Structural Optimization of Reactor for the Enhancement of CO₂ Electrochemical Reduction Based on Gas–Liquid Mixing Flow Model

Abstract

The CO2 electrochemical reduction reaction (CO2ERR) is heralded for carbon dioxide and renewable energy utilization. However, complexities in catalyst optimization and reactor structure research hinder its practical application. Herein, rather than traditional catalyst optimization, emphasis is placed on refining the reactor structure to enhance gas–liquid mixing. The goal is to raise the CO2 concentration in the reaction zone and extend its residence refining CO2ERR. Building on prior reactor designs, this work introduces the N‐reactor (the nozzle‐type reactor) with a ring electrode suited for gas–liquid mixing and reaction interplay. Through finite element simulations using the gas–liquid flow model, compared with the S‐reactors (the wide‐straight‐type reactor and the narrow‐straight‐type reactor), the N‐reactor's ring electrode shows a 12.99% CO2 concentration rise in the electrode zone and a 67.11% surge at the cathode exit. As a consequence, the total concentration of the product methanol is increased by 6.37%, with a maximum concentration increase of 26.96% and a concentration increase of 49.08% at the cathode outlet. These results validate the feasibility of optimizing the reaction from the perspective of gas–liquid mixing flow and provide novel methods and ideas for further optimization of CO2ERR, contributing to the practical application of the technology.

Investigation of Non-Uniform Inflow Effects on Impeller Forces in Axial-Flow Pumps Operating as Turbines

“…Additionally, considering the existence of an inlet elbow, transmission shaft, and other structural components, the inflow conditions during the reverse operation of axial-flow pumps are poor, resulting in reduced uniformity in fluid distribution within the impeller's front section. The formation of non-uniform inflow induces an imbalance in impeller forces, increasing the complexity of internal flow inside the PAT [10][11][12]. This leads to poor stability of the axial PAT with lower efficiency, vibrations, and a limited high-efficiency range [13,14], presenting a substantial menace to the secure and stable operation of hydraulic machinery.…”

“…It was revealed that non-uniform inflow resulted in increased impeller axial force fluctuations, pressure pulsation levels, and hydraulic losses, potentially contributing to a subsequent reduction in pump head and efficiency [20][21][22]. Meng et al [10] analyzed the impact of non-uniform inflow within a vertical axial-flow pump and found that the increasing inflow non-uniformity would increase the stress of the impeller, consequently raising the risk of failure due to fatigue. In a study conducted by Wang et al [23,24], research results showed that the reduced uniformity of inflow resulted in a decrease in pump head and operational efficiency, which made the flow inside the impeller more complex and impeller forces more unbalanced.…”