JPH0719413A - Apparatus and method for monitoring deterioration of fluid material of fluidized-bed furnace - Google Patents

Abstract

PURPOSE:To previously sense deterioration of a fluid material by injecting cooling gas to an upper surface of a horizontal heat resisting glass plate provided on a lower part in a fluidized bed, continuously replacing the material on a periphery of an upper part of the plate, and continuously displaying a shape change of a particle size of the material at a present time by a condensing lens and an image detector. CONSTITUTION:A fluid material shape detector having an inner tube 41 and an outer tube 42 is inserted into a fluid material 12, and connected to a controller for processing an image and calculating via a cable. A sapphirine heat resisting glass plate 43 having a small spectral polarization is inserted into an upper part of the tube 41 and condensing lenses 44a, 44b are inserted under the plate 43 by sealing it to an inner surface of the tube 41. Further, An image detector is provided thereunder. Cooling gas 45 is fed in a direction of an arrow, injected from nozzle ports 46a-46c to the plate 43, the lenses 44a, 44b to cool them, the material on the plate 43 is scattered to a periphery, and images of particle shapes are obtained via the lenses 44a, 44b and displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed combustion apparatus, and more particularly to an apparatus and method for monitoring deterioration of fluidized materials in a heating furnace, a combustion furnace and the like using a fluidized bed form.

[0002]

2. Description of the Related Art In combustion in a fluidized bed, a certain amount of particles (referred to as fluidized material) are put into a fluidized bed combustor (vertical tower) in a fixed amount and stored, and gas is aerated from below to store the flow rate. Increase. Then, the particles are blown up, the space between the particles becomes large, and they fall again. When the air volume is further increased, the vertical movement of the particles becomes more intense,
Around the many bubbles, particles flow down to fill the traces of the bubbles to form a fluidized bed. The fluidized bed combustion method using such a fluidized bed configuration has a uniform temperature in the fluidized bed and a large heat transfer coefficient. Therefore, by inserting a heating element such as various reaction tubes into the fluidized bed, local heat It is useful as a lossless uniform heating method.

FIG. 6 is a diagram showing an example of a conventional fluidized bed furnace. In this figure, a fluid material (12) having a constant particle diameter is previously charged into the combustion furnace (11). Also blower (1
From 4), combustion air passes through the blower pipe (15), the plenum chamber (16), the perforated plate (17), and then the combustion furnace (1
It is sent to 1) to form a fluidized bed. A heat transfer tube (13) in which the heating medium is flowing is inserted and mounted in the fluidized bed.

On the other hand, oil fuel or the like and air sent from a supply facility (not shown) are combusted in a high temperature gas generating furnace (18), and the generated high temperature gas is used as in the plenum chamber (1).
Send to 6). As a result, the fluidized material (12) is heated above the ignition temperature of the fuel such as coal, and then the solid fuel such as coal is supplied from the fuel storage hopper (19a) to the feeder (19b) and the supply pipe (19c).
When the fluid is supplied into the fluid material (12) via, the self-combustion starts.
Then, the fluid material (12) is further heated to a higher temperature, so that the feeding of the high temperature gas from the high temperature gas generating furnace (18) is stopped. In this state, the calorific value from the fuel and the heat transfer tube (1
By adjusting the heat absorption amount of 3), the fluid material is always maintained at a constant appropriate temperature. Further, the combustion exhaust gas is discharged out of the system through the exhaust gas duct (20) and the dust collector (21).

[0005]

The above conventional fluidized bed furnace has the following problems to be solved.

The coal particles charged into the furnace move to the combustion of the particle surface after the volatile matter is released. During the initial release of volatile matter, the surface of the coal particles is blocked from oxygen and does not burn, so the surface temperature is lower than the fluidized bed temperature.However, during the subsequent surface combustion, the heat generated on the particle surface is radiated and fluidized. Heat is released by contact between particles and convection to the surrounding gas,
When the heat generation rate is higher than the heat release rate, the particle temperature during surface combustion becomes higher than the fluidized bed temperature.

