Risk Assessment of LNG Storages using LOPA and FTA: An Integrated Approach

PresentationLiquefied Natural Gas (LNG), an economically attractive and environmental friendly fuel is the current energy alternative across the globe. Its market potential and high demand is felt currently in the Indian subcontinent as well. Government and private players are seriously getting into this energy option and establishing many LNG facilities on the west and east coast of India. While establishing in this new energy sector it is vital to identify and analyse the safety hazards likely to affect public and environment. LNG being a flammable chemical, loss of its containment manifests to consequences in terms of fire, explosion and other impacts. There are several methods currently available to carry out the risk analysis of such projects. LOPA is a quick and simple technique applied to determine the risk by estimate consequence frequencies. But application of LOPA becomes constrained when failures are compound and safety systems are integrated. Fault Tree Analysis (FTA) was integrated into LOPA to eliminate this draw back. FTA was used to find out the probability of failure on demand (PFD) of integrated protection layers. This FTA-LOPA integrated approach was used as an effective tool in this work to study hazard potentials and estimate the consequences due to such hazards. Based on the technical specifications provided and description of the work, the LOC scenarios are identified in the facility from the HAZOP study

Quantitative risk assessment of medium-sized floating regasification units using system hierarchical modelling

Currently there are no sufficiently detailed and specific regulations and guidelines applicable to Floating Regasification Units. In view of the fact that these units are likely to become more popular in the near future, their safety needs to be examined urgently. During the design of the world's first medium-sized floating regasification unit a qualitative risk assessment was carried out. Although the results are useful, they cannot be used for developing rules and regulations directly. For such purposes some detailed quantitative studies are essential. This paper addresses this gap and introduces a hierarchical system modelling method to overcome the problem of the lack of direct statistical accident data of novel systems. The method was implemented in IQRA (integrated quantitative risk assessment), a piece of software developed in-house for quantitative risk assessment. The safety of the floating regasification unit mentioned above was assessed using this software and the results were compared against the results obtained from conventional qualitative and the quantitative risk assessment. It was found that the qualitative risk assessment had a tendency to overestimate the frequency of the accidents but to underestimate their consequence, while the quantitative risk assessment based on the result of the qualitative assessment inherently underestimated both the frequency and the consequence of hazards. The hierarchical modelling was found to be an excellent method of dealing with complex systems with short operational history

Mathematical Modelling of LNG Dispersion Under Various Conditions

The global demand of liquefied natural gas (LNG) has risen rapidly in recent years. A new modelling method, direct CFD simulation method, was developed, due to the risks associated in handling, storage and transport of LNG. This method was shown to accurately model a LNG spill, pool formation and dispersion; and has been used to study the effect of (a) Impoundments, (b) Sea and air temperature and; (c) Sea and air stability

Vertical Structures in the Global Liquefied Natural Gas Market: Vertical Structures in the Global Liquefied Natural Gas Market: Empirical Analyses Based on Recent Developments in Transaction Cost Economics

During the last decade, the global liquefied natural gas (LNG) market altered substantially. Significant investments have been realized, traded volumes increased and contracting structures gained in flexibility. Various governance forms co-exist, including the poles of spot market transactions and vertical integration as well as numerous hybrid forms such as long-term contracts, joint ventures, and strategic partnerships. This dissertation empirically investigates, based on transaction cost economics and recent extensions thereof, which motivations drive companies towards the choice of hierarchical governance forms. First, the likelihood of vertical integration and the impact of inter-organizational trust as a shift parameter accounting for differences in the institutional environment are analyzed. Estimation results confirm transaction cost economics by showing that relationship-specific investments in an uncertain environment drive LNG companies to invest in successive stages along the value chain. Furthermore, the presence of inter-organizational trust increases the likelihood of less hierarchical governance modes. Second, alternative theories of the firm are linked in order to explain the menu of strategic positions recently observed in this dynamic market. Estimation results support the positioning-economizing perspective of the firm. The three strategic choices of target market position, resource profile, and organizational structure are interdependent. Third, the determinants of optimal contract length as a trade-off between the minimization of transaction costs due to repeated bilateral bargaining and the risk of being bound in an inflexible agreement in uncertain environments is discussed. Estimation results show that the presence of high asset specificity results in longer contracts whereas the need for flexibility in today’s LNG market supports shorter agreements. When firms have experience in bilateral trading, contract duration decreases. In addition, countries heavily reliant on natural gas imports via LNG are often willing to forgo some flexibility in favor of supply security. Contracts dedicated to competitive downstream markets on average are shorter than those concluded with customers in non-liberalized importing countries

EU Gas Transmission Network Facilities Review: Inventory, operation and failure modes of the main components of the EU gas system. An information source to gas risk assessments.

This report addresses a review of main EU natural gas transmission network facilities. A review of Liquefied Natural Gas (LNG) regasification terminals, Underground Gas Storage (UGS) facilities, Compressor Stations (CS) and pipelines has been done. Special attention has been paid to identify types, operation modes and main types of failures of these facilities. Reasonable ranges of failure frequencies have also been selected from the available literature. The contents of this report are expected to be relevant as data sources to national and regional Risk Assessments (RA) performed in line with Regulation (EU) 2017/1938 concerning measures to safeguard the security of gas supply.JRC.C.3-Energy Security, Distribution and Market

Dynamic evaluation of risk: From safety indicators to proactive techniques

This contribution presents a short review of dynamic risk evaluation techniques based on human and organizational factors, from the first approaches developing indicators to the aggregation methodologies integrating risk analysis. A methodology for the evaluation and update of expected release frequencies is taken as example of last generation techniques. The methodology aiming to support dynamic risk assessment studies is named TEC2O - Frequency modification methodology based on TEChnical Operational and Organizational factors. The potential of such methodology is described also in terms of support to risk based decision making for Oil&Gas integrated operations

Sustainability and risk management of LNG as a fuel for marine transportation

The use of liquefied natural gas (LNG) as an alternative ship fuel marks a fundamental step towards the reduction of emissions linked to maritime transportation of goods and passengers. Despite the positive safety record of the LNG shipping industry, natural gas is a hazardous substance and safety concerns for its use onboard passenger ships demand a thorough evaluation. This study aims at a comprehensive safety and sustainability assessment of marine LNG technologies, focusing on small-scale applications, seeking to fill the current knowledge gap in this field. An in-depth evaluation of the safety of existing technologies for LNG bunkering and onboard fuel gas supply systems is performed, providing key information about the credible accident scenarios and their expected consequences. The safety criticalities are identified based on the application of specifically developed models for the evaluation of the inherent safety performance of LNG bunkering and propulsion technologies. Another part of the work is dedicated to the development of a computational fluid dynamic (CFD) setup to model the behaviour of cryogenic tanks exposed to accidental hydrocarbon fires, overcoming the limitations of the previous modelling approaches, and providing precise data for further analysis of the tank structural integrity under extreme conditions. Furthermore, a preliminary CFD modelling of LNG fire scenario consequences occurring inside the fuel preparation room of gas-fuelled ships is carried out to evaluate the heat flux received by the ship structure. The obtained results represent a first step towards a wider approach aimed at enhancing the safety of the entire LNG supply for maritime propulsion. Furthermore, these results can make a valuable contribution to support the decision-making process for shipowners and port authorities in the design and safety assessment of such systems, both in port areas and onboard ships, also providing guidance for emergency responders

Facility Siting Study of LNG-FSRU System Based on Quantitative Multi-Hierarchy Framework MADA

This research proposed to establish a quantitative assessment framework for a site selection study of liquefied natural gas (LNG) receiving terminal by considering both chemical process safety and marine transportation safety. The offshore LNG terminal, referred as LNG floating storage unit (FSU) or floating storage and re-gasification unit (FSRU), performs well on both building and operation processes. The LNG FSRU system is a cost-effective and time efficient solution for LNG transferring in the offshore area, and it brings minimal impacts to the surrounding environment as well. This paper proposed an evaluation framework for LNG FSRU system site selection. The evaluation framework was adopted to process a comparison study between two possible locations for LNG offshore FSU/FSRU. This research divided the whole process into three, beginning with the LNG Carrier navigating in the inbound channel, through the berthing operation and ending with the completion of LNG transferring operation. The preferred location is determined by simultaneously evaluating navigation safety, berthing safety and LNG transferring safety objectives based on the quantitative multi-hierarchy framework multi-attribute decision analysis (QMFMADA) method. The maritime safety analysis, including navigational process and berthing process, was simulated by LNG ship simulator DMU V-Dragon 3000A and analyzed by statistical software such as R and JMP. The chemical process safety simulation was employed to LNG transferring events such as connection hose rupture, flange failure by the consequence simulation tool Safeti. Two scenarios, i.e., worst case scenario and maximum credible scenario, were taken into consideration by inputting different data of evaluating parameters. The QMFMADA method transformed the evaluation criteria to one comparable unit, risk utility value, to evaluate the different alternatives. Based on the final value of the simulation, the preferred location can be determined and the mitigation measures were presented accordingly

Sustainable nutrient recovery from animal manure: A review of current best practice technology and the potential for freeze concentration

Current trends of livestock expansion and associated mass production of manure bring a net import of nutrients that have led to a significant excess in many areas. The implementation of an efficient and more economical technology solution to recover and re-use nutrients from raw or digested wastes is essential and will reduce the need for fossil-fuel based fertilizers. From a waste management standpoint, the identification of nutrient recovery technologies is considered one of the main challenges within a circular economy context. Several traditional techniques exist for manure treatment such as, gasification, thermochemical conversion, composting, hydrothermal carbonization, and liquefaction. However, these technologies face many challenges related to energy consumption and recovered nutrient quality. In this context, freeze concentration (FC) is an emerging technique that can be applied to recover water and concentrate nutrients from waste liquid effluents. This technology brings advantages such as high concentration factor and low energy usage. However, freeze concentration technology is only semi-industrialised and for most applications remains at the development stage. Many studies have been conducted to design and develop processes and applications that target the improvement of both productivity and efficiency, which makes freeze concentration an attractive research subject to the scientific community. Combination of freeze concentration technology with another technology, such as membranes, to generate a more efficient hybrid process must also be considered. This approach of resource recovery from animal manure would ultimately create a more sustainable and circular economy. This paper evaluates the current state-of-the-art and processing strategies related to the treatment of livestock waste materials and contains an up-to-date and critical review on nutrient-rich effluent valorization technologies; focusing on the latest technological progress to recover nutrients from animal manure and introduces the potential that freeze concentration offers, which has only been marginally explored to date. This work makes a comparative analysis of the different processes in terms of their efficiency, cost, energy consumption, operational management, and the results obtained from both bench and large-scale experiments; making it possible to determine the current best practice procedures for the treatment of animal manure