Ash Deposition and Shedding in Straw and W ood Suspension-Fired - PowerPoint PPT Presentation

Ash Deposition and Shedding in Straw and W ood Suspension-Fired Boilers : Full-scale Measurem ents Student: Muham m ad S. Bashir Supervisors: Professor Kim Dam -Johansen Asso. Prof. Peter A. Jensen Asso. Prof. Flem m ing Frandsen Asso. Prof. Stig W edel CHEC Research Centre, Technical University of Denm ark

Presentation Outline • Background • Experiments • Experimental Objectives • Materials and Methods • Results and Discussion • Experimental Set Up • Quantification of Deposit Buildup • Deposit Shedding using Artificial Sootblowing • Elemental Release of Major Ash Components • Conclusions/ Experimental Findings 2 2 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Ash Deposition during Biom ass Com bustion Biomass (straw) K, Cl, S Increased risk of fouling/slagging on heat exchange surfaces. AMV2 Superheater Region L. Tobiasen et al; Fuel Processing Technology, 88 (2007) 1108-1117. 3 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Boiler Configuration : AMV1 Param eter AMV1 Capacity 350, 320 (wood, straw) MWth Wood, Straw 20 pellets kg/ s (full load) Steam Data 540 Superheater ( o C) 4 4 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Boiler Configuration : AMV2 Param eter AMV2 Capacity 250 MWth (wood, straw) Wood, Straw pellets 60 t/ h (full load) Steam Data 480 Superheater ( o C) 5 5 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Experim ents • Measurement of extent of boiler fouling/ slagging by means of an ash deposition/ shedding probe. • Influence of fuel type, boiler load, probe metal temperature and probe exposure time on deposition rate, heat uptake and deposit characteristics. • Investigation of PIP needed to remove the deposits of different exposure time and probe surface temperature. • Investigation of residual ash and deposits chemistry. 6 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Deposition/ Shedding Probe 600 7 7 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Experim ental Setup Description ( AMV 1 ) 8 8 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Experim ental Resum e : AMV2 Test No. 1 3 2 4 5 Straw (% ) 35 65 80 100 0 4.21 4.99 5.38 5.85 3.3 Ash (% ) Probe Temp. ( o C) 500 500 500 500 500 Exposure Time 90 72 124 76 24 (h) Boiler Load (% ) 46 63 50 53 52 9 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Experim ental Resum e : AMV1 Test No. 1 2 3 5 4 7 6 8 Straw (% ) 80 65 35 50 50 0-10 0-10 0-10 App. Ash (% ) 5.2 4.0 2.4 3.4 3.4 1.0 1.0 1.0 500 550 550 550 Probe Temp. ( o C) 500 600 500 500 (600) 335 434 212 Exp. Time (h) 56 45 185 168 73 62 60 60 Boiler Load 66 57 62 64 86 Oil Share (% ) 12.9 13.5 2.4 7.1 4.8 2.7 5.3 6.9 10 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment AMV1 : Prim ary Data ( 1 2 0 s) : 5 0 % Straw ( flue gas: 8 4 3 o C) 0 -185 h (500) Actual flue gas temp. (suction pyrometer, Qualitative trend is same as of thermocouple) Gas Temp.( o C) 1000 Thermocouple 800 600 0 20 40 60 80 100 120 140 160 180 Time [h] 10000 Weight Uptake (g/m 2 ) 5000 0 0 20 40 60 80 100 120 140 160 180 Time [h] 0 20 40 60 80 100 120 140 160 180 100 Sootblower 120 Heat Uptake (kW/m 2 ) 50 100 80 0 0 20 40 60 80 100 120 140 160 180 Time [h] 11 11 11 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment AMV1 : Prim ary Data ( 1 2 0 s) : 5 0 % Straw ( avg. flue gas: 8 8 0 o C) 0 -30 h (500) 30 -94 h (600) 94-145 h (500) 145 -168 h ( 600) Gas Temp.