Different Aspects of Biomass Pyrolysis: A General Review

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1 Different Aspects of Biomass Pyrolysis: A General Review Ersan Pütün Anadolu University, Department of Materials Science and Engineering, Eskisehir, Turkey eputun@anadolu.edu.t

2 Outline Energy needs and demands Biomass Biomass potential of the World and Turkey Thermochemical Conversions Pyrolysis Carbonaceous products obtained from pyrolysis and their characterization methods Bio-oil Bio-char A research example Environmental, Economical and Future Aspects of Biomass Pyrolysis

3 Energy? 3E Energy Economy Ecology Meeting the global energy challenge. Sufficient Available Secure Reliable Sustainable Fossil Fuels Biomass

4 Biomass The term biomass is ascribed to biological materials derived from living, or recently living organisms. The chemical composition of biomass is complex and very different from that of fossil fuels. Agricultural crops& residues Forestry crops& residues Industrial residues Animal residues Municipal solid waste Energy crops

5 Biomass Potential of the World Currently biomass provides approximately 13% of world primary energy supply and more than 75% of global renewable energy. Indeed it is estimated that bio-energy could contribute 25 33% of global energy supply by World production of biomass is estimated at 146 billion metric tons a year, mostly wild plant growth

6 Biomass Potential of Turkey Agricultural Biomass Potential of Turkey Total available waste amount= 16 MT (303,2 PJ total heating value) Foresty Biomass Potential of Turkey Total forestry waste= 48 MT (1,5 MTEP)

7 Lignocellulosic Material Cellulose (40-50 %) Glucose monomer Hemicellulose (25-35 %) Xylose monomer Lignin (16-33 %) Phenyl propanoid monomer units Water (3-10 %) Organic extractives Inorganics (K, Na, Ca, Mg, P etc.) Biomass can be considered as a natural composite material which is mainly consisted of cellulose, hemicellulose, and lignin. Minor amounts of minerals and lower molecular weight organic materials (solvent extractives) are also included in the biomass structure

8 Thermal Degradation of Cellulose Different thermal degradation reactions: T> 200 C water is lost T> 250 C several competing pyrolytic reactions grouped into three basic classifications: o At lower temperatures water, CO, CO 2 and a carbonaceous char o At higher temperatures depolymerization of the cellulose chain anhydroglucose derivatives, volatile organic materials and tars. o At still higher temperatures bond cleavage of cellulose low molecular weight compounds.

9 Thermal Degradation of Hemicellulose Hemicellulose decomposes C more volatiles, less tars, and less chars than cellulose. Hemicellulose is lost in slow pyrolysis of wood C, with most of this loss occurring above 180 C.

10 Thermal Degradation of Lignin Lignin decomposes C. Lignin pyrolysis more residual char DTA studies a broad exotherm plateau from 290 C to 389 C followed by a second exotherm, peaking at 420 C tailing out to beyond 500 C. Lignin decomposition in wood begins at 280 C continues to C with a maximum rate at C.

11 Thermochemical Conversions Biomass Thermochemical Process Combustion Gasification Pyrolysis Liquifaction/ Hydro thermal upgrading Intermediate Process Hot gases Low-energy gas Medium-energy gas Char Hydrocarbons Final Product Steam Process Heat Electricity Internal Combustion Engines Fuel gases Methane Syn Liquids Methanol Gasoline Fuel-oil and distillates Main processes, intermediate energy carriers and final energy products from the thermo-chemical conversion of biomass

12 Pyrolysis.the thermo-chemical decomposition of organic materials by heating in the absence of oxygen. It commonly refers to lower temperature thermal processes producing liquids as the primary product. C containing feedstock Gaseous products Pyrolysis Volatiles Liquid products C rich char

13 Factors Effecting Biomass Pyrolysis. Feedstock characteristics Particle size Biological constituent content (cellulose, hemicelloluse, lignin & extractives) Moisture content Ash content Mineral content Morphology Operating conditions Temperature Heating rate Pressure Catalyst presence Sweeping gas Vapor residence time Reactor type (Retorts, Kilns, Screw Reactors, Rotary drum reactors, Moving bed reactors, Microwave reactors, Fluidised bed reactors

