KR20050043355A - Method for improving thermal efficiency and removing white plume from flue gas, and fuel additive therefor - Google Patents

Abstract

The present invention relates to a method for improving boiler thermal efficiency and / or removing visible white smoke and a fuel additive therefor. More specifically, by adding a fuel additive containing magnesium as a main ingredient and an emulsifier for improving combustion, directly to the fuel containing sulfur, the temperature of the exhaust gas is lowered to improve the thermal efficiency of the boiler and at the same time, sulfur contained in the exhaust gas after combustion. A method for removing visible oxides of combustion gases exiting a stack by removing oxides and a fuel additive therefor.

In the method of improving boiler thermal efficiency and / or removing visible white smoke, the present invention provides (a) fueling a magnesium slurry containing a magnesium compound and a hydrocarbon solvent to the burners 216a, 216b, 216c, and 216d of the boiler 200. Injecting into the fuel supply pipe 210; And (b) injecting an emulsifier comprising a hydrocarbon solvent, water, and a surfactant into the front of the burners (216a, 216b, 216c, 216d) to improve boiler thermal efficiency and / or remove visible white smoke. do.

The present invention also provides magnesium slurries and emulsifiers for use in boiler thermal efficiency enhancement and / or visible white smoke removal methods.

Description

Method for Improving Thermal Efficiency And Removing White Plume from Flue Gas, And Fuel Additive Therefor}

The present invention relates to a method for improving boiler thermal efficiency and / or removing visible white smoke and a fuel additive therefor. More specifically, by adding a fuel additive containing magnesium as a main ingredient and an emulsifier for improving combustion, directly to the fuel containing sulfur, the temperature of the exhaust gas is lowered to improve the thermal efficiency of the boiler and at the same time, sulfur contained in the exhaust gas after combustion. A method for removing visible oxides of combustion gases exiting a stack by removing oxides and a fuel additive therefor.

Fuel oil, such as boilers and furnaces in thermal power plants, steel mills, factory facilities or central heating facilities, are mainly used for fuel. Heavy oil is commonly referred to as bunker-C oil and is divided into high sulfur heavy oil and low sulfur heavy oil according to the weight ratio of sulfur contained in heavy oil. Low sulfur heavy oil is mainly used in boilers and power plants.

By the way, it is presented contains sulfur dioxide (SO ₂₎ and sulfur trioxide (SO ₃₎ sulfur oxides (SO _x) such as the exhaust gas (Flue Gas) is discharged after combustion by using a fuel containing a sulfur. Since the sulfur oxides cause not only air pollution but also acid rain, it is common to install and operate a flue gas desulfurization (FGD) to remove sulfur oxides contained in exhaust gas.

However, even when the flue gas desulfurization facility is operated, the exhaust gas discharged to the stack includes air pollutants such as sulfur oxides. Even if the emitted air pollutants are discharged within the legal regulations, the exhaust gas has an opaque color called plum opacity, which is a subject of complaints due to psychological anxiety. It may cause contamination.

On the other hand, the main causes of visible white lead are the condensation of moisture due to the difference in humidity between the exhaust gas and the atmosphere, the scattering of light by nitrogen oxides (NOx) present in the exhaust gas, and the sulfuric acid mist produced by condensation of sulfur trioxide (SO ₃ ). The thing by the scattering and absorption phenomenon of the light by (Mist) is mentioned. The most problematic of these is caused by sulfur oxides, which are reported to be produced even when only about 5 to 10 ppm (Part Per Million) of sulfur trioxide (SO ₃ ) is present in the exhaust gas. It is much lower than the legally acceptable concentration for sulfur oxides (SOx) that may be included.

The causes of sulfuric acid mist emissions to the atmosphere are as follows.

Exhaust gas generated from the boiler is passed through an electrostatic precipitator (EP) to remove dust and ash contained in the exhaust gas, and to remove sulfur oxides contained therein through a desulfurization facility such as an absorption tower. The exhaust gas is discharged to the outside through the stack through a gas-gas heater, in which heat exchange between the exhaust gas and the exhaust gas is performed after desulfurization.

In this process, when the exhaust gas enters the desulfurization plant, cooling is performed at a high speed. At this time, sulfur trioxide is condensed to form an ultrafine mist of sulfuric acid. The main formula of sulfuric acid mist production is the same as the general formula (1).

