WO2003066198A1 - Additive for exhaust gas, method of manufacturing the additive, and method for power generation using the additive - Google Patents

Abstract

An additive for exhaust gas capable of efficiently and safely neutralizing and removing the exhaust gas of fossil fuel, for example, SOx produced by the use of the fuel containing sulfur content in a boiler by adding the additive formed with the solution of magnesium hydrogencarbonate or calcium hydrogencarbonate to the exhaust gas of the fossil fuel into the fuel, combustion air, combustion equipment, and a flue on the downstream side of the combustion equipment.

Description

 Description Additive for combustion gas, method for producing the same, and power generation method using the additive

 The present invention relates to an additive, a method for producing the additive, and a power generation method as one embodiment of a method for using the additive. Background art

 At a thermal power plant, fossil fuels such as coal, crude oil, heavy oil, and tar are burned in a boiler together with air to obtain pressurized steam, and the steam is used to turn a turbine to generate electricity.

Since these fossil fuels usually contain sulfur, the exhaust gas will contain sulfur _oxides (SO _x ). Then, the exhaust gas containing sulfur oxides is cooled, reaches the dew point, and generates sulfuric acid H ₂ SO ₄ . On the other hand, the flue of exhaust gas is usually provided with an air preheater, and when the exhaust gas containing sulfuric acid passes through the air preheater, the air preheater is corroded and blocked. As a countermeasure, it is common to maintain the temperature of exhaust gas so that the dew point of SO ₃ is not reached.

 In addition, since fossil fuels contain a large amount of non-flammable carbon such as residual carbon and fixed carbon, dust is easily generated in exhaust gas. Therefore, it is desired to promote the combustion of fossil fuels and suppress the flame-retardant carbon which is a main component of the dust.

 In addition, fossil fuels contain ash, especially vanadium, sodium, etc., which can cause problems such as poiling at high temperatures. It is desired to suppress such high-temperature damages of the ash.

MgO, Te Bantsu an inorganic material such as CaO additives to an oil slurry scratch was added to the fuel oil to suppress the catalytic activity of the vanadium is so ₃ synthesizing catalyst contained in the heavy oil or the like, thereto, sulfur acid There is also known a method for suppressing the generation of effluents. The amount of so ₃ generated

Although is suppressed to about 50% are still many S0 _3.

By adding such additives, the unburned matter, which is the main component of dust, is also reduced. Can be done. However, when a large amount of additive is added, additional components accumulate on the heat transfer section of the boiler, for example, on the wall of the heat exchanger, and the balance of heat transfer is disrupted, making it difficult to operate the boiler.

 Additives include oil-soluble, colloidal, or caneous or magnesium acetates or nitrates. These additives are expensive and cannot be used in large quantities.

 As a method of positively neutralizing in the middle of the flue, there is a method of injecting powder of calcium hydroxide, calcium carbonate, magnesium oxide, magnesium hydroxide, and water slurry. Most of the particle diameters of calcium hydroxide and the like in the water slurry are around 50 μπι to 15θm, and many particles of several hundred μπι class are contained therein. Because of the large particle size, the reactivity is poor. In particular, when a large amount of additive is added, a large amount of the dust accumulates at the bottom of the flue at the injection point, and white dust falls, which requires time and labor to remove the dust and increases the maintenance cost. The addition is difficult. Because of the calorie and poor reactivity, the effect of reducing sulfuric acid mist fluttering observed as white smoke is hardly noticeable.

As an active ingredient of the additive, ammonia, reactivity widely used from a very good electrostatic precipitator dust collecting efficiency increases with S0 ₃ and H ₂ S0 ₄ by corrosion. However, when ammonia is added, acidic ammonium sulfate and sulfite are produced. Ammonium sulfate and sulfite are deposited on the electrostatic precipitator and adhere to the discharge electrode. As a result, the voltage value increases and a hunting phenomenon appears, which causes a failure due to poor charging, or flows out of the chimney, resulting in acid dust. Due to the improper charging, the dust regulation value for regulating dust, which causes air pollution, may temporarily be exceeded.

In addition, ammonia has many regulations and regulations, and has many issues in handling, maintenance and safety. For example, injection of ammonia requires storage and vaporization equipment for liquid ammonia, and there are legally regulated high-pressure gases, toxic substances, occupational safety, and combustible gas. Caustic soda and sodium carbonate aqueous solutions are also used as additives, and these aqueous solutions have performance comparable to ammonia. However, the cost per mole is higher due to the higher molecular weight compared to ammonia. Also, the air heater, that is, the revised paper (regulation MM) If these aqueous solutions are added before the air preheater, the combustion air and exhaust gas exchange heat with each other, and a large amount of sodium salt, which causes high-temperature damage, is mixed into the combustion air and enters the combustion chamber. . The present invention is to efficiently and safely remove sulfur oxides (so _x ), particularly so ₃ , in exhaust gas generated by burning sulfur-containing fuel in a flue gas of a fuel such as a poiler. It is intended to neutralize and remove.

