JPH0464889A - Fluidized bed device - Google Patents

Abstract

PURPOSE:To permit the simplification of the structure of a gas dispersing unit and supply gas fuel into a fluidized bed surely by dispersing it by a method wherein a plurality of air pipes, whose one end is fixed to the bottom of a furnace and the other end of the same is free, are provided in parallel with an equal interval while a multitude of air dispersing pipes, projected upwardly into respective axial directions with an equal interval, are provided. CONSTITUTION:A gas dispersing unit 20 is provided on the bottom 10a of a furnace body 10 in a fluidizing chamber 70 while a plurality (four stages in upand-down in this embodiment) of heat transfer tubes or catalyst tubes 80 are arranged in the arrangement of up-and-down in the fluidizing chamber 70 above the catalyst tubes 80 across the fluidizing chamber 70 with a predetermined distance between the gas dispersing unit 20. The gas dispersing unit 20 and the upper position by a predetermined height are filled with fluidized medium when the title device is not operated. A combustion exhaust gas take-out tube 90 is attached to a free port 70a above the fluidizing chamber 70. An exhaust gas discharging pipe 90a is attached to the combustion exhaust gas take-out tube 90. Upon preheating, the fluidized medium positioned above the air injection port of air dispersing pipes, is fluidized, however, the fluidized medium, positioned at the lower part of the air injection port and occupying a part around the injection port of gas fuel, is not fluidized and said fluidized medium forms a resting bed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluidized bed apparatus such as a fluidized bed reforming furnace, and particularly to a fluidized bed apparatus with an improved structure of a gas dispersion section.

[Conventional technology]

Conventionally, the gas dispersion section of a fluidized bed apparatus such as a fluidized bed reforming furnace has often been in the form of a gas dispersion plate, as shown in, for example, Japanese Unexamined Patent Publication No. 1-290502. This gas distribution plate is constructed by, for example, attaching a partition plate across the furnace and attaching a large number of gas distribution pipes to the partition plate, thereby dividing the air chamber and the flow chamber located at the lower part. Then, high-temperature gas (air) is supplied from the air chamber into the fluidization chamber through a large number of gas distribution tubes of the gas distribution plate, a fluidized bed is formed in the fluidization chamber, and gas fuel, etc. is fluidized and combusted in the fluidized bed. Note that a cooling pipe may be attached to the gas distribution plate.

In addition, in a fluidized bed reforming furnace, the gas fuel to be burned in the fluidized bed is supplied from the gas fuel supply passage formed between the upper and lower partition plates in the gas distribution plate into the gas distribution pipe drilled on the side wall of the gas distribution pipe. The fuel is taken into the fuel inlet and introduced into the flow chamber together with the high temperature gas introduced from the air chamber by the gas distribution pipe.

[Problem to be solved by the invention]

For example, in the case of the above-mentioned distribution plate type, the temperature of the fluidized bed is 9
Since the temperature is about 00°C, it is exposed to a high temperature atmosphere and has a large thermal expansion. Therefore, the mechanism for absorbing thermal elongation becomes complicated. For example, it is necessary to attach a cooling device such as a water cooling pipe. Furthermore, it is difficult to seal the air chamber and the flow chamber.

In addition, as described above, in the structure in which gas fuel is supplied from the fuel passage of the gas distribution plate through the gas fuel inlet of the distribution tube, gas fuel is not supplied when the fluidized bed is preheated at the time of starting the fluidized bed apparatus, and the gas fuel is heated to a high temperature. Only air is supplied, but in this case, there is a risk that high-temperature air may flow backwards into the gas fuel pipe, and when gas fuel is supplied, it may burn within the gas distribution plate, resulting in an abnormally high temperature that may damage the distribution plate. be.

In addition, since high temperature air and gas fuel are introduced into the fluidization chamber from the same location, the gas fuel may not be sufficiently distributed throughout the fluidized bed, and the mixing of the fluidization medium and gas fuel may not be as good as expected. , combustion is not performed sufficiently and gaseous fuel tends to escape to the freeboard section.

The present invention has been made in view of these problems, and provides a gas dispersion section that can be easily constructed without requiring any special considerations regarding elongation due to heat or the sealing mechanism between the upper and lower chambers of the gas dispersion section. The object of the present invention is to provide a fluidized bed apparatus that can reliably disperse and supply gaseous fuel into a fluidized bed.

