JP2775851B2 - Thermal power plant system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to a thermal power plant system having LNG vaporization equipment on the same premises, and more particularly, to a condenser for discharging the drainage (cold drainage) of an LNG vaporizer. The present invention relates to a thermal power plant system used as cooling water for a thermal power plant.

<Prior Art> FIG. 2 is a conceptual diagram of a configuration of a thermal power plant system having a conventional LNG vaporization facility on the same premises.

In the figure, 1 is a tank storing LNG, 2 is a vaporizer for vaporizing LNG supplied from the tank 1, 3 is a boiler, which burns NG (fuel gas) supplied from the vaporizer 2, The steam for turning the turbine 4 is produced. 41 is a condenser provided in the turbine 4 and 5 is a generator driven by the turbine 4.

The LNG vaporizer 2 takes in seawater for vaporization via a pipe 20 and returns cold water to the sea again. The condenser 41 also takes in the seawater for cooling the turbine exhaust through the pipe 8, and returns the heated wastewater whose temperature has risen to the sea again.

<Problems to be Solved by the Invention> In the power plant system having such a configuration, both the cold drainage and the hot drainage are pollution sources, and if the difference between the temperature of the intake water and the temperature of the wastewater is large, the effect on the environment is reduced. Since it cannot be ignored, there has been a problem that equipment for reducing the temperature difference is required.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a thermal power plant system that is as efficient as possible while minimizing the effect on the environment.

<Means for Solving the Problems> The present invention for solving the above-mentioned object comprises an LNG vaporizer (2) for gasifying liquefied natural gas using seawater as a heat source, and an LNG vaporizer.
A thermal power plant system comprising: a power boiler / turbine that generates steam by burning natural gas produced by a vaporizer and guides the steam to a condensing turbine (4) to generate power; Cooling water supply means (60) for supplying cold water after heat exchange discharged from the vaporizer as cooling water for a condenser (41) provided in the condenser turbine; A hot wastewater supply means (70) for supplying the hot wastewater after exchange as a heat source of the vaporizer, a cold wastewater reservoir (6) for storing cold wastewater, and a warm wastewater reservoir (7) for storing hot wastewater; A pipe (80) for mixing cold and hot drainage from the cold and hot drainage pools and discharging the mixed water to the sea, and the temperature of the mixed fluid flowing through the drainage pipe is adjusted to a predetermined temperature. A temperature controller that controls the mixing ratio of cold drainage from cold drainage and hot drainage from hot drainage 9) together comprises a, it is characterized in that the amount of fluid circulating between said cold waste water reservoir and the warm water discharge reservoir was balanced.

<Operation> The LNG vaporizer gasifies liquefied natural gas and discharges cold water after heat exchange. This cold waste water is supplied as cooling water for the steam turbine condenser by the cooling water supply means. The cooling water is discharged as hot water through a condenser, and the hot waste water is supplied to an LNG vaporizer via a hot water supply means. By balancing the amount of liquid circulating between the cold sump and the hot sump, the amount of liquid discharged into the sea can be minimized.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration block diagram showing one embodiment of the present invention. In the figure, 1 is an LNG tank storing LNG, 2 is LN
The G vaporizer 20 is a pipe for taking in seawater, and a backflow prevention valve 21 and a pump 22 are installed on the way. This LNG
The vaporizer 2 takes in the liquefied natural gas supplied from the LNG tank 1 and takes in the warm seawater through the pipe 20.
Liquefied natural gas is gasified by a vaporizer (eg, ORV) to produce a fuel gas.

Reference numeral 3 denotes a boiler, in which fuel gas produced by the LNG vaporizer 2 is supplied through a pipe 10, where it is burned to produce steam. Reference numeral 4 denotes a turbine. Hot steam generated by the boiler 3 is supplied through a pipe 30 to rotate, and the generator 5 is driven to obtain power from the generator 5.

Reference numeral 6 denotes a cold drainage tank, and the cold drainage after heat exchange in the LNG vaporizer 2 is supplied through a pipe 12 and stored therein. 41 is a condenser provided in the steam turbine. The steam after turning the turbine 4 is returned to water here,
It is sent to boiler 3 again via 31. Cooling water for the condenser is taken into the steam turbine condenser 41 from the cold sump 6 via a pipe 60. 61 is a pump arranged in the middle of the pipe 60.

Reference numeral 7 denotes a hot drainage pool in which hot water discharged from the steam turbine condenser 41 is stored via a pipe 42. 70 is a pipe, and the hot water stored in the hot drain reservoir 7 passes through the pipe 20,
It is for supplying to LNG vaporizer 2 and pump 71
And a backflow prevention valve 72 is installed.

