JP5275064B2 - Exhaust gas treatment apparatus and method for oxyfuel coal fired boiler - Google Patents

Exhaust gas treatment apparatus and method for oxyfuel coal fired boiler Download PDF

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JP5275064B2
JP5275064B2 JP2009021630A JP2009021630A JP5275064B2 JP 5275064 B2 JP5275064 B2 JP 5275064B2 JP 2009021630 A JP2009021630 A JP 2009021630A JP 2009021630 A JP2009021630 A JP 2009021630A JP 5275064 B2 JP5275064 B2 JP 5275064B2
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exhaust gas
boiler
desulfurization
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典幸 今田
郷紀 佐々木
直己 尾田
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バブコック日立株式会社
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Description

本発明は、石炭焚ボイラの排ガス中に含まれるSO2を除去する排ガス処理装置に係わり、特に酸素燃焼用石炭焚ボイラの排ガス処理装置と方法に関するものである。 The present invention relates to an exhaust gas treatment apparatus for removing SO 2 contained in the exhaust gas of a coal fired boiler, and more particularly to an exhaust gas treatment apparatus and method for an oxygen fired coal fired boiler.
近年、地球温暖化の原因の一つと言われている二酸化炭素(CO2)の排出量を低減する技術の一つとして、酸素燃焼方式のボイラが注目されている。この酸素燃焼方式は、酸化剤として空気の代わりに酸素を使用することで、CO2を主成分とする排ガスを発生させて、直接CO2の圧縮、回収を行うものである。石炭を燃料とした場合の酸素燃焼型ボイラの一例を図6に示す。 In recent years, oxyfuel boilers have attracted attention as one of the techniques for reducing carbon dioxide (CO 2 ) emission, which is one of the causes of global warming. In this oxyfuel combustion method, oxygen is used in place of air as an oxidant to generate exhaust gas mainly composed of CO 2 to directly compress and recover CO 2 . An example of an oxyfuel boiler using coal as fuel is shown in FIG.
図6においてボイラ1で石炭21と酸素22を燃焼させ、発生した熱により蒸気を発生させる。燃焼排ガスは、後流に設置した脱硝装置2で窒素酸化物(NOx)が低減され、ついて空気加熱機(A/H)3で温度が低下された後、集塵機4で灰が除去され、脱硫装置5で硫黄酸化物(SOx)が除去された後、CO2圧縮機6でCO2を圧縮、回収する構成となっている。 In FIG. 6, coal 21 and oxygen 22 are burned in the boiler 1, and steam is generated by the generated heat. The combustion exhaust gas is reduced in nitrogen oxide (NOx) by a denitration device 2 installed in the downstream, and after the temperature is lowered by an air heater (A / H) 3, ash is removed by a dust collector 4 and desulfurized. After the sulfur oxide (SOx) is removed by the apparatus 5, the CO 2 compressor 6 compresses and collects CO 2 .
石炭を酸素で燃焼させる場合、燃焼温度が非常に高温となるために、ガス温度を下げる必要がある。そのため、一般的には排ガスの一部をボイラ1に循環させ、酸素と混合して使用する方法が用いられる。図6には、その一例として、脱硫装置5の後流に排ガスをボイラ1に循環する排ガス循環ライン8と循環用ファン9を設置した例を示している。排ガスは、ボイラ1の燃料及び酸素供給部に接続する構成となっている。排ガス循環量は、従来の空気燃焼時とガス温度が同じになるように設定することが一般的であり、その量は排ガス量全体の7〜8割である。 When coal is burned with oxygen, the combustion temperature becomes very high, so it is necessary to lower the gas temperature. Therefore, generally, a method is used in which a part of the exhaust gas is circulated through the boiler 1 and mixed with oxygen. FIG. 6 shows an example in which an exhaust gas circulation line 8 for circulating exhaust gas to the boiler 1 and a circulation fan 9 are installed in the downstream of the desulfurization apparatus 5 as an example. The exhaust gas is connected to the fuel and oxygen supply section of the boiler 1. The exhaust gas circulation amount is generally set so that the gas temperature is the same as in conventional air combustion, and the amount is 70 to 80% of the entire exhaust gas amount.