The air preheater installed in the flue of the combustion exhaust gas, electric precipitator, Oite the flue side wall or the like, the exhaust gas is cooled, prevents the H ₂ SO ₄ reaches the dew point, H ₂ S0 _The purpose is to suppress the corrosion and obstruction failures caused by ₄ .

 Another object of the present invention is to prevent dust accumulated in a flue or the like from being discharged as a lump containing a large amount of sulfuric acid having a low pH due to load fluctuations, etc., and to suppress the generation of acid fallen dust that causes environmental degradation. .

 It is also intended to reduce the failure of charging of the electrostatic precipitator, reduce the amount of ammonia added, and reduce the amount of ammonia added.

 Another objective is to efficiently control high-temperature corrosion caused by vanadium and sodium contained in fuel.

 It is another object of the present invention to promote the combustion of unburned carbon components and suppress the generation of dust. Still another object of the present invention is to positively lower the exhaust gas temperature and increase the boiler efficiency.

 A further object of the present invention is to increase the operation rate and efficiency of a boiler and the like and to enable stable operation for a long period of time. Disclosure of the invention

 The present invention determines at least one of the above objects.

The present inventor has an aqueous solution containing a water Maguneshiumui匕合compound or Karushiumu compound pressurized by mixed gas containing carbon dioxide or carbon dioxide and then by heating the aqueous solution, the so ₃ It has been found that an inexpensive additive that can be efficiently and safely neutralized can be obtained. In addition, in the above-mentioned additives, it was found that the active ingredient was contained as extremely fine particles, and it was also found that the additives had extremely excellent functions. In addition, they have found that fossil fuel combustion exhaust gas can be used as a gas containing carbon dioxide in obtaining the above additives.

 In addition, in thermal power generation, the above-mentioned additives are manufactured using combustion exhaust gas, and the resulting additive is used as an additive for combustion exhaust gas of a combustion device, thereby achieving high efficiency, and at the same time, high efficiency, It has been found that it is possible to provide an environmentally friendly power generation method because it can reduce emissions of sulfur and sulfur oxides and dust.

 According to a first aspect of the present invention, there is provided an additive comprising an aqueous solution of magnesium bicarbonate or calcium bicarbonate, wherein the concentration of the magnesium component in the additive is 0.1% to 3% by weight in terms of MgO. 0% by weight, or the concentration of calcium component in the additive is 0.1% to 30% by weight in terms of CaO. An additive for combustion gases is provided. .

 In the first aspect of the present invention, the additive is such that at least a part of magnesium bicarbonate or calcium bicarbonate is dissolved in the aqueous solution, and at least a part of magnesium hydroxide or calcium hydroxycarbonate is fine crystals. Alternatively, it may be suspended in the aqueous solution. In this case, it is preferable that 90% by weight or more of the fine crystals have a particle size of 1 μπι or less.

 In a second aspect of the present invention, a step of introducing exhaust gas of fossil fuel into an aqueous liquid containing a magnesium compound or a calcium compound and water, and a step of pressurizing the aqueous liquid into which the exhaust gas has been introduced, comprising: A step of heating the aqueous liquid to a temperature equal to or higher than the temperature of the gelich step and a step of heating the aqueous liquid to a boiling point or lower in order to volatilize and remove the carbon dioxide gel. The present invention provides a method for producing an additive comprising magnesium hydrogencarbonate or calcium hydrogencarbonate, magnesium hydroxide or calcium carbonate, and water.

In the second aspect of the present invention, the magnesium compound or the calcium compound is preferably an inorganic substance. When the aqueous liquid is pressurized, it is preferable to apply a pressure of 9.8 X 10 ⁴ Pa (1 kgfcm2) or more.

According to a third aspect of the present invention, fossil fuel is burned together with air in a combustion device, and water vapor corrected paper (91) Obtaining the gas, rotating the turbine with the steam, and generating electric power, adding the additive according to the first aspect or the additive obtained by the production method according to the second aspect to the fossil fuel Medium, in the air, inside the combustion device, a connection between the combustion device and a flue downstream of the combustion device, or a step of adding to the flue. Provided.

 In the third aspect of the present invention, the additive can be added near an outlet of an echo unit in the combustion device or near an outlet of an air preheater in the flue. In a fourth aspect of the present invention, a step of burning fossil fuel together with air in a combustion device to obtain water vapor and obtaining exhaust gas, a step of rotating a turbine with the steam to generate electric power, A step of introducing at least a part of the aqueous liquid containing a magnesium compound or a potassium compound and water, and pressurizing the aqueous liquid into which the exhaust gas has been introduced, and converting the diacid carbon in the exhaust gas into an aqueous liquid. Heating the aqueous liquid above the temperature of the gelling step and below the boiling point of the aqueous liquid, in order to volatilize and remove the carbon dioxide gel. Obtaining an additive comprising hydrogen calcium, magnesium hydroxycarbonate or calcium hydroxycarbonate, and water; and adding the additive in the fossil fuel; in the air; Internal serial combustion apparatus, the connection portion of the downstream flue of the combustion apparatus and the combustion apparatus, also, the power generation method characterized by including the step of adding to the flue is provided. In the fourth aspect of the present invention, the concentration of the magnesium component in the additive is 0.1% by weight to 30% by weight in terms of MgO, or the concentration of the calcium component in the additive is The concentration is 0.1 weight in terms of CaO. /. It is preferably about 30% by weight.

