JP2008275290A - Exhaust heat recovery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a compact exhaust heat recover device capable of performing desulfurization and exhaust heat recovery from exhaust gas at the same time. <P>SOLUTION: Exhaust gas containing SO<SB>X</SB>is introduced from a lower part of a dispersing plate 2 into a device main body 1 of the exhaust heat recovery device. Solid particulates 3 are arranged on the dispersing plate 2. The solid particulates 3 contain particulates that absorb SO<SB>X</SB>. When exhaust gas is introduced into the device main body 1, the solid particulates 3 flow to form a fluidized layer. An internal heat exchanger 4 for recovering heat of exhaust gas is provided inside the fluidized layer. An external heat exchanger 6 for further recovering heat from gas that is desulfurized, heat-recovered, and discharged to the outside is provided at an upper end of the device main body 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an exhaust heat recovery device that recovers heat in exhaust gas exhausted from various heat engines, incinerators, and the like, and particularly includes SO _{X components} such as exhaust gas of marine diesel engines. The present invention relates to an exhaust heat recovery apparatus suitable for recovering heat from exhaust gas.

At the present time, reduction of CO ₂ , which is a greenhouse gas, is strongly demanded, and the price of fossil fuels such as crude oil is expected to rise. Recovery of waste heat is indispensable for using waste heat. Conventionally, heat exchangers have been used to recover waste heat.
By the way, in most of the conventional heat exchangers, it has not been assumed that equipment damage is caused by corrosion. However, when the exhaust gas contains SO _x , such as a marine diesel engine, when exhaust heat is recovered to a low temperature, the SO _{x component} is condensed as sulfuric acid. This will cause damage. As a device that assumes such a case, there is a heat exchanger called "exhaust gas economizer", but in that heat exchanger, in order to prevent sulfuric acid corrosion, exhaust heat recovery to a temperature higher than the temperature at which sulfuric acid is condensed It is only done. Therefore, there is a problem that the efficiency of exhaust heat recovery is poor. In addition, in the heat exchanger, there is a problem that the heat transfer area density cannot be increased from the viewpoint of preventing damage, and an increase in size cannot be avoided.

In order to recover exhaust heat from engines with undesirable exhaust gas properties and to promote further energy savings, exhaust gas purification is performed, and the degree of freedom of installation, etc. is high and the application range is wide and compact. Heat exchange system is necessary.
As a compact heat exchange system, a system using a fluidized bed using a solid-gas mixed phase flow capable of improving the heat transfer coefficient has been put into practical use. For example, what is described in Patent Document 1 is a heat exchanger that recovers thermal energy from the exhaust gas of a combustion furnace containing dust by a fluidized bed. However, such a fluidized bed is used, and there is no conventional example other than a combustor that simultaneously purifies exhaust gas.
As an apparatus for performing desulfurization and heat exchange in a combustor using a fluidized bed, there is an apparatus described in Patent Document 2, which performs desulfurization and heat exchange in a fluidized bed combustor (or boiler), that is, in a high temperature environment. There are no cases where desulfurization and heat recovery are simultaneously performed under low temperature such as exhaust gas conditions.

JP 2004-325065 A JP-A-10-281413

  When exhaust heat is to be recovered from combustion exhaust gas of low-quality fuel that contains a large amount of sulfur, desulfurization is indispensable in order to recover heat up to the sulfuric acid condensation temperature or lower. On the other hand, separately performing desulfurization and heat exchange causes an increase in cost, equipment size, weight, and the like, which is not desirable as a system. If a device that simultaneously performs desulfurization from exhaust gas and exhaust heat recovery can be realized, a system with a large heat recovery amount can be constructed despite its compactness, which contributes to energy saving. it can.

  The present invention has been made in view of such various circumstances, and an object thereof is to obtain a compact exhaust heat recovery apparatus capable of simultaneously performing desulfurization from exhaust gas and exhaust heat recovery. It is to be.

In order to achieve this object, in the present invention, exhaust heat recovery is performed using a fluidized bed, and SO _x is absorbed by solid particles forming the fluidized bed.
That is, the exhaust heat recovery apparatus according to the first aspect of the present invention includes an apparatus main body into which high-temperature exhaust gas is introduced, and the apparatus main body is disposed in the apparatus main body and flows by the introduced exhaust gas to form a fluidized bed. and solid particles, provided in the fluidized bed, and an internal heat exchanger for recovering heat of exhaust gas, consists, in the solid particles forming the fluidized bed, it contains the particles to absorb SO _X It is characterized by.

