Paraffin Content Research Articles

ДРУГИЙ СТАНДАРТ УКРАЇНИ НА БІТУМИ НАФТОВІ ДОРОЖНІ В’ЯЗКІ: ЗМІСТ ТА ПЕРСПЕКТИВИ

The first Ukrainian standard ДСТУ 4044 “Viscous petroleum road bitumens. Technical conditions” was implemented in 2002. According to its content and list of indicators, it met the level of the oil refining industry of Ukraine and the state of the road industry. In addition to conventional indicators, it included additional indicators of adhesion and mass content of paraffins. The indicator for paraffin remained unregulated, because there was neither acceptable method nor necessary equipment, and in generally an intention of manufacturers and users to apply it. The standard referred to in the article differs from the previous one by the principle of assigning indicators and their list. This is largely due to Ukraine’s accession to the European Free Trade Association and the deepening of scientific knowledge on predicting the behavior of bitumen under different conditions and their impact on the properties of asphalt concrete. Accordingly, the limits of normalization of bitumen grades on the depth of needle penetration were changed, which led to an increase in amount of grades from 4 to 5. Using the dependence of the penetration index on the softening point temperature, its new normative values are ordered. The Fraas breaking temperature provided by the standard is slightly lower than that normalized EN 12591 which is due the climatic conditions of Ukraine. The rate of adhesion of bitumen to the surface is normalized, which quantitatively characterizes the adhesion of bitumen to the mineral substrate, the least favorable for interaction. It is proposed to determine the indicators of technological aging by the RTFOT method. The standard contains additional indicators to be determined according to the harmonized European standards ДСТУ EN 12607-1 and ДСТУ EN 13302 (methods for determining the dynamic viscosity). Additional standards include equal viscous heating temperatures of bitumen in the production of asphalt mixtures and their compaction. The first is the temperature, which corresponds to a bitumen viscosity of 0.5 Pas, the second is 10 Pas. Elongation at a temperature of 0 ºC is included in the standard as a certain analogue of the breaking temperature. Based on the fact that at this time the next European standard is in the final stage before approval, the values of additional indicators can be included into this standard after adjusting their values with European ones based on the characteristics of bitumen used in Ukraine. Keywords: bitumen, depth of needle penetration, softening point temperature, adhesion, ductility, cohesion, heating.

Phytoremediation potential of sorghum bicolor for soil decontamination from oil hydrocarbons and heavy metals

The results of vegetation experiments carried out over 12 of years in order to assess the application of Sorghum bicolor (L.) Moench) for soil clean up from oil hydrocarbons and heavy metals in the Saratov Region are given. It was found that the cultivation of sorghum in contaminated soils under controlled conditions for 2 to 4 months led to the elimination of hydrocarbon pollutants by 21-98%. The decrease in the concentration of oil and oil sludge occurred primarily due to the reduction of the content of paraffins and naphthenes fractions. The degradation of diesel fuel and of phenanthrene as an individual polycyclic aromatic hydrocarbon was most successful. The role of the plant in the manifestation of the rhizosphere effect and of the pollutant detoxification was suggested to be based on the coupled plant-microbial metabolism of pollutants in the rhizosphere. The high extracting activity of sorghum towards heavy metals such as cadmium and nickel was revealed. Sorghum plant can accumulate up to 1003 mg of metals per kg of dry biomass. It was shown that cadmium predominantly accumulated in the sorghum roots. High concentrations of nickel accumulated in the plant shoots. Special attention is paid to phytoremediation of mixed pollution of soil with hydrocarbons and metals. A significant mutual influence of petroleum hydrocarbons and heavy metals on their elimination from soil has been established. The presence of organic pollutants reduces cadmium and nickel extraction capacity of sorghum. In contrast, cadmium increased the degradation of oil sludge. The data obtained emphasize the need for more detailed studies of the mutual influence of the components of mixed pollution in order to understand and predict the cleaning up processes in the environment. In general, taking into account the economic and biological characteristics of sorghum crops, it was concluded that the application of sorghum is promising for phytoremediation of contaminated soil in the Saratov Region.

