BE1024894B1 - STORAGE AND SEPARATION SYSTEM FOR INDUSTRIAL STEAM GENERATOR - Google Patents

Abstract

Industrial steam generator (1) characterized in that: - the liquid / vapor separator (3) is in the form of a set of pipes, comprising at least one pair or set of separation bottles formed of at least one said turbulent bottle (31) and at least one so-called calm bottle (32) connected in communicating vessels by means of a lower duct (34) and an upper conduit (33) for fluid communication between said bottles ( 31, 32), an upper collector (36) being in the extension of said calm bottle (32) for evacuating steam, a lower collector (37) being connected to said turbulent bottle (31) for regulating the liquid level and supplying the liquid storage tank (4), and the liquid supply line (8) being connected to said turbulent bottle (31); the rising duct (35) for the liquid / vapor mixture is connected to said turbulent bottle (31), opening substantially tangentially at the level of the casing of the turbulent bottle (31), to make a first separation therefrom centrifugal liquid / vapor phases arriving at the inlet of the turbulent bottle (31); the upper duct (33) for fluid communication between the turbulent bottle (31) and the calm bottle (32) opens out substantially tangentially at the level of the envelope of the calm bottle (32), in order to carry out a second centrifugal separation therein liquid / vapor phases at the inlet; - The liquid storage tank (4) is in the form of a set of storage pipes.

Description

(30) Priority data:

(73) Holder (s):

COCKERILL MAINTENANCE & INGENIERIE S.A.

4100, SERAI NG

Belgium (72) Inventor (s):

BALCZUNAS Nicolas 4000 LIEGE Belgium

GALOPIN Jean-François 4250 HOLLOGNE-SUR-GEER Belgium

FRAIKIN Christian 4053 EMBOURG Belgium (54) STORAGE AND SEPARATION SYSTEM FOR INDUSTRIAL STEAM GENERATOR (57) Industrial steam generator (1) characterized in that: - the liquid / vapor separator (3) is in the form of a set of pipes, comprising at least one pair or set of separation bottles formed by at least one so-called turbulent bottle (31) and at least one so-called calm bottle (32) connected in communicating vessels using a lower duct (34) and an upper duct (33) for fluid communication between said bottles (31, 32), an upper manifold (36) lying in the extension of said calm bottle (32) for discharging the vapor, a lower manifold (37) being connected to said turbulent bottle (31) for regulating the liquid level and supplying the liquid storage tank (4), and the liquid supply duct (8) being connected to said turbu bottle slow (31); - the riser (35) for the liquid / vapor mixture is connected to said turbulent bottle (31), opening substantially tangentially at the level of the casing of the turbulent bottle (31), to make a first separation therein centrifuge of the liquid / vapor phases arriving at the inlet of the turbulent bottle (31); - The upper conduit (33) for fluid communication between the turbulent bottle (31) and the calm bottle (32) opens out substantially tangentially at the level of the envelope of the calm bottle (32), in order to carry out a second centrifugal separation therein liquid / vapor input phases; - the liquid storage tank (4) is in the form of a set of storage pipes.

FIG. 2

BELGIAN INVENTION PATENT

FPS Economy, SMEs, Middle Classes & Energy

Publication number: 1024894 Deposit number: BE2017 / 5189

Intellectual Property Office International Classification: F22B 37/26 F22B 37/32 Date of issue: 08/08/2018

The Minister of the Economy,

Having regard to the Paris Convention of March 20, 1883 for the Protection of Industrial Property;

Considering the law of March 28, 1984 on patents for invention, article 22, for patent applications introduced before September 22, 2014;

Given Title 1 “Patents for invention” of Book XI of the Code of Economic Law, article XI.24, for patent applications introduced from September 22, 2014;

Having regard to the Royal Decree of 2 December 1986 relating to the request, the issue and the maintenance in force of invention patents, article 28;

Given the patent application received by the Intellectual Property Office on March 22, 2017.

Whereas for patent applications falling within the scope of Title 1, Book XI of the Code of Economic Law (hereinafter CDE), in accordance with article XI. 19, §4, paragraph 2, of the CDE, if the patent application has been the subject of a search report mentioning a lack of unity of invention within the meaning of the §ler of article XI.19 cited above and in the event that the applicant does not limit or file a divisional application in accordance with the results of the search report, the granted patent will be limited to the claims for which the search report has been drawn up.

