ú{à®wï æ 66 ª æ 6 (2002)569_575 ÁWuø¦pü¨dvgɨ¯é·ÏHÞ¿ÌJÆ«]¿Zpv MªðKX»nZvgɨ¯éöCßMíÇÞ¿Ì · H®ÌðÍ ¬ ì ¸ ¢1 î t r a1 ü ] ² 1 Ø à p m2 1Oä¢D®ïЫGlM[ZpJZ^[ 2Oä¢D®ïЫÆ{«Ýv J. Japan Inst. Metals, Vol. 66, No. 6 (2002), pp. 569_575 Special Issue on Development and Application of High_temperature Corrosion_resistant Materials and Evaluation Technologies of Corrosion Environment in High Efficiency Waste Incineration Plant Ý 2002 The Japan Institute of Metals Analysis of High Temperature Corrosion Behavior of Superheater Tube Materials in Waste Pyrolysis Gasification and Melting Plant Shozo Ono1, Toshikazu Inaba1, Takahiro Irie1 and Hidehiro Kiuchi2 1Chiba Technology Center, Mitsui Engineering & Shipbuilding Co., Ltd., Ichihara 290_ 0067 2Environmental & Nuclear Energy System Hq., Engineering Dept., Mitsui Engineering & Shipbuilding Co., Ltd., Tokyo 134_ 0088 The demand for the highly efficient utilization of the heat generated by waste pyrolysis gasification and melting process is in creasing. However, since this process is still under development, the corrosion behavior and characteristics of superheater tubes are not fully understood. Some field corrosion tests were carried out at the model plant to determine the corrosion rate and to clarify the corrosion mechanism of superheater tubes. Thickness losses after practical operation up to 2839 h were measured along with characterization of ashes deposited on the surface of the tubes. It was found that the corrosion loss of SUS310S in creased markedly as the metal temperature rise above 500 C. Cl, S, Na, K and Ca were detected in the corrosion scale, and the deposit begins to melt at 504 C. These results indicate that the accelerated corrosion above 500 C is caused by melting of alkaline metal