JP7168824B1 - heat recovery system - Google Patents

Abstract

A heat recovery system (100) includes a header tank (2) in which drain generated in the steam-using equipment is stored, a heat exchanger (4) in which flash steam of the drain exchanges heat with an object, and a drain from the steam-using equipment. and a recovery pipe (10) for recovering the flash steam, the drain of the recovery pipe (10) and the flash steam are separated and flowed into the header tank (2) and the heat exchanger (4). (1). The gas-liquid separation section (1) includes a flash vapor gas pipe (12) extending vertically upward from the end of the recovery pipe (10) and connected to the heat exchanger (4), and the end of the recovery pipe (10). and a drain liquid pipe (11) bent vertically downward from the head portion and connected to the header tank (2).

Description

The technology of the present disclosure relates to heat recovery systems.

As a heat recovery system, for example, as disclosed in Patent Document 1, there is known a drain recovery device that recovers in a header tank drain generated by condensation of steam in a steam-using device. In this drain recovery device, the drain of the header tank is supplied to the utilization side and utilized, thereby recovering the heat of the drain.

WO2016/056481

By the way, in the drain recovery apparatus as described above, there is a demand for recovering not only the drain but also the flush steam (steam, etc.) of the drain from the viewpoint of energy efficiency. In that case, it is conceivable to install a heat exchanger for heat recovery of the flash steam, let the drain flow into the header tank, and let the flash steam flow into the heat exchanger. However, since the heat exchanger generally has a larger pressure loss than the header tank, the flash steam flows into the header tank together with the drain. Then, not only it becomes difficult to recover the heat of the flash steam, but also the recovery amount of the drain decreases.

The technology of the present disclosure has been made in view of such circumstances, and an object thereof is to provide a heat recovery system capable of recovering heat by separating drain and flash steam.

A heat recovery system of the present disclosure includes a header tank, a heat exchanger, and a gas-liquid separator. The header tank stores drain generated in the steam-using equipment. In the heat exchanger, the flash vapor of the drain exchanges heat with the object. The gas-liquid separation unit has a recovery pipe for recovering the drain and flash steam from the steam-using equipment, separates the drain and flash steam in the recovery pipe, and supplies them to the header tank and the heat exchanger. let it flow in. The gas-liquid separation unit includes the flash vapor gas pipe extending vertically upward from the end of the recovery pipe and connected to the heat exchanger, and the gas-liquid separation unit bending vertically downward from the end into a U shape. and a liquid pipe for the drain connected to the header tank.

According to the heat recovery system of the present disclosure, drain and flash steam can be separated for heat recovery.

FIG. 1 is a piping system diagram showing a schematic configuration of a heat recovery system. FIG. 2 is a cross-sectional view showing a schematic configuration of the liquid pumping device. FIG. 3 is a schematic configuration diagram of a gas-liquid separation unit.

Hereinafter, embodiments of the present application will be described with reference to the drawings. The following embodiments are essentially preferred examples, and are not intended to limit the scope of the technology disclosed in the present application, its applications, or its uses.

The heat recovery system 100 of the present embodiment recovers drain generated by condensation of steam in steam-using equipment and flash steam (eg, steam) of the drain. That is, the heat recovery system 100 recovers the heat of the hot drain and the heat of the flash steam.

As shown in FIG. 1 , the heat recovery system 100 includes a gas-liquid separator 1 , a header tank 2 , a heat exchanger 4 and a liquid pumping device 5 .

The gas-liquid separation unit 1 has a recovery pipe 10 for recovering drain and flash steam from steam-using equipment (not shown), and separates the drain and flash steam in the recovery pipe 10 to separate them into the header tank 2 and the heat exchanger. Flow into 4. Specifically, the gas-liquid separation unit 1 has a recovery pipe 10 , a liquid pipe 11 and a gas pipe 12 .

