A Study Of Technology And Properties For Diatomite Matrix Thermal Storage Materials

With the development of new energy, this article concentrates on the preparationof a serious of microstructure thermal storage materials used at medium-hightemperature range. This kind of thermal storage material is consisted of inorganic,phase change material and thermal conductivity reinforced material. Among them,inorganic material is matrix phase, which is high temperature resistance and corrosionresistance. Phase change material is in charge of high latent heat and thermalconductivity reinforced material possesses high heat conductivity. The earth is rich indiatomite resources. Such type of materials has a high porosity and favorablestructural and thermophysical properties, and can therefore serve as the structuralmaterial for composite phase change materials. In this article, we first brieflyintroduces the structure and properties of diatomite, we then provide a state-of-the-artreview on the use of the diatomite as the structural material for encapsulating phasechange materials for thermal energy storage applications. Finally, furtherdevelopment in the area is discussed. The latent heat, energy density, phasecomposition, microstructure, heat conductivity and physical properties of thecomposite thermal storage material were studied by TG-DSC, XRD, SEM, BET anduniversal tester. At the same time, cycle life of the samples was evaluated. The mainachievements are as follows:1) Research and feasibility analysis on diatomite and its sintering character areconducted. Based on the principle of ceramic post sintering, phase change materialsusing at every operation temperature was chosen by high latent heat, low vapourpressure and good compatibility with diatomite. Graphite was used as thermalconductivity reinforced material.2) This article discussed the effects of formula, forming pressure, sinteringtemperature and holding time on physical characteristics and microstructure.3) The new thermal storage material could reach the demand of heataccumulation at medium-high temperature (150-1000oC). Energy density of someproducts is greater than550KJ/kg and heat conductivity is higher than4.0W/(m·k).compressive strength is not lower than10MPa. Phase change material distributed inthe porous structure of inorganic matrix. After tens of thousands of cold-hot cycles,there is still no any chemical reaction between inorganic matrix and phase changematerial and no leakage phenomenon. In the pilot test, this kind of thermal storagematerial is easy to large-scale industrial production.Both laboratory research and pilot amplification test results show that the composite heat storage material has good application prospect. The technology lay thefoundation of the industrial application of medium-high temperature heat storagematerial in the new energy storage and flue gas waste heat recycling industrial wasteheat recovery.