201231147 六、發明說明： 【發明所屬之技術領域】 本發明是關於一種排放氣體處理方法及裝置，特別是 關於一種排煙處理設備，該排煙處理設備是減低含有於排 放氣體中的NOx、SOx、煤塵及造粒工場等所使用的燃料 中的成分或物質。 【先前技術】 由製造在煉鐵廠所使用的鐵鑛石造粒的造粒工場等所 排出的排放氣體，是溫度比來自使用化石燃料等的燃燒裝 置的排放氣體還要低。在此些排放氣體與來自燃燒裝置的 排放氣體同樣地含有氮氧化物（NOx )或是硫磺氧化物（ S Ox )之故，因而爲了防止大氣污染必須除去NOx或S Ox 〇 將一般性的排放氣體處理系統的系統表示於第7圖。 在該排放氣體處理系統中，由造粒工場1等所排出的排放 氣體是以電氣集塵器2除去排放氣體中的煤塵之後，被導 入至濕式排煙脫硫裝置7，與被噴霧於排煙脫硫裝置7內 的脫硫劑漿液做氣液接觸，而被去除排放氣體中的SOx。 在排煙脫硫裝置7被處理的排放氣體，是其溫度下降至飽 和溫度之故，因而利用風扇3被送到氣體與氣體熱交換器 4 ’然後利用排放氣體加熱燃燒器5，被加熱直到脫硝裝置 ό所需要的溫度爲止。又’經由電氣集塵器2的排放氣體 未經由排煙脫硫裝置7，而也有直接利用風扇3被送到氣 -5- 201231147 體與氣體熱交換器4的情形。被加熱的排放氣體是被導入 至脫硝裝置6而藉由排放氣體中的NOx與脫硝觸媒接觸 後被除掉，再次經氣體與氣體熱交換器4，從煙囪8被排 出。 專利文獻1 :日本特開2000-300961 【發明內容】 通過表示於第7圖的濕式排煙脫硫裝置7的排放氣體 ，是被冷卻直到飽和溫度爲止之故，因而爲了防止脫硝裝 置6內的脫硝催化上生成酸性硫酸銨所需要的溫度爲止， 必須組合氣體與氣體熱交換器4與排放氣體加熱燃燒器5 進行再加熱，而有需要使用很多燃料之問題點。 排放氣體加熱燃燒器5，是設置於排煙脫硫裝置7之 下游側的排放氣體流路中之故，因而利用排放氣體加熱燃 燒器5之燃燒所生成的S Ox是不會被除去而被排出。限制 排出的問題上，因減低在排放氣體加熱燃燒器5之燃燒所 生成的SOx，因此必須使用硫磺分含有量低之高品位的燃 料。 在本發明的課題，是提供一種排放氣體處理方法及裝 置，該排放氣體處理方法及裝置，是即使有從燃燒裝置以 外之處理氣體所發生的裝置被排出的排放氣體，也可用以 進行該排放氣體中的脫硫與脫硝》 欲解決上述的問題，將濕式排煙脫硫裝置7設置於脫 硝裝置6之下游就可以解決。 -6- 201231147 如申請專利範圍第1項所述的發明，是一種排放氣體 處理方法，其特徵爲：在煉鐵工序，對從燒結鐵鑛石的設 備或是鍋爐所排出的排放氣體進行除塵處理之後，以排放 氣體加熱燃燒器（5)進行加熱，使用脫硝觸媒來除去排 放氣體中的氮氧化物，並以熱交換來回收經除去氮氧化物 之後的排放氣體之熱能，並將之利用於使用上述脫硝觸媒 用以除去排放氣體中的氮氧化物之排放氣體的加熱，然後 使用含有石灰石或石灰之漿液所成的吸收液來吸收或除去 由利用上述熱交換降低溫度後之排放氣體中的硫磺氧化物 及其他成分所起因的物質。 如申請專利範圍第2項所述的發明，是如申請專利範 圍第1項所述的排放氣體處理方法，其中，將使用上述脫 硝觸媒來除去排放氣體中的氮氧化物之後的排放氣體之熱 能，再次利用於使用上述脫硝觸媒來除去排放氣體中的氮 氧化物之後，更藉由熱交換回收熱能而利用於上述排放氣 體加熱燃燒器（5)的燃燒用空氣（11)的加熱。 如申請專利範圍第3項所述的發明，是如申請專利範 圍第2項所述的排放氣體處理方法，其中，藉由上述熱交 換回收熱能而利用於上述排放氣體加熱燃燒器（5 )的燃 燒用空氣（1 1 )之加熱，使降低溫度後的排放氣體，與含 有上述石灰石或石灰之漿液所成的吸收液接觸，來吸收或 除去由來自該排放氣體之硫磺氧化物及其他成分所起因的 物質。 如申請專利範圍第4項所述的發明，是一種排放氣體 201231147 處理裝置，其特徵爲：配置有：集塵器（2)、及排放氣 體加熱燃燒器（5)、及脫硝裝置（6)、及氣體與氣體熱 交換器（4)、以及濕式排煙脫硫裝置（7)，該集塵器（ 2)，是對於在煉鐵工序中，輸送由燒結鐵鑛石的設備或 是鍋爐所排出的排放氣體的排放氣體流路，進行排放氣體 之除塵處理，該排放氣體加熱燃燒器（5)，是將該集塵 器（2)的出口排放氣體予以加熱，該脫硝裝置（6)，是 將除去以該排放氣體加熱燃燒器（5 )所加熱的排放氣體 中之氮氧化物的脫硝觸媒予以塡充，該氣體與氣體熱交換 器（4)，是從該脫硝裝置（6)的出口排放氣體進行熱回 收，並將脫硝裝置（6 )之入口排放氣體予以加熱，該濕 式排煙脫硫裝置（7)，是導入該氣體與氣體熱交換器（4 )的出口排放氣體，並使用含有石灰石或石灰之漿液所成 的吸收液來吸收或除去由排放氣體中的硫磺氧化物及其他 成分所起因的物質。 如申請專利範圍第5項所述的發明，是如申請專利範 圍第4項所述的排放氣體處理裝置，其中，在上述氣體與 氣體熱交換器（4)出口的排放氣體流路中設置第2氣體 與氣體熱交換器（9)，在供給於該第2氣體與氣體熱交 換器（9)與排放氣體加熱燃燒器（5)之燃燒用空氣（11 )的導入路，設置氣體與氣體熱再熱器（10)，以熱媒體 流路（13)連接該氣體與氣體熱再熱器（1〇)。 如申請專利範圍第6項所述的發明，是如申請專利範 圍第5項所述的排放氣體處理裝置，其中，將第2氣體與 201231147 氣體熱交換器（9 )的出口側之溫度降低後的排放氣體流 路連接於濕式排煙脫硫裝置（7)。 如申請專利範圍第7項所述的發明，是如申請專利範 圍第4項所述的排放氣體處理裝置，其中，在上述氣體與 氣體熱交換器（4)出口的排放氣體流路設置用來加熱排 放氣體加熱燃燒器（5 )之燃燒用空氣（1 1 )的空氣加熱 器（12)，並設置將以該空氣加熱器（12)加熱後的空氣 供給至排放氣體加熱燃燒器（5)之燃燒用空氣流路。 依照如申請專利範圍第1項及第4項所述的發明，將 濕式排煙脫硫裝置7設置於脫硝裝置6的下游側的排放氣 體流路中，就成爲可防止降低氣體與氣體熱交換器4之入 口的排放氣體溫度。藉此，不但可減小氣體與氣體熱交換 器4的規格，還可減低排放氣體加熱燃燒器5的燃料使用 量。 又不但於排放氣體加熱燃燒器5可使用含有多量硫磺 分的重油等的廣泛種類的燃料，還可使氣體與氣體熱交換 器4的入口排放氣體成爲乾燥排放氣體之故，因而選定氣 體與氣體熱交換器4的材料成爲容易。 依照如申請專利範圍第2項及第5項以及第7項所述 的發明，將使用脫硝觸媒而被使用於除去排放氣體中的氮 氧化物之後的排放氣體之熱能，爲了再次加熱脫硝觸媒經 熱交換被利用之後，被利用於排放氣體加熱燃燒器5的燃 燒用空氣11之加熱，就可以將至今未被使用的熱能有效 地利用。 -9 - 201231147 依照如申請專利範圍第3項及第6項所述的發明，將 濕式排煙脫硫裝置7設置於脫硝裝置6的下游側的排放氣 體流路中，就可成爲也可除去在排放氣體加熱燃燒器5所 發生的SOx，若將在煙囪8之入口的SOx濃度作爲50ppm 時，則在排煙脫硫裝置7中所需要的脫硫性能是成爲大約 95%’而成爲可將需要脫硫性能大約減低3%。 【實施方式】 將本發明的實施例與圖式一起說明。 實施例1 將依本發明的排放氣體處理系統表示於第1圖。來自 製造在煉鐵廠所使用的鐵鑛石造粒的造粒工場1的排放氣 體流路中，將氣體與氣體熱交換器4設置於使用眾所周知 的石灰石漿液等的濕式排煙脫硫裝置7之上游側，並將濕 式排煙脫硫裝置7設置於配置眾所周知之脫硝觸媒的脫硝 裝置6的下游側。又，在第1圖等所說明的裝置發揮與表 示於第7圖的裝置相同功能的裝置，給予同一號碼，而有 省略其說明的情形。 於第2圖表示氣體與氣體熱交換器4周圍的溫度平衡 的例子。