  According to a second aspect of the present invention, there is provided the exhaust heat recovery apparatus according to the first aspect of the present invention. It is characterized by being.

  According to a third aspect of the present invention, there is provided the exhaust heat recovery apparatus according to the first or second aspect, wherein the solid particles forming the fluidized bed include particles mainly contributing to heat transfer promotion and particles mainly contributing to desulfurization. Is included.

  Furthermore, the exhaust heat recovery apparatus of the present invention according to claim 4 is the invention according to claim 1 or 2, wherein the solid particles forming the fluidized bed include a plurality of types of particles having different desulfurization performances depending on temperature conditions. It is characterized by being included.

  The exhaust heat recovery apparatus of the present invention according to claim 5 is characterized in that, in the invention of claim 1 or 2, the outer wall of the apparatus main body is used as a heat transfer surface.

According to the first aspect of the present invention configured as described above, the solid particles that flow by the exhaust gas and form the fluidized bed include the SO _x absorbing particles, so the SO in the exhaust gas is contained. _X is absorbed by the particles. Therefore, exhaust gas desulfurization is performed. The heat in the exhaust gas is transferred to the flowing solid particles, and is transferred to the heat medium flowing in the internal heat exchanger through the particles. Thus, desulfurization from exhaust gas and exhaust heat recovery are performed simultaneously, and a compact exhaust heat recovery device can be obtained.

  Further, according to the second aspect of the present invention, since the external heat exchanger is provided in addition to the internal heat exchanger, heat is also recovered by the external heat exchanger. In this case, since the exhaust gas discharged to the outside is desulfurized, sulfuric acid does not condense on the external heat exchanger that recovers heat from the exhaust gas. Therefore, it is possible to recover heat up to the sulfuric acid dew condensation temperature or less, and the amount of exhaust heat recovered can be increased.

  According to the third aspect of the present invention, since the fluidized bed is formed by particles mainly contributing to heat transfer promotion and particles mainly contributing to desulfurization, the efficiency of exhaust heat recovery and desulfurization is improved. Can be increased.

  Furthermore, according to the fourth aspect of the present invention, since the solid particles forming the fluidized bed include a plurality of types of particles having different desulfurization performances depending on the temperature conditions, the exhaust gas temperature due to exhaust heat recovery. Regardless of the decrease in desulfurization, desulfurization can be performed over a wide temperature range.

  Further, according to the present invention according to claim 5, since the outer wall of the apparatus main body is used as a heat transfer surface, exhaust heat recovery can be performed more effectively by installing a heat transfer tube or the like on the outer wall. Can do.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram showing a first embodiment of an exhaust heat recovery apparatus according to the present invention.
As is apparent from FIG. 1, high-temperature exhaust gas discharged from various heat engines or incinerators is introduced into the apparatus main body 1 of this exhaust heat recovery apparatus from below, and an upper chimney (not shown) To be discharged. A dispersion plate 2 that allows gas to flow in but prevents solid particles from falling out is provided at the bottom of the apparatus body 1, and the solid particles 3 are disposed on the dispersion plate 2. When exhaust gas is introduced from below the apparatus main body 1, the solid particles 3 flow by the gas to form a fluidized bed. An internal heat exchanger 4 is provided in the apparatus main body 1 at a position surrounded by the fluidized bed. A heat medium is introduced into the internal heat exchanger 4 from an inlet 4a. The heat medium exits from the outlet 4b and is circulated with external equipment such as a steam turbine.

  The outer wall 1a of the apparatus main body 1 is used as a heat transfer surface, and a heat transfer tube 5 is disposed on the outer surface of the outer wall 1a. The heat transfer tube 5 has an upper end as a heat medium inlet 5a and a lower end as a heat medium outlet 5b.

The solid particles 3 are composed of particles that mainly contribute to desulfurization, that is, particles that absorb SO _x , such as particles of activated carbon, iron oxide, quicklime, or a mixture thereof. These particles also contribute to heat transfer promotion. Further, these particles may be mixed with particles mainly contributing to heat transfer promotion, for example, metal particles.