Исследование причин образования асфальтосмолопарафиновых отложений товарной нефти в условиях эксплуатации магистральных нефтепроводов

The results of investigations of the main causes and the most significant factors of intensification of paraffin deposition in main oil pipelines are presented. A comprehensive analysis of the composition and properties of commercial oils and their sediments was carried out, according to which phase diagrams of equilibrium of oil dispersed systems were obtained using the example of commercial oils from Bashkir fields. Based on the phase diagrams, a curve of wax oil saturation was constructed, the analysis of which confirms that the existing thermobaric conditions during the operation of main oil pipelines do not allow transporting oil without the risk of waxing. It was noted a special influence of the value of the temperature gradient in the near-wall zone and the imbalance of the ratio of high-molecular oil components in commercial batches formed in the process of joint pumping on the intensity of waxing of sections of oil pipelines complicated by deposits, which was confirmed by statistical data on the frequency of pigging. The regularities obtained in this way are proposed to be used as an express method for predicting complications associated with intensive waxing of main oil pipelines. In order to quickly assess the risks of waxing of sections of main oil pipelines, an indicator is introduced that characterizes the ratio of the content of solid paraffins to the total content of resins and asphaltenes of oil, called the criterion of instability of a commercial oil batch.

Bitumen froth treatment in the transition region between paraffinic and naphthenic process conditions

Bitumen froth treatment is an important process step of the bitumen recovery from oil sands by surface mining. In bitumen froth treatment, water and mineral solids are separated from the target organic bitumen product by using hydrocarbon solvents. Residual water and mineral solids in the bitumen product are detrimental to pipeline transport and downstream processes. Depending on the solvent composition, the commercial naphthenic and paraffinic bitumen froth treatment processes proceed via the oil-water separation mechanisms of coalescence and agglomeration, respectively. This study presents an experimental proof-of-concept for the existence of a transition region at ambient conditions and solvent-to-bitumen ratio of 1.6, where the advantages of the two commercial froth treatment processes may be combined and the drawbacks essentially eliminated. The bitumen product obtained in the transition region is virtually free from residual water and solids (<0.1 wt%), using gravity settling alone, as in the paraffinic process, and the asphaltenes are retained, as in the naphthenic process. The transition region range is determined at 2.2–4.5(±0.2) wt% aromatic or 70–80(±10) wt% paraffinic content of the solvent. Bitumen froth treatment in the transition region recovers a sufficient amount of oil product with gravity settling alone. These findings suggest that conducting bitumen froth treatment in the transition region could increase both hydrocarbon recovery and product quality. This approach may be valuable not only for bitumen froth treatment but also for other oil-water separation processes, such as in situ bitumen recovery.

Efektywność środków chemicznych stosowanych w przesyle ropy naftowej z odwiertu do instalacji procesowych

Chemicals are added to crude oil to ensure that it flows from the well to the processing plant. Depending on the composition of the reservoir fluids being extracted (crude oil, reservoir water, natural gas), paraffin may be separated from the crude oil, hydrates may be formed from reservoir water and natural gas, and the combination of reservoir water and crude oil may form an emulsion. Those situations should be avoided to ensure continuous flow from the wellbore to the processing plant. To this end, chemicals, paraffin inhibitors, hydrate inhibitors, and demulsifiers are used. Based on the literature on the subject and on the author’s own experience from observing technological processes, research methods were proposed to assess the effectiveness of chemicals used to ensure the continuity of crude oil flow. The crude oil selected for the tests was characterised by a high content of paraffins, asphaltenes, chloride ions, and water. To determine the onset of paraffin precipitation, tests were conducted based on a change in viscosity and a coupon method – determining the weight gain on a coupon to check the effectiveness of a paraffin inhibitor. The rate of emulsion separation was evaluated in separating funnels. The water released from crude oil often leaches the salt contained within it. Various demulsifiers were used to investigate the separation of emulsions and the purification of oil from salts; silicone demulsifiers in particular were considered. To determine the change in the amount of salt in crude oil, a conductometric measurement was performed. The amount of demulsifier used for phase separation was determined by changing the surface tension. The proposed solution for the use of chemicals to transport and purify crude oil yields tangible economic benefits. The article summarises the research procedures and presents the results for selected crude oil and chemicals.

