KR20110059392A - Equipment and method of elimination of deposits on the heating elements of ggh for wet flue gas desulfurization systems - Google Patents

Abstract

PURPOSE: Equipment and method for removing deposits from a gas heat exchanger for a wet flue-gas desulfurization system are provided to efficiently remove scales from a GGH(Gas-Gas Heater) heat element since the GGH element is cleaned by high temperature and pressure of water. CONSTITUTION: Equipment(100) for removing deposits from a gas heat exchanger for a wet flue-gas desulfurization system comprises a cleaning tub(110), a water tank(120), and a pump(130). A GGH heat element, on which scales are deposited, is put into the cleaning tub. Cleaning solution or water is sprayed from the inner upper part of the cleaning tub. The water tank heats the cleaning solution or water to a given temperature. The pump supplies the cleaning solution or water from the water tank to the cleaning tub.

Description

Gaseous heat exchanger sediment removal device and removal method for wet flue gas desulfurization facility {EQUIPMENT AND METHOD OF ELIMINATION OF DEPOSITS ON THE HEATING ELEMENTS OF GGH FOR WET FLUE GAS DESULFURIZATION SYSTEMS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas heat exchanger deposit removal device and a method for removing the wet heat desulfurization plant, and in particular, is deposited or deposited on the surface of a heat element of a gas-gas preheater (Gas-Gas Heater, GGH) to reduce the heat exchange efficiency of GGH. The present invention relates to a gas heat exchanger deposit removal device and a method for removing a scale (or deposit) that easily impedes gas flow.

1 is a perspective view showing a gas-gas heat exchanger (GGH) of the wet flue gas desulfurization facility, Figure 2 is a photograph showing the heat element before it is installed and used in the GGH, Figure 3 is a one-year operation time of the GGH A picture showing one thermal element.

In a thermal power plant, a gas-gas preheater (Gas-Gas Heater, GGH) 10 of the type shown in FIG. 1 is widely used for heat exchange (between flue gas and desulfurized gas) of a wet flue gas desulfurization facility. In this GGH, carbon steel heat elements (Heating Elements) 11 performing heat exchange between two gases are configured in a bundle or cell form parallel to the air stream.

As shown in FIG. 2, the carbon steel heating element 11 is processed in a wave shape in a cross-section, and is assembled such that acid and acid are opposed to each other, thereby increasing heat exchange efficiency and not being swept away by the airflow. In addition, in order to increase the corrosion resistance of the carbon steel thermal element, the enamel of the glass component on both sides of the thermal element is coated with a thickness of 100 ~ 200㎛.

When the GGH having such a configuration is used in a wet flue gas desulfurization system using a limestone slurry as a desulfurization agent, as shown in FIG. 3, gypsum generated in a reactor (absorption tower) of the facility is not completely removed and is introduced with moisture to induce GGH. It is deposited on the inside and the surface of the heating element on the scale, which lowers the heat exchange rate of the heating element and hinders the flow of flue gas.

In addition, it absorbs fine solid coal ash in flue gas and becomes solid and at the same time acidic under the influence of SO ₂ gas included in flue gas, promoting physical and chemical damage of enamel coating to prevent corrosion and ultimately life of enameled thermal element. It also lowers the corrosion and increases the corrosion of equipment.

In order to solve this problem, most power plants periodically clean scales deposited on the surface of a thermal element by using a high-temperature, high-pressure water or steam with a GGH shot blower. In this process, the gypsum component is easily washed in water, but components such as silica and alumina contained in the scale are not easily removed.In order to increase the efficiency of removing the scale, the pressure of the shot blower is increased to increase the GGH heating element (especially from the absorption tower). There is a problem that the damage of the first contact with the gas) is accelerated.

An object of the present invention is to solve the above-mentioned problems, it is possible to efficiently remove the scale deposited on the GGH heating element, and the wet desulfurization equipment for preventing damage to the GGH heating element during the cleaning process The present invention provides a gas heat exchanger deposit removal device and a removal method.

In order to achieve the above object, the present invention is a gas heat exchanger deposit removal device for a wet-row desulfurization facility, a washing tank into which a scale-deposited GGH heating element is introduced, and a washing liquid or water is injected from the inner upper portion; A bath for heating the washing liquid or water to a constant temperature; And a pump for supplying the washing liquid or water in the tank to the washing tank.

The present invention preferably further includes a filter for removing solids contained in the washing liquid or water circulated from the washing tank to the water tank.

The washing solution is preferably a caustic soda solution of 1 to 5% by weight.

The washing solution is preferably 1 to 5% by weight of hydrochloric acid or citric acid solution.

It is preferable that the temperature of the said washing | cleaning liquid is 40-90 degreeC.

The injection flow rate of the washing liquid is preferably 1 ~ 10L / min / ㎡.

In order to achieve the above object, the present invention is a method for removing a gas heat exchanger deposit for a wet-array desulfurization plant, the method comprising: introducing a scaled thermal element into a washing tank, heating the washing liquid to a constant temperature in a water tank, and heating the heated washing liquid. Supplying to the washing tank, spraying the washing liquid from the upper portion of the washing tank to wet the thermal element, and filtering the washing liquid used for washing to recycle the washing liquid.

In the supplying step of the washing liquid, it is preferable that the acidic washing liquid and the alkaline washing liquid are alternately supplied.

The gas heat exchanger deposit removal method for a wet heat desulfurization plant of the present invention further includes the step of washing with high temperature and high pressure water at an alternate time between the acidic washing liquid and the alkaline washing liquid.

The acidic washing liquid and the alkaline washing liquid are sprayed alternately for 1 to 5 hours, and the water is sprayed in a state of 40 to 90 ° C. and 5 to 30 atmospheres.

According to the gas heat exchanger deposit removal device and removal method for a wet heat desulfurization facility according to the present invention, after the acid washing liquid and the alkaline washing liquid are alternately sprayed to wet the GGH heating element, the alternating time of the acid washing liquid and the alkaline washing liquid By washing with high temperature and high pressure water, the scale deposited on the GGH thermal element can be removed efficiently and the damage of the GGH thermal element can be prevented. Therefore, the heat exchange efficiency of GGH can be increased.

In addition, if the sediment removal device according to the present invention is configured as one system of the flue gas desulfurization facility and applied to the scale deposited on the surface of the GGH heat element during the operation of the flue gas desulfurization facility, the scaled heat device is not separated from the GGH. It can be easily cleaned by high temperature and high pressure water during maintenance.

In addition, according to the operating conditions of the power plant can be quickly removed regardless of the type of sediment of various components can shorten the maintenance period of the facility.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 is a system diagram showing a gas heat exchanger deposit removal device for a wet heat desulfurization facility according to the present invention, Figure 5 is a photograph showing a state in which the washing liquid is dispersed from the top of the washing tank of FIG.

Gas heat exchanger deposit removal apparatus 100 for a wet heat desulfurization facility according to the present invention includes a washing tank 110, a water tank 120, a pump 130, and a filter 140, as shown in FIG. .

The washing tank 110 has a gas-gas preheater (GGH) introduced therein, and a plurality of injection holes 110a for spraying the washing liquid or water are formed in the upper portion of the washing tank 110. .

The water tank 120 is for heating the washing liquid or water to a predetermined temperature, the heater 121 is installed at the bottom. In the water tank 120, a thermometer 122 for detecting a temperature is installed. The water tank 120 is preferably partitioned into three storage spaces so as to store the acid solution, the alkaline solution and the water, respectively, but is not limited thereto. Each tank includes three tanks for storing the acid solution, the alkaline solution and the water. It may be configured to replace the respective tanks step by step in the post-cleaning process. In addition, the acid solution and the alkaline solution may be respectively provided with a water tank, and the water may be configured to be supplied from the outside.

As the washing solution, an alkaline solution (caustic soda) and an acid solution (hydrochloric acid or citric acid) are used. The concentration of each solution is 1 to 5% by weight, and the heating temperature is preferably 40 to 90 ° C. If the concentration of the solution is less than 1%, the effect of removing the scale is insignificant. If it exceeds 5%, the enamel layer coated on the thermal element may be damaged. When the temperature of the solution is less than 40 ° C., the effect of removing the scale is insignificant. When the temperature of the solution exceeds 90 ° C., the evaporation rate of the water is increased, thereby increasing the concentration of the solution.