Further, at least a part of magnesium bicarbonate or calcium bicarbonate is dissolved in the aqueous liquid, and at least a part of magnesium hydroxycarbonate or hydrocalcium carbonate is fine crystals in the aqueous liquid. It may be floating in the water. In this case, it is preferable that 90% by weight or more of the fine crystals have a particle size of 1 zm or less. Brief description of the drawings Corrected paper (! Figure 1 is a schematic diagram of a boiler and a flue in a power plant. BEST MODE FOR CARRYING OUT THE INVENTION

 According to a first aspect of the present invention, there is provided a fuel gas additive for a fuel device, comprising an aqueous solution of magnesium hydrogen carbonate or calcium hydrogen carbonate.

 When the additive according to the present embodiment is composed of an aqueous solution of magnesium hydrogen carbonate, the concentration of the magnesium component in the added carohydrate is 0.1% by weight to 30% by weight in terms of MgO. When the additive is an aqueous calcium hydrogen carbonate solution, the concentration of the calcium component in the additive is 0.1% by weight to 30% by weight in terms of CaO.

 If the amount of the active ingredient in the additive is in the above range (1), a large amount of the additive is required, and as a result, there are few problems such as the equipment such as the tank and the transfer pump becoming too large, which increases the equipment cost. preferable. Further, when the content is within the above range, the active ingredient can be stably dissolved even at a low temperature in winter, so that it is preferable. On the other hand, if the amount of water in the additive is too large, it will affect the temperature and efficiency of the exhaust gas when added to exhaust gas, and there is evidence that water will accumulate at the point of addition, and such water will burn It is not preferable because it causes 鲭 of the equipment and flue.

 Further, in the additive according to the aspect, at least a part of magnesium hydrogencarbonate or calcium hydrogencarbonate may be dissolved in the aqueous solution, and at least a part of magnesium hydroxide or calcium carbonate is fine crystals. It may be floating in an aqueous solution.

Incidentally, the fine 9 0 wt% or more of the crystal grain size 1 beta m or less it is rather preferable, 0. 1 _mu It is further preferred πα or less. This is because the smaller the particle size, the larger the surface area, so that the effect as an additive is improved.

 The additive according to this embodiment may contain other components such as impurities in addition to the above components, and may contain, for example, silica and the like.

In a second aspect of the present invention, there is provided a method for producing an additive, comprising magnesium hydrogencarbonate or calcium hydrogencarbonate, magnesium hydroxycarbonate or calcium hydroxycarbonate, and water. Corrected use 11 (Regulation i¾91) The production method according to this aspect includes a step of introducing an exhaust gas of fossil fuel into an aqueous liquid containing a magnesium compound or a calcium compound and water, and a step of pressurizing the aqueous liquid into which the exhaust gas has been introduced, thereby reducing carbon dioxide in the exhaust gas. Gelling in an aqueous liquid; and heating the aqueous liquid to a temperature equal to or higher than the temperature of the Gelich step and equal to or lower than the boiling point of the aqueous liquid in order to volatilize and remove the carbon dioxide gel.

Preferable examples of the magnesium compound include inorganic magnesium compounds. As the inorganic magnesium compound, _{e.g., MgO, Mg (OH) 2} , MgCO 3, MgO, Mg (OH) 2, MgC0 3 can be mentioned, preferably may be mentioned MgO.

Further, as the calcium compound, an inorganic calcium compound can be preferably mentioned. Examples of the inorganic calcium compound include CaO, Ca (OH) ₂ and CaCOs, and preferably CaO.

 Fossil fuels include fossil fuels containing carbon without particular limitation.Examples include petroleum, crude oil, naphtha, light oil, kerosene, heavy oil, aspanolet, orinoco tar, orimarsion, oil shell, oil sands, oil coatas, Examples include blast furnace gas, liquefied natural gas (LNG), and liquefied petroleum gas (LPG). In particular, the present invention can be suitably applied to fossil fuels having a relatively high sulfur content. According to the method for producing an additive according to the present invention, fossil fuel exhaust gas is introduced into an aqueous liquid containing a magnesium compound or calcium conjugate and water, and then the aqueous liquid is pressurized. By pressurizing the aqueous liquid, carbon dioxide in the exhaust gas is gelled by the aqueous liquid. At this time, it is considered that the magnesium compound or the calcium compound in the aqueous liquid becomes magnesium bicarbonate or calcium bicarbonate and is dissolved in the aqueous liquid.

The pressure for pressurizing ^{is, 9. 8 X 1 0 4} P a is preferably (l kg £ ¾m ²⁾ or more, more preferably _{4 9 x 1 04p a (5} kgf7cm 2) or more.

Next, this aqueous liquid is heated to a temperature equal to or higher than the temperature of the Gelich step and lower than the boiling point of the aqueous liquid to volatilize and remove the carbon dioxide gel. Through the above steps, fine crystals of magnesium magnesium hydroxycarbonate or calcium hydroxycarbonate can float in the aqueous liquid. Thus, magnesium bicarbonate or calcium bicarbonate, The active ingredient such as magnesium hydroxycarbonate or calcium hydroxycarbonate can be obtained as extremely fine particles. The superiority of the additive performance is determined by the particle size, so that a very excellent additive can be obtained by the above method. From the viewpoint of increasing the stability of the additive and improving the dispersibility of the additive in the additive, an oil, an emulsifier, or the like can be further added to the additive.

 According to a third aspect of the present invention, there is provided a power generation method which is an application example of the additive according to the first aspect and the additive obtained by the production method according to the second aspect.

 In the power generation method according to the present aspect, a step of burning fossil fuel with air in a combustion device to obtain steam, a step of turning a turbine with the steam to generate electric power, and the step of: In the air, inside the combustion device, a connection between the combustion device and a flue downstream of the combustion device, or a step of adding to the flue.

 The position where the additive is added will be described with reference to FIG. Figure 1 is a schematic diagram of a boiler and a flue in a power generator. The poiler has a furnace 1, a heater 3 for heating the furnace 1, and an echo unit 2. A fuel pipe for adding fuel and a pipe for introducing combustion air are connected to the boiler, and an oil heater for heating the fuel is disposed in the fuel pipe in advance. A burner for preheating the air is provided in the air introduction pipe. In addition, an unillustrated laser denitration apparatus for removing nitrogen oxides may be installed near the outlet of the boiler.

 A flue is formed between the exhaust gas outlet of the boiler and the chimney 7. In the flue, an air preheater 4, an electric precipitator 5 for removing dust in exhaust gas, and a wet desulfurizer 6 for spraying a desulfurizing agent are arranged in this order from upstream to downstream. Desulfurization equipment 6) The denitration equipment is installed for the purpose of improving air pollution, but it is also particularly effective in preventing acid ammonium sulfate from adhering to the air preheater 4 in the denitration equipment.

 In the present specification, the flue means a flow path of exhaust gas in a combustion device such as a boiler, and also includes a flow path inside a chimney.

In the present invention, the location where the additive is injected may be in a fuel, in combustion air, inside a combustion device such as a poiler, a connection between the combustion device and a flue downstream of the combustion device, and a flue. Can be mentioned. For example, as shown in FIG. 1, it may be added to a fuel pipe, an intake pipe for combustion air, the inside of a boiler, and the like. Also, the flue downstream of the boiler, i.e., near the boiler outlet, in front of the air preheater 4, between the air preheater 4 and the electric precipitator 5, and between the electric precipitator 5 and the desulfurizer 6 It may be added to the flue between the desulfurization unit 6 and the chimney 7, the flue inside the chimney 7, and the like. The addition site is appropriately selected according to the purpose as described later.

 According to a fourth aspect of the present invention, in a power generation method for generating electric power by burning fossil fuel, an additive is produced using exhaust gas generated by combustion of fossil fuel, while adding the additive. A power generation method for performing

 The power generation method according to this aspect includes: a step of burning a fossil fuel together with air in a combustion device to obtain water vapor and obtaining exhaust gas; a step of rotating a turbine with the steam to generate electric power; A step of introducing a part into an aqueous liquid containing a magnesium compound or a calcium compound and water, a step of pressurizing the aqueous liquid into which the exhaust gas has been introduced, and a step of gelling carbon dioxide in the exhaust gas in the aqueous liquid, In order to volatilize and remove the carbon dioxide gel, the aqueous liquid is heated to a temperature not lower than the temperature of the Gelich process and not higher than the boiling point of the aqueous liquid, and magnesium hydrogen carbonate or hydrogen carbonate is used. Obtaining an additive containing calcium and water; and adding the additive in the fossil fuel; in the air; Internal part of the combustion device, a connection between the combustion device and a flue downstream of the combustion device, or a step of adding to the flue.

 The description of fossil fuels, various compounds, combustion equipment, flue, etc. is as described in the preceding embodiment.

 Next, the amount and location of the additive according to the present invention will be described for each purpose.

To prevent corrosion and clogging by S0 ₃ air preheater, the additives, relative to 1 mol of S0 _3, in terms of MgO or CaO, the addition amount such that 0.01 mol to 5 mol, It is preferable to inject into the exhaust gas channel between the combustion device and the air preheater.

In order to suppress acid deposition, it is preferable to inject the above additive into the flue between the boiler outlet and the chimney at an addition amount of 1% by weight to 20% by weight based on the amount of dust. Good.

 In order to suppress charging failure and reduce ammonia in the electrostatic precipitator, the above additives should be added to the electric precipitator from the boiler outlet in an amount of 1 wt% to 20 wt% based on the amount of dust. It is preferred to inject into the flue between

When replacing the injection of ammonia into the electrostatic precipitator with the injection of the above-mentioned additive, the above additive is used in an amount of 1 to 20 mol per ₃ mol of S0 between the boiler outlet and the electric dust collector. It is preferred to inject into the road.

