Mixture Of Propane Research Articles

The Investigation of Soot Free Length of Jet Flame of Propane and Carbon Dioxide Gas Mixture

ABSTRACT This study investigated the evolution of soot free length of turbulent jet flame with different mass flow rates of propane and carbon dioxide (CO2) experimentally. The nozzles with diameters of 2, 3, and 4 mm are used. The experimental results show that the soot free length increases with the increment in the concentration of CO2 since less soot will be produced, at the same time, soot free length fraction as the concentration of CO2 in the mixed fuel increases, it first shows a slight raise, and then increases rapidly. The correlation between modified Reynolds number and the soot free length has been developed. A correlation between soot free length fraction and the mixture fraction of propane and CO2 has been developed based on the analysis of laminar flame burning speed theory.

Simulation of LPG tank truck leakage and explosion accident based on CFD

Road transportation of hazardous chemicals has a high risk and is likely to cause serious road traffic accidents. In this paper, the most common LPG tanker in hazardous chemical transportation is taken as the research object. Based on theCFD method, we used FLACS software to simulate LPG tank car accident in Italy. The leakage process of LPG tank car after leakage was simulated, and the diffusion process of propane and butane mixture in one minute when the accident occurred. It was further analyzed that the leakage material exploded when it encountered the ignition source, and the shock wave overpressure was the highest at 2.5 seconds after the explosion, with the shock wave pressure exceeded 0.26MPa. Also, the attenuation of theblast wave is higher in the area far away from the explosion source. The research results can provide effective data support for on-site emergency disposal and personnel evacuation of similar accidents.

Long gap spark discharge ignition using a boron-doped diamond electrode

A long gap discharge offers an efficient method for achieving stable ignition in lean fuel/air mixtures, because it can reduce the heat loss to the electrodes, achieve efficient electrical energy transfer from the ignition coil to the discharge plasma, and reduce the initial flame curvature by converting the geometry of the ignition from a point to a line. However, the formation of such discharge requires increased discharge voltage to compensate for the reduction in the electric field between the electrodes, and this is not easily achieved in practice. Since the Townsend discharge criteria depend not only on the electron multiplication coefficient (α coefficient) but on the secondary electron emission (γ-process), we focused on the latter to reduce the discharge threshold voltage. In the present study, for the first time, B-doped diamond (BDD), which has a larger secondary electron emission coefficient than the metals used in conventional spark discharge ignition, was utilized as the cathode material, and its discharge and ignition characteristics were investigated. Under the same conditions, use of a BDD cathode resulted in a lower discharge threshold, greater discharge energy, less discharge energy variation, and more rapid flame development, than in the case of a metal cathode. The influence of the cathode material on discharge threshold suggests that the breakdown mechanism of ignition-coil spark discharge is based on Townsend discharge. To elucidate the effect of gap length, the temporal development of flame growth, using the same discharge energy in methane and propane mixtures, was compared between ignition with a short gap discharge with a metal cathode and long gap discharge with a BDD cathode. With a long gap discharge, only the flame growth of lean propane-air mixtures was accelerated, while no difference was observed in the case of lean methane or relatively rich propane mixtures, suggesting the effectiveness of long gap discharge ignition for mixtures with a large Lewis number, due to the small curvature of the initial flame kernel.

Exergy and exergoeconomic analyses of serial and bypass two-stage compression on the household refrigerator-freezer and replacement of R436A refrigerant

In this research, the performance of serial two-stage compression (STC) cycle and bypass two-stage compression (BTC) cycle on the household refrigerator-freezers is tested in the laboratory. Then, based on the results of the experiments, exergy, exergoeconomic analyses, and cycle optimization are carried out. Considering that replacing refrigerants in household refrigerator-freezers is one of the approaches to increase the performance and environmental impact of these systems, R436A refrigerant (46% Isobutene and 54% Propane mixture) is used and analyzed to replace previous refrigerants. Finally, the multi-objective optimization of the mentioned cycles is performed with both refrigerants. For analyses, two models of refrigerator-freezers with different cycles are used (STC cycle with R134a refrigerant and BTC cycle with R-600a refrigerant). In both models, two evaporators for refrigerator-freezer compartments are used. International standards (IEC 62552) are used to test refrigerator-freezers. MATLAB and REFPROP 9.1 software are used to model the systems. According to the results of the analyses, the STC cycle with R436A refrigerant has more total exergy destruction rate (0.727 kW) compared to R134a refrigerant. In the BTC cycle, in which the fresh food compartment (FFC) and freezer compartment (FZC) operate, the total exergy destruction rate with R-600a refrigerant (0.422 kW) is less than with R436A refrigerant. In the case of the BTC cycle in which only the FZC operates, the total exergy destruction rate with R-600a refrigerant (0.455 kW) is less than with R436A refrigerant. The most exergoeconomic factor among cycle equipment is related to the compressor (about 98%). The highest COP value between cycles is related to the STC cycle with R134a refrigerant.

