JP3028466B2 - Moving bed granular dust collector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving bed granular dust collecting apparatus suitable for collecting high temperature and high pressure gas. In coal-fired power generation, a pressurized fluidized bed (P) is used to improve the efficiency of a power plant using a conventional steam turbine as a prime mover.
A combined power generation system of a gas turbine and a steam turbine using FBC (combustion gas) is being developed. On the other hand, since pressurized fluidized bed (PFBC) combustion gas contains a large amount of dust such as coal ash, it is necessary to remove the dust and supply it to a gas turbine. The present invention relates to a pressurized fluidized bed (PFBC)
This is a dust collector that removes dust from high temperature and high pressure gas such as combustion gas.

[0002]

2. Description of the Related Art Heretofore, this type is as follows. In the removal of dust in high-pressure high-temperature gas, three types, a mechanical cyclone dust collecting method, an electric dust collecting method, and a filter dust collecting method, are usually used.

[0003]

The above-mentioned prior art has the following problems. In the mechanical cyclone dust collecting method, the collection efficiency is reduced below about 10 μm, and in the bag filter generally used in the electric dust collecting method and the filter dust collecting method, the temperature is 850 ° C. to 1,000 ° C. Not applicable to hot gases. With the development of the pressurized fluidized bed (PFBC) power generation system, porous ceramic filters have been used,
Although suitable for heat resistance, the amount of compressed air for backwashing to prevent clogging of the ceramic filter increases,
In addition, damage and deterioration are inevitable due to repeated thermal shock due to the temperature difference between the combustion gas and air during backwashing. further,
Calcium oxide contained in the dust in the combustion gas when the gas temperature at the time of backwashing or during low load is reduced in the vicinity of 700 ° C., re-carbonation _{(CaO + CO 2 → CaCO 3} ) CaCO 3 was re-carbonation sessile Causes a fatal trouble of the ceramics filter. In the case of ceramic filters suitable for heat resistance as described in the prior art, there is an unavoidable problem that the amount of compressed air for backwashing increases and the sticking property due to recarbonation of calcium oxide in dust is inevitable. In view of the current situation where a power plant is not functioning sufficiently, it is intended to provide the following. In the above, the present invention accommodates the cyclone dust collecting part and the annular moving bed granular filter 8 in one pressure-resistant container from the viewpoint of heat resistance, pressure resistance and economy so as to be suitable for high-temperature and high-pressure gas. When transporting and circulating the high-temperature filter particles to form the particles, it is desirable not to lower the temperature in the particle transport section. Also, when applying an electric field to the granular filter to improve the dust collection efficiency,
It is necessary to form a heat-resistant electrode on the ceramic ring.

[0004]

Means for Solving the Problems In order to achieve the above object, the present invention is as follows. In order to solve the above-mentioned problem, a cyclone dust collecting part and one or more annular moving bed granular filters 8 are combined and housed in one cylindrical pressure-resistant container in view of heat resistance, pressure resistance and economy. . Conventionally, in a moving bed granular filter that has been developed, the flow of gas and the flow of particles have a cross flow as shown in FIG. 1, and the horizontal cross section has a rectangular shape. In this case, in the case of a high-temperature gas, it is difficult to use ceramics as a structural material when the inflow surface and outflow surface of the gas holding the particle-filled portion are enlarged. In the present invention, an annular moving bed granular filter 8 is formed as a cylindrical shape, which is the easiest shape in ceramics production. In the rectangular filter as shown in Figure 1 is conventional, the movement of the particles forming the moving bed as shown in FIG. 2, the faster gas flow velocity Vg ₁ shown in FIG. 3, at the Vg _2, mobile As for the particle movement speed Vm in the layer, the particles on the outflow side receive side pressure due to the gas flow velocity, the curve shifts from the solid line to the dotted line, and the movement of downstream particles is hindered. The pressure loss ΔP in the moving bed is shown in FIG.
As shown in (1), there was a drawback that dust was accumulated due to stagnation of particles on the outflow side and pressure loss was increased. In the present invention,
In the annular moving bed granular filter 8 shown in FIGS. 5, 6 and 7, when gas flows in from the inner cylindrical tube of the granular filter and flows out to the outer cylindrical tube of the granular filter, the gas flow rate Vg on the outflow side is circular. Because it decreases in inverse proportion to the inner diameter of the ring part,
Particle stagnation and an increase in pressure loss on the gas outflow side of the above-described rectangular moving layer can be suppressed. In the present invention, when the gas dust and the filter particles collected in the filter form a moving layer and are discharged from the casing, the mixed powder and dust particles are untreated before the gas passes through the filter. This is a method in which gas is transported by gas flow and transported to the granular material classifier 13 in the upper part of the casing, and other compressed air is not required. The electrode for applying an electric field to the granular filter was formed by depositing a spiral (vortex) and band-shaped conductive film on the inner surface of the ceramic annular portion by metal vapor deposition.