The Tanabiki suppression of white smoke, such as flue gas desulfurization apparatus, the additives, relative to sulfuric acid (converted to 1 mol of SO _3), 0. 1 mol to 2 0 moles to become such添Ka卩量However, it is preferable that the fuel be injected from the boiler outlet into the flue downstream.

 When treating the combustion exhaust gas of fossil fuels containing vanadium, sodium, or sulfur, the above additives should be added to fossil fuels in order to suppress high-temperature corrosion represented by so-called vanadium attack and high-temperature sulfidation corrosion = sulfur attack. On the other hand, converted to MgO or CaO, O.lppn! Add to the fuel or combustion air in an amount such that it becomes ~ 100 ppm, and Mg or Ca / V, M or Ca / Na, or Mg or Ca / S 1S in a weight ratio of 0.1 to 3. It is desirable to do.

S0 ₃ in the suppression occurrence of the above additives, relative to fossil fuels, with the addition amount such that the 0.1ppm~1000ppm in terms of MgO or CaO, also, Mg or Ca / V, Mg, or Ca / Na, or Mg or Ca / S force It is desirable to add to fuel or combustion air in a weight ratio of 0.1 to 3.

 In order to suppress the dust of the main component of unburned carbon, the above additives should be added to fossil fuels in an amount of O.lppm ~: LOOOppm in terms of MgO or CaO, and Mg or Ca It is desirable to add / V, Mg or Ca / Na, or Mg or Ca / S to the fuel or combustion air so that the weight ratio becomes 0.1 to 3.

 The relative amount of the above additives depends on the flow rate of the smoke in the flue. Generally, when the flow rate is high, the amount of the additive tends to increase. Also, by increasing the additive amount of the additive, the temperature of the exhaust gas can be lowered, and the boiler efficiency is improved.

Hereinafter, characteristics of the use of the additive according to the present invention will be described. 1. When additives are spouted into high-temperature exhaust gas and injected finely, fine particles are obtained compared to solids such as powders. Further, SO ₃ from the relationship of the evaporation latent heat of water condensation in the H ₂ S0 _4. Before water droplets evaporate, water droplets surface temperature low, sulfur oxides, especially since S0 ₃ is easily adsorbed dissolved, very rapid neutralization is carried out. As a result, harmless M _g S0 _4,

CaSO4 is produced.

 2. The use of additives as a neutralizing agent allows safe handling because there is no regulation of high-pressure gas and noxious substances compared to ammonia.

 3. Because it is an aqueous liquid, it can be injected more accurately than powder, and stable and accurate neutralization can be achieved.

 4. Even when the temperature of the exhaust gas is lowered, the flue is not clogged, and the boiler efficiency is improved. Example 1

MgCO ₃ was used without purification from magnesite (purity 95%), which is commercially available in northeast China, especially near Haicheng City. In industrial water, the following magnesite powder 1 0 0 mesh, in terms of MgO was added to a 1 0% by weight, then stirred to obtain a suspension of M _g C0 _3. The suspension was stirred while introducing exhaust gas into the suspension from a boiler burning heavy oil. Table 1 shows the specifications and exhaust gas composition of this boiler. In the examples, the kg ^ cm ^2, refers to 9.8xl0 ⁴ Pa.

(table 1 )

 Poiler specification and exhaust gas composition Poiler specification

 Model Natural circulation

 350 T / H

 540 ° C

Steam pressure 110kgf / cm ^z Exhaust gas composition

 CO, 11%

 1.2%

 1200ppm

so ₃ 43 ppm Then, at room temperature, a pressure of 5 kg / n ² was applied to the suspension with a compression pump at room temperature to obtain a translucent solution. Magnesium bicarbonate is produced. Subsequently, the mixture was heated to about 60 ° C. or higher to obtain an additive aqueous solution.

Thus the additive solution obtained, S0 ₃ with the addition amount shown in Table 2 as the conversion amount of MgO with respect to water washing times required by clogging due S0 ₃ of the air preheater,及Pi test piece The amount of corrosion was measured. The aqueous solution of the additive was injected into the flue between the poiler and the air preheater while applying a pressure of 5 kgffcm ^. The boiler and flue shown in Fig. 1 were used as the boiler and flue. The poiler has a furnace 1, a heater 3 for heating the furnace 1, and an echo unit 2. A flue is formed between the exhaust gas outlet of the poiler and the chimney 7. In the stack, an air preheater 4, an electric precipitator 5 for removing dust in exhaust gas, and a wet desulfurizer 6 for spraying additives are arranged in this order from upstream to downstream. . The test piece used was plain steel and had an original weight of 11.5 g. Table 2 shows the test results.

Corrected 甩 paper (Regular | ¾91) (Table 2) Clogging and pre-washing of air preheater, suppression of corrosion, and reduction of exhaust gas temperature

As seen from Table 2, by adding an additive aqueous solution containing 1 mole of the magnesium component with respect to S0 _3, an air preheater without clogging during operation for one year, it does not require a time of washing I understand. In addition, the addition of the additive aqueous solution shows that the corrosion amount due to the test piece has been reduced by nearly 93%, and it is expected that the operation rate will be improved and the life of the air preheater will be extended. Incidentally, with respect to S0 _3, by hydrogenation mosquito卩additives aqueous solution containing only 0.01 moles of magnesium components, those previously in addition had been washed about once every ^three months, the washing times throughout the year 2 It can be seen that it has been improved to only about three times and the corrosion amount by the test piece has been reduced by nearly 70%.

