JP6691385B2 - Drain outlet temperature control system and boiler system - Google Patents

Description

  The present invention relates to a drain outlet temperature adjusting system and a boiler system applicable to a boiler system of a ship or the like.

  Heavy oil is used as fuel oil for the main engine mounted on ships. Since the viscosity of heavy oil is high, it is necessary to heat it with a heater to reduce the viscosity. Therefore, the conventional boiler system 100 shown in FIG. 6 is used. The boiler system 100 includes a boiler 52, a cascade tank 56 that stores water supply 54, and a heater 58a.

  The boiler 52 includes an exhaust heat recovery boiler 62 including a heat exchange section 60. The exhaust heat of the main machine 64 is sent from the exhaust pipe 66 to the exhaust heat recovery boiler 62, and the feed water 54 sent to the heat exchange section 60 is heated. The steam generated by heating the water supply 54 is sent to the heater 58a.

  Fuel (heavy oil) of the main engine 64 is supplied from a fuel tank 68 through a fuel pipe 70. A heater 58 a having a heat exchange section 72 is provided in the middle of the fuel pipe 70. The heater 58a heats the fuel and reduces the viscosity. The reduced viscosity fuel is supplied to the main machine 64.

  The vapor obtained by heating the fuel with the heater 58a is condensed into a high-temperature drain, which is cooled with the drain cooler 102 to a predetermined temperature. The cooled drain is returned to the cascade tank 56 and then heated again in the boiler 52.

  It is necessary to reliably cool the high temperature drain to a predetermined temperature by the drain cooler 102. Therefore, the cooling capacity of the drain cooler 102 is designed based on the maximum heat amount of the drain put in the drain cooler 102. Moreover, the temperature of the cooling water (seawater) of the drain cooler 102 is designed to be the water temperature of the equator (for example, 32 ° C.).

  However, since the cooling capacity of the drain cooler 102 is based on the maximum amount of heat of the drain, the temperature of the drain when entering the drain cooler 102 is often lower than the predetermined temperature. Moreover, the temperature of the cooling water is often lower than the predetermined temperature. Therefore, the temperature of the drain returned to the cascade tank 56 often becomes low. As much as it becomes lower, it is necessary to heat the boiler 52 or heat it before supplying water to the boiler 52. The larger the heating amount, the worse the boiler efficiency.

  As shown in FIG. 7, the following Patent Document 1 discloses a boiler system 110 that controls the temperature of the condensate 54 of the cascade tank 56. In Patent Document 1, a three-way valve 112 is provided in a pipe through which a high temperature drain flows, and the drain cooler 102 or the cascade tank 56 can be selected. The temperature of the condensate water 54 in the cascade tank 56 is measured by the temperature sensor 114. If the temperature is low, the three-way valve 112 is switched, and the high temperature drain is directly supplied to the cascade tank 56. The temperature of the condensate 54 can be raised by the high temperature drain.

  However, the piping is connected from the three-way valve 112 to the cascade tank 56, and the piping connection is different from the conventional one, which may complicate the design.

  Further, heavy fuel oil C used as a ship fuel always contains a small amount of sulfur and hydrogen, and when it is burned, steam and sulfur dioxide are generated. At that time, a part of the sulfurous acid gas, usually 1 to 2%, and a maximum of about 4% is converted to sulfuric anhydride. Sulfuric acid anhydride combines with water vapor in the combustion gas to form water vapor of sulfuric acid, which condenses at temperatures below the dew point temperature and causes severe low temperature corrosion. When the exhaust gas of the diesel engine (main engine 64) becomes 400 ° C. or higher, it combines with nitrogen in the air to form nitrogen oxides, so NOx regulations are introduced, and the temperature of the exhaust gas tends to be designed as low as possible. If the exhaust gas temperature is lower than 200 ° C., low temperature corrosion is likely to occur due to the above condensation, and as a countermeasure against this, it is necessary to raise the temperature of the water supplied to the boiler 52.

JP, 2014-163632, A

  It is an object of the present invention to provide a drain outlet temperature adjusting system and a boiler system that can prevent low temperature corrosion without complicating the design.

