LNG Safety Research: FEM3A Model Development

The initial scope of work for this project included: (1) Improving the FEM3A advanced turbulence closure module, (2) Adaptation of FEM3A for more general applications, and (3) Verification of dispersion over rough surfaces, with and without obstacle using the advanced turbulence closure module. These work elements were to be performed by Chemical Hazards Research Center (CHRC), Department of Chemical Engineering, University of Arkansas as a subcontractor to Gas Technology Institute (GTI). The tasks for GTI included establishment of the scientific support base for standardization of the FEM3A model, project management, technology transfer, and project administration. Later in the course of the project, the scope of work was modified by the National Energy Technology Laboratories (NETL) to remove the emphasis on FEM3A model and instead, develop data in support of NETL's FLUENT modeling. With this change, GTI was also instructed to cease activities relative to FEM3A model. GTI's technical activities through this project included the initial verification of FEM3A model, provision of technical inputs to CHRC researchers regarding the structure of the final product, and participation in technical discussion sessions with CHRC and NETL technical staff. GTI also began the development of a Windows-based front end for the model but the work was stopped due to the change in scope of work. In the meantime, GTI organized a workshop on LNG safety in Houston, Texas. The workshop was very successful and 75 people from various industries participated. All technical objectives were met satisfactorily by Dr. Jerry Havens and Dr. Tom Spicer of CHRC and results are presented in a stand-alone report included as Appendix A to this report

