JPS58214701A - Fluidized-bed heat exchanger to which baffle plate device is arranged - 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 The present invention relates to fluidized beds, and more particularly to a fluidized bed heat exchanger provided with a baffle arrangement for separating entrained particulate bed material from exhaust air and gaseous combustion products. Regarding.

The use of fluidized beds has been recognized as an attractive means of heat generation. In this type of device, air is passed through a bed of particulate matter consisting of a mixture of inert materials and fossil fuels such as coal to fluidize the bed and facilitate combustion of the fuel. The use of fluidized bed equipment as steam generators, boilers, vaporizers, etc. has an attractive combined effect of high heat release, improved heat transfer to surfaces within the bed, and miniaturization of the equipment. can get.

In a fluidized bed reaction process, unreacted or partially reacted particles are always entrained in the air and combustion products flowing upward from the bed escape into the area immediately above the bed, commonly referred to as the "freeboard space."

To reduce heat loss and maintain high inlet temperatures, devices of this type often must be designed to limit the height of the freeboard space to less than an optimum value.

However, limiting the height of the freeboard space as described above has disadvantages. For example, the residence time of the gas in the freeboard space is short, resulting in less than optimal combustion efficiency. Additionally, the height of the freeboard space is limited by maintaining the temperature of the freeboard space at the operating temperature of the floor, at a temperature above the operating temperature, or at a temperature near the operating temperature. This contradicts the design goal of promoting a more complete reaction. Furthermore, there is a poor distribution of the gaseous combustion products and the combustion products become too rich in carbon monoxide and hydrocarbons, resulting in incomplete combustion.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a fluidized bed heat exchanger which has a relatively low freeboard space height and which eliminates the above-mentioned disadvantages.

Another object of the present invention is to provide a fluidized bed heat exchanger configured to increase the residence time of bed particles in the freeboard space when compared to a similar bed of the same size.

Yet another object of the present invention is to provide a fluidized bed heat exchanger configured to increase the turbulence of air and gaseous combustion products to improve reaction efficiency and better gas-solid contact. Chill by offering.

Another object of the invention is a baffle device disposed inside a freeboard book space above a fluidized bed, comprising:
To provide a baffle plate device configured to collide air with gaseous combustion products to remove the accompanying particulate matter and cause it to fall to the floor by gravity.

Yet another object of the present invention is to inject the heat-absorbing medium downward toward the floor from a location close to the baffle plate, thereby promoting a more complete reaction and controlling the entire floor surface. It is an object of the present invention to provide a fluidized bed heat exchanger configured to perform the following steps.

Still another object of the present invention is to provide a fluidized bed heating system configured to complete the combustion process by injecting a sufficient amount of additional air downwardly toward the bed from proximate the baffle arrangement as described above. The purpose is to provide an exchanger.

Mt-9 It is an object of the present invention to provide a fluidized bed heat exchanger provided with means for flowing air and combustion products in the freeboard area towards the baffle arrangement described above.

To achieve the above-mentioned and other objects, a heat exchanger according to the invention includes a grate supported within a housing and receiving a bed consisting at least in part of combustible particulate matter. Air flows through the grid and the bed of particulate matter, fluidizing the particulate matter and promoting combustion of the combustible material. The baffle device is located above the floor and collides with the particulate matter that accompanies the air and gaseous combustion products to remove the particulate matter from the air and gaseous combustion products and allow it to fall by gravity to the floor. Return to A series of tube sections are provided within the housing to direct air and gaseous combustion products toward the baffle device and to inject a heat absorbing medium proximate the baffle device downwardly toward the floor. Ru.

The above brief description of the invention, as well as further objects, features and advantages of the invention, will be understood with reference to the accompanying drawings:
BRIEF DESCRIPTION OF THE DRAWINGS The following detailed description of the presently preferred but non-illustrative embodiments of the invention is believed to be more fully understood.

In FIG. 1 of the drawings, which shows a fluidized bed steam generator having features of the invention, the reference numeral 10 designates the entire enclosure consisting of a front wall 12, a rear wall 14 and two side walls designated 16. shows. The upper part of the enclosure 10, which has been omitted for illustration purposes, comprises a convection area, a roof section, and an outlet for discharging the mixture of air and combustion gases from the enclosure 10 in a conventional manner.

A particulate matter bed, indicated generally by the reference numeral 18, is located within the enclosure 10 (
In the case of this embodiment, the grid 2 is disposed inside the boiler 10) and has holes extending horizontally in the lower part of the enclosure 10.
It's on top of 0. Bed 18 may consist of discrete particles of inert material and fuel material, such as bituminous coal. Immediately below the grate 20 is an air-filled chamber 22, and an air-filled chamber 24 is provided through the rear wall 14 of the boiler to communicate with the chamber 22 and to draw air from an external air source (not shown) to the chamber 2.
Air is distributed between 2. It will be appreciated that, in accordance with conventional practice, the distribution of air to the chamber 22 may be controlled by a control device (not shown) such as a wind door.

