THERMAL AND OVERPRESSURE HAZARDS MODELLING AND SIMULATION: A CASE STUDY OF REFINERY FIRED HEATER

2021 ◽  
Vol 36 (1) ◽  
pp. 67-76
Author(s):  
H. Jamilu ◽  
U. Abubakar-Zaria ◽  
S. M. Shuwa
Keyword(s):  
Flame Length ◽  
Hole Size ◽  
Atmospheric Conditions ◽  
Liquefied Petroleum Gas ◽  
Radiation Level ◽  
Blow Down ◽  
Alarm Systems ◽  
Operational Life ◽  
Flash Fire

Crude oil-fired heaters are associated with considerable fire and explosion hazards. The heaters present higher risks at later operational life due to ageing, wear and obsolescence. It is therefore important to re-evaluate such heaters to determine the adequacy or otherwise of the existing safeguards. This paper presents results of studies on hazard levels in aged fired heaters through quantitative consequence modeling method. A number of credible failure scenarios were considered. In particular, characteristics of potential jet fires due to Liquefied Petroleum Gas (LPG) leaks from hole sizes: 15, 30, 50 and 100 mm were investigated. For the 100 mm hole size, it was found that thermal radiation level of up to 37.5 kW/m2 could be experienced within 25 m radius of the heater, which is enough to affect nearby operators severely and could also adversely affect critical pieces of equipment around. Fireball potential with peak thermal density of about 12.5 kW/m2 was also observed within 2 m radius. For the 100 mm hole size, lower flammability limit of the fuel could be attained within 16 m downwind which poses flash fire risks. Overpressures of 1.02, 1.14 and 1.21 bar could be experienced at 30, 6 and 4 m respectively away from the fired heater which could result in partial demolition of structures that are within the radius.Overall, the results indicate that the risk profile is very sensitive to leak sizes, operating and atmospheric conditions as well as the fuel quantity being held, among others. For the chosen case study, higher integrity protection layers, in form of safety instrumented systems, relief, blow down and alarm systems, are recommended. Keywords: Downwind distance; Consequence modeling; Radiation intensity; Flame length; Overpressure; Toxicity; Liquefied Petroleum Gas.

Modelling of accidental phenomena related to leakage and tank rupture of a vehicle converted to LPG

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohamed Seddik Hellas ◽  
Chaib Rachid ◽  
Ion Verzea
Keyword(s):  
Risk Analysis ◽  
Climatic Conditions ◽  
Atmospheric Conditions ◽  
Human Beings ◽  
Liquefied Petroleum Gas ◽  
Preventive Action ◽  
Content Type ◽  
Quantitative Risk Analysis ◽  
Flash Fire ◽  
Accident Scenarios

Purpose Liquefied petroleum gas (LPG), known by its ecological qualities, making Algeria has since the 1980s carried out a policy of development of LPG fuel in substitution of traditional fuels and especially petrol. However, following a series of accidents (fires, explosions, etc). that occurred in 1999, 20 years after the introduction of the LPG in France these incidents led to the search for the strengthening of the safety of the installations by better or new technical and/or organizational measures. This strategy consists in establishing a balance between environmental protection and economic profitability while ensuring the safety aspect. Design/methodology/approach The approach used is quantitative risk analysis authors have identified the potential accident scenarios that consist of leakage and rupture of tanks depend on bow tie. According to the latter using PHAST software, to model these scenarios (thermal, overpressure and dispersion) and their effects on human beings and goods. Findings In this paper, it was noted that there are scenarios such as (jet fire, dispersion), are affected by atmospheric conditions (wind speed humidity), the stronger the wind, the higher the LPG spread unlike instant scenarios (1.3 s for the fireball and millisecond for the explosion) that have not been related to climatic conditions because they have a short duration on the one hand, and on the other hand, a safe distance is given in each phenomenon. Finally, some instructions for drivers and installers have been identified by protective and preventive action. Originality/value Based on a quantitative risk analysis, this work involves modelling potential accident scenarios such as (fireball, jet fire, flash fire and explosion) in the event of a gas leak and rupture in the tank. It aims to sensitize drivers and LPG kit installers, even to get a clear view on these accidental phenomena and how to avoid them.

