JPS62162803A - Exhaust gas economizer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an exhaust gas economizer that recovers heat from high-temperature exhaust gas discharged from a main engine such as a diesel engine.

[Conventional technology]

FIG. 2 shows a conventional exhaust gas economizer.

Condensate collected as drain from the low pressure steam service system 16 and the high pressure steam service system 17 is collected in the drain tank 1 and supplied to the condenser 2.

On the other hand, the exhaust gas from the 1 generator turbine 3 is sent to the condenser 2.
It exchanges heat with the cooling water, is cooled, becomes condensate, is sucked by the condensate pump 4, and is supplied to the water supply pump 5.

On the other hand, the water supply pump 5 sucks the drain from the low pressure brackish water separator (or low pressure flasher) 11.

Furthermore, a portion of the boiler water sucked from the high-pressure brackish water separator (or high-pressure flanyard) 9 by the boiler circulation water pump 12 is supplied to the feed water pump 5 via the temperature control valve 14 .

The temperature control valve 14 is connected to the discharge side of the water supply pump 5 (or a part of the gas economizer 6).
The temperature of the water supply at the inlet fli+ is detected, and the opening degree is controlled to maintain the same temperature change at a specified value. That is, temperature adjustment valve 1
The amount of boiler water passing through 4 is controlled.

OF gas economizer - preheater 7 arranged in main body 6
The feed water, which has become high in temperature by absorbing the energy of the exhaust gas, passes through the high-pressure brackish water separator water supply control valve 8, the high-pressure brackish water separator 9, the low-pressure brackish water separator water supply control valve 10, and then the low-pressure brackish water separator 11. is supplied with water.

The boiler water stored in the high-pressure brackish water separator 9 is used by the boiler water circulation pump 12 to absorb exhaust gas energy by the high-pressure steam generator 13 in the exhaust gas economizer body 6.
The brackish water mixture is collected in a high-pressure brackish water separator 9 and separated into brackish water.

A part of the steam separated in the high-pressure brackish water separator 9 absorbs exhaust gas energy by the superheater 15 in the exhaust gas economizer body 6 and becomes superheated steam, which is supplied to the generator turbine 3.

On the other hand, a part of the steam taken out from the high pressure steam separator 9 is supplied to the high pressure steam service system 17.

Further, a part of the steam taken out from the low-pressure steam separator 11 is supplied to the generator turbine 8, and a part is supplied to the low-pressure steam service system 16.

[Problem that the invention seeks to solve]

In order to prevent the occurrence of stress corrosion cracking in the steam generator of the exhaust gas economizer, the amount of water supplied to the high-pressure steam generator 13 needs to be 5 to 8 times the amount of steam normally generated. (
That is, it is necessary to set the circulation ratio to 5 to 8. ) In the conventional system, in order to maintain the water supply temperature to the preheater 7 at a specified temperature, high-temperature boiler water is returned to the low-temperature condensate system from the discharge side of the boiler water circulation pump 12, but one generator turbine Because the feed water temperature changes due to disturbance factors such as load fluctuations in 3 and changes in the temperature of the cooling water in condenser 2,
The opening degree of the temperature/cold adjustment valve 14 is not constant and varies.

That is, a high pressure steam generator 1 using a boiler water circulation pump 12
Since a stable supply of circulating water to 3 cannot be ensured and the circulation ratio cannot be maintained correctly, stress corrosion cracking of the high pressure steam generator 13 due to insufficient water supply to the high pressure steam generator 18 in the exhaust gas economizer body 6. This will encourage the occurrence of accidents.

[Failure to solve the problem]

In order to maintain the feed water temperature at a predetermined value without reducing the co-feeding of boiler water to the high-pressure steam generator, a portion of the condensate water is placed in a heat transfer tube installed in a high-pressure brackish water separator. To provide an exhaust gas economizer equipped with a system for flowing water, generating high-temperature water, and returning it to a water supply system.

[Effect]

For example, if the temperature of the feed water entering B is low, part of the condensate is converted into high-pressure brackish moisture): A part of the condensate is put into a heat transfer tube in the vessel, where the temperature of the condensate is raised to make high-temperature water, and the high-temperature water is supplied as water. Mix it back into the system and raise the temperature of the feed water.

〔Example〕

The present invention will be explained based on the embodiment shown in FIG.

Inside the exhaust gas economizer body 6, in order from the upstream side in the flow direction of exhaust gas from the main engine, there are a superheater 15° and a high pressure evaporator 18.
．． A preheater 7 is also arranged. The preheater 7 communicates with the high-pressure brackish water separator through a pipe having a water supply control valve 8 for the high-pressure brackish water separator in the middle, and branches from a pipe on the upstream side of the control valve 8, and has a water supply control valve 10 for the low-pressure brackish water separator in the middle. It communicates with a low-pressure brackish water separator 11 by a pipe equipped with.