On the other hand, when the fluidized bed morphology is bad and the fluidized material particles are not fluidized, or when coal having a low ash melting point is used as a fuel,
Alternatively, when the inside of the combustion furnace is pressurized, the surface temperature of the coal particles becomes higher than the softening temperature of the low melting point compound composed of Ca, Fe, S, Na, K contained in the coal ash. Then, a locally melted portion is generated on the surface of the particle, and that portion becomes a binder to start adhesion of particles to each other, so-called agglomeration (particle aggregation) phenomenon occurs. Due to such agglomeration of particles, the apparent particle size is increased, and the fluidized form is further deteriorated, and eventually fluidized bed combustion cannot be maintained and an emergency operation is stopped.

[0008]

In order to solve the above-mentioned conventional problems, the present invention provides a heat-resistant glass plate installed in the lower part of the fluidized bed and horizontally provided at the upper end, and a lower part of the heat-resistant glass plate. A fluidized-bed deterioration monitoring device for a fluidized-bed furnace, comprising: a condenser lens and an image detector provided on the upper surface of the heat-resistant glass plate; and means for injecting a cooling gas onto the upper surface of the heat-resistant glass plate; Determine the heat transfer amount from the fluidized bed to the fluid by measuring the inlet and outlet temperature and the flow rate of the fluid flowing through the heat transfer tube, further determine the heat transfer coefficient on the fluidized bed side by measuring the temperature of the fluidized bed, A method for monitoring deterioration of fluidized material in a fluidized bed furnace characterized by detecting deterioration of fluidized material based on the temporal change of the heat transfer coefficient; and measuring a pressure difference between two different heights in the fluidized bed However, the deterioration of the fluid material can be detected based on the time change of the pressure difference. Flowing material deterioration monitoring method of the fluidized bed furnace, characterized in proposes a.

[0009]

In the first solution, the cooling gas is injected onto the upper surface of the horizontal heat-resistant glass plate arranged in the lower part of the fluidized bed, so that the fluid material around the upper part of the heat-resistant glass plate is It will always be continuously replaced by force.
Then, the current shape change of the particle size of the fluid material can be continuously displayed on the outside image processing device or the like via the condenser lens and the image detector. Therefore, the occurrence / progress of agglomeration phenomenon and operation troubles can be predicted, and the operator determines in advance the safe operation control and operation stop of the fluidized bed combustion device, which leads to deterioration of the fluidized bed form and abnormal combustion due to the use of low melting point coal. Driving status information can be given quickly and continuously.

When the agglomeration phenomenon described above occurs, the fluid material in the fluidized bed has a coarser particle diameter than that of an appropriate particle diameter at the initial stage of charging, and the particle diameter or the number of coarse particles gradually increases. Along with this, the weight of the coarse particles increases, and the fluidization phenomenon decreases, and the particles settle down and aggregate in the lower part of the fluidized bed. Therefore, in a place where there are many coarse particles, the heat transfer coefficient in the fluidized bed decreases and the pressure loss in the heightwise direction of the fluidized bed changes.

In the second and third means for solving the problems, the pressure difference between two points having different heat transfer rates or heights in the lower part of the fluidized bed is continuously or intermittently measured, and the agglomeration phenomenon is observed from the changing state of the numerical values. Occurrence of (degradation of fluid material) and its speed are jointly predicted by the operator. As a result, some of the coarse particles can be extracted from the lower part to the outside of the system to avoid operating troubles, or preventive measures such as changing operating conditions can be taken to avoid an emergency stop of the fluidized bed combustion device. it can.

