JPS6229604Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a marine reheat propulsion plant, and in particular includes a boiler equipped with a superheater, a reheater, and an internal slow-heater, a forward turbine, and a backward turbine. This invention relates to a marine reheat propulsion plant that is a mixed-pressure reverse turbine that is supplied with two types of steam: high-pressure steam and intermediate-pressure steam.

Generally, when applying a reheat plant cycle to a ship, the following problems can be cited as problems with conventional systems.

(1) When using a conventional reverse turbine, the steam consumption rate of the reverse turbine is poor, so the amount of steam required during reverse travel exceeds the amount of steam required during forward reheating.
Therefore, a large-capacity boiler must be installed for backward movement. This trend applies except in cases where boiler capacity is determined based on tank cleaning, that is, in the case of ships without tanker services, such as bulk carriers,
This is especially noticeable on LNG carriers.

(2) In the case of a conventional reheat cycle, when moving from a forward reheat state to a backward non-reheat state, there is a risk of burning out the reheat tube due to the steam to the reheater being cut off. In the case of an oil-fired boiler or a fluidized bed boiler with a reheater installed in the gas path,
It is necessary to bypass the heating gas of the reheater.

However, in order to bypass the heating gas,
It is necessary to provide a gas damper or the like for the high-temperature gas path, which complicates the structure and poses a problem of longevity, and sufficient maintenance is required in this regard. Furthermore, in the case of a fluidized bed boiler with a reheater installed in the bed, it is practically impossible to bypass the fluidized medium and there is a possibility of burning out the tube of the reheater.

There were other problems.

This idea was made in view of the above-mentioned conventional problems in marine reheat propulsion plants, and its purpose is to increase the boiler capacity compared to forward reheating by increasing the efficiency of the backward turbine. The objective is to make it possible to fit the reheat boiler within the capacity of a reheat boiler of an appropriate size, and to protect the reheat tube of the reheater from burning out when moving in reverse.

Next, the configuration of the present device will be explained in detail below based on the drawings. FIG. 1 shows one embodiment of the present invention, in which 1 is a superheater and 2a is a reheat boiler equipped with a reheater 3. 4 is a high-pressure turbine as a forward turbine, 5 is also an intermediate-pressure turbine, and 6 is also a low-pressure turbine. Reference numeral 21 denotes a mixed-pressure backward turbine, to which two types of steam, high-pressure steam and intermediate-pressure steam, are supplied, and is provided coaxially with the forward-use low-pressure turbine 6. The high pressure turbine 4 and the intermediate pressure turbine 5 are arranged on a common axis, as shown in the figure. 9
is the main condenser.

10 is a pipe that supplies steam to the high-pressure turbine 4 through the superheater 1, 11 is a passage that communicates the outlet of the high-pressure turbine 4 with the reheater 3, and 12 is the reheater 3.
This is a pipe line that communicates the inlet of the intermediate pressure turbine 5 with the inlet of the intermediate pressure turbine 5. 16, 17, 18, and 20 are all valves interposed in the middle of the pipe to control opening and closing of the flow path. An internal heat sink 22 is provided in the reheat boiler 2a. 23 is a pipe that branches off from the middle of the pipe 10 and communicates with the high pressure steam inlet of the mixed pressure backward turbine 21; This is a conduit that communicates with the inlet. Reference numeral 25 denotes a pipe line that branches from the middle of the pipe line 10 and communicates with the pipe line 11 in the middle through the internal heat absorber 22. Reference numeral 26 indicates a pipe line 25 that connects from the internal heat absorber 22 to the pipe line 11. This is a discharge conduit that branches out from the middle of the section. The conduit 25 is provided with valves 27 and 28 before and after the branch point of the conduit 26 for controlling opening and closing of the flow path.

FIG. 2 shows the flow of steam when a ship is propelled forward by the device of FIG. By opening the valves 16 and 17 and closing the valves 18, 20, 27, and 28, the steam from the superheater 1 can be transferred to
-6-9, and the forward operation of the ship is performed.

FIG. 3 shows the flow of steam when a ship is moved astern by this device. At this time, valve 16,
17 is closed and valves 18, 20, 27, and 28 are opened, a portion of the steam from the superheater 1 is guided to the high pressure steam inlet of the mixed pressure reverse turbine 21.
Part or all of the other parts are guided to the intermediate pressure steam inlet of the mixed pressure astern turbine 21 via the internal heat sink 22 and the reheater 3, and the ship is operated astern. In this case, the amount of steam guided to the pipe line 10 and the amount of steam guided to the pipe line 25
The distribution of the amount of steam led to the valve 18 and the valve 2
7, and the steam guided to the pipe 25 and flowing into the pipe 12, and the steam led to the pipe 25
The distribution of the amount of steam with the steam released by 6 is controlled by a valve 28.

According to the configuration of this embodiment, in the case of reverse movement, a part of the steam that has passed through the superheater is heated by the reheater 3 through the internal slow-heater 22 of the reheat boiler 2a, and then heated by the reheater 3. 21 to the intermediate pressure stage, the efficiency of the reverse turbine can be increased, and the capacity of the reheat boiler can be set to an appropriate size based on the forward reheating time. Also, the internal heat sink 22 is added to the reheater 3.
Since steam is passed through the tube, overheating and burning out of the reheat tube can be prevented. It also has the effect that the heat accumulated in the reheater during forward movement can be effectively utilized by the reverse turbine, and this effect is particularly noticeable in the case of fluidized bed boilers.

[Brief explanation of drawings]

Fig. 1 is a layout diagram of an embodiment of the proposed device, Fig. 2 is a system diagram showing the flow of steam when moving forward in the device shown in Fig. 1, and Fig. 3 is a system diagram showing the flow of steam when moving backward in the device shown in Fig. 1. FIG. 1...Superheater, 2a...Reheat boiler, 3...Reheater, 4...High pressure turbine, 5...Intermediate pressure turbine, 6...Low pressure turbine, 9...Main condenser, 1
0, 11, 12, 23, 24, 25, 26... pipe, 16, 17, 18, 20, 27, 28...
Valve, 21... Mixed pressure reverse turbine, 22... Internal heat sink.

Claims (1)

[Scope of utility model registration request] A mixed-pressure backward turbine comprising a boiler equipped with a superheater, a reheater, and an internal slow-heater, a forward turbine, and a backward turbine, and the backward turbine is supplied with two types of steam, high-pressure steam and intermediate-pressure steam. In a certain marine reheat propulsion plant, a part of the reverse steam that has passed through a superheater is guided to the high-pressure steam inlet of the reverse turbine, and part or all of the other part is passed through an internal slow-heater provided in the boiler and then regenerated. A marine reheat propulsion plant, comprising means for configuring a steam flow path that leads medium-pressure steam to the inlet of the reverse turbine via a heater.