JPH09103641A - Flue gas desulfurization facility and boiler equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover the heat energy of flue gas effectively and to reduce the quantity of water used for absorbent slurry by installing a heat recovery means for recovering heat from flue gas before gas-liquid contact which passes through the flue gas introduction part of an absorption column. SOLUTION: Absorbent slurry S1 is supplied from the tank 22 in a bottom part to the header pipe 25 of the flue gas introduction part 21a of an absorption column 21 by a circulating pump 23, sulfur dioxide gas in flue gas is absorbed and removed, and the flue gas is discharged from a flue gas discharge part 21b. A heat exchanger which exchanges heat between a circulating heating medium E and the flue gas of the absorption column 21 of a flue gas desulfurization facility and/or absorbent slurry is used as a heat recovery means. The heat exchanger comprises a heat exchanger tube 31 located upstream from a pipe header 25 in the flue gas introduction part 21a and a heat exchanger tube 32 located downstream from the pipe header 25 (for example, in a filler 26). In this way, the heat energy of flue gas from a boiler is recovered to be used effectively. Besides, the quantity of water used in the desulfurizer can be reduced remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flue gas desulfurization apparatus attached to a boiler facility and the like and a boiler facility for utilizing recovered heat in low heat utilization facilities.

[0002]

2. Description of the Related Art Generally, a flue gas desulfurization device is used to remove sulfur oxides (SO _x ) and the like in flue gas from a boiler facility and release it into the atmosphere as clean gas. FIG.
It is a figure showing the typical composition of the boiler equipment provided with this type of flue gas treatment equipment, and the flue gas temperature and the moisture content in each place.

The smoke emitted from the boiler 1 is the smoke emitted from the boiler 1.
Nitrogen oxides (NO _x ) are removed by the denitration device 2 attached to the air heater 3 (AH) and the gas gas heater (GG).
After passing through the heat recovery section 4 of (H), the electrostatic precipitator 5 (EP)
Introduced into the to remove dust such as fly ash.
Next, the flue gas is guided to the desulfurization device 7 by the upstream fan 6 (IDF) to remove the sulfur oxides (mainly sulfur dioxide gas), and then passes through the reheating section 8 of the gas gas heater (GGH). It is sent to the chimney 10 by the flow fan 9 (BUF) and discharged into the atmosphere. In the flue gas desulfurization apparatus 7 used here, the wet absorption method in which the flue gas is brought into gas-liquid contact with the absorbent slurry to absorb and remove the sulfurous acid gas in the flue gas is excellent in terms of desulfurization rate, etc. Widely used.

The flue gas temperature is usually about 135 ° C. immediately after the air heater 3 (AH), and when the fuel is coal, the moisture content is about 8%. Immediately before the inlet of the flue gas desulfurization apparatus 7, the temperature is lowered to about 90 ° C. by cooling the heat recovery unit 4, etc., and in the flue gas desulfurization apparatus 7, the temperature is further lowered by contact with the absorbent slurry, and the temperature of the coal burning boiler is reduced. Usually 4
It will be about 8 ° C. The flue gas temperature at the outlet of the flue gas desulfurization device 7 is the flow rate and temperature of the flue gas desulfurization introduced, the gas-liquid contact capacity in the flue gas desulfurization device 7, etc., unless heat recovery is performed in the flue gas desulfurization device 7. Since the gas-liquid contact capacity and the like are set according to the nature of the flue gas (sulfurous acid gas concentration, etc.), the flue gas temperature at the outlet of the flue gas desulfurization device 7 depends on the nature of the fuel. Determined almost uniquely. For example,
In the case of coal, it is usually about 48 ° C.

The moisture concentration of the flue gas is saturated at 48 ° C. at the outlet of the flue gas desulfurization device 7 (about 11 because the moisture in the absorbent slurry evaporates until it becomes saturated in the flue gas desulfurization device 7). %). The amount of evaporated water in the absorption tower of the flue gas desulfurization device 7 is about 75 t / h in the case of a 1000 MW class coal-fired boiler. In addition, the flue gas is finally heated by the reheating unit 8 to raise its temperature to about 90 ° C.,
Emitted from the chimney 10.

