Risk analysis of LPG tanks at the wildland-urban interface

In areas of wildland-urban interface (WUI), especially residential developments, it is very common to see liquefied petroleum gas (LPG) tanks, particularly with a higher ratio of propane, in surface installations serving homes. The most common tanks are between 1 and 5 m3 of capacity, but smaller ones of less than 1 m3 are more frequent. In case of accident, installations may be subject to fires and explosions, especially in those circumstances where legal and normative requirements allow very close exposure to flames from vegetable fuel near LPG tanks. In this project, it is intended to do a comprehensive diagnosis of the problem, addressing the compilation of information on real risk scenarios in historical fires. First, a preliminary presentation of the properties and characteristics of liquefied petroleum gas will be exposed. Its physical and chemical properties, production methodology, pressure and temperature diagrams and important considerations will be defined when using this type of substances in a storage tank of a certain volume. Next, a review of the situation of the existence of LPG tanks in the urban forest interfaces will be exposed. In this case, the main accidents caused by problems with the storage of LPG will be analyzed taking into account the relevance of BLEVE events in this type of incidents. To do this, the main scenarios that could take place in the event of a fire will be presented. Next, the existing legislation on the storage of LPG in these environments in some Mediterranean countries will be studied. In order to develop a comprehensive analysis, the main safety measures and distances will be considered, as well as the awareness of the possibility of vegetation material in the vicinity of LPG storage tanks, which is the main problem that will arise in a possible BLEVE scenario in case of fire. To finalize and facilitate understanding, a comparative table will be included with the aim of visualizing the main advantages and legislative deficiencies between the different countries. Following, the state of the art in terms of modelling LPG accidents at the WUI will be reviewed. Trying to simulate and predict this type of scenarios, it will see the models normally chosen to obtain the tolerable values selected and the answers obtained in each case. Finally, several fire scenarios will be simulated by means of a CFD tool (FDS, Fire Dynamics Simulator). In these simulations, the wind velocity and the distance of the combustible vegetal mass to the tank will be controlled in a WUI fire in which there is a tank of fixed dimensions. The temperature and the heat flow in each of the scenarios will be obtained, and the differences among the location of the sensors and the characteristics of the scenario will be analyzed. As a conclusion, it has been observed that there is a great amount of variables that are not contemplated by the regulatory organisms and that the existing legislation does not guarantee the safety of the population in this type of environment. From the simulations results, variables as temperature should be studied for further characterizations

WUI state of the art and regulatory needs in Europe

The document summarizes the state of the art of the regulationsrelevant to WUI in Europe, providing an organized set of references to the specific regulatory documents. It is focused on three main relevant topics: i) fuel-reduced fringes; ii) Building codes and standards; iii)Wildland-Industrial Interface. Current regulations are analysed and compared, leading to the identification of important needs and limitations of the current European regulatory frameworkPreprin

수소 생산 및 수송시스템의 안전한 디자인 및 관리 설계

학위논문 (박사) -- 서울대학교 대학원 : 공과대학 화학생물공학부(에너지환경 화학융합기술전공), 2020. 8. 이원보.International demand for hydrogen is increasing. In particular, after the spread of electric vehicles, hydrogen has been connected not only with chemical plants, but also with peoples living life. In this paper, the safe design of a hydrogen refueling station for electronic vehicle and the prediction of the corrosion damage of a pipe defect for the safe management of a hydrogen underground buried pipe is studied. First, the safe design of a hydrogen refueling station targets a process that produces hydrogen from natural gas-derived material, which is known to be the most economical. This is a comparison of three processes: the first is to load hydrogen produced from the outside of the station carried by a high-pressure trailer, and then transform its pressure to meet the demand. The second is to produce hydrogen from gaseous NG(natural gas) through steam reforming reaction, and the last is the process of producing hydrogen by steam reforming reaction through LPG. All three processes is found to exceed tolerable risk levels in areas with some population density under currently known process conditions. Therefore, it is possible to safely design the process by changing the conditions of the process units that most affect the risk to mitigate the risk, or lower the frequency of failure event occurring by constructing additional firewalls. On the other hand, off-site pipelines placed to transport the produced hydrogen going out of the hydrogen station or the incoming hydrogen from the outside are mainly installed in a buried form. Buried piping is an inevitable structure for the utilization of the ground area, but it is difficult to check the condition frequently due to the limitations of drilling costs and human resources to directly check the condition of the piping. Therefore, more attention should be paid to safety management. In particular, buried piping accidents in areas close to the population, such as Kaohsiung in Taiwan or San Bruno in the United States, can cause personal injury, so evaluate and predict whether the risk or reliability of piping is safe and secure in the future. It is important to do. There have been many studies predicting the defect depth distribution of pipes due to external corrosion. Predictive modeling of the previous papers were well predicted defect depths measured in the soil environments. However, the external corrosion of piping is affected by various environmental factors, so a well-made model may be inaccurate in other environments. This is because a large amount of data is required and it is generally difficult to apply to changing soils. To overcome this, the Adaptive Bayesian methodology is needed. Predicting Defect Depth well can be said to have established a model for how quickly the defect depth is growing. Defect Depth Growth rate model, that is, prediction model for External Corrosion rate, has also been studied. Like Defect Depth, since it is affected by various environmental variables, the Adaptive model is effective for general prediction. Therefore, through this, it was possible to study a more accurate prediction model of the defect depth for the safe design of the hydrogen filling station and the reliability measurement of the pipe that transports hydrogen to the outside of the filling station. It is a demand for a more careful and safe design for the hydrogen charging station in the vicinity of a person, and it is expected that through the above study, a safe hydrogen storage will be installed and managed.수소에 대한 국제 수요가 점차 증가하고 있다. 특히 전기자동차의 보급 이후, 수소는 화학플랜트에서 뿐만 아니라, 도시에서 있는 사람들의 생활권과도 맞닿아 있다. 이 논문에서는 전기자동차에 수소를 공급받기 위한 수소충전소의 안전한 설계와 해당 수소충전소의 외부로, 혹은 외부에서 수소가 이송될 경우 이용하게 될 수소 지하매설배관의 안전한 관리를 위한 배관결함의 손상도 예측을 연구하였다. 먼저 수소충전소에 대한 안전한 설계는 수소를 가장 경제적으로 생산할 수 있다고 알려진 천연가스로부터 생산하는 공정을 대상으로 한다. 이는 3가지 공정을 비교할 수 있는데, 첫번째는 외부에서 생산된 수소를 고압 트레일러로 싣고 온 후, 수요에 맞게 변압하는 공정이고, 두번째는 기체상태의 NG에서 수소를 Steam Reforming Reaction으로 생산하는 공정, 마지막으로 LPG에서 수소를 Steam Reforming하여 생산하는 공정이다. 세 공정 모두 현재 알려진 공정 조건에서는 인구밀도가 어느 정도 있는 지역에서 모두 Tolerable한 위험도 수준을 넘어서는 것으로 나타났다. 따라서 위험도에 가장 많이 영향을 주는 공정 유닛들의 조건들을 조금씩 바꿔가며 위험도를 낮추는 공정 수정을 하여 안전한 공정설계를 할 수 있다. 한편, 수소충전소 외부로 나가는 생산된 수소, 혹은 외부에서 들어오는 수소를 이송하기 위해 놓여지는Off-site 파이프라인들은 주로 매설된 형태로 설치가 된다. 매설배관은 지상면적의 활용을 위해 필연적인 구조물이지만, 배관 상태를 직접 확인하기 위한 굴착비용 및 인적 자원의 한계 등으로 자주 상태를 확인하기 힘들다. 따라서 안전관리에 더욱 유의하여야 한다. 특히 대만의 가오슝(Kaohsiung)이나 미국의 산 브루노(San Bruno) 사고처럼 인구 밀접 지역에서의 매설배관사고는 인명피해를 유발할 수 있어, 현재 및 향후에 배관의 위험도나 신뢰도가 안전한 수준인지 평가하고 예측하는 것이 중요하다. 외부부식에 따른 배관의 Defect Depth 분포를 예측하는 연구들이 많이 있어왔다. 선행 논문들의 예측 모델링들은 해당 토양환경들에서 직접 측정한 Defect Depth들을 잘 예측한 모델들이었다. 하지만 배관의 외부부식은 여러가지의 환경요소에 영향을 받고, 따라서 잘 만들어진 모델도 다른 환경에서는 부정확할 수 있다. 대량의 데이터가 필요하고, 변화하는 토양에 일반적으로 적용하기 힘들기 때문이다. 이를 극복하기 위해 Adaptive Bayesian 방법론이 필요하다. Defect Depth를 잘 예측한다는 것은 defect depth가 얼마나 빨리 성장하고 있는지에 대한 모델을 잘 세웠다고도 할 수 있다. Defect Depth Growth rate 모델, 즉 External Corrosion rate에 대한 예측모델 역시 많은 연구가 있어왔다. Defect Depth와 마찬가지로 여러 환경변수의 영향을 받으므로, 이 역시 일반적인 예측을 위해 Adaptive 모델이 효과적이었다. 따라서 이를 통해 수소 충전소의 안전한 설계 및 충전소 외부로 수소를 이송하는 배관의 신뢰도 측정을 위한 Defect Depth의 보다 정확한 예측모델을 연구할 수 있었다. 사람이 인접한 곳의 수소 충전소를 대상으로 하여, 더욱 신중하고, 안전한 설계가 요구되는 수요처이며, 위 연구를 통해 안전한 수소 저장소 설치 및 관리가 될 것을 기대한다.Chapter1. Introduction 1 1.1. Research motivation 1 Chapter2. Safe design for onsite hydrogen refueling station 5 2.1. Background 5 2.2. Process description 9 2.2.1. Hydrogen production process modeling 9 2.3. Quantitative risk assessment procedure 47 2.4. Layout of the hydrogen refueling station 50 2.5. Result and discussion 52 2.5.1. Risk assessment result before process modification 52 2.5.1. Proposed process modification for risk mitigation 70 2.6. Conclusion 74 Chapter3. Adaptive approach for estimation of pipeline corrosion defects via Bayesian inference 75 3.1. Introduction 75 3.2. Adaptive estimation of corrosion defect depth 81 3.2.1. Time-dependent GEV distribution for corrosion defect depth distribution 81 3.2.2. Adaptive estimation framework using Bayesian inference 84 3.3. Implementation 89 3.4. Visualization and discussion 93 3.4.1. Case 1 Direct inspection 93 3.4.1. Case 2 indirect inspection 96 3.4.1. Case 3 sudden changes in hidden depth distribution 100 3.5. Conclusion 108 Chapter4. Concluding remarks 110 Reference 112Docto

