JPS618502A - Combustion chamber structure of multitubular once-through boiler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in the combustion chamber structure of a multi-tubular once-through boiler using low quality oil fuel.

[Technical background of the invention and its problems] Conventional steam generators include vertical boilers, furnace tube boilers, once-through boilers, and the like. Among recent small boilers, multi-tube once-through boilers, which require a small installation space, are rapidly becoming popular due to improvements in thermal efficiency and reliability. This is because in small multi-tube once-through boilers, it is easy to freely adapt the combustion chamber according to the capacity by changing the arrangement of the water tubes.
When burning high-quality oil such as oil, combustibility due to the structure of the combustion chamber is rarely a problem.

However, when burning low-quality oil fuels such as B heavy oil and CM oil, combustibility has not yet been sufficiently improved, such as soot generation due to incomplete combustion or carbonization through dry distillation of unburned adhering parts.

[Object of the Invention] The present invention has been made in view of the above points, and its object is to provide a combustion chamber structure for a multi-tubular once-through boiler that improves the combustibility of low-quality oil fuel. be.

[Summary of the Invention] In order to achieve the above object, the present invention connects the F section header and the lower header with a large number of water pipes, arranges these water pipes in close contact with each other in an annular shape, and In a multi-tubular once-through boiler where the space is formed into a combustion chamber, the combustion device is installed almost in the center of the upper header, a gas flow path is formed at the bottom of each water tube, and a refractory material with breathability is installed. To provide a combustion chamber structure for a multi-tubular once-through boiler, characterized in that its cross section is bridge-shaped connecting a water pipe and a bottom surface, and is formed to surround a gas flow path on the combustion chamber side.

Embodiments of the present invention shown in the drawings will be described below. Fig. 1 is a schematic vertical cross-sectional view showing an embodiment of the present invention (a single-row can body of a throttle water pipe), and Figs. 2 and 3 are lines ■-■ and ■-■ in Fig. 1, respectively. FIG. The reference numeral (1) in the drawings is an annular upper header, and (2) is also an annular lower header. These upper and lower headers are in close contact with each other to form an annular shape, and the combustion chamber (4) is located inside the header.
They are connected by a large number of water pipes (3). Almost in the center of the upper header is a combustion device (
5) is provided.

Both ends of each of the water tubes, which are in close contact with each other, are formed into reduced diameter portions (6) to facilitate welding to the upper and lower headers. The gap between the lit diameter parts on the upper header side is closed with airtight fireproof material (1'iJ), and the reduced diameter part (6) on the lower header side has a gap between the reduced diameter parts. It has the required length to be suitable for the flow path of combustion gas, and the gap forms a gas flow path (7) between the reduced diameter portions leading from the combustion chamber to the outside of the annular water pipe. The center of the lower header, which forms a combustion chamber, is closed with airtight fireproof material to make the space surrounded by water pipes a combustion chamber, and the combustion chamber on the lower header side extends to the bottom (9). has been done.

The cross section of the gas flow path (7) between the reduced diameter parts on the combustion chamber side is the same as that of each water pipe (3).
) and the bottom surface (9) of the combustion chamber are surrounded by a fireproof material (8) in the form of a bridge, and this fireproof material has a number of passages leading from the combustion chamber to the gas flow path between the reduced diameter parts. It has pores. A can body cover (2) is provided on the outside of the annularly arranged water tubes with a required gap, and a water tube outside gas flow path Q4) is formed between the water tubes and the can body cover. A flue a9 leading from the gas flow path outside the water tube to the outside of the system is provided in a part of the can cover.

FIG. 4 is a schematic vertical cross section showing another embodiment of the present invention (a single-row can body with finned water pipes), and FIGS.
FIG. 3 is a cross-sectional view taken along lines v-V and Vl''-VI in the figure.

The water pipes (3) are connected at the fins (2) leaving a water pipe gap of a required length on the lower header side.

The water pipe gap that eliminates the connection by fins communicates the combustion chamber (4) with the water pipe outer gas flow path 04).
is formed. The other parts are the same as those in FIGS. 1, 2, and 3, so the explanation will be omitted.

FIG. 7 is a schematic vertical cross-sectional view showing still another embodiment of the present invention (two rows of squeezing water pipes), and FIG.

Figures 9 and 10 are the ■-■ lines in Figure 7, respectively.

It is a sectional view taken along the IX-IX line and the XX line.

The reference numerals in the drawings indicate the first row of water pipes, and these main pipes are closely connected to each other in an annular shape, connecting the upper and lower headers, and forming the combustion chamber inside.

Furthermore, both ends of this main pipe are formed with reduced diameter parts (6), and the reduced diameter part on the upper header side is closed with an airtight fireproof material.
A gas flow path (7) between the reduced diameter portions of the first row of water pipes is connected between the reduced diameter portions on the lower header side, which communicates the combustion chamber with the outside of the first row of water pipes.
0 A second row main pipe (1 negative) is provided outside the first row water pipe, which is concentric with the first row water pipe with a required gap, and an inter-water pipe gas flow is provided between the first row water pipe and the second row water pipe. A channel (11) is formed.The second row of water pipes are also in close contact with each other and connect the upper and lower headers.Furthermore, both ends of this water pipe are also formed in a reduced diameter section, and the lower header side has a reduced diameter section. The space between the diameter parts is closed with an airtight fireproof material, and the space between the reduced diameter parts on the upper header side is connected to the water pipe gas flow path and the second
A gas flow path (7) between the reduced diameter portions of the second row water pipes is connected to the outside of the row water pipes. A can body cover ■ is provided on the outside of the second row water pipe with a required gap from the second row water pipe, and a second row water pipe outer gas flow path [phase] is provided between the second row water pipe and the can body cover. is formed. In addition, a part of the can body cover is provided with a flue opening that communicates with the outside of the system from the second row water pipe outer gas flow path (B).The cross section of the gas flow path from the combustion chamber to the flue is It will be formed into a hairpin shape.

