Uppgradering av rökgasreningssystem

Transcription

1 Uppgradering av rökgasreningssystem Bo Herrlander Södertälje, Agenda 1st topic 2nd topic 3rd topic 4th topic 5th topic 6th topic Introduction Fuel flexibility Regulations Particulate / Heavy metals Acid gases Summary & Conclusion Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 2 Information contained in this document is 1

2 Introduction One of the more common reasons for upgrading a gas cleaning plant is an increase in production of heat and electric power Also there are more and more fuel fractions available on the market, that may offer better economy Such changes may lead to change in gas flow fly ash particle size and composition gaseous compounds and concentration And most likely the gas cleaning plant has to be upgraded to meet new emission regulations This presentation will go through some available options to increase the performance of particulate and acid gas abatement Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 3 Information contained in this document is Agenda 1st topic 2nd topic 3rd topic 4th topic 5th topic 6th topic Introduction Fuel flexibility Regulations Particulate / Heavy metals Acid gases Summary & Conclusion Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 4 Information contained in this document is 2

3 Some Biomass Fired Plants Gas Cleaning Options Simplified Biomass classes Emissions Cleaning system Virgin wood Straw Particulate ESP or FF Biomass Contaminated wood Municipal Waste Particulate Acid gas Heavy metal Dioxin DAS or NID Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 5 Information contained in this document is Biofuels Some examples Biofuels heat value Biofuels water content Heat value (MJ/kg) Coal Water (%) Bark Saw waste Forest residues Waste wood Wood powder (dry) Rape Press Reminder 0 Bark Saw waste Forest residues Waste wood Rape Press Reminder Wood powder (dry) Most Biofuels Energy Density and Water Content makes it uneconomical to transport further distances In Sweden the average transport distance is 70 to 100 km The local composition of available Biofuel varies Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 6 Information contained in this document is 3

4 Typical Firing Diagram 50% influence on gas flow for the same energy conversion Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 7 Information contained in this document is Combustion process influence on particle size Fly Ash Mean Particle Size 10 Mean Particle Size (µm) 1 Pulverized Combustion Fluid Bed Grate Bark Wood Rape Press Reminder 0,1 Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 8 Information contained in this document is 4

5 Raw Gas composition range Raw gas concentration (mg/nm3) Dust EfW Dust Biomass HCl EfW HCl Biomass SO2 EfW SO2 Biomass Raw gas concentration (mg/nm3) ,5 1,0 0,1 0,4 0,5-1,0 Hg 3-8 Hg Cd + Tl 0,1-0,4 Cd + Tl 3 7 Other HM EfW Biomass EfW Biomass EfW Other HM Biomass Huge variation of particulate concentration HCl and SO 2 variation is similar between EfW and Biomass Up to five time higher heavy metals concentration in EfW compared with Biomass Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 9 Information contained in this document is Agenda 1st topic 2nd topic 3rd topic 4th topic 5th topic 6th topic Introduction Fuel flexibility Regulations Particulate / Heavy metals Acid gases Summary & Conclusion Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 10 Information contained in this document is 5

6 Consequence of the IPPC and the new Industry Directive Customers asks for lower ELVs in order to get public acceptance and permit New plants with lower ELVs becomes BAT Driving down the emissions New plants are permitted with lower ELVs New plants are built and commissioned with lower ELVs Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 11 Information contained in this document is Agenda 1st topic 2nd topic 3rd topic 4th topic 5th topic 6th topic Introduction Fuel flexibility Regulations Particulate / Heavy metals Acid gases Summary & Conclusion Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 12 Information contained in this document is 6

7 ESP experience for ESP after Grate Boilers fired with Woody Biofuels Emission (mg/nm^3) Emissions < 10 mg/nm 3 are frequently achieved Relative SCA Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 13 Information contained in this document is ESP Separation Efficiency dm/dlog(dp) [mg/nm^3) 3 ] Before ESP 250 After ESP ,01 0, Aerodynamic Diameter [ µm] Bimodal particle distribution 1,0 160 Separation Efficiency 0,5 SMPS APS 40 Massdistribution 0,0 0 0,01 0, Aerodynamic Diameter [µm] ESP separation efficiency Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 14 Information contained in this document is 7

8 ESP Mechanical & Electrical upgrade Some measures: Mechanical Align the electrode distances or replace internals Secure optimal gas flow distribution Reduce sneakage above the electrodes and in the hopper Upgrade rapping system Electrical Other Improve ESP controller Improve energy supply SO 2 or NH 3 Conditioning Extension of one field Add one field Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 15 Information contained in this document is Gas sneakage effect Inlet dust concentration = mg/m3 Gas flow % Emission mg/nm3 99,9 % 10 0,1% Outlet dust concentration Active area = 9,99 mg/nm 3 Sneakage area = 50,00 mg/nm 3 Total = 60 mg/nm 3 Side view Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 16 Information contained in this document is 8