特開2007−147162号公報JP 2007-147162 A
前記従来技術においては、脱硫装置の性能低下について考慮されておらず、空気燃焼時と同等のSO2除去性能を得るためには、脱硫装置が大きくなるという問題があった。 In the prior art, the performance degradation of the desulfurization apparatus is not taken into consideration, and there is a problem that the desulfurization apparatus becomes large in order to obtain SO 2 removal performance equivalent to that during air combustion.
空気燃焼時と酸素燃焼時における排ガス組成の違いは、酸化剤として酸素を使うために排ガスの主成分がCO2になる他に、水分濃度が高くなるという違いがある。表1に、石炭を燃焼した場合の空気燃焼、酸素燃焼時における排ガス組成の例を示す。空気燃焼時では、排ガスの主成分はN2であり、水分濃度は11%である。これに対し、酸素燃焼時では排ガスの主成分はCO2であり、水分濃度は32%と高くなることが分かる。 The difference in exhaust gas composition between air combustion and oxygen combustion is that the main component of the exhaust gas is CO 2 in order to use oxygen as an oxidant, and the moisture concentration is high. Table 1 shows examples of exhaust gas composition during air combustion and oxyfuel combustion when coal is burned. At the time of air combustion, the main component of the exhaust gas is N 2 and the moisture concentration is 11%. In contrast, during oxyfuel combustion, the main component of the exhaust gas is CO 2 , and the moisture concentration is as high as 32%.
排ガス中の水分濃度が高くなることで、脱硫装置のSO2除去性能が低下するという問題がある。図3及び図4に排ガス中の水分濃度とSO2除去特性との関係を示す。排ガス中の水分濃度が高くなるとSO2除去特性が低下することが分かる。これは、排ガス中の水分濃度が高くなることで、脱硫塔内のガス温度や脱硫吸収液の温度が高くなり、脱硫吸収液へのSO2の溶解度が低下することが原因と考えられる。 There is a problem that the SO 2 removal performance of the desulfurization apparatus is lowered due to the high water concentration in the exhaust gas. 3 and 4 show the relationship between the moisture concentration in the exhaust gas and the SO 2 removal characteristics. It can be seen that the SO 2 removal characteristics decrease as the moisture concentration in the exhaust gas increases. This is presumably because the gas concentration in the desulfurization tower and the temperature of the desulfurization absorbent increase due to the high water concentration in the exhaust gas, and the solubility of SO 2 in the desulfurization absorbent decreases.
そのため、空気燃焼時と同等のSO2除去性能を得るためには、吸収塔に循環する脱硫吸収液の量を増加したり、脱硫吸収液と排ガスとの接触時間を長くする必要があるため、脱硫装置が大きくなるという問題があった。 Therefore, in order to obtain SO 2 removal performance equivalent to that at the time of air combustion, it is necessary to increase the amount of the desulfurization absorbent circulating in the absorption tower or to increase the contact time between the desulfurization absorbent and the exhaust gas. There was a problem that the desulfurization apparatus became large.
本発明の課題は、酸素燃焼排ガスのように水分濃度が高い場合においても、脱硫装置の大きさを変えることなく、空気燃焼時と同等のSO2除去率を達成すること可能にし、ボイラ水を節約して水の省資源化を図ることである。 An object of the present invention, when the moisture concentration as the oxygen combustion exhaust gas is higher, without changing the size of the desulfurization apparatus, possible to achieve a time air combustion equivalent SO 2 removal rate, boiler water Saving water and saving water resources .
本発明の上記課題は、次の構成により解決される。
すなわち、請求項1記載の発明は、石炭を酸素を酸化剤として燃焼させて蒸気を発生するボイラと、該ボイラからの排ガス中の窒素酸化物を除去する脱硝装置と、排ガス中の硫黄酸化物を吸収液を排ガス中に噴霧することで除去する湿式排煙脱硫装置と、該湿式排煙脱硫装置内の吸収液の冷却をする吸収液冷却装置と、湿式排煙脱硫装置の前流側又は後流側の排ガスの一部をボイラ燃焼部に循環する排ガス循環ラインとを備えた酸素燃焼用石炭焚ボイラの排ガス処理装置において、ボイラで生成した蒸気を蒸気利用機器で使用した後に復水させる復水器を設け、該復水器出口のボイラ水を、前記湿式排煙脱硫装置内の貯留吸収液冷却用の吸収液冷却装置を経由してボイラに再循環する冷却水流路を配置した酸素燃焼用石炭焚ボイラの排ガス処理装置である。
The above-described problems of the present invention are solved by the following configuration.
That is, the invention according to claim 1 is a boiler that generates steam by burning coal using oxygen as an oxidizing agent, a denitration device that removes nitrogen oxides in the exhaust gas from the boiler, and a sulfur oxide in the exhaust gas. a wet flue gas desulfurization apparatus of the absorption liquid is removed by spraying into the exhaust gas, and absorbing liquid cooling device for cooling the absorbent liquid in the wet type exhaust gas desulfurization apparatus, the upstream side of the wet flue gas desulfurization system or In an exhaust gas treatment system for an oxyfuel coal-fired boiler equipped with an exhaust gas circulation line that circulates part of the exhaust gas on the downstream side to the boiler combustion section, the steam generated in the boiler is condensed after being used in the steam utilization equipment. Oxygen provided with a condenser and disposed with a cooling water flow path for recirculating the boiler water at the outlet of the condenser to the boiler via the absorption liquid cooling apparatus for cooling the stored absorption liquid in the wet flue gas desulfurization apparatus Exhaust gas treatment facility for combustion coal fired boiler It is a device.
請求項2記載の発明は、石炭を酸素を酸化剤として燃焼させて蒸気を発生するボイラからの排ガス中の窒素酸化物を脱硝装置で除去し、湿式排煙脱硫装置で排ガス中の硫黄酸化物を吸収液を排ガス中に噴霧することで除去し、湿式排煙脱硫装置の前流側又は後流側の排ガスの一部をボイラ燃焼部に循環し、湿式排煙脱硫装置内の吸収液を冷却して50℃以下にする酸素燃焼用石炭焚ボイラの排ガス処理方法において、ボイラで生成した蒸気を蒸気利用機器で使用した後に復水させる復水器出口のボイラ水を湿式排煙脱硫装置内の吸収液中に導き、吸収液を冷却して50℃以下にする酸素燃焼用石炭焚ボイラの排ガス処理方法である。 The invention according to claim 2 removes nitrogen oxides in exhaust gas from a boiler that generates steam by burning coal using oxygen as an oxidant, and removes sulfur oxides in the exhaust gas with a wet flue gas desulfurization device . Is removed by spraying the absorption liquid into the exhaust gas, and a part of the exhaust gas on the upstream side or the downstream side of the wet flue gas desulfurization apparatus is circulated to the boiler combustion section to absorb the absorption liquid in the wet flue gas desulfurization apparatus. In an exhaust gas treatment method for an oxyfuel coal fired boiler that is cooled to 50 ° C. or lower, the boiler water at the condenser outlet that condenses the steam generated in the boiler after being used in the steam-utilizing equipment in the wet flue gas desulfurization apparatus This is an exhaust gas treatment method for a coal fired boiler for oxyfuel combustion , which is introduced into the absorbent and cooled to 50 ° C. or lower .
(作用)
排ガス中に含まれる水分濃度の増加による脱硫装置のSO2除去性能の低下は、水分濃度の増加による脱硫装置内の温度上昇が主原因である。湿式脱硫装置の構造を図2に示すが、入口ダクトより約160℃の排ガスが供給され、脱硫塔上部より脱硫吸収液を噴霧することで、排ガス中に含まれるSO2を脱硫吸収液により吸収、除去している。
このとき、脱硫吸収液の一部は蒸発し、その蒸発潜熱によって排ガスの温度が低下する。脱硫吸収液の蒸発量は、水分飽和状態で上限となるため、供給される排ガス中の水分濃度によって変化することとなる。すなわち、排ガス中の水分濃度によって、脱硫塔内の温度が変化することとなる。
(Function)
The decrease in the SO 2 removal performance of the desulfurizer due to the increase in the moisture concentration contained in the exhaust gas is mainly due to the temperature increase in the desulfurizer due to the increase in the moisture concentration. The structure of the wet desulfurization system is shown in FIG. 2. Exhaust gas at about 160 ° C. is supplied from the inlet duct, and the desulfurization absorption liquid is sprayed from the upper part of the desulfurization tower, so that SO 2 contained in the exhaust gas is absorbed by the desulfurization absorption liquid. , Have been removed.
At this time, a part of the desulfurization absorbing liquid evaporates, and the temperature of the exhaust gas decreases due to the latent heat of evaporation. Since the evaporation amount of the desulfurization absorption liquid becomes the upper limit in the water saturation state, it varies depending on the water concentration in the supplied exhaust gas. That is, the temperature in the desulfurization tower changes depending on the moisture concentration in the exhaust gas.
