GB1239112A - - Google Patents

Abstract

1,239,112. Evaporators; polymerization; gas-liquid absorption. WIEGAND APPARATEBAU G.m.b.H. 14 Aug., 1969 [15 Aug., 1968], No. 40746/69. Headings B1B and B1X. In order to evaporate a liquid, or carry out a liquid-gas absorption process or a chemical reaction such as the polymerization of a solution or emulsion, the liquid is fed to a tubular duct, which is helically or spirally coiled about one or more axes, while a stream of gas and/or vapour is passed through the duct so that the liquid flows down the internal wall of the duct in the form of a annular film and issues from the entire periphery at the end of the duct. The diameter of the helix should be 0.25 to 8 times the diameter of the duct, and the spacing of consecutive turns of the helix should be between 1.75 and 150 times the diameter of the helix. The duct may be surrounded by a heating-or a cooling-chamber whereby the temperature of the liquid may be controlled. The liquid is supplied at a rate dependent on the hydraulic diameter of the duct. The gas (vapour) is supplied at a rate dependent on the viscosity of the liquid. The Fig. shows an evaporator comprising a helical tube 1 inside a heating chamber 4. Liquid to be concentrated, e.g. an aqueous solution of glucose, is preheated and fed into tube 1 through valve 8 and pipe 7. At the same time, saturated steam flows into tube 1 from chamber 5 which is supplied with steam through valve 11 and pipe 10. As the solution flows down the internal wall of tube 1, evaporation of some of the water takes place. The concentrated solution and vapour enter separator 15; and the concentrated solution is withdrawn from chamber 19 by pump 21. The vapour flows through pipe 22 to condenser 23, which is evacuated by pump 26. Tube 1 may be made of stainless steel and lined with polytetrafluoroethylene. Instead of using a helical tube, the process may be carried out in a helical channel in a block of heat-conductive material. The sulphonation of olefins with SO 3 is referred to; also the nitration or halogenation of aromatic compounds and the halogenation of alkanes.