GB953686A - Process and apparatus for the separation of water and impurities from steam - Google Patents

Abstract

953,686. Centrifugal separators ; contacting gases with liquids. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. Oct. 8, 1962 [Oct. 10, 1961], No. 38074/62. Headings B1R and B2P. Steam containing water and solid impurities, such as water-insoluble salts and metal oxides, is separated into dry steam, pure water and water containing impurities by supplying the steam, through a tangential inlet 2, to the interior of a centrifugal separator 1 where, after initial separation, the steam is passed through a liquid screen of purified water in which the remaining impurities and some of the remaining water are caught, the steam being then led through a cyclone 4 provided in the separator above the screen and from which dry purified steam is discharged overhead and water is discharged via a pipe 22 in the bottom of the separator 1 into a water zone 7 where separated water and water from the liquid screen are passed through a central passage inside an annular space 5 provided above the zone 7 and beneath the inlet 2 and in which separated impure water with the highest concentration of impurities is collected. The liquid screen is provided by the purified water being fed through a line 10 either into an annular channel 3 and overflowing therefrom or to a closed perforated circular pipe. The remaining water particles containing the remaining solid impurities are agglomerated to form larger drops in the liquid screen and, as they travel down the separator, are whirled round by the incoming steam and flung outwards against the wall of the separator where, together with the initially centrifugally separated water and impurities, they are collected in the annular channel 5. The impure water is removed from the channel 5 by a line 11 while water substantially free of impurities flows over the upper edge of the channel into the zone 7. The cyclone has a tangential inlet 14 and a steam discharge pipe 15, which may be surrounded by a water collecting baffle 16 and which opens into an additional water-separation chamber to which is connected the purified steam discharge line 9 and a water discharge pipe 24. Supported on the flat bottom of the cyclone is a catch pot 18. Baffles 20 are provided externally of the catch pot to counteract rotation of the gases while allowing separated water to flow freely down the cyclone wall. Particles of water entrained by the gases towards the centre of the cyclone pass into the catch pot where they are removed by a pipe 23 tangential to its flat bottom. The pipe 22, which is also tangential to the bottom of the cyclone, together with the pipes 23, 24 discharge either directly into the space 7 or, preferably, as shown, into a box 6 serving as a liquid seal. The pure water may be returned to a steam boiler to which the separator is connected.