The steam section of the low-pressure steam water separator 11 communicates with the low-pressure steam service system 16 via a pipe, and the pipe that supplies drain after work in the low-pressure steam service system 16 to the drain tank 1 is connected to the low-pressure steam service system 16. has been done. Furthermore, the steam section of the low pressure brackish water separator 11 is connected to the generator turbine 3.
It also communicates with the middle of the. The boiler water pipe of the high-pressure brackish water separator 9 communicates with the inlet of the high-pressure evaporator 13 via a pipe equipped with a boiler water circulation pump 12 in the middle.
The outlet portion of No. 3 communicates with a high-pressure brackish water separator 9 through a return pipe. The steam section of the high pressure steam separator 9 communicates with the inlet of the superheater 15 and also with the high pressure steam service system 17. A high pressure steam service system 17 is also in communication with the drain tank 1.

The outlet of the superheater 15 communicates with the inlet of the generator turbine 8 1
The outlet of the generator turbine 3 communicates with the condenser 2 via a pipe. The condenser 2 is further connected to a pipe through which the drain in the drain tank 1 is guided. The outlet of the water supply section 2 communicates with the inlet of the water supply pump 5 through a water supply pipe equipped with a condensate pump in the middle. A pipe is connected to the outlet of the condensate part of the low-pressure brackish water separator 11, and this condensate pipe 19 is connected to a water supply pipe upstream of the inlet of the water supply pump 5. or.

The condensate pipe 19 branches in the middle and communicates with the inlet of a heating coil 18 disposed in the high-pressure brackish water separator 9, and the outlet of the heating coil 18 is once connected to the condensate pipe 19 via a regulating valve 14. ing.

The outlet ml+ of the water supply pump 5 communicates with the inlet of the preheater 7 via a water supply pipe.

The boiler water sucked from the high-pressure brackish water separator 9 by the boiler water circulation pump 12 is transferred to the exhaust gas economizer body 6.
Thermal energy in the exhaust gas is absorbed by the high-pressure steam generator 13 in the exhaust gas to form a brackish water mixture, which is returned to the high-pressure brackish water separator 9.

On the other hand, the inlet temperature of the feed water of the relay unit 7 in the exhaust gas economizer main body 6 (or the outlet temperature of the water supply bonder 5) is determined by directing a portion of the condensate from the low pressure brackish water separator 11 into the high pressure brackish water separator 9. The high temperature water obtained by passing through the heating coil 18, which is a heat transfer tube, is passed through the temperature adjustment valve 1.
4 and the rest of the condensate (the portion that does not pass through the heating coil 18). The temperature control valve 14 detects the temperature of the inlet of the preheater 7 (or the discharge side of the water supply pump 5), and the water flows through the heating coil 18 provided in the high-pressure brackish water separator 9 so that this temperature becomes a specified value. It has the function of controlling the amount of condensate.

〔Effect of the invention〕

Since the temperature of the feed water can be controlled without extracting and mixing a portion of the boiler water sent to the steam generator, it is possible to supply a stable amount of boiler water to the high pressure steam generator, reducing stress in the high pressure steam generator. It can solve various problems caused by insufficient amount of circulating water to the steam generator, such as corrosion cracking.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, and FIG. 2 is a system diagram of a conventional device. 5... Water supply pump, 6... Exhaust gas economizer, 7... Preheater, 9... High pressure brackish water separator, 13...
...High pressure steam generator, 15... Superheater, 18... Heating coil Ko 1 diagram

Claims (1)

[Claims] A superheater, a high-pressure steam generator, and a preheater are arranged in the exhaust gas economizer body in order from the upstream side in the main engine exhaust gas flow direction, the outlet of the preheater communicates with the high-pressure brackish water separator, and condensate flows to the upstream side of the water supply pump. water supply pipes are connected, the water supply pump outlet communicates with the preheater inlet via the water supply pipe, the high-temperature water section of the high-pressure brackish water separator and the high-pressure steam generator are connected through a circulation system, and the high-pressure brackish water In an exhaust gas economizer that communicates the steam section of the separator with the inlet of the superheater, a heat transfer tube is disposed in the high-pressure brackish water separator, and a portion of the condensate is guided to the heat transfer tube upstream of the feed water pump. An exhaust gas economizer characterized by having a system for supplying water to the side water supply pipe.