第2(b)圖是在從來的排放氣體處理系統中，於 排煙脫硫裝置7之下游側的排放氣體流路設置脫硝裝置6 時的溫度平衡，惟排出排煙脫硫裝置7的排放氣體之溫度 ，是硫磺氧化物與氮氧化物所飽和的飽和氣體而在氣體與 -10- 201231147 氣體熱交換器4之正前就下降至大約5 0°C。 必須將該排放氣體加熱至爲了脫硝處理所必需之溫度 的大約350°C爲止之故，因而在其加熱以組合氣體與氣體 熱交換器4與排放氣體加熱燃燒器5就可進行，惟溫度上 昇幅度大之故，因而氣體與氣體熱交換器4的規格會變大 ，或是多量地使用排放氣體加熱燃燒器5的燃料之故，因 而未具經濟性。又，因排放氣體爲以硫磺氧化物與氧氧化 物所飽和，因此，於氣體與氣體熱交換器4的材質上必須 採用耐腐蝕性的材質而未具經濟性。 在表示於第2 ( a )圖的本發明之實施例的裝置，利用 將排煙脫硫裝置7設置於脫硝裝置6之下游側的排放氣體 流路中，脫硝裝置6之正前的氣體與氣體熱交換器4之入 口的排放氣體溫度是15(TC，不但可減小氣體與氣體熱交 換器4之規格，還成爲可減低在排放氣體加熱燃燒器5所 使用的燃料之使用量。 還有，在從來的排放氣體處理裝置中，因將排煙脫硫 裝置7設置於脫硝裝置6之正前的排放流路，因此，以硫 磺氧化物與氮氧化物所飽和的排放氣體被導入至氣體與氣 體熱交換器4。所以，在氣體與氣體熱交換器4中，必須 考慮到選定耐腐蝕性的材料。 在本發明之裝置，利用將排煙脫硫裝置7設置在脫硝 裝置6之下游側的排放氣體流路中，因在氣體與氣體熱交 換器4導入有經乾燥之排放氣體，因此，成爲可容易地選 定氣體與氣體熱交換器4之材料。 -11 - 201231147 又，在本實施例的裝置，利用將排煙脫硫裝置7設置 在脫硝裝置6之下游側的排放氣體流路中，成爲也可除去 在排放氣體加熱燃燒器5所生成的S Ox。藉此，成爲將含 有硫磺分的燃料等廣泛之燃料可使用於排放氣體加熱燃燒 器5。 於第3圖表示排煙處理系統的SOx濃度的平衡。第3 (b)圖是將從來的濕式排煙脫硫裝置7設置在脫硝裝置6 之上游時的SOx濃度的平衡的例子。因於排煙脫硫裝置7 的下游側的排放氣體流路設置有排放氣體加熱燃燒器5, 因此，將含有硫磺分的重油使用於排放氣體加熱燃燒器5 的燃料時，在燃燒排放氣體加熱燃燒器5的燃料所發生的 大約1 200ppm之高濃度的SOx並不會被處理，而被導入 至煙囪8。將煙_ 8之入口的SOx濃度作爲50ppm時，考 慮到來自排放氣體加熱燃燒器5所排出的排放氣體中之 SOx而必須決定排煙脫硫裝置7的所需性能，在本例子中 ，在排煙脫硫裝置7中成爲需要大約98 %的脫硫性能。 表示於第3(a)圖的本實施例的裝置中，將排煙脫硫 裝置7設置在脫硝裝置6之下游側的排放氣體流路，就成 爲也可除去在排放氣體加熱燃燒器5所發生的SOx，將在 煙囪8入口的SOx濃度作爲50ppm時，在排煙脫硫裝置7 中所需要的脫硫性能是成爲大約9 5 %。在本實施例中成爲 可將必需脫硫性能減低大約3 %。 在第4圖表示必需脫硫性能與在排煙脫硫裝置7的石 灰石漿液等所成的吸收液循環液量[對於被導入至排煙脫 -12- 201231147 硫裝置7內的排放氣體噴霧上述吸收液，進行氣液接觸所 導致的脫硫反應，並將掉落的吸收液儲存在脫硫裝置下部 之儲備槽（未予以圖示）之後，爲了對於排放氣體噴霧多 次使之循環]之關係，惟藉由使必需脫硫性能由98 %降低 3 %至95%，成爲可將吸收液循環液量減低大約20%，可減 低耗電量或是減低循環吸收液泵浦之台數。 實施例2 將本發明的其他實施例表示於第5圖。表示於第5圖 的排煙處理系統，是在表示於第1圖的排煙處理系統將第 2氣體與氣體熱交換器9配置在脫硝裝置6之下游側而位 於脫硫裝置7之上游側的排放氣體流路中的例子。 在表示於第5(a)圖的例子中，配置在脫硝裝置6之 下游側的排放氣體流路中的第2氣體與氣體熱交換器9之 出口的排放氣體是200°C左右，而該排放氣體爲被導入至 濕式排煙脫硫裝置7，被冷卻直到飽和溫度爲止，之後從 煙囪8被排出。在本實施例中，在排煙脫硫裝置7之正前 的排放氣體流路中設置第2氣體與氣體熱交換器9,將在 氣體與氣體熱交換器4所回收的熱能由熱媒體流路13供 給至氣體與氣體再加熱器10，然後使用於排放氣體加熱燃 燒器5之燃燒用空氣11的預熱，成爲可將至今還未被使 用的熱能有效地利用。 如第5(b)圖所示地，除了氣體與氣體熱交換器4以 外還使用排放氣體加熱用空氣加熱器12，也可使用於排放 -13- 201231147 氣體加熱燃燒器5之燃燒用空氣11的預熱。 又，排放氣體是在排煙脫硫裝置7被冷卻之際使多量 蒸發水成爲從煙囪8被排出。於第6圖表示排煙脫硫裝置 7的入口溫度與蒸發水量之關係。對於以排放氣體溫度爲 200°C被導入至排煙脫硫裝置7時蒸發大約150t/h的水， 而以排放氣體溫度爲l〇〇°C時成爲蒸發大約50t/h的水。 在本實施例中，將氣體與氣體熱交換器4設置於濕式 排煙脫硫裝置7之正前，就可藉由降低被導入至排煙脫硫 裝置7的排放氣體溫度而可減低蒸發水量，成爲可減低在 排煙處理系統之水的消耗量。 作爲有效率地可處理由造粒製造廠等所排出的低溫度 排放氣體中的NOx、S Ox的設備，本發明是有高利用可能 性。 【圖式簡單說明】 第1圖是表示作爲本發明的排放氣體處理裝置的系統 的圖式。 第2圖是表示本發明[第2 ( a)圖]及從來技術[第2 ( b)圖]的排放氣體處理裝置之溫度平衡的圖式。 第3圖是表示本發明[第3 ( a)圖]及從來技術[第3 ( b)圖]所構成的排放氣體處理裝置的SOx濃度平衡的圖式 〇 第4圖是表示脫硫性能與排煙脫硫裝置的吸收液循環 液量之關係的圖式 -14 - 201231147 第5(a)圖與第5(b)圖都是在作爲本發明的排放 氣體處理裝置追加GGH熱回收器-再加熱器的圖式。 第6圖是表示排煙脫硫裝置的入口排放氣體溫度與蒸 發水量之關係的圖式。 第7圖是表示從來之排放氣體處理裝置的系統的圖式 【主要元件符號說明】 1 ·造粒工場 2 :電氣集塵器 3 :風扇 氣體與氣體熱交換器 5 ’·排放氣體加熱燃燒器 6 :脫硝裝置 7 :濕式排煙脫硫裝置 8 :煙囪 9 :第2氣體與氣體熱交換器 1〇:再加熱器（再熱器） 1 1 :燃燒用空氣 12:排放氣體加熱用空氣加熱器 1 3 :熱媒體流路 -15-201231147 VI. Description of the Invention: [Technical Field] The present invention relates to an exhaust gas treatment method and apparatus, and more particularly to a smoke exhaust treatment apparatus for reducing NOx, SOx contained in exhaust gas Components or substances in fuels used in coal dust and granulation workshops. [Prior Art] The exhaust gas discharged from a granulation plant or the like which produces iron ore granulation used in an ironworks is lower in temperature than the exhaust gas from a combustion apparatus using fossil fuel or the like. These exhaust