Superficial cryotherapy using dimethyl ether and propane mixture versus microneedling in the treatment of alopecia areata: A prospective single-blinded randomized clinical trial.

To verify and compare the therapeutic efficacy and safety of superficial cryotherapy using dimethyl ether and propane (DMEP) mixture vs. microneedling in the treatment of mild scalp alopecia areata (AA). In a prospective randomized single-blinded clinical trial, 80 patients with clinically evident scalp mild AA were randomly assigned into two groups of 40 patients each. Group (1) was treated by superficial cryotherapy using DMEP in three freeze-thaw cycles of 5s each. Group (2) was treated by microneedling. Both groups were treated every 2 weeks for 6 sessions and followed up for 3months after the last session. Patients were assessed by photographic documentation, trichoscopic evaluation, severity of alopecia tool (SALT) score, and alopecia areata symptom impact scale (AASIS). An excellent response was achieved in 15 (37.5%) of group (1) compared with 14 (35%) of group (2) patients, while a good response was achieved in 23 (57.5%) of group (1) compared with 21 (52.5%) of group (1) patients, with a statistically insignificant difference. The mean SALT score change percentage was a statistically significantly higher in group (2) patients. The mean AASIS change percentage was higher in group (1) patients, but this was a statistically insignificant. In both groups, the mean numbers of trichoscopic signs of AA significantly decreased from baseline to the end of follow-up period. Both therapeutic modalities were well-tolerated, with no recurrence after the follow-up period. Both superficial cryotherapy using DMEP mixture, and microneedling are simple, effective, and safe therapeutic options for mild scalp AA, however, microneedling showed higher efficacy.

Studying the Selective Methylacetylene Hydrogenation Reaction in Methylacetylene–Propylene Mixtures on Palladium Oxide Nanocatalysts

Studying the Selective Methylacetylene Hydrogenation Reaction in Methylacetylene–Propylene Mixtures on Palladium Oxide Nanocatalysts

Performance of a single-stage recuperative high-temperature air source heat pump

• A single-stage recuperative high-temperature air source heat pump is developed. • Exergy efficiency of 27.97% is higher than the existed heat pumps. • Discharge pressure is less than 2 MPa at the hot water temperature 91.68 °C. • n-hexane concentration is 52.36% shifted at optimal condition. Heat energy of 75–100 °C is increasingly used in residential and industrial fields. However, conventional single-stage air source heat pumps suffer low efficiency and poor operating conditions when supplying such high-temperature heat energy. To address the challenging problems, a novel single-stage recuperative high-temperature air source heat pump prototype for tap water direct heating was developed and investigated experimentally. The intrinsic characteristic of the recuperative heat pump makes the prototype simple and components easy to gain. The key impacts of the throttle valve opening, refrigerant concentration, and water flow rate on the system performance were revealed and analyzed with the refrigerant mixture of n-hexane and propylene. Results show the excellent thermodynamic efficiency and working condition of the developed heat pump. When heating water from 23.70 °C to 91.68 °C, the system shows its optimal performance with the coefficient of performance, exergy efficiency, and compression ratio 2.83, 27.97%, and 2.86, respectively. Furthermore, based on the experiment data, systematic thermodynamic analysis on optimal condition indicated that the mass fraction of n-hexane in the cycle is about 52.36% shifted against the initial charging proportion of 36%. Finally, after system performance comparison against the CO 2 transcritical heat pump and auto-cascade heat pump, the recuperative high-temperature heat pump shows excellent efficiency and nice operating condition, which proves the developed heat pump a successful and promising application prospect.

Improving the performance of LPG with graphene-nanolubricant in a domestic refrigerator: an artificial intelligence approach

This work investigated the possibility of improving liquefied petroleum gas (LPG) of propane and butane (60:40) mixture with graphene nanolubricant (GN) in a domestic refrigerator system. An artificial intelligence model with Artificial Neural Network (ANN) and Adaptive Neuro-Fuzzy Inference (ANFIS) was also developed to predict the performance of the LPG with graphene nanolubricant in the system and validate it with experimental results. The graphene nanolubricant was investigated in 50–70 g charge of LPG refrigerant. Four Type K thermocouples were attached to the refrigerator components to track the temperature of the system. Two pressure gauges were also attached to the compressor to determine the pressure at suction and discharge of the domestic refrigerator. A digital watt-meter was used to measure the refrigerator’s compressor power consumption. The obtained result showed a higher COP with graphene nanolubricant concentrations. The power consumption and cooling capacity improved within the range of 16.3%–20.1% and 6.4%–19.6% respectively with graphene nanolubricant concentrations. Also, the ANN and ANFIS model predicts the COP of the refrigerator with a Root Mean Square Error (RMSE) value of 0.620 and 0.303 and Mean Absolute Percentage Error (MAPE) of 29.4% and 14.9% respectively.

