Hazard control management on optimization layout of vent stack at offshore platform

The flaring is a normal practice in the oil and gas industry to achieve a safe and reliable process during the emergency situation. This situation is a routine practice for oil and gas production by controlled burning of natural gas. The burning process can cause hazards by explosion or at the very least surrounding environment will be affected by heat radiation during vent stack burning operation. Hence, investigation of the gas flaring produced by the vent stack is needed to tackle these problems. This paper presents designing a safe vent stack position in the limited space of oil and gas platform with considered the heat radiation produced by the vent stack. The simulation will be done by using flaresim software to predict the heat contour, heat radiation, and gas dispersion. The results proved that the optimal position of vent stack with water shield gives a better heat radiation

Microalgae biorefinery alternatives and hazard evaluation

Biodiesel production based on microalgae and using carbon dioxide as feedstock constitutes an attractive biofuel alternative. Technology development and process optimization are necessary to minimize the overall production cost. Moreover, in the framework of process sustainability, social and environmental impacts should include process safety aspects. In this context, the objective of this work is to develop a biodiesel production process based on microalgae and the subsequent estimation of the associated risks, thus contributing to more sustainable and safe processes. The biodiesel biorefinery is optimized, taking into account alternative configurations for algae cultivation and lipid extraction. Algae cultivation options are open ponds and tubular photobioreactors. Regarding lipid extraction, dewatering and subsequent n-hexane extraction, and combined ethanol/n-hexane extraction are the studied alternatives. Numerical results showed that open ponds and n-hexane extraction provide maximum net present value. However, n-hexane consumption dramatically rises, and industrial hazards have not been considered in the optimization process. To overcome this issue, a preliminary hazard analysis is carried out to identify hazardous materials and operations. Event trees are formulated to derive the frequencies of different accident scenarios, further determining the consequences. The major consequences of accidents involve toxic releases of high quantities of n-hexane. By comparing the proposed alternatives, this work aims to highlight the need to consider not only economic but also safety and environmental objectives in the development of a biodiesel production project.The authors are grateful for the financial support provided by CONICET and the Spanish MICINN under projects CTQ2013-48280-C3-1-R and CTM2014-57833-R. J. Pinedo would also like to thank the financial support provided by “Becas Iberoamérica JPI España 2014”

BAYESIAN-INTEGRATED SYSTEM DYNAMICS MODELLING FOR PRODUCTION LINE RISK ASSESSMENT

Companies, across the globe are concerned with risks that impair their ability to produce quality products at a low cost and deliver them to customers on time. Risk assessment, comprising of both external and internal elements, prepares companies to identify and manage the risks affecting them. Although both external/supply chain and internal/production line risk assessments are necessary, internal risk assessment is often ignored. Internal risk assessment helps companies recognize vulnerable sections of production operations and provide opportunities for risk mitigation. In this research, a novel production line risk assessment methodology is proposed. Traditional simulation techniques fail to capture the complex relationship amongst risk events and the dynamic interaction between risks affecting a production line. Bayesian- integrated System Dynamics modelling can help resolve this limitation. Bayesian Belief Networks (BBN) effectively capture risk relationships and their likelihoods. Integrating BBN with System Dynamics (SD) for modelling production lines help capture the impact of risk events on a production line as well as the dynamic interaction between those risks and production line variables. The proposed methodology is applied to an industrial case study for validation and to discern research and practical implications

Assessment of shop floor layouts in the context of process plans with alternatives

Paper aims: The paper seeks to compare the performance of three layouts in a make to order (MTO) production system with high product variability. Originality: No previous work sought to compare job shop, cellular and virtual cell layouts in an MTO system with high product variability, with just 21 resources, a low amount. The analysis considered models with the same capacities and demand for the three layouts. Research method: The complete factorial design and ANOVA were used with simulation. The main effects plots of the control factors for response variables were obtained (e.g. throughput, lead time, and resource utilization). Main findings: The virtual cell layout had results similar to the job shop, but achieved better outcomes compared with the traditional cell. Implications for theory and practice: The knowledge gap regarding virtual cells signals the importance of this topic, as well as the possibilities not yet investigated about it in manufacturing companies.</br

A Mathematical Programming Model for Optimal Layout Considering Quantitative Risk Analysis

