Hydrogen systems explosion

Hydrogen sulfide gas Hydrogen sulfide is a gas with a rotten egg odor. This gas is produced under anaerobic conditions. Hydrogen sulfide is particularly dangerous because it dulls your sense of smell so that you don t notice it after you have been around it for a while and because the odor is not noticeable in high concentrations. The gas is very poisonous to your respiratory system, explosive, flammable, and colorless. 

The risk to the public during consumer end use of hydrogen derives from the possibility of accidental fire and explosion, a direct consequence of the physical and chemical properties of hydrogen. These properties help to define the kinds of safety issues that must be addressed, the fundamental design goals for hydrogen systems, and the operational limitations of these systems. Table 9-1 summarizes the properties of hydrogen in contrast with those of other commonly used fuels. 

Corneil and Pimentel have studied, near room temperature, the hydrogen-chlorine explosion laser finding an isotope effect in the CI2-HD system for the reactions... 

Christmann K, Chehab F, Penka V, Ertl G (1985) Surface reconstruction and surface explosion phenomena in the nickel (110) hydrogen system. Surf Sci 152 356... 

An on/off switch can be useful. It can be as simple as a weatherproofed toggle switch rated above the amperage of the panel or array. Such a switch in a solar hydrogen system should be placed close to the panel and not near the electrolyzer unless it is explosive rated switch. A simple connector box which contains the contacts and/or diodes can also house the switch. 

Caution. Hydrogen forms explosive mixtures with air. The combustion system used for reduction should be thoroughly flushed with nitrogen before admitting hydrogen, and provision for venting the exit gas must be made. 

In order to be 100% safe from a hydrogen explosion (sources passivation air, CO2), a hydrogen removal system is installed before the CO2 passivation air enters the stripper. 

The reaction with fluorine occurs spontaneously and explosively, even in the dark at low temperatures. This hydrogen—fluorine reaction is of interest in rocket propellant systems (99—102) (see Explosives and propellants, propellants). The reactions with chlorine and bromine are radical-chain reactions initiated by heat or radiation (103—105). The hydrogen-iodine reaction can be carried out thermally or catalyticaHy (106). 

Criticality Precautions. The presence of a critical mass of Pu ia a container can result ia a fission chain reaction. Lethal amounts of gamma and neutron radiation are emitted, and a large amount of heat is produced. The assembly can simmer near critical or can make repeated critical excursions. The generation of heat results eventually ia an explosion which destroys the assembly. The quantity of Pu required for a critical mass depends on several factors the form and concentration of the Pu, the geometry of the system, the presence of moderators (water, hydrogen-rich compounds such as polyethylene, cadmium, etc), the proximity of neutron reflectors, the presence of nuclear poisons, and the potential iateraction with neighboring fissile systems (188). As Httle as 509 g of Pu(N02)4 solution at a concentration Pu of 33 g/L ia a spherical container, reflected by an infinite amount of water, is a critical mass (189,190). Evaluation of criticaUty controls is available (32,190). 

Hydroxylamine sulfate is produced by direct hydrogen reduction of nitric oxide over platinum catalyst in the presence of sulfuric acid. Only 0.9 kg ammonium sulfate is produced per kilogram of caprolactam, but at the expense of hydrogen consumption (11). A concentrated nitric oxide stream is obtained by catalytic oxidation of ammonia with oxygen. Steam is used as a diluent in order to avoid operating within the explosive limits for the system. The oxidation is followed by condensation of the steam. The net reaction is... 

Deduction. If a knowledge-based system has a set of facts, and new facts are provided to it, then rules of inference can be appHed to the set of facts to derive conclusions. For example, from the facts that (/) hydrogen and oxygen can react explosively at high temperatures, (2) air contains oxygen,... 

J) the atmosphere inside a particular reactor contains hydrogen, and (4) the reactor is at a high temperature, the additional fact that air has leaked into the feed to the reactor leads to the conclusion that an explosion can take place. The conclusion is based on applying deductive logic to the known facts. This is representative of the logic-based approach to knowledge-based systems. 

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