JPS58213107A - Automtic ash discharging device for fluidized bed - Google Patents

Abstract

PURPOSE:To easily control discharge of ashes by opening and closing a motor- operated valve in an air jet pipe, by a method wherein an ash discharge pipe connected to an under surface of a fluidized bed has an intermediate part bent in a V-shape, and the air jet pipe is linked to said bent part. CONSTITUTION:A coal burning fluidized bed type boiler 6 is constituted such that coal is charged into a fluidized bed 8 through a charging port 10, and the fluidized bed 8 is formed on an air dispersion plate 1 partitioning wind box 9 positioned at the lower part of the boiler. In which case, an ash discharge pipe 11 is connected in a downward manner to the air dispersion plate 1, the discharge pipe 11 is bent in an about V-shape outside the boiler 6, and is connected to an ash box 5 mounted on the side of the boiler 6. An air pipe 12 is coupled to the bent part of the ash discharge pipe 11, and a motor-operated valve 13 is situated on the pipe 12. With the motor-operated valve 13 opened when the worsening fluid state of the fluidized layer 8 is detected, a high pressure air is jetted through the jet pipe 12 to pneumatically convey the ashes through the ash discharge pipe 11 to the ash box 5.

Description

Detailed Description of the Invention The present invention relates to a device for automatically discharging ash produced in the fluidized bed of a fluidized bed boiler to the outside of the bed, and is particularly applicable to a coal-fired fluidized bed boiler. The present invention relates to an effective fluidized bed automatic ash ejector.

Usually, coal-fired fluidized bed boilers use pulverized coal with a high ash content, low grade (ash content 30~!θ%), and large particle size due to fuel availability and cost issues, or problems with the thinness of the pulverized membrane and the cost. In many cases, it is necessary to adapt to the use of ash (with a particle size of about 5 mm), but when such low-rank coal is burned in a fluidized bed, large-sized ash (particle size Large pieces of coal debris (so-called burnt coal debris) accumulate and the flow condition worsens.

As a result, heat transfer within the layer deteriorates, the temperature within the layer increases, and the concentration of nitrogen oxides and sulfur oxides in the exhaust gas increases. Generally, the temperature inside the layer is about ♂! cPC
When the temperature exceeds this level, when in-furnace desulfurization is performed by adding a desulfurizing agent, the desulfurization rate rapidly decreases and sulfur oxides increase.

Therefore, in order to maintain a good fluidity M, it is necessary to extract such ash having a large particle size.

In addition, in order to maintain an appropriate bed height of the fluidized bed, it is necessary to extract the ash.

A conventional ash evacuation device used for this purpose is shown in FIGS. 2 and 43. In Fig. 2, automatic valves 3 and 3 are installed in the ash discharge pipe connected to the lower part of the air distribution plate 1, and the automatic valve 3 is first fully opened, and the ash is discharged between the automatic valve 3 and the automatic valve 1. This is a method in which the ash is collected, the automatic valve 3 is closed, the automatic valve Z is opened, and the ash is put in the box at the end of the box, and this operation is repeated once the required amount has been discharged. In addition, B is a coal-fired fluidized bed boiler, 7 is a boiler evaporation pipe, ♂ is a fluidized bed, 2 is a wind box, and 10 is a coal input port. In Figure 3, only seven automatic valves 3 are provided in the middle of the discharge pipe 2, and only when the automatic valves 3 are open are the ash in the layer removed? Let's talk about how to stop the discharge by closing it. Each of these conventional ejection devices has the following drawbacks. In other words, (1) When receiving large particle size coal (approximately 2 nm), such as in a packaged coal-fired fluidized bed boiler, the discharge pipe must be at least It is necessary to use a pipe that is three times the particle diameter (7jφmm) or more, and the size of the automatic valve (or valve) that controls the discharge amount becomes large and expensive. Instantaneous emissions tend to be excessive, making it difficult to control emissions.

