Propane Fuels Research Articles

Developing a New Skeletal Mechanism for Propane, Butane, and LPG Fuels

ABSTRACT This study aimed at developing a new skeletal mechanism for LPG fuel capable of predicting combustion in a wide range of engine operating conditions with high fidelity. A novel reduction schematic was developed and applied to the Lawrence Livermore National Laboratory (LLNL) detailed mechanism (980 species, 4972 reactions) concerning NOx and soot formation as well. A two-level reduction method was used in which each level included Direct Relation Graph Error Propagation (DRGEP), DRGEP with isomer lumping, and DRGEP with sensitivity analysis. As a result, the skeletal mechanism was obtained with 88 species and 727 reactions and was successfully verified by comparing the results of the ignition delay/temperature and laminar flame speed/equivalence ratio for the combustion of propane, butane, and fuel mixture (90% propane/10% butane) with the experimental data. The obtained discrepancy of the ignition delay/temperature curves for the fuel mixture was around 5%. Additionally, a zero-dimensional engine calculation was conducted, and the results indicated that the mechanism was successful in predicting the engine combustion pressure with an error of around 5%.

CARBON MONOXIDE POISONING: LITERATURE REVIEW

Carbon monoxide (CO) is known as a colorless, odorless, tasteless, and non irritating gas. CO produced from burning gasoline, wood, charcoal, propane, or other fuels. CO competes with oxygen to bind with Hb, forming COHb and leads to shifting the oxyhemoglobin dissociation curve to the left, reducing oxygen-carrying capacity, and oxygen release into the peripheral tissue. Tissue hypoxia due to CO induces vascular permeability and increased interstitial fluid accumulation with decreased circulating blood volume affecting multiple organs. Three clinical sequences consisted of symptoms consistent with CO poisoning, recent history of CO exposure, and elevated HbCO levels should be present in diagnosing CO poisoning. The current mainstay of CO poisoning treatment is high flow, normobaric (NBO) oxygen therapy administered as soon as possible.

Numerical Analysis of the Structural and Flow Rate Characteristics of the Fuel Injection Pump in a Marine Diesel Engine

A reciprocating fuel pump system was investigated using a modeling approach. The diesel pump system comprises a variable-sized barrel and plunger. This study investigates the effect of diesel, propane, and DME fuels on the plunger barrel’s deformation and flow rate characteristics. It compares the barrel and plunger displacement as a function of working pressure. Based on the multi-field coupling theory, a numerical fluid–solid thermal coupling model was developed to characterize the operational fluctuations in deformation and clearance. Due to the distinct deformation patterns of the two components, the appropriate clearance for the pump’s head and stem must be set independently. In addition, significant AMESim parameters compared and confirmed the discharge flow rates of three distinct fuels. The results show that the maximum displacement for the plunger stem was 0.00266 mm at 7.5 mm from the top of the stem, which was 6.94% lower than the literature result. The DME fuel showed flow stability initially (from 0.0 to 0.4 s) when using a plunger diameter of 23.85 mm. According to the plunger diameters, the marine fuel injection pump’s discharge flow rates increased, minimizing the wearing between the barrel/plunger. The research findings revealed that the suggested structural and flow rate model is recommended for alternative marine fuel applications.

Pr-Doped SrTi0.5Mn0.5O3-δ as an Electrode Material for a Quasi-Symmetrical Solid Oxide Fuel Cell Using Methane and Propane Fuel.

The use of identical electrodes for both the cathode and the anode in a symmetrical solid oxide fuel cell (SSOFC) can simplify the preparation process and increase the durability of the cell, but it is also demanding on the properties of the electrode including stability, electric conductivity, and electrocatalysis. The doping of variable-valence Mn4+/3+2+ on the B site of stable SrTiO3 is explored in this study as both the cathode and the anode for an SSOFC. Though the limit of Mn doping in SrTiO3 is generally low, the additional Pr3+/4+ donor on the Sr site of SrTi0.5Mn0.5O3 was found to enhance the structure stability, electric conductivity, and electrocatalysis. The cell with Pr0.5Sr0.5Ti0.5Mn0.5O3 electrodes excels under H2, propane, or CH4/H2 fuel, providing the cocatalyst was infiltrated on the anode side. The polarization resistance value of Pr0.5Sr0.5Ti0.5Mn0.5O3 was 0.27 Ω·cm2 as the cathode and 0.33 Ω·cm2 for the SSOFC using H2 fuel. The performance under CH4/H2 fuel can be boosted to above 0.9 W cm-2 if Ni/ceria was loaded onto the anode to enhance the methane reforming. This work contributes to a perovskite anode with high Mn doping in SrTiO3 for application in SSOFC for natural gas with renewable H2 injection.

