Paraffinic Components Research Articles

Aluminum powder impact on the efficiency of diesel fuel dewaxing by centrifugation

Relevance. The improvement of the low-temperature properties of diesel fuels is achieved using various methods of dewaxing and isomerization, leading to almost complete loss of n-alkanes and, accordingly, to deterioration in the detonation properties of fuels. Partial dewaxing of diesel fuels is of interest. It allows the preservation of most of the n-alkanes. Objects. Diesel fuel of a weighted fractional composition, the improvement of low-temperature properties of which is carried out by means of its partial dewaxing by centrifugation with the addition of aluminum powder to the fuel. Methods. Initial diesel fuel dewaxing was carried out on a refrigerated centrifuge SL/8R Centrifuge, which provides a rotor rotation speed of up to 9500 rpm in the temperature range from 40 to minus 10°C. At low temperatures, relatively high-melting paraffin components were released as a precipitate in the rotor tubes. The efficiency of the initial diesel fuel dewaxing was evaluated by the dewaxed diesel fuel yield and by its quality indicators – turbidity temperature, refractive index, filterability limit temperature and solidification temperature. The distribution of n-alkanes in the dewaxing products relative to the starting fuel was determined by gas-liquid chromatography. Aim. To increase the efficiency of the diesel fuel dewaxing by centrifugation with the addition of aluminum powder to the raw material as a paraffin weighting agent. Results and conclusions. The authors have determined the optimal parameters of diesel dewaxing to ensure the production of summer diesel fuel of the "C" brand corresponding to EN 590. The maximum yield of dewaxed diesel fuel at optimal process parameters reaches 78.6 wt %. Dewaxed diesel fuel has a turbidity temperature of minus 5°C, its maximum filterability temperature is minus 6°C and the solidification temperature is minus 15°C.

Modelling and Simulation Studies on the Characteristic Behaviour of Macroalgae Derived Bio-Oil

Abstract With the expanding need for renewable and sustainable energy resources, the demand for biomass derived bio-oil particularly microalgae or macroalgae based bio-oil is growing. In this regard, understanding the characteristics of bio-oil as a function of several influencing operational parameters is essential. In this study modelling and simulation technique based on Aspen HYSYS was applied to investigate the characteristics of macroalgae Ulva prolifera derived bio-oil from Hydrothermal Liquefaction (HTL) process as a function of the influencing parameters like temperature, kinematic viscosity, and weight percent of the bio-oil assay, cut yield behaviour, and standard liquid density. Modelling and simulation help to optimise the process parameters and design the process layout for large-scale production. According to the simulation results the cut yield of off gases, light naphtha, heavy naphtha, light distillate, heavy distillate, gas oil and residues are shown at specific final boiling point (FBP) temperatures of 70 °C, 70 °C - 110 °C, 110 °C - 221.1 °C, 221.1 °C - 304.4 °C, 304.4 °C - 371.1 °C, 371.1 °C - 537.8 °C and 537.7 °C respectively. Whereas, above a temperature of 300 °C, the weight percentage of aromatic components increased steadily. The increase in percentage composition of the aromatic components is due to the reduction of the paraffinic components. The density of the liquid bio-oil was steadily increasing until a temperature of 200 °C.

Reaction mechanism study of catalytic conversion of light straight-run naphtha to light olefins over micro-spherical HZSM-5 zeolite catalyst

Catalytic conversion of naphtha has attracted attention as an alternative method to the conventional thermal cracking to produce light olefins in an environment-friendly and energy-efficient way. In this work, a reaction mechanism study of light straight run naphtha cracking over micro-spherical catalyst containing HZSM-5 was systematically investigated using single hydrocarbon feeds, and the straight run naphtha itself. The identified reaction pathways from the single feeds along with the naphtha experimental data have been utilized to investigate reaction pathways of the naphtha conversion reactions. The experimental tests were carried out in the temperature ranges of 450–650 ℃ and space-times of 0.3–1.5 min using a fixed bed micro-reactor in isothermal and isobaric conditions. The product distribution for the naphtha feed shows that light paraffins and light olefins are the primary products, which are products of monomolecular protolytic cracking of the paraffin components of the naphtha feed. The olefin interconversion reactions illustrated that oligomerization and cracking by β-scission dominate the secondary reactions of naphtha catalytic cracking conversions. The experiments conducted on cyclohexane, cyclohexene and n-hexane single feeds revealed that BTX formation proceeds through the formation of C6-C8 naphthenes, and C6-C8 cyclo-olefinic intermediates. Low temperatures and space times promote the selectivity to propylene while the selectivity of ethylene increases with temperature. The degree of thermal cracking (DTC) illustrated that thermal cracking is considerable only for temperatures of higher than 550 ℃.

