In order to predict the pressure drop, collection efficiency, velocity, temperature and mole fraction of vapor in an industrial venturi scrubber with water spraying for converter gas cooling, a three-dimensional model...In order to predict the pressure drop, collection efficiency, velocity, temperature and mole fraction of vapor in an industrial venturi scrubber with water spraying for converter gas cooling, a three-dimensional model of heat and mass transfer with phase change is established. The gas flow and liquid droplets are treated as a continuous phase with a Eulerian approach and as a discrete phase with a Lagrangian approach, respectively. The coupled problem of heat, force, and mass transfers between gas flow and liquid droplets is solved by a commercial computational fluid dynamics（CFD） package, FLUENT. The numerical results show that the water injections have an important influence on the distributions of pressure, velocity, temperature, and mole fraction of vapor, especially for the spraying region in the throat. In the spraying region, the pressure drop is higher and the velocity is lower than in other regions due to the gas-droplet drag, while the temperature is lower because the droplet absorbs large amounts of heat from the high temperature gas and the mole fraction of vapor is higher due to the phase change of the liquid droplet. A number of cases with different Water-to-gas volume flow ratios and baffle openings were simulated. The dependence of pressure drop, velocity, temperature, mole fraction of vapor, and collection efficiency on both the water-to-gas volume flow ratio and baffle opening are analyzed. The good agreements between simulation results and experiment data of pressure drop, temperature, and collection efficiency validate the model. The model should facilitate optimization of the venturi scrubber design in order to give better performance with lower pressure drops and higher collection efficiency.展开更多
Venturi scrubbers are usually used for large particles cleaning in turbulent gaseous flow. In this work, submicron particles scrubbing in laminar forced convection dusty air flow in a rectangular venturi scrubber have...Venturi scrubbers are usually used for large particles cleaning in turbulent gaseous flow. In this work, submicron particles scrubbing in laminar forced convection dusty air flow in a rectangular venturi scrubber have been numerically simulated. Hydrodynamics effects and scrubbing process are investigated in detail. Results are presented as flow velocity, axial pressure, streamlines pattern, particles and droplets mass fraction profile, and collect efficiency. They show that venturi scrubbers can be efficient for submicron particles scrubbing. In fact, a better collect efficiency is obtained at high particles-droplets residence time, high ratio droplets concentration/particles concentration, low venturi diameter ratioand low Reynolds numbers. There is a critical Reynolds number value for which the collect efficiency becomes very low and tends to be constant.展开更多
This study uses computational fluid dynamics to survey the gas‒liquid flow hydrodynamics of a self-priming venturi scrubber with and without ring baffles.Based on the simulation results,we explore how the structure an...This study uses computational fluid dynamics to survey the gas‒liquid flow hydrodynamics of a self-priming venturi scrubber with and without ring baffles.Based on the simulation results,we explore how the structure and configuration parameters such as baffle height,opening-area ratio,and baffle thickness affect the injection flow rate and the homogeneity of the gas‒liquid mixture.In addition,we report the best structure and configuration parameters for the ring baffle.The best position for the ring baffle is at nearly 7/16 of the length of the diffuser above the throat.Having the baffle too near the throat causes large pressure loss,decreasing the injection flow rate.The decrease in opening-area ratio leads to a lower injection flow rate and a more homogeneous gas‒liquid mixture.The optimal value depends on the requirement of the injection flow rate.For the baffle thickness,5 mm is recommended;an overly thick baffle decreases the homogeneity of the gas‒liquid mixture near the throat.All structure parameters and configuration parameters must satisfy the requirement imposed by the injection flow rate and scrubbing efficiency.展开更多
Based on the experimental data by a full scale test model and the relevant existing achievements, four new concepts of group dust scrubbers were designed in the paper. The new dust scrubbers consist of two to four com...Based on the experimental data by a full scale test model and the relevant existing achievements, four new concepts of group dust scrubbers were designed in the paper. The new dust scrubbers consist of two to four common dust separators in series: wet fan, wet Venturi and foam filter bed. Wetting and foaming agents are used to increase the efficiency of dust separation. High efficiency is not required for each part of the group dust scrubbers, but the whole system has a high working reliability. All parts of the group dust scrubbers have the most suitable separating efficiency for different size and concentration of dust particles in airflow, according to their technical features. Four group dust scrubbers have a high efficiency from 94.4% to 99.7% for separating respirable dust at a rational cost.展开更多
The Venturi-rod deck tray is a type of dual flow trays used in flue gas desulfurization(FGD) process. In this paper, the hydrodynamic characteristics of the Venturi-rod deck tray were studied in the experiments and co...The Venturi-rod deck tray is a type of dual flow trays used in flue gas desulfurization(FGD) process. In this paper, the hydrodynamic characteristics of the Venturi-rod deck tray were studied in the experiments and compared with the conventional sieve tray. Results showed the turndown ratio of this tray was in the range of 2.71—3.77, which was by 9% higher than the sieve tray. Besides, the pressure drop of this tray was by more than 50% lower than the sieve tray. Based on the experimental data, the correlation functions for the pressure drop and the froth height, respectively, were obtained. The industrial scale up practice of this tray in FGD process was described with the efficiency of this tray demonstrated.展开更多
