JP5873464B2 - Drain collection device - Google Patents

Description

  The present invention relates to a drain recovery device that is installed in a steam plant having a steam generation device and a steam consumption device, collects drain generated by the steam consumption device, and supplies water to the steam generation device.

  Steam ships, that is, ships with a propulsion engine such as a steam turbine are already exceptional, but steam is still used as a heat source or power source for marine equipment, so steam plants are still an important component of ships. It is. For example, a general merchant ship supplies steam generated by a boiler or an exhaust gas economizer to a heat exchanger disposed in a fuel oil tank to heat the fuel oil in the fuel oil tank. That is, a steam plant for heating the fuel oil with steam is provided. This is because heavy oil frequently used as marine fuel oil has poor fluidity at room temperature and cannot be transported by a pump as it is.

  In such a steam plant, the steam supplied to the heat exchanger changes into liquid (water), that is, drains and is discharged. In addition, in order to distinguish from the liquid (water) generated by dew condensation or the like, the liquid (water) discharged from the heat exchanger may be referred to as “vapor drain”, but in this specification, simply “drain”. Call it.

  After the drain is collected, it is supplied to the boiler and reused as can water. If the drain cannot be effectively recovered and reused, a large amount of preliminary canned water is required. However, an increase in the amount of reserved canned water is not preferable because it leads to a reduction in the effective weight of the cargo (so-called payload). Therefore, in a marine steam plant, drain recovery and reuse are particularly emphasized, and a drain recovery apparatus for that purpose has been proposed.

  For example, FIG. 3 of Patent Document 1 discloses a drain recovery device that cools drain with seawater and returns it to a water supply tank. Since this drain recovery device (hereinafter referred to as “first conventional technology”) returns the entire amount of drain to the water supply tank, there is no loss of drain. Therefore, consumption of canned water can be effectively suppressed and the amount of reserve canned water mounted can be reduced.

  However, the drain recovery apparatus according to the first prior art has a problem that heat efficiency is poor and fuel consumption is large. The drain discharged from the heat exchanger is still hot water of high temperature and high pressure and contains a considerable amount of available energy, but much of this energy is thrown away into the cooling water (seawater). is there.

  Further, Patent Document 1 discloses a drain recovery device that returns the water to the water supply tank without cooling the drain (FIG. 2 of Patent Document 1). Since this drain recovery device (hereinafter referred to as “second prior art”) does not cool the drain, the energy loss is small. However, since the high-temperature and high-pressure drain that has flowed into the water supply tank is depressurized, a part of the drain evaporates to become steam (flash steam) and is emitted into the atmosphere. As a result, there is a problem that loss of can water occurs.

  In FIG. 1 of Patent Document 1, the drain is cooled with boiler feed water (= the boiler feed water is heated with the drain) and returned to the feed water tank (hereinafter referred to as “third”). "Prior art" is disclosed. The third conventional technique aims to solve the problems of the first and second conventional techniques.

Japanese Patent Laid-Open No. 7-119918

  According to the third prior art, the intended purpose is achieved when the drain discharge amount and the boiler water supply amount are balanced. That is, can water and energy can be effectively recovered, and consumption of can water and fuel can be suppressed.

  However, drain discharge and boiler water supply are not always balanced. For example, the amount of drain discharge and the amount of water supplied to the boiler vary depending on the outside air temperature, seawater temperature, or the remaining amount of fuel oil in the tank. If the drain discharge and boiler water supply balance are lost, and the discharge increases temporarily or the water supply decreases temporarily, the drain will not be cooled sufficiently and flash steam will be generated. There is a problem that water is discharged out of the water supply tank, resulting in loss of canned water.

  This invention is made | formed in view of such a situation, and it aims at providing the drain collection | recovery apparatus which can collect | recover can water and energy effectively.

In order to solve the above problems, a drain recovery apparatus according to the present invention includes a water supply tank sealed against the atmosphere, a cooler that condenses and discharges steam, and a drain that is discharged from a steam consuming device. A drain introduction pipe that leads to the steam, a steam discharge pipe that discharges the flash steam generated from the drain from the water supply tank and leads it to the cooler, and water generated by the condensation of the flash steam in the cooler. e Bei condensate recovery pipe for guiding the water supply tank, the water supply tank, at a site higher than the liquid level of the pooled drain the water tank, a partition plate for partitioning the water supply tank into a first chamber and a second chamber The drain introduction line is connected to the water supply tank in the first chamber, the steam discharge line is connected to the water supply tank in the second chamber, and the first chamber and the It includes a communication pipe line communicating two chambers comprises a filter device for removing oil in the vapor in the middle of the communication pipe line.

