JPS6131361B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust gas heat recovery device for a marine engine equipped with a dual pressure exhaust gas economizer and a large auxiliary boiler.

FIG. 1 shows a conventional example of a heat recovery device equipped with an exhaust gas economizer 1 having two types of high-pressure and low-pressure steam generation systems, and in which an auxiliary boiler drum also serves as a high-pressure steam-water separator 2B.

In such a heat recovery device, the water supply tank 3
An exhaust gas economizer system water supply flow path 5 is arranged from the exhaust gas economizer preheating section 1A to the low pressure steam water separator 1A and the high pressure steam water separator (auxiliary boiler drum) 2B. The supplied water is heated by the preheating section 1A and sent to the separators 2A and 2B. A part of the heated water supply is returned to the water supply pump 3 to increase the temperature of the water supply. Each steam/water separator 2A, 2B
are provided with circulation passages 7A and 7B, and the boiler water in each steam-water separator 2A and 2B is circulated through circulation pumps 6A and 6.
B to the low-pressure evaporator 1B and high-pressure evaporator 1C, heated by exhaust gas, and returned to the steam-water separators 2A and 2B.

The steam separated in the low-pressure steam-water separator 2A is sent as miscellaneous steam to equipment 8 that uses miscellaneous steam, and the steam in the high-pressure steam-water separator 2B is sent to the superheating section 1D, where it is further heated to a high temperature. Rear steam turbine 9
The water is sent to the water supply tank 3, and after being condensed in the condenser 10, it is returned to the water supply tank 3.

In a device with such a configuration, the operating pressure of the low-pressure steam generation system and the high-pressure steam generation system is determined by the balance between the amount of steam used and the amount of heat recovered, and the high-pressure steam generation system is set at a high pressure that can secure the operating pressure of the steam turbine 9. The low-pressure steam generation system is planned to operate at as low a pressure as possible to increase the amount of heat recovered from the exhaust gas.

Here, the amount of heat in the exhaust gas decreases due to a decrease in atmospheric temperature or due to operation with reduced engine output.
When a large amount of steam is required to heat cargo oil in a tanker, etc., it is impossible to generate the necessary steam with the exhaust gas economizer alone, so an auxiliary boiler is operated to compensate for the lack of steam and the exhaust gas economizer is used. Perform parallel operation with In FIG. 1, a boiler system water supply flow path 11 is provided from the water supply tank 3 to the high pressure steam water separator 2B, and the water supply is sent to the steam water separator 2B by a boiler water supply pump 12. 13 is equipment that requires boiler-generated steam for heating cargo oil tanks and the like.

When the auxiliary boiler is fired, the high-pressure steam generation system of the exhaust gas economizer is operated at the operating pressure of the auxiliary boiler. The operating pressure of the large auxiliary boiler normally installed on tankers is considerably higher than the operating pressure of the high-pressure steam generation system when the exhaust gas economizer is operated alone, so when the auxiliary boiler and the exhaust gas economizer are operated in parallel, the exhaust gas The operating pressure of the economizer's high-pressure steam generation system increases, and the temperature difference between the exhaust gas and steam becomes smaller.
The amount of heat recovered from the exhaust gas will be significantly reduced.

This invention has been proposed to solve the problems of the prior art, and its purpose is to provide an exhaust gas heat recovery device that can recover more heat than the conventional one.

