Dataset Information

Catalyst-loaded micro-encapsulated phase change material for thermal control of exothermic reaction.

ABSTRACT: CO₂ methanation is a promising technology to enable the use of CO₂ as a resource. Thermal control of CO₂ methanation, which is a highly active exothermic reaction, is important to avoid thermal runaway and subsequent degradation of the catalyst. Using the heat storage capacity of a phase change material (PCM) for thermal control of the reaction is a novel passive approach. In this study a novel structure was developed, wherein catalysts were directly loaded onto a micro-encapsulated PCM (MEPCM). The MEPCM was prepared in three steps consisting of a boehmite treatment, precipitation treatment, and heat oxidation treatment, and an impregnation process was adopted to prepare a Ni catalyst. The catalyst-loaded MEPCM did not show any breakage or deformation of the capsule or a decrease in the heat storage capacity after the impregnation treatment. MEPCM demonstrated a higher potential as an alternative catalyst support in CO₂ methanation than the commercially available α-Al₂O₃ particle. In addition, the heat storage capacity of the catalyst-loaded MEPCM suppressed the temperature rise of the catalyst bed at a high heat absorption rate (2.5 MW m^-3). In conclusion, the catalyst-loaded MEPCM is a high-speed, high-precision thermal control device because of its high-density energy storage and resolution of a spatial gap between the catalyst and cooling devices. This novel concept has the potential to overcome the technical challenges faced by efficiency enhancement of industrial chemical reactions.

SUBMITTER: Takahashi T

PROVIDER: S-EPMC8024387 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Due to the instinctive temperature-dependent heat capacity of the Nano-Encapsulated Phase Change Material (NEPCM), there is a growing interest in the potential applications of such materials in heat transfer. As such, steady-state natural convection in a porous enclosure saturated with nanofluid using NEPCMs has been investigated in this study. The cavity is assumed to have constant hot and cold temperatures at the left and right vertical boundaries, respectively, and fully insulated from the bottom and top walls. Considering the Local Thermal Non-equilibrium (LTNE) approach for the porous structure, the governing equations are first non-dimensionalized and then solved by employing the finite element Galerkin method. The impact of different parameters, such as porous thermal conductivity (k s ), solid-fluid interface heat transfer (10 ≤ H ≤ 105), Stefan number (0.2 ≤ Ste ≤ 1), and volume fraction of nanoparticles (0.0 ≤ φ ≤ 0.05) on the patterns of the fluid and solid isotherms, streamlines and the contours of the heat capacity ratio, fusion temperature (0.05 ≤ θ f ≤ 1), local and average Nusselt numbers, and overall heat transfer ratio has been studied. It is shown that improving the porous thermal conductivity not only leads to an increase in the rate of heat transfer but also augments the fluid flow inside the cavity. For low values of the Ste, the rate of heat, transferred in the porous enclosure, is intensified. However, regardless of the amount of the Stefan number, the maximum rate of heat transfer is achievable when the non-dimensional fusion temperature is approximately 0.5. Employing NEPCMs in a highly conductive porous structure is more efficacious only when the phases are in the state of local thermal equilibrium. Nonetheless, the rate of heat transfer is higher when the Local thermal non-equilibrium is validated between the phases. Besides, for poor thermal conductivity of the porous medium like glass balls (LTE condition), adding 5% of the nano-encapsulated phase change materials to pure water can boost the rate of heat transfer up to 47% (for Ste = 0.2 and θ f = 0.5). This thermal investigation of NEPCMs shows in detail how advantageous are these nanoparticles in heat transfer and opens up an avenue for further application-based studies.

Project description:We probe the role of surface functionalization and physical properties of nanoinclusions in thermal conductivity enhancement during liquid-solid phase transition in a hexadecane-based phase change material (PCM). Hexadecane-based PCM is loaded with six different nanoinclusions: carbon black nanopowder (CBNP), nickel nanoparticles (NiNPs), copper nanoparticles, silver nanowires (AgNWs), multiwalled carbon nanotubes, and graphene nanoplatelets (GNPs). The nanoinclusions CBNP, NiNP, AgNW, and GNP are surface-functionalized with oleic acid. Nanoinclusion-loaded PCM showed a large enhancement in thermal conductivity, which was more prominent in the solid state. Interestingly, a maximum thermal conductivity enhancement of ?122% was observed in the solid state for the PCM loaded with 0.01 wt % CBNP. Higher thermal conductivity enhancement in the solid state is attributed to the formation of a nanocrystalline network structure during freezing of the PCM, consisting of a needlelike microstructure, which is confirmed by optical phase contrast microscopy. During solidification, the nanoinclusions are driven toward the grain boundaries, thereby forming a quasi-two-dimensional network of percolating structures with high thermal transport efficiency due to the enhancement of phonon-mediated heat transfer and near-field radiative heat transfer. Thermal conductivity increases with the increased loading of the nanoinclusions due to the formation of more interconnecting aggregates. Among the carbon-based nanoinclusions, the highest thermal conductivity enhancement is obtained for the PCM loaded with CBNP, which is attributed to the low fractal dimensions and volume-filling capability of CBNP aggregates. In the case of metallic nanoinclusions, the highest thermal conductivity enhancement is obtained for the PCM loaded with AgNW, which is due to the large aspect ratio of AgNW. The carboxylic group of oleic acid attached to the nanoinclusions is found to provide better steric stability with insignificant aggregation and improved thermal stability, which are beneficial for practical applications. Our results indicate that the initial thermal conductivity of carbon-based nanoinclusions has an insignificant role in the thermal conductivity enhancement of the PCM but the volume-filling capability of the nanoinclusion has a prominent role. The findings from the present study will be beneficial for tailoring the properties of nanoinclusion-loaded organic PCM for thermal energy storage and reversible thermal switching applications at room temperature.

Dataset Information

Catalyst-loaded micro-encapsulated phase change material for thermal control of exothermic reaction.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets