JP2004081975A - Desulfurization method and desulfurization equipment for recovering so2 in gas to be treated as caso4 in coexistence of no and/or no2 - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To separate and recover SO<SB>2</SB>in a gas to be treated as CaSO<SB>4</SB>in a high efficiency. <P>SOLUTION: The gas to be treated is brought into contact with an SO<SB>2</SB>desulfurizing agent, which is obtained by coating the surface of carrier particles having a large particle size with Ca(OH)<SB>2</SB>of fine particles, in a fluidized bed type reaction column 1 by making 10-5,000 ppm NO and/or NO<SB>2</SB>coexist in the SO<SB>2</SB>-containing gas to be treated. The CaSO<SB>4</SB>produced in the column 1 is fluidized in the first gas-solid separator 2 together with the carrier particle and the gas to be treated so that the carrier particle is separated by sedimentation from the gas containing the CaSO<SB>4</SB>produced in the column 1 and exfoliated. The gas containing the CaSO<SB>4</SB>is withdrawn from the upper part of the separator 2 and fed to the second gas-solid separator 3 so that the CaSO<SB>4</SB>is separated and recovered from the gas to be treated by fluidization. <P>COPYRIGHT: (C)2004,JPO

Description

【００１２】
表２に記載のＮＯまたはＮＯ_２を共存（ｐｐｍ）させて脱硫した時と、これらＮＯ_Ｘが共存しなかった時の脱硫特性（％）を表２に示す。ＮＯまたはＮＯ_２の共存効果を比較すると、同じ共存量において、ＮＯ_２の共存効果の方が大きいことが表２から理解される。このことから、ＮＯをＮＯ_２に変換するコンバーターＣＶを設けることが、ＳＯ_２をＣａＳＯ_４として分離回収する脱硫法において顕著な改善をもたらすことは明らかである。またＮＯおよび／またはＮＯ_２の共存量が５０ｐｐｍ〜３００ｐｐｍ以上ではこれらの共存効果はほぼ飽和しており、被処理ガス中に共存すべき最低濃度は１０ｐｍｍであるが上限はない。
【００１３】
【表２】

【００１４】
実施例２
ＮＯ、ＮＯ_２の共存量がそれぞれ４８０ｐｐｍにおける脱硫率（Ｃａ／Ｓ）の効果を実験した結果を表３に示す。
前記実験を、被処理ガスとして、ＳＯ_２含有量が１５００ｐｐｍ、ＣＯ_２含有量が１２％、Ｏ_２含有量が８％のを試料を、脱硫剤として、実施例１で用いたものと同じ化学組成、平均粒径および表面積を持つフライアッシュを用い、これに、のＣａ（ＯＨ）_２を（キャリヤー粒子＋Ｃａ（ＯＨ）_２）との重量比が１．５になるように被覆したものを用いて、実施した。表３の結果から、脱硫率に対するＮＯおよびＮＯ_２の共存の効果が明らかであり、ＮＯ_２の共存による脱硫率の向上への効果は、ＮＯの共存による脱硫率の向上への効果に比べて安定していることも分かった。このことは、ＮＯ_２の共存は脱硫反応の安定した反応に効果があることが理解される。
【００１５】
【表３】

【００１６】
実施例３
ここでは、大粒径のキャリヤー粒子表面に微粒子のＣａ（ＯＨ）_２を被覆したＳＯ_２脱硫剤を用いた場合における、キャリヤー粒子表面の微粒子のＣａ（ＯＨ）_２とＳＯ_２との反応により形成されたＣａＳＯ_４をキャリヤー粒子表面から脱離する特性に対するＮＯ（４８０ｐｐｍ）およびＮＯ_２（４８０ｐｐｍ）の共存効果を、粒子飛沫量の経時変化として表４と図２に示す。
【００１７】
【表４】

【００１８】
粒子飛沫量＝（飛沫した粒子のうちのＣａの量ｇ／分）÷（供給した脱硫剤のＣａ量ｇ／分）である。ＮＯ（□）およびＮＯ_２（▲）の添加により、飛沫粒子が増えている〔ＮＯもＮＯ_２も共存しない場合は（◆）で示した。〕。このことはＮＯもＮＯ_２の共存により脱硫剤が有効にはたらき、効率よく石膏が得られていることを意味する。ＮＯの場合は、経時と飛沫量の関係を示す上記結果を見ると、変動が大きく、飛沫量が安定していない、換言すれば安定な反応が進行していなく、制御性あまり良くない。これに対して、ＮＯ_２の共存の場合には飛沫量が非常に安定している。このことから、ＮＯ_２の共存下でＳＯ_２含有被処理ガス中のＳＯ_２をＣａＳＯ_４として分離回収する脱硫法がより効果的であることが理解される。
【００１９】
【発明の効果】
以上述べたように、本発明は、ＳＯ_２を含む被処理ガスにＮＯおよび／またはＮＯ_２を１０〜５０００ｐｐｍ共存させ、大粒径のキャリヤー粒子表面に微粒子のＣａ（ＯＨ）_２を被覆したＳＯ_２脱硫剤と接触させてＳＯ_２をＣａＳＯ_４として分離回収する脱硫方法を確立し、ＳＯ_２を高効率で有用な副生物であるＣａＳＯ_４として回収可能にし、実用的な環境改善手段を供給した点で、社会に貢献すること多大であることは明らかである。
【図面の簡単な説明】
【図１】本発明の脱硫装置の概念図
【図２】ＳＯ_２含有被処理ガス中へのＮＯおよびＮＯ_２の共存のＳＯ_２をＣａＳＯ_４として分離回収特性と粒子飛沫の量の経時変化の相関
【符号の説明】
１　流動層形成反応塔　２　第１の気体−固体分離器　３　第２の気体−固体分離器
４　被処理ガス吹き込み部　５　分離キャリヤー粒子の還流管
