Safe co-combustion and extended use of biomass and biowaste in FB s with accepted emissions

Size: px

Start display at page:

Download "Safe co-combustion and extended use of biomass and biowaste in FB s with accepted emissions"

Antony Mathews
9 years ago
Views:

1 Safe co-combustion and extended use of biomass and biowaste in FB s with accepted emissions ENK5-CT

2 2 Background Controlled Em issions NEW CO-INCINERATION DIRECTIVE OF THE COMMISSION Safe combustion process in F B E fficie n t monitoring and emission control TOOLS C om bustion re a c to rs Advanced on-line analysers M od ellin g TOOLS Com bustion re a cto rs Advanced on-line analysers M odelling Landfill COMBUSTIBLE W ASTE Industrial waste House hold waste A g ricu ltu ra l w a ste M a d co w

Advanced on-line analysers M od ellin g TOOLS Com bustion re a cto rs Advanced on-line analysers M

3 3 VTT TECHNICAL RESEARCH CENTRE OF FINLAND Partnership (VTT Co-ordinated) 1. Technical Research Centre of Finland, Processes FIN 2. Kvaerner Power OY FIN 3. Offenbach Power Company GER 4. Dekati Measurements OY FIN 5. Institute of Process Engineering and Power Plant Technology, University of Stuttgart GER 6. Technical University Wroclaw (<-> Turow) PL 7. Emissions-Reduzierungs-Concepte GmbH GER 8. Thermal Power Engineering, Technishe Universiteit Delft NL 9. W.K. Crone B.V. NL

Dekati Measurements OY FIN 5. Institute of Process Engineering and Power Plant Technology, University of Stuttgart GER 6.

4 4 Workpackages (EU funding 1,5 million ) WP1 Fuel delivery, treatment and analysis responsible partner 1 WP2 Creating basis to replace part of brown coal with biomass waste in large Polish CFB plants, responsible partner 5 WP3 Creating basis to replace higher share of coal with MBM in a CFB plant responsible partner 1 WP4 Improving calculation tools and biomass fuel flexibility in small BFB plants for Eastern European markets responsible partner 8 WP5 Combustion problem solution by chemicals responsible partner 7 WP6 Means to reach high share of household waste in FB s and developing an alarm sensor of corrosive flue gases for FB combustion responsible partner 1 WP7 Management, implementation, reporting responsible partner 1

fuel flexibility in small BFB plants for Eastern European markets responsible partner 8 WP5 Combustion problem solution by chemicals responsible partner 7 WP6 Means to reach high

5 WP3 Best coal for MBM Selection of MBM and coals, OPC 0.1 MW CFB exp. VTT Tests in 100 MW CFB OPC Basis to find synergic effects Solution of operational and emission problems to 25% MBM MBM: 15->25% enb Guidelines

6 6 Thermal power plant CIRCOFLUID Offenbach Thermal power plant Year of Commissioning 1988 Thermal Capacity 80 MW Live Steam 110 t/h 535 C 115 bar Feedwater 191 C Min. Load 40 %

7 Problems were detected in EVO s CFB when MBM was co-fired with German coal Experiments in VTT s 0.1 MW CFB reactor assisted in the solution of detected problems in the CFB boiler Strong fouling High superheater corrosion rate EVO AG s 100 MW th CFB VTT s 0.1 MW th CFB

1 MW CFB reactor assisted in the solution of detected problems in

8 Elemental concentrations of selected damaged parts of the CFB plant superheaters D= deposition C= corrosion contributor D 25 % C UE2-1 UE2-2 UE3-1 UE C Na Mg Al Si P S Cl K Ca

C= corrosion contributor 9 35 30 D 25 % 20 15 C

9 10 Theory Alkali chlorides in the furnace can be destroyed by two reactions 2MCl + SO 2 + ½ O 2 + H 2 O -> M 2 SO HCl (1) (better known) * 2 MCl + Al 2 O 3 *2SiO 2 + H 2 O -> M 2 O*Al 2 O 3 *2SiO 2 + 2HCl (2) (new) * Coal can be used as a source of sulphur and aluminium silicates!

known) * 2 MCl + Al 2 O 3 *2SiO 2 + H 2 O -> M 2 O*Al 2 O 3 *2SiO 2 +

10 Composition of ash obtained at 550 C 100 % 90 % 80 % 70 % 60 % 50 % 40 % 30 % 20 % 10 % 0 % PC40M 100 M K 2 O K2O P2O5 FeO CaO SiO2 Al2O3 100 GC 80 GC 20 M 70 GC 30 M 60GC40M 100 SA 80SA20M 70SA30M 60SA40M 100PC 70PC30M % wt, in ash

