Photocatalytic NOx abatement:mathematical modeling, CFD validation and reactor analysis

Abstract

\u3cp\u3eA 2D CFD model was implemented for the numerical simulation of NO \u3csub\u3ex\u3c/sub\u3e abatement in a photocatalytic reactor, considering the effect of relative humidity (10–60%), light intensity (0.3–13 W⋅m \u3csup\u3e−2\u3c/sup\u3e) and inlet NO concentration (0.1–1.0 ppm). Significant differences of NO \u3csub\u3ex\u3c/sub\u3e concentration at the catalytic surface and bulk gas were found (Δ \u3csub\u3emax\u3c/sub\u3e of ∼12% and ∼16% for NO and NO \u3csub\u3e2\u3c/sub\u3e, respectively) and corrections were proposed to achieve intrinsic rate laws from a model available in the literature. An analysis of the reactor performance was conducted and a nonlinear behavior was observed when the channel height (H) was varied. A point of maximum for the integral rate of NO and NO \u3csub\u3e2\u3c/sub\u3e consumption as a function of H was found (Δ \u3csub\u3eNO\u3c/sub\u3e of ∼2% and ∼-1% for H→2H→4H; Δ \u3csub\u3eNO \u3csub\u3e2\u3c/sub\u3e \u3c/sub\u3e of ∼46% and -8.5% for H→2H→4H). Additionally, the NO conversion decreased from ∼29% to ∼7% and the selectivity decreased from ∼85% to ∼80% (passing through a point of minimum at 2H) when the height was varied in the range H-4H. When comparing the results from the CFD simulations and the predictions of a plug flow model, deviations for NO conversion and selectivity increased with H (Δ \u3csub\u3emax\u3c/sub\u3e of ∼2% and ∼45%, respectively). \u3c/p\u3