Vessels liquid hydrogen

The U.S. military specification, M1L-P-27201B, requires 95% para content, 99.995% minimum hydrogen by difference, 50 vppm maximum total imputities, 9 vppm maximum combined nitrogen, water, and volatile hydrocarbons, 1 vppm maximum combined oxygen and argon, 39 vppm maximum helium, 1 vppm maximum carbon monoxide and dioxide, and a 10/40 micrometers nominal /absolute particulate filtration level. Liquid hydrogen is stored in double-walled vessels with evacuated pedite or multilayer insulation and transported in similarly insulated 50,000-L trailers or 900,000-L barges. 

In the industrial process, the chlorocarbon and liquid hydrogen fluoride feeds are pumped simultaneously into a complex liquid mixture of Sb(lII) and Sb(V) chlorofluondcs at temperatures in the 60-150 °C range The products are generally more volatile than the reactants and therefore distill preferentially from the reactor vessel, thus the reactor can be operated continuously. 

Liquid hydrogen fluoride has a large coefficient of thermal expansion, and temperature increases can result in contaiiuncnt failure if tliere is no room for tlicnnal expansion of the liquid. Thus liquid-full equipment presents a special liaztird. A liquid-full vessel is a vessel tliat is not vented and lias little or... 

A solution of 12.5 g (0.088 mole) of l,4-dioxaspiro[4.5]decane (Chapter 7, Section IX) in 200 ml of anhydrous ether is added to the stirred mixture at a rate so as to maintain a gentle reflux. (Cooling in an ice bath is advisable.) The reaction mixture is then refluxed for 3 hours on a steam bath. Excess hydride is carefully destroyed by the dropwise addition of water (1-2 ml) to the ice-cooled vessel until hydrogen is no longer evolved. Sulfuric acid (100 ml of 10% solution) is now added followed by 40 ml of water, resulting in the formation of two clear layers. The ether layer is separated and the aqueous layer extracted with three 20-ml portions of ether. The combined ethereal extracts are washed with saturated sodium bicarbonate solution followed by saturated sodium chloride solution. The ethereal solution is dried over anhydrous potassium carbonate (20-24 hours), filtered, and concentrated by distillation at atmospheric pressure. The residue is distilled under reduced pressure affording 2-cyclohexyloxy-ethanol as a colorless liquid, bp 96-98°/ 3 mm, 1.4600-1.4610, in about 85% yield. 

For road transport, liquid hydrogen (LH2) is transported in cylindrical super insulated cryogenic vessels in a semitrailer (see Fig. 12.5). The gross weight of a truck capable of carrying the LH2 container is typically about 401. The investment for a LH2 semitrailer amounts to about 500 000. The investment for a tractor capable to haul a semitrailer is about 160000. Table 12.3 displays the technical characteristics of hydrogen trailers. 

Into a platinum vessel containing 7.1 g. of 7-(9,10-dihydro-2-phenan-thryl)-butyric acid is poured approximately 100 g. of liquid hydrogen fluoride. The acid dissolves readily on swirling, and the colored solution... 

Brittle Failure (8). Brittleness is a principal consideration in selecting construction materials for liquid hydrogen service. Brittle fracture can result in the essentially instantaneous release of a vessel s contents, the hazard being a combined one of PV energy release and the possibility of fire and/or explosion. Three conditions must exist for a brittle fracture to occur 1) a stress riser, a crack, notch, or other discontinuity, 2) a section where the actual stress exceeds the yield stress of the material, and 3) a temperature below which failure occurs without appreciable plastic deformation. Metals that are satisfactory for liquid hydrogen service include aluminum, stainless steels, brass, and copper. Carbon steel is not suitable. 

The liquid hydrogen trailers are equipped with a three way full condition pressure limiting system (Figure 17) which coordinates inner vessel pressure, in one of three modes, with the safety... 

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