion agreed well with previous experimental re sults. And the simulation results of the solid particles motion showed that part icles with different Stokes number have different spatial dispersion; and that p articles with intermediate Stokes number have the largest dispersion ratio.
