1298780 (1) 九、發明說明 【發明所屬之技術領域】 本發明係有關一種從投入垃圾、產業廢棄物等的 燒物的機動爐排的下方導入一次空氣，在該機動爐排 的燃燒室進行一次燃燒之後，在該燃燒室的上方部位 二次燃燒的機動爐排式焚化爐，以及該機動爐排式焚 的運轉方法。 【先前技術】 機動爐排式焚化爐係具備交互配置固定段和活動 火格子而成的機動爐排，藉由油壓裝置使活動段來回 ’進行從送料斗投入的垃圾（被燃燒物）的攪拌和前 一邊在配置於該機動爐排的上游側的乾燥帶進行垃圾 燥，一邊在其次的主燃燒帶投入一次空氣一邊進行主 ’在最下游側的灰燼燃燒帶進行燃燒剩餘的灰燼燃燒 Φ化爐。 在這種機動爐排式焚化爐中，係提供一種使抽出 爐排上的燃燒室內的燃燒排氣的一部分的再循環氣體 再循環通路，回流到前述燃燒室內的二次燃燒部，與 空氣同時供給於燃燒的技術（例如，參照專利文獻1 本特許第3 5 827 1 0號公報）。 在專利文獻1所提供的技術中，抽出機動爐排上 燃燒室內的燃燒排氣的一部分做爲再循環氣體，並送 交換器，在該熱交換器中熱交換該再循環氣體和一次 被燃 上方 進行 化爐 段的. 移動 進， 的乾 燃燒 的焚 機動 通過 二次 的曰 方的 到熱 空氣 -5- (2) 1298780 及二次空氣，在預熱該一次空氣及二次空氣之同時，冷卻 該再循環氣體，藉由配置在前述熱交換器的後游側的風扇 ，將該已降溫的再循環氣體投入到比前述燃燒室內的二次 空氣供給口更上游側部位，使上游側的環境氣體設爲比二 次空氣供給口弱的還原性的環境氣體，將二次空氣供給後 的燃燒室內的全空氣比抑制爲1 .3左右，在完全燃燒未燃 氣或未燃物的同時使NOx降低。 • 然而，對於上述以往技術的機動爐排式焚化爐以及其 之運轉方法，具有如下的問題。 亦即，在前述以往技術中，抽出機動爐排上方的燃燒 室內的燃燒排氣的一部分做爲再循環氣體，並送到熱交換 器’藉由在該熱交換器與一次空氣及二次空氣熱交換，並 冷卻該再循環氣體之後，將該已降溫的再循環氣體配置於 前述熱交換器的後流側的風扇，爲了從燃燒室內的二次空 氣供給口投入至上游側部位，因此需要以該再循環氣體與 • 空氣（一次空氣以及二次空氣）熱交換，在使其降溫之後 送到風扇的熱交換器，將使燃燒排氣再循環系統的構造變 爲複雜，且機器數量變多而導致裝置成本上升。 又，前述風扇雖藉由前述熱交換器降溫，但由於原封 不動的將腐蝕成分多的燃燒排氣送入，因此容易腐鈾風扇 ’而導致該風扇的耐久性及壽命降低。 【發明內容】 [發明之揭示] -6 - (3) 1298780 本發明係有鑑於這種現狀而硏創者，其目的在 一種具備：藉由風扇使燃燒室內的燃燒排氣的一部 內回流作爲再循環氣體之再循環通路的機動爐排式 ，係不需要使該再循環氣體冷卻且降溫的熱交換器 化燃燒排氣再循環系統的構造，並使構成機器數及 本降低，更可抑制再循環氣體循環用的風扇之腐蝕 升該風扇的耐久性及壽命之機動爐排式焚化爐及其 φ 法。 爲了解決前述以往技術的問題，本發明之機動 焚化爐的運轉方法，係從投入被燃燒物的機動爐排 導入一次空氣，在該機動爐排上方的燃燒室內進行 燒之後，在該燃燒室的上方部位進行二次燃燒，並 述燃燒室內的燃燒排氣的一部分，藉由風扇往爐內 循環通路使之再循環，而作爲再循環氣體時，於前 環通路的前述風扇的上游部位中，於再循環氣體混 •，使該混合氣體回流至前述燃燒室內。在此，係於 循環通路的前述風扇的上游部位，設置用來計測前 氣體的溫度的計測器，以前述混合氣體的溫度成爲 以下的方式，控制前述再循環氣體和空氣的比例。 又，本發明之機動爐排式焚化爐的運轉方法， 入被燃燒物的機動爐排的下方導入一次空氣，在該 排上方的燃燒室內進行一次燃燒之後，在該燃燒室 部位進行二次燃燒，並且使前述燃燒室內的燃燒排 部分作爲再循環氣體，而藉由風扇往爐內通過再循 於提供 分往爐 焚化爐 ，可簡 裝置成 ，可提 運轉方 爐排式 的下方 一次燃 且使前 通過再 述再循 合空氣 前述再 述混合 400 °C 係從投 機動爐 的上方 氣的一 環通路 (4) 1298780 使之再循環時’在前述再循環通路的前述風扇上游部位中 ’於則述再循環氣體混合空氣，使該混合氣體回流至前述 燃燒室內’使用供給至前述機動爐排的燃燒用的一次空氣 或一次空氣中任一方做爲與前述再循環氣體混合的空氣。 又’用來實施前述運轉方法的裝置的發明，係具備有 :從投入被燃燒物的機動爐排的下方導入一次空氣，在該 機動爐排上方的燃燒室，使用從一次空氣供給手段所供給 Φ的一次空氣，進行一次燃燒之後，在該燃燒室的上方部位 進行二次燃燒，並且使前述燃燒室內的燃燒排氣體的一部 分往爐內’作爲再循環氣體回流的再循環通路；以及將該 再循環氣體壓送到前述燃燒室內的風扇的機動爐排式焚化 爐，係於前述再循環通路的前述風扇的上游部位，連接用 來使外部空氣、或供給至前述機動爐排之燃燒用的一次空 氣、或二次空氣中任一方流通的空氣通路，於前述再循環 氣體混合空氣，並導入至前述風扇而構成。 • 再者，用來實施前述運轉方法的裝置的發明，係具備 有：從投入被燃燒物的機動爐排的下方導入一次空氣的一 次空氣供給通路；在該機動爐排上方，藉由前述一次空氣 進行一次燃燒的燃燒室；在該燃燒室的上方部位進行二次 燃燒的二次燃燒室；使前述燃燒室內的燃燒排氣的一部分 往爐內作爲再循環氣體回流的再循環通路；以及將該再循 環氣體壓送到前述燃燒室內的風扇的機動爐排式焚化爐’ 具備：與前述再循環通路的前述風扇的上游部位連接的空 氣通路；與前述再循環氣體混合並應導入至前述風扇，於 -8- (5) 1298780 前述空氣通路供給外部空氣、前述一次空氣或二次空氣中 任一種的空氣供給手段。 又’本發明除了前述機動爐排式焚化爐的運轉方法之 外，係具有如下的雨種運轉方法。 (1 ) 一種機動爐排式焚化爐的運轉方法，係從投入 被燃燒物的機動爐排的下方導入一次空氣，在該機動爐排 上方的燃燒室內進行一次燃燒之後，在該燃燒室的上方部 # 位進行二次燃燒，並且使前述燃燒室內的燃燒排氣的一部 分，藉由風扇往爐內作爲再循環氣體通過再循環通路使之 再循環時，在前述再循環通.路的前述風扇上游部位中，於 前述再循環氣體混合空氣，使該混合氣體回流至前述燃燒 室內，係於前述再循環通路的前述風扇的上游部位具備除 塵裝置，在前述再循環通路的前述除麈裝置和風扇之間的 部位上，於前述再循環氣體混合空氣。 (2 ) —種機動爐排式焚化爐的運轉方法，係從投入 # 被燃燒物的機動爐排的下方導入一次空氣，在該機動爐排 上方的燃燒室內進行一次燃燒之後，在該燃燒室的上方部 位進行二次燃燒，並且使前述燃燒室內的燃燒排氣的一部 分，藉由風扇往爐內作爲再循環氣體通過再循環通路使之 再循環時，在前述再循環通路的前述風扇上游部位中，於 前述再循環氣體混合空氣，使該混合氣體回流至前述燃燒 室內，係於前述再循環通路的前述風扇的上游部位具備除 塵裝置，在前述再循環通路的前述除塵裝置的上游部位， 於前述再循環氣體混合空氣。 -9 - (6) 1298780 再者，本發明係除了前述機動爐排式焚化爐的運轉方 法之外，另包含下一個運轉方法。 (3 )將混合前述空氣的再循環氣體，導入到前述燃 燒室的上方部位的燃燒排氣流動方向的複數處的運轉方法 〇 根據本發明，將從機動爐排上方的燃燒室內抽出的燃 燒排氣的一部分做爲再循環氣體，藉由風扇通過再循環通 φ 路回流到燃燒室內，前述再循環通路的前述風扇的上游部 位中，最好於前述再循環氣體直接混合供給至機動爐排的 燃燒用的一次空氣或二次空氣中任一方所構成的空氣（亦 可爲外部空氣），且導入到再循環氣體回流用的風扇，藉 由該風扇使由該混合氣體所構成的再循環氣體回流至燃燒 室內，因此藉由空氣使燃燒排氣降溫，並且藉由與空氣的 混合稀釋燃燒排氣，而可導入至風扇。 藉此，不需要用來冷卻並降溫以往技術的再循環氣體 • 的熱交換器，而可簡化燃燒排氣再循環系統的構造，並且 可降低構成機器數量，而使焚化設備的裝置成本降低。 又，藉著於再循環氣體混合由一次空氣或二次空氣中 任一方所構成的空氣，而不需設置新的風扇或槽，而使構 成更簡略。 又，在燃燒室的二次燃燒區域中，藉由前述再循環氣 體或二次空氣的運動量促進混合，謀求完全燃燒的達成及 有害物質的降低化，因此，要求提高保持前述再循環氣體 或二次空氣的供給壓力，而以高旋轉且大的離心力使前述 -10- (7) 1298780 再循環氣體回流用的風扇作用。 因此，於該風扇有大的離心應力且再循環氣體的溫度 高時，大的熱應力重疊，藉由在高應力狀態下且由燃燒排 氣所構成的再循環氣體，成爲高腐蝕環境。 然而，根據本發明，導入至前述再循環氣體回流用的 風扇的再循環氣體，係藉由低溫的空氣予以冷卻並且降溫 ，又藉由該空氣加以稀釋，使燃燒排氣濃度降低，再者， • 藉由前述冷卻固化排氣中的腐鈾成分即鹽類，而使腐蝕成 分降低的再循環氣體，因此使風扇的溫度降低，使該風扇 的熱應力縮小，並且如前所述，藉由將降低腐鈾成分的再 循環氣體導入到風扇，可抑制風扇的腐蝕，藉此不需使用 高價的耐熱材料，而可獲得低成本化的風扇，可以維持所 需的耐久性及壽命。 特別是在設置於風扇的上游部位的溫度計測器監視混 合空氣溫度，其混合空氣溫度成爲4 0 0 °C以下，藉著控制 #前述再循環氣體和空氣的比例，於長時間運用該風扇成爲 足夠的低熱應力，再者，於再循環氣體的高溫狀態下，爲 氣體狀態的鈉鹽等的低融點物質的融點大致上爲7 0 0 °C， 因此可完全固化前述低融點物質，而可避免低融點物質往 該風扇的附著或腐蝕。 又，根據本發明，如前述（1 )所示，於藉由設置在 前述再循環通路的風扇上游部位的旋風器除塵裝置，除去 氣體中的塵類而被清淨化的再循環氣體，藉由前述的空氣 的混合進行降溫及防止腐蝕處理，因此可除去風扇的劣化 -11 - (8) 1298780 成分，而可將更乾淨的再循環氣體導入到風扇，更加提升 風扇的耐久性及壽命。 再者，根據本發明’於藉由前述空氣的混合進行降溫 及腐蝕防止處理而成爲低溫的再循環氣體，如前述（2) 所示’藉由設置在再循環通路的風扇的上游部位的除塵裝 置’除去氣體中的塵類’因此在再循環氣體的高溫狀態下 ’藉由將再循環氣體設爲低溫，使氣體狀態的鈉鹽等的低 φ 融點物質固化，在除塵裝置使其可從氣體中進行分離、除 去處理，可完全的除去前述低融點物質。 又，根據本發明，如前述（3 )所示，將混入空氣的 再循環氣體導入到沿著燃燒室的上方部位的燃燒排氣流動 方向的複數處’促進爐內的再循環氣體和爐內氣體的混合 ’可促進二次燃燒室的未燃燒氣體的燃燒。 【實施方式】 [第1實施形態] 第1圖係本發明第1實施形態的機動爐排式焚化爐的 構成圖。 在第1圖中，1係投入垃圾或產業廢棄物等的被燃燒 物的垃圾送料斗。2係機動爐排式焚化爐。該機動爐排式 焚化爐2係敷設有：於從垃圾送料口 1的投入口的爐內底 部’主要構成乾燥帶的乾燥帶機動爐排2 1 ;主要構成燃燥 帶的主燃燒帶機動爐排22 ;以及主要構成灰燼燃燒帶的灰 燼燃燒帶機動爐排23。乾燥帶機動爐排2 1係位於最上游 -12· (9) 1298780 側，主燃燒帶機動爐排22位於乾燥帶機動爐排2 1的下游 側，灰燼燃燒帶機動爐排23係在主燃燒帶機動爐排22的 下游而位於最下游側。在此，主燃燒帶係指在垃圾層上使 火燄上升而燃燒的區域。 前述各機動爐排21、22、23，係具備有配設於固定火 格子之間的移動火格子，藉由該移動火格子的來回運動， 在投入垃圾（被燃燒物）之後，以機動爐排21使該垃圾 • 乾燥，以機動爐排22進行主燃燒，最後在機動爐排23進 行灰燼燃燒。然後，在該實施形態中，前述主燃燒帶機動 爐排22雖然爲3個，但亦可設置1個或設置複數個。8爲 灰捕集槽。 又，前述機動爐排21、22、23的上方設置有一次燃 燒室3，更於其上方設置有二次燃燒室4。 19a、19b係面對二次燃燒室4而設置的再循環氣體吹 出噴嘴。又，81係與二次燃燒室4的排氣出口連接的鍋爐 •。 於乾燥帶機動爐排2 1、燃燒帶機動爐排22及灰燼燃 燒帶機動爐排23，配設有分別於下部的風箱開口的一次空 氣管5 1、5 2 ( 3個）、5 3，以使從該一次空氣管供給一次 空氣。6爲一次空氣供給用的風扇，5爲分別連接該風扇6 和一次空氣管51、52(3個）、53的一次空氣主管，從風 扇6被壓送的一次空氣，從一次空氣主管5分配到一次空 氣管51、52、53。一次空氣管51、52、53係設置有分別 開關此等的開關閥5 4、5 5、5 6。又，於一次空氣主管5設 -13- (10) 1298780 置有對此進行開關之開關閥7。 40爲將一次燃燒室3內（亦可在二次燃燒室4 燃燒排氣的一部分抽出做爲再循環氣體的再循環氣 口，從該再循環氣體抽出口 40抽出的再循環氣體 再循環通路16而導入至再循環風扇13的吸入通路 此，再循環氣體抽出口 40和吸入通路3 1經由再循 1 6而連接，在吸入通路3 1設置有用來開關再循環| 鲁入口的開關閥013。 3 〇係從一次空氣主管5分支，與再循環風扇1 游部位及與吸入通路31連接的混入空氣通路，30a 關閉混入空氣通路3 0的開關閥，當打開該開關閥 ，來自一次空氣主管5的一次空氣通過混入空氣通S 投入到吸入通路31的再循環風扇13的入口，於前 環氣體混合一次空氣並導入至再循環風扇13。 60係用來計測再循環氣體和空氣的混合氣體的 • 溫度計測器，61係用來控制開關閥7、開關閥〇 1 3 閥3 0a之開關的控制裝置。