JP2006145158A - Intake air temperature control method and device for indoor boiler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake air temperature control method and device for an indoor boiler capable of preventing unnecessary rising of a temperature of intake air sucked in by a blower and supplied to a boiler body in the summer, eliminating a need for a load limit in the boiler body accompanying constraints in temperatures of various apparatuses, and capable of reducing running costs by suppressing increase of auxiliary machine power due to volume increase of exhaust gas. <P>SOLUTION: A hot air damper 7 controlling a hot air flow rate is provided in an intake line 6 midway part, a cold air line 8 taking in cold air of a building 1 exterior is connected to an intake line 6 midway part in a more downstream side, and a cold air damper 9 controlling a cold air flow rate is provided in a cold air line 8 midway part. A temperature detector 10 is provided for detecting an inlet side air temperature T of a forced draft fan 5, and a controller 11 is provided for outputting opening commands A1' and A2' to the hot air damper 7 and the cold air damper 9 such that the inlet side air temperature T becomes an inlet side air temperature set value T' based upon a boiler output MW. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an intake air temperature control method and apparatus for an indoor boiler installed in a building.

  Generally, a thermal power plant and other various plants are provided with a boiler, but the boiler may be installed in a building.

  FIG. 5 shows an example of a boiler installed in a conventional building, in which 1 is a building, 2 is a boiler body installed in the building 1 and generates steam by burning fuel such as coal or heavy oil, 3 is an air preheater (GAH) for exchanging heat between combustion exhaust gas discharged from the boiler body 2 and air such as combustion air supplied to the boiler body 2, and 4 is combustion supplied to the air preheater 3. Steam air heater (SAH) for heating air such as industrial air with steam to a temperature above the acid dew point and preventing corrosion of the air preheater 3 due to sulfur contained in the combustion exhaust gas, 5 is a steam air heater 4 and a forced draft fan (FDF) for blowing air to the boiler body 2 via the air preheater 3, and an intake line for sucking warm air in the upper part of the building 1 at the entry side of the forced draft fan 5 6 is connected There.

  In the boiler installed in the conventional building as shown in FIG. 5, warm air of about 30 to 40 [° C.] in the upper part of the building 1 is sucked from the intake line 6 by the operation of the forced draft fan 5, and steam The combustion exhaust gas discharged from the boiler body 2 is blown to the boiler body 2 through the air heater 4 and the air preheater 3, and fuel such as coal is burned in the boiler body 2 to generate steam. In the air preheater 3, the temperature is lowered by exchanging heat with air such as combustion air supplied to the boiler body 2 by the forced air blower 5, and then discharged from the chimney to the atmosphere.

  Note that nitrogen oxides, soot, and sulfur oxides contained in the combustion exhaust gas discharged from the boiler body 2 are removed and purified by a denitration device, an electrostatic precipitator, and a desulfurization device (not shown). Is released from the chimney into the atmosphere.

  As described above, the reason why the warm air in the upper part of the building 1 is sucked from the intake line 6 by the operation of the push-in ventilator 5 is to recover the heat radiation from the boiler body 2 and increase the efficiency. .

For example, Patent Document 1 discloses a technique for controlling the air temperature of a boiler so as to minimize heat that is discarded outside the system.
JP 2003-214621 A

  However, in the case of the indoor boiler as described above, in summer, the temperature of warm air in the upper part of the building 1 may reach 50 [° C.] or more, and the outlet gas temperature of the air preheater 3 rises, and the air Due to temperature restrictions of various devices (for example, an electrostatic precipitator and a desulfurization device) provided on the downstream side of the preheater 3, it is necessary to limit the load on the boiler body 2. There is a possibility that it may decrease and lead to a large loss, and the volume of exhaust gas increases as the outlet side gas temperature of the air preheater 3 rises, and the induction fan provided downstream of the air preheater 3 Auxiliary power such as (IDF) is increased, and the running cost is increased.

  In view of such a situation, the present invention can prevent the temperature of the intake air that is sucked by the forced air blower in the summer and supplied to the boiler body from rising more than necessary, and is associated with temperature limitations of various devices. It is an object of the present invention to provide an indoor boiler intake air temperature control method and apparatus which can eliminate the load limitation in the boiler body and can reduce the running cost by suppressing an increase in auxiliary power due to an increase in exhaust gas volume.

The present invention is an intake air temperature control method for an indoor boiler equipped with a forced air blower that draws warm air in the upper part of the building where the boiler body is installed and sends it to the boiler body,
Detecting the incoming air temperature of the forced air blower, and introducing the cold air of the outdoor part of the building to the incoming side of the forced air fan so that the incoming air temperature becomes an incoming air temperature set value based on the boiler output. The present invention relates to a feature of an indoor boiler intake air temperature control method.

In addition, the present invention is an intake air temperature control device for an indoor boiler equipped with a forced air blower that draws warm air in the upper part of the building where the boiler body is installed from the intake line and sends it to the boiler body,
A warm air damper for adjusting the flow rate of warm air provided in the middle of the intake line and sucked by the forced air blower;
A cold air line for taking in cold air from the outdoor part of the building and guiding it downstream from the warm air damper of the intake line;
A cold air damper for adjusting the flow rate of the cold air provided in the middle of the cold air line and sucked by the forced air blower;
A temperature detector for detecting the inlet air temperature of the forced draft fan;
A controller that outputs an opening degree command to the warm air damper and the cold air damper so that the inlet air temperature of the forced air fan detected by the temperature detector becomes an inlet air temperature set value based on the boiler output. The present invention relates to an intake air temperature control device for an indoor boiler, characterized in that it is provided.

In the indoor boiler intake air temperature control device, a first function generator for obtaining and outputting the inlet air temperature set value of the forced air blower based on the boiler output;
A subtractor that calculates and outputs a temperature difference between the inlet air temperature of the forced draft fan detected by the temperature detector and the inlet air temperature set value output from the first function generator;
A second function generator for obtaining and outputting a warm air damper opening bias command based on the temperature difference output from the subtractor;
An adder for adding the warm air damper opening bias command output from the second function generator to the warm air damper actual opening and outputting the warm air damper opening command to the warm air damper;
The controller can be configured from a third function generator that obtains a cold air damper opening command based on the warm air damper opening command output from the adder and outputs the command to the cold air damper.

  According to the above means, the following operation can be obtained.

  During operation, warm air in the upper part of the building in which the boiler body is installed is sucked in by the forced draft fan and sent to the boiler body. At this time, the inlet air temperature of the forced draft fan is detected, and the inlet air is detected. Since the cold air in the outdoor part of the building is introduced to the inlet side of the forced draft fan so that the temperature becomes the inlet side air temperature setting value based on the boiler output, the temperature of the warm air in the upper part of the building is assumed to be 50 [° C. in summer. ] Even if it reaches the above, the inlet side air temperature of the forced draft fan is always kept at the inlet side air temperature set value based on the boiler output, so that the outlet side gas temperature of the air preheater is too high. Is avoided, and there is no concern of affecting the various equipment (for example, an electrostatic precipitator or a desulfurization device) provided downstream of the air preheater, and it is not necessary to limit the load on the boiler body. Is provided on the downstream side of the air preheater, so that the electricity obtained does not decrease and does not suffer a large loss, and an increase in the volume of exhaust gas accompanying an increase in the outlet gas temperature of the air preheater is avoided. Auxiliary power such as an induction fan does not increase, and there is no need to worry about increased running costs.

  According to the intake air temperature control method and apparatus for an indoor boiler of the present invention, it is possible to prevent the temperature of the intake air that is sucked in by a forced air blower in the summer and supplied to the boiler body from rising more than necessary. It is possible to eliminate the load restriction on the boiler body due to the temperature restriction, and to achieve an excellent effect that the running cost can be reduced by suppressing an increase in auxiliary power due to an increase in the volume of exhaust gas.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 4 show an example of an embodiment for carrying out the present invention. In the figure, the same reference numerals as those in FIG. 5 denote the same components. A warm air damper 7 for adjusting the flow rate of the warm air to be sucked in is provided, and a cold air line 8 for taking in cold air outside the building 1 is connected to the intake line 6 downstream of the warm air damper 7. In the middle of the cold air line 8, a cold air damper 9 for adjusting the flow rate of the cold air sucked in by the forced air blower 5 is provided, and the incoming air temperature T of the forced air fan 5 is detected. The warm air damper 7 and the cool air damper 7 are cooled so that the inlet side air temperature T of the temperature detector 10 and the forced air blower 5 detected by the temperature detector 10 becomes the inlet side air temperature set value T ′ based on the boiler output MW. Opening command A1 ', A to air damper 9 'It is obtained by the provided and a controller 11 for outputting.

