Mixture Of Propane Research Articles

An experimental investigation of flame and autoignition behavior of propane

Autoignition delay time data are one important means to develop, quantify, and validate fundamental understanding of combustion chemistry at low temperatures (T<1200 K). However, low-temperature chemistry often has higher uncertainties and scatter in the experimental data compared with high-temperature ignition data (T>1200 K). In this study, autoignition properties of propane and oxygen mixtures were investigated using the University of Michigan rapid compression facility in order to understand the effects of ignition regimes on low-temperature ignition data. For the first time for propane, autoignition delay times were determined from pressure histories, and autoignition characteristics were simultaneously recorded using high-speed imaging of the test section through a transparent end-wall. Propane mixtures with fuel-to-O2 equivalence ratios of ϕ = 0.25 and ϕ = 0.5 and O2-to-inert gas molar ratios of 1:3.76 were studied over the pressure range of 8.9 to 11.3 atm and the temperature range of 930 – 1070 K. The results showed homogeneous or strong autoignition occurred for all ϕ = 0.25 experiments, and inhomogeneous or mixed autoignition occurred for all ϕ = 0.5 experiments. While a limited temperature range is covered in the study, importantly the data span predicted transitions in autoignition behavior, allowing validation of autoignition regime hypotheses. Specifically, the results agree well with strong-autoignition limits proposed based on the Sankaran Criterion. The autoignition delay time data at the strong-ignition conditions are in excellent agreement with predictions using a well-validated detailed reaction mechanism from the literature and a zero-dimensional modeling assumption. However, the experimental data at the mixed autoignition conditions were systematically faster than the model predictions, particularly at lower temperatures (T< ~970 K). The results are an important addition to the growing body of data in the literature that show mixed autoignition phenomena are important sources of the higher scatter observed in the low-temperature autoignition data for propane and other fuels. The results are discussed in terms of different methods to capture the effects of pre-autoignition heat release associated with mixed autoignition conditions and thereby address some of the discrepancies between kinetic modeling and experimental measurements.

Isobaric heat capacities of a methane (1) + propane (2) mixture by differential scanning calorimetry at near-critical and supercritical conditions

Isobaric heat capacity data are needed to test and improve thermodynamic models of natural gas over wide ranges of temperature and pressure. Measurements are reported here at temperatures between (184 and 421) K and pressures between (5 and 32) MPa for supercritical mixtures of methane (1) + propane (2) at x1 = 0.950 (±0.005). Estimated relative uncertainties in the measured heat capacities range from (1.8 to 4.5) %. In addition, measurements at temperatures of (184, 190, 197, 203 and 209) K were performed at pressures (1.67 to 2.39) MPa higher than saturation conditions to estimate the heat capacity of the mixture at the bubble point. The binary mixture data were compared with the predictions of three models: the Groupe Européen de Recherches Gazières (GERG) 2008 multi-parameter equation of state (EOS), the Peng-Robinson (PR) EOS used widely by chemical engineers, and the Statistical Associating Fluid Theory (SAFT)-γ Mie EOS incorporating group contributions. Among the three models, the PR EOS was found to describe the heat capacity values best. A brief investigation indicated that the Joback and Reid method that the SAFT-γ Mie EOS is based on fails to accurately predict the ideal gas heat capacity of methane at cryogenic temperatures, while the inaccuracy of the GERG-2008 EOS stems from the residual part of the methane (1) + propane (2) mixing functions.

Evaluation of Empirical Evidence Against Zone Models for Smoke Detector Activation Prediction

A series of experiments were conducted in a large room to generate data to assess the accuracy of computer fire model predictions of detector activation time. A comparison between experimental measurements and zone model predictions of the detector activation in the Consolidated Fire and Smoke Transport model (CFAST) version 7.4.3 were made. The experimental room was 11.0 m by 7.3 m by 3.7 m high with a single opening 2.44 m high and 1.83 m wide centered in a short wall. Two ceiling configurations were examined, a flat ceiling and a flat ceiling with two 0.30 m wide and 0.30 m deep solid beams. The fire source was a gaseous fuel burner fed with different mixtures of propane and propene that produced soot yields ranging from 0.010 gsoot/gfuel to 0.072 gsoot/gfuel and a fuel flow ramp time that ranged from 30 s to 1800 s. The heat release rate profile reached a nominal maximum value of 30 kW. The activations of two different models of photoelectric smoke detectors and a single ionization smoke detector, each with a range of alarm set points and installed at various locations on the ceiling, were recorded. Predictions of the various smoke detector activation times were made in CFAST with the temperature approximation method, and a fixed smoke detector concentration method for photoelectric detector activations. Predictions with the smoke detection method were better than the temperature approximation method over the range of fire scenarios examined. Predictions of smooth ceiling experiments were generally better than the beamed ceiling experiments.

