JPH08134473A - Fluidized-bed gasifier - Google Patents

Abstract

PURPOSE: To regulate a gas yielded as a gasification product to have a concentration of alkali compounds which is not higher than a given value by using an alkali compound concentration meter and an alkali compound absorbent feeder in combination so as to perform a specific function. CONSTITUTION: A product gas 602 is continuously sampled by suction to determine the concentration of alkali compounds (Na+K) with an alkali compound concentration meter 80 by atomic absorption spectrometry. Signals 800 sent from the meter 80 are converted with a signal processor 81 to regulate the rotational speed of a screw feeder 8. Thus, the amount of ash particles introduced into an alkali compound absorbent particle layer 2 is regulated to thereby regulated the alkali compound concentration of the gas. When the gas sample has a high alkali compound concentration, the amount of the ash particles is increased to heighten the rate of alkali compound absorption. The gas 602 in which the content of the alkali compounds have been reduced to 50ppb or lower is subjected to precision dust removal with a ceramic filter 3. The resulting purified gas 603 is sent to a gas turbine 4 and used for power generation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed gasification apparatus for producing gasification gas from solid fuel such as coal for supplying to a gas turbine for power generation.

[0002]

2. Description of the Related Art An example of a conventional fluidized bed gasifier is shown in FIG.
Will be described below. The fluidized bed gasification furnace 1 constituting the fluidized bed gasification apparatus of FIG. 9 includes a desulfurization section 1a and a gasification section 1
b and an oxidation part 1c. Gasification section 1
b, coal 100 and combustion gas 600 from the oxidizer 1c
The fluidized bed 10b is formed by supplying c from the lower part of the gasification section. In the fluidized bed 10b, the air 401 serves as an oxidizing agent, and the combustion gas 600c from the oxidizing section 1c serves as a gasifying agent, so that a combustion / gasification reaction of the supplied coal 100 occurs. The gasified gas 600b generated in the gasification section 1b is sent to the desulfurization section 1a, and the unburned char is sent to the oxidation section 1c.

In the desulfurization section 1a, coal stone 200 is supplied from above, and the fluidized bed 10 is supplied by the gasification gas from the gasification section 1b.
a is formed. A desulfurization reaction of the gasification gas occurs in the fluidized bed 10a. The CaS and unreacted limestone 300a generated in the desulfurization section 1a are the unburned char 3 from the gasification section 1b.
It is sent to the oxidation part 1c with 00b.

In the oxidation part 1c, air 400 and steam 500 are supplied from the lower part, and CaS from the desulfurization part 1a and unreacted limestone 300a and unburned char 300b from the gasification part 1b form a fluidized bed 10c. In the fluidized bed 10c, a combustion reaction of unburned char and an oxidation reaction of CaS occur. The combustion gas 600c from the oxidizing section 1c is sent to the gasification section 1b, and the particles 301 are discharged.

Heat exchanger 70 and air 4 installed in the bed
By controlling the amount of 00, the temperature of the fluidized beds 10a-c is 90
It is controlled at 0 to 1100 ° C. The gasified gas 601 of 900 to 1000 ° C. generated in the fluidized bed 10a is the gas cooler 9
After being cooled to 450 ° C. at 0, it is dedusted by the cyclone 11. The dedusted gasified gas 603 is further precisely dedusted by the ceramics filter 3. 4 after precision dust removal
The gasified gas 604 at 50 ° C. is sent to the gas turbine 4 and used for power generation.

The gas 605 exiting the gas turbine 4 is sent to the exhaust gas boiler 5 and drives the steam turbine 6 by the heat recovered by the heat exchanger 71. Exhaust gas 606 emitted from the exhaust gas boiler 5 is discharged from the chimney 7 as exhaust gas 607.

[0007]

The gasification gas discharged from the fluidized bed gasification furnace contains alkali compounds such as sodium compounds and potassium compounds. Since the alkali compound in the gasification gas causes corrosion of the gas turbine, it is considered that the allowable concentration of the alkali compound in the gas is about 50 ppb or less at the gas turbine inlet.

In the prior art, in order to keep the alkali compound in the combustion gas below the allowable limit, the gasified gas was cooled to solidify the alkali compound and removed by dust removal. However, the conventional technique has a problem in that the efficiency of the gasification gas is lowered because the gasified gas is cooled. Therefore, it is necessary to remove the alkaline compound in the gasification gas that does not require cooling of the gasification gas.