(2) The temperature of the discharged ash is the same as the temperature inside the soil layer (about Cθ0C), and an automatic valve (or valve) that can withstand such high temperatures is required.
It is essential to use a powder valve with a heat resistance of 0°C or higher.Moreover, in the case of the valve shown in Fig. 3, the instantaneous discharge amount is large, so in order to improve the controllability of the discharge amount, the valve is closed from the opening of the valve. A valve with a short closing time is required. In addition, since it is a valve for powder and granular materials, an automatic valve with high torque that can withstand even slight clogging is required.

Mechanism (or valve) for pharyngeal bodies that satisfies all of the above specifications
does not yet exist as a product, and in fact, we are currently using valves with insufficient specifications.
Naturally, this can easily cause trouble. Furthermore, (3) In order to ensure smooth discharge, the ceiling discharge pipe should be installed vertically or at an angle close to vertical (not -1', and between the pipes, there should be a free 7PC or valve with a large diameter). You must install 7 or 2 of them, and all the boxes must be placed under them. For this reason, it is necessary to increase the distance from the wind box at the bottom of the fluidized bed to the floor, which increases the height of the boiler. Therefore, this is a big bottleneck for boilers such as package boilers, which are often installed in the same building and cannot take up space in the height direction due to height restrictions on cypress feeders.

The present invention has been made in view of the above-mentioned drawbacks of the conventional apparatus, and its objectives are (1) to easily and easily control the discharge of ash by using high-pressure air, and to control the particle size of the coal used. Perform control in response to changes in properties.

B) Achieved shortening of the distance from the bottom of the fluidized bed to the floor surface 1,
To reduce the overall height of a boiler to reduce its manufacturing cost, construction cost of an auxiliary building, or transportation cost thereof.

(3) To realize a configuration in which the installation location of the receiving box can be freely set in 8 relationships with the boiler position.

(4) By completely abolishing the expensive automatic valve attached to the ash discharge pipe in conventional equipment, costs can be reduced and troubles can be prevented.

(5) To realize a device that allows ash with relatively small particle size to remain in the fluidized bed and discharge only ash with relatively large particle size.

(6) To realize a device that cools the ash to be discharged during the discharge, thereby lowering the heat resistance of incoming sound compared to conventional devices.

It is in.

As a means for achieving the above-mentioned object, the present invention has provided that a discharge pipe for drawing out ash from the lower surface of a fluidized bed in the direction of gravity and guiding it to an input box is bent in the middle to form a wedge-shaped pipe. An air outlet pipe for pressurizing high-pressure air from the outside is connected to the bent part of the exhaust pipe, and the air outlet pipe has an electric valve for air control or a solenoid valve for air control on its upstream side. The valve is configured to be opened or closed by detecting an increase in the differential pressure of the bed member in the fluidized bed, an abnormality in the temperature in the bed, or the extended operation time.

Next, the configuration of the apparatus of the present invention will be explained in detail below with reference to FIG. 1 showing an embodiment. ), the same reference numerals as those in Figures Z2 and 3 indicate the same members.

1/ is the ash discharge pipe, which is taken out downward from the air distribution plate 1, and has a square shape at the point where it is taken out, and is placed in a box installed next to the fluidized bed boiler 2! Piping to.

Further, as shown in the figure, the air jet pipe /2 is operated with respect to the bent portion in a box shape, and the air control electric valve /3 is installed on the upstream side of the air jet pipe /2. Electric valve for air control/
3 may use a solenoid valve depending on the case.

The air control electric valve/3 is opened/closed by detecting an increase in the differential pressure of the bed material, an abnormality in the bed temperature indicating deterioration of the flow state, or the total number of hours of operation. When air control electric valve /3 opens, high pressure air from / to 2- is discharged from the exhaust pipe //
The ash that has accumulated at the bottom of the sign is air-transported into the box j. At this time, at the same time as the air control motorized valve 3, the air vent motorized valve installed at the top of the box is also opened, and in order to keep the pressure in the ash 1 low, the air containing fine powder in the ash is removed from the air vent pipe. ! It is then sent to a dust collector.

At this time, some air ejected from the air control electric valve 3 causes a flow inside the fluidized bed inside the air dispersion plate/discharge pipe l/ up to the bottom of the mustard shape. Therefore, ash with a relatively small particle size does not fall along the discharge pipe ///C, and only ash with a large particle size falls into the discharge pipe ///C, making it possible to selectively discharge only ash with a large particle size.

On the other hand, the required amount of ash has been discharged, and the electric valve for air control / 3
When the air distribution system is closed and the entire air supply is stopped, the transportation of ash by the air stops, and the inside of the discharge pipe between the outlet of the air distribution plate and the bottom of the square becomes a fixed layer of ash, while the inside of the discharge pipe between the outlet of the air distribution plate and the bottom of the square The inside of the discharge pipe between the bottom and the end of the box is empty. At the same time, the air vent motor operated valve l is closed. Therefore, if it is necessary to fully open the box during the boiler operation, it is recommended to install a manual valve in the empty part of the discharge pipe that is closed only when opening the box. ) It becomes possible to peel off from the flat surface on top of the indentation.

This inventive device is constructed as described above, and therefore: (1) Ash discharge can be easily controlled by simply closing the air control electric valve, and the discharge amount can be controlled by changing the opening/closing timing or changing the air pressure. This can be handled with simple changes such as these, and it has become possible to immediately control changes in coal particle size and pouring shape.

(2) Since the distance from the bottom of the fluidized bed to the floor can be significantly shortened, the height of the entire boiler can also be significantly reduced. This made it possible to reduce the manufacturing cost of the boiler. In addition, in the case of boilers designed for indoor installation, the height of the boiler room can be lowered, making it possible to reduce construction costs. It also reduced transportation costs.

(3) The installation location of the receiving box is no longer limited to the space below the fluidized bed and can be installed horizontally, and the capacity and shape of the receiving box are increased, allowing the ash It is now possible to design boxes that take into account the appropriate frequency of transportation to the bunker.

(4) In order to have a valve at the bend of the ash discharge pipe and control it with an electric valve for air control, an automatic valve (or YF), which is flat and has insufficient specifications, is installed in the ash discharge pipe. Since there is no need to use it at all, costs are significantly reduced and troubles do not occur.

(5) An air flow is created in the ash discharge pipe in the opposite direction to the ash discharge direction, preventing ash with small particle size from being discharged, and making it possible to sort and grind only ash with large particle size, making it more efficient. This makes it possible to discharge ash.

(6) Since the ejected ash is simultaneously cooled while being transported by air, it has become possible to lower the heat resistance of the box than in the case of the conventional method.

It exhibits unique effects such as

[Brief explanation of drawings]

Figure 1 is a front view of the device of the present invention, and Figures 2 and 3 are cross-sectional views showing different examples of conventional devices. /01. air distribution plate, 2. //,, Ash discharge pipe, 3°g06. Automatic valve, evening 01. Haikan, Otsu 000 stone fire fluidized bed boiler, 710. Boiler evaporation tube, ♂09. Fluidized bed? ,
,, Wind Box, 10. , , stone input port , /, 2 , , ,
Air jet pipe, /3. ,,Electric valve for air control,/g11.
Air vent electric valve, / evening 10. Air vent tube. Kawasaki Heavy Industries, Ltd., Tosan no Gyo-7-M

Claims (1)

[Claims] The discharge pipe for drawing out the ash from the bottom surface of the fluidized bed in the direction of gravity and guiding it into the box is bent in the middle to form a dog-shaped pipe, and the entire air jet pipe for fully injecting high-pressure air from the outside is used. Connected to the bent part of the discharge pipe, the air jet pipe has an air control electric valve or an air control solenoid valve interposed on its upstream side, and the valve is used to increase the differential pressure of the bed material in the fluidized bed or A fluidized bed automatic ash discharging device characterized in that the associated opening/closing is performed by detecting an abnormality in internal temperature or the total number of hours of operation.