６　ＣａＳＯ_４を含む気体の移送管　７　処理済み被処理ガス
８　回収ＣａＳＯ_４を含む固体反応物取り出し配管
９　ＳＯ_２脱硫剤供給部（ＳＯ_２脱硫剤製造・供給装置）
ＣＶ　ＮＯ_２コンバーター　ＯＤ　酸化剤供給手段
Ｂ　ボイラー（被処理ガス発生源）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a desulfurization method for separating and recovering a gas to be treated, for example, SO ₂ in an exhaust gas as CaSO ₄ , and a desulfurization method and a desulfurization device for the gas to be treated, wherein the recovery rate of CaSO _{4 in} a desulfurization device is improved. The present invention relates to a desulfurization method and a desulfurization apparatus for separating and recovering SO ₂ in a gas to be treated as CaSO ₄ , wherein at least 10 ppm, and preferably 100 ppm of NO and / or NO ₂ coexist therein.
[0002]
[Prior art]
SO ₂ is a substance that has a significant impact on the environment and human health, and SO ₂ generated from the coal combustion process is a major social problem. Therefore, systems for absorbing and removing SO ₂ have been studied. One of them is an absorption removal method using CaO. The absorption and removal of SO ₂ using CaO is performed through a process of diffusion of SO ₂ and formation of CaSO ₄ / CaSO ₃ by a solid-state reaction. Therefore, the characteristics of the CaO particles, that is, the surface area, pore diameter, pore volume, etc., have a great influence on the adsorption reaction. Commercially available CaO does not have a good calcium utilization factor in terms of SO ₂ absorption and removal properties.
[0003]
Sanders et al. (Sanders et al.) Have reported that the use of a mixed slurry of fly ash and slaked lime improves the SO ₂ absorption and removal characteristics (Sanders et al., Ind. Eng. Chem.). Res. 1995, 34 (4), 302-307). In that report, the improvement in the absorption and removal characteristics of SO ₂ is due to the presence of calcium silicate hydrate formed by the hydration reaction between calcium and alumina silicate, and the difference in reactivity is due to the structure of calcium silicate hydrate. It is explained that there is. In addition, a γ-alumina-CaO adsorbent (Svoboda et al.), A slurry from CaO, calcium sulfate, and fly ash are aged at about 100 ° C., and then dried to obtain an adsorbent (Hiroaki et al.). (It is considered that ettringate is formed. A similar technique is disclosed in Japanese Patent Publication No. 3-59737). However, a method for preparing these adsorbents is water. Relatively high usage, poor availability in poorly watered areas, and long and / or high energy requirements to remove water, and adsorption during preparation of SO ₂ adsorbent forming a composition for improving the properties since such management process is difficult, to design an apparatus of the desulfurization apparatus so as to direct the production apparatus of the sO ₂ sorbent to the desulfurization apparatus There is a disadvantage that Shii.
[0004]
On the other hand, the present inventors know the mechanism of the hydration process in the process of mixing CaO and fly ash in water to prepare an adsorbent, so that the activity from the raw material to a more practical process can be obtained. The research for producing a desulfurizing agent having excellent SO ₂ adsorption characteristics has been intensively conducted (Energy & Fuels, Vol. 13, No. 5, 1015-1020, 1999. Reference A). However, here, the amount of water used to prepare the desulfurizing agent is such that the weight ratio of H ₂ O / (carrier particles + Ca (OH) ₂ ) is relatively high, such as 1.5. The conditions of water use still need improvement in areas where water resources are scarce, for use as desulfurization methods. Further, at that time, in order to minimize waste, it is important to improve the utilization of by-products and the utilization efficiency of the added desulfurizing agent. Therefore, the present inventors have further advanced the above-mentioned technology and studied a desulfurizing agent which can design a dry desulfurization process at a practical level, and found that Ca (OH) which has a relatively large particle size and is an absorption desulfurization component of SO ₂ is used. _The use of carrier particles capable of coating the surface with Ca ₂ improves the utilization rate of Ca of Ca (OH) ₂ , which is an absorption and desulfurization component of SO ₂ , and uses CaSO ₄ efficiently and highly as a by-product. A desulfurization method and a desulfurization device invention capable of separation and recovery have been completed and disclosed (Japanese Patent Application Laid-Open No. 2002-113326). Further, the present inventors in [Fuel, 78 / 9,1089-1095 (1999)], but has published the effect of chain reaction of the NO _x present in the gas in the desulfurization process, the carrier particles with a large particle size The effect on the recovery rate of CaSO ₄ in the desulfurization method of separating and recovering SO ₂ in the gas to be treated as CaSO ₄ using an SO ₂ desulfurizing agent coated on the surface with fine particle Ca (OH) ₂ has been completely studied. Not.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a desulfurization method and a desulfurization method capable of recovering CaSO ₄ as a useful by-product at a higher rate by using a SO ₂ desulfurizing agent in which fine-particle Ca (OH) ₂ is coated on the surface of a large-sized carrier particle. It is to provide a device. In the desulfurization method and the desulfurization apparatus using the desulfurizing agent, CaSO ₄ generated by reacting with SO ₂ in the month to be treated on the surface of the large-size carrier particles coated with Ca (OH) ₂ is efficiently converted from the carrier surface. Good exfoliation is important for recovering CaSO ₄ at a higher rate.
It was not clear what factors were involved in the improvement of the stripping efficiency. However, in order to improve the desulfurization method using the desulfurizing agent, NO _x (X 1) 2) Focusing on the coexistence effect, when NO and / or NO ₂ coexisted, it was found that the recovery characteristics of CaSO ₄ were improved, and the above problem could be solved.