14 Bio-char can be used as solid fuel in boilers can be used futher for the gasification process to obtain hydrogen rich gas by thermal cracking, could be used directly as activated carbons or for the production of activated carbon via applying different methods, useful as a sorbent for air pollution control as well as for wastewater treatment. serve as catalysts and catalyst supports

15 Bio-oil used as combustion fuel, used for power generation, can be used for production of chemicals and resins, can be used as a transportation fuel and could be a good substitute for fossil fuels, suitable blend with diesel oil may be used as diesel engine fuels, easily stored and transported, and hence need not to be used at the production site.

16 Chemical characterization of bio-oil Complete chemical characterization of bio-oil is difficult and many instrumental and analytical techniques are used for characterization: o GC, GC-MS volatile compounds o HPLC, HPLC-electrospray MS nonvolatile compounds o NMR nuclear magnetic resonance types of hydrogens or carbons in specific structural groups, bonds, area integrations o FT-IR Fourier transform infrared spectroscopy functional groups o GPS Gel Permentation Spectroscopy molecular weight distributions

17 Chemical characterization of char o Solid state NMR nuclear magnetic resonance types of carbons in specific structural groups o FT-IR Fourier transform infrared spectroscopy functional groups o SEM Scanning Electronic Microscopy surface morphology o EDX Energy-dispersive X-ray Spectroscopy surface chemicals o XRD X-Ray Diffraction crystallographic structure o Gas adsorption Surface area determination

18 Pathway of our studies Pyrolysis Carbon Materials Oil shale & Coal Plastics Biomass Carbonaseous Material Decomposition Liquid Solid Activated Carbon Activated Carbon Adsorption Chemical Activation Physical Activation Carbon Foam Heavy Metals Toxic Dyes Phenolic Compounds Pesticides Petroleum Hydrocarbons C-Fiber Gas GC TG-FTIR TG-MS

19 A research example carried on pyrolysis. Project Title; Investigation of pyrolysis kinetics of coal,biomass and plastic blends by thermogravimetry and characterization of the products (Supported by Anadolu University Scientific Research Council, Project No: 1001F68) Purpose; Identification of pyrolytic and co-pyrolytic behaviours of different biomass samples with coal and plastics

20 Raw materials and their selection Waste PET bottles Lignite Biomass Samples Polyethylene terephthalate (PET) is one of the most commonly used polymers. In million tons and 1.6 million tons of PET were collected in worldwide and Europe, respectively. Turkey has approximately 2% of the world's lignite reserves. However, Turkish lignites have low calorific value and contain relatively higher amounts of ash and sulphur. Corn stalk and cotton stalk were agricultural wastes. Hazelnut shells were industrial wastes of food processing. Enormous production of hazelnut, cotton and corn in Turkey leads to availibility of bio-wastes. Hazelnut production 1 st country Cotton production 8 th country Corn production 21 st country throughout the world

21 Experimental Procedure RAW MATERIALS Air dried, ground, screen analysis, proximate, ultimate and compositional analysis Preperation of blends (with a ratio of 1/1 wt./wt.) In fixed bed reactor PYROLYSIS In combined TGA/FT-IR/MS system Bio-oil Bio-Char CHARACTERIZATION Kinetic Studies Elemental Analysis FT-IR 1 H-NMR GC-MS Elemental Analysis FT-IR BET surface area SEM-EDX Evolved Gas Analysis (EGA)

22 Results (Product Yields) Heating rate= 10 o C/min Pyrolysis temperature= 550 o C Nitrogen flow rate= 100 cm 3 /min Higher tar yield Highest char yield

23 Results (Product Yields, cont d) Heating rate= 10 o C/min Pyrolysis temperature= 550 o C Nitrogen flow rate= 100 cm 3 /min PET caused synergetic effect on co-pyrolysis of biomass by increasing liquid product yields. Lignite addition of biomass decreased liquid product yield and increased char yield due to high ash content.

