JPH0975661A - Exhaust gas treatment equipment of olimulsion firing boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively remove SO3 from the combustion exhaust gas of olimulsion by providing an SO3 removing device bringing CaCO3 into contact with the combustion exhaust gas passing through the duct connecting a denitration device and a dust collector to remove SO3 in the exhaust gas to the duct. SOLUTION: The exhaust gas generated in an olimulsion firing boiler 1 passes through a denitration device 2 to remove NOx contained in the exhaust gas. This exhaust gas is cooled by heating combustion air by an air preheater 3 to pass through the moving bed of an SO3 removing device A through a duct D. At this time, SO3 contained in the exhaust gas is reacted with the CaCO3 powder flowing through the moving bed to be separated as CaSO4 from the exhaust gas. By this constitution, SO3 is prevented from being discharged to the atmosphere as it is. The exhaust gas, clear of SO3 4, is cleared of soot in the exhaust gas by a dust collector 4. This exhaust gas is cooled by a heat exchanger 5 to be brought into contact with an absorbing soln. in a desulfurizer 6 and discharged as purified gas from which SO3 and SO2 are removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flue gas treatment facility provided in a thermal power plant and a boiler of a refuse incineration facility,
In particular, the present invention relates to a flue gas treatment equipment for an orimulsion-fired boiler that uses orimulsion containing a large amount of SO ₃ as a fuel.

[0002]

2. Description of the Related Art Conventionally, a boiler used in a thermal power plant or a refuse incineration facility is provided with a flue gas treatment facility for removing and discharging harmful substances contained in combustion exhaust gas. . As this flue gas treatment facility, for example, as shown in FIG. 4, a denitration device 2, an air preheater 3, an electrostatic precipitator 4, a heat exchanger 5, and a wet desulfurization device 6 are provided on a downstream side of the boiler 1 by a duct D. It is configured by connecting in order. Then, first, the high temperature combustion exhaust gas generated in the boiler 1 is removed by the denitration device 2
After removing nitrogen oxides such as NO _x contained in the exhaust gas, the air preheater 3 exchanges heat with the combustion air to cool it, and then the air preheater 3 cools it. After the soot and dust in the exhaust gas that has been removed is removed by a dust collector 4 such as an EP or a bag filter, it is further cooled by a heat exchanger 5, and finally, by a wet desulfurization device 6, the remaining SO ₂ contained in the exhaust gas. It is designed to be released into the atmosphere after being removed. Then, the sulfur content in the desulfurization wastewater absorbed by the desulfurization device 6 is sent to a wastewater treatment device (not shown) and is recovered as a sulfate or a sulfite.

[0003]

By the way, the boiler provided in the conventional flue gas treatment facility as described above mainly uses fossil fuels such as coal and petroleum. Instead of general fossil fuels, a fuel called Orimuljeon is drawing attention. This new fuel called Orimuljeon is available at a lower cost than conventional fossil fuels, and it is confirmed that it is a highly stable fuel in practice, despite being a water emulsion fuel. ing. However, since this orimulsion contains a large amount of SO ₃ in the combustion exhaust gas as compared with conventional fossil fuels, when this is burned in the boiler 1 of the conventional flue gas treatment facility, this SO ₃ becomes wet. There is a problem that it is not captured by the desulfurization device and is released into the atmosphere as it is.

Therefore, as shown in FIG. 4, NH ₃ is injected into the duct D in front of the dust collector 4, and NH ₄ HSO ₄ ,
A method of recovering (NH ₄ ) ₂ SO ₄ from the exhaust gas is conceivable. Then, the NH ₄ HSO ₄ , (N
If H ₄ ) ₂ SO ₄ adheres to the dust collector 4 and the heat exchanger 5 and corrodes them, or if NH ₄ ⁺ is mixed into the coal ash and desulfurization wastewater, they are further separated. There are new problems such as the fact that it must be removed by the above method.

Therefore, the present invention has been devised in order to effectively solve such a problem, and its purpose is to provide a novel orimulsion capable of effectively removing SO ₃ from the combustion exhaust gas of the orimulsion. It is intended to provide flue gas treatment equipment for a fired boiler.