In the exhaust heat recovery apparatus configured as described above, when high-temperature exhaust gas containing SO _x is introduced into the apparatus main body 1 from below, the exhaust gas passes through the dispersion plate 2 and is disposed above the solid particles 3. To touch. As a result, the solid particles 3 flow to form a fluidized bed and absorb the heat of the exhaust gas to a high temperature. The solid particles 3 come into contact with the internal heat exchanger 4 provided inside the fluidized bed, so that the heat of the exhaust gas is transmitted to the heat medium circulating inside the heat exchanger 4 with a high heat transfer rate. It is done. Further, the heat of the exhaust gas is directly transmitted to the heat medium without passing through the solid particles 3. Thus, the heat medium becomes a high temperature. The heat medium is guided to the outside of the apparatus main body 1, and the heat energy is used in an external device such as a steam turbine. Thus, by using the fluidized bed, the heat in the exhaust gas is efficiently recovered.

During this time, the SO _{X component} in the exhaust gas is absorbed by the flowing solid particles 3. That is, exhaust gas desulfurization is performed. Therefore, there is no possibility that sulfuric acid is condensed on the internal heat exchanger 4. As a result, the temperature of the exhaust gas can be lowered to the sulfuric acid condensation temperature or less, and a large amount of heat can be recovered.
In that case, when a plurality of types of particles having different desulfurization performances are mixed with the solid particles 3, desulfurization in a wide temperature range is possible regardless of a decrease in exhaust gas temperature due to exhaust heat recovery. Become.
Moreover, when the solid particles 3 are a mixture of particles mainly contributing to heat transfer promotion and particles mainly contributing to desulfurization, the choice of each particle is widened, and it becomes easy to select an efficient particle.

On the other hand, the outer wall 1a of the apparatus main body 1 also becomes high temperature due to the heat of the exhaust gas. Then, the heat is transferred to the heat medium flowing in the heat transfer tube 5. Thus, heat is also recovered by the heat medium flowing through the heat transfer tube 5. Accordingly, the heat of the exhaust gas is effectively recovered.
This heat medium can be the same as the heat medium circulating in the internal heat exchanger 4, and all exhaust heat recovery can be performed in one exhaust heat recovery system. It is also possible to diversify the field of utilizing exhaust heat by using different heat media (for example, using hot water for a heat source and steam for recovering power).

FIG. 2 is a schematic configuration diagram showing a second embodiment of the exhaust heat recovery apparatus according to the present invention. This second embodiment is a partial improvement of the first embodiment shown in FIG. Therefore, in FIG. 2, parts corresponding to those in FIG.
As is apparent from FIG. 2, in the second embodiment, an external heat exchanger 6 is attached to the upper end of the exhaust heat recovery apparatus of the first embodiment. A heat medium is introduced into the external heat exchanger 6 from an upper inlet 6a. Then, the heat medium is guided to the outside from the outlet 6b at the lower end.

  According to the exhaust heat recovery apparatus of the second embodiment configured as described above, heat is further recovered from the exhaust gas recovered by the fluidized bed and discharged to the outside, so that the heat recovery can be performed more efficiently. Is called. Moreover, since the exhaust gas is desulfurized, sulfuric acid does not condense on the external heat exchanger 6 even if the temperature falls below the sulfuric acid condensation temperature. Therefore, the amount of heat recovery can be increased even if a conventional heat exchanger is used.

  In this embodiment, the heat medium that circulates through the internal heat exchanger 4 and the heat medium that circulates through the external heat exchanger 6 can be the same, and the whole can be configured as one exhaust heat recovery system. In addition, as an internal heat exchanger 4 and an external heat exchanger 6, for example, steam can be obtained from the internal heat exchanger 4 and hot water can be obtained from the external heat exchanger 6.

FIG. 3 is a schematic configuration diagram showing a third embodiment of the exhaust heat recovery apparatus according to the present invention. In the third embodiment, the fluidized bed is a type in which particles are circulated (circulating fluidized bed).
As is apparent from FIG. 3, in the exhaust heat recovery apparatus main body 11, as in the first embodiment, high-temperature exhaust gas discharged from various heat engines or incinerators or the like is below the dispersion plate 12. Has been introduced. The dispersion plate 12 allows gas inflow but prevents solid particles from falling out, and is provided at the bottom of the apparatus main body 11. Solid particles 13 are arranged on the dispersion plate 12, and when exhaust gas is introduced from the lower side of the apparatus main body 11, the solid particles 13 flow by the gas to form a fluidized bed and flow with the flow of the exhaust gas. It spreads out.

