循環(huán)流化床鍋爐摻燒石油焦及燃燒調(diào)整試驗(yàn)研究

1、技術(shù)交流循環(huán)流化床鍋爐摻燒石油焦及燃燒調(diào)整試驗(yàn)研究楊欲明(中石化金陵石化熱電廠,江蘇南京210033)摘要根據(jù)有關(guān)技術(shù)資料和金陵石化熱電廠CFB鍋爐的運(yùn)行及試驗(yàn)數(shù)據(jù),對(duì)CFB鍋爐燃用石油焦時(shí)穩(wěn)定運(yùn)行、提高燃燒效率的途徑及對(duì)污染物排放的影響進(jìn)行了研究。結(jié)果表明,CFB鍋爐摻燒石油焦后飛灰可燃物升高,鍋爐效率下降;爐膛出口過(guò)量空氣系數(shù)和氧量變化對(duì)CFB性能影響較大,運(yùn)行中應(yīng)重視二次風(fēng)量的調(diào)整;CFB鍋爐具有良好的脫硫脫氮性能,完全可以滿足摻燒高硫焦的要求。關(guān)鍵詞CFB鍋爐;石油焦;燃燒調(diào)整;燃燒特性中圖分類號(hào)TK229.6文獻(xiàn)標(biāo)識(shí)碼A文章編號(hào)10023364(2003)07003003金陵石化熱電

2、廠5、6號(hào)機(jī)組引進(jìn)美國(guó)FW公司生產(chǎn)的Pyroflow型220t/hCFB鍋爐,原設(shè)計(jì)燃料為油頁(yè)巖,后改為燃用100%煙煤或50%煙煤+50%石油焦。2000年2月動(dòng)工,2001年8月及2002年1月2臺(tái)機(jī)組床壓和流化質(zhì)量,粗床料從布置在燃燒室外兩側(cè)的冷渣器經(jīng)冷卻后排出。鍋爐主要設(shè)計(jì)參數(shù)見(jiàn)表1,設(shè)計(jì)燃煤及石灰石特性分別見(jiàn)表2和表3。表1鍋爐主要設(shè)計(jì)參數(shù)項(xiàng)目主蒸汽流量/kgs-1工況A相繼投產(chǎn)。本文簡(jiǎn)要介紹CFB鍋爐摻燒石油焦試驗(yàn)及燃燒調(diào)整情況。工況B1鍋爐概況鍋爐為高壓、單汽包、自然循環(huán)、常壓CFB鍋爐,主要由燃燒室、高溫旋風(fēng)分離器、床料回送裝置、尾部對(duì)流煙道4部分組成。燃燒室下部為錐形段(濃相

3、區(qū)),一次風(fēng)通過(guò)布風(fēng)板進(jìn)入爐內(nèi)并流化床上物料,二次風(fēng)從錐段噴口送入以達(dá)到分級(jí)燃燒的目的,較細(xì)的物料被煙氣夾帶通過(guò)燃燒室出口窗進(jìn)入2個(gè)高溫分離器,大部分物料被分離并經(jīng)密封回路返回燃燒室。在燃燒室上部與前墻垂直布置有型中溫過(guò)熱器。從分離器逃逸的飛灰和煙氣進(jìn)入尾部煙道,依次經(jīng)過(guò)三級(jí)過(guò)熱器、一級(jí)過(guò)熱器、W蒸發(fā)管、省煤器、空氣預(yù)熱器,經(jīng)靜電除塵器除塵后從煙囪排出。煙氣再循環(huán)風(fēng)機(jī)將部分煙氣回送至底渣冷卻器和燃燒室。為了控制20030110收稿日期:主蒸汽壓力/MPa主蒸汽溫度/給水溫度/鍋爐效率/%保證效率/%工況A:100%負(fù)荷,石油焦50%(熱量比)+煤50%(熱量比);工況B:100%負(fù)荷,石油焦0

4、+煤100%。表2設(shè)計(jì)燃煤特性項(xiàng)目Car/%Nar/%Sar/%Mar/%Vdaf/%數(shù)值項(xiàng)目Har/%Oar/%Aar/%Qnet,ar/kJkg-1數(shù)值un()© 1995-2005 Tsinghua Tongfang Optical Disc Co., Ltd. All rights reserved.技術(shù)交流表3設(shè)計(jì)石灰石特性SiO22.86Al2O30.31Fe2O30.31TiO2CaOMgO0.40K2O0.07Na2O0.02%灼減(燒失量)42.21燃用全煤和摻燒石油焦試驗(yàn),并在燃用全煤和摻燒不同比例石油焦的情況下,對(duì)鍋爐效率和煙氣排放作了全面的測(cè)試,同時(shí)對(duì)設(shè)備運(yùn)行