24 Results (Elementel Analysis & Heating Values) Raw materials wt. % Cotton stalk Corn stalk Hazelnut shells PET Lignite C 40,28 35,95 48,36 61,34 56,25 H 5,95 5,42 6,22 4,28 4,96 N 1,46 1,49 0,50 0,00 1,58 S 0,29 0,12 0,00 0,00 0,37 O 52,02 57,02 44,92 34,38 36,84 H/C 1,760 1,796 1,533 0,831 1,051 O/C 0,967 1,191 0,697 0,421 0,492 High heating value (HHV) (MJ/kg) 12,856 9,709 17,233 20,726 19,576 Highest C content Highest HHV

25 Results (Elementel Analysis & Heating Values) Cotton stalk Corn stalk Hazelnu t shells Lignite Cotton s. Liquid products +PET Corn s. +PET Hazelnuts. +PET Cotton s. + Lignite Corn s. +Lignite Hazelnut s. + Lignite PET +Lignite C 67,47 66,44 68,04 75,33 59,33 65,84 84,12 68,98 65,57 70,56 60,22 H 7,80 7,39 7,15 7,92 5,29 5,70 7,49 7,59 7,41 6,98 4,53 N 1,32 0,78 0,90 0,46 0,02 0,44 0,26 0,65 0,84 1,01 0,38 S O ** 23,41 25,39 23,91 16,29 35,36 28,02 8,13 22,78 26,18 21,45 34,87 H/C 1,38 1,33 1,25 1,25 1,06 1,03 1,06 1,31 1,35 1,18 0,90 O/C 0,26 0,29 0,26 0,16 0,45 0,32 0,07 0,25 0,30 0,23 0,44 HHV (MJ/kg) 29,86 28,56 29,02 33,97 21,33 25,45 37,80 30,18 28,15 30,07 20,62 Highest C content Highest HHV

26 Results (Elementel Analysis & Heating Values) Cotton stalk Corn stalk Hazelnut shells Chars Lignite Cotton s. +PET Corn s. +PET Hazelnuts. +PET C 63,74 57,55 85,43 67,92 67,20 71,20 86,54 H 1,22 1,21 1,61 1,53 1,38 1,48 1,59 N 0,46 0,91 0,014 1,40 0,36 0,81 0,05 S 0,31 0,00 0,00 0,39 0,28 0,00 0,00 O 34,27 40,33 12,946 28,76 30,78 26,51 11,82 H/C 0,228 0,251 0,225 0,268 0,245 0,248 0,219 O/C 0,404 0,526 0,114 0,318 0,344 0,280 0,103 HHV(MJ/kg) 17,171 13,941 28,889 20,034 19,20 21,441 29,439 Highest C content Highest HHV

27 Results (BET Surface Areas of Chars) Sample BET Surface Area(m 2 /g) Hazelnut shell 10,37 Corn stalk 102,60 Cotton stalk 0,97 Lignite 10,57 Hazelnut Shell +PET 143,28 Hazelnut shell+lignite 117,37 Corn stalk +PET 294,91 Corn stalk + Lignite 78,36 Cotton stalk +PET 20,29 Cotton stalk + Lignite 43,14 PET-Lignite 61,34 In co-pyrolysis, cotton stalk and lignin presence decreased BET surface area values. On the other hand, co-pyrolysis wit PET increased BET surface areas.

28 Results (FT-IR and SEM-EDX Analysis of Chars) Pyrolysis caused evolvemet of oxygen from the structure of raw materials and cracking of the aromatic structures which leads to carbonaceous solid products. Morphologies of bio-chars were observed different when PET and lignite were blended with biomass samples. BET surface area of corn stalk+pet char were foung highest and SEM micrographs showed formation of porous structure due to pyrolysis SEM micrograph and EDX analysis of Corn stalk + PET sample

29 Results As a general conclusion of the project, valuable solid and liquid products can be achieved from co-pyrolysis of biomass with lignite or PET under proper conditions. By this way, disposal of plastics and evaluation of low-ranked coals by copyrolysis may be a sustainable and an enironmentally-friendly choice.

30 Environmental, Economical and Future Aspects of Biomass Pyrolysis Biomass pyrolysis technology offers a great deal of potential for human and environmental