Paraffin Mixtures Research Articles

Investigating the gelling behaviour of ‘waxy' paraffinic mixtures during flow shutdown

AbstractThe flow of waxy or paraffinic crude oils in a pipeline could be shutdown for a variety of reasons, resulting in their cooling and subsequent gelling. Gel formation from a multicomponent wax‐solvent mixture during flow shutdown was investigated experimentally and analyzed with a transient heat‐transfer model based on the moving boundary problem formulation. The gelling experiments were performed with a 0.10 g/g wax‐solvent mixture in a flow‐loop apparatus, following the formation of a steady‐state deposit layer in turbulent flow regime, at two initial wax‐solvent mixture temperatures, with a constant coolant temperature, and for different shutdown times. The gel formation was found to be a fast process, which continued until the gel fully occupied the deposition tube. Gas chromatographic analyses of the deposit samples (under sheared cooling) and the gel samples (under static cooling during flow shutdown) indicated significant differences in the composition and the total wax content. The deposit samples showed an enrichment of heavier paraffins, whereas the composition of gel samples was comparable to that of the original wax‐solvent mixture. The predictions from the transient model showed that a lower initial oil temperature, a lower coolant temperature, and a smaller pipe diameter would result in a faster blockage of the pipe. The predictions from the moving boundary problem formulation agreed well with the flow shutdown data, which further confirmed that the solid and gel formation from wax‐solvent mixtures is modelled satisfactorily as a heat transfer process.

Preparation of PMMA/SiO2 PCM microcapsules and its thermal regulation performance on denim fabric

PurposeThis study aims to evaluate the thermal performance of phase change materials (PCMs) microcapsules (MCs) attached using SiO2 microspheres and investigate the thermal regulation effect on the coated denim fabric.Design/methodology/approachThe PCM microcapsule was prepared by in situ polymerization using a mixture of solid paraffin and butyl stearate as core material (CM) and methyl methacrylate as a monomer. The SiO2 microparticles were attached to the outer layer of the membrane to enhance the thermal performance of MCs. The morphology, chemical structure, latent heat storage and thermal resistance of MCs were characterized. PCM MCs were coated on the denim fabric and thermo-gravimetric analysis was conducted; thermal insulation and thermal infrared imaging performance of the coated fabrics were also investigated.FindingsThe diameters of SiO2 particles and PCMs MCs were 300-500 nm and 1 μm, respectively. SiO2 was wrapped on single-wall PCMs MCs with the mass ratio of 1:5. With the addition of SiO2, the phase transition temperature range of MCs increased from 34°C to 39°C, and the endothermic and exothermic latent heat decreased by 5.35 J/g and 10.07 J/g, respectively. The degradation rate of MCs was significantly slowed down at high temperature. The denim fabric coated with MCs revealed thermal regulation property. After absorbing heat, the MCs slowed down the rate of heat loss and extended the heat release time.Research limitations/implicationsThe phase transition temperature of the composite CM was wide, and the latent heat storage was reduced. The addition of SiO2 particles can significantly slow down the rate of heat loss, but it further reduces the latent heat storage performance.Practical implicationsThe method developed provided a simple and practical solution to improve the thermal regulation performance of fabrics.Originality/valueThe method of adjusting the phase transition temperature range of the composite CM is novel and many applications could be found in preparation of PCMs and thermal management.

Исследование причин снижения эффективности депрессорной присадки при перекачке парафинистых нефтей

The purpose of the research is to find out the reasons for the decrease in the effectiveness of the depressor additive DPN-1 as oil flows through the pipeline. The objects of the research are a mixture of paraffinic oils entering the Usa – Ukhta oil pipeline, either treated or untreated with DPN-1, as well as its mixture with highly-refined oil pumped from the Chikshino crude oil delivery and acceptance point. To achieve this goal, the rheological properties of oil were monitored at the main US oil pumping station, Chikshino and Ukhta-1 oil pumping stations; laboratory studies on the rheological properties attributed to simulated mixtures, compiled taking into account the volumes of oil delivered by various oil producers; and monitoring of the rheological properties of point samples of oils as they flow through the pipeline. The serial experiments resulted in establishing that the key factor in reduced efficiency of the DPN-1 additive used in the paraffinic oil mixture is the high pour point oil pumped from the Chikshino crude oil delivery and acceptance point (the share of which is 10 % of the total pumping volume).

