KR0143698B1 - The method of concentrated liquid for a boiler - Google Patents

Abstract

The present invention relates to a method for removing condensate attached to a boiler heat exchanger. More specifically, the present invention relates to a condensate removal method of a boiler that can remove condensate formed by condensation of gas and water vapor discharged through exhaust flue, thereby preventing corrosion of the heat exchanger and extending its life.

In the method of removing condensate in a boiler of the present invention, when the boiler is operated, the temperature of the waste gas discharged through the exhaust flue is measured, and when the temperature of the waste gas is less than a predetermined temperature, heat is applied to the surface of the heat exchanger to heat the temperature of the heat exchanger. It is characterized by increasing the vaporization of the condensate.

Description

How to remove condensate from boiler

1 is a cross-sectional view showing a schematic structure of an exhaust hood and a heat exchanger of a conventional gas boiler;

2 is a flowchart illustrating a condensate removal method of the present invention,

3 is a schematic circuit diagram for performing the condensate removal method of the present invention,

4 is an installation state diagram of a heater installed on the surface of a heat exchanger according to the present invention.

* Explanation of symbols for main parts of the drawings

2: Exhaust year 4: Exhaust fan

6: heat exchanger 8: burner

10: combustion chamber 12: heater

12-1: Heating element 14: Temperature sensor

16: Control microcomputer 18: Timer

R, R1: Resistance C1: Capacitor

The present invention relates to a method for removing condensate attached to a boiler heat exchanger. More specifically, the present invention relates to a condensate removal method of a boiler that can remove condensate formed by condensation of gas and water vapor discharged through exhaust flue, thereby preventing corrosion of the heat exchanger and extending its life.

When the temperature of the waste gas discharged to the outside through the exhaust flue during the use of the gas boiler is lowered, condensate is generated by combining the steam and waste gas contained in the gas. Since the condensate has a strong acid property, there is a possibility of causing fatal damage to heat exchangers and components installed in the gas boiler.

In particular, in the proportional control gas boiler, the temperature of the heating water tends to be lowered as the outdoor temperature increases, thereby reducing the temperature of the waste gas generated after the fuel is burned. In general, the temperature of the waste gas discharged to the outside through the exhaust flue is about 130 ~ 150 ℃ in the exhaust flue, while the proportional control method is less than 70 ℃ occurs.

In addition, even when the operation of the gas boiler is stopped, the temperature of the waste gas is drastically lowered to generate strong acid condensate.

1 is a schematic cross-sectional structure diagram of a conventionally used gas boiler, in which a heat exchanger 6 is positioned under the exhaust flue 2, and a burner 8 for burning fuel is installed below the heat exchanger 6. have. And the combustion chamber is provided so that the burner 8 may be enclosed. The combustion chamber is arranged to surround the sides and the bottom of the heat exchanger 6 and the burner 8, so that the hot combustion gas generated in the burner 8 moves only upwards, and the hot combustion gas is transferred to the heat exchanger 6 Heat is exchanged with the water inside the heat exchanger 6 while passing between the gaps of the heat exchanger 6. In practice, the heat exchanger 6 and the burner 8 are configured to block the movement of air to the outside by the external combustion chamber 10 as shown in FIG.

In the case of the forced exhaust system, the waste gas combusted by the burner 8 is discharged through the exhaust pipe 4 that passes through the exhaust flue 2 by the exhaust fan 4 and extends to the outside. Since the exhaust flue 2 is mostly installed outside the boiler, the discharged waste gas is cooled in direct contact with the external low temperature. According to the experiment, condensation occurs when the temperature of the waste gas passing through the exhaust flue 2 is 70 ° C. or lower. This happens easily.

The condensed water flows down the exhaust flue 2 to the lower side and falls to the surface of the heat exchanger 6. Since condensate contains strong acidic components, corrosion occurs when used for a long time, and a hole is formed in the surface of the heat exchanger 6, thereby causing a problem in that the boiler is broken.

