Drop in potential of upgraded fuels produced at pilot scale via hydrothermal liquefaction of different biomass feedstocks Patrick Biller, Jinlong Yu, René Madsen, Ib Johannsen, Marianne Glasius INSTITUTE OF ADVANCED STUDIES
Pressure (bar) Carbonisation Liquefaction HYDROTHERMAL PROCESSING 400 Biomass feedstock is pressure cooked in hot-compressed water No dry feedstock required 350 300 250 (liquid) Supercritical Gasification Mimics natural fossil fuel creation coal, oil, gas HTL can convert whole biomass to a high energy density biocrude One of the main advantages of HTL is the high flexibility of feedstocks and products. 200 150 100 50 0 Critical point (vapour) 0 100 200 300 400 500 600 700 Temperature ( C) Water-phase diagram INSTITUTE OF ADVANCED STUDIES
HTL CONCEPT INSTITUTE OF ADVANCED STUDIES
HTL CONCEPT INSTITUTE OF ADVANCED STUDIES
TARGET FUELS Gasoline B.P. <190 C 17% n-alkanes 32% branched alkanes 5% cyclo alkanes 30% aromatics C5-C10 Renewable alternative: Ethanol Kerosene B.P. 190-290 C 70-85% paraffins <25% aromatics <5% olefins C8-C16 Renewable alternative: FT, HEFA, Pyrolysis, AtJ Diesel B.P. 200-340 C 75% paraffins 25% aromatics C10-C22 Renewable alternative: HDO lipids, FAME INSTITUTE OF ADVANCED STUDIES
HTL REACTORS 4 different continuous HTL reactors were used: 2 at Aarhus University (Denmark) 1 at Aalborg University (Denmark) 1 at Leeds University (UK) continuous HTL lab scale continuous HTL bench scale continuous HTL pilot scale Leeds Aarhus Aalborg Aarhus INSTITUTE OF ADVANCED STUDIES
Feedstock: DDGS Relatively small capacity, max 34 L/day High heating rate due to induction heating (17 C/s) Great for screening different biomasses, catalysts etc. Custom built dual piston pump No heat recovery 350 C, 15 min residence time, 8mL/min INSTITUTE OF ADVANCED STUDIES
AALBORG / STEEPER CBS 1 UNIT 100 kg feed barrel, 5-30 kg/h capacity Runs at supercritical conditions (~400 C, 300 bar) Hydrofraction technology by Steeper Energy Feedstock: Aspen Wood 1. Hoffmann, J., Bio-oil Production-Process Optimization and Product Quality. 2013, Videnbasen for Aalborg University 2. Pedersen, T.H., HydroThermal Liquefaction of Biomass and Model Compounds. 2016. INSTITUTE OF ADVANCED STUDIES
Feedstock: Miscanthus Capacity up to 100 L/h Largest academic HTL reactor in the world Designed for scalability and heat recovery (~80%) Innovative pressure release system Biomass pre-treatment/extrusion onsite Can handle relatively big particles ~10mm 350 C, 25 min residence time INSTITUTE OF ADVANCED STUDIES
REACTOR How to handle the need for long residence time and thus low flow? Non newtonian (thixotropic) biomass, low heat transfer efficiency, fouling Time Average flowrate Local flowrate Position in reactor Oscillation flow 120 m INSTITUTE OF ADVANCED STUDIES
UPGRADING METHODOLOGY Commercial catalysts form Haldor Topsøe NiW/Al 2 O 3, NiMo/Al 2 O 3 with high and high loadings of NiMo, (PN: TK-951, TK-341 and TK-351) No pre-sulphiding or reduction used 500 ml Parr batch reactor, stirred 100 g of bio-crude each experiment Catalyst screening & optimisation study on wood bio-crude 350 C, varying residence time, H2 pressure and cat loading INSTITUTE OF ADVANCED STUDIES
FEEDSTOCK Four different feedstocks under investigation Diverse biochemical composition DDGS, by-product form bioethanol industry Lignin Carbs Protein Lipids 100% 80% 60% 40% 20% Microalgae=Chlorella vulgaris 0% Microalgae DDGS Miscanthus Aspen Wood INSTITUTE OF ADVANCED STUDIES
HTL RESULTS Proteinaceous feedstock have high N content O content highest for Miscanthus (high carbohydrate content) Catalytic upgrading aim to reduce O and N and viscosity Bio-crude Yield (%) Microalgae DDGS Miscanthus Aspen Wood ~40 ~40 ~27 ~42 C 72.8 70.3 73.6 80.5 H 9.4 9.0 7.2 8.4 N 6.0 5.4 1.0 0.4 O 11.1 14.8 18.0 10.7 HHV (MJ/kg) 36.1 34.1 32.0 37.4 INSTITUTE OF ADVANCED STUDIES
CAT SCREENING No catalyst resulted in predominantly char production All catalysts have a huge effect compared to control Upgraded oil yields increase from 17 to ~70% Yields follow NiMo high loading > low loading > NiW Significant losses due to sample work up INSTITUTE OF ADVANCED STUDIES