[Means to solve the problem]

In order to achieve the above object, the present invention provides: (1) A plurality of air pipes are provided at the bottom of the furnace, one end of which is fixed to the furnace and the other end of which is free, arranged in parallel at approximately equal intervals; This fluidized bed apparatus is provided with a large number of air dispersion tubes projecting upward from the air tube at approximately equal intervals in the axial direction of the air tube. (2) At the bottom of the furnace, a plurality of air pipes with one end fixed to the furnace and the other end free are arranged side by side at approximately equal intervals, and the air pipes are arranged at approximately equal intervals in the axial direction of each air pipe. A large number of air dispersion pipes are provided that protrude upward from the air pipe, and a plurality of gas fuel pipes are provided above the air pipe, approximately parallel to the air pipe, with one end fixed to the furnace and the other end free. The fluidized bed apparatus is provided with a large number of gas fuel dispersion pipes arranged in parallel at equal intervals, located between the air dispersion pipes, and protruding downward from the gas fuel pipes. Furthermore, (3)
This is a fluidized bed device in which the level of the fuel gas outlet of the fuel gas distribution tube is lower than the level of the air outlet of the air distribution tube.

[For production]

In the fluidized bed apparatus of claim (1), the air dispersion section is located at the bottom of the furnace, and the fluidization chamber can be formed from the bottom. Mechanism is no longer needed.

Furthermore, the air pipe itself stretches against the high temperature of the flow chamber, thereby eliminating the need for a mechanism for escaping the stretch. This simplifies the configuration of the gas dispersion section. Furthermore, the fluidized bed apparatus itself is of a low height and is compactly constructed.

In the fluidized bed apparatus of claim (2), in addition to the above-mentioned effects, the fluidizing/combustion air and the gas fuel are supplied from different parts and from multiple points, so that there is sufficient gas fuel in the fluidized bed. This reduces the phenomenon of gas fuel short-circuiting from a specific part to the freeboard part, and the gas fuel and the fluidizing/combustion air are well mixed, increasing the combustion rate.

In the fluidized bed apparatus of claim (3), since the gaseous fuel is injected into the fluidized medium from a position below the fluidizing and combustion air, the gaseous fuel is spread more thoroughly in the fluidized bed than above and combustion is facilitated. rate is improved. At the start of operation, a fluidized bed (
When preheating a fluidized medium (fluidized medium), when only high-temperature air is sent into the fluidization chamber from the air outlet through the air dispersion tube without sending gas fuel, this high-temperature air is sent to the gas fuel outlet of the gas fuel dispersion tube. Since the air is ejected from the air outlet of the air dispersion tube located at a higher level than The gas fuel jet port is not blocked by the fluidized medium particles fluidized by the ejected high-temperature gas, and the gas fuel is smoothly supplied after preheating and the device is started smoothly. In addition,
During preheating, the fluidized medium is fluidized in the area above the air outlet of the air dispersion tube, but the fluidized medium in the area below this, around the gas fuel outlet, is not fluidized and remains stationary. It is the floor.

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings.

1 and 2 show the overall configuration of a fluidized bed reforming furnace as a fluidized bed apparatus of the present invention, FIG. 1 is a longitudinal sectional front view, and FIG. 2 is a line from ■ to ■ in FIG. 1. It is an arrow sectional view.

In both figures, 10 is a furnace body, and a gas dispersion section 20 is installed on the bottom 10a of the furnace body 10 in the fluidization chamber 70, and the gas dispersion section 20 and a predetermined section are installed in the fluidization chamber 70 above it. A plurality of catalyst tubes 80 (in this embodiment, four stages above and below) serving as heat transfer tubes are disposed vertically apart from each other at a distance, crossing the flow chamber 70 . The gas dispersion section 20 and a position above it at a predetermined height are filled with a fluidizing medium when not in operation. A combustion exhaust gas extraction pipe 90 is attached to the freeboard 70a above the flow chamber 70. 90a is an exhaust gas discharge pipe.

The gas dispersion section 20 is constructed as shown in detail in FIGS. 3 and 4. 3 is a plan view of the gas dispersion section 20 taken along the line 2 in FIG. 1, and FIG. 4 is a sectional view taken along the line 2 of FIG.

A plurality of (four in this embodiment) large diameter air pipes 30 are branched from the ladder 31 to supply air within the flow chamber 70.
are mounted on the furnace bottom 10a and arranged at equal intervals, and each air pipe 30 has one end on the air supply ladder 31 side fixed to the furnace body 10, and the other end is a free end. It is said that Note that this free end side is closed. A large number of air dispersion tubes 40 are attached to each air tube 30 at regular intervals in the axial direction thereof and projecting upward. On the other hand, on the upper side of each air pipe 30, one end side is branched from a gas fuel supply header 51, and a plurality of gas fuel pipes 50 (four in this embodiment) having a smaller diameter than the air pipe 30 are provided.
is a spacer 4 spaced above the air distribution pipe 40.
5 and is installed in a state where it is placed on the Each gas fuel pipe 50 is also fixed to the furnace body 10 on the header 51 side, and the other end is a free end. A plurality of gas fuel dispersion pipes 60 are attached to each gas fuel pipe 50 and are respectively positioned between the adjacent air dispersion pipes 40 and protruding downward.

Here, the structures of the air distribution tube 40 and the gas fuel distribution tube 60 will be explained based on FIGS. 5 to 8.

In addition, FIG. 5 is a partially enlarged view of FIG. 4, FIG. 6 is a plan view taken along the line ■ in FIG. 5, FIG. 7 is a sectional view taken along the It is a sectional view taken along the line ■ in the figure.

The air dispersion pipe 40 includes an inner pipe 41 which is a short pipe that is branched from the air pipe 30 and is attached so as to protrude upward;
An annular chamber 48 and an inner tube 4 are closed by an outer tube 42 made of a short tube attached to a disk-shaped upper cover plate 43 and an annular lower cover plate 44 attached to the upper end of the annular chamber 48.
1, an air outlet 46 to an annular chamber 48 provided at the upper end portion, and an air outlet 47 provided in the outer tube 42 at a position lower than the air outlet 46. In this embodiment, as shown in FIG.
They are provided at four locations on the outer tube 42 at equal intervals in the circumferential direction and are out of phase with each other. A spacer 4 for mounting a gas fuel pipe 50 on the upper cover plate 43 of the air dispersion pipe 40 is placed at an appropriate position.
5 is installed.

On the other hand, the gas fuel distribution pipe 60 has a small hole 63 in the gas fuel pipe 50.
It consists of a small diameter pipe 61 attached via a cover plate 62 at the lower end thereof, and gas fuel jet ports 62 provided at two locations on the circumference of the lower end portion of the small diameter pipe 61.

The gas fuel outlet 62 is located below the air outlet 42 by a distance H.

The operation of the fluidized bed reforming furnace configured in this way will be explained.

At the start of operation, the fluidizing medium is filled at the bottom of the fluidizing chamber 70 with its upper surface positioned between the gas fuel pipe 50 and the catalyst pipe 80, and is in a stationary state. When high-temperature air of, for example, 900°C is supplied to the air header 31, this high-temperature air flows from the air header 31 into each of the air pipes 30 branched into a plurality of air pipes, and further into the air pipes 30 attached to the air pipes 30. Flows into the dispersion tube 40 and its inner tube 41
Air flows into the annular chamber 48 from an air outlet 46 at the upper end of the air outlet 48 . Then, while descending within the annular chamber 48, the air is divided into left and right sides to prevent drifting and flow from the air outlet 47 of the outer tube 42 to the flow chamber 70.
The fluidized medium is discharged into the fluidized bed and fluidized to form a fluidized bed and preheat the fluidized bed by heating the fluidized medium particles. The preheating effect is such that the fluidized bed temperature is e.g.
The process continues until the temperature reaches 00'C. During this preheating action, the fluidized medium above the level at which the air outlet 47 of the air distribution tube 40 is located is fluidized, and the fluidized medium around the gas fuel outlet 62 of the gas fuel distribution tube 60 located at a lower level is fluidized. Since the fluidizing medium is stationary, particles are prevented from entering the gas fuel outlet 62 and clogging it due to the influence of the flowing particles. When such a preheating action is completed, gas fuel such as city gas is supplied to the gas fuel ladder 51, gas fuel flows into each of the gas fuel pipes 50 branched from the gas fuel ladder 51, and further The gas flows into a large number of gas fuel distribution pipes 60, and is supplied from the gas fuel jet ports 62 into the fluidizing medium around the gas fuel jet ports 62. Then, the gas fuel is combusted in the fluidized bed which has been preheated as described above and is in a high temperature state, whereby the temperature of the fluidized bed is further increased and maintained at a predetermined temperature, for example, 800 to 900°C.

Therefore, in the combustion of this gas fuel in a fluidized bed, the fluidization/combustion air and the gas fuel come from different parts, and
Since the gas fuel is supplied from multiple points, the gas fuel is sufficiently dispersed and distributed throughout the fluidized bed, reducing the phenomenon that the gas fuel flows from a specific part to the freeboard part, and the gas fuel and the air for fluidization and combustion are well distributed. are mixed, increasing the combustion rate. In addition, at this time, the gas fuel is injected into the fluidized medium from a position below the fluidizing and combustion air, so the gas fuel is evenly distributed throughout the fluidized bed, further improving the combustion rate and increasing the fluidization rate. The floor will be heated evenly.

