Research on small-scale biomass gasification in entrained flow and fluidized bed technology for biofuel production

Transcription

1 Institute for Energy Systems Department of Mechanical Engineering Technical University of Munich Research on small-scale biomass gasification in entrained flow and fluidized bed technology for biofuel production Sebastian Fendt, Felix Fischer, Reinhard Seiser, Michael Long, Hartmut Spliethoff TCS Symposium on Thermal and Catalytic Sciences for Biofuels and Biobased Products Chapel Hill, North Carolina November 2, 2016 submission # 2148

2 Institute for Energy Systems, TUM Prof. Hartmut Spliethoff Located at the TUM Campus Garching, north of Munich Campus Garching: 6000 employees, students Department of Mechanical Engineering IES-Staff: ~ 55 employees (35 PhD students, 3 Postdocs) Mission: Efficient and low emission fossil and renewable power generation 2

3 Institute for Energy Systems, TUM Structure and teaching Head of Institute: Spliethoff, Hartmut, Prof. Dr.-Ing. Supervisors: Gleis, Stephan, Dr.-Ing. Wieland, Christoph, Dr.-Ing. Vandersickel Annelies, Dr.-Ing. Fendt, Sebastian, Dipl.-Ing. Staff: ( ) 55 Employees 37 PhD students 4 Postdocs Teaching: Variety of lectures and laboratory courses, field trips and seminars Term paper, final theses and job offers for students at the Institute M.Sc. Power Engineering Staff Publications Dissertations

4 Institute for Energy Systems, TUM Research and technology areas Research / Technology areas Combustion Gasification Evaporation and therm. cycles Therm. & chem. storage Power generation Biomass and waste Waste heat utilization Fossil fuels CO 2 separation Oxy-fuel Slagging / fouling Emissions Fuel pre-treatment Energy from waste Deposition Corrosion Emissions IGCC (CO 2 -sep. and polygen.) Char conversion Ash behaviour Trace elements Fuel pre-treatment Fluidized bed Entrained flow Gas treatment SOFC Highly flexible cycles Heat transfer in supercritical evaporation (dyn.) Organic Rankine Cycle District heating (dyn.) Organic Rankine Diesel Combined Geothermal cycles Solar thermal CO 2 utilisation (CCU) PtX concepts Thermo-chem. storage CO 2 utilisation (CCU) Biomass-to-Gas (BtG/BtL) Thermo-chem. Storage Pumped heat energy storage CHP, Energy scenarios, Process simulations System studies and optimization, integrated concepts 4

5 BaCaTeC Project: Evaluation and development of measurement techniques for biomass gasification and synthesis gas upgrading processes Partners: TUM (Prof. H. Spliethoff) UCSD (Dr. R. Seiser) Research: Biomass utilization through gasification and subsequent synthesis gas utilization Gas upgrading into highly valuable liquid and gaseous products (e.g. SNG, Methanol, DME, FT-fuel) Challenges: scale-up as well as impurities in the product gas like unsaturated hydrocarbons, tars and (organic) sulfur species. Aims: Increase technological maturity of the conversion process, conducting joint test campaigns on pilot- and bench-scale plants. Optimize measurement techniques (e.g. SPA), gas clean-up methods, catalysts handling and innovative utilization concepts (e.g. SOFCs). 5

6 BaCaTeC Project: Evaluation and development of measurement techniques for biomass gasification and synthesis gas upgrading processes Partners: TUM (Prof. H. Spliethoff) UCSD (Dr. R. Seiser) Presentation Research: Biomass utilization through gasification and subsequent synthesis gas utilization Gas upgrading into highly valuable liquid and gaseous products (e.g. SNG, Methanol, DME, FT-fuel) Source: R. Seiser,

7 Introduction Motivation for energetic utilization of biomass Transition (not only in GER) from fossil to renewable Energy scenario 2050*: decrease of PEC to ~7000 PJ, with a share of 23% coming from biomass Utilization of little-used biomass resources (like agricultural residues, straw, green waste, landscape preservation material, forest residues) Overcome limitations and problems caused by the utilization of these fuels (fuel pre-treatment like HTC and torrefaction, efficiencies, conversion, emissions and tars) Gasification shows highest potential efficiencies (for electrical power from biomass) Flexible production of chemicals, fuels and power/heat Also: decrease energy dependency Small-scale (decentralized) units Biomass gasification and pre-treatment * Germany Sources: AEBIOM Statistical Report 2016; Biermann, 2015; FNR,

8 Biomass gasification Gasification technologies - overview 8

9 Biomass gasification Entrained flow vs. fluidized bed gasification - Particle size - Temperature - Residence time Fluidized bed gasification Entrained flow gasification Source: Spliethoff,

10 Biomass gasification Fluidized bed gasification technologies State-of-the-art in Europe: Allothermal Fast Internally Circulating Fluidized Bed Gasifiers (FICFB) Data from: R. Rauch, 2016; C. Aichering,