Ti3C2Tx MXene and cellulose-based aerogel phase change composite decorated laminated fabric with excellent electro/solar-thermal conversion and high latent heat

Wearable heaters have attracted growing attention for maintaining a relatively constant temperature of the human body in cold environments with near zero energy consumption. Herein, we developed a multifunctional laminated fabric with fascinating electro/solar-thermal conversion, thermal energy storage and thermal insulation properties. With cotton fabric as the substrate, MXene/polydimethylsiloxane (PDMS) conductive network was decorated on the upper layer, and carbon nanotube (CNT)/cellulose nanofiber (CNF)/paraffin (PA) aerogel phase change composites were assembled on the bottom layer. Attributed to the strong conductivity and light absorption of MXene and the light/thermal response of CNT and PA components, this wearable laminated fabric broke the limitation of intermittent solar photothermal heating, and integrated multiple heating modes to precisely heat the human body. Meanwhile, the low thermal conductivity of aerogel retarded heat loss. The laminated fabric can help people better adapt to a variety of complex and changeable environments such as cold winter, rainy days and nights. This study provides a promising and energy-efficient avenue for the development of all-day personal thermal management fabrics.

Hydrophilic candle wastes microcapsules as a thermal energy storage material for all-day steam and electricity cogeneration

On-site reclamation of freshwater from seawater is urgently desired to combat freshwater scarcity, in which solar-driven interfacial evaporation has been realized as a promising strategy. However, solar desalination has been facing the negative influence of intermittent solar radiation alternating day and night; thus, incorporating a material recommended as thermal energy storage material into the photoabsorber is a profitable strategy to supply the heat for 24-h steam generation. Herein, graphene oxide (GO) was incorporated with the candle waste to store the thermal energy and encapsulated into the SiO2 shell to prevent the leakage of the paraffine wax and enhance the membrane hydrophilicity. A collaborative device including the evaporator and a commercial thermoelectric (TE) module was designed for steam-electricity cogeneration which exhibits a simultaneous evaporation rate of 1.09 kg m−2 h−1 and power density of 6.8 W m−2 under one sun irradiation. Besides, the paraffin component can store thermal energy, enabling the device to maintain a certain steam and electricity cogeneration of 0.35 kg m−2 h−1 and 2.8 W m−2 after light-off. This work may provide a cost-effective strategy for the fabrication of potential photoabsorbers from environmental wastes for all-day water evaporation and power cogeneration device to mitigate freshwater and electricity shortages.

A pilot project of TESS equipped with two models of encapsulation for nano-enhanced organic PCMs

ABSTRACT The unique thermal energy storage system (TESS) as an auxiliary system of solar water heater has a critical part to demonstration in preserving and efficiently utilizing energy, resolving demand-supply mismatches, and boosting the efficiency of energy systems. In this research, a suitable Nano enhanced-Composite Phase Change Material (NCPCM) was prepared to utilize in two model of metal cylinders. First of all, an experimental test for determination of melting point has been investigated by temperature variation test (TVT) method for NCPCM based on paraffin component. Then, two nanomaterial types (TiO2 and CuO) mixed at 50%/50% with two concentrations (0.6% and 0.12%) were dispersed with slack paraffin to provide a total of four experiments to compare the average temperature evolution and exergy efficiency. A theoretical framework for exergy analysis give away that use of nano composites in PCMs will improve efficiency rather than a single nanomaterial. However, to assess capability of this system to integrate with solar water heater, if there is no solar radiation limitation, NCPCM with 1.2% wt. will be a better choice with higher cylinders diameter (HD-Cylinders). Neverthless, for climates with limited time in storage energy, NCPCM with 1.2% wt. and lower cylinders diameter (LD-Cylinders) is our best suggestion for maximum efficiency that can be used during the peak solar energy period. Therefore, by considering NCPCM and integrating this novel study with solar technologies as a reliable heat source, outline is an excellent way for saving energy consumption in buildings at any remote area.