chlorides and sulfates in the deposit. Also, it was confirmed that alloying elements of Cr and Ni affect to reduce high tem perature corrosion caused by molten salt. (Received November 20, 2001; Accepted May 9, 2002) Keywords: waste pyrolysis gasification and melting plant, boiler, superheater tube, high temperature corrosion, alkaline metal chloride, alkaline metal sulfate, molten salt CðMªðKX»nZvZXÌfvgÉÝuµC 1. ¾ 500 C Ì·öCñû̽ßÌÞ¿]¿ðÚIƵ½ÀØ^ ]ðÀ{µ½D»ÌÊC±êÜžç©É³êĢȩÁ ¢ã^ÌIpü¨ZpƵÄCMªðKX»n ZvZX1)ÌJªiñŨèC±ÌVµ¢vZXðÌ ½{vZXɨ¯éeóâÞ¿Ì HÊC¨æÑFàÌ « H«ÉÖ·éf[^ðæ¾·é±ÆªÅ«½D pµ½pü¨{ÝÍ»ÝenÅ}¬ÉÌp³ê éD{vZXÍC©ÈMnZC_CILVÞ¶Ì} »±Å{ñÅÍCSH ÇÌ· H®ÈçÑÉ H «]¿ðåÌƵ½ãLÀر̬ÊðÐî·éD §C¢¸e»¦CL¿¨ñûCÌ_ðLµÄ¨èC «×ªá¹zÂ^ÐïÉKµÄ¢éDæÁÄC{v ZXɨ¢Äø¦Èpü¨dªÀ»Å«êÎCäª ÌGlM[«Á«ãÉßÄ]ܵ¢Æl¦çêéD ±Ìæ¤ÈÏ_©çCNEDO(VGlM[EYÆZp 2. À 2.1 ± û @ ±ppM{CÌTv úÊ 24 t Ìpü¨\ÍðL·éfvgÉÝ J@\)ÅÍMªðKX»nZvZXɨ¯édø uµ½±ppM{CÌfÊ}ð Fig. 1 ɦ·DRÄn ¦ 30÷Ìø¦³öQ^pü¨dðÚwµCevfZp ZF(HTCC)©ço½rKXÍC·óCÁMí(HTAH) Jð 1998 Nx©ç 3 NÔÉí½èsÁÄ«½2)D{C Åpü¨MªðÌM¹ÆÈé·óCðñûµ½ãCñ öCðÌ·³»ÉsÂÈßMí(SH)ÇÞ¿Ì· 650 C ÅpM{CÉüéDÎü¬Ìe|Gh^Cn HÁ«]¿Í»ÌêÂƵÄißçêCMÒçÌO[v }ODû®ðÌpµ½±ppM{CÅÍCFig. ÅÍ{vZXÌÀÊDðp¢CÀ±º±Éæéù¶Þ¿ 2 Ŧ·æ¤É 2 SH Å 400 C, 3 SH Å 500 C Ì·ß ÌÏH«]¿ÈçÑÉDÌ HÁ«]¿ðsÁ½3)D³çÉ MöCªñû³êéDMð·ðI¦½rKXÍCpM{C ±ÌÊðó¯ÄCù¶Þ¿Ì SH Ç©çÈé±ppM{ C ÆÈéD oûÅñ 450 570 æ ú { à ® w ï (2002) Fig. 1 66 ª Sectional view of boiler. Table 1 Chemical composition and operation time of SH tubes and probes adopted. Material Principal alloy composition (mass÷) Operation time (h) Alloy 625 21Cr_8.4Mo_ 3.5Nb_62Ni_ 3.8Fe 2839 SUS310S 25Cr_ 20Ni_53Fe SUS310S 25Cr_20Ni_53Fe SUS309J2 22Cr_1.5Mo_ 14Ni_ 59Fe STBA24 2.1Cr_ 0.97Mo_ 96Fe Primary SH C) (510`460 STB340 99Fe Outlet of HTAH Alloy 625 21Cr_8.4Mo_ 3.5Nb_62Ni_3.8Fe Alloy 825 22Cr_2.8Mo_ 1.8Cu_44Ni_ 27Fe Position Final SH C) (650`620 SH tubes Secondary SH C) (620`510 Inlet of final SH SUS310S 25Cr_ 20Ni_53Fe SUS309J2 22Cr_ 1.5Mo_ 14Ni_59Fe Inlet of secondary SH STBA24 2.1Cr_0.97Mo_ 96Fe Inlet of primary SH STB340 99Fe Proba Fig. 2 2.2 Example of gas, metal, and steam temperature at SH. ±Þ¿ÌØf²¸ Note: ( 1614, 1225 2839 2433 )`gas temperature C ÌÌæÉÝuµCt DÌÁ«]¿Éà xªñ 500`700 p¢½DSH ÇC¨æÑóâv[uÍ»ê¼ê 2839 hC¨ Table 1 ɱ޿ƵÄp¢½|Þ é¢Í Ni îà æÑ 2433 h ^]ãɲǵC¸÷ÊÌvªC HEÊÌX Ìåvàg¬CÝuÓC¨æÑ^]Ôð¦·D±Þ P[ªÍC¨æÑ~NgD̲¸ðsÁ½D½¾µC3 ¿ÌÏ· H«²¸ÍCÀÛÌ SH Ç̼Éóâ®Ì H SH ÇÌ SUS310S Íí¸©ÈjEÌ©Éæèð·µ½ ±Ì(v[u)ðp¢ÄsÁ½Dóâv[uÍrKX· ½ßC^]Ôª¼ÌÊæèZ¢D¸÷ÊÌvªÍC^ 6 æ 571 MªðKX»nZvgɨ¯éöCßMíÇÞ¿Ì· H®ÌðÍ ·xªètßðÚÏ@µCÊÌÅൢÓðØ CuC¨æÑAJà®Æ¢Á½áZ_»¨ð`¬·é èoµC3 mm Ì_Chy[XgÉæéfÊ̾ʤ ³fÌÜLʪärI½¢DêûCÇ¿çÌt Dà»wg ¨æÑGb`Oð{µ½ãCfW^°÷¾ðp¢ ¬ÅÍá ClC S ðÆÈÁĨèCXRD ɨ¯é NaCl, Äc¶ú³vªðsÁ½DTv 1 Ìɨ¯éc¶ú KClC¨æÑ CaSO4 Ìs[Nª¢D , 90 , 180 , 270 ³vªÊÍCrKX¬êÉε 0 Ìè_ Fig. 3 ɱêç 2 ÂÌÌæDÌ DSC ÉæéªèÊð¦ 4 ÓÉÁ¦CÅå¸÷ð¹¹½v 5 ÓƵ½D H ·D±ÌÊÉæêÎC3 ¨æÑ 2 SH Çt DÌnZ EÊÌXP[ªÍÉÍC3 ¨æÑ 2 SH ÇÌ· C ¨æÑ 501 C Å Á½DKCl_ Jn·xÍC»ê¼ê 504 (öCoû)ð£®ÅØèoµCXP[¢ÌÜÜ÷ C Å NaCl_Na2SO4 Ì 3 ³n¤»ÌnZJn·xª 518 ÅÅèµC1000 ÜÅÌG[¤ð£®Å{µ½ãC é6) ±ÆCTable 3 ɦ·æ¤É XRD Å KCl, NaClC¨æ EPMA ðp¢ÄsÁ½D~NgD̲¸ÍC¯lÉ÷ Ñ Na2SO4 ª¯è³êé±Æ©çCDSC Åo³ê½s[ ÅÅèµ½Tvð 3 mm Ì_Chy[XgÉľ NÉÍãL 3 ³n¤»ÌnZs[NªÜÜêéàÌÆ Ê¤µCGb`Oð{µ½ãCõw°÷¾ÉæéÏ CÉ l¦çêéD½¾µCªè³ê½nZJn·xÍ 518 @ðsÁ½D 2.3 t DÌÁ«²¸ SH ÇÌåvÆev[uÉt µ½DðF^]ãÉÌ Table 3 Chemical composition of ashes deposited on SH tubes and phase identified by XRD (mass÷). æµCICP @C´qzõõx@Éæé»wg¬Ì²¸C Na XRD Éæéåv\¬»¨Ì¯èC¨æÑ DSC Éæén Final SH Secondary SH 5.10 5.54 ZÁ«Ì]¿ðsÁ½D K Ca 12.4 3. Si 11.4 ʨæÑl@ 3.1 Al ^]ðÆrKX«ó 1999 N 6 ©ç 2000 N 11 ÌúÔÉCfvg ŵ½êÊpü¨Ì²Ý¿ªÍÊC¨æÑpM{C ɨ¯érKXg¬ÌªèÊã\lð Table 2 ɦ·D² ûCrKXg¬É¢ÄÍ O2 Zxª]^ÄpF4,5)Ìñ¼ ªÌ 5÷öxÆÈÁÄ¢éD±êÍC{vZXÌÁ¥Å