Inhibition effect of methanol addition on carbon deposition in propane pyrolysis

Methanol-mixed fuels consisting of methanol, propane, and a small amount of auxiliary solvent are widely used as inexpensive industrial fuels, but the carbon deposition in the pyrolysis of this fuel seriously restrains its popularization. This paper studied the characteristics of gaseous products and carbon deposition in the pure propane and methanol-propane mixture pyrolysis experimentally, analyzed the effect of methanol addition on the reaction path of propane pyrolysis and production rate of key species by using detailed reaction mechanism. Results show that methanol addition can restrain C2H4 converting to C2H2 in the later stage of pyrolysis. The carbon deposition rate and particle diameter increase exponentially with the increase of reaction temperature in both pure propane and methanol-propane blend pyrolysis. Methanol addition can significantly reduce the carbon deposition rate and particle diameter. The reaction path analysis indicates that the main reaction paths forming benzene are C3H3 → A1 and C4H4 → I-C6H6 → A1, and C3H3 is a key specie to form benzene. The pyrolysis of methanol-propane mixture generates more H2 and H than that of pure propane pyrolysis, which makes most C3H6 convert to C2H4, reduces the amount of C3H3 and suppresses the conversion of C2H4 to C2H2. And then the amount of benzene is reduced significantly and the generation of subsequent PAHs and carbon deposition is inhibited. Lots of H2 also restrains the hydrogen abstraction from benzene resulting in the delay of the formation of PAHs and carbon deposition. This study is of great significance to research the soot formation in hydrocarbon combustion with alcohol fuel.

Analytical Solution for The Toluene and Mixture of Toluene and n-Propanol in The Biofilm Using ADM

In this paper, biofiltration of a mixture of propane and toluene in a biofilter packed with a compost—woodchip mixture has been considered. The purpose of this article is based on solving the nonlinear toluene and propanol equations of the biofilm problem by the Adomian decomposition method (ADM). The conclusion of the numerical and analytical results of the concentration of the propanol and toluene are not only to an accuracy of them it is an understanding their procedure for solving process. The error percentage between Adomian decomposition method (ADM) and numerical results is observed. Furthermore, the reported analytical result is useful in future modification of mathematical modeling of the biofilter.

Production of highly superheated steam by cyclic detonations of propane- and methane-steam mixtures with oxygen for waste gasification

It is proposed to produce highly superheated steam (HSS) for environmentally friendly steam assisted gasification of organic municipal and industrial wastes using cyclic detonations of ternary propane/methane–oxygen–steam mixtures. Systematic experiments to determine the detonation limits of such mixtures in terms of steam dilution have been conducted. The experiments are performed in an innovative pulse-detonation steam superheater (PDSSH) with cyclic detonations of ternary mixtures at variation of fuel-to-oxygen equivalence ratio (from 0.14 to 1.77 in propane mixtures and from 0.3 to 1.84 in methane mixtures) and steam volume fraction (from 0 to 0.7) at normal atmospheric pressure. The experiments are supplemented by thermodynamic calculations. Cyclic detonations of ternary propane/methane–oxygen–steam mixtures are proved to generate HSS with temperature exceeding 2250 K, when expanded to the atmospheric pressure. The detonation products of stoichiometric ternary mixtures under consideration can contain up to 80% HSS and up to 17% CO2 with trace amounts of CO, O2 and H2. As a result of deep processing (gasification) of organic wastes by such products a gaseous mixture of CO and H2 is obtained, which can be further used as a fuel gas for PDSSH operation, heat/electricity production, and as a raw material for production of methanol and synthetic motor fuels. Due to periodic filling of the PDSSH with the cool ternary gas mixture, the temperature of PDSSH walls and inner elements increases insignificantly, so that conventional (not heat-resistant) construction materials can be used for its production.