Study of the composition and properties of crude oil mined at the Ichyodinskoye field

This study was aimed at investigating the chemical composition and commercial properties of crude oil mined at the Ichyodinskoye field. A graph of atmospheric distillation was constructed. The content of commercial fractions was determined from the curve of true boiling temperatures. The obtained data were analysed according to the hydrocarbon composition of the gasoline fraction, which was found to comprise alkane, cycloalkane and aromatic compounds in the amount of 53.12%, 27.21% and 18.45%, respectively. In terms of sulphur, the oil mined at the Ichyodinskoye field is considered to be low-sulphur, thus belonging to the1st class. A distinctive feature of this oil consists in its inability to form stable emulsions due to a low content of solid paraffins in its composition. In the study, artificial emulsions of the oil and deposit water with a watercut value of 30% were obtained. The developed emulsions were investigated by analysing the process of gravitational settling for 120 min at a temperature of 50 °C, as well as using a LUMiFuge device. It was found that the oil mined at the Ichyodinskoye field is low-sulphur and light, containing a high content of light distillates. It is known that low-sulphur oils are safer for field equipment in terms of corrosion, thereby decreasing costs of supplying oil to consumers. Such oils are a high-quality and promising raw material for the production of oil products.

Tuning interaction of surface-adsorbed species over Fe/K-Al2O3 modified with transition metals (Cu, Mn, V, Zn or Co) on light olefins production from CO2 hydrogenation

The presence of transition metals (Cu, Co, Zn, Mn or V) in Fe/K-Al2O3, modifying the adsorption-desorption properties of CO2 and H2 with the catalyst surface remarkably influences the catalytic performance for CO2 hydrogenation to light olefins. The addition of either Cu or Zn to Fe/K-Al2O3 significantly increases the number of weakly adsorbed H atom, yielding the high CO2 conversion and shifting the product distribution towards longer chain hydrocarbon with a higher content of paraffins. The addition of Co to Fe/K-Al2O3 also enhances the CO2 conversion but it provides the short chain hydrocarbon (C1-C4) and thus achieving the highest light olefins yield of 16.2%. The presence of either Mn or V inhibits the CO hydrogenation to hydrocarbon, leading to the low CO2 conversion. The Mn promoter reduces the number of weakly adsorbed H atom, lowering the hydrogenation ability of the catalyst, resulting in the highest olefin to paraffin ratio of 7.4.

ASA/SEBS/paraffin composites as phase change material for potential cooling and heating applications in building

Phase change material (PCM) is able to melt and crystalize with a high heat of phase change at constant temperature, which provides new and green cooling and heating strategies for buildings. In this work, PCMs for buildings composed of acrylonitrile‐styrene‐acrylate copolymer (ASA), polystyrene‐b‐poly(ethylene/butylene)‐b‐polystyrene triblock copolymer (SEBS) and paraffin were fabricated by melt blending. The results of the accelerated leakage test indicated an excellent ability of PCMs to keep paraffin from leakage. Thermal properties suggested that the phase change enthalpy of PCMs increased with the increasing content of paraffin and their phase change temperature was close to the comfortable sensible temperature of human body, which made it quite suitable for building cooling and heating. Besides, PCMs presented excellent stability and reusability after several thermal cycling tests. The temperature test conducted with self‐designed cylindrical devices gave a more sufficient and direct demonstration of the cooling and heating effect. Remarkably, excellent cooling and heating performance (both as high as 15°C) of the composites could be obtained with the addition of paraffin. And the time span of the cooling and heating process was as long as 5 and 7.5 hours, respectively. Owing to its excellent cooling and heating capabilities, the ASA/SEBS/paraffin composites are of great potential to be applied in building temperature control.

