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Papers by Steven Betteridge

13th International symposium on hazards, prevention, and mitigation of industrial explosions (ISHPMIE), Jul 27, 2020

International audienceThe SPARCLING JIP was launched by TOTAL, AIR LIQUIDE, SHELL, GRTgaz & I... more International audienceThe SPARCLING JIP was launched by TOTAL, AIR LIQUIDE, SHELL, GRTgaz & INERIS. The goal of the project was to produce high-quality experimental data on the size distribution and velocities of the LNG droplets using a dual PDA (Phase Doppler Anemometer), following the pressurized release of LNG. One area of particular concern is the potential for rainout and subsequent pool dispersion. The test programme was managed and run by INERIS at their test site at Verneuil-en-Halatte on behalf of the members of the JIP. The paper describes in detail the testing bench and test protocol, as well as the lessons learned from the use of the bench. The occurrence of rainout is then discussed

In recent years there has been a drive to use cleaner and more efficient fuels. Liquefied Natural... more In recent years there has been a drive to use cleaner and more efficient fuels. Liquefied Natural Gas (LNG) is one of the fuels now being considered, especially for commercial vehicles such as trucks and ferries. LNG has a long and excellent safety record it has been safely delivered across the oceans for over 50 years. In using LNG as a transport fuel, it is important to ensure continued safe operations in this new value chain. Next to liquefaction plants and regasification terminals this distribution chain also has retail fuel stations and bunker terminals relatively close to urban environments. Hence there are several questions that must be addressed: What are credible scenarios in this small scale distribution chain? Are the consequence models used today to safely manage risks appropriately validated? Do they predict the consequences correctly or are they too conservative and thereby adding unnecessary costs, to the investment, which do not result in improved safety?

In 2009, a series of experiments were conducted by Sandia National Laboratories at a large-scale ... more In 2009, a series of experiments were conducted by Sandia National Laboratories at a large-scale test complex in Albuquerque, New Mexico, in which Liquefied Natural Gas (LNG) was released onto the surface of a large pool of water and then ignited. These experiments involved the largest releases of LNG ever performed, with the spills covering a circular area up to 83 m in diameter. In the test with the largest LNG release rate, unexpected behaviour was observed. The flames did not cover the entire area of the LNG spill, but were instead limited to a smaller region, around 50 m in diameter. The height of the flames was also greater than expected from previous large-scale tests. One possible explanation for this behaviour is that in this very large scale test, the speed at which air and fuel vapour was drawn into the fire exceeded the local burning velocity. The flames could therefore not propagate upwind, against the entrained flow, and ignite the whole surface of the LNG pool. The ad...

In one of the very large LNG pool fire experiments conducted as part of the Phoenix tests for the... more In one of the very large LNG pool fire experiments conducted as part of the Phoenix tests for the US Department of Energy, the flames from the centrally-ignited pool fire did not cover the entire area of the LNG spill. This behaviour may be explained by the thermal updraft generated by the fire driving an inward flow of air and natural gas across the non-burning region that exceeded the burning velocity of the outwardly spreading flame front, thereby preventing the fire from spreading radially outwards to the extremities of the LNG spill.

Journal of Loss Prevention in the Process Industries, 2018

There has been a rising demand for natural gas across the World. In many countries, this demand i... more There has been a rising demand for natural gas across the World. In many countries, this demand is being satisfied through an increasing number of marine LNG Carrier (LNGC) deliveries and hence there is a safety requirement to understand the consequences of significant accidents that could lead to the catastrophic failure resulting in a large spill of LNG in a harbor. The impact of thermal radiation on LNGCs, terminal facilities and the public outside the site fence-line from an LNG pool fire on water could extend a long distance according to current empirical models. The Phoenix pool fire experiments were conducted by Sandia laboratories to validate these models for large LNG spills on water. It was observed that the pool fire did not extend across the entire area of an 80 m diameter LNG pool. In addition, the flame height was greater than expected and there was very little smoke obscuration compared to the 35 m tests at Montoir. This combination of physical phenomena made it difficult to use existing models to predict the consequences of thermal radiation, especially when extrapolating to different and potentially larger spill sizes. A recent study using empirical analysis and CFD demonstrated that the thermal updraft of a large fire will drive an inward flow of air and natural gas from the non-burning region with a velocity greater than the burning velocity of the outwardly spreading pool fire. Medium scale tests using a 4 x 1 m LNG pool in a fire tunnel confirmed that an artificially generated air-flow of 2.8 m/s was sufficient to stop the flame spread across the pool and confirmed the previous analysis. This paper describes an empirical model that has been developed based upon this analysis to account for the reduced pool fire size and successfully model the larger flame height that was observed during the Phoenix test. An analysis of large spills using this model showed that the calculated flame view factor was significantly reduced compared to pool fire models that predict that the fire will extend across the whole spill surface. The paper will also discuss the effect of water on combustion and hence provide an explanation for the reduced smoke obscuration that was seen during the Phoenix tests.