5、,特別是爐內(nèi)流化情況進(jìn)行了觀察和分析研究。以5號(hào)鍋爐為例,有關(guān)數(shù)據(jù)及運(yùn)行參數(shù)列于表6。表6調(diào)整前有關(guān)試驗(yàn)數(shù)據(jù)及運(yùn)行參數(shù)項(xiàng)目一次風(fēng)量/m3s-1二次風(fēng)量/ms床溫/3-12石油焦特性金陵石化熱電廠5、6號(hào)機(jī)組鍋爐設(shè)計(jì)用石油焦為本公司延遲焦化的副產(chǎn)品,其特性見(jiàn)表4,石油焦與部分燃料燃燒特性比較見(jiàn)表5。表4石油焦特性項(xiàng)目Car/%Nar/%Sar/%War/%Qgr/kJkg-1100%煙煤23%石油焦41%石油焦57%石油焦+77%煙煤+59%煙煤+43%煙煤一次風(fēng)室壓力/kPa數(shù)值項(xiàng)目Har/%Oar/%Aar/%Qnet/kJkgVar/%-1數(shù)值床壓/kPa爐膛平均溫度/排煙溫度/爐膛出口氧

6、量/%飛灰可燃物/%底灰可燃物/%飛灰/底灰比排煙熱損失/%機(jī)械未完全燃燒熱損失/%鍋爐熱效率/%表5石油焦和部分燃料的燃燒特征溫度比較煤種晉城無(wú)煙煤南桐貧煤石油焦大同煙煤TITPTBTcrit547508554462492437443396594592512522676658649589試驗(yàn)中,為保持煙氣中SO2濃度(標(biāo)準(zhǔn)狀態(tài))低于600mg/m3,鈣硫摩爾比始終保持在22.2左右。表5所列數(shù)據(jù)是在熱天平升溫速率保持為20/min的試驗(yàn)條件下取得的。TI為著火溫度(失重速率保持為1%時(shí)的溫度);TP為失重最大時(shí)的溫度;TB為燃盡溫度(失重速率保持為95%時(shí)的溫度);Tcrit為以溫度表征的燃

7、料反應(yīng)特性溫度(失重速率保持為6.5%時(shí)的溫度)。燃盡溫度TB越高說(shuō)明燃料越難以燃盡,而反應(yīng)溫度Tcrit越高,則燃料的反應(yīng)活性越低。由表5可見(jiàn),石油焦的著火溫度與燃盡溫度均高于煙煤,但小于無(wú)煙煤,與貧煤相當(dāng),其燃盡特性比煙煤差,但好于無(wú)煙煤,基本相當(dāng)于貧煤。因此,石油焦的燃燒特性與貧煤相當(dāng)。另外,對(duì)用于實(shí)驗(yàn)室熱態(tài)試驗(yàn)的煤和石油焦的哈氏可磨性指數(shù)HGI分別進(jìn)行了測(cè)定,其中煙煤哈氏可磨性指數(shù)HGI為88、石油焦為92,兩者可磨性相近,均接近易磨煤種。但制粉過(guò)程中發(fā)現(xiàn),石油焦雖然疏松易碎,但具有一定的粘性,對(duì)此應(yīng)予以重視。由表6可見(jiàn),隨摻焦比的增大,飛灰可燃物相應(yīng)上升,機(jī)械未完全燃燒損失增大;但排