Application of a sequential multi-solid-liquid equilibrium approach using PC-SAFT for accurate estimation of wax formation

Several existing thermodynamic models for Wax precipitation use cubic EOS and average properties for petroleum fractions. To improve predictions, this work introduces a thermodynamic model using a multi-solid framework in a sequential equilibrium calculation procedure. The PC-SAFT EOS is used to predict liquid phase properties. Binary interaction coefficients and difference of heat capacities between solid and liquid are adjusted to minimize the deviations caused by the employment of averaged relations for properties of hydrocarbon cuts. Three groups of oil samples are chosen for verification. First, the Wax precipitation data of three synthetic mixtures from Pauly et al. [1] are estimated, and the modeling results are compared to the predicted results of Dalirsefat and Feyzi [2] and Schou Pedersen et al. [3]. Also, two crude oil samples with Paraffin, Naphthene, and Aromatic (PNA) content from Pan et al. [4] are used for evaluation. Finally, the suggested model is used to calculate weight percent of precipitated Wax and Wax appearance temperature (WAT) of six crude oil samples from North Sea [3]. The calculated predictions of the suggested model are compared to the works of Schou Pedersen et al. [3], Lira‐Galeana et al. [5], and Bagherinia et al. [6]. The deviations for WATs and precipitation amounts from experimental data are lower compared to previous studies. The average absolute deviation for precipitated Wax weight of the North Sea samples is 0.19 in comparison to 0.61, 0.33, and 0.4 of Schou Pedersen et al. [3], Lira‐Galeana et al. [5], and Bagherinia et al. [6], respectively.

Study on the Influence of Processing Oil on the Physical Mechanical Properties and Adhesion of Ethylene Propylene Diene Monomer (EPDM) Rubbers to Polyester Fabrics

In this paper, the influence of paraffinic oil on the physical mechanical and thermal properties of three EPDM rubbers types Buna EP T.6465, Keltan 5260Q and Keltan 6160 D have been investigated. The results showed that the tensile strength and the elongation at break of Keltan 5260Q and Keltan 6160 D with 10 phr paraffinic oil represent the improvement of 57.8% to 57.6% and 71% to 81% respectively, compared to EPDM rubbers without paraffinic oil. The mean peel force of EPDM keltan 6260D with 10 phr paraffinic oil loaded is about 36% and 32.5% higher than that of keltan 5260Q and EP.T 6465 respectively. Beside that at the suitable paraffinic oil contents, the thermal resistance of Keltan 5260 Q and 6160D seems to be a little higher than that of without processing oil and these EPDM rubbers are suitable for application to high thermal resistance rubber products.

Preparation and Characterization of Paraffin@CLPS/MS Phase Change Microcapsules for Thermal Energy Storage

AbstractIn this study, a series of encapsulated micro phase change material (EMPCM) based on industrial paraffin and inorganic‐organic hybrid shell was reported. The microcapsules (28#P@CLPS/MS) were synthesized with 28#paraffin (28#P) as phase change material (PCM), crosslinked polystyrene (CLPS) as flexible organic shell and modified nano SiO2(MS) as rigid inorganic shell, via a Pickering emulsion polymerization method. MS reduces the interfacial tension of water and plays a good emulsification effect. Secondly, after polymerization, the mechanical stability of the microcapsule shell can be enhanced, and the thermal reliability of the phase change microcapsules can be improved. The morphology, thermal energy storage capacity, and structure of microcapsules were characterized and analyzed. Besides, the grafting ratio of nano SiO2on the heat storage properties of microcapsules was investigated. When the graft ratio of nano‐SiO2was 4.2 %, the prepared microcapsules with highst paraffin content (54.37 %) and encapsulation efficiency (95.15 %). The synthesized microcapsules with regular spherical shape and size range of 1–5 μm, latent heat capacity (Tm28.20 °C, 86.35 J/g) and good thermal stability. Besides, the chemical composition of the microcapsules did not change after 500 cycles, and the latent heat did not decrease. Our research shows that Pickering emulsion polymerization is a convenient, economical and green method for the preparation of highly stable energy storage microcapsules.