Drain generated in steam-using equipment and its flash steam flow into the recovery pipe 10 . The liquid pipe 11 and the gas pipe 12 are branch pipes obtained by branching the recovery pipe 10 into two. Of the drain and flash steam that have flowed into the recovery pipe 10 , the drain flows into the liquid pipe 11 and the flash steam flows into the gas pipe 12 . The gas pipe 12 is a straight pipe extending vertically upward from the end of the recovery pipe 10 . The gas pipe 12 is connected to the heat exchanger 4 and allows flash steam to flow into the heat exchanger 4 . The liquid tube 11 extends downward from the end of the recovery tube 10 . The liquid pipe 11 is connected to the header tank 2 and allows drain to flow into the header tank 2 . Details of the gas-liquid separation unit 1 will be described later.

The header tank 2 is a water-sealed header tank into which the drain generated by the steam-using equipment flows and is stored. Specifically, the header tank 2 has a container-like tank body 21 and an overflow pipe 24 .

The internal space of the tank body 21 is divided into a liquid phase portion 22 of drain and a gas phase portion 23 of steam. The tank main body 21 is connected to the liquid pipe 11, the outflow pipe 13 and the inflow pipe 16a. The liquid pipe 11 opens to the gas phase portion 23 . The outflow pipe 13 is connected to the top of the tank body 21 and opens to the gas phase portion 23 . The inflow pipe 16 a opens to the liquid phase portion 22 . Drain flows from the liquid pipe 11 and is stored in the tank body 21 . In the tank main body 21, the drain from the heat exchanger 4 flows through the outflow pipe 13 and is stored. In the tank main body 21, the drain of the liquid phase portion 22 flows into the liquid pumping device 5 through the inflow pipe 16a. One end of the overflow pipe 24, which is an inflow end, opens to the liquid phase portion 22, and the other end, which is an outflow end, penetrates the upper side wall of the tank body 21 and opens to the atmosphere.

The internal space of the tank body 21 is sealed by the water seal of the water seal trap 3 . Specifically, the water seal trap 3 is connected to the tank body 21 by a connection pipe 15a and an outflow pipe 15b. The connection pipe 15 a has one end, which is an inflow end, opened to the gas phase portion 23 of the tank body 21 , and the other end, which is an outflow end, is opened to the sealing water of the water seal trap 3 . That is, the other end of the connection pipe 15a is water sealed. The outflow pipe 15 b has one inflow end connected to the water seal trap 3 and the other outflow end opening to the liquid phase portion 22 of the tank body 21 . The water seal trap 3 normally prevents the steam from leaking out of the tank body 21 by means of a water seal. escape to the atmosphere. Further, in the water seal trap 3, excess drain generated by condensation of steam flows into the tank main body 21 through the outflow pipe 15b and is stored therein.

The heat exchanger 4 has a first channel 41 and a second channel 42 which are internal channels. The first flow path 41 is a heat exchange flow path through which flush steam from the drain flowing into the header tank 2 from the steam-using equipment is introduced to exchange heat with an object (for example, water) in the second flow path 42 . More specifically, the gas pipe 12 is connected to the inflow end of the first flow path 41 , and the outflow pipe 13 is connected to the outflow end of the first flow path 41 . The second flow path 42 is connected to an inflow pipe 14 a for supplying water and an outflow pipe 14 b for outflowing water from the second flow path 42 . In the heat exchanger 4, the flash steam in the first flow path 41 exchanges heat with the water in the second flow path 42 to heat the water. The flash steam condenses and becomes drain. Thus, heat recovery of the flash steam is performed.

Also, the heat recovery system 100 causes the flash steam to exchange heat with an object in the heat exchanger 4 to flow condensed drain into the header tank 2 . That is, the drain generated in the first flow path 41 flows into the header tank 2 through the outflow pipe 13 . Therefore, it is possible to recover the heat of the drain generated by the condensation of the flash steam.