The pump 130 supplies the washing liquid or water of the water tank 120 to the washing tank 110 to spray from the upper portion of the washing tank 110.

The filter 140 is installed on a circulation path connecting the washing tank 110 and the water tank 120 to filter the solids contained in the washing liquid or water discharged from the washing tank 110.

On the other hand, the pressure control valve 150 and the pressure gauge 160 for adjusting the injection pressure of the washing liquid or water to be sprayed on the transport pipe connected to the washing tank 110 from the pump 130 is installed.

Hereinafter, a process of removing the deposits by using the gas heat exchanger deposit removal device for the wet heat desulfurization facility configured as described above will be described in detail. Figure 6 is a flow chart showing a method for removing the gas heat exchanger deposits for the wet heat desulfurization facility according to the present invention.

First, the washing tank 110 is introduced into the GGH heating element for washing (S10).

The washing liquid and water of a certain concentration is injected into the water tank 120, and the injected washing liquid and water are heated to a predetermined temperature by the operation of the heater 121 (S20). The concentration of the washing liquid is 1 to 5% by weight, the heating temperature is preferably 40 ~ 90 ℃. As for the heating temperature of water, 40-90 degreeC is preferable.

The washing liquid heated to a predetermined temperature in the water tank 120 is transferred to the washing tank 110 by the pump 130 and then sprayed toward the GGH heating element through the injection hole 110a formed in the upper portion of the washing tank 110 (S30). ). The injection time varies depending on the concentration and temperature of the solution, but is preferably 1 to 10 hours. The higher the concentration and temperature of the washing solution, the shorter the injection time.

In addition, one type of solution (for example, acid solution) is wetted by spraying for a predetermined time, and then washed with high temperature and high pressure water, and then another type of solution (alkaline solution) is sprayed and wetted for some time, followed by washing with hot and high pressure water. It is preferable. The acidic washing liquid and the alkaline washing liquid are sprayed alternately for 1 to 5 hours, the temperature of the high-temperature high-pressure washing water sprayed at the alternate time is preferably 40 to 90 ° C., and the pressure is 5 to 30 atmospheres.

It is preferable that the flow rate at the time of spraying washing liquid is 1-10 L / min / m <2>. If the flow rate is too small, the temperature of the thermal element is not maintained, the scale removal effect is insignificant, and if the flow rate is too large, there is a problem that the capacity of the equipment is too large for the circulation of the washing liquid.

The washing time is preferably 30 seconds to 2 minutes in the washing with high temperature and high pressure water after soaking the GGH heating element. One minute removes most of the scale and more than two minutes does not increase the cleaning effect.

On the other hand, when the washing is completed in the washing tank 110, the washing liquid and water is recycled to the water tank 120 and in the process solids are filtered while passing through the filter 140 (S40).

Example 1

For the test of Example 1 of the present invention, a GGH thermal element carbon steel sheet used for two years at a plant A site was collected. Both sides of the thermal element are coated with an enamel having a thickness of about 150 mu m, and scales are deposited as shown in FIG. The thermal elements were stacked as shown in FIG. 7 (a) and placed in a washing bath of FIG.

The wash solution used a caustic soda solution of 3% by weight and the temperature was set to 80 ℃. The spraying rate of the washing solution was set at 5 L / min / m 2 for 6 hours, and then washed with 20 atm and 70 ° C. water. Washing results are shown in FIG. 8. As shown in FIG. 8, the scale is completely detached from the upper part (a part of the right part, but the lower part remains a considerable part.

Example 2

For the test of Example 2 of the present invention, the same thermal element as in Example 1 was used and the same test procedure was performed. However, in this example, 5% by weight of caustic soda solution was used as the washing solution and the temperature was adjusted to 80 ° C. The injection time was 24 hours and washed with water at 20 atm, 70 ℃. Washing results are shown in FIG. 9. As can be seen in Figure 9 it can be seen that most of the scale is completely detached. However, in this case, since it requires a lot of injection time it can be seen that the practicality is poor.

Example 3

For the test of Example 3 of the present invention, GGH thermal element carbon steel sheet used for 4 years at the plant B site was collected. An enamel of about 150 mu m thickness was coated on both surfaces of the thermal element, and scales were deposited as shown in FIG.