The apparatus main body 11 includes a riser part 14 where the particles 13 of the circulating fluidized bed rise, a solid-gas separation part 15 for separating the particles 13 and the gas, and the solid-gas separated particles 13 are guided to the riser part 14. And a valve 17 for adjusting the amount of particles 13 returning to the riser unit 14. The solid particles 13 become a fluidized bed and circulate between them. The gas separated into solid and gas is discharged to the chimney from above the solid and gas separation unit 15.
In order to supplement the solid particles 13 discharged to the outside together with the exhaust gas, a particle supply device 18 is connected to the downstream side of the downcomer unit 16. Further, on the downstream side of the downcomer portion 16, also the particle recovery device 19 for recovering the solid particles 13 that have absorbed the SO _X it is connected.

The downcomer unit 16 is provided with an internal heat exchanger 20 at a position surrounded by the fluidized bed. A heat medium is introduced into the internal heat exchanger 20 from an inlet 20a. And the heat medium comes out from the exit 20b of the internal heat exchanger 20, and is circulated between external apparatuses, such as a steam turbine.
The internal heat exchanger 20 can be arranged in the solid-gas separation unit 15 and the valve 17 in addition to the downcomer unit 16.

An outer wall of the apparatus main body 11, for example, an outer wall 14 a of the riser portion 14 is used as a heat transfer surface, and a heat transfer tube 21 is disposed on the outer surface of the outer wall 14 a. The heat transfer tube 21 has a heat medium inlet 21a at the upper end and a heat medium outlet 21b at the lower end.
In addition to the riser part 14, the outer wall of the solid-gas separation part 15 or the downcomer part 16 can also be used as a heat transfer surface.

The solid particles 13 desulfurize (that is, absorb SO _x ) and contribute to heat transfer promotion, and are made of particles of activated carbon, iron oxide, quicklime, or a mixture thereof.
Further, these particles may be mixed with particles mainly contributing to heat transfer promotion, for example, metal particles.

In the exhaust heat recovery apparatus configured as described above, when high-temperature exhaust gas containing SO _x is introduced into the apparatus body 11 from below the dispersion plate 12, the exhaust gas is disposed above the dispersion plate 12. It contacts the solid particles 13. Thereby, the solid particles 13 flow to form a fluidized bed, and ascend the riser portion 14 with the flow of the exhaust gas. Next, the solid particles 13 descend the downcomer portion 16 through the solid-gas separation portion 15. And it introduce | transduces into the riser part 14 again, controlling the flow volume with the valve | bulb 17. FIG. Thus, the solid particles 13 circulate.

During this circulation, during the period from the riser section 14 to the solid-gas separation section 15, that is, while the exhaust gas and the solid particles 13 are in contact, the solid particles 13 absorb the heat of the exhaust gas and become high temperature. At the same time, it absorbs SO _X in the exhaust gas. That is, heat transfer and desulfurization are performed.
Then, the solid particles 13 that have reached a high temperature come into contact with the internal heat exchanger 20 provided in the downcomer portion 16 inside the fluidized bed, so that the heat of the exhaust gas circulates inside the heat exchanger 20. It is transferred to the medium with a high heat transfer rate. The heat medium is guided to the outside of the apparatus main body 11, and the heat energy is used in an external device such as a steam turbine. Thus, by using the fluidized bed, the heat in the exhaust gas is efficiently recovered.

The exhaust gas thus desulfurized and heat-recovered is discharged from above the solid-gas separator 15 into the chimney. Therefore, the internal heat exchanger 20 provided in the downcomer portion 16, exhaust gas containing SO _X is hardly contacted. As a result, there is no possibility that the sulfuric acid is condensed on the internal heat exchanger 20, so that it is possible to recover the exhaust heat up to the sulfuric acid condensation temperature or lower.

  The operation effect by the kind of solid particle 13 and the operation effect by having provided the heat exchanger tube 21 are the same as that of Example 1. FIG.

FIG. 4 is a schematic configuration diagram showing a fourth embodiment of the exhaust heat recovery apparatus according to the present invention. The fourth embodiment is an improvement of the third embodiment. Therefore, in FIG. 4 showing the fourth embodiment, parts corresponding to those of the third embodiment of FIG.
As is apparent from FIG. 4, the fourth embodiment is obtained by attaching an external heat exchanger 22 to the upper end of the solid-gas separation unit 15 in the exhaust heat recovery apparatus of the third embodiment. A heat medium is introduced into the external heat exchanger 22 from an upper inlet 22a. Then, the heat medium is guided to the outside from the outlet 22b at the lower end.

