Filtern
Erscheinungsjahr
- 2021 (5) (entfernen)
Dokumenttyp
- Zeitschriftenartikel (3)
- Vortrag (2)
Schlagworte
- Explosionsgrenzen (2)
- Explosionsschutz (2)
- Hydrogen (2)
- Zündenergie (2)
- Zündquellen (2)
- Auswirkung von Explosionen (1)
- Closed vessel combustion (1)
- Date center (1)
- Diluent additions (1)
- Economic analysis (1)
Organisationseinheit der BAM
- 2 Prozess- und Anlagensicherheit (5) (entfernen)
Eingeladener Vortrag
- nein (2)
Hinsichtlich ihrer sicherheitstechnischen Kenngrößen (STK) unterscheiden sich Wasserstoff und Erdgas zum Teil stark. Im Vortrag werden verschiedene STK von Erdgas/Wasserstoff-Gemischen im Abhängigkeit des Wasserstoffanteils vorgestellt und die Auswirkung der Beimischung von Wasserstoff zum Erdgas auf die Wirksamkeit von Explosionsschutzmaßnahmen erläutert.
In this lecture the safety related properties og hydrogen compared to other fuel gases and the explosion protection measures of avoiding flammable mixtures, avoiding ignition sources and mitigating the consequences of explosions when handling hydrogen and hydrogen mixtures are presented.
The Joint European Summer School JESS 2021 addresses these issues by offering high quality graduate level courses on selected topics of vehicle technology, innovation & business development, safe handling of hydrogen, and modelling. The course content is tailored to the needs of a diverse audience: newcomers to the field, experienced students, and young professionals working at the forefront of fuel cell and hydrogen applications.
The data center needs more and more electricity due to the explosive growth of IT servers and it could cause electricity power shortage and huge carbon emission. It is an attractive and promising solution to power the data center with hydrogen energy source. The present work aims to conduct an economic analysis on the hydrogen-powered data center. Configurations of hydrogen-powered and traditional data centers are compared and the differences focus on backup power system, converter/inverter, fuel cell subsystem, carbon emission, hydrogen and electricity consumptions. Economic analysis is conducted to evaluate the feasibility to power the data center with hydrogen energy source. Results show that electricity price increasing rate and hydrogen cost are the main factors to influence economic feasibility of hydrogen-powered data center. When the electricity price keeps constant in the coming two decades, the critical hydrogen price is about 2.8 U.S. dollar per kilogram. If the electricity price could increase 5% annually due to explosive growth of electric vehicles and economy, critical hydrogen price will become 6.4 U.S. dollar per kilogram. Hydrogen sources and transportation determine the hydrogen price together. Hydrogen production cost varies greatly with hydrogen sources and production technologies. Hydrogen transport cost is greatly influenced by distances and H2 consumptions to consumers. It could be summarized that the hydrogen-powered data center is economic if hydrogen could be produced from natural gas or H2-rich industrial waste streams in chemical plant and data center could not be built too far away from hydrogen sources. In addition, large-scale hydrogen-powered data center is more likely to be economic. Solar hydrogen powered data center has entered into a critical stage in the economic feasibility. Solar hydrogen production cost has restrained the H2 utilization in data center power systems now, since it could be competitive only when more strict carbon emission regulation is employed, hydrogen production cost reduces greatly and electricity price is increasing greatly in the future. However, it could be expected solar hydrogen-powered system will be adopted as the power source of data centers in the next few years.
The flammable hydrogen-blended methane–air and natural gas–air mixtures raise specific safety and environmental issues in the industry and transportation; therefore, their explosion characteristics such as the explosion limits, explosion pressures, and rates of pressure rise have significant importance from a safety point of view. At the same time, the laminar burning velocities are the most useful parameters for practical applications and in basic studies for the validation of reaction mechanisms and modeling turbulent combustion. In the present study, an experimental and numerical study of the effect of hydrogen addition on the laminar burning velocity (LBV) of methane–air and natural gas–air mixtures was conducted, using mixtures with equivalence ratios within 0.90 and 1.30 and various hydrogen fractions rH within 0.0 and 0.5. The experiments were performed in a 14 L spherical vessel with central ignition at ambient initial conditions. The LBVs were calculated from p(t) data, determined in accordance with EN 15967, by using only the early stage of flame propagation. The results show that hydrogen addition determines an increase in LBV for all examined binary flammable mixtures. The LBV variation versus the fraction of added hydrogen, rH, follows a linear trend only at moderate hydrogen fractions. The further increase in rH results in a stronger variation in LBV, as shown by both experimental and computed LBVs. Hydrogen addition significantly changes the thermal diffusivity of flammable CH4–air or NG–air mixtures, the rate of heat release, and the concentration of active radical species in the flame front and contribute, thus, to LBV variation.
A series of experiments were conducted in a 10L closed and vented tube with L/D = 10.0, and effects of initial fuel volume concentration, inert gas dilutions (diluted by N2 and CO2), inert gas–water mist twin fluid medium dilutions (diluted by N2-H2O twin fluid medium, CO2-H2O twin fluid medium) and end boundary conditions on overpressure transients of hydrocarbon fuel–air mixtures explosion were revealed. Results show that the overpressure-time profiles consistent with the dynamic evolution law of ‘approximately zero-1st overpressure rising stage-2nd overpressure rising stage-descending stage’, and ‘rate of overpressure rise-time’ curves exhibit the characteristics of multi-stages and multi-peaks, such as (dp/dt)(1,max), (dp/dt)(1,min), (dp/dt)(2,max) and (dp/dt)(2,min). Specifically, as the fuel volume concentration increased, both the maximum overpressures (pmax), and the maximum rates of overpressure rise ((dp/dt)(1,max) and (dp/dt)(2,max)) show a variation trend of increasing firstly and then decreasing, while the corresponding times (tmax, θ(1,max) , θ(2,max)) show a total different variation trend. Moreover, when YCH is lower than 1.88%, the value of (dp/dt)(1,max) is greater than (dp/dt)(2,max), while the value of (dp/dt)(1,max) was less than (dp/dt)(2,max), and when YCH was higher than 1.88%. The addition of N2 and CO2 can obviously inhibit the explosion intensity of hydrocarbon fuel, and the inhibition effect of CO2 is better than that of N2. Due to the synergy inhibition effect of the inert gas and ultrafine water mist, all the values of pmax, (dp/dt)(1,max) and (dp/dt)(2,max) diluted by inert gas-ultrafine water mist twin fluid medium were smaller than those diluted by sole inert gases. In addition, there are significant differences in the overpressure-time and the rate of overpressure rise-time profiles between closed and end venting explosions. The values of maximum overpressure and the rates of overpressure rise of the closed explosion were higher than those of the venting explosion, but the minimum rate of overpressure rise is a smaller one.