JP5360560B2 - boiler - Google Patents

Abstract

A boiler capable of performing a concentration blow with a proper blow amount at all times even if the boiler has a large variation in concentration blow amount as in the case of boilers with large turn down ratio.  The boiler comprises a can body, a blower, a duct, an exhaust tube, a separator, a concentration blow line, and a controller.  The concentration blow line comprises a plurality of branch lines which have respective blow solenoid valves and which are installed parallel to each other.  The controller selectively opens and closes the plurality of solenoid valves for controlling the flow in the concentration blow line by selectively using the branch lines.

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.

  In addition, as in the boiler disclosed in Patent Document 1 below, the combustion amount is controlled in a plurality of combustion states such as high combustion, low combustion, and stop. In such a case, the amount of steam supply also changes according to the combustion state, so it is necessary to adjust the amount of concentrated blow according to that, and in Patent Document 1, the opening time of the concentration blow valve is adjusted according to the state of combustion. The amount of concentrated blow is adjusted.

JP 2008-2739 A

  By the way, in the case of a boiler with a large turndown ratio between high combustion and low combustion, the difference in the desired amount of concentrated blow in each combustion mode also increases. It becomes difficult to realize the optimum amount of concentration blow.

  For example, if the tube diameter of the concentrate blow line is set according to the concentrate blow amount in the high combustion, the instantaneous blow amount becomes larger than the evaporation amount at the time of the concentrate blow in the low combustion, and the feed water is discharged out of the can instead of the concentrate. Or the lower header temperature decreases and water pipe overheating occurs.

  Also, the difference in the desired concentration blow rate increases depending on the concentration blow rate (the ratio of the blow water amount to the water supply amount), and the optimum concentration blow amount for all concentration blow rates can be achieved simply by adjusting the opening time of the concentration blow valve. Difficult to do.

  The present invention has been made in view of such a problem, and it is possible to always perform concentration blow with an appropriate blow amount even in a boiler having a large fluctuation range of the concentrate blow amount, such as a boiler with a large turndown ratio. The aim is to provide a possible boiler.

In order to solve the above problems, a boiler according to the present invention includes a can body and a concentrated blow line for discharging blow water from the can body, wherein the concentrated blow lines each have a blow valve. And having a plurality of branch lines installed in parallel, and selectively using the plurality of branch lines to adjust the instantaneous blow amount of the concentrated blow water flowing through the concentrated blow line to a flow rate corresponding to the combustion stage In order to achieve this, a controller for selectively opening and closing the plurality of blow valves according to the combustion stage is provided.

  According to the present invention, even if the boiler has a large fluctuation range of the concentrated blow amount, the concentrated blow can be performed with an appropriate blow amount.

FIG. 1 is a schematic diagram schematically showing the configuration of a boiler according to an embodiment of the present invention. FIG. 2 is a view showing an open / close control mode of each blow solenoid valve during concentration blow according to the embodiment of the present invention. FIG. 3 is a view showing an open / close control mode of each blow solenoid valve during concentration blow according to a modification of the present invention.

  Hereinafter, a boiler according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram schematically showing the configuration of the boiler according to the present embodiment. As shown in the figure, the boiler 1 includes a can body 2, a blower 3, a duct 4, an exhaust pipe 5, a separator 6, a concentration blow line 10, and a controller 30.

  In the boiler 1, combustion air is supplied from the blower 3, and the fuel gas mixed in the duct 4 and the combustion air are burned in the can body 2 to connect the upper header and the lower header in the can body 2. Heat the water tube. The exhaust gas after combustion is discharged from the exhaust cylinder 5 to the outside. The separator 6 is connected to the upper header by the steam extraction line 7 and is connected to the lower header by the downcomer 8, and the steam is taken out from the separator 6 by opening the main steam valve 9.

  The concentrated blow line 10 is connected to the downcomer 8, and concentrated water is discharged to the outside through the concentrated blow line 10 during the concentrated blow. The concentration blow line 10 includes a first branch line 11, a second branch line 15, and a third branch line 19 that are branched in parallel. In the first branch line 11, a first blow electromagnetic valve 12 and a first orifice 13 are installed, in the second branch line 15, a second blow electromagnetic valve 16 is installed, and in the third branch line 19, A third blow solenoid valve 20 is installed.

  Here, the piping size constituting the first to third branch lines 11, 15, 19 is 10A, and the first orifice of the first branch line 11 is configured to reduce the size to 5A. The controller 30 is connected to the main steam valve 9, the first blow electromagnetic valve 12, the second blow electromagnetic valve 16, and the third electromagnetic blow valve 20, and controls the opening and closing of these valves. In addition, the turndown ratio of the boiler 1 which concerns on this embodiment is 1: 5.

  The configuration of the boiler 1 has been described above. Next, the control mode of the concentration blow in the boiler 1 will be described with reference to FIG. FIG. 2 is a view showing an open / close control mode of each blow solenoid valve during the concentration blow according to the present embodiment. Here, the boiler 1 according to the present embodiment controls the combustion amount at three positions of high combustion, low combustion, and stop, and increases or decreases the opening time of the blow solenoid valve per cycle of a predetermined period. Thus, the concentrated blow amount is adjusted so as to be a preset desired concentrated blow rate (ratio of the blow water amount to the water supply amount).

