JPS5915709A - Steam generator with fluidized-bed combustion chamber - 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 has a fluidized bed combustion chamber, the gas flue exiting from it is limited to a cold wall and extends, and the cross section of the flue airflow is 60% of the surface area of the fluidized bed combustion chamber. The present invention relates to a steam generator with a 60% reduction.

This loincloth steam generator is manufactured by the applicant's 1' in-house company.
This falls under prior art. The degree of fines in the fuel removed from the fluidized bed depends on the nature of the fuel used in the fluidized bed combustion chamber, its particle size distribution, and the amount of air injected into the bed. Most of these fuel particles are located in the cyclone and/or cold zone of the flue gas.
It is common practice to separate in a filtration machine and to return the material thus separated to the fluidized bed. The probability that the returned particles will be taken out of the fluidized bed again is quite high. Therefore, the load on the filtration rock increases, and as a result, the filtration area must be made very large, or the pressure drop of the P:a machine increases, consuming considerable energy.

Due to the relatively high coal content of the residue, the residue is unsuitable for some applications, for example in the construction industry. If it cannot be used satisfactorily, it will cause a waste problem.

It is an object of the invention to obviate these disadvantages and to considerably reduce the proportion of fuel that finally leaves the plant together with ash and waste.

Therefore, according to the present invention, the liquid and/or
A reburner (afterburner) for gaseous fuel (combustion fuel) is placed in a flue air stream with a narrow cross section.The afterburner further burns the combustion fuel. A person skilled in the art must, at first impression, consider this solution to be unreasonable, since it is relatively expensive and additional storage volume is required for this fuel. It has been found that consuming only a small amount of combustion fuel reduces the loss of solid fuel from the fluidized bed to a negligible level, thus increasing the economics of the plant.

The heat insulation described in item (2) of the specific Wfdi requirement range due to the reduction of radiation ffM loss allows the reburning burner to function satisfactorily and reduces the amount of fuel consumed for combustion.

The uncooled radiation velocity shield according to claim (3) reduces radiation losses and therefore the consumption of combustion fuel.

According to claim (4), if a radiation ffM shield is devised and used as a flame shield.

If it is not decided to extinguish the flame of the reburn burner, the consumption of combustion fuel can be further reduced, since there is no critical level at which the fuel consumption must be reached.

Temperature control f111 according to claim (5)
Well then.

It ensures that the combustion temperature of the residual carbon present in the flue gas is maintained, regardless of the heat release value of the flue gas entering the reburning burner from the fluidized bed combustion chamber.

In combination with a device for supplying air to maintain combustion according to claim (6), by reliably supplying only the air required to maintain combustion to the afterburner burner, % To prevent unnecessary loss of waste gas during plant operation.

Adapting reburn burners to burn waste fuel helps save on expensive combustion fuel.

Embodiments of the invention will be explained in greater detail with reference to a schematic diagram of a vertical section through a steam generator.

The steam generator 1 includes a fluidized bed combustion chamber 2 whose surface area is rectangular. There is a vertical ascending flue 4 and a vertical descending flue 6 which are also narrow in this area. The combustion chamber 2 is delimited by a so-called diaphragm tube wall and has a bottom part 8. Front side 10 degrees, back side 12, other both sides 14.
and a side surface 16 extending obliquely from the back surface 12 to the ascending flue 4
It is made up of parallel tubes that are in bath contact with each other. The walls and the tops of the flues 4, 6 are also integrally formed as a diaphragm tube wall.

A superheater 22 consisting of several vertical tube panels is connected to a rising flue 4
However, the resuperheater 26 and the economizer 2 below it are
4 is placed in the descending flue 6. An air opening 28 is formed in the combustion chamber 20 holder 8.

Around the chamber 20 there is airtightly connected an air chamber 30 subdivided into three zones 36, 38, 40 by two vertical partitions 32 each with a flap 34.

The flap 34 allows the royal family to communicate with each other. A compressor 44 is connected to the central zone 36 by a tube 42.

The afterburning burners 50 (i.e., three on each side wall) are located near the bottom of the ascending flue so that their flames are uniformly emitted over the entire cross section.

In the vicinity of the six afterburners 50, the four walls of the flue 4 are lined with a plastic refractory 52 as insulation against the heat of the flames of the afterburners. The flue 4 has three radial fiber shells 5 upstream of the reburning burner 50 on the flue gas side.
6 are arranged, but these are also Kakewatahei-tai,
It extends across the entire width of the flue 40. Five more are arranged downstream of the reburning burner on the flue gas side, and non-cooled radiation shielding bodies 56 are also arranged in two staggered rows.
This also extends throughout flue 4 II@. Shielding body 54
．． 56 is made of a heat-resistant, thin metal sheet, and is curved in cross section for strength.

The operation of the steam generator is as follows.