The above is summarized as follows. That is, the first invention is as follows. In the cleaning of a high-temperature pressure gas such as a pressurized fluidized bed combustion gas, a cyclone dust collecting part 4 and an annular moving bed granular filter 8 are housed in a casing 1 which is a pressure-resistant container, and the gas passing through the cyclone dust collecting part 4 is The moving bed granular filter 8 is introduced into the granular filter inner cylindrical tube 6 of the annular moving bed granular filter 8, and the moving bed granular filter 8 is a double tube of the granular filter inner cylindrical tube 6 and the granular filter outer cylindrical tube 7 on the same axis. The filter is filled with filter particles in the annular portion, and the cylindrical portion has ventilation holes through which the filter particles do not leak due to the gas flow rate, and the particles form a moving layer in the annular portion. Then, the annular moving bed granular filter 8 introduces gas from the cylindrical tube side of the granular filter,
By flowing out from the particulate filter outer tube side, the gas flow velocity in the moving bed becomes slow in inverse proportion to the inner diameter in the annular part, so that the side pressure received by the filter particles due to the gas flow velocity is reduced, and the particle movement is reduced. Prevents inhibition and the dust trapped between the filter particles, together with the filter particles,
It is discharged from the casing 1, passed through the particulate material flow control valve 11, and air-flowed to the particulate material classifier 13 by the gas diverted from the gas inlet 2 to separate dust and filter particles.
The dust is collected by an ordinary low-pressure dust collector via a pressure reducing expansion valve 15, and the filter particles are supplied to an annular moving bed granular filter 8 via a seal valve 14. It is a dust device. In this case, it can be configured as follows. When the processing gas amount is large, a plurality of sets of the cyclone dust collecting part 4 and the annular moving bed granular filter 8 are housed in the same casing. The second invention is as follows. The surface in contact with the filter particles in the moving bed granular filter 8 of dust collecting efficiency given field in order to improve the Rutoki, ceramic particulate filter in the cylinder tube 6 and the particulate filter outer cylindrical tube 7 in the first invention, the metal熔An electrode is formed by vapor-depositing a strip-shaped conductive film by irradiation, and a cyclone dust collecting unit and a moving-layer granular filter 8 formed in an annular shape are housed in a single pressure-resistant container. By introducing gas from the inner cylinder tube side, the movement of particles in the filter is prevented from moving on the filter wall on the outflow side, and dust and filter particles are transported and moved using a part of the combustion gas. because of the electrodes given an electric field to the layer particulate filter is a moving bed granular dust collecting device with metallized conductive film by metal thermal spraying a ceramic surface.

[0006]

