A drop-tube particle-entrained flow solar reactor applied to thermal methane splitting for hydrogen production. (1st August 2015)

• Record Type: Journal Article
• Authors: Abanades, Stéphane; Kimura, Hiroyuki; Otsuka, Hiroyuki
• Is Part Of: Fuel. Volume 153(2015)
• Page Start: 56
• Page End: 66
• Publication Date: 2015-08-01
• Subjects: Methane dissociation -- Pyrolysis -- Hydrogen -- Catalyst -- Carbon black -- Solar reactor; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2015.02.103
• Languages: English
• ISSNs: 0016-2361

Abstract

Abstract : Graphical abstract: Highlights: A particle-flow solar reactor was designed and operated for continuous H2 production. Feeding of carbon black catalyst was used to study the effect on methane decomposition. The entrained-flow drop-tube reactor was based on the indirectly-irradiated concept. Particle injection slightly improved the performances of the solar chemical reactor. CH4 conversion of 80% and solar-to-chemical efficiency of 5% were reached at 1350 °C. Abstract: A solar chemical reactor with continuous particle feeding in a tubular absorber has been designed and tested for CO2 -free hydrogen production from thermal methane decomposition. The entrained-flow reactor was operated on sun with carbon black particle injection in a stream of methane diluted in argon. The carbon particles are expected to act as a catalyst for the dissociation reaction and the indirect irradiation via an intermediate opaque tubular absorber results in a more uniform heating of the reactor volume and thus an easier reaction temperature control and determination. The effect of particle injection on the reactor performance was investigated as a function of the type of carbon black catalyst and characteristics, reaction temperature (1150–1400 °C), total volumetric gas flow rate and methane content in the feed gas (10–40%). Key measured performance outputs were CH4 conversion and H2 yield, C2 H2 outlet concentration, and solar-to-chemical reactor efficiency. The particle feeding did not drastically improve the methane decomposition rate and hydrogen yield, which can presumably be attributed to kinetic limitation due to short particle residence time in the high-temperature region. Likewise, the inlet methane mole fraction was not a primary influencing parameter. In contrast, the temperature and the gas flow rate strongly affected the methane decomposition rate.