In this work, the influence of experimental setup on derived kinetic data for the heterogeneous Boudouard gasification reaction is studied. A thermogravimetric analyzer (TGA) and a small-scale fluidized bed reactor (FBR) are used. The two systems differ basically in their fuel heating rates and fuel bed configurations. The kinetic study was performed in both reactors for the same temperatures and partial pressures of CO 2 at ambient pressure using same-batch fuel samples (biomass, brown coal, and petcoke). Kinetic data are reported, and the influence of the thermal history of the fuel particle prior to the char gasification process is discussed. In general, the activation energies derived from both systems are lower for the brown coal fuels as compared to the wood char fuels. This finding may be explained by the high ash content of the brown coal fuels with multiple catalytic components in the ash. Both experimental setups used in this study agree well in their results for the carbon conversion rate and kinetic parameters for fuels with low volatile content, whereas fuels with high volatile content show different results in the two experimental setups. This may be explained by the physical and chemical structure of the fuel particle not being changed significantly during the in situ pyrolysis prior to gasification for the low volatile fuels. The char properties of the high volatile fuels may differ significantly due to system dependent different heating rates and gas atmospheres during the in situ pyrolysis prior to gasification. Hence, the observed reactivity becomes system dependent. In conclusion, the results show that knowledge of the thermal history of the fuel particle prior to the gasification process is most important for the interpretation of kinetic data as well as for the design of experiments for generation of kinetic data.

A useable model for laminar free-surface jet evolution during flight, for both horizontal and vertical jets, is developed through joint analytical, experimental, and simulation methods. The jet’s impingement centerline velocity, recently shown to dictate stagnation zone heat transfer, encompasses the entire flow history: from pipe-flow velocity profile development to profile relaxation and jet contraction during flight. While pipe-flow is well-known, an alternative analytic solution is presented for the centerline velocity’s viscous-driven decay. Jet-contraction is subject to influences of surface tension (We), pipe-flow profile development, in-flight viscous dissipation (Re), and gravity (Nj = Re/Fr). The effects of surface tension and emergence momentum flux (jet thrust) are incorporated analytically through a global momentum balance. Though emergence momentum is related to pipe flow development, and empirically linked to nominal pipe flow-length, it can be modified to incorporate low-Re downstream dissipation as well. Jet contraction’s gravity dependence is extended beyond existing uniform-velocity theory to cases of partially and fully developed profiles. The final jet-evolution model relies on three empirical parameters and compares well to present and previous experiments and simulations. Hence, micro-jet flight experiments were conducted to fill-in gaps in the literature: jet contraction under mild gravity-effects, and intermediate Reynolds and Weber numbers (Nj = 5–8, Re = 350–520, We = 2.8–6.2). Furthermore, two-phase direct numerical simulations provided insight beyond the experimental range: Re = 200–1800, short pipes (Z = L/d · Re ≥ 0.01), variable nozzle wettability, and cases of no surface tension and/or gravity.

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Methane dry reforming presents a unique opportunity to simultaneously consume both methane and carbon dioxide and generate from them clean-burning synthetic fuels for mobile energy applications.