JPH0429225Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pulverulent combustion process heating furnace, and more particularly to the structure of a guide hole in a hearth into which a guide rod of a heat exchanger tube is inserted.

[Prior Art] Generally, in a heating furnace in which heat transfer tubes a are arranged vertically along a side wall c of a combustion chamber b, as shown in FIG.
The heat exchanger tube a is fixed at its upper end to the ceiling d of the furnace, and is configured to allow thermal expansion of the heat exchanger tube a that occurs during ignition of the burner e to escape downward. moreover,
For the purpose of restraining the horizontal movement of heat transfer tube a when horizontal force is applied due to an earthquake, etc., a guide rod f is provided extending downward from the lower end of heat transfer tube a, and this guide rod f is also provided on the hearth g. was inserted into the guide hole h. Figure 5 shows the guide hole h.
An enlarged view is shown.

[Problems that the invention aims to solve] By the way, process heating furnaces used in oil refining and petrochemical plants mainly use oil and/or gas as fuel, but in recent years coal, petroleum coke, petroleum coke, Progress has been made in the development of heating furnaces that use fine powder of solid fuels such as charcoal and wood as fuel. It is known that this type of pulverized powder combustion process heating furnace generates a large amount of fine ash during combustion.

Therefore, when pulverized powder combustion is carried out in a process heating furnace equipped with a guide hole h as shown in FIG. . As a result, the movement of the guide rod f inserted into the guide hole h is restricted, and bending stress due to thermal expansion is generated in the heat exchanger tube a, which may cause the heat exchanger tube a to bend or break.

Thus, an object of the present invention is to solve the problems of the above-mentioned prior art and to provide a heating furnace for a pulverulent combustion process that does not cause bending or breakage of heat exchanger tubes while performing pulverulent combustion.

[Means for Solving the Problems] In order to achieve the above object, the pulverized powder combustion process heating furnace of the present invention has heat transfer tubes arranged vertically along the side wall of the combustion chamber maintained in a negative pressure state. In a pulverulent combustion process heating furnace in which the upper end of the heat tube is fixed and a guide rod extending downward from the lower end thereof is inserted into a guide hole of the hearth, the guide rod is provided at the bottom of the guide hole and an air inflow amount adjusting means for causing air to flow into the combustion chamber from outside the furnace and adjusting the amount of air inflow based on a pressure difference between the air inflow and the air; and a sealing member for closing the gap with the upper edge of the guide hole.

[Function] By providing a sealing member on the upper surface of the guide hole, ash generated in the furnace does not easily enter the guide hole.

In addition, in this type of heating furnace, the inside of the combustion chamber is generally kept at a negative pressure (about -2 to _-20 mmH2O) for safety reasons, and by providing an air inflow adjustment means at the bottom of the guide hole, it is possible to easily blow air into the combustion chamber from outside the furnace by utilizing the pressure difference with the atmosphere. As a result, even if ash gets into the guide hole through a gap in the seal member, the air blown in will return the ash to the combustion chamber and it will be discharged from the ash discharge hopper at the bottom of the combustion chamber.

Therefore, clogging of the guide hole with ash is prevented, and the movement of the guide rod is no longer restricted.

[Embodiments] Hereinafter, embodiments of the present invention will be described based on a pulverized coal combustion process heating furnace with reference to the accompanying drawings, but the present invention is not limited to the pulverized coal combustion process heating furnace.

FIG. 1 is a sectional side view of a main part showing a guide hole of a pulverized coal combustion process heating furnace according to an embodiment of the present invention. A guide hole 2 is provided vertically downward in a hearth 1 that is inclined at an angle θ greater than the angle of repose of the ash. Further, a guide rod 4 is provided extending downward from the lower end of the heat transfer tube 3 vertically arranged along the side wall (not shown) of the combustion chamber.
is inserted into the guide hole 2.

A sealing member 5 is provided on the upper surface of the guide hole 2 so as to close the gap between the outer periphery of the guide rod 4 and the upper edge of the guide hole 2. However, a slight gap is formed between this sealing member 5 and the guide rod 4, that is, a small gap is formed between the seal member 5 and the guide rod 4.
is loosely fitted into the seal member 5, and the guide rod 4
It is constructed so that it can move up and down freely. Specifically, the sealing member 5 has two parts as shown in FIG.
It consists of two seal plates 6 and 7, and these seal plates 6 and 7 are joined to each other so that the guide rod 4 is sandwiched therebetween.