According to the present invention, in a fluidized bed gasification apparatus for simultaneously desulfurizing a fuel in a fluidized bed, the concentration of the alkali compound in the produced gasified gas can be suppressed to a predetermined value. An object is to provide a gasifier.

[0010]

According to the present invention, a solid fuel is fluidized with an oxidizing gas containing oxygen together with a desulfurizing agent to form a fluidized bed, and the solid fuel is gasified in the fluidized bed. At the same time, the following constitution is adopted to solve the above-mentioned problems in the fluidized bed gasification apparatus which performs desulfurization.

That is, in the fluidized bed gasification apparatus according to the present invention, an alkali compound concentration measuring instrument for continuously measuring the concentration of the alkali compound contained in the gasification gas, and a supply amount based on a signal from the measuring instrument. An alkali compound absorbent supply device is provided for supplying the adjusted alkali compound absorbent composed of alumina (Al ₂ O ₃ ) and silica (SiO ₂ ) containing ash particles to the contact portion with the gasification gas.

In the fluidized bed gasification apparatus according to the present invention, the contact portion for contacting the alkaline compound absorbent with the gasified gas is an alkaline compound absorbing particle layer installed in the flow path of the gasified gas discharged from the fluidized bed gasification furnace. Can be
Alternatively, the contact portion may be a desulfurization portion in a fluidized bed gasification furnace.

As the alkali compound absorbent used in the present invention, ash particles generated in a coal burning boiler or ash discharged from the oxidizing part of the fluidized bed gas furnace may be used.

[0014]

Since the fluidized bed gasification apparatus according to the present invention has the above-mentioned structure, the alkali compound in the gasification gas from the fluidized bed gasification furnace can be mixed with the alkaline compound absorption particle bed or the desulfurization section of the fluidized bed gasification furnace. In the catalyst part such as the above, it comes into contact with alumina (Al ₂ O ₃ ) and silica (SiO ₂ ) in the alkali compound absorbent supplied from the alkali compound absorbent supply device, and mainly causes the following reaction.

As described above, the gasification gas is changed to alumina (Al
By contacting with ash particles containing ₂ O ₃ ) and silica (SiO ₂ ), the alkali compound in the gasification gas is captured by the ash particles, and the concentration of the alkali compound in the gas is reduced.

[0016]

[Equation 1]

In the fluidized bed gasifier according to the present invention, an alkali compound concentration measuring instrument is provided to continuously measure the concentration of the alkali compound contained in the gasification gas, and control is performed based on the signal from the measuring instrument. Since the absorbed amount of the alkali compound is supplied, it is possible to always maintain the concentration of the alkali compound in the gasification gas below a predetermined value.

[0018]

EXAMPLES A fluidized bed gasifier according to the present invention will be specifically described below based on the illustrated examples. In addition,
In the following examples, coal is used as a fuel, limestone is used as a desulfurizing agent, and coal is gasified by using air as an oxidizing gas. It is an example. Also, in the following examples,
The parts having the same configurations as those of the conventional plant shown in FIG. 9 are denoted by the same reference numerals for the sake of brevity, and duplicate description thereof will be omitted.

(First Embodiment) First, a first embodiment whose flowchart is shown in FIG. 1 will be described. In FIG. 1, 2 is an alkali compound absorption particle layer. The hopper 9 stores ash particles from the coal-fired boiler as described later. A screw feeder 8 sends ash particles in the hopper 9 to the alkaline compound absorption particle layer 2.

Reference numeral 80 is an alkali compound concentration measuring device, and 81
Is a signal processor for processing the signal 800 from the measuring device 80. The other configurations are substantially the same as the configurations of the fluidized bed gasifier shown in FIG. In the device of FIG.
Alumina (Al ₂ O ₃ ) and silica (S
ash particles (Al ₂ O ₃ : 30 wt%, SiO ₂ : 50 wt) generated in a coal-fired boiler (not shown) containing iO ₂ ).
%, Average particle size 300 μm) are stored. The ash particles 302 in the hopper 9 are guided to the screw feeder 8,
The ash particles 303 are sent to the alkali compound absorption particle layer 2 by the screw feeder 8.