Impact of crude oil components on acid sludge formation during well acidizing

Matrix acidizing is one of the most viable options for opening up the clogged tortuous passages in near wellbore region which would lead to improved crude oil production. Nonetheless, the incompatibility of stimulation and reservoir fluids may result in further formation damage i.e., acid sludge. Sludge formation is a highly complex process in which the role of crude oil components is not well understood. In this study, the effect of aromatic and paraffinic components of crude oil on acid sludge formation has experimentally been investigated. For doing so, synthetic oil was used to isolate the impact of individual components of crude oil. Furthermore, the influence of polarity of solvents including DMF, acetone, THF, dichloromethane and toluene was discerned as well as type and concentration of asphaltene and different ratios of acid to synthetic oil mixture. The results showed that a paraffinic synthetic oil would be more susceptible to sludge formation than the aromatic one. Increased polarity of solvents from 2.4 for toluene to 6.4 for DMF resulted in more sludge formation from 15 to 231% and 42–175% for the same synthetic oil but for two asphaltenes, respectively. Acid to mixture ratio (AMR) showed to have a considerable implication on sludge formation. Increasing asphaltene concentration from 5000 to 15,000 ppm caused the increment of 1–3% in sludge content. This implied that asphaltene concentration in the synthetic oil had no considerable effect on the acid sludge formation in the absence of the other constituents of crude oil such as resin.

Preparation and Analysis of Sheath-Core Intelligent Thermo-Regulating Fiber.

In this work, a skin–core composite intelligent temperature-adjusting fiber was prepared using the composite melt spinning method, with polypropylene as the skin layer and T28-type paraffin as the core layer, in order to obtain clothing fibers with a bidirectional temperature adjustment function. A differential scanning calorimeter was used to test the phase-change latent heat of fibers with different amounts of paraffin injections, and an infrared thermal imager was used to monitor the skin–core composite intelligent temperature-adjusting fiber bundles and ordinary polypropylene fiber bundles under the same heating and cooling conditions. The temperature of the fiber bundle was considered to be a function of time. The results showed that with the increase in the amount of the paraffin injections, the proportion of the paraffin component in the fiber and the latent heat of the fiber phase transition also increased. When the paraffin injection amount was 1.5 mL/min, the melting enthalpy and the crystallization enthalpy reached 65.93 J/g and 66.15 J/g, respectively. Under the same conditions, the heating speed of the intelligent temperature-adjusting fiber bundle was found to be slower than that of the ordinary polypropylene fibers, and the maximum temperature difference between the two reached 8.0 °C. Further, the cooling speed of the former was also observed to be slower than that of the latter, and the maximum temperature difference between the two reached 6.7 °C.

Phase transition mechanisms of paraffin in waxy crude oil in the absence and presence of pour point depressant

Molecular dynamics simulations were employed to reveal the phase change mechanisms of paraffin wax in a multiphase system of crude oil comprised of oil, paraffin wax, bitumen, and water. Simulation results revealed that in the absence of a pour point depressant, paraffin crystals intertwined and aggregated to form “three-dimensional networks” that are difficult to dissolve in the oil phase when the temperature is below the wax-out point of paraffin. By comparing three different paraffin components, (n-octadecane [n-C18]); n-octadecane + n-octadecane (n-C18+n-C28); n-octadecane + n-hexadecane n -C18+n-C36), we found that the viscosity and specific heat capacity of the system and phase transition temperature increased with the chain length of paraffin molecules. It was further revealed that the addition of pour point depressant molecules (i.e., polyethylene-vinyl acetate polymer) can prevent the mutual eutectic between paraffin molecules from forming insoluble three-dimensional networks, which instead leads to homogeneously distributed paraffin crystals. In addition, the homogeneously distributed paraffin crystals have a smaller viscosity and lower phase transition point compared to those that are untreated. Our novel discoveries provide theoretical guidance for solving practical engineering problems facing crude oil delivery.