On the surface of the water pipes facing the gas flow path between the water pipes and the outer gas flow path of the second row of water pipes, a number of studs (calendar marks) for promoting heat transfer are nailed at arbitrary pitches. Since it is the same as that in FIG. 3, the explanation will be omitted.

Next, regarding the operation, first, let's look at the one-row can body with throttle water pipes shown in FIGS. 1, 2, and 3, as well as FIGS. 4 and 5.

The single-row can body with finned main pipes shown in FIG. 6 will be explained.

When the combustion device (5) operates, combustion occurs in the combustion chamber (4). The combustion gas in the combustion chamber heats the water pipe and the refractory material with IC and air permeability mainly by radiation and heat transfer. The combustion gas further superheats the breathable refractory material (8) by convection heat transfer, and then lowers the temperature and passes through the gas flow path (7) between the reduced diameter parts.
) (or the inter-water tube gas flow path (it)) to reach the water tube outer gas flow path 04). The combustion gas heats the water pipe mainly by convection heat transfer in the gas flow path outside the water pipe, lowers its temperature, and is discharged from the flue to the outside of the system. At this time, unburned soot or residual carbon in the combustion chamber is carried by the combustion gas and reaches the red-hot breathable refractory material, and complete combustion is performed by the heat of the refractory material.

Next, the two-row can bodies shown in FIGS. 7, 8, 9, and 10 will be explained. The combustion gas that has passed from the combustion chamber (4) through the breathable refractory material (8) and between the reduced diameter portions of the first row of water pipes (7) flows through the inter-water pipe gas flow path (2) and the second row of water pipes. It passes through the gas flow path between the reduced diameter parts (the sword/second row water tube outer gas flow path [F], passes through the flue ■, and is discharged to the outside of the system.

Convection heat transfer is mainly performed in the gas flow path between the main pipes and the gas flow path outside the second row of water tubes, and the effect is doubled by the action of the studs (2) as heat transfer promoters. The rest is the same as the one-row can body of the throttle water pipe, etc., so the explanation will be omitted. Although the above-mentioned two-row can body has been described as a two-row can body with throttle water pipes, the same effect can be obtained by using a structure in which fins are provided between the water pipes to connect them, as in FIG. or,
1-row can body with squeeze water pipe or 1 with finned water pipe
Similarly to the two-row can body, the effect of convective heat transfer can be further improved by arranging a large number of studs at arbitrary pitches on the surface of the water tube facing the gas flow path outside the water tube.

[Effects of the Invention] The present invention is configured as described above, and the unburned components in the combustion chamber are carried by the combustion gas and reach the red-hot breathable refractory material, thereby completely oxidizing and burning. Therefore, even if low-quality oil is used as fuel, complete combustion can be achieved and combustibility can be improved.In addition, the fire resistance system with a large amount of heat retention through ventilation allows the downstream side to It is possible to prevent unburned components such as soot from adhering to the heat transfer surface of the heat transfer surface, and the heat transfer efficiency in the low temperature region is also improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal section showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a IV in FIG.
-TV sectional view, FIG. 4 is a vertical sectional view showing another embodiment, FIG. 5 is a v-v sectional view of FIG. 4, and FIG. 6 is a Vl-vi sectional view of FIG. 4. , FIG. 7 is a schematic vertical cross-sectional view showing still another embodiment, FIG. 8 is a cross-sectional view taken along the line ■-■ in FIG. 7, FIG. 9 is a cross-sectional view taken along the Iχ-IX line in FIG. 7, and FIG. 7 is a sectional view taken along the line X--X in FIG. 7. (1) Upper header (2) Lower header (
3) Water pipe (4) Combustion chamber (5) Combustion device
(6) Reduced diameter part (7) Gas passage between reduced diameter parts (
8) Fireproof material (9) Bottom (to) Fin (1
1) Gas flow path between water pipes Refractory material ■ Can body cover
04) Water pipe outside gas flow path west Flue West 1st row water pipe surface 2nd row water pipe [Phase] Gas flow path between water pipes [F] 2nd row water pipe outside gas flow path ■ Stud ゛1st Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 9 2ti Figure 8 Figure 9 Figure 1O Figure

Claims (3)

[Claims] (1) The upper header (1) and the lower header (2) are connected by a large number of water pipes (3), and these water pipes (3) are arranged in close proximity to each other in a ring shape, and the inner space is used for combustion. In a multi-tubular once-through boiler formed in chamber (4), upper header (1)
A combustion device (5) is provided almost at the center of the pipe, gas channels (7) and (11) are formed at the bottom of each water pipe (1), and a refractory material (8) with breathability is installed in the bottom of the pipe. The cross section is the water pipe and the bottom (
9) and the combustion chamber (4).
A combustion chamber structure of a multi-tubular once-through boiler characterized by being formed so as to surround a side gas flow passage. (2) The lower part of each water pipe is formed into a reduced diameter part (6) of a required length to form an inter-reduced diameter gas flow path (7) between the reduced diameter parts of the water pipes. Combustion chamber structure of the multi-tubular once-through boiler according to scope 1. (3) A patent characterized in that the plurality of water pipes are connected by a fin (10) leaving a water pipe gap of a required length on the lower header side, and the gap is used as a water pipe gap gas flow path (11). A combustion chamber structure of a multi-tubular once-through boiler according to claim 1.