The average diameter of sulfuric acid mist is about 0.1 to 0.3 µm, and the mist eliminator installed in the absorption tower is not sufficiently removed, and some of the sulfuric acid mist is stuck to the gas-gas heater during the discharge process and the rest is stacked. Through the atmosphere.

Typically the concentration of sulfur trioxide in the exhaust gas is from about 1% to as high as about 5% of the sulfur dioxide concentration in the exhaust gas. However, vanadium (V) contained in heavy oil is known to play a catalytic role in the conversion of sulfur dioxide to sulfur trioxide at about 430 ° C. Therefore, when using high sulfur heavy oil as fuel, there is a great concern about the occurrence of sulfur trioxide.

In order to remove the sulfur trioxide, various conventional techniques have been used. Representative methods include a wet electrostatic precipitator, a method of spraying water, hydrated lime (Ca (OH) ₂ ) or sodium bicarbonate (NaHCO ₃ : Sodium). Bicarbonate), ammonia (Ammonia: NH ₃ ) or limestone (Limestone: CaCO ₃ ), such as a method of injecting an absorbent.

The wet electrostatic precipitator is installed at the rear of the flue gas desulfurization plant (FGD), but the removal rate of sulfur trioxide is shown to reach about 60 to 70%, but there is a problem in that the initial investment cost is high because a separate device must be installed.

The water spray method is a method of preventing the generation of sulfur trioxide by lowering the temperature of the exhaust gas below the acid dew point by spraying water in front of the electrostatic precipitator without a separate absorbent. However, as the temperature of the exhaust gas is lowered and the humidity is higher, the electrical resistance of the particles in the exhaust gas is lowered, causing re-scattering in the electrostatic precipitator. Thus, there is a problem in that dust collection efficiency is lowered.

On the other hand, the method of injecting the absorbent into the duct of the electrostatic precipitator for the removal of sulfur trioxide has the following characteristics.

Slaked lime removes sulfur trioxide by a reaction such as the formula (2).

Slaked lime is cheaper than other absorbents and has high sulfur trioxide removal efficiency, but has a disadvantage in that the performance of the electrostatic precipitator decreases and the generation of white smoke is increased when the injection is excessive.

Sodium bicarbonate removes sulfur trioxide by a reaction as shown in Formula 3, but does not reduce the performance of the electrostatic precipitator, but has a disadvantage that the price is three times higher than that of slaked lime.

Ammonia removes sulfur trioxide by a reaction as shown in formula (4).

Ammonia has an excellent effect on the removal of sulfur trioxide, and the ammonia salts produced through the process of Chemical Formula 4 are removed in the electrostatic precipitator. However, unreacted ammonia or ammonia salts are adsorbed on fly ash, causing ammonia odors during the treatment of fly ash, which is disposed of.

Limestone removes sulfur trioxide by a reaction such as the formula (5).

Limestone is injected from a flue gas desulfurization plant (FGD), which is easier to use than other absorbents and has the advantage of obtaining gypsum (CaSO ₄ · 2H ₂ O) as a by-product, but the sulfur trioxide removal efficiency is lower than that of other absorbents. .

On the other hand, it is known that vanadium (Vanadium) contained in the fuel serves as a catalyst as the main cause of the generation of sulfur trioxide in the combustion process. Vanadium is found in many bunker oils, but the vanadium content varies greatly depending on the region where crude oil is produced. However, vanadium reacts with oxygen during combustion to oxidize to vanadium pentoxide (V ₂ O ₅ ), and to vanadium trioxide (V ₂ O ₃ ) when operated with extremely low excess air.

When such vanadium oxide remains in the furnace such as a boiler, it not only promotes the generation of sulfur trioxide due to the catalytic action, but also the vanadium oxide easily combines with ash and accumulates in the furnace to become a major cause of corrosion of the inner wall of the boiler. It is known. On the other hand, iron oxide (Fe ₂ O ₃ ) generated by the corrosion in the furnace is also known to play a role of the catalyst for the generation of sulfur trioxide, it will be very important to prevent the accumulation of vanadium oxide in the furnace. Sulfur trioxide, which generates sulfuric acid mist, the main cause of visible white smoke generation, is generated by flame during combustion, but more than 50% is known to be caused by conversion of sulfur dioxide to sulfur trioxide by a catalyst (especially vanadium).