An unignited burner 26 passes through the wall 12 at the front and connects to the grate 2.
0 and performs the initial ignition of the bed 18 at the start of combustion.

For ease of understanding, multiple feeders are placed on the wall 12°14
Alternatively, one or more of the fuel cells 16 may be provided to introduce particulate fuel material, such as coal, into the area above the bed 18 of the enclosure 10 to continuously supply the bed 18 with fuel material. A drainage device may also be provided to remove spent particulate matter from the bed. Since these constituent members are not constituent elements of the present invention, they are not shown in the drawings and will not be described in detail.

As shown most clearly in FIGS. 1 and 2, the can walls 12, 14, and 16 are formed by a plurality of vertically extending spaced apart tubes 28, with a diametrical diameter along the entire length of each tube. It has continuous fins 30 extending from opposite locations. The fins 30 of adjacent tubes 2B are articulated together to make the resulting wall structure airtight. Although not shown in the drawings, suitable headers, downcomers, etc. may be provided to introduce water from an external source into the lower portions of walls 12, 14 and 16, allowing water to flow upwardly through the walls and away from the fluidized bed. The supplied heat can convert water into steam.

Additionally, the enclosure 10 is used to provide additional heat to the water from the fluidized bed.
A group of tube rows 12 are provided above the floor 18, one of these tube rows being shown in FIG. Each tube extends windingly from an inlet header 34 located on the exterior of the housing adjacent rear wall 14 to an outlet header (not shown) also located on the exterior of housing 10. The remaining tubes 32 in the tube row are shown perpendicular to the drawing.
extends parallel to. These tubes 32 are provided to provide additional heat to the water flowing through the tubes for superheating, reheating, etc. purposes.

A plurality of spaced parallel chevrons 36 extend horizontally within the enclosure 10 immediately above the floor 18. This chevron-shaped piece 36 extends across the width of the nozzle in the middle of the side wall 16 and is supported at its ends relative to the side wall 16 by ears, support beams, surround wall recesses, etc. in the conventional manner. has been done. The chevron piece 36 is arranged with its apex facing upward,
A distribution pipe 38 is inserted into the interior of each chevron 36 and extends the entire length of the chevron. Second
As shown in the figure, a plurality of pipes 38 are arranged in a spaced apart parallel relationship between two headers 40 and 42 (see FIG. 2).
and distributes heat absorbing medium from an external source to the pipe 3B. As shown in FIG. 1, a plurality of holes or discharge openings are formed in the lower portion of the pipe 38.
The heat absorbing medium is discharged outwardly and downwardly towards the floor 18 . Examples of heat-absorbing media injected from the distributor 38 can include air, liquids, flue gases or reflux dust or reflux substances, as well as receptors such as fresh limestone. In this way, detectable heat inside the freeboard space can be absorbed and at the same time CO2 can be removed by the receptor from the carbon content present in the mixture of air and gaseous combustion products, Moreover, it is possible to avoid overloading the capacity of the outlet combined with the enclosure 10. Also, when air is used as the heat absorbing medium, sufficient air can be injected to completely burn out the particulate fuel material in the bed.

A plurality of vertical pipes, only one of which is shown with reference numeral 44 in FIG. Furthermore, it is also possible to add a heat absorbing medium and release it.

The pipe 46 is disposed directly below the chevron 36 and above the upper surface of the floor 18. The pipe 46 has a bent shape,
As a result, a plurality of spaced apart section sides 46a are formed.

As shown in FIG.
The cooling fluid source may extend externally from the shaft and be connected to a cooling fluid source, which source may be the same as the cooling fluid source that supplies water to tubes 28 and 32 forming walls 12, 14, and 16. There may be. As can be seen from FIGS. 1 and 3, the division side 46a is arranged in a staggered and eccentric relationship with respect to the chevron piece 36 and the distribution pipe 38, and because of such a relationship, details will not be given. For the reasons explained later, the floor 18
The air and gases from the tube are directed to the angle piece and distribution pipe.

In operation, air is introduced into chamber 22 through inlet 24 and flows upwardly through grate 20 into the bed to loosen particulate matter in bed 18 and fluidize the bed. The ignition burner 26 ignites the particulate fuel material until the bed 18 is heated to a predetermined temperature to maintain combustion of the particulate fuel material, after which the ignition burner is turned off and the particulate fuel material is ignited in an amount necessary to maintain the predetermined bed temperature. of new particulate fuel material.