Phase Diagrams for Ternary Mixtures of Methane, Propane, and Octane for the Low Concentration of Octane

Precision data of the accurate calorimetric measurements of phase equilibria for ternary mixtures of methane, propane, and octane especially for the low concentration of octane have been presented. Based on the experimental data of heat capacity, internal energy, pressure, and temperature derivative of pressure at constant volume, the phase diagrams have been plotted in the range 140–350 K and 0.1–24 MPa. Phase transitions are localized by the finite discontinuities in temperature derivatives of the thermodynamic potentials. Our investigations show that hydrocarbon mixtures for the low concentration of octane split into two phases, the macrophase enriched by methane and propane and the octane-rich microphase. Besides, octane provokes a split of the liquid part of the macrophase into two liquid phases, the octane-rich phase and the octane-lean phase. To prove that all phases are equilibrium phases a cooling mode of measurements is used. At the cooling mode of measurements the same phase transitions as at the heating mode occur. These phase transitions correspond to the formation of the octane-rich microphase and the macrophase enriched by methane and propane. Besides, at the cooling mode of measurements a split of the liquid part of the macrophase into two liquid phases takes place.

Revisiting the extraction and dehydration of ethanol by the hot propane process

Conventional liquid extraction is not a suitable separation method for the recovery and dehydration of ethanol and other light alcohols from aqueous solutions. Condensed non-polar gases like propane and CO2 looked promising as potential solvents. The favorable effect of temperature on the alcohol distribution coefficient of condensed propane led to the development of the hot propane process (HPP) for extraction and dehydration of alcohols. The dehydration of the alcohols took place in the solvent recovery column, thanks to the water entrainment effect of propane. Earlier pilot plant studies confirmed the process feasibility. In the present work, we design mixtures of propane + CO2 and phase conditions that fulfill the key properties of the HPP: (1) good alcohol distribution coefficient in the high-pressure extractor and (2) adequate water entrainment effect in the solvent recovery column.

Isobaric heat capacity measurements of natural gas model mixtures (methane + n-heptane) and (propane + n-heptane) by differential scanning calorimetry at temperatures from 313 K to 422 K and pressures up to 31 MPa

Heat capacities of pure methane (1), propane (2) and n-heptane (3), and binary mixtures of (methane or propane + n-heptane) at n-heptane mole fractions of (0.070 to 0.750), were measured at temperatures (313 to 422) K and pressures (6.00 to 31.10) MPa using a Tian-Calvet-type differential scanning calorimeter with a combined standard uncertainty of (2.20 to 2.68) % (k = 1). The results for pure methane, propane and n-heptane agreed within 2% of the values calculated from reference equations of state (EOS). In contrast, for the two sets of mixtures measured above their cricondenbars, averaged absolute deviations of 4.6%, 3.7% and 1.2% were observed between the measured cp values and those predicted by the GERG-2008, Peng-Robinson (PR) and SAFT-γ Mie EOS, respectively. The divergences of cp from model calculations for the binary mixtures near the critical region were also investigated. The root mean square (r.m.s.) deviations of the measured heat capacities from those calculated using the GERG-2008, PR, and SAFT-γ Mie exhibited relatively large but similar values of 7.1%, 7.4% and 7.2% for [0.850 CH4 + 0.150 n-C7H16] and 9.1%, 6.9% and 8.0% for [0.930 C3H8 + 0.070 n-C7H16]. This work reveals that the SAFT-γ Mie EOS can adequately describe most heat capacity data above the cricondenbar, while none of the models provide reliable predictions near the critical region.

Surrogate models of thermally cracked hydrocarbon fuels at typical pyrolysis temperatures

Construction of surrogate fuel model for thermally cracked fuel holds fundamental importance to its combustion characteristics. In the present study, series of thermal cracking experiments of hydrocarbon fuel were carried out at supercritical pressure. Thermally cracked fuels at three typical pyrolysis temperatures, which covered the low, middle, and high levels of thermal cracking, were selected and analyzed. A formulation method to construct surrogate models for thermally cracked fuels was developed, in which the pyrolysis gas and liquid were considered separately, and then combined by a key parameter of gas-production rate. Laminar burning velocities of the target fuels and their corresponding surrogate models were measured using a constant-volume bomb, and then compared to validate the fidelity of surrogate models. Results show that the pyrolysis gas can be well substituted by a mixture of hydrogen, methane, ethylene, ethane, and propylene. Surrogate models of pyrolysis liquids contain eight large hydrocarbons, taking into account the variations of hydrocarbon classes and carbon number distribution. By changing mole fractions of candidate species, the proposed surrogate models of pyrolysis liquids reasonably match all target properties, including the averaged molecular weight (MW), hydrogen-to-carbon ratio (H/C), lower heating value (LHV), derived cetane number (DCN) and density. Surrogate models of thermally cracked fuels combine those of both pyrolysis gases and liquids, and can accurately predict the laminar burning velocities. With thirteen candidate components and the formulating strategy, the current method is capable of constructing a surrogate model for thermally cracked fuel with a fuel-conversion rate up to 73%.

Comprehensive study on hydrogen production via propane steam reforming inside a reactor

In the proton exchange membrane fuel cells, the required hydrogen must be produced in some way. The power generators in the path of these fuel cells generally include a steam reactor that, through other fuels, provides the needed energy to produce hydrogen. This study investigates a steam reactor powered by propane fuel consisting of a shell and tube heat exchanger. The shell contains a catalyst that receives the mixture of propane and steam, and the tubes embedded inside the reformer contain hot gases that provide a suitable substrate for the reaction. Velocity and temperature fields inside the reformer, species concentration control, and reaction rate are studied. The conversion of reactants and yield of products are investigated according to the reaction rate. The results show that the hydrogen production yield can vary from 77.5 % to 92.2 %. The reaction rate can be controlled by the velocity and temperatures of the hot gases. However, for the T=900 K, full propane consumption is achieved at the reformer outlet.

Polyethylene Pyrolysis Products: Their Detonability in Air and Applicability to Solid-Fuel Detonation Ramjets

The detonability of polyethylene pyrolysis products (pyrogas) in mixtures with air is determined for the first time in a standard pulsed detonation tube based on the measured values of deflagration-to-detonation transition run-up time. The pyrogas is continuously produced in a gas generator at decomposition temperatures ranging from 650 to 850 °C. Chromatographic analysis shows that at a high decomposition temperature (850 °C) pyrogas consists mainly of hydrogen, methane, ethylene, and ethane, and has a molecular mass of about 10 g/mol, whereas at a low decomposition temperature (650 °C), it mainly consists of ethylene, ethane, methane, hydrogen, propane, and higher hydrocarbons, and has a molecular mass of 24–27 g/mol. In a pulsed detonation mode, the air mixtures of pyrogas with the fuel-to-air equivalence ratio ranging from 0.6 to 1.6 at normal pressure are shown to exhibit the detonability close to that of the homogeneous air mixtures of ethylene and propylene. On the one hand, this indicates a high explosion hazard of pyrogas, which can be formed, e.g., in industrial and household fires. On the other hand, pyrogas can be considered as a promising fuel for advanced propulsion powerplants utilizing the thermodynamic Zel’dovich cycle with detonative combustion, e.g., solid-fuel detonation ramjets. In view of it, the novel conceptual design of the dual-duct detonation ramjet demonstrator intended for operation on pyrogas at the cruising flight speed of Mach 2 at sea level has been developed. The ramjet demonstrator has been manufactured and preliminarily tested in a pulsed wind tunnel at Mach 1.5 and 2 conditions. In the test fires, a short-term onset of continuous detonation of ethylene was registered at both Mach numbers.

Reduced mechanism for flames of propane, n‐butane, and their mixtures for application to burners: Development and validation

