JP3999995B2 - Dry smoke purification system - Google Patents

Description

[0001]
[Industrial application fields]
The present invention is a dry flue gas purification system for removing sulfur oxide (SOx), nitrogen oxide (NOx), and soot and dust in flue gas, and has been used in the past. Compared to the combination of the device and the dust collector, it is low cost.
[0002]
[Prior art]
Conventionally, in flue gas desulfurization, the lime gypsum method has been widely used for large-capacity flue gas desulfurization devices, and the magnesium hydroxide method (water mug method) has been adopted for medium- and small-capacity flue gas desulfurization devices.
The above two methods are both wet methods, use a large amount of water and reheat the flue gas temperature, but it is 100 ° C to 90 ° C, and the normal boiler discharge temperature is 140 ° C to Since it falls from 130 degreeC, it has the fault that the effective raise height of flue gas becomes low.
Dry flue gas desulfurization has the advantages that there is no drainage to the outside of the device and the temperature of the flue gas does not decrease, but the cost of the device is higher than that of the wet method. (2002) As a practical machine, there are only two examples in a thermal power plant, one example using the coal ash / lime desulfurization method and one example using the activated carbon method.
[0003]
[Problems to be solved by the invention]
The dry type flue gas purification system of the present invention provides a dry type flue gas purification system that can sufficiently compete with the combination of the wet desulfurization device and the dust collector in the prior art. In the conventional dry-type flue gas purifying apparatus, in the solid-gas reaction between the absorbent and the flue gas, the absorbent is granulated and brought into solid-gas contact as a cross-flow moving layer. In order to suppress an increase in pressure loss when passing through the moving layer of the flue gas, the particle size distribution of the absorbent should be about 5 to 9 mm to avoid mixing of powders, and the gas flow rate should also be 0.4. Since the low speed is set to ˜0.6 m / sec, the moving bed of the solid-gas reactor becomes large. For this reason, the manufacturing cost of the absorbent and the solid-gas reactor (SOx / NOx absorption tower) cost have been increasing factors.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides the following configurations. The invention according to claim 1 is a dry type flue gas purification system for removing sulfur oxide (SOx) and nitrogen oxide (NOx) in flue gas with a powder absorbent for desulfurization / denitration. And
A spouted bed reactor installed on the upstream side and a moving bed reactor installed on the downstream side,
The spouted bed reactor has a gas inlet to the reactor body, the reactor body from the gas inlet, allowed to flow into a desulfurization and denitration powder absorber with flue gas, wherein the reactor body in the while being configured so as to perform the desulfurization and denitration of flue gases, the reactor body is configured in multiple stages, comprises a cyclone for collecting the desulfurizing DeNOx powder absorbent to each stage, the the powder absorbent for desulfurization and denitration were collected by the cyclone is conveyed in front of the upstream side of the reactor main body is configured to reuse,
The moving bed reactor includes a moving bed filled with particles in the reactor main body , and the desulfurization / denitration powder absorbent flowing out together with the flue gas from the spouted bed reactor is transferred to the particles of the moving bed . is penetrated by collecting in between, by the mobile phase was collected powder absorbent for the desulfurization and denitrification, causes rope rows desulfurization and denitrification of the flue gas, Soot dust the flue gas it is intended to provide a dry flue gas purification system, characterized in that is configured to make collect.
Further, the configuration of the present invention will be described.
(1) The absorbent was a powder that had nothing to do with yield reduction for producing granules.
(2) By using powder, application of the spouted bed can be facilitated, and the flow rate of the flue gas can be 4 m / sec or more.
(3) In consideration of dust collection of the powder absorbent, it shall be based on a granular moving layer, the moving layer has a double ring structure, and the exhaust gas inflow rate is 0.8 m / sec or more. This makes it possible to reduce the size of the cross-flow moving bed. For the cross-flow moving bed having a double annular structure, “moving bed granular dust collector, Japanese Patent No. 3028466 / February 4, 2000” is incorporated.
(4) Conventionally, there is a method of forming a SOx absorption part by forming a powder layer on the surface of the bag filter using a powder filter with a powder absorbent, but when using the bag filter, it flows into the bag filter. Since the speed is usually 1.6 to 2 cm / second, the certainty of adhesion of the powder to the bag filter cannot be obtained, so that the utilization rate of the desulfurizing agent is lowered.
(5) The powder absorbent has a desulfurization efficiency of 90% or more and a denitration efficiency of 60% or more when the Ca utilization rate (Ca / S) is 70 to 60% or less for desulfurization. (See Figure 1)
(6) In the present invention, since the particle moving layer is applied, the inflow rate of the flue gas is set to 80 cm / second or more, so that the powder absorbent can surely penetrate between the moving layer particles. And can contribute to desulfurization and denitration reactions.
[0006]
【Example】
A dry smoke purification system of the present invention will be described with reference to FIG.
2, 3, and 4, each part of 1 to 8 </ b> A is a powder absorbent manufacturing apparatus, and each part of 9 to 18 is a flue gas treatment apparatus.
The raw material for the production of the powder absorbent is a quick lime (CaO) silo 1 and a coal ash silo 2, powder is measured with a quick lime meter 1 A and a coal ash meter 2 A, and after passing through a powder mixer 4, a kneader 5 The kneaded water is kneaded with water supplied from the water supply tank 3 from the water supply meter 3A. The amount of water supply at this time is the theoretical water amount (CaO + H ₂ O → Ca (OH) ₂ when CaO is added to quick lime (CaO) to form calcium hydroxide (Ca (OH) ₂ ), with respect to CaO, 1.0. H ₂ O, 0.32) is 1.5 times or more.