  The drain outlet temperature adjusting system of the present invention includes a drain cooler, a first pipe, a seal pot, a second pipe, a temperature sensor, and a valve. Drain, steam, or both are supplied to the drain cooler from the first pipe at the inlet of the first pipe. They are cooled and fed to the seal pot. The temperature of the drain of the seal pot is measured, the valve is opened and closed according to the temperature, and drain, steam, or both are supplied from the second pipe to the drain cooler. Further, the boiler system of the present invention uses the above drain outlet temperature adjusting system.

  According to the present invention, only by applying the present invention to the conventional boiler system, it is possible to supply water to the boiler at an appropriate temperature, without complicating the design. Since the temperature control is completed by the system of the present application and the piping design is not complicated unlike the conventional system, space saving can be achieved. The temperature of the cascade tank can be kept high, and the temperature of the water supplied to the boiler can be raised. Even if the temperature of the exhaust gas falls below 200 ° C., low temperature corrosion can be prevented.

It is a figure which shows the structure of the drain outlet temperature adjustment system of this invention. It is a figure which shows the structure of the outlet vicinity of a drain cooler, (a) is a figure which shows the positional relationship of the opening of a drain cooler, and a water level adjustment pipe, (b) shows the positional relationship of a 2nd piping and a water level adjustment tube. FIG. It is a figure which shows the structure which integrated the drain outlet temperature control system of this invention into the boiler system. It is a figure which shows the structure of the drain outlet temperature control system which uses the three-way valve of this invention. It is a figure which shows the structure which integrated the drain outlet temperature control system of this invention of FIG. 4 in the boiler system. It is a figure which shows the structure of the conventional boiler system. It is a figure which shows the structure of the conventional boiler system which uses a three-way valve.

  A drain outlet temperature adjusting system and a boiler system of the present invention will be described with reference to the drawings. The case where the drain outlet temperature adjustment system is incorporated in the boiler system of a ship will be described as an example, but it may be applied to other boiler systems.

  The drain outlet temperature adjusting system 10 shown in FIG. 1 includes a first pipe 16 connected to the inlet 14 of the drain cooler 12, a second pipe 22 connected to a seal pot 20 at the outlet 18 of the drain cooler 12, and a seal. A water level adjusting pipe 24 connected to the pot 20, a temperature sensor 26 for measuring the temperature of the drain of the seal pot 20, and a valve 28 provided in the second pipe 22 are provided.

The drain cooler 12 includes a cylindrical casing 30, a baffle (not shown) in the casing 30, and a pipe (not shown) through which cooling water passes. A baffle plate is arranged in the housing 30 so that a drain or the like can meander in a horizontal direction, and a pipe through which cooling water passes is extended while penetrating the baffle plate. The baffle causes drain, steam, or both to move in the housing 30 while meandering in the horizontal direction. While the drain or the like is proceeding, the drain or the like is cooled by the cooling water. Cooling water uses seawater or fresh water. It should be noted that the drain cooler 12 and the seal pot 20 in FIG. 1 do not show the first pipe 16 and the second pipe 22, but schematically show the flow of drain and the like.
The cooling capacity of the drain cooler 12 is designed based on the maximum heat quantity of the drain. For example, the hot drain is designed to be cooled to a predetermined temperature of 60 to 75 ° C. In addition, the temperature of the cooling water is designed based on the seawater temperature of the equator (for example, 32 ° C.) so that the high temperature drain can be cooled in any region. Make sure that the drain cooler 12 can cool the drain.

  The discharge pipe 31 is branched into a first pipe 16 and a second pipe 22. Then, the first pipe 16 is connected to the inlet portion 14 of the drain cooler 12. The first pipe 16 is connected to a heater or the like, and a high temperature drain, steam, or both are supplied from the heater or the like to the drain cooler 12 through the first pipe 16. The steam is cooled by the drain cooler 12 and condensed to become drain. The hot drain is cooled with cooling water.

  The valve 32 may be provided in the middle of the first pipe 16. In FIG. 1, the valve 32 is provided from the branch position of the first pipe 16 and the second pipe 22 to the drain cooler 12. The valve 32 controls the flow of drain or the like. The valve 32 is opened and closed according to the temperature of the drain flowing through the first pipe 16 and the cooling capacity of the drain cooler 12, and the amount of drain supplied to the drain cooler 12 is adjusted. The opening / closing of the valve 32 may be determined at the design stage, and the opening / closing degree may be fixed.

  As shown in FIG. 2A, an opening 34 is provided at the lower end of the housing 30 of the drain cooler 12 at the downstream end where the drain and the like meander. The housing 30 and the box-shaped seal pot 20 are connected via an opening 34, and the cooled drain 36 is supplied to the seal pot 20 from the opening 34. In FIG. 2, the flow of the drain 36 is indicated by an arrow, and goes from the opening 34 to the inlet 40 of the water level adjusting pipe 24.

  The second pipe 22 branches from the first pipe 16 and is connected to the seal pot 20. Further, as shown in FIG. 2B, an opening 38 for connecting the seal pot 20 and the drain cooler 12 to each other so as to have the same pressure is provided. When the drain cooler 12 cools the drain and the like, the drain cooler 12 has a negative pressure, and the seal pot 20 has a negative pressure, and the high temperature drain and / or steam from the second pipe 22 to the seal pot 20. Enter as if sucked. By supplying a high temperature drain or the like directly to the seal pot 20 from the second pipe 22, the temperature of the drain 36 of the seal pot 20 can be raised.

  The inner diameter of the second pipe 22 is determined by the temperature of the drain or the like flowing through the first pipe 16 when designing the drain outlet temperature adjustment system 10. The inner diameter of the second pipe 22 is reduced as the temperature of the drain or the like flowing through the first pipe 16 increases. This is because as the temperature of the drain or the like is higher, it is necessary to cool the drain or the like by the drain cooler 12, and it becomes less necessary to supply the drain or the like having a high temperature from the second pipe 22 to the seal pot 20. In addition to controlling the flow rate of drain or the like by the valve 28 described later, the flow rate of drain or the like is controlled also by the inner diameter of the second pipe 22.

  A water level adjusting pipe 24 is arranged in the seal pot 20. The drain 36 is supplied from the seal pot 20 to the cascade tank through the water level adjusting pipe 24. The position of the inlet 40 of the water level adjusting pipe 24 becomes the water level of the drain cooler 12 and the drain 36 of the seal pot 20. Since the opening 38 is located higher than the inlet 40, the drain does not enter the seal pot 20 through the opening 38, and the drain cooler 12 and the seal pot 20 can have the same pressure.

  The temperature sensor 26 is arranged in the seal pot 20. The temperature of the drain 36 supplied to the cascade tank is measured. In the seal pot 20, the drain and the like from the drain cooler 12 and the drain and the like from the second pipe 22 are mixed uniformly, so that the opening 34 of the drain cooler 12, the outlet 42 of the second pipe 22, and the inlet of the water level adjusting pipe 24. Determine 40 positions. The temperature sensor 26 measures the temperature in a state where the drain and the like are mixed and uniform.

  The valve 28 of the second pipe 22 may be a temperature control valve combined with the temperature sensor 26. The valve 28 is proportionally controlled by the temperature. If the temperature of the drain 36 is lower than the predetermined temperature, the valve 28 is opened by an amount corresponding to the temperature difference. That is, the lower the temperature of the drain 36 is below the predetermined temperature, the larger the opening degree of the valve 28. The opening amount of the valve 28 controls the flow amount of high-temperature drain or the like.

  Instead of using the temperature control valve, the opening / closing of the valve 28 may be controlled by PID (Proportional-Integral-Derivative) control or the like.

  As shown in FIG. 2B, the second positions of the second pipe 22 and the water level adjusting pipe 24 in the seal pot 20 are displaced from each other in the horizontal direction. This is because high temperature drain or the like does not reach the water level adjusting pipe 24 directly from the second pipe 22. Further, the position of the inlet 40 of the water level adjusting pipe 24 is higher than the position of the opening 34 of the drain cooler 12 and the outlet 42 of the second pipe 22. The drain 36 is discharged from the water level adjusting pipe 24 in a state where the drain cooler 12 and the drain or the like supplied from the second pipe 22 are mixed. The high temperature drain or the like is not directly supplied from the second pipe 22 to the cascade tank.

  The position of the temperature sensor 26 may be appropriately changed depending on the shape of the drain cooler 12, the shape of the seal pot 20, and the like. Since the temperature of the drain put in the cascade tank has a predetermined range, it is not necessary to measure the temperature of the drain 36 in a 100% mixed state.

  The flow of drain and the like by the drain outlet temperature adjustment system 10 of the present application will be described. First, the valve 28 of the second pipe 22 is closed.

