China 
Africa 
Explore chapters and articles related to this topic
Failure Modes
Published in David A. Hansen, Robert B. Puyear, Materials Selection for Hydrocarbon and Chemical Plants, 2017
David A. Hansen, Robert B. Puyear
All of the above forms of hydrogen cracking begin with wet hydrogen sulfide corrosion, which supplies hydrogen as a corrosion product when the sulfide ion combines with iron to form iron sulfide. The sulfide ion is a cathodic poison, encouraging two phenomena. Nascent hydrogen tends to dissolve into the metal rather than combining with another hydrogen atom to form hydrogen gas.Normally, this type of corrosion is rapidly slowed by the formation of a polarizing layer of H2 at the anode. However, the sulfide ion prevents such polarization. Thus, corrosion continues, with the generation of a large amount of nascent hydrogen, until the corrosion process is brought to a halt by the formation of a thick film of dense iron sulfide.
Characterisation of paraffin-based hybrid rocket fuels loaded with nano-additives
Published in Journal of Experimental Nanoscience, 2018
Md. Zishan Akhter, M. A. Hassan
A novel hybrid rocket fuel composition has been proposed which comprises of Paraffin wax and HTPB as base, blended with Lithium aluminium hydride (LiAlH4) and Magnesium hydride (MgH2) nanoparticles. A detailed investigation on rheological, thermal and ballistic characterisation of the paraffin-based hybrid rocket fuels had been carried out. It was observed that the Magnesium hydride doped hybrid fuels exhibit lower viscosity as compared to the Lithium aluminium hydride doped counterpart. It signifies comparatively greater entrainment-aided combustion phenomenon in the former case. LiAlH4 doped hybrid fuels exhibit solid-like behaviour in contrast to the MgH2 doped fuels. Thus, LiAlH4 doped fuels are predicted to be comparatively more stable in the solid phase than the MgH2 doped one. TGA/DTA data revealed that LiAlH4 doped fuel is thermally more stable and produces relatively greater residual-mass as compared to the MgH2 doped fuel. Static ballistic firing provided the regression behaviour of prepared fuels. It was obtained that regression rate is significantly enhanced by nanoparticle doping in comparison to the base fuel (PW-HTPB). This can be attributed to the dehydrogenation of metal hydrides and production of metal nanoparticles (Al; in case of LiAlH4) during combustion. Nascent hydrogen promotes pyrolysis of solid grain while metal nanoparticles undergo exothermic oxidation thereby enhancing heat transfer to the fuel surface. The enhancement in regression rate of all the prepared fuels was observed to be significantly higher (350%–475%) than the conventional HTPB hybrid fuel, as predicted in literature. A power law governing regression rate of the tested hybrid fuels was developed.
Recent developments in the application of microwave energy in process metallurgy at KUST
Published in Mineral Processing and Extractive Metallurgy Review, 2018
Ju Shaohua, Pritam Singh, Peng Jinhui, Aleksandar N. Nikoloski, Liu Chao, Guo Shenghui, R.P. Das, Zhang Libo
The HF dissolves the TiO2 layer on the surface but it can also remove Ti metal, resulting in the formation of nascent hydrogen gas, which can further react with the Ti substrate, causing hydrogen embrittlement, deformation and cracks. Hence, HNO3 is added so that reaction (7) occurs preferentially over reaction (6), thereby decreasing the hydrogen gas released.