8、煙溫度有所下降,因而排煙損失隨之降低。實(shí)際運(yùn)行證明:石油焦與煤混合對(duì)燃料制備(破碎)無(wú)明顯影響,燃用混合燃料時(shí),床內(nèi)流化情況和冷渣器工作都正常。從物理性質(zhì)來(lái)講石油焦疏松易碎,在同樣的流化風(fēng)速下有利于正常流化;但其粘性較強(qiáng),結(jié)焦的可能性較大。把石油焦與煤均勻混合,加上脫硫用石灰石的作用,就基本上解決了這個(gè)矛盾。3.2爐膛出口過(guò)量空氣系數(shù)及爐內(nèi)氧量分布對(duì)燃燒特性的影響爐膛出口過(guò)量空氣系數(shù)的變化對(duì)燃燒十分重要。由于流化床屬于低溫燃燒,物料與空氣在爐內(nèi)的橫向流動(dòng)較煤粉爐弱,所以爐膛出口總氧量的多少并不能完全反映爐內(nèi)燃燒狀況,這一點(diǎn)與煤粉爐差別較大。通過(guò)對(duì)爐內(nèi)氧量的測(cè)量表明,爐內(nèi)氧量分布嚴(yán)重不均。大量的

9、試驗(yàn)數(shù)據(jù)表明,氧量的有效使用和斷面分布與爐膛出口氧量的大小沒(méi)有關(guān)系,需要進(jìn)行更精確的描述。四川電力試驗(yàn)研究院針對(duì)這個(gè)問(wèn)題提出了()3燃燒調(diào)整前后的試驗(yàn)研究3.1燃燒調(diào)整前金陵石化熱電廠5、6號(hào)機(jī)組鍋爐在投產(chǎn)后進(jìn)行了vn© 1995-2005 Tsinghua Tongfang Optical Disc Co., Ltd. All rights reserved.技術(shù)交流氧量使用效率的概念,對(duì)分析問(wèn)題十分方便。所謂氧量使用效率,是在爐內(nèi)空氣噴口之上,沿爐膛高度方向同一軸線上2個(gè)測(cè)量點(diǎn)處測(cè)量氧氣含量,其氧量消耗量與未消耗氧量之比即氧量使用效率,表達(dá)式如式(1),氧量測(cè)量示意見(jiàn)圖1。氧量使

10、用效率=X處氧量-X處氧量×100%X1處氧量(1)墻給煤,后墻煤粒濃度較高,在同樣的供氧條件下,氧氣使用效率較高,出現(xiàn)消耗過(guò)度;(3)二次風(fēng)的穿透能力較弱。3.3燃燒調(diào)整后通過(guò)對(duì)前后墻二次風(fēng)量的調(diào)整,加強(qiáng)后墻供風(fēng)量,減小前墻供風(fēng)量,使?fàn)t膛中心氧量分布均勻性有所提高,調(diào)整后斷面氧量分布見(jiàn)圖3。圖3調(diào)整后爐內(nèi)氧量分布示意圖1氧量測(cè)量示意在爐膛出口過(guò)量空氣系數(shù)不變的情況下,爐膛中部的氧量提高了3%左右,飛灰可燃物降低2%以上(由10%以上降為8%)。在此基礎(chǔ)上,將爐膛出口過(guò)量空氣系數(shù)從4%降至3.01%以下,飛灰可燃物沒(méi)有因此而上升,排煙溫度也基本不變,排煙損失進(jìn)一步下降。表7為調(diào)整試驗(yàn)

11、后的結(jié)果。表7調(diào)整后有關(guān)數(shù)據(jù)及運(yùn)行參數(shù)項(xiàng)目一次風(fēng)量/m3s-1二次風(fēng)量/m3s-1一次風(fēng)室壓力/kPa床溫/床壓/kPa爐膛平均溫度/排煙溫度/爐膛出口氧量/%飛灰可燃物/%底灰可燃物/%飛灰/底灰比排煙熱損失/%機(jī)械未完全燃燒熱損失/%鍋爐熱效率/%100%煤粒在錐段的燃燒主要處于還原氣氛中。隨著二次風(fēng)的逐漸加入,煤粒進(jìn)一步燃燒,在低溫燃燒條件下,氧量與煤粒的混合十分重要,爐膛各斷面的氧量使用效率越高,煤粒越能高效燃燒,鍋爐效率亦有可能提高。為了測(cè)量爐內(nèi)氧量分布情況,在鍋爐前、后墻的左、中、右不同高度安裝了爐內(nèi)煙氣分析測(cè)點(diǎn)。通常工況下,在二級(jí)過(guò)熱器下部進(jìn)行爐內(nèi)氧量分布測(cè)試,從前墻插入3000