gases contain nitrogen oxides (NOx) or sulfur oxides (S Ox ) in the same manner as the exhaust gases from the combustion devices. Therefore, in order to prevent atmospheric pollution, it is necessary to remove NOx or S Ox . The system of the gas treatment system is shown in Figure 7. In the exhaust gas treatment system, the exhaust gas discharged from the granulation plant 1 or the like is removed by the electric dust collector 2 to remove the coal dust in the exhaust gas, and then introduced into the wet flue gas desulfurization device 7, and is sprayed on The desulfurizer slurry in the flue gas desulfurization device 7 is brought into gas-liquid contact, and the SOx in the exhaust gas is removed. The exhaust gas to be treated in the flue gas desulfurization device 7 is such that its temperature drops to a saturation temperature, and thus is sent to the gas and gas heat exchanger 4' by the fan 3, and then the burner 5 is heated by the exhaust gas, and is heated until The denitration device is at the temperature required by the denitrification device. Further, the exhaust gas passing through the electric dust collector 2 is not directly supplied to the gas-5-201231147 body and gas heat exchanger 4 by the exhaust gas desulfurization device 7, but also directly by the fan 3. The heated exhaust gas is introduced into the denitration device 6 and is removed by contact with the denitration catalyst in the exhaust gas, and is again discharged from the stack 8 through the gas and gas heat exchanger 4. Patent Document 1: JP-A-2000-300961 SUMMARY OF THE INVENTION The exhaust gas of the wet flue gas desulfurization device 7 shown in Fig. 7 is cooled to a saturation temperature, and thus the denitration device 6 is prevented. The internal denitration catalyzes the temperature required to form the acidic ammonium sulfate, and the gas and gas heat exchanger 4 and the exhaust gas heating burner 5 must be combined for reheating, and there is a problem that a lot of fuel is required. The exhaust gas heating burner 5 is disposed in the exhaust gas flow path on the downstream side of the exhaust gas desulfurization device 7, and thus the S Ox generated by the combustion of the exhaust gas heating burner 5 is not removed. discharge. In order to limit the problem of discharge, since the SOx generated by the combustion of the exhaust gas heating burner 5 is reduced, it is necessary to use a high-grade fuel having a low sulfur content. An object of the present invention is to provide an exhaust gas treatment method and apparatus which can be used to discharge an exhaust gas even if a device is generated from a process gas other than a combustion device. Desulfurization and Denitrification in Gas To solve the above problem, the wet flue gas desulfurization device 7 can be disposed downstream of the denitration device 6. -6- 201231147 The invention described in claim 1 is an exhaust gas treatment method, characterized in that: in the iron making process, dust is discharged from exhausted iron ore equipment or boiler exhaust gas After the treatment, the exhaust gas is heated by the exhaust gas heating burner (5), the denitration catalyst is used to remove the nitrogen oxides in the exhaust gas, and the heat