New renewable raw materials for thermal energy storage

The thermal behavior of materials based on the renewable raw resource, beeswax, was studied to evaluate their potential as phase-change materials, PCMs, for latent heat thermal energy storage, LHTES. Beeswax, transesterified beeswax methyl esters and mixtures of beeswax with paraffin were studied. Additionally, waste vegetable cooking oil, a widely available and underused renewable raw material, was fully hydrogenated and the product, and its mixtures with beeswax, were investigated as candidates to PCMs. Transesterified beeswax shows an increase of about 15% in melting/crystallization enthalpies relative to the already suitable beeswax. In addition, the phase transitions take place at a 10 °C higher temperature range. These characteristics, and the minimal undercooling for crystallization, make both samples good PCM candidates. The addition of beeswax to hydrogenated waste cooking oil was found to be efficient in promoting the formation of the most stable triacylglycerides polymorph, making mixtures of these two renewable raw materials promising candidates for LHTES. Beeswax + paraffin mixtures, with 40% beeswax content, show near ideal thermal behavior for a PCM, while decreasing the amount of the crude derivative. Additionally, the volume change upon melting, one of the major problems of paraffins as PCMs, is considerably less for this mixture (about 50%).

Titelbild Chem. Ing. Tech. 5/2020

Chemie Ingenieur TechnikVolume 92, Issue 5 p. 489-489 Cover PictureFree Access Titelbild Chem. Ing. Tech. 5/2020 First published: 23 April 2020 https://doi.org/10.1002/cite.202070501AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract Flexible and scalable electrochemical microreactor for the electrification of chemistry. Copyright: Fraunhofer Institute for Microengineering and Microsystems IMM Organic electrochemistry is a more and more emerging technology for the environment-friendly production of chemical compounds driven by the search for ”green” synthesis routes, the emergence of novel synthesis strategies and the ambition of for a direct utilization of sustainable electric energy. Microstructured electrochemical reactors have special advantages over conventional ones helping to address still existing challenges. Moreover, there is a request for flexible reactor concepts. So, a novel flexible and scaleable electrochemical microreactor has been designed, realized, and validated by application to three different representative electrosyntheses: synthesis of tailor-made mixtures of paraffins by Kolbe electrolysis, cation flow method, and synthesis of peroxodicarbonate. A. Ziogas*, C. Hofmann, S. Baranyai, P. Löb, G. Kolb, Chem. Ing. Tech. 2020, 92 (5), 513–524. DOI: https://doi.org/10.1002/cite.201900140 Volume92, Issue5Special Issue: ReaktionstechnikMay 2020Pages 489-489 RelatedInformation

Fuel purpose hydrocracking of biomass based Fischer-Tropsch paraffin mixtures on bifunctional catalysts

Two biomass-based Fischer-Tropsch paraffins comprising of 16–46 and 11–45 carbon number range alkanes were hydrocracked over zeolite mordenite and tungstated-zirconia-supported platinum catalysts. The reaction was carried out in the temperature range of 300–350 °C, at 40 bar pressure and hydrogen/hydrocarbon volume ratio of 600. The liquid hourly space velocity was varied in the range of 0.5 and 2.0 h−1. The yields and the compositions of gas, gasoline, jet and gas oil fractions were studied as function of process parameters and catalyst properties. The conversion of paraffin components having more than 21 carbon atoms was determined. Under identical reaction conditions near the same conversions were obtained over the two catalysts. However, the feedstock composition significantly influenced the result of the hydrocracking process. Regularly lower conversions and higher middle distillate yields (jet + gas oil) were obtained for feedstock characterized by 11–45 carbon number range. The weaker acidic tungstated-zirconia-supported platinum catalyst was more suitable for production of engine fuels than the stronger acidic mordenite catalyst. Over platinum/tungstated-zirconia catalyst lower gas (0.5–15.0 wt%) and higher middle distillate yields (14.7–43.0 wt%) were obtained than over platinum promoted mordenite catalyst. The formation and diffusion of isoparaffins is more favored in mesopores than in micropores, therefore more isoparaffin was formed over the mesoporous tungstated-zirconia-supported platinum catalyst than over the microporous mordenite. In the micropores diffusion constraints prevailed promoting the formation of gaseous products.

