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Hazards of toluene storage tanks in a petrochemical plant: modeling effects, consequence analysis, and comparison of two modeling programs
2022
Barjoee, Saeed Shojaee | Elmi, Mohammad Reza | Varaoon, Vahid Talebi | Keykhosravi, Seyed Saeed | Karimi, Farshid
The leakage of toluene from damaged tanks can threaten both workers and the environment; ergo, the effects and consequences of toluene leaks can be modeled and quantified to aid in emergency planning and response management. This study modeled the effects and consequences on various scenarios of toluene release via the ALOHA and PHAST programs: evaporation puddle formation, dispersion of toxic and flammable vapor clouds, the distribution of lethal concentrations, and the probability of death from a toluene leak from a height of 6 m of the tank wall. The outputs of the two modeling programs were analyzed and compared. The results showed that the maximum threat zone distances associated with high hazards of toxicity, flammability, and thermal radiation of toluene were respectively 736, 132, and 52 m in ALOHA and 1626, no result, and 239 m for PHAST from the accident point in the downwind. The highest probability of death was 92%, which occurred at a distance of 1 m in the cold seasons. The output values for the PHAST program were higher than those for ALOHA. The results also showed that the survival zone in which the probability of death was low could be determined from a distance of 51 m onwards. Although the assessment of the results indicated no matching between the results obtained by ALOHA and PHAST, the program outputs could still help decision-makers in emergency response planning and the allocation of medical and support services during emergencies.
Mostrar más [+] Menos [-]Effects of solar geometry and operation period on stability of solar desalination systems: a review
2021
Arunkumar, Thirugnanasambantham | Raj, Kaiwalya | Kabeel, Abd-Elnaby | Lee, Sang Joon
The sun is the primary source of life on the earth. The heating effect of the sun provides a more fruitful environment for mankind. In addition, solar energy in the form of thermal radiation has been utilized for solar thermal applications and space heating. With abundant solar radiation, the emergence of the solar desalination has been emerged as a viable solution for water purification by utilizing solar stills. However, solar-powered distillation is relatively a slow process due to the requirement of bulk heating. To suppress thermal conduction to bulk water, various photothermal materials were employed. However, there are many governing parameters which influence the productivity, including solar intensity, cloud, wind, ambient air temperature, humidity, solar absorption of blackened surface, depth of bulk water, feed water type, angle of condensation surface, water film thickness, underneath the condensing surface, and experiment period. Further, systematic and continuous experiments for extended periods are essential for determining the stability and durability of a solar desalination system. The main objective of this article is to review all the experimental studies conducted for two months at minimum up to 1-year duration. In addition, all the SDSs handled in this study further were examined by solar geometrical factors, including day length (DL) and position of the sun or zenith angle (θz). As a result, the sunshine hours, day length, and the solar zenith angle play an important role in the water evaporation rate. Lower solar zenith angle and longer day length (more sunshine hours) are desirable for higher water productivity.
Mostrar más [+] Menos [-]Consequence analysis due to possible ethanol leaks in sugarcane biorefineries
2021
Schmatz, Matheus | da Silva Júnior, Afonso Henrique | Lopes, Toni Jefferson
This study simulated and evaluated the consequences of possible ethanol leaks in a hypothetical sugarcane biorefinery, considering climatic factors in the region of the State of São Paulo-BR. The Gaussian model was used to obtain the results of the hypothetical scenarios. From these values, an empirical mathematical model was established to describe the behavior of the system within the investigated experimental domain. The results obtained the modeling values of the hypothetical scenarios, the statistical treatment for the two responses—a range, slight damage (R1), and a range, high damage (R2), the joint analyses of variables R1 and R2, and the risk classification of catastrophic events. The consequence analysis allowed the calculation and plotting of graphs, such as the areas of thermal radiation range. Among the variables addressed in the study, the diameter of the leakage hole was the most noticeable in the range of thermal radiation. Therefore, it is relevant to make simulations to prevent hazardous material leakages by applying the exact characteristics of the plant to conduct the procedure.
Mostrar más [+] Menos [-]Analysis of long-term degradation behaviour of polyethylene mulching films with pro-oxidants under real cultivation and soil burial conditions
2015
Briassoulis, Demetres | Babou, Epifaneia | Hiskakis, Miltiadis | Kyrikou, Ioanna
Apart from the conventional polyethylene and the bio-based or mainly bio-based biodegradable in soil mulching films, polyethylene mulching films of controlled degradation in soil are already used in agriculture. The use of special pro-oxidants as additives is expected to accelerate the abiotic oxidation and the subsequent chain scission of the polymer under specific UV radiation or thermal degradation conditions, according to the literature. The role of pro-oxidants in the possible biodegradation of polyethylene has been theoretically supported through the use of controlled laboratory conditions. However, results obtained in real soil conditions, but also several laboratory test results, are not supporting these claims and the issue remains disputed. Mulching films made of linear low-density polyethylene (LLDPE) with pro-oxidants, after being used for one cultivation period in an experimental field with watermelon cultivation, were buried in the soil under real field conditions. This work presents the analysis of the degradation of the mulching films during the cultivation period as compared to the corresponding changes after a long soil burial period of 8.5 years. The combined effects of critical factors on the photochemical degradation of the degradable mulching LLDPE films with pro-oxidants under the cultivation conditions and their subsequent further degradation behaviour in the soil are analysed by testing their mechanical properties and through spectroscopic and thermal analysis.
Mostrar más [+] Menos [-]Evaporation of a wooded slope at the ARINUS site Schluchsee
1996
Mayer, H. | Fritsch, J.