DE1251336B - Steam generator with reheating - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

int. Cl .:

F 22 g

German class: 13 d-9/03

Number: 1 251 336

File number: S 94055 I a / 13 d

Filing date: November 5, 1964

Open date: October 5, 1967

The invention relates to a steam generator with reheating in a multi-stage Engine partially expanded steam, with one arranged in the steam generator between heating surfaces Heat exchanger through which high pressure steam and partially expanded steam flows and with a bypass line which bypasses the heat exchanger and has a throttle element for high pressure steam.

In the known steam generators of this type, the bypass line only bridges the heat exchanger.

The invention is based on the object of using simple means a steam generator of the initially to create the mentioned genus with improved operability compared to the known order, whereby under operability both the operational safety and the controllability of the steam generator is to be understood.

The invention is characterized in that the bypass line apart from the heat exchanger at least bypasses part of a heating surface for high pressure steam.

The invention compared to the known arrangement in which the bypass line only bridged the heat exchanger, achieved considerable advantages. Either you can with the invention Arrangement make the throttle valve smaller than in the known arrangement. Or it will - with the same size throttle body - the control range is enlarged compared to the known arrangement, d. This means that the largest possible partial quantity that can be passed through the bypass line is larger will be throttled without the flow of high pressure steam passed through the heat exchanger got to. In addition to this better controllability, there is also greater operational reliability in that the Point at which the two high-pressure steam flows reunite, no significant temperature deviations arise between these currents. It will take the place of the confluence of the two partial flows practically no thermal stresses, and there is the temperature distribution in the heating surface pipes connected in parallel behind the confluence.

According to an advantageous embodiment of the invention, the bypass line is bypassed Heating surface for high pressure steam arranged in the direction of flow behind the heat exchanger.

The amount of high-pressure steam flowing through the bypass line is expediently by means of Steam generator with reheating

Applicant:

Sulzer Brothers Aktiengesellschaft, Winterthur

(Switzerland)

Representative:

Dipl.-Ing. H. Marsch, patent attorney,

Düsseldorf, Lindemannstr. 31

Named as inventor:

Richard Litwinoff, Winterthur (Switzerland)

Claimed priority:

Switzerland of October 29, 1964 (13 976)

of the throttle element in the bypass line in a manner known per se as a function of the temperature of the reheated steam flowing to the low-pressure part of the engine is set. This is a temperature sensor connected to the line leading to the low pressure part, the z. B. over a Regulator acts on the throttle body.

In order to further improve the control of the reheating temperature, this temperature sensor at the same time with a cooler, e.g. B. an injection cooler, are in operative connection behind or in a manner known per se before the bypass line branches off into the high-pressure steam flow is switched on.

The controllability of the steam generator is still possible according to a further embodiment of the invention improved by the fact that in a manner known per se leading to the high pressure steam to the engine A temperature sensor is connected to the line, which measures the amount of coolant behind the confluence of the bypass line in the high-pressure steam flow switched on cooler changed.

It also serves to improve the controllability of the system if, according to a further embodiment of the invention in a manner known per se to the heat exchanger at least one flue gas heated Reheater heating surface is connected, which is preferably in the flow direction of the partially expanded Steam is behind the heat exchanger.

709 650/141

Two exemplary embodiments of the invention are illustrated in the following description with reference to the drawing explained. It shows

1 shows a schematic representation of a once-through steam generator according to the invention,

F i g. 2 shows another embodiment of a part of the steam generator according to FIG. 1.