The liquid pumping device 5 is a pump that supplies the drain stored in the header tank 2 to a point of use. The liquid pressure-feeding device 5 alternately performs an inflow operation of flowing the drain of the header tank 2 into the storage chamber 51 and a pressure-feeding operation of pressure-feeding the drain of the storage chamber 51 to the use location. As shown in FIG. 2 , the liquid pumping device 5 includes a casing 50 that is a closed container, an air supply valve 56 and an exhaust valve 57 , and a valve operating mechanism 58 .

The casing 50 has a body portion 50a and a lid portion 50b which are connected by bolts, and a drain storage chamber 51 is formed therein. The lid portion 50b is provided with an inflow port 52 for drain inflow, a pumping port 53 for pumping the drain, an air supply port 54 for supplying the working gas, and an exhaust port 55 for discharging the working gas. ing. These inflow ports 52 and the like are all provided in the lid portion 50b and communicate with the storage chamber 51. As shown in FIG. The inflow port 52 is connected to the inflow pipe 16a, the pressure feed port 53 is connected to the pressure feed pipe 16b, the air supply port 54 is connected to the air supply pipe 16c, and the exhaust port 55 is connected to the exhaust pipe 16d. . The air supply pipe 16 c supplies high-temperature, high-pressure steam generated by, for example, a boiler in the steam system to the air supply port 54 . The exhaust pipe 16 d is connected to the outflow pipe 13 . The pressure-feeding pipe 16b supplies the drain from the pressure-feeding port 53 to a predetermined utilization point. Thereby, the heat of the high-temperature drain stored in the header tank 2 is recovered.

The air supply valve 56 is provided in the air supply port 54 and opens and closes the air supply port 54 . The exhaust valve 57 is provided at the exhaust port 55 and opens and closes the exhaust port 55 . A valve operating rod 57 a is connected to the lower portion of the exhaust valve 57 . A connecting plate 57b extending to a region below the air supply valve 56 is attached to the valve operating rod 57a. According to this configuration, when the valve operating rod 57 a rises, the air supply valve 56 opens the air supply port 54 and the exhaust valve 57 closes the exhaust port 55 . When the valve operating rod 57 a descends, the air supply valve 56 closes the air supply port 54 while the exhaust valve 57 opens the exhaust port 55 .

The valve operating mechanism 58 is provided inside the casing 50 and operates the intake valve 56 and the exhaust valve 57 by vertically moving a valve operating rod 57a. The valve actuation mechanism 58 has a float 581 and a snap mechanism 59 .

The float 581 is spherical and has a lever 582 attached thereto. Lever 582 is rotatably supported by shaft 583 provided on bracket 584 . A shaft 585 is provided at the end of the lever 582 opposite to the float 581 side. The snap mechanism 59 has a float arm 591, a sub arm 592, a coil spring 593, and two receiving members 594a, 594b. One end of the float arm 591 is rotatably supported by a shaft 596 provided on a bracket 597 . A groove 591a is formed in the other end of the float arm 591, and the shaft 585 of the lever 582 is fitted in the groove 591a. With this configuration, the float arm 591 swings around the shaft 596 as the float 581 rises and falls.

Also, the float arm 591 is provided with a shaft 595a. The secondary arm 592 has an upper end rotatably supported by a shaft 596 and a lower end provided with a shaft 595b. The receiving member 594a is rotatably supported by the shaft 595a of the float arm 591, and the receiving member 594b is rotatably supported by the shaft 595b of the sub arm 592. As shown in FIG. A compressed coil spring 593 is attached between the receiving members 594a and 594b. Further, the sub arm 592 is provided with a shaft 598 to which the lower end of the valve operating rod 57a is connected.