12、mm左右,在后墻對(duì)應(yīng)位置進(jìn)行同樣測(cè)量。試驗(yàn)發(fā)現(xiàn)沿爐膛斷面的氧量分布規(guī)律如下:前墻氧量5%8%,后墻氧量3%6%,中心區(qū)域氧量1%左右,比較低(距前墻大約2m左右,距后墻大約3m左右)。由測(cè)試試驗(yàn)數(shù)據(jù)整理出爐內(nèi)的氧量分布曲線見(jiàn)圖2。煙煤23%石油焦41%石油焦57%石油焦+77%煙煤+59%煙煤+43%煙煤圖2爐內(nèi)氧量分布示意3.4煙氣排放測(cè)量結(jié)果在習(xí)慣配風(fēng)的狀況下,前、后墻氧量分布表明:(1)前墻氧量消耗較小,主要原因是煤粒濃度較低,在同樣的供氧條件下,氧氣使用效率較低,出現(xiàn)過(guò)剩;(2)后墻氧量消耗較大,主要原因是系統(tǒng)采用后wn()煙氣排放測(cè)量數(shù)據(jù)見(jiàn)表8。根據(jù)我國(guó)環(huán)保的有關(guān)規(guī)定:煙氣排放量須將

13、實(shí)測(cè)值換算成過(guò)量空氣系數(shù)為1.4(即6%O2)時(shí)的濃度值作為最后結(jié)果。表8中的“修正值”即為按此規(guī)定修正后的值。(下轉(zhuǎn)第51頁(yè))© 1995-2005 Tsinghua Tongfang Optical Disc Co., Ltd. All rights reserved.技術(shù)交流表3汽缸調(diào)整前、后的前軸封及各級(jí)動(dòng)葉頂部汽封間隙測(cè)量值測(cè)量位置調(diào)整前調(diào)整前左右左右各段軸汽封間隙mm動(dòng)葉頂部汽封間隙3結(jié)論4號(hào)機(jī)于2002年11月26日開(kāi)機(jī)至今,汽缸負(fù)脹改造。計(jì)劃下次檢修時(shí),可將2漏與5段抽汽管的匯合點(diǎn)從抽汽口附近下移,并在5段抽汽管道上,與2漏匯合點(diǎn)之間加裝閥門(mén)和溫度測(cè)點(diǎn),根據(jù)溫度顯示,

14、一旦前軸封漏汽增大使汽缸負(fù)脹差增大,影響到汽輪機(jī)安全運(yùn)行時(shí),關(guān)閉該閥門(mén)不讓高溫蒸汽漏入汽缸。參考文獻(xiàn)1康德.汽輪機(jī)設(shè)備安裝工藝學(xué)M.北京:水利電力出版差明顯減小,電負(fù)荷48MW(滿負(fù)荷),供汽流量45t/h,負(fù)脹差最大2.7mm,小于極限值2.8mm,證明所采取的措施是有實(shí)效的。由于種種原因,本次大修未對(duì)軸封漏汽管道進(jìn)行社,1989.(上接第29頁(yè))參考文獻(xiàn)PitchandcokecombustioninacirculatingfluidizedbedJ.Fu2el,1995,74(10):14151423.2JacquesBarthelemy,MikeTanca,GinaRuggeri,et

15、al.Eco2Designconsiderationsofthe2×1500MWFormosaheavyindus2trycorporationCFBboilerandNIDsystemA.In:16thInterna2tionalconferenceonfluidizedbedcombustionC.May1316,2001,Reno,NevadaUSA.4MichaelAlliston,AskoRantee,MattiRautanen.Experiencewithfulesfrombiomasstopetroleumcokeandhowtheirproperi2tiesaffec

16、tfluidizedbedboilerplantdesignA.In:16thInterna2tionalconferenceonfluidizedbedcombustionC.May1316,2001,Reno,NevadaUSA.5陳勇.使用石灰石添加劑對(duì)循環(huán)流化床鍋爐燃燒計(jì)算的(上接第32頁(yè))表8煙氣排放測(cè)量結(jié)果項(xiàng)目實(shí)測(cè)SO2排放值/mgm-3-3工況A工況B修正后SO2排放值(6%O2)/mgm實(shí)測(cè)NOx排放值/mgm-3修正后NOx排放值(6%O2)mgm-3測(cè)量結(jié)果均為標(biāo)準(zhǔn)狀態(tài)下數(shù)值由表8可見(jiàn),CFB鍋爐的SO2排放濃度(標(biāo)準(zhǔn)狀態(tài))均低于600mg/m3。表明這臺(tái)爐的脫硫性能達(dá)到合

