Safety assessments and environmental impact statements for facilities require an estimation of airborne releases. Aerosols generated by accidents are being investigated to develop the source terms ...for these releases. A severe accidental release event could be a pressurized powder release. Pressurized powder release experiments performed in static air measured the mass airborne and particle size distribution of these aerosols as a function of source size and containment pressure. Both containment pressure and source size were significant in pressurized powder releases. Release in static air can be estimated using the relationships developed in this work. Weight percent of the source powder airborne ranged from ∼2 to 24%. Mass median aerodynamic equivalent diameters of the airborne particles ranged from 5 to 19 µm. All of the pressurized releases produced a significant fraction of respirable particles 10 µm AED and less.
Burnett discusses a method for predicting the magnitudes of unbalanced forces caused by pressure surges in petroleum liquid pipelines. Burnett concludes that the formation of vapor pockets should be ...avoided as far as possible.
If the general public is to use hydrogen as a vehicle fuel, customers must be able to handle hydrogen with the same degree of confidence, and with comparable risk, as conventional liquid and gaseous ...fuels. Since hydrogen is stored and used as a high-pressure gas, a jet release in a confined or congested area can create an explosion hazard. Therefore, hazards associated with jet releases from leaks in a vehicle-refuelling environment must be considered. As there was insufficient knowledge of the explosion hazards, a study was initiated to gain a better understanding of the potential explosion hazard consequences associated with high-pressure leaks from hydrogen vehicle refuelling systems. Our first paper 1 describes the release and subsequent ignition of a high-pressure hydrogen jet in a simulated dispensing area of a hydrogen vehicle refuelling station. In the present paper, an array of dummy storage cylinders with confining walls (to represent isolation from the forecourt area) was used to represent high-pressure hydrogen cylinder storage congestion. Experiments with ignition of premixed 5.4 m × 6.0 m × 2.5 m hydrogen-air clouds and hydrogen jet releases up to 40 MPa pressures were performed. The results are presented and discussed in relation to the conditions giving the highest overpressures. We concluded from the study that the ignition of a jet release gives much higher local overpressure than in the case of ignition of a homogeneous mixture inside the cylinder storage congestion area. The modelling of these results will be presented in Part 2 of this paper.
•Array of dummy storage cylinders with confining walls was used for experiments.•Experiments with ignition of premixed 5.4 m × 6.0 m × 2.5 m hydrogen-air clouds.•Experiments with hydrogen jet releases up to 40 MPa pressures were performed.•It was concluded that the ignition of a jet release gives much higher local overpressure.
Pipeline hydraulic and surge analysis studies of the Saudi Aramco East-West crude-oil pipeline assisted in expanding the system's capacity by 50%. Surge studies predicted that operational upsets ...cause excessive surge pressures in the pipeline system at new flow rates. Additional surge studies showed that surge-relief stations must be located downstream from each of 6 pump stations. The new surge-relief stations and an increase in capacity of existing surge-relief stations protect the pipelines at the higher flow rates. The hydraulic and surge analysis studies and the system simulation are described in detail.
Coal and gas outbursts are complex dynamic phenomena and are highly hazardous. This article established an experimental system to research the damaging effect of gas on particulate coal during coal ...and gas outbursts, which replicated the outburst scenario by instantaneously releasing different-pressure gas. The results show that the higher the gas pressure is, the larger the new surface area is, and the gas damages the pulverized coal more drastically. The mass ratio of new granular size coal is between 8-27%. The surface area increased significantly (73.0%-245.2%). The mean order of increasing surface area is SC (1.102 m
2
)> DC (0.9875 m
2
)> SN (0.8999 m
2
)> DN (0.8369 m
2
), which indicates that the extent to which gas destroys particulate coal is inversely proportional to the solidity coefficient and positively proportional to the adsorptivity. The ability of weakly adsorbable gases to break particulate coal is more affected by gas pressure. The degree of breakage of low-firmness coals is more responsive to gas pressure. The percentage of coal mass broken by gas is positively correlated with gas pressure and adsorptivity and negatively correlated with the firmness coefficient. Finally, the quick release of gas occurs in three stages: an acceleration section (0-0.05 s), a high-speed section (0.05-0.15 s), and a deceleration section (after 0.15 s).
If the general public is to use hydrogen as a vehicle fuel, customers must be able to handle hydrogen with the same degree of confidence, and with comparable risk, as conventional liquid and gaseous ...fuels. The hazards associated with jet releases from leaks in a vehicle-refuelling environment must be considered if hydrogen is stored and used as a high-pressure gas since a jet release in a confined or congested area can create an explosion hazard. As there was insufficient knowledge of the explosion hazards, a study was initiated to gain a better understanding of the potential explosion hazard consequences associated with high-pressure leaks from hydrogen vehicle refuelling systems. This paper describes the experiments with a dummy vehicle and dispenser units to represent refuelling station congestion. Experiments with ignition of premixed 5.4 m × 6.0 m × 2.5 m hydrogen–air clouds and hydrogen jet releases up to 40 MPa (400 bar) pressure are described. The results are discussed in terms of the conditions leading to the greatest overpressures and overall conclusions are made from these.
► Explosion consequences of high-pressure leaks from H2 vehicle refuelling systems. ► Experiments with ignition of premixed 5.4 m × 6.0 m × 2.5 m H2–air clouds. ► Experiments for H2 jet releases up to 40 MPa (400 bar) pressure also carried out. ► Highest far field overpressures seen for premixed H2–air ignition in an open area. ► For jet releases, highest overpressures seen in trial with shortest ignition time.