  According to the above configuration, since all of the flash vapor is captured and condensed, the flash vapor does not diverge into the atmosphere. Therefore, consumption of canned water is suppressed. Moreover, since only flash steam is cooled, energy loss can be suppressed.

The partition plate may be a drooping wall that hangs down from a top plate of the water supply tank, and a lower end of the dripping wall may be configured to be submerged below a liquid level of a drain stored in the water supply tank .

The water supply tank includes first and second limit switches for detecting a liquid surface height, and both the first and second limit switches are arranged at a height between an upper end and a lower end of the hanging wall. In addition, the first limit switch may be disposed above the second limit switch and spaced from the second limit switch in the vertical direction .

Further, a buffer tank that is disposed in the middle of the condensate recovery pipe and temporarily stores water delivered from the cooler, and a transfer that transfers the water stored in the buffer tank to the water supply tank A pump, and the transfer pump is activated when the second limit switch no longer detects the liquid level, and then the liquid level in the water supply tank rises, and the first limit switch It may be stopped when it is detected .

It is a key map of a steam plant provided with a drain recovery device concerning the present invention. It is a conceptual diagram of a drain collection | recovery apparatus.

  Hereinafter, specific embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a conceptual diagram showing a state in which a drain recovery device 2 is incorporated in a steam plant 1. The steam plant 1 is a marine plant that heats the fuel oil in the fuel oil tank of the ship to increase the fluidity of the fuel oil, and includes an auxiliary boiler 3 that is disposed in an engine room (not shown), It is comprised with the heat exchanger 4 arrange | positioned in the fuel oil tank which does not. The heat exchanger 4 is a kind of steam consuming device, and the steam that has heated the fuel oil is condensed into liquid (water), that is, drained, and is discharged from the heat exchanger 4. The “auxiliary” of the auxiliary boiler 3 is a display used to distinguish it from the “main boiler” in the steamer, and is also used conventionally in a diesel ship (that is, a ship without a main boiler). It is a display. That is, there is a main boiler and the auxiliary boiler 3 does not support it.

  The drain collection device 2 includes a cascade tank 5 and a drain cooler 6. The cascade tank 5 is a tank sealed against the atmosphere, and is a water supply tank that temporarily stores drain collected from the heat exchanger 4 and supplies the auxiliary boiler 3 with water. The cascade tank 5 and the heat exchanger 4 are connected by a drain introduction pipe 7, and the drain discharged from the heat exchanger 4 flows into the cascade tank 5 through the drain introduction pipe 7. A steam trap 8 is inserted in the middle of the drain introduction pipe 7 to prevent steam from flowing into the cascade tank 5.

  A steam discharge pipe 9 is provided between the cascade tank 5 and the drain cooler 6 and communicates with each other. A pressure regulating valve 10 is inserted in the middle of the steam discharge pipe 9. The pressure regulating valve 10 is set to be opened when the internal pressure of the cascade tank 5 is equal to or higher than the atmospheric pressure and becomes higher than a predetermined pressure lower than the internal pressure of the heat exchanger 4.

  Thus, since the internal pressure of the cascade tank 5 is kept lower than the internal pressure of the heat exchanger 4, the drain that has flowed into the cascade tank 5 is decompressed and partly re-evaporates, so-called flash steam. Will occur. This flash steam flows through the steam discharge pipe 9 to the drain cooler 6.

  The drain cooler 6 is a cooler that cools and condenses flash steam flowing in from the cascade tank 5 with seawater. The drain cooler 6 is open to the atmosphere, and the internal pressure of the drain cooler 6 is kept lower than that of the cascade tank 5. The flash vapor is sucked into the drain cooler 6 by this pressure difference. Further, the condensate recovery pipe 11 communicates between the drain cooler 6 and the cascade tank 5, and the condensed water generated in the drain cooler 6 returns to the cascade tank 5 through the condensate recovery pipe 11.

  A buffer tank 12 is inserted in the middle of the condensate recovery pipe 11, and condensed water returning to the cascade tank 5 is temporarily stored. Further, the buffer tank 12 and a spare canned water tank (not shown) are communicated with each other through a supplementary water pipe 13, and an amount of spare canned water corresponding to the canned water lost due to steam leakage or the like is replenished from the spare canned water tank. The The buffer tank 12 is also open to the atmosphere. Further, a transfer pump 14 is inserted in the condensate recovery pipe 11 between the buffer tank 12 and the cascade tank 5, and the condensed water is pressurized and transferred to the cascade tank 5.