Conversion of polyethylene waste into clean fuels and waxes via hydrothermal processing (HTP)

The exponential growth of plastic production and a low recycling rate (<9%) over the last 60 years have resulted in vast plastic waste accumulation in landfills and the environment. About 40% of the 350 million tons of global plastic waste generated in 2015 was polyethylene (PE). Converting PE waste into useful products can help reduce PE waste accumulation. Hydrothermal processing (HTP) of PE into oils was studied previously; however, comprehensive reaction pathways were not reported, and the products were not evaluated for potential fuel and wax applications. In this study, various PE wastes were converted via HTP at 425–450 °C for reaction times of 0.5–4 h into clean waxes or ultra-low sulfur fuels. Two-dimensional gas chromatography (GC×GC) and FTIR were used for determining the chemical compositions of the products. A mixture of paraffin and α-olefin waxes was obtained with a high yield, 97 wt. %, at 425 °C and 30 min. The highest oil yield, 87 wt. %, for producing fuels was obtained at 425 °C and 2.5 h. The diesel fraction (HTP diesel) met all requirements for No. 1-D ultra-low sulfur diesel and had a high cetane number of 61 and a low aromatic content of 18 vol. %. Mixtures up to 50 vol. % of HTP diesel in commercial diesel also met all requirements for No. 2-D ultra-low sulfur diesel. Comprehensive reaction pathways for PE conversion were inferred from detailed GC×GC analyses of reaction intermediates. The HTP method is more energy-efficient and has lower greenhouse gas emissions than incineration and pyrolysis, and is a promising method for reducing PE waste accumulation.

Novel Flexible Electrochemical Microreactor and its Validation by Three Model Electrosyntheses

AbstractA novel flexible electrochemical microreactor has been developed. Flexibility is reached by a modular design, suitability for a broad process parameter range including high pressure operation, and accessibility of production scale. Selected reactor aspects have been validated by applying the reactor to three different electrosyntheses: synthesis of tailor‐made mixtures of paraffins by Kolbe electrolysis, cation flow method, and synthesis of peroxodicarbonate. High conversion rates, yields, selectivities, and Faraday efficiency levels have been observed, showing precise process control.

Preparation of Sn–58Bi solder powder by shearing liquids into complex particles

In the present work, Sn–58Bi solder powder that had a core–shell structure with particle diameter between 1.0 and 30.0 μm was prepared by shearing liquids into complex particles (SLICE). Molten Sn–58Bi alloys were dispersed into spherical microstructure coated with organic matter using high-speed mechanical agitation and dispersant, which was a mixture of paraffin and polyethylene glycol (PEG). Microstructural evolution of particles was investigated under variations in stirring rate (5000 rpm, 10,000 rpm, or 15,000 rpm) and cooling methods (air cooling, water cooling, or ice water cooling). The optimal Sn–58Bi solder powder that had a diameter ranging from 1.9 to 27.6 μm was obtained in a stirring time of 5 min, a stirring rate of 15,000 rpm, and a cooling method of ice water cooling. Such microparticles with favorable size are promisingly used in electronic industrial applications.

Synthesis and Characterization of the Paraffin/Expanded Perlite Loaded With Graphene Nanoparticles as a Thermal Energy Storage Material in Buildings

Abstract Various properties of the paraffin have made them compatible to be incorporated in the building materials for improving the latent heat storage capacity of the building envelope. However, the poor thermal conductivity of the paraffin reduces their thermal performance and hence limits their direct application/incorporation in the buildings. In this study, composite mixtures of paraffin and expanded perlite (EP) with an equal weight percent of 49.5 and 47.5, loaded with 1% and 5% of graphene nano-platelets, respectively, were synthesized. The developed samples were characterized uncycled and after 2000 thermal cycles. The results indicate that phase change material (PCM)/expanded perlite/graphene nano-platelets composite shows a significant increment in the thermal conductivity, reduction in the latent heat storage capacity, and a small weight loss. The heat storage/release test depicts that the phase change material/expanded perlite/graphene nano-platelets-5 shows 1.66 and 2.5 times faster heat storage/release rate than phase change material/expanded perlite/graphene nano-platelets-1 and paraffin, respectively. There is no significant change noted after 2000 thermal cycles in phase change material/expanded perlite/graphene nano-platelets-5 and phase change material/expanded perlite/graphene nano-platelets-1 samples, suggesting long-term reliability of the composite PCM. Additionally, thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR) testing were also conducted and the results suggest high thermal reliability and good chemical compatibility. These analyses suggest that the phase change material/expanded perlite/graphene nano-platelets composite can become a potential candidate for thermal energy storage.