該控制裝置6 1係以溫 器60所計測的溫度成爲設定溫度，以自動的調整開 、開關閥〇 1 3、開關閥3 0a的開度之方式設定，藉 整在混入空氣通路30流動的一次空氣的流量，而 入至再循環風扇1 3的再循環氣體的燃燒排氣和一 的混合比例而構成。 然後，藉由再循環風扇1 3壓送到再循環通路1 次空氣混合後的再循環氣體，係在再循環通路1 7、 內）的 體抽出 ，通過 3 1。因 環通路 臥扇1 3 3的上 係打開 3 0a時 咨30 > 述再循 溫度之 、開關 度計測 關閥7 此，調 調整導 次空氣 5的一 18分 -14- (11) 1298780 支，而分別送入到再循環氣體吹出噴嘴19a、19b，從再循 環氣體吹出噴嘴19a、19b噴出到二次燃燒室4內。又， 於再循環通路1 7內設置有用來開關此的開關閥3 3，於再 循環通路1 8內設置有用來開關此的開關閥32。 此外，在該實施形態中，雖然於再循環風扇1 3的入 口的再循環氣體混合一次空氣，而導入到再循環風扇13, 但取代該一次空氣，於再循環氣體混合噴出到二次燃燒室 • 4內的二次空氣或來自外部的空氣，而導入到再循環風扇 13之構成亦可。 在本發明的第1實施形態的機動爐排式焚化爐2及其 運轉方法，將從機動爐排上方的燃燒室內（一次燃燒室3 或二次燃燒室4 )通過再循環氣體抽出口 40而抽出的燃燒 排氣的一部分做爲再循環氣體，經由再循環風扇13等分 別送出到再循環氣體吹出噴嘴1 9a、1 9b，從該再循環氣體 吹出噴嘴19a、19b噴出到二次燃燒室4內，並且在構成 # 再循環氣體通路的吸入通路3 1的再循環風扇1 3的上游部 位中，藉由混入空氣通路3 0於前述再循環氣體直接混合 燃燒用的一次空氣（或二次空氣或來自外部的空氣），並 導入至再循環風扇13,使該混合空氣所構成的再循環氣體 藉由再循環風扇13，回流至前述燃燒室內而構成，因此藉 由一次空氣使燃燒排氣降溫，並且藉由與該一次空氣的混 合，稀釋燃燒排氣而導入至再循環風扇13。 藉此，不需要如以往技術用來冷卻並降溫從燃燒室內 抽出的燃燒排氣（再循環氣體）的熱交換器，使燃燒排氣 -15- (12) 1298780 再循環系統的構造簡化，並降低構成機器數量，使垃圾焚 化設備的裝置成本降低。 又，由於在再循環氣體混合由一次空氣構成的空氣， 因此不需要設置新的空氣混合用的風扇或槽，而更可簡化 其構成。 又，在該機動爐排式焚化爐中，於前述燃燒室的二次 燃燒區域即二次燃燒室4中，藉由前述再循環氣體或二次 φ 空氣的運動量促進混合，而謀求完全燃燒的達成及有害物 質的降低，其結果，由於要求保持前述再循環氣體或二次 空氣的供給壓力較高，因此，前述再循環氣體回流用的再 循環風扇1 3，以高旋轉且大的離心力作用。 因此，再循環風扇13在大的離心應力且再循環氣體 的溫度高時，重疊大的熱應力，雖然因在高應力狀態下且 由燃燒排氣所構成的再循環氣體而成爲高腐蝕環境，但根 據本發明的第1實施形態，於再循環風扇1 3藉由低溫的 • 一次空氣加以冷卻並降溫，而且藉由該一次空氣加以稀釋 ’並使燃燒排氣濃度降低，藉由前述冷卻來固化排氣中的 腐蝕成分及鹽類，而導入降低腐蝕成分的再循環氣體。 因而，根據本發明第1實施形態的機動爐排式焚化爐 2及其運轉方法，使再循環風扇1 3的溫度降低，使再循環 風扇1 3的熱應力變小，如前所述，將降低腐蝕成分的再 循環氣體導入至再循環風扇13，可抑制再循環風扇13的 腐蝕。藉此，不需使用高價的耐熱材料，而獲得低成本的 再循環風扇1 3 ’可維持需要的耐久性及壽命。 •16- (13) 1298780 特別是，以設置於再循環風扇1 3的上游部位的溫度 計測器6 0，監視混合氣體溫度，藉著控制前述再循環氣體 和空氣的比例，而使該混合氣體溫度成爲400°C以下，在 長期間運用該再循環風扇13而成爲足夠的低熱應力，更 於再循環氣體的高溫狀態下，成爲氣體狀態的鈉鹽等低融 點物質的融點爲槪略7 0 0 °C，因此可完全固化前述低融點 物質，可避免低融點物質附著於該再循環風扇1 3而腐蝕 •。 具體說明該作用。在一般運轉狀態下，控制裝置6 1 的混合氣體溫度設定爲40(TC以下，以溫度計測器60所計 測的溫度成爲設定溫度以下，而設定有開關閥7、開關閥 013、開關閥30a。在該狀態下，對於燃燒沒有幫助的一次 燃燒室3的爐內氣體的一部分與混合空氣混合，由於做爲 二次空氣再投入到爐內，因此實現削減新投入的二次空氣 量的低空氣比運轉。再者，由於在二次空氣包含低氧濃度 # 的爐內氣體，因此亦可實現緩慢燃燒之低NOx運轉的狀 態。當再循環氣體溫度變高，在溫度計測器60所計測的 混合氣體溫度超越控制裝置6 1的設定溫度時，打開開關 閥3 0a而增多空氣量，藉著關閉開關閥013減少再循環氣 體量，或藉著採用此兩個手段，使混合氣體溫度下降。此 時，藉著打開開關閥3 0a，由於一次空氣減少，因此藉著 打開開關閥7，將一次空氣量保持在一定。藉由該作用’ 可經常的將混合氣體溫度保持爲40(TC以下，藉此，可長 期的運轉該再循環風扇13，且可避免低融點物質附著、腐 -17- (14) 1298780 蝕再循環風扇1 3。 [第2實施形態] 第2圖係本發明的第2實施形態的機動爐排式焚化爐 的構成圖。 在該第2實施形態中，附加於前述第1實施形態的構 成，於再循環通路16設置旋風器12做爲除塵裝置的一例 # ，於連接該旋風器1 2的出口和再循環風扇1 3的吸入通路 1 2a，連接有從一次空氣主管5分支的混入空氣通路3 0。 亦即，在本發明的第2實施形態中，將由從再循環通 路16導入至旋風器12的燃燒排氣構成的再循環氣體，在 旋風器12以周知的手段除去該再循環氣體中的麈類之後 ，將來自混入空氣通路3 0的一次空氣與該再循環氣體混 合，導入至再循環風扇13。 其他的構成與前述第1實施形態（第1圖）相同，與 • 此相同的構件係附加相同的符號並省略說明。 因而，根據本發明的第2實施形態，於藉由設置於再 循環通路1 5的再循環風扇1 3的上游部位的旋風器1 2，除 去氣體中的塵類而清淨化的再循環氣體中，混合與前述第 1實施形態相同來自混入空氣通路30的一次空氣，而進行 該再循環氣體的降溫及腐蝕防止處理，因此可除去再循環 風扇1 3的劣化成分，而更可將已清淨化的再循環氣體導 入至再循環風扇13，更提升再循環風扇13的耐久性及壽 命0 -18- (15) 1298780 [第3實施形態] 第3圖係本發明的第3實施形態的機動爐排式焚化爐 的構成圖。 在該貫施形態中，附加於前述第1實施形態’於再循 環通路16設置旋風器12，該旋風器12的入口通路14與 再循環通路1 6連接，於該入口通路1 4連接有從一次空氣 φ 主管5分支的混入空氣通路30。 亦即，在本發明的第3實施形態中，從再循環通路1 6 導入至旋風器12之前的再循環氣體中，混合來.自混入空 氣通路30的一次空氣之後，導入至旋風器12，在旋風器 12以周知的手段除去該再循環氣體中的塵類，而導入至再 循環風扇1 3。 其他的構成與前述第1實施形態（第1圖）或第2實 施形態（第2圖）相同，與此相同的構件係附加相同的符 _號並省略說明。 因而，根據本發明的第3實施形態，藉由來自前述混 入空氣通路3 0的一次空氣的混合而降溫，並進行腐飩防 止處理，於成爲低溫的再循環氣體，藉由設置於再循環通 路1 5的再循環風扇1 3的上游部位的旋風器1 2，除去氣體 中的塵類之後，將再循環氣體導入至再循環風扇13，因此 在再循環氣體的高溫狀態下，藉由前述一次空氣的混合， 將再循環氣體設爲低溫，使氣體狀態的鈉鹽等低融點物質 固化，以旋風器12使該固體從氣體中分離而除去處理， -19- (16) 1298780 可完全除去低融點物質。 [第4實施形態] 第4圖係本發明的第4實施形態的機動爐排式焚化爐 的構成圖。 在該第4貫施形_中，附加於前述第1實施形態，於 再循環通路16設置旋風器12，該旋風器12的入口通路 # 14與再循環通路16連接，於該入口通路14連接有從一次 空氣主管5分支的混入空氣通路3〇之構成，與前述第3 實施形態相同。 除此以外，在該第4實施形態中，面對二次燃燒室4 ’於再循環氣體吹出噴嘴19a、丨9b的上游側追設再循環 氣體吹出噴嘴19c、19d，並與再循環通路17、18連接， 混合來自再循環風扇13的一次空氣的再循環氣體，從再 循環氣體吹出噴嘴19a、19b以及再循環氣體吹出噴嘴19c ® 、1 9d的2段位置，噴出到二次燃燒室4內而構成。 此外’前述再循環氣體吹出噴嘴，亦可設置3段以上 〇 又’本發明的第4實施形態，係如前述第1實施形態 ’亦可應用於不具有除麈裝置的機動爐排式焚化爐。 其他的構成與前述第〗實施形態（第i圖）或第2實 方挺0態、（第2圖）相同，與此相同的構件附加相同的符號 ，並省略說明。 医I而’根據本發明的第4實施形態，如前述第3實施 -20- (17) 1298780 形態，使混合一次空氣的再循環氣體，從沿著二次燃燒室 4的燃燒排氣流動方向的複數處噴出到二次燃燒室4，而 促進二次燃燒室4內的再循環氣體和爐內氣體的混合，可 促進二次燃燒室4的未燃氣體的燃燒。 以上’雖說明本發明的實施形態，但本發明不限定於 上述的實施形態，可依據本發明的技術思想，進行各種變 形及變更。 【圖式簡單說明】 第1圖係本發明的第1實施形態的機動爐排式焚化爐 的構成圖。 第2圖係本發明的第2實施形態的機動爐排式焚化爐 的構成圖。 第3圖係本發明的第3實施形態的機動爐排式焚化爐 的構成圖。 • 第4圖係本發明的第4實施形態的機動爐排式焚化爐 的構成圖。 【主要元件符號說明】 1 :垃圾送料斗 2 :機動爐排式焚化爐 3 : —次燃燒室 4 :二次燃燒室 5 : —次空氣主管 -21 - (18) 1298780 6 :風扇 7 :開關閥 8 :灰補集槽 12 :旋風器 12a :吸入通路 1 3 :再循環風扇 0 1 3 :開關閥 φ 14 :入口通路 15、16、17、18:再循環通路 19a、19b、19c、19d:再循環氣體吹出噴嘴 2 1 :乾燥帶機動爐排 22 :主燃燒帶機動爐排 23 :燃燒帶機動爐排 3 0 :混入空氣通路 3〇a :開關閥 馨 3 1 :吸入通路 32、33 :開關閥 40 :再循環氣體抽出口 51、52、53: —次空氣管 5 4、5 5、5 6 :開關閥 60 :溫度計測器 6 1 :控制裝置 81 :鍋爐 -22-BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primary air introduced from a lower side of a motorized grate that is put into waste, industrial waste, or the like, in a combustion chamber of the mobile grate. After a primary combustion, a motorized grate-type incinerator that is secondaryly burned in the upper portion of the combustion chamber, and a method of operating the mobile grate-type incineration. [Prior Art] The mobile grate incinerator has a mobile grate which is formed by alternately configuring a fixed section and a movable fire lattice, and the hydraulic section is used to make the movable section back and forth 'to carry the garbage (burned matter) from the hopper. Stirring and the front side of the drying belt disposed on the upstream side of the motorized grate are garbage-dried, while the second main combustion belt is supplied with air, and the main ash burning belt on the most downstream side is burned for remaining ash combustion. Furnace. In such a mobile grate incinerator, a recirculation gas recirculation passage for extracting a part of combustion exhaust gas in a combustion chamber on a grate is returned to a secondary combustion portion in the combustion chamber, simultaneously with air A technique of supplying combustion (for example, refer to Patent Document 1 of the Japanese