JP2005308382A - Circulating fluidized bed boiler device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circulating fluidized bed boiler capable of solving a problem on high-temperature corrosion of an external heat exchanger, and realizing high efficiency in power generation. <P>SOLUTION: In this circulating fluidized bed boiler device comprising a furnace 1 having a fluidized bed, a first cyclone 2 introducing combustion gas of high temperature from the furnace and collecting particles discharged following the combustion gas, a convection heat transfer part 8 generating steam by heat exchanging, by supplying the combustion gas with particles separated in the first cyclone 2, and a circulating line for introducing the particles separated in the first cyclone 2, recovering the heat therefrom and returning the particles to the furnace 1, four fluidized bed sections composed of spaces sectioned by common partitioning walls 300, 400, 500 are defined on the circulating line, air inlet ports 302, 401, 501, 602 are formed on the respective sections, and the efficiency in collecting chlorine-containing dust by the cyclones 2, 7 is increased by properly setting a flow rate of the introduced air, thus high-temperature corrosion of boiler tubes connected with power generating equipment is prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a circulating fluidized bed boiler apparatus having a wide range of fuel compatibility from gas to liquid and solid, and can solve the problem of high temperature corrosion in an external heat exchanger and realize high efficiency of power generation. About.

  Waste power generation makes a significant contribution as a stable source of renewable energy to replace conventional fossil fuels, as a measure to prevent global warming, and as a measure to reduce landfill amounts that will prolong the life of final disposal sites. It is expected to contribute to the improvement of global energy problems, global environmental problems, and community problems.

  As a target for introducing waste power generation in FY2010 submitted in June 2001, a target of 4.17 million KW, which is 30% of all new energy, has been set. Since the actual result in 1999 is about 900,000 KW, it is said that it is necessary to increase the installed capacity five times.

  In addition, the legal system for building a recycling-oriented society has been steadily developed and reviewed, and since April 2003, the Special Measures Law (RPS system) concerning the use of new energy has been fully implemented. It is expected that new energy power generation will be promoted for waste such as garbage, sewage sludge, food waste, agriculture / forestry / fishery waste, papermaking black liquor, and building waste.

In the promotion of new energy power generation, in recent years, circulating fluidized bed boilers that enable ultra-high efficiency power generation from waste combustion, which is the core of the waste power generation field, have attracted attention.
JP 2001-248804 A

  As shown in FIG. 6, a conventional circulating fluidized bed boiler apparatus includes a furnace 50 having a fluidized bed, a cyclone 51, circulation lines 52A and 52B, a convection heat transfer section 53, an external heat exchanger 54, and a bag filter 55. It has.

  When combustion starts in a state where fuel such as waste, auxiliary fuel, dense bed materials such as gravel and sand, and circulating solids supplied to the bottom of the furnace 50 are fluidized by combustion air, high-temperature combustion gas is generated. The generated combustion gas is accompanied by some particles of the dense bed material and sent to the cyclone 51 to collect the particles.

  The particles collected by the cyclone 51 are discharged downward and returned to the furnace 50 via the circulation lines 52A and 52B. An external heat exchanger 54 is disposed in the middle of the circulation lines 52A and 52B.

  The particles collected by the cyclone 51 are supplied to the external heat exchanger 54 via the circulation line 52A, and after being recovered, they are returned as a circulation solid to the dense bed portion at the bottom of the furnace 50 via the circulation line 52B. The particles passing through the external heat exchanger 54 are deprived of heat and become a cold solid.

  The hot gas and ash separated from the cyclone 51 are sent to the convection heat transfer section 53. Heat is recovered from the hot gas at the convection heat transfer section 53.

  Thereafter, the heat-recovered gas is sent to the bag filter 55 together with the ash and separated into exhaust gas and ash, and the exhaust gas is treated with an exhaust gas if necessary and discharged outside the system.

  In such an apparatus, high-temperature and high-pressure steam is generated using heat recovered by the external heat exchanger 54 and the convection heat transfer unit 53.

  However, the waste that is the fuel source contains corrosive components such as chlorine and alkali metals. When these concentrations increase, the corrosive components flow into the external heat exchanger, There is a problem that the high temperature corrosion of the steel also increases to a level that cannot be ignored.

  Then, this invention makes it a subject to provide the circulating fluidized bed boiler apparatus which can eliminate the problem of the high temperature corrosion in an external heat exchanger, and can implement | achieve efficiency improvement of electric power generation.

  As a result of intensive studies to solve the above problems, the present inventor has reached the present invention. That is, the said subject is solved by each following invention.

(Claim 1)
A furnace having a fluidized bed, a first cyclone that introduces high-temperature combustion gas from the furnace and collects particles discharged accompanying the combustion gas, and a combustion gas from which particles are separated by the first cyclone In a circulating fluidized bed boiler apparatus comprising: a convection heat transfer section that supplies and generates steam by heat exchange; and a circulation line that introduces particles separated by the first cyclone and recovers heat to return to the furnace,
The circulation line is provided with at least a first fluidized bed, a second fluidized bed, a third fluidized bed, and a fourth fluidized bed composed of spaces partitioned by a common partition wall;
The first fluidized bed has a particle inlet for introducing particles sent from the lower part of the first cyclone to the upper part of the first fluidized bed space, and one or more air inlets for introducing fluidized air to the lower part. The air supplied from the air introduction port flows through the particle introduction port and flows into the first cyclone,
An opening through which particles of the first fluidized bed flow into the second fluidized bed is provided below the partition walls of the first fluidized bed and the second fluidized bed;
The second fluidized bed comprises one or more air inlets for introducing fluidized air into the lower part of the second fluidized bed space, and an opening for discharging both particles and fluidized air at the upper part, The particles discharged from the opening and the fluidized air have a structure that is returned to the furnace,
An opening through which particles in the lower part of the second fluidized bed flow into the third fluidized bed is provided below the partition walls of the second fluidized bed and the third fluidized bed;
The third fluidized bed comprises one or more air inlets for introducing fluidized air into the lower part of the third fluidized bed space,
An opening for allowing particles of the third fluidized bed to flow into the fourth fluidized bed above the partition walls of the third fluidized bed and the fourth fluidized bed;
The fourth fluidized bed includes an external heat exchanger in which a superheater tube or an evaporator tube of a boiler is immersed in the layer of the fourth fluidized bed,
The lower part of the fourth fluidized bed has a particle outlet for transferring particles in the fourth fluidized bed to a furnace, and has one or more air inlets for introducing fluidized air,
An outlet for discharging fluidized air introduced from the air inlets of the third and fourth fluidized beds is provided above the third fluidized bed;
The circulating fluidized bed boiler apparatus characterized in that the discharge port is connected to a second cyclone, and the air separated by the second cyclone is returned to the furnace.

(Claim 2)
The circulating fluidized bed boiler apparatus according to claim 1, wherein the ash separated by the second cyclone is transferred to the ash silo.

(Claim 3)
A furnace having a fluidized bed, a first cyclone that introduces high-temperature combustion gas from the furnace and collects particles discharged accompanying the combustion gas, and a combustion gas from which particles are separated by the first cyclone In a circulating fluidized bed boiler apparatus comprising: a convection heat transfer section that supplies and generates steam by heat exchange; and a circulation line that introduces particles separated by the first cyclone and recovers heat to return to the furnace,
The circulation line is provided with at least a first fluidized bed, a second fluidized bed, a third fluidized bed, and a fourth fluidized bed composed of spaces partitioned by a common partition wall;
The first fluidized bed has a particle inlet for introducing particles sent from the lower part of the first cyclone to the upper part of the first fluidized bed space, and one or more air inlets for introducing fluidized air to the lower part. The air supplied from the air introduction port flows through the particle introduction port and flows into the first cyclone,
An opening through which particles of the first fluidized bed flow into the second fluidized bed is provided below the partition walls of the first fluidized bed and the second fluidized bed;
The second fluidized bed comprises one or more air inlets for introducing fluidized air into the lower part of the second fluidized bed space,
The lower part of the partition wall of the second fluidized bed and the third fluidized bed has a lower opening through which particles below the second fluidized bed flow into the third fluidized bed, and the upper part of the upper part of the third fluidized bed An upper opening through which fluidized air flows into the second fluidized bed;
The third fluidized bed comprises one or more air inlets for introducing fluidized air into the lower part of the third fluidized bed space,
An opening for allowing particles of the third fluidized bed to flow into the fourth fluidized bed above the partition walls of the third fluidized bed and the fourth fluidized bed;
The fourth fluidized bed includes an external heat exchanger in which a superheater tube or an evaporator tube of a boiler is immersed in the layer of the fourth fluidized bed,
The lower part of the fourth fluidized bed has a particle outlet for transferring the particles in the fourth fluidized bed to a furnace, and has one or more air inlets for introducing fluidized air,
A particle discharge port for discharging particles at the bottom of the second fluidized bed, and the particles discharged from the particle discharge port are returned to the furnace;
The second fluidized bed is provided with a discharge port for discharging the fluidized air in the second, third and fourth fluidized beds, and the discharge port is connected to a second cyclone, A circulating fluidized bed boiler apparatus characterized in that air separated by two cyclones is returned to the furnace.

