Showing papers by "Faisal Khan published in 2002"

Inherent safety in offshore oil and gas activities: a review of the present status and future directions

Abstract: Inherent safety is a proactive approach for hazard/risk management during process plant design and operation. It has been proven that, considering the lifetime costs of a process and its operation, an inherently safer approach is a cost-optimal option. Inherent safety can be incorporated at any stage of design and operation; however, its application at the earliest possible stages of process design (such as process selection and conceptual design) yields the best results. Although it is an attractive and cost-effective approach to hazard/risk management, inherent safety has not been used as widely as other techniques such as HAZOP and quantitative risk assessment. There are many reasons responsible for this; key among them are a lack of awareness and the non-availability of a systematic methodology and tools. The inherent safety approach is the best option for hazard/risk management in offshore oil and gas activities. In the past, it has been applied to several aspects of offshore process design and operation. However, its use is still limited. This article attempts to present a complete picture of inherent safety application in offshore oil and gas activities. It discuses the use of available technology for implementation of inherent safety principles in various offshore activities, both current and planned for the future.

GreenPro-I: a risk-based life cycle assessment and decision-making methodology for process plant design

Abstract: In recent years, significant attention and emphasis has been given to cleaner and greener technologies in processes and product manufacturing. This is recognized as a key element in pollution prevention (P2) and development of sustainable strategies. Life cycle assessment (LCA) is a systematic approach that enables implementation of cleaner and greener product and process concepts in industry. In recent times substantial progress has been made in the use of LCA for product evaluation and selection. However, its use in cleaner and greener process design and decision-making has not been explored to a great extent. Process design and decision-making are challenging activities that involve trade-off of conflicting objectives, namely costs, technical feasibility and environmental impacts. These conflicting objectives can be analysed at the early design and decision-making stage by considering the full life cycle of a process or a product. A cleaner and greener process is the one that is cost optimal, technically feasible, and environmentally benign. To obtain these results LCA requires various tools and techniques in a systematic methodology. This paper proposes a holistic and integrated methodology GreenPro-I for process/product design by combining the traditional LCA approach with multi-criteria decision-making methods. This methodology is simple and applicable at the early design stage and is more robust against uncertainty in the data. Application of the methodology has been demonstrated in the paper through a urea production case study.

A criterion for developing credible accident scenarios for risk assessment

Abstract: Maximum credible accident analysis is one of the most widely used concepts in risk assessment of chemical process industries. Central to this concept is the aspect of ‘credibility’ of envisaged accident scenarios. However, thus far the term credibility is mostly treated qualitatively, based on the subjective judgement of the concerned analysts. This causes wide variation in the results of the studies conducted on the same industrial unit by different analysts. This paper presents an attempt to develop a criterion using which credible accident scenarios may be identified from among a large number of possibilities . The credible scenarios thus identified may then be processed for detailed consequence analysis. This would help in reducing the cost of the analysis and prevent undue emphasis on less credible scenarios at the expense of more credible ones.

Quantification of inherent safety aspects of the Dow indices

Abstract: The Dow fire and explosion index (F&EI) and chemical exposure index (CEI) have been successfully implemented in a Visual Basic environment as a tool for the inherent safety assessment of chemical processes. Subprograms were developed to quantify the inherent safety aspects of the Dow indices. These aspects are presented graphically with the indices on the vertical axis and an inherent safety indicator on the horizontal axis. Dow indices of the MIC storage unit involved in the Bhopal disaster were evaluated to quantify the effects of process temperature, pressure and inventory of hazardous materials on the index values. As operating pressure was reduced, the F&EI decreased in accordance with the principles of inherent safety. The change in F&EI due to reduction of inventory was more significant than that resulting from pressure reduction. The results show that the F&EI change, given the same range of the independent variables (quantity of hazardous materials, operating temperature and pressure), is larger when a unit in the process area is evaluated compared to a unit in a storage area (tank farm). Reduction of the inventory of hazardous materials had no direct effect on the CEI for vapor releases, whereas the size of the hole diameter impacted the CEI to a great extent. However, there is a significant change in the CEI as the inventory of materials decreases for liquid releases involving temperatures above their flash and boiling points. Pressure reduction decreases the CEI, whereas temperature reduction leads to an increase in the CEI when these parameters are treated independently.

Design and evaluation of safety measures using a newly proposed methodology “SCAP”

Abstract: An increase in the number of accidents in the process industries and the concomitant damage potential is a cause of concern in many countries. In order to control the alarming risk posed by these industries, the United States government has asked each manufacturing facility to carry out a worst-case disaster study and to develop alternatives to control this high risk. Other developed and developing countries such as Canada and India have taken similar measures. Recently Khan and Abbasi (J. Loss Prevent. Process Ind. (2001a) in press) have proposed a maximum credible accident analysis with a maximum credible accident scenario approach, which scores over a worst-case scenario approach for being realistic and reliable. In another effort, Khan and Abbasi (J. Hazard. Mater. (2001b) in press) have developed an efficient and effective algorithm for probabilistic fault tree analysis. These two approaches have been combined to yield a new methodology for a more realistic, reliable, and efficient safety evaluation and the design of risk control measures. The methodology is named SCAP: Safety, Credible Accident, Probabilistic fault tree analysis. The methodology is comprised of four steps of which the last step is a feedback loop. This paper recapitulates this methodology and demonstrates its application to ethylene oxide (EO) plants. The application of SCAP to EO plants identifies five units as risky and needing more safety measures. Further, this study recommends safety measures and demonstrates through SCAP that their implementation lower the risk to an acceptable level.

Effective environmental management through life cycle assessment

Abstract: Unplanned and unsustainable development (particularly rapid industrialisation) has placed great pressure in every dimension of the environment (air, water, soil, health, etc.). The resulting disturbance in the natural ecological balance is a serious concern. Sustainable development is the need of the hour; it can only be achieved through effective environmental management. Environmental management will become indispensable in the future as regulatory restrictions tighten and public expectations of environmental performance increase. The day is not far away when a customer will prefer to buy products produced by an environmentally committed organisation. In short, the environmental commitment of an organisation will become a market strategy. Environmental management is a set of actions based on a structured methodology to ensure that an organisation is committed to the environment and that the production process has minimal/no adverse affect on it. This article emphasises environmental management in the real engineering sense of the term, and discusses how to develop an effective environmental management system through life cycle assessment. It further demonstrates through a real life case study how an industry has achieved landmark success in managing its environment, production, as well as winning the good faith of society.

Modelling of Buckingham Canal water quality.

Abstract: The paper presents a case study of the modelling of the water quality of a canal situated in a petrochemical industrial complex, which receives wastewaters from Madras Refineries Limited (MRL), and Madras Fertilizers Limited (MFL). The canal - well known Buckingham Canal which passes through Chennai (Madras), India - has been modelled using the software QUAL2E-UNCAS. After testing and validation of the model, simulations have been carried out. The exercise enables forecasting the impacts of different seasons, base flows, and waste water inputs on the water quality of the Buckingham Canal. It also enables development of water management strategies.

An inherent safety framework for dust explosion prevention and mitigation

Abstract: Inherent safety is a proactive approach for hazard/risk management during process plant design and operation. Although it offers an attractive and cost-effective methodology for risk reduction, inherent safety has not been used as widely as engineered (add-on) and procedural measures. The current work is an attempt to bring the use of inherent safety principles into the mainstream of process safety management, with particular emphasis on dust explosion prevention and mitigation. Existing frameworks for selecting prevention and protection measures are reviewed. Examples are given of inherent, engineered and procedural safeguards identified in these schemes. A framework is proposed for dust explosion prevention and mitigation based on the hierarchy of examining inherently safer options first (i.e. before add-on and procedural safeguards).

Design of greenbelt for an industrial complex based on mathematical modelling.

Abstract: Greenbelt is a strip of vegetation for which species of trees and shrubs are scientifically chosen and planted to serve a designated purpose such as control of wind erosion, of dust, of noise etc. In the context of air pollution attenuation, greenbelts must be developed around a source of air pollutant in a manner so as to effectively reduce the pollution caused by that source. Design of effective greenbelts involves consideration of meteorological, physico-chemical, biological, and horticultural aspects relevant to pollutant source and the area where greenbelt has to be established. These authors have recently developed mathematical models for effective design of greenbelts. This paper presents an overview of the methodology based on the models, and describes a case study in which the methodology has been applied to design a greenbelt for a real-life situation.

Clean up contaminated sites

Abstract: Natural attenuation is the reduction of mass, mobility or toxicity of site contaminants by the naturally occurring processes of biodegradation, dilution, dispersion, adsorption, volatilization and chemical stabilization. It is a cost-effective and feasible site-remediation option if contaminant reduction occurs within a reasonable time-frame without causing any detrimental effects to human health and local ecological systems. To comply with environmental regulations, a systematic procedure is needed to monitor the extent of contamination, the associated risk, and the effectiveness of natural attenuation. Existing procedures suffer from shortcomings related to duration and cost. This article presents a new modular methodology for risk-based monitored natural attenuation. This approach has been used successfully to evaluate previous site-remediation projects and has been found to save both time and money.