Initial Experimental and Theoretical Investigation of Solar Molten Media Methane Cracking for Hydrogen Production

Abstract

a b s t r a c tA conventional wisdom about the progress of physics holds that successive theories wholly encompass the domains of their predecessors through a process that is often called "reduction." While certain influential accounts of inter-theory reduction in physics take reduction to require a single "global" derivation of one theory's laws from those of another, I show that global reductions are not available in all cases where the conventional wisdom requires reduction to hold. However, I argue that a weaker "local" form of reduction, which defines reduction between theories in terms of a more fundamental notion of reduction between models of a single fixed system, is available in such cases and moreover suffices to uphold the conventional wisdom. To illustrate the sort of fixed-system, inter-model reduction that grounds inter-theoretic reduction on this picture, I specialize to a particular class of cases in which both models are dynamical systems. I show that reduction in these cases is underwritten by a mathematical relationship that follows a certain liberalized construal of Nagel/Schaffner reduction, and support this claim with several examples. Moreover, I show that this broadly Nagelian analysis of inter-model reduction encompasses several cases that are sometimes cited as instances of the "physicist's" limit-based notion of reduction.

Hydrogen production via methane pyrolysis in a liquid metal bubble column reactor with a packed bed

“…Martynov et al [6] and Gulevich et al [7] proposed a hydrogen production process by using heavy liquid metal coolants (Pb-Bi) while the methane for the pyrolysis reaction is fed to the lower section of a reaction vessel. Paxman et al [8] published theoretical investigations of methane cracking in a bubble column reactor with different injector designs (6 mm and 3 mm tube, 7 µm and 0.5 µm porous sparger). In their most recent study they presented preliminary experimental runs in a blank tubular reactor without applying liquid metal.…”

Development of methane decarbonisation based on liquid metal technology for CO2-free production of hydrogen

“…Martynov et al [18] proposed a methane pyrolysis process for hydrogen production by direct-contact heat transfer from heavy liquid metal coolants (Pb-Bi). Paxman et al [19] have presented their preliminary experimental and theoretical investigations on methane cracking for hydrogen production with a molten metal reactor. Their ultimate goal is to build and test a prototype solar reactor with molten metal for methane cracking.…”

“…6) was a very important issue when metallic materials are used for the construction of the reactor. In the case of tin, the preferred material from its chemical and fluid-mechanics behaviour [16] [17] [19] [21], the corrosion rates for steels at the temperature of the process are very high, of the order of 30 μm/h at 700 °C [22]. More sophisticated materials such as tungsten and molybdenum have been identified as structural materials, as well as quartz or alumina.…”

Catalytic molten metals for the direct conversion of methane to hydrogen and separable carbon

“…The only commercially practiced processes use gasphase reactions in thermochemical or plasma reactor systems (5) to produce specialty carbons; however, CH 4 pyrolysis has not been used commercially specifically for H 2 production. Steinberg (6) and others (7)(8)(9)(10)(11)(12)(13)(14)(15) have proposed using inert molten metals as thermochemical reaction media and as a heat transfer fluid for pyrolysis of CH 4 . In molten metals, the low-density carbon produced by gas-phase pyrolysis at high temperature floats to the surface of the melt where it can be removed.…”