Nitrate-base Molten Salts Platform as Thermal Energy Storage in Thermocline tank for Thermal Solar Pyrolysis Unit
Abstract
This research aimed to establish a thermal solar pyrolysis unit powered by molten salt flow from thermocline tank. Encapsulated graphene oxide in silica oxide (SiO2) was employed as a heat transfer agent to facilitate proper heat transfer inside the thermocline tank. Characterization was performed by scanning electron microscope (SEM), differential scanning calorimeter (DSC) and X-ray diffractometer (XRD) techniques to analyze textural morphology and heat storage capacity of the molten salt system. Encapsulation was found to be successful in providing stable matrix to house molten salt and graphene oxide nanoparticles. Addition of graphene oxide in the encapsulated molten salt was found to reduced melting temperature and crystallization temperature by almost 10%, which is help reduce energy required to activate the flow of molten salt inside the thermal system. Charge and discharge cycle were performed by varying molten salt flowrate into thermocline tank. Temperature monitored in axial direction revealed an increase in heat transfer efficiency as flowrate increased. Pyrolysis reaction was also tested using three different catalysts including zeolite, dolomite and kaolin to produce biooil, biochar and gas. An increase in temperature was found to favor gas production over zeolite catalyst due to presence of acidic sites. Optimized pyrolysis to produce 61.0% biooil was performed at 300 oC over kaolin catalysts.