ReaxFF Molecular Dynamics Simulation of the Cracking of Components of Vacuum Gasoil in the Presence of a Nickel Nanocluster

ReaxFF molecular dynamics simulation of the cracking of the paraffin, naphthene, and aromatic components of vacuum gasoil with and without a Ni468 nanoparticle is performed. It is found that the observed routes of destruction of hydrocarbons under thermal action do not contradict the real mechanisms of thermal cracking; the enthalpies of the thermal destruction reactions of the model components obtained in ReaxFF with the CHO and NiCH force fields correlate with those determined via quantum chemistry in the ub3lyp/6-31g(d,p) DFT approximation. The mechanisms of adsorption and destruction of the paraffin, naphthene, and aromatic components of vacuum gasoil on the surface of a Ni468 nanoparticle are studied, based on the results from ReaxFF molecular dynamics simulation. Their enthalpies of adsorption and dehydrogenation are calculated, along with the activation energies of dehydrogenation on the surface of a nickel nanoparticle. Cracking in a multicomponent system consisting of 93 hydrocarbon molecules and a Ni468 nanocluster is simulated, and all routes of the destruction of the initial hydrocarbons are determined.

3D printed ABS/paraffin hybrid rocket fuels with carbon dots for superior combustion performance

In this research, the combustion performance of a novel, composite hybrid rocket fuel grain composed of Acrylonitrile Butadiene Styrene (ABS) and Paraffin was investigated to understand the effects of incorporation of a novel nanomaterial: gel-like carbon dots (CDs), into the paraffin component. ABS fuel grains with straight ports were 3D printed and used as molds into which base and 1 wt% CD-loaded paraffin materials were casted separately. For control, pure ABS fuel grains were also printed. All fuel grains were exposed to ballistic tests using the lab-scale test setup where gaseous oxygen (GOX) was employed as oxidizer. Test results exhibited that ABS/CD-loaded paraffin fuel grains manifested a maximum combustion efficiency and regression rate of 88% and 1.29 mm/s, which marked enhancements of about 8.5% and 11% compared to ABS/pure paraffin fuel grains, respectively. Despite the compromise in the mechanical properties, the enhancement in combustion characteristics of CD-loaded fuel grains was attributed to lower viscosity, higher particle entrainment, specific surface area and catalytic activity

Protein-affinity guided identification of chlorinated paraffin components as ubiquitous chemicals

Chlorinated paraffins (CPs) have been extensively examined to identify their components. Short-chain CPs with a carbon number of 10–13 have been strictly restricted or banned due to their addition to the list of Persistent Organic Pollutants in the world. However, more constituents with potential toxicities in these complicated mixtures are still unclear. In the present study, a purification method based on the protein affinity of thyroid hormone-related proteins (transthyretin and thyroid receptor) was established. The protein-based affinity extraction coupled with high-throughput scanning successfully discover a new group of chlorinated compounds (CP(O2)) in commercial CP mixtures. The CP(O2)s were purified from the commercial mixtures and identified to be chlorinated fatty acid methyl esters (CFAMEs) with a carbon chain length of 17–19 and 3–11 chlorines by a combination of liquid-liquid extraction, hydrolysis, Fourier transform infrared spectrometry and Orbitrap mass spectrometry. The newly identified CFAMEs were found to be ubiquitous in the environmental matrices, and concentration ratios of ∑CFAMEs/∑CPs ranged from 0.01 to 35 in air, soil and food samples. CFAMEs were also detected in blood samples of general populations, and accumulated in humans through dietary uptake. CFAMEs can compete with T4 for binding TTR with higher potencies than CPs, possibly leading to disruptions of thyroid hormone homeostasis.

Comparison of Dimethylformamide with Dimethylsulfoxide for Quality Improvement of Distillate Recovered from Waste Plastic Pyrolysis Oil

As a part of improving the quality of the distillate (distilling temperature 120–350 °C) recovered from waste plastic pyrolysis oil (WPPO) by simple distillation, the enrichment of paraffin components present in the distillate was compared by the equilibrium extraction of dimethylformamide (DMF) and dimethylsulfoxide (DMSO). Regardless of the solvent used, the concentration increase rate of the paraffin component in the raffinate relative to the raw material was reduced by increasing the mass fraction of water in the solvent in an initial state. On the other hand, it increased by increasing the mass ratio of the solvent to the raw material in an initial state. The enrichment performance of paraffin component in raffinate recovered by DMF was higher than that by DMSO under the same experimental conditions. Furthermore, the two solvents were compared by adding color and the waxing phenomena of recovered raffinate to assess the enrichment performance of paraffin components.

