Thermal conductivity of the benzyltoluene-based liquid organic hydrogen carrier system and its hydrogenated and oxygenated derivatives

This work investigates the thermal conductivity λ c of the benzyltoluene-based liquid organic hydrogen carrier (LOHC) system relevant for autothermal process concepts. Besides the three regioisomers of the dehydrogenated benzyltoluene (H0-BT), their corresponding hydrogenated and partially oxidized derivatives perhydrobenzyltoluene (H12-BT) and methylbenzophenone (oxo-H0-BT) are studied. Using a guarded parallel-plate instrument, λ c is determined at atmospheric pressure and temperatures between (278.15 and 358.15) K with an expanded relative uncertainty of 2 %. The experimental λ c data increase from H12-BT via H0-BT to oxo-H0-BT and show no significant influence of regioisomerism for each class. For selected binary H0-BT/H12-BT mixtures, a non-linear behavior for λ c as a function of amount fraction was found, while λ c of binary H0-BT/oxo-H0-BT mixtures agrees with the values for the pure substances. An available prediction model for λ c of cyclic hydrocarbons represents the measurement results for the H0-BT and H12-BT regioisomers reasonably well, yet shows shortcomings in case of the oxo-H0-BT regio-isomer. • Study of benzyltoluene (BT)-based LOHC system relevant for autothermal processing. • Measurement of λ c by parallel-plate method from (278–358) K with 2 % uncertainty. • Minor influence of regioisomerism on λ c for H0-BT, H12-BT, and oxo-H0-BT components. • Non-linear trend for λ c as a function of amount fraction for H0-BT/H12-BT mixtures. • Prediction model describes λ c adequately only for H0-BT and H12-BT regioisomers.