  (1) A drain or the like is supplied from the first pipe 16 to the drain cooler 12 to cool it. The temperature of the drain 36 that has entered the seal pot 20 from the drain cooler 12 is measured, and if it is a predetermined temperature, the valve 28 of the second pipe 22 remains closed.

  (2) If the temperature of the drain 36 of the seal pot 20 is lower than a predetermined temperature, the valve 28 is opened and the drain or the like is supplied from the second pipe 22 to the seal pot 20. Drain or the like is supplied to the seal pot 20 from the second pipe 22 in addition to the drain cooler 12, and the temperature of the drain 36 of the seal pot 20 rises.

  (3) When the temperature of the drain 36 of the seal pot 20 reaches a predetermined temperature by the above (2), the opening degree of the valve 28 becomes constant in order to maintain the temperature.

  As described above, the temperature of the drain 36 of the seal pot 20 can be set to a predetermined temperature by opening / closing the valve 28.

  Next, a case where the present application is incorporated into a boiler system of a ship will be described. As shown in FIG. 3, the boiler system 50 includes a boiler 52, a cascade tank 56 for storing condensed water 54 for generating steam in the boiler 52, a pump P for circulating the condensed water 54, and a boiler 52. A heater 58a using steam as a heat source is provided.

  The boiler 52 includes a heat exchange section 60 through which condensate 54 flows, an exhaust heat recovery boiler 62 having the heat exchange section 60 housed therein, and an exhaust pipe 66 for guiding the exhaust heat gas of the main machine 64 to the exhaust heat recovery boiler 62. . The main engine 64 is provided in the ship and includes a diesel engine driven by C heavy oil. The exhaust heat gas of the main machine 64 is sent to the exhaust heat recovery boiler 62, and the condensate water 54 is heated in the heat exchange section 60 to become steam.

  The fuel is heated by the following configuration to reduce the viscosity and the fuel is supplied to the main engine 64. A fuel tank 68 for storing fuel (heavy oil, etc.), a fuel pipe 70 for supplying fuel from the fuel tank 68 to the main engine 64, and a heater 58a provided in the middle of the fuel pipe 70 and having a heat exchange section 72 are provided. The fuel in the fuel tank 68 is supplied to the heat exchange section 72 of the heater 58a to be heated and supplied to the main machine 64. The heat source of the heater 58a uses steam generated by heating the condensed water 54.

  A heater 58b other than the heater 58a for heating the fuel supplied to the main engine 64 may be provided. Examples of the heater 58b include a fuel oil heater for a cleaner, a lubricating oil heater, a service tank fuel heater, a set ring tank fuel heater, and a fresh water heater. The heat source of these heaters 58b is also steam generated by heating the condensed water 54.

  Further, steam may be sent to the tank heating 58c to keep the temperature of the liquid cargo constant, or steam may be sent to the tank cleaning heater 58d to heat seawater or fresh water for cleaning the tank.

  The high temperature drain after being used in the heater 58 and the like is supplied to the first pipe 16 and the second pipe 22 through the discharge pipe 31.

  Although the number of heaters 58a, 58b and the like is increased compared to the conventional boiler systems 100, 110 of FIGS. 6 and 7, the number of heaters 58a, 58b and the like may be increased in the conventional systems 100, 110 as well. The system 50 is not complicated.

  The steam is used by the heater 58a or the like to become a high-temperature drain, which is supplied to the drain cooler 12. In addition, some steam may be supplied to the drain cooler 12 as it is without being drained. When steam is generated too much and the pressure rises, the surplus steam adjusting valve 74 is opened to guide the steam to the drain cooler 12. The drain that has reached a predetermined temperature in the drain cooler 12 is returned to the cascade tank 56 and stored as the condensate water 54. When the temperature of the drain cools down in the drain cooler 12, the high temperature drain or the like is supplied to the outlet of the drain cooler 12 to raise the temperature of the drain as described above.

  In the present invention, the temperature-controlled drain 36 can be supplied to the cascade tank 56 as the condensate 54. Since the drain 36 having a predetermined temperature is supplied to the cascade tank 56, it is not necessary to heat the boiler feed water, and the thermal efficiency of the boiler 52 is good. The temperature control is completed by the drain outlet temperature control system 10, and other piping can be used as it is. The design of the boiler system 50 does not become complicated and the space can be saved. The temperature of the water supplied to the boiler 52 can be kept high, which is a measure against low temperature corrosion.