9 EPIC III The cellular ESP field controller each bus section is individual Energisation Spark control SemiPulse EPOQ Algorithm Electrode cleaning Rapper control PCR - Power Control Rapping Other Alarm handling Opacity optimization Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 17 Information contained in this document is Efficiency Improvements with EPIC & PCR Emission (mg/m3n) Emission with old co with use of intermitt energization. Emission with EPIC s with use of EPOQ an PCR software. 0 A B C D E Plant Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 18 Information contained in this document is 9

10 Ripple Difference Between SIR and Conventional T/R Peak kv kv 80 SIR ESP Voltage kv Spark level ( ) Conventional T/R Valley kv S Conventional T/R With SIR ESP Current ma Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 19 Information contained in this document is No. of SIRs by Application & corresponding SIR emissions (2004) Relative emission (%) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Coal Baseline - Emission with conventional T/Rs = 100% Soda WESP Cement Waste BiomassGlass Recove ry Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 20 Information contained in this document is Others SIR emissio range No SIRs No. ESPs Total: SIR at 318 plants ( MWe) 10

11 Fabric filter High removal efficiency dust emissions in the range of 5 mg/nm 3 occasionally levels down to 0.1 mg/nm 3 normally 99.9 % or more of the inlet particulate matter also for submicron-sized particles. Collection efficiency is not markedly affected by changes in : flue gas chemical composition dust loadings swings in boiler operating conditions and loads flue gas temperature Dual capacity of particulate control device and highly efficient chemical reactor for absorption of gaseous components. Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 21 Information contained in this document is Sectional overview of Sunagawa FF Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 22 Information contained in this document is 11

12 EP FF conversion procedure Bag plate under construction Pressure tank under construction Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 23 Information contained in this document is Agenda 1st topic 2nd topic 3rd topic 4th topic 5th topic 6th topic Introduction Fuel flexibility Regulations Particulate / Heavy metals Acid gases Summary & Conclusion Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 24 Information contained in this document is 12

13 Some factors affecting acid gas abatement Type of system Dry Absorption System Semidry Absorption System Wet System Removal efficiency is dependent on Type of reagent (quick lime, slaked lime, bicarbonate) Operating temperature (lower temperature gives higher removal) Relative humidity (higher RH gives higher removal) End Product Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 25 Information contained in this document is Reagents Limestone used in an FB boiler is converted to burnt lime, which can be used in a NID system Quick Lime is used in the NID. The NID hydrator creates an efficient high surface area lime Slaked lime is used in the Dry or NID systems Pore volume 0,08 0,1 cm 3 /g BET surface m 2 /g Sorbacal is used in the Dry or NID systems Pore volume 0,2 cm 3 /g BET surface 40 m 2 /g Bicarbonate temperature range C. Less sensitive to variations in RH. Needs to be milled before injection. SO 2 removal is not dependant on HCl in flue gas. Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 26 Information contained in this document is 13

14 Lime chemistry Sulphur reactions Ca(OH) 2 + SO 2 CaSO 3 *1/2 H 2 O + 1/2 H 2 O CaSO 3 + 1/2 O 2 CaSO 4 Chloride reactions Ca(OH) 2 + HCl (g) CaCl H 2 O (g) Ca(OH) 2 + HCl (g) CaOHCl + H 2 O (g) Combined reactions CaOHCl + SO 2 + 1/2 H 2 O CaSO 3 *1/2 H 2 O + HCl (g) Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 27 Information contained in this document is Dry Absorption System (DAS) Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 28 Information contained in this document is 14

15 Söderenergi Fabric Filter Boiler Condenser H 2 O ID Fan To ash silo To water treatment Lime Bicarbonate Activated Carbon Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 29 Information contained in this document is Combined system dry Ferrara, Italy Flue gas DAS-L DAS-B SCR Stack Lime AC Recirc. Bicarbonate Ammonia Steam EP-Lime EP-BC Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 30 Information contained in this document is 15

16 Semi Dry Absorption System (NID) Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 31 Information contained in this document is NID Mixer/Hydrator Recycle H2O CaO Hydrator Dispersion Plate (inside the Reactor) Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 32 Information contained in this document is Mixer 16

17 Combined Systems Jönköping, Sweden Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 33 Information contained in this document is Agenda 1st topic 2nd topic 3rd topic 4th topic 5th topic 6th topic Introduction Fuel flexibility Regulations Particulate / Heavy metals Acid gases Summary & Conclusion Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 34 Information contained in this document is 17

18 Summary & Conclusions Several options are available to improve the performance of existing plants: Particulate removal ESP upgrade Mechanical Electrical (EPIC and SIR) ESP to FF conversion Acid gases, mercury and dioxin Change of lime to high surface type Change to bicarbonate Introduce activated carbon Add one filter to a dry scrubber Add a wet scrubber Presentation ALSTOM title - 26/01/2010 All rights -reserved. P 35 Information contained in this document is 18