(Claim 4)
The circulating fluidized bed boiler apparatus according to claim 3, wherein the ash separated by the second cyclone is transferred to the ash silo.

  According to the present invention, by providing the second cyclone, it is possible to provide a circulating fluidized bed boiler apparatus that can solve the problem of high-temperature corrosion in the external heat exchanger and can realize high efficiency of power generation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, based on FIG.1 and FIG.2, 1st Embodiment of the circulating fluidized-bed boiler apparatus which concerns on this invention is described.

  FIG. 1 is a flow diagram showing a first embodiment of a circulating fluidized bed boiler apparatus according to the present invention, and FIG. 2 is a plan view showing an arrangement example of a plurality of fluidized beds in the above embodiment.

  In the figure, reference numeral 1 denotes a furnace having a fluidized bed (dense bed). In the present invention, the structure of the furnace 1 is not particularly limited, but preferably, a dense bed portion 100 having a high superficial velocity is formed at the bottom of the furnace 1 and a furnace main body 101 having a low superficial velocity is formed at the top. Is preferably formed.

  The dense bed unit 100 has a structure capable of supplying waste, auxiliary fuel, combustion air, circulating particles (dense bed material), and the like as a fuel source. When the combustion air is supplied, the dense bed unit 100 The inside is vigorously fluidized and mixed and stirred.

  Wastes include building waste chips, sewage sludge, agricultural and forestry waste, food waste, renewable energy such as RDF (Rufuse Derived Fuel) and industrial waste such as RPF (Rufuse Paper & Plastic Fuel) and waste tires. Can be mentioned.

  As the auxiliary fuel, liquid fuels such as heavy oil and light oil, gaseous fuels such as city gas and propane gas, and solid fuels such as coal may be used, and these auxiliary fuels may use the above-mentioned one type. Two or more kinds can be used in combination. It is also preferable to prepare liquid fuel, gaseous fuel, and solid fuel, respectively, so that they can be switched.

  Combustion air is composed of primary air, secondary air, and the like, and is preheated in advance to increase thermal efficiency.

  The dense bed material mainly plays a role of retaining heat when burning in a fluid state, and for example, gravel, sand, ceramic particles, or the like can be used.

  Circulating solids (particles) are particles that are ejected from the furnace 1, collected by the first cyclone 2, and returned to the furnace 1 again.

  In the dense bed section 100, when the waste, auxiliary fuel, dense bed material, etc. are ignited in a state of being fluidized by the combustion air, they are violently burned and burned at a high temperature, and 850 ° C. to 900 ° C. in the furnace 1. Generates high-temperature combustion gas.

  This high-temperature combustion gas is guided to the first cyclone 2 through the combustion gas duct 102.

  In the first cyclone 2, the particles discharged accompanying the combustion gas are separated. In the present invention, in the process in which the particles separated by the first cyclone 2 are returned to the dense bed part 100 through the circulation line, the first fluidized bed 3, the second fluidized bed 4, the third fluidized bed unique to the present invention. 5 and a fourth fluidized bed 6 are provided.