Fuel cell systems for marine applications

The aim of this work is the assessment of the most suitable hydrogen solution for ship applications and the definition of the role of hydrogen as alternative fuel for shipping. The importance of the \u201cHydrogen Technologies\u201d for ships comes from the most important social challenge that is driving innovation in the shipping sector: Environmental Challenge. The PhD research project encountered important development both from the industrial and the academic side that brought to the construction of a joint laboratory between Fincantieri and the Polytechnic School of the University of Genoa, the: HI-SEA laboratory, dedicated to the study of fuel cell system for marine application. Moreover the simulation modelling and experimental results developed during the PhD research on the PEM fuel cell and MH hydrogen storage systems, found an application in the nautical sector. The former brought to a patent and the creation of a dedicated start-up company named H2Boat, that was recognised as University spin-off. The first part of the study define the role of hydrogen as alternative energy vector (fuel) for marine application, analysing the complex context in which it is supposed to be used. In part 2.1 a detailed assessment of the characteristics of different alternative fuels have been conducted. The complexity of work brought to the construction of comparative models, descripted in part 2.2 that have been used to analyse the characteristic of various alternative solution. An analysis of the PEM FCS state of the art is presented in part 2.3 together with the definition of FCS design for marine application in part 2.4. The study of the hydrogen technologies considered also the definition of simulation models of fuel cell systems and metal hydride hydrogen storage system 3.2. The former has also been assessed towards experimental tests, presented in part 3.3. The models have been used to develop larger laboratory, to define correct operative parameters and FCS design. Finally a number of application developed during the PhD study are proposed in part 4 to show the goal of the research that is still under development

DESIGN AND DEVELOPMENT OF A SMART ADVISORY SYSTEM FOR HAZARDOUS MATERIALS TRANSPORTATION RISK ANALYSIS VIA QUANTITATIVE APPROACHES

Safe transportation of hazardous materials is critical as it has a high potential of catastrophic accidents depending on the amount of transported product, its hazardous characteristics and the environmental conditions. Consequently, an efficient, smart and reliable intervention is essential to enhance prediction on the impacts of transportation hazards. Although various risk assessment techniques have been used in industry and regulatory bodies, they were developed for evaluating risk of hazardous materials for fixed installation cases instead of moving risk sources. This study applies the Transportation Risk Analysis (TRA), which is an extension of a well-known Quantitative Risk Analysis (QRA) technique in developing and design a Smart Advisory Systems (SAS), to determine the safest routes for transportation of hazardous materials according to Malaysia scenario