Embodiments of the present invention will be described with reference to the drawings. 5, 6 and 7, gas flows in from the gas inlet 2 in the tangential direction of the casing inner surface of the casing 1, which is a pressure-resistant container, and constitutes the cyclone dust collecting part 4. To separate coarse particles of
The fine powder dust accompanies the gas and passes through the particle filter penetration part 5 of the cyclone dust collecting part 4 or the moving bed granular filter 8.
At the lower end of the filter, it passes through the passage shown by the arrow shown in FIG. 5 and rises up the granular filter inner tube 6 of the moving bed granular filter 8 arranged above the cyclone dust collecting section 4 and flows into the moving bed granular filter 8. . The gas that has flowed into the filter flows out from the entire circumference of the granular filter outer tube 7 while reducing the flow velocity.
The granular filter inner cylinder tube 6 has a lattice-like shape shown in FIG. 2 or a vent hole having a diameter equivalent to the thickness of the inner cylinder tube through which gas and dust can pass so as to prevent leakage of filter particles. The granular filter outer tube 7 has a vent hole that can prevent the filter particles from flowing out accompanying the gas. Dust in the gas flowing into the moving bed granular filter is trapped between the filter particles, and the particles and dust form a moving bed,
In the annular moving layer, the movement of particles in the annular portion is not hindered by the gas flow rate decreasing on the outer peripheral side.
The powder having the moving layer formed thereon is discharged from the lower part of the casing 1 by controlling the flow rate of the powder and particle flow regulating valve 11, and the gas diverted from the gas inlet 2 is controlled by the gas flow regulating valve 12 to control the powder. The granules are carried by air flow. The pneumatically transported powder fluid is transported to a powder classifier 13 to separate the powder (dust) and particles, and the particles are supplied to the moving bed granular filter 8 via a seal valve 14. Further, the powder (dust) accompanies the gas, and the gas is depressurized and reduced through the decompression expansion valve 15.
The dust is collected by an ordinary electric precipitator or a bubble filter, and the gas is heat-recovered in the exhaust heat recovery unit 26 on the steam turbine side in the pressurized fluidized bed (PFBC) power plant shown in FIG. In the case of a large-capacity power plant having a large amount of processing gas, as shown in FIG. 9, the annular moving bed granular filter 8 is accommodated in a common casing as a plurality of sets. In FIG. 10, a dust collector for high temperature and high pressure gas according to the present invention is provided with a pressurized fluidized bed (PF).
BC) A case where the present invention is applied to a power plant will be described. In addition,
In this drawing, the steam heating unit and the heat recovery unit are partially omitted. The pressurized fluidized bed (PFBC) combustion furnace 21 supplies coal and lime from a coal and lime supply unit 22, and supplies compressed air for combustion to a compressed air supply unit 28 for combustion from a gas turbine.
Pressurized fluidized bed (PFBC) combustion gas is supplied to a combustion gas outlet 23.
Effluent, and a high-temperature and high-pressure gas dust collector 24 according to the present invention.
The gas that has flowed in from the gas inlet 2 and has been dusted out flows out of the gas outlet 3 and is supplied to the gas turbine power generator 25. The exhaust gas of the gas turbine is supplied to an exhaust heat recovery unit 26, and the gas used for conveying the granular material in the dust collector for high-temperature and high-pressure gas passes through a low-pressure dust collector 16 and a low-pressure gas outlet 17. The heat is recovered by being supplied to the waste heat recovery unit 26,
The exhaust heat is effectively used by the steam turbine power generator 27. In moving bed granular filter 8, the Rukoto giving an electric field to the granular filter, has the effect of improving the dust collection efficiency, in the present invention, the particulate filter cylinder tube constituting the annular filter 6 and particulate filters out Since the cylindrical tube 7 is made of ceramics and is non-conductive, a spiral and band-shaped conductive film shown in FIG. 8 is deposited on the surface in contact with each particle by metal spraying to form a filter outer cylindrical tube (inner surface). ) An electrode 9a and a filter inner tube (outer surface) electrode 9b are formed, and drawn out of the casing 1 by a lead wire 10,
To so that given the electric field from the outside.

[0007]

Since the present invention is configured as described above, the following effects can be obtained. Combined cycle power generation using pressurized fluidized bed (PFBC) has been developed as a means for further improving the efficiency of coal-fired power generation. However, in the currently developed pressurized fluidized bed (PFBC) power generation, dust in combustion gas is removed. Uses a ceramic filter. In the use of a ceramics filter, there is a problem that calcium oxide scattered by desulfurization in a fluidized bed furnace is unavoidable to be recarbonated and fixed by the ceramics filter. The present invention uses an annular moving bed granular filter 8 as a main component to prevent a stagnation phenomenon of particle movement due to a gas flow rate, and also to use a combustion gas for carrying a gas stream for forming a particle circulation system of a moving bed. By using a diverted stream, no other compressed air source is required, and an electric field is applied to the particles to improve dust collection efficiency.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating the flow of gas and particles in a moving bed granular filter.

FIG. 2 is a longitudinal sectional view of a moving bed granular filter.

FIG. 3 is an explanatory diagram illustrating a layer thickness of particles and a particle moving speed in FIG.