Experimental Study on Characteristics of Ignition and Meso-scale Flames for Hydrogen added Propane Mixtures in Isotropic and Homogeneous Turbulence

Experimental Study on Characteristics of Ignition and Meso-scale Flames for Hydrogen added Propane Mixtures in Isotropic and Homogeneous Turbulence

On the oscillating flame characteristics in nonpremixed laminar coflow-jets: An experimental and numerical study

This study investigates the characteristics of oscillating lifted flames in laminar coflow-jets experimentally and numerically by varying both fuel density (by varying propane and n-butane mixtures) and coflow density (by diluting air with N2/He mixtures). Two different lifted flame oscillation behaviors are observed depending on these parameters: oscillating tribrachial lifted flame (OTLF) and oscillating mode-change lifted flame (OMLF), where a rapid increase in flame radius is observed. The regimes of the two flames are identified from experiments, which shows that OMLF occurs only when the effect of the negative buoyancy on the flow field by the fuel heavier than air becomes significant at low fuel jet velocity. OMLFs are also identified to distinguish OTLF regime from flame extinction, which implies that an OMLF can be extinguished when the positive buoyancy becomes weak, losing its stabilizing effect, or when the negative buoyancy becomes strong, further enhancing its destabilizing effect. Transient numerical simulations of both OTLF and OMLF reveal that the OMLF occurs by a strong toroidal vortex and a subsequent counterflow-like structure induced by relatively-strong negative buoyancy. Such a drastic flow redirection significantly changes the fuel concentration gradient such that the OMLF changes its mode from a tribrachial flame mode (decreasing edge speed with fuel concentration gradient) to the premixed flame-like transition mode when the fuel concentration gradient becomes very small (increasing edge speed with fuel concentration gradient). Again, a tribrachial flame mode is recovered during a rising period of flame edge and repeats an oscillation cycle.

CFD investigation of natural gas leakage and propagation from buried pipeline for anisotropic and partially saturated multilayer soil

The incident of natural gas leakage from buried pipelines in the soil, due to the financial and environmental consequences has become one of the most serious concerns, especially in urban areas. The main objective of the present study is the development of a three-dimensional numerical model to investigate the rate of leakage and propagation of natural gas from buried pipes with respect to the real soil conditions. The intended conditions include soil anisotropy in three directions, soil stratification and layering, time-dependent moisture content of soil matrix in each layer, and slope of soil layers. These conditions are important due to their influence on leakage velocity and dispersion process, which are not investigated up to now in literature. The used mechanical and hydraulic properties of the soils in the model are based on the database of soil samples which collected from different provinces of Iran. Despite many studies that have assumed natural gas as a pure substance with ideal behavior, the presented model assumes natural gas to be the mixture of methane (90%), ethane (7%), and propane (3%) with deviation from ideality. The equation of state applied to the model is the Soave modification of Redlich-Kwong. The results indicate that hole diameter alteration on the pipeline from 10 to 50 mm causes 86.51% incremental impact in discharge rate. Also, for the dry soil case, there is no gradient of gas concentration in the soil. For multilayer soils with different slope, gas propagates along the slope gradients. Evaluation of relative concentration of thiol in comparison with the concentration of other gas components in different soil contaminated areas indicates that up to 6.7% of the thiol is adsorbed onto soil particles’ sites.

Gas-Phase Oxidation of a Propane–Propylene Mixture by Nitrous Oxide

The present study focuses on a new method for obtaining C2–C3 carbonyl compounds (ketones and aldehydes) by the gas-phase selective oxidation of a propane–propylene mixture using nitrous oxide (N2O...

Gallate-Based Metal–Organic Frameworks for Highly Efficient Removal of Trace Propyne from Propylene

Purification of propylene from the propyne (C3H4)/propylene (C3H6) mixture is a significant and challenging process in the chemical industry. Nowadays, the removal of propyne from propylene mainly ...