[0006]

In order to solve the above problems, the present invention removes nitrogen oxides in the combustion exhaust gas of a boiler downstream of a boiler that burns orimulsion that generates a large amount of SO _3. Denitration device, dust collector for removing soot and dust in exhaust gas after denitration, and SO in exhaust gas after dust removal
_In a flue gas treatment facility for an Orimuljon-fired boiler in which a desulfurization device for removing ₂ is connected by a flue gas duct, CaCO ₃ is contacted with the exhaust gas passing through this duct in the duct connecting the denitration device and the dust collector. The SO ₃ removing device for removing SO ₃ in the exhaust gas is provided.

As a result, SO ₃ in the exhaust gas is effectively removed in front of the dust collector, so that corrosion of the dust collector and the heat exchanger on the downstream side is prevented and the SO ₃ in the atmosphere is removed. Dramatically reduce the amount of SO ₃ released.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a preferred embodiment of the flue gas treatment equipment for an orimulsion-fired boiler according to the present invention.
Orimulsion-fired boiler using Orimulsion in 1 described above figure as fuel, 2 denitration apparatus for removing NO _X in the combustion exhaust gas, 3 preheater for preheating the combustion air by the heat of the exhaust gas, A is SO ₃ in the exhaust gas To remove SO
₃ removal device, 4 is a dust collector for removing soot and dust in exhaust gas, 5
Is a heat exchanger for cooling the exhaust gas, 6 is a wet desulfurization device for spraying an absorbent to remove SO ₃ and SO ₂ in the exhaust gas, D
Is a duct that connects these to each other and serves as an exhaust gas flow path. Of these ducts, except the SO ₃ removing device A, the duct has a substantially similar structure to the conventional one.

In this SO ₃ removing apparatus, as shown in FIG. 2, a moving bed 8 is formed by stacking louvers 8a in a vertically stacked manner so as to cross the duct D, and the moving bed 8 has a particle size of 1c.
A hopper 7 and a rotary valve 7a for supplying CaCO ₃ powder of m or less, and CaC passing through the moving bed 8.
Separation and collection unit 9 for separating and collecting O ₃ powder, and CaCO
It is composed of a CaCO ₃ supply unit 12 that finely pulverizes the CaCO ₃ powder recovered in the ₃ separation and recovery unit 9 and supplies it to the desulfurization device 6 side.
CO ₃ powder is brought into contact with the exhaust gas to remove and recover SO ₃ , and surplus CaCO ₃ powder is supplied as an absorbent on the desulfurization apparatus 6 side.

That is, the smoke exhaust treatment of the smoke exhaust treatment equipment for such an orimulsion-fired boiler will be described in detail. First, as shown in FIG. After the NO _X contained during passage is removed, the combustion air is heated and cooled by the air preheater 3, and then the SO ₃ removal device A of the SO ₃ removal device A is passed through the duct D as shown in FIG. When passing through the moving bed 8, the contained SO ₃ reacts with SO ₃ flowing in the moving bed 8 according to the following chemical formula 1, and is separated from the exhaust gas as CaSO ₄ . At this time, the amount of CaCO ₃ powder supplied from the hopper 7 of the SO ₃ removal device A is set so as to sufficiently react with SO _{3 in} the exhaust gas.

[0012]

## STR00001 ## CaCO ₃ + SO ₃ → CaSO ₄ + CO ₂ This prevents SO ₃ from being released into the atmosphere as it is, and also the dust collector generated when NH ₃ as described above is used. No inconvenience such as corrosion of the heat exchanger 4 and the heat exchanger 5 is eliminated.

As shown in FIG. 1, the exhaust gas from which SO ₃ has been removed in this way has its dust collector 4 removed of soot and then further cooled by a heat exchanger 5 and then desulfurizer 6 Where SO ₃ and SO ₂ are removed and cleaned by contact with the absorbing liquid, and then released into the atmosphere.

