The unknown NOx distributions inside large-scale CFB (circulating fluidized bed) boilers have always hindered the economy of the SNCR (selective non-catalytic reduction) process. In this study, field tests were carried out on a typical 300 MW CFB boiler, where multi-level 316 L-made probe and Ecom-J2KN/Testo 350 analyzers were used to perform detailed two-dimensional distributions of flue gas composition at SNCR inlets for the first time. The penetration depth inside the horizontal flue pass was up to 7 m. The NOx distributions were analyzed in detail combining with the auxiliary test in the dilute phase zone. Key results show that the average O2 concentrations in #A and #C regions were 6.52% and 0.95%, respectively. The vertical NOx distributions of #A and #C SNCR inlets were similar, showing a trend of first increasing and then decreasing with peak value all appeared at 5 m depth, while the NOx distribution of #B SNCR inlet was basically increasing. Some local areas with extremely high NOx concentration (over 2000 mg/m3) were observed near the inclined edge of SNCR inlets, which has never been reported before. Based on this, the optimization of urea injections was conducted, which could save 15.7% of the urea solution consumption while ensuring ultra-low emission of NOx.
A series of Cu‐containing trimetal mixed oxides supported nano‐Au catalysts were prepared and characterized by XRD, N2 sorption, elemental analysis and H2‐TPR. Then, their catalytic performance was firstly investigated in the selective oxidation of glycerol with 3% H2O2 or O2 as oxidants. It was found that both the elemental components of mixed oxides and the types of oxidant influenced remarkably the catalytic performance of the supported catalysts and the product distributions. Under the optimal reaction conditions, the highest yield of main product glyceric acid reached 66.5% over CuMnAl mixed oxide supported nano‐Au catalyst in the presence of O2. Moreover, the catalyst could be reused several times. In addition, the catalyst was further used in the selective oxidation of benzyl alcohol and cyclohexanol, and the best yield of benzaldehyde and cyclohexanone were 72.5% and 96.0%, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.