Conventionally, in order to remove such vanadium oxide, a method of injecting magnesium oxide into the exhaust gas after combustion as an absorbent for preventing the generation of sulfur trioxide has been proposed as a method of removing sulfur trioxide. There was a problem that it is difficult to ensure sufficient reaction time to supply the oxide in the form of a powder.

In order to solve the above problems, an object of the present invention is to provide a magnesium slurry for preventing the accumulation of vanadium oxide in the boiler as a method for reducing the generation of sulfur trioxide and a method of injecting the same into a fuel.

It is also an object of the present invention to provide an emulsifier that improves the diffusivity and dispersibility of a fuel so that the fuel is in full contact with oxygen in the air to achieve complete combustion.

In addition, the present invention is to provide a method for lowering the temperature of the boiler outlet, as a method for improving the thermal efficiency of the boiler.

In order to achieve the above object, the present invention, in the boiler thermal efficiency improvement and / or visible white smoke removal method, (a) a magnesium slurry containing a magnesium compound and a hydrocarbon-based solvent in the boiler 200 burners (216a, 216b, 216c) , 216d) to the fuel supply pipe 210 for supplying fuel; And (b) injecting an emulsifier comprising a hydrocarbon solvent, water, and a surfactant into the front of the burners (216a, 216b, 216c, 216d) to improve boiler thermal efficiency and / or remove visible white smoke. do.

In addition, the present invention is a magnesium slurry used in boiler thermal efficiency improvement and / or visible white smoke removal method, 50 to 81% by weight magnesium compound; 15-40% by weight of a hydrocarbon solvent including one or more of gasoline, kerosene, mineral oil, diesel, normal paraffin, isoparaffin, heavy oil and thinner; 2-4% by weight of synthetic ester lubricant additives; And it provides a magnesium slurry comprising 2 to 6% by weight naphtha.

In addition, the present invention is an emulsifier used in the boiler thermal efficiency improvement and / or visible white smoke removal method, 40 to 60% by weight of one of gasoline, kerosene, mineral oil, diesel oil, normal paraffin, isoparaffin, heavy oil and thinner Hydrocarbon solvents containing the above; 10 to 20 weight percent nonylphenol ethoxylate; 10-20% by weight of hydroethyl imidazoline; 1 to 5 weight percent sulfonate surfactant; 1 to 5% by weight of an amide based surfactant; And 1 to 10% by weight of water.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In order to prevent the generation of visible white smoke, the main content of the present invention is to add a magnesium slurry and an emulsifier for improving combustion of fuel.

The magnesium slurry according to the present invention is characterized by adding a small amount of a lubricant additive as a main component of a hydrocarbon-based solvent such as a magnesium compound and a mineral oil (Gas Oil).

The magnesium compound uses magnesium oxide (MgO), a compound of magnesium oxide and aluminum oxide (MgO-Al ₂ O ₃ ), and the like. Meanwhile, the magnesium slurry is added to the fuel and then injected into the boiler together with the fuel. In order to prevent wear of the burner nozzle, the particles of the magnesium compound are preferably spherical. However, in the practice of the present invention, considering the cost and ease of acquisition of materials, it is possible to use a magnesium compound having a rough surface, and in some cases, mixing a magnesium compound processed into a spherical form and a magnesium surface having a rough surface may be mixed. It is possible.

As the hydrocarbon solvent, gasoline, kerosene, mineral oil, gas oil, normal paraffin, isoparaffin, heavy oil, thinner and the like can be used. Since the magnesium slurry is directly added to heavy oil as fuel, as described below, it is preferable to have the same or similar chemical structure and average molecular weight as heavy oil. In consideration of the characteristics of the solvent, preferably, mineral oil, which is an intermediate fraction between kerosene and heavy oil, is used. .