Stopped :

First article. - It is issued to

COCKERILL MAINTENANCE & INGENIERIE S.A., Avenue Greiner 1, 4100 SERAING Belgium;

represented by

PRONOVEM - Office Van Malderen, Zénobe Gramme business park (building K) - Square des Conduites d'eau 1-2, 4020, LIEGE;

a 20-year Belgian invention patent, subject to the payment of the annual fees referred to in article XI.48, §1 of the Code of Economic Law, for: STORAGE AND SEPARATION SYSTEM FOR

INDUSTRIAL STEAM GENERATOR.

INVENTOR (S):

BALCZUNAS Nicolas, Avenue Constantin de Gerlache 54, 4000, LIEGE;

GALOPIN Jean-François, Rue du Manil 3, 4250, HOLLOGNE-SUR-GEER;

FRAIKIN Christian, Voie de Liège 14, 4053, EMBOURG;

PRIORITY (S):

DIVISION:

divided from the basic application: filing date of the basic application:

Article 2. - This patent is granted without prior examination of the patentability of the invention, without guarantee of the merit of the invention or of the accuracy of the description thereof and at the risk and peril of the applicant (s) ( s).

Brussels, 08/07/2018, By special delegation:

BE2017 / 5189

STORAGE AND SEPARATION SYSTEM FOR A GENERATOR

INDUSTRIAL STEAM

OBJECT OF THE INVENTION The present invention relates to the field of water / steam separation and water storage devices included in boilers used for example in the sector of power plants or process industries, and which are subject to frequent and rapid starts with high operating pressures.

The invention generally applies to circulation boilers, whether natural circulation or forced circulation, that is to say with a pump located in the circulation loop of the evaporator.

In particular, the present invention relates to boilers available horizontally or vertically of the steam generator type with heat recovery or HRSG (for heat recovery steam generator).

Technological background and state of the art In a conventional configuration of a prior art boiler, the water / steam separation function is often provided by a cylindrical tank called a "separator tank". This balloon is supplied with water by a supply water pipe which contains a control valve. According to the principle of natural circulation, the water then flows from the balloon to a

BE2017 / 5189 evaporator via downcomers, then go back up into the tubes of this evaporator and be at least partially evaporated there. The water / steam mixture is returned to the flask by the water riser tubes (risers) so that the two phases (water / steam) can be separated there, possibly by means of one or more suitable devices or methods, known in itself of the skilled person. The level of the water level in the tank is controlled by the aforementioned control valve. The saturated steam above the water tank of the balloon escapes from the balloon through a base provided for this purpose and is directed to the steam network via the superheaters (if applicable), to then supply the process or the steam turbine. using the steam produced. The tank also has a water storage function in the event of a breakdown in the food pumps that supply it.

The volume of the balloon must be sufficient for a flow time (ROT) and a swelling effect required by the specifications. These two notions can be defined as follows:

- “run-out time” (ROT), “holding time” or run-off time: duration defined contractually in the specifications which corresponds to the duration during which the balloon must be able to operate without being supplied with water by the feed pumps;

- "swell effect" or swelling effect: before starting the boiler, the evaporator is filled with water. When this water heats up and reaches boiling point, a large volume of water is pushed to the flask and replaced in the evaporator tubes with steam. The tank must be sized to be able to accommodate this volume of water, making sure not to overflow towards the superheaters. This phenomenon can also occur during certain load transients.

Currently, the development of the energy market requires greater flexibility of the production units, with ever higher operating pressures. As the vapor pressures demanded in such types of devices continue to increase, this therefore results in the need to provide large thicknesses at the pressure parts. In addition, when they are subjected to large gradients

BE2017 / 5189 temperature rise, these parts of the installation may suffer mechanical damage due to the phenomenon of fatigue given the stresses settling in the thickness of the material when the temperature is not homogeneous within it (transient thermal).

[0008] Thus, as the context of renewable energies generates a cyclic operation of the boilers and requires a higher number of stops / starts over the lifetime of the installation, the current installations must be able to start very quickly, and at increasingly shorter time intervals. As a result, the temperature rise gradients during start-ups are higher and cause the components whose number of fatigue cycles increases to suffer.

In this context, the type of conventional high pressure separator tank boiler has many drawbacks. It is recognized in the prior art that the separation balloon is one of the critical points from the point of view of fatigue. This is due to the fact that it is often the pressure component with the thickest wall in the installation and that, moreover, there are relatively large temperature rise gradients compared to the rest of the installation.

