Fire And Explosion Models

The surface emissive power (SEP) is the heat flux due to heat radiation at surface area. It can be calculated with the Stefan-Bolzmann-equation 230 SEP is surface emissive power, in W m2 e is emittance factor (emissivity) t is constant of Stefan-Bolzmann ( 5.6703.10-8 W m2K4) Tf is radiator surface temp of the flame (K) The heat flux q at certain distance from the fire, which is experienced by the receiver per unit area, can be calculated by is heat flux at a certain distance, W m2 is view...

Bibliography On Biogas

1 AIChE CCPS Daw's chemical exposure index guide CEP technical manual, American Institute of Chemical Engineers AIChE , New York, 1994. 2 AIChE CCPS Guidelines for chemical process quantitative risk analysis, Second Edition, American Institute of Chemical Engineers AIChE , New York, 2000 3 AIChE CCPS Guidelines for chemical transportation risk analysis American Institute of Chemical Engineers AIChE , New York, 1995. 4 AIChE CCPS Guidelines for Evaluating the Characteristics of Vapor Cloud...

Consequences Modelling Results

The consequence analyses that are passed to the impact calculations give the shapes and sizes of the different effect zones. For some impacts the results may be independent of weather conditions. For other impact there is a separate result for each weather condition. For example, the effect zone shape of BLEVE fireball is a circle and is weather independent. Therefore, the effect zone is centred at the release point. This section presents the consequence modelling results for the hydrogen study...

The Hydrogen Scenarios Considered

Germany, the world fifth largest consumer of energy, depends heavily on energy import to meet energy demand. Nearly all petroleum and about 80 of natural gas used are imported 176 . About one fourth of final energy consumption of the country 1990-1999 is demanded by industry. The traffic sector has nearly 30 followed by households with 28.5 . Small businesses hold a share of 16 of the final energy consumption. The military is below one percent. It is also shown that the energy consumption of...

Risk Presentation

Alarp Meaning

Two risk measures were considered to present the risk associated with the hydrogen study objects, i.e. individual and societal risk F-N curve , as described in section 4.6.1. The IR of the hydrogen study objects are presented as risk profiles. To create a risk profile, the triplets of the overall risk in Table 5-32 must be transformed into risk profiles and plotted by means of the CCDF, as described in section 4.6.2.2. The risk is expressed as individual risk depending on distance from the...

High Pressure Water Electrolysis

Through a special material choice and optimization, high pressure water electrolysis allows the generation of hydrogen at pressures of up to 5 MPa. The processes under development attempt to find an appropriate capacity optimization that will also allow a problem free connection of the electrolyser with a fluctuating current supply e.g. Wind or PV connection for isolated plants . A development work to mention is that being carried out by GHW Gesellschaft f r Hochleistungswasserelektrolyse for...

Hydrogen Energy Cycle

Underground Hydrogen Storage

Conceptually, the purpose of a hydrogen energy economy can be categorized as the 1 production, 2 storage and transport, and 3 use of hydrogen. Some applications may involve all three categories. Figure 2.3 illustrates a structure of an energy supply system for an industrialized country e.g. Germany with import clean hydrogen i.e. hydrogen energy economy , proposed by Winter and Nitsch 200 . In the system, hydrogen is fed into the supply system in a similar way as today natural gas. In the case...

Fire and Explosions

PHAST automatically generates the existing fires and explosions models as long as the material is flammable. This section presents a summary of the consequence calculation results for the study objects presented both in the form of tables and graphs. Each of the models is presented by two graphs and a table, each of which shows thermal or overpressure impacts from different study objects. The first graph shows thermal radiation or peak overpressure levels vs downwind distances, and the second...

Determination of Minimal Cut Sets by Analytical Methods

Minimal Cut Sets Example

The analytical method uses Boolean algebra operations in order to transform a fault tree into minimal cut sets. In contrast to the simulation methods, it does not require information on component failure behaviour 242 . This is only needed for calculating the failure probability of the system. It finds all minimal cut sets of a system. In order to avoid difficulties with computer capacity, a cut-off criterion must be applied 242 . Basically two approaches may be used in the method, i.e. the...

Households Scenarios

Fermentation Market Growth

The Federal Republic of Germany is a densely populated country with approximately 83 million inhabitants 2003 , which corresponds to a population density of 230 persons per square kilometres. The Federal Republic of Germany is characterized already today as an industrialized country with having a low number of young people. The population development shows that in a few years there will be more people aged 65 years than aged 15 years or less. Low numbers of births and a declining propensity to...