[0012]

1 is a view showing a fluidized bed furnace to which an embodiment of the present invention is applied, FIG. 2 is a longitudinal sectional view showing a main part of a fluidized material deterioration monitoring device of the embodiment, and FIG. III-III horizontal sectional view,
FIG. 4 is a horizontal sectional view taken along the line IV-IV in FIG. In these figures, the same parts as those of the conventional one described with reference to FIG. 5 are given the same reference numerals to avoid redundancy, and detailed description thereof is omitted.

In this embodiment, a fluid material shape detector (22) is inserted in the fluid material (12), and a signal obtained from the fluid material shape detector (22) is subjected to image processing and calculation by a cable (23). (24) and is connected to an operation control system of an image display device or a fluidized bed combustion device (not shown). When deterioration of the fluidized bed configuration due to agglomeration is predicted, a control signal is sent to a heating medium flow rate control device (not shown) or a fuel supply control device, and the flow rate of the heating medium flowing in the heat transfer tube (13) is increased. , Or by reducing the amount of fuel supplied from the supply pipe (19c) to lower the temperature of the fluidized bed, avoiding an emergency stop of the fluidized bed combustor and continuing stable operation. Can let the operator know in advance whether or not it is necessary to change the property of fuel.

2 to 4, the fluid material shape detector comprises an inner tube (41) and an outer tube (42), and the upper tube of the inner tube (41) is made of a sapphire heat-resistant glass plate having a small spectral polarization. (43) and a condenser lens (44
A) and (44b) are inserted and sealed between the inner surfaces of the inner pipe (41). An image detector (not shown) is provided further below. Further, when the cooling gas (45) supplied from the direction of the arrow below the inner pipe (41) passes through the nozzle openings (46a), (46b), (46c) on the side wall of the inner pipe (41), Four
1), the outer tube (42), the heat-resistant glass plate (43) and the condenser lenses (44a), (44b) are cooled. This cooling gas (4
5) scatters the fluid material on the upper surface of the heat-resistant glass plate (43) to the surroundings when ejecting from the nozzle port (46c) into the fluidized bed (12). As a result, the fluid material on the heat-resistant glass plate (43) is always replaced. Condensing lens (44a), (44b)
The image of the particle shape obtained in 1. is taken out of the system as a signal of the number of particles per unit time and the particle diameter through an image detector such as a thermoscope or photo sensor (not shown), and information is displayed to the operator by an image display. It is provided as well as further connected to the control device of the fluidized bed combustion device and used as an operation control signal for judging deterioration of the fluid material from the amount of change per unit time.

Next, FIG. 5 is a view showing a fluidized bed furnace in which a second embodiment of the present invention is carried out. Also in this figure, the same parts as those described above are designated by the same reference numerals, and detailed description thereof will be omitted.

In the present embodiment, a heat transfer tube (31) separate from the heat transfer tube (13) for utilizing heat in the fluidized bed (12).
Is installed, the flow rate W of the heating medium flowing in the heat transfer tube (31), the inlet temperature T _A, and the outlet temperature T after heating.
_B is measured. Further, since the heat transfer area A in contact with the fluidized bed (12), the heat transfer tube wall thickness d, the heat conductivity λ and the heat transfer coefficient α _A on the heating medium side can be easily obtained by measurement or desktop calculation, the heat transfer tube ( 31) The average heat transfer coefficient α _B in the surrounding fluidized bed can be calculated as follows.

Heat is transferred from the fluidized bed to the heating medium in the heat transfer tube inserted into the fluidized bed by the formula [1].

[0018]

[Equation 1]

Therefore, W, C _p , T _A and T _B are given to obtain the heat transfer amount Q from the above equation (1), and then t _A , t _B and A are given to obtain K from the equation (2). . Further, by giving α _A , d, and λ to the equation (3), the heat transfer coefficient α _B on the fluidized bed side is calculated.

On the other hand, in this embodiment, pressure take-out pipes (32a), (32b) are provided at two points in the fluidized bed whose heights differ by H.
A pressure difference ΔP introduced from the pressure take-out pipes (32a) and (32b) is measured by a differential pressure gauge (32). This differential pressure ΔP is given by the equation [2].

