Key Takeaways & Executive Findings
- •• • Net liquid cross-zone flow proportion ranges from -0.325 to -0.370, with net flow from swirl to packing zone, indicating that under all tested conditions, liquid preferentially moves toward the packing zone, which is critical for designing liquid distribution in absorption processes. • • Net gas cross-zone flow proportion ranges from 0.022 to 0.310, with net flow from packing to swirl zone, showing that gas preferentially moves to the swirl zone, which enhances gas-liquid contact in that region, beneficial for dust removal applications. • • Gas loss flow proportion varies from -0.047 to -0.319, and peaks at a liquid spray density of 92.26 m3/(m2·h), indicating that gas cross-zone flow resistance is maximized at intermediate liquid loads, which must be considered for optimizing operating windows. • • At low gas kinetic energy factors (0.41-0.82 m/s·(kg/m3)0.5) and low liquid spray densities (52.72-72.49 m3/(m2·h)), the packing zone handles at least 83.7% of liquid and 36.3% of gas, maximizing its liquid holdup advantage for absorption; at high gas kinetic energy factors (1.64-2.05 m/s·(kg/m3)0.5) and high liquid spray densities (112.03-131.80 m3/(m2·h)), the swirl zone handles at least 18.7% of liquid and 81.2% of gas, enhancing dust removal efficiency.
Abstract
The composite tridimensional rotational flow sieve tray (CTRST) integrates a packing zone and a swirl zone to enhance gas-liquid contact, yet its application range and structural optimization are hindered by unclear cross-zone flow distribution mechanisms. This study experimentally investigates gas-liquid cross-zone distribution and flow loss in both zones, introducing net cross-zone flow proportions for gas and liquid phases to quantify inter-zone flow. Under tested conditions, the net liquid cross-zone flow proportion ranged from -0.325 to -0.370, indicating net liquid flow from the swirl zone to the packing zone, while the net gas flow proportion ranged from 0.022 to 0.310, indicating net gas flow from the packing zone to the swirl zone. Analysis of loss flow ratios revealed that liquid spray density and gas kinetic energy factor had minor influence on net liquid loss flow proportion (always less than -0.037), suggesting low resistance to liquid exchange. Conversely, gas loss flow proportion varied significantly from -0.047 to -0.319, indicating substantial resistance to gas cross-zone interaction. This gas loss ratio initially increased then decreased with liquid spray density, peaking at 92.26 m3/(m2·h), and increased with gas kinetic energy factor. A predictive model for net cross-zone flow proportions was developed, correlating operational parameters with flow loss intensity, providing theoretical support for optimizing tray design and operation.
1. Introduction
Conventional sieve trays suffer from limited mass transfer efficiency and narrow operating ranges due to poor gas-liquid distribution across different zones. The composite tridimensional rotational flow sieve tray (CTRST) integrates a packing zone and a swirl zone to enhance gas-liquid contact, but its design optimization is hampered by an incomplete understanding of cross-zone flow dynamics. Specifically, the mechanisms governing gas and liquid exchange between the packing and swirl zones remain unclear, leading to unpredictable performance under varying operational conditions.
This study addresses this bottleneck by experimentally quantifying net cross-zone flow proportions and loss flow ratios for both phases. By systematically varying liquid spray density and gas kinetic energy factor, we delineate how these parameters influence inter-zone flow direction and magnitude. The introduction of net cross-zone flow proportions provides a quantitative basis for optimizing tray geometry and operating guidelines, enabling tailored performance for absorption or dust removal applications.
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Ping HUO, Yue MA, Hongkai WANG, Meng TANG (2026). Study on Net Cross-Zone Flow Characteristics of Composite Tridimensional Rotational Flow Sieve Tray. The Chinese Journal of Process Engineering. https://doi.org/10.12034/j.issn.1009-606X.225222
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Frequently Asked Questions
What is the physical significance of the net cross-zone flow proportion being negative for liquid and positive for gas?
The negative liquid proportion (-0.325 to -0.370) indicates that the net liquid flow is from the swirl zone to the packing zone, meaning more liquid enters the packing zone than leaves it. Conversely, the positive gas proportion (0.022 to 0.310) indicates net gas flow from the packing zone to the swirl zone. This counter-current cross-zone flow enhances gas-liquid contact in both zones, but the magnitudes suggest that the packing zone acts as a liquid reservoir while the swirl zone promotes gas dispersion.
How does the gas loss flow proportion vary with liquid spray density and gas kinetic energy factor, and what are the implications for tray operation?
The gas loss flow proportion ranges from -0.047 to -0.319. It initially increases (becomes more negative) with liquid spray density, peaking at 92.26 m3/(m2·h), then decreases. This suggests that at moderate liquid loads, gas cross-zone flow is most hindered, possibly due to increased liquid holdup in the packing zone. With increasing gas kinetic energy factor, the gas loss proportion increases, indicating that higher gas velocities overcome some resistance but also lead to higher pressure drops. Operators should avoid the peak loss region to minimize energy losses.
What are the optimal operating conditions for absorption versus dust removal applications?
For absorption, low gas kinetic energy factors (0.41-0.82 m/s·(kg/m3)0.5) and low liquid spray densities (52.72-72.49 m3/(m2·h)) are recommended, as the packing zone handles at least 83.7% of liquid and 36.3% of gas, maximizing liquid holdup and gas-liquid contact time. For dust removal, high gas kinetic energy factors (1.64-2.05 m/s·(kg/m3)0.5) and high liquid spray densities (112.03-131.80 m3/(m2·h)) are preferred, as the swirl zone handles at least 81.2% of gas, promoting intense gas-liquid mixing and particle capture.
How does the predictive model for net cross-zone flow proportions aid in tray design?
The model correlates net cross-zone flow proportions with operational parameters (liquid spray density and gas kinetic energy factor), allowing engineers to predict flow distribution without extensive experimentation. This enables optimization of tray geometry (e.g., hole size, packing height) to achieve desired flow patterns for specific applications, reducing trial-and-error in design.
What are the limitations of this study and what future work is suggested?
The study is limited to a specific range of operating conditions and does not include mass transfer efficiency measurements. Future work should extend the range of liquid and gas flow rates, incorporate pressure drop and mass transfer data, and investigate scale-up effects. Additionally, computational fluid dynamics (CFD) simulations could provide deeper insights into local flow phenomena.
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