[0006]
[Means for Solving the Problems]
The first invention is a desulfurization process of separating and recovering a SO ₂ in the treated gas with 10~5000ppm coexist NO and / or NO ₂ in the exhaust gas as CaSO _4. Preferably, the NO and / or NO ₂ in the treated gas containing SO ₂ is 10~5000ppm coexist, said SO ₂ desulfurizing agent coated with particles of Ca _{(OH) 2} to the carrier particle surface of the large particle size SO ₂ In a reaction tower in a state where a fluidized bed is formed with the gas to be treated, and while the desulfurizing agent reacts with SO ₂ , the reaction gas is raised in the reaction tower together with the gas to be treated, and from the top of the reaction tower, CaSO ₄ formed by the reaction between the SO ₂ and the fine particles of Ca (OH) ₂ on the surface of the carrier particles flows to the first gas-solid separator together with the carrier particles and the gas to be treated, and the first gas - in the gas containing CaSO ₄ it was formed, removed by reaction with Ca (OH) ₂ and SO ₂ of the carrier particles surface with the solid separator in precipitated the carrier particles Release, the gas containing the CaSO ₄ wherein the first gas - to flow to the solid separator, a second gas - - from the solid separator upper second gas separation the CaSO ₄ from the gas to be treated in the solid separator A desulfurization method for separating and recovering SO ₂ in the gas to be treated as CaSO ₄ , which is characterized in that the gas to be treated is more preferably recovered by coexisting ₁₀ to 5000 ppm of NO and / or NO ₂ in the gas to be treated. When the desulfurization method for separating and recovering SO ₂ in the gas to be treated as CaSO ₄ does not contain NO and / or NO _{2 in} the exhaust gas, or if it is insufficient, NO and / or NO characterized in that said supplying ₂ SO ₂ in the treated gas are desulfurization process of separating and recovering as CaSO _4, more preferably, is NO ₂ in the gas to be treated contains Not have to, desulfurization process for separating and recovering a SO ₂ in the treated gas coexist least NO ₂ as CaSO ₄ is, when NO is present in the gas to be treated, at least the NO of the treated gas part by way of the processing means for converting to nO _2, also when the nO and nO ₂ is not present to supply nO to the front of the processing means for converting at least a portion of nO to nO ₂ or, nO ₂ Is supplied into the processing gas from the outside, and then the gas to be processed is supplied to the reaction tower in which the SO ₂ desulfurizing agent in which the fine particles of Ca (OH) ₂ are coated on the surface of the large-sized carrier particles is present. This is a desulfurization method in which SO ₂ in each of the gases to be treated is separated and recovered as CaSO ₄ , and more preferably, the treatment means for converting at least a part of NO into NO ₂ is at 300 ° C. to 400 ° C. Gas to be oxidized by atomizing and injecting tanol and t-butyl peroxide into the gas to be processed via a processing means for converting at least a part of NO in the gas to be processed to NO ₂ the SO ₂ in a desulfurization method of separating and recovering as CaSO _4.
[0007]
The second aspect of the present invention is a reaction column 1 in which an SO ₂ desulfurizing agent in which fine particles of Ca (OH) ₂ are coated on the surface of carrier particles having a large particle diameter forms a fluidized bed by supplying a gas to be treated. A desulfurizing agent supply device for supplying a SO ₂ desulfurizing agent in which fine particles of Ca (OH) ₂ are coated on the surface of carrier particles having a particle size, a device for causing NO and / or NO ₂ to coexist in a gas to be treated containing SO ₂ , A gas blowing device for blowing a gas to be treated containing SO _{2 in} which NO and / or NO ₂ coexists, wherein the desulfurizing agent is brought into contact with the gas to be treated containing SO ₂ in a reaction tower in a state of forming a fluidized bed. Then, the desulfurizing agent and SO ₂ are reacted with each other to rise in the reaction tower together with the gas to be treated, and from the upper part of the reaction tower, the SO ₂ reacts with the fine particles of Ca (OH) ₂ on the surface of the carrier particles. By shape Insufflated CaSO ₄ that are together with the carrier particles and the gas to be treated, the gas to be treated containing the CaSO ₄ to the carrier particles detached are formed, at the surface of the carrier first separating by settling the carrier particles A gas to be treated containing the CaSO ₄ is blown from the gas-solid separator and the first gas-solid separator, and a second gas-solid separator that separates the CaSO ₄ from the blown gas to be treated. This is a desulfurization apparatus that separates and recovers SO ₂ in a gas to be treated as CaSO ₄ , which is characterized by having the same. Preferably, the apparatus for causing NO and / or NO ₂ to coexist in the gas to be treated containing SO ₂ is disposed before supplying the gas to be treated for separating and recovering SO ₂ as CaSO ₄ to the reaction tower forming the fluidized bed. it is, wherein the is intended to include a converter for converting the NO and / or device for supplying NO and / or NO ₂ from the outside to the NO ₂ to 10~5000ppm and / or NO in the gas to be treated to NO ₂ A desulfurization apparatus for separating and recovering SO ₂ in the gas to be treated as CaSO ₄ , and more preferably sediments and separates the carrier particles from the gas to be treated including CaSO ₄ and a reaction tower 1 forming a fluidized bed. first gas - solid separator and that forms a circulating fluidized layer and CaSO ₄ the SO ₂ in the treated gas, wherein in A desulfurization apparatus for separating and recovering Te.
[0008]
[Embodiment of the present invention]
The present invention will be described in more detail.