基金supported by Beijing Novel Program, China (Grant No. 2008B16)
文摘In order to predict the pressure drop, collection efficiency, velocity, temperature and mole fraction of vapor in an industrial venturi scrubber with water spraying for converter gas cooling, a three-dimensional model of heat and mass transfer with phase change is established. The gas flow and liquid droplets are treated as a continuous phase with a Eulerian approach and as a discrete phase with a Lagrangian approach, respectively. The coupled problem of heat, force, and mass transfers between gas flow and liquid droplets is solved by a commercial computational fluid dynamics（CFD） package, FLUENT. The numerical results show that the water injections have an important influence on the distributions of pressure, velocity, temperature, and mole fraction of vapor, especially for the spraying region in the throat. In the spraying region, the pressure drop is higher and the velocity is lower than in other regions due to the gas-droplet drag, while the temperature is lower because the droplet absorbs large amounts of heat from the high temperature gas and the mole fraction of vapor is higher due to the phase change of the liquid droplet. A number of cases with different Water-to-gas volume flow ratios and baffle openings were simulated. The dependence of pressure drop, velocity, temperature, mole fraction of vapor, and collection efficiency on both the water-to-gas volume flow ratio and baffle opening are analyzed. The good agreements between simulation results and experiment data of pressure drop, temperature, and collection efficiency validate the model. The model should facilitate optimization of the venturi scrubber design in order to give better performance with lower pressure drops and higher collection efficiency.
文摘Venturi scrubbers are usually used for large particles cleaning in turbulent gaseous flow. In this work, submicron particles scrubbing in laminar forced convection dusty air flow in a rectangular venturi scrubber have been numerically simulated. Hydrodynamics effects and scrubbing process are investigated in detail. Results are presented as flow velocity, axial pressure, streamlines pattern, particles and droplets mass fraction profile, and collect efficiency. They show that venturi scrubbers can be efficient for submicron particles scrubbing. In fact, a better collect efficiency is obtained at high particles-droplets residence time, high ratio droplets concentration/particles concentration, low venturi diameter ratioand low Reynolds numbers. There is a critical Reynolds number value for which the collect efficiency becomes very low and tends to be constant.
文摘This study uses computational fluid dynamics to survey the gas‒liquid flow hydrodynamics of a self-priming venturi scrubber with and without ring baffles.Based on the simulation results,we explore how the structure and configuration parameters such as baffle height,opening-area ratio,and baffle thickness affect the injection flow rate and the homogeneity of the gas‒liquid mixture.In addition,we report the best structure and configuration parameters for the ring baffle.The best position for the ring baffle is at nearly 7/16 of the length of the diffuser above the throat.Having the baffle too near the throat causes large pressure loss,decreasing the injection flow rate.The decrease in opening-area ratio leads to a lower injection flow rate and a more homogeneous gas‒liquid mixture.The optimal value depends on the requirement of the injection flow rate.For the baffle thickness,5 mm is recommended;an overly thick baffle decreases the homogeneity of the gas‒liquid mixture near the throat.All structure parameters and configuration parameters must satisfy the requirement imposed by the injection flow rate and scrubbing efficiency.
基金FoundationofChinaScholarshipCouncilforAbroad! (No .975 14 0 0 8)
文摘Based on the experimental data by a full scale test model and the relevant existing achievements, four new concepts of group dust scrubbers were designed in the paper. The new dust scrubbers consist of two to four common dust separators in series: wet fan, wet Venturi and foam filter bed. Wetting and foaming agents are used to increase the efficiency of dust separation. High efficiency is not required for each part of the group dust scrubbers, but the whole system has a high working reliability. All parts of the group dust scrubbers have the most suitable separating efficiency for different size and concentration of dust particles in airflow, according to their technical features. Four group dust scrubbers have a high efficiency from 94.4% to 99.7% for separating respirable dust at a rational cost.
基金The financial support from the Science Fundation of China University of Petroleum,Beijing(No.2462106 YJRC026)the SINOPEC project fund(No.109119)
文摘The Venturi-rod deck tray is a type of dual flow trays used in flue gas desulfurization(FGD) process. In this paper, the hydrodynamic characteristics of the Venturi-rod deck tray were studied in the experiments and compared with the conventional sieve tray. Results showed the turndown ratio of this tray was in the range of 2.71—3.77, which was by 9% higher than the sieve tray. Besides, the pressure drop of this tray was by more than 50% lower than the sieve tray. Based on the experimental data, the correlation functions for the pressure drop and the froth height, respectively, were obtained. The industrial scale up practice of this tray in FGD process was described with the efficiency of this tray demonstrated.