Reference numeral 80 denotes a drain pipe having one end opening to the discharge port, 62 denotes a pipe connecting the cold drain 6 to the other end of the drain pipe 80, and 73 denotes a pipe connecting the hot drain 7 to the other end of the drain pipe 80. pipe
Flow control valves 63 and 74 are provided at 62 and 73, respectively.

The drain pipe 80 is provided with a pump 81 for mixing and discharging cold and hot waste water. Reference numeral 9 denotes a temperature controller, and reference numeral 91 denotes a temperature detector 91 for detecting the temperature of a mixed fluid of cold drainage and hot drainage discharged from the drain pipe 80 to the sea.

The temperature controller 9 receives the temperature signal et from the temperature detector 91 and the set temperature signal ts, and adjusts the opening degrees of the two flow control valves 63 and 74 so that the temperature of the mixed fluid becomes the set temperature. Control.

The overall operation of the system configured as described above will be described below.

The fuel gas produced by the LNG vaporizer 2 is sent to the boiler 3 where it is burned. The steam generated by the boiler 3 is sent to a turbine 4 to rotate the turbine 4 and rotate a generator 5 to obtain electric power.

Cold drainage discharged from the LNG vaporizer 2 is stored in a cold drainage reservoir 6. Then, the cold water stored here is supplied to the condenser 41 via the pipe 60. On the other hand, hot waste water discharged from the condenser 41 is stored in the hot waste water reservoir 7. And
The hot water stored here passes through pipes 70 and 20 to produce LNG.
It is supplied to the vaporizer 2.

In this way, the seawater taken in from the seawater inlet goes around the LNG vaporizer 2, the cold drainage 6, the condenser 41, and the hot drainage 7 in order of decreasing and increasing the temperature. When the level of the drainage stored in the cold drainage pool 6 and the hot drainage pool 7 is equal to or higher than a certain level (for example, L1 or L2 or higher in the drawing), the temperature controller 9 outputs the mixed fluid from the drain pipe 80. So that the temperature becomes the set temperature ts (this set temperature is set according to the set environmental standards)
The amount of fluid flowing through the pipes 62 and 73 is controlled, thereby changing the mixing ratio between the cold waste water and the hot waste water.

In this way, the discharge pipe 80 is controlled so that a fluid having a temperature determined within the range of the environmental standard is always discharged to the sea.

In the above embodiment, the amount of fluid discharged into the sea is very small if the amount of fluid circulating between the cold drain 6 and the hot drain 7 is balanced. Therefore, the control loop by the temperature controller 9 may be omitted.

<Effects of the Invention> As described in detail above, the present invention does not discharge cold wastewater from an LNG vaporizer or hot wastewater from a condenser directly to the sea, but also discharges it to the sea. Since the amount of the mixed fluid of the cold drainage and the hot drainage is small, the influence on the environment can be reduced. Further, since the hot waste water is supplied to the LNG vaporizer and reused there, the amount of seawater taken in can be reduced and the load on the pump 22 can be reduced.

Similarly, since the cooling water supplied to the condenser uses cold drainage having a lower temperature than seawater, the supply amount of the cooling water can be reduced and the load on the pump 61 can be reduced.
Therefore, an efficient thermal power plant as a whole can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
The figure is a conceptual diagram of the configuration of a thermal power plant system having a conventional LNG vaporization facility on the same site. 1 LNG tank 2 LNG vaporizer 3 Boiler 4 Turbine 5 Generator 41 Condenser 6 Cold drain 7, Hot drain 20,60 70 …… Pipe 80 …… Drain pipe, 9 …… Temperature controller

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F01K 9/00 F01K 17/02

Claims (1)

(57) [Claims] 1. An LNG vaporizer (2) for gasifying liquefied natural gas using seawater as a heat source, and burning natural gas produced by the LNG vaporizer to generate steam and condensing the steam. A thermal power plant system comprising: a power generation boiler / turbine that guides a turbine (4) to generate power; wherein a cooled wastewater after heat exchange discharged from the LNG vaporizer is provided to the condensing turbine. A cooling water supply means (60) for supplying water as cooling water for the water heater (41); and a hot wastewater supply means (70) for supplying the hot wastewater after heat exchange in the condenser as a heat source for the vaporizer. ), A cold drainage reservoir (6) for storing cold drainage, a hot drainage reservoir (7) for storing hot drainage, and a mixture of the cold drainage and the hot drainage from the cold drainage reservoir and the hot drainage reservoir to the sea. The temperature of the discharge pipe (80) and the mixed fluid flowing through the discharge pipe is adjusted to a predetermined temperature. A temperature controller (9) for controlling a mixing ratio of the cold drainage from the cold drainage and the hot drainage from the hot drainage, and a fluid controller circulating between the cold drainage and the hot drainage. Thermal power plant system characterized by balanced amounts.