Preparation of Expanded Graphite and Fly Ash Base High Temperature Compound Phase Transition Heat Absorption Material and Its Application in Building Temperature Regulation

In this study, the product substance was pretreated with coal excrement as a raw product substance. Taking expanded graphite and paraffin as phase change product substances, expanded graphite and paraffin or coal excrement base high temperature compound phase transition thermal storage product substance were prepared by mixed sintering method. Firstly, the sintering mechanism of the composite should be deduced. In addition, XRD, TG-DSC and other analytical techniques were used to characterize the morphology and physical character of the product substances. In order to test the temperature regulation ability of the product substance, the composite product substance was fused with cement. The cement block added with composite product substance was taken as the research object, verify the performance of compound phase transition product substance on temperature regulation. In the experimental procedure, when phase change product substances' the proportion was less than 60%, the high temperature compound phase transition thermal storage product substances prepared were well-formed and had good crystallography, and the green body' various tissues were densely distributed. When the paraffin content was above 35 wt%, the external density, compressive strength, and cement blocks' thermal conductivity added with composite product substances increased significantly compared with ordinary expanded perlite cement blocks, which was suitable for building product substances' requirements. When the paraffin content reached 38 wt%, a temperature difference of 19.2 °C to 26.1 °C appeared in the composite product substance' corresponding cube space, indicating that room temperature can be adjusted by adding a certain phase change product substance.

In situ formed carboxylic acids effect on light hydrocarbons oxidation in a carbonate reservoir

Enhancing heavy oil recovery is attracting a considerable interest due to the depletion of conventional oil resources. In fact, thermal enhanced oil recovery methods are presenting a potential impact on improving heavy oil recovery especially for terrigenous reservoirs, where they are able to increase oil mobility due to heating (steam and thermal exposure) or due to its in-situ conversion to light fractions during ignition of the reservoir. At the same time, it is worthy to note that steam-thermal methods are accompanied by a significant heat loss when injecting steam into great depths heat. Moreover, oil deposits in heterogeneous low-permeability reservoirs (for example, carbonate) are among the potential unconventional oil resources. Along with geological heterogeneity, low porosity and permeability, fracturing, these reservoirs contain, in most cases, heavy oils with a high content of resins, asphaltenes and hard paraffins, characterized by a non-Newtonian fluid property. All this taken together makes the extraction of oil from such reservoirs a hard task to implement.

KAOLINITE MODIFIED BY ALUMINUM IN THE CRACKING OF VACUUM GASOIL AND IT’S MIXTURE WITH FUEL OIL

The data of the cracking of vacuum gas oil (VG) and a mixture of VG with fuel oil (M-100) on HLaY zeolite catalyst based on acid-activated kaolinite of the Pavlodar deposit modified by aluminum are presented. The synthesis of the kaolinite matrix and the HLaY zeolite catalyst with its use, the physicochemical and acid characteristics of the catalyst and its constituent components, and the fractional and hydrocarbon compositions of vacuum gas oil are described. High mesoporosity of the H-form of the used kaolinite (86.2%), modified by aluminum of the H-form (84.1) and the HLaY catalyst (80.1%), which provide the activity of the sample in cracking of the mixture with a yield of 32.6% gasoline and 25.9% light gas oil (LG) at 4500С and in cracking of VG a yield of 38.2% gasoline and 29.4% LG at 5000С. The gasolines of cracking of LG contain an increased content of iso paraffins (up to 20.2%) and a low content of aromatic hydrocarbons (24.1%), which makes the catalyst attractive for cracking a mixture of VG with fuel oil. Key words: catalytic cracking, kaolinite, vacuum gas oil, fuel oil, zeolite, modification.