11 Biomass gasification Entrained flow gasification technologies Well-known technology from coal gasification, but no commercial biomass application European R&D activities: Bioliq, PEBG (SP ETC), TUM, Sources: Weiland, 2015, Wang, X. Z. (2014) 11

12 Entrained flow vs. fluidized bed gasification Review: Technologies and important parameters Entrained flow gasification: Well-known technology for coal gasification but almost no experience for biomass No simple scale-down of coal gasifiers! Challenges: Fuel pre-treatment (HTC, torrefaction) Oxygen supply (ASU, electrolysis?) Ash behavior (slagging, non-slagging) Conversion / kinetics Fluidized bed gasification: Well-known technology in small- to medium-scale (500kW-50MW) applications Agglomeration behavior has to be taken care of (Ca, K and Na in the fuel/ash) Most concepts use a circulating bed configuration (e.g. FICFB) Examples: FICFB Güssing (AT), MILENA (NL), Forster Wheeler (SE), Heatpipe Reformer (GER) Challenges: Complete carbon conversion (average ~ 90%) high cold gas efficiency Formation of organic impurities (tars) in the product gas (2-20 g/m 3 ) condensation, plugging Pressurized operation feeding system Tremel et al. 2013, DOI: /j.enconman

13 Test facilities for biomass utilization Entrained flow and fluidized bed as well as fuel pre-treatment Hydrothermal carbonization unit for feedstock pre-treatment Specs: 50 kg dry /batch 50 bar 250 C Allothermal fluidized bed gasification coupled to gas upgrading system Specs: 5 kw 5 bar 900 C Autothermal entrained flow gasifier Specs: 100 kw 5 bar 1500 C 13

14 Biomass pre-treatment Hydrothermal carbonization (HTC) Increasing carbonization with increasing T Energy content, density and brittleness of the biomass increase Product: energy dense, hydrophobic and easy to mill material Dehydration and decarboxylation reactions of the lignin structure Cellulose and small parts of the lignin structure dissolve in the solution H/C 1,8 1,6 1,4 1,2 1,0 0,8 0,0 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 2,0 O/C REnC (dry basis) Yield (dry basis) T / C 190,0 200,0 210,0 220,0 230,0 240,0 250,0 260,0 80 Relative Energy Change 1,5 1,0 = 3h c = 10 g/100 ml Yield / % 0, Temperature / C 14

15 Entrained flow gasification Test rig for autothermal biomass gasification (100kW) Test rig data: Operation: autothermal Temperature: up to 1500 C Pressure: 0 to 5 barg Fuel input: 100 kw (+/- 25 %) Dosing system: pneumatic Gasif. media: Air, O 2, H 2 O, CO 2 Operation time: ~10 h Burner Pressurized vessel Product gas filter Goals: Realistic conditions (no electrical heating) Investigation of cold gas efficiency, gas quality, ash melting behavior, tars, Sampling probe Quench water collection vessel Feeding system 15

16 Entrained flow gasification Air-blown entrained flow gasification of bio-coal from hydrothermal carbonization Source: Briesemeister et al., 2016, DOI: /ceat

17 Entrained flow gasification Air-blown entrained flow gasification of bio-coal from hydrothermal carbonization Source: Briesemeister et al., 2016, DOI: /ceat

18 Entrained flow gasification Air-blown entrained flow gasification - feedstock HTC-coal from green waste Rhenish lignite Corncob (raw) HTC-coal from compost Source: Briesemeister, 2016, Project report 18

19 Fluidized bed gasification For the production of Synthetic Natural Gas (SNG) the test rig incl. hot gas cleaning 19

20 Experimental results Combined biomass gasification with hot gas cleaning and upgrading to SNG Permanent gas components (4-hour-rhythm between different gas measurement locations) Results refer to dry gas without nitrogen dilution Mean deviations between experimental results and simulations within 2.5% However: shift in gas composition over time (starting after ~ 75h) Degradation 20

21 Hot gas cleaning Tars and hydrocarbons 1.5 3% (C 2 -C 5 ) (N 2 -free, dry gas) Ethene with >1% highest concentration Very low HCs contents after tar reforming 7 11 g/m 3 after gasifier during normal operation Good conversion of tars (>>90% for all substances bevor and after catalytic tar reforming 21

22 Power generation in SOFCs with biogenic syngas Coupling of a biomass gasifier with a SOFC Understanding of mechanisms and reduction of degradation and poisoning Different levels of contaminants (H 2 S, tars) Step-wise increase of contaminant 22

23 Coupling of power and natural gas grid Combination of Power-to-Gas and Biomass-to-Gas concept Combined system with electrolysis unit, whereas O 2 is added for partial-oxidation in the tar reformer and for post-combustion (membrane). H 2 is added for methanation (amount depending on carbon formation or optimized operation (SN=3) Efficiency increase but difficult economics today!! 23

24 Thank you for the attention!!! and thanks to the team at TUM, to our collaborators at UCSD and thanks for funding: Contact: