Syed Tauseef | Pondicherry Central University (original) (raw)
Papers by Syed Tauseef
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Journal of Failure Analysis and Prevention, 2010
Liquefied petroleum gas (LPG) has been in use as household fuel all over the world for several de... more Liquefied petroleum gas (LPG) has been in use as household fuel all over the world for several decades. Until the late 1980s, its use in the developing world was largely confined to the economically well-off strata of the society but it has since spread over a much larger catchment. The increasing use of LPG has enhanced and generalized the risk of a “boiling liquid expanding vapor explosion” (BLEVE). This is evidenced from the reports which appear now and then of a LPG cylinder having exploded in a household, some workshop, or on a bus or a train. In fact some very major tragedies have been triggered by such explosions which also set off fires and cause secondary accidents. This paper describes what BLEVEs are and how can they be controlled. The paper focuses on hazards of BLEVE in large installations which deal with LPG, and other pressure-liquefied gases and discusses the nature, mechanism, and means of control of BLEVEs.
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Anaerobic digestion often generates ‘biogas’ – an approximately 3:1 mixture of methane and carbon... more Anaerobic digestion often generates ‘biogas’ – an approximately 3:1 mixture of methane and carbon dioxide – which has been known to be a ‘clean’ fuel since the late 19th century. But a great resurgence of interest in biogas capture – hence methane capture – has occurred in recent years due to the rapidly growing spectre of global warming. Anthropogenic causes which directly or indirectly release methane into the atmosphere, are responsible for as much as a third of the overall additional global warming that is occurring at present. Hence the dual advantage of methane capture – generating energy while controlling global warming – have come to the fore.This paper presents an overview of the natural and the anthropogenic sources that contribute methane to the atmosphere. In this context it underscores the urgency with which the world must develop and enforce methods and practices to enhance methane capture.
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Journal of Loss Prevention in The Process Industries, 2011
The effectiveness of the application of CFD to vapour cloud explosion (VCE) modelling depends on ... more The effectiveness of the application of CFD to vapour cloud explosion (VCE) modelling depends on the accuracy with which geometrical details of the obstacles likely to be encountered by the vapour cloud are represented and the correctness with which turbulence is predicted. This is because the severity of a VCE strongly depends on the types of obstacles encountered by the cloud undergoing combustion; the turbulence generated by the obstacles influences flame speed and feeds the process of explosion through enhanced mixing of fuel and oxidant. In this paper a CFD-based method is proposed on the basis of the author’s finding that among the various models available for assessing turbulence, the realizable k–ɛ model yields results closer to experimental findings than the other, more frequently used, turbulence models if used in conjunction with the eddy-dissipation model. The applicability of the method has been demonstrated in simulating the dispersion and ignition of a typical vapour cloud formed as a result of a spill from a liquid petroleum gas (LPG) tank situated in a refinery. The simulation made it possible to assess the overpressures resulting from the combustion of the flammable vapour cloud. The phenomenon of flame acceleration, which is a characteristic of combustion enhanced in the presence of obstacles, was clearly observed. Comparison of the results with an oft-used commercial software reveals that the present CFD-based method achieves a more realistic simulation of the VCE phenomena.► A new method is proposed for simulation of vapour cloud explosion (VCE). ► It enables more precise and accurate forecast of the likely consequence of a likely VCE. ► It will provides much more useful inputs for the prevention of VCE than has been possible hitherto.