energy of the exhaust gas after the removal of the nitrogen oxides is recovered by heat exchange, and The use of the above-mentioned denitration catalyst for removing the exhaust gas of the nitrogen oxides in the exhaust gas, and then using the absorption liquid containing the slurry of limestone or lime to absorb or remove the temperature after the temperature is lowered by using the above heat exchange. A substance caused by sulfur oxides and other components in the exhaust gas. The invention according to claim 2, wherein the exhaust gas treatment method according to the first aspect of the invention, wherein the denitration catalyst is used to remove exhaust gas after exhausting nitrogen oxides in the exhaust gas The heat energy is reused for removing the nitrogen oxides in the exhaust gas by using the above-mentioned denitration catalyst, and further recovering the heat energy by heat exchange to utilize the combustion air (11) of the exhaust gas heating burner (5). heating. The invention of claim 3, wherein the exhaust gas treatment method according to claim 2, wherein the heat recovery is performed by the heat exchange to utilize the exhaust gas heating burner (5) Heating the combustion air (1 1 ) to bring the exhaust gas after the temperature decrease to contact with the absorption liquid formed by the slurry containing the limestone or lime to absorb or remove the sulfur oxides and other components from the exhaust gas. The cause of the substance. The invention according to claim 4 is an exhaust gas 201231147 processing apparatus, which is characterized in that: a dust collector (2), an exhaust gas heating burner (5), and a denitration device (6) are disposed. And a gas and gas heat exchanger (4) and a wet flue gas desulfurization device (7) for transporting the sintered iron ore in the iron making process or It is an exhaust gas flow path of the exhaust gas discharged from the boiler, and performs a dust removal process of the exhaust gas, and the exhaust gas heats the burner (5) to heat the outlet gas of the dust collector (2), and the denitration device (6), wherein the denitration catalyst that removes nitrogen oxides in the exhaust gas heated by the exhaust gas heating burner (5) is charged, and the gas and gas heat exchanger (4) is from the The outlet exhaust gas of the denitration device (6) is subjected to heat recovery, and the inlet exhaust gas of the denitration device (6) is heated, and the wet flue gas desulfurization device (7) is introduced into the gas and gas heat exchanger. (4) The outlet emits gas and uses limestone The lime slurry of the absorbing liquid to absorb into or remove substances from the exhaust gas of sulfur oxides and other components of the cause. The invention of claim 5, wherein the exhaust gas treatment device according to the fourth aspect of the invention, wherein the gas and gas heat exchanger (4) outlets are disposed in an exhaust gas flow path 2 gas and gas heat exchanger (9), gas and gas are provided in an introduction path of combustion air (11) supplied to the second gas and gas heat exchanger (9) and the exhaust gas heating burner (5) The heat reheater (10) is connected to the gas and gas heat reheater (1〇) by a heat medium flow path (13). The invention according to claim 5, wherein the temperature of the outlet gas of the second gas and the 201231147 gas heat exchanger (9) is lowered after the temperature of the outlet gas side of the second gas and the 201231147 gas heat exchanger (9) is reduced. The exhaust gas flow path is connected to the wet flue gas desulfurization device (7). The invention of claim 4, wherein the exhaust gas treatment device of the gas and gas heat exchanger (4) outlet is provided for use in the exhaust gas treatment device according to the fourth aspect of the invention. Heating the exhaust gas to heat the air heater (12) of the combustion air (1 1 ) of the burner (5), and providing the air heated by the air heater (12) to the exhaust gas heating burner (5) The air flow path for combustion. According to the invention described in the first and fourth aspects of the patent application, the wet flue gas desulfurization device 7 is disposed in the exhaust gas flow path on the downstream side of the denitration device 6, thereby preventing the gas and gas from being lowered. The temperature of the exhaust gas at the inlet of the heat exchanger 4. Thereby, not only the specification of the gas and gas heat exchanger 4 but also the fuel usage of the exhaust gas heating burner 5 can be reduced. Further, not only the exhaust gas heating burner 5 can use a wide variety of fuels such as heavy oil containing a large amount of sulfur fraction, but also the inlet exhaust gas of the gas and gas heat exchanger 4 can be made into a dry exhaust gas, and thus the selected gas and gas are selected. The material of the heat exchanger 4 becomes easy. According to the invention described in the second and fifth aspects and the seventh aspect of the patent application, the heat energy of the exhaust gas after the removal of the nitrogen oxides in the exhaust gas is used using the denitration catalyst, in order to heat off again. After the carbon dioxide is used for heat exchange, it is used for heating the combustion air 11 of the exhaust gas heating burner 5, so that the heat energy that has not been used so far can be effectively utilized. -9 - 201231147 According to the invention described in the third and sixth aspects of the patent application, the wet flue gas desulfurization device 7 is disposed in the exhaust gas flow path on the downstream side of the denitration device 6, and The SOx generated in the exhaust gas heating burner 5 can be removed, and if the SOx concentration at the inlet of the chimney 8 is 50 ppm, the desulfurization performance required in the flue gas desulfurization device 7 is about 95%'. It can reduce the desulphurization performance by about 3%. [Embodiment] An embodiment of the present invention will be described together with the drawings. Example 1 An exhaust gas treatment system according to the present invention is shown in Fig. 1. In the exhaust gas flow path of the granulation plant 1 for producing iron ore granulation used in the ironworks, the gas and gas heat exchanger 4 is installed in a wet flue gas desulfurization apparatus using a well-known limestone slurry or the like. On the upstream side of the seventh side, the wet flue gas desulfurization device 7 is placed on