Article pubs.acs.org/IECR
Analysis of Gas Explosion Consequence Models for the Explosion Risk Control in the New Gas Energy Filling Stations Seungkyu Dan,†,§ Dong Ju Moon,∥ En Sup Yoon,†,§ and Dongil Shin*,‡ †
School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, Korea Department of Chemical Engineering, Myongji University, Yongin, Gyeonggido 449-728, Korea § Automation and Systems Research Institute, Seoul National University, Seoul 151-742, Korea ∥ Clean Energy Research Center, Korea Institute of Science Technology, Seoul 136-791, Korea ‡
ABSTRACT: New sorts of energy are emerging as alternative clean fuel for transportation, power generation, and household. Using the DME−LPG mixture or HCNG is being considered and investigated as an improved option for the satisfaction of regulations over current policy of using LPG or CNG. In this research, we compare the safety of mixture fuels and existing fuels in the perspective of explosion risk that would be the biggest concern in the operation of new-energy stations. The explosion risk is analyzed and compared by using three different representative models: empirical, phenomenological, and CFD-based models, ordered in increased model complexity and computational and modeling efforts. Maximum overpressures of explosion of mixture and existing fuels respectively show similar results, in all three models, and no additional risk is expected in the modified use of current refueling facilities. CFD-based explosion simulation is determined to be used in deciding the exact overpressure distribution and optimal installation of prevention equipment, and a guideline is suggested. The final results are being adopted as part of new safety regulations for existing mixture stations and will be adapted at the new facilities in Korea. As a simple way to enable legacy models to estimate the dynamic consequence by explosion, a modified code that combines a gas dynamics solver with an empirical model is also suggested.
1. INTRODUCTION Since the environmental pollution problems and climate issues related to ever-increasing energy use have been emerging all over the world, developing efficient renewable and/or alternative clean energy sources are considered as top-priority research agenda of the world.1 Among those efforts, DME (dimethyl ether) has emerged as an attractive, promising, alternative clean fuel for transportation, power generation, and household. The Korean government is promoting commercial introduction of this new clean energy DME, covering from DME synthesis from feedstock, such as natural gas, through utilization of DME as fuel by end users. Using DME as fuel for car satisfies regulations of environmental pollution, since a car run by DME discharges less NOx or unburned hydrocarbon than using gasoline or diesel. However, there are difficulties and concerns making dedicated facilities and DME vehicles. Rather than using only DME, as an intermediate step for easier adoption, using a DME and LPG mixture is considered as a practical way before expanding and improving the DME facilities and vehicles. Because material characteristics of DME are similar to LPG, it is possible to use a DME−LPG mixture as a substitutive fuel at existing charging stations, without seriously modifying the current facilities.2 CNG is also used as an alternative fuel for buses in Korea, but it would not be sufficient for the satisfaction of enhancing regulations. In a few years, it is going to be used with hydrogen to alleviate the air pollution after combustion. Figure 1 shows the emission levels after combustion of CNG and HCNG, respectively.3 Using the new mixtures still deals with flammable gas, and therefore, when dealing with new mixtures at the conventional © 2013 American Chemical Society
Figure 1. Comparison of the emission levels after combustion (adapted from governmental data3).