Microemulsion based synthesis of promoted Fe–Co/MgO nanocatalyst: Influence of calcination atmosphere on the physicochemical properties, activity and light olefins selectivity for hydrogenation of carbon monoxide

Nanostructured promoted Fe–Co/MgO catalysts were fabricated by microemulsion technique and used for Fischer-Tropsch synthesis, for the first time. Regarding the deficiency of the systematic investigation correlated to the calcination atmosphere on FT catalytic performance, in this study, the effect of different calcination atmospheres on the catalytic activity, product selectivity, and physicochemical properties of promoted Fe–Co/MgO catalyst was investigated. To obtain uniform particle size distribution, the microemulsion technique was used. The prepared nanocatalysts were characterized by XRD, TGA, BET, ICP-OES, FESEM, TEM, FTIR, XPS, and H2-TPR. The higher activity, methane selectivity, and lower C3+ selectivity were obtained for the air-calcined catalyst. Calcination under Ar atmosphere resulted in lower activity, methane selectivity, but higher C3+ selectivity (with high paraffin contents). Characterizations indicated that these performances are related to the metal particle size and reducibility. The air-calcined catalyst with smaller particle size and higher reducibility rather than Ar-calcined one, demonstrated higher activity, oxidized more quickly in the preliminary operation period of Fischer-Tropsch synthesis, and encouraged the formation of CH4 and CO2.

Addition of two kerosene-based fuels to diesel–biodiesel fuel: Effect on combustion, performance and emissions characteristics of CI engine

This work investigates the effect of adding two kerosene-based fuels namely jet fuel (J100) and paraffinic solvent (P100) to diesel and diesel–biodiesel blends on performance, combustion characteristics and emissions of high-compression ratio (21.5) compression ignition (CI) engine. Engine experiments were conducted at a constant speed of 2000 rpm over the entire load span. Experiments were performed using a single cylinder, air-cooled, 4-stroke, direct injection CI engine. Three volume-based blending ratios including 5%, 10% and 15% of each additive were separately-blended with neat diesel and with B30 (70% diesel, 30% biodiesel). The two additives have a same number of carbon atoms C10−C13. FT-IR and GC–MS measurements showed that J100 has higher aromatic/less paraffinic contents than P100. Engine experiments revealed that for binary blends, adding 15% of J100 and P100 to diesel achieved maximum average reduction of 8.4% and 5.6% in brake specific fuel consumption (bsfc), respectively. Ternary blends kept running on bsfc close to this of diesel. For binary blends, stable performance of the engine was attained only with up to 10% addition of P100 or J100. For ternary blends, stable performance was achieved up to 10% and 15% of P100 and J100, respectively. Maximum reduction in NOx emissions of 38.7% was achieved for D95-P5. While B30-J15 achieved maximum reduction in CO emission of 50.3%. Using optimization maps, 10% and 15% of J100 were found as the optimum blending ratios for binary and ternary blends, respectively. These ratios achieve stable and economic performance with low NOx and CO emissions.

Paraffin/chitosan composite phase change materials fabricated by piercing-solidifying method for thermal energy storage

To study the effects of emulsifier content on the structure and thermal properties of encapsulated phase change materials (PCMs), four kinds of paraffin/chitosan (CS) macroencapsulated PCMs with different emulsifier contents were fabricated via the piercing–solidifying method. The effects of emulsifier content on macro-profile, micromorphology, thermal energy storage properties, and thermal durability of the as-prepared composite, as well as the structure of the optimal capsules, were investigated. The results show that the non-spherical degree, average diameter, and compressive strength decreased first and then increased with increase in emulsifier content, resulting in thermal energy storage capacity’s increase at first and then its decrease. The optimal macro-capsules, fabricated at the critical micelle concentration of the emulsifier, present a regular spherical surface and microencapsulated paraffin wax inside. The paraffin content is as high as 85%, with a phase change latent heat of 112.6 J g−1 for melting and 118.7 J g−1 for solidification. The melting enthalpy and weight loss ratio of the optimal paraffin/chitosan composite after 600 heating/cooling cycles only changed to 0.71% and 1.17%, respectively. These results not only suggest that the piercing–solidifying method can be employed to fabricate macro-capsules with high heat storage performance and excellent thermal stability but also reveal that paraffin/CS can be used in thermal management at low temperature.

