JP5348477B2 - Boiler and concentrated blow method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boiler capable of efficiently heat-exchanging between blow water and supplied water by concentrated blow. <P>SOLUTION: The boiler 1 includes a can 3, a steam-water separator 5, a steam taking-out line 6, a downcomer 7, a water supply line 11 for supplying water to the can 3, a concentrated blow line 15 for performing the concentrated blow, a heat exchanger 20 for heat-exchanging between the supplied water of the water supply line 11 and the blow water of the concentrated blow line 15, and a controller 30. The concentrated blow line 15 is installed with a concentrated blow valve 16 and a strainer 17. The concentrated blow valve 16 is an electric proportional control valve capable of continuously adjusting flow rate. The controller 30 controls a water supply pump 12 and the concentrated blow valve 16 so as to make the heat exchanger 20 continuously heat-exchange between the supplied water and the blow water by performing continuous water supply and continuous concentrated blow. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a boiler that is a heat source device that transfers heat obtained by burning fuel to water and converts it to water vapor or hot water, and more particularly to a concentrated blow of the boiler.

  In general, in a boiler, if the can water in the boiler is continuously heated at a high temperature for a long time, the concentration of the can water proceeds in proportion to the amount of steam generated, and the dryness of the steam decreases. When the dryness of the steam decreases, the boiler water is accompanied by the steam, and the boiler water contains various components. Vibration or abnormal noise may occur in the piping.

  For this reason, in a conventional boiler, a concentrating blow line provided with a concentrating blow valve is connected to the boiler can body, and the condensing blow is performed with the concentrating blow valve opened to discharge part of the boiler water. Concentration is prevented, and for example, such a boiler is disclosed in Patent Document 1 below.

  Further, in Patent Document 2 below, in a boiler that performs a concentration blow, in order to reduce wasteful waste heat due to the concentration blow, there is a gap between water supplied to the boiler can body and blow water discharged from the boiler can body. The structure which installed the heat exchanger for performing heat exchange in is disclosed.

JP 2008-2739 A JP 2002-22106 A

  By the way, in a conventional boiler, an electromagnetic valve is used as a concentration blow valve. Since the solenoid valve can only be in the fully open or fully closed state due to its structure, the amount of blow water discharged by the concentrate blow (concentrated blow amount) can be reduced by performing intermittent blow control to adjust the open time of the solenoid valve. I was adjusting.

  However, when concentration blow is intermittently performed, if water is supplied while the blow water is not discharged, heat exchange cannot be performed between the water supply and the blow water, and waste heat associated with the concentration blow is generated. Cannot be used effectively.

  This invention is made | formed in view of such a subject, and it aims at providing the boiler which can exchange heat efficiently between the blow water and water supply by concentration blow.

In order to solve the above problems, a boiler according to the present invention includes a can body, a water supply line for supplying water to the can body, a concentration blow line for discharging blow water from the can body, and the water supply line. A heat exchanger for exchanging heat between the feed water flowing through and the blow water flowing through the concentration blow line, the water feed line has a feed water pump that performs continuous water feed by inverter control , The concentration blow line has a proportional control valve capable of continuously adjusting the amount of blow water, and performs continuous concentration blow and continuous water supply , so that the water is supplied between the water supply and the blow water in the heat exchanger during water supply. And a controller for controlling the water supply pump and the proportional control valve so as to perform heat exchange continuously.

The concentration blow method according to the present invention includes a can body, a water supply line for supplying water to the can body, a concentration blow line for discharging blow water from the can body, and water supply flowing through the water supply line. And a heat exchanger for exchanging heat with blow water flowing through the concentration blow line. In the method for concentration blow in a boiler, continuous concentration blow is performed in the concentration blow line, and continuous water supply is performed in the water supply line. By performing the above, heat exchange is continuously performed between the water supply and the blow water in the heat exchanger during water supply.

  According to the present invention, it is possible to efficiently exchange heat between blow water and water supply by concentration blow.

FIG. 1 is a schematic diagram schematically showing the configuration of the boiler according to the present embodiment.

  Hereinafter, a boiler according to an embodiment of the present invention will be described with reference to the drawings. Drawing 1 is a mimetic diagram showing roughly the composition of boiler 1 concerning this embodiment. As shown in FIG. 1, the boiler 1 includes a can body 3, a steam / water separator 5, a steam discharge line 6, a downcomer pipe 7, a water supply line 11 for supplying water to the can body 3, and a concentration blow for performing concentration blow. The heat exchanger 20 and the controller 30 for exchanging heat between the water supplied from the line 15 and the water supply line 11 and the blow water from the concentration blow line 15 are provided.

  The can 3 is provided with a pressure sensor 4 for measuring the vapor pressure, and the detected value is sent to the controller 30. A water supply pump 12 is installed in the water supply line 11, and an inverter circuit 13 is connected to the water supply pump 12. The inverter circuit 13 is connected to the controller 30 and transmits the rotation speed of the water supply pump 12 to the controller 30 for inverter control. The feed water pump 12 is controlled by the controller 30 via the inverter circuit 13, and performs proportional (continuous) water supply by inverter control.

The concentration blow line 15 is provided with a concentration blow valve 16 and a strainer 17, and the concentration blow valve 16 is controlled by a controller 30. The concentration blow valve 16 according to the present embodiment is an electric proportional control valve capable of continuously adjusting the flow rate. Although the electric proportional control valve capable of adjusting the flow rate is likely to be clogged when the flow rate is small, in this embodiment, a strainer 17 is installed upstream of the concentration blow valve 16 that is an electric proportional control valve. Thus, the concentration blow valve 16 is prevented from being clogged. Also, prevention in order to prevent clogging of the blowdown valve 16, in addition to the installation of the strainer 17, the clogging of the blowdown valve 16 by performing the reverse cleaning is rotated 180 ° ball valve provided in the blowdown valve 16 You may do it.

  In this embodiment, the amount of blow water can be continuously adjusted by using the concentration blow valve 16 having a continuously variable flow rate as the blow valve in the concentration blow line 15. Therefore, when the amount of blow water is intermittently adjusted by controlling the opening time of the solenoid valve as in the conventional case, the blow water may not flow through the heat exchanger 20, whereas in this embodiment, continuous concentration is performed. The blow water can be continuously flowed in the heat exchanger 20 by the blow.

  As described above, in this embodiment, continuous water supply is performed by inverter control, and continuous heat exchange can be performed between the blow water and the water supply together with the continuous concentration blow. The wasteful heat that accompanies it can be greatly reduced.

  Subsequently, the opening degree adjustment of the concentration blow valve 16 by the controller 30 in the present embodiment will be described in detail. The opening degree X (%) of the concentration blow valve 16 is determined from the concentration blow rate A (%) (ratio between the blow amount and the water supply amount) according to the function setting and the pressure correction coefficient due to the steam pressure P (MPa). For example, it is determined by the following formula.

Accordingly, when the concentration blow rate is A = 20% and the steam pressure P = 0.686 MPa (7.0 kgf / cm ² ), the pressure correction coefficient is 1, and the opening X of the blow valve 16 is 100%. . When the steam pressure P ≦ 0, P = 0.01, and the upper limit of the opening degree X is 100%. Further, the vapor pressure P is measured periodically (for example, every minute ) .

  Of course, another calculation formula may be used for the opening degree X of the concentration blow valve 16, for example, a formula using the high combustion conversion time or the feed water temperature as a parameter may be used. In the present embodiment, when the continuous water supply in the water supply line 11 is stopped, the controller 30 controls the concentration blow valve 16 to be closed in order to prevent useless waste heat due to the concentration blow.

  Thus, in this embodiment, by adopting an electric proportional control valve that can continuously adjust the flow rate as a concentration blow valve, it becomes possible to discharge continuous blow water at a flow rate according to the blow rate, Heat exchange can be efficiently performed between continuously supplied water and blow water. In particular, in a region where the amount of concentration blow is small, heat loss can be greatly suppressed as compared with conventional intermittent concentration blow.

  Further, according to the present embodiment, by continuously performing the concentration blow, it is possible to suppress the fluctuation in the electrical conductivity of the boiler water in the can as compared with the case of the conventional intermittent concentration blow, and to stabilize the boiler. The maintainability can be improved.

