JPH06254342A - Dry type waste gas desulfurizer - Google Patents

Abstract

PURPOSE:To provide the dry type waste gas desulfurizer having a waste gas introducing mechanism which can stably maintain high desulfurization performance by applying adequate swirling and rising flow to the waste gases to be introduced into a dry type waste gas desulfurization column for removing the SOx in the waste gases and spraying humidifying water in the state of uniformly dispersing desulfurizing absorbents. CONSTITUTION:The waste combustion gases contg. the SOx are introduced in the state of suspending the powdery desulfurizing agents therein into the desulfurization column 16 and the water is sprayed via a nozzle 15 in the inlet section of the desulfurization column to absorb away the SOx in the waste gases before the fine liquid drops complete the evaporation in the desulfurization column. The lower part of the cylindrical barrel of the desulfurization column 16 is successively provided with a conical barrel 14 having an aperture of a prescribed size in the bottom. A waste gas introducing duct 12 contg. a swirling vane chamber 18 for swirling and raising the waste gases 1 in the desulfurization column along the inside surface of the conical barrel 14 from the aperture in the bottom of the conical barrel 14 is connected to the bottom of the conical barrel 14. Consequently, the high desulfurization performance is stably maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry type exhaust gas desulfurization device for removing sulfur oxides in combustion exhaust gas, and in particular, a swirl upward flow is applied to exhaust gas introduced into a desulfurization tower to uniformly disperse a desulfurization absorbent. The present invention relates to a dry exhaust gas desulfurization device equipped with an exhaust gas introduction mechanism suitable for maintaining stable desulfurization performance.

[0002]

2. Description of the Related Art As one of the conventional methods for removing sulfur oxides in combustion exhaust gas, after spraying or atomizing an absorbent such as slaked lime in an exhaust gas duct, a desulfurization tower provided downstream of the absorbent is used for humidification. FIG. 5 and FIG. 6 show an example of the configuration of a dry flue gas desulfurization apparatus that performs water spraying to absorb and remove sulfur oxides in exhaust gas. Note that FIG. 6 shows the structure of the desulfurization tower inlet for introducing the exhaust gas. Exhaust gas 1 generated by combustion in a furnace such as a boiler is guided to a desulfurization tower 5 from an exhaust gas inlet duct 4. On the other hand, in the exhaust gas inlet duct 4, the absorbent 2
Is sprayed, and the absorbent 2 is introduced into the desulfurization tower 5 in a state of being suspended in the exhaust gas 1. A spray nozzle 7 for the humidifying water 3 is provided in the desulfurization tower 5, and the evaporation is completed before the sprayed fine droplets reach the desulfurization tower 5 outlet. The substance is absorbed by the absorbent 2 through the fine droplets of the humidifying water 3. The structure of the exhaust gas introduction part of the conventional dry exhaust gas desulfurization tower is, for example, as shown in FIG. 6, the rectification part 10 and the rectification cone part 1 for introducing the exhaust gas 1 from the inlet duct 9 and dispersing the absorbent 2 in the desulfurization tower 5.
1 was provided. As a conventional technique, for example, Japanese Utility Model Laid-Open No. 2-133414 can be cited.

[0003]

The above conventional technique is shown in FIG.
Further, as shown in FIG. 6, since the rectifying section 10 and the rectifying cone section 11 for rectifying the exhaust gas are included, the tower height of the desulfurization tower 5 is inevitably high. Further, since the rectifying effect in the rectifying cone portion 11 is small, the gas flow velocity in the desulfurization tower 5 becomes non-uniform, and the distribution of the absorbent 2 is unevenly distributed, the absorbent 2 and the humidifying water 3 are evenly contacted with each other. However, in order to maintain the desulfurization performance at a high level, a larger amount of the absorbent 2 is required and the economy is reduced. In addition to this, the absorbent 2 adheres to a part of the wall of the desulfurization tower 5 (hereinafter referred to as scaling), grows and peels, and falls as a solid matter, and this solid matter falls, for example, on the rectifying cone portion 11 There was a problem such as accumulation on the sloping surface of No. 1 and the continuation of desulfurization operation became impossible.

The object of the present invention is to solve the above-mentioned problems in the prior art and to give an appropriate swirl upward flow to the exhaust gas to be introduced into the dry exhaust gas desulfurization tower for removing the sulfur oxides in the combustion exhaust gas to provide a desulfurization absorbent. It is an object of the present invention to provide a dry type exhaust gas desulfurization apparatus equipped with an exhaust gas introduction mechanism capable of spraying humidifying water in a uniformly dispersed state and stably maintaining high desulfurization performance.

[0005]

In order to achieve the above-mentioned object of the present invention, the present inventors have found that it is effective to give an appropriate swirl upward flow to exhaust gas as a result of a flow analysis simulation. It was As a concrete means of this,
For example, a method of connecting the exhaust gas duct with eccentricity to the center of the desulfurization tower like a dust collection cyclone is conceivable.
When a desulfurization tower with a tower height of 30 m or more, which is generally adopted, is configured as a cylindrical self-supporting type, structurally unreasonable problems occur, and the exhaust gas introduction part buckles and is apt to be damaged unless it is reinforced in phase. Is inevitable. Therefore, compared with the method of introducing the exhaust gas by aligning the center axis of the desulfurization tower with the center line of the duct for introducing the exhaust gas, a large amount of components and processing man-hours are required, which is not economical. Therefore, in order to match the center line of the desulfurization tower and the center line of the duct and to introduce an exhaust gas from the bottom of the desulfurization tower by a wide duct to give an appropriate swirling force, a swirl vane chamber having a plurality of exhaust gas swirl vanes is provided, And, in each of the swirl vanes, an inclined roof plate adjusted so that the introduction cross-sectional area of the exhaust gas becomes narrower from the exhaust gas inlet portion of the chamber in which the swirl vanes are arranged so that an equal amount of exhaust gas is introduced to the wake. It is configured to be provided. Further, in order not to prevent the fall of the solid matter adhered and accumulated in the desulfurization tower, the drop passage has a smooth internal shape without protrusions such as obstacles. The present invention introduces a powdered desulfurizing agent suspended in a combustion exhaust gas containing sulfur oxides into a desulfurization tower, and sprays water through a nozzle at a desulfurization tower inlet to form fine droplets of the desulfurization tower. In a dry exhaust gas desulfurization apparatus that absorbs and removes sulfur oxides in exhaust gas until the completion of evaporation in a conical cylinder having an opening of a predetermined size at the bottom of the cylindrical cylinder of the desulfurization tower. And a wide exhaust gas introduction duct containing a swirl vane chamber for swirling and raising exhaust gas into the desulfurization tower along the inner surface of the conical cylinder from the bottom opening of the conical cylinder is connected to the lower part of the conical cylinder. It is a dry exhaust gas desulfurization device. And, in the dry exhaust gas desulfurization apparatus of the present invention, it is structurally desirable to arrange the center line of the exhaust gas introduction duct and the central axis of the cylindrical portion of the desulfurization tower so as to be aligned, and to appropriately swirl the exhaust gas. Of the swirl vane of the exhaust gas, the swirl number (S _B ) defined by the following (Equation 1) is 0.35 to 0.35 in order to uniformly disperse the desulfurization agent and maintain high desulfurization efficiency.
It is a dry exhaust gas desulfurization apparatus having a swirl control means for giving a swirl strength in the range of 0.65. (Wherein, Jifai = torque, G _Z = upward direction momentum, R = a representative _{dimension.) S B = Gφ / G} Z / R ......... ( number 1) Further, the present invention is of the swirl vane chamber It is preferable to provide a conical portion in the lower part in contact with the inner casing of the swirl vane chamber, and to provide a means for facilitating the discharge of the solid matter that adheres to and grows in the desulfurization tower and peels off to the outside of the tower.

