Tubes Using Thermal Sprayed Coatings. Y. Sochi, M.Tanabe, A. Takeya, Surface Treatment Division, Dai-Ichi High Frequency Co. Ltd, Kawasaki, Japan

Transcription

1 Extending the Service Life of Furnace Wall Tubes Using Thermal Sprayed Coatings Y. Matsubara, Y. Sochi, M.Tanabe, A. Takeya, Surface Treatment Division, Dai-Ichi High Frequency Co. Ltd, Kawasaki, Japan 1

2 Outline Furnace Wall Tubes at Waste Incineration Plants First Experimental Application of Furnace Wall Tubes Second Experimental Application of Furnace Wall Tubes Application of Furnace Wall Tubes 2

3 Schematic Diagram of Incineration/Power Plant Crane Furnace Filter Exhaust Stack Truck Blower Floor Generator Control Room Garbage Drainage 3

4 Schematic Diagram of Furnace 4

5 NiklB Nickel Based dslffl Self-fluxing Alloy Coatings Conventional Coatings Nickel Based Self-fluxing Alloy Induction-fused Coatings: Corrosive substances: - penetrate these coatings - strengthen metallurgical - corrode the base metal bond. - disintegrate coatings - minimize inclusion pores. - are cheaper than welded coatings. - minimize distortion, facilitating final assembly. 5

6 First Experiment Procedures 1. Specimen Tubes: 76.2mm x 990mm x 6mm 2. Thermal Spraying Process: - blasted by steel grit -sprayed with J3 tm - fused by induction heating 3. Tested Under Industrial Conditions 6

7 Figure 1: Schematic Diagram of Furnace. Furnace Wall Tubes 1123K 1223K 1423K A Screen Tube B Super Heater Gas Furnace 7

8 Figure 2: Dimensions of Test Unit 990 Treated Units 500 8

9 Table 1: Chemical Compositions of Powder and Substrate (Weight%) Powder Ni Cr Si B Mo Powder A Balance Substrate Fe C Si B Mn ASME SA192 Balance

10 Table 2: Flame Spraying and Induction Heating Conditions Flame Spraying Conditions Induction Heating Conditions Operation O M Pa, Frequency 2kHz Gas 45 l/ min C 2 H M Pa, Input Power 145kW 28 l/ min Powder Feed Rate 76 g/min Temperature K Spraying Distance 205 mm Coil Moving Speed 1.5mm/s Coating Thickness 1.5 mm 10

11 Table 3: Incinerator Conditions Waste Type Furnace Temperature Tube Pressure Tube Temperature (Outer Tube Surface) Tube Temperature (Inner Tube Surface) Household Garbage Max1323K 50MPa 5.0MPa Max 623K Max 533K 11

12 Figure 3: Appearance of Furnace Wall Tubes after Service Treated Tubes Untreated Tubes 12

13 Table 4: Thickness of Wall Tubes after 24 Months Thickness Untreated Tubes TreatedTubes Tubes (mm) a b c d e f g h Before Service After Service Loss Figure 4: Cross Section of Wall Tubes e d h f c g b a 13

14 Figure 5: Microstructure of Induction Fused Coating. Coating Substrate Cross Sections of Tubes 100μm 14

15 Figure 6a: Principle of Corrosion Mechanism by Active Oxidation (Flue Gas) O 2 NaCl KCl SO 2 O 2 (Ash Layer) (1) 2NaCl+SO 2 +O 2 =Na 2 SO 4 +Cl 2 2KCl+ SO 2 =K 2 SO 4 +Cl 2 (Corrosion Front) (2) FeCl 2 = Fe+Cl 2 (Scale Layer) (3) 2FeCl O 2 ==Fe 2 O 3 +2Cl 2 3FeCl 2 +2O 2 =Fe 3 O 4 +3Cl 2 (4) FeCl 2 +O 2 + Fe 3 O 4 =2=2Fe 2 O 3 ++Cl 2 (Metal Surface) Fe 15

16 Figure 6b: Analysis Samples of Oxide on Wall Tube Scale Outer Surface Scale Inner Surface Oxidized and Corroded Wall Tube 16