11 % % % % % 8.00 % 6.00 % 4.00 % 2.00 % 0.00 % Fuel composition, wt dry basis Coals Ash 815 C Cl (x10) S (x10) K (x10) Na (x10) 100 GC 80 GC 20 M 70 GC 30 M 60GC40M 100 SA 80SA20M 70SA30M 60SA40M 100PC 70PC30M 60PC40M 7

12 13 Deposit probing from 0.1 MW CFB -> SEM analysis in Åbo Akademi University Lee side 50 o from Wind side β=50 Wind side Inorganic vapors

13 14 60% GC 0.1 MW CFB: 420 o C50 o up 30 60% SA coal 60% PC 60 SA 60 PC wt% GC 80GC20M 70GC30M 60GC40M 70SAC30M 60SAC40M 100PC 70PC30M 60PC40M 0 Cl K Na Al Si S Ca

14 15 Problem solution Advice: Please, change German coal to South Afrcan coal! Problem in German coal: High potassium contents incactivates the protective compounds in the coal ash Advantage in S.A. coal: Rich in active aluminium silicate destroying alkali chlorides before their deposition Alkali aluminium silicate dominates strongly over sulphation in alkali capture (leading to HCl formation)

15 16 CASE: GERMAN COAL AND MBM COFIRING Heat transfer surface Cl releases corrosion ALKALI CHLORIDES RISKY COMPOUNDS K-inhibited protecting compounds Low ash content MBM GERMAN COAL/ LESS PROTECTIVE COAL

16 WP6 Selection of househ.w, bark, coal: KPOY Sensor testing Dekati M Sensor development (Na,K, Cl) Dekati M 0.02 MW BFB VTT 2 MW BFB KPOY 0.1 MW CFB VTT 4 MW CFB KPOY Sensor Scale-up Scale-up Guidelines

17 18 VTT TECHNICAL RESEARCH CENTRE OF FINLAND VTT:s contribution in WP6: Experiments with mixtures of different coals and RDF RDF received as pellets from Pietarsaari Goas: - To find means to prevent Cl deposition - To get more infotrmation on Cl deposition (together with Kvaerner Power) - To get more information on mechanisms presenting Cl deposition (in co-operation with Kvaerner Power) - To participate to scale-up together with Kvaerner power RDF contained 0.65 wt% chlorine and 9 wt% ash

deposition (together with Kvaerner Power) - To get more information on mechanisms presenting Cl deposition (in co-operation

18 Working methodology Deposit sampling wt% Cl ºC wind 500ºC lee 500ºC 50º 420ºC wind 420ºC lee 420ºC 50º Flue gas analysis SEM EDS 40SAC60RDF 38PC62RDF 40RDF60B Fine fly ash share Cl mg/nm <4.02 µm In HCl Tacky deposit Inorganic vapors Fine fly ash sampling Particle analysis Cl mg/nm Particle analysis µm µm µm µm µm 0 40SAC60RDF 38PC62RDF 40RDF60B SAC60RDF 38PC62RDF 40RDF60B

0 SEM EDS 40SAC60RDF 38PC62RDF 40RDF60B Fine fly ash share Cl mg/nm3 700 600 500 400 300 200 100 <4.

19 20 Dependency between risky chlorine flow (in the fly ash) and Cl deposition Cl mg/nm <4.02 µm In HCl wt% Cl ºC wind 500ºC lee 500ºC 50º 420ºC wind 420ºC lee 420ºC 50º SAC60RDF 38PC62RDF 40RDF60B 40SAC60RDF 38PC62RDF 40RDF60B

20 21 Distribution of chlorine and potassium in fine fly ash Cl K Cl mg/nm µm µm µm µm µm K mg/nm µm µm µm µm µm 0 40SAC60RDF 38PC62RDF 40RDF60B SAC60RDF 38PC62RDF 40RDF60B

1 µm K mg/nm3 160 140 120 100 80 60 40 1.61-4.02 µm 0.64-1.61 µm 0.26-0.64 µm 0.