éáóCä^]ÉNö·é·éàÌÅ éD t DÌ«ó SH ÇÌDt ÊÍCÅར 3 SH Åà 15 mm öx 6.24 XRD 6.90 12.6 9.72 5.82 Pb 0.84 1.59 Zn 1.04 0.86 Cu 0.21 0.20 Cl 2.81 3.79 S Ý¿É¢ÄÍêÊIÈss²ÝÆå«ÍÏíçÈ¢Dê 3.2 6.20 9.1 12.2 Chloride KClÞ NaClÞ KCl* NaClÞ Sulfate CaSO4Þ Na2SO4 CaSO4Þ Na2SO4 Oxide Ca2Al2SiO7 Ca(Mg, Fe)Si2O6 Ca2Al2SiO7 Ca(Mg, Fe)Si2O6 Note: Þ`strong peak Ìú³Å èCrKX·xÌáºÉº¢¸·éXüªFß çê½DܽC3 SH Ìt DÍSÌIÉdXP[É Å µÄ¢éÌÉεC2 ¨æÑ 1 SH Ìt DͲ óÅîç©¢DTable 3 É 3 ¨æÑ 2 SH Çüût D Ì»wg¬¨æÑ XRD ůè³ê½åv\¬»¨ð¦·D 3 SH Ç t D É ä × C 2 SH Ç t D Í Cl, S, Pb, Table 2 Waste Condition Gas composition in boiler Waste condition and gas composition in boiler. Lower calorific value 9.43(MJ/kg) Moisture 43.3(mass÷) Combustible 45.3(mass÷) Ash 11.5(mass÷) Cl 0.6(mass÷) O2 4.0`5.1(vol÷) CO2 11.0`14.2(vol÷) H 2O 17.2`24.6(vol÷) HClÞ 322(vol ppm) Note: Þ`measured at No. 1 bagfilter inlet Fig. 3 DSC curves of ashes deposited on SH tubes. 572 ú { à ® w ï (2002) æ 66 ª ä×ᢱƩçCãL 3 ³n¤»ÈOÌ»¨Ìe¿ª ¯ÎC»êÈOÍrKX·xÌã¸Éº¢¸·éD±êç ¦´³êéD]^ÄpFÅÌÌæDàC{ʯlÉ ÌXüÍ]^ÄpF4,5)Æ޵ĢéD 500 C OãÉnZJn_ðÂꪽ¢ª7)C±êÍêÊ IÉÍdà®ÌZ_áºøÊÆl¦çêÄ¢éD Fig. 4 ÍCSH Çåv¨æÑev[uÅÌt D S, Fig. 5 ÍCSH Çåv¨æÑev[uÅÌt D Cl ÜLÊðCrKXÆ^Ì·x·Å®µ½Êð¦·D C Ì·ÌæÅÍCrKXÆ^Ì rKX·x 600`700 Ca, Na, K, SiC¨æÑ Al ÜLÊðCrKX·xÅ®µ½ ·x·ªã¸·éÉÂêCCl ÜLÊªí¸©ÉÁ·éX Êð¦·DrKX·xÌã¸Éº¢CCa, SiC¨æÑ Al üªFßçêéD±ÌXüÍ]^ÄpF5)ƯlÅ éD ÜLÊÍÁ·éDêûCNaC¨æÑ K ÜLÊ͸· C Ìá·ÌæÅÍCrKXÆ êûCrKX·x 450`500 éDܽCS ÜLÊÉ¢ÄÍ 3 SH üû¨æÑ 2 SH ^Ì·x·Æ̾mÈ˶«ÍFßçê¸C·ÌæÉä üût DÌ 2 vbgªáOIÉÈÁÄ¢é_ð ×SÌIÉ Cl ÜLʪ¢Xü𦵽D]^ÄpF4,5) ÅÍrKX·xÌáºÉº¢ Cl ÜLÊàặéXüÅ èC{nÌ®ÆͯlÅÈ¢D 3.3 3.3.1 ±Þ¿ÌØf²¸ ¸÷Ê̪è {±É¨¢ÄÍCe±Þ¿÷úÌoÏ»ðÇÕ²¸ µÄ¢È¢½ß H¸÷̬x¥Ís¾Å éªC]^Ä pFɨ¯é SH Ç÷úÌÇÕ²¸Ê4)ÅÍC H¬xw ªú¨ü¥Æü`¥ÌÔð¦µÄ¢é±Æªñ³êÄ¢ éD»±ÅCú¨ü¥C¨æÑü`¥ÌoûÉæèe±Þ ¿ÌÅå H¬xèðZoµ½D»Ìlð^·xÉæ C ÁÄ®µ½Êð Fig. 6 ɦ·D^·x 300`450 ÌÌæÅÍ^·xÉηé