A. FIG. 1 shows SO ₂ desulfurization in which 10 to 5000 ppm of NO and / or NO ₂ coexist in a gas to be treated containing SO _{2 according} to the present invention, and fine Ca (OH) ₂ is coated on the surface of large-size carrier particles. FIG. 2 is a conceptual diagram of a desulfurization apparatus for bringing an agent into contact with a gas to be treated containing SO ₂ in a reaction tower in a state of forming a fluidized bed to separate and recover SO ₂ in the gas to be treated as CaSO ₄ . 1 is a fluidized bed formation reaction tower provided with a perforated plate (PP). An apparatus for supplying a gas to be treated in which 10 to 5000 ppm of NO and / or NO ₂ coexists in the gas to be treated (gas to be treated) from the boiler B, for example, below the porous plate PP of the reaction tower 1; For example, a blower pump is connected. To NO and / or NO ₂ coexist in the gas to be treated, at least of NO coexisted the device for supplying NO and / or NO ₂ in front of the device for supplying a gas to be treated, and / or to be treated in the gas A device CV for converting a part to NO ₂ and an OD for blowing an oxidizing agent for promoting the conversion are provided.
[0009]
Above the perforated plate PP, an SO ₂ desulfurizing agent supply device 9, here, a desulfurizing agent manufacturing device, is directly connected to the reaction tower 1. The desulfurizing agent and devices after the reaction tower are described in detail in the above-mentioned Japanese Patent Application Laid-Open No. 2002-113326, which has already been proposed by the present inventors. The technical description described in the above-mentioned publication describes that a SO ₂ desulfurizing agent in which fine particles of Ca (OH) ₂ are coated on the surface of large-sized carrier particles is mixed with a gas to be treated containing SO ₂ to form a fluidized bed. In the desulfurization method and desulfurization apparatus for separating and recovering SO ₂ in the gas to be treated as CaSO ₄ by contacting inside the gas to be treated, except for the technical feature of the present invention of “coexisting NO and / or NO _{2 in the} gas to be treated”, It should be understood that they are closely related to the present invention and form a part of the technical description of the present invention.
[0010]
【Example】
The description herein is only for facilitating the understanding of the present invention, and does not limit the present invention.
Example 1
As the gas to be treated, a sample having an SO ₂ content of 1500 ppm, a CO ₂ content of 12%, and an O ₂ content of 8% was used as a sample. As the desulfurizing agent, as the carrier particles, fly ash having the chemical composition shown in Table 1 below, having an average particle size of 137 μm, and a surface area of 126 m ² / g was used, and Ca (OH) ₂ was added to the (carrier particles + Ca). (OH) ₂ ) was used so as to have a weight ratio of 1.5. This was supplied so that the Ca / S ratio became 1.7, the gas superficial velocity was 0.75 m / s, the temperature of the reactor (circulating fluidized bed forming reaction tower) was 350 ° C., and the gas phase residence time was 1. 5 seconds (s) and a pressure loss of 1 kPa (corresponding to the desulfurizing agent particle filling rate).
[0011]
[Table 1]

[0012]
And when desulfurization of NO or NO ₂ coexist (ppm) shown in Table 2, the desulfurization characteristics when these NO _X does not coexist (%) shown in Table 2. Comparing the coexistence effect of NO or NO _2, in the same coexistence amount, it is understood from Table 2 towards the coexistence effect of NO ₂ is large. From this, it is clear that providing a converter CV for converting NO to NO ₂ provides a remarkable improvement in a desulfurization method for separating and recovering SO ₂ as CaSO ₄ . Also these coexistence effect in amount coexistence more 50ppm~300ppm of NO and / or NO ₂ is almost saturated, the lowest concentration should coexist in the gas to be treated is a 10pmm no upper limit.
[0013]
[Table 2]

[0014]
Example 2
Table 3 shows the results of experiments on the effect of the desulfurization rate (Ca / S) when the coexistence amounts of NO and NO ₂ were 480 ppm, respectively.