17、同保證值,且能有效地降低NOx排放。4結(jié)論(1)石油焦的燃燒特性與貧煤相當(dāng),其可磨性與煙煤相近。石油焦與煤混合對(duì)燃料制備無(wú)明顯影響。(2)CFB鍋爐摻燒石油焦總的趨勢(shì)是飛灰可燃物升高,鍋爐效率下降。(3)爐膛出口過(guò)量空氣系數(shù)和氧量的變化對(duì)CFB鍋爐性能影響較大,運(yùn)行中應(yīng)重視二次風(fēng)量的調(diào)整。(4)CFB鍋爐具有良好的脫硫脫氮性能,完全可以滿足摻燒高硫焦的要求。參考文獻(xiàn)1金陵石化熱電廠CFB鍋爐性能考核試驗(yàn)報(bào)告R.2002.2岑可法,等.循環(huán)流化床鍋爐理論設(shè)計(jì)與運(yùn)行M.中國(guó)影響J.余熱鍋爐,1997.電力出版社,1998.()© 1995-2005 Tsinghua Tongfang O

18、ptical Disc Co., Ltd. All rights reserved.vpTHERMALPOWERGENERATIONVol.33No.7Jul.2003Contents&AbstractsDEVELOPMENTANDPROSPECTSOFENERGYANDPOWERENGINEERINGChenXuejun(2)Theimportanceofenergyandpowerengineeringuponthedevelopmentofnationaleconomyhasbeenexpounded,thedevelopmentdirectionsofsaidengineeri

19、nginthefuturebeingdiscussedareasfollows:enhancingtheutiliztionefficiencyofcoal,petroleumandnaturalgas;adoptingcoal-cleaningandpurifyingtechnology;aswellasdevelopingandutilizingcleanandregenerableenergysource.Weshouldmakeeffortstoresearchnewenergytechnology,creatingexquisite,cleanandharmoniousecologi

20、calenvironmentforthehumanity,establishingimportantmaterralbaseforsustainableeconomicdevelopmentofourcountry.Onthebasisofanalysingthreetypesofbypassinstallationfordomesticsupercriticalunits,namelythree-purposevalveby-passsystem,integralby-passsystem,andthree-stageby-passsystem,atentativeideaforinstal

21、lationandtype-selectionconcerningsteamturbinesby-passsystemofhome-madesupercriticalunitatQinbenPowerPlanthasbeenputforward.Itisconsideredthattheinstallationofby-passsystemfor600MWsupercriticalunitatQinbeiPowerPlantisextremelynecessary,andthecapacityofhighpres2sureby-passsystemshouldbeabout50%ofBMCR.

22、INSTALLATIONANDTYPE-SELECTIONOFTHEBY-PASSSYSTEMFOR600MWSUPERCRITICALUNITATQINBEIPOWERPLANTHuoDongfang(10)Thefeaturesofheatandelectricityload-distributionforheat-supplyingunitshavebeenanalysed,amathematicmodelofload-distributionoptimizationforheat-supplyingunitsbeingestablished.Byusingthesimulatedann

23、ealingalgorithm,anoptimaldistributionofheatandelectricityloadsbetweentwounitsinapowerplanthasbeencarriedout.Resultsshow,thisoptimizationmethodissimpleandeasytouse,canbeusedtoenhancetheeconomicaspectofthermalpowerunits.ASTUDYONAPPLICATIONOFSIMULATEDANNEALINGALGORITHMINLOAD-DISTRIBUTIONAMONGHEAT-SUPPL

24、Y2INGUNITSWenZhigangetal(18)Performancemonitorandenergy-lossanalysisofthermalpowergeneratingunitsareimportanttoeconomicoperation,energy-savingandloss-reductioninthermalpowerplants.Themethodofenergy-lossanalysishasbeenpresentedindetail.Theconcretestructureandfunctionsofaperformancemonitoringandoperat

25、ionmanagingsystemforathermalpowerplanthavebeendescribed,providingaguidinganddecision-makingbasisforeconomicoperation.STUDYONPERFORMANCEMONITORINGANDOPERATIONMANAGINGSYSTEMOFTHERMALPOWERGENERATINGU2NITSLiWenetal(21)DETERMINATIONOFTHEOPTIMUMPRESSUREFORSLIDING-PRESSUREOPERATIONOFTURBINEUNITBYUSINGBPNEU