As shown in FIG. 3, the mixture of air and gaseous combustion products flowing upwardly from the bed 18 is reduced due to the staggered relationship of the tube side 46a to the chevron 36.
It flows in a bead-like shape. The mixture on the side 46a flows towards the ridge 36 and the distribution pipe 38, so that the mixture stream hits the ridge and the distribution pipe and the particulate matter entrained in the mixture is separated. , the particulate matter falls back to the floor due to gravity. This, of course, lengthens the reaction time of the accompanying particles, but in addition, the turbulence within the freeboard is intense, which promotes a more complete reaction and creates a non-uniform reaction. The combustion gases and air are forced to mix, resulting in a homogeneous product.

The distribution pipe 38 distributes the heat absorbing medium from the manifolds 4o and 42 towards the floor 18 so that:
A more complete reaction is promoted and the bed temperature is controlled. That is, peak temperatures are reduced or limited, and areas of intense fireballing are reduced.

The heat absorbing medium from the distribution pipes 3-8 also serves to push the entrained particulate matter downwards and back into the bed.

Pipe 44 is used to inject additional heat absorbing media into the freeboard area or directly onto the floor to provide cooling and remove any fine particles that may be entrained in the air and gas mixture flowing upward in the freeboard area. Can blow away dust.

What should be noted here is the angle piece 36 and the distribution pipe 38.
and section side 46a act as a heat dissipation screen above the bed to retain sufficient reaction heat to make the reaction more complete in the freeboard area.

Cooling fluid, supplied from the same source as the fluid passing through walls 12.14 and 16, is introduced into tube 46 and flows through section side 46a to keep the section side cool and reduce the temperature of the freeboard area. It can also be used as an auxiliary means for control. - As a result of the above-mentioned arrangement, it is possible to limit the height of the freeboard to reduce heat losses and keep the input temperature to the gas turbine generator high, while eliminating the above-mentioned disadvantages.

Another embodiment of a fluidized bed heat exchanger according to the invention is shown in FIG. 4, in which identical parts have been given the same reference numerals. In the embodiment of FIG. 4, the rear wall 14 is higher than the front wall 12 and has a gas exhaust opening 50 formed in the upper part of the rear wall. As shown, the enclosure 10 is provided with a roof 52 that slopes upwardly from the front wall 12 to the rear wall 14. With this arrangement, the mixture of air and gaseous combustion products flows upwardly and to the right, as indicated by the arrows in FIG. chevron piece 36, gas distributor 38 (therefore header 4
0 and 42) and the pipe 46 are arranged adjacent to the discharge port 5o at the upper right corner of the housing, and are arranged in a plane inclined at a certain angle with respect to the horizontal direction. As a result of this arrangement, air and gases flowing upwardly from the floor 18 pass over each member in a manner similar to that of the previously described embodiments.

Accordingly, the embodiment of FIG. 4 provides the same benefits and features disclosed in the embodiment of FIGS. 1-3.

In the foregoing description, for illustrative purposes, both embodiments of the invention have been described in connection with a steam generator; however, within the scope of the technical idea of the invention, embodiments of the invention may We believe that it is readily apparent that other types of fluidized bed heat exchangers can be used.

Many modifications, changes, and substitutions are possible within the scope of the above-mentioned disclosure, and in some cases, applications may be considered that make use of the remaining features without adopting some of the features of the present invention. Therefore, the claims should be interpreted broadly and should be interpreted and interpreted in accordance with the technical spirit and scope of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a portion of a fluidized bed heat exchanger according to the invention. FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. FIG. 3 is an enlarged cross-sectional view of a portion of the configuration of FIG. FIG. 4 is a partial vertical sectional view showing another embodiment of the present invention. 10... Enclosing body (boiler, housing) 18...
Floor 2o... Lattice 36... Chevron piece
38...Distribution pipe 46...Pipe
46a...Precinct side! Applicant for patent Foster Wheeler Energy drawings, I; 'Changes to content L5 Selected 11 Figure 3 Figure 2 Procedural amendment (method) October 14, 1980 Commissioner of the Patent Office Kazuo Wakasugi 1 , Indication of the case 1982 Patent No. 1 No. 97891 2, Title of the invention Fluidized bed heat exchanger with a baffle plate device 3 Relationship with the case of the person making the amendment Patent applicant address Name (Name) Foster Wheeler Energy Corporation 4, Agent

Claims (1)

[Claims] a housing, a grate member supported within the housing for receiving a bed of combustible particulate matter; air introduction means for fluidizing the bed to promote combustion of said combustible material; an outlet located in the upper part of said housing for discharging said air and gaseous combustion products from said housing; and particulate matter. disposed in the housing at an intermediate portion between the floor consisting of the air and the outlet, the air colliding with the particulate matter accompanying the gaseous combustion products to cause the particulate matter to fall under the force of gravity; a baffle device that returns to the floor; a member within the housing that directs the air and gaseous combustion products toward the baffle device; and a member that directs the air and gaseous combustion products toward the floor from a point adjacent to the baffle device; and 'means for injecting a heat absorbing medium.