Patent No. 3 5 827 1 0). In the technique disclosed in Patent Document 1, a part of the combustion exhaust gas in the combustion chamber on the motorized grate is extracted as a recirculation gas, and is sent to an exchanger in which the recirculation gas is heat-exchanged and once ignited. The upper part of the furnace section is moved in, and the dry burning of the incineration maneuver is passed through the secondary air to the hot air -5 - (2) 1298780 and the secondary air, while preheating the primary air and the secondary air Cooling the recirculating gas, and placing the cooled recirculated gas into the upstream side of the secondary air supply port in the combustion chamber by the fan disposed on the rear side of the heat exchanger to make the upstream side The ambient gas is a reducing atmosphere that is weaker than the secondary air supply port, and the total air ratio in the combustion chamber after the secondary air is supplied is suppressed to about 1.3, and the unburned or unburned material is completely burned. At the same time, NOx is lowered. • However, the above-described prior art motorized grate incinerator and its operation method have the following problems. That is, in the foregoing prior art, a part of the combustion exhaust gas in the combustion chamber above the motorized grate is extracted as a recirculation gas and sent to the heat exchanger 'by the heat exchanger and the primary air and the secondary air After heat exchange and cooling of the recycle gas, the fan having the cooled recirculated gas disposed on the downstream side of the heat exchanger is required to be supplied to the upstream side portion from the secondary air supply port in the combustion chamber. The heat exchange between the recirculating gas and the air (primary air and secondary air), after being cooled to the heat exchanger of the fan, complicates the structure of the combustion exhaust gas recirculation system, and the number of machines becomes variable. More and more, the cost of the device rises. Further, although the fan is cooled by the heat exchanger, since the combustion exhaust gas having a large amount of corrosive components is supplied as it is, the uranium fan is easily rotted, and the durability and life of the fan are lowered. [Disclosure of the Invention] [Disclosure of the Invention] -6 - (3) 1298780 The present invention has been made in view of such a situation, and an object thereof is to provide an internal recirculation of a combustion exhaust gas in a combustion chamber by a fan. The motorized grate type of the recirculation passage of the recirculating gas is a structure of a heat exchanger-based combustion exhaust gas recirculation system that does not require cooling and cooling of the recirculation gas, and reduces the number of constituent machines and the number of components, thereby suppressing The motorized grate incinerator and its φ method for the corrosion of the recirculating gas circulating fan to increase the durability and life of the fan. In order to solve the above-mentioned problems of the prior art, the operation method of the motorized incinerator according to the present invention is to introduce primary air from a motorized grate in which the object to be burned is introduced, and to burn in the combustion chamber above the motorized grate, in the combustion chamber. The upper portion is subjected to secondary combustion, and a part of the combustion exhaust gas in the combustion chamber is recirculated by the fan to the circulation passage in the furnace, and in the upstream portion of the fan of the front ring passage as the recirculation gas, The mixed gas is returned to the combustion chamber by mixing with the recycle gas. Here, a meter for measuring the temperature of the pre-gas is provided in the upstream portion of the fan in the circulation passage, and the ratio of the recirculated gas to the air is controlled such that the temperature of the mixed gas is as follows. Further, in the operation method of the motorized grate type incinerator according to the present invention, primary air is introduced into the lower side of the motorized grate of the object to be combusted, and once combustion is performed in the combustion chamber above the row, secondary combustion is performed in the combustion chamber portion. And the combustion exhaust portion in the combustion chamber is used as a recirculating gas, and the fan is passed through the furnace to provide a separate furnace incinerator, which can be simplified, and can be used to lower the lower side of the running grate type. By repeating the above-mentioned recirculation air, the above-mentioned mixing 400 ° C is recirculated from a loop passage (4) 1298780 of the upper gas of the motorized furnace, 'in the upstream portion of the aforementioned fan of the aforementioned recirculation passage' The recirculating gas mixed air is returned to the combustion chamber to use either one of primary air or primary air for combustion supplied to the motorized grate as air mixed with the recirculating gas. Further, the invention of the apparatus for carrying out the above-described operation method is characterized in that primary air is introduced from below the motorized grate in which the object to be burned is introduced, and the combustion chamber above the motorized grate is supplied from the primary air supply means. After the primary air of Φ is subjected to primary combustion, secondary combustion is performed at an upper portion of the combustion chamber, and a part of the combustion exhaust gas in the combustion chamber is returned to the furnace as a recirculation passage