図3に排ガス中の水分濃度と脱硫塔内の温度との関係を示す。一般的な空気燃焼の場合は、排ガス中の水分濃度は11%であり、このときの脱硫塔内温度はおよそ50℃である。これに対し、酸素燃焼時は排ガス中の水分濃度が32%であり、脱硫塔内温度は75℃となることが分かる。さらに、脱硫塔内温度とSO2除去率との関係を図4に示すが、ガス温度が高くなるに従い、SO2除去率が低下することが分かる。これは、温度が高くなると、脱硫吸収液へのSO2溶解度が低下するためである。 FIG. 3 shows the relationship between the moisture concentration in the exhaust gas and the temperature in the desulfurization tower. In the case of general air combustion, the moisture concentration in the exhaust gas is 11%, and the temperature in the desulfurization tower at this time is about 50 ° C. On the other hand, at the time of oxyfuel combustion, the moisture concentration in the exhaust gas is 32%, and the temperature in the desulfurization tower is 75 ° C. Further, FIG. 4 shows the relationship between the temperature in the desulfurization tower and the SO 2 removal rate, and it can be seen that the SO 2 removal rate decreases as the gas temperature increases. This is because as the temperature increases, the solubility of SO 2 in the desulfurized absorbent decreases.
そこで、脱硫装置内に冷却構造を設置し、脱硫装置内部のガス温度を50℃に低減することで、酸素燃焼時においても、空気燃焼時と同等のSO2除去率を得ることが可能となる。 Therefore, by installing a cooling structure in the desulfurization apparatus and reducing the gas temperature inside the desulfurization apparatus to 50 ° C., it becomes possible to obtain an SO 2 removal rate equivalent to that in air combustion even during oxyfuel combustion. .
排ガス中の水分濃度を低減する方法として、排ガス循環ラインなどに、排ガス温度を低下させる冷却器を有する水分除去器等を設置する方法が考えられるが、この場合、伝熱管表面に及びその周囲のダクト表面に水分が凝縮することとなる。排ガス中には高濃度のSO2あるいはSO3が含まれているので、上記伝熱管表面及びダクト表面に凝縮した水分がSO2、SO3を吸収し、酸性水となり、伝熱管表面及びダクト表面の腐食が問題となる。また、回収した硫黄分を含んだ多量の水を処理するための処理装置も必要となる。 As a method of reducing the moisture concentration in the exhaust gas, a method of installing a moisture remover or the like having a cooler for lowering the exhaust gas temperature in the exhaust gas circulation line, etc. can be considered. Water will condense on the duct surface. Since the exhaust gas contains high-concentration SO 2 or SO 3 , moisture condensed on the heat transfer tube surface and duct surface absorbs SO 2 and SO 3 and becomes acidic water, and the heat transfer tube surface and duct surface Corrosion becomes a problem. In addition, a treatment apparatus for treating a large amount of water containing the recovered sulfur content is also required.
これらの問題に対し、本発明では、排ガス中の水分は脱硫吸収液に混入することとなる。脱硫装置の脱硫吸収液は、pHが5.5〜6.0程度になるように調整しているため、腐食等の問題はほとんど無い。また、もともとSO2を吸収、処理するための装置であるため、排水処理装置も設置してあり、新たな機器を設ける必要もない。
上記脱硫装置内に設ける冷却器の構造は、脱硫吸収液のタンク内部に伝熱管を設置し、伝熱管内部に冷却水を供給することで、脱硫吸収液を50℃以下にする方法が有効である。
With respect to these problems, in the present invention, moisture in the exhaust gas is mixed into the desulfurization absorbent. Since the desulfurization absorption liquid of the desulfurization apparatus is adjusted so that the pH is about 5.5 to 6.0, there are almost no problems such as corrosion. Moreover, since it is an apparatus for absorbing and treating SO 2 originally, a waste water treatment apparatus is also installed, and it is not necessary to provide new equipment.
As a structure of the cooler provided in the desulfurization apparatus, it is effective to install a heat transfer pipe inside the tank of the desulfurization absorption liquid and supply the cooling water to the heat transfer pipe to make the desulfurization absorption liquid 50 ° C. or less. is there.