EFFECT OF CATALYST Highest yield catalyst also provided best HDO Viscosity reduced drastically, free flowing oil Optimum conditions result in 0.7 % O, 44 MJ/kg Elemental analysis, wt.% Experimental HHV Viscosity conditions C H N O* MJ/kg cp at RT Bio-crude 80.5 8.4 0.4 10.7 37.36 2.10x10 5 No catalyst 82.7 8.6 0.5 8.1 38.9 n.a. NiW, 2h, 75bar, 10% 84.1 8.4 0.6 6.9 39.3 981 NiMo-LL, 2h, 75bar, 86.5 9.1 0.5 3.8 41.8 33 10% NiMo-HL, 2h, 75bar, 10% 87.8 9.2 0.6 2.4 42.6 62 NiMo-HL, 4h, 100bar, 10% 89.5 9.6 0.5 0.7 43.7 16 INSTITUTE OF ADVANCED STUDIES
(%) HDO CARBON AND ENERGY BALANCE HDO upgrading recovers the majority of carbon in the upgraded fuel. 110 100 Microalgae DDGS Wood 90 Energy recovery also very good but H 2 added to reaction. 80 Miscanthus data not available due to too high viscosity of upgraded fuel. 70 60 50 Oil yield (wt.%) Carbon recovery (%) Energy recovery (%) INSTITUTE OF ADVANCED STUDIES
HDO RESULTS Upgrading conditions only optimised for wood Different bio-crudes could work better at different conditions/ catalysts Nitrogen removal not very effective Miscanthus sample only showed minor upgrading(o=18% O=11%) HHV comparable to fossil crude HDO of wood approaches refinery ready specs Microalgae DDGS Miscanthus Aspen Wood HDO Yield (%) 93 80? 78 C 80.5 81.7 80.6 87.8 H 10.5 9.9 7.3 9.2 N 4.7 5.7 0.9 0.6 O 4.2 2.2 11.2 2.4 HHV (MJ/kg) 41.5 41.5 35.6 42.4 INSTITUTE OF ADVANCED STUDIES
DDGS CRUDE Bio-crude Large amounts of N-containing compounds, pyrazines, pyrroles in crude Lots of fatty acids due to lipid content DDGS HDO oil less complex Large abundance of alkanes (Max chain length C15-C18) HDO Bio-crude Aromatic HCs; toluene, ethyl-benzene in gasoline range Some O and N compounds remaining INSTITUTE OF ADVANCED STUDIES
WOOD CRUDE Bio-crude Wood crude composition less complex Large abundance of aromatics and PAH Retene ~2.5 wt.% Some phenolics present HDO wood crude still shows a lot of PAH Surprisingly large amount of alkanes Maximum at C17 Only O containing compounds detected are phenols e.g. Phenol=2500pm; 4-ethyl-Phenol =3700ppm HDO Bio-crude INSTITUTE OF ADVANCED STUDIES
MISCANTHUS Bio-crude HDO of Miscanthus not successful High amounts of phenolics in crude Phenols are more difficult to hydrotreat HDO Bio-crude Appearance of some gasoline range HCs Small amounts of C15-C17 (~1000ppm total) INSTITUTE OF ADVANCED STUDIES
MICROALGAE Bio-crude Algae crude is highly complex with lots of N containing compounds, fatty acids, fatty acid amides Algae HDO shows large abundance of alkanes HDO Bio-crude C11-C18, kerosene range All small N- containing compound HDN Aromatics only in gasoline range Some remaining nitrile and amide compounds after HDO INSTITUTE OF ADVANCED STUDIES
MICROALGAE HDO 405 C all remaining nitriles and amides removed at 405 C Primarily paraffinic HCs present in kerosene range Some aromatic HC in gasoline range higher temperature only tested for algae Results in reduced yields but less O (1.5%) Similar effects on other feedstocks? INSTITUTE OF ADVANCED STUDIES
SIM-DIS All crudes exhibit large amount high B.P material (>50%) Heavy fraction only reduced to around 40% after HDO higher HDO temp. should help Upgraded fuels show largest abundance of kerosene fraction 405 C microalgae heavies reduced to 25% INSTITUTE OF ADVANCED STUDIES
CONCLUSIONS Good HDO performance even at mild conditions of 350ºC. Optimising conditions led to <1% oxygen for wood bio-crude Miscanthus feedstock problematic more phenolics High protein less problematic, small N-containing compounds are efficiently HDN ed HTL is versatile and can produce aliphatic and aromatic HCs even form non-lipid feedstocks Feedstock mixing and optimisation offers the possibility of tailoring final fuel composition INSTITUTE OF ADVANCED STUDIES
Thank you! pbiller@aias.au.dk The AIAS-COFUND Fellowship Programme is funded by: European Union s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 609033. INSTITUTE OF ADVANCED STUDIES
CRUDE VS HDO ~60 authentic standards used for quantification Ketones are efficiently HDO N-containing compounds also HDO Phenols are more difficult to HDO and additional phenolics can appear from cracking of non-gc- amenable fraction during HDO DDGS & algae higher aliphatic / aromatic Wood 50-50 aromatic / aliphatic INSTITUTE OF ADVANCED STUDIES
ALKANE CHAIN LENGHTS INSTITUTE OF ADVANCED STUDIES
ALKANE CHAIN LENGTHS INSTITUTE OF ADVANCED STUDIES