In the heat recovery section 4, the flue gas temperature is set to 9
Although it is possible to improve the performance of the electrostatic precipitator 5 itself, it is practically impossible to further cool it by cooling it to 0 ° C. or less. That is, when the smoke exhaust temperature is 90 ° C. or lower, the saturated temperature is locally reached and condensed water may be generated. As a result, the ash collected by the electrostatic precipitator 5 becomes moist, making reuse almost difficult. In addition, in order to provide corrosion resistance to condensed water, the heat recovery section 4 is connected to the flue gas desulfurization device 7
It is necessary to use expensive corrosion-resistant materials also for the components such as the duct and the front fan 6 up to.

Further, in the reheating section 8, the flue gas temperature must be raised to about 90.degree. The reason for this is to prevent the corrosion of the downstream equipment, to prevent the smoke emitted from the atmosphere from becoming white smoke, and to ensure the diffusion. That is, unless the temperature is raised to about 90 ° C. or higher, condensed water may be generated, and the chimney 1
It becomes necessary to use an expensive corrosion-resistant material for the components such as the ducts up to 0 and the wake fan 9, and the flue gas emitted to the atmosphere tends to turn into white smoke, and a predetermined diffusivity cannot be obtained. Therefore, when the smoke exhaust temperature is low and sufficient diffusivity cannot be obtained, the smoke does not rise high. Therefore, it is necessary to make the chimney itself high and large so as to satisfy the emission regulation.

[0008]

By the way, in equipment using a boiler such as thermal power generation equipment, in recent years, it has been increasingly demanded to fully utilize the thermal energy generated in the boiler from the viewpoint of effectively utilizing resources. It is desirable to operate heat utilization systems such as greenhouses, hot water pools, and district heating systems with residual heat. However, conventionally, various improvements have been made in order to further improve efficiency, but it has been extremely difficult to recover heat from the boiler equipment.

In the flue gas treatment system, on the other hand, as described above, there is a practical problem in cooling the flue gas at the outlet side of the boiler beyond the current level, and it is considered difficult to recover heat conventionally. It was being done. Also, in the flue gas desulfurization device, it is necessary to replenish the water content of the absorbent slurry as much as it is evaporated and carried away into the flue gas, which causes a problem that the amount of industrial water used is large, and the flue gas is exhausted by this amount of steam. It was necessary to increase the total amount of the fan, increase the power of the wake fan, and enlarge the duct to the chimney.

Therefore, the present invention solves the above drawbacks,
Exhaust gas that can effectively recover the thermal energy of flue gas and enable effective use without changing the main components of flue gas desulfurization equipment and boiler equipment, and reduce the amount of water used for the absorbent slurry. It is intended to provide a smoke desulfurization device and a boiler facility.

[0011]

The present invention is intended to solve the above problems by adopting the following configurations. (1) In a flue gas desulfurization device that brings untreated flue gas and absorbent slurry into gas-liquid contact in the absorption tower, heat that recovers heat from the flue gas that has passed through the flue gas introduction section of the absorption tower before it comes into contact with gas-liquid. A flue gas desulfurization device characterized by having a recovery means.

(2) The flue gas desulfurization apparatus according to (1) above, further comprising heat recovery means for recovering heat from the absorbent slurry circulating in the absorption tower. (3) In the flue gas desulfurization device that brings untreated flue gas and absorbent slurry into gas-liquid contact in the absorption tower, the temperature of the treated flue gas flowing out from the flue gas outlet of the absorption tower is untreated flue gas. The heat recovery amount of the heat recovery means is set so as to be equal to or lower than the saturation temperature for the water concentration in the above (1) or
(2) The flue gas desulfurization equipment described.

(4) In a boiler facility equipped with a flue gas desulfurization device for bringing the smoke emitted from the boiler and the absorbent slurry into gas-liquid contact in the absorption tower, the flue gas passing through the absorption tower and / or the absorption Heat recovery means for recovering heat from the absorbent slurry circulating through the tower, heat recovery means for recovering the heat recovered by the heat recovery means to heat utilization equipment, and heat transferred by the heat transmission means for energy of the heat utilization equipment. A boiler facility characterized by comprising a heat radiation means for radiating heat as a source.