On the other hand, the supply times for thick sheets are a point of attention in the management of the planning of a project. In some extreme cases, a problem of bending capacity of thick ferrules can even arise (around 150 mm thick).

A simple solution proposed in several documents to reduce the problems of fatigue of high pressure balloons is to replace the conventional single balloon with two containers of smaller volume. Indeed, two balloons then share the functionality of total storage and separation capacity of the classic “single balloon” solution, and are therefore thinner and less critical from the point of view of mechanical fatigue.

Document WO 2012/148656 A1 relates to an evaporator comprising two cylindrical flasks, situated in height at slightly different levels, namely a lower storage flask and an upper separation flask that can also function as a storage flask.

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The two flasks are smaller than a traditional "single flask" for an evaporator of similar capacity, which reduces the pressure on the walls which can therefore be thinner. The water is brought into the lower storage tank and then flows to the evaporator by downcomers. The water / vapor mixture leaving the evaporator is conveyed by risers in the separation flask comprising devices for aiding the water / vapor separation. The two tanks are connected by a drain pipe and by a drain pipe.

The system proposed by document WO 2013/083684 A1 includes an evaporator, a water tank in fluid communication with the evaporator, the water tank being located upstream of the evaporator, and a first storage tank. vapor in fluid communication with the evaporator, the first vapor balloon being located downstream of the evaporator. The water tank operates to supply feed water to the evaporator, while maintaining a predetermined water level in the first steam tank. In this way, the balloon and the tank share the functions of storage capacity and separation of the classic "single balloon".

Document WO 2012/129195 A2 relates to a heat recovery steam generator which comprises a first balloon intended to receive a water / steam mixture coming from an evaporator. This first balloon transmits the water / steam flow received from the evaporator to a second balloon which will separate the steam from the water / steam mixture. An outlet is provided in the second balloon to release the separated vapor.

The heat recovery steam generator of document US 2005/0087151 A1 also provides a solution for reducing the diameter, and therefore the thickness, of the balloon in order to reduce the temperature gradient across its wall at start-up. This makes it possible to limit the thermal fatigue of the balloon as well as the wear thereof. The reduction in balloon thickness also reduces the manufacturing cost. This document discloses a water / steam separator comprising a horizontal balloon carrying out a first separation of the water / steam mixture coming from the heat exchanger. The remaining water is returned to the heat exchanger, while the

BE2017 / 5189 steam is brought to a second vertical tank, allowing drying of the steam (second separation). The dry steam is discharged, while the water is returned to the horizontal tank.

Document WO 2014/028107 A2 discloses a vertical evaporator, the water / vapor mixture of which is brought to the vertical separator by risers (“risers”). The separation is carried out by centrifugation in the separator, to give rise to steam escaping through an upper duct, and water flowing in an outlet duct (“downcomers”) in order to be reused in the evaporator.

Finally, the Applicant has also proposed a solution to the above problem thanks to the concept of "double drum". Document WO 2016/079120 A1 relates to a heat recovery steam generator having two balloons. A storage tank providing a storage function supplies an overflow to a second tank, which will also fulfill the storage functionality of separating the liquid water / vapor phases. Despite its advantages in terms of fatigue reduction and the need for thinner ferrules, as discussed above, this solution has disadvantages such as a higher weight and therefore a higher manufacturing cost in the case of two balloons (despite the fact that the tanks are smaller), greater complexity or criticality of the water level control in the transient phases (via in particular the presence of a second control valve compared to the prior art) and finally an increase in size.

AIMS OF THE INVENTION The present invention aims to provide a solution for steam generators subjected to frequent and rapid starts with high operating pressures.

In particular, the invention aims to improve the fatigue strength of the water / vapor separator and other components under pressure, in particular by reducing their thicknesses, the challenge being an increase in the service life of this equipment.

BE2017 / 5189 Another object of the invention is to avoid the presence of an additional control valve compared to the situation of a single separator tank.

Yet another object of the invention is to ensure the integration of the new concept in a "balloon" platform environment without fundamental changes in the frame, the neighboring piping and existing platforms.

Yet another object of the invention is to reduce the cost of the installation and to facilitate the supply of materials used for the design thanks to a simplified drawing, and in particular by working as much as possible with components available in trade (and not made to order).