Predicting wax appearance temperature and precipitation profile of normal alkane systems: An explicit co-crystal model

Wax precipitation is a major flow assurance issue for petroleum production, oil blending, downstream processing, and oil products usage. While numerous thermodynamic models have been proposed to calculate wax appearance temperature (WAT) and precipitation profile at temperatures below WAT, the existing models are correlative in nature and fail to comply with phase behavior experimentally observed for wax precipitation. This work presents a predictive thermodynamic model for wax precipitation based on an explicit co-crystal formation assumption for precipitated wax, a treatment consistent with experimental findings. With a simple Flory-Huggins expression accounting for the liquid phase nonideality and the treatment of lamella structure for wax precipitation below WAT, the model satisfactorily predicts WAT at low pressures for multicomponent paraffin mixtures and wax precipitation amounts and contents as the temperature drops below WAT.

Research on the application of green energy-saving and environmental protection decoration materials in building decoration construction

The thesis takes refined solid paraffin, liquid paraffin and dodecyl alcohol molten mixture as environmentally friendly decorative materials. By adding chlorinated paraffin, graphite fibre and other materials to improve its phase change sensitivity, high-performance composite phase change materials are prepared for use in construction under construction. Combining high-performance composite phase-change materials and interior decoration energy-saving and environmentally friendly decorative material systems, a set of indoor self-temperature-adjusting energy-saving and environmentally friendly decorative material systems based on composite phase-change materials was designed. The green energy-saving and environment-friendly decorative material system can cause the phase change material to undergo phase change to absorb or release heat when the season changes or the indoor temperature fluctuates, thereby realising self-adjustment of the indoor temperature and reducing energy consumption for cooling or heating. It is practical and efficient when combined with decorative ceilings and environmental protection integrated internal partition wall panels for interior decoration.

Комплексне дослідження процесів накопичення теплової енергії при фазових перетвореннях органічних акумулюючих матеріалів з нано- та мікрочастинками металів

The possibility of improving battery performance heat from accumulating phase change material. Parameters studied structural phase transitions paraffins and mixtures of micro - and nanoparticles of metals optical method that is non-contact and non-destructive method of mapping crystallization processes for the analysis of thermodynamic properties and interactions in molecular chains of the samples. As source material used paraffin brand T3. To correct systematically analyze the impact of these powders on the dynamics of phase transitions in a mixture of paraffin with a specific powder, was originally studied structural and vibrational properties of the initial powders. The temperature dependence of Raman spectra and structural parameters for pure waxes and their mixtures with metallic heat conductive fillers. It was established that the addition of the latter does not affect the frequency bands of the main provisions of characterizing variations in paraffin and paraffin improves heat conducting properties of the excipients. Investigated enhance thermal conductivity, more even distribution of thermal field and lowering the temperature of the main phase transitions in reinforced heat accumulating substances. Established and explained the difference in the dynamics of structural phase transitions net (source) paraffins and reinforced heat conductive fillers. Key words: accumulator of heat, accumulating material, phase transition, metal nanoparticles, Raman spectroscopy

Liquid chromatography–electrospray ionization-tandem mass spectrometry for the determination of short-chain chlorinated paraffins in mixed plastic wastes

Wastes containing short-chain chlorinated paraffins (SCCPs) at concentrations above the Basel Convention low persistent organic pollutant content (LPC) values must be destroyed or irreversibly transformed in an environmentally-sound manner. Here, we developed a novel liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MSMS) method for determining the concentrations of SCCPs in mixed plastic wastes. Major SCCP homologues were identified with good separation and peak width by using a low-hydrophobicity cyano-propyl column and a mobile phase consisting of water and methanol containing ammonium acetate. Precursor ion peaks corresponding to the formation of stable SCCP homologue-adducts were observed, followed by two intense product ion peaks corresponding to separation of the adduct into acetate and the homologue. The formulation of a novel calibration standard with known SCCP homologue percentage composition supported the development of our novel mass spectrometric technique. The results obtained with the LC-ESI-MSMS system were quantitatively and qualitatively comparable with those obtained with a high-resolution mass spectrometry (HRMS) coupled to gas chromatography (GC) system. Homologue concentrations determined by LC-ESI-MSMS were significantly correlated with those determined by GC-HRMS in samples of commercial chlorinated paraffin mixture and mixed plastic waste, respectively. As a complementary technique to the highly accurate, but less versatile GC-HRMS approaches, the SCCP analysis by LC-ESI-MSMS is a practical way to identify mixed plastic wastes containing SCCPs at concentrations higher than the Basel Convention's LPC value.