During the last ten years there has been a rising demand for natural gas across the World. In man... more During the last ten years there has been a rising demand for natural gas across the World. In many countries this demand is being satisfied through an increasing number of LNG tanker deliveries and the development of new LNG import terminals. In parallel, there is a safety requirement to understand the consequences of significant accidents that would lead to the catastrophic failure of the LNG storage and hence result in a large spill of LNG in a harbour. The impact of thermal radiation on tankers, terminal facilities and the public outside the site fence-line from an LNG pool fire on water could extend a long distance according to current empirical models. In the last couple of years the World's largest LNG pool fire experiment was conducted for the US Department of Energy to quantify these hazards for pool fires up to 100 m in diameter. Some of the results of the experiment were unexpected compared to previous large scale tests (diameters 20-35 m). Specifically (1) the flames did not cover the entire area of the LNG spill, (2) the flame height was much greater than expected based on previous large scale tests and (3) soot production rates were much lower than expected. This paper shows the latest work to understand the physical origin of these phenomena using both empirical modelling and a simple Computational Fluid Dynamics model developed using ANSYS CFX. Both approaches show that the thermal updraft generated by the fire drives a radially inward flow of air and methane from the non-burning region outside the pool fire. The velocity of this flow is predicted to be approximately 3.5 ms-1 and hence potentially greater than the burning velocity of the outwardly spreading pool fire. The additional air / fuel mixture being entrained into the fire may also account for the higher flame heights and reduced smoke generation.

Methane and Alkane Conversion Chemistry, 1995

The synthesis, characterisation and reactivity of an iron/sodalite catalyst for the partial oxida... more The synthesis, characterisation and reactivity of an iron/sodalite catalyst for the partial oxidation of methane to methanol are described and discussed. In a limited temperature range, ca. 410°C, and at 34 bar total pressure, the selectivity to methanol is found to be similar to that observed for the empty silica glass reactor. Before reaction, powder X-ray diffraction and 57Fe Mossbauer spectroscopy confirm the presence of Fe(III) in the sodalite framework. After reaction the structure is more complex, as revealed by 57Fe Mossbauer spectroscopy and transmission electron microscopy, and both Fe(II) and Fe(III) are present. In particular, small particles of Fe2O3, < 1μm in size are also present in the used catalyst. The nature of the active site is discussed in terms of an Fe(II)/Fe(III) couple involving both framework and nonframework iron.

Journal of Magnetism and Magnetic Materials, 1995

Polarised M6ssbauer spectroscopy was used to measure the in-plane and out-of-plane angles of the ... more Polarised M6ssbauer spectroscopy was used to measure the in-plane and out-of-plane angles of the magnetic moments in tape and powder samples of Co : ,-Fe20 3 in an applied field of 250 mT. The results indicate better alignment in the case of the tape sample, and demonstrates the usefulness of this technique.

IEEE Transactions on Magnetics, 1994

A new methodology for making quantitative micromagnetic measurements of the in-plane moment canti... more A new methodology for making quantitative micromagnetic measurements of the in-plane moment canting in Fe-based amorphous alloys, via polarized Mossbauer spectroscopy, is introduced and explained. The technique is applied to the measurement of the approach to magnetic saturation of a field-annealed FemB1~Si9 ribbon. It is demonstrated that even in a field of 200 kAm-' the moments are not completely saturated, and are canted by on average-3" to the applied field.