TOWARDS SUSTAINABLE AND EFFICIENT BIOFUELS PRODUCTION USE OF PERVAPORATION IN PRODUCT RECOVERY AND SEPARATION

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1 1 TOWARDS SUSTAINABLE AND EFFICIENT BIOFUELS PRODUCTION USE OF PERVAPORATION IN PRODUCT RECOVERY AND SEPARATION POKE Summer School Saaremaa, Estonia D.Sc.(Tech.) Johanna Niemistö FACULTY OF TECHNOLOGY / Environmental Engineering August 2014

2 DOCTORAL THESIS -1 Public defence I. García V, Päkkilä J, Ojamo H, Muurinen E & Keiski RL (2011) Challenges in biobutanol production: How to improve the efficiency? Renewable and Sustainable Energy Reviews 15(2): II. Niemistö J, Saavalainen P, Isomäki R, Kolli T, Huuhtanen M & Keiski RL (2013) Biobutanol production from biomass. In: Gupta VK & Tuohy MG (eds) Biofuel Technologies: Recent developments. Berlin-Heidelberg, Springer-Verlag: III. Niemistö J, Saavalainen P, Pongrácz E & Keiski RL (2013) Biobutanol as a potential sustainable biofuel - Assessment of lignocellulosic and waste-based feedstock. Journal of Sustainable Development of Energy, Water and Environment Systems 1(2): IV. Niemistö J, Kujawski W & Keiski RL (2013) Pervaporation performance of composite poly(dimethyl siloxane) membrane for butanol recovery from model solutions. Journal of Membrane Science 434: V. Niemistö J, Pasanen A, Hirvelä K, Myllykoski L, Muurinen E & Keiski RL (2013) Pilot study of bioethanol dehydration with polyvinyl alcohol membranes. Journal of Membrane Science 447:

3 INTRODUCTION Production and use of biomass-based biofuels and chemicals have been increasing strongly during the 21st century 3 Bioethanol and biodiesel are currently the most used liquid transportation biofuels Alternative biofuels are also needed to fulfill the increasing demand in the future Biobutanol has superior fuel properties over ethanol Figure from Renewables 2013 Global status report (REN21 (2013), p. 30)

4 THE AIM OF THIS WORK 4 To gain new knowledge on the production of transportation biofuels (biobutanol and bioethanol) To point out the main challenges and bottlenecks in the present production processes To increase sustainability and process efficiency of production steps, e.g. by using enhanced processing techniques and improving the efficiency in energy and material usage To evaluate the feasibility of pervaporation as the product separation method for the recovery and purification of bioethanol and biobutanol, and other solvents after the fermentation step

5 THE CONTENT OF THESIS Biobutanol production process: Papers I and II Superior fuel properties of butanol as compared to ethanol Challenges in the processing Overview of the used processing techniques and recent improvements Biorefinery perspective and resource efficiency 5 Bioethanol dehydration by pervaporation: Paper V Feasibility study for the pervaporative bioethanol dehydration Pretreatment of bulk bioethanol by activated carbon filtration Towards sustainable and efficient biofuels production use of pervaporation in product recovery and purification Sustainability assessment of feedstocks for biobutanol production: Paper III European legislation and sustainability criteria Sustainability assessment of four feedstock sources Solvent recovery from aqueous solutions by pervaporation: Paper IV Permeation performance study for the removal of n-butanol, acetone and ethanol from aqueous model solutions

6 PRODUCTION OF TRANSPORTATION BIOFUELS (FERMENTATION PROCESS), PAPERS I AND II Feedstocks Lignocellulosics Agricultural residues Crop biomasses Municipal solid waste Non-food biomasses Industrial byproducts Sugar rich biomass Sugar beat Sugar cane Whey permeate Starch rich biomass Grains Potato Upstream processing Pretreatment methods Biological Chemical Physical Physico-chemical Hydrolysis Enzymatic Dilute acid Concentrated acid Detoxification Adsorption Enzymatic Evaporation Extraction Ion exchange resins Overliming Fermentation Batch Fed-Batch Continuous Extractive Flash Immobilized cells Simultaneously saccharification & fermentation (SSF) Two-stage Fermentation by using E.coli or other microorganisms Acetone-Butanol-Ethanol (ABE) -process Clostridium bacteria A:B:E ratio 3:6:1 Products Acetone Butanol Ethanol Acetic acid Butyric acid CO 2 H 2 Downstream processing Adsorption Distillation Gas stripping Liquid-liquid -extraction Perstraction Pervaporation Reverse osmosis 6

7 PROCESS INTENSIFICATION 7 Challenges Cost of substrates and unit processes final cost of a product depends usually strongly on the efficiencies of the separation and purification steps Product inhibition low product concentrations, low yield Complex process chain Solutions Novel processing techniques Hybrid processes Biorefineries: combined production of fuels, value-added chemicals, power, heat, etc.