the downstream side of the denitration device 6 equipped with a well-known denitration catalyst. In the device described in Fig. 1 and the like, the device having the same function as that of the device shown in Fig. 7 is given the same number, and the description thereof will be omitted. Fig. 2 shows an example of the temperature balance around the gas and gas heat exchanger 4. The second (b) is a temperature balance when the denitration device 6 is disposed in the exhaust gas flow path on the downstream side of the exhaust gas desulfurization device 7 in the exhaust gas treatment system, but the exhaust gas desulfurization device 7 is discharged. The temperature of the exhaust gas is a saturated gas saturated with sulfur oxides and nitrogen oxides and drops to about 50 °C just before the gas and the -10-201231147 gas heat exchanger 4. The exhaust gas must be heated to about 350 ° C for the temperature necessary for the denitration treatment, and thus heating can be performed to combine the gas and gas heat exchanger 4 with the exhaust gas to heat the burner 5, but the temperature is maintained. Since the increase rate is large, the specification of the gas and gas heat exchanger 4 becomes large, or the exhaust gas is used to heat the fuel of the burner 5 in a large amount, and thus it is not economical. Further, since the exhaust gas is saturated with the sulfur oxide and the oxygen oxide, it is necessary to use a material having a corrosion resistance in the material of the gas and gas heat exchanger 4, and it is not economical. In the apparatus of the embodiment of the present invention shown in the second (a) diagram, the exhaust gas desulfurization device 7 is disposed in the exhaust gas flow path on the downstream side of the denitration device 6, and the denitration device 6 is directly The exhaust gas temperature at the inlet of the gas and gas heat exchanger 4 is 15 (TC), which not only reduces the specification of the gas and gas heat exchanger 4, but also reduces the amount of fuel used in the exhaust gas heating burner 5. Further, in the conventional exhaust gas treatment device, since the exhaust gas desulfurization device 7 is disposed in the discharge flow path immediately before the denitration device 6, the exhaust gas saturated with sulfur oxides and nitrogen oxides is used. It is introduced into the gas and gas heat exchanger 4. Therefore, in the gas and gas heat exchanger 4, it is necessary to consider a material having a selected corrosion resistance. In the apparatus of the present invention, the exhaust gas desulfurization device 7 is disposed in the degassing apparatus. In the exhaust gas flow path on the downstream side of the nitrate device 6, since the dried exhaust gas is introduced into the gas and gas heat exchanger 4, the material of the gas and gas heat exchanger 4 can be easily selected. 