GB188703A - Improvements in or relating to methods of and apparatus for the heating or cooling of liquids or admixed solids and liquids in evaporative or like treatment thereof - Google Patents

Abstract

188,703. Rigby, T. June 16, 1921. Micltiple-effect apparatus; vapours, utilizing for effecting further evaporation.-Relates to multiple-effect apparatus in which vapour from the final effect or from one of the final effects is compressed and used as heating-medium in the first effect or one of the first effects. The energy required for the compression is derived from a natural direct source of mechanical energy, such as a fall of water, and heat losses are made up by steam from an electrically-heated boiler, the energy for which is derived from the same source. The ordinary steam supply and condensing arrangements are retained in order that the amount of evaporation effected by the steam and by the energy of compression may be varied. Liquid is added to the vapours before or after compression, so as to absorb the superheat and generate make-up vapours. As applied to the apparatus described in Specification 187,260, in which a number of multiple effect plants with overlapping temperature ranges are used, and in which the final effects of each plant are connected to a main 7 which leads by a valve 13 to a condenser 9, a branch pipe provided with a valve 15 leads to a compressor 17, the compressed vapours being led by pipes 25, 27 to the heating- spaces 21, 23 of the first effects of each plant. The condensates from each effect are cooled by flashing off vapour into effects at lower pressures and pass by a main 33 to the condenser 9. The liquid to be evaporated fed through a pipe 45 may be preheated in coils 65, 67 by the vapours before or after compression and by non-condensible gases withdrawn from the heating spaces of the first effects of each plant by valved pipes 41, 43. Non-condensible gases from the later effects are withdrawn by pipes 37, 39 leading to the main 7. The liquid to be separated is fed in parallel to the effects of each plant and the concentrated liquid is withdrawn in parallel through pipes 53, 55, vapours being flashed off to cool the liquids by connections 57, 59 to effects at lower pressures. Steam may be supplied to the heating- spaces of the first effects from an electrically heated boiler 69.