In the liquid pumping device 5 , the float 581 is positioned at the bottom of the storage chamber 51 when the storage chamber 51 is not filled with drain. In this state, the valve operating rod 57a is lowered, the intake valve 56 is closed, and the exhaust valve 57 is open. As the drain flows from the inflow port 52 and accumulates in the storage chamber 51, the float 581 rises. On the other hand, in the storage chamber 51, steam is discharged from the exhaust port 55 to the exhaust pipe 16d as the drain accumulates. The steam discharged to the exhaust pipe 16 d flows into the header tank 2 through the outflow pipe 13 . Thus, the inflow operation is performed. That is, in the inflow operation, gas-liquid replacement (that is, replacement of the drain of the header tank 2 with the steam of the liquid pressure-feeding device 5) is performed between the header tank 2 and the liquid pressure-feeding device 5. FIG. When the drain water level in the storage chamber 51 reaches a predetermined high water level, the snap mechanism 59 raises the valve operating rod 57a. As a result, the air supply valve 56 is opened and the exhaust valve 57 is closed.

When the air supply valve 56 opens, working gas (high-pressure steam) is supplied from the air supply port 54 and introduced into the upper portion of the storage chamber 51 (the space above the drain). Then, the drain accumulated in the storage chamber 51 is pushed downward by the pressure of the introduced steam and is pressure-fed from the pressure-feed port 53 . Thus, the pumping operation is performed. When the drain water level in the storage chamber 51 drops due to this pumping operation, the float 581 descends. When the drain water level in the storage chamber 51 reaches a predetermined low level, the snap mechanism 59 lowers the valve operating rod 57a. As a result, the air supply valve 56 is closed and the exhaust valve 57 is opened. In this way, the inflow operation and the pumping operation are alternately performed.

Next, details of the gas-liquid separator 1 will be described with reference to FIG. 3 as well. The liquid tube 11 is a so-called U-shaped tube bent vertically downward from the end of the recovery tube 10 . Specifically, the liquid tube 11 has a first tube 11a, a second tube 11b, a third tube 11c and a fourth tube 11d.

The first pipe 11a is a straight pipe extending vertically downward from the end of the recovery pipe 10 . The second pipe 11b is a pipe that is connected to the lower end of the first pipe 11a and forms a U-shaped bottom. More specifically, the second pipe 11b is a straight pipe extending horizontally from the lower end of the first pipe 11a. The third pipe 11c is a straight pipe extending vertically upward from the end of the second pipe 11b. That is, the first pipe 11a and the third pipe 11c extend parallel to each other in the vertical direction. The fourth pipe 11d is a straight pipe extending horizontally from the upper end of the third pipe 11c. The fourth pipe 11d is connected to the side of the header tank 2 (more precisely, the tank body 21).

In the liquid pipe 11, the heights of the first pipe 11a and the third pipe 11c are such that the head difference H generated between the first pipe 11a and the third pipe 11c due to the pressure loss in the heat exchanger 4 can be secured. set to a value.

Specifically, in the liquid pipe 11, drain stays in the first pipe 11a, the second pipe 11b, and the third pipe 11c, and is water-sealed by the staying drain. The liquid pipe 11 is water-sealed to prevent flash steam from flowing into the header tank 2 through the liquid pipe 11 .

More specifically, in the third pipe 11c, the drain stays up to the upper end, while in the first pipe 11a, the drain head is lower than that of the third pipe 11c. That is, a drain head difference H is generated between the first pipe 11a and the third pipe 11c. This head difference H is caused by pressure loss in the heat exchanger 4 . The pressure loss in the heat exchanger 4 is offset by the water head difference H thus generated. The first pipe 11 a and the third pipe 11 c are set to have a height sufficient to ensure a water head difference H corresponding to the pressure loss of the heat exchanger 4 . Therefore, the pressure loss of the heat exchanger 4 can be reliably offset. Thereby, flash steam can be easily made to flow into the heat exchanger 4 from the gas pipe 12 .