(5) The boiler according to (4) above, characterized in that the heat recovery means recovers heat from at least the exhaust gas passing through the exhaust gas introduction part of the absorption tower before the gas-liquid contact. Facility. (6) The heat recovery amount of the heat recovery means is set so that the temperature of the treated flue gas flowing out from the flue gas outlet of the absorption tower is equal to or lower than the saturation temperature for the moisture concentration in the untreated flue gas. The boiler equipment according to (4) or (5) above, which is characterized in that

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a part of a boiler facility to which the present invention is applied and which supplies heat recovered from a flue gas desulfurization unit to a low heat utilization facility 11, and the flue gas temperature and moisture content at each location are shown together. . In addition, FIG. 2 is a diagram showing an example of a main part configuration of a flue gas desulfurization apparatus to which the present invention is applied, and various heat recovery means are also shown. The same components as those in the conventional example of FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted unless particularly necessary.

In the heat recovery utilization facility of the present invention, as shown in FIG. 1, the low heat utilization facility 11 such as a greenhouse, a hot water pool, and a district heating system is recovered from the flue gas desulfurization device 7 as its energy source. It supplies and uses heat energy. That is, in the flue gas desulfurization device 7, the heat recovery means 12
And a heat transfer means 13 for supplying heat to the low heat utilization facility 11.
And heat radiating means 14 for radiating the transferred heat as an energy source of the low heat utilization equipment 11. It is also possible to use surplus steam from the boiler equipment or steam that has flowed out as the heat energy.

As shown in FIG. 2, the flue gas desulfurization apparatus 7 is of a tank oxidation type, and the absorbent slurry S1 (for example, limestone slurry) is discharged from the tank 22 at the bottom of the absorption tower 21 by the circulation pump 23. Header pipe 25 of smoke introducing section 21a
And is injected into the untreated flue gas A to absorb and remove the sulfurous acid gas in the flue gas. The flue gas is discharged as treated flue gas B from the flue gas outlet 21b. The absorbent slurry injected from the header pipe 25 further flows through the filler 26 of the absorption tower 21 and further absorbs sulfurous acid gas,
It is stored in the tank 22. The tank 22 is provided with an arm rotating air sparger 24, which is rotated horizontally and agitates the slurry, while air C is blown into the tank 22 with fine bubbles to absorb the sulfur dioxide gas and the absorbent slurry. Efficiently contact with air to cause a neutralization reaction, and the entire amount is oxidized to produce gypsum.

The main reactions in the flue gas desulfurization apparatus are as follows. (Absorption _{tower) SO 2 + H 2 O →} H + + HSO 3 - (1) ( ^{_{Tank) H + + HSO 3 - +}} (1/2) O 2 → 2H + + SO 4 2- (2) 2H + + SO 4 2- + CaCO ₃ + H ₂ O → CaSO ₄・ 2H ₂ O + CO ₂ (3)

In this way, the slurry S2 in which the gypsum and a small amount of limestone as the absorbent are suspended is carried out from the tank 22 by a slurry pump (not shown) and supplied to a solid-liquid separator (not shown). Gypsum with low water content after filtering (by-product)
Will be collected as In addition, the flue gas discharge part 21 of the absorption tower 21
A mist eliminator 27 is provided in b for removing mist from the discharged flue gas B after treatment, and the mist is returned to the tank 22 as recovered water D.

The water separated by the solid-liquid separator is
It is sent to a tank (not shown) of the absorbent slurry S1 and is circulated and used as water that constitutes the absorbent slurry. In order to prevent impurities (for example, chlorine) that adversely affect the sulfurous acid gas absorption reaction and the gypsum production reaction from being accumulated in this circulating water, a portion of the circulating water is usually appropriately extracted and discharged.
Further, the circulating water is appropriately supplemented with industrial water as necessary. In the present invention, as will be described later, the amount of water evaporated and carried away in the absorption tower is remarkably smaller than that of the conventional method, so that this make-up water is also greatly reduced.

Next, the heat recovery means 12 of the flue gas desulfurization apparatus 7 will be described in detail with reference to FIG. The heat recovery means 12 can use, for example, a heat exchanger that exchanges heat between the circulating heat medium E and the flue gas of the absorption tower 21 of the flue gas desulfurization device 7 and / or the absorbent slurry. . Here, as the heat medium, for example, the cost can be reduced by using, for example, industrial water to which a chemical agent for preventing corrosion or freezing is added.

As the heat recovery means, for example, as shown in FIG. 2, a heat exchanger composed of a heat transfer pipe 31 is arranged upstream of the header pipe 25 in the smoke introducing portion 21a of the absorption tower 21 to absorb the heat. A heat exchanger consisting of a heat transfer tube 32 is provided downstream of the header pipe 25 of the absorption tower 21 (for example, inside the filler 26) for recovering heat from the high temperature untreated flue gas A before coming into contact with the agent slurry. , That recovers the heat from the smoke and the slurry after the gas-liquid contact, that that disposes the heat from the slurry by disposing the heat exchanger consisting of the heat transfer tube 33 in the slurry in the tank 22 of the absorption tower 21, Circulation pump 23 that sends absorbent slurry from tank 22 to header pipe 25
Of the heat transfer pipe 35 on the way of the discharge pipe and / or the suction pipe of
A heat exchanger 34 including a heat exchanger 34 for recovering heat from the absorbent slurry, and a heat transfer pipe 36 to the smoke exhausting section 21b of the absorption tower 21 (for example, the upstream side of the mist eliminator 27 or the element of the mist eliminator 27). It is possible to use, for example, one that is provided with the heat exchanger 36 and that recovers heat from the flue gas passing through the flue gas outlet 21b.

The heat recovery means 12 may be composed of any one of the above heat exchangers, or a plurality of kinds may be combined in series, for example. However, in order to realize heat recovery at a relatively high temperature, a heat exchanger (heat transfer tube 31) that recovers heat from the untreated flue gas A before contact with the absorbent slurry.
It is preferable to include

The heat recovery amount of the heat recovery means 12 is set so that the temperature of the treated flue gas B finally flowing out from the absorption tower 21 is equal to or lower than the saturation temperature with respect to the water concentration in the untreated flue gas A. It is preferable to set. For example, when the water concentration of the untreated flue gas A is 8%, it is preferable to set the specifications of the heat exchanger and control the circulation amount of the heat medium E so that the temperature is about 40 ° C. or lower.

Further, the heat recovery means 12 may be provided with a control means (not shown) for automatically controlling the heat recovery amount to the target value. For example, this control means includes a concentration sensor for detecting the water concentration of the untreated flue gas A and the absorption tower 2
No. 1 temperature sensor for detecting the gas temperature of the post-treatment flue gas B flowing out from the flue gas discharge section 21a, a flow rate control valve for adjusting the flow rate of the heat medium E, and a target to be adjusted from the detection value of the concentration sensor. The controller may be configured to calculate the temperature and control the opening of the flow rate control valve so that the detected value of the temperature sensor is maintained near the target temperature.

The heat feeding means 13 for feeding the recovered heat to the low heat utilization equipment 11 can be constituted by, for example, a pipe and a feed pump for feeding the heat medium E to the outside in an adiabatic state.
Further, the heat radiating means 14 uses the heat of the heat medium E for low heat utilization equipment 1
1 is a heat exchanger that radiates heat, for example, one that heats the air in the greenhouse, or a heat exchanger that heats the water in the pool.

In the flue gas desulfurization apparatus or the boiler equipment configured as described above, the heat recovery means 12 recovers heat from the flue gas passing through the absorption tower 21 and / or the absorbent slurry circulating through the absorption tower 21. The low heat utilization facility 11 can be effectively operated by heat. In addition, it is also possible to operate the low heat utilization facility 11 by using the excess steam from the boiler facility or the steam that flows out together with the recovered heat of the flue gas desulfurization device.

When a heat exchanger (heat transfer tube 31) for recovering heat from the untreated flue gas A before contact with the absorbent slurry is adopted as the heat recovery means 12, only the amount of flue gas cooled here is used. The amount of evaporation in the gas-liquid contact portion thereafter can be suppressed, and the steady temperature of the slurry in the absorption tower and the temperature of the treated flue gas B can be reduced accordingly.
In particular, the flue gas temperature of the flue gas outlet of the flue gas desulfurization device is equal to or lower than the saturation temperature with respect to the water concentration of the untreated flue gas A (for example, 40 ° C).
(Below), the amount of evaporation at the gas-liquid contact portion of the wake is theoretically zero, and the steady temperature of the slurry in the absorption tower and the temperature of the treated flue gas B are also saturated. Equilibrate below temperature. Actually, there is an influence of heat generated by the reaction in the tank 22, but since this is extremely small, it hardly causes a problem.

