Binbin Bao

Inhibitory effect of MnCr2O4 spinel coating on coke formation during light naphtha thermal cracking

In this paper, MnCr2O4 spinel coating was fabricated on a HP40 alloy by pack cementation and subsequent thermal oxidation. The spinel coating was dense and uniform, and was applied to inhibit coke formation during light naphtha thermal cracking. Coking behaviors on the HP40 alloy and spinel coated alloy were compared under the same conditions. The anti-coking rate of the MnCr2O4 spinel coating exceeded 60% during light naphtha thermal cracking. Lots of filamentous coke formed on the uncoated HP40 alloy, but catalytic coke was completely inhibited on the MnCr2O4 spinel coated alloy resulting in a granular appearance of coke. Raman spectra analyses indicated that coke deposited on the surface of the spinel coating had a larger proportion of disordered carbon and amorphous carbon compared with that on the uncoated HP40 alloy.

Insight into a high temperature selective oxidation of HP40 alloy under a H2–H2O environment

In the present work, a selective oxidation process of HP40 alloy at 1050 °C under a H2–H2O environment were studied in detail by means of SEM, EDS, GD-OES, XRD, Raman spectra and XPS. The results revealed that selective oxidation of Mn and Cr elements was realized, and the oxide scale preferentially grew via grain boundary rather than via grain lattice. The oxide scales were composed of a majority of MnCr2O4 spinel and a spot of Cr2O3 throughout the oxidation process. Mn existed in the form of Mn2+ ions on the surface, while Cr existed in various species. Metal hydroxides appeared on the surface approved by spectra of the O 1s region, and the relative amount of them decreased with oxidation time.

3D-printed air-blast microfluidic nozzles for preparing calcium alginate microparticles

Microfluidic technologies have emerged as a promising route for precision fabrication of uniform particles. Equipment required for a traditional microfluidic device manufacturing process is expensive and production efficiency is low. Its also difficult to separate a surfactant and continuous phase impurities from particles prepared by a liquid–liquid two-phase shear method. A novel air-blast microfluidic nozzle fabricated using low-cost and efficient 3D printing technology was proposed to prepare calcium alginate particles. Effects of control parameters and solution composition on particle diameters and homogeneity were systematically investigated. Results showed that inlet air pressure has the most significant impact. A nozzle with an outlet diameter of 300 μm can produce particles with diameters ranging from 360 μm to 2100 μm. Coefficients of variation (CV) range from 5.3% to 2.2%. For the same diameter particle prepared, a smaller nozzle outlet had a narrower particle diameter distribution and needed lower inlet air pressure. This method can be used to handle high viscosity solutions and high concentrations of solutions with insoluble solid particles. The prepared particles can be used in biological and pharmaceutical fields.

Performance and Routes of Nitrogen Oxide Formation of MILD Forward-Flow Furnace with Reflector

AbstractHigh-momentum jets, which are the key parameter to achieve moderate or intense low-oxygen dilution (MILD) combustion may lead to insufficient residence time and high CO emissions, especiall...