  Further, as in the drain outlet temperature adjusting system 80 shown in FIG. 4, the three-way valve 82 may be provided at the portion where the discharge pipe 31 branches into the first pipe 16 and the second pipe 22. The three-way valve 82 regulates drainage, steam, or both flowing in the first pipe 16 and the second pipe 22. As the three-way valve 82, a temperature-adjustable three-way valve can be used, and the opening / closing is controlled according to the temperature of the temperature sensor 26 of the seal pot 20. Similar to the above embodiment, the drain outlet adjusting system 80 can be applied to the boiler system 84 (FIG. 5). The boiler system 84 of FIG. 5 is the same as the boiler system 50 of FIG. 3 except that the drain outlet temperature adjusting system 10 is changed to the drain outlet temperature adjusting system 80 of FIG. 4.

  Drain and / or steam flowing through the discharge pipe 31 are made to flow to the first pipe 16 and the second pipe 22 by adjusting the opening / closing of the three-way valve 82. Specifically, if the temperature of the drain of the seal pot 20 is a predetermined temperature, drain, steam, or both of them are allowed to flow through the first pipe 16. Further, when the temperature of the drain of the seal pot 20 becomes lower than a predetermined temperature, the opening / closing of the three-way valve 82 is adjusted according to the lowered temperature, so that not only the first pipe 16 but also the second pipe 22 is drained and vaporized. , Or both. High-temperature drain, steam, or both of them flow from the second pipe 22 into the seal pot 20, and the temperature of the drain of the seal pot 20 can be raised to a predetermined temperature.

  The temperature of the drain of the seal pot 20 can be kept at a predetermined temperature, and the temperature when water is supplied from the cascade tank 56 to the boiler 52 can be kept high. It is not necessary to heat the boiler feed water, and the thermal efficiency of the boiler 52 is good. Even if the temperature of the exhaust gas supplied from the exhaust pipe 66 to the exhaust heat recovery boiler 62 is as low as 200 ° C., the temperature of the boiler feed water can be kept high, so that low-temperature corrosion countermeasures can be taken.

  In addition, the present invention can be carried out in a mode in which various improvements, modifications and changes are made based on the knowledge of those skilled in the art without departing from the spirit of the invention.

10, 80: Drain outlet temperature adjusting system 12: Drain cooler 14: Drain cooler inlet 16: First pipe 18: Drain cooler outlet 20: Seal pot 22: Second pipe 24: Water level adjusting valve 26: Temperature sensor 28: second pipe valve 30: drain cooler casing 31: discharge pipe 32: first pipe valve 34: drain cooler lower opening 36: seal pot drain 38: drain cooler opening 40: water level adjusting valve Inlet 42: outlet 50, 84 of the second piping: boiler system 52: boiler 54: condensate 56: cascade tanks 58a, 58b: heater 58c: tank heating 58d: tank cleaning heater 60: heat exchange section 62: exhaust Heat recovery boiler 64: Main engine 66: Exhaust pipe 68: Fuel tank 70: Fuel pipe 72: Heat exchange section 74: Excess steam adjusting valve 8 : The three-way valve

Claims (4)

A drain cooler that cools the drain, steam, or both;
A first pipe for supplying drain, steam, or both to the inlet of the drain cooler;
A seal pot at the outlet of the drain cooler,
A second pipe for supplying drain, steam, or both to the seal pot;
A temperature sensor for measuring the temperature of the drain of the seal pot,
A valve for adjusting the amount of drain, steam, or both of which the opening and closing are adjusted according to the temperature of the drain at the outlet of the drain cooler to be supplied to the first pipe and the second pipe,
A water level adjusting pipe for discharging drain from the seal pot,
An opening that is arranged at a position higher than the inlet of the water level adjusting pipe, and that connects the drain cooler and the seal pot,
Drain outlet temperature control system equipped with. The valve is a three-way valve,
The drain outlet temperature adjusting system according to claim 1, wherein when the temperature of the drain of the seal pot is lower than a predetermined temperature, the three-way valve is adjusted to increase the amount of drain, steam, or both supplied to the second pipe. The drain outlet temperature adjusting system according to claim 1, wherein the second pipe and the water level adjusting pipe are horizontally displaced from each other in the seal pot. A boiler system comprising the drain outlet temperature adjusting system according to any one of claims 1 to 3.

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