Microstructural design and thermal characterization of composite diatomite-vermiculite paraffin-based form-stable PCM for cementitious mortars

The thermal performance of cementitious mortars can be improved with the use of form-stable phase change materials (PCMs) consisting of a solid-liquid paraffin mix impregnating diatomite in a diatomite-vermiculite mineral system. The present study includes designing, developing, and characterizing a novel PCM based on a combination of diatomite and calcined, expanded vermiculite, and an optimized paraffin system consisting of a mixture of solid paraffin and naphthenic oil. The diatomite is expected to store the paraffin and wrap the vermiculite particles, increasing the amount of stagnant air. X-ray fluorescence is used to assess the chemical composition of the diatomite and vermiculite. Differential scanning calorimetry (DSC) and Fourier transform infraredspectroscopy (FT-IR) measurements are used to characterize the paraffin mixes aimed at optimum performance for residential and commercial buildings. PCM samples made from paraffin and diatomite (PCM1), vermiculite (PCM2), and a mix of diatomite and vermiculite (PCM(1 + 2)) are characterized by scanning electron microscopy and FT-IR. Cement mortars are prepared in the volume ratios of 1:4 cement:sand (reference mortar), 1:4:1 cement:sand:diatomite, 1:4:1 cement:sand:vermiculite, and 1:4:1 cement:sand:PCM. The thermal properties of these materials are evaluated. The DSC results of the paraffin mixtures indicate that 20% naphthenic oil is the ideal concentration in the paraffin mixture to optimize the solid-liquid temperature (57.45 °C) and latent heat for building applications (159.42 J/g). All PCMs have reduced thermal conductivities compared to the reference mortar (1.47 W/m·K), with the lowest being associated with the PCM(1 + 2) sample (0.82 W/m·K). The PCM(1 + 2) sample also presents an improved combination of diffusivity, volumetric heat capacity, and thermal resistivity. The simultaneous addition of vermiculite and diatomite to the PCM composition improves the thermal properties, while maintaining the basic characteristics such as chemical and structural stability.

LILIN AROMATIK MINYAK ATSIRI KULIT BATANG KAYU MANIS (Cinnamomum burmannii) SEBAGAI REPELEN LALAT RUMAH (Musca domestica)

This research was aimed to create aromatic candle, infused with cinnamon (Cinnamomum burmanii) bark essential oil, which is a potential repellant for house fly (Musca domestica). The distillation of akar wangi samples was carried out at the Spice and Aromatic Research Unit by vapor distillation method for 9-12 hours. The aromatic candles were based on a mixture of solid paraffin and stearin in a 2:8 proportion, respectively, enriched with fragrant root bark essential oils with 5 formulas, namely F1 (placebo), F2 (fixative), F3 (1% essential oil), F4 (2% essential oil), and F5 (3% essential oil). The repellency test was carried out by inserting 20 house flies in a of 50x50x50 cm container that contains a lighted aromatic candle according to the doses mentioned above, and shrimp scalps located 15 cm from the candle that functions as a bait. The calculated parameters were the hourly number of flies that were allured to the bait for 6 hours, which were related to the candle’s repellency and the house fly’s preference of candle. The repulsion ability result were 89.724%, 75.28%, 68.06%, 49.17%, 9.72% for F5, F4, F3, F2, and F1, respectively. The result also showed that the F4 sample was the most preferred sample.