Characterization of Propane Fueled Flames: A Significant Source of Brown Carbon

In this study, we developed a framework for interpreting the in situ morphological properties of black carbon (BC, also referred to as “soot” due to combustion relevance) mixed with primary organic aerosol. Integration of the experiment considering primary organic aerosol (POA) evaporation from the soot particles was examined using a Differential mass–mobility analyzer (DMA) and showed the untold story of the mixing of BC and POA. We also hypothesize that morphological transformation of soots and determined such as (i) the evaporation of externally and internally mixed POA led to a decline in the particle number and size of monodisperse aerosol; (ii) presence of externally mixed BC was interpreted from the occurrence of two peaks of soot upon heating; (iii) heat-induced collapse of the BC core possibly resulted from the evaporation of material from the voids and effect of heat; (iv) volume equivalent to changes in the mobility diameter represented evaporation of POA from the surface and collapse upon heating. POA constituted a high fraction (20–40% by mass) of aerosol mass from these flames and was predominantly (i.e., 92–97% by mass) internally mixed with BC. POA was found to be highly light absorptive, i.e., an Ångström absorption exponent (AAE) value of (in general) >1.5 was estimated for BC + POA at 405/781 nm wavelengths. Interestingly, a much more highly absorptive POA [mass absorption cross-section (MAC)-5 m2 g−1] at 405 nm was discovered under a specific flame setting, which was comparable to MACs of BC particles (8–9 m2 g−1).

The decreasing effect of ammonia enrichment on the combustion emission of hydrogen, methane, and propane fuels

In the present study, non-premixed combustion and NOx emission of H2, NH3, C3H8, and CH4 fuels have been studied in a combustion test unit under lean mixture conditions (λ = 4) at 8.6 kW thermal capacity. Furthermore, the combustion and NOx emission of the H2, C3H8, and CH4 fuels have been investigated for various NH3 enrichment ratios (5, 10, 20, and 50%) and excess air coefficients (λ = 1.1, 2, 3, and 4) at the same thermal capacity. The obtained results have been compared for each fuel. Numerical simulation results show that H2 emits intense energy through the reaction zone despite the lowest fuel consumption in mass, among others, due to its high calorific value. Therefore, it has a higher flame temperature than others. At the same time, C3H8 has the lowest flame temperature. Besides, NH3 has the shortest flame length among others, while C3H8 has the most extended flame form. The highest level of NOx is released from the NH3 flame in the combustion chamber, while the lowest NOx is released from the CH4. However, the lowest NOx emission at the combustion chamber exit is obtained in NH3 combustion, while the highest NOx emission is obtained with H2 combustion. It results from the shortest flame length of NH3, short residence time, and backward NOx reduction to N2 for NH3. As for H2, high flame temperature and relatively long flame, and high residence time of the products trigger NOx formation and keep the NOx level high. On the other hand, excess air coefficient from 1.1 to 2 increases NOx for H2, CH4, and NH3 due to their large flame diameters, unlike propane. Then, NOx emission levels decrease sharply as the excess air coefficient increases to 4 for each fuel. NH3 fuel also emits minimum NOx in other excess air coefficients at the exit, while H2 emits too much emission. With NH3 enrichment, the NOx emissions of H2, CH4, and C3H8 fuels at the combustion chamber exit decrease gradually almost every excess air coefficient apart from λ = 1.1. As a general conclusion, like renewable fuels, H2 appears to be a source of pollution in terms of NOx emissions in combustion applications. In contrast, NH3 appears to be a relatively modest fuel with a low NOx level. In addition, the high amount of NOx emission released from H2 and other fuels during the combustion can be remarkably reduced by NH3 enrichment with an excess air combustion.