( o C) Actual flue gas temp. (suction pyrometer, Qualitative trend is same as of thermocouple) 1000 Thermocouple 800 600 0 20 40 60 80 100 120 140 160 Time [h] 4 2x 10 Weight Uptake (g/m 2 ) 1 0 0 20 40 60 80 100 120 140 160 Time [h] 0 20 40 60 80 100 120 140 160 80 Sootblower (kW/m 2 ) Heat Uptake 120 40 100 80 0 0 20 40 60 80 100 120 140 160 Time [h] 12 12 12 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Flue Gas Tem perature and Heat Uptake 100 100 100 Heat Uptake Heat Uptake Heat Uptake 90 linear 90 90 linear linear y = 0.1247*x - 55.35 y = 0.06928*x - 29.89 y = 0.1427*x - 70.12 80 80 80 70 70 70 60 60 60 (kW/m 2 ) (kW/m 2 ) (kW/m 2 ) 50 50 50 40 40 40 30 30 30 20 20 20 10 10 10 0 0 0 500 550 600 650 700 750 800 850 900 950 500 500 550 550 600 600 650 650 700 700 750 750 800 800 850 850 900 900 950 950 Gas Temp.( o C) Gas Temp.( o C) Gas Temp.( o C) 13 13 13 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Brief Results of Tests Test No. 1 2 3 5 4 7 6 8 Straw (% ) 80 70 50 50 30 10 5 0 Ash (% ) 5.0 4.3 3.4 3.4 3.0 1.0 0.8 0.7 500 Probe Temp. ( o C) 500 600 500 500 550 550 550 (600) 56 45 185 168 73 335 434 212 Exp. Time (h) Boiler Load 66 57 62 64 86 62 60 60 12.9 13.5 2.4 7.1 4.8 2.7 5.3 6.9 Oil Share (% ) Flue Gas Temp. 852 821 843 880 918 774 724 788 Mean ( o C) Weight Uptake 3.78 4.95 3.07 16.26 7.34 1.95 1.82 -- Final (kg/ m 2 ) Heat Uptake 14 14 14 34 21.1 35.0 23.3 41.1 -- 24.0 -- DTU Chem ical Engineering Mean(kW/ m 2 ) Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Overall Com parison of W eight Uptake of Different Full Scale Measurem ents ( 4 5 h) Probe Flue Final Boiler Fuel Analysis gas Weight Ref. Temp. Temp. Signal Tests Ash K Cl o C o C kg/ m 2 Avedøre Test 1 5.5 0.69 0.32 500 1020 9.50 [ 11] Avedøre Test 2 4.7 0.92 0.35 500 784 1.50 [ 6] Amager Unit 2 5.9 0.83 0.40 500 830 1.70 (Test 4) Amager Unit 1 5.0 -- -- 500 852 2.20 (Test 1) Amager Unit 1 3.4 -- 0.25 500 843 0.45 (Test 3) Amager Unit 1 3.0 -- -- 500 918 4.90 (Test 4) Amager Unit 1 4.3 -- -- 600 821 4.95 (Test 2) Amager Unit 1 15 3.4 -- -- 600 880 9.60 DTU Chem ical Engineering (Test 5) Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Overall Com parison of W eight Uptake of Different Full Scale Measurem ents ( 7 2 -7 7 h) Probe Flue Final Boiler Fuel Analysis gas Weight Ref. Temp. Temp. Signal Tests Ash K Cl o C o C kg/ m 2 Avedøre Test 1 5.5 0.69 0.32 500 1022 15.0 [ 11] Avedøre Test 2 4.7 0.92 0.35 500 784 2.40 [ 6] Amager Unit 2 5.9 0.83 0.40 500 830 1.67 (Test 4) Amager Unit 1 3.4 -- 0.25 500 843 1.01 (Test 3) Amager Unit 1 3.0 -- -- 500 918 7.34 (Test 4) Amager Unit 1 3.4 -- -- 600 880 10.0 (Test 5) 16 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Ash Deposit Rem oval using Artificial Sootblow ing Probe ( Exam ple: Test 3 ( 5 0 0 ) ) Gas Temp.( o C) 60 70 80 90 100 110 120 1000 1000 Thermocouple Suction Pyrometer ( o C) 800 800 600 600 60 70 80 90 100 110 120 Time [h] 10000 Weight Uptake Shedding through plant sootblowing (g/m 2 ) Shedding through artificial sootblowing 5000 0 60 70 80 90 100 110 120 Time [h] 60 70 80 90 100 110 120 80 Sootblower Heat Uptake 120 (kW/m 2 ) 40 100 80 0 60 70 80 90 100 110 120 17 17 17 DTU Chem ical Engineering Time [h] Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Artificial Deposit Rem oval: I m age Analysis Probe Exposure Time : 91.2 h Straw Share : 50 % Flue gas temperature : 825 C Boiler Load : 65 % Target Probe Temperature : 500 o C Image Before Image After Deposit Deposit Removal Removal Weight Signal : 8747.18 g/m 2 Weight Signal : 1584.83 g/m 2 18 18 DTU Chem ical Engineering Technical University of Denmark

Background Experiments Results and Discussion Conclusions Acknowledgment Air Pressure and PI P 300 250 200 PIP (kPa) 150 100 50 0 0 50 100 150 200 250 300 350 400 450 500 Air Pressure (kPa) 20 cm 15 cm 13 cm 11 cm 9 cm 7 cm 5 cm 19 DTU Chem ical Engineering Technical University of Denmark