The fluidized bed thus formed expands and has a higher bed height, and as a result of this contacting the catalyst tubes 80 or the catalyst tubes 80 being buried in the fluidized bed, the catalyst tubes 80 are heated evenly. from the lower supply pipe 81 to the catalyst pipe 8
Hydrocarbon fuel, such as city gas, and steam supplied into the 0 are uniformly heated by the action of the catalyst and converted into hydrogen gas and carbon monoxide gas, which are then passed through the upper discharge pipe 8 of the upper stage catalyst pipe 80.
Hydrogen gas is taken out from 2 and used for fuel cells, etc.

The combustion exhaust gas ascends the freeboard 70a, is sucked into the exhaust gas take-off pipe 90, and is taken out from the exhaust gas exhaust pipe 90a.

〔Effect of the invention〕

As detailed above, in the present invention, by adopting the configuration as claimed in claim (1), there is no need to consider thermal expansion due to high temperatures, and the configuration of the gas dispersion section can be simplified. By arranging the gas dispersion section at the bottom of the furnace, the height of the fluidized bed apparatus itself can be reduced and it can be formed compactly. Moreover, by adopting the configuration as claimed in claim (2), in addition to the above-mentioned effects, the probability of gas fuel escaping from a specific part of the fluidized bed to the freeboard part through a short bus is reduced, and the gas fuel and fluidization are reduced. The gas fuel is efficiently mixed with the combustion air and the fluidized bed can be heated evenly.Furthermore, with the configuration as claimed in claim (3), the gas fuel Since the gas fuel is injected into the fluidized medium from a position below the fluidizing and combustion air, the gaseous fuel is even more thoroughly distributed in the fluidized bed than above, improving the combustion rate.At the start of operation, the fluidized bed is When preheating, high-temperature air is fluidized by the high-temperature gas ejected from the air outlet of the air distribution tube, when only high-temperature air is sent from the air tube through the air distribution tube into the fluidization chamber from the air outlet of the air distribution tube. The gas fuel injection port is not blocked by the fluidized fluid particles, and the gas fuel can be smoothly supplied after preheating, and the apparatus can be started smoothly.

[Brief explanation of drawings]

Each of the drawings shows an embodiment of the present invention, and FIGS. 1 and 2 show the overall configuration of a fluidized bed reforming furnace as a fluidized bed apparatus of the present invention, and FIG. 1 is a longitudinal sectional front view. , FIG. 2 is a sectional view taken along the line ■ to ■ in FIG. 1, FIG. 3 is a plan view taken along the line ■ in FIG. ■A sectional view taken along the line, Figure 5 is a partially enlarged view of Figure 4,
Figure 6 is a plan view taken from the ■ arrow in Figure 5, and Figure 7 is the ■ line in Figure 5.
FIG. 8 is a sectional view taken along the line ■ in FIG. 5. DESCRIPTION OF SYMBOLS 10...Furnace body, ・Gas distribution part, 30 Gas distribution tube, 47... Fuel pipe, 60... ・Gas fuel jet port, ・Catalyst tube, 90...

Claims (3)

[Claims] (1) At the bottom of the furnace, a plurality of air pipes with one end fixed to the furnace and the other end free are arranged side by side at approximately equal intervals, and the air pipes are arranged at approximately equal intervals in the axial direction of each air pipe. A fluidized bed apparatus characterized by having a large number of air dispersion pipes protruding upward from the top. (2) At the bottom of the furnace, a plurality of air pipes with one end fixed to the furnace and the other end free are arranged side by side at approximately equal intervals, and the air pipes are arranged at approximately equal intervals in the axial direction of each air pipe. A large number of air dispersion pipes are provided that protrude upward from the air pipe, and a plurality of gas fuel pipes are installed at approximately equal intervals above the air pipe, approximately parallel to the air pipe, with one end fixed to the furnace and the other end free. A fluidized bed apparatus characterized in that a plurality of gas fuel dispersion pipes are provided in parallel with each other, and are respectively positioned between the air dispersion pipes and protrude downward from the gas fuel pipes. (3) The fluidized bed apparatus according to claim (2), wherein the level of the fuel gas outlet of the fuel gas distribution tube is lower than the level of the air outlet of the air distribution tube.