201231147 Again, In the apparatus of the present embodiment, the exhaust gas desulfurization device 7 is installed in the exhaust gas flow path on the downstream side of the denitration device 6, so that the S Ox generated in the exhaust gas heating burner 5 can be removed. A wide range of fuels, such as fuels containing sulfur fractions, can be used for the exhaust gas heating burner 5. The balance of the SOx concentration of the exhaust gas treatment system is shown in Fig. 3. The third (b) is the wet exhaust gas. An example of the balance of the SOx concentration when the desulfurization device 7 is disposed upstream of the denitration device 6. Since the exhaust gas flow path on the downstream side of the flue gas desulfurization device 7 is provided with the exhaust gas heating burner 5, it will contain The heavy oil of the sulfur fraction is used for the fuel of the exhaust gas heating burner 5, and the high concentration of SOx of about 1 200 ppm which is generated by burning the exhaust gas to heat the fuel of the burner 5 is not processed, but is introduced into the chimney 8. When the SOx concentration at the inlet of the smoke _ 8 is taken as 50 ppm, the required performance of the smog desulfurization device 7 must be determined in consideration of the SOx in the exhaust gas discharged from the exhaust gas heating burner 5. In this example, Smoke exhaust In the sulfur device 7, it takes about 98% of the desulfurization performance. In the apparatus of the present embodiment shown in Fig. 3(a), the exhaust gas desulfurization device 7 is disposed on the downstream side of the denitration device 6 In the road, it is also possible to remove the SOx generated in the exhaust gas heating burner 5, and when the SOx concentration at the inlet of the chimney 8 is 50 ppm, the desulfurization performance required in the flue gas desulfurization device 7 is about 9.5. In the present embodiment, the necessary desulfurization performance can be reduced by about 3%. In Fig. 4, the necessary desulfurization performance and the amount of the absorbing liquid circulating liquid in the limestone slurry of the flue gas desulfurization device 7 are shown. The exhaust gas introduced into the exhaust gas de--12-201231147 sulfur device 7 sprays the above-mentioned absorption liquid, performs a desulfurization reaction caused by gas-liquid contact, and stores the dropped absorption liquid in a reserve tank at a lower portion of the desulfurization device ( After not being shown), in order to circulate the exhaust gas for a plurality of times, it is possible to reduce the amount of the circulating liquid of the absorbent by about 20 by reducing the necessary desulfurization performance by 3% to 95% from 98%. %, can reduce power consumption or reduce cycle The number of receiving fluid pumped. Embodiment 2 Another embodiment of the present invention is shown in Fig. 5. In the exhaust gas treatment system shown in Fig. 5, the second gas and gas heat exchanger 9 is disposed on the downstream side of the denitration device 6 in the exhaust gas treatment system shown in Fig. 1 and is located upstream of the desulfurization device 7. An example of a side exhaust gas flow path. In the example shown in the fifth (a) diagram, the exhaust gas of the second gas disposed in the exhaust gas flow path on the downstream side of the denitration device 6 and the outlet of the gas heat exchanger 9 is about 200 ° C. The exhaust gas is introduced into the wet flue gas desulfurization device 7, cooled to a saturation temperature, and then discharged from the chimney 8. In the present