  At the time of high combustion with a large amount of steam supply, the controller 30 controls the opening and closing of all of the first to third blow solenoid valves 12, 16, and 20, and all the lines of the first to third branch lines 11, 15, and 19 are controlled. The blow water is controlled to be discharged from the first and third blow solenoid valves 12, 16, and 20 so that the concentration blow rate is set by increasing or decreasing the open time.

  Further, at the time of low combustion with a small amount of steam supply, the controller 30 controls the opening / closing of only the first blow solenoid valve 12 and closes the second and third blow solenoid valves 16, 20, so that the first branch line 11. The blow water is controlled to be discharged only from the exhaust gas, and the concentration blow rate is set by increasing or decreasing the opening time of the first blow solenoid valve 12.

  As described above, if the plurality of blow solenoid valves 12, 16, and 20 installed in parallel to the concentration blow line 10 are selectively controlled to be opened and closed at high combustion and low combustion, the branch line 11 is supplied at the time of concentration blow. , 15, 19 can be selectively used to adjust the instantaneous blow amount of the concentrated blow water flowing through the concentrate blow line 10 to a flow rate suitable for each combustion mode, so that the boiler has a large turndown ratio. Also, it is possible to perform an appropriate concentration blow in each combustion mode. Note that the term “selectively” in this specification includes a case where all options are selected.

  In this embodiment, the ratio of the instantaneous blow amount at the time of low combustion and the instantaneous blow amount at the time of high combustion is about 1: 6, and even if the turndown ratio of the boiler 1 is as large as 1: 5, Concentrated blow water can be discharged at a flow rate suitable for the combustion mode.

  Subsequently, a modification of the control mode of the concentration blow will be described with reference to FIG. FIG. 3 is a diagram showing an open / close control mode of each blow solenoid valve during the concentration blow according to this modification. In the above embodiment, the branch line that is selectively used during the concentration blow is determined according to the combustion mode. However, in this modification, the branch line is selectively used during the concentration blow according to a preset concentration blow rate. Determine the branch line.

  For example, when the concentration blow rate is 10% or less, only the first branch line 11 is used, and when the concentration blow rate is 10 to 15%, only the first branch line 11 and the second branch line 15 are used. If it is used and the concentration blow rate is 15% or more, the controller 30 controls to discharge the blow water using all of the first to third branch lines 11, 15 and 19.

  Specifically, when the concentration blow rate is 10% or less, the controller 30 keeps the second and third blow solenoid valves 16 and 20 closed, and changes the desired time by increasing or decreasing the open time of the first blow solenoid valve. It controls so that it may become the concentration blow rate of. Further, when the concentration blow rate is 10 to 15%, the controller 30 keeps the third blow solenoid valve 20 closed, and the desired value is obtained by increasing or decreasing the open time of the first and second blow solenoid valves 12 and 16. Control to achieve a concentration blow rate. When the concentration blow rate is 15% or more, the controller 30 controls the first to third blow solenoid valves 12, 16, and 20 to increase or decrease the open time of the first to third blow solenoid valves 12, 16, and 20 to achieve a desired concentration blow rate.

  In this modification, the branch lines 11, 15, and 19 are selectively used during the concentration blow according to the concentration blow rate, so that the instantaneous blow amount of the concentration blow line 10 is set to an appropriate flow rate according to the concentration blow rate. Since it can be adjusted, even if it is a boiler with a large capacity and the amount of blown water varies greatly depending on the concentration blow rate, it is possible to perform an appropriate concentration blow according to the concentration blow rate.

  As described above, the present embodiment has been described in detail including modifications, but according to the present embodiment, the flow at the time of the concentration blow can be adjusted by selectively using a plurality of branch lines. Even in a boiler with a large fluctuation range, an appropriate amount of concentration blow can always be performed. Moreover, if the flow rate at the time of the concentration blow can be adjusted, it is possible to adjust the concentration blow continuously, so that efficient heat exchange can be performed between the concentration blow water and the feed water.

  The embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in this embodiment, three branch lines are installed in parallel in the concentration blow line, but the number of branch lines installed in parallel may be two or four or more as long as it is plural.

  In the present embodiment, the blow valve installed in the concentration blow line is an electromagnetic blow valve. However, a proportional control valve such as a motor valve capable of continuously adjusting the flow rate may be used as the blow valve.

DESCRIPTION OF SYMBOLS 1 Boiler 2 Can body 6 Separator 10 Concentration blow line 11 1st branch line 12 1st blow solenoid valve 15 2nd branch line 16 2nd blow solenoid valve 19 3rd branch line 20 3rd blow solenoid valve 30 Controller

Claims (3)

In a boiler comprising a can body and a concentrated blow line for discharging blow water from the can body,
The concentration blow line has a plurality of branch lines installed in parallel, each having a blow valve,
In order to adjust the instantaneous blow amount of the concentrated blow water flowing through the concentrated blow line selectively to the flow rate corresponding to the combustion stage by selectively using the plurality of branch lines, the plurality of blow valves are set according to the combustion stage. A boiler comprising a controller that selectively controls opening and closing. The concentration blow line is a first branch line installed in parallel, a first branch line installed with a first blow valve, a second branch line installed with a second blow valve, and a third branch line installed with a third blow valve. With
The controller controls opening / closing of all of the first blow valve, the second blow valve and the third blow valve during high combustion, and controls opening / closing of only the first blow valve during low combustion. The boiler according to claim 1, wherein the second blow valve and the third blow valve are controlled to be closed. The boiler according to claim 1, wherein the plurality of branch lines have the same tube diameter.

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