CH625869A5 - - Google Patents

Description

The present invention relates to a vertical vapor separator-superheater, comprising inside a common ferrule a lower part forming a separation zone and an upper part forming an overheating zone, the superheating zone comprising an axial zone for the arrival of dry steam, tubular bundles of superheating arranged in envelopes distributed around the central zone, and a peripheral zone for collecting superheated steam.

Already known from French patent No 72.21656 published under No 2187394, separators-superheaters of this kind, which are used in particular to dry and superheat steam from a high pressure expansion turbine, before its admission into a turbine expansion under lower pressure, by heat exchange with steam under higher pressure. Given the large expansions and contractions that occur in the tubular bundles of superheat steam, we are led to adopt special devices intended to allow these expansions and contractions without the appearance of excessive stresses, for example expansion lyres. These devices are relatively bulky and complicate any intervention on the tubular overheating bundles.

The object of the present invention is to remedy these drawbacks and to provide a vertical vapor separator-superheater which absorbs expansion and contraction of the tubular bundles without comprising any special device such as expansion lyres, and which allows easy extraction of the bundles tubular for their repair.

The separator-superheater according to the invention is characterized in that the envelopes of the tubular superheating bundles are fixed to the internal wall of a flexible ferrule itself fixed to the upper part of the common ferrule.

It also preferably includes at least one of the following characteristics:

- It comprises at its upper end a toroidal manifold for supplying superheating steam, connected by tubes to the upper ends of the tubular superheating bundles;

- Its lower part comprises an annular chamber for the admission of wet steam, connected, on the one hand, to openings for the introduction of wet steam, arranged so as to impart a swirling movement to this steam, and, on the other hand, from below, at the bottom of an axial zone provided with separating elements, by the intermediary of passages imparting to the steam a change of direction of approximately 180 °;

- The axial zone provided with separating elements is eccentric with respect to the common ferrule towards the side opposite to the openings for the introduction of wet steam, so as to ensure a substantially constant steam speed in the annular intake chamber.

There is described below, by way of example and with reference to the figures of the appended drawing, a vertical vapor separator-superheater according to the invention.

Fig. 1 shows the separator-superheater in vertical section, with partial cutaway of part of the envelopes of the tubular bundles of overheating.

Fig. 2 is an enlarged view of detail II of FIG. 1, representing the bottom of the thin internal shell and a superheater harness.

Fig. 3 is an enlarged view of a detail III of FIG. 1, representing a separating element.

Fig. 4 shows a diametrical section along the axis IV-IV of FIG. 1.

Fig. 5 shows a section along the axis V-V of FIG. 1.

Fig. 6 shows a diametrical section along the axis VI-VI of FIG. 1.

In fig. 1, the separator-superheater has an external pressure-resistant shell 1, supported by a usual annular support by a floor 2. It consists of a lower part 3 (forming a separator) and an upper part 4 (forming superheater). The lower part is fitted with 4A pipes for supplying wet steam. These open into an annular chamber 5 comprising in its lower part a passage 6 for communication with the bottom of the central part 9 containing the separators proper. In order to ensure a constant steam speed and, consequently, a constant steam flow rate around the entire periphery of the central zone 9, the latter, delimited by a prismatic sheet metal 60, is eccentric with respect to the axis of the separator- superheater, its axis being further from the supply pipes 4A (see fig. 6). The swirling flow in the chamber 5 ensures a first separation of the water droplets entrained by the vapor. The arrangement of the separating elements in the central zone 9 is also such that the vapor enters it only after having undergone a change of direction of 180 ° in the inlet preseparator delimited by the flange 61. This completes the preliminary separation of the water droplets contained in the vapor. The separated water collects in the bottom 7 of the shell and is evacuated through the tubing 8.

The partially dried vapor then rises vertically in the intervals such as 9A between stacks 10, 11 of separating elements formed by bundles of parallel corrugated sheets.

In order to ensure a substantially equal distribution of the vapor between the different separating elements, the interval between two stacks of separating elements decreases from the bottom to the top.

The structure of a separating element is shown on a larger scale in FIG. 3. Each element includes an inlet grille 40, ensuring an equal distribution of the steam flow rate,

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625869

parallel corrugated sheets 41, arranged between parallel lower and upper partitions 42 and 43, and an outlet grid 44.