Scrap tires pyrolysis oil as a co-feeding stream on the catalytic cracking of vacuum gasoil under fluid catalytic cracking conditions

The co-feeding of scrap tires pyrolysis oil (STPO) on the catalytic cracking of vacuum gasoil (VGO) has been investigated with the aim of exploring the capacity of the refinery fluid catalytic cracking (FCC) unit to upgrade discarded tires at large-scale. The runs have been carried out in a CREC (Chemical Reactor Engineering Centre) riser simulator reactor that mimics the behavior of the industrial unit at the following conditions: 500–560 °C; catalyst/oil ratio, 3–7 gcat goil−1; contact time, 6 s. Obtained results with the blend of 20 wt% STPO in VGO have been compared with those obtained in the cracking of the pure streams, i.e., STPO and VGO, to get a proper idea of the synergetic effects that could be involved in the co-feeding. This way, when the STPO is co-fed with the VGO the production of naphtha (C5–C12) and light cycle oil (C13–C20) lumps are maximized, as the over-cracking reactions that convert them into gaseous products (C1–C4) are mitigated. Consequently, the co-feeding promotes the production of high-interest hydrocarbons for refineries. Additionally, the naphtha obtained in the cracking of the blend shows a lower content of paraffins and naphthenes than that obtained with the VGO, and higher of olefins and aromatics.

Emerging paraffin/carbon-coated nanoscroll composite phase change material for thermal energy storage

Thermal energy storage using phase change materials is considered as a significant strategy for relieving the energy crisis. Herein an emerging paraffin-based composite form-stable phase change material (FSPCM) was fabricated using carbon-coated nanoscroll (CAN) as supporting material prepared via in-situ carbonizing the delaminated kaolinite (Kaol). The effect of carbonization temperature on the thermal performance of composite FSPCM was investigated. The samples were characterized using XRD, FTIR, DSC, XPS, SEM, TEM, TG, and nitrogen adsorption-desorption isotherms. The results indicated that the pore properties of the exfoliated and carbonized Kaol significantly increased, which was beneficial to the high loading and leakage-proof. The optimum paraffin content of CAN composite FSPCMs without leakage is 60.63%, 63.14%, and 59.99% for calcination at 600 °C, 700 °C, and 800 °C, respectively. Paraffin/CAN composite FSPCMs have the phase temperatures of 51–58 °C and high latent heat of 123–142 J/g. Compared with pure paraffin, the thermal conductivities of paraffin/CAN composite FSPCMs were increased by 1.98, 1.92, and 2.01 times for calcination at 600 °C, 700 °C, and 800 °C, respectively. The composite FSPCMs exhibit excellent thermal and chemical stability after 1000 thermal cycles, indicating that paraffin/CAN composite FSPCMs have excellent potential in the solar energy storage system.

A high heat storage capacity form-stable composite phase change material with enhanced flame retardancy

A high heat storage capacity form-stable composite phase change material (CPCM) with enhanced flame retardancy that integrated modified glass fibers with form-stable PCM was proposed. The modified glass fibers were wrapped by a composite flame retardant coating. The thermal and flame retardant properties of the CPCM were measured and compared to other CPCM samples. The results of vertical burning test indicated that the glass fibers improved the mechanical properties of the CPCM and prevented it from fracturing during the burning process. The modified glass fibers could further improve the flame retardancy of CPCM, and V-0 burning rating was achieved while the content of paraffin was maintained at 70 wt%, which means the proportion of flame retardants could be reduced. TGA results showed that the modified glass fibers could enhance the thermal stability and retard the degradation process of the CPCM, and the char residue was increased to 15.3%. Thermal cycling results indicated that the CPCM has good thermal reliability. The results of cone calorimeter test indicated that the peak heat release rate (PHRR) of flame retardant form-stable CPCM dropped by 58.8%, and the combustion rate could be greatly slowed down due to the protection of carbon layers formed by modified glass fibers. In addition, the thermal conductivity of CPCMs were greatly enhanced and the CPCM has good thermal reliability.