On the other hand, as shown in FIG. 2, CaSO ₄ separated from the exhaust gas in the moving bed 8 is unreacted Ca.
The CO ₃ powder is sent to the separation / recovery section 9, where it is further separated and recovered from the CaCO ₃ powder by a sieve (not shown) or the like. That is, since CaSO ₄ sent to the separation / collection unit 9 exists so as to adhere to the surface of the CaCO ₃ powder in a thin film form, CaC 4
The O ₃ powder itself can be easily separated from its surface by sieving. Then, the other CaCO ₃ powder collected by the separation and collection unit 9 is further finely pulverized by the CaCO ₃ supply unit 12, and then, as shown in FIG.
It is sent to the desulfurization device 6 side and dissolved in water to be used as an absorbing liquid. With this, excess CaC
The O ₃ powder can be effectively reused, and the amount of CaCO ₃ used in the desulfurization device can be reduced. At this time, CaC recovered by the separation and recovery unit 9
Part or all of the O ₃ powder may be returned to the hopper 7 side for reuse.

Further, as another embodiment of the SO ₃ removing device A according to the present invention, as shown in FIG.
₃ A nozzle portion 14 for ejecting powder is provided, and the dust collector 4 on the downstream side thereof is provided with the above-described separation / collection portion 9 and CaCO ₃ supply portion 12, and the particle diameter from this nozzle portion 14 is several mm.
The following fine powder is ejected into the duct D to cause SO ₃ in the exhaust gas flowing in the duct D to react with the CaCO ₃ powder to produce CaSO ₄ as the dust collector 4 and the separation / collection unit 9 as described above.
Alternatively, the excess CaCO ₃ powder may be recovered and reused in a desulfurizer.

[0016]

According to the above summary the present invention, since without causing corrosion of the dust collector and heat exchanger, to be effectively removed SO ₃ in combustion exhaust gas of orimulsion out, according to the SO ₃ It is possible to prevent adverse effects of the surrounding environment such as poor visibility.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a preferred embodiment of a flue gas treatment equipment for an orimulsion-fired boiler of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of an SO ₃ removing device according to the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the SO ₃ removal device according to the present invention.

FIG. 4 is a configuration diagram showing an embodiment of a conventional boiler flue gas treatment facility.

[Explanation of symbols]

1 Boiler 2 Denitrification device 4 Dust collector 6 Desulfurization device 8 Moving bed 9 Separation and recovery part 12 CaCO ₃ supply part 14 Nozzle part A SO ₃ removal device D Smoke exhaust duct

Claims (3)

[Claims] 1. A denitration device for removing nitrogen oxides in the combustion exhaust gas of the boiler, and a collector for removing soot and dust in the exhaust gas after denitration, downstream of the boiler that burns orimulsion that generates a large amount of SO _3. Dust container and S in exhaust gas after dust removal
In a flue gas treatment facility for an Orimuljon-fired boiler in which a desulfurization device for removing O ₃ and SO ₂ is connected by a flue gas duct, the exhaust gas passing through this duct is connected to a duct connecting the denitration device and the dust collector. A flue gas treatment equipment for an orimulsion-fired boiler, which is equipped with an SO ₃ removal device for contacting CaCO ₃ to remove SO ₃ in the exhaust gas. 2. The SO ₃ removing device is provided so as to traverse the duct, and CaCO ₃ powder is brought into contact with the combustion exhaust gas passing through the duct to remove SO ₃ from CaS.
A moving bed to remove as O _4, a separation and recovery section for separating and recovering the CaSO ₄ from CaCO ₃ powder having passed through the moving bed, feeding the CaCO ₃ powder separated by the separation collection portion in the desulfurization apparatus A flue gas treatment facility for an orimulsion-fired boiler according to claim 1, further comprising a CaCO ₃ supply unit. 3. The SO ₃ removing device is provided in the duct, and a nozzle portion for ejecting CaCO ₃ fine powder into the duct to remove SO ₃ in the combustion exhaust gas as CaSO ₄ . A separation / collection unit provided in the dust collector for separating and collecting CaSO ₄ from the CaCO ₃ powder collected by the dust collector, and CaC separated by this separation / collection unit
A flue gas treatment facility for an orimulsion-fired boiler according to claim 1, further comprising a CaCO ₃ supply unit for supplying O ₃ powder to the desulfurizer side.