for recirculating gas return; a motorized grate type incinerator in which a recirculating gas is pressure-fed to a fan in the combustion chamber, and is connected to an upstream portion of the fan of the recirculation passage to connect external air or to supply combustion to the motorized grate An air passage that flows through one of the primary air or the secondary air is mixed with the recirculated gas and introduced into the fan. Further, the invention of the apparatus for carrying out the above-described operation method includes a primary air supply passage for introducing primary air from below the motorized grate in which the object to be burned is introduced, and the above-mentioned one of the above-mentioned motorized grate a combustion chamber in which the air is once combusted; a secondary combustion chamber that performs secondary combustion at a portion above the combustion chamber; a recirculation passage that returns a portion of the combustion exhaust gas in the combustion chamber to the furnace as a recirculation gas; and The motorized grate type incinerator of the fan that is recirculated to the combustion chamber in the combustion chamber includes: an air passage connected to an upstream portion of the fan of the recirculation passage; and is mixed with the recirculating gas and introduced to the fan , -8-(5) 1298780 The air passage supplies an air supply means for any of the outside air, the primary air or the secondary air. Further, the present invention has the following rain species operation method in addition to the operation method of the above-described motorized grate type incinerator. (1) A method of operating a mobile grate incinerator, which introduces primary air from below a motorized grate to which an incineration object is introduced, and performs combustion once in a combustion chamber above the motorized grate, above the combustion chamber The portion # is subjected to secondary combustion, and a part of the combustion exhaust gas in the combustion chamber is recirculated through the recirculation passage as a recirculating gas in the furnace, and the aforementioned fan of the recirculation passage In the upstream portion, air is mixed with the recirculating gas, and the mixed gas is returned to the combustion chamber, and a dust removing device is provided in an upstream portion of the fan in the recirculation passage, and the quenching device and the fan in the recirculation passage are provided. At the location between them, air is mixed with the aforementioned recycle gas. (2) A method for operating a mobile grate incinerator, which introduces primary air from below a motorized grate that is put into the incineration, and after combustion in the combustion chamber above the motorized grate, in the combustion chamber The upper portion is subjected to secondary combustion, and a part of the combustion exhaust gas in the combustion chamber is recirculated through the recirculation passage as a recirculating gas in the furnace, and the upstream portion of the fan in the recirculation passage Mixing air with the recirculating gas to return the mixed gas to the combustion chamber, and providing a dust removing device at an upstream portion of the fan in the recirculation passage, and upstream of the dust removing device in the recirculation passage The aforementioned recycle gas mixes air. -9 - (6) 1298780 Furthermore, the present invention includes the next operation method in addition to the operation method of the aforementioned motorized grate type incinerator. (3) an operation method of introducing a recirculating gas in which the air is mixed into a plurality of combustion exhaust gas flow directions in an upper portion of the combustion chamber, and a combustion row extracted from a combustion chamber above the motorized grate according to the present invention a part of the gas is used as a recirculating gas, and is returned to the combustion chamber by the fan through the recirculation passage φ. In the upstream portion of the fan of the recirculation passage, the recirculated gas is preferably directly mixed and supplied to the motorized grate. An air made of one of primary air or secondary air for combustion (may also be external air), and introduced into a fan for recirculating the return gas, by which the recycle gas composed of the mixed gas is used The gas is returned to the combustion chamber, so that the combustion exhaust gas is cooled by the air, and the exhaust gas is diluted by mixing with the air to be introduced into the fan. Thereby, a heat exchanger for cooling and lowering the recirculation gas of the prior art is not required, and the configuration of the combustion exhaust gas recirculation system can be simplified, and the number of constituent machines can be reduced, and the apparatus cost of the incineration plant can be reduced. Further, by mixing the air composed of either the primary air or the secondary air with the recirculating gas, it is not necessary to provide a new fan or groove, and the configuration is made simpler. Further, in the secondary combustion region of the combustion chamber, the amount of movement of the recirculating gas or the secondary air is promoted to promote the completion of complete combustion and the reduction of harmful substances. Therefore, it is required to improve the maintenance of the above-mentioned recycle gas or two. The supply pressure of the secondary air acts as a fan for the reflux of the above-mentioned-10-(7) 1298780 recycle gas with high rotation and large centrifugal force. Therefore, when the fan has large centrifugal stress and the temperature of the