P-μ-T cubic equation of viscosity for hydrocarbons

Viscosity model is important for the simulation of flow and recovery behaviour of different hydrocarbon systems. Various semi-theoretical models such as Friction-Theory and cubic Equation of State-based models have been found satisfactory for lighter crudes. However, for heavier hydrocarbon systems e.g. heavy oils, bitumens, these models are not reliable; one possible reason is that they are not reliable for heavier components. The objective of this research is to develop a viscosity model sensitive to molar mass and density of components and a mixture of hydrocarbons.In this work, a Cubic Equation of Viscosity model where P-ρ-T form of cubic equation (Abbott, 1973) is converted into P-μ-T form of cubic equation, is developed with desired sensitivity to density and molar mass. The model requires three parameters, which are optimized by viscosity data matching. Separate sets of parameters are developed for hydrocarbon groups such as paraffins, naphthenes, and aromatics. Viscosity estimation for mixture requires mixing of the parameters and not the viscosity values of individual components.The carbon number of heaviest component used in the model is 64. The P-μ-T viscosity model has AARD of 2.91%, 3.06% and 5.68% for paraffins, naphthenes, and aromatics respectively in comparison of 33.95%, 19.6%, and 48.9% from T-μ-P (Guo et al., 2001) model. Friction Theory (Quinones-Cisneros et al., 2000) based model results in 26.38% AARD for paraffins. For 19 paraffinic mixtures, AARD from P-μ-T is 5.56% in comparison to 29% from T-μ-P (Guo et al., 2001) model and 316% from Friction Theory (Quinones-cisneros et al., 2000) model.

Thermal storage performance of paraffin and fatty acid mixtures used in walls and floors

The phase change temperature and latent heat of binary paraffin and fatty acid mixtures were measured using a differential scanning calorimeter. 18 types of samples were found to be suitable for passive walls with phase change temperature ranging from 20 °C to 30 °C. In addition, fifteen types of samples were found suitable for active heating floors or walls with a phase change temperature of 30 °C to 40 °C. Five thousand thermal cycling tests were performed on six representative samples. Based on the experimental results, the average change rates of the phase change temperature of paraffin and fatty acid mixtures were found to be less than 5% and 1%, respectively. These phase change materials exhibited good thermal stability, and the thermal stability of fatty acids was better than that of paraffin mixtures. The appropriate proportions of phase change materials for passive phase change walls and active phase change floors or wall was obtained.

One-pot solvothermal synthesis of Fe/Fe3O4 composites with broadband microwave absorption

In the present work, we have developed a simple and low-cost solvothermal method for the one-pot construction of the Fe/Fe3O4 composites with the Fe3O4 nanoparticles depositing on the surface of Fe polyhedrons. The Fe3O4 content in the Fe/Fe3O4 composites can be easily improved by the decrease of volume ratio of ethanol (95 vol%)/distilled water (Vethanol/Vwater). The electromagnetic parameters of the Fe/Fe3O4 composites (70 wt%)-paraffin mixtures are deeply depended upon the Fe3O4 content. The complex permittivity is gradually decreased and the complex permeability maintain the modest value with the increase of the Fe3O4 content. When the Fe3O4 content is 56 wt%, the minimum reflection loss (RL) value can reach −33 dB at a matching thickness of 1.5 mm. The optimal RL is −24.6 dB at 2 mm with the absorption bandwidth of 5 GHz and the integrated bandwidth with RL below −10 dB is 14.4 GHz in the frequency range of 3.6–18 GHz with a changeable thickness of 1.4–5 mm. Due to the double-loss characteristics of the Fe3O4 nanoparticles, the wide-frequency microwave absorption properties of the Fe/Fe3O4 composites at high frequency can be attributed to dipole polarization relaxation loss of the Fe3O4 nanoparticles, interfacial polarization relaxation loss between Fe and Fe3O4 and preferable impedance matching. This result indicates that the Fe/Fe3O4 composites could be a candidate for microwave absorption field.

Thermal behaviour of wallboard incorporating a binary mixture as a phase change material

In this study, a physical model is developed to examine the thermal behavior of a mortar wallboard enclosing a phase change material (PCM). A binary mixture of paraffin (hexadecane-octadecane) is selected as a PCM. The porous medium approach is adopted to investigate the conduction heat transfer through the wallboard. The enthalpy porosity formulation is employed to describe the phase transition inside the PCM. The physical model was successfully verified by comparing its numerical results with the data from the literature. Numerical simulations were performed to determine the thermal response of the wallboard under periodical outside temperature. The effect of the PCM mass, the initial concentration of the binary mixture, the inside and outside heat transfer coefficients and the outside temperature amplitude on the thermal behavior is explored in detail. The time lag (φ) and thermal decrement factor (f) as indicators of the thermal inertia of the wallboard are also discussed and presented. The obtained results show that the use of a pure PCM increases the time delay of the thermal response, while binary mixtures allow reducing the amplitude. In other hand, the thermal behavior of the PCM-Mortar wallboard is optimized as well as the outside convective heat transfer coefficient is lower and the inside convective coefficient is higher.