Safety and performance are important factors in the design and operation of chemical plants. This paper describes the formulation of a mixed integer nonlinear programming model for the optimization of plant layout with safety considerations. The model considers a quantitative risk analysis to take safety into account, and a bowtie analysis is used to identify possible catastrophic outcomes. These effects are quantified through consequence analyses and probit models. The model allows the location of facilities at any available point, an advantage over grid-based models. Two case studies are solved to show the applicability of the proposed approach.</p

Probabilistic Risk Assessment Tool Applied in Facility Layout Optimization

The severity of several chemical incidents occurred in the recent past has been attributed to improper layout arrangement or proximity of a chemical facility to a densely populated area although this is not a new problem. To address this problem, researchers have been considering not just economic efficacy but also safety features in layout optimization. Therefore, there is still a need for a comprehensive risk assessment methodology in combination with the layout optimization formulation. Moreover, risk probability distributions should be employed to enhance understanding of overall risks and to support decision making during the design phase. The objective of this study is to incorporate a probabilistic risk assessment into the design optimization formulation. The methodology was divided in three main parts. First, a risk assessment program has been developed in MATLAB to estimate risks associated with human life losses and structural damage in a chemical plant. Analytical models for fire and explosion scenarios and toxic chemical releases were included in the program. Monte Carlo simulation was then employed to propagate uncertainties attributed to environemtal conditions and release paramenters. The proposed program generates risk maps and risk distributions at a particular point of interest in a timely manner. Second, domino effect concepts have been included in the resulting program to obtain minimal separation distances between process units necessary to prevent escalation events. These distances vary according the targeted unit type, escalation vector (overpressure or fire impigement) and the risk acceptability criteria. In the last stage, risk maps and safety distances are included in a mixed-integer linear programming (MILP) for layout optimization. The objective function is set to minimize the total capital cost associated with structural damage risk, fatality risk, pipeline interconnection, and protective devices. Individual risk criteria was applied as an additional constraint for high occupancy buildings, meaning that the overall risk for buildings such as control room or lab may not exceed this criterion. The proposed methodology has been demonstrated through a case study. It enhanced flexibility during the layout arrangement allowing the user not just include site-specific data but also the risk acceptance criteria, which reflects the company’s safety culture

Reducción de las emisiones de gases con efecto invernadero (GEIs) en el sector energético mediante tecnologías no convencionales

Históricamente, en la provincia de Santa Fe las demandas de electricidad se satisfacen importando energía generada en otras provincias ya que carece de una matriz energética propia. Se conoce que en Argentina el 52 % de la electricidad se produce en centrales térmicas, que funcionan a gas o diesel; el 43 % en usinas hidroeléctricas, y apenas el 4 % es energía nuclear. A partir del año 2003 las demandas eléctricas en la mayoría de las provincias, incluyendo Santa Fe, se incrementaron fuertemente como consecuencia del crecimiento económico experimentado en diferentes sectores productivos tales como el agro, la construcción y la industria. Esto obligó tanto al gobierno nacional como provincial a impulsar un nuevo plan estratégico con el principal objetivo de aumentar la producción de electricidad y así poder reducir los efectos negativos de la crisis energética que afecta a todo el territorio nacional. A pesar de que las centrales de ciclo combinado operan con gas natural y en consecuencia son las que menos contaminan respecto a plantas que operan con carbón, requieren que los gases de combustión generados deban ser tratados necesariamente antes de ser emitidos al ambiente. La corriente de gases exhaustos contiene uno de los principales responsables del calentamiento global, el CO2. Diferentes estudios revelan que para las próximas décadas la concentración de CO2 en el ambiente aumentaría a ritmos más acelerados en caso que no se adopten las medidas y acciones necesarias tendientes a disminuir dichas emisiones. De este modo resulta evidente la imperiosa necesidad de investigar y proponer soluciones efectivas para reducir las emisiones de gases con efecto invernadero. Algunas de las acciones tendientes a reducir las emisiones de CO2 procedentes de la combustión de combustibles fósiles para la producción de energía, debieran apuntar a: 1) uso racional de la energía generada (aumento de la eficiencia en los procesos de conversión), 2) utilizar combustibles que tengan menores emisiones (energías renovables, gas natural), 3) captura y almacenamiento del CO2 procedente de la combustión. En este sentido, esta tesis se enmarca en el punto 3) ya que se propone investigar y desarrollar procesos eficientes para tratar las emisiones generadas en las plantas de producción de energía eléctrica que contribuyen al efecto invernadero, en especial el CO2.Fil: Arias, Ana Marisa. UTN. FRRo. CAIMI; ArgentinaPeer Reviewe