Synthetic esters may be used as lubricant additives. Lubricating additives make the mixing of magnesium compounds and hydrocarbon solvents easier, and not only polyhydric alcohol esters such as glycerol monooleate, esters of C ₁ -C ₅ monohydric alcohols and polybasic acids, but also dimerized carboxylic acids. It is also possible to use C ₂ -C ₅₀ carboxylic acid series such as esters. On the other hand, when using mineral oil as a solvent, it is also possible to use penta ellis little monooleate or normal decyl phthalate.

Meanwhile, the magnesium slurry may further include Naphtha as a solvent for better dissolving magnesium oxide, including some of either Heavy Naphtha or Hydrotreated Naphtha. It is also possible.

The composition of the magnesium slurry according to a preferred embodiment of the present invention is shown in Table 1.

chemical substance weight% Magnesium Oxide 50-81 Gas Oil 15-40 Lubricity additives 2-4 Heavy Naphtha 1-3 Hydrotreated Naphtha 1-3

Magnesium slurry according to the present invention has the following effects.

First, vanadium pentoxide (V ₂ O ₅ ) mainly generated during the combustion process is converted into a vanadium compound having a high melting point to prevent accumulation in the boiler to prevent generation of sulfur trioxide due to the catalytic reaction.

The melting point of vanadium pentoxide (V ₂ O ₅ ) is about 600 ° C., which is easily melted in the boiler and attached to the inner wall of the boiler, causing scale generation. This vanadium pentoxide (V ₂ O ₅ ), as described above, not only catalyzes the generation of sulfur trioxide, but also oxidizes the boiler outer wall. On the other hand, vanadium trioxide (V ₂ O ₃ ) not only has a low production rate but also has a low melting point of about 1,950 ° C., so there is little fear of accumulation in the boiler.

However, when the magnesium compound is added during the combustion process, vanadium pentoxide (V ₂ O ₅ ) is generated as 3MgO · V ₂ O ₅ having a melting point of about 1,180 ° C. by the reaction of Chemical Formula 6 and discharged to the outside of the boiler together with the exhaust gas. The accumulation of vanadium pentoxide (V ₂ O ₅ ) in the boiler is prevented.

As a result, the amount of sulfur trioxide generated during the combustion process is reduced, thereby reducing the amount of sulfur trioxide delivered to the low temperature portion of the boiler outlet side.

On the other hand, magnesium slurry has another effect as follows.

On the other hand, the change in the acid dew point (the temperature at which the acid gas is combined with water vapor) according to the concentration of sulfur trioxide is shown in Table 2, the temperature of the acid dew point is lowered as the sulfur trioxide concentration in the flue gas is lowered.

SO ₃ concentration (ppm) 0.1 0.2 0.5 One 2 5 10 20 50 70 Sun dew point (℃) 102 105 112 117 122 128 133 138 147 150

In addition, when looking at the conversion rate of sulfur trioxide to sulfuric acid (H ₂ SO ₄ ) according to the temperature shown in Figure 2 it can be seen that the lower the temperature, the higher the conversion rate to sulfuric acid.

1 is a graph showing the conversion rate of sulfur trioxide to sulfuric acid with temperature in a state where the exhaust gas moisture ratio is 8%.

Therefore, as described below, sulfur trioxide can be further removed by converting sulfur trioxide into sulfuric acid by lowering the average temperature of the air preheater cold end area, and then reacting the magnesium in the magnesium slurry with the formula (7).

Next, the emulsifier according to the present invention is a water-in-oil form in which a small amount of water is added to a hydrocarbon-based solvent such as mineral oil, and nonylphenol ethoxylate and hydroethyl imide as a dispersing emulsifier. It is used as a main raw material, and a small amount of sulfonate surfactant such as Alkylbenzene Sulfonic Acid Sodium Salt or amide-based surfactant such as alkanolamide is added as needed. It is characterized by.

The emulsifier enables complete combustion of the fuel by emulsifying and stabilizing the fuel, thereby reducing excess air during combustion.

Table 3 shows the composition ratios of the emulsifiers according to the preferred embodiment of the present invention.

chemical substance weight% Gas Oil 40-60 Nonylphenol Ethoxylate 10-20 Hydroethyl imidazoline 10-20 Water 1-10 Alkylbenzene Sulfonic Acid Sodium Salt 1-5 Alkanolamide 1-5

A method of adding a magnesium slurry and an emulsifier to a fuel according to the present invention is as follows.

