Intrinsic kinetics for rapid decomposition of methane in an aerosol flow reactor

Thermal ZnO dissociation in a rapid aerosol reactor as part of a solar hydrogen production cycle

“…Such reactors have been implemented by the Dow Chemical Company to produce tungsten carbide, by various researchers to produce other ceramics (e.g. NbB 2 , TiB 2 Þ, as well as by Dahl et al, to dissociate methane in a solar-thermal configuration [13][14][15][16][17][18][19][20]. Particles dispersed as an aerosol are, by definition, small ðo100 mmÞ [21].…”

“…The small size yields greater surface area for mass transfer, and increasing this area improves the overall rate of surface processes. Such particles have been shown to heat up extremely quickly, on the order of 10 5 K s À1 , when exposed to a high temperature surface [13,14]. This is on account of their ability to efficiently absorb the massive radiative heat flux from the hot wall.…”

Assessment of Natural Gas Splitting with a Concentrating Solar Reactor for Hydrogen Production

“…The first step in the calculations was to determine the methane conversion for various flow rates and temperatures using the entrained flow reactor model developed at the University of Colorado (CU) (Dahl, et al, 2002). Because variations in solar irradiance will affect the reactor operating temperature and conversion, a set single-pass conversion was maintained by varying the natural gas flow rate depending upon the solar irradiance.…”

Effect of seeding on hydrogen and carbon particle production in a 10 MW solar thermal reactor for methane decomposition

“…A number of research groups have developed models and simulations of solar methane decomposition reactors over the past few years: Dahl et al [16,17] developed a one-dimensional steady state model of indirectly heated seeded solar reactors, which they applied to an experimental solar reactor in order to extract kinetic parameters for the decomposition reaction and to perform a sensitivity study; Trommer et al [18] and Hirsch and Steinfeld [19] developed a model of a 5 kW directly heated seeded solar reactor, which they used to predict the temperature distribution and degree of chemical conversion achieved inside the reactor; Abanades and Flamant [20] performed a two-dimensional simulation of a 2 kW directly heated unseeded solar reactor using a commercial CFD package in order to determine the temperature distribution, species concentrations and overall degree of chemical conversion inside the reactor; Klein et al [21] performed Nomenclature C fraction Fraction of total carbon flow C fraction CH 4 Fraction of total carbon flow in methane flow C fraction fresh Fraction of total carbon flow in fresh particle flow C fraction products Fraction of total carbon flow in products flow C fraction seed Fraction of total carbon flow in seed particle flow C fraction wall Fraction of total carbon flow in wall carbon flow CH 4 i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 3 7 ( 2 0 1 2 ) 1 6 5 7 0 e1 6 5 8 0 a two-dimensional simulation of a directly heated seeded solar reactor using a commercial CFD package in order to determine the optimum seed particle concentration for heat transfer to the gas; Rodat et al [22] used a kinetic software for alkane transformations to study the decomposition of methane in an experimental 10 kW indirectly heated unseeded solar reactor; Maag et al [23] developed a onedimensional transient model of directly heated seeded solar reactors, which they used to study the effect of seeding and feed gas composition on the temperature distribution inside a 5 kW reactor; Ozalp and Kanjirakat [24] developed a CFD model of a directly heated seeded solar reactor, which they used to study the effect of seeding on methane conversion inside the reactor. Therefore, several models have already been developed which address the overall reaction and transport phenomena occurring inside solar methane decomposition reactors, with emphasis in particular on radiation transport phenomena in directly heated seeded reactors.…”