LNG Safety Research: FEM3A Model Development

ABSTRACT This quarterly report for DE-FG26-04NT42030 covers a period from January 1, 2006 to March 31, 2006. GTI's activities during the report quarter were limited to administrative work. The work at the University of Arkansas continued in line with the initial scope of work and the identified questions regarding surface to cloud heat transfer as being largely responsible for the instability problems previously encountered. A brief summary of results is discussed in this section and the complete report from University of Arkansas is attached. TABLE OF CONTENTS EXECUTIVE SUMMARY Work continued to address numerical problems experienced with simulation of lowwind-speed, stable, atmospheric conditions with FEM3A. Steps 1 through 8 in the plan outlined in the first Quarterly report have been completed successfully for the FEM3A model utilizing the Planetary Boundary Layer (PBL) turbulence closure model. Researchers at the University of Arkansas have solved the problems related to stability of the simulations at regulatory conditions of low wind speed and stable atmospheric conditions with FEM3A using the PBL model, and are continuing our program to verify the operation of the model using an updated, verified, version of the k-epsilon turbulence closure model which has been modified to handle dense gas dispersion effects. EXPERIMENTAL University of Arkansas experienced delays in their experimental efforts to determine the spectral analysis of the turbulence in the wind tunnel as requested by representatives from DOE-NETL, but they believe that problem is solved now and expect to commence with the experimental program in May. The experimental program will focus on measurement of velocities and gas concentrations in the wake region of an LNG tank for use in our CFD model validation efforts, and it will provide the turbulence spectrum for the wind tunnel approach flow. Given the no-cost time extension granted to September 30, 2006, we are on track to finish the contract requirements on schedule. The primary purpose of this task was to repeat and extend former experiments using uniform roughness elements covering the wind tunnel floor to create turbulence properties similar to field scale wind conditions. The roughness used had already been characterized in a related research program; consequently, only the gas concentration 4 measurements will have to be repeated. The resulting data set(s) will be a valuable addition to the data archives demonstrating the FEM3A model for application to LNG vapor dispersion prediction. There are strong indications that the experimental data from the wind tunnel would be more applicable to field conditions, and therefore more useful for model validation, when the floor is artificially roughened. RESULTS AND DISCUSSION Data from experimental work will be used to verify the FEM3A model for application involving dispersion over rough surfaces (for example, suburban housing) with and without the presence of obstacles such as tank and/or dike structures and industrial buildings. The end product will be an advanced turbulence closure model (for describing the turbulent mixing involved in the dispersion process) that will allow for more realistic description of dispersion problems with obstacles and terrain features of greater complexity (the real world). CONCLUSION Researchers at the University of Arkansas have initiated an experimental program to measure velocities in the wake region of an LNG tank. They are also continuing to address the need for changes in the turbulence closure methods to bring the model predictions into closer alignment with the overall wind tunnel results. We have solved the problems related to stability of the simulations at regulatory conditions of low wind speed and stable atmospheric conditions with FEM3A using the PBL model, and are continuing our program to verify the operation of the model using an updated, verified, version of the k-epsilon turbulence closure model which has been modified to handle dense gas dispersion effects. We anticipate that our experience with the turbulence closure models used in FEM3A, particularly the advanced k-epsilon model which considers extreme density stratification effects upon dispersion, will be directly relevant to DOE's efforts to verify the FLUENT model, or any other CFD model, for possible application to LNG vapor dispersion under 49 CFR 193 and NFPA 59A. We have experienced delays in our experimental efforts to determine the spectral analysis of the turbulence in the wind tunnel as requested by representatives from DOE-NETL, but we believe that problem is solved now, and we expect to commence with the experimental program in May. The experimental program will focus on measurement of velocities and gas concentrations in the wake region of an LNG tank for use in our CFD model validation efforts, and it will provide the turbulence spectrum for the wind tunnel approach flow. Given the no-cost time extension granted to September 30, 2006, we are on track to finish the contract requirements on schedule. simulations of stably stratified conditions were subject to numerical stability problems. We were confident that such problems could be eliminated, and research has been underway to modify the turbulence closure model as well as certain boundary condition inconsistencies that had been identified and to verify the model changes by conducting experiments in the University of Arkansas' Ultra-Low-Speed wind tunnel. This was a high priority requirement since the normal application of the code for compliance with the regulation, as well as for application to counter-terrorism issues, frequently require the simulations to be made for such conditions, which are often considered worst-case. The FEM3A code has been modified so that, using the presently recommended planetary boundary layer (PBL) turbulence closure model, it will operate correctly when the regulatory conditions of 2 m/s wind (@10 m elevation) and F category atmospheric stability are specified. Present efforts are underway to extend this operability to the model using the k-epsilon turbulence closure model, as it is anticipated that eventually the k-epsilon model, corrected to account for extreme density stratification, will be recommended to succeed the PBL model when the code is used to predict dispersion influenced by terrain features and or obstacles. Task B -Verification for Dispersion over Rough Surfaces With and Without Obstacles Previous (to this contract) experiments in the CHRC wind tunnel to validate the FEM3A model prediction of the effect of the presence of tank and dike structures utilized a smooth wind tunnel floor. But further research in the CHRC wind tunnel indicated that the presence of the smooth floor combined with the low wind speeds required to simulate the dense gas effects involved in LNG vapor dispersion can result in the tendency for the boundary layer near the floor to laminarize. Under such conditions the wind tunnel flow is not similar to the atmospheric wind flow because field conditions are normally fully 13 turbulent (i.e., laminarization does not normally occur at field scale). There are strong indications that the experimental data from the wind tunnel would be more applicable to field conditions, and therefore more useful for model validation, if the floor were artificially roughened. The primary purpose of this task was to repeat and extend former experiments using uniform roughness elements covering the wind tunnel floor to create turbulence properties similar to field scale wind conditions. The roughness used in this program had already been characterized in a related research program conducted in cooperation with the Environmental Protection Agency; consequently, only the gas concentration measurements had to be repeated. The resulting data set(s) will be a valuable addition to the data archives demonstrating the FEM3A model for application to LNG vapor dispersion prediction. Data from this Task will be used to verify the FEM3A model for application involving dispersion over rough surfaces (for example, suburban housing) with and without the presence of obstacles such as tank and/or dike structures and industrial buildings. The product of this task will be an advanced, k-epsilon, turbulence closure model (for describing the turbulent mixing involved in the dispersion process) that will allow for more realistic description of dispersion problems with obstacles and terrain features of greater complexity (the real world). Task C -Adapting the FEM3A Model for More General Application As more complex applications of the FEM3A model are proposed, it was