Main characteristic features of the invention A first aspect of the present invention relates to an industrial steam generator comprising:

- an evaporator,

- a liquid supply pipe, fitted with a control valve,

- a liquid / vapor separator and a liquid storage tank in fluid communication with the liquid / vapor separator;

- a riser for the liquid / vapor mixture between an outlet of the evaporator and the liquid / vapor separator;

- a downspout for the return of the liquid between the separator or the storage tank and an inlet to the evaporator, characterized in that:

- the liquid / vapor separator is in the form of a set of pipes, comprising at least one pair or set of separation bottles formed by at least one so-called turbulent bottle and at least one so-called calm bottle connected in vases communicating using a lower conduit and an upper fluid communication conduit between

BE2017 / 5189 said bottles, an upper collector being in the extension of said calm bottle for evacuating the vapor, a lower collector being connected to said turbulent bottle for regulating the level of liquid and supplying the liquid storage tank, and the conduit liquid supply being connected to said turbulent bottle;

- the riser for the liquid / vapor mixture is connected to said turbulent bottle, opening substantially tangentially at the level of the casing of the turbulent bottle, in order to carry out a first centrifugal separation of the liquid / vapor phases arriving at the 'entry of the turbulent bottle;

- The upper fluid communication duct between the turbulent bottle and the calm bottle opens out substantially tangentially at the level of the envelope of the calm bottle, in order to carry out a second centrifugal separation of the liquid / vapor phases at the inlet;

- the liquid storage tank is in the form of a set of storage pipes.

According to preferred embodiments of the invention, the steam generator further comprises one of the following characteristics or an appropriate combination of the following characteristics:

- the liquid / vapor separator comprises at least two pairs of turbulent and calm bottles, the upper collector connecting the calm bottles so that the calm bottles of the different couples communicate by communicating vessels to balance the pressures between the couples of separation bottles and the lower manifold connecting the turbulent bottles so that the turbulent bottles of the different couples communicate by communicating vessels to balance the liquid levels between the pairs of separation bottles;

the liquid storage tank comprises a plurality of vertical conduits all connected at their upper part by an upper storage collector and at their lower part by a lower storage collector;

BE2017 / 5189

- the downpipe connects all the pipes of the storage tank to an inlet of the evaporator;

- The liquid storage tank comprises at least two groups of pipes arranged on either side or symmetrically with respect to the evaporator;

- the liquid storage tank is entirely located below the level of the lower collector of the liquid / vapor separator;

- the entire storage tank piping is completely filled during normal operation;

- the downpipe connects the lower storage manifold of the liquid storage tank to an inlet of the evaporator;

- the liquid storage tank is generally located at the same level as the liquid / vapor separator;

- the liquid storage tank is arranged all around the liquid / vapor separator;

- The lower collector of the liquid / vapor separator is located at the same level as the lower storage collector of the liquid storage tank and in fluid communication with it;

- the set of pipes of the storage tank is not completely filled in normal operation, the filling level regulated by the corresponding control valve, by the play of communicating vessels, at a level located between the tangential connection of the mounted on the turbulent bottle and the lower connection between turbulent bottle and still bottle;

- the downpipe connects the lower manifold of the liquid / vapor separator to an inlet of the evaporator.

A second aspect of the present invention relates to a method for generating a high pressure steam cycle by means of an industrial steam generator in natural or forced circulation as described above, in normal operation, it that is to say when the water level in the separation bottles is above a predetermined critical threshold, and so as to ensure a required flow time or ROT, comprising at least the following steps:

BE2017 / 5189

i) all the pipes of the storage tank are filled to a maximum level determined via the liquid supply pipe, regulated by the control valve;

ii) the turbulent separation bottle is supplied with a liquid / vapor mixture via the evaporator and the ascent pipe;

iii) the two liquid / vapor phases undergo a first centrifugal separation into liquid and wet vapor in the turbulent separation bottle;

iv) the humid vapor escapes from the turbulent separation bottle towards the inlet of the calm separation bottle through the upper duct;

v) the wet vapor undergoes a second centrifugal separation into liquid and dry vapor in the calm separation bottle;

vi) the vapor phase is evacuated from the still bottle by the upper manifold for use, and the liquid phase is sent to the turbulent bottle through the lower duct;

vii) the liquid in the turbulent bottle flows naturally into the lower collector of the liquid / vapor separator.

Advantageously, the method for generating a high pressure steam cycle by means of an industrial steam generator in natural or forced circulation as described above, comprises, in the start-up phase, at least the steps described, but where step i) is replaced by the following step:

i) the pipes of the storage tank are filled to a level lower than said maximum level called "starting".

