SU1740702A1 - Method for power increase of condensation turbine plant - Google Patents

Abstract

The invention relates to a power system and can be used in condensation turbines of thermal and nuclear power plants to increase their efficiency by reducing exhaust energy losses. When the value of the ratio of the value of the exhaust energy losses of the previous two-cylinder low-pressure cylinder (LPD) to the amount of exhaust energy losses of the latter along the cooling water of the two-line LPD equal to 1.24, the regenerative heater along the condensate of the latter along the condensate to the course of cooling water of the low-pressure cylinder The subsequent regeneration heater along the condensate is disconnected from the steam extraction of the latter along the course of the cooling water of the low-pressure cylinder when the specified value is exceeded The ratio of exhaust energy loss 1 or y

Description

This invention relates to a power system and can be used in condensing steam turbine installations of thermal power plants and nuclear power plants.

There is a known method for increasing the power of a condensing turbo unit by disconnecting regenerative heaters from steam extraction, supplying steam for disconnected heaters to at least two low-pressure two-flow cylinders and draining exhaust steam from each stream to condensers, followed by condensation during successive supply of cooling water to condensers.

The disadvantages of this method are reduced cost-effectiveness due to the incomplete realization of the vacuum in a cold condenser. Since steam costs for low pressure heaters are about

the same, then the mass flow rate of steam through all the exhausts is almost the same. But in the exhausts connected to the first condenser along the cooling water, the volume flow rate of steam can be 1.2–1.5 times higher than in the subsequent ones. The water vacuum in the indicated condenser cannot be fully realized due to the increase in the exhaust energy loss of the last stage and even the possible exhaustion of the expansion capacity of the oblique cut of the stage.

The purpose of the invention is to increase the efficiency of a turbine installation by reducing the exhaust energy losses.

The drawing shows the Turbo-installation scheme, on which the method is implemented.

VI

S

with

N:

A condensing turbine unit contains at least one or several low pressure cylinders (LPCs) 1 and 2. Exhausts 3, 4 and 5. Used by pipes 8, 9 to condensers 9, 10, which are connected by pipeline 11 in series through cooling water.

Condensate from condensers 9, 10 (main condensate) is supplied by pump 12 via pipeline 13 to low-pressure regenerative heaters (HDPE) 14, 15 In this case, HDPE 14 is connected to the extraction 16 of low-pressure cylinder 1, 2 through pipeline 17, which connects pipelines 18 and 19, and the PND 15 - a pipeline 20 to the selection 21 of the low-pressure cylinder 1, 2. The pipeline 20 is connected to the pipeline 22, 23. The pipelines 19 and 23 connected to the selections 16, 21 from the latter along the cooling water of the low-pressure cylinder 2, are equipped with valves 24, 25 respectively.

In the version of the turbo with one LPC, i.e. with two exhausts 3, 4, each of the exhaust 3.4 is connected to its own condenser, for example 9, 10. With one condenser, each of the exhaust 3, 4 is connected to a separate section of the condenser (not shown).

The method is carried out as follows.

Steam from the exhaust 3-6 LPCs 1, 2 are directed through pipelines 7, 8 to condensers 9, 10, where it is cooled by water supplied through pipe 11 and condenses. The resulting condensate (main condensate) is directed by a condensate pump 12 through line 13 to the PND 14 and 15, which are connected in series through the main condensate. In PND 14, 15, the main condensate is heated with steam taken from selections 16, 21, respectively. When feeding regenerative HDPE 14, 15 with steam from selections 16, 21, LPCs 1 and 2 determine and compare among themselves the values of exhaust loss from exhausts 3, 4 and 5, 6 LPCs 1 and 2. These values are determined by a detailed calculation of the turbo-installation throughout the operating range of loads and cooling water temperatures using well-known programs that take into account the non-uniformity of steam parameters at the exhaust. If the value of exhaust loss from exhaust 5, 6 of the latter in the course of cooling water of LPC 2 is at least 1.24 times less than the value of exhaust loss from exhaust 3, 4 of the previous one along the course of cooling water of LPC 1, disconnect the PND 14 from selection 16 of LPC 2 by close the valves 24 on the pipeline 19. In this case, the flow

the pair in the selection 16 and the low-pressure cylinder 1 is doubled, the steam consumption from the low-pressure cylinder 1 to the capacitor 9 decreases, and from the low-pressure cylinder 2 to the condenser 10 it increases by an amount equal to half of the flow rate on the PND 14. This redistribution of flow through the exhaust 3,4 and 5, 6 with the claimed ratio of exhaust losses provides a total reduction in power loss with output speed.

If the ratio of exhaust losses after disconnecting the PND 14 of the LPC 2 remains greater than 1.24, then disconnect the PND 15 from the selection 21 of the CND 2 by closing the valve 25 on the pipeline 23

further redistribution of the values of exhaust losses between exhausts 3, 4 and 5 b. So, when implementing the method on the turbine K-1070-60 / 1500-3 in accordance with the prototype, the steam consumption in each capacitor

It is 1744.4 t / h, while the exhaust loss in the first condenser along the cooling water is 11.68 kcal / kg, in the second - 6.95 kcal / kg. The ratio of the values of the exhaust loss is

11.62 / 6.95 1.67. In accordance with the proposed method, when the ISfe 3 PND is disconnected from selections from the low-pressure cylinder, the exhaust of which is directed to the condenser, which is the last to be cooled during the course of water cooling, the steam consumption to the condensers is redistributed. In the first condenser, the steam consumption is 1638.8 t / h, in the second - 1849 t / h, the exhaust loss is 11.06 kcal / kg and 7.61 kcal / kg, respectively. It is easy to determine the loss

power output speed (hB) when working on the prototype method and the proposed method.

In the first case

AM, 1744.4 (11.68 + 6.95) ,,, QO D

D NB p OSI - 37789 kW,

Ltd

in the second - 1638.8-11.06 + 1849.4 7.61

0.86

 37440 kzt.

Thus, in the inventive method, the exhaust power loss is reduced at an output rate, resulting in an increase in the efficiency and power of the turbine.

Claims (1)

Formula invented and A method for increasing the capacity of a condensing turbo unit by disconnecting regenerative heaters from steam extraction, steam supply of disconnected heaters to at least two low-pressure two-cylinder cylinders and removal of exhaust steam from each stream to condensers, followed by condensation during the successive supply of cooling water to condensers, characterized in that - reduce the exhaust energy loss, determine the ratio of the value of the exhaust energy loss of the previous cylinder of the low pressure cylinder along the cooling water to the value of the latter’s energy losses during the cooling water flow of the low pressure cylinder and when the ratio reaches 1.24 turns off the regenerative preheater first in the course of condensate from the steam extraction of the latter during the cooling water flow of the low pressure cylinder, and when exceeding the specified value of the ratio of the values of exhaust energy losses, turn off the following along the course of the condensate, the regenerative preheater from the steam extraction of the latter along the course of the cooling water of the low pressure cylinder.