According to FIG. 1 feed water is fed to the steam generator 2 by means of a feed pump 1, which first an economizer heating surface 3 flows through, which by way of the flue gas flow indicated by an arrow 4 is arranged in the rear part of the steam generator. Arrived from the economizer heating surface 3 the working fluid to an evaporator heating surface 5 in the area of the furnace 6 in the steam generator arranged and .predominantly heated by radiation. The resulting in the evaporator heating surface Steam-water mixture reaches a separator 7, in which the mixture is divided into water and Steam is separated. While the water flows through a valve 8, which is influenced by the level in the separator 7 is drained, the steam flows into a first superheater heating surface 9 and from there via a line 10. in a heat exchanger 11, which apart from the high pressure steam from the heating surface 9 also from partially expanded steam from the high pressure part 12 of a multi-stage turbine system is flowed through. The high-pressure steam flows from the heat exchanger 11 through a second superheater heating surface 13 and then via a line 14 into a final superheater heating surface 15, from where it is via a line 16 into the High pressure part 12 arrives. The partially expanded steam coming from the heat exchanger 11 flows through it a flue gas heated reheater heating surface 17, which is in the flue gas flow between the second superheater heating surface 13 and the end superheater heating surface 15 is arranged and which has a Line 18 is connected to the low-pressure part 19 of the turbine system.

The one between the first and second superheater heating surfaces 9 or 13 arranged in the steam generator heat exchanger 11 is made of nested Tubes constructed, of which the inner tube 20 carries the high pressure steam, during the Annular space between the pipe 20 and the jacket pipe 21 flowed through by partially expanded steam will. The heat exchanger 11 and the second superheater heating surface 13 are through a bypass line 22 bypassed by connecting the lines 10 and 14 directly to one another. In the bypass line 22, a throttle member 23 is provided, which via a controller 25 with a temperature sensor 24 in Connection is connected to the conduit 18 carrying reheated steam. Of the In this example, temperature sensor 24 is also located via a controller 26 with a valve 27 Compound that adjusts the amount of injection water that the high pressure steam receives before it enters the Heat exchanger 11 is supplied. A temperature sensor 30 is also connected to the high pressure part 12 of the Turbine system leading line 16 connected. The sensor 30 is via a controller 31 with a Valve 32 connected, which adjusts the amount of injection water that the high-pressure steam before its entry is fed into the end superheater heating surface 15. The heating surfaces do not have to be as drawn consist of one tube each, but in most cases they are made up of several parallel-connected Pipes be built, which is indicated by the unspecified collector and distributor is.

That which arises in the evaporator heating surface 5 and is preheated in the first superheater heating surface 9 Steam is sent to a part in the heat exchanger 11, in which it is part of its Releases overheating heat to the partially expanded steam, and to the other part in the bypass line

ίο 22 headed. This flowing through the bypass line 22 Partial amount of steam is dependent on the temperature determined by the sensor 24 temporarily superheated steam in the line 18 with the help of the throttle member 23 is set. The partially relaxed Dull becomes in the heat exchanger J1 except for the high-pressure steam from the furnace or the flue gases. The one in the heat exchanger 11 cooled high-pressure steam is further superheated in the second superheater heating surface 13 and reaches the line 14, where it meets the heat exchanger flowing through the bypass line 22 11 and the heating surface 13 subset led past combined.

To improve the temperature control by means of the throttle member 23, the temperature of the high-pressure steam influenced in line 10 by supplying a variable amount of injection water. the Temperature control acts in such a way that when the reheating temperature at the sensor 24 increases, the Injection quantity increased with the aid of valve 27 and the partial quantity of high-pressure steam flowing through bypass line 22 is also enlarged. Thus, on the one hand, the temperature of the high pressure steam before entering the heat exchanger and on the other hand that in the heat exchanger 11 acting high-pressure steam is reduced, so that the high-pressure steam on reduces the amount of heat transferred to the partially expanded steam. When the reheating temperature drops the amount of water to be injected is reduced with the aid of the valve 27 and by the Bypass line 22 reducing the amount of high-pressure steam flowing with the aid of the throttle element 23. Through this, that the bypass line 22 apart from the heat transfer

Φ5 also supports 11 the second superheater heating surface 13 bridged, there are no significant ones where the two high-pressure steam streams unite again Temperature differences on, v / eil the high pressure steam the heat that it in the heat exchanger 11 gives off the partially expanded steam, in the downstream second superheater heating surface 13 again absorbs, so that its temperature at the exit from the heating surface 13 is practically equal to the temperature of the high pressure steam in the bypass line 22 is.