FIG. 2 is a diagram illustrating a combustion system in which a magnesium slurry and an emulsifier are added to a combustion system in a method of improving boiler thermal efficiency and / or removing visible white smoke in a preferred embodiment of the present invention.

Briefly describing the boiler combustion system, the heavy oil supplied through the fuel supply pipe 219 is supplied to the first burner (216a), the second burner (216b), the third burner (216c), and the fourth burner (216d). In addition, the mixture is combusted with combustion air supplied through the combustion air supply pipe 218. However, the number of burners 216a, 216b, 216c, and 216d may be provided as one to three or five or more in addition to four as shown in FIG.

Combustion air supplied to the boiler 200 through the combustion air supply pipe 218 is first preheated in the steam air preheater (Steam Air Heater 205), and then in the air preheater (Air Heater, A / H: 204). Secondary preheating through heat exchange with the exhaust gases emitted after combustion.

On the other hand, the flue gas discharged after the combustion from the boiler 200 passes through an air preheater 204 after the removal of nitrogen oxides (NOx) through a denitrification apparatus (Selective Catalytic Reduction, SCR: 202) and an electrostatic precipitator. (Electrostatic Precipitator, EP: 206) to the desulfurization plant (Flue Gas Desulfurization, FGD: 210). At this time, ammonia delivered from the ammonia storage / injection facility 114 is injected into the front of the denitrification apparatus SCR to remove nitrogen oxides from the exhaust gas.

The exhaust gas delivered to the desulfurization facility 110 and the exhaust gas delivered to the stack (Stack: 212) after the desulfurization treatment are heat exchanged in a gas-gas heater (GGH: 208a, 208b), which is a stack 212. This is to improve the diffusibility of the exhaust gas by increasing the temperature of the exhaust gas delivered to).

In this process, the magnesium slurry and emulsifier according to the present invention are added directly to the heavy oil as fuel.

The magnesium slurry stored in the magnesium slurry reservoir 220 may be supplied to the burners 216a, 216b, 216c, and 216d through the top burner supply pipe 224 or the entire burner supply pipe 226 by the magnesium slurry supply pump 222. Can be.

However, in the practice of the present invention, the magnesium slurry is preferably supplied to the burner located at the top of the boiler 200 through the uppermost burner supply pipe 224, and to the fourth burner 216d in FIG. Because the burner (216a, 216b, 216c, 216d) is located in the boiler 200 is called a water wall (Water Wall) is provided with a heat exchanger for heating most of the boiler feed water, the inner wall of the boiler 200 after magnesium burned This is because the heat exchange to the boiler feed water can be disturbed if it is attached.

However, in order to more reliably remove the sulfur oxide contained in the heavy oil in the practice of the present invention, the magnesium slurry can be supplied not only to the fourth burner 216d at the top but also to the third burner 216c or the second burner 216b. have. Also, although not shown in FIG. 2, the magnesium slurry supply pipe is connected to the magnesium slurry supply pump 222, the second burner 216b, and the third burner 216c, respectively, so that the fourth burner may be used during the low power operation of the boiler 200. When the 216d is not operated, the magnesium slurry is supplied to the third burner 216c and the second burner 216b when the fourth burner 216d and the third burner 216c are not operated.

At this time, the supply amount of the magnesium slurry is preferably 0.03 to 0.07% based on the weight of the total heavy oil supplied to the boiler 200. That is, 0.30 to 0.70 kg of magnesium slurry per ton of heavy oil is supplied to the burners 216a, 216b, 216c, and 216d using the magnesium slurry supply pump 222.

As described above, magnesium not only prevents vanadium pentoxide (V ₂ O ₅ ) from accumulating in the boiler 200, but also suppresses the generation of sulfur trioxide, as well as the air preheater 204 and the gas-gas heaters 208a and 208b. It neutralizes sulfuric acid produced from cold end and prevents corrosion of equipment.

On the other hand, the emulsifier according to the present invention stored in the emulsifier reservoir 230 is continuously introduced into the heavy oil as fuel by the emulsifier supply pump 232. As shown in Fig. 2, the emulsifier is supplied at the front end of the magnesium slurry feed position and is supplied to the entire burners 216a, 216b, 216c, and 216d.