As described above, the heat recovery system 100 of the embodiment includes the header tank 2 , the heat exchanger 4 , and the gas-liquid separator 1 . The header tank 2 stores the drain generated by the equipment using steam. In the heat exchanger 4, the flash vapor of the drain exchanges heat with the object. The gas-liquid separation unit 1 has a recovery pipe 10 for recovering drain and flash steam from the steam-using equipment, and separates the drain and flash steam in the recovery pipe 10 to flow into the header tank 2 and the heat exchanger 4. . The gas-liquid separation unit 1 includes a flash vapor gas pipe 12 extending vertically upward from the end of the recovery pipe 10 and connected to the heat exchanger 4, and a U-shaped pipe extending vertically downward from the end of the recovery pipe 10. and a drain liquid pipe 11 that is bent toward the header tank 2 and connected to the header tank 2 .

According to the above configuration, the drain separated by the gas-liquid separator 1 flows through the liquid pipe 11 into the header tank 2 , and the flash steam flows into the heat exchanger 4 through the gas pipe 12 . The drain of the header tank 2 is sent to the utilization side, and the heat of the drain is recovered. The heat of the flash steam is recovered by exchanging heat with the object in the heat exchanger 4 to heat the object. Since the liquid pipe 11 is bent in a U-shape, the drain stays and is water-sealed. The liquid pipe 11 is water-sealed to prevent flash steam from flowing into the header tank 2 through the liquid pipe 11 . Therefore, drain and flash steam can be separated for heat recovery.

Further, in the heat recovery system 100 of the above embodiment, the liquid pipe 11 is connected to the first pipe 11a extending vertically downward from the end of the recovery pipe 10 and the first pipe 11a to form a U-shaped bottom. It has a second pipe 11b and a third pipe 11c extending vertically upward from the second pipe 11b. The heights of the first pipe 11a and the third pipe 11c are set to a value that can ensure the head difference H between the first pipe 11a and the third pipe 11c due to the pressure loss in the heat exchanger 4 .

According to the above configuration, even if pressure loss occurs in the heat exchanger 4, the pressure loss can be offset with certainty. Therefore, the flash steam can be easily made to flow into the heat exchanger 4 from the gas pipe 12 . Therefore, the drain and flash steam can be more reliably separated for heat recovery.

Also, the heat recovery system 100 of the above-described embodiment causes the flash steam to exchange heat with the target object in the heat exchanger 4 to flow condensed drain into the header tank 2 .

According to the above configuration, it is also possible to recover heat from drain generated by condensation of flash steam in the heat exchanger 4 .

As described above, the technology of the present disclosure is useful for heat recovery systems.

100 heat recovery system 1 gas-liquid separator 2 header tank 4 heat exchanger 10 recovery pipe 11 liquid pipe 11a first pipe 11b second pipe 11c third pipe 12 gas pipe H head difference

Claims (2)

a header tank in which drain generated by steam-using equipment is stored;
a heat exchanger for heat-exchanging the flash steam of the drain with an object;
a gas-liquid separation unit having a recovery pipe for recovering the drain and flash steam from the steam-using equipment, separating the drain and flash steam in the recovery pipe and allowing them to flow into the header tank and the heat exchanger; with
The gas-liquid separation unit includes a gas pipe for the flash steam extending vertically upward from the end of the recovery pipe and connected to the heat exchanger, and a gas pipe for the flash steam that is bent vertically downward from the end to form the and a liquid pipe of the drain connected to the header tank ,
The liquid pipe includes a first pipe extending vertically downward from the end, a second pipe connected to the first pipe and forming the bottom of the U-shape, and a second pipe extending vertically upward from the second pipe. 3 tubes,
The heights of the first pipe and the third pipe are set to a value that can ensure a head difference between the first pipe and the third pipe due to pressure loss in the heat exchanger.
A heat recovery system characterized by: In the heat recovery system of claim 1 ,
A heat recovery system, wherein the flash steam exchanges heat with an object in the heat exchanger, and condensed drain is allowed to flow into the header tank.

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