H¬xèÌÁª¬³ ¢DܽCSTB340 Æ STBA24 Æ̾mÈÏH«·ªFß Fig. 4 Gas temperature dependency of S, Ca, K, Na, Al and Si concentration in deposits. Fig. 5 Temperature difference (Tg_Tm ) dependency of Cl concentration in deposits. Fig. 6 Effect of metal temperature on maximum corrosion rate constant of SH tubes and probes. æ 6 MªðKX»nZvgɨ¯éöCßMíÇÞ¿Ì· H®ÌðÍ 573 C ÈãÌÌæÅÍC ç ê È ¢ D ê û C ^ · x 450 C ð´¦ Éå«ÈÁÄ¢éD±êÍ SH Çt Dªñ 500 SUS310S Ìvbgð©éÆí©éæ¤ÉC^·xÉ éÆnZµnßé±ÆÉNö·éàÌÆl¦çêéDæÁ C tßð« ηé H¬xèÌÁªC^·x 500 ÄC±Ì·xÌæð´¦È¢±Æª· HÌ}§ÉdvÅ éÆl¦çêéDܽCAlloy 625 Ìvbgð©éÆí C ð´¦½Æ«Ì H¬x ©éæ¤ÉC^·xª 500 è Ì Á X ü ª SUS310S É ä × µ ¬ ³ ¢ D Alloy 625 Í SUS310S É ä × Cr ÜL Ê ª ᢠ± Æ ðl ¶ · é ÆC±Ì·xÌæɨ¯éÞ¿Ì Ni »ªLøÅ éÆl ¦çêéD CC¨æÑ 550 C ÅÌ[Ni{Cr]ÜLÊÁ ^·x 450 Éæé¸÷ÊÌáºXüð Fig. 7 ɦ·D]^ÄpFÅ C ¨æÑ 450 C ɨ¢ÄÍ Ìñ7) ÅÍC^·x 550 Mo YÁªLøÉìpµCÁÉ^·x 550 C ÅÍà Ì[Ni{Cr{Mo]ÜLÊÌÁÉæé H}§øʪ嫢 Æ µ Ä ¢ é D ê û Å { n Ì ê C Mo Ü L Þ ¿ Å é SUS309J2 Ì HÊÍCSUS310S Ì HÊÉäתèÓ ÉæéÎ竪å«C³çÉCÅå¸÷ÊÌݪµ å«ÈÁÄ¢é±Æª Fig. 7 Åí©éDܽC]^Ä C ɨ¯é¸÷ÊÌà[Ni{Cr{Mo]ÜL pFÅÍ 450 C ɨ¢Äà Ê˶«ª¬³¢7) ÌÉεC{nÅÍ 450 Mo ÜLÞ¿Å é STBA24 ̸÷ʪ嫢½ßÉC Fig. 7 Effect of [Cr{Ni] content on corrosion thickness loss es of materials. Fig. 8 à[Ni{Cr]ÜLÊ˶«ªå«\êÄ¢éD±Ì_© çÍCMo YÁªLøÉìp·éÆ;¢ï¢ªC{nÅÍ ±Éµ½ Mo ÜLÞ¿ªÈ¢±Æà èCMo YÁø Microstructures of final and secondary SH tubes after 1225 h or 2839 h exposure. 574 ú { à ® w ï (2002) ÊÉ¢Äl@·éÉÍ¡ãf[^ðâ·Kvª éD 3.3.2 æ 66 ª ~NgD ȨCAlloy825 Í SUS310S æèà[Ni{Cr]ÜLʪ Fig. 8 É 3 ¨æÑ 2 SH ·(öCoû)Ågp³ê ¢Éà©©íç¸CFig. 6 ɦ³êéæ¤É H¬xèª ½ Alloy 625, SUS310SC¨æÑ SUS309J2 Ì HEÊɨ SUS310S æèå«¢ÊÆÈÁÄ¢éD»Ì´öÍCà ¯ é õ w ° ÷ ¾ g D á ð ¦ · D 3 SH Å Í Alloy 625, C ÈãÌnZ Ì Cu ÉR·é Cu{ ªC^·x 500 SUS310S ÆàC 10 mm öxÌשÈÊÆ 100 mm öx `¬Â«ºÉ¨¢ÄÍÈ_»ÜÉÈé8)½ßÆè³ê ̱E HªFßçêéDêûC2 SH ÅÍ SUS310S, éD SUS309J2 Æ à ± E H Í F ß ç ê