anticipated that there will be additional questions that can best be addressed by experimentation in the CHRC wind tunnel. The major advantage of this approach is that the specific questions regarding the application of the model to different scenarios can be addressed experimentally without having to recreate all of the experimental conditions in the real scenario, and without the high cost and insufficient controllability that is inherent in larger scale field tests. FEM3A simulations of more complex scenarios will inevitably require experimental verification efforts, and the continued availability of the CHRC wind tunnel for such verification is a necessary adjunct for the successful standardization of the FEM3A model, or of any alternative model, for more general application. Examples of complex scenarios that will be considered are evaluations of vapor fences for containment of flammable gases and aerosols, scenarios containing multiple obstacles, and major terrain features. Task D -Provide assistance and wind tunnel data to DOE for FLUENT development CHRC was requested to provide additional wind-tunnel dense gas dispersion data that could be used generally for verification of computational fluid dynamics (CFD) computer models for predicting LNG vapor dispersion influenced by terrain features and or obstacles, and to provide specific assistance to DOE in its consideration of FLUENT as a recommended alternative (to FEM3A) CFD model for approval by the DOT Administrator under 49 CFR 193 and NFPA 59A. 14 3.0 PROGRAM TIME SCHEDULE Tasks A and B were pursued concurrently because they are interrelated However, preparations for Task A, which are computational in nature, were initiated first, with concurrent experimental validation efforts immediately following. Task A was completed in quarter (Q6) for the FEM3A model using the PBL turbulence closure model. We are still working on the stability problem for the FEM3A model using the kepsilon turbulence closure model. Tasks B, C, and D constituted the primary efforts during the last two Quarters, as all three require continuing experimental work. WORK PERFORMED DURING JANUARY-MARCH 2006 (QUARTER 8) We continued to work on the verification of the FEM3A model using the k-epsilon turbulence closure scheme as well as to work to solve the stability problems experienced with the model (also using the k-epsilon closure model) applied to regulatory conditions of low wind speed and stable atmospheric conditions. We commenced work to determine the spectral analysis of the turbulence in the wind tunnel approach flow as requested by representatives from DOE-NETL during their visit during the sixth quarter as well as to measure near field gas concentrations and velocities (in the wake of the tank and near the point at which gas overflows the dike), but that work was delayed because of equipment problems with our hot wire anemometry system. We anticipate restarting those experiment tasks in May, and having received notice that the contract will be extended at no cost to September 30, we are on schedule to complete the program by the new contract end date. NEW DEVELOPMENTS RELATIVE TO 49 CFR 193 AND NFPA 59A During the course of this contract there have been new and critically important developments regarding the use of models in general, and CFD models in particular, for determining vapor cloud exclusion zones for onshore LNG facilities as required by 49 CFR 193 and NFPA 59A. 15 It is now generally accepted that vapor cloud exclusion zones determined using the SOURCE5 model to determine the input LNG vapor rate to DEGADIS are in error, as SOURCE5 does not provide for mixing of air with LNG vapor evolved inside the impoundment or the dike/vapor fence system. This is extremely important as there are a number of proposed import facilities which have already been approved using this erroneous procedure, and it is now understood that the method (which ignores LNG vapor mixing with air in the impounded area) is expected to systematically underpredict (predict too short) vapor cloud dispersion zones, resulting in failure to protect the public as intended by 49 CFR 193 and NFPA 59A. We think it particularly important to highlight this issue now, as we expect this finding to be applicable to any model that is considered for use by 49 CFR 193 and NFPA 59A for predicting such vapor cloud dispersion scenarios. Consequently, we are requesting that this information be provided the Department of Transportation and the National Fire Protection Association (the agencies which promulgated 49 CFR 193 and NFPA 59A, respectively) immediately so that they are advised of this critical situation. A paper entitled " LNG Vapor Cloud Exclusion Zones for Spills Into Impoundments", published in the AICHE's Process Safety Progress, which details the arguments described summarily herein, is attached as Appendix A. Based on our experience gained with FEM3A during this two-year contract, we are now confident that simulations of time-limited LNG releases dispersing downwind of impoundment and dike systems cannot be assumed to give the maximum distance (as a function of wind speed) for the low wind speed, stable atmospheric conditions allowed (optionally) by 49 CFR 193 and NFPA 59A. It is now clear, and it has been demonstrated in wind tunnel and field test programs, that the "scooping" action of the wind in entraining LNG vapor/air mixtures from impoundment/dike systems is expected to increase with higher wind speeds, thus tending to lengthen the exclusion zone by increasing the amount and rate at which LNG vapor moves downwind. But since the dispersion downwind of the dike is also expected to be enhanced by greater wind speeds, thus tending to decrease the length of the exclusion zone, it is anticipated that these competing effects will result in the maximum distances to the limiting, safe gas concentration occurring at an intermediate wind speed. We are continuing to investigate these effects quantitatively, but we believe it is critically important to highlight this issue now, as we expect this finding to apply to any CFD code that is approved for use by 49 CFR 193 and NFPA 59A -and because reliance on simulations at low wind speed, stable conditions allowed currently by 49 CFR 193 are likely to underestimate the requirements for vapor cloud exclusion zones, thus having the potential to endanger the public to greater distances. Consequently, as we believe this finding suggests that the current regulations, which assume that the worst case vapor cloud travel occurs at low wind speeds (the regulation allows the project applicant to opt for the default use of 2 m/s wind speed along with F stability as worst case), do not adequately provide for public safety, we are also requesting here that this information be provided the Department of Transportation and the National Fire Protection Association immediately so that they are advised of this critical situation. We note that the thermal radiation exclusion zones are already required to be determined at the wind speed that would give the maximum exclusion zone impact -and we recommend ABSTRACT LNG spills on land are most likely to happen in dike/impoundment areas, introducing the need to consider effects of dike/impoundment walls on vapor holdup and dispersion. The DEGADIS and FEM3A models are approved for determination of vapor cloud exclusion zones in 49 CFR 193, but DEGADIS is limited to prediction of dispersion from area sources over flat, obstacle-free terrain and is therefore not directly applicable to spills in dike/impoundment areas. However, FEM3A, which is a computational fluid dynamics (CFD) model, is directly applicable. Before FEM3A was approved, ad hoc methods were widely used to determine input conditions for DEGADIS to estimate dispersion downwind of a dike system for such releases. Vapor holdup and mixing with air in a dike system has been studied in wind tunnel and field experiments, and the fallacy of using an overly simplistic estimation of the time and rate of vapor cloud overflow has been demonstrated. In some cases, these ad hoc methods have resulted in exclusion zone determinations that do not provide for public safety as intended by 49 CFR 193. This paper summarizes the current state of knowledge about this important vapor dispersion scenario, including key experimental data that address the question. Applications of FEM3A to determine exclusion zones for a hypothetical spill within a typical dike/tank configuration, as well as shortcutuse of FEM3A to describe vapor overflow from the same impoundment for use as input information for DEGADIS simulation of the dispersion downwind from the dike, are illustrated