In terms of operation, air is preheated by a device not shown in the figure and compressed using +S44 to create a central zone 3 of an air pocket of 3 degrees.
6 and open the flap 34.

Air spreads to dilute acid 38,40. The air rises through the opening 28 and enters the fluidized bed combustion chamber 2, which contains the ms bed 20, which also consists of particles of inert material and a small amount of coal and D). The coal burns in the fluidized bed 20 at about 800°C, and the heat generated and the bottom 8 and surrounding walls io, i2. An equilibrium exists between intense heat transfer to i4. The flue gas generated during combustion flows out of the moving bed 20, entraining extremely small particles of coal and ash shells, and is then transferred to an area where a re-combustion burner is arranged to receive fuel for combustion. In this region, the temperature is as high as 900 degrees Celsius, and the particles are heated by the radiation from the flame of the afterburner 50 to temperatures as high as the thighs, where they ignite and burn. occurs and therefore the amount of combustion fuel that needs to be supplied to the afterburner 50 in order to reach the average temperature of 70 J) just mentioned is equal to the total fuel consumption of the steam generator. Approximately 1
It is only a very small amount, ranging from % to a few threads. Shielding body 54.5
6 and the plastic refractory 52 significantly reduce heat transfer from the afterburn burner area, thus saving expensive combustion fuel for the afterburn burner.

Next, the flue gas, which has a temperature of about 900°C, flows through the tubes of the superheater 22, resuperheater 26, and economizer 24, and then passes through the ash husks '#II & device (not shown). (not shown) and chimney (not shown).

If, for example, waste fuel from a chemical factory can be utilized, one or more reburning burners can be modified and applied to burn such fuel, or even fourteen. A separate reburn burner can be installed that burns only the Such a circuit arrangement for controlling one type of burner is known from, for example, Swiss Patent Application No. 400,427.

As a controlled condition for controlling the sound of supplying combustion fuel to the reburning burner, for example, two temperature measuring elements such as thermocouples 62 arranged on two outermost radiant fiber shields 56 are used. The temperature signal produced as a signal summation can also be used. It may be advantageous not to use such a summed signal, but to use the smaller signal measured by the fixed thermocouple 62, in which case the signal is detected by a selector circuit.

Invention? 4t required to understand! Although the known details of b have been omitted from the explanation of the temporary steam generation system, they include a device for heating air to maintain combustion noise;

It includes devices for introducing fuel and lime into the fluidized bed, temporary storage for supplying fuel for combustion, temporary storage for supplying water, and temporary storage for removing steam.

[Brief explanation of the drawing]

The drawing is a schematic diagram of a vertical section of a temporary steam generating device according to the present invention. 1 is a steam generator, and 2 is a fluidized bed combustion chamber. 4 is the ascending flue, 6 is the descending flue, and 8 is the bottom. 10 is the front, 12 is the back, and 14 is the side. 16 is a sloped side portion, and 20 is a fluidized bed. 22 is a superheater, 24 is an energy saver, and 26 is a resuperheater. 28 is an opening, 30 is an air pocket, 32 is a vertical bulkhead, 34 is a flap, 36.38j40 is a zone of air pocket (36 is a central zone), 42 is a pipe, and 44 is a compressor. 50 is a reburning burner, 52 is a plastic refractory, 54.5
6 is a shield, and 62 is a thermocouple. Agent Asamura Akigai 4 people 1

Claims (6)

[Claims] (1) In order to burn the unburned fuel particles coming out of the fluidized bed combustion chamber, a small number of afterburners for liquid and/or gaseous fuel (combustion fuel) are installed in the cross section. It is characterized by its placement in the narrow flue airflow.There is a fluidized bed combustion chamber.The gas flue exiting from this is limited by the cold wall and extends, and the cross section of the flue airflow is in the fluidized bed combustion chamber. 60% of the surface area of the steam generator. (2) The cooling flue wall is insulated from the reburning burner (in close proximity), preferably with a molded plastic refractory. Steam generation according to item (1) above. Device. (3) At least one uncooled radiant fiber shell is arranged downstream and/or upstream of the reburn burner in the flue. The steam generator according to item (1) or item (2) above. (4) Radiation characterized by the radial fiber body being a spanning body? a At least one shield is upstream of the reburn burner. The steam generator according to item (3) above. (5) at least one thermocouple for temperature measurement is placed near the reburn burner, preferably above the radiant fiber shield, and the temperature is controlled by the combustion There are some afterburning burners characterized in that they act on a surface that controls the supply of fuel to the afterburning burner. The steam generator described in . (6) A re-combustion burner is combined with a temporary installation that supplies air to maintain combustion. The steam generator according to any one of the above items (1) to (5). (Characterized in that it is applied to the combustion of waste fuel as at least some re-burning burner.The steam generating temporary storage according to any one of the above items (1) to (6)) .