  The first fluidized bed 3, the second fluidized bed 4, the third fluidized bed 5, and the fourth fluidized bed 6 are basically formed by spaces partitioned by partition walls 300, 400, and 500 that are common to each other.

  The first fluidized bed 3 includes a particle inlet 301 for introducing particles sent from the lower part of the first cyclone 2 in the upper part of the space, and an air inlet 302 for introducing fluidized air in the lower part. A plurality of air inlets 302 may be provided.

  The air supplied from the air inlet 302 into the first fluidized bed 3 flows through the particle inlet 301 and flows into the first cyclone 2.

  With this structure, air blow-up from the lower part of the first cyclone 2 is enabled, and as a result, the particle collection performance in the first cyclone 2 can be controlled.

  The particle collection performance can be controlled by adjusting the amount of air introduced from the air inlet 302.

  According to such blow-up of air, fine particles and corrosive gas (having a small particle size and specific gravity) in the particles rise to the first cyclone 2 and are transported to the convection heat transfer section 8.

  The fine particles having a small particle size include a high temperature corrosion component and cause high temperature corrosion in the external heat exchanger 601 described later. Therefore, if such fine particles and corrosive gas can be discharged in front of the external heat exchanger 601, the cause of high temperature corrosion can be eliminated.

  The fluidizing gas flow rate of the first fluidized bed 3 is specifically in the range of 0.1 to 0.4 m / s in order to blow up the fine particles in the particles collected by the first cyclone 2.

  Moreover, the temperature in the 1st fluidized bed 3 is the range of 850-900 degreeC same as furnace temperature. Therefore, the temperature of the gas blown up to the first cyclone 2 is in the range of about 850 to 900 ° C.

  An opening 303 through which the particles of the first fluidized bed 3 flow into the second fluidized bed 4 is provided below the partition walls 300 of the first fluidized bed 3 and the second fluidized bed 4.

  The second fluidized bed 4 includes an air inlet 401 for introducing fluidized air to the lower part of the space, and an opening 402 for discharging both particles and fluidized air to the furnace 1 at the upper part.

  In this embodiment, since the opening 303 is formed in the lower part of the partition wall 300, particles sent from the first fluidized bed 3 to the second fluidized bed 4 can be removed by the circulating solid and the first fluidized bed 3. Fine particles containing no corrosive components. These particles are discharged from the opening 402 by the fluidized air supplied from the air inlet 401.

  As described above, the second fluidized bed 4 purges (removes) the fine particles containing corrosion components that could not be removed by the first fluidized bed 3, so that it is possible to take measures against high temperature corrosion of the external heat exchanger 601 described later. become.

  The opening 402 is connected to the dense bed 100 of the furnace 1 via a circulation line 403. For this reason, fine particles containing circulating solids and corrosive components are sent to the furnace 1.

  The fluidizing gas flow rate of the second fluidized bed 4 is preferably set in the range of 0.2 to 0.4 m / s in order to form a normal developed fluidized bed. The temperature in the second fluidized bed 4 is in the range of 850 to 900 ° C. which is the same as that of the furnace 1.

  The third fluidized bed 5 includes a fluidized air inlet 501 at the lower part of the space, and an opening 502 for discharging the fluidized air at the upper part.

  Particles sent from the second fluidized bed 4 by holding the tops of the partition walls 500 of the third fluidized bed 5 and the fourth fluidized bed 6 at a position lower than the bottom surface of the opening 402 of the second fluidized bed 4. Is sent from the upper part of the third fluidized bed 5 to the fourth fluidized bed 6.

  In this embodiment, since the particles passing through the lower part of the first fluidized bed 3 and the second fluidized bed 4 are conveyed to the upper part by the third fluidized bed 5, the short circuit of the particles is prevented, and the corrosion is prevented. Purging of particulates including components is further facilitated.

  The fluidizing gas velocity of the third fluidized bed 5 is preferably set in the range of 0.2 to 0.4 m / s in order to form a normal developed fluidized bed. The temperature in the 3rd fluidized bed 5 is the same range as 850-900 degreeC as the furnace 1. FIG.

  The fourth fluidized bed 6 includes an external heat exchanger 601 in the bed. The external heat exchanger 601 preferably has a configuration in which a boiler superheater tube or an evaporation tube is immersed. In order to generate high-temperature and high-pressure steam in this heat exchanger part, the present invention reduces the high-temperature corrosion of these superheater tubes and evaporator tubes.

  An air inlet 602 for introducing fluidized air is provided in the lower part of the space of the fourth fluidized bed 6.

  The fluidized air introduced from the air inlet 602 is discharged from the opening 502 of the third fluidized bed 5 through the opening 604 located at the top of the partition wall 500.

  The discharge port 502 is connected to the second cyclone 7 via a pipe 503, and the air separated by the second cyclone 7 is returned to the furnace 1 via a circulation line 701.

  The ash separated by the second cyclone 7 is transferred to an ash silo 10 to be described later and discharged out of the system.

  Due to such a structure, the fluidized air introduced from the air inlet 602 is transferred to the second cyclone 7 from the upper outlet 502 of the third fluidized bed 5.

  In the fourth fluidized bed 6, the gas temperature is lowered to about 550 to 650 ° C. by the heat exchanger 601, so the particles are not in a molten state and the viscosity is lowered. For this reason, fine particles which are corrosive components and relatively large particles having a high specific gravity are easily separated.

  When fluidized air is introduced from the air inlet 602, fine particles, which are corrosive components, flow upward and can be purged from the outlet 502 to the second cyclone 7.

  In the present invention, when the discharge port 502 at the top of the third fluidized bed 5 is disposed on the side close to the second fluidized bed 4 as shown in FIG. Since the flow of fine particles as the corrosive component transferred to the upper part of the fourth fluidized bed 6 becomes a countercurrent, the purge efficiency of the fine particles as the corrosive component is further improved.

  The fluidizing gas flow rate of the fourth fluidized bed 6 is preferably set to a relatively slow flow rate in order to prevent wear of the immersed heat transfer tubes. Specifically, the fluidizing gas flow rate is 0.2 m / It is preferably set to about s.

  Below the fourth fluidized bed 6, a particle discharge port 603 for transferring the particles after the fine particles in the fourth fluidized bed 6 are separated to the furnace 1 is provided. It returns to the furnace 1 via the line 605 from the particle discharge port 603 to the furnace 1 and is reused as a circulating solid.

  The separated gas (hot combustion gas) and ash discharged from the first cyclone 2 are introduced into the convection heat transfer section 8. In the convection heat transfer section 8, heat is recovered from the separated gas and ash by a heat exchanger. In the present invention, the boiler feed water is heated by the recovered heat.

  Ashes are sent from the convection heat transfer section 8 to the bag filter 9 through the combustion exhaust gas duct 800 and sent to the ash silo 10. The separated gas is discharged out of the system from the bag filter 9 and, for example, exhaust gas treatment is performed.

  Next, based on FIG. 3, 2nd Embodiment of the circulating fluidized bed boiler apparatus which concerns on this invention is described.

  FIG. 3 is a flowchart showing a second embodiment of the circulating fluidized bed boiler apparatus according to the present invention.

  In the following description, a different part from the aspect shown in FIG. 1 is demonstrated especially, and description of a 1st aspect is used for description of the same aspect.

  This mode is different from the first mode in the installation position of the discharge port for discharging the corrosive gas component to the second cyclone 7. This embodiment is different from the first embodiment in that the particle and gas discharge ports 402 in the second fluidized bed 4 are not provided. Furthermore, in this aspect, in accordance with the first aspect and the fact that the discharge port 402 is not provided, a particle circulation line from the second fluidized bed 4 to the furnace 1 is provided at the lower part of the second fluidized bed 4. Is different. Furthermore, this aspect differs from the first aspect in that upper and lower openings are provided in the partition walls 400 of the second fluidized bed 4 and the third fluidized bed 5.

  In FIG. 3, reference numeral 404 denotes a discharge port for discharging fluidized air in the second fluidized bed 4 provided on the upper part of the second fluidized bed 4, and is connected to the second cyclone 7 via a pipe 405.