  According to the exhaust heat recovery apparatus of the fourth embodiment configured as described above, heat is further recovered from the exhaust gas recovered by the fluidized bed and discharged to the outside, so that the heat recovery is performed more efficiently. Is called. Moreover, since the exhaust gas is desulfurized, sulfuric acid does not condense on the external heat exchanger 22 even if the temperature falls below the sulfuric acid condensation temperature. Therefore, the amount of heat recovery can be increased even if a conventional heat exchanger is used.

  Also in this embodiment, the heat medium that circulates through the internal heat exchanger 20 and the heat medium that circulates through the external heat exchanger 22 are the same, and the whole can be configured as one exhaust heat recovery system. Further, as an internal system different from the internal heat exchanger 20 and the external heat exchanger 22, for example, steam is generated from the internal heat exchanger 20, and hot water can be obtained from the external heat exchanger 22.

FIG. 5 is a schematic configuration diagram showing a fifth embodiment of the exhaust heat recovery apparatus according to the present invention. The fifth embodiment is an embodiment in which the present invention is applied to recover exhaust heat from the exhaust gas of a marine diesel engine. When the present invention is applied to a ship, it is necessary to select one that is not easily affected by hull shaking. Therefore, the above-described fourth embodiment using a circulating fluidized bed was adopted.
In FIG. 5, the same reference numerals are given to the portions corresponding to the fourth embodiment of FIG. 4.
As is clear from FIG. 5, the exhaust gas discharged from the marine diesel engine 30 is introduced into the apparatus main body 11 of the exhaust heat recovery apparatus mounted on the ship from below the dispersion plate 12. ing. The exhaust heat recovery apparatus uses a circulating fluidized bed. When exhaust gas is introduced from below the apparatus main body 11, the solid particles 13 on the dispersion plate 12 flow by the gas to form a fluidized bed. It spreads and circulates along with the flow of gas.

That is, when exhaust gas is introduced from below the dispersion plate 12, the exhaust gas contacts the solid particles 13 disposed above the dispersion plate 12. Thereby, the solid particles 13 flow to form a fluidized bed, and ascend the riser portion 14 with the flow of the exhaust gas. Next, the solid particles 13 reach the solid-gas separation unit 15 made of a cyclone, and are separated from the gas in the solid-gas separation unit 15, and descend the downcomer unit 16. And it introduce | transduces into the riser part 14 again, controlling the flow volume with the valve | bulb 17. FIG. Thus, the solid particles 13 circulate in the apparatus main body 11.
The solid-gas separated gas is discharged from above the solid-gas separation unit 15 to the chimney.

The downcomer unit 16 is connected to a particle supply device 18 for supplementing the solid particles 13 discharged to the outside together with the gas. A particle recovery device 19 that recovers the solid particles 13 that have adsorbed SO _X is connected to the downstream side of the downcomer section 16.

Further, the downcomer section 16 is provided with an internal heat exchanger 20 at a position surrounded by the fluidized bed. On the other hand, the outer wall 14a of the riser portion 14 is used as a heat transfer surface, and the heat transfer tube 21 is disposed on the outer surface of the outer wall 14a. Further, an external heat exchanger 22 is attached to the upper end of the solid-gas separation unit 15 so that heat is recovered from the gas discharged to the outside.
And the water which is a heat medium circulates among these.
That is, the water supplied by the feed water pump 31 enters the internal heat exchanger 20 from the lower end inlet 20a, is heated to become steam, and exits from the upper end outlet 20b. The steam is further heated while passing from the upper end inlet 21 a to the lower end outlet 21 b through the heat transfer pipe 21 arranged on the outer surface 14 a of the riser portion 14, and is guided to the steam turbine 32 a of the turbine generator 32. The steam whose temperature has been lowered by driving the turbine generator 32 is returned from the turbine generator 32 to water in the condenser 33. The water is sent into the external heat exchanger 22 from the upper end inlet 22a of the external heat exchanger 22 by the condensate pump 34, and is heated while passing through the external heat exchanger 22 to become hot water. Then, the hot water is sent from the lower end outlet 22 b of the external heat exchanger 22 to the feed water pump 31 and is supplied to the internal heat exchanger 20 again.