embodiment, the second gas and gas heat exchanger 9 is disposed in the exhaust gas flow path immediately before the exhaust gas desulfurization device 7, and the heat energy recovered in the gas and gas heat exchanger 4 is flowed by the heat medium. The road 13 is supplied to the gas and gas reheater 10, and then used for preheating of the combustion air 11 of the exhaust gas heating burner 5, so that heat energy which has not been used up to now can be effectively utilized. As shown in Fig. 5(b), in addition to the gas and gas heat exchanger 4, the exhaust gas heating air heater 12 is used, and the combustion air 11 for discharging the -13-201231147 gas heating burner 5 can also be used. Preheating. Further, the exhaust gas is such that a large amount of evaporated water is discharged from the chimney 8 when the exhaust gas desulfurization device 7 is cooled. Fig. 6 shows the relationship between the inlet temperature of the flue gas desulfurization device 7 and the amount of evaporated water. The water was evaporated to about 150 t/h when it was introduced into the flue gas desulfurization device 7 at an exhaust gas temperature of 200 ° C, and it was evaporated to about 50 t/h when the exhaust gas temperature was 10 ° C. In the present embodiment, by arranging the gas and gas heat exchanger 4 directly in front of the wet flue gas desulfurization device 7, the evaporation can be reduced by lowering the temperature of the exhaust gas introduced into the flue gas desulfurization device 7. The amount of water is reduced to reduce the amount of water consumed in the exhaust gas treatment system. The present invention has a high utilization possibility as an apparatus which can efficiently process NOx and S Ox in a low-temperature exhaust gas discharged from a granulation manufacturing plant or the like. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a system as an exhaust gas treatment device of the present invention. Fig. 2 is a view showing the temperature balance of the exhaust gas treatment device of the present invention [Fig. 2 (a)] and the prior art [2 (b)]. Fig. 3 is a view showing the SOx concentration balance of the exhaust gas treatment device of the present invention [Fig. 3 (a)] and the prior art [Fig. 3 (b)]. Fig. 4 is a view showing desulfurization performance and Fig. 14 - 201231147 of the relationship between the amount of the effluent circulating liquid of the flue gas desulfurization apparatus, Fig. 5(a) and Fig. 5(b) are both added to the GGH heat recovery device as the exhaust gas treatment device of the present invention - The pattern of the heater. Fig. 6 is a view showing the relationship between the temperature of the inlet exhaust gas of the flue gas desulfurization apparatus and the amount of evaporated water. Figure 7 is a diagram showing the system of the exhaust gas treatment device. [Main component symbol description] 1 · Granulation plant 2: Electrical dust collector 3: Fan gas and gas heat exchanger 5 '·Exhaust gas heating burner 6 : Denitration device 7 : Wet flue gas desulfurization device 8 : Chimney 9 : Second gas and gas heat exchanger 1 : Reheater (reheater) 1 1 : Combustion air 12 : Exhaust gas heating Air Heater 1 3 : Thermal Media Flow Path-15-