Studies of the TNT equivalence of propane, propane/oxygen, and ANFO

The TNT equivalences of equal masses of propane, a stoichiometric mixture of propane and oxygen, and ammonium-nitrate–fuel-oil (ANFO) were calculated based on the peak hydrostatic and dynamic pressures, the hydrostatic and dynamic pressure positive-phase impulses, and the positive-phase integrated work flux. It was assumed that the propane had been dispersed as a vapour/droplet cloud to form a stoichiometric mixture with atmospheric oxygen before detonation. This is the objective for fuel–air weapons and the worst-case scenario for accidental propane explosions such as boiling liquid expanding vapour explosions. The TNT equivalences of propane/oxygen and ANFO, which have energy yields less than TNT, show little variation when calculated using the different blast wave physical properties. In contrast, the equivalences for propane, which has a significantly higher energy yield than TNT, show a broad range of values, with those based on the impulses being significantly larger than those based on the peak values. The equivalence based on the positive-phase integrated work flux is intermediate between the peak and impulse values. The reasons for these differences are illustrated and discussed.

Extended calibration of a vibrating tube densimeter and new reference density data for a methane-propane mixture at temperatures from (203 to 423) K and pressures to 35 MPa

In this work, the lowest operational temperature of a commercial vibrating tube densimeter (VTD) calibrated using a robust physically-based model was carefully extended down to 203 K. The VTD was calibrated under vacuum and filled with pure gaseous methane and liquid propane as calibration reference fluids at temperatures from (203 to 423) K and pressures up to 35 MPa. The calibration parameters were obtained by linear and nonlinear regression of the calibration data (period of oscillation, temperature and pressure) to the physically-based calibration model. The relative deviations between the fitted densities of methane or propane and those predicted by the corresponding default reference equations of state were between (−0.56 to 0.60) % and the relative root mean square error was 0.30%. This wide-ranging calibration model was then employed for single-phase density measurements of a 0.95 methane + 0.05 propane mixture at a temperature of 203 K and pressures up to 35 MPa. Additionally, two sets of measurements at pressures approaching the bubble point at (203 and 208) K were completed. The measured densities ranged from (243 to 369) kg·m−3, with combined standard relative uncertainties between (0.31 and 0.42) %. The relative deviations of the measured densities from those calculated using the GERG-2008 equation of state spanned between (−0.5 to 0.4) %. This work demonstrates the potential of using the physically-based calibration model for VTDs at significantly low temperatures than previously attempted.

Preparation of high-yield multi-walled carbon nanotubes by catalytic decomposition of mixture of natural gas and propylene and their electrothermal properties

Multi-walled carbon nanotubes (MWNTs) with high-yield were prepared by pyrolysis of mixture of natural gas (NG) and propylene (C3H6) over Fe-Ni/Al2O3-MgO catalyst. For C3H6/NG flow rate ratio ranging from 0 to 0.33, the carbon yield was increased from 903% to 4400%. The synthesized MWNTs after purification were dispersed by ball milling method and mixed with waterborne polyurethane to fabricate the electrothermal film. The mass fraction of CNT filler in the cured electrothermal film was controlled at 50%. The coating after drying was ca. 6 μm and the coating’s volume resistivity was 0.053 Ω·cm. The time-dependent temperature curves indicated that the heating rate of the electrothermal film was very fast under different low voltage and the steady-state temperatures were achieved within 100 s. The steady-state temperature reached 47.9 °C, 76.8 °C, and 102.8 °C, respectively at 10 V, 15 V, and 18 V.

Technology Focus: Heavy Oil (April 2020)

Technology Focus Reviewing a myriad of papers presented at different conferences during the past year and attending some of those to hear the oral presentation versions, I can group the current trends in heavy-oil operations and research into two major categories: Process optimization and use of chemicals as additives to steam and water. Here are some highlights from those categories. Several papers focused on purely computational methods—including multi-objective optimization and proxy models—to optimize the steam-assisted gravity drainage (SAGD) method with specific attention on preferential steam allocation. Real-life examples of these applications consist of inflow- and outflow-control devices and steam splitters developed for diverting the steam to preferential zones, thus minimizing the use of steam. As an indirect meth-od to provide supplemental data for the optimized solutions, seismic data were also used. Applications of seismic waves include the depiction of steam-chamber development and monitoring wellbore integrity. Considering that many SAGD operations are reaching maturity, these applications will help maintain the steam/oil ratios at low levels, therefore extending the life of the processes. In another group of studies, chemical additives were tested at the laboratory scale to improve cold (microemulsion formulations) and thermal (to reduce steam/oil ratio) heavy-oil recovery. Examples of newly trialed chemicals include ionic liquids, foam additives, anionic and hydrophobic surfactants, switchable-hydrophilicity tertiary amines, nano-fluids (dispersed SiO2 and ZrO2), ethers, alcohols, and chelating agents as steam additives and microemulsion formulations using SiO2, anionic and nonionic surfactants as well as deep eutectic solvents for cold production. Although most of the listed optimization studies (specific examples reported include the Mackay River, Firebag, and Surmont fields) and chemical tests were done for SAGD conditions (especially at the mature level), these new technologies and applications will be a guidance to the other types of steam operations (cyclic steam injection and steamflooding) using horizontal injectors and producers. In addition to the discussed studies and practices, a plethora of field-scale activities from the Middle East, far east Asia, and the Americas have been reported on consistently. Most of those are early-stage practices or pilots, but a few are related to mature heavy-oil recovery operations. Examples include Kuwait (data collection and development plans for new heavy-oil potentials), Oman (steam management surveillance in the Mukhaizna field), Brazil (development options for the offshore Atalanta field), Venezuela (ongoing operations in the Orinoco belt), Alaska (field-scale polymer-flooding test), China (practices in the Liaohe and Bohai Bay fields), Canada (cold production using methane/ propane mixture and electrical heating pilots in Alberta), Colombia (applications of autonomous inflow-control devices in the Rubiales field), and Indonesia (identification of rod-pump failures in the Duri field). Recommended additional reading at OnePetro: www.onepetro.org. SPE 196072 Laboratory and Field Testing of a Steam-Limiting Flow-Control Device Developed for Thermal Applications by Marty Lastiwka, Suncor Energy, et al. SPE 197321 Surveillance Approach of Steam Management in a Heavy-Oil Reservoir, Oman by Hajer Al Mahruqi, Occidental Petroleum SPE 198697 Effective Reservoir Management With Flow-Control Devices for SAGD Producer Wells in the Mackay River by Giuseppe Rosi, RGL Reservoir Management, et al.

Adsorption of Natural Gas Mixtures of Methane, Ethane, and Propane in Nanoporous Carbon: Fully Atomistic Numerical Studies.

Natural gas (NG) is an interesting primary fuel; its larger-scale use is hindered by the difficulties of storing it under high pressures or low temperatures; a viable alternative is its storage via physisorption in porous materials. Most NG adsorption studies have focused on adsorption of pure methane, its primary component. Here we investigate the influence of heavier alkanes commonly found in NG (propane, ethane) on the adsorption process. We present the results of extensive molecular dynamics simulations of mixtures of methane-propane and methane-ethane at T = 300 and 400 K and P = 0-1500 bar in slit-shaped pores with interlayer spacings H = 8-20 Å. We observed that heavier hydrocarbons adsorb preferentially but remain mobile, which is promising for the intended application. We also solved a common problem with simulations of molecules with high adsorption affinity: the difficulty to determine their partial pressure. We developed an Arrhenius-type relationship allowing the calculation of these partial pressures from relationships between energy distributions of the different molecules in the simulations in conditions where a direct determination of these is impractical or impossible.

THEORETICAL RESEARCH AND PRACTICAL DEVELOPMENT OF THE ARC SPRAYING PROCESS WITH A PULSATING SPRAY AIR STREAM TO IMPROVE THE QUALITY OF COATINGS

The subject of the study is intensive oxidation of metal, sprayed in the process of arc metallization, due to the oxygen in the air, which leads to a significant reduction in the content of alloying elements in the coating and, accordingly, deteriorates the quality of the sprayed layer. Other authors of scientific publications also paid attention to this issue, proposed the use of kerosene, propane and air mixture, inert gases as a transport gas, but these solutions led to a significant increase in the cost of the arc metallization process, and most often had no quantitative calculations of the impact on the quality of coatings or were approximate. The aim of the work was to scientifically substantiate the concept of quality of coatings by reducing the negative impact of air oxygen during arc metallization through the use of a pulsating spray airflow. In order to reduce the oxidative effect of air-spraying jet on the liquid metal of electrodes the method of pulsating air supply to the electrode melting zone by introducing an additional element - pulsator valve in the spray system of electroarc metallizer was proposed. The task of this article is to define and select the design of the device - pulsator valve for creating a controlled pulsating spray flow with certain impulses during arc metallization. The methods of theoretical approach, namely, mathematical analysis, were used to accomplish the task in this paper, as well as practical results – data on the presence of airflow pulsations recorded by an oscilloscope. Thus, the theoretical justification of the pulsator valve application is confirmed by practical results. Based on the presented analysis the results were obtained, which allowed to determine the optimal design, and allows minimizing the impact of the particles (namely oxygen in the air) transporting flow on the material of the electrodes that are sprayed. Conclusions: the use of a pulsating spray airflow during the application of coa tings by arc metallization method will reduce the burnout of alloying elements such as manganese, silicon, increase the carbon content in the applied coating, therefore improving the quality of the restored parts.

