DE19626372C1 - Method and device for improving the efficiency in steam power plants - Google Patents

Description

The invention relates to a method and a Vorrich to improve efficiency in steam power plants a steam turbine plant with partial turbines, the associated Nete partial capacitors in a main capacitor system summarized and on the cooling water side in a main cooling water current are connected in series.

DE 38 41 224 A1 discloses a variety of heat transfers options in the exhaust gas as well as in the exhaust steam path combi known gas turbine steam turbine power plants known also different purposes, but primarily the Er generation of heat, serve.

According to the prior art, the cooling water is one Steam power plant with the help of a cooling water pumps water source (cooling tower, receiving water, sea,...) and via the main cooling water pipe to the main cooling water system, that usually consists of a main capacitor and this parallel heat exchangers of the auxiliary cooling water systems exists.

The secondary cooling water system, takes as a closed Cooling circuit at a variety of cooling points (oil cooler the feed pump drive turbine, cooling devices  Suction, fresh air fans, mills,. . . ) via intercooler Heat from the auxiliary units to then by heat Transfer to a cooling water sub-stream of the main cooling water systems to couple into this cycle and remove ren.

The distribution of the leaving the cooling water pump Main cooling water flow between the main condenser and secondary cooling water system is usually done via the hy drastic design of the systems or possibly additional with the help of a booster pump. Often there is also a feed pump drive turbine, whose capacitor then also par to the main capacitor allel is switched.

In the part connected in series in the main capacitor condensers condensate the exhaust steam from each turbine because of a pressure that is particularly dependent on the particular Cooling water outlet temperature at the relevant partial condenser gate depends.

In the current direction through which the partial capacitors flow cooling water flow increase the cooling water outlet temperatures with each heat transfer in a subcon inevitably. That is the steam from the partial turbines available pressure drop, which by the resp is determined condenser pressure and immediately on the usable enthalpy affects the first flow through the partial condenser is largest and in reduce the subsequent partial capacitors.

Furthermore, the merger and Mi of the different tempered cooling water flows me the possible exergy potential behind the main capacitor al for the individual partial turbines be preserved right.  

The temperature differences at the mixing point are also due to the system, especially in summer with recooling cold water temperatures up to a cooling tower can rise to around 30 ° C. So with this high cold water temperatures no impermissibly high outlet temperatures structures in the secondary cooling water system, the heat of the secondary cooling water system for a clear less warm-up span than that of the main condensers sator plant. The water temperature at the cooling water outlet from the secondary cooling water system is always clear lower than the water temperature at the cooling water outlet from the main capacitor.

The object of the invention is therefore, even in swans kenden possibly relatively unfavorable environmental conditions for the main cooling water system, optimal exergy and effectiveness degree relationships on the series connected partial turbines to achieve and still possible with the cooling water to use transport capacity for heat dissipation.

The object is achieved in that individual or all, emerge from the partial capacitors the cooling water flows, before entering the following Sub-condenser additional cooling water is added.

This will cause heat transfer in the second flowed partial capacitor - and possibly another serial downstream partial capacitor - improved so that gün higher condensation conditions on the assigned Partial turbine come about.

It makes sense if the added cooling water almost completely from the main cooling water flow Entry into the first partial capacitor is branched off. This method is particularly advantageous when the from the main cooling water flow, before entering the first of the Partial condensers branched cooling water partial flows, wah  by bypassing one or more partial capacitors in the Bypass at least occasionally on a heat transfer are divided, as this causes the cooling water temperatures of the Ne streams are adjusted to the main cooling water flow, before returning to the main cooling water flow be added. The intended heat transfer takes place particularly advantageous in the heat exchangers of the Ne cooling water system takes place in this power plant area not to let any performance limiting factors arise.

The invention thus takes account of the knowledge that when mixing two different tem perforated cooling water flows, the admixture to egg if possible ner place should take place at which the temperatures of the Cooling water flows do not deviate too much from one another.

Starting from a system according to Fig. 2/3, which corresponds to the state of the art, the invention is explained on a system according to Fig. 1/3.

Using the example of this system consisting of two partial condensers, the procedure according to the invention is such that the main cooling water stream ( 2 ) leaving the cooling water pump ( 1 ) is divided before entering the first partial condenser ( 3 a), so that only part of the main cooling water stream ( 2 ) enters the first partial condenser ( 3 a), while at least part of the remaining partial flow - possibly via a pressure booster pump ( 5 ) - bypasses the most partial condenser ( 3 a), flows through the secondary cooling water system ( 4 ) and as Cooling water partial flow ( 7 ) leaves the system to be mixed directly behind the most partial condenser ( 3 a) with the cooling water partial flow ( 9 ) exiting there. This then - possibly with a further cooling water admixture ( 10 and / or 11 ) - which depends on the cooling water temperature ( 7 ) - enters the serial condenser ( 3 b).

This inventive admixture of two th capacitor (3 b) on the one hand, the cooling water throughput (8) by the second partial condenser (3 b) increases and hence its cooling water outlet temperature lowers abge. On the other hand, due to the previous heat transfer in the first partial condenser ( 3 a), the temperature increase in the main cooling water flow ( 9 ) has risen to a level comparable to that of the cooling water flow ( 7 ).

The reduced cooling water outlet temperature at the partial condenser ( 3 b) increases the usable pressure drop due to the reduced condenser pressure in the partial turbine ( 3 b) assigned to the partial turbine and the efficiency of this partial turbine can be improved and thus the overall efficiency of the system can be increased accordingly weighted. On the other hand, the cooling water partial flows already heated in the secondary cooling water system are still used for effective heat transfer in the partial condensers behind the first partial condenser.

From Fig. 3/3 it can be seen how in a system in which neither an external cooling water additive ( 11 ) nor a bypass ( 10 ) is provided, the cooling water partial flow ( 7 ) through the secondary cooling water system ( 4 ) to the partial condensers ( 3 b) and ( 3 c) is performed.

Further possibilities by bypassing, branching or, if necessary, early decoupling from the secondary cooling water system ( 4 ) to improve the conditions depend on the still economical construction effort for the devices. However, the basic variants are already shown concretely in Fig. 1/3.

In principle, however, every line arrangement is the serves to solve the task, as a special off to see how the method according to the invention is implemented, and this regardless of the number of formworks in a row Partial condensers, the type of cooling water supply and the size of the respective cooling water partial flows.

Thus, the special design according to Fig. 3/3 makes it clear that the bypassing of the first partial capacitor ( 3 a) can already suffice to improve the condensation conditions in the subsequent partial capacitors ( 3 b) and possibly ( 3 c) to equalize the temperatures of the partial flows to be mixed and thus also to secure and use possible heat transfer and heat transport capacity for the necessary heat dissipation.

However, such measures are also supported by the volu metric ratio of the cooling water partial flows to each other and the success in the individual heat transfer systems determining temperature increases.

Reference list

1 cooling water pump
2 Main cooling water pipe - outlet pipe of the cooling water pump
3 capacitor system 3 a, 3 b, 3 c, partial capacitors of the main capacitor system
4 secondary cooling water system
5 booster pump
6 Capacitor of the feed pump drive turbine
7 Auxiliary cooling water system outlet line
8 Outlet line of the main condenser system
9 outlet line at the first partial condenser 3 a
10 Cooling water partial flow branched off possibly behind the booster pump
11 If necessary, externally supplied cooling water flow

Claims (8)

1. Process for efficiency improvement in steam power plants with a steam turbine system with partial turbines, the associated partial condensers are combined in a main condenser system and are connected in series in a main cooler on the cooling water side, characterized in that individual or all of the partial condensers emerging from cooling water flows before entering additional cooling water is added to the downstream partial condenser. 2. The method according to claim 1, characterized in that the mixed cooling water almost completely from the Main cooling water flow before entering the main condensate is branched off. 3. The method according to claim 1 or 2, characterized in that that of the main cooling water flow, before entering the he Most of the partial condensers branched cooling water partial streams while bypassing one or more Partial capacitors in the bypass at least occasionally heat transfer are involved. 4. The method according to claim 3 characterized in that heat transfer at least partially in the heat a secondary cooling water system.   5. Apparatus for performing the method according to one of claims 1 to 4, characterized in that on individual, or all of the partial condensers ( 3 a) and / or ( 3 b) leaving cooling water lines, before entering the subsequent partial capacitors wide re, cooling water supply lines are connected. 6. The device according to claim 5, characterized in that the connected, cooling water supply lines all or in part to the cooling water pump leaving sending main cooling water line ( 2 ) are branched off before entering the main condenser system ( 3 ). 7. Device according to one of claims 5 to 6, characterized in that the branches on the main cooling water line ( 2 ) before entering the main condenser system ( 3 ), cooling water supply lines ( 7 ) and ( 10 ) during the order of one or more Partial condensers in the by pass are at least occasionally routed through one or more heat transfer systems ( 4 ). 8. The device according to claim 7, characterized in that a heat transfer system ( 4 ) consists of a secondary cooling water system.