GB1319553A - Multiple effect evaporators - Google Patents

Abstract

1319553 Multiple-effect evaporators AEROJET-GENERAL CORP 19 April 1971 [10 Feb 1970] 20456/71 Heading B1B Multiple-effect evaporation of a liquor, e.g. brine, is carried out in a cylindrical housing 10 divided by barriers into effects 13..20 each containing a bundle 21, 22, 23 .. of vertical heat transfer tubes, the barriers being arranged so that the vapour flows perpendicular to the axis of the housing and in opposite directions in adjacent effects. Owing to the trapezoidal cross-section of the tube bundles, the vapour flow area decreases in the direction of vapour flow. Brine is introduced through conduit 30 to the interior of the tubes of bundle 21 of the first effect 13 and flows in film-form down the inner surface of the tubes. Steam is supplied through conduit 26 into chamber 27 of the first effect 13, and passes over the upper edge of wall 28 to condense on the outside surface of the tubes of bundle 21. A mixture of residual steam and non-condensible gas passes through apertures in wall 31, and is discharged through conduit 32. Steamcondensate is discharged through conduit 34. Some of the water evaporates from brine flowing down the tubes of bundle 21; and the vapour leaving the lower ends of the tubes flows, in a direction normal to the axis of the housing, into chamber 36 and the space surrunding the tubes of the next effect 14. Concentrated leaving the first effect through conduit 137 may be pumped to the tubes of the second effect via a chamber 29 where partial flash evaporation takes place due to pressure-decrease. The operation of the subsequent effects is similar to that already described, but the direction of vapour flow in each effect is opposite to that in the adjacent effect.