JPS5916641Y2 - Exhaust gas economizer water supply preheating device in diesel engine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an exhaust gas economizer feed water preheating device for a diesel engine.

Ships equipped with a diesel engine as the main propulsion engine are generally designed so that all the steam and electricity required during normal voyages are provided by effectively utilizing the main engine's exhaust gas energy. It is true.

For this purpose, an exhaust gas economizer is installed that uses the exhaust gas energy of the main engine as a heat source, which generates steam, supplies this steam to the necessary locations on the ship, and guides it to a steam turbine-driven power generator, that is, a turbo generator, to generate electricity and generate steam. A system is in place to supply electricity.

Conventionally, an exhaust gas economizer plant as shown in FIG. 1 has been provided for the above-mentioned steam generation.

That is, in FIG. 1, exhaust gas generated by a diesel engine 1 drives a supercharger 2 with a diesel engine, and its retained energy is transferred to boiler circulating water, which is the fluid in the pipe of an exhaust gas economizer 11 installed in an exhaust gas pipe 3. is released into the atmosphere.

On the other hand, the boiler circulating water given energy from the exhaust gas becomes a gas-liquid mixture, passes through the circulation path 10 communicating between the exhaust gas economizer and the steam-water separation drum 8, reaches the steam-water separation drum, and separates steam there.

The separated steam is then supplied to necessary locations inside the ship through the steam supply pipe 12.

Further, the boiler circulating water in the steam/water separation drum is replenished by water supply in the water supply tank 4.

That is, the water supply in the water supply tank is sucked by the water supply pump 5,
The water is pressurized and heated by the water supply combustor 7, and then supplied to the steam/water separation drum. Reference numeral 6 is a water supply pipe that communicates the water supply tank and the steam/water separation drum.

The heat source of the feedwater heater used in this system is either steam or high-temperature boiler circulating water, both of which are raised to high temperature and high pressure by an exhaust gas economizer.

On the other hand, as a recent trend in marine diesel engines, efforts are being made to improve the fuel consumption rate along with the increase in horsepower, and due to this improvement in the fuel consumption rate, the exhaust gas temperature at the outlet of the main engine's supercharger is becoming lower. Therefore, the heat transfer area of the exhaust gas economizer installed in the main engine exhaust gas system has to be increased.

As a result, the manufacturing cost of exhaust gas economizers increases and
In terms of performance, there is a decrease in performance due to increased difficulty in cleaning dirt on the outside of the heating tube, and furthermore, an increase in water level fluctuations in the steam/water separation drum due to changes in the specific volume of the circulating water in the exhaust gas economizer when the main engine load fluctuates. become.

In addition, in small and medium-sized main engines, due to insufficient exhaust gas volume and gas temperature, there are cases where the adoption of an exhaust gas economizer turbo plant has been postponed, or where parallel operation with an easel generator has no choice but to be implemented. .

In order to eliminate the above-mentioned drawbacks, the inventor succeeded in significantly improving the heat balance of the exhaust gas economizer plant by obtaining the heat source for heating the feed water supplied to the steam/water separation drum from a heat source other than the exhaust gas of the main engine. , which focuses on the possibility of reducing the heat transfer area of the exhaust gas economizer.

In other words, during normal voyages, the temperature of water supplied to the exhaust gas economizer is 20 to 40°C in the water tank (vacuum condenser 700mmH).
gVAC) is low, and if this is heated up using a heat source other than the heat source obtained by the exhaust gas economizer, the heat balance of the exhaust gas economizer plant can be greatly improved.

Incidentally, in the case of an 8.5kg/cm2G steam plant, if the feed water temperature is preheated from 30℃ to 65℃, the margin for the amount of steam generated by the exhaust gas economizer is approximately 6%.
In other words, the heat transfer area of the exhaust gas economizer can be reduced by 6%.

Note that in order to obtain a feed water temperature of 65°C, it is possible to find a suitable heating source within the diesel plant.

