Acid Hydrolysis of Hemicelluloses in a Continuous Reactor

Transcription

1 Acid Hydrolysis of Hemicelluloses in a Continuous Reactor Andrea Pérez Nebreda POKE Researchers network Summerschool in Saarema, Kuressaare

2 Outline 1. Introduction Biorefineries 2. Aim of the Project 3. Hydrolysis of Hemicelluloses 4. Why continuous 5. Galactoglucomannan (GGM) 6. Hydrolysis of GGM Product Applications 7. Materials and Methods 7.1. Reactor Setup 7.2. Analysis 8. Results 9. Conclusions 10. Future work

3 Issue Key Introduction - Biorefineries SHORTAGE OF RAW MATERIALS IN THE LONG TERM SUSTAINABLE DEVELOPMENT Energy Sector Environmental implications Renewable resources Biomass Lignocellulosic biomass 15-25% 45-35% Cellulose Lignin Cellulose Hemicellulose Hemicellulose Hemicellulose: Lignin 25-35% mannans, xylans, arabinans, galactans and derivatives

4 Aim of the Project Continuous production of rare sugars via acid hydrolysis of different types of hemicelluloses Minimizing the formation of degradation products Furfural, HMF, formic acid, levulinic acid Developing a mathematical model of the process

5 H Y D R O L Y S I S Hydrolysis of hemicelluloses Hemicelluloses are heteropolysaccharides composed of different sugar units Hydrolysis: Process for production of rare sugars Rare sugars: highly value-added compounds in biorefinery Enzymatic Acid Homogeneous Heterogeneous Selective acid hydrolysis is more efficient than enzymatic Different methods: two-step method

6 Why continuous? TMP Hydrolysis Monomers Logical next step Norway spruce is one of the main wood species in the Nordic countries Very versatile raw material Advantages of continuous reactor Sugarbased polymers heat transfer capacities better concentration profiles size mixing rates operating flexibility

7 Galactoglucomannan (GGM) Softwood derived polysaccharide Extracted from TMP from Norway spruce (Picea abies) Structure: (1 4)-linked β-d-mannopyranosyl (1 4)-linked β-d-glucopyranosyl α-d-galactopyranosyl O-acetyl groups Galactose Glucose Mannose O-acetylgalactoglucomannan

8 Hydrolysis of GGM Protonation of the glycosidic bond Catalyst: Hydrochloric acid (HCl) H + Acid catalyst (H + ) H + GGM mannose glucose galactose

9 Product Applications

10 Product Applications - Production of pharmaceuticals - Decrease of the symptoms in lower urinary tract diseases - Growth accelerator for swine - Hydrogenation to mannitol: further applications - Applications in the pharmaceutical and alimentary industry - Nutrient medium for maintaining viability of neutral cells - Use in cytotoxic and anti-inflammatory drugs - Transformation to tagatose or fucose: further applications

11 Materials and Methods Continuous reactor Isothermal conditions Parameters to study Conversion Sugar concentration Reaction conditions ph = 0 2 T= ºC c GGM = 0.5%wt 6%wt Raw Material Catalyst GGM HCl

12 Reactor Setup Reactor Characteristics Glass Dimensions L ph = 1 m L r = 3 m d t = 3 mm Preheater Reactor

13 Pump Reactor Setup GGM HCl

14 Flowsheet Reactor Setup

15 Analysis Gas Chromatography Analysis (GC) Total organic carbohydrate content (Methanolysis) Monomeric sugar content Oligomer content (DP<6) Analysis: - Quantitative - Qualitative Mass balance Conversion Challenging and time consuming techniques

16 Results Residence time GGM HCl Total flow Flow rate 0,1 ml/min + 0,1 ml/min = 0,2 ml/min d t = 3mm Preheater L = 1m V = 7,07 ml t r = 71 min d t = 3mm Reactor L = 3m V = 19,56 ml t r =98 min Preheater Reactor Flow rate d t = 3mm L = 1m V = 7,07 ml d t = 3mm L = 3m V = 19,56 ml GGM HCl Total flow 0,075 ml/min + 0,1 ml/min = 0,175 ml/min t r = 71min t r =94 min t r =121min

17 κ [mv] Results Residence time Experimental Measurement 0,90 Pulse experiment V = 19,56 ml 0,80 0,70 0,60 0,50 0,40 0,30 0,20 0,10 0,00 0:00:00 0:28:48 0:57:36 1:26:24 1:55:12 2:24:00 2:52:48 3:21:36 Time [h:min:sec]

18 C [mg/ml] - Mannose is produced in larger amounts - Concentration in the outlet tend to be constant Results Monomer Production ph = 0,3 ; T = 90ºC 0,300 Initial concentration of GGM inside the reactor: C 0 =0,43 mg/ml 0,250 0,200 0,150 0,100 0,050 - Experimental Mannose ratio for sugar production: Galactose Glucose Gal:Glu:Man 1:1,5:5 Average Mannose Average Galactose Average Glucose 0, Residence time Time-on-stream [min]

19 C [mg/ml] Results Monomer Production ph = 0,24; T=90ºC 0,3 Initial concentration of GGM inside the reactor: C 0 =0,30 mg/ml 0,25 0,2 0,15 0,1 0,05 Mannose Galactose Glucose Average Mannose Average Galactose Average Glucose Residence time Time-on-stream [min] - Mannose is produced in larger amounts - Concentration in the outlet tend to be constant

20 C [mg/ml] Results Monomer Production ph = 0,3 ; T = 95ºC 0,25 Initial concentration of GGM inside the reactor: C 0 =0,32 mg/ml 0,2 0,15 0,1 0,05 Mannose Galactose Glucose Average mannose Average Glucose Average Galactose Residence time Time-on-stream [min] - Mannose is produced in larger amounts - Concentration in the outlet tend to be constant

21 Conversion [%] Results ph dependence ph = 0.3 ph = Residence time Time [min] Outlet conversion: Lower ph Higher conversion

22 Conversion [%] Results Temperature dependence T= 90ºC T = 95ºC Residence time Time [min] Outlet conversion: Higher temperature Higher conversion

23 Conclusions High production of sugars was accomplished < 90% conversion was reached No degradation products were detected ph Conversion T Conversion First time demonstration of feasibility of continuous operation mode

24 Future Work Hydrolysis of different hemicelluloses Arabinogalactan Glucuroxylan Inulin Use of different catalysts Organic acids Heterogeneous catalysts fixed bed reactor Optimization of reactor conditions in continuous mode Separation of product fractions by chromatographic techniques

25 Acknowledgements The work is a part of the activities of Process Chemistry Centre (PCC), a centre of excellence financed by Åbo Akademi University

26 Thanks for your attention!