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.

Temperature-dependent thermal and mechanical properties of flexible functional PDMS/paraffin composites

As phase change functional polymer composites, polydimethylsiloxane (PDMS) and paraffin composites exhibit excellent performance on temperature dependent thermal and mechanical properties. In this paper, PDMS/paraffin composites with uniform microstructure are prepared by the melting mixing method with paraffin as filler and PDMS as matrix. The modification of PDMS by paraffin components owns both advantages on excellent flexibility and heat absorption capacity. Systematic experiments results are performed to illustrate the DSC specter, stress-strain curves and other properties varying with temperature. The obtained composites can be an ideal material for soft thermal management substrate of flexible electronics or phase change heat sink of batteries and this study might be helpful for the design and fabrication in the wide potential applications.

Thermovolumetric and thermogravimetric analysis of diesel S10

The volatility characteristic of diesel fuel represents one of the most important properties, directly influencing its ignition temperature, thus being an important information for handling and storage safety. The ASTM D86 standard test method is the most commonly used to evaluate the volatility of a fuel at ambient pressure, being used in this work to analyze a diesel S10 from a Brazilian refinery. Thermogravimetric (TG) analyses and density determinations of the ASTM D86 distillation collected fractions of a diesel S10 were performed. TG analyses were accomplished in open platinum pans and in aluminum pans sealed with pinhole lids, from room temperature to 580 °C at a heating rate of 10 °C min−1, using 50 mL min−1 of nitrogen, as the purge gas. Densities were measured from the respective masses and volumes of the collected fractions, which were used to obtain the corresponding distillation thermogravimetric (TG) and thermovolumetric (TV) curves, as a function of respective boiling temperature. The ASTM D86 results are quite like those obtained by TG/DTG curves of diesel S10, performed in sealed pans with pinhole lids. Due to the density evolution of the collected condensed fractions, the shape of the TV curve when compared to the TG curve may indicate the presence or absence of some typical organic classes usually present in diesel composition, which in the present case indicate that it is composed mainly by paraffinic components.

Simulation of the Supramolecular Structure of Petroleum Disperse Systems

The formation of predominant structures of supramolecular entities in highly dispersed colloidal systems, the dispersion phase of which is represented by hydrocarbons, has been studied using molecular mechanics (MM+) simulation. The character of structuring in both individual groups of molecules and their mixtures yielding energetically most stable associates of supramolecular structures has been investigated for compounds taken to model paraffinic, naphthenic, and asphaltenic petroleum components. It has been shown that the number of identical molecules (n) in the associates is limited. For example, asphaltene molecules form an associate with an ordered (graphite-like) supramolecular structure at n ≈ 5–10. Consideration of a mixture of three components with regard to the values of intermolecular interaction energy EIMI shows that in colloidal solutions, asphaltenes form a core to which naphthenic and paraffin hydrocarbons are coordinated.

Technology Focus: Oilfield Chemistry (September 2018)

