JP5829640B2 - Ship boiler feed water temperature control system - Google Patents

Description

  The present invention relates to a feed water temperature control system for a boiler mounted on a ship as a steam source.

  C heavy oil is mainly used as a fuel oil for a large diesel engine mounted on a ship as a main engine that is a propulsion drive source of the ship. Heavy oil used as fuel oil has a higher boiling point than gasoline and light oil and is thicker, and the fuel oil supplied from the fuel tank to the engine, that is, the main engine through the fuel supply pipe, is supplied to the main engine until The viscosity is lowered by heating in advance.

  In order to heat the fuel oil, the ship is equipped with a fuel heater. The fuel heater is a heat exchange device using steam obtained by heating fresh water with a boiler as a heating source, and the boiler burns heavy oil with a burner to generate steam. The steam supplied to the fuel heater is condensed after heating the fuel oil, becomes high-temperature drain, cooled by the drain cooler, returned to the cascade tank, and circulated and supplied to the boiler. In this way, the ship is equipped with a fuel heating device for heating the fuel oil supplied to the main engine, and the fuel heating device constitutes a boiler thermal cycle provided with a boiler for generating steam. doing.

  In order to cool the water jacket and the air cooler of the main engine, as described in Patent Document 1, a fresh water circulation cooling system is mounted on the ship.

JP 2011-137438 A

  As described above, in a ship having a large diesel engine as a main engine, since the fuel oil is used as a boiler fuel in order to heat the fuel oil supplied to the main engine, the main engine including the boiler heat cycle is included. In order to reduce the fuel consumption of the boiler, it is necessary to reduce the fuel consumption of the boiler thermal cycle provided with the boiler. Until now, various studies have been made to reduce the fuel consumption of the main engine, but no consideration has been given to reducing the fuel consumption of the boiler heat cycle. Therefore, various studies have been made to improve the fuel efficiency of the boiler heat cycle for heating the fuel oil.

  The steam supplied to the fuel heater is condensed after being used for heating the fuel oil, becomes high-temperature drain, cooled to 30 to 40 ° C. by the drain cooler, and supplied to the cascade tank. The drain cooler is a heat exchange device that uses seawater or the like as cooling water. In conventional boilers, steam is generated by heating the feed water at 30 to 40 ° C. However, the drain cooler cannot control the temperature of the condensate, and the steam generated by the temperature of the condensate and the boiler. The temperature difference from the temperature is large. For this reason, there was a limit to fuel reduction in a boiler thermal cycle having a boiler.

  An object of the present invention is to improve the thermal efficiency of a boiler thermal cycle for heating fuel oil supplied to the main engine, and to improve the fuel efficiency of the main engine including this thermal cycle.

This ship boiler feed water temperature control system is a ship boiler feed water temperature control system for heating fuel oil supplied to a main engine that drives a propeller for ship propulsion, and the main engine is connected to a fuel supply pipe from a fuel tank. A boiler that supplies steam to a fuel heater that heats the fuel oil supplied to the boiler, a cascade tank that stores condensate supplied to the boiler, and a high-temperature drain discharge pipe that discharges high-temperature drain from the fuel heater A drain cooler connected to the main pipe for cooling the high-temperature drain, a low-temperature drain supply pipe connected between the drain cooler and the cascade tank and guiding the drain cooled by the drain cooler to the cascade tank, and the fuel heater A bypass pipe for directly guiding the high-temperature drain discharged from the cascade tank to the cascade tank; Possess a condensate flow rate control device for controlling the ratio between the high temperature drain and cold drain guided to the cascade tank by the the scan tube cold drain supply tube, wherein the condensate flow rate adjusting device, the fuel heater An inlet connected to the high-temperature drain outlet; a first outlet connected to the main pipe; and a second outlet connected to the bypass pipe; the inlet and the first It is a three-way valve that changes the opening degree of communication with the outlet and the opening degree of communication between the inlet and the second outlet. The ship boiler feed water temperature control system is a ship boiler feed water temperature control system for heating fuel oil supplied to a main engine that drives a propeller for ship propulsion. A boiler that supplies steam to a fuel heater that heats fuel oil supplied to the main engine, a cascade tank that stores condensate supplied to the boiler, and a high-temperature drain discharge pipe that discharges high-temperature drain from the fuel heater A drain cooler for cooling the high-temperature drain connected to a main pipe communicating with the low-temperature drain supply pipe connected between the drain cooler and the cascade tank and guiding the drain cooled by the drain cooler to the cascade tank; A bypass pipe for directly guiding the high-temperature drain discharged from the fuel heater to the cascade tank; Possess a condensate flow rate control device for controlling the ratio between the high temperature drain and cold drain guided to the cascade tank by the bypass pipe cold drain supply tube, wherein the condensate flow rate adjusting device, and the main pipe, It is a two-way valve that is provided on one side of the bypass pipe and changes the flow rate of the high-temperature drain flowing through the one side.

  The fuel heater that heats the fuel oil supplied to the main engine is supplied with steam generated by heating the condensate contained in the cascade tank with a boiler. The high-temperature drain discharged from the fuel heater is branched into a high-temperature drain supplied to the drain cooler and a high-temperature drain returned directly to the cascade tank in order to keep the water temperature in the cascade tank at a high temperature. As described above, the condensate in the cascade tank is injected with the high-temperature drain discharged from the fuel heater and the drain cooled by the drain cooler, and controlled so as to keep the water temperature in the cascade tank at a high temperature. Thereby, the thermal efficiency of the boiler cycle which heats condensate and generates steam can be raised.

  Furthermore, by increasing the temperature of the condensate supplied to the boiler, the amount of dissolved oxygen contained in the condensate can be reduced and the internal corrosion of the boiler can be reduced, thus improving the durability of the boiler. be able to.

It is the boiler cycle whole figure including the boiler feed water temperature control system of a ship. It is the whole boiler cycle including the boiler feed water temperature control system of the ship which is a modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, a ship main body 12 for driving a ship propeller 11 is mounted on the hull of the ship, and the main machine 12 is constituted by a diesel engine using heavy oil as fuel oil. A fuel tank 13 for storing fuel oil is connected to the main engine 12 by a fuel supply pipe 14, and the fuel oil is supplied to the main engine 12 through the fuel supply pipe 14.

  In order to heat the fuel oil supplied from the fuel tank 13 to the main engine 12, a fuel heater 15 is provided in the ship. The fuel heater 15 has a heater main body 17 in which a heat exchanging portion 16 provided in the fuel supply pipe 14 is incorporated. The fuel heater 15 flows through the fuel supply pipe 14 by the steam supplied into the heater main body 17 and is supplied to the main machine 12. The fuel to be heated is heated. A boiler 18 that generates steam is mounted on a ship, and the boiler 18 has a burner that generates steam by burning fuel oil and heating condensate. In order to supply the generated steam to the fuel heater 15, a steam supply pipe 21 is connected between the steam discharge port 18 a of the boiler 18 and the steam inlet 15 a of the fuel heater 15.

  A cascade tank 22 for storing the condensate supplied to the boiler 18 is mounted on the ship, and in order to supply the condensate W in the cascade tank 22 to the boiler 18, a condensate discharge port 22a of the cascade tank 22 and A condensate discharge pipe 23 is connected to the condensate inlet 18 b of the boiler 18. Condensate W in the cascade tank 22 is supplied to the boiler 18 by a water supply pump 24 provided in the condensate discharge pipe 23.

  In order to use the exhaust gas of the main engine 12 as a heat source applied to the boiler 18, an exhaust heat recovery boiler 26 to which an exhaust pipe 25 is supplied is provided in the ship. The exhaust heat recovery boiler 26 has a heat exchanging portion 27 through which the condensate in the boiler 18 circulates. The heat exchanging portion 27 is incorporated in the exhaust heat recovery boiler main body 28, and the exhaust heat recovery boiler main body 28. The condensate flowing in the heat exchanging unit 27 is heated by the exhaust gas supplied inside. The boiler 18 can generate steam by either or both of the thermal energy of the combustion gas of the burner and the thermal energy of the exhaust gas using the exhaust gas of the main engine 12 when the ship is sailing. . On the other hand, when the operation of the main engine 12 is stopped, such as when the ship is anchored at the port and preparing for departure, the exhaust gas cannot be used. Will be generated.

  A high temperature drain discharge pipe 31 is connected to the high temperature drain discharge port 15 b of the fuel heater 15, and a low temperature drain supply pipe 32 is provided between the high temperature drain discharge pipe 31 and the low temperature drain injection port 22 b of the cascade tank 22. It is connected. The low-temperature drain supply pipe 32 is provided with a drain cooler 33 for cooling the high-temperature drain discharged from the high-temperature drain discharge port 15b. The high temperature drain is cooled by the drain cooler 33 and supplied to the cascade tank 22.

  A bypass pipe 34 is connected to the high-temperature drain discharge pipe 31 to bypass the high-temperature drain discharged from the fuel heater 15 and directly guide it to the cascade tank 22 without passing through the drain cooler 33. The downstream end of the pipe 31 is branched into a main pipe 42 and a bypass pipe 34. This bypass pipe 34 is connected to the high temperature drain inlet 22 c of the cascade tank 22. Thus, between the fuel heater 15 and the cascade tank 22, the high-temperature drain discharged from the fuel heater 15 is cooled by the drain cooler 33 and supplied to the cascade tank 22, and without being supplied to the drain cooler 33. A bypass pipe 34 that bypasses and returns the high-temperature drain to the cascade tank 22 is connected via a high-temperature drain discharge pipe 31.

  The high-temperature drain inlet 22c and the low-temperature drain inlet 22b are provided below the liquid level of the condensate W in the cascade tank 22, and when injected into the cascade tank 22, the temperature of the condensate is increased by stirring. In addition, the temperature in the cascade tank 22 is adjusted by stirring to a uniform temperature as a whole.

  A three-way valve 35 is provided as a condensate flow rate adjusting device at a branch portion between the main pipe 42 and the bypass pipe 34, and the three-way valve 35 is connected to a high-temperature drain discharge port 15 b through a high-temperature drain discharge pipe 31. The inlet 35a has a first outlet 35b to which the main pipe 42 is connected, and a second outlet 35c to which the bypass pipe 34 is connected. By operating the valve shaft of the three-way valve 35, the three-way valve 35 has a communication opening degree between the high-temperature drain inlet 35a and the first outlet 35b, and between the high-temperature drain inlet 35a and the second outlet 35c. Change the communication opening. By changing the respective communication openings, the ratio of the high temperature drain guided to the drain cooler 33 by the main pipe 42 and the high temperature drain guided directly to the cascade tank 22 by the bypass pipe 34 is controlled. The temperature is controlled.

  The cascade tank 22 is provided with a temperature sensor 36 for detecting the temperature of the condensate W inside, and a detection signal of the temperature sensor 36 is sent to a controller 37 as temperature control means. The controller 37 sends a drive signal to a valve actuator 38 that operates the valve shaft of the three-way valve 35, and automatically controls the ratio of the high-temperature drain guided to the drain cooler 33 and the high-temperature drain guided directly to the cascade tank 22, The temperature of the condensate W is adjusted to the set temperature. The controller 37 includes a memory in which calculation data is stored, and a calculation unit that calculates a signal to be sent to the valve actuator 38. The memory includes a set temperature of the condensate W and two outlets 35b and 35c. Is stored, and the opening ratios of the outlets 35b and 35c are calculated by the calculation unit based on the detection signal of the temperature sensor 36.

  The condensate discharge pipe 23 includes a sensor unit 39 in which a temperature sensor for detecting the temperature of the condensate flowing through the condensate discharge pipe 23 and an alarm sensor for issuing an alarm when the detected temperature exceeds a set value are incorporated. Is provided. As described above, the temperature in the cascade tank 22 is detected by the temperature sensor 36 and the flow rate of the high-temperature drain is controlled, but the high-temperature drain is determined by the temperature in the condensate discharge pipe 23 detected by the sensor unit 39. The flow rate may be controlled.

  As shown in FIG. 1, since the opening ratios of the two outlets 35b and 35c are adjusted using the three-way valve 35, an open / close valve, that is, a two-way valve is provided in the main pipe 42 and the bypass pipe 34, respectively. Compared to the configuration, the temperature of the condensate can be controlled by one three-way valve 35. However, two two-way valves may be provided. In that case, the main pipe 42 and the bypass pipe 34 may be directly connected to the high-temperature drain discharge port 15b of the fuel heater 15, respectively.

  FIG. 2 is an overall view of a boiler cycle including a ship boiler feed water temperature control system which is a modified example. 2, members that are the same as those in the overall view of the boiler cycle shown in FIG.

  In this fuel oil heating apparatus, the main pipe 42 is directly connected to the high-temperature drain discharge pipe 31, and the bypass pipe 34 is an on-off valve, that is, a two-way valve for changing the flow rate of the high-temperature drain flowing through the flow path. 41 is provided as a condensate flow rate adjusting device. The two-way valve 41 has a high-temperature drain inlet 41 a connected to the high-temperature drain outlet 15 b via the high-temperature drain discharge pipe 31 and an outlet 41 b to which the bypass pipe 34 is connected. By the drive signal sent from the controller 37, the two-way valve 41 automatically controls the ratio of the high temperature drain guided to the drain cooler 33 and the high temperature drain guided directly to the cascade tank 22. As shown in FIG. 2, in the embodiment using one two-way valve 41, the two-way valve 41 may be provided in the main pipe 42 instead of the bypass pipe 34. And provided on one side of the main pipe 42.

  As shown in FIGS. 1 and 2, the boiler 18 uses the heat energy obtained by burning the fuel oil with the burner, the heat energy of the exhaust gas of the main engine 12, and the heat energy as the heat energy. Water W is heated and steam of about 170 ° C. is generated. The generated steam is supplied to the fuel heater 15, and the fuel oil supplied from the fuel tank 13 to the main engine 12 through the fuel supply pipe 14 is heated to adjust the viscosity of the fuel oil. The steam that has heated the fuel oil is condensed and becomes a high-temperature drain having a temperature of about 100 ° C., and flows out from the high-temperature drain discharge port 15 b to the high-temperature drain discharge pipe 31. The high temperature drain flowing out from the high temperature drain outlet 15b is branched into a high temperature drain guided to the drain cooler 33 and a high temperature drain guided directly to the cascade tank 22 by the bypass pipe.

  The high temperature drain guided to the drain cooler 33 is cooled to 30 to 40 ° C. by the drain cooler 33 and returned to the cascade tank 22, and the high temperature drain guided to the bypass pipe 34 is directly supplied to the cascade tank 22. As described above, the boiler feed water temperature control system shown in the figure is configured such that the high-temperature drain discharged from the fuel heater 15 is cooled by the drain cooler 33 and returned to the cascade tank 22, and the bypass flow returns to the cascade tank 22 while maintaining the high-temperature drain. The condensate W in the cascade tank 22 has a drain cooled to 30 to 40 ° C. by the drain cooler 33 and a high-temperature drain of about 100 ° C. from the bypass pipe 34 as it is. The condensate W injected into the cascade tank 22 is kept at a high temperature. Therefore, the condensate supplied from the cascade tank 22 to the boiler 18 by the feed water pump 24 has a higher temperature than the condensate cooled by the conventional drain cooler 33. Thereby, compared with the case where all the high-temperature drain discharged | emitted from the fuel heater 15 is cooled with the drain cooler 33, the thermal energy for generating a vapor | steam with the boiler 18 can be reduced, and the thermal efficiency of a boiler cycle can be improved. it can.

  Furthermore, since the temperature of the condensate accommodated in the cascade tank 22 for supplying the boiler 18, that is, the feed water temperature, can be kept at a high temperature, the amount of oxygen dissolved in the condensate, that is, the amount of dissolved oxygen can be reduced. . If the amount of dissolved oxygen in the condensate can be reduced, the internal corrosion of the boiler 18 can be reduced, so that the durability of the boiler 18 can be increased.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, although the illustrated boiler heat cycle has one fuel heater 15, it may be a boiler heat cycle having a plurality of fuel heaters. In the boiler heat cycle, fresh water is circulated, but the hot water in the cascade tank 22 may be supplied from the cascade tank 22 as another heat source such as a heat source for the lubricating oil of the main engine 12. .

