Chemical Looping Combustion of biomass fate of ash forming elements

Transcription

1 IX Liekkipäivä Dipoli Chemical Looping Combustion of biomass fate of ash forming elements Jan-Erik Eriksson, Anders Brink, Maria Zevenhoven, Patrik Yrjas and Leena Hupa Åbo Akademi University, Finland Fredrik Hildor and Henrik Leion Chalmers University, Sweden

2 Negative CO 2 Nordic Flagship Project Enabling negative CO₂ emissions through the use of Chemical-Looping Combustion of biomass (Bio-CLC) Partners: Chalmers University of Technology The Bellona Foundation Sibelco Nordic AB SINTEF Energy Research SINTEF Materials and Chemistry VTT Technical Research Centre of Finland Ltd Åbo Akademi University

3 Goal Paving the way for biomass-clc Transport routes of ash forming elements Biomass ash oxygen carrier interactions Biomass ash induced corrosion risks

4 Chemical looping Fluidized bed technology Bed material Heat transfer Solid oxygen carrier (Me x O y ) Mn Fe-Ti Etc.

5 Chemical looping Fluidized bed technology Bed material Heat transfer Solid oxygen carrier (Me x O y ) Mn Fe-Ti Etc. Lyngfelt and Lindholm 2017

6 Interaction with bed material Can interaction with the bed material provide a vehicle for transport of alkali?

7 SEM: Ilmenite ore + 4 %wt K 2 CO 3 K 2 CO 3 reacts with ilmenite No K 2 CO 3 K 2 CO 3 24h, 850 C Ti Fe Ti Fe K+Ti

8 XRD: Ilmenite ore Before heat pre-treatment: Ilmenite (FeTiO₃) After heat pre-treatment Pseudobrookite (Fe 2 TiO 5 ) Ilmenite 950 C Pseudobrookite After heat treatment + K 2 CO 3 Pseudobrookite (Fe 2 TiO 5 ) K 2 CO C KTi 8 O 16.5 K 2.3 Fe 2.3 Ti 5.7 O 16 Also K-Ti-Fe

9 SEM: Manganese ore+ 4%wt K 2 CO 3 K 2 CO 3 does not react with manganese No K 2 CO 3 K 2 CO 3 24h, 850 C K, Ca, Al, Si Mn K Ca K, Ca, Al, Si Mn

10 Interaction with bed material Are bed materials prone to agglomeration if biomass is used in CLC?

11 Experimental set-up Temperature profile logged Feeding port for salts Pressure measurement In the pre-heater At the top of the reactor Instrumental and exhaust section Combustion section 150 mesh net Tube furnace Pre-heater Primary air inlet

12 Results: defluidization

13 Ilmenite with KCl, 1.5 g/10 min, 850 C Only Fe and Ti in bed partices Most KCl volatalizes High KCl feed needed to agglomeration Ti Cl Fe K

14 Ilmenite with K 2 CO 3, 1.5 g/10 min 950 C Fresh bed material Agglomerated bed material

15 Ilmenite with KH 2 PO 4, 0.5 g/10 min 950 C Ti Fe Only Fe and Ti in bed particles The neck between the bed particles contains K, P some traces of Fe P K 15/21

16 Biomass induced corrosion What requirements do we have on (metallic) heat transfer surfaces?

17 Chemical looping Adad et al, Chemical Engineering Journal 310 (2017)

18 Candidate materials

19 Candidate materials for air reactor, material temperature 700 C

20 Candidate materials for fuel reactor, material temperature 550 C

21 Fireside corrosion laboratory testing 1. Test specimens cut from super-heater tubes (2 x 2 x0.5 cm) 2. Surface ground with 600SiC and eventually covered with synthetic ash h exposure in test atmosphere/temperature 4. Preparation of sample s cross-section 5. SEM/EDX (oxide /corrosion layer thickness, corrosion product composition etc.) Final: Results analysis

22 Corrosion layer thickness Corrosion layer thickness determined using SEM images Semi-automatic image analysis Mean, median, most occurring and maximum layer thickness determined

23 Test matrix Gas composition fuel reactor: 50 vol-% CO 2, 50 vol-% H 2 O +500 ppm HCl air reactor: dry air +1 vol-% O 2 Deposit No deposit Ilmenite Ilmenite with potassium KCl

24 Results air reactor

25 Results air reactor

26 Results fuel reactor 50% CO % H 2 O

27 Results oxy-polishing 49.5% CO % H 2 O+1% O

28 Conclusions Typical steam parameters for biomass combustion seems possible also in the fuel reactor Corrosion only detected using carbon steels Fuels containing K and Cl most risky Small amounts of O 2 affects the corrosion rate

29 Acknowledgement This work is part of the Nordic Flagship project Enabling negative CO2 emissions in the Nordic energy system through the use of Chemical-Looping Combustion of biomass (Bio- CLC) financed by the Nordic Energy Research. The financial support by Åbo Akademi University is acknowledged