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Journal of Loss Prevention in The Process Industries, 2011
Quantification of spatial and temporal concentration profiles of vapor clouds resulting from acci... more Quantification of spatial and temporal concentration profiles of vapor clouds resulting from accidental loss of containment of toxic and/or flammable substances is of great importance as correct prediction of spatial and temporal profiles can not only help in designing mitigation/prevention equipment such as gas detection alarms and shutdown procedures but also help decide on modifications that may help prevent any escalation of the event.The most commonly used models – SLAB (Ermak, 1990), HEGADAS (Colenbrander, 1980), DEGADIS (Spicer & Havens, 1989), HGSYSTEM (Witlox & McFarlane, 1994), PHAST (DNV, 2007), ALOHA (EPA & NOAA, 2007), SCIPUFF (Sykes, Parker, Henn, & Chowdhury, 2007), TRACE (SAFER Systems, 2009), etc. – for simulation of dense gas dispersion consider the dispersion over a flat featureless plain and are unable to consider the effect of presence of obstacles in the path of dispersing medium. In this context, computational fluid dynamics (CFD) has been recognized as a potent tool for realistic estimation of consequence of accidental loss of containment because of its ability to take into account the effect of complex terrain and obstacles present in the path of dispersing fluid.The key to a successful application of CFD in dispersion simulation lies in the accuracy with which the effect of turbulence generated due to the presence of obstacles is assessed. Hence a correct choice of the most appropriate turbulence model is crucial to a successful implementation of CFD in the modeling and simulation of dispersion of toxic and/or flammable substances.In this paper an attempt has been made to employ CFD in the assessment of heavy gas dispersion in presence of obstacles. For this purpose several turbulence models were studied for simulating the experiments conducted earlier by Health and Safety Executive, (HSE) U.K. at Thorney Island, USA (Lees, 2005). From the various experiments done at that time, the findings of Trial 26 have been used by us to see which turbulence model enables the best fit of the CFD simulation with the actual findings. It is found that the realizable k–ɛ model was the most apt and enabled the closest prediction of the actual findings in terms of spatial and temporal concentration profiles. It was also able to capture the phenomenon of gravity slumping associated with dense gas dispersion.► A new CFD-based method is presented for modeling dense gas dispersion in presence of obstacles. ► The novelty lies in the use of turbulence model and the manner of resolution of domain geometry. ► Excellent fit of theory with experimental findings.
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Journal of Loss Prevention in The Process Industries, 2011
Past accident analysis (PAA) is one of the most potent and oft-used exercises for gaining insight... more Past accident analysis (PAA) is one of the most potent and oft-used exercises for gaining insights into the reasons why accidents occur in chemical process industry (CPI) and the damage they cause. PAA provides invaluable ‘wisdom of hindsight’ with which strategies to prevent accidents or cushion the impact of inevitable accidents can be developed.A number of databases maintain record of past accidents in CPI. The most comprehensive of the existing databases include Major Hazard Incident Data Service (MHIDAS), Major Accident Reporting System (MARS), and Failure and Accidents Technical Information Systems (FACTS). But each of these databases have some limitations. For example MHIDAS can be accessed only after paying a substantial fee. Moreover, as detailed in the paper, it is not infallible and has some inaccuracies. Other databases, besides having similar problems, are seldom confined to accidents in chemical process industries but also cover accidents from other domains such as nuclear power plants, construction industry, and natural disasters. This makes them difficult to use for PAA relating to CPI. Operational injuries not related to loss of containment, are also often included. Moreover, the detailing of events doesn’t follow a consistent pattern or classification; a good deal of relevant information is either missing or is misclassified.The present work is an attempt to develop a comprehensive open-source database to assist PAA. To this end, information on about 8000 accidents, available in different open-source clearing houses has been brought into a new database named by us PUPAD (Pondicherry University Process-industry Accident Database). Multiple and overlapping accident records have been carefully eliminated and a search engine has been developed for retrieval of the records on the basis of appropriate classification. PUPAD doesn’t aim to replace or substitute the well established databases such as MHIDAS and MARS but, rather, aims to compliment them.► A novel database covering over 8000 records of accidents in the chemical process industry is presented. ► A comparison indicates that the new database can complement the existing ones and help reduce the uncertainties associated with past accident analysis. ► The novelty and widespread utility of the work justifies its publication in the journal.