Minimizing the cost of wildland fire suppression: a model with uncertainty in predicted flame length and fire-line width produced

1994 ◽  
Vol 24 (6) ◽  
pp. 1253-1259 ◽  
Author(s):  
Romain Mees ◽  
David Strauss ◽  
Richard Chase
Keyword(s):  
Line Width ◽  
Wildland Fire ◽  
Fire Suppression ◽  
Flame Length ◽  
Burned Area ◽  
Expected Cost ◽  
Control Time ◽  
The Cost ◽  
Attack Strategy

We describe a model that estimates the optimal total expected cost of a wildland fire, given uncertainty in both flame length and fire-line width produced. In the model, a sequence of possible fire-line perimeters is specified, each with a forecasted control time. For a given control time and fire line, the probability of containment of the fire is determined as a function of the fire-fighting resources available. Our procedure assigns the resources to the fire line so as to minimize the total expected cost. A key feature of the model is that the probabilities reflect the degree of uncertainty in (i) the width of fire line that can be built with a given resource allocation, and (ii) the flame length of the fire. The total expected cost associated with a given choice of fire line is the sum of: the loss or gain of value of the area already burned; the cost of the resources used in the attack; and the expected loss or gain of value beyond the fire line. The latter is the product of the probability that the chosen attack strategy fails to contain the fire and the value of the additional burned area that would result from such a failure. The model allows comparison of the costs of the different choices of fire line, and thus identification of the optimal strategy. A small case study is used to illustrate the procedure.

scholarly journals Growth of nucleation mode particles in the summertime Arctic: a case study

2016 ◽  
Vol 16 (12) ◽  
pp. 7663-7679 ◽  
Author(s):  
Megan D. Willis ◽  
Julia Burkart ◽  
Jennie L. Thomas ◽  
Franziska Köllner ◽  
Johannes Schneider ◽  
...  
Keyword(s):  
Cloud Condensation Nuclei ◽  
Methanesulfonic Acid ◽  
Lower Troposphere ◽  
Atmospheric Conditions ◽  
Aerosol Formation ◽  
Radiative Balance ◽  
Nucleation Mode ◽  
Cloud Properties ◽  
Marine Influence

Abstract. The summertime Arctic lower troposphere is a relatively pristine background aerosol environment dominated by nucleation and Aitken mode particles. Understanding the mechanisms that control the formation and growth of aerosol is crucial for our ability to predict cloud properties and therefore radiative balance and climate. We present an analysis of an aerosol growth event observed in the Canadian Arctic Archipelago during summer as part of the NETCARE project. Under stable and clean atmospheric conditions, with low inversion heights, carbon monoxide less than 80 ppbv, and black carbon less than 5 ng m−3, we observe growth of small particles,  <  20 nm in diameter, into sizes above 50 nm. Aerosol growth was correlated with the presence of organic species, trimethylamine, and methanesulfonic acid (MSA) in particles ∼ 80 nm and larger, where the organics are similar to those previously observed in marine settings. MSA-to-sulfate ratios as high as 0.15 were observed during aerosol growth, suggesting an important marine influence. The organic-rich aerosol contributes significantly to particles active as cloud condensation nuclei (CCN, supersaturation  =  0.6 %), which are elevated in concentration during aerosol growth above background levels of ∼ 100 to ∼ 220 cm−3. Results from this case study highlight the potential importance of secondary organic aerosol formation and its role in growing nucleation mode aerosol into CCN-active sizes in this remote marine environment.

scholarly journals Variation of diurnal Turbulence Kinetic Energy using sonic anemometer observation: a case study Ledeng, Bandung