 Also, in Example 1 in which the additive aqueous solution was added to the flue, even when the exhaust gas temperature at the outlet of the air preheater was reduced from 160 ° C to 70 ° C, an increase in differential pressure due to clogging was observed. Did not. Thus, by reducing the temperature of the exhaust gas, the efficiency of the boiler was improved from 89% to 92%, and energy was saved. In technology fields with a high degree of perfection, such as boilers, the improvement of thermal efficiency by improving the boiler itself is almost at its limit. Thus, a 3.0% increase is a remarkable effect. In addition, when the amount of the additive in the aqueous solution of the additive is large, the temperature of the exhaust gas can be further reduced, which can further save energy.

The concentration of the additive solution, MgO, has been viewed changes used in the range of 0.1% to 20% by weight concentration in terms of CaO no difference in principle, molar ratio S0 ₃ additives solution Was found to have a greater effect. Revised paper (Rule 91) Example 2

 The same procedure as in Example 1 was repeated, except that the addition position of the additive aqueous solution obtained in Example 1 was a flue between the air preheater 4 and the electrostatic precipitator 5, and the flue was added to the flue. A test was conducted to examine the effect of the electric precipitator ash on the pH and acid deposition dust. However, the amount of additive aqueous solution added to the amount of dust is shown in Table 3. The boiler specifications and exhaust gas composition during the test are the same as in Example 1. Table 3 shows the test results. (Table 3)

 PH of acid dust collector ash and acid dust

表 3から、 添加剤水溶液の添加は、 電気集塵器灰の pHと酸性降下煤塵に対し て大きな影響をもち、 十分効果の達成が認められることがわかる。

From Table 3, it can be seen that the addition of the additive aqueous solution has a significant effect on the pH of the precipitator ash and the acid deposition dust, and it is recognized that a sufficient effect is achieved.

In Example 2, it was confirmed that the addition of the additive aqueous solution had a remarkable effect in preventing charging failure of the electrostatic precipitator. The additive solution obtained in Example 1, with the addition amount shown in Table 4 as the conversion amount of MgO in pairs to S0 _3, added to flue between the air preheater 4. The electrostatic precipitator 5 Then, the relationship between the addition of the additive aqueous solution and the driving state of the electrostatic precipitator, the injection amount of ammonia, the pH of the electric precipitator ash, and the charging state of the electric precipitator were investigated. The charging status of the electrostatic precipitator was measured by measuring the current during boiler operation and one month after operation. The results are shown in Table 4. (Table 4)

14 PH and loading status of air dust collector (ash)

本発明にかかる添加剤水溶液はアルカリ性物質であるため、煤塵の電気固有抵 抗値を上昇させ、 同時に電気集塵器灰の pHをも上昇させて酸性硫安を正硫安化 させることができる。 このため、 電気集塵器灰の吸湿性が少なくなり、 流動性が 改善される。 この結果、 表 4からわかるように、 電気集塵器の詰まりが改善され ることになる。 また、 pHが上昇したことから、 アンモニアの注入量の 50%以上 を削減することができる。

Since the additive aqueous solution according to the present invention is an alkaline substance, it is possible to increase the electric resistivity value of the dust and simultaneously increase the pH of the ash of the electrostatic precipitator to convert the acidic ammonium sulfate to normal ammonium sulfate. Therefore, the hygroscopicity of the ash of the electrostatic precipitator is reduced, and the fluidity is improved. As a result, as can be seen from Table 4, clogging of the electrostatic precipitator is improved. In addition, the rise in pH can reduce the amount of injected ammonia by more than 50%.

Further, the concentration of the additive solution, MgO, 0 in terms of the concentration of CaO. 1 is varied in the range of% to 2 0 weight _^0/0, with respect to S0 ₃ 1 mole of the exhaust gas, MgO, of CaO When the aqueous solution of the additive was added to the flue between the air preheater 4 and the electrostatic precipitator 5 in the range of 1 to 20 mol in terms of conversion, the pH became close to 7, and the injection of gamma-moisture was completed. Since the pH remained in the range of 5 to 6 even after stopping, it proved to be a substitute for ammonia. This phenomenon is due to the fact that Mg and Ca salts form sulfate, but acidic sulfate is hardly formed above pH 4.

The additive aqueous solution according to the present invention can be obtained by using a magnesium compound or a calcium compound which is cheaper than an ammonia, and furthermore, there is no restriction on equipment and the safety is high and it is a simple device. It is easier to handle and store than ammonia. Therefore, the economic improvement is of great value. Example 3

 White smoke discharged from wet desulfurization equipment has a phenomenon of long fluttering, which is a kind of polluting situation.