Design and analysis of six-stroke engine by using the alternative fuel to enhance thermal efficiency

The Six-Stroke cycle consists of a standard four-stroke Otto Cycle followed by a heat recovering and expansion cycle. Therefore, this processing power uses heat and increases the engine's overall efficiency. To recover the waste heat, various methods are being adopted, and significant modifications to the conventional internal combustion engine must be done. In this paper, the improvement of the Six-Stroke engine performance is observed by varying the working fuel used in the Six-Stroke. The limitation of the Six-Stroke is described, and an idea for the alternative six-stroke cycle is to increase the amount of heat recovered. The performance of the six-stroke engine is observed with Petrol, Methanol, Ethanol, and Propane fuels with required thermodynamic analysis. To know the amount of percentage of waste energy, additional strokes are recorded and thermal efficiency calculated. For the Six-stroke, the general design of the piston is noticed and simulated. It is concluded that Methanol and Ethanol had the most significant feature for the Six-Stroke engine.

A New Design Using a Metal Wire Brush as the Current Collector of Micro-Tubular SOFCs

In this study, a novel current collecting method was designed and demonstrated by inserting a metal wire brush into the anode supported micro-tubular SOFC. The new design enables a close and stable contact between the wire and the inner wall of the anode which leads to a fine performance of the SOFC. Different kinds of metal wires were applied, where the copper wire brush (CWB) shows a better performance than the stainless steel wire brush (SSWB). At a temperature of 650℃ and a fuel feed of hydrogen, the SOFC using CWB can achieve a maximum power density of 278mW/cm2 and an ohmic resistance of 0.75 Ω∙cm2, which are both better than that of SSWB (226mW/cm2 and 0.89 Ω∙cm2). While the brush size has been approved to have little effect on the ohmic resistance and the electrochemical performance. The potential of the metal wire brush as a support for internal reforming catalysts is further verified in experiments. The metal wire brushes loaded with Pt and Ni catalysts can realize effective reforming of hydrocarbon fuels, which makes the new design potential to use methane, propane, butane and other fuels for power generation. Key words: Micro-tubular SOFC; Current collecting; Metal wire brush; Internal reforming

Comparing the Potentiality of Propane, Propanol and Octane Fuel Using in SI Engine Based on Energy-Exergy Analysis

From the beginning of IC engine era, it is trying to improve the performance and efficiency of internal combustion engine. In this study, numerically analysis on combustion of Propane, Propanol and Octane in SI engine have been done thoroughly and presented to assess the potentiality and highlighted the comparison. For this analysis thermodynamic engine cycle model is developed for numerical analysis. Mathematical models considering fundamental equation and empirical relation are implemented in a single cylinder 4 stroke spark ignition engine (system) with the help of FORTRAN 95 to find out heat losses, friction losses, output parameter etc. Single cylinder four-stroke spark-ignition (SI) engine is considered as system. In this study, different working parameters like 8 and 12 compression ratios with three different rpm 2000, 4000 & 6000 are considered for simulation. This study shows the different comparisons of energy-exergy content (%), as example of exhaust gas 35.08 & 17.82, 37.02 & 19.22, 37.79 & 19.79 for Octane (at compression ratio 8 and 2000, 4000, 6000 rpm) etc., which explains the potentiality content and the potentiality losses in different process like combustion, mixing of gases etc. It also shows for the fuel propane and propanol in similar way with changing different operating conditions. Maximum inside cylinder temperature, 1st law and 2nd law efficiencies were determined for the fuels with respect to different compression ratio and engine speed.

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.

The critical lower radius limit approach for laminar flame speed measurement from spherically expanding stretched flames

Spherically expanding flames are severely affected by flame stretch in the early stage of combustion and therefore stretch models are of great importance in determining the uncertainty of experimental laminar flame speeds (SL) and burned gas Markstein lengths (Lb). In order to prevent the existing large scatter in experimental data of these two fundamental flame parameters, the effect of the lower radius limit for the flame speed calculation on extrapolation results of the stretch models was investigated through spherically expanding flames under constant pressure. Methane, hydrogen, propane, and iso-octane fuels were tested to account for both hydrocarbon and non-hydrocarbon fuels with different evolutions in the burned gas Markstein length when equivalence ratio is increased. Results show that there is a critical lower radius limit (RL,critical), where all laminar flame speed and burned gas Markstein length values obtained by the extrapolation of the stretch models converge to the same laminar flame speed and burned gas Markstein length. The value of the critical lower radius limit strongly depends on the burned gas Markstein number (Mab) and this dependency can be shown with |Mab|=0.8424*RL,critical for fuel/oxidizer mixtures with −0.48 mm ≤ Lb ≤ 1.23 mm (or, −0.62 ≤ Mab ≤ 2.60). Finally, laminar flame speeds and burned gas Markstein lengths of methane, hydrogen, propane, and iso-octane flames that were corrected according to the critical lower radius limit approach proposed in the present study were compared to previously published experimental results.

Investigation of pressure and the Lewis number effects in the context of algebraic flame surface density closure for LES of premixed turbulent combustion

Large scale industrial combustion devices, for example, internal combustion engines, gas turbine combustors, etc., operate under high-pressure conditions and utilize a variety of fuels. Unfortunately, the majority of the current numerical combustion modelling approaches are not fully validated for high-pressure and the non-unity Lewis number ( $$\hbox {Le} =$$ thermal diffusivity/mass diffusivity) effects in premixed turbulent combustion. In any case, a numerical model needs to be checked for the effects of these parameters to guarantee generality of the model. In the present study, these two critical features of the models are numerically explored utilizing fundamental elements of several algebraic flame surface density reaction rate closure models accessible in the open literature. The Lewis number impact is likewise examined utilizing LES of recently published subgrid scale fractal flame surface density model, which indicated acceptable results for high and low-pressure methane fuelled applications. The computed numerical results are compared with an extensive experimental dataset for lean methane and propane fuels featuring various flow and turbulence conditions at operating pressures in the range of 1–10 bar. The quantitative results from most of the selected models do not show the experimentally observed trends at high-pressures and for non-unity Le number fuels. Modifications to the models are incorporated to reflect effects of these two important parameters utilizing a broad parametric investigation resulting in a satisfactory agreement with the experimental data.

Exergy and Energy Analysis of Solid Oxide Fuel Cell Fuelled Using Methanol Propane, and Butane

Exergy and Energy analysis used the principle of conservation of mass and energy, in connection with thermodynamics law in designing and analysing of thermal system This Paper focus on Energy and Exergy analysis of Solid Oxide Fuel Cell (SOFC) system by computer simulation. A comprehensive effect of Energy and Exergy analysis on SOFC using Methanol, Propane, and Butane fuel system with the aid of Thermolib simulation toolbox was investigated. From the configurations simulated for the three different fuel sources, the data produced were used for thermodynamic analysis. The result obtained showed that Butane configuration has the highest energy efficiency of 50.3% .while Methanol and Propane system has an energy efficiency of 46.5% and 47.7% respectively. The total energy produced by Methanol, Propane and Butane Fuel System are 273.66 KW, 234.67 and 263.92 kW respectively. While that required are 69.45 KW, 0.062 KW and 4.972 KW respectively. This shows that the highest energy requiring and producing system is the Methanol Fuelled system. The principle of energy conservation was met in all configurations. The Exergy analysis indicated that around equipment such as Reactor, lambda burner and SOFC stack there is a change between the inlet and outlet chemical Exergy. However the chemical Exergy for Pumps, Heat exchangers, compressor and Mixer remains the same because no chemical reaction occurs in them. In addition, equipment such as pump and compressor gives higher Exergetic efficiency than others. In terms of overall loss work, Methanol, Propane, and Butane system are 422.2 KW, 247.7KW, 195.7 KW respectively. The Overall System Exergetic efficiency of the three fuel systems are 44.2%, 49.3%, and 46.7% respectively. This shows that Propane system has the highest Exergetic efficiency and least irreversibility. While Methanol fuel system has the lowest Exergetic efficiency and most irreversibility. Exergy and energy efficiency favours the choice of propane fuel system. This is because Propane is the most Exergy efficiency system.