  With this configuration, the hot corrosion component in the second fluidized bed 4 is sent to the second cyclone 7 and removed. Accordingly, corrosion of the external heat exchanger 601 due to the hot corrosive gas can be prevented.

  Next, in FIG. 3, reference numeral 505 denotes an upper opening through which the fluidized air above the third fluidized bed 5 flows into the second fluidized bed 4 at the upper part of the partition wall 400. The upper opening 505 and the lower opening 504 are formed.

  With this configuration, the hot corrosive gas component contained in the fluidized air above the third fluidized bed 5 flows into the second fluidized bed 4 and is transferred from the outlet 404 to the second cyclone 7 and removed. For this reason, the corrosion prevention effect by the hot corrosive gas of the external heat exchanger 601 is further improved.

  Furthermore, with this configuration, the hot corrosive gas component contained in the fluidized air above the fourth fluidized bed 6 flows into the second fluidized bed 4 via the top of the third fluidized bed 5, and the discharge port 404. To the second cyclone 7 and removed. For this reason, the corrosion prevention effect by the hot corrosive gas of the external heat exchanger 601 is further improved.

  Further, as a factor that can exhibit this effect, the flow of air and particles in the fourth fluidized bed 6 may be countercurrent. The presence of the upper opening 505 contributes to the countercurrent formation.

  In FIG. 3, reference numeral 406 denotes a particle outlet provided in the lower part of the second fluidized bed 4, and the particle outlet 406 is connected to the furnace 1 through a line 605. Therefore, the particles present in the lower part of the second fluidized bed 4 are returned to the furnace 1 from the particle discharge port 406 and can be reused as a circulating solid.

  In the above embodiment, the embodiment including the four fluidized beds of the first fluidized bed 3, the second fluidized bed 4, the third fluidized bed 5, and the fourth fluidized bed 6 has been described, but the fifth fluidized bed is added. It may be an embodiment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by this Example.

Example 1
(Experiment 1)
When the relationship between the corrosion component and the particle diameter was examined by a combustion test using RPF as the fuel, the results shown in Table 1 were obtained. In Table 1, EHE is an abbreviation for external heat exchanger.

  From the results of Table 1, it can be seen that corrosion components such as Cl (chlorine), S (sulfur), and F (fluorine) have a large component ratio of particle diameters (so-called fine particles) of 53 μm or less.

(Experiment 2)
As a result of purging corrosive components by feeding gas from the upper part of the third fluidized bed to the second cyclone using the apparatus shown in FIG. 1, the superheater tube of the external heat exchanger in waste combustion using the fuel used in Experiment 1 The corrosion rate of was investigated.

  The result is shown in FIG.

  In FIG. 4, the horizontal axis represents the chlorine concentration in the fuel, and the vertical axis represents the maximum corrosion depth (mm / year) of the external heat exchanger (material: SUS310S).

  As is apparent from FIG. 4, the corrosion rate of the superheater tube is reduced to 0.5 mm / year or less even at a chlorine concentration of about 1% in the fuel.

(Experiment 3)
The apparatus shown in FIG. 3 was used to purge the corrosive components by sending gas from the upper part of the second fluidized bed to the second cyclone. As a result, the superheater tube of the external heat exchanger in waste combustion using the fuel used in Experiment 1 The corrosion rate of was investigated.

  The result is shown in FIG.

  As is apparent from FIG. 4, the corrosion rate of the superheater tube is reduced to 0.5 mm / year or less even at a chlorine concentration of about 1% in the fuel.

(Comparative Experiment 1)
In Experiment 2, the same experiment was performed using the apparatus shown in FIG. 6, and the corrosion rate was examined. The result is shown in FIG.

(Comparative experiment 2)
In Experiment 2, the same corrosion rate was examined for the case of only the first cyclone without providing the second cyclone in the apparatus shown in FIG. The result is shown in FIG.

Example 2
(Experiment 1)
Using the apparatus shown in FIG. 1, the gas was sent from the upper part of the third fluidized bed to the second cyclone to purge the corrosive components. As a result, the fuel used in Experiment 1 was used. The chlorine concentration was compared with the chlorine concentration in the fuel.