The structure of the alkaline compound absorbing particle layer 2 is shown in FIG.
Is shown in. The alkali compound absorption particle layer 2 is composed of a dispersion plate 2b having a size of 200 mesh, an upper part 2a of the dispersion plate, an ash particle filling part 2c at the lower part of the dispersion plate, and an alumina ball filling part 2d having a particle diameter of 2 mm. The ash sent to the alkali compound absorption particle layer 2c comes into contact with the gasification gas 601 introduced from the upper part 2a of the dispersion plate, whereby the alkali compound in the gasification gas is mixed with alumina (Al ₂ O ₃ ) in the ash and Absorb on silica (SiO ₂ ).

Control of the concentration of the alkaline compound in the gasified gas is performed by continuously suction-sampling the gasified gas 602 in FIG. 1 and measuring the concentration of the alkaline compound (Na + K) by an atomic absorption method alkaline compound concentration measuring instrument 80. The signal 800 from the alkali compound concentration measuring device 80 is converted by the signal processor 81, the rotation speed of the screw feeder 8 is adjusted, and the ash particle supply amount into the alkali compound absorbing particle layer 2 is adjusted.

When the concentration of the alkali compound is high, the amount of ash particles supplied is increased to increase the absorption rate of the alkali compound.
The overflow ash 304 that has absorbed the alkaline compound is discharged and discarded. The gasified gas 602 from which the alkaline compound has been removed to 50 ppb or less in this way is precisely dusted by the ceramic filter 3. The gas 603 after the precision dust removal is sent to the gas turbine 4 and used for power generation.

Exhaust gas 604 from the gas turbine 4 is used for power generation by the exhaust gas boiler 5 and the steam turbine 6, and is discharged as combustion gas 606 by the chimney 7.
The mass balance in this example is shown in FIG.

(Second Embodiment) Next, the second embodiment shown in FIG. 4 will be described. In the second embodiment, the alkali absorbing particle bed of the first embodiment and the desulfurization section of the fluidized bed gasification furnace are integrated. The integration reduces the number of devices and simplifies the configuration.

In FIG. 4, as ash particles containing alumina (Al ₂ O ₃ ) and silica (SiO ₂ ), ash particles generated in a coal combustion boiler (not shown) are stored in a hopper 9, and ash particles are stored there. 302 is guided to the screw feeder 8, and the ash particles 303 are sent to the desulfurization section 10a of the fluidized bed coal gasification furnace 1 by the screw feeder 8.

The desulfurization section 10 is driven by the screw feeder 8.
The ash sent to a absorbs the alkali compound in the gasification gas into alumina (Al ₂ O ₃ ) and silica (SiO ₂ ) in the ash by contacting with the gasification gas 600b. The gasified gas 601 from which the alkaline compound has been removed is dedusted by the cyclone 11 and then precisely dedusted by the ceramics filter 3 and used for power generation. Other configurations and operations are similar to those of the first embodiment. The mass balance in this example is shown in FIG.

(Third Embodiment) Next, the third embodiment shown in FIG. 6 will be described. In the third embodiment, alumina (Al ₂
As ash particles containing O ₃ ) and silica (SiO ₂ ), the ash discharged from the oxidation part of the fluidized bed coal gasification furnace 1 which constitutes the fluidized bed gasifier is used. According to this structure, the ash discharged from the gasification furnace 1 can be recycled.

In FIG. 6, the oxidation part 1 of a coal gasification furnace 1 containing alumina (Al ₂ O ₃ ) and silica (SiO ₂ ).
Ash discharged from c (Al ₂ O ₃ : 25 wt%, SiO ₂ : 4:
2 wt% and an average particle size of 500 μm) are stored in a hopper 9, and a part 302 thereof is sent to the desulfurization section 10a of the fluidized bed coal gasification furnace 1 by the screw feeder 8 (303). The remaining ash 301 is discharged and discarded.

The desulfurization section 10 is driven by the screw feeder 8.
The ash sent to a absorbs the alkali compound in the gasification gas into alumina (Al ₂ O ₃ ) and silica (SiO ₂ ) in the ash by contacting with the gasification gas 600b. The gasified gas 601 from which the alkaline compound has been removed is dedusted by the cyclone 11 and then precisely dedusted by the ceramics filter 3 and used for power generation. The mass balance in this example is shown in FIG.

