Title

Solar Thermocatalytic Decomposition Of Ammonium Sulfate

Abstract

Thermal decomposition of ammonium sulfate, (NH 4) 2SO 4, constitutes one of the primary steps in the sulfur-ammonia solar thermo-photochemical water splitting cycle under development at FSEC. In this paper, mechanisms and distribution of (NH 4) 2SO 4 decomposition products, namely, sulfur dioxide (SO 2) and/or sulfur trioxide (SO 3) were investigated using thermogravimetric/differential thermal analyses (TG/DTA) coupled with mass spectrometric analysis (MS) technique. Results indicate that both the sample holder material of construction and heating rates strongly influence the reaction pathways and products of (NH 4) 2SO 4 decomposition reaction. With a ceramic sample holder, two sequential reaction stages are present, i.e. de-ammoniation and dehydration; and decomposition of ammonium pyrosulfate, (NH 4) 2S 2O 7, to ammonia (NH 3) and disulfuric acid (H 2S 2O 7). Temperatures at which de-ammoniation/dehydration and pyrosulfate decomposition occur depend on the sample heating rates. At high heating rates, the decomposition temperatures are higher and reaction mechanisms more complicated. No N 2, O 2, SO 3 or sulfuric acid (H 2SO 4) was present as the products of (NH 4) 2SO 4 decomposition. Therefore, NH 3 disassociation is unlikely and the S-NH 3 photo-thermochemical water splitting can be carried out as a closed cycle. The use of a platinum sample holder inhibited the dehydration reaction and gave completely different reaction mechanisms.

Publication Date

12-1-2007

Publication Title

American Solar Energy Society - Solar 2007: 36th ASES Annual Conf., 32nd National Passive Solar Conf., 2nd Renewable Energy Policy and Marketing Conference: Sustainable Energy Puts America to Work

Volume

1

Number of Pages

107-114

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

Socpus ID

84867889547 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84867889547

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