Again advantageously, the method for generating a high pressure steam cycle by means of an industrial steam generator in natural or forced circulation as described above, in particular or degraded operation, that is to say when the water level in the separation bottles is below a predetermined critical threshold, comprises at least the steps described, but where step ii) is replaced by the following step:

BE2017 / 5189 ii) the control valve is closed and all of the storage tank piping supplies the steam generator evaporator, the volume of the storage tank thus contributing to ensuring the ROT required by communicating vessels.

Brief Description of the Figures [0029] Figure 1 schematically shows a general perspective view of a first embodiment of the steam generator according to the present invention.

FIG. 2 represents a first detailed view corresponding to the steam generator according to FIG. 1.

FIG. 3 represents a second detailed view corresponding to the steam generator according to FIG. 1.

Figure 4 schematically shows a perspective view of the first embodiment of the steam generator according to the present invention, integrated into a real project (platforms, frame, routing of pipes).

Figure 5 schematically shows a second embodiment of the steam generator according to the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION The general principle of the solution proposed in the context of the present invention is to replace the prior art separation and storage tanks as much as possible with piping. commercially available. Tubing will be understood, in the following description, any set of pipes, tubes, drains or conduits, generally of circular section and suitable for the flow of a fluid such as a liquid or a gas.

The storage volume corresponding to these pipes must however be sufficient only to, on the one hand, ensure a flow time

BE2017 / 5189 (ROT) imposed and, on the other hand, accommodate the swelling effect (swell effect) during start-up or load transients.

In each of the new configurations relating to the improvement proposed according to the invention, two types of piping must be distinguished: a set of storage pipes and a set of pipes performing the water / vapor separation.

As illustrated in FIG.1, according to a first embodiment of the invention, on the one hand, the "classic" balloon of the prior art performing the water / vapor separation in the case of a evaporator 2 of a steam generator 1 is replaced by a first set of separation pipes or conduits 3. This set 3 is located approximately at the place where the separator balloon of the prior art is currently located (especially in the case of the improvement of a preexisting installation).

On the other hand, the prior art storage tank (see previous documents above) is replaced by at least one, and preferably two sets of pipes or conduits 4 for storage.

The set of separation pipes 3 comprises a plurality of pairs of bottles 31, 32 consisting on the one hand of a bottle 31 called "turbulent" connected to a bottle 32 called "calm". In the embodiment shown in FIG. 1 and FIG. 2, two modules of two pairs of turbulent / calm bottles are represented, ie 8 bottles in total. The principle of the invention is thus to operate thanks to couples of turbulent / calm bottles, which can effectively be multiplied as many times as desired. In the context of the present invention, the term “bottle” means any metal container of elongated shape, generally cylindrical and which is intended to contain a fluid such as a water-steam mixture conveyed or evacuated by at least one inlet pipe and at least outlet piping.

For questions of speed criterion to be satisfied which requires a decoupling between the flows concerning the two types of bottle, one could be led, according to the invention, to connect "x" turbulent bottles to "y" calm bottles with x may possibly be different from y, respectively x may be greater than y, x may be smaller than y

BE2017 / 5189 or x can be equal to y (x, y = 1,2, 3, ...). In the example of execution described so far, x and y are equal to 1, that is to say that a calm bottle is connected to a turbulent bottle. In certain calculations, the inventors had to consider, for example, making the flow of two turbulent bottles converge towards a common calm bottle. In another example, we could conceptually consider dividing the flow leaving a turbulent bottle to send it to two calm bottles, etc.

The two bottles 31, 32 operate, that is to say fill or empty, according to the principle of communicating vessels and are connected, within the same couple, by an upper conduit 33 and a conduit lower 34 allowing respectively the passage of steam and water.

Feed water inlet conduits 35 (“risers”) connect the evaporator 2 to each turbulent bottle 31 in order to supply it with a water / vapor mixture leaving the evaporator. These conduits 35 are each connected to the turbulent bottle 31 in a substantially tangential manner. In this way, the mixture enters the turbulent bottle 31 tangentially to the cylindrical periphery of the bottle so that the liquid / vapor phases of the mixture can be separated by centrifugation (principle of the cyclonic separator). Indeed, a vortex is created in the bottle, which leads to a turbulent flow. Consequently, the vapor is found localized in the center of the turbulent bottle 31 while the water is pushed or pressed against the walls of the latter and will descend along the walls by gravity. A first separation therefore takes place in this turbulent bottle 31.