26、RALNETWORKHuBingetal(24)Astudyonthepeformanceofsliding-pressureoperationforturbineunithasbeencarriedoutbyusingbackpropagation(BP)neuralnetwork,andtheperformanceparametersofsaidoperationbeingoptimized.TheresultsshowthattheapplicationofBPneuralnetworkcanmoreaccuratelyworkoutthecomputationforspecifiche

27、atconsumptionofthesaidturbineunitinsliding-pressureoperationunderdifferentloadswithdifferentinitialpressure,thustheoptimalinitialpressurecanbedetermined.InviewofthepropertiesofPetroleumcoke,studyandanalysisofCFBboilersforburningpetroleumcokehavebeencarriedoutfromsomeaspects,suchascombustion,ignition

28、andstabilizationofcombustion,andburn-upofpetroleumcoke,aswellasslagginginthefurnace,supplementofbed-materials,andcorrosionetc.,andcorrespondingtechnicalmeasuresinthedesignbeingrecommended.TheproblemofSO2emissioncausedbyburningpetroleumcokewithhighsulfercontentcanbecontrolledbyusingCFBboilers,andthec

29、orrosionofhealtingsurfacecanbealleviatedthroughreasonabledesignofthesaidheatingsurface.STUDYONCFBBOILERSOFBURNINGPETROLEUMCOKEChenYongetal(27)Basedonrelatedtechnicaldocuments,aswellasoperationandtestdataobtainedfromCFBboilersinJinglingPetrochemicalThermalPowerPlant,studyonstableoperationduringthetim

30、eofburningadmixtureofpetroleumcoke,onwaystoenhancecombustionefficiency,andontheinfluenceofpollutantemissionhasbeencarriedout.Theresultsshow,afterburningadmixtureofpetroleumcoke,thecombustiblesinflyashisincreased,theboilerefficiencyisdecreased,theinfluenceofvariationconcerningcoefficientofexcessairan

31、dofoxygenrateattheboileroutletuponperformanceofCFBboileriscomparativelylarge,hence,greatattentionshouldbepaidtoadjustmentofsecondaryairflowinoperation;How2ever,CFBboilershavegoodabilityofdesulfurationanddenitrification,satisfyingcompletelytherequirementsofburingadmixtureofhighsulphurcoke.TESTANDRESE

32、ARCHONBURNINGADMIXTUREOFPETROLEUMCOKEINCFBBOILERANDCOMBUSTIONCONTROLTHEREOFYangYuming(30)Theaffectingregularityoffirst-stagepulverizedcoal(PC)concentrationinmulti-stageoil-lessignitiontechnologyhasbeenstudied.Thefirst-stagePCConcentrationaffectsdi2rectlythefirst-stageoutletfluegastemperatureandcombu

33、stibegascontentinthefluegas,butthefirst-stageoutletfluegastemperatureisadecidingfactorfortheignitionofsec2ond-stagePC.Meanwhile,thecombustiblegascontentinthefirst-stageoutletfluegasishelpfultotheignitionofsecond-stagePC.Hence,theinfluenceoffirst-stagePCcon2centrationuponfirst-stagecombustionhasavery

34、importanteffectinmulti-stageignition.AFFECTINGREGULARITYOFFIRST-STAGEPULVERIZEDCOALCONCENTRATIONINMULTI-STAGEOIL-LESSIGNI2TIONTECHNOLOGYZhouJunhuetal(33)Onthebasisofexperiments,theresistancecharactersoftwodifferenttypeburnershavebeenstudied.Theinfluenceofelbow,inner-positionedwedge,andswirlingflowpl

35、ateupontheresistancecharactersofburnershasbeenanalysed,providingimportantsignificanceforguidingthedesignofburnersandcoal-pulverizingsystem,aswellasstablecombustioninboilers.STUDYONTHERESISTANCECHARACTERSOFTWONOVELTYPEBURNERSDuLilongetal(36)Inviewofsolid-wastefeedingrequirementsforCFBinceneratorofmunicipalsolidwaste(MSW),aswellasthespecialconstitutionofMSW,adesignideaofmulti-purposedou2ble-screwMSW-feedingmechanismhasbee