Next, a method of lowering the average temperature of the air preheater 204 will be described as a method for converting sulfur trioxide in the exhaust gas into sulfuric acid as described above.

Typically, the combustion air supplied to the boiler is heated to about 100 ° C. in the steam air preheater 205 and again heated to the air preheater 204 to rise to about 270 ° C. and then supplied to the boiler 200.

However, referring to FIG. 1 as described above, the conversion rate of sulfur trioxide to sulfuric acid with temperature decreases rapidly as the temperature increases. Therefore, it is desirable to lower the temperature of the exhaust gas.

In this way, the amount of steam supplied to the steam air preheater 205 is reduced to lower the temperature of the combustion air passing through the steam air preheater 205 to about 50 to 60 ° C. Then, the temperature of the exhaust gas in the heat exchange process between the combustion air and the exhaust gas in the air preheater 204 is lower than when operating the steam air preheater 205.

In other words, through the heat exchange between the combustion air and the exhaust gas, the temperature of the exhaust gas is lowered from about 160 ° C. to about 120 ° C., which is a temperature obtained through a conventional process, thereby increasing the rate of conversion of sulfur trioxide to sulfuric acid. Magnesium supplied in the slurry is converted to magnesium sulfite (MgSO ₄ ) by reaction with hydrated magnesium hydroxide (Mg (OH) ₂ ).

Combustion test results obtained when the magnesium slurry and emulsifier according to the present invention described above were added to the heavy oil introduced into the boiler and the temperature of the combustion air passed through the steam air preheater 205 was about 50 ° C. Compared with Table 4 below. On the other hand, the test results were derived from the Ulsan Power Plant No. 6 of Dongseo Power Co., Ltd., which is a 400 MW power plant.

The composition of the magnesium slurry added to the fuel was 70.0 wt% of magnesium oxide, 25.0 wt% of mineral oil, 2.0 wt% of the lubricity additive, and 3.0 wt% of the heavy naphtha and the hydrophobic naphtha. 216d) only, and the amount was adjusted to 0.50 kg per tonne of total heavy oil supplied to the burners (216a, 216b, 216c, 216d).

The composition of the emulsifier is 60.0% by weight of mineral oil, 12.5% by weight of nonylphenol ethoxylate, 12.5% by weight of hydroethyl imidazoline, 5.0% by weight of other alkylbenzenesulfonate sodium salt, 5.0% by weight of alkanolamide. The water was brought to 5% by weight and 0.35 kg per tonne of total heavy oil supplied to the burners (216a, 216b, 216c, 216d).

Measuring position Measures unit Before improvement (conventional) After improvement (invention) Air preheater inlet (A / H INLET) SO ₂ ppm 1,347 1,346 SO ₃ ppm 48 10 NOx ppm 209 231 CO ppm 2.1 88 O ₂ ppm 1.0 0.8 Electrostatic precipitator outlet (EP OUTLET) SO ₂ ppm 1,345 1,345 SO ₃ ppm 45 0.7 SOx ppm 1,390 1,345.7 NOx ppm 201 227 CO ppm 1.0 77.3 O ₂ ppm 3.4 3.3 GGH Washing Water pH - 0.73 2.9 gypsum water - 96.3 96.4 FGD Slurry pH - 5.44 - EP ASH Unburned carbon wt% 70.4 52.5 pH - 2.5 4.3 STACK white lead - Occur Does not occur Wastewater Total nitrogen mg / l 39 55 COD mg / l 42 55

As shown in Table 4, when the magnesium slurry and the emulsifier according to the present invention were added, the concentration of sulfur trioxide at the inlet of the air preheater 204 and the outlet of the electrostatic precipitator 206 was very low. In addition, the pH of the washing water of the gas-gas heaters 108a and 108b was increased. In addition, not only the pH of ash collected in the electrostatic precipitator 206 is increased, but the amount of unburned carbon is also reduced.