21 22 Distribution of chlorine and sulphur in fine fly ash Cl S Cl mg/nm µm µm µm µm µm S mg/nm µm µm µm µm µm 0 40SAC60RDF 38PC62RDF 40RDF60B 0 40SAC60RDF 38PC62RDF 40RDF60B

22 23 VTT TECHNICAL RESEARCH CENTRE OF FINLAND Hiukkasten massavirta kerrostumanäytteenottimen kohdalla Seos: SA coal 40 RDF 60 Seos: kuori 60 RDF dm/dlog(dp) [mg/nm³] dm/dlog(dp) [mg/nm³] Tiivistyneitä alkali klorideja Particle Diameter Dp [µm] Particle Diameter Dp [µm]

23 24 Esimerkki lentotuhkan raskasmetallipitoisuuksista (Direktiivin summattavat metallit) 60PC40RDF metals 60SAC40RDF metals wt% in ash fraction < to 1 1 to 8 wt% in ash fraction < to 1 1 to Mn Pb Cr Ni Cu Co As Sb V 0 Mn Pb Cr Ni Cu Co As Sb V

24 25 Sum metals in dust (Mn+Pb+Co+Cr+V+Ni+As+Sb+Cu) mg/nm3 9,0 8,0 7,0 6,0 5,0 4,0 3,0 2,0 1,0 0,0 Total metal emission limit=0.5 mg/nm 3 Measured metal emission Fly ash particle size 1 to 8 µm 0.2 to 1µm < DW 40PC40RDF20B 60PC40RDF 80SA20RDF 60SA40RDF

25 26 Conclusions RDF share can be rised up to 60% on energy basis without Cl deposition when co-fired with an with optimal coal Again: Optimal coal is rich with free aluminium silicate Sulphation was not clearly observed as a mechanism to destroy alkali chlorides New working methodology for Cl deposition study (impactor sampling from hot furnace is very demanding stage)

26 27 List of publications WP3: Aho, M. and Ferrer. E., Importance of coal ash composition in protecting the boiler against chlorine deposition during combustion of chlorine-rich biomass. Fuel 84 (2005) WP3: Ferrer, E., Aho, M., and Filipczyk, D., Solution of Superheater Related Problems in CFB During Co-Firing of a Demanding Biomass Residue by Coal Quality Optimisation. In the proceedings of VGB Workshop "Operating Experience with Fluidised Bed Firing Systems VGB Power Tech, Berlin, September p. WP6: Aho, M., and Silvennoinen, J., Preventing Chlorine Deposition on heat Transfer Surfaces with Aluminium-Silicon Rich Biomass. Fuel 83 (2004) WP6: Silvennoinen, J., Roppo, J., Nurminen, R.V., Aho, M., Vainikka, P., Ferrer, E., Co-combustion of coal, RDF and biomass- Prevention of chlorine deposition by using coal ash absorption ability. Proceedings of 18th international Conference of FB combustion. Toronto, Canada May 22-25, WP6: Ferrer, E., Aho, M., Silvennoinen, J. and Nurminen R.V. FB Combustion of refuse-derived fuel (RDF) at large portions with presence of protective coal. Fuel Processing Technology 87 (2005) WP6: Aho, M., Vainikka, P., Taipale, R., and Vesala, H., Alkali Chloride deposition problem solution with protecting fuel and simultaneous measurements with impactors, FTIR and deposit probes. In proceedings of 14th European Biomass Conference & Exhibition October 2005, Paris, France 5p. PhD Thesis: WP s 3 and 6: Academic dissertation of Mr. Eduardo Ferrer will be arranged in the University of Zaragoza, Spain in 2006.

27 28 VTT TECHNICAL RESEARCH CENTRE OF FINLAND Staff in VTT Operators: Kimmo Roiha & Kimmo Puolamäki, Pertti Frilander FB developing engineer: Kari Paakkinen Researchers: Martti Aho, Eduardo Ferrer, Raili Taipale, Pasi Vainikka from VTT Jyväskylä, Hannu Vesala from VTT Espoo Acknowdeglements: * European Commission for funding 50% of VTT s costs * TEKES for funding 20% of VTT s costs * Åbo Akademi/ Proces Chemistry for conducting deposit analysis

New and improved slagging and corrosion control techniques for biomass firing. Martti Aho IV Liekkipäivä 23.01.2008

New and improved slagging and corrosion control techniques for biomass firing IV Liekkipäivä 23.01.2008 Organisation of the research project t Research organisations:vtt (Co ordinaator) Åbo Akademi University