recirculating gas is high, large thermal stresses overlap, and the recirculating gas composed of combustion exhaust gas in a high stress state becomes a highly corrosive environment. According to the present invention, however, the recirculation gas introduced into the fan for recirculating the recycle gas is cooled and cooled by the low-temperature air, and diluted by the air to lower the combustion exhaust concentration. • by the above-described cooling and solidification of the uranium component in the exhaust gas, that is, the salt, to reduce the corrosion gas of the recycled component, thereby lowering the temperature of the fan and reducing the thermal stress of the fan, and as described above, By introducing the recirculating gas for reducing the uranium component into the fan, the corrosion of the fan can be suppressed, and a low-cost fan can be obtained without using a high-priced heat-resistant material, and the required durability and life can be maintained. In particular, the temperature measuring device installed in the upstream portion of the fan monitors the temperature of the mixed air, and the temperature of the mixed air becomes below 400 ° C. By controlling the ratio of the recycled gas and the air, the fan is used for a long time. Sufficient low thermal stress. Further, in the high temperature state of the recirculating gas, the melting point of the low melting point substance such as the sodium salt in the gaseous state is substantially 700 ° C, so that the low melting point substance can be completely cured. The adhesion or corrosion of the low melting point substance to the fan can be avoided. Further, according to the present invention, as shown in the above (1), the cyclone dust removing device provided at the upstream portion of the fan of the recirculation passage removes the dust in the gas and is purified by the recirculation gas. The above-mentioned mixing of the air is performed to lower the temperature and prevent the corrosion treatment, so that the deterioration of the fan -11 - (8) 1298780 can be removed, and a cleaner recirculating gas can be introduced into the fan, thereby further improving the durability and life of the fan. Further, according to the present invention, the recirculating gas which is cooled at a low temperature by the mixing of the air and the corrosion prevention treatment is as shown in the above (2), and the dust is removed from the upstream portion of the fan provided in the recirculation passage. The device 'removes the dust in the gas', so in the high-temperature state of the recirculating gas, 'the low-φ melting point substance such as the sodium salt in the gaseous state is solidified by setting the recirculating gas to a low temperature, and the dust removing device can be used in the dust removing device. The separation and removal treatment from the gas completely removes the low melting point substance. Further, according to the present invention, as shown in the above (3), the recirculated gas mixed with air is introduced into a plurality of portions of the combustion exhaust gas flow direction along the upper portion of the combustion chamber to promote the recirculation gas in the furnace and the furnace. The mixing of gases 'can promote the combustion of unburned gases in the secondary combustion chamber. [Embodiment] FIG. 1 is a configuration diagram of a motorized grate type incinerator according to a first embodiment of the present invention. In the first drawing, 1 is a garbage hopper that is used to burn objects such as garbage or industrial waste. 2 series mobile grate incinerator. The mobile grate incinerator 2 is provided with: a drying belt motorized grate 2 which mainly constitutes a drying belt from the bottom of the inlet of the garbage feeding port 1; a main combustion belt motorized furnace mainly constituting the burning belt Row 22; and the ash burning belt motorized grate 23 which mainly constitutes the ash burning zone. The drying belt motorized grate 2 1 is located on the most upstream -12· (9) 1298780 side, the main combustion belt motorized grate 22 is located on the downstream side of the drying belt motorized grate 21, and the ash burning belt motorized grate 23 is in the main combustion. Downstream of the motorized grate 22 is located on the most downstream side. Here, the main combustion zone refers to an area where the flame is raised and burned on the garbage layer. Each of the motorized grate 21, 22, and 23 is provided with a moving fire lattice disposed between the fixed fire lattices, and after the garbage is moved back and forth by the moving fire lattice, the motorized furnace is used after the garbage (burned matter) is put into the furnace. Row 21 allows the waste to be dried, main combustion with motorized grate 22, and finally ash burning on motorized grate 23. In the embodiment, the number of the main combustion belt motorized grate 22 is three, but one or a plurality of the plurality of main combustion belts may be provided. 8 is a gray trap tank. Further, a primary combustion chamber 3 is provided above the motorized grate 21, 22, and 23, and a secondary combustion chamber 4 is provided above the motorized grate 21, 22, and 23. 