[0006]

In order not to hinder the fall of the solid matter adhered and grown in the desulfurization tower, the tip of the inner side of the swirl vane is prevented from protruding from the inner side of the inner casing of the swirl vane chamber, and the swirl vane is The absorbent can be uniformly dispersed in the desulfurization tower by using a variable vane configured to always provide an optimum swirling force according to the change in the exhaust gas amount.

[0007]

Embodiments of the present invention will be described below in more detail with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a desulfurization tower of the dry exhaust gas desulfurization apparatus of the present invention. In the figure, an exhaust gas 1 generated from a boiler furnace or the like is a desulfurization tower 16
From the exhaust gas introduction wide duct 12 provided with the central axis of the exhaust gas and the center line of the exhaust gas introduction duct aligned,
Is introduced into the swirl vane chamber portion 18 having the inclined roof plate 24 in which is installed, an equal amount of exhaust gas is supplied between the swirl vanes 13, and the swirl upward flow is given to the exhaust gas. On the other hand, since the amount of exhaust gas changes depending on the load of the gas generation source, the inlet exhaust gas flow rate detector (exhaust gas flow meter) 19 is used to apply an appropriate turning force to the exhaust gas according to the load, as shown in FIG. The amount of exhaust gas is detected, and the computing unit 20 calculates the swirl number, which is a turning parameter of the exhaust gas. Here, the swirl number (S _B) is defined by equation (1) below. S _B = Gφ / G _Z / R (Equation 1) G φ = rotational moment G _Z = upward axial momentum R = representative dimension The angle of the swirl vane 13 is adjusted by this swirl number (S _B ) to generate exhaust gas. An optimum turning force can be given depending on the load of the source.

<Experimental example> In order to understand the optimum condition of the swirl vane 13, an experiment was conducted using a small model device shown in FIG. The relationship between the small model and the actual machine was correlated by matching the Froude number and the inertial parameters shown in the following (Equation 2) and (Equation 3). Froude number (Fr) = U ² / (g · De) (Equation 2) Inertia parameter (Φ) = (8 · ρ _P · D _P ) / (6 · C _D · ρ ·
De) (Equation 3) where: U: Gas flow velocity (m / s) g: Gravitational acceleration (m ² / s) De: Tower diameter (m) ρ _P : Apparent density of absorbent D _P : Absorbent particles diameter C _D: absorber resistance coefficient [rho: the absorbent concentration in the column in each position of the gas density miniature model was measured and the respective swirling force, i.e. the coefficient of variation absorber concentration distribution in the swirl number (S _B) using Fig. 4 shows the result of the arrangement. However, the coefficient of variation was calculated by the following equation (4). Coefficient of variation (%) = (standard deviation) / (average value) × 100
...... As shown in equation (4) FIG. 4, in the swirl S _B number 0.5, absorbent concentration variation coefficient is about 15%. Also, 0.35
<Between S _B <0.65, so was not observed most variation in absorption concentration, 0.35 <S _B <0.65 is appropriate region. Therefore, the angle of the swirl vane may be adjusted according to the load, and the swirl vane angle may be controlled so that the swirl number S _B can be maintained within the above range. When introducing the exhaust gas into the desulfurization tower, the gas flow velocity is usually about 15 m / s, but the height of the exhaust gas introduction duct can be reduced by adopting the wide duct 12 which is almost equal to the diameter of the desulfurization tower. . As a result, the height of the desulfurization tower can be suppressed by minimizing the required height of the exhaust gas introduction section.
In addition, by providing the ceiling of the swirl vane chamber portion 18 in which the swirl vanes 13 are installed with an inclination (sloping roof plate 24), the amount of exhaust gas introduced to each swirl vane 13 is made uniform and the exhaust gas flow is stabilized. It is configured to give a turning force. In addition, the exhaust gas flow meter 19 even when the load changes
The gas flow rate detected by
Dispersing the absorbent evenly in the desulfurization tower by calculating the optimum swirl vane angle based on the _B number and adjusting and controlling the variable vane angle so that an appropriate swirling force can be given. It is possible to promote good contact with water droplets in the water spraying area, so that the absorbent can be effectively used and the desulfurization performance can be stably maintained.

[0009]

According to the present invention, the tower height is reduced by adopting a wide duct in which the center of the desulfurization tower and the center of the exhaust gas introduction duct are matched (for example, in a desulfurization tower having a diameter of 10 m, the height is reduced by about 4 m). It is possible to uniformly disperse the absorbent by giving an optimum swirling force to the exhaust gas, and the utilization rate of the desulfurized absorbent can be improved. Further, even when the load of the exhaust gas generation source changes, by adjusting and controlling the variable vanes, it is possible to disperse the absorbent in the desulfurization tower almost uniformly, and to stably maintain high desulfurization performance.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a structure of an exhaust gas introducing part of a desulfurization tower exemplified in an example of the present invention.

FIG. 2 is a schematic diagram showing a control system of a variable vane that gives a swirl flow to the exhaust gas as exemplified in the embodiment of the present invention.

FIG. 3 is a schematic diagram showing the configuration of a small model device that determines the optimum conditions of the swirl vanes illustrated in the embodiment of the present invention.

FIG. 4 is a graph showing the relationship between the swirl number and the absorbent concentration variation coefficient of the swirl vane illustrated in the example of the present invention.

FIG. 5 is a schematic diagram showing the structure of a conventional desulfurization tower.

FIG. 6 is a schematic diagram showing the structure of an exhaust gas introduction section of a conventional desulfurization tower.

[Explanation of symbols]

 1 ... Exhaust gas 2 ... Absorbent 3 ... Humidifying water 4 ... Exhaust gas inlet duct 5 ... Desulfurization tower 6 ... Outlet duct 7 ... Spray nozzle 8 ... Dust discharge pipe 9 ... Inlet duct 10 ... Rectifying part 11 ... Rectifying cone part 12 ... Exhaust gas introduction Wide duct 13 ... Swirl vane 14 ... Cone part 15 ... Humidification water spray nozzle 16 ... Desulfurization tower 17 ... Dust discharge cone 18 ... Swirl vane chamber part 19 ... Exhaust gas flow meter (inlet exhaust gas flow rate detector) 20 ... Calculator 21 ... Link mechanism 22 ... Wide duct for introducing exhaust gas 23 ... Swivel vane 24 ... Sloping roof plate 25 ... Straight body part 26 ... Inner casing 27 ... Outer casing

Claims (4)

[Claims] 1. A desulfurizing agent in the form of powder suspended in a combustion exhaust gas containing sulfur oxides is introduced into a desulfurizing tower, and water is sprayed through a nozzle at the desulfurizing tower inlet to desulfurize fine droplets. In a dry exhaust gas desulfurization apparatus that absorbs and removes sulfur oxides in exhaust gas until the evaporation is completed in the tower, a conical cylinder having a bottom with an opening of a predetermined size in the lower part of the cylindrical body of the desulfurization tower. An exhaust gas introduction duct containing a swirl vane chamber for swirling and raising exhaust gas into the desulfurization tower along the inner surface of the conical cylinder from the bottom opening of the conical cylinder is connected to the lower part of the conical cylinder. A dry type exhaust gas desulfurization device characterized in that 2. A dry type exhaust gas desulfurization apparatus according to claim 1, wherein the center line of the exhaust gas introduction duct and the center axis of the cylindrical portion of the desulfurization tower are aligned with each other. 3. An apparatus according to claim 1 or claim 2, with respect to the pivot vanes, pivoting strong range of swirl number defined by (Equation 1) below (S _B) is 0.35-0.65 A dry-type exhaust gas desulfurization apparatus, which is provided with a control means for imparting strength. _{S B = Gφ / G Z /} R ......... ( number 1) (wherein, Jifai = torque, G _Z = upward axial movement amount, indicating a R = typical dimension.) 4. A cone portion is provided below the swirl vane chamber in contact with an inner casing of the swirl vane chamber according to any one of claims 1 to 3, and grows and separates and falls in a desulfurization tower. A dry-type exhaust gas desulfurization apparatus, characterized in that means for facilitating the discharge of the solid matter to the outside of the tower is provided.