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Title: Dynamics of a sodium heat pipe natural gas reformer

Thesis/Dissertation ·
OSTI ID:5514903

Energy transmission via a chemical heat pipe is based on reversible endothermic and exothermic reactions. One application of the chemical heat pipe concept is the SOLTHERM process, which utilizes solar energy from solar collectors to drive the endothermic methane-steam reforming reaction and delivers chemical energy to users through pipelines and the reverse exothermic methanation reaction. Solar fluxes at central receivers are as high as 1 MW/m/sup 2/, a factor of ten greater than utilized by the heat-transfer limited reforming reactor. Accordingly, flux transformers such as sodium heat pipes must be used to supply energy to the reactor. A sodium heat pipe natural gas reformer pilot plant has been designed, constructed and operated to study the performance of a commercial scale, simulated solar energy reformer. The concept of a sodium heat pipe reformer has been shown to be feasible by the pilot plant tests. Complete conversion of methane is achievable within current reactor dimensions. Heat transfer rates from heat pipe to catalyst and within catalyst bed itself are shown to be large and estimable from existing heat transfer correlations. Existing reformer computer model simulate the reactor closely, as shown by a comparison of experimental and calculated data. Large extent of catalyst breakup was observed, possibly caused by heat pipe thermal elongation and contraction. A layer of catalyst powder was found on the heat pipe wall, reducing heat transfer to the catalyst bed. Hydrogen permeation into the heat pipe was a problem, hindering energy transport to the reactor upper section. A thermal regeneration technique was developed successfully to expel trapped hydrogen from the heat pipe interior, but is very time-consuming and expensive.

Research Organization:
Houston Univ., TX (USA)
OSTI ID:
5514903
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English