In the above experiment, the same chemical as that used in Example 1 was used as a desulfurizing agent, using a sample having a SO ₂ content of 1500 ppm, a CO ₂ content of 12%, and an O ₂ content of 8% as a gas to be treated. composition, using fly ash having an average particle size and surface area, with which this weight ratio of Ca to _{(OH) 2} and (carrier particles + Ca _{(OH) 2)} of coated so that 1.5 And implemented. From the results in Table 3, the effect of the coexistence of NO and NO _{2 on} the desulfurization rate is clear, and the effect of the coexistence of NO _{2 on} the improvement of the desulfurization rate is greater than the effect of the coexistence of NO on the improvement of the desulfurization rate. It turned out to be stable. This indicates that the coexistence of NO ₂ is effective for a stable desulfurization reaction.
[0015]
[Table 3]

[0016]
Example 3
Here, formed by reaction of in the case of using the SO ₂ desulfurizing agent coated with particles of Ca _{(OH) 2} to the carrier particle surface with a large grain size, and Ca _{(OH) 2} and SO ₂ of the fine particles of the carrier particles surface Table 4 and FIG. 2 show the effect of coexistence of NO (480 ppm) and NO ₂ (480 ppm) on the characteristics of desorbing CaSO ₄ from the surface of the carrier particles, as a change with time of the amount of particles splashed.
[0017]
[Table 4]

[0018]
Particle droplet amount = (Ca amount g / min in droplets) / (Ca amount g / min of supplied desulfurizing agent). The addition of NO (□) and NO ₂ (▲) resulted in an increase in the number of droplets. (If neither NO nor NO ₂ coexist, this is indicated by (◆). ]. This is NO desulfurization agent effectively works by coexistence of NO _2, which means that efficient gypsum is obtained. In the case of NO, the above results showing the relationship between time and the amount of droplets show that the variation is large, the amount of droplets is not stable, in other words, a stable reaction does not progress, and the controllability is not very good. On the other hand, in the case of coexistence of NO _2, the amount of droplets is very stable. Therefore, it is understood desulfurization method of separating and recovering SO ₂ of SO ₂ containing treated gas as CaSO ₄ in the presence of NO ₂ is more effective.
[0019]
【The invention's effect】
As described above, the present invention relates to an SO in which NO and / or NO ₂ is present in the gas to be treated containing SO ₂ in an amount of ₁₀ to 5000 ppm, and the surface of large-size carrier particles is coated with fine Ca (OH) _{2. (2)} Established a desulfurization method for separating and recovering SO ₂ as CaSO ₄ by contacting it with a desulfurizing agent, enabling SO ₂ to be recovered as CaSO ₄ , which is a highly efficient and useful by-product, and supplying practical environmental improvement means. In this respect, it is clear that contributing to society is great.
[Brief description of the drawings]
[1] of the desulfurization apparatus of the present invention conceptual diagram [2] SO ₂ content of the separation and recovery characteristics and particle splash the SO ₂ coexistence of NO and NO ₂ to be treated in the gas as CaSO ₄ the amount of change over time Correlation [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fluidized bed formation reaction tower 2 1st gas-solid separator 3 2nd gas-solid separator 4 Gas injection part 5 Reflux pipe of separation carrier particles 6 Transfer pipe of gas containing CaSO ₄ 7 Treated pipe Processing gas 8 Solid reactant removal pipe containing recovered CaSO ₄ 9 SO ₂ desulfurizing agent supply unit (SO ₂ desulfurizing agent production / supply device)
CV NO ₂ converter OD Oxidant supply means B Boiler (source of gas to be treated)

Claims (8)

A desulfurization method in which 10 to 5000 ppm of NO and / or NO ₂ coexist in a gas to be treated and SO ₂ in the gas to be treated is separated and recovered as CaSO ₄ . NO and / or NO ₂ is present in the gas to be treated containing SO ₂ in an amount of ₁₀ to 5000 ppm, and the SO ₂ desulfurizing agent in which fine particles of Ca (OH) ₂ are coated on the surface of large-size carrier particles is treated with the SO ₂ containing SO _2. process gas is contacted in a reaction column at a state of forming a fluidized bed, wherein while reacting the desulfurizing agent and SO ₂ increased the reaction column together with the gas to be treated, from said top of said reactor SO ₂ and the carrier particles the surface of the microparticle Ca (OH) ₂ and the first gas to CaSO ₄ formed by the reaction together with the carrier