The upper conduit 33 then allows the passage of steam from the turbulent bottle 31 to the still bottle 32 for a second phase separation preferably also by centrifugation. The calm bottle 32 therefore makes it possible to obtain optimum drying of the vapor separated in the turbulent bottle 31. Advantageously therefore, the upper conduit 33 also connects tangentially to the cylindrical periphery of the calm bottle 32. There is therefore, according to the invention, two centrifugations in series to ensure

BE2017 / 5189 the separation of the liquid and vapor phases, by exploiting the density difference between water and vapor.

Among the secondary advantages of this second bottle are the drying of the vapor without use or with limitation of the anti-fog devices (“demisters”), an easier measurement of the water level, as well as better security, given that the mixture is less agitated than in the first bottle 31.

The lower conduit 34, as well as a drain 38, allow the passage of water between the two bottles 31, 32.

The separation installation 3 further comprises separation collectors, respectively upper 36 and lower 37. The upper collector 36 connects the calm bottles 32 together, at an upper end thereof, which allows to balance the pressure between the different pairs of separation bottles, and also evacuates the steam so that it is sent, for example to superheaters for its use. The lower manifold 37 connects the turbulent bottles 31 of the installation, at a lower end thereof. This makes it possible to balance the water levels in these turbulent bottles 31 which are connected in communicating vessels. Bottle water naturally flows to this lower collector.

Before returning to the exchanger, the water is first stored in a set of pipes or storage conduits 4, which are supplied by the lower manifold 37 of the separation system 3. This set of storage conduits 4 replaces the prior art storage tank (see prior art above) and will be located for example on each side of the steam generator.

As shown in FIG. 3, according to an exemplary embodiment, the set of storage conduits 4 comprises vertical parallel conduits 41 connected by an upper storage collector 42 and a lower storage collector 43.

BE2017 / 5189 The upper storage collector 42 is in communication with the lower separation collector 37 and the lower storage collector with a downcomer 5 for the return of water to an inlet of the evaporator by natural circulation. The downcomer 5 is shown in the figures radially with respect to the evaporator 2.

Preferably, the set of storage conduits will be in the form of two groups of conduits 4, symmetrical with respect to the evaporator 2, as shown in the example of FIG. 1.

This set of storage conduits 4 is intended to retain a certain volume, in this first embodiment of the invention, and is completely filled with water in normal operation, thus defining a "maximum volume »Storage. Thus, in the event of a problem with the supply of the abovementioned bottles 31, 32, the storage volume is used to slow the drop in the level of water in the installation.

In this embodiment, the supply line (not shown) can be connected to part of the tank 4, or alternatively to part of the separation zone 3, or, in general, to any appropriate place in the system.

In addition, a feed water control valve (not shown) is actuated to regulate a water level which is suitably located, in normal operating mode, between the tangential connection of the risers 35 on the turbulent bottles 31 and the bottom connection 34 between turbulent bottles 31 and calm 32. The water level is identical in all of the bottles since they are connected in communicating vessels.

In transient operation, if the water level drops by a lack of water supply to the system, in the case of breakdown of the pumps for example, the storage volume included in all of the storage pipes 4 will contribute then to ensure a sufficient ROT.

Furthermore, during start-up, the water level will be defined at a lower level in the storage pipes (called "start-up level"), for example at the height of the lower storage collector 43.

BE2017 / 5189

This low position of the water level at startup makes it possible to contain a certain volume of swelling overflowing in the turbulent bottles 31 and which will therefore flow naturally towards the storage areas 4 initially not filled with water. This phenomenon is then anticipated thanks to a lower water level compared to normal operation.

In the embodiment presented above, the storage and separation pipes are mainly arranged vertically. This has certain advantages, such as easier evaporation. In addition, still advantageously, the relationship between the variation in volume and water level in the pipes and bottles is linear, which gives an advantage in terms of ease of control.

FIG. 4 represents the concept of separation and storage system according to the invention integrated into the 3D model of a real steam generator project, without modification at the level of existing platforms, the existing metal framework and the routing of large bore pipes.

FIG. 5 illustrates a second embodiment of the invention. The principle is identical to the first form of execution, except for a few differences. In this case, the set of storage pipes 4 is generally at the same level as the set of separator pipes 3, that is to say that the average height of the separation system 3 is substantially equal to the average tank height 4.

All vertical pipes are in communicating vessels. On the other hand, the water descent conduits 5 no longer start from the set of storage pipes towards an inlet of the evaporator 2, but start from a lower manifold 37 of the separation system 3.

