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Influence of Reaction Reversibility on the Interpretation of Delplots of the Parallel-Series Reaction Network

Abo-Ghander, Nabeel S., Klein, Michael T.
Energy & fuels 2019 v.33 no.2 pp. 1444-1449
feedstocks, fuels, models
The use of the Delplot analysis to interpret the experimental results from the parallel-series reaction network A→k1B→k3C; A→k2D under the influence of reaction reversibility was examined. A reactor model was used to test two experimental feeds, one with zero product species concentrations and the other with non-zero product species concentrations. The equilibrium constants K₁, K₂, and K₃ were varied between 0.2 and 1.5 for each reaction in the network. When CA₀ = 2.0 M and CB₀ = CC₀ = CD₀ = 0 M, it was found that reversibility did not change the analysis provided by the first-rank Delplots; i.e., species “B” and “D” are primary, while species “C” is non-primary. When CA₀ = 2.0 M and CB₀ = CC₀ = CD₀ = 0.5 M, it was found that the effect of the reversibility altered the information provided by Delplot analysis. For instance, the first-rank Delplot classified species “B” as a primary product when K₁ ≥ 0.5 but non-primary when K₁ = 0.2. A similar conclusion was also obtained for species D; i.e., species “D” was a primary product when K₂ ≥ 0.5 but non-primary when K₂ = 0.2. For species “C”, it was found that species “C” is primary at high K₃ but non-primary at low K₃. In summary, when the feed has non-zero product concentrations and the reaction network contains reversible reactions, the species ranks suggested by standard Delplot analysis can be disguised. This would suggest that extra care should be practiced when Delplot analysis is used for reaction networks in which high reversibility may exist.