19a, 19b are recirculation gas blowing nozzles provided facing the secondary combustion chamber 4. Further, the 81 system is a boiler connected to the exhaust outlet of the secondary combustion chamber 4. In the drying belt motorized grate 2 1 , the burning belt motorized grate 22 and the ash burning belt motorized grate 23 , the primary air pipes 5 1 , 5 2 ( 3 ) and 5 3 respectively are arranged in the lower bellows opening. So that the primary air is supplied from the primary air tube. 6 is a fan for primary air supply, and 5 is a primary air main pipe that connects the fan 6 and the primary air pipes 51, 52 (three), 53 respectively, and the primary air that is pumped from the fan 6 is distributed from the primary air main pipe 5. Go to the air tubes 51, 52, 53 once. The primary air pipes 51, 52, and 53 are provided with switching valves 5 4, 5 5, and 5 6 that respectively switch these. Further, the primary air main unit 5 is provided with -13- (10) 1298780, and the on-off valve 7 is opened and closed. 40 is a recirculation gas recirculation passage 16 taken out from the recirculation gas extraction port 40 in the primary combustion chamber 3 (which may also be a part of the combustion exhaust gas in the secondary combustion chamber 4 as a recirculation gas port of the recirculation gas). In the suction passage introduced to the recirculation fan 13, the recirculation gas extraction port 40 and the suction passage 31 are connected via a recirculation path 16. The inlet passage 31 is provided with an on-off valve 013 for opening and closing the recirculation inlet. 3 The raft is branched from the primary air main pipe 5, and the recirculating fan 1 swimming portion and the mixed air passage connected to the suction passage 31, 30a closes the opening and closing valve that is mixed into the air passage 30, and when the switching valve is opened, the primary air main controller 5 The primary air is supplied to the inlet of the recirculation fan 13 of the suction passage 31 through the mixed air passage S, and the primary air is mixed with the primary air and introduced to the recirculation fan 13. The 60 system is used to measure the mixed gas of the recirculated gas and the air. • Thermometer, 61 is a control device for controlling the switches of the on-off valve 7 and the on-off valve 〇1 3 valve 30a. The control device 6 1 is based on the temperature measured by the thermostat 60. The set temperature is set in such a manner as to automatically adjust the opening degree of the opening and closing valve, the opening and closing valve 〇1, and the opening and closing valve 30a, and the flow rate of the primary air flowing in the air passage 30 is added to the recirculating fan 13 The combustion exhaust gas of the circulating gas is combined with a mixing ratio of one. Then, the recirculating gas after being mixed by the recirculation fan 13 to the recirculation passage once air is connected to the recirculation passage 17 and 7) The body is extracted and passed through 3 1 . Because the loop system of the loop fan 1 3 3 open 3 0a when the 30 > re-circulation of the temperature, the switch degree measuring valve 7, adjust the air of the air 5 by 18 minutes -14 - (11) 1298780 The branches are respectively sent to the recirculating gas blowing nozzles 19a and 19b, and are discharged from the recirculating gas blowing nozzles 19a and 19b into the secondary combustion chamber 4. Further, an opening and closing valve 33 for opening and closing is provided in the recirculation passage 17 and an on-off valve 32 for opening and closing is provided in the recirculation passage 18. Further, in this embodiment, the recirculating gas at the inlet of the recirculating fan 13 is mixed with the primary air and introduced to the recirculation fan 13, but instead of the primary air, the recirculating gas is mixed and ejected to the secondary combustion chamber. • The secondary air in 4 or the air from the outside may be introduced into the recirculation fan 13 as well. The motorized grate type incinerator 2 according to the first embodiment of the present invention and its operation method pass through the recirculation gas extraction port 40 from the combustion chamber above the motorized grate (the primary combustion chamber 3 or the secondary combustion chamber 4). A part of the extracted combustion exhaust gas is used as a recirculation gas, and is sent to the recirculation gas blowing nozzles 19a and 19b via the recirculation fan 13 or the like, and is ejected from the recirculation gas blowing nozzles 19a and 19b to the secondary combustion chamber 4, respectively. In the upstream portion of the recirculation fan 13 constituting the suction passage 31 of the recirculation gas passage, the primary air (or secondary air) for combustion is directly mixed with the recirculation gas by mixing the air passage 30. Or the air from the outside is introduced into the recirculation fan 13, and the recirculation gas composed of the mixed air is recirculated to the combustion chamber by the recirculation fan 13, so that the combustion exhaust gas is cooled by the primary air. And, by mixing with the primary air, the combustion exhaust gas is diluted and introduced to the recirculation fan 13. Thereby, the heat exchanger for cooling and lowering the combustion exhaust gas (recycle gas) extracted from the combustion chamber as in the prior art is not required, and the structure of the combustion exhaust gas -15-(12) 1298780 recirculation system is simplified, and Reducing the number of constituent machines reduces the cost of equipment for waste incineration equipment. Further, since the air composed of the primary air is mixed in the recirculating gas, it is not necessary to provide a new fan or groove for air mixing, and the configuration can be simplified. Further, in the motorized grate-type incinerator, in the secondary combustion chamber 4 which is the secondary combustion region of the combustion chamber, the amount of movement of the recirculating gas or the secondary φ air is promoted to promote complete combustion. As a result, the reduction of