The fact that the storage and separation pipes are generally at the same level implies a particular advantage, namely the definition of a water level plane common to the entire system and whose total area on the The whole system is increased compared to the first embodiment above. This in turn brings two consequences: controlling the water level will be less critical and the amount of material

BE2017 / 5189 necessary to contain the same storage volume will increase. In fact, the storage areas are no longer completely submerged in this case, unlike the FIG installation. 1. Therefore, the "maximum volume" of storage is smaller than the total volume of the storage piping. This somehow decreases the optimization of the weights.

In addition, compared to the first embodiment, the second embodiment above has the advantage of having only one compact set of pipes (separator and storage tank), more easy to transport and assemble on site.

The main advantage of the invention, whether according to the first or the second embodiment, is the use of a set of pipes making it possible to avoid the use of balloons. Thanks to this, the thicknesses of the components of the installation are thinner and this generates less fatigue. In addition, the schedule for prefabrication of these elements is simplified, with reduced delivery times, given the absence of ferrules and other very thick parts. On the other hand, the additional valve used for the "double drums" of the prior art is avoided, which makes the system more passive and easier to maintain. Furthermore, the system of the invention can be easily integrated into a conventional boiler without having to modify the frame, the pipes, etc.

Compared to the stagnation of water, the two embodiments described prevent water from stagnating by judicious dimensioning rules specific to each of the two solutions. For the first embodiment, it is the dimensioning of vertical pipes of the tank 4 which ensures that the pressure difference is sufficiently low in these pipes in parallel so that the water passes through the entire system avoiding zones dead. For the second embodiment, it is the fact of correctly positioning the height of the water supply 8 on the storage bottles (in addition to the fact that each of the storage bottles is actually supplied) which prevents stagnation of the 'water.

From the principle of the invention may arise the following alternatives and generalizations:

2017/5189

BE2017 / 5189

- the principle of the proposed improvement is independent of the type of boiler considered: vertical, horizontal or mixed HRSG;

- the number of pairs of turbulent / calm bottles can be multiplied;

- the principle of the proposed improvement is independent of the methods and equipment used to carry out the separation of the water / steam phases as well as the drying of the steam.

2017/5189

List of reference symbols steam generator evaporator set of separation ducts set of storage ducts downcomer duct low pressure balloon frame supply line turbulent bottle calm bottle upper duct connecting turbulent bottle and bottle clamp lower duct connecting turbulent bottle and bottle claims riser (upper riser) upper separation collector lower separation collector drain storage duct upper storage collector lower storage collector

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Claims (16)

1. Industrial steam generator (1) comprising: - an evaporator (2), - a liquid supply pipe (8), fitted with a control valve, - a liquid / vapor separator (3) and a liquid storage tank (4) in fluid communication with the liquid / vapor separator (3); - a rise pipe (35) for the liquid / vapor mixture between an outlet of the evaporator (2) and the liquid / vapor separator (3); - a downpipe (5) for the return of the liquid between the separator (3) or the storage tank (4) and an inlet of the evaporator (2), characterized in that: - the liquid / vapor separator (3) is in the form of a set of pipes, comprising at least one pair or set of separation bottles formed by at least one so-called turbulent bottle (31) and at least one so-called calm bottle (32) connected in communicating vessels using a lower conduit (34) and an upper conduit (33) for fluid communication between said bottles (31, 32), an upper collector (36) is located in the extension of said calm bottle (32) for discharging the vapor, a lower collector (37) being connected to said turbulent bottle (31) for regulating the level of liquid and supplying the liquid storage tank (4), and the liquid supply conduit (8) being connected to said turbulent bottle (31); - the riser (35) for the liquid / vapor mixture is connected to said turbulent bottle (31), opening substantially tangentially at the level of the casing of the turbulent bottle (31), to make a first separation therein centrifuge of the liquid / vapor phases arriving at the inlet of the turbulent bottle (31); - The upper conduit (33) for fluid communication between the turbulent bottle (31) and the still bottle (32) opens out substantially tangentially at the level of the envelope of the bottle BE2017 / 5189 calm (32), to perform a second centrifugal separation of the liquid / vapor phases at the inlet; - the liquid storage tank (4) is in the form of a set of storage pipes. 2. Steam generator according to claim 1, characterized in that the liquid / vapor separator (3) comprises at least two pairs of turbulent (31) and calm (32) bottles, the upper collector (36) connecting the calm bottles ( 32) so that the calm bottles (32) of the different couples communicate by communicating vessels to balance the pressures between the pairs of separation bottles (31, 32) and the lower manifold (37) connecting the turbulent bottles (31) so that the turbulent bottles (31) of the different couples communicate by communicating vessels to balance the liquid levels between the couples of separation bottles (31, 32). 3. Steam generator according to claim 1, characterized in that the liquid storage tank (4) comprises a plurality of vertical conduits (41) all connected to their upper part by an upper storage collector (42) and to their lower part by a lower storage collector (43). 4. Steam generator according to claim 3, characterized in that the downpipe (5) connects all of the pipes of the storage tank (4) to an inlet of the evaporator (2). 5. Steam generator according to claim 1, characterized in that the liquid storage tank (4) comprises at least two groups of pipes arranged on either side or symmetrically with respect to the evaporator (2). 6. Steam generator according to claim 1, characterized in that the liquid storage tank (4) is entirely located below the level of the lower collector (37) of the liquid / vapor separator (3). 7. Steam generator according to claim 6, characterized in that the set of pipes of the storage tank (4) is completely filled during normal operation. BE2017 / 5189 8. Steam generator according to claim 3, characterized in that the downpipe (5) connects the lower storage manifold (43) of the liquid storage tank (4) to an inlet of the evaporator (2). 9. Steam generator according to claim 1, characterized in that the liquid storage tank (4) is generally located at the same level as the liquid / vapor separator (3). 10. Steam generator according to claim 9, characterized in that the liquid storage tank (4) is arranged all around the liquid / vapor separator (3). 11. Steam generator according to claim 9, characterized in that the lower collector (37) of the liquid / vapor separator (3) is situated at the same level as the lower storage collector (43) of the liquid storage tank (4 ) and in fluid communication with it. 12. Steam generator according to claim 9, characterized in that the set of pipes of the storage tank (4) is not completely filled in normal operation, the filling level regulated by the corresponding control valve, by the set of communicating vessels, at a level located between the tangential connection of the riser (35) on the turbulent bottle (31) and the lower connection (34) between turbulent bottle (31) and still bottle (32). 13. Steam generator according to claim 11, characterized in that the downpipe (5) connects the lower manifold (37) of the liquid / vapor separator (3) to an inlet of the evaporator (2). 14. Method for generating a high pressure steam cycle by means of an industrial steam generator in natural or forced circulation according to any one of claims 1 to 13, in normal operation, that is to say when the water level in the separation bottles (31, 32) is above a predetermined critical threshold, and so as to ensure a required flow time or ROT, comprising at least the following steps: i) all the pipes of the storage tank (4) are filled to a maximum level determined via the liquid supply pipe (8), regulated by the control valve; BE2017 / 5189 ii) the turbulent separation bottle (31) is supplied with a liquid / vapor mixture via the evaporator (2) and the riser (35); iii) the two liquid / vapor phases undergo a first centrifugal separation into liquid and wet vapor in the turbulent separation bottle (31); iv) the humid vapor escapes from the turbulent separation bottle (31) towards the inlet of the calm separation bottle (32) through the upper duct (33); v) the wet steam undergoes a second centrifugal separation into liquid and dry steam in the calm separation bottle (32); vi) the vapor phase is evacuated from the still bottle (32) through the upper manifold (36) for use, and the liquid phase is sent to the turbulent bottle (31) through the lower conduit (34); vii) the liquid in the turbulent bottle (31) flows naturally into the lower collector (37) of the liquid / vapor separator (3). 15. A method for generating a high pressure steam cycle by means of an industrial steam generator in natural or forced circulation according to any one of claims 1 to 13, comprising, in the start-up phase, at least the steps according to the claim 14, but where step i) is replaced by the following step: i) the pipes of the storage tank (4) are filled to a level lower than said maximum level known as “starting”. 16. Method for generating a high pressure steam cycle by means of an industrial steam generator in natural or forced circulation according to any one of claims 1 to 13, in particular or degraded operation, that is to say when the water level in the separation bottles is below a predetermined critical threshold, comprising at least the steps according to claim 14 or 15, but where step ii) is replaced by the following step: ii) the control valve is closed and all the pipes of the storage tank (4) feed the evaporator (2) of the steam generator (1), the 2017/5189 2 3 BE2017 / 5189 volume of the storage tank thus contributing to ensuring the ROT required by communicating vessels. BE2017 / 5189