During the tests in Table 4 above, it was observed that white smoke was shortened. The main cause of the white smoke, S0 ₃ is rapidly cooled in the course of contact with the desulfurizing water in the desulfurization apparatus is because it is sulfuric acid mist. Additives aqueous solution according to the present invention, the concentration and condensation absorb S0 ₃ water droplets surface, S0 ₃ and sulfuric acid Maguneshiumu, promotes moisture vaporization of white smoke in the sulfuric acid strength Rushiumu. Therefore, the aqueous solution of the additive was added to the flue in the same procedure as in Example 1 except that the location of addition of the aqueous solution of the additive obtained in Example 1 was in the flue between the electrostatic precipitator 5 and the desulfurizer 6. To investigate the relationship between the addition of the additive aqueous solution and white smoke. Table 5 shows the results. However, the additive solution has had use in amount shown in Table 5 as the conversion amount of MgO with respect to S0 _3.

 (Table 5)

 Relationship between additive aqueous solution addition and white smoke

表 5は、 白煙のたなびきを目視で観察した値である力 僅かに添加剤水溶液が 添加されただけで、 たなびきが明確に短くなっていることが認められる。 実施例 4

Table 5 shows that the fluttering of white smoke is the value observed by visual observation. It can be seen that the fluttering is clearly shortened by the slight addition of the aqueous additive solution. Example 4

The additive solution obtained in Example 1, was injected into the fuel pipe combustion air, it was investigated reduction of dust amount and S0 _3. Table 6 shows the specifications and fuel properties of the boiler used. (Table 6)

 '' Boiler specifications and fuel properties

 Poiler specification

 Model Natural circulation

 250 T / H

 545 ° C

Steam pressure 145 kgf / cm ² Fuel properties Sulfur 5.5%

 twenty one %

 210ppm ~ 330ppm

Na _,; 0 30ppm ~ 60ppm In the actual boiler, the ratio of co-firing of heavy fuel oil C and asphalt varies greatly, and sometimes it is close to that of asphalt firing. Using the boiler shown in Table 6, the weight ratio (Mg ZV) power of the magnesium component in the additive aqueous solution to the vanadium component in the fuel was added so that the weight ratio shown in Table 7 was obtained. The amount of the added aqueous IJ solution was adjusted to the amount shown in Table 7 with respect to the fuel. In order to investigate whether the effect differs depending on the location of addition of the additive aqueous solution, the effect was investigated by adding the additive aqueous solution to the fuel pipe and the combustion air at two locations, respectively. . The fuel was added to the fuel pipe by injecting the additive aqueous solution into the fuel pipe line downstream of the oil heater with a proportional injection pump. The addition to the combustion air was carried out by using a sprayer on the upstream side of the parner. The measurement of the dust amount was measured through silica wool thimble method isokinetic (JIS-Z-8808), S0 3 was measured by the condensation method. Table 7 shows the results. (Table 7) confirmation test of dust and S0 ₃ reduction

From Table 7, the additive solution, it can be seen that there is a significant effect in reducing S0 ₃ content is a major cause of giving a reduction in dust amount, the adverse effect on 'boiler. In particular, M g / V a (weight ratio) of about 3.0, and about lOOOppm der amount of the additive aqueous solution to the fuel Rutoki is dust amount及Pi S0 ₃ weight reducing effect of about 50 %, Indicating that the effect of the aqueous solution of the additive is equal to or better than that of the conventional heavy oil additive. Table 7 shows that the same effect can be obtained regardless of the difference in the addition position, such as in the fuel pipe or in the combustion air. Example 5

Using the additive aqueous solution obtained in Example 1, a high-temperature corrosion test of a heater was performed. Table 8 shows the specifications and fuel properties of the boiler used.

(Table 8) Poiler specifications and fuel properties Poiler specifications

 Model Natural circulation

 115 T / H

 513 ° C

Steam pressure 101 kgf / cm ² Fuel properties

 C heavy oil

 12%

 3% sulfur

 10-30 ppm

Na., 0 10-30 ppm Using the boiler shown in Table 8, the components were added so that the weight ratio (Mg / V) of the magnesium component in the additive aqueous solution to the vanadium component in the fuel was 0.1. In order to improve the dispersibility of the additive in heavy oil, an emulsifier was added to gas oil containing 20% by weight of an additive aqueous solution to form an emulsion. The thus obtained emano-reduction was added to a 100 ppm fuel pipe in terms of MgO with respect to the fuel. Addition to the fuel pipe was performed by injecting the additive emulsion into the fuel pipe line downstream of the oil heater with a proportional injection pump. The high temperature corrosion test of the heater was performed by using the boiler for about one year while adding the additive, and measuring the wall thinning of the water tube of the heater at the time of periodic repair of the boiler about one year later. . Table 9 shows the measurement results. (Table 9)

 Heater tube thinning measurement results

表 9から、 添加剤を添加しない場合、 水管チューブの減肉は、 年間約 0.48mm となるところを、添加剤を添加することにより、減肉分を 75%以上も減少させる ことが確認された。 産業上の利用可能性

From Table 9, it was confirmed that when no additive was added, the wall thickness of the water tube tube was reduced to about 0.48 mm per year. . Industrial applicability

 ADVANTAGE OF THE INVENTION According to the additive concerning this invention, the sulfur oxide in the combustion exhaust gas of a fossil fuel can be efficiently and safely neutralized and removed, and various problems accompanying sulfur oxide generation, for example, environmental degradation Generation of acid dust that causes air pollution, corrosion of air preheaters, electric dust collectors, flue side walls, etc. installed in the flue of fossil fuel combustion exhaust gas, obstruction obstruction, white smoke flow, electric dust collection It is possible to suppress poor charging of the container.