The cause of such strong acid condensate will be described in detail as follows. The acidic components contained in the condensate are due to N ₂ and S contained in the air. That is, the waste gas remaining after the combustion of fuel and oxygen in the air contains CO, CO ₂ , NO _X , SO _X , and the like. In particular, combustion in gas boilers produces 1.2 to 1.6 times more excess air than natural combustion, resulting in more CO, CO ₂ , NO _X , SO _X , etc.

On the other hand, when the fuel LNG or LPG (LNG is the main character CH ₄ , LPG is the main component is C ₃ H ₈ ) is burned, as shown in the following equation, water (H 2 O) is generated.

* LNG combustion *

LPG combustion

At this time, the generated water (H ₂ O) is a state of steam vaporized by high temperature heat, is included in the waste gas and is discharged to the outside. In this way, when discharged to the waste gas at a high temperature state, such as CO, CO ₂ , NO _X , SO _X , is discharged to the outside does not cause any problem.

However, as described above, when the temperature of the waste gas passing through the exhaust flue 2 is 70 ° C. or less, water vapor condenses and is combined with NOX and SOX discharged together to exhibit strong acidity. This is clarified by the following equation.

As shown in the above formula, the condensate has a strong acidity. As is well known, since acid has a property of dissolving metal, a heat exchanger mainly made of copper is punctured by an acid, so that the heat exchanger is broken, and in the case of severe damage, the heat exchanger has to be replaced.

The present invention has been made to solve the above problems, the present invention provides an acid condensate generated in the exhaust flue of the boiler to provide a condensate removal method of the boiler to prevent corrosion of the heat exchanger and extend the life. For the purpose of

Condensate removal method of the boiler of the present invention to achieve the above object, by measuring the temperature of the waste gas discharged through the exhaust flue when the boiler is operated, when the temperature of the waste gas is below a predetermined temperature, by applying heat to the surface of the heat exchanger The temperature of the heat exchanger is increased to vaporize the condensate.

Hereinafter, a method of removing condensate in the boiler of the present invention will be described in detail with reference to FIGS. 2 to 4.

According to the method of the present invention, when the boiler is operated, a first step of continuously inputting the temperature of the waste gas into the control microcomputer from a temperature sensor installed inside the exhaust flue, and whether the temperature input in the first step is higher than or equal to a predetermined temperature; In order to judge the application, the control microcomputer whose temperature is set and stored in advance does not output any control signal when the input temperature is higher than the predetermined temperature, and operates the boiler normally, and when the temperature is lower than the predetermined temperature, outputs the control signal to operate the timer. And a third step of determining whether the input temperature is higher than or equal to a predetermined temperature when the operation time by the timer elapses; and a surface of the heat exchanger if the input temperature is lower than or equal to a predetermined temperature as a result determined in the third step. A fourth outputting control signal from the control microcomputer to operate the heater attached to the System and, if the re-entered temperature after the heater is operating is determined from whether the controlling microcomputer is not applied more than the predetermined temperature equal to or less than a predetermined temperature is still operating the heater and a predetermined temperature or higher and is composed of a fifth step of stopping the operation of the heater.

When the boiler is operated, a signal is input from the temperature sensor 14 installed inside the exhaust flue. The temperature sensor 14 may use a general device, for example, a thermostat, in which a resistance changes according to a temperature change. The generated voltage is input to the control microcomputer 16 which is a device for comparing and determining the temperature corresponding to the corresponding voltage and the set temperature.

The preset temperature is input to the control microcomputer 16. This set temperature is a temperature at which the waste gas passing through the exhaust flue 2 is condensed due to the characteristics of the present invention, and becomes about 70 ° C. The set temperature is mainly stored in a memory element built in the control microcomputer 16.

The electrical signal input from the temperature sensor 14 is converted into a corresponding temperature signal at the control microcomputer 16 and compared with a preset stored temperature. As a result of the comparison, when the input temperature is larger than the set temperature, no condensation occurs, so that the control microcomputer 16 does not output any control signal to operate the boiler normally.

When the input temperature is lower than the set temperature, the control microcomputer 16 determines that it is condensed into the waste gas, and operates the timer 18. The timer 18 may connect an external timer or use a timer installed therein as shown. The reason for operating the timer 18 is to delay the time until the waste gas discharged at the beginning of the boiler operation is mostly operated at a low temperature and is sufficiently operated to combust normally. This timer setting time is preferably about 2 to 3 minutes. While the timer 18 is operating, the control microcomputer 16 may be set to ignore the signal input from the temperature sensor 14.