The exhaust gas heat recovery device according to the present invention includes an exhaust gas economizer having two types of steam generation systems, high pressure and low pressure, and connects the high pressure steam separator of the high pressure steam generation system to the auxiliary boiler operated at a higher pressure than the exhaust gas economizer. Exhaust gas economizer system water supply passage that also serves as a steam drum and sends water to the high-pressure and low-pressure steam separators in the high-pressure and low-pressure steam generation system, and the boiler system water supply that sends boiler feed water to the high-pressure steam and water separators during auxiliary boiler operation. A switching device is provided for merging the boiler system water supply flow path with the exhaust gas economizer system water supply flow path before the high-pressure steam separator and switching the flow path at this merging point. The supply flow path to the low-pressure evaporation section and the water supply flow path are connected by an auxiliary flow path and a switching device, and the supply flow path to the high-pressure evaporation section of the circulation flow path and the low-pressure steam separator are connected by the auxiliary flow path. and a switching device, and a return channel from the high-pressure evaporation section of the circulation channel and the low-pressure steam separator are connected by an auxiliary channel and a switching device, and the overheating of the high-pressure steam separator is connected to The supply flow path to the section and the supply flow path to the equipment of the low pressure steam water separator are connected by an auxiliary flow path and a switching device, and when the auxiliary boiler is operated, the auxiliary boiler and the exhaust gas economizer are disconnected by the switching device. The exhaust gas economizer is operated at a lower pressure than the auxiliary boiler.

The present invention will be described below based on an illustrated embodiment. It should be noted that the same or equivalent parts as in the prior art are denoted by the same reference numerals and the explanation thereof will be omitted. Second
As shown in FIG. 3, the boiler system water supply channel 11 is joined to the exhaust gas economizer system water supply channel 5 in front of the high pressure steam/water separator 2B, and a switching device 14 for switching the channel is provided at this junction. Circulation channel 7
The supply channel A to the low-pressure evaporator 1B and the water supply channel 5 are connected by an auxiliary channel 15 and a switching device 16. The supply flow path of the circulation flow path 7B to the high-pressure evaporator 1C and the low-pressure steam separator 2A are connected by an auxiliary flow path 17 and a switching device 18. Return flow path from the high pressure evaporator 1C of the circulation flow path 7B and the low pressure steam separator 2A
are connected by an auxiliary flow path 19 and a switching device 20. The supply flow path to the superheating section 1D of the high pressure steam water separator 2B and the supply flow path to the equipment 8 of the low pressure steam water separator 2A are connected by an auxiliary flow path 21 and a switching device 22. Furthermore, a supply flow path 24 having a pressure reducing valve 23 is provided from the high pressure steam/water separator 2B to the superheating section 1D.

In such a configuration, when the exhaust gas economizer 1 is operated independently, the flow path shown by the thick line in FIG. 2 is formed, and the same operation as in the prior art is performed.

When the auxiliary boiler is operated, the newly installed flow path and switching device are used to operate as shown in FIG. 3. That is, the water pumped from the water tank 3 by the water pump 4 is supplied to the preheating section 1A,
It is heated in the low pressure evaporator 1B and sent to the low pressure steam separator 2A. Boiler water in the low-pressure steam-water separator 2A is sent to the high-pressure evaporator 1C by the circulation pump 6B, heated by exhaust gas, and returned to the low-pressure steam-water separator 2A as a steam-water mixture. Part of the steam separated from steam and water here is equipment 8 that uses miscellaneous steam.
Then, a portion passes through the superheating section 1D, is further heated, and is sent to the turbine 9.

The auxiliary boiler (high pressure steam/water separator) 2B is supplied with water by a dedicated water supply pump 12 and operated independently.
The boiler-generated steam is sent to equipment 13 that requires boiler-generated steam, such as for heating cargo oil tanks. Further, if it is difficult to drive the turbine 9 with the exhaust gas economizer 1 alone, the insufficient amount of steam is supplemented by the supply flow path 24.

In this manner, when the auxiliary boiler is in operation, the exhaust gas economizer 1 is operated at low pressure independently from the auxiliary boiler as an economizer that generates single-pressure steam. Here, the operating pressure of the exhaust gas economizer 1 is 4 to 12 Kg/cm ² and the operating pressure of the auxiliary boiler is
Around 16Kg/ ^cm2 is appropriate.