  Further, there is a water supply pipe 15 between the cascade tank 5 and the auxiliary boiler 3, and they communicate with each other. The drain stored in the cascade tank 5 is supplied to the auxiliary boiler 3 through the water supply pipe 15 and reused as can water. In the middle of the water supply pipe 15, a water supply pump 16 is arranged to pump the drain to the auxiliary boiler 3.

  By the way, the amount of steam generated in the auxiliary boiler 3 may exceed the amount of steam consumed in the heat exchanger 4. That is, excessive steam may be generated. In the steam plant 1, the surplus steam is recovered by the drain recovery device 2. That is, the auxiliary boiler 3 and the drain cooler 6 are connected by the surplus steam recovery pipe 17 so that the surplus steam flows to the drain cooler 6 through the surplus steam recovery pipe 17. The surplus steam that has flowed into the drain cooler 6 follows the same path as the flash steam, becomes condensed water, and returns to the cascade tank 5. Further, a pressure regulating valve 18 is inserted in the middle of the surplus steam recovery pipe 17, and when the steam pressure on the auxiliary boiler 3 side exceeds a predetermined pressure, that is, surplus steam is generated and the pressure is increased. Opened when rising.

  Next, the detailed structure of the drain collection | recovery apparatus 2 is demonstrated. As shown in FIG. 2, there is a partition plate 5a inside the cascade tank 5, and the inside of the cascade tank 5 is partitioned into a first chamber 5b and a second chamber 5c. The drain introduction pipe 7 is connected to the first chamber 5b, and the drain discharged from the heat exchanger 4 (not shown in FIG. 2) flows into the first chamber 5b. The steam discharge pipe 9 is connected to the top of the second chamber 5c, and the flash steam is discharged from the second chamber 5c.

  Further, a sight glass 5d is attached to the outer wall of the first chamber 5b so that the inside of the first chamber 5b can be observed from the outside, so that it flows into the first chamber 5b. If oil is mixed in the drain, it can be confirmed visually. In addition, a filter device 5e is attached to the top of the cascade tank 5, so that oil contained in the steam accumulated in the upper portion of the first chamber 5b is removed and allowed to flow into the second chamber 5c. Therefore, no oil is contained in the flash steam discharged from the second chamber 5c through the steam discharge pipe 9. A safety valve 5f is attached to the top of the first chamber 5b so that steam is discharged when the internal pressure of the cascade tank 5 exceeds a predetermined reference value.

  Further, limit switches 5g, 5h, and 5i are attached inside the cascade tank 5 to detect the liquid level inside the cascade tank 5. When the limit switch 5g detects the liquid level, the transfer pump 14 is stopped. After that, when the liquid level drops and the limit switch 5h no longer detects the liquid level, the transfer pump 14 is activated. Further, when the liquid level becomes lower than the limit switch 5i, a control device (not shown) of the steam plant 1 outputs an alarm to prevent emptying.

  The buffer tank 12 also includes limit switches 12a and 12b that detect the liquid level. When the buffer tank 12 becomes empty and the limit switch 12b no longer detects the liquid level, an alarm is output. Also, when the buffer tank 12 becomes full and the limit switch 12a detects the liquid level, an alarm is output.

  Since the drain recovery device 2 is configured as described above, the following operations and effects are produced. That is, since the cascade tank 5 is sealed with respect to the atmosphere, flash vapor generated from the drain does not diverge into the atmosphere. In other words, all of the flash steam generated from the drain is captured, cooled by the drain cooler 6, and returned to the cascade tank 5. Therefore, drain loss does not occur, and consumption of canned water can be effectively suppressed. Further, only the flash steam is cooled by the drain cooler 6 and the drain remaining in the cascade tank 5 is kept at a high temperature (saturation temperature), so that there is little energy loss. Therefore, the fuel consumption of the auxiliary boiler 3 can be suppressed. According to the inventors' estimation, it has been confirmed that the fuel consumption of the auxiliary boiler 3 can be reduced by about 8%.

  While specific embodiments of the present invention have been described above, the technical scope of the present invention is not limited by the above embodiments. The present invention can be freely applied, modified or improved within the scope of the technical idea shown in the claims.

  Moreover, although the auxiliary boiler 3 was shown as a specific example of a steam generator, the application object of this invention is not limited to a steam plant provided with the boiler of a narrow sense. For example, the present invention can be applied to a steam plant using an exhaust gas economizer or an exhaust gas boiler that generates steam using exhaust gas from an internal combustion engine or an industrial furnace as a steam generator.

  Moreover, in the said embodiment, although the example which applied this invention to the marine steam plant was shown, the application object of this invention is not restricted to a marine steam plant. It can also be applied to land-use steam plants. Further, it can be applied not only to industrial plants but also to civilian plants.