[0021]

[Equation 2]

Since the height difference H is measured in advance, based on the differential pressure ΔP in the fluidized bed obtained by the differential pressure gauge (32),
The bulk density ρ _{B of the} fluidized material in the fluidized bed is calculated by the formula [2]. When the agglomeration phenomenon of the fluidized material occurs in the fluidized bed as described above, both the fluidized bed side heat transfer coefficient α _B and the fluidized material bulk density ρ _B in the fluidized bed, which are obtained by the above calculation, decrease. Therefore, it is possible to inform the operator of the presence / absence of the agglomeration phenomenon and the judgment information of the traveling speed from these changes with time. Then, coarse particles can be extracted from the lower part of the fluidized bed to the outside of the system to avoid operating troubles, or countermeasures for changing operating conditions can be taken to avoid an emergency stop of the fluidized bed combustor.

[0023]

According to the present invention, the particle size and bulk density of a fluid material in a fluidized bed combustion furnace or the change over time in the heat transfer coefficient in the fluidized bed are obtained, and based on this, particle agglomeration (agglomeration) of the fluid material is obtained. ) It is possible to accurately know the occurrence and progress of phenomena and the increase in coarse particles. In addition, it is possible to detect in advance that the fluidized bed form is poor and the fluidization of the fluid material particles becomes inactive, so troubles such as emergency stop can be avoided by taking measures for driving operation measures to avoid troubles, and stable combustion You can keep driving.

[Brief description of drawings]

FIG. 1 is a diagram showing a fluidized bed furnace to which a first embodiment of the present invention is applied.

FIG. 2 is a vertical cross-sectional view showing a main part of the fluid material deterioration monitoring device of the above embodiment.

FIG. 3 is a horizontal sectional view taken along the line III-III in FIG.

FIG. 4 is a horizontal sectional view taken along the line IV-IV of FIG.

FIG. 5 is a diagram showing a fluidized bed furnace in which a second embodiment of the present invention is implemented.

FIG. 6 is a diagram showing an example of a conventional fluidized bed furnace.

[Explanation of symbols]

 (11) Combustion furnace (12) Fluid material (13) Heat transfer tube (14) Blower (15) Air supply tube (16) Plenum chamber (17) Perforated plate (18) High temperature gas generation furnace (19a) Storage hopper (19b) Supply Container (19c) Supply pipe (20) Exhaust gas duct (21) Dust collector (22) Fluid material shape detector (23) Cable (24) Controller (31) Heat transfer pipe (32a), (32b) Pressure extraction pipe (32) Differential pressure gauge (41) Inner tube (42) Outer tube (43) Heat-resistant glass plate (44a), (44b) Condensing lens (45) Cooling gas (46a), (46b), (46c) Nozzle mouth

Claims (3)

[Claims] 1. A heat-resistant glass plate installed in the lower part of the fluidized bed and horizontally provided at the upper end, a condenser lens and an image detector provided below the heat-resistant glass plate, and the heat-resistant glass plate. A fluidized material deterioration monitoring device for a fluidized bed furnace, comprising: a means for injecting a cooling gas on the upper surface. 2. The heat transfer amount from the fluidized bed to the fluid is obtained by measuring the inlet / outlet temperature and the flow rate of the fluid flowing in the heat transfer tube arranged in the fluidized bed, and the temperature of the fluidized bed is further measured to cause the fluidization. A method for monitoring deterioration of a fluidized material of a fluidized bed furnace, which comprises: determining a heat transfer coefficient on the floor side and detecting deterioration of the fluidized material based on a temporal change of the heat transfer coefficient. 3. A fluidized bed furnace flow characterized by measuring a pressure difference between two points having different heights in the fluidized bed and detecting deterioration of the fluidized material based on a temporal change of the pressure difference. Material deterioration monitoring method.