Universiti Teknologi Petronas

About: Universiti Teknologi Petronas is a education organization based out in Ipoh, Malaysia. It is known for research contribution in the topics: Adsorption & Ionic liquid. The organization has 6127 authors who have published 11284 publications receiving 119400 citations.

Process route index (PRI) to assess level of explosiveness for inherent safety quantification

Abstract: The fundamental concept of quantification of inherent safety level is based on the ranking of chemical process routes. Three pioneering inherent safety indices (i.e. PIIS, ISI and i-Safe) are based on this concept and have treated the chemicals in the process system as individual components and not as mixture. These indices lack of ability to reflect the contribution of individual components in the mixture which may affect the quantification of the inherent safety level for process route selection. A new index known as process route index (PRI) is proposed for inherent safety quantification to address the highlighted issues. Level of explosiveness is used for quantification of the inherent safety level for process route selection to illustrate the importance of the individual contribution of the components in the mixture. PRI is developed based on fundamental process parameters that influence the explosion of chemical processes. One of the important criteria for the quantification of the level of explosiveness is to determine the combustibility of the chemicals based on the difference between lower flammability limit (LFL) and upper flammability limit (UFL). The current available indices do not consider the influence of process temperature and pressure on the UFL and LFL. The PRI is developed with the function of temperature and pressure for the quantification of the explosiveness level. The PRI is benchmarked against the published results of the other indices using HYSYS simulation case studies to produce methyl methacrylate acid (MMA) by various process routes. Benchmarking results conclude that PRI is in close agreement with other inherent safety indices and also able to make differentiation between inherent safety level of process routes which were previously indistinguishable.

Effect of antecedent rainfall on pore‐water pressure distribution characteristics in residual soil slopes under tropical rainfall

Abstract: Characteristics of changes in pore-water pressure distribution are the main parameters associated with slope stability analysis involving unsaturated soils, which are directly affected by the flux boundary conditions (rainfall infiltration, evaporation and evapo-transpiration) at the soil-atmosphere interface. Four slopes were instrumented in two major geological formations in Singapore to provide real-time measurements of pore-water pressures and rainfall events on the slopes. The field monitoring results were analysed to characterize pore-water pressure distributions under various meteorological conditions and to study the effect of antecedent rainfall on pore-water pressure distributions in typical residual soil slopes under tropical climate. Slope stability analyses were also conducted for the best and worst pore-water pressure distributions recorded in each slope to determine the range of factor of safety for the slopes. Results indicate that, antecedent rainfall, initial pore-water pressures prior to a significant rainfall event as well as the magnitude of the rainfall event play a crucial role in the development of the worst pore-water pressure condition in a slope. The role of antecedent rainfall in the development of the worst pore-water pressure condition was found to be more significant in residual soils with low permeability as compared with that in residual soils with high permeability. Pore-water pressure variation due to rainfall was found to take place over a wide range in residual soils with higher permeability as compared to residual soils with lower permeability. The worst pore-water pressure profiles occurred when the total rainfall including the 5-day antecedent rainfall (in most cases) reached a maximum value during a wet period. The factor of safety of residual soils with low permeability was found to be unaffected by the worst pore-water pressure condition.