Partial Oxidation of Heavy

Steam Reforming Flow Sheet Study

As steam reforming is not applicable to convert hydrocarbons heavier than naphtha to hydrogen, partial oxidation of heavier feedstock is used to produce hydrogen. A simplified flow diagram of the process is shown in Figure B.2. The process basically proceeds at moderately high pressure with or without a catalyst, depending on the raw material and process selected. The catalytic partial oxidation which occurs at 600oC, uses feedstock ranging from methane to naphtha. The non-catalytic partial...

Fig Steam reforming process [ Hydrogen Storage and Transportation

Adiabatic Compression Filling Tanks

2.3.2.1 Compression and Liquefaction Packaging Hydrogen still requires further preparation according to the demands of the intended end use. Firstly, cleaning of the hydrogen is required in order to ensure that the required quality is met. Following this it must be compressed, whereby the pressure level is dependent on either the end application or the intermediate storage method. Alternatively, liquefaction may be the reasonable option if transport over long distances is required or if the end...

Outline Of The Study Objects

Study Fermentation

A key of precondition for the realisation of a hydrogen economy is the development of a hydrogen infrastructure which, by definition, includes the systems needed to produce hydrogen, to store it, and to deliver it to users. As discussed in Section 2.3, in order to realize the hydrogen energy economy in Germany, the required clean hydrogen may be imported from other countries 200, 201,168 . For example, the Euro-Quebec Hydro-Hydrogen Pilot Project, 1989-2001 EQHHPP considered to import hydrogen...

Hydrogen Energetic Applications

Gasoline Hydrogen Flame Speed

Hydrogen has many potential energy uses, including powering non-polluting vehicles, heating homes, and fueling aircraft. Energetic applications of hydrogen can be classified into two main categories, i.e. direct combustion e.g. internal combustion engine and fuel cells. An internal combustion engine ICE transforms chemical energy contained in a fuel into mechanical energy through combustion in a piston or rotary engine. Modified ICE can utilize hydrogen in place of gasoline. Optimized hydrogen...

The LH Storage

Evaporator

The liquid hydrogen LH2 storage system is a cryogenic, double wall type, and vacuum super-insulated tank. It consists of an inner vessel of cryogenic chromium-nickel steel to hold liquid hydrogen at a temperature of -253 C and pressure of 0.8 MPa, and a supporting outer vessel of carbon steel. The space between the inner and the outer vessels is under vacuum and super-insulated with perlite. Fig. 3.11 shows a simplified piping and instrumentation diagram P amp ID of the LH2 tank installed at...

Storage at Depot LH

Similar to the previous object 5.3.1 the expected frequency of the accident scenarios considered for the LH2 storage at the hydrogen filling station was synthesised from the component failure data associated with each of the identified failure modes, using the FTA approach. The accident scenarios considered for the study objects can be classified into two TOP events, i.e. instantaneous and continuous. Additionally, the continuous release scenario includes hydrogen release both in the liquid and...

Risk Acceptance Criteria

Curve Risk Aversion

All actions, decisions or situations involve some level of risk, though in most cases the risk is very low. Very low or reasonable risk is considered to be acceptable. Many regulatory frameworks require the management of risk to a level that is reasonable but fall short of defining the specific criteria for major unwanted events. In many risk assessments it may be necessary to determine the level of acceptable risk during the Scoping process. The criteria must...

Hydrogen Private

Evaporator

Size of little fuel cells technologies and internal combustion engines are today implemented. They showed excellent performance and safety in hydrogen city buses as well as in private cars. For example, BMW has successfully demonstrated hydrogen private cars e.g. BMW 753i for the past five or more years, since 1990 51 . Hydrogen fuel in the vehicle can be stored in gaseous form compressed gas , as a liquid -253 C , or in solid media. A cryogenic hydrogen LH2 storage for vehicles offers great...

The GH storage

The high-pressure hydrogen tank of the plant stores the largest hydrogen inventory of 5000 Nm3 compared to other components. It may be the largest contributor to societal risk as assessed in this study. Therefore, the study is focused on the two horizontal cylindrical high-pressure hydrogen storages Fig. 3.4 with an operating pressure of 3 MPa at ambient temperature. The tank is filled directly from the water electrolysis in the plant generated from the two low-pressure electrolyzers requiring...

Hydrogen Storage at Depot

The study considered the large-scale liquid hydrogen storage as depot , having a capacity of 270 m3 270,000 litres , and situated in Ingolstadt. It is used to store hydrogen in the liquid phase 16,000 kg of LH2 at temperature of -253 C and pressure of 1.3 bar Section 3.4 . The hydrogen plant is subjected to the accident regulation of German Storfallverordnung 78 . The hydrogen storage has a maximum liquid inventory of 16 tons, which is more than the quantity thresholds Section 5.1 . Therefore...

