Rotary gas-gas heat exchangers (GGHs) are pivotal for waste heat recovery in low- and medium-temperature denitrification systems of cement kilns. This study examines the performance of GGHs within such systems by coupling computational fluid dynamics (CFD) with the response surface method (RSM), introducing overall system performance (OSP) as the principal optimization criterion. The investigation systematically elucidates the effects of treated flue gas inlet temperature, inlet velocity, and rotor speed on GGH efficiency. Findings reveal that OSP increases with rotor speed but reaches a plateau beyond 1 rpm; it decreases with higher inlet velocity and increases with higher inlet temperature. Response surface analysis identifies treated flue gas inlet temperature as the most influential parameter, highlighting a synergistic effect between rotor speed and inlet temperature, alongside an antagonistic interaction between inlet temperature and inlet velocity. To ensure safe system operation, engineering constraints were incorporated into the optimization framework using a Box-Behnken design. The optimal operational parameters were determined as a treated flue gas inlet temperature of 250°C, inlet velocity of 8 m/s, and rotor speed of 1 rpm, yielding a maximum OSP of 107.74. The integrated CFD-RSM methodology and constraint-aware optimization strategy presented in this study offer a practical reference for enhancing the operational efficiency of industrial waste heat recovery systems, particularly in cement kiln SCR applications.

Nitrogen oxides (NO_x) and particulate matter (PM) present significant risks to both human health and environmental sustainability. The Integrated Dust Removal and Denitrification Technology (DRDt) offers a more efficient and cost-effective solution for achieving ultralow industrial flue gas emissions; however, its effectiveness is undermined by low catalyst load rates and poor stability in filter materials. This study addresses these limitations by modifying conventional PTFE filter media (PTFE-Tim) through the incorporation of sodium alginate (SA) and dopamine (DA) as modifiers, resulting in two new filter materials: PTFE–SA–MOF and PTFE–DA–MOF. By optimizing the parameters of an orthogonal experimental design, we identified the ideal preparation conditions for these composite materials. The addition of SA and DA enhanced the bonding between the catalyst (Mn–Cu–MOF) crystal particles and the PTFE fibers through mechanisms such as ion exchange, hydrogen bonding, and adhesion. Consequently, the catalyst loading rate and stability of the DRDt filters were significantly improved. Specifically, the PTFE–SA–MOF and PTFE–DA–MOF filters achieved high catalyst loading rates of 15.97% and 15.86%, these values represent improvements of 2.53 and 2.51 times, while maintaining excellent stability, with mass retention rates of 98.64% and 98.27%, respectively, over the conventional PTFE-Tim filter.

In the building environment, PM2.5 seriously affects people’s health and quality of life, so it is necessary to study the particle deposition characteristics. In addition, it is essential for a thorough investigation of the dust removal mechanism to understand the non-spherical particles deposition characteristics. The stacking angle experiment was used to calibrate the discrete element simulation parameters. And four simulation methods (CFD-DPM, CFD-DEM, API interface loading drag model based on EDEM software and EDEM simulation) were used to numerically simulate the non-spherical particles deposition characteristics. The optimal simulation method EDEM was applied to study the non-spherical particles deposition characteristics in filter media, which saves the calculation time obviously. On this basis, the particle parameters on the particle deposition characteristics of filter media were investigated. The results show that the deposition rate of non-spherical (special shape) particles with the same volume is basically consistent on the filter media, hence it is more realistic that the dust actual shape is simplified into the triangular-shaped particles. As the particle size increases, the number of deposited particles on the filter media decreases. And the larger the particle size, the more dispersed the distribution. It has a significant impact on the number of particles deposited on the filter media when the particle velocity is 0.1 m/s. The particle deposits to the lower part of the filter media in the form of a parabola and deviates from the outlet seriously at 0.1 m/s. Moreover, it has little effect on the number of particle deposition at the other velocities, and most particles are deposited on the upper part of the filter media with the increase of particle velocity.