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Bookmarks Related papers MentionsView impact
Journal of Failure Analysis and Prevention, 2010
Liquefied petroleum gas (LPG) has been in use as household fuel all over the world for several de... more Liquefied petroleum gas (LPG) has been in use as household fuel all over the world for several decades. Until the late 1980s, its use in the developing world was largely confined to the economically well-off strata of the society but it has since spread over a much larger catchment. The increasing use of LPG has enhanced and generalized the risk of a “boiling liquid expanding vapor explosion” (BLEVE). This is evidenced from the reports which appear now and then of a LPG cylinder having exploded in a household, some workshop, or on a bus or a train. In fact some very major tragedies have been triggered by such explosions which also set off fires and cause secondary accidents. This paper describes what BLEVEs are and how can they be controlled. The paper focuses on hazards of BLEVE in large installations which deal with LPG, and other pressure-liquefied gases and discusses the nature, mechanism, and means of control of BLEVEs.
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Anaerobic digestion often generates ‘biogas’ – an approximately 3:1 mixture of methane and carbon... more Anaerobic digestion often generates ‘biogas’ – an approximately 3:1 mixture of methane and carbon dioxide – which has been known to be a ‘clean’ fuel since the late 19th century. But a great resurgence of interest in biogas capture – hence methane capture – has occurred in recent years due to the rapidly growing spectre of global warming. Anthropogenic causes which directly or indirectly release methane into the atmosphere, are responsible for as much as a third of the overall additional global warming that is occurring at present. Hence the dual advantage of methane capture – generating energy while controlling global warming – have come to the fore.This paper presents an overview of the natural and the anthropogenic sources that contribute methane to the atmosphere. In this context it underscores the urgency with which the world must develop and enforce methods and practices to enhance methane capture.
Bookmarks Related papers MentionsView impact
Journal of Loss Prevention in The Process Industries, 2011
The effectiveness of the application of CFD to vapour cloud explosion (VCE) modelling depends on ... more The effectiveness of the application of CFD to vapour cloud explosion (VCE) modelling depends on the accuracy with which geometrical details of the obstacles likely to be encountered by the vapour cloud are represented and the correctness with which turbulence is predicted. This is because the severity of a VCE strongly depends on the types of obstacles encountered by the cloud undergoing combustion; the turbulence generated by the obstacles influences flame speed and feeds the process of explosion through enhanced mixing of fuel and oxidant. In this paper a CFD-based method is proposed on the basis of the author’s finding that among the various models available for assessing turbulence, the realizable k–ɛ model yields results closer to experimental findings than the other, more frequently used, turbulence models if used in conjunction with the eddy-dissipation model. The applicability of the method has been demonstrated in simulating the dispersion and ignition of a typical vapour cloud formed as a result of a spill from a liquid petroleum gas (LPG) tank situated in a refinery. The simulation made it possible to assess the overpressures resulting from the combustion of the flammable vapour cloud. The phenomenon of flame acceleration, which is a characteristic of combustion enhanced in the presence of obstacles, was clearly observed. Comparison of the results with an oft-used commercial software reveals that the present CFD-based method achieves a more realistic simulation of the VCE phenomena.► A new method is proposed for simulation of vapour cloud explosion (VCE). ► It enables more precise and accurate forecast of the likely consequence of a likely VCE. ► It will provides much more useful inputs for the prevention of VCE than has been possible hitherto.