FEM3A Model Development Quarterly Report: 2005-10

This quarterly report for DE-FG26-04NT42030 covers a period from October 1, 2005 to December 31, 2005. GTI's activities during the report quarter were limited to administrative work. The work at the University of Arkansas continued in line with the initial scope of work and identified the questions regarding surface to cloud heat transfer as being largely responsible for the instability problems previously encountered. A brief summary of results is included in this section and the complete report from University of Arkansas is attached as Appendix A

FEM3A Model Development Quarterly Report: 2005-07

Work has continued to address numerical problems experienced with simulation of low-wind-speed, stable, atmospheric conditions with FEM3A. Steps 1 through 8 in the plan outlined in the first Quarterly report have been satisfied. Researchers at the University of Arkansas have all indications that the important problems related to stability of the simulations at regulatory conditions of low wind speed and stable atmospheric conditions have been resolved. This quarterly report for DE-FG26-04NT42030 covers a period from July 1, 2005 to September 31, 2005. GTI's activities during the report quarter were limited to administrative work. The work at the University of Arkansas continued in line with the initial scope of work and identified the questions regarding surface to cloud heat transfer as being largely responsible for the instability problems previously encountered. A brief summary of results is included in this section and the complete report from University of Arkansas is attached as Appendix A

Pre-demonstration Development of Controlled-Release Corrosion Inhibitors and Healing Agents as Alternatives to Hexavalent Chromium

This Limited Scope Study was directed to achieve the following objectives:(1) Scale-up of materials that can meet MIL-PRF-23377 (solvent-based primer).(2) Provide evidence of resistance to aircraft alkaline cleaners and deicing fluids.(3) Provide formulation for initial ecological and toxicity screening.(4) Submit an interim report that will provide the basis for a future ESTCP demonstration effort.The encapsulation procedure for two corrosion inhibitors was scaled up from lab scale to 2.0 kg. This scale will accommodate high volume production of coatings with encapsulated corrosion inhibitors for large surface areas during a follow on ESTCP demonstration effort.Test results provided evidence of resistance to alkaline cleaners and aircraft deicing fluids and compliance with MIL-PRF-23377. All the MIL-PRF-23377 requirements were met with the exception of the adhesion requirement, in top coated panels, and the flexibility requirement. Work on solving these two problems will be done prior to validation and demonstration of the technology. An initial ecological and toxicity screening identified several factors that were not critical to the acceptance of the encapsulated corrosion inhibitor. This new technology will lead to environmentally friendly alternatives to hexavalent chromium that will enable DoD to protect its assets. Field demonstration, licensing, qualification, and commercialization will allow its real world utilization

Living the punk life in Green Bay, Wisconsin: exploring contradiction in the music of NOFX

This paper studies song lyrics from three mid-period songs written and performed by Californian punk band NOFX. I discuss NOFX’s skilful exploration of contradiction in the three selected songs, two of which are character studies of a single young male individual. The questions that the songs pose in true dialectical fashion (but do not definitively answer) include: Is it possible to maintain the carefree existential existence of the archetypal punk rocker in the face of the constraints imposed by suburban life and the voices of middle-class moderation? Can a Jewish gang in Fairfax, Los Angeles simultaneously affirm group self-identity, defend its turf, and practise its (marginalized) religion? Can a young man enjoy Christianity because it makes his life ‘seem less insane’ whilst simultaneously taking control of his life and not being a Christian sheep? NOFX poses these questions in admirable dialectical fashion, allows us to reflexively examine the issues involved, and form our own conclusions. The band rarely descends into moralism but moral values underpin NOFX’s worldview. Above all, NOFX tries to maintain a sophisticated but precarious ‘both/and’ rather than ‘either/or’ approach to each one of the questions posed in this abstract. Clever lyrics, which highlight the contradictions that a punk rocker must face whilst living in suburban America, have become one of the band’s most loved and most enduring themes