2018 ◽  
Author(s):  
Sandy Hardian Susanto Herho ◽  
Dasapta Erwin Irawan
Keyword(s):  
Kinetic Energy ◽  
Diurnal Variation ◽  
Wind Velocity ◽  
Sonic Anemometer ◽  
Diurnal Variations ◽  
Turbulence Kinetic Energy ◽  
Atmospheric Conditions

Sonic anemometer observation was performed on 29 - 30 September 2014 in Ledeng, Bandung to see diurnal variations of Turbulence Kinetic Energy (TKE) that occurred in this area. The measured sonic anemometer was the wind velocity components u, v, and w. From the observation result, it can be seen that the diurnal variation that happened was quite significant. The maximum TKE occurs during the daytime when atmospheric conditions tend to be unstable. TKE values were small at night when atmospheric conditions are more stable than during the daytime.

An Investigation of Microwave Link Degradation due to Atmospheric Conditions (A Case Study of Akure-Owo Digital Microwave Link)

2009 ◽  
Vol 62-64 ◽  
pp. 159-165 ◽  
Author(s):  
P.O. Otasowie ◽  
F.O. Edeko
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Error Rates ◽  
Atmospheric Conditions ◽  
Bit Error Rates ◽  
Data Acquisition Software ◽  
Model Equations ◽  
June July ◽  
Microwave Link

This work investigates the microwave link degradation due to atmospheric conditions on the Akure-Owo Digital Microwave Link. Microwave line of sight measurements were carried out between January and December 2005 with a data acquisition software (PROCOMM PLUS SOFTWARE). The data collected were analyzed using MATLAB 7.0 SOFTWARE program to determine the months of the year that has the highest degradation due to atmospheric conditions and also the months of the year that has the highest bit error rates. The result showed that the months of January, June, July, August and September have the worst signal degradation of -0.97dbm, -2.0dbm, -3.97dbm, -3.97dbm, -1.97dbm. respectively. The result also showed that the bit error rates are good and acceptable throughout the months of the year. A model equation was developed to predict the signal strength received and the bit error rate in the microwave link investigated, when atmospheric conditions are taken into consideration. The results of the predicted model were validated by field data and the results obtained showed an error of -0.2% for the received signal level and zero error for the bit error rate which means that the developed model equations can be used to accurately predict the link degradation parameters.

Relationship between meningitis occurrence and atmospheric conditions over the African meningitis belt

2020 ◽  
Author(s):  
Cheikh Dione ◽  
Mame Diarra Diouf ◽  
Bob Alex Ogwang ◽  
Elijah Adesanya Adefisan ◽  
Steve Woolnough ◽  
...  
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Lassa Fever ◽  
Atmospheric Conditions ◽  
Numerical Weather ◽  
Endemic Diseases ◽  
Meningitis Belt ◽  
Weather And Climate

&lt;p&gt; The alternation of seasons over tropical northern Africa is associated with the occurrence of devastating diseases such as meningitis, Lassa fever and malaria. These tropical diseases are associated with specific atmospheric conditions. Thus, meningitis is one of the most endemic diseases observed over this region with a prevalence period up to 7 months (December-June). Previous studies based on the link between atmospheric conditions and the occurrence of meningitis outbreaks have shown that this disease develops under dry and dusty atmospheric conditions which are difficult to represent in numerical weather and climate models. However, the onset, breakup, and sub-seasonal variability of meningitis outbreaks are not well documented. The objective of this study is to identify the local and synoptic drivers favoring the large occurrence of this disease over the meningitis belt in order to improve its predictability by numerical weather and climate models on intra-seasonal and seasonal timescales. This study focuses on two cases studies of meningitis epidemics over Niger in 2009 and 2015. The case study of 2009 started early with a duration of more than eight weeks. The second case study was shorter than the first one. It took three weeks and was observed at the end of the dry season. Based on ERA5 data, surface dust concentration observations and satellite data, a further analysis of the role of climate metrics on the triggering of meningitis epidemics on intra-seasonal timescales at local and large scale atmospheric conditions will be presented.&lt;/p&gt;

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