Even if the heating surface bypassed by the bypass line for the high-pressure steam is in its Direction of flow is arranged upstream of the heat exchanger 11, which is also one in the drawing Not shown embodiment of the invention can be seen, occur at the point where the two Combine high pressure steam flows again, no significant temperature differences. In this In this case, the high-pressure steam that does not flow through the bypass line first enters the heat exchanger upstream heating surface, which is then transferred to the partially expanded in the heat exchanger Steam is released so that the temperature of the high-pressure steam at the outlet from the heat

Transmitter 11 practically equal to the temperature of the high pressure steam flowing through the bypass line is. In both cases, thermal stresses are avoided at the point where the bypass line opens.

The high pressure steam from the line 14 is in the final superheater heating surface 15 to its final temperature overheated, this temperature with the help of the temperature sensor 30 by supplying injection water is regulated in the line 14.

In the embodiment according to FIG. 2, the bypass line 22 is branched off at one point on the line 10, which is before the injection water is supplied. So in this case only the temperature will be of the high-pressure steam partial flow flowing into the heat exchanger 11 through the supply of the injection water influenced, while the high pressure steam flowing through the bypass line 22 thereof remains unaffected. Otherwise, the temperature control and the structure of the system are the same as in Fig. 1.

Influencing the temperature of the high pressure steam by injecting the water that is fed through the valve 27, happens in addition to the possibility of influencing with the help of Throttle element 23 in the bypass line 22. In principle, it is sufficient to influence the heat transfer in the area of the heating surfaces bypassed by the bypass line 22 - including the heat exchanger heard - if depending on the temperature determined with the temperature sensor 24 only the throttle valve 23 is influenced.

The invention is applicable not only to once-through steam generators, but also to Steam generators that work according to the natural circulation principle or the forced circulation principle.

The embodiments according to the subclaims can with the invention according to the patent claim can be combined individually or in groups of several.

Claims (8)

Patent claims: 1. Steam generator with reheating of partially expanded in a multi-stage engine Steam, with a heat exchanger arranged in the steam generator between heating surfaces, which carries high-pressure steam and is flowed through by partially expanded steam, and with a bypassing the heat exchanger, a bypass line having a throttle element for high pressure steam, characterized in that that the bypass line apart from the heat exchanger at least part of a heating surface for high pressure steam bypasses. 2. Steam generator according to claim 1, characterized in that the bypass line bypassed heating surface for high pressure steam in its flow direction behind the heat exchanger is arranged. 3. Steam generator according to claim 1, characterized in that a temperature sensor is connected in a manner known per se to the reheated steam to the engine leading line, which adjusts the throttle element in the bypass line as a function of the temperature of the reheated steam. 4. Steam generator according to claim 3, characterized in that in a known manner the temperature sensor is at the same time in operative connection with a cooler in front of the branch the bypass line is switched into the high pressure steam flow. 5. Steam generator according to claim 3, characterized in that the temperature sensor at the same time is in operative connection with a cooler, which is behind the branch of the bypass line is switched into the high pressure steam flow. 6. Steam generator according to claim 1, characterized in that a temperature sensor is connected in a manner known per se to the high-pressure steam line leading to the engine, which changes the amount of coolant of a cooler switched on behind the confluence of the bypass line in the high-pressure steam flow. 7. Steam generator according to claim 1, characterized in that in a known manner at least one flue gas-heated reheater heating surface is connected to the heat exchanger is. 8. Steam generator according to claim 7, characterized in that in a manner known per se the flue gas heated reheater heating surface in the flow direction of the partially expanded Steam is connected behind the heat exchanger. Considered publications:
Swiss patent specification No. 372 694. 1 sheet of drawings 709 650/141 9. 67 © Bundesdruckerei Berlin