The dried saturated vapor exiting from the separators meets in intervals between stacks of separators such as 12, arranged in such a way that the speed of the vapor is the same after it leaves the separators as before it enters them. Then the dried steam reaches the intermediate zone 13 of the separator-superheater. A fraction, for example 10% of the total flow, can be withdrawn directly before overheating by an outlet pipe 14. io

The rest of the dried saturated vapor rises in the upper part 4, through its axial zone 15, around which are arranged four superheater modules such as 16,17. These superheater modules are fixed by means of angles 33 (see FIG. 2) on the internal surface of a thin shell 30, itself welded by its upper edge to the upper bottom 31 of the separator-superheater. The lower edge of the ferrule 30 is connected by expansion bellows 37 to a horizontal flange 32, itself welded to the internal wall of the external ferrule 1.

The superheater modules are supplied with steam at high pressure 20 through the pipe 20, the O-manifold 21 and the short fittings 22 opening into the end chambers 23. The tubular bundles consist of parallel fin tubes 35 fixed in tubular plates such as 36. The condensed superheat vapor collects in chambers such as 24, 25 the latter being connected to a collector 25. A pipe 26 allows the condensate to be collected in a recipe pot 27, then this is evacuated by tubing 28.

The attachment of the superheater modules to a thin internal shell makes it possible, thanks to the flexibility thereof, to absorb the expansions and contractions resulting from temperature variations, without providing the steam supply pipes with expansion lyres or other devices special expansion compensation.

Furthermore, it allows, when one of the modules requires repair, to extract it from the separator-superheater through the O-ring manifold 21 and then the orifice 54, from which the bottom 55 which closes it is previously separated (fig. . 1), independently of the other modules.

The superheater modules comprise at regular intervals horizontal sheets 34 fixed on either side to the vertical sheets 51 (FIG. 4) themselves fixed by vertical angles 52 to the internal ferrule 30.

The bundle tubes pass through orifices with a certain clearance through the horizontal sheets 34, which divide and channel the flow of steam to be overheated. This crosses the tubular bundles such as 50, then the corresponding openings such as 53 in the internal shell 30, and arrives in the peripheral chamber 18. It is finally brought to use, for example at an expansion turbine, by tubing 19.

The separator blocks may be other than bundles of parallel corrugated sheets, and may consist, for example, of grids, successive baffles, etc. Tubular overheating bundles may not have fins or be provided with other auxiliary elements for improving the heat exchange coefficient. The number of these beams can be different from four.

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4 sheets of drawings

Claims (5)

625869 1. Vertical steam separator-superheater, comprising a lower part inside a common ferrule (3) forming a separation zone and an upper part (4) forming an overheating zone, the superheating zone comprising an axial zone (15) for the arrival of dry steam, tubular bundles of superheating (16,17) arranged in envelopes distributed around of the central zone, and a peripheral zone (18) for collecting the superheated steam, characterized in that the envelopes (16,17) of the tubular superheating bundles are fixed to a flexible ferrule (30) fixed itself to the upper part (31) of the common ferrule. 2. Separator-superheater according to claim 1, characterized in that it comprises at its upper end a toroidal manifold (21) for supplying superheating steam, connected by pipes (22) to the upper ends of the tubular superheating bundles (16, 17). 2 3. Separator-superheater according to one of claims 1 or 2, characterized in that its lower part comprises an annular chamber (5) for the admission of wet steam, connected, on the one hand, to openings (4A) for introducing wet steam, arranged so as to impart a vortex movement to this steam, and, on the other hand, from below, at the bottom of an axial zone provided with separators, by passages (6) printing at the steam a change of direction of about 180 °. 4. Separator-superheater according to claim 3, characterized in that the axial zone provided with separators is eccentric with respect to the common ferrule towards the side opposite to the openings for introducing wet steam (4A), so as to ensure a substantially constant vapor speed in the annular intake chamber (5). 5. Separator-superheater according to one of claims 1 to 4, characterized in that each of the tubular bundles of overheating is arranged to be removable independently of the others, and extractable by an orifice (55) of the upper part of the common ferrule.