Biocoke for the cupola furnace

Transkript

1 Biocoke for the cupola furnace , Saulo H. Freitas Seabra da Rocha, Peter Quicker

2 Lehr- und Forschungsgebiet Technologie der Energierohstoffe research fields production and conversion technologies for solid fuels (fossil, renewable and secondary energy sources) focus on thermochemical processes equipment laboratory for fuel characterization technical hall (rotary kiln reactor, biomass gasifier, test burning chamber, biodigesters) course of studies Mineral Resources Engineering Waste Management Environmental Engineering 2

3 Biocoke for the cupola furnace Motivation Project overview Selection of raw materials Carbonizing experiments Batch retorts Rotary kiln reactor Briquetting Practical experiments 3

4 Motivation CO 2 emissions of German cupola furnaces in 2008 approx. 1.5 mill. t/a dependency of the German foundry industry on coke imports price fluctuations dominate the coke market coke price [ /t] realized in cooperation with financially supported by 4

5 Project overview biocoke pyrolysis Pyrolysegas gas briquettes Start-up Anfahrbrenner burner combustion Brennkammer chamber Primärluft primary Sekundärluft secondary heating Heizgas air air gas agglomeration crushing Abgas exhaust gas Pyrolyse-Drehrohr rotary kiln v 1 dust blowing slag iron 5

6 Project overview Objectives development of foundry coke substitutes based on biomass residues: - CO 2 neutral - cost-effective - no competition with food crops and other renewable resources Work packages: selection of raw materials - costs, availability, composition development of suitable alternative fuels - Pyrolysis - Agglomeration & tests with binding materials fuel production in a pilot plant proving experiments on industrial cupola furnaces 6

7 Selection of raw materials evaluation criteria: sustainable acquisition - no competition with food crops! favorable composition - ash, N, P, S, Cl sufficient availability - approx. 200, ,000 t/a low price - biocoke production < 300 /t preferential local biomass types 7

8 Selection of raw materials availability and cost analyses (selection) biomass availability costs rape straw 14.6 mill. t /t wheat straw 14.1 mill. t /t waste wood(ai-aiv) 7.8 mill. t 0 40 /t forest residues 7.6 mill. t /t landscaping residues 1.8 mill. t /t bark 0.1 mill. t 20 /stere olive kernels 1.2 mill. t ES, IT, GR 54 /t ES almond shells 0.07 mill. t EU15 n.s. hazelnut shells 0.3 mill. t TR n.s. oil palm kernel shells 4.3 mill. t MAL approx. 100 /t 8 Quelle: EUROSTAT, Nourouzi 2009, Demirbas 1998

9 Selection of raw materials 15 biomass types for the batch carbonizing experiments - rape straw - rye straw - wheat straw - hazelnut shells - coconut shells - oil palm kernel shells - waste wood (AI, AI-III, AIV) - green cut - landscaping residues - bark - forest residues - digested residue 9

10 Carbonizing experiments batch retorts 10

11 Carbonizing experiments batch retorts Biocoke produced in the lab waste wood A IV rape straw briquettes hazelnut shells 11

12 Carbonizing experiments batch retorts Thermogravimetic analyses pre-drying crushing heating rate: 8,5 C/m 12

13 Availabilioty [mill.. T] Carbonizing experiments rotary kiln reactor selected raw materials bark waste wood AI forest residue rape straw coconut shells /m³ 25 /t /t 22 /t 100 /t 13

14 Carbonizing experiments rotary kiln reactor bark 100% 51,4 % C pyrolysis gas furnace wall temperature: 700 C input approx. 0,8 kg/h char yield: % biocoke approx. 34% % C 14

15 Carbonizing experiments rotary kiln reactor biocoke from bark 15

16 Biocokes in comparison to foundry coke Material A [%] VM [%] C fix [%] C [%] H [%] N [%] S [%] Cl [%] LHV [MJ/kg] foundry coke rape straw raw char bark raw <0.1 < char forest residues raw <0.1 < char waste wood A1 raw <0.1 < char coconut shells raw < char <

17 Carbonizing experiments rotary kiln reactor product yields weight-% rape straw coconut shells waste wood AI forest residue bark yield [%] raw material char oil gas ash char[%] bark waste wood A I forest residue rape straw coconut shells gas oil char 17

18 Briquetting Testing procedures for briquettes Tensile splitting strength Compressive strength at room temperature High temperature mechanical strength 18

19 Testing the briquettes bark biocoke briquettes tensile splitting strength [MPa] RC= refractory cement AP= aluminium phosphate PC= Portland cement 19

20 Testing the briquettes binding agent: 12 % molasses, 12 % refractory cement tensile splitting strength [MPa] 20

21 flue Practical experiments biomass approx. 180 kg/h Biocoke pilot plant reburning rotary kiln reactor T= C p=1,0-1,1 bar exhaust gas ca m³/h* char discharge dust separator * at operating pressure char approx. 36 kg/h char dust approx. 1,5 kg/h 21

22 Practical experiments Installation of the pilot plant 22

23 Practical experiments Rotary kiln reactor of the pilot plant 23

24 Practical experiments feedstock materials: pig iron steel scrap loop materials alloying elements limestone biocoke as briquettes environment metallurgy measured parameters: exhaust gas and dust composition before the filtration clean gas and dust composition odor iron bracket temperature melting capacity Chemical composition of the iron bracket thermical analysis slag composition and quantity Examintion of the mechanical parameters and structure biocoke as dust 24

25 Conclusion biomass residues show a great potential for the substitution of conventional fuels in industrial processes (e.g. cast iron production) high coke prices and the purpose of CO 2 emissions saving make biocoke more attractive carbonized biomass manifest similar characteristics to foundry coke in its composition scheduled experiments in a pilot-scale rotary kiln reactor will demonstrate the advantage of this pyrolysis technology 25

26 thank you very much for your attention! Contact: Dipl.-Ing. Guillermo Peña Unit of Technology of Fuels Wuellnerstrasse Aachen pena@teer.rwth-aachen.de 26