Further, at the bottom of the guide hole 2, there is provided an air inflow amount adjusting means 8 for allowing air to flow in from outside the furnace. This air inflow amount adjusting means 8 is connected to the guide hole 2.
It consists of a bottom plate 9 fixed to the bottom of the air conditioner and an air control plate 10 rotatably provided along the bottom plate 9. The bottom plate 9 and the air control plate 10 are connected to each other by a pin 11 at each center, and each has two openings 12 and 13 on one diameter, as shown in FIG. In addition,
The inside of the combustion chamber is maintained at a negative pressure state, and by rotating the air control plate 10 and overlapping the opening 12 of the bottom plate 9 and the opening 13 of the air control plate 10 as shown in FIG. 1, air is removed from outside the furnace. is configured such that it flows into the guide hole 2. Furthermore, air control board 1
By adjusting the rotation angle of 0 and changing the overlapping area of the openings 12 and 13, the amount of air flowing in from outside the furnace is adjusted.

Note that the opening 12 of the bottom plate 9 and the air control plate 1
In this embodiment, the number of openings 13 is set to two, but it is preferable that the number be two or more, since air can be blown into the guide hole 2 more uniformly.

Further, the bottom plate 9 is removable so that the inside of the guide hole 2 can be cleaned.

Guide holes 2 configured as described above are provided at each lower end of the heat exchanger tubes 3 arranged in a meandering manner.

Next, the operation of this embodiment will be described.

First, combustion of pulverized coal is started in the combustion chamber, and a process fluid is introduced into the heat transfer tube 3 to perform heating. At this time, the overlapping amount of the openings 12 and 13 of each air inflow amount adjustment means 8 is set according to the combustion conditions, so that a predetermined amount of air always flows into the combustion chamber from outside the furnace through the guide hole 2. ing.

A large amount of ash is generated in the combustion chamber as a result of this combustion, and a part of it is discharged to the outside of the furnace together with the combustion exhaust gas, but the remainder falls to the hearth 1. The ash that has fallen onto the seal member 5 and the hearth 1 slides on these surfaces and is discharged from an ash discharge hopper (not shown) at the bottom of the combustion chamber.

On the other hand, since a slight gap is formed between the seal member 5 and the guide rod 4, some ash may fall into this gap. However, since the air is blown into the combustion chamber from this gap through the air inflow amount adjusting means 8 and the guide hole 2, the ash is returned to the combustion chamber.

In this way, clogging of the guide hole 2 with ash is prevented.

Further, as the heat exchanger tube 3 burns, its temperature rises and thermally expands. The heat exchanger tube 3 is fixed at its upper end to the ceiling of the combustion chamber, and the guide rod 4 moves downward by the amount of thermal expansion of the heat exchanger tube 3. At this time, since the guide hole 2 is not clogged with ash as described above, the movement of the guide rod 4 is not restricted, and therefore there is no possibility that the heat exchanger tube 3 will be bent or broken.

[Effects of the invention] As explained above, according to the present invention, the following excellent effects are achieved.

(1) Even when pulverized powder combustion is performed, ash does not enter the guide hole and clog it, so the movement of the guide rod is not restricted.

(2) Therefore, there is no fear that the heat exchanger tubes will be bent or destroyed due to thermal expansion, improving safety.

(3) Since the amount of air flowing in from outside the furnace can be adjusted, this air inflow will not affect combustion by allowing the air to flow in according to the combustion conditions.

(4) Since the differential pressure between the inside and outside of the furnace is used, the atmospheric inflow amount adjusting means can be configured with an extremely simple structure.

[Brief explanation of drawings]

FIG. 1 is a sectional side view of a main part showing a guide hole of a pulverized coal combustion process heating furnace according to an embodiment of the present invention, and FIGS. The plan view, FIG. 4, and FIG. 5 shown are a side view and an enlarged view of essential parts of a conventional heating furnace, respectively. In the figure, 2 is a guide hole, 3 is a heat exchanger tube, 4 is a guide rod, 5 is a sealing member, and 8 is an air inflow rate adjusting means.

Claims (1)

[Scope of utility model registration request] A heat exchanger tube is vertically arranged along the side wall of the combustion chamber which is maintained under negative pressure, and the upper end of the heat exchanger tube is fixed and a guide rod extending downward from the lower end serves as a guide for the hearth. In a pulverulent combustion process heating furnace inserted into a hole, an atmospheric air valve is provided at the bottom of the guide hole and is used to cause atmospheric air to flow into the combustion chamber from outside the furnace and to adjust the amount of air flowing into the combustion chamber based on a pressure difference with the atmospheric air. A pulverulent combustion process characterized by comprising: an inflow amount adjusting means; and a sealing member provided on the upper surface of the guide hole and closing a gap between the outer circumference of the guide rod and the upper edge of the guide hole. heating furnace.