SU1274697A1 - Film evaporator - Google Patents

Abstract

The invention relates to film evaporators used in distillation desalination plants, prevents the film of evaporated liquid from overheating and ensures its evaporation in a drip free mode. The film evaporator comprises a housing, horizontal heating tubes arranged therein, installed inside cylindrical guide elements, a secondary steam separator, a feeding chamber and a brine chamber. Film evaporator is characterized in that the cylinders of the guide elements are equipped with devices for removing the vapor-liquid mixture from the flowing film of liquid. 3 il.

Description

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The invention relates to the field of evaporation technology and can be used in distillation desalination plants, as well as as evaporators of some industries, such as chemical, food, refrigeration, etc.

The purpose of the invention is to prevent the initial liquid from overheating and ensuring its evaporation in a pack-free mode.

FIG. 1 shows a film evaporator, a cross-section; in fig. 2 — node 1 of pa of FIG. I; on f | n 3 - the same, the embodiment.

The film expander contains a cylindrical body 1, horizontal greypdys pipes 2 spaced in it by vertical rows, reinforced in pipe fittings (not shown) and installed inside guide elements 3, mounted in interconnected cylinders and placed between the plates - upper 4 and perforated bottom 5.

On the outer surface of the guide elements are made (installed) of a device for removing a vapor-liquid s-mass. So, for a working fluid containing salts dissolved in it, for example, sea water, the discharge devices are more expedient to perform as a calibrated orifice 6 (Fig. 2). For liquids that do not contain dissolved salts, the latter are made in the form of a waste spring valve 7 ( Fig. 3). The valve 7 communicates with its working gauge 8 with the initial liquid through the usual opening 9 in the wall of the guide element. Restriction on the use of a waste valve due to that. that during the operation of the evaporator in seawater, the inner part of the claus will be clogged with deposits of its fields, which will lead to a deterioration of its performance. In the upper part of the apparatus of the evaporator housing there is a mixing chamber 10, and in the lower part of the apparatus there is a brine to the chamber 11. / The purifier of secondary steam from brine droplets is provided by the film separator equipped with a separator 12.

For supplying the source liquid, heat carrier, removal of brine, condensate and secondary steam in the evaporator, install 1 steam pipe.

Nlenochny evaporate. Works as follows.

The original sea water from the chamber 10 through the openings of the upper plate 4 enters under the sand in the heating

pipes 2 and flows through them in the form of a liquid film with a speed that is determined by the flow rate and the gap of the annular gap between the surface of the pipes 2 and their guide elements 3. A tenant is pumped inside the heating pipes. The resulting secondary vapor, together with the source liquid, in the form of a two-phase flow moves from top to bottom of a vertical row along the heating tubes. Before the two-phase flow enters the downstream heating tube, it is equal in weight to the amount of secondary steam formed on the upper tube, through the injector devices 6 is released into the annular space of the apparatus (space between the guide elements of the rows) and turns into secondary steam ( due to reduced pressure in the interfacial space). The separation of the secondary steam formed on the lower heating tubes from the brine is carried out in brine tank 1 1. A secondary charge enters the same chamber and from the annular space through the holes in the lower perforated plate 5. Next, the secondary charge is removed from the brine tube. from the evaporator, pass previously through the separator 12.

Depending on the heat load of the heating tubes, the type and flow rate of the source fluid, the value of the additional heating temperature of the fluid in the film evaporator, the two-phase flow can be effected not before supplying it to each heating tube, but after two, three, etc. pipes (determined by experiment or by calculation). In this case, in each vertical row through exhaust devices, it is necessary .V10 to release by weight such a two-phase flow as the secondary vapor forms on the located above heating pipes. Depending on the type of exhaust device (Fig. 2 or 3) and the two-phase flow required for discharge from the annular space, the required number of exhaust devices is determined.

Thus, the release of secondary steam in terms of its formation to the heating pipes in the form of a vapor-liquid mixture through the discharge devices of the guide elements prevents the initial liquid from overheating and deposition on the heating pipes, which significantly expands the scope of film desalination and increases its operational capabilities.

Claims (1)

Invention Formula Film evaporator, comprising a case, horizontal heating pipes housed in it by vertical pipes, fixed in tube sheets and installed inside guide elements made in the form of interconnected cylinders, secondary steam separator, feeding and brine chambers, characterized by that, in order to prevent the film of the initial liquid from overheating and to ensure its evaporation in a non-boiling regime, the guides of the guide elements equipped with devices for removal of the pars-liquid mixture from the flowing film of liquid. Mors / (7 ten d / 77Opi / {// 6 / i / LOR // fug I) FIG. 2 fig.Z