17 Figure 7a: Electron Probe Micro Analyzer Analysis of Wall Tubes (Ash Layer) SiO2 NaCl KCl KCl NaCl 17

18 Figure 7b: Electron Probe Micro Analyzer Analysis of Wall Tubes (Outer Surface of Scale Layer) K2SO4 NaCL Fe2O3 Fe2O3 Fe2O3 K2SO4 NaCL 18

19 Figure 7c: Electron Probe Micro Analyzer Analysis of Wall Tubes (Inner Surface of Scale Layer) Fe2O3 FeCl2 Fe2O3 Fe2O3 Fe2O3 FeCl2 19

20 Figure 8: Energy Dispersive X-ray Analysis of Treated Tubes After Service 20

21 Second dexperiment tprocedures Specimen Units:500mm x 6000mm x 6mm 2. Thermal Spraying Process: - blasted by steel grit -sprayed with J3 TM - fused by induction heating 3. Tested Under Industrial Conditions 21

22 Figure 9: Dimensions of Furnace Wall Tubes Specifications X<6mm, Y<4mm, Z<3mm Length<6mm, Width<3mm Coating thickness>1.2mm Coating zone X (end to end) Y (end to end) Z (side to side) 22

23 Figure 10a: X; Example of fdimensions i of ffurnace Wall lltubes Percentage 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% specification ΔX (mm) 23

24 Figure 10b: Y; Example of Dimensions of Furnace Wall Tubes Percentage 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% specification ΔY (mm) 24

25 Figure 10c: Z; Example of fdimensions i of ffurnace Wall lltubes ΔZ Percentage 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% specification ΔZ (mm) 25

26 Table 5: Flame Spraying and Induction Heating Conditions Flame Spraying Conditions Operation Gas O MPa 45 l/ min Induction Heating Conditions Frequency 2 khz C 2 H MPa Input Power 150 kw 28 l/ min Powder Feed Rate 76 g/min Temperature K Spraying Distance 205 mm Coil Moving 1.5 Speed mm/s Coating Thickness mm 26

27 Figure11: Treating Procedure of Units Figure11a: Appearance of Furnace Wall Tubes Before Treatment 27

28 Figure 11b: Appearance of Blasting Surface Roughness Ra 15μm 28

29 Figure11c: Flame Spraying 29

30 Figure11d: Induction Fusing 30

31 Figure 11e: Induction Bending of Units for Roof Section 31

32 Figure 12: Position of 11 Units in Front Furnace Wall m from floor Untreated Units m Treated Units 20m from floor Mortar Coated Unites Treated Units 32

33 Table 6: Thickness of Units after 2 and 3 Years (mm) Unit Numbers Inspection year Untreated Units Treated Units Untreated Units Treated Units Replaced Replaced

34 Application on Furnace Wall Tubes 1. Treated Panels: 450m2 at LuTsao Plant Tubes: 60.3mm x 5mm x m (SA210) Waste Type: 50% Industrial Waste 2. Treated Panels: 500m2 at Hsintien Plant Tubes: 76.2mm x 6mm x 6m (SA192) Waste Type: Domestic Garbage 34

35 Table 7: Chemical Compositions of Powder and Substrate (Weight%) Powder Ni Cr Si B Mo Powder A Balance Substrate Fe C Si B Mn ASME SA210GrC Balance

36 Figure 13: Schematic Diagram of Furnace (Lutsao Plant) 30.7m from floor 26.1m from floor Treated Units First Passage Super Heater

37 Figure 14: Schematic Diagram of Furnace (Hsintien Plant) 25.7m from floor 19.7m from floor Treated Units First Passage Super Heater

38 Figure15a: Appearance of Waste Incineration Furnace ( 5m x 7m in Width and 35m in Height ) 38

39 Figure 15b: Appearance of Roof and Front Units Roof 32 m from floor Front Units 30 m from floor Units After Service Units Before Service 39

40 Figure15c: Appearance of Front and Mortar Coated Units Front Units 26m from floor Front Units 20 m from floor Units After Service Units Before Service 40