DESCRIPTION OF SYMBOLS 11 Propeller 12 Main machine 13 Fuel tank 14 Fuel supply pipe 15 Fuel heater 15a Steam inlet 15b High temperature drain outlet 16 Heat exchange part 17 Heater body 18 Boiler 18a Steam outlet 18b Condensate inlet 21 Steam supply pipe 22 Cascade tank 22a Condensate Discharge port 22b Low temperature drain injection port 22c High temperature drain injection port 23 Condensate discharge tube 24 Water supply pump 25 Exhaust tube 26 Exhaust heat recovery boiler 27 Heat exchange unit 28 Exhaust heat recovery boiler body 31 High temperature drain discharge tube 32 Low temperature drain supply tube 33 Drain cooler 34 Bypass pipe 35 Three-way valve 35a High-temperature drain inlet 35b First outlet 35c Second outlet 36 Temperature sensor 37 Controller 38 Valve actuator 39 Sensor unit 41 Two-way valve 42 Main pipe

Claims (3)

A boiler boiler feed water temperature control system for heating fuel oil supplied to a main engine that drives a propeller for ship propulsion,
A boiler that supplies steam to a fuel heater that heats fuel oil supplied to the main engine from a fuel tank through a fuel supply pipe;
A cascade tank containing condensate supplied to the boiler;
A drain cooler connected to a main pipe communicating with a high temperature drain discharge pipe for discharging high temperature drain from the fuel heater and cooling the high temperature drain;
A low-temperature drain supply pipe connected between the drain cooler and the cascade tank and guiding the drain cooled by the drain cooler to the cascade tank;
A bypass pipe for directly guiding the high-temperature drain discharged from the fuel heater to the cascade tank;
Have a, a condensate flow rate control device for controlling the ratio between the high temperature drain and cold drain guided to the cascade tank by the low-temperature drain supply pipe and the bypass pipe,
The condensate flow rate adjusting device includes an inlet connected to the high-temperature drain outlet of the fuel heater, a first outlet connected to the main pipe, and a second outlet connected to the bypass pipe. And a boiler feed water temperature control for a ship, which is a three-way valve that changes a communication opening degree between the inlet and the first outlet and a communication opening degree between the inlet and the second outlet. system. A boiler boiler feed water temperature control system for heating fuel oil supplied to a main engine that drives a propeller for ship propulsion,
A boiler that supplies steam to a fuel heater that heats fuel oil supplied to the main engine from a fuel tank through a fuel supply pipe;
A cascade tank containing condensate supplied to the boiler;
A drain cooler connected to a main pipe communicating with a high temperature drain discharge pipe for discharging high temperature drain from the fuel heater and cooling the high temperature drain;
A low-temperature drain supply pipe connected between the drain cooler and the cascade tank and guiding the drain cooled by the drain cooler to the cascade tank;
A bypass pipe for directly guiding the high-temperature drain discharged from the fuel heater to the cascade tank;
Have a, a condensate flow rate control device for controlling the ratio between the high temperature drain and cold drain guided to the cascade tank by the low-temperature drain supply pipe and the bypass pipe,
The boiler feed water temperature control system for a ship, wherein the condensate flow rate adjusting device is a two-way valve that is provided on one of the main pipe and the bypass pipe and changes the flow rate of the high-temperature drain flowing through one of the main pipe and the bypass pipe . 3. The boiler feed water temperature control system according to claim 1 , wherein a temperature sensor that detects a temperature of condensate in the cascade tank and a high temperature that is supplied to the drain cooler based on a detection signal from the temperature sensor. A boiler boiler feed water temperature control system, comprising: a temperature control device that controls a temperature of condensate in the cascade tank by changing a ratio of the drain and the high-temperature drain directly supplied to the cascade tank.

Images