That is, the present invention is a cylinder jacket cooling system in which a cylinder jacket water cooling space and a fresh water cooler are connected through a cooling channel in order to utilize a part of the cooling loss heat of the cylinder jacket cooling system of a diesel engine as a 65°C heating source. A water preheater is provided upstream of the fresh water cooler to preheat the water supplied from the water tank to 65°C, and the preheated water is supplied to the exhaust gas economizer via the air/water separation drum.

An embodiment of the present invention will be described based on FIG.

20 is a cylinder jacket water cooling space, and 17 is a fresh water cooler, which are communicated by a cooling water passage 18, forming a cylinder jacket cooling system in which the cooling water is circulated by a pump (not shown).

Heat exchange is performed in the fresh water cooler 17 with the cooling seawater pipe 19.

The feed water preheater 16, which is interposed upstream of the fresh water cooler 17 of this cooling system, is especially installed in the middle of the feed water channel in order to preheat the feed water supplied from the water tank 4 to the brackish water separation drum 8 connected to the exhaust gas economizer 11. It is something that

Reference numeral 6 denotes a water supply waterway to the brackish water separation drum 8, the starting end of which communicates with the ice detection ink 4, and a water supply pump 5 and a water supply adjustment valve 14 are provided in the water supply waterway 6.

10 is a circulation path from the brackish water separation drum 8 to the exhaust gas economizer 11, and a circulation pump 9 is provided therein.

Two branched waterways 6a and 6b are formed between the water supply pump 5 and the water supply adjustment valve 14 of the water supply waterway 6, one of which has a valve 13 interposed therein, and the other 6b has a valve 15 for preheating the water supply. The heat is then transferred to the vessel 16, where heat exchange is to be carried out.

20 to 40°C flowing from the water tank 4 through the water supply channels 6 and 6b
The feed water is heated to the same temperature of 65° C. by the 65° C. jacket cooling water flowing through the feed water preheater 16 and reaches the brackish water separation drum 8.

Further, the jacket cooling water discharged from the feed water preheater 16 at 64° C. is cooled to 58° C. in the fresh water cooler 17 and reaches the cylinder jacket water cooling space 20 .

Note that the exhaust gas generated by the diesel engine 1 drives a supercharger 2 with a diesel engine, and then gives a part of its retained energy to an exhaust gas economizer 11 installed in an exhaust gas pipe 3, and then is released into the atmosphere.

As described above, according to the present invention described in the examples, it is possible to give a margin of 6% to the rated capacity of the exhaust gas economizer, that is, it is possible to secure more steam in the exhaust gas economizer, or it is possible to The area for expensive electric heating can be reduced, and in this case, since the feed water preheater exchanges heat between fresh water, troubles such as dirt and corrosion on the heat transfer surface can be reduced, and the fresh water cooler can be made smaller.

In addition, the waste heat of the easel main engine is effectively utilized.
Moreover, the amount of heat lost by cooling can be effectively utilized.

In addition, in a diesel engine, the same effect can be obtained even if the water supply is preheated by interposing a water supply channel to the brackish water separation drum of the exhaust gas economizer in the air cooler installed in the middle of the pipe from the supercharger to the scavenging chamber. effect can be obtained.

[Brief explanation of drawings]

Figure 1 is a system diagram of a conventional exhaust gas economizer plant.
FIG. 2 is a system diagram showing an embodiment of the present invention. 4... Water supply tank, 8... Brackish water separation drum, 11... Exhaust gas economizer, 16...
...Water preheater, 17... Fresh water cooler, 1
8... Cooling water channel, 20... Cylinder jacket water cooling space.

Claims (1)

[Scope of utility model registration request] A water preheater 16 is provided on the upstream side of the fresh water cooler 17 in a cylinder jacket cooling system in which the cylinder jacket water cooling space 20 and the fresh water cooler 17 are connected through a cooling channel 18.
An exhaust gas economizer feed water preheating device for a diesel engine, characterized in that the preheated water is preheated from the water tank 4, and the preheated water is supplied to the exhaust gas economizer 11 via the brackish water separation drum 8.