  The result is shown in FIG.

  In FIG. 5, the horizontal axis represents the chlorine concentration in the fuel, and the vertical axis represents the chlorine concentration in the particles of the external heat exchanger (material: SUS310S).

(Experiment 2)
Using the apparatus shown in FIG. 3, gas was sent from the upper part of the second fluidized bed to the second cyclone to purge the corrosive components. As a result, the fuel used in Experiment 1 was used, and the particles in the external heat exchanger in waste combustion The chlorine concentration was compared with the chlorine concentration in the fuel.

  The result is shown in FIG.

(Comparative Experiment 1)
In Experiment 1, the same experiment was performed using the apparatus shown in FIG. 6, and the chlorine concentration in the particles of the external heat exchanger in waste combustion was compared with the chlorine concentration in the fuel.

  The result is shown in FIG.

(Comparative experiment 2)
In Experiment 1, in the case where only the first cyclone is not provided in the apparatus shown in FIG. 1, the chlorine concentration in the particles of the external heat exchanger in the same waste combustion is compared with the chlorine concentration in the fuel. did.

  The result is shown in FIG.

Example 3
In the apparatus shown in FIG. 1, waste mixed with renewable energy such as building waste chips, sewage sludge, agricultural and forestry waste, food waste, RDF, and industrial waste such as RPF and waste tires (chlorine concentration: 1% containing) Fuel was used to conduct corrosion experiments on boiler tubes.

As a result, it was confirmed that high-efficiency power generation with steam pressure: 130 Kg / cm ² G, steam temperature: 570 ° C., and power generation end efficiency: 38% class was possible.

  Further, the superheater corrosion rate was 0.5 mm / year or less, and when pollutants in the exhaust gas were measured, the following results were obtained.

NO _{x <} 100 ppm (O ₂ = 6%)
SO ₂ less than 100 ppm (O ₂ = 6%)
CO less than 50 ppm (O ₂ = 6%)
DXNs less than 0.1 ng / Nm ³

The flowchart which shows 1st Embodiment of the circulating fluidized bed boiler apparatus which concerns on this invention. The top view which shows the example of arrangement | positioning of the some fluidized bed in the form same as the above The flowchart which shows 2nd Embodiment of the circulating fluidized bed boiler apparatus which concerns on this invention. The graph which shows the result of investigating the corrosion rate of the superheater of the external heat exchanger Graph comparing chlorine concentration in particles of external heat exchanger in combustion of waste with chlorine concentration in fuel Flow diagram of conventional circulating fluidized bed boiler equipment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Furnace 100: Dense bed part 101: Furnace main body 102: Combustion gas duct 2: 1st cyclone 3: 1st fluidized bed 303: Opening part 300: Partition wall 301: Particle inlet 302: Air inlet 4: Second flow Layer 400: Partition wall 401: Air introduction port 402: Opening portion 403: Circulation line 404: Discharge port 405: Pipe 406: Particle discharge port 5: Third fluidized bed 500: Partition wall 501: Air introduction port 502: Discharge port 503 : Piping 504: Lower opening 505: Upper opening 6: Fourth fluidized bed 601: External heat exchanger 602: Air inlet 603: Outlet 604: Opening 605: Line 7: Second cyclone 701: Circulation line 8 : Convection heat transfer section 800: Combustion exhaust gas duct 9: Bag filter 10: Ash silo

Claims (4)