With such a device, when the exhaust gas economizer is operated alone, it is no different from the conventional device (see Figure 4), but when the exhaust gas economizer and the auxiliary boiler are operated in parallel, in the conventional device a, the amount of recovered heat A ₀ is The amount of heat recovered was A ₁ , which was significantly reduced as the operating pressure increased, but in the case of the present invention (b), since the exhaust gas economizer is operated at a single low pressure during parallel operation, the amount of recovered heat is A ₂ , which is significantly lower than before. The amount of heat recovered will increase (see Figure 5).

In recent years, the amount of oil transported by tankers has increased with high viscosity, and many tankers operate while using auxiliary boilers to heat the oil tanks. That is, for more than half of the voyage, the exhaust gas economizer and the auxiliary boiler will be operated in parallel, and the benefit of the present invention in increasing the utilization of exhaust heat at this time is extremely large.

As described above, according to the present invention, when the auxiliary boiler and the exhaust gas economizer are operated in parallel, the auxiliary boiler and the exhaust gas economizer are separated, and the exhaust gas economizer is operated at a single pressure centered on the low-pressure steam separator, which is lower than the auxiliary boiler. Since the exhaust gas economizer is operated at a lower temperature, the amount of heat recovered by the exhaust gas economizer is greater than that of the conventional system, making it extremely economical.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a conventional exhaust gas heat recovery device, and FIG. 2 is a system diagram showing the exhaust gas economizer of the exhaust gas heat recovery device according to the present invention in independent operation.
Figure 3 is a system diagram showing parallel operation of similar equipment;
FIGS. 4 and 5 are diagrams comparing the heat recovery status of the conventional apparatus and the apparatus of the present invention. 1... Exhaust gas economizer, 1A... Preheating section,
1B...Low pressure evaporation section, 1C...High pressure evaporation section, 1D
...Superheating section, 2A...Low pressure steam separator, 2B...
High pressure steam/water separator (auxiliary boiler drum), 3...Water tank, 4...Water pump, 5...Exhaust gas economizer system water supply channel, 6A, 6B...Circulation pump, 7A, 7B...Circulation channel, 8...Equipment that uses miscellaneous steam, 9...Steam turbine, 10...Condenser, 11...Boiler system feed water passage, 12...Boiler feed water pump, 13...Requires boiler-generated steam Equipment, 14...Switching device, 15, 17, 1
9, 21...channel, 16, 18, 20, 22...
Switching device, 23... pressure reducing valve, 24... supply channel.

Claims (1)

[Claims] 1.Equipped with an exhaust gas economizer having two types of steam generation systems, high pressure and low pressure, the high pressure steam water separator of the high pressure steam generation system is also used as the steam drum of the auxiliary boiler that is operated at a higher pressure than the exhaust gas economizer, and the high pressure and low pressure Exhaust gas heat recovery system equipped with an exhaust gas economizer system water supply flow path that sends water supply to the high-pressure and low-pressure steam water separators in the steam generation system, and a boiler system water supply flow path that sends boiler feed water to the high-pressure steam water separator during auxiliary boiler operation. In the equipment, the boiler system water supply flow path is connected to the exhaust gas economizer system water flow path before the high pressure air water separator so that the exhaust gas economizer can be operated as a single pressure exhaust gas economizer independently from the auxiliary boiler when the auxiliary boiler is operated. A switching device is provided for merging and switching the flow paths at this merging point, and furthermore, the supply flow path to the low-pressure evaporation section of the circulation flow path and the water supply flow path are connected by an auxiliary flow path and a switching device, and the circulation The supply flow path to the high pressure evaporation section of the flow path and the low pressure steam water separator are connected by an auxiliary flow path and a switching device, and the return flow path from the high pressure evaporation section of the circulation flow path and the low pressure steam water separator are connected. The supply flow path to the superheating part of the high pressure steam water separator and the supply flow path to the equipment of the low pressure steam water separator are connected by the auxiliary flow path and the switching device. An exhaust gas heat recovery device comprising an exhaust gas economizer and an auxiliary boiler, characterized in that the exhaust gas economizer and the auxiliary boiler are connected by.