These test results were the same in the tests of Units 4 and 5 of the Ulsan Power Plant, and the electrostatic precipitator was added to the magnesium slurry and emulsifier according to the present invention to the Ulsan Power Plant Units 4, 5, and 6 (206) The concentration of sulfur trioxide in the off-gas measured at the outlet is shown in Table 5.

division Unit 4 Unit 5 Unit 6 Before improvement After improvement Before improvement After improvement Before improvement After improvement SO ₃ concentration (ppm) 17.47 1.3 17.15 0.4 36.7 0.35

Meanwhile, in the practice of the present invention, as shown in FIG. 2, a part of the ammonia supplied from the mixer 256 of the ammonia storage / injection facility 214 is added to the ammonia supply pipe 260 by the sulfur trioxide further removal device 240. Supply to the front of the electrostatic precipitator 206 through helps to remove additional sulfur trioxide.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

As described above, according to the present invention, sulfur trioxide contained in the exhaust gas after boiler combustion can be effectively removed. In particular, the supply of the magnesium compound into the boiler in a powder state is supplied with the fuel in a slurry state so that the magnesium compound is dispersed together with the combustion gas while the fuel is burned, thereby effectively reacting with the vanadium oxide. Accordingly, there is an effect of preventing the visible white smoke phenomenon appearing in the exhaust gas discharged through the stack.

In addition, according to the present invention, by preventing the accumulation of vanadium compounds in the furnace, corrosion of the inner wall of the boiler is prevented, and the pH of the electrostatic precipitator, GGH, and the like is increased to prevent corrosion of the equipment by the strong acidic material.

In addition, according to the present invention, since the fuel is emulsified by the injection of the emulsifier to enable complete combustion, there is an effect of improving combustion.

In addition, according to the present invention, by lowering the temperature of the exhaust gas that has passed through the air preheater, sulfur trioxide contained in the exhaust gas is easily hydrated with sulfuric acid, and thus it is possible not only to further remove sulfur oxides, but also to lower the boiler outlet temperature. The overall thermal efficiency of the boiler rises by about 1.12%.

1 is a graph showing the conversion rate of sulfur trioxide to sulfuric acid with temperature in a state where the exhaust gas moisture ratio is 8%.

FIG. 2 is a view illustrating a method of adding a magnesium slurry and an emulsifier to a combustion system in a combustion system in a method of improving boiler thermal efficiency and / or removing visible white smoke in a preferred embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

200: boiler 202: denitrification apparatus (SCR)

204: air preheater 205: steam air preheater

206: electrostatic precipitator (EP) 208a, 208b: gas-gas heater

210: desulfurization plant (FGD) 212: stack

214: Ammonia Storage / Injection Facility

216a, 216b, 216c, 216d: 1st, 2, 3, 4 burners

218: fuel supply pipe 219: preheating air supply pipe

220: magnesium slurry reservoir 222: magnesium slurry feed pump

224: top burner supply pipe 230: emulsifier reservoir

232: emulsifier supply pump 240: sulfur trioxide further removal device

Claims (20)