The thermal elements were stacked as in FIG. 10 (a) and placed in a washing bath of FIG. 4 to perform a washing test. The wash was sprayed with hydrochloric acid solution at 3% by weight and 80 ° C. at 5 L / min / m 2 for 2 hours, then washed with 20 atm and 70 ° C. water, followed by 3 hours with 5% by weight 80 ° C. caustic soda solution. It was sprayed at the same rate and washed with water at 70 ° C. at 20 atmospheres. Washing results are shown in FIG. 11. As shown in FIG. 11, it can be seen that most of the scales were completely detached, and the washing was performed in a considerably short time compared to Example 2.

As described above, although described based on the preferred embodiment according to the present invention, the present invention is not limited to the specific embodiment, can be changed within the scope described in the claims by those of ordinary skill in the art have.

1 is a perspective view showing a gas-gas heat exchange facility (GGH) of the wet flue gas desulfurization facility.

Figure 2 is a photograph showing the thermal element before being installed and used in the GGH.

Figure 3 is a photograph showing the thermal element of which the operating time of the GGH is one year.

Figure 4 is a system diagram showing a gas heat exchanger deposit removal device for a wet heat desulfurization facility according to the present invention.

5 is a photograph showing a state in which the washing solution is dispersed from the top of the washing tank of FIG.

Figure 6 is a flow chart showing a method for removing the gas heat exchanger deposits for the wet heat desulfurization facility in accordance with the present invention.

Figure 7 is a photograph showing a heating element bundle and one heating element before cleaning in Examples 1 and 2 of the present invention.

Figure 8 is a photograph showing one thermal element washed by Example 1 of the present invention.

Figure 9 is a photograph showing one thermal element washed by Example 2 of the present invention.

10 is a photograph showing a heating element bundle and one heating element before washing in Example 3 of the present invention.

Figure 11 is a photograph showing a thermal element bundle and one thermal element washed in Example 3 of the present invention.

<Explanation of symbols for the main parts of the drawings>

110: washing tank 120: water tank

121: heater 122: thermometer

130: pump 140: strainer

150: pressure control valve 160: pressure gauge

Claims (10)

A washing tank into which a scale-deposited GGH heating element is introduced, and a washing liquid or water is sprayed from the inner upper portion; A water bath for heating the washing liquid or water to a predetermined temperature; And And a pump for supplying a washing liquid or water in the tank to the washing tank. The method of claim 1, And a filter for removing the solids contained in the washing liquid or water circulated from the washing tank to the water tank. The method according to claim 1 or 2, The washing solution is a gas heat exchanger deposit removal device for a wet-row desulfurization facility, characterized in that the caustic soda solution of 1 to 5% by weight concentration. The method according to claim 1 or 2, The washing solution is a gas heat exchanger deposit removal device for a wet heat desulfurization facility, characterized in that 1 ~ 5% by weight of hydrochloric acid or citric acid solution. The method of claim 1, The temperature of the washing liquid is a gas heat exchanger deposit removal device for a wet array desulfurization facility, characterized in that 40 ~ 90 ℃. The method of claim 1, The gas flow exchanger deposit removal device of the wet-row desulfurization facility, characterized in that the injection flow rate of the washing liquid is 1 ~ 10L / min / ㎡. Introducing a scaled thermal element into the washing tank; Heating the washing liquid to a constant temperature in a water bath; Supplying a heated washing liquid to the washing tank; Spraying the washing liquid from the upper portion of the washing tank to wet the thermal element; And And filtering the washing liquid used for washing to recycle the washing liquid to the water tank. The method of claim 7, wherein The method of removing the gas heat exchanger deposit for the wet-row desulfurization facility, characterized in that in the supplying step of the washing solution, an acidic washing solution and an alkaline washing solution are alternately supplied. The method of claim 8, The method of removing a gas heat exchanger deposit for a wet-row desulfurization facility, characterized in that it further comprises the step of washing with high temperature and high pressure water at the time of alternating acidic and alkaline washing liquid. The method of claim 9, The acidic washing liquid and the alkaline washing liquid are alternately supplied and sprayed for 1 to 5 hours, and the water is sprayed in a state of 40 to 90 ° C. and 5 to 30 atmospheres. .

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