 In addition, high-temperature corrosion due to vanadium and sodium contained in the fuel can be effectively suppressed.

 In addition, the generation of dust can be suppressed.

 According to the power generation method of the present invention, since the additive having the above characteristics is used, in addition to the above-described effects, the temperature of the exhaust gas can be positively reduced, and the efficiency of a combustion device such as a boiler is increased. be able to. In addition, the operating rate and efficiency of combustion equipment such as boilers can be increased, and stable operation can be performed over a long period of time. Further, according to the power generation method of the present invention, while the additive having the above characteristics is manufactured using the exhaust gas, the additive thus obtained is added. A power generation method that is energy saving can be provided.

Claims

The scope of the claims 1. Additive der connexion comprising an aqueous solution of magnesium hydrogen carbonate or bicarbonate of calcium, magnesium concentration component in the additive, in terms of MgO, 0. 1 by weight% to 3 0 wt _^0/0 An additive for a combustion exhaust gas of a combustion device, wherein the additive is 0.1 wt% to 30 wt% in terms of a certain force or a concentration force S, CaO of a calcium component in the additive.  2. At least a part of magnesium hydrogen carbonate or calcium hydrogen carbonate is dissolved in the aqueous solution, and at least a part of magnesium hydroxycarbonate or hydroxycarbonate is suspended in the aqueous solution as fine crystals. Item 1. The additive according to item 1.  3. The additive according to claim 2, wherein 90% by weight or more of the fine crystals have a particle size of 1 μπι or less.  4. introducing fossil fuel exhaust gas into an aqueous liquid containing a magnesium compound or a calcium compound and water;  Pressurizing the aqueous liquid into which the exhaust gas has been introduced, and a step of genorating carbon dioxide in the exhaust gas in the aqueous liquid;  Heating the aqueous liquid to a temperature not lower than the temperature of the gelling step and not higher than the boiling point of the aqueous liquid in order to volatilize and remove the carbon dioxide gel,  A method for producing an additive comprising magnesium hydrogencarbonate or calcium hydrogencarbonate, magnesium hydroxide or calcium hydroxycarbonate, and water.  5. The method for producing an additive according to claim 4, wherein the magnesium compound or the calcium compound is an inorganic substance. 6. The method for producing an additive according to claim 4, wherein a pressure of 9.8 × 10 ⁴ Pa or more is applied when the aqueous liquid is pressurized.  7. Burning fossil fuel with air in a combustion device to obtain steam, and turning a turbine with the steam to generate electric power; The additive according to any one of claims 1 to 3, or the additive obtained by the method according to any one of claims 4 to 6, in the fossil fuel, in the air, inside the combustion device. , Previous corrected paper 0 用紙 .¾] 91) A connection between the combustion device and a flue downstream of the combustion device, or adding to the flue; A power generation method comprising:  8. The power generation method according to claim 7, wherein the additive is added near an outlet of an echo unit in the combustion device or near an outlet of an air preheater in the flue.  9. Combustion of fossil fuel with air in a combustion device to obtain steam and exhaust gas,  Turning a turbine with the steam to generate power;  Introducing at least a part of the exhaust gas into an aqueous liquid containing a magnesium compound or a calcium compound and water;  Pressurizing the aqueous liquid into which the exhaust gas has been introduced, and gelling the carbon dioxide in the exhaust gas in the aqueous liquid;  In order to volatilize and remove the diacid carbon gel, the aqueous liquid is heated to a temperature not lower than the temperature of the gelling step and not higher than the boiling point of the aqueous liquid, and magnesium hydrogen carbonate or calcium hydrogen carbonate is added to the aqueous liquid. Obtaining an additive comprising magnesium oxycarbonate or calcium hydroxycarbonate, and water;  Adding the additive to the fossil fuel, to the air, to the inside of the combustion device, to a connection between the combustion device and a flue downstream of the combustion device, or to the flue. A power generation method, characterized in that: 10. The concentration of the magnesium component in the additive is 0.1% by weight to 30% by weight in terms of MgO, or the concentration of the calcium component in the additive is in terms of CaO. The power generation method according to claim 9, wherein the amount is 0.1% by weight to 30% by weight. 11. At least a part of magnesium hydrogen carbonate or calcium hydrogen carbonate is dissolved in the aqueous liquid, and at least a part of magnesium hydroxycarbonate or hydroxycarbonate floats in the aqueous liquid as fine crystals. The power generation method according to claim 9 or 10, wherein:  12. The power generation method according to any one of claims 9 to 11, wherein 90% by weight or more of the fine crystals have a particle size of 1 µm or less. Corrected paper (rule