Technology Focus The last 3 years have seen an unprecedented increase in paraffin-related challenges in the world of production chemistry. The industry is producing more-challenging crude oil as the production of light, sweet, and easy-to-treat crude declines. The new crudes coming on stream contain more-complex combinations of paraffinic components. We are aware of the bimodal distribution of paraffin displayed nicely in high-temperature gas chromatography of, for example, Eagle Ford crude oil, which shows a double peak distribution of paraffin. Some of the more-recent publications highlighted are using more-advanced analytical techniques to characterize crude oil because heavier paraffin components are not detectable by classical methods. Characterization using techniques such as nuclear magnetic resonance and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry are detecting paraffin chains in excess of C100 and determining a trimodal distribution of paraffin in crude oil that is difficult to treat using today’s technology, thus requiring a change in approach and thinking for the production chemist. Such crudes are being developed today—crude oils from some of the more extreme shale plays around the world such as the Montney formation in British Colombia, Canada; Vaca Muerta in Argentina; East African crude oils of Uganda, Chad, and Kenya; and crude oils in the Far East such as those in Indonesia and Vietnam. The current chemical technology begins to reach its limit of functionality in a crude oil that contains paraffin chains of C75+ in length. The featured papers give some insights into the work under way to elucidate the structure performance relationships between inhibitors and crude oils containing these higher paraffinic species. Much work remains in order to develop more-effective solutions and strategies for these incredibly challenging and highly paraffinic crude oils. The featured papers summarize some of the state-of-the-art techniques to determine the true nature of paraffin deposition from these bi- and trimodal crude oils as well as advanced techniques to truly characterize and treat produced fluids and recovered solids samples. Readers are encouraged to research the recommended additional reading and take some time to delve into the references contained in these papers. This literature contains an extensive review of the history and current state of the art in paraffin science for the oilfield chemist and engineer. Recommended additional reading at OnePetro: www.onepetro.org. OTC 27855 Work Flow To Evaluate Wax-Deposition Risk Along Subsea Production Systems by O. Coronado, Genesis, et al. OTC 28714 Cold-Finger Benchmarking Study for Paraffin-Inhibitor Selection by Yun Peng, Shell, et al. SPE 187252 Investigating the Performance of Paraffin Inhibitors Under Different Operating Conditions by Anshul Dubey, The University of Tulsa, et al.

Ignition delay measurements of a low-octane gasoline blend, designed for gasoline compression ignition (GCI) engines

A blend of low-octane (light and heavy naphtha) and high-octane (reformate) distillate fuels has been proposed for powering gasoline compression ignition (GCI) engines. The formulated ‘GCI blend’ has a research octane number (RON) of 77 and a motor octane number (MON) of 73.9. In addition to ∼64 mole% paraffinic components, the blend contains ∼20 mole% aromatics and ∼15 mole% naphthenes. Experimental and modeling studies have been conducted in this work to assess autoignition characteristics of the GCI blend. Ignition delay times were measured in a shock tube and a rapid comparison machine over wide ranges of experimental conditions (20 and 40 bar, 640–1175 K, ϕ = 0.5, 1 and 2). Reactivity of the GCI blend was compared with experimental measurements of two surrogates: a multi-component surrogate (MCS) and a two-component primary reference fuel (PRF 77). Both surrogates capture the reactivity of the fuel quite well at high and intermediate temperatures. The MCS does a better job of emulating the fuel reactivity at low temperatures, where PRF 77 is more reactive than the GCI blend. Ignition delay times of the two surrogates are also simulated using detailed chemical kinetic models, and the simulations agree well with the experimental findings. The results of rate-of-production analyses show important role of cycloalkane chemistry in the overall autoignition behavior of the fuel at low temperatures.

Initial reactivity differences between a 3-component surrogate model and a 24-component model for RP-1 fuel pyrolysis evaluated by ReaxFF MD

This work attempts to investigate initial reactivity for pyrolysis of a rocket propellant fuel (RP-1) by reactive molecular dynamics simulations with ReaxFF force field. The initial reactivity differences between a 3-component surrogate model and a more complex 24-component model have been observed in a series of heat-up and isothermal pyrolysis simulations performed using the GPU-enabled code GMD-Reax. The RP-1 conversion in the 3-component surrogate is slower than that of the 24-component model. The maximal weight fraction difference for RP-1 consumption can be up to 21.2% in heat-up simulations and 22.3% in isothermal simulations. The reaction analysis facilitated by the code VARxMD further reveals the differences of pyrolysis intermediates, products, and reaction pathways between the two RP-1 models. Normal paraffin reactions are similar between the two RP-1 models owing to the similar fuel structures of normal alkanes. For branched paraffin reactions, the pyrolysis of the multi-branched fuel component of iso-cetane in the 3-component surrogate will produce 2-methylpropene, which is not a major pyrolysis product in the 24-component model mainly due to lack of quaternary carbon with methyl side chains in the branched paraffin components. Compared to the reactions of methylcyclohexane, the only cycloparaffin in the 3-component surrogate, more versatile ring opening reactions of cycloparaffins can occur in the 24-component model that will generate more dienes and cyclohexene from the double-ring fuel structures. This work suggests that the reactive molecular dynamics simulations of multi-component model with rich chemical structures closer to real fuel components have the potential as an alternative approach for evaluating reactivity in fuel pyrolysis.