On the other hand, the solid particles 13 circulating in the apparatus main body 11 absorb and desulfurize SO _X in the exhaust gas while in contact with the exhaust gas, that is, from the riser unit 14 to the solid gas separation unit 15. At the same time, the heat of the exhaust gas is absorbed and the temperature becomes high. Then, the solid particles 13 that have reached a high temperature come into contact with the internal heat exchanger 20 provided in the downcomer portion 16 inside the fluidized bed, so that the heat of the exhaust gas circulates inside the heat exchanger 20. It is transferred to the medium with a high heat transfer rate. In this way, exhaust gas desulfurization and heat transfer are performed simultaneously.
In that case, since the heat transfer coefficient in the fluidized bed is larger than the simple heat transfer coefficient in the gas phase, the equipment can be made compact, and it can contribute to the effective utilization of the limited ship space. Moreover, by performing desulfurization, heat recovery to a low temperature is possible.

Further, since the heat is further recovered by the external heat exchanger 22 from the exhaust gas recovered by the fluidized bed and discharged to the outside, the overall heat recovery efficiency becomes extremely high. Moreover, since the exhaust gas is desulfurized, sulfuric acid does not condense on the external heat exchanger 22 even if the temperature falls below the sulfuric acid condensation temperature. Therefore, the heat recovery amount can be increased.
In this way, an exhaust heat recovery system having a large heat recovery amount despite being compact can be obtained. And since the turbine generator 32 is driven by the recovered heat to generate power, it can contribute to energy saving.

A performance test was performed on the desulfurization agent used in such an exhaust heat recovery apparatus. FIG. 6 shows the test results. As the gas to be desulfurized, a component-controlled simulated exhaust gas was used. In FIG. 6, the horizontal axis represents the temperature of the simulated exhaust gas, and the vertical axis represents the desulfurization performance.
As is apparent from FIG. 6, the iron oxide-based desulfurization agent exhibits high performance at a low temperature of 400 ° C. or lower. On the other hand, in an experiment in which water vapor generated when a hydrocarbon fuel is burned is added to the simulated exhaust gas, the performance of quicklime has increased.
From this test result, it can be seen that satisfactory desulfurization is performed by selecting appropriate particles according to the properties of exhaust gas and temperature conditions.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the embodiment, and various design changes can be made within the scope of the present invention.

It is a schematic block diagram which shows 1st Example of the waste heat recovery apparatus by this invention. It is a schematic block diagram which shows 2nd Example of the waste heat recovery apparatus by this invention. It is a schematic block diagram which shows 3rd Example of the waste heat recovery apparatus by this invention. It is a schematic block diagram which shows 4th Example of the waste heat recovery apparatus by this invention. It is a schematic block diagram which shows 5th Example of the waste heat recovery apparatus by this invention. It is a graph which shows the performance test result of the particle | grains used as a desulfurization agent.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 1a Outer wall 2 Dispersion plate 3 Solid particle 4 Internal heat exchanger 4a Inlet 4b Outlet 5 Heat transfer tube 5a Inlet 5b Outlet 6 External heat exchanger 6a Inlet 6b Outlet 11 Apparatus main body 12 Dispersion plate 13 Solid particle 14 Riser part 14a Outer wall 15 Solid-gas separation unit 16 Downcomer unit 17 Valve 18 Particle supply device 19 Particle recovery device 20 Internal heat exchanger 20a Inlet 20b Outlet 21 Heat transfer tube 21a Inlet 21b Outlet 22 External heat exchanger 22a Inlet 22b Outlet 30 Marine diesel engine 31 Water supply pump 32 Turbine generator 32a Steam turbine 33 Condenser 34 Condensate pump

Claims (5)

A device body into which high-temperature exhaust gas is introduced;
Solid particles arranged in the apparatus body and flowing by the introduced exhaust gas to form a fluidized bed,
An internal heat exchanger provided in the fluidized bed and recovering the heat of the exhaust gas,
An exhaust heat recovery apparatus, wherein solid particles that form the fluidized bed contain particles that absorb SO _x .   The exhaust heat recovery apparatus according to claim 1, further comprising an external heat exchanger for recovering heat from a gas that is desulfurized and heat recovered and discharged to the outside of the apparatus main body.   The exhaust heat recovery apparatus according to claim 1 or 2, wherein the solid particles forming the fluidized bed include particles mainly contributing to heat transfer promotion and particles mainly contributing to desulfurization.   3. The exhaust heat recovery apparatus according to claim 1, wherein the solid particles forming the fluidized bed include a plurality of types of particles having different desulfurization performances depending on temperature conditions.   The exhaust heat recovery apparatus according to claim 1, wherein an outer wall of the apparatus main body is configured to be used as a heat transfer surface.

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