[0031]

According to the fluidized bed gasification apparatus of the present invention, the alkali compound concentration measuring device and the contact portion of the supply amount of the alkali compound absorbing substance adjusted on the basis of the signal from the measuring device are brought into contact with the gasifying gas. Since it has an alkaline compound absorbent supply device for supplying the alkaline compound in the gasification gas, the alkaline compound in the gasification gas is absorbed and removed by the alkaline compound absorbent at its contact portion, and the alkaline compound concentration can be kept below a predetermined value. .

The effect of contact with ash particles according to the invention on the concentration of alkali compounds in the combustion gas is shown in FIG. From FIG. 8, it can be seen that the concentration of the alkaline compound in the gasified gas is greatly reduced as compared with the conventional case. Moreover,
Since the plant of the present invention does not cool the gasified gas, the efficiency is increased as compared with the conventional case (1 to HHV standard).
2%). As described above, according to the present invention, it is possible to reduce the amount of alkali compounds in the gasification gas without causing a decrease in efficiency.

[Brief description of drawings]

FIG. 1 is a drawing showing a flowchart of a fluidized bed gasifier according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of an alkaline compound absorption device used in the device according to the first embodiment of FIG.

FIG. 3 is a chart showing mass balance in the fluidized bed gasifier according to the first embodiment of the present invention.

FIG. 4 is a drawing showing a flowchart of a fluidized bed gasification apparatus according to a second embodiment of the present invention.

FIG. 5 is a chart showing mass balance in a fluidized bed gasifier according to a second embodiment of the present invention.

FIG. 6 is a drawing showing a flowchart of a fluidized bed gasification apparatus according to a third embodiment of the present invention.

FIG. 7 is a chart showing mass balance in a fluidized bed gasification apparatus according to a third embodiment of the present invention.

FIG. 8 is a drawing showing the concentration of alkali compounds in a gasification gas obtained by a fluidized bed gasification apparatus according to an example of the present invention.

FIG. 9 is a view showing a conventional fluidized bed gasifier.

[Explanation of symbols]

1 fluidized bed coal gasification furnace 1a desulfurization part 1b gasification part 1c oxidation part 2 alkali compound absorption particle layer 2a dispersion plate upper part 2b dispersion plate 2c ash particle filling part 2d alumina ball filling part 3 ceramics filter 4 gas turbine 5 exhaust gas boiler 6 Steam turbine 7 Chimney 8 Screw feeder 9 Hopper 10a, 10b, 10c Fluidized bed 11 Cyclone 70, 71 Heat exchanger 80 Alkali compound concentration measuring instrument 81 Signal processor 90 Gas cooler 100 Coal 200 Limestone 300, 301, 302, 303, 304, 305, 3
00a, 300b Ash (including char and unreacted limestone) 400, 401, 402 Air 500 Steam 600b, 600c, 601, 602, 603, 60
4,605,606,607 Gasification gas or combustion gas 800,801 Electric signal

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location C10K 1/32 (72) Inventor Satoshi Jin 2-5-1, Marunouchi, Chiyoda-ku, Tokyo Sanryo Heavy Industry Co., Ltd. (72) Inventor, Katsuhiko Shinoda, Sanchiro Heavy Industries Co., Ltd., 2-5-1, Marunouchi, Chiyoda-ku, Tokyo

Claims (3)

[Claims] 1. A solid fuel with an oxygen-containing acid together with a desulfurizing agent.
Fluidized with activated gas to form a fluidized bed,
The solid fuel is gasified and simultaneously desulfurized.
In a fluidized bed gasifier
Alkali compounds that continuously measure the concentration of alkaline compounds
Supply based on the substance concentration measuring instrument and the signal from the measuring instrument
Adjusted amount of alumina (Al₂O₃) And silica
(SiO ₂) Alkaline compounds composed of ash particles
Alkaline compound that supplies the absorbent to the contact area with gasification gas
Fluidized-bed gas characterized by having a material absorber supply device
Device. 2. The fluidized bed gasification apparatus according to claim 1, wherein the contact portion is composed of an alkali compound absorbing particle layer installed in a gasification gas flow path exiting from a fluidized bed gasification furnace. 3. The fluidized bed gasification apparatus according to claim 1, wherein the contact portion is a desulfurization portion of a fluidized bed gasification furnace.