The controller 11
A first function generator 12 for obtaining and outputting an inlet air temperature set value T ′ of the forced draft fan 5 based on the boiler output MW;
A temperature difference (T−T ′) between the inlet air temperature T of the forced air blower 5 detected by the temperature detector 10 and the inlet air temperature set value T ′ output from the first function generator 12 is obtained. A subtractor 13 for outputting
A second function generator 14 for obtaining and outputting a warm air damper opening bias command ΔA1 based on a temperature difference (T−T ′) output from the subtractor 13;
An adder 15 for adding a warm air damper opening command A1 'output from the second function generator 14 to the warm air damper actual opening A1 and outputting a warm air damper opening command A1' to the warm air damper 7 When,
And a third function generator 16 for obtaining a cold air damper opening command A2 ′ based on the warm air damper opening command A1 ′ output from the adder 15 and outputting it to the cold air damper 9. is doing.

  As shown in FIG. 2, the first function generator 12 has a function for increasing or decreasing the inlet side air temperature set value T ′ of the forced draft fan 5 in a manner that is approximately inversely proportional to the increase or decrease of the boiler output MW. The higher the boiler output MW is, the lower the inlet side air temperature set value T ′ of the forced draft fan 5 is set.

  Further, as shown in FIG. 3, when the temperature difference (T−T ′) is a positive / negative value and falls within a predetermined allowable range, the second function generator 14 has a warm air damper opening bias. When the command ΔA1 is set to 0 and the temperature difference (T−T ′) is a positive value and deviates from the allowable range, the temperature difference (T−T ′) increases in the positive direction (indentation ventilation) As the incoming air temperature T of the machine 5 becomes higher), the warm air damper opening bias command ΔA1 is increased in the negative direction (direction in which the opening of the warm air damper 7 is reduced), and the temperature difference (T−T ′ ) Is a negative value and deviates from the permissible range, the larger the temperature difference (T−T ′) is in the negative direction (the inlet air temperature T of the forced air blower 5 is lower), A function for increasing the warm air damper opening bias command ΔA1 in the positive direction (in the direction of increasing the opening degree of the warm air damper 7). It is the force.

  Further, as shown in FIG. 4, when the warm air damper opening command A1 'is from 0 to a predetermined value, the third function generator 16 fully opens the cold air damper opening command A2' (100 [% )), And a function is input to decrease the cold air damper opening command A2 'as the warm air damper opening command A1' increases.

  Next, the operation of the illustrated example will be described.

  During operation, warm air in the upper part of the building 1 in which the boiler body 2 is installed is sucked from the intake line 6 by the forced draft fan 5 and sent to the boiler body 2. At this time, the inlet air of the forced draft fan 5 The temperature T is detected by the temperature detector 10 and input to the subtracter 13 of the controller 11, and the actual opening degree of the warm air damper 7 at that time, that is, the actual opening degree A1 of the warm air damper is determined by the controller. 11 adders 15.

  In the controller 11, the first function generator 12 obtains the inlet side air temperature set value T ′ of the forced draft fan 5 based on the boiler output MW and outputs it to the subtractor 13. A temperature difference (T−T ′) between the inlet air temperature T of the forced air blower 5 detected by the temperature detector 10 and the inlet air temperature set value T ′ output from the first function generator 12 is obtained. It is obtained and outputted to the second function generator 14, and the second function generator 14 obtains the warm air damper opening bias command ΔA1 based on the temperature difference (T−T ′) outputted from the subtractor 13. The warm air damper opening bias command ΔA1 output from the second function generator 14 is added to the warm air damper actual opening A1, and the warm air damper is output to the adder 15. Opening command A1 'is warm air The third function generator 16 outputs a cold air damper opening command A2 'based on the warm air damper opening command A1' output from the adder 15. And output to the cold air damper 9.

  Thereby, the cold air outside the building 1 is placed on the entry side of the forced air blower 5 so that the entry side air temperature T detected by the temperature detector 10 becomes the entry side air temperature set value T ′ based on the boiler output MW. Therefore, even if the temperature of the warm air in the upper part of the building 1 reaches 50 [° C.] or higher in summer, the incoming air temperature T of the forced draft fan 5 is always the incoming air based on the boiler output MW. Since the temperature is maintained at the temperature setting value T ′, it is avoided that the outlet gas temperature of the air preheater 3 is excessively increased, and various devices (for example, an electric dust collector) provided on the downstream side of the air preheater 3 are avoided. And the load on the boiler body 2 does not have to be affected. Especially in a power plant or the like, the obtained electricity does not decrease and does not suffer a large loss. Preheater The increase in the volume of the exhaust gas accompanying the rise in the outlet side gas temperature is avoided, and the auxiliary power such as an induction fan (IDF) provided on the downstream side of the air preheater 3 is not increased, which may increase the running cost. Also disappear.