41 Figure16: Furnace Temperature and WTE Conversion Rate 41

42 Figure 17a: Thickness of Furnace Wall Tubes After Service at 26.2m from Floor ickness(mm) Thi Front wall No1-7-units Front wall No8-14-units Rear wall No.1-7-units Rear wall No.8-14-units Right wall No.1-5-units Right wall No.6-10-units Left wall No.1-5-units Lft Left wall llno.6-10-units Inspection Year (at 26.2m) 42

43 Figure 17b: Thickness of Furnace Wall Tubes After Service at 27.2m from Floor 10 Th hickness(mm) Front wall No1-7-units Front wall No8-14-units Rear wall No.1-7-units Rear wall No.8-14-units Right wall No.1-5-units Right wall No.6-10-units Left wall No.1-5-units Inspection Year (at 27.2m) Left wall No.6-10-units 43

44 Table 8: Distribution of Treated Panels in WTE Plants in Taiwan Supply Year WTE Plant Capacity (Ton/Day) Units (Numbers) Area ( m2 ) 2004 Shulin Lutsao Houli Hsintien Taoyuan Shulin Wurih Renwu Totals

45 Conclusions - greatly extends service life. - inexpensive process - reduces distortion ti for final assembly. - displays no decrease in thickness of tubes after 40 months use 45

46 Latest Developments 1. Products & Process of ACT&P 2. Supply Record of ACT&P Boiler Tubes 3. Corrosion Test Results of ACT&P

47 ACT&P : Super Heater Super Heater of Coal Combustion Power Plant Super Heater of Waste Incineration Plant

48 ACT&P : Induction Fusing & Bending Straight Tube- Induction Fusing Bent Tube- Induction Bending

49 Partial Section of ACT&P, Coated and Bent No.1 No.2 No.3 No.4

50 Supply Record of ACT&P Boiler Tubes Supply Year Boiler Plant Boiler Tube Tube Material Tube Size Coating Thickness Tube Numbers 1993 PFBC HE,SH STBA x mm< 730 SUS Coal Combustion HE,SH STBA24 SUS347 45x mm< PFBC HE,SH STBA22, x 1.5mm< PFBC HE,SH STBA22,24 SUS ,45,50.8, mm< Sulfuric Acid Water STB x mm< Biomass HE STB x x mm< Recovery HE,SH STBA12, ,50, mm 2422 Heat STB mm Waste SH STB ,42.7 Incineration x1700, mm< CDQ HE STB x mm< 2934

51 Laboratory Corrosion Test Results of ACT&P

52 Fig.1 Schematic Illustration of Laser-detecting Thermogravimetric Apparatus Data Output mm Platinum Wire Water Inlet LASER Source & Detector Gas Inlet Water Outlet Quarz Spring Teflon Umbrella Pt Basket Mixed Salts LASER Displacement Meter Water Inlet Quarz Rod Gas Outlet Water Outlet Specimen Electric Furance (Movale)

53 Table 1: Conditions of High Temperature Corrosion Test Gas Composition 1%HCl-50%O2-N2 Flow rate 40 (cm3/min) Salts Ash from WTE Composition undetermined plant in Taiwan Prepared salt 40mol%NaCl-40mol%KCl- 20mol%Na2SO4 Specimen Powder A 10mm 10mm 1mm Inconel 625 Surface polished by sand paper #800 Temperature K (Kelvin) 923

54 Table 2: Chemical Compositions of Powder A and Inconel 625 (Weight%) Material Ni Cr Si B Mo Fe C Cu Al Nb + Ta Ti Powder A Inconel 625 balance

55 Powder A Inconel 625 Fig.2 : Microstructure of Samples before Test (etched)

56 Photo1 : Pt Basket after testing

57 Powder A Inconel 625 Fig.3 : Appearance of Corroded Sample after Testing at 923K for 72h

58 Inconel 625 Fig.4 : Mass gain curves on specimen tested with Ash from WTE plant in 1%HCl-50%O2-N2 at 650 Powder A Fig.4 : Mass gain curves on specimen tested with Ash from WTE plant in 1%HCl-50%O2-N2 at 923K Y. Sato, Akita Univ., Japan

59 Inconel 625 Powder A Fig.5 : Mass gain curves on specimen tested with prepared salts from WTE plant in 1%HCl-50%O2-N2 at 923K Y. Sato, Akita Univ., Japan

60 Thank you