Computer modeling system of chemical processes in tubular reactors

A computer modeling system of chemical processes in tubular reactors has been developed. The system helps researchers (technologists, designers) to determine rational modes of operation of tubular reactors, which ensure compliance with the requirements for efficiency indices of chemical processes carried out by various mechanisms. The system includes a module for setting the mechanism of the chemical process, modules for structural synthesis and parameters adjustment of the dynamic mathematical model of the chemical process, a library of finite-difference methods for solving the equation of convective transfer of substance, a module for calculating distributions of concentrations of raw substances and reaction products along the length of the reactor and during time, a module for calculating efficiency indices, a module for generating and storing a modeling report. The information ware of the system includes databases of geometric parameters of tubular reactors and procedural ranges of technological parameters of chemical processes. Databases allow the system to be adjusted according to the tubular reactor brand. The results of the modeling are presented in tables, 2D and 3D graphs of the concentration distributions of raw substances and reaction products. The system has been tested according to the data of thermal decomposition of ethylene, benzene oxidation, pyrolysis of mixture of ethane, butane and propane, production of vinyl acetate. The testing results have confirmed the adequacy of the proposed mathematical description of chemical processes in tubular reactors and the operability of the created software solution.

Dynamics of 2D, V-shaped Bluff-body Stabilized Turbulent Premixed Flames near and Away from Blowoff with Different Gaseous Fuels

ABSTRACT V-shaped premixed flames of propane, methane, and ethylene-air mixtures were stabilized on a triangular-shaped flame holder under three different free stream turbulence levels; 4%, 18%, and 34% rms at a nominal burner exit velocity of 10 m/s. Flames were studied at strongly burning and near blowoff conditions to observe the changes in the overall flame dynamics. Flame behavior at different upstream flow turbulence conditions was visualized by simultaneously capturing the end and side views of flame chemiluminescence using high speed (4 kHz) imaging. A gradual shift from symmetric to asymmetric flame structures was observed with reduction of equivalence ratio approaching blowoff. Particle image velocity measurements confirmed the gradual switch of vortex shedding from symmetric varicose mode to the asymmetric sinuous mode as flame blowoff is approached by reduction of the mixture equivalence ratio. It is found that average flame front position crosses the shear layer from its outer location at strongly burning conditions to within the shear layers bounding the recirculation zone as flame blowoff is approached. Transition of flame behavior from “varicose” to “sinuous” oscillations is documented by way of a symmetry index as a function of equivalence ratio and turbulence intensity for the three fuels studied.

High-Pressure Thermal Conductivity Measurements of a (Methane + Propane) Mixture with a Transient Hot-Wire Apparatus

The transient hot-wire (THW) technique is an absolute technique for measuring the thermal conductivity of fluids. In this work, a THW apparatus was developed for measurements over the temperature range from 193 to 424 K at pressures up to 34 MPa. The apparatus was commissioned with the measurements of pure argon, methane, and propane along several isotherms at pressures up to 33 MPa. The measured values agreed with those calculated with the reference equations within the uncertainty of the equations. Thermal conductivity measurements of a binary mixture (0.9514 methane + 0.0486 propane) were then carried out in the temperature range from 195 to 424 K at pressures up to 31 MPa in a single phase and near the bubble point curve. The relative combined expanded uncertainties (k = 2) for these single-phase and bubble-point mixture measurements were estimated as 2.0 and 5.0%, respectively. The relative deviations of these measured values from those calculated with the extended corresponding state model implement...