  In addition, if the inlet side air temperature set value T ′ of the push-in ventilator 5 is set to a minimum temperature necessary for maintaining the cold end average metal temperature of the air preheater 3, it is only necessary when it is absolutely necessary in winter. Since it becomes possible to prevent the air preheater 3 from corroding due to sulfur contained in the combustion exhaust gas simply by starting the steam air heater 4, the frequency of use of the steam air heater 4 can be minimized and the efficiency can be improved. It becomes effective in raising.

  In this way, it is possible to prevent the temperature of the intake air sucked from the intake line 6 by the forced air blower 5 and supplied to the boiler main body 2 from rising more than necessary in the summer, and the boiler main body due to temperature restrictions of various devices. The load limit in 2 can be made unnecessary, and the running cost can be reduced by suppressing the increase in auxiliary power due to the increase in the volume of exhaust gas.

  Note that the indoor boiler intake air temperature control method and apparatus of the present invention are not limited to the illustrated examples described above, and various modifications may be made without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole schematic block diagram which shows an example of the form which implements this invention. It is a diagram which shows the function input into the 1st function generator of FIG. It is a diagram which shows the function input into the 2nd function generator of FIG. It is a diagram which shows the function input into the 3rd function generator of FIG. It is a whole schematic block diagram which shows an example of the boiler installed in the conventional building.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Building 2 Boiler body 5 Push-in ventilator 6 Intake air line 7 Intake line 7 Warm air damper 8 Cold air line 9 Cold air damper 10 Temperature detector 11 Controller 12 First function generator 13 Subtractor 14 Second function generator 15 Adder 16 Third function generator MW Boiler output A1 Warm air damper actual opening ΔA1 Warm air damper opening bias command A1 ′ Warm air damper opening command A2 ′ Cold air damper opening command T Incoming air temperature T ′ Incoming air temperature Set value TT 'Temperature difference

Claims (3)

An intake air temperature control method for an indoor boiler equipped with a forced air blower that sucks warm air in the upper part of the building where the boiler body is installed and sends it to the boiler body,
Detecting the incoming air temperature of the forced air blower, and introducing the cold air of the outdoor part of the building to the incoming side of the forced air fan so that the incoming air temperature becomes the incoming air temperature set value based on the boiler output. An indoor boiler intake air temperature control method. An intake air temperature control device for an indoor boiler equipped with a forced air blower that draws warm air in the upper part of the building where the boiler body is installed from the intake line and sends it to the boiler body,
A warm air damper for adjusting a flow rate of warm air provided in the middle of the intake line and sucked by a forced air blower;
A cold air line for taking in cold air from the outdoor part of the building and guiding it downstream from the warm air damper of the intake line;
A cold air damper for adjusting the flow rate of the cold air provided in the middle of the cold air line and sucked by the forced air blower;
A temperature detector for detecting the inlet air temperature of the forced draft fan;
A controller that outputs an opening degree command to the warm air damper and the cold air damper so that the inlet air temperature of the forced draft fan detected by the temperature detector becomes an inlet air temperature set value based on the boiler output. An intake air temperature control device for an indoor boiler, comprising: A first function generator for determining and outputting the inlet air temperature set value of the forced draft fan based on the boiler output;
A subtractor that calculates and outputs a temperature difference between the inlet air temperature of the forced draft fan detected by the temperature detector and the inlet air temperature set value output from the first function generator;
A second function generator for obtaining and outputting a warm air damper opening bias command based on the temperature difference output from the subtractor;
An adder for adding the warm air damper opening bias command output from the second function generator to the warm air damper actual opening and outputting the warm air damper opening command to the warm air damper;
The indoor boiler according to claim 2, wherein the controller is configured by a third function generator that obtains a cold air damper opening command based on a warm air damper opening command output from the adder and outputs the cold air damper opening command to the cold air damper. Intake air temperature control device.

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