A furnace having a fluidized bed, a first cyclone that introduces high-temperature combustion gas from the furnace and collects particles discharged accompanying the combustion gas, and a combustion gas from which particles are separated by the first cyclone In a circulating fluidized bed boiler apparatus comprising: a convection heat transfer section that supplies and generates steam by heat exchange; and a circulation line that introduces particles separated by the first cyclone and recovers heat to return to the furnace,
The circulation line is provided with at least a first fluidized bed, a second fluidized bed, a third fluidized bed, and a fourth fluidized bed composed of spaces partitioned by a common partition wall;
The first fluidized bed has a particle inlet for introducing particles sent from the lower part of the first cyclone to the upper part of the first fluidized bed space, and one or more air inlets for introducing fluidized air to the lower part. The air supplied from the air introduction port flows through the particle introduction port and flows into the first cyclone,
An opening through which particles of the first fluidized bed flow into the second fluidized bed is provided below the partition walls of the first fluidized bed and the second fluidized bed;
The second fluidized bed comprises one or more air inlets for introducing fluidized air into the lower part of the second fluidized bed space, and an opening for discharging both particles and fluidized air at the upper part, The particles discharged from the opening and the fluidized air have a structure that is returned to the furnace,
An opening through which particles in the lower part of the second fluidized bed flow into the third fluidized bed is provided below the partition walls of the second fluidized bed and the third fluidized bed;
The third fluidized bed comprises one or more air inlets for introducing fluidized air into the lower part of the third fluidized bed space,
An opening for allowing particles of the third fluidized bed to flow into the fourth fluidized bed above the partition walls of the third fluidized bed and the fourth fluidized bed;
The fourth fluidized bed includes an external heat exchanger in which a superheater tube or an evaporator tube of a boiler is immersed in the layer of the fourth fluidized bed,
The lower part of the fourth fluidized bed has a particle outlet for transferring particles in the fourth fluidized bed to a furnace, and has one or more air inlets for introducing fluidized air,
An outlet for discharging fluidized air introduced from the air inlets of the third and fourth fluidized beds is provided above the third fluidized bed;
The circulating fluidized bed boiler apparatus characterized in that the discharge port is connected to a second cyclone, and the air separated by the second cyclone is returned to the furnace.   The circulating fluidized bed boiler apparatus according to claim 1, wherein the ash separated by the second cyclone is transferred to the ash silo. A furnace having a fluidized bed, a first cyclone that introduces high-temperature combustion gas from the furnace and collects particles discharged accompanying the combustion gas, and a combustion gas from which particles are separated by the first cyclone In a circulating fluidized bed boiler apparatus comprising: a convection heat transfer section that supplies and generates steam by heat exchange; and a circulation line that introduces particles separated by the first cyclone and recovers heat to return to the furnace,
The circulation line is provided with at least a first fluidized bed, a second fluidized bed, a third fluidized bed, and a fourth fluidized bed composed of spaces partitioned by a common partition wall;
The first fluidized bed has a particle inlet for introducing particles sent from the lower part of the first cyclone to the upper part of the first fluidized bed space, and one or more air inlets for introducing fluidized air to the lower part. The air supplied from the air introduction port flows through the particle introduction port and flows into the first cyclone,
An opening through which particles of the first fluidized bed flow into the second fluidized bed is provided below the partition walls of the first fluidized bed and the second fluidized bed;
The second fluidized bed comprises one or more air inlets for introducing fluidized air into the lower part of the second fluidized bed space,
The lower part of the partition wall of the second fluidized bed and the third fluidized bed has a lower opening through which particles below the second fluidized bed flow into the third fluidized bed, and the upper part of the upper part of the third fluidized bed An upper opening through which fluidized air flows into the second fluidized bed;
The third fluidized bed comprises one or more air inlets for introducing fluidized air into the lower part of the third fluidized bed space,
An opening for allowing particles of the third fluidized bed to flow into the fourth fluidized bed above the partition walls of the third fluidized bed and the fourth fluidized bed;
The fourth fluidized bed includes an external heat exchanger in which a superheater tube or an evaporator tube of a boiler is immersed in the layer of the fourth fluidized bed,
The lower part of the fourth fluidized bed has a particle outlet for transferring the particles in the fourth fluidized bed to a furnace, and has one or more air inlets for introducing fluidized air,
A particle discharge port for discharging particles at the bottom of the second fluidized bed, and the particles discharged from the particle discharge port are returned to the furnace;
The second fluidized bed is provided with a discharge port for discharging the fluidized air in the second, third and fourth fluidized beds, and the discharge port is connected to a second cyclone, A circulating fluidized bed boiler apparatus characterized in that air separated by two cyclones is returned to the furnace. The circulating fluidized bed boiler apparatus according to claim 3, wherein the ash separated by the second cyclone is transferred to the ash silo.

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