  Moreover, although the heat exchanger 4 was illustrated as a specific example of a steam consumption apparatus, a steam consumption apparatus is not limited to the heat exchanger 4. FIG. As long as it is a device that uses the supplied steam in some form to discharge drain, its form and application are not limited. Further, a plurality of identical or different steam consuming devices may be connected in parallel or in series.

  Further, although the cascade tank 5 is illustrated as a specific example of the water supply tank, the water supply tank is not limited to the cascade tank 5. That is, the partition plate 5a is not an essential component. Needless to say, the sight glass 5d, the filter device 5e, the safety valve 5f, the pressure regulating valve 10 and the like are not essential components.

  In the above embodiment, the drain cooler 6 and the buffer tank 12 are opened to the atmosphere, that is, the internal pressure of the drain cooler 6 and the buffer tank 12 is maintained at atmospheric pressure. It is not limited to such a configuration. The drain cooler 6 and the buffer tank 12 may be sealed with respect to the atmosphere. In this case, the internal pressure of the drain cooler 6 and the buffer tank 12 needs to be equal to or lower than the internal pressure of the cascade tank 5, but is preferably lower than the internal pressure of the cascade tank 5. This is because the flash steam is guided to the drain cooler 6.

  The buffer tank 12 may be omitted, and the water condensed by the drain cooler 6 may flow directly into the cascade tank 5. In this case, the supplementary water pipe 13 may be connected to the cascade tank 5 or may be connected to the auxiliary boiler 3.

  The transfer pump 14 and the water supply pump 16 are not essential components. For example, if the cascade tank 5 is arranged higher than the auxiliary boiler 3 and the buffer tank 12 is arranged higher than the cascade tank 5, canned water or the like can be transferred by gravity, so the transfer pump 14 and the water supply pump 16 are omitted. Can do. In this case, a valve may be arranged in place of the transfer pump 14 and the water supply pump 16 to open and close as necessary.

  Needless to say, it is optional to add a device, such as a pump, a valve, or a sensor, not shown in the above embodiment, as necessary.

DESCRIPTION OF SYMBOLS 1 Steam plant 2 Drain collection device 3 Auxiliary boiler 4 Heat exchanger 5 Cascade tank 5a Partition plate 5b 1st chamber 5c 2nd chamber 5d Sight glass 5e Filter device 5f Safety valve 5g, 5h, 5i Limit switch 6 Drain cooler 7 Drain introduction pipe 8 Steam trap 9 Steam discharge pipe 10 Pressure adjustment valve 11 Condensate recovery pipe 12 Buffer tanks 12a and 12b Limit switch 13 Refill pipe 14 Transfer pump 15 Water supply pipe 16 Water supply pump 17 Surplus steam recovery pipe 18 Pressure adjustment valve

Claims (4)

A water tank sealed against the atmosphere;
A cooler that condenses and discharges the steam;
A drain introduction conduit for leading drain discharged from the steam consuming equipment to the water supply tank;
A steam discharge line for discharging flash steam generated from the drain from the water supply tank and leading to the cooler;
In the cooler, Bei give a condensate recovery pipe for guiding the water in which the flash vapor produced is condensed on the water supply tank,
The water supply tank includes a partition plate that divides the water supply tank into a first chamber and a second chamber at a portion higher than the liquid level of the drain stored in the water supply tank,
The drain introduction conduit is connected to the water supply tank in the first chamber,
The steam discharge line is connected to the water supply tank in the second chamber;
Furthermore, a communication pipe line connecting the first chamber and the second chamber is provided,
A drain recovery device comprising a filter device for removing oil in the steam in the middle of the connecting pipe . The partition plate is a hanging wall that hangs down from the top plate of the water supply tank,
The drain recovery device according to claim 1, wherein a lower end of the drooping wall is configured to be submerged below the liquid level of the drain stored in the water supply tank . The water supply tank includes first and second limit switches for detecting a liquid level height,
The first and second limit switches are both arranged at a height between the upper end and the lower end of the hanging wall,
The said 1st limit switch is above the said 2nd limit switch, and is arrange | positioned at intervals in the up-down direction with respect to the said 2nd limit switch. Drain collection device. A buffer tank that is disposed in the middle of the condensate recovery pipeline and temporarily stores water delivered from the cooler;
A transfer pump for transferring water stored in the buffer tank to the water supply tank;
The transfer pump is activated when the second limit switch no longer detects the liquid level, and then when the liquid level in the water supply tank rises and the first limit switch detects the liquid level The drain recovery device according to claim 3 , wherein the drain recovery device is stopped .

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