AbstractPropane, n‐butane, and their mixtures are commonly used as fuels for various applications. Reliable numerical simulations of flames involving these fuels are most essential to study their efficient use in domestic and industrial burners. Such simulations require a suitable reaction mechanism containing the necessary kinetics to predict key combustion characteristics in flames accurately. However, the use of detailed kinetic mechanisms for these computations is formidable in multidimensional simulations, owing to their large sizes. To address this, in this work, a compact mechanism (45 species, 392 reactions) for propane, n‐butane, and their mixtures, suitable for multidimensional simulations is derived and comprehensively validated against available experimental data in flames. The main oxidation pathways retained in this compact model are showcased. One‐dimensional (1D) computations of premixed and nonpremixed flames are carried out using FlameMaster and Chemkin‐Pro. Two‐dimensional (2D) calculations are performed within ANSYS‐FLUENT. Here, multicomponent diffusion, thermal diffusion, and radiation submodels are used. Laminar flame speeds, extinction strain rates, and amounts of major species in premixed flat flames are validated using 1D computations. Temperature and major species in propane and n‐butane jet diffusion flames are verified in 2D simulations. Further, 2D computations using the compact mechanism also predict the laminar burning velocity of premixed flames of n‐butane and propane mixtures established over a Bunsen burner. The ability of the compact mechanism to predict desired targets in premixed and nonpremixed flames is analyzed from a kinetic basis. Validation using 2D simulations demonstrates the usability of the compact mechanism in multidimensional computations.

Combustion of lean fuel mixtures with subcritical streamer microwave discharge

A sub-critical microwave discharge is used to achieve a stable ignition and combustion of lean air-fuel mixtures in a long tube. The microwave discharge is burnt at the presence of initiator with the quasi-optical microwave beam. The resonance way of initiation of a microwave discharge is more effective compared to traditional plasma-assisted ways of ignition and stabilization of combustion. The experimental observations show that ignition and combustion of a lean air and propane mixture in a long tube is achieved at low ignition limit with fuel/air ratio lower than 0.55. The results obtained are useful for design of new and improvement of the existing plasma-assisted technologies in aviation industry.

A low-temperature plasma generator working on nitrogen–propane mixture

A low-temperature plasma generator of a mixture of nitrogen and propane has been developed, with the possibility of supplying propane to the cathode region, to the arc burning zone, and also to the plasma stream below the arc binding zone. The maximum propane flow rate for a given plasmatron design and plasma-forming nitrogen flow rate, at which the arc is stable, was determined. When propane is supplied into the arc binding zone, the decay products are deposited mainly on the electrodes, and when it’s supplied to the anode after the arc binding, the decomposition products are deposited mainly at the anode exit. The study of the microstructure and analysis of the phase composition of the decomposition products of propane were performed.

Pressurized mixture of CO2 and propane for enhanced extraction of non-edible vegetable oil

Vegetable oils in neglected matrices (monguba seeds and immature green coffee beans) were extracted using a mixture of pressurized carbon dioxide (CO2) and propane. The yields, fatty acid profiles, and active compounds in the extracted oils were evaluated employing a Box-Behnken experimental design, considering the effects of temperature (20–60 °C), solvent flow rate (1.5–2.5 mL min−1), and propane amount (10–50%). The maximum yields were 42.83% for monguba oil and 10.83% for immature green coffee oil. Lower temperature (40–60 °C) and a higher propane fraction (50%) led to higher oil yields. Empirical models satisfactorily described the extraction kinetics. Treatment of the data using principal component analysis (PCA) revealed that the conditions that favored extraction of saturated fatty acids impaired the extraction of polyunsaturated fatty acids. Extraction with a mixture of pressurized CO2 and propane resulted in attractive fatty acid profiles and high oil yields, while preserving the active compounds.

Molecular Resolution into the Nucleation and Crystal Growth of Clathrate Hydrates Formed from Methane and Propane Mixtures

Type II clathrate hydrates are prevalent in numerous applications including gas production, gas storage, and seawater desalination. However, less focus has been given to understanding the molecular...

Propane to olefins tandem catalysis: a selective route towards light olefins production.

On-purpose synthetic routes for propylene production have emerged in the last couple of decades in response to the increasing demand for plastics and a shift to shale gas feedstocks for ethylene production. Propane dehydrogenation (PDH), an efficient and selective route to produce propylene, saw booming investments to fill the so-called propylene gap. In the coming years, however, a fluctuating light olefins market will call for flexibility in end-product of PDH plants. This can be achieved by combining PDH with propylene metathesis in a single step, propane to olefins (PTO), which allows production of mixtures of propylene, ethylene and butenes, which are important chemical building blocks for a.o. thermoplastics. The metathesis technology introduced by Phillips in the 1960s and mostly operated in reverse to produce propylene, is thus undergoing a renaissance of scientific and technological interest in the context of the PTO reaction. In this review, we will describe the state-of-the-art of PDH, propylene metathesis and PTO reactions, highlighting the open challenges and opportunities in the field. While the separate PDH and metathesis reactions have been extensively studied in the literature, understanding the whole PTO tandem-catalysis system will require new efforts in theoretical modelling and operando spectroscopy experiments, to gain mechanistic insights into the combined reactions and finally improve catalytic selectivity and stability for on-purpose olefins production.