8 SUSTAINABILITY OF BIOFUELS PRODUCTION Sustainability assessment in relation to biofuels production focuses mainly on land use and GHG emissions All sustainability aspects should be taken into account including environmental, economic and social impacts Selection of proper indicators and measurement tools for impact evaluation is challenging Harmonization and common criteria are needed Figure:

9 SUSTAINABILITY ASSESSMENT OF FEEDSTOCKS FOR BIOBUTANOL PRODUCTION, PAPER III 9 Indicators chosen for biobutanol feedstock evaluation: Economic impacts Environmental impacts Social impacts Feedstock price Biodiversity and land use change Customer acceptance and social dialog Processing costs Hazardous and toxic material usage Ethicality and competing demand of raw materials Value added Emissions (e.g. GHG) Employment effects Energy Wastes vs. by-products Water consumption Health and safety issues Innovation and education potential Crop biomass: corn Non-edible crop: straw Food by-product: whey Wood-based biomass: saw dust

10 PRINCIPLE OF PERVAPORATION 10 Feed side (liquid phase) μ f > μ p P f > P p Permeate side (gas phase) Feed Retentate Temperature Concentration ₒ ₒ ₒ ₒ ₒ ₒ ₒ ₒ Bulk feed Boundary layer membrane ₒ ₒ ₒ ₒ ₒ ₒ Porous support layer ₀ More permeable compound Less permeable compound 1 Sorption 2 Diffusion 3 Desorption Permeate Non-porous selective layer

11 PERVAPORATION 11 Advantages Disadvantages + No additional chemicals needed - Membrane swelling + More energy efficient than conventional distillation + Simple, compact, flexible and versatile + High selectivity also in lower operating conditions - Temperature and concentration polarization - Membrane fouling - More or less tailor-made membranes needed for different applications + Can be combined to hybrid systems - Industrial scale applications may be difficult to achieve Some potential applications: Removal of organic compounds from aqueous systems (separation of products/inhibitors/valuable compounds from fermentation broths) Dehydration of organic solvents (azeotropic mixtures) Case-specific selection of the best techniques for each process

12 PERVAPORATION EXPERIMENTS, PAPERS IV AND V 12 ABE-process Ethanol process Target compound Acetone, butanol and ethanol Water Membrane Hydrophobic PDMS-PAN Hydrophilic PVA Membrane area 170 cm 2 1 and 2 m 2 Feed solution Around 3 litres, solvent concentration below 5 wt% Temperature 42 C 98 C 35 and 70 kg, ethanol concentration ~ wt% Other remarks Different binary, ternary and quaternary model feed solutions used Activated carbon filtration was used as pretreatment before the pervaporation

13 PERVAPORATION EXPERIMENTS Sampling Analysis of samples (e.g. by gas chromatography) Determination of separation performance: Flux Selectivity Separation factor Pervaporation Separation Index (PSI) 13 1) Heating unit, 2) Feed tank, 3) Feed sampling, 4) Circulation pump, 5) Membrane unit, 6) Cold traps, 7) Vacuum pump

14 BUTANOL RECOVERY Membrane permselectivity followed the order of acetone n-butanol>ethanol Separation of ethanol was much lower as compared to acetone and n-butanol Permeation of n-butanol is preferable in solutions containing several organic compounds, indicating that the tested PDMS-membrane has a potential to be used in the ABE fermentation process. 14 Niemistö J., Kuawski W., Keiski R.L. (2013), Pervaporation performance of composite poly(dimethyl siloxane) membrane for butanol recovery from model solutions. Journal of Membrane Science, 434:55 64.

15 CONCLUSIONS 15 Demand of biofuels and biochemicals produced from renewable raw materials is increasing continuously Production processes should be technically feasible economic sustainable in economic, environmental and social matters Separation processes especially have an important role in chemical industry and in biorefineries Figure: Harvey B.G. & Meylemans H.A. (2011), J. Chem. Technol. Biotechnol. 86: 2 9 Results of this thesis show that pervaporation can be used as a separation method in biofuels production processes

16 ACKNOWLEDGEMENTS 16 The Academy of Finland The Finnish Funding Agency for Technology and Innovation (Tekes) St1 Biofuels Oy, Sulzer Chemtech Ltd. Doctoral Program in Energy Efficiency and Systems (EES) Graduate School in Chemical Engineering (GSCE) Oulun läänin talousseuran maataloussäätiö Tauno Tönning foundation Riitta and Jorma J. Takanen foundation Research group of Mass and Heat Transfer Processes Research group of Professor Kujawski (Nicolaus Copernicus University, Poland) Family and friends

17 17 THANK YOU! THANK YOU FOR YOUR ATTENTION!