Maximum thermodynamic electrical efficiency of fuel cell system and results for hydrogen, methane, and propane fuels

The maximum electrical efficiency of fuel cell system, ηemax, is important for the understanding and development of the fuel cell technology. Attempt is made to build a theory for ηemax by considering the energy requirement of heating the fuel and air streams to the fuel cell operating temperature T. A general thermodynamic analysis is performed and the energy balances for the overall operating processes of a fuel cell system are established. Explicit expressions for the determination of ηemax are deduced. Unlike the Carnot efficiency, ηemax is found to be fuel specific. Except for hydrogen fuel, chemical equilibrium calculations are necessary to compute ηemax. Analytical solutions for the chemical equilibrium of alkane fuels are presented. The theoretical model is used to analyze the effects of T and the steam contents of CH4, C3H8, and H2 on ηemax for systems with various degrees of waste heat recovery. Contrary to the common perception concerning methane and propane fuels, ηemax decreases substantially with the increase of T. Moreover, ηemax of hydrogen fuel can be higher than that of methane and propane fuels for a system with a medium level of waste heat recovery and operated at 700 ℃≤T≤900 ℃.

Effect of pressure on the transfer functions of premixed methane and propane swirl flames

This paper reports on the effect of pressure on the response of methane–air and propane–air swirl flames to acoustic excitation of the flow. These effects are analyzed on the basis of the flame transfer function (FTF) formalism, experimentally determined from velocity and global OH* chemiluminescence measurements at pressures up to 5 bar. In parallel, phase-locked images of OH* chemiluminescence are collected and analyzed in order to determine the associated flame dynamics. Flame transfer functions and visual flame dynamics at atmospheric pressure are found to be similar to previous studies with comparable experimental conditions. Regardless of pressure, propane flames exhibit a much larger FTF gain than methane flames. For both fuels, the effect of pressure primarily is to modify the gain response at the local maximum of the FTF, at a Strouhal number around 0.5 (176 Hz). For methane flames, this gain maximum increases monotonically with pressure, while for propane flames it increases from 1 to 3 bar and decreases from 3 to 5 bar. At this frequency and regardless of pressure, the flame motion is driven by flame vortex roll-up, suggesting that pressure affects the FTF by modifying the interaction of the flame with the vortex detached from the injector rim during a forcing period. The complex heat transfer, fluid dynamics, and combustion coupling in this configuration does not allow keeping the vortex properties constant when pressure is increased. However, the different trends of the FTF gain observed for methane and propane fuels with increasing pressure imply that intrinsic flame properties and fuel chemistry, and their variation with pressure, play an important role in controlling the response of these flames to acoustic forcing.

Generalization of the radiative fraction correlation for hydrogen and hydrocarbon jet fires in subsonic and chocked flow regimes

The radiative fraction is one key parameter to characterize the jet flame combustion dynamics and to calculate the thermal radiant heat emitted from jet fire. A theoretical analysis is conducted to clarify the key parameters that dominate the radiative fraction of jet fires, with discussion of the limitation of previous radiative fraction correlations. A completely new dimensionless group, consisting of the mass fraction of fuel at stoichiometric conditions, the density ratio of fuel gas to ambient air and the flame Froude number, is proposed to correlate the radiative fraction of jet fires. The current up-to-date experimental data are used to build the radiative fraction correlation that covers orifice exit diameters from one to hundreds of millimeter, hydrogen, methane and propane fuels, vertical and horizontal jets, buoyance- and momentum-controlled releases, subsonic, sonic and supersonic jets. It is found that the source Froude number can fit the radiative fraction of a particular fuel jet fire. However, the new dimensionless group can correlate the radiative fractions of fuel-different jet fires. The predictive capability of the new correlation exceeds that of previously published work based on the source Froude number only or the global residence time with/without correction factors.

Self-Regenerating Co–Fe Nanoparticles on Perovskite Oxides as a Hydrocarbon Fuel Oxidation Catalyst in Solid Oxide Fuel Cells

Metal nanoparticles exsolved from perovskite oxides have created great interest as anode materials in solid oxide fuel cells (SOFC) due to their high catalytic activity and regenerative capability. However, the self-regeneration process generally occurs at relatively high temperatures (>800 °C), which might limit their practical application. Here, we present a perovskite anode material, La0.3Sr0.7Cr0.3Fe0.6Co0.1O3−δ, which allows Co–Fe nanoparticles exsolved on the oxide surface at intermediate operation temperatures (700 °C). The phase stability of the perovskite oxide and the reversibility of the exsolved alloy were carefully examined by the phase characterization and the nanoparticle morphology observation during the redox process. The electrochemical performance was evaluated by an electrolyte-supported single cell with hydrogen and propane fuels. The Co–Fe nanocatalysts enhance the maximum power density of the La0.3Sr0.7Cr0.3Fe0.6Co0.1O3−δ–Gd0.2Ce0.8O1.9 (GDC) composite anode more than 75% in compari...

Mobile Robots Enhanced by microtubular Solid Oxide Fuel Cells (mSOFCs)

Mobile robots are limited by their battery energy storage. Solid Oxide Fuel Cells running on propane or other liquid fuels can enhance the battery robot range by an order of magnitude while allowing rapid refilling. The need is to improve the system power to weight (P/W) ratio. Moving to smaller diameter microtubular SOFCs (mSOFCs) is beneficial in raising the stack P/W, but the system components including thermal insulation, cathode air heater and reformer are also important. This paper describes experiments on a 100W mSOFC system to show that 100Wkg-1 power density can be obtained by improving system components and integration. This system could power a small fixed wing Unmanned Air Vehicle (UAV) but needs to be improved by a further factor 5 to fly a helicopter.

Techno-economic analysis of hybrid PV/T systems for process heat using electricity to subsidize the cost of heat

Process heat applications make up a large potential market for renewable energy. Concentrated solar thermal (CST) systems are capable of reaching temperatures necessary for a wide variety of industrial and commercial applications but are often overlooked due to the difficulty of competing with natural gas. Novel hybrid photovoltaic/thermal systems (PV/T) are capable of simultaneously generating electricity and heat. The electricity produced is of higher value and offsets the lifetime cost of the system by producing a cost savings to the facility, ultimately making solar heat competitive with natural gas, propane, coal, and other fuels. An economic model that utilizes the electricity savings as part of the cash flow within the levelized cost of energy equation is presented here. We further determine the sensitivity of PV/T system costs to technical, financial, and geographical parameters. A dish concentrator PV/T (CPV/T) system with a transmissive CPV array is used as a reference system for sensitivity analysis. Through design choices informed by this new modeling approach, the levelized cost of heat (LCOH) is shown to be competitive with natural gas in up to 6 states within the United States and can be reduced to a minimum of −1.4¢/kWhth in Hawaii by factoring in the electricity savings from additional energy generated by the transmissive CPV module. Competitiveness in select global regions is also considered. Further examination of several other geometries of PV/T systems with this model, for an installation in California, shows that flat plate collectors with waste heat recovery result in the lowest LCOH of 1.23¢/kWhth.

Large scale detonation testing: New findings in the prediction of DDTs at large scales

A large vapor cloud explosion (VCE) followed by a fire is one of the most dangerous and high-consequence events that can occur at petrochemical facilities. As the size and complexity of facilities increase, designs must consider the potential adverse effects associated with vapor cloud explosions in large congested areas and understand the potential for more devastating deflagration-to-detonation transitions (DDTs) on these facilities. While the likelihood of DDTs is lower than deflagrations, they have been identified in some of the most recent large-scale explosion incidents including: 2005 Buncefield explosion, 2009 San Juan explosion, and 2009 Jaipur event. The consequences of DDTs can be orders of magnitude larger than deflagration because they have the ability to self-propagate outside the region of high congestion/confinement. Hence, it is critical to understand how a facility's geometry or equipment layout can affect explosion consequences and assist in their mitigation and/or prevention.Due to the inability to predict such devastating phenomena on the large scale, owners and designers cannot evaluate installations for risk of DDTs and provide “inherently safer” layout or mitigation measures to significantly reduce or eliminate such hazards. However, there is a lack of data at the large scale to validate the necessary design tools used to predict the risk of DDT. One of the main goals of this research project is to provide large scale DDT explosion data and validate the tools necessary to predict vapor cloud explosions in early design phase.This paper will present the results of large scale testing being conducted in a newly developed test rig of 50,000 ft3 (1500 m3) gross volume under award Subcontract 12121-6403-01 provided by the Research Partnership to Secure Energy for America (RPSEA). These tests involve evaluation of deflagrations and DDTs involving stoichiometric, lean and rich mixtures, with propane and methane fuels. The effectiveness of mitigation techniques such as solid inhibitors or deluge is evaluated for preventing DDTs.