filling stations, safety management does not become an automatically solved issue. Since the severe accident occurred at Bucheon LPG filling station, regulations of operation, expansion, and construction of LPG stations have been restricted and heavily controlled by the Korean government.4 Thus, converting and continuously operating conventional filling stations as new energy stations must be thoroughly analyzed and studied to get the acceptance and approval by local communities and government authorities. Special Issue: PSE-2012 Received: Revised: Accepted: Published: 7265
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essential physics of explosions. They are made by simplification of the geometry, and they consider a simplified condition for the simulation: wind, temperature, atmospheric pressure, etc. PHAST,9 which has been selected as the phenomenological model for our research, is a general tool for consequence analysis, examining the progress of a chemical process incident from initial release through formation of a cloud or pool to final dispersion, and calculating concentration, fire radiation, toxicity, and explosion overpressure. PHAST is a comprehensive hazard analysis package, applicable to all stages of design and operation across a range of process and chemical industry sectors. The VCE in the PHAST calculates the overpressure P0 based on the TNT equivalency model, as below:9
To improve the safe use of gas, this research compares the safety of mixture fuels against LPG or CNG in the perspective of explosion risk, which could be the biggest concern when dealing with flammable gases. The prediction of gas explosion overpressures and upgrading the overall design, including the introduction of prevention facilities, are becoming more important than ever when considering safety assessments of plant design and layout. The development strategy for improving gas explosion models is also highly desirable, since using gas mixtures as energy sources is expected to grow in the near future.5
2. BACKGROUND 2.1. Comparison of Explosion Simulation Models. Accurate assessments about possible accidents are required to reduce the loss caused by overpressure resulting from gas explosion. There are many models ranging from calculations using a simple expression to complex numerical formulations based on CFD. First of all, selecting and using appropriate models for the problem are important, as the information requirements and efforts to run the models increase with the demand of accuracy. The estimations of the explosion risk have been conducted by following three approaches: Empirical models are based on correlations obtained from analysis of experimental data (i.e., the TNT equivalency model, the TNO multi-energy model, etc.); phenomenological models are simplified physical models, which simply use computer software based on empirical correlations, which seek to represent only the essential physics of explosions (i.e., PHAST, SuperChem, etc.); and using computer simulation programs based on computational fluid dynamics (CFD) models (i.e., FLACS, EXSIM, etc.) find numerical solutions to the partial differential equations governing the explosion process.6,7 2.1.1. Empirical Model. Empirical models are based on correlations obtained from analysis of experimental data. Among these models, the TNT equivalency model is a representative empirical model and very simple and easy to use. The TNT equivalency model is based on the assumption that gas explosion is similar to an explosive of high efficiency. There are many differences between gas explosion and solid explosion, but using the utility factor helps correct the gap. Equations 1 and 2 below calculate overpressure from the explosion effect of TNT. The calculation of scaled distance is necessary to obtain the overpressure out of the calculation from eq 1: W=
ZG =
ηMEc E TNT
log P0 = 0.2518(log ZG)2 − 2.0225(log ZG) + 5.8095 (3)
2.1.3. Simulation Based on the CFD Model. Computer simulation programs based on CFD models solve partial differential equations, based on Navier−Stokes equations that govern the fluid flow, to calculate the phenomena controlling the explosion process. CFD simulations can offer insight into the flow behavior in situations where it is impractical or impossible to carry out experiments. Its use is being widely accepted for risk analysis of explosion or dispersion.10 The equations in each model are based on the Navier−Stokes equation, but there are some different ways for calculating results. EXSIM uses the eddy dissipation combustion model for calculating the turbulent combustion rate. In FLACS (FLame ACceleration Simulator), the k−ε turbulence model and β flame model are used. AutoReaGas uses the eddy break-up and dissipation model. The k−ε turbulence model and Reynolds stress transport equation are used in CFX-4.6,11 Because the model assumptions and detailed implementations are different in each model, the results after simulation of the same scenario may be different. Thus, the selection and use considering the strong and weak points of each implementation would be important to get the desired and accurate results.12,13 CFD-based complicated models are widely acknowledged for showing the necessary accuracy required for the adoption of simulation results for detailed safety reviews and corresponding upgraded design of process plants. In this research, FLACS is utilized as a representative tool for dispersion and explosion simulations based on CFD. Its main models consist of equations for reaction rate, combustion (laminar burning velocity), flame propagation, and burning velocity.14 2.2. Overpressure Simulation for Explosion of LPG, DME−LPG, CNG, and HCNG. For the comparison of the aforementioned three models and the proper risk control, prediction and estimation are carried out for exact damages of LPG and DME−LPG refueling facilities’ explosion, by running the simulation for the 3D structure of a refilling station. Even though some experimental studies have been conducted and available for the explosion characteristics of DME, we need to simulate for the given 3D structure of the recharging station to get the precise view of the explosion consequence. However, unlike usual process simulators, there is no physical property built in for DME in FLACS, so using FLACS directly for the DME−LPG case has some difficulties, without further experimental verification for the reduction of the uncertainty in the results accuracy.15,16 Properties of methane, the main component material of CNG, and hydrogen have been input as flammable gas to FLACS, to run the simulations for LPG and HCNG cases.
