Showing papers on "Vapours published in 1986"

Composition and conductivity of a copper-air plasma

Abstract: The composition as well as the electric and thermal conductivities of a copper-air plasma at atmospheric pressure are determined for temperatures ranging from 5000K to 14000K and different values of copper content. The calculating procedure is indicated and through an analysis of the results it is shown that the characteristics of the medium can be modified quite significantly in the presence of metal vapours.

Process for eliminating solvents for cleaning the air contained in solvent vapours

Abstract: In a solvent elimination process, especially a solvent absorption process for purifying production waste air, pyrolysis gas, disposal site fermentation gas, bio gas or the like by removal of solvent vapours, the contaminated air is contacted in an absorption stage with a washing fluid, the contaminated washing fluid is subjected in a processing stage to thermal separation for recovering the pure washing fluid and, in a third stage, the liquid water/solvent mixture arising in the processing stage is subjected to water treatment, in which the solvent is separated off and the water is purified to such an extent that it can be re-used or discharged as effluent into a disposal system. In order to make the absorption in the first original stage more advantageous technologically and to allow an easier and more complete recovery of the washing fluid in the second stage, provision is made in the absorption stage that the absorption of the solvent vapours is carried out on dimethylpolysiloxane or a polyalkylene- modified siloxane oil of low oligomer content as the washing fluid. When a siloxane oil/water mixture is used, the processing of the contaminated washing fluid can be carried out in the processing stage in such a way that a water vapour rectification is possible without extraneous steam feed, with improved mass transfer. The absorption in the first stage can also be followed by an adsorption on a solid adsorbent for the recovery of low-boiling solvents (final purification) with a low water content.

Metal-organic chemical vapour deposition

Abstract: An MOCVD deposition technique wherein the pressure of reagent vapours within the reaction vessel (1) is maintained at a reduced pressure in the range 10⁻² to ∿10 millibars and contained mounted substrates (15) are heated non-inductively eg by an electric resistance circumferential furnace (5). In the above pressure range, high diffusivity of the reagent vapours ensures exposure of the substrates (15) to a uniform reagent mixture. A large number of substrates (15) may be processed simultaneously. As heating is non-inductive, an inert mounting (17) can be utilised avoiding the introduction of contaminants (eg carbon) into the deposited film.

Investigation of UV laser ionization in naphthalene and phenol vapours added to proportional chamber gases

Abstract: The ionization induced in organic vapours added to argon-methane proportional chamber gas by an UV laser emitting at a wavelength of 266 nm has been studied. At concentrations of 30–70 ppm and laser energy densities of 1 μJ/mm 2 , ionization densities of 10 3 electrons per mm 3 are obtained. These vapours are adsorbed by the chamber walls and difficult to remove. Procedures for gas cleaning are given.

Gas-Solid Reactions : Part VI. Interaction of Solid Chalcones With Bromine and Iodine Vapours

Abstract: Solid Chalcones (azylidene acetophenones) give, on exposure to bromine vapour at room temperature, the “trans-adduct” in quantitative or near-qu-antitative yield. Polymorphic forms of several compounds do not differ in thier bromination products. Iodine vapours do not cause cis-trans isomerisation in the solid cis-chalcones.

Process and apparatus for concentrating juices or the like by evaporation

Abstract: In a process for concentrating juices or the like by evaporation with aroma recovery, the juice is passed through a plurality of evaporators (12, 14, 16, 18), the evaporators (12, 14, 16, 18) being heated by the vapours of the juice formed in the evaporators and the vapours formed in at least one of the evaporators and, possibly, vapour condensate being fed to a rectification column (52) for aroma recovery. To reduce the consumption of heating steam at a high final concentration of juice, it is proposed that the evaporator (18) through which the juice flows last and the evaporator (16) connected to the rectification column (52) or an evaporator upstream of this in the juice flow are heated in parallel by mechanically compressed vapours (vapour compressor 36).

Method and apparatus for concentrating trace vapours in a gaseous medium

Abstract: The specification discloses a method and apparatus for concentration of vapours present in trace quantities in the atmosphere in a continuous and rapid manner. It relates especially to a device to enhance the concentration of trace vapours to such a level that they may be more readily analyzed by appropriate instrumentation. This is of considerable value in connection with the detection of certain vapours which are associated with explosive devices and bombs. These are of considerable importance now in connection with security at airports and the like. The specification discloses a method and apparatus for the continuous concentration of trace gases in a gaseous medium, such as air, comprising the steps of bringing the air into intimate contact with a suitable free-flowing adsorption powder in an adsorption region (13), passing the air containing the treated powder and adsorbed vapours through a cyclone separator (12) to produce a substantially power-free air stream and a powder containing adsorbed vapours, then passing the powder through a desorption region (40) whereby the powder carrying trace vapours is heated in a heating zone (45, 46) in the presence of a carrier stream at a temperature sufficient to release the adsorbed trace vapours of interest, and thus to produce a vapour- enriched carrier gas stream. The powder is then normally recycled into the air inlet stream (10).

Process and apparatus for recuperating hydrocarbon vapours.

Abstract: A process and an apparatus for collecting hydrocarbon vapours originating from tanks or reservoirs for liquid hydrocarbons. Under practically isothermal conditions, the hydrocarbon vapours are sucked up and condensed with the aid of a liquid ring vacuum pump (PaL) operating with a service liquid of substantially the same composition as the hydrocarbon to be collected; the liquid obtained is separated, in a decanter/separator (DS), from the gases which cannot be condensed under the operating conditions and a portion of the liquid obtained is recycled as service liquid for the liquid ring pump. A regulation device (7) makes it possible to sample the liquid hydrocarbon collected with a view to its storage. The recycled liquid is cooled at (E3) to a temperature which is sufficiently low to obtain, in the liquid ring pump, the vapour pressure desired for the condensation of the hydrocarbon vapours.

Nucleation in supersaturated vapours of solid and liquid naphthalene and phthalic anhydride

Abstract: The critical supersaturations of vapours of solid naphthalene and phthalic anhydride have been measured by using downward thermal diffusion cloud chamber. The experimental data have been fitted by an empirical fitting formula to allow predictions of behaviour of vapour-noncondesable gas mixtures of both compounds in condensation processes. Including the previously published data on critical supersaturations of vapours, measured above the triple point, the poT diagrams have been drawn for both compounds.