È © Á ½ D ½ ¾ µ C Fig. 9 Secondary electron and characteristic X_ray images at cross_ sectional surface zone of SUS310S in final SH tube after 1225 h exposure. Fig. 10 Secondary electron and characteristic X_ ray images at cross_ sectional surface zone of SUS310S in secondary SH tube after 2839 h exposure. æ 6 MªðKX»nZvgɨ¯éöCßMíÇÞ¿Ì· H®ÌðÍ 575 SUS309J2 ÅÍ SUS310S Éä×ÇIÈʪå«C[ · H«CÈçÑÉFàÌ« H«ð²¸µ½D¾çê½ ³ 300 mm öxÌå«ÈÚÝàFßçê½D ÊÍȺÌæ¤Évñ³êéD 3.3.3 HEÊÌ EPMA ªÍ Fig. 9 Æ Fig. 10 É»ê¼ê 3 C2 SH ·(öCo û)Ågp³ê½ SUS310S Ì HEÊɨ¯é 2 dq P ò «Ìá¢ÆµÄC_fZxC¨æÑt D Cl ÜLÊÌr KX·x˶«ª©o³ê½D CÈçÑÉ EPMA ªÍÊð¦·D 3 SH ÇÅÍ Cr ÌZkµ½A±wª HXP[É MªðKX»nZvZXÆ]^ÄpFÆÌFà Q ò SUS310S Ì H¬xèÌ^·x˶«ÍC 500 C tßð«Éå«ÈéD±êÍC{nɨ¯é SH Ç ¶ÝµÈ¢±Æ©çCCr2O3 Ûìçª`¬³êɢ« t DÉÜÜêéAJ»¨|AJ°_̤» Å éÆl¦çêéDܽC HEÊɨ¯é Cl, S, O ¨ C ÅnZµnßé±ÆÉNö·éàÌÆl¦ç ªñ 500 æÑ Na, K, CaCdà®Þ̶ÝÍC HXP[ÌÝÈ êéD 縱ENHÉàFßçêC»Ì[³ÍO\Ê©çñ 20 R ò MªðKX»nZFÅÍC]^ÄpF¯lÉÞ¿Ì mm ÜÅÌärINH̪嫢ÌæÜÅBµÄ¢éD{ NiC Cr »ª H}§ÉøÊIÅ éD½¾µCMo Y C Ít DÌnZJn·x Tv̽Ï^·x 521 ÁøÊC]^ÄpFÆÌ« H«·É¢ÄÍC{¤ 504 C ð´¦Ä¨èC±êç HXP[Éo³êéD Å;yÅ«éiKÉç¸C¡ã³çÈéÀ@f[^ÌÌ ¬ªÍnZð`¬µÄ¢½àÌÆl¦çêéDæÁÄCn æªKvÅ éD Z H̶àl¦çêC¸÷ÊÌåÉñ^µ½àÌÆ l¦çêéDêûCNH̪¬³Èé[¢Ìæɨ¢Ä {¤ÌêÍVGlM[EYÆZpJ@\(NEDO) Í Na, K, CaCâdà®ÞÍmFÅ«¸CDR¬ªÍ Cl, ©çÌÏõÆupü¨KX»nZdZpJvÌêÂÆ S, O Ìݪ¶Ý·é`ÔÅ Á½DÂÜèC±E Hæ[ µÄÀ{µ½àÌÅ éD±±É´ÓÌÓð\µÜ·D ÉD¬ªÍNüµÄ¢È¢Æl¦çêC]^ÄpFÅñ ¥³êÄ¢é Cl/S/O ÌÖ^·é¡KX H9)ªN«Ä¢ ¶ £ ½àÌÆ@³êéD 2 SH ÇÅÍCCr2O3 Ì`¬ÉNö·éÆl¦çêé Cr ÌZkµ½A±wª HXP[ÉFßçêé±Æ©çC 3 SH Éä× H«ª}ChÅ Á½Æ¾¦éD½¾ µC±ÌA±wÍXP[/àEÊɧ µÄ¨ç¸CFe n_»¨à¬ÝµÄ¢é±Æ©çCÛ쫪©Á½Æ; ¢ï¢DÀCCl, S, O ¨æÑ Na, K, CaCdà®ÞÌNü ÍXP[/à®EÊÉÜÅBµÄ¢éD{TvÌ½Ï C ÍCt DÌnZJn·x 501 C æèá ^·x 446 ¢±Æ©çnZ HÍN±è¾È¢DæÁÄCOqÌ¡ KX HÌÝÉæè¸÷ªisµ½àÌÆl¦çêéD 4. ¾ MªðKX»nZvZXÌfvgɱppM {CðÝuµCñ 3000 h Éí½è SH pÏHÞ¿ÌÏ 1) S. 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