An economic evaluation of the potential for distributed energy in Australia

Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) recently completed a major study investigating the value of distributed energy (DE; collectively demand management, energy efficiency and distributed generation) technologies for reducing greenhouse gas emissions from Australia’s energy sector (CSIRO, 2009). This comprehensive report covered potential economic, environmental, technical, social, policy and regulatory impacts that could result from the wide scale adoption of these technologies. In this paper we highlight the economic findings from the study. Partial Equilibrium modeling of the stationary and transport sectors found that Australia could achieve a present value welfare gain of around $130 billion when operating under a 450 ppm carbon reduction trajectory through to 2050. Modeling also suggests that reduced volatility in the spot market could decrease average prices by up to 12% in 2030 and 65% in 2050 by using local resources to better cater for an evolving supply-demand imbalance. Further modeling suggests that even a small amount of distributed generation located within a distribution network has the potential to significantly alter electricity prices by changing the merit order of dispatch in an electricity spot market. Changes to the dispatch relative to a base case can have both positive and negative effects on network losses.Distributed energy; Economic modeling; Carbon price; Electricity markets

Renewable Energy and Other Strategies for Mitigating the Energy Crisis in Nepal

The overarching aim of this research is to carefully review Nepal’s energy scenario from the technical and socio-economic perspective in order to determine the optimal near-term as well as long-term strategies to overcome the energy crisis. Renewable energy sources are pivotal to this research due to the abundant availability of these resources in Nepal. The long-term energy supply and demand forecast for Nepal over the next 30 years was obtained in Long-Range Energy Planning (LEAP) software. Other quantitative results were obtained using software packages, including PVsyst, Meteo, and HOMER. In many other cases, energy data collected from open literature,government and regulator reports were analysed. There are also several case studies considered in the thesis. The PV rooftop energy systems for Nepalese town and rural households can minimise the energy trade deficit with neighbouring India, enhance energy security, and improve local employment opportunities as well as improve utilisation of the local resources. In particular, a 3kW PV rooftop system was designed and simulated in MATLAB/Simulink, and the corresponding PV and IV curves were obtained, including analysing the effects of environmental temperature and solar irradiation. The design was followed by techno-economic feasibility, assuming typical households inthe Kathmandu valley. The study outcome is that the PV system for a residential building in Kathmandu is economically feasible, and it can provide nearly 6,000 kWh/year of energy. The potential energy efficiency improvements in the cement industry were studied using data collected directly at one of the major cement plants in Nepal. The cement production processes are very energy-intensive, and they have not changed for years. Since the energy costs in Nepal are abnormally high, they represent over half of the cement production costs. It creates substantial pressure to conserve energy and materials while reducing the carbon footprint. Other important factors that must be considered apart from energy issues are production efficiency and sustainability, and how to exploit innovations and encourage investments. The chaotic energy situation in Nepal is exacerbated by rather significant electricity distribution losses and frequent cases of electricity theft. These two issues are significant contributors to a widening gap between energy supply and demand. iv. Other such issues include overpriced and delayed hydropower projects, insufficient and outdated infrastructure, lack of energy conservation, deficient energy management, inadequately low efficiency of equipment, unsustainable energy pricing strategies, indecisive energy market regulations, reliance on energy imports, and especially inadequate exploitation of vast amounts of renewable energy resources. All these factors are also adversely affecting the geopolitical, environmental, and socioeconomic situation in Nepal. The developments in the energy sector in Nepal are also discussed in light of the relevant energy policies which have been adopted by the government over the past two decades. The results presented in the thesis can be used by the government regulators and energy policy planners, and possibly also by the public and private energy companies. It should be noted that the findings and observations in the thesis are also applicable to other countries with a similar development status and geography as Nepal

A new framework to estimate the probability of fire following earthquake

Fire following earthquake has been recognized as a very significant risk in the past decade. Several studies have been performed by researchers to develop analytical and experimental methods to assess the economic and life losses due to fire after an earthquake event. While the outcome of these efforts has resulted in significant advances, an accurate and simplified framework to be utilized by practicing engineers is still lacking. In this paper, a new methodology to predict the probability to have fire following a seismic event considering the building seismic damage is proposed. Earthquake was considered as the main hazard, whereas blast and fire were assumed as a cascading hazards. Bayesian approach was used to estimate conditional probability of fire caused by an earthquake. A hospital building has been assumed as case study, while a LPG tank located nearby the structure has been considered as potential source of blast and ignition. A physical-based simulation was used to evaluate intra-structure ignition probability due to leakage and/or breaks of the gas pipelines. Several parameters were considered to model the occurrence of intra-structure ignitions such as structural and non-structural damage, earthquake intensity, buildings geometry and occupancy and earthquake scenario time. proposed framework is considered a significant step to accurately predict fire risk following a seismic event with affordable time and it can be an alternative solution to the statistical ignition model currently being used in many fire following hazard methods