[0007]
The kneaded product is cured by hydration curing in the hydration curing apparatus 6 at a humidity of 100% and a temperature of 80 to 98 ° C. A powdery absorbent is produced from the hydrated cured product by the crushing and drying machine 7 and stored in the absorbent silo 8. The powder absorbent is supplied from the absorbent supply unit 8A according to the concentration of sulfur oxide (SOx) in the flue gas, and flows into the spouted bed reactor 10 from the gas inflow portion 9 together with the flue gas , and the flue gas Desulfurization / denitration reaction with gas. The flue gas exhausted from the spouted bed reactor 10 is supplied to a double annular moving bed reactor 11. The moving bed particles 11C packed in the moving bed reactor 11 are supplied from the particle supply unit 11D and discharged from the particle discharge unit 11E at the lower part of the moving bed reactor 11, so that the moving bed particles move from the upper part to the lower part. A moving layer is formed.
[0008]
On the other hand, the flue gas cross-flows in the moving bed from the inner tube portion 11A of the moving bed reactor 11 to the outer tube portion 11B. The powder absorbent accompanying the flue gas penetrates between the moving bed particles, is collected in the moving bed, and absorbs SOx / NOx in the flue gas in the moving bed.
The used powder absorbent that has absorbed SOx / NOx is discharged together with the moving bed particles 11C from the particle discharge section 11E, and the used powder absorbent and the moving bed particles 11C are separated by the classifier 12, and the moving bed particles are separated. 11C is pneumatically transported to the particle supply unit 11D located above the granular material moving layer 11 by the particle transport unit 14 and the particle transport fan 14A, and is used in a circulating manner.
The exhaust gas exhausted after being purified by the moving bed reactor 11 is discharged to the atmosphere from the chimney 16 through the induction fan 15.
[0009]
When the spouted bed reactor 10 is configured as a first stage spouted bed reactor 10A, a second stage spouted bed reactor 10B, and a third stage spouted bed reactor 10C in the multistage configuration shown in FIG. The powder desulfurization agent is collected by 10D, and the powder desulfurization agent is conveyed to the upstream upstream side to improve the utilization rate of the desulfurization agent. That is, the flue gas flows through each spouted bed reactor of 10A → 10B → 10C, and the powder desulfurizing agent is conveyed through the spouted bed reactor of each stage of 10C → 10B → 10A, and the solid-gas reaction is opposed as a whole. It becomes a flow reaction. As shown in FIG. 1, the absorbent using coal ash and calcium as a raw material has a SOx / NOx simultaneous absorption performance at a Ca utilization rate (Ca / S) of 60 to 70% or less in desulfurization. It can be applied as a denitration agent. In FIG. 1, when the solid-gas reaction is 20 hours or longer, the denitration performance is lowered, and only the desulfurization performance is obtained.
[0010]
【The invention's effect】
Conventionally, dry desulfurization uses less water and does not produce drainage. In addition, while having the advantage of not lowering the flue gas temperature, it was not popular due to its high cost compared to wet desulfurization. The dry type flue gas purification system according to the present invention has a combined function of desulfurization, denitration, and dust collection, is economical and can sufficiently resist wet desulfurization, and can contribute to global environmental conservation.
[Brief description of the drawings]
[Fig. 1] SOx / NOx absorption characteristics of absorbent in fixed bed [Fig. 2] Dry flue gas purifier configuration diagram [Fig. 3] Cross section of moving bed reactor X1-X1 '[Fig. 4] Moving bed reactor X2- X2 'cross section [Fig. 5] Multistage spouted bed configuration [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Quick lime (CaO) silo 1A Quick lime meter 2 Coal ash silo 2A Coal ash meter 3 Water tank 3A Water meter 4 Powder mixer 5 Kneader 6 Hydration curing device 7 Crushing dryer 8 Absorber silo 8A Absorbent Feeder 9 Gas inflow part 10 Spouted bed reactor 10A First stage spouted bed reactor 10B Second stage spouted bed reactor 10C Third stage spouted bed reactor 10D Cyclone 11 Moving bed reactor 11A Moving bed inner cylinder part 11B Layer outer cylinder part 11C Moving bed particle 11D Moving bed particle supply part 11E Moving bed particle discharge part 12 Classifier 13 Used desulfurization agent silo 14 Particle conveying part 14A Particle conveying fan 15 Induction fan 16 Chimney

Claims (1)

A dry smoke purification system for removing sulfur oxide (SOx) and nitrogen oxide (NOx) in flue gas with a powder absorbent for desulfurization and denitration,
A spouted bed reactor installed on the upstream side and a moving bed reactor installed on the downstream side,
The spouted bed reactor has a gas inlet to the reactor body, the reactor body from the gas inlet, allowed to flow into a desulfurization and denitration powder absorber with flue gas, wherein the reactor body in the while being configured so as to perform the desulfurization and denitration of flue gases, the reactor body is configured in multiple stages, comprises a cyclone for collecting the desulfurizing DeNOx powder absorbent to each stage, the the powder absorbent for desulfurization and denitration were collected by the cyclone is conveyed in front of the upstream side of the reactor main body is configured to reuse,
The moving bed reactor includes a moving bed filled with particles in the reactor main body , and the desulfurization / denitration powder absorbent flowing out together with the flue gas from the spouted bed reactor is transferred to the particles of the moving bed . is penetrated by collecting in between, by the mobile phase was collected powder absorbent for the desulfurization and denitrification, causes rope rows desulfurization and denitrification of the flue gas, Soot dust the flue gas dry flue gas purification system, characterized by being configured to make collect.

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