Vapours

About: Vapours is a research topic. Over the lifetime, 1153 publications have been published within this topic receiving 15022 citations.

Combined Heat and Mass Transfer during Condensation of Vapours Mixture and Non-Condensable Gas in a Vertical Tube

Abstract: The problem of laminar film condensation from binary vapours mixture with the presence of non-condensable gas (air) flowing in a vertical tube is numerically investigated. The set of the non-linear parabolic equations expressing the mass conservation, momentum, energy, and species diffusion in both phases with the boundary conditions are resolved by using a finite difference numerical scheme. A comparative study between the results obtained for three cases (water-ethanol-air, water-methanol-air, and ethanol-methanol-air) under the same conditions is made. The impact of varying the wall temperature, the inlet vapour mass fractions, and the inlet liquid mass flow rate on the conjugate the heat and mass transfer during the condensation of the studied mixtures are examined. It is found that the condensation of water-methanol-air corresponds to a higher latent heat flux QL2 and accumulated condensation rate Mr2 when compared with water-ethanol-air and ethanolmethanol-air. Moreover, the nature of the fluid plays an important role in the heat and mass exchanges.

The effect of condensate pattern on heat transfer during the condensation of binary mixtures of vapours of immiscible liquids

Abstract: The condensation of mixtures of vapours of immiscible liquids is a process which occurs frequently in the oil and chemical process industries, particularly where such processes as steam distillation, heterogeneous azeotropic distillation and solvent drying are used. Yet the process is not understood. The discrepancies between the heat transfer coefficients reported by previous workers in this field are so large that none of the published correlations can be confidently used for design purposes. The relationships found between heat transfer coefficient and temperature driving force differ so widely that it is impossible to predict., without prior experimentation, the behaviour of condensers when operating conditions are changed. The present state of knowledge in this field is such that it is not known whether the factor controlling heat transfer rate during condensation is simply the conductive resistance of the condensate layer, or whether the conditions at the vapour–liquid interface are of importance. A need for further work in this field is obvious. The work described in this thesis covers the design and development of an apparatus to investigate the process of condensation of mixtures of vapours of immiscible liquids and an experimental study in which local heat transfer coefficients have been measured and related to visual observations of the condensate flow pattern.

Condensation of vapours from beer brewing processes

Abstract: In condensing vapours from processes to dry malt and/or brew beer, the condensation (4) is passed to a an ultrafiltration and microfiltration station, using a filter (5) of inorganic material with a pore dia of max 1 mu m and especially of 0001-02 mu m, for its separation into a water fraction (6) and a retained fraction (7) The water fraction (6) is used again as a permeate (61) or water supply, especially in the malting and brewing operations