particles and the treated gas - to flow to the solid separator, said first gas - solid separation separated from gas containing CaSO ₄ was formed, removed by reaction with Ca (OH) ₂ and SO ₂ in the carrier particle surfaces in a vessel and allowed to settle the carrier particles, the C Wherein the gas containing SO ₄ first gas - solid separator top from the second gas - to flow to the solid separator, a second gas - the CaSO ₄ to separate and recover from the gas to be treated in the solid separator desulfurization process for separating and recovering a SO ₂ in the treated gas according as CaSO ₄ in claim 1, characterized in that. The desulfurization method for separating and recovering SO ₂ in the gas to be treated as CaSO ₄ by coexisting ₁₀ to 5000 ppm of NO and / or NO ₂ in the gas to be treated does not include NO and / or NO _{2 in the} exhaust gas. _3. Desulfurization for separating and recovering SO ₂ in a gas to be treated as CaSO _{4 according} to claim 1 or 2, wherein NO and / or NO ₂ is supplied from the outside when the content is insufficient. Method. Not include a NO ₂ in the gas to be treated, desulfurization process for separating and recovering a SO ₂ in the treated gas coexist least NO ₂ as CaSO ₄ is, when NO is present in the gas to be treated , pre-processing means for converting at least a portion of nO in the treated gas by way of the processing means for converting to nO _2, also when the nO and nO ₂ is not present at least a portion of nO to nO ₂ After the supply of NO or the supply of NO ₂ from the outside into the processing gas, the gas to be processed is reacted with a SO ₂ desulfurizing agent in which fine particles of Ca (OH) ₂ are coated on the surface of large-sized carrier particles. desulfurization process for separating and recovering a SO ₂ as CaSO ₄ of the treated gas according to claim 1 or 2, characterized in that fed to the column. Methanol in at least processing means for converting part of the NO ₂ is 300 ° C. to 400 ° C. NO, the according to claim 4, characterized in that the oxidation by atomizing press-t- butyl peroxide A desulfurization method for separating and recovering SO ₂ in a gas to be treated as CaSO ₄ . A reaction tower 1 in which a SO ₂ desulfurizing agent in which fine particles of Ca (OH) ₂ are coated on the surface of large-size carrier particles forms a fluidized bed by supplying a gas to be treated. A desulfurizing agent supply device for supplying an SO ₂ desulfurizing agent coated with fine particle Ca (OH) ₂ , a device for allowing NO and / or NO ₂ to coexist in a gas to be treated containing SO ₂ , NO and / or NO ₂ A gas-to-be-processed gas blowing device for blowing a gas to be treated containing SO ₂ coexisting, the desulfurizing agent is brought into contact with the gas to be treated containing SO ₂ in a reaction tower in a state of forming a fluidized bed, and the desulfurizing agent and SO ₂ Is raised in the reaction tower together with the gas to be treated, and CaSO ₄ formed by the reaction between the SO ₂ and the fine particles of Ca (OH) ₂ on the surface of the carrier particles from above the reaction tower. Is blown together with the carrier particles and the gas to be treated, and the carrier particles are settled and separated from the gas to be treated containing CaSO ₄ formed and desorbed on the surface of the carrier by first settling. A gas-to-be-processed gas containing the CaSO ₄ is blown from the vessel and the first gas-solid separator, and a second gas-solid separator for separating the CaSO ₄ from the blown gas-to-be-processed is provided. A desulfurization apparatus for separating and recovering SO ₂ in the gas to be treated as CaSO ₄ . An apparatus for allowing NO and / or NO ₂ to coexist in the gas to be treated containing SO ₂ before the gas to be treated for separating and recovering SO ₂ as CaSO ₄ is supplied to a reaction tower for forming a fluidized bed; claim, characterized in that it comprises a converter for converting the device and / or NO supplying NO and / or NO ₂ from the outside to the NO and / or NO ₂ in the treated gas to 10~5000ppm to NO ₂ 6 _3. A desulfurization apparatus for separating and recovering SO ₂ in a gas to be treated as CaSO ₄ . A circulating fluidized bed is formed by the reaction column 1 forming a fluidized bed and the first gas-solid separator for sedimenting and separating the carrier particles from the gas to be treated containing CaSO _4. A desulfurization apparatus for separating and recovering SO ₂ in a gas to be treated according to claim 6 or 7 as CaSO ₄ .

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