請求項1、2記載の発明によれば、酸素燃焼排ガスのように水分濃度が30%と高い場合においても、脱硫装置を50℃に維持することができ、そのため、脱硫装置の大きさを変えることなく、空気燃焼時と同等のSO2除去率を達成することが可能となる。 According to the first and second aspects of the invention, even when the moisture concentration is as high as 30% as in the case of oxyfuel exhaust gas, the desulfurization apparatus can be maintained at 50 ° C., and therefore the size of the desulfurization apparatus is changed. Therefore, the SO 2 removal rate equivalent to that during air combustion can be achieved.
請求項記載の発明によれば 湿式排煙脱硫装置内に設ける冷却器に用いる熱交換用冷媒は、ボイラ復水を用い、該冷却器で吸収液の冷却に利用したボイラ水をボイラに循環使用することで省資源化が図れる。 According to the first and second aspects of the present invention, the heat exchange refrigerant used in the cooler provided in the wet flue gas desulfurization apparatus uses boiler condensate, and boiler water used for cooling the absorption liquid by the cooler is used as the boiler. In addition, resource saving can be achieved by recycling.
本発明の一実施例の排ガス処理装置の構成を示す。The structure of the waste gas processing apparatus of one Example of this invention is shown. 図1に装置に用いられる脱硫装置の詳細構造を示す。FIG. 1 shows a detailed structure of a desulfurization apparatus used in the apparatus. 排ガス中水分濃度と脱硫塔内の温度との関係を示す。The relationship between the moisture concentration in exhaust gas and the temperature in a desulfurization tower is shown. 排ガス温度とSO2除去率との関係を示す。It shows the relationship between exhaust gas temperature and the SO 2 removal rate. 本発明の一実施例の排ガス処理装置の構成を示す。The structure of the waste gas processing apparatus of one Example of this invention is shown. 従来の排ガス処理装置の構成を示す。The structure of the conventional waste gas processing apparatus is shown.
本発明の実施例を図面と共に説明する。
図1には本実施例の排ガス処理装置の全体構成図を示す。本実施例の排ガス処理装置は、図6に示した従来の排ガス処理装置の構成の脱硫装置5に熱交換器23を追加した構成からなる。
熱交換器23に用いる熱交換用冷媒は、図示していないが、復水器(図示せず)からボイラ1の蒸発器に供給するボイラ水の一部を使用し、熱回収した熱をボイラ側で利用するできる構成としている。
本実施例の脱硫装置5の詳細構造を図2に示す。脱硫装置5の下部に設置している吸収液タンク29の内部に本実施例の熱交換器23を設置している。
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall configuration diagram of an exhaust gas treatment apparatus of the present embodiment. The exhaust gas treatment apparatus of this embodiment has a configuration in which a heat exchanger 23 is added to the desulfurization device 5 having the configuration of the conventional exhaust gas treatment apparatus shown in FIG.
Although the refrigerant for heat exchange used for the heat exchanger 23 is not shown, a part of boiler water supplied from the condenser (not shown) to the evaporator of the boiler 1 is used, and the heat recovered by the boiler is used. It can be used on the side.
The detailed structure of the desulfurization apparatus 5 of a present Example is shown in FIG. The heat exchanger 23 of the present embodiment is installed inside the absorbing liquid tank 29 installed at the lower part of the desulfurization apparatus 5.
本実施例の場合、排ガス循環量は全ガス量の80%であり、排ガス組成は表1に示す通りであった。
In this example, the exhaust gas circulation amount was 80% of the total gas amount, and the exhaust gas composition was as shown in Table 1.
ボイラ1より発生した排ガスは、脱硝装置2で排ガス中のNOxが低減され、空気加熱器(A/H)3でガス温度が160℃に低下された後、集塵機4で排ガス中のダストが除去される。
集塵機4の後流側の排ガスの80%を再循環ライン8に供給し、再循環用ファン9によってボイラ1に戻し、ボイラ燃焼部に供給する。集塵機4の後流側の残り20%の排ガスは、脱硫装置5に供給される。脱硫装置5には温度160℃、水分濃度30%の排ガスが供給される。
The exhaust gas generated from the boiler 1 is reduced in NOx in the exhaust gas by the denitration device 2, the gas temperature is lowered to 160 ° C. by the air heater (A / H) 3, and then the dust in the exhaust gas is removed by the dust collector 4. Is done.
80% of the exhaust gas on the downstream side of the dust collector 4 is supplied to the recirculation line 8, returned to the boiler 1 by the recirculation fan 9, and supplied to the boiler combustion section. The remaining 20% of the exhaust gas on the downstream side of the dust collector 4 is supplied to the desulfurization device 5. The desulfurization apparatus 5 is supplied with exhaust gas having a temperature of 160 ° C. and a moisture concentration of 30%.
本実施例では、排ガス中の水分は脱硫吸収液に混入しているが、吸収液タンク29内の脱硫吸収液28は、pHが5.5〜6.0程度になるように調整しているため、吸収液タンク29内に設ける熱交換器23は腐蝕等の問題はほとんど無い。   In this embodiment, the moisture in the exhaust gas is mixed in the desulfurization absorption liquid, but the desulfurization absorption liquid 28 in the absorption liquid tank 29 is adjusted to have a pH of about 5.5 to 6.0. Therefore, the heat exchanger 23 provided in the absorbing liquid tank 29 has almost no problem such as corrosion.
上記脱硫装置5内に設ける熱交換器23の構造は、脱硫吸収液28のタンク29内部に伝熱管を設置し、伝熱管内部に冷却水25を供給することで、脱硫吸収液28を50℃以下にする方法が有効であり、該冷却用熱交換器23を用いて吸収液タンク29内の吸収液28を50℃まで冷却することで、SO2除去性能を向上できることが確認できた。 The structure of the heat exchanger 23 provided in the desulfurization apparatus 5 is such that a heat transfer pipe is installed inside the tank 29 of the desulfurization absorption liquid 28 and the cooling water 25 is supplied into the heat transfer pipe so that the desulfurization absorption liquid 28 is 50 ° C. It was confirmed that the following method is effective, and that the SO 2 removal performance can be improved by cooling the absorbent 28 in the absorbent tank 29 to 50 ° C. using the cooling heat exchanger 23.
本発明の他の実施例を図5に示す。図5に示す実施例は、図1に示す排ガス処理装置に比較して再循環ライン8を脱硫装置5の前流側でなく、脱硫装置5の後流側の排ガス流路に設置したことが相違する例である。この場合、排ガスの全量が脱硫装置5に供給されることとなるが、脱硫装置5の内部に熱交換器23という冷却構造を設置することで、脱硫装置5の内部温度を50℃に維持することができ、空気燃焼時と同等のSO2除去率を得ることができる。 Another embodiment of the present invention is shown in FIG. In the embodiment shown in FIG. 5, the recirculation line 8 is installed not in the upstream side of the desulfurization device 5 but in the exhaust gas flow path on the downstream side of the desulfurization device 5 as compared with the exhaust gas treatment device shown in FIG. This is a different example. In this case, the entire amount of exhaust gas is supplied to the desulfurization device 5, but the internal temperature of the desulfurization device 5 is maintained at 50 ° C. by installing a cooling structure called a heat exchanger 23 inside the desulfurization device 5. And an SO 2 removal rate equivalent to that during air combustion can be obtained.
酸素燃焼方式の石炭焚ボイラでは、燃焼場の温度を下げるために、排ガスを循環させる必要がある。このような排ガスを循環する酸素燃焼の場合、排ガス組成が従来の空気燃焼方式に比べて大きく異なることとなる。排ガスの大部分がCO2になるだけでなく、酸素燃焼及び排ガス循環運転を行うために、排ガス中の水分濃度とSO2濃度が高くなるが、本発明は、これらの課題を解決する手法の一つとして産業上の利用可能性が高い。 In an oxyfuel combustion coal fired boiler, it is necessary to circulate exhaust gas in order to lower the temperature of the combustion field. In the case of oxyfuel combustion in which such exhaust gas is circulated, the exhaust gas composition is greatly different from that of the conventional air combustion system. Most of the exhaust gas not only becomes CO 2 , but also performs oxygen combustion and exhaust gas circulation operation, so that the water concentration and SO 2 concentration in the exhaust gas become high. The present invention is a method for solving these problems. As one, the industrial applicability is high.
