Investigation on thermal characteristics of novel composite sorbent with carbon coated iron as additive

Carbon coated iron and expanded natural graphite are selected as the additives in developing novel consolidated composite strontium chloride, which is attempted to improve heat and mass transfer performance. Due to anisotropic characteristics, both disk and plate samples are investigated which are parallel and perpendicular to compression direction respectively. It is worth noting that thermal conductivity of composite sorbent increases with the increase of density and the decrease of mass ratio whereas permeability shows a reverse trend. Results demonstrate that the highest thermal conductivity of composite strontium chloride with carbon coated iron could reach 2.95 W m−1 K−1, which is improved by 14 times when compared with granular salt. Permeability of composite sorbent ranges from 1.2 × 10−9 m2 to 4.5 × 10−14 m2 when density is in the range between 400 kg m−3 and 600 kg m−3. Sorption characteristic of composite sorbent with carbon coated iron is also investigated and compared with that not adding carbon coated iron. Under the condition of −10 °C evaporation temperature, sorption reaction rate of composite sorbent with carbon coated iron is better than that without carbon coated iron due to the improved mass transfer performance. Sorption rates of composite sorbents are almost the same when evaporation temperature reaches 10 °C.