the harmful substances is achieved, and as a result, the supply pressure of the recirculating gas or the secondary air is required to be high. Therefore, the recirculating fan 13 for recirculating the recirculated gas has a high rotation and a large centrifugal force. . Therefore, when the recirculating fan 13 has a large centrifugal stress and the temperature of the recirculating gas is high, a large thermal stress is superposed, and although it is a highly corrosive environment due to a recirculating gas composed of combustion exhaust gas in a high stress state, According to the first embodiment of the present invention, the recirculating fan 13 is cooled and cooled by the low-temperature primary air, and is diluted by the primary air to reduce the combustion exhaust gas concentration by the aforementioned cooling. The corrosion component and the salt in the exhaust gas are solidified, and a recycle gas that reduces the corrosion component is introduced. Therefore, according to the motorized grate type incinerator 2 and the method of operating the same according to the first embodiment of the present invention, the temperature of the recirculating fan 13 is lowered, and the thermal stress of the recirculating fan 13 is reduced. The recirculation gas that reduces the corrosion component is introduced into the recirculation fan 13, and corrosion of the recirculation fan 13 can be suppressed. Thereby, the low-cost recirculating fan 13' can be obtained without using a high-priced heat-resistant material to maintain the required durability and life. • 16- (13) 1298780 In particular, the temperature of the mixed gas is monitored by a thermometer 60 provided at an upstream portion of the recirculating fan 13, and the mixed gas is controlled by controlling the ratio of the above-mentioned recycled gas to air. When the temperature is 400° C. or lower, the recirculating fan 13 is used for a long period of time to have a sufficiently low thermal stress, and the melting point of a low-melting substance such as a sodium salt in a gaseous state is higher than the high temperature state of the recirculating gas. At 70 ° C, the above-mentioned low-melting point material can be completely cured, and the low-melting point substance can be prevented from adhering to the recirculating fan 13 to corrode. This effect will be specifically described. In the normal operation state, the temperature of the mixed gas of the controller 6 1 is set to 40 (TC or less, and the temperature measured by the thermometer 60 is equal to or lower than the set temperature, and the on-off valve 7, the on-off valve 013, and the on-off valve 30a are set. In this state, a part of the furnace gas of the primary combustion chamber 3 which is not helpful for combustion is mixed with the mixed air, and since it is reintroduced into the furnace as secondary air, low air which reduces the amount of newly injected secondary air is realized. Further, since the secondary air contains the furnace gas of the low oxygen concentration #, the state of the low NOx operation of the slow combustion can be realized. When the temperature of the recycle gas becomes high, it is measured by the thermometer 60. When the temperature of the mixed gas exceeds the set temperature of the control unit 61, the on-off valve 30a is opened to increase the amount of air, and the amount of recirculated gas is reduced by closing the on-off valve 013, or by using these two means, the temperature of the mixed gas is lowered. At this time, by opening the on-off valve 30a, since the primary air is reduced, the amount of primary air is kept constant by opening the on-off valve 7. By this action' The temperature of the mixed gas is often kept at 40 (TC or less), whereby the recirculating fan 13 can be operated for a long period of time, and the adhesion of the low melting point substance can be avoided, and the recirculating fan 13 can be etched by the refractory -17-(14) 1298780. [Second Embodiment] Fig. 2 is a configuration diagram of a motorized grate type incinerator according to a second embodiment of the present invention. In the second embodiment, the configuration of the first embodiment is added to the recirculation path. The cyclone 12 is provided as an example of the dust removing device. The inlet passage of the cyclone 12 and the suction passage 12a of the recirculating fan 13 are connected to the mixed air passage 30 branched from the primary air main pipe 5. In other words, in the second embodiment of the present invention, the recirculation gas composed of the combustion exhaust gas introduced into the cyclone 12 from the recirculation passage 16 is removed from the cyclone 12 by a known means. Thereafter, the primary air from the mixed air passage 30 is mixed with the recirculating gas and introduced into the recirculating fan 13. The other configuration is the same as that of the first embodiment (Fig. 1), and the same components are attached. identical Therefore, according to the second embodiment of the present invention, the dust in the gas is removed by the cyclone 1 2 provided at the upstream portion of the recirculation fan 13 of the recirculation passage 15 to purify the dust. In the recirculating gas, the primary air mixed in the air passage 30 is mixed in the same manner as in the first embodiment, and the temperature of the recirculating gas and the corrosion prevention treatment are performed. Therefore, the deterioration component of the recirculating fan 13 can be removed. The purified recirculated gas can be introduced into the recirculating fan 13, and the durability and life of the recirculating fan 13 can be improved. 