1 ボイラ 2 脱硝装置
3 空気加熱器(A/H) 4 集塵機
5 脱硫装置 6 CO2圧縮機
8 循環ライン 9 循環用ファン
21 石炭 22 酸素
23 熱交換器 25 冷却水
28 脱硫吸収液 29 吸収液タンク
1 boiler 2 denitration apparatus 3 air heater (A / H) 4 dust collector 5 desulfurizer 6 CO 2 compressor 8 circulation line 9 circulation fans 21 coal 22 oxygen 23 heat exchanger 25 cooling water 28 desulfurization absorbing fluid 29 absorbs liquid tank

Claims (2)

  1. 石炭を酸素を酸化剤として燃焼させて蒸気を発生するボイラと、
    該ボイラからの排ガス中の窒素酸化物を除去する脱硝装置と、
    排ガス中の硫黄酸化物を吸収液を排ガス中に噴霧することで除去する湿式排煙脱硫装置と、
    湿式排煙脱硫装置内の吸収液の冷却をする吸収液冷却装置と、
    湿式排煙脱硫装置の前流側又は後流側の排ガスの一部をボイラ燃焼部に循環する排ガス循環ラインと
    を備えた酸素燃焼用石炭焚ボイラの排ガス処理装置において、
    ボイラで生成した蒸気を蒸気利用機器で使用した後に復水させる復水器を設け、該復水器出口のボイラ水を、前記湿式排煙脱硫装置内の貯留吸収液冷却用の吸収液冷却装置を経由してボイラに再循環する冷却水流路を配置したことを特徴とする酸素燃焼用石炭焚ボイラの排ガス処理装置。
    A boiler that generates steam by burning coal using oxygen as an oxidant;
    A denitration device for removing nitrogen oxides in the exhaust gas from the boiler;
    A wet flue gas desulfurization device that removes sulfur oxides in exhaust gas by spraying the absorbing liquid into the exhaust gas;
    And absorbing liquid cooling device for cooling the absorbent liquid in the wet type exhaust gas desulfurization apparatus,
    In an exhaust gas treatment apparatus for an oxyfuel coal fired boiler comprising an exhaust gas circulation line for circulating a part of the exhaust gas on the upstream side or the downstream side of the wet flue gas desulfurization apparatus to the boiler combustion section ,
    An absorption liquid cooling device for cooling the stored absorption liquid in the wet flue gas desulfurization apparatus is provided, in which a condenser for condensing the steam generated in the boiler after being used in the steam utilization device is provided. An exhaust gas treatment apparatus for a coal fired boiler for oxyfuel combustion, characterized in that a cooling water flow path that recirculates to the boiler via an exhaust is disposed .
  2. 石炭を酸素を酸化剤として燃焼させて蒸気を発生するボイラからの排ガス中の窒素酸化物を脱硝装置で除去し、
    湿式排煙脱硫装置で排ガス中の硫黄酸化物を吸収液を排ガス中に噴霧することで除去し、
    湿式排煙脱硫装置の前流側又は後流側の排ガスの一部をボイラ燃焼部に循環し、
    湿式排煙脱硫装置内の吸収液を冷却して50℃以下にする酸素燃焼用石炭焚ボイラの排ガス処理方法において、
    ボイラで生成した蒸気を蒸気利用機器で使用した後に復水させる復水器出口のボイラ水を湿式排煙脱硫装置内の吸収液中に導き、吸収液を冷却して50℃以下にすることを特徴とする酸素燃焼用石炭焚ボイラの排ガス処理方法
    Nitrogen oxides in exhaust gas from boilers that generate steam by burning coal using oxygen as an oxidant are removed with a denitration device ,
    We remove sulfur oxides in exhaust gas by spraying absorption liquid into exhaust gas with wet flue gas desulfurization equipment ,
    Circulating a part of the exhaust gas on the upstream or downstream side of the wet flue gas desulfurization unit to the boiler combustion section,
    In the exhaust gas treatment method for a coal fired boiler for oxyfuel combustion, the absorbent in the wet flue gas desulfurization apparatus is cooled to 50 ° C. or lower.
    The boiler water at the outlet of the condenser that condenses the steam generated in the boiler after being used in the steam-utilizing equipment is guided into the absorbing liquid in the wet flue gas desulfurization device, and the absorbing liquid is cooled to 50 ° C. or lower. exhaust gas treatment process of the coal-fired boiler for oxygen combustion shall be the features.
JP2009021630A 2009-02-02 2009-02-02 Exhaust gas treatment apparatus and method for oxyfuel coal fired boiler Expired - Fee Related JP5275064B2 (en)

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