In the method of improving boiler thermal efficiency and / or removing visible white smoke, (a) injecting a magnesium slurry including a magnesium compound and a hydrocarbon solvent into a fuel supply pipe 210 for supplying fuel to burners 216a, 216b, 216c, and 216d of the boiler 200; And (b) a step of injecting an emulsifier including a hydrocarbon solvent, water, and a surfactant into the front ends of the burners 216a, 216b, 216c, and 216d. Boiler thermal efficiency improvement and / or visible white smoke removal method comprising a. The method of claim 1, In the process (a), the magnesium slurry is supplied to only the top burner in operation among the burners 216a, 216b, 216c, and 216d of the boiler 200, and thus improving boiler thermal efficiency and / or visible white smoke removal method. . The method of claim 2, The boiler thermal efficiency and / or visible white smoke removal method, (c) controlling the amount of steam supplied to the steam air preheater 205 so that the temperature of the combustion air passing through the steam air preheater 205 is 50 to 60 ° C. Boiler thermal efficiency improvement and / or visible white smoke removal method, characterized in that further comprising lowering the temperature of the exhaust gas discharged after combustion in the boiler (200). The method according to any one of claims 1 to 3, The boiler thermal efficiency and / or visible white smoke removal method, (d) supplying ammonia supplied from the ammonia storage / injection facility 214 of the boiler 200 to the front of the electrostatic precipitator 106; Boiler thermal efficiency improvement and / or visible white smoke removal method further comprising. The method according to any one of claims 1 to 3, The magnesium slurry, 50 to 81 weight percent magnesium compound; 15-40% by weight of a hydrocarbon solvent including one or more of gasoline, kerosene, mineral oil, diesel, normal paraffin, isoparaffin, heavy oil and thinner; 2-4% by weight of synthetic ester lubricant additives; And 2-6 wt% naphtha Boiler thermal efficiency improvement and / or visible white smoke removal method comprising a. The method of claim 5, wherein The hydrocarbon solvent is a mineral oil (Gas Oil) thermal efficiency improvement and / or visible white smoke removal method of the boiler. The method of claim 6, The synthetic ester-based lubricity additive is any one of penta ellis little monooleate and normal decyl phthalate, the boiler thermal efficiency improvement and / or visible white smoke removal method. The method of claim 5, wherein The naphtha comprises a heavy naphtha and hydrotrified naphtha, the boiler thermal efficiency improvement and / or visible white smoke removal method. The method according to any one of claims 1 to 3, The emulsifier is, 40 to 60% by weight of a hydrocarbon solvent including one or more of gasoline, kerosene, mineral oil, diesel, normal paraffin, isoparaffin, heavy oil and thinner; 10 to 20 weight percent nonylphenol ethoxylate; 10-20% by weight of hydroethyl imidazoline; 1 to 5 weight percent sulfonate surfactant; 1 to 5% by weight of an amide based surfactant; And 1 to 10% by weight of water Boiler thermal efficiency improvement and / or visible white smoke removal method comprising a. The method of claim 9, The hydrocarbon solvent is a mineral oil, characterized in that the boiler thermal efficiency improvement and / or visible white lead removal method. The method of claim 9, The sulfonate surfactant is sodium benzene sulfonate, characterized in that the boiler thermal efficiency improvement and / or visible white smoke removal method. The method of claim 9, The amide-based surfactant is alkanol amide, the boiler thermal efficiency improvement and / or visible white smoke removal method. Magnesium slurry used in boiler thermal efficiency improvement and / or visible white smoke removal method, 50 to 81 weight percent magnesium compound; 15-40% by weight of a hydrocarbon solvent including one or more of gasoline, kerosene, mineral oil, diesel, normal paraffin, isoparaffin, heavy oil and thinner; 2-4% by weight of synthetic ester lubricant additives; And 2-6 wt% naphtha Magnesium slurry used in boiler thermal efficiency improvement and / or visible white smoke removal method comprising a. The method of claim 13, Magnesium slurry used in the boiler thermal efficiency improvement and / or visible white smoke removal method, characterized in that the hydrocarbon solvent is mineral oil. The method of claim 14, Magnesium slurry used in the boiler thermal efficiency improvement and / or visible white smoke removal method, characterized in that the synthetic ester-based lubricity additive is any one of penta ellis little monooleate and normal decyl phthalate. The method according to any one of claims 13 to 15, Magnesium slurry used in the boiler thermal efficiency improvement and / or visible white smoke removal method, characterized in that the naphtha comprises a heavy naphtha and hydrotrified naphtha. As an emulsifier used in boiler thermal efficiency improvement and / or visible white smoke removal method, 40 to 60% by weight of a hydrocarbon solvent including one or more of gasoline, kerosene, mineral oil, diesel, normal paraffin, isoparaffin, heavy oil and thinner; 10 to 20 weight percent nonylphenol ethoxylate; 10-20% by weight of hydroethyl imidazoline; 1 to 5 weight percent sulfonate surfactant; 1 to 5% by weight of an amide based surfactant; And 1 to 10% by weight of water Emulsifiers used in boiler thermal efficiency improvement and / or visible white smoke removal method comprising a. The method of claim 17, Emulsifiers used in boiler thermal efficiency improvement and / or visible white smoke removal method, characterized in that the hydrocarbon solvent is mineral oil. The method of claim 17 or 18, The sulfonate surfactant is emulsifier used in boiler thermal efficiency improvement and / or visible white smoke removal method, characterized in that the sodium alkylbenzene sulfonate. The method of claim 17 or 18, The amide-based surfactant is an emulsifier used in the boiler thermal efficiency improvement and / or visible white smoke removal method, characterized in that the alkanolamide.