As the heat exchanging means 12, a heat exchanger (heat transfer tube 3) for recovering heat from the smoke exhausted on the downstream side of the header pipe 25 (for example, the portion of the filler 26) and the absorbent slurry.
2) is adopted, a heat exchanger (heat transfer tube 33) for recovering heat from the absorbent slurry in the tank 22, or a heat exchanger (heat transfer tube 35 for recovering heat from a slurry on the way of circulating the absorbent slurry). Even when) is adopted, the heat that is about to be added to the slurry side or the heat that is added is continuously collected from the flue gas, so in the steady state, the amount of evaporation at the gas-liquid contact part is only the amount cooled. In addition, the temperature of the slurry in the absorption tower and the temperature of the flue gas B after the treatment can be reduced by that amount. Also in this case, if the temperature of the slurry in the absorption tower and the flue gas is adjusted to the saturation temperature or lower (for example, 40 ° C. or lower) with respect to the water concentration of the untreated flue gas A by setting the heat recovery amount of the heat exchanger, The amount of evaporation at the liquid contact part is theoretically zero.

As the heat exchange means 12, the absorption tower 21 is used.
When adopting a heat exchanger (heat transfer tube 36) for recovering heat from the flue gas passing through the flue gas discharge portion 21b, the untreated flue gas A and the slurry are mixed in the flue gas introduction portion 21a of the absorption tower 21. Steam is once generated by gas-liquid contact, and the temperature of the slurry and smoke in the absorption tower will be the same temperature as before (eg 48 ° C) unless the other heat exchanger is installed, and the water concentration will be the same as before. (For example, 11%). However, in the smoke exhaust lead-out section 21b, the exhaust smoke is cooled, and the water that has once evaporated is condensed in the smoke exhaust lead-out section 21b and is collected by the mist eliminator 27, and eventually, in the absorption tower slurry. The amount of water taken away by evaporation is significantly reduced.
In particular, when the temperature on the outlet side of this heat exchanger (the temperature of the treated flue gas B) is set to be equal to or lower than the saturation temperature (for example, 40 ° C. or less) with respect to the water concentration of the untreated flue gas A (for example, 8%). In theory, all the water that has once evaporated is theoretically recovered as condensed water, and the amount of water carried away from the absorption tower slurry by evaporation becomes zero. Even when the above-mentioned various heat exchangers are combined as the heat exchanging means 12, the evaporation amount (the amount of water evaporated from the slurry and carried away) is reduced as a whole by the amount of cooling by the heat recovery. Can
It can theoretically be set to zero depending on the setting of the heat recovery amount.

[0031]

The present invention has the following various effects by adopting the above-mentioned structure. (1) It is possible to recover the thermal energy of smoke emitted from the boiler and make effective use of it without changing the main configuration of the existing boiler and its associated equipment. In particular, when a heat exchanger that recovers heat from the untreated flue gas A before contact with the absorbent slurry is adopted as the heat recovery means 12, heat exchange with the untreated flue gas A having the highest temperature causes high temperature. Heat recovery is possible.

For example, in a 1000 MW class coal-fired boiler, when the heat recovery means 12 employs a heat exchanger for recovering heat from untreated flue gas A (temperature of about 90 ° C.) before contact with the absorbent slurry, the flow rate is With a configuration in which a heat medium (water) of about 700 t / h is circulated and cooled to a saturation temperature of about 40 ° C., the temperature of the heat medium in the heat radiating means 14 becomes about 70 ° C. in calculation (see FIG. 1), and the It is sufficient as a heat source for hot water pools.

(2) Since the amount of water evaporated from the absorbent slurry in the absorption tower is remarkably reduced, the amount of water supplied, that is, the amount of water used in the desulfurizer can be greatly reduced. In particular, when the heat recovery amount is set so that the temperature of the treated flue gas B is equal to or lower than the saturation temperature with respect to the moisture concentration of the untreated flue gas A, the moisture concentration of the treated flue gas B is untreated. Becomes equal to or less than, and the evaporation amount in the absorption tower (strictly speaking, the amount of water carried away from the slurry in the absorption tower due to evaporation) becomes zero. Therefore, for example, in the case of a 1000 MW class coal-fired boiler, about 75 t / h of water can be saved.