0 -18- (15) 1298780 [Third Embodiment] Fig. 3 is the third aspect of the present invention. A configuration diagram of a mobile grate type incinerator according to an embodiment. In the above-described first embodiment, the cyclone 12 is provided in the recirculation passage 16, and the inlet passage 14 of the cyclone 12 is connected to the recirculation passage 16 and the inlet passage 14 is connected to the inlet passage 14 The primary air φ is in the mixed air passage 30 of the branch 5 . In other words, in the third embodiment of the present invention, the recirculation gas introduced into the cyclone 12 from the recirculation passage 16 is mixed and introduced into the cyclone 12 after being mixed with the primary air of the air passage 30. The dust in the recycle gas is removed by the cyclone 12 by a known means, and is introduced to the recirculation fan 13 . The other components are the same as those in the first embodiment (first drawing) or the second embodiment (second drawing), and the same components are denoted by the same reference numerals, and the description thereof is omitted. Therefore, according to the third embodiment of the present invention, the temperature is lowered by the mixing of the primary air mixed in the air passage 30, and the corrosion prevention treatment is performed to provide the low-temperature recirculation gas in the recirculation passage. The cyclone 12 in the upstream portion of the recirculating fan 13 of 15 removes the dust in the gas, and then introduces the recirculating gas to the recirculating fan 13, so that in the high temperature state of the recirculating gas, by the aforementioned The air is mixed, the recirculating gas is set to a low temperature, and a low-melting substance such as a sodium salt in a gaseous state is solidified, and the solid is separated from the gas by the cyclone 12 to be removed, and -19-(16) 1298780 can be completely removed. Low melting point substance. [Fourth Embodiment] Fig. 4 is a configuration diagram of a motorized grate type incinerator according to a fourth embodiment of the present invention. In the fourth embodiment, in addition to the first embodiment, the cyclone 12 is provided in the recirculation passage 16, and the inlet passage #14 of the cyclone 12 is connected to the recirculation passage 16, and is connected to the inlet passage 14. The air intake passage 3 branched from the primary air main pipe 5 has the same configuration as that of the third embodiment. In addition, in the fourth embodiment, the secondary combustion chambers 4' are provided with the recirculation gas blowing nozzles 19c and 19d on the upstream side of the recirculating gas blowing nozzles 19a and 9b, and the recirculation passages 17 are provided. And 18 are connected, and the primary air recirculating gas from the recirculating fan 13 is mixed, and is discharged from the recirculating gas blowing nozzles 19a and 19b and the two positions of the recirculating gas blowing nozzles 19c and 19d to the secondary combustion chamber 4. Internally constituted. Further, the above-mentioned recirculating gas blowing nozzle may be provided with three or more stages and the fourth embodiment of the present invention, and the first embodiment can be applied to a motorized grate type incinerator which does not have a decanting device. . The other configurations are the same as those in the above-described first embodiment (i-th) or in the second embodiment, and the same reference numerals will be given to the same members, and the description thereof will be omitted. According to the fourth embodiment of the present invention, in the form of the third embodiment -20-(17) 1298780, the recirculated gas in which the primary air is mixed is flowed from the combustion exhaust gas along the secondary combustion chamber 4. The plurality of portions are ejected to the secondary combustion chamber 4, and the mixing of the recirculating gas in the secondary combustion chamber 4 and the gas in the furnace is promoted to promote the combustion of the unburned gas in the secondary combustion chamber 4. The above description of the embodiments of the present invention is not limited to the above embodiments, and various modifications and changes can be made in accordance with the technical spirit of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a configuration diagram of a motorized grate type incinerator according to a first embodiment of the present invention. Fig. 2 is a configuration diagram of a motorized grate type incinerator according to a second embodiment of the present invention. Fig. 3 is a configuration diagram of a motorized grate type incinerator according to a third embodiment of the present invention. Fig. 4 is a view showing the configuration of a motorized grate type incinerator according to a fourth embodiment of the present invention. [Main component symbol description] 1 : Garbage hopper 2 : Motorized grate incinerator 3 : - Secondary combustion chamber 4 : Secondary combustion chamber 5 : - Secondary air main - 21 - (18) 1298780 6 : Fan 7 : Switch Valve 8: ash replenishing tank 12: cyclone 12a: suction passage 1 3 : recirculation fan 0 1 3 : switching valve φ 14 : inlet passage 15, 16, 17, 18: recirculation passages 19a, 19b, 19c, 19d : Recirculating gas blowing nozzle 2 1 : Drying belt motorized grate 22 : Main combustion belt motorized grate 23 : Combustion belt motorized grate 3 0 : Mixed air passage 3〇a : Switching valve Xin 3 1 : Suction path 32, 33 : On-off valve 40: Recirculating gas extraction ports 51, 52, 53: - Secondary air pipe 5 4, 5 5, 5 6 : On-off valve 60: Thermometer 6 1 : Control device 81: Boiler-22-