FIG. 4 is an explanatory diagram illustrating a layer thickness of particles and a pressure loss during dust collection in FIG. 2;

FIG. 5 is a longitudinal sectional view of a dust collector for high-temperature and high-pressure gas.

FIG. 6 is a horizontal sectional view of an annular moving bed particle filter section of the dust collector for high-temperature and high-pressure gas.

FIG. 7 is a horizontal sectional view of a cyclone dust collecting unit of the dust collecting apparatus for high-temperature and high-pressure gas.

FIG. 8 is a schematic view of a particle filter electrode .

FIG. 9 is a horizontal sectional view when a plurality of sets of annular moving bed granular filters are combined with a cyclone dust collecting unit.

FIG. 10 is a configuration diagram of a pressurized fluidized bed (PFBC) power generation to which a moving bed granular dust collector is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Gas inlet part 3 Gas outlet part 4 Cyclone dust collecting part 5 Particle filter penetration part 6 Granular filter inner tube 7 Granular filter outer tube 8 Moving layer granular filter 9a Filter outer tube (inner surface) electrode 9b Filter inner tube Pipe (outer surface) electrode 10 Lead wire 11 Powder flow regulating valve 12 Gas flow regulating valve 13 Powder classifier 14 Seal valve 15 Pressure reducing expansion valve 16 Low pressure dust collector 17 Low pressure gas outlet 21 Pressurized fluidized bed (PFBC) ) Combustion furnace 22 Coal and lime supply section 23 Combustion gas outlet section 24 Dust collector for high-temperature and high-pressure gas 25 Gas turbine power generator 26 Exhaust heat recovery section 27 Steam turbine power generator 28 Compressed air supply section for combustion

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI B01D 50/00 502 B01D 50/00 502Z

Claims (3)

(57) [Claims] In cleaning a high-temperature gas such as a pressurized fluidized-bed combustion gas, a casing (1) that is a pressure-resistant container is provided with:
The cyclone dust collecting part (4) and the annular moving bed granular filter (8) are housed therein, and the gas that has passed through the cyclone dust collecting part (4) is supplied to the cylindrical cylindrical pipe of the annular moving bed granular filter (8). Introduced in (6), the moving bed granular filter (8) is an annular portion composed of a double tube of a granular filter inner cylindrical tube (6) and a granular filter outer cylindrical tube (7) which are coaxial. The cylindrical portion has a ventilation hole through which the filter particles do not leak due to the gas flow rate, and the particles are configured to form a moving layer in the annular portion. The gas flow in the moving bed becomes slower in inverse proportion to the inner diameter in the annular portion by introducing gas from the inner tube side of the granular filter and flowing out the gas from the outer tube side of the granular filter. The gas flow rate To reduce the lateral pressure applied to the filter particles, thereby preventing the movement of the particles. The dust collected between the filter particles is discharged from the casing (1) together with the filter particles, and the powder flow control valve (11) is installed. After that, the gas diverted from the gas inlet part (2) is carried by air flow to the particulate classifier (13) to separate dust and filter particles, and the dust passes through the decompression expansion valve (15), and is subjected to ordinary low pressure dust collection. A moving bed granular dust collecting apparatus characterized in that dust is collected by a vessel and filter particles are supplied to an annular moving bed granular filter (8) via a seal valve (14). 2. A moving bed granular collector according to claim 1, wherein a plurality of sets of the cyclone dust collecting section (4) and the annular moving bed granular filter (8) are housed in the same casing when the processing gas amount is large. Dust equipment. 3. A given field in order to improve the dust collecting efficiency of the transfer layer granular filters in claim 1 (8) Rutoki, ceramic particulate filter in the cylinder tube (6) and the particulate filter outer cylindrical tube (7 A) a band-shaped conductive film was metal-deposited on the surface in contact with the filter particles by metal spraying to form an electrode , and a cyclone dust collecting portion and an annular shape were formed in a single pressure-resistant container. The moving bed granular filter (8) is housed, and the annular portion introduces gas from the cylindrical tube side of the granular filter, thereby preventing movement of particles in the filter on the filter wall on the outflow side and preventing combustion gas. Convey dust and filter particles using a part,
The electrode of the order given an electric field to the transfer layer particulate filters, moving bed granular precipitator, characterized in that to the metal depositing a conductive film by metal thermal spraying a ceramic surface.