(3) Since the evaporation amount of water in the absorbent slurry in the absorption tower is remarkably reduced, the gas that must be discharged from the absorption tower and released from the chimney to the atmosphere (processed flue gas B)
The total amount of can be significantly reduced. For this reason, if the flow path cross-sectional area of the absorption tower, the mist eliminator 27, and the duct to the reheating unit 8 and the chimney 10 is maintained as it is, the pressure loss is significantly reduced.
The capacity (power consumption) of can be significantly reduced. Further, if the capacity (power consumption) of the downstream fan 9 is maintained as it is, the flow passage cross-sectional area of the absorption tower or the like can be greatly reduced, and the device can be downsized. For example, 100
In the case of a 0 MW class coal-fired boiler, the moisture concentration after treatment is reduced from 11% to 8% or less by reducing the temperature of post-treatment flue gas from 48 ° C to 40 ° C or less, and the total amount of post-treatment flue gas is reduced. It will be reduced by more than 3%.

(4) Absorption tower 21 as heat recovery means 12
When a heat exchanger composed of the heat transfer tubes 32 arranged inside the filling material 26 is used, the temperature of the filling material 26 can be suppressed to be lower than the temperature of the slurry or the flue gas passing therethrough. Almost no water evaporates on the surface of the material 26. For this reason, the soluble component in the slurry does not deposit due to evaporation to generate scale, and it is possible to avoid the problem that the scale adheres to the filler 26.

(5) When the heat recovery means 12 is a heat exchanger provided in the middle of the discharge pipe or the suction pipe of the circulation pump 23, for example, a ready-made heat exchanger is connected in the middle of the pipe. Heat can be recovered from existing desulfurization equipment with a simple modification work.

(6) Absorption tower 21 as heat recovery means 12
When a heat exchanger including a heat transfer tube 36 disposed in the smoke exhaust leading portion 21b (upstream side of the mist eliminator 27 or in the element of the mist eliminator 27) is adopted,
It is possible to further remove the fine dust remaining in the flue gas B after passing through the flue gas discharge portion 21b.

That is, in the flue gas introduction section 21a of the absorption tower 21, steam is once generated due to the gas-liquid contact between the untreated flue gas A and the slurry, and the temperature of the slurry and the flue gas inside the absorption tower is When the exchanger is not provided, the temperature becomes the same as the conventional one (for example, 48 ° C.), and the water concentration becomes the same as the conventional one (for example, 11%). Then, the flue gas is cooled in the flue gas deriving section 21b, and finally brought to a saturation temperature (for example, 40 ° C. or lower) with respect to the moisture concentration (for example, 8%) of the untreated flue gas A. Therefore, the water that has once evaporated is condensed in the smoke exhaust lead-out section 21b, and at that time, the fine dust is captured as the core of the condensed water droplets.

(7) As the heat recovery means 12, the absorption tower 21
When a heat exchanger for recovering heat is disposed in the portion excluding the smoke exhaust lead-out portion 21b, the temperature of the slurry in gas-liquid contact in the absorption tower 21 is constantly lower than in the conventional case, and the absorption reaction of sulfurous acid gas, that is, The reaction of the above reaction formula (1) is promoted,
Desulfurization performance is improved.

(8) Further, the temperature of the treated flue gas B finally derived by adjusting the heat recovery amount is lower than the saturation temperature with respect to the water concentration of the untreated flue gas A (for example, 38).
When the temperature is set to (° C.), not only the water content carried away by evaporation becomes zero, but also the water content in the untreated flue gas A can be conversely taken into the slurry in the absorption tower by condensation. Therefore, it is not necessary to replenish the amount of water discharged for removing the impurities, and the amount of water used can be further reduced.

The present invention is not limited to the above-mentioned embodiment, but may have various modes. For example, the present invention can be applied to any equipment that uses a boiler or equipment that requires a flue gas desulfurization device. For example, the same effect can be obtained even when applied to a waste treatment facility, a steam engine of a ship, and the like. Further, as the heat recovery means, not only the heat exchanger including the heat transfer tube as described above but also a means for passing a heat medium through a jacket provided in the absorption tower may be used. Further, the heat feeding means may be constituted by, for example, a heat pipe.