Dispersion Models

Vapor Cloud Explosion

The dispersion model implemented in the PHAST is called the Unified Dispersion Model UDM developed by 203 . The UDM calculates a dispersion in the downwind direction all phases between near-field and far-field dispersion including possible touchdown, rainout and subsequent pool formation and re-evaporation . Fig. 4.7 shows the movement of the cloud in the downwind direction for the steady-state continuous dispersion. The Cartesian coordinate x,y,z correspond to the downwind, cross wind and...

Risk Calculations

The model is an analytical model used to calculate the risks associated with hydrogen hazards developed following QRA procedure given by several authors. One of the procedures was given by 205 . They developed a model called MPACT population impact of toxic and flammable effects model implemented in the SAFETI DNV software. The MPACT is a mathematical model that calculates a number of results relating to the impact on the land and population potentially affected by the various toxic and or...

Hydrogen Safety Properties

Ignition Energy Gasoline

Hydrogen is the simplest element, has three isotopes hydrogen at wt 1.008 H , deuterium at wt 2.0141 D , and tritium at 3.0161 T . Hydrogen is very abundant, being one of the atoms composing water. Whereas hydrogen atoms exist under certain conditions, the normal of pure hydrogen is the hydrogen molecule, H2, which is the lightest of all gases 190 . The hydrogen molecule exists in two forms, ortho-hydrogen and para-hydrogen, depending on the nuclear spins of the atoms. A phase diagram of...

Intensity level kWm Times Probit value Lethality level

Blast Damage Tables

The purpose of the explosion impact models is to predict the impact of blast overpressure and projectiles on people and objects. Explosion effects have been studied for many years, primarily with respect to the layout and sitting of military munitions stockpiles. Explosion effects are classified according to effects on structures and people 2 . 4.5.4.2.1 Effect Blast on Equipment and Structures Explosion overpressure level and damage effect on structures are shown in Table 4-11. Overpressure...

Road Tanker Truck

Tank Truck Pressure Relief

It seems likely that liquid hydrogen will be delivered to filling stations by LH2 tanker trucks because LH2 does not have to be transported under pressure. The volume of fuel that can be transported is much larger than what is possible with the compressed gas. Nevertheless, the density of liquid hydrogen is lower than that of other fuels e.g. gasoline , and the tanker has to be well insulated. Therefore, only around 2,000 to 4,000 kg can be delivered by a single tanker, enough to fill 400 to...

Flammability

Flammable Hydrogen Methane Propane

Three things are needed for a fire or explosion to occur a fuel, oxygen mixed with the fuel in appropriate quantities and a source of ignition. Hydrogen, as a flammable fuel, mixes with oxygen whenever air is allowed to enter a hydrogen vessel, or when hydrogen leaks from any vessel into the air. Ignition sources take the form of sparks, flames, or high heat. All fuels burn only in a gaseous or vapour state. Fuels like hydrogen and methane are already gases at atmospheric conditions, whereas...

Accident Scenarios of the Study Objects

The FMEA method has been used to define an initial list of incidents that consider all possible breaks or ruptures of items of equipment which would lead to a loss of containment called accident scenarios . The considered systems mainly consist of a tank and piping system. Each of them, of course, may break or rupture in an infinite number of ways. For example, a pipe break may be any size from a pinhole to a full bore rupture and may be occurred any position between the pipe ends. This...

Hazard Identification Techniques

Fermenter Control Factor Pressure

Depending on the extent of the consequences of the potential major hazards, the sources of hazard may be determined by simple means such as checklists, or by more complex methods such as HAZOP, FMEA, F amp EI, and so on. The study uses the FMEA method to identify potential hazards related to the hydrogen system. The following section describes these methods. The word of HAZOP is an abbreviation for hazard and operability study. HAZOP 107 is a simple yet structured methodology for hazard...

Hydrogen Production

Methanol Production Energy Sources

Although hydrogen is the most abundant element in the Universe, it does not exist in free state in any significant amount on the Earth. It is found almost always chemically bound to other elements such as water, biomass, or fossil fuels. Molecular hydrogen, therefore, must thus be extracted from compounds such as water or organic molecules. Various methods of production have unique needs in terms of energy sources such as heat, light, electricity and generate specific by-products. Figure 2.4...

Risk Measures and Presentation

Risk Profile Examples

In general, risk is a measure of economic loss, human injury or environmental damage in terms of both the likelihood and the magnitude of the loss, injury or damage 2 . The study describes risk measures which estimate risk of human fatality caused by the immediate impact of hydrogen accidents fire and explosion. Two common ways used of combining incident frequency and consequence data to produce risk estimates, i.e. individual risk and societal risk. Individual risk IR measures are single...