  Then, the test result which compared the heat recovery amount in the heat exchanger by the continuous concentration blow which concerns on this embodiment, and the heat recovery amount in the heat exchanger by the conventional intermittent concentration blow is demonstrated. In the above embodiment, the combination of continuous concentrating blow and continuous water supply with the best heat recovery rate has been described. However, even if the water supply is intermittent water supply, the amount of heat recovery can be increased by adopting continuous concentrating blow. Since it can improve, the test result at the time of combining continuous concentration blow and intermittent water supply was also shown as a modification of this embodiment.

  Table 1 below shows this embodiment (continuous water supply / continuous concentration blow), a modification of this embodiment (intermittent water supply / continuous concentration blow), comparative example 1 (continuous water supply / intermittent concentration blow) and comparative example 2 (intermittent water supply). The test result of the heat recovery amount in the heat exchanger of (/ intermittent concentration blow) is shown. Table 1 shows the heat recovery amount when the concentration blow rate is 5%, 10%, 15%, and 20%, and the heat recovery amount at each concentration blow rate of Comparative Example 2 is 1. In this case, the heat recovery amount is shown.

  The intermittent concentration blow in this test is that the blow valve is always open when the concentration blow rate is 20%, the blow valve is opened for 7.5 minutes and closed for 2.5 minutes when the concentration blow rate is 15%, and 10%. When the blow valve is open for 5 minutes and closed for 5 minutes, and 5%, the blow valve is opened for 2.5 minutes and closed for 7.5 minutes to perform intermittent concentration blow.

  As shown in Table 1, this embodiment greatly improves the amount of heat recovery compared to Comparative Example 2 at all concentrated blow rates. Further, comparing this embodiment with Comparative Example 1, when the concentration blow rate is 20%, the heat recovery amount is almost the same because the solenoid valve is always open in Comparative Example 1 as well. In the case of other concentrated blow rates, the heat recovery amount of the present embodiment is higher and the heat recovery rate is greatly improved.

  Moreover, since the modified example of this embodiment is intermittent water supply, compared with Comparative Example 1 in which continuous water supply and intermittent concentration blow are performed, the amount of heat recovered is 15% and 20% in the concentration blow rate with a short closing time of the solenoid valve. However, when the concentration blow rate is 5% and 10%, which increases the closing time of the solenoid valve, the heat recovery rate is much higher and the heat recovery rate is greatly improved compared to Comparative Example 2. doing.

  Therefore, according to this test result, according to the embodiment of the present invention in which a continuous concentration blow is performed using a proportional control valve capable of continuously adjusting the flow rate as a concentration blow valve, compared to a case where a conventional intermittent concentration blow is performed, It is supported that the heat recovery rate in the heat exchanger can be greatly improved.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible within the range which does not deviate from the main point of this invention. For example, in the above embodiment, an electric proportional control valve is used as a valve for continuously adjusting the amount of blow water. However, any other proportional control valve can be used as long as it can continuously adjust the flow rate flowing through the valve. The valve can be used.

DESCRIPTION OF SYMBOLS 1 Boiler 3 Can body 4 Pressure sensor 5 Air-water separator 6 Steam extraction line 7 Precipitation pipe 11 Water supply line 12 Water supply pump 13 Inverter circuit 15 Concentration blow line 16 Concentration blow valve 17 Strainer 20 Heat exchanger 30 Controller

Claims (2)

Between a can body, a water supply line for supplying water to the can body, a concentration blow line for discharging blow water from the can body, a water supply flowing through the water supply line, and a blow water flowing through the concentration blow line In a boiler comprising a heat exchanger for performing heat exchange at
The water supply line has a water supply pump that performs continuous water supply by inverter control ,
The concentration blow line has a proportional control valve capable of continuously adjusting the amount of blow water,
By performing continuous concentration blow and continuous water supply , the water supply pump and the proportional control valve are controlled so that heat is continuously exchanged between the water supply and the blow water in the heat exchanger during water supply. A boiler comprising a controller. Between a can body, a water supply line for supplying water to the can body, a concentration blow line for discharging blow water from the can body, a water supply flowing through the water supply line, and a blow water flowing through the concentration blow line And a heat exchanger for performing heat exchange with a concentration blow method in a boiler comprising:
In addition to performing continuous concentration blow in the concentration blow line and continuous water supply in the water supply line, heat exchange is continuously performed between the water supply and the blow water in the heat exchanger during water supply. Concentrated blow method characterized by.

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