After the predetermined time has elapsed, when the operation of the timer 18 is stopped, the control microcomputer 16 reads back the current temperature from the temperature sensor 14, and sets the set temperature and the input temperature as described above. Compare again. As a result of the comparison, if the input temperature is higher than the set temperature (above 70 ° C), it operates normally, and if it is low (below 70 ° C), it is judged that condensed water is generated, Activate heater 12. This raises the temperature of the heat exchanger and causes the condensate to evaporate. The heater 12 may be used to include a heating wire that is a heating element therein.

Even after the heater 12 is operated, the control microcomputer 16 continuously measures the current temperature from the temperature sensor 14 to stop the operation of the heater 12 when the input temperature is higher than the set temperature (above 70 ° C). The temperature is measured continuously again.

FIG. 3 is a schematic circuit diagram configured to carry out the present invention, which is installed inside the exhaust flue 2 and has a temperature sensor 14 and a resistance value corresponding to a temperature change, and the temperature sensor 14 The control input is compared with a preset temperature signal stored therein, and the control microcomputer 16 controls to perform the necessary stroke, and is operated by the control signal of the control microcomputer 16 attached to the surface of the heat exchanger. Heater 12 and a timer 18 for measuring the passage of a predetermined time. The resistor R is a voltage dividing resistor, and the resistor R1 and the capacitor C1 are elements for removing noise input from the temperature sensor 14.

The temperature sensor 14 may use a device that is generally used, it is preferable to use a device that changes the resistance value or changes the electromotive force according to the temperature change. In addition, the installation position is also installed in the middle portion inside the exhaust flue (2).

However, the temperature sensor 14 according to the present invention may be provided outside the exhaust flue 2 in order to prevent exposure to the exhaust gas directly. In this case, precise temperature setting is required and can be obtained by experiment.

The control microcomputer 16 preferably uses a general-purpose IC that can output the necessary control signal by comparing the input voltage with the set voltage. It will be appreciated that other integrated circuits may be used for this purpose.

Referring to FIG. 4, the heater 12 may be attached to the surface using an adhesive because the outer surface of the conventional heat exchanger 6 is flat. The heater 12 is connected to the control microcomputer 16 by an electric wire. The heater 12 includes a heating element 12-1 therein, and the outside thereof is wrapped with a nonflammable material. However, the heater can be used as long as it is different from the above as long as it has a strong heat resistance property.

As described above, according to the present invention, the acid condensate generated in the exhaust flue of the boiler can be removed to prevent corrosion of the heat exchanger and to extend the service life.

Although the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that modifications and variations can be made within the spirit and scope of the invention, and such variations or modifications are limited by the appended claims. You must lose.

Claims (3)

A first step of inputting the temperature of the waste gas into the control microcomputer 16 from the temperature sensor 14 installed in the exhaust flue 2 when the boiler is operated; The control microcomputer 16, which has a preset temperature for determining whether the temperature input in the first step is above or below a predetermined temperature, stores the input temperature above a predetermined temperature and does not output any control signal to operate the boiler normally. A second step of outputting a control signal to operate the timer 18 when the temperature is lower than the predetermined temperature; A third step of determining whether the input temperature is equal to or higher than a predetermined temperature when the operation time by the timer 18 elapses; A fourth step of outputting a control signal from the control microcomputer 16 to operate the heater 12 attached to the surface of the combustion chamber 10 when the input temperature is less than a predetermined temperature as a result determined in the third step; And after the heater 12 is operated again, the control microcomputer 16 determines whether the input temperature is higher than or equal to the predetermined temperature and continues to operate the heater 12 when the temperature is lower than the predetermined temperature. Condensate removal method of the boiler comprising a fifth step of stopping. The method of claim 1, wherein the timer (18) has an operating time of 2 to 3 minutes. The method of claim 1, wherein the temperature sensor (14) is a thermostat.