Bookmarks Related papers MentionsView impact
Journal of Loss Prevention in The Process Industries, 2011
Quantification of spatial and temporal concentration profiles of vapor clouds resulting from acci... more Quantification of spatial and temporal concentration profiles of vapor clouds resulting from accidental loss of containment of toxic and/or flammable substances is of great importance as correct prediction of spatial and temporal profiles can not only help in designing mitigation/prevention equipment such as gas detection alarms and shutdown procedures but also help decide on modifications that may help prevent any escalation of the event.The most commonly used models – SLAB (Ermak, 1990), HEGADAS (Colenbrander, 1980), DEGADIS (Spicer & Havens, 1989), HGSYSTEM (Witlox & McFarlane, 1994), PHAST (DNV, 2007), ALOHA (EPA & NOAA, 2007), SCIPUFF (Sykes, Parker, Henn, & Chowdhury, 2007), TRACE (SAFER Systems, 2009), etc. – for simulation of dense gas dispersion consider the dispersion over a flat featureless plain and are unable to consider the effect of presence of obstacles in the path of dispersing medium. In this context, computational fluid dynamics (CFD) has been recognized as a potent tool for realistic estimation of consequence of accidental loss of containment because of its ability to take into account the effect of complex terrain and obstacles present in the path of dispersing fluid.The key to a successful application of CFD in dispersion simulation lies in the accuracy with which the effect of turbulence generated due to the presence of obstacles is assessed. Hence a correct choice of the most appropriate turbulence model is crucial to a successful implementation of CFD in the modeling and simulation of dispersion of toxic and/or flammable substances.In this paper an attempt has been made to employ CFD in the assessment of heavy gas dispersion in presence of obstacles. For this purpose several turbulence models were studied for simulating the experiments conducted earlier by Health and Safety Executive, (HSE) U.K. at Thorney Island, USA (Lees, 2005). From the various experiments done at that time, the findings of Trial 26 have been used by us to see which turbulence model enables the best fit of the CFD simulation with the actual findings. It is found that the realizable k–ɛ model was the most apt and enabled the closest prediction of the actual findings in terms of spatial and temporal concentration profiles. It was also able to capture the phenomenon of gravity slumping associated with dense gas dispersion.► A new CFD-based method is presented for modeling dense gas dispersion in presence of obstacles. ► The novelty lies in the use of turbulence model and the manner of resolution of domain geometry. ► Excellent fit of theory with experimental findings.
Bookmarks Related papers MentionsView impact
Journal of Loss Prevention in The Process Industries, 2011
Past accident analysis (PAA) is one of the most potent and oft-used exercises for gaining insight... more Past accident analysis (PAA) is one of the most potent and oft-used exercises for gaining insights into the reasons why accidents occur in chemical process industry (CPI) and the damage they cause. PAA provides invaluable ‘wisdom of hindsight’ with which strategies to prevent accidents or cushion the impact of inevitable accidents can be developed.A number of databases maintain record of past accidents in CPI. The most comprehensive of the existing databases include Major Hazard Incident Data Service (MHIDAS), Major Accident Reporting System (MARS), and Failure and Accidents Technical Information Systems (FACTS). But each of these databases have some limitations. For example MHIDAS can be accessed only after paying a substantial fee. Moreover, as detailed in the paper, it is not infallible and has some inaccuracies. Other databases, besides having similar problems, are seldom confined to accidents in chemical process industries but also cover accidents from other domains such as nuclear power plants, construction industry, and natural disasters. This makes them difficult to use for PAA relating to CPI. Operational injuries not related to loss of containment, are also often included. Moreover, the detailing of events doesn’t follow a consistent pattern or classification; a good deal of relevant information is either missing or is misclassified.The present work is an attempt to develop a comprehensive open-source database to assist PAA. To this end, information on about 8000 accidents, available in different open-source clearing houses has been brought into a new database named by us PUPAD (Pondicherry University Process-industry Accident Database). Multiple and overlapping accident records have been carefully eliminated and a search engine has been developed for retrieval of the records on the basis of appropriate classification. PUPAD doesn’t aim to replace or substitute the well established databases such as MHIDAS and MARS but, rather, aims to compliment them.► A novel database covering over 8000 records of accidents in the chemical process industry is presented. ► A comparison indicates that the new database can complement the existing ones and help reduce the uncertainties associated with past accident analysis. ► The novelty and widespread utility of the work justifies its publication in the journal.
Bookmarks Related papers MentionsView impact