Coal fuel gas cleaning by non-thermal pulsed corona discharge plasma and “reach” regulation compatibility assessemnt for trace elements extraction from gasification ash

Dissertação de mestrado, Inovação Quimica e Regulamentação, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016Atmospheric small-scaled fixed-bed gasifiers fed with cheap low rank sub-bituminous coal produces syngas (CO and H2) with high tar content, which is one of the impurities produced along the main syngas from coal gasifications. This organic impurity with high molecular weight hydrocarbons is of interest as they polymerize or condense to more complex structucres throughout the involved process pipers or heat exchangers, leading to fouling and attrition problems, which eventually leads to lose of overall plant efficiency and increased operation costs. To avoid such event, either expensive non-tar forming coal (semi-Anthracite or Anthracite) must be used or an effective tar removal unit integration in the overall process should be made. Plasma is the fourth state of matter and it contains free radical, ions and excited molecules and they create a highly reactive atmosphere as these reactive species carry enough energy to initiate tar decomposition reactions. Non-thermal plasmas are already successfully utilized in air pollution control for the VOC removal. Within the non-thermal pulsed corona discharge plasma scope, Technical university of Eindhoven (TU/e) studied biomass tar reforming (naphthalene as the tar model) and various syngas compositions were tested to study their impact on tar removal process. Furthermore, non-thermal pulsed corona discharge plasma is found to be effective in tar reforming and is created by supplying electricity and nitrogen gas to the plasma reactor. Created plasma dissociates the CO2 components in the syngas into CO and O radicals, which the unstable reactive O radicals oxidize tars into light hydrocarbons (CH4). 50% nitrogen content in the syngas due to plasma requirement limits its usage only as fuel gas for heating or electricity generation. After determining utilizing of plasma together with atmospheric fixed-bed gasifier is technologically possible, the demand for it in fuel gas application to generate heat is researched. The research involved carefully looking at energy policy of that chosen particular country and their main source of energies. According to the International Energy Agency’s 2015 statistics, China and India are placed largest coal consumers in the non-OECD countries ranking. It was estimated that China currently needs over 8000 fixed-bed gasifier (8000 plasmas) to meet the industrial heat demand. Assuming a similar development in India, in total 2000 fixed-bed-gasifiers will be needed in the next years. In the researched countries, current alternative method to generate heat instead of Natural gas or LPG is fuel gas via coal gasification. Non-tar forming quality coal are gasified, but they are either expensive due to the high demand and are not widely available. Syngas from this case is cleaned through electrostatic precipitator light tar collectors (if present) before utilizing it. These fuel gas-cleaning methods are to remove very small amount of light tars (if present) and dusts. It is a common practice in developing countries to produce fuel gas via coal gasification for the puspose of heat and electricity generation. It was found that this method is cost effective than using natural gas or LPG. Furthermore, it was found that fuel gas generation via plasma-involved case were even more cost effective than the current state of art case by at least 10%. The fuel gas production cost via plasma involved proposing configuration is competitive over the fuel gas production cost from the current state of art. In addition to cost benefits, plasma cleaned fuel gas production approach allows utilizing of low rank coal and does not utilize water, hence fresh water consumption and pollution is prevented. Abundantly available coal ashes are potential untapped resource for trace elements (TE). In 2014, the European union member states (EU-28) had consumed 285 million tones of hard coal and based on the world trace elements average in world coal, the available TE for extraction exceeds 1 tonne per year. Therefore, TE extraction from available coal ashes in EU-28 is subject to REACH regulation. However, there is no entry on ECHA database for such process. The entries at ECHA database regarding coal ash are only for the utilization for construction materials purpose. Lack of commercially available extraction technology optimized for coal ash, limited understanding of trace elements modes of occurrence, origin, and toxicological data relating to all possible chemical contaminants rising from extraction process are not well understood and are not presently available. More research and development effort must be done in order to obtain these missing information and to perform full chemical characterization of the coal ash to optimize trace elements extraction process for that particular coal and to identify all possible waste streams. Such that, needed toxicological data according to REACH regulation is obtained