To summarize the effects of the present invention, when a means for recovering heat from the flue gas that has passed through the flue gas introduction portion of the absorption tower of the flue gas desulfurization apparatus before contact with gas and liquid is provided, high temperature heat recovery is possible. In addition, it is possible to reduce the amount of steam generated in the absorption tower, reduce the amount of water used, reduce the consumption power of the downstream fan of the absorption tower, or downsize the downstream equipment of the absorption tower. You can In addition, since the temperature of the absorbent slurry during absorption and the like constantly decreases, the reactivity of the sulfur oxide absorption reaction increases, and the desulfurization performance improves.

When heat is recovered from the flue gas passing through the absorption tower of the flue gas desulfurization apparatus and / or the slurry of the absorption tower, the temperature of the treated flue gas flowing out from the outlet of the absorption tower is set to the temperature of the untreated flue gas. By setting the heat recovery amount of the heat recovery means so that the temperature becomes equal to or lower than the saturation temperature with respect to the water concentration, almost no water is carried away from the slurry of the absorption tower into the smoke exhaust by evaporation, and the amount of water used is greatly reduced. Made possible

The heat energy of the flue gas recovered by the flue gas desulfurization device can be used as the heat energy source of the low heat utilization facility. For this reason, it is possible to effectively use the thermal energy practically without changing the equipment on the boiler side. For example, when recovering heat from an absorption tower, it is possible to add or install a heat utilization system such as a greenhouse, hot water pool, district heating, etc. without any modification such as increase in boiler capacity. Further, even in a thermal power generation facility or the like, which has conventionally been considered to be practically impossible to recover energy, further residual heat can be recovered. Moreover, such heat recovery not only causes no hindrance to the operation of the boiler equipment and the flue gas treatment device, but is also effective in reducing the amount of water used in the desulfurization device.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a configuration of a main part of a boiler facility to which the present invention is applied, in which a flue gas temperature and a moisture content at each location are shown together on the assumption of an amount of evaporated water of 1000 MW base. .

FIG. 2 is a diagram showing an example of a configuration of a main part of a flue gas desulfurization apparatus to which the present invention is applied, in which various aspects of heat recovery means are also shown.

FIG. 3 is a diagram showing a typical configuration of a conventional boiler equipment provided with a flue gas treatment device, in which flue gas temperature and moisture content at each location are shown together.

Front Page Continuation (72) Inventor Satoshi Yajima 2-5-5 Marunouchi, Chiyoda-ku, Tokyo San Sanbyo Heavy Industries Co., Ltd. Hiroshima Research Institute Co., Ltd. (72) Inventor Susumu Okino 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries Ltd. Hiroshima Research Institute

Claims (6)

[Claims] 1. In a flue gas desulfurization device for bringing untreated flue gas and absorbent slurry into gas-liquid contact in an absorption tower, heat is recovered from the flue gas that has passed through the flue gas introduction section of the absorption tower before the gas-liquid contact. A flue gas desulfurization apparatus, characterized in that it is provided with a heat recovery means. 2. The flue gas desulfurization apparatus according to claim 1, further comprising heat recovery means for recovering heat from the absorbent slurry circulating in the absorption tower. 3. In a flue gas desulfurization device in which untreated flue gas and absorbent slurry are brought into gas-liquid contact in the absorber, the temperature of the treated flue gas flowing out from the flue gas outlet of the absorber is untreated. The flue gas desulfurization apparatus according to claim 1 or 2, wherein the heat recovery amount of the heat recovery means is set so as to be equal to or lower than a saturation temperature with respect to a moisture concentration in the flue gas. 4. A boiler facility provided with a flue gas desulfurization device for bringing the flue gas generated in a boiler and an absorbent slurry into gas-liquid contact in the absorber, the flue gas passing through the absorber and / or the absorber. Heat recovery means for recovering heat from the absorbent slurry that circulates, heat transfer means for transferring the heat recovered by the heat recovery means to heat utilization equipment, and the heat sent by the heat supply means for the energy source of the heat utilization equipment. Boiler equipment characterized in that it is provided with a heat radiating means for radiating heat. 5. The boiler equipment according to claim 4, wherein the heat recovery means recovers heat at least from the flue gas that has passed through the flue gas introduction portion of the absorption tower before being in contact with gas and liquid. 6. The amount of heat recovered by the heat recovery means is adjusted so that the temperature of the treated flue gas flowing out from the flue gas outlet of the absorption tower is equal to or lower than the saturation temperature with respect to the water concentration in the untreated flue gas. The boiler equipment according to claim 4 or 5, wherein the boiler equipment is set.