(1)
RG W 1/3
(2)
where W is the equivalent mass of TNT (kg or lb), η is the empirical explosion efficiency (unitless), M is the mass of hydrocarbon (kg or lb), Ec is the heat of combustion of flammable gas (kJ/kg or Btu/lb), ETNT is the heat of combustion of TNT (4437−4765 kJ/kg or 1943−2049 Btu/lb), RG is the real distance (m), and ZG is the scaled distance.8 After calculations of the above expressions, we estimate the overpressure results by using the overpressure versus scaled distance chart like Brasie and Simpson.22 2.1.2. Phenomenological Model. Phenomenological models are simplified physical models, which seek to represent only the 7266
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2.3. Overpressure Propagation Code for Legacy Explosion Models. Some phenomenological model shows incompleteness performance on explosion simulation and its reliability is very low to adjust against the real situation. As an alternative for the CFD-based simulation, a public-domain gas dynamics solver like Gas Dynamics Toolbox17 (an implementation of a Godunov-type solver for gas dynamics equations in Matlab) might be run in an integrated way to calculate peak pressure and propagation of the peak pressure from ignition to the surrounding. Our version of the code first calculates the peak pressure by using the TNT equivalency model as the empirical model, and then the propagation of the peak pressure is calculated by the toolbox.
In the case of CNG or HCNG, the pressurized tank under the ground is selected to estimate the results of overpressure. Because the state of stored fuel is still gas, the possible explosion by flammable gas is vapor cloud explosion, and BLEVE does not occur. Instead of BLEVE, it is possible that the tank is ruptured physically (as shown in Figure 2).19 Nevertheless, explosion by only hydrogen may not occur because of dispersion to the air, and mixture of CNG and hydrogen should be included in the assessment of explosion.20 3.2. Construction of the 3D Geometry. The schematics of the DME−LPG station we have studied is shown in Figure 3, as well as its 3D geometry modeled in FLACS. Because the DME− LPG station is not operating yet, the test bed was created by simplifying the Bucheon LPG refueling system in Korea, which was well studied after the severe accident of gas explosion that occurred in 1998. There are three tanks in the refueling facility, and one of the tanks stores DME−LPG mixtures (see Figure 3).
3. EXPLOSION SCENARIO AND PROCESS SETUP 3.1. Representative Accident Scenarios. DME−LPG refilling stations, still being developed, may begin the operation by setting one of the two types of tanks. One type is adding a new tank that can store 5 ton of DME−LPG mixture gas, to be located nearby an existing LPG tank. Another way is using an existing tank that can store 40 ton of DME−LPG. The pressurizing of tanks is classified into three types depending on the status: pressurized on the ground, refrigeration on the ground, or pressurized under the ground. The pressurized tank on the ground was selected as the representative case in this research.18 Once a release occurs caused by an accident, flammable gases are shaped around the refueling facility. After the release, fire or explosion could happen if an ignition is followed by that accident. Between fire and explosion, we focused on the overpressure hazard out of the explosion.
Figure 4. New energy refueling facility modeled in FLACS.
Figure 2. Simulation of physical rupture of tanks, none resulting in BLEVE.
Figure 5. Additional setup for the simulation of explosion in FLACS.
Figure 3. Schematic diagram of the Bucheon LPG refueling system (adapted from Park et al.4). 7267
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3.5 ton of TNT. Calculated overpressure within a range of 30 m from the ignition is higher than 1 bar. And the value of the place located 0.5 km from the ignition is almost 0.001 bar, so it seems to be no harm after that. Figure 7 is the overpressure plot relative to distance, obtained by the TNT equivalency model. 4.2. Phenomenological Model (PHAST). As the case of the phenomenological model, the results of PHAST were obtained. It is quite easy to make the simulation for DME explosion in PHAST, compared to the case of using FLACS. Comparisons of overpressure between LPG and DME−LPG mixtures were done, the same as the case of the TNT equivalency model. Figures 8 and 9 show overpressure relative to distance, in the case of VCE and BLEVE explosions of LPG and DME−LPG mixtures, respectively. In Figures 8 and 9, we can see that overpressure of explosion of LPG and DME−LPG is similar to each other, as we already noticed in the result from the TNT equivalency model. Thus, it seems like there is no additional magnitude of risk in using DME−LPG at the existing refueling facilities. The results show that overpressure is 18 bar near the ignition and 4 bar near 10 m away from the ignition. It shows a little different value from the TNT equivalency model, but the overall shapes of the decreasing graph are similar to each other. In Figure 10, we can see that the overpressures of explosion of CNG and HCNG are similar to each other. The results show that overpressure is 1 bar near the ignition and 0.87 bar near 50 m away from the ignition. 4.3. CFD-Based Model (FLACS). As mentioned in the previous sections, there is no physical property estimation model built in for new energy materials, and DME simulations need more thorough validation with additions of experimental data on the explosion characteristics of DME.21 Thus, DME and DME− LPG simulations could not be finished with confidence, and this section gives results only on LPG, CNG, and HCNG cases. Figure 11 shows a distribution of peak overpressure after ignition. The highest overpressure occurred near the ignition point. Figure 12 shows a change of overpressure of LPG with time. The time of the explosion was about 0.2 s after the start of the simulation, and the highest overpressure of LPG in the facilities is 0.026 bar. Figure 13 shows the distribution and change of overpressure with time. The value of the peak overpressure of CNG is 0.019 bar at 17 s after the ignition, and the value of HCNG is 0.016 bar at 0.34 s after the ignition in the facility. The discrepancy of explosion time between CNG and HCNG is confirmed because of the effects of the hydrogen which participated in the explosion. As noticed in the previous sections, there are advantages of 3D explosion simulation based on CFD. First, it can simulate for a plant layout similar to the real construction of the facilities. Second, it can confirm the results that closely resemble the real dynamic situation of accidents. Third, it informs the user of the results for the precise points where we want to know the details. Results of simulations by the three models were summarized as Tables 5 and 6. In the case of LPG and DME−LPG, compared against the TNT equivalency model, PHAST results show a little lower values near the ignition but a little bigger values far from the ignition. The FLACS was simulated only for VCE, and comparison of its BLEVE results is still being prepared. In the results of CNG and HCNG, although the results of simulation about the HCNG mixture are a little higher than the CNG, its values are almost the same. 4.4. Overpressure Propagation Code for Legacy Explosion Models. The results from this code are as follows. Figure 14 shows the profiles of propagating overpressure with time,
In the case of the CNG station, the 3D structure of the simulation was adapted from currently operating CNG stations in Korea, with addition of tanks for H2 and HCNG. Pressurized gas tanks are laid under the ground, and HCNG is stored in the mixture tank for discharging from one line (see Figure 4). 3.3. Additional Setup for the Simulation of Explosion. For further risk analysis from the explosion simulation, we have to select important variables for which the results would be collected (e.g., max pressure, overpressure at certain locations, etc.). We also set monitor points in FLACS, which are located where we want to confirm and save the results. Moreover, as shown in Figure 5, it is necessary to select gas composition and size by volume, location of the ignition, etc.
4. RESULTS AND DISCUSSION 4.1. Empirical Model (TNT Equivalency Model). The results by the TNT equivalency model are not exact values because the TNT equivalency model is a calculation of an experimental equation, but it easily gives approximate values of the overpressure. The results calculated by eqs 1 and 2 show that the explosion effect of 5 ton of LPG is similar to 1 ton of TNT and DME−LPG is similar to 0.926 ton of TNT. Predicted overpressures from the calculated scaled-distance are shown as Tables 1 and 2. Overpressure within a range of 20 m from the Table 1. Overpressure Relative to Distance for LPG Explosion by TNT Equivalency Modela distance
scaleddistance
overpressure
distance
scaleddistance
overpressure
1 10 20 30 40 50 100
0.1 1 2 3 4 5 10
more than 10 5.8 1.2 0.52 0.31 0.21 0.08
200 300 500 1000 2000 3000 5000
20 30 50 100 200 300 500
0.036 0.022 0.013 0.0055 0.0027 0.0018 0.001
a
Distance, m; overpressure, bar.
Table 2. Overpressure Relative to Distance for DME−LPG (2:8) Explosion by TNT Equivalency Modela distance
scaleddistance
overpressure
distance
scaleddistance
overpressure
1 10 20 30 40 50 100
0.10 1.03 2.05 3.08 4.10 5.13 10.26
more than 10 5.3 1.05 0.48 0.3 0.205 0.078
200 300 500 1000 2000 3000 4000
20.52 30.78 51.3 102.60 205.19 307.79 410.38
0.032 0.02 0.011 0.0051 0.0025 0.0017 0.0011
a
Distance, m; overpressure, bar.
ignition is higher than 1 bar. As the distance is away more and more, it becomes decreasing rapidly. The value of the place located 0.5 km from the ignition is lower than 0.001 bar, and it seems to be no harm after that. The result of the DME−LPG mixture is almost exactly the same with the result of LPG. Figure 6 is the overpressure plot relative to distance, obtained by the TNT equivalency model. In the case of CNG and HCNG, the explosion effect of CNG of 5 ton is similar to about 2.7 ton, and HCNG is similar to about 7268
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Figure 6. Distance vs overpressure of LPG and DME−LPG explosions, estimated by the TNT equivalency model.
Figure 7. Distance vs overpressure of CNG and HCNG explosions by the TNT equivalency model.
Table 3. Overpressure Relative to Distance for CNG Explosion by the TNT Equivalency Modela
Table 4. Overpressure Relative to Distance for HCNG (2:8) Explosion by the TNT Equivalency Modela
distance
scaleddistance
overpressure
distance
scaleddistance
overpressure
distance
scaleddistance
overpressure
distance
scaleddistance
overpressure
1 10 20 30 40 50 100
0.071 0.72 1.43 2.15 2.87 3.58 7.17
more than 10 more than 10 2.1 1.1 0.61 0.4 0.14
200 300 500 1000 2000 3000 5000
14.33 21.5 35.83 71.66 143.32 214.98 358.3
0.055 0.032 0.019 0.008 0.0038 0.0025 0.0014
1 10 20 30 40 50 100
0.066 0.66 1.32 1.98 2.64 3.3 6.6
more than 10 more than 10 2.9 1.2 0.65 0.42 0.17
200 300 500 1000 2000 3000 4000
13.2 19.8 33 66 132 198 330
0.058 0.039 0.021 0.009 0.004 0.0029 0.0015
a
a
Distance, m; overpressure, bar.
Distance, m; overpressure, bar.
only to confirm the pattern of distribution and tendency of overpressure. Protection method recommendation from this model could not be performed. (2) The results of PHAST give reasonable simulation when estimating the brief effect of explosion and installing a protecting wall around the facilities. More information of the site such as weather conditions, conditions of release, and properties of materials are required for consideration. (3) The results of FLACS give the 3D distribution of overpressure which reflects more real conditions of the site and accidents such as 3D structure, diffusion, and the flow of air in the space. Due to this reflection, the
from 2 to 12 ms after the ignition. The peak overpressure is 14.06 bar calculated by the TNT equivalency model at the ignition point. After 6 ms from the initial ignition, the overpressure decreased lower than 10 bar, propagating to 10 m from the ignition point. Then, overpressure of about 6.5 bar is confirmed around 15 m from the ignition point for the case of no obstacles existing. 4.5. Discussion on the Difference in the Calculated Values of Overpressure. The discrepancies confirmed from the simulation results out of the selected three methods are as follows: (1) As explained earlier, the results of the TNT equivalency model are bigger than real overpressure of explosion, due to simple comparison to heat of reaction. From these results, it is good 7269
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Figure 8. Distance vs overpressure of LPG and DME−LPG VCE explosions by PHAST.
Figure 9. Distance vs overpressure of LPG and DME−LPG BLEVE explosions by PHAST.
Figure 10. Distance vs overpressure of CNG and HCNG VCE explosions by PHAST.
calculated value is lower than the above two models, but it generates the most realistic results. On the other hand, the results from wrong assumptions may produce useless data to assess the risk that occurred by possible accidents. It is useful when considering an arrangement of facilities or
safety structures to prevent domino effects in hazardous layout of structures from explosion. The results of new energy materials would give valid results only when their physical properties were verified and corrected from real experiments: it needs building 7270
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Figure 11. Distribution of LPG explosion overpressure in the facility.
has a way to create and estimate the properties for combinations of new materials, but the resulting simulations should be used cautiously especially when the materials deviate from conventional gases. While this model supports creation of materials not built in to the distribution version of the code, the results from creation of new materials would not be accurate enough to assess the effects of explosion. 4.6. Guideline of Model Selection Depending on the Problem Requirement. To control risks in the design of the filling station, it is good to analyze the risk by conducting risk assessment. To satisfy the necessary risk level, required protection means could be applied at the optimal location(s) in the facilities, such as protection wall or pressure release panels. There are many safeguards which can reduce the risk in the filling stations. For example, selections of the thickness of the
Figure 12. Overpressure vs time predicted for LPG explosion by FLACS.
additional database or designing experiments to enable the reliable simulations. FLACS, like many process simulators,
Figure 13. Overpressure vs time predicted for CNG and HCNG explosions by FLACS. 7271
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The effective and efficient procedure of assessment estimating risk and setting the protection equipment is the following: After the HAZOP study, simulations are performed according to the given scenarios using an empirical or phenomenological model. Then, sort out some scenarios which need additional protection considerations because of the existing risk of higher pressure over distance. Using these scenarios, thorough quantitative simulation by a CFD-based model is conducted to confirm the distribution of overpressure and pinpoint the most hazardous place. The aftermath of installing the protection devices is simulated, and then, the acceptable level of risk is confirmed. Suggested methods to find safeguards can be used in filling stations when new or revamping designs of them are required. However, the effects of damage reduction could be verified only through the efficient use of the CFD-based models.
Table 5. Summary of Results for DME−LPG PHAST
overpressure 5 ton LPG
TNT equivalency model
VCE
BLEVE
FLACS (VCE)
5.8 bar at 10 m
1 bar at 10 m 18 bar at 10 m 0.026 bar at 0.43 s after the ignition 0.13 bar at 50 m 0.4 bar at 0.1 bar at 50 m 50 m 5 ton DME−LPG 5.3 bar at 10 m 1 bar at 10 m 18 bar at 10 m 0.11 bar at 50 m 0.39 bar at 0.09 bar at 50 m 50 m 40 ton LPG over 10 bar at 1 bar at 10 m 18 bar at 10 m 10 m 0.76 bar at 50 m 1 bar at 50 m 0.4 bar at 50 m 40 ton DME−LPG over 10 bar at 1 bar at 10 m 18 bar at 10 m 10 m 0.70 bar at 50 m 1 bar at 50 m 0.38 bar at 50 m
5. CONCLUSIONS This study analyzed and compared the results of explosion risk prediction by using three representative models for explosion consequence estimation (the TNT equivalency model as the empirical model, PHAST as the phenomenological model, and FLACS as the CFD-based model, listed in increased model complexity and computational and modeling efforts). First, the three models were used and compared in the explosion risk prediction for the conventional LPG and CNG and adapted DME−LPG and HCNG stations. When the overpressures of gas explosion for both LPG and DME−LPG mixtures were calculated, there was no significant difference in resulting values between the simple TNT equivalency model and PHAST simulation. Overpressure plots of LPG and DME−LPG mixtures relative to distance were similar to each other. Likewise, the case of the CNG and HCNG mixtures showed similar calculated results for overpressure of gas explosion. Thus, when supplying the HCNG mixtures in the CNG filling station, the explosion result would be little higher than the case of CNG only, but additional risk of significance is not expected. We also predicted and estimated the exact damages of newenergy refueling facilities’ explosion by running the CFD-based
Table 6. Summary of Results for HCNG overpressure 5 ton CNG
TNT equivalency model PHAST (VCE) over 10 bar at 10 m 1 bar at 10 m
FLACS (VCE) 0.019 at 17 s after the ignition
0.4 bar at 50 m 0.87 bar at 50 m 5 ton HCNG over 10 bar at 10 m 1 bar at 10 m 0.016 at 0.34 s after the ignition 0.42 bar at 50 m 0.97 bar at 50 m 40 ton CNG over 10 bar at 10 m 1 bar at 10 m 1.79 bar at 50 m 0.87 bar at 100 m 40 ton HCNG over 10 bar at 10 m 1 bar at 10 m 1.9 bar at 50 m 0.97 bar at 100 m
protection wall around the facilities or the area of the site would be good to use the empirical or phenomenological model. However, a compact, effective 3D arrangement of equipment in the facility would be possible only when adopting the results from the CFD-based model.
Figure 14. Overpressure propagation by the integrated code of the Gas Dynamics Toolbox and TNT equivalency model. 7272
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(17) Antanovskii, L. K. Solving Multi-Dimensional Problems of Gas Dynamics Using MATLAB. Def. Sci. Technol. Organ. 2008 (18) Angers, B.; Hourri, A.; Bénard, P.; Tessier, P.; Perrin, J. Simulations of Hydrogen Releases from a Storage Tank: Dispersion and Consequences of Ignition. Proceedings of the International Conference on Safety 2005, Pisa, Italy, 2005. (19) Clutter, J. K.; Mathis, J. T. Modeling Environmental Effects in the Simulation of Explosion Events. Int. J. Impact Eng. 2007, 34, 973−989. (20) Pasman, H. J. Why Research into Explosion Mechanisms of Flammable Cloud Is Still Necessary: Reducing Uncertainty Will Make Risk Assessment and Decision Making Stronger. Ind. Eng. Chem. Res. 2011, 51, 7428−7635. (21) Mogi, T.; Horiguchi, S. Explosion and Detonation Characteristics of Dimethyl Ether. J. Hazard. Mater. 2009, 164, 114−119. (22) Brasie, W. C.; Simpson, D. W. Guidelines for Estimating Damage from Chemical Explosions. 3rd National AIChE Meeting, 1968.
FLACS on a three-dimensional structure of the refilling station. On the basis of the results, we compared the difference between the current LPG station and the one using a DME−LPG mixture and investigated how we can reduce the explosion risk effectively. CFD-based complicated models showed the necessary accuracy required for the adoption of the simulation results for safety reviews and corresponding upgrade design of refilling stations. The final results are being adopted as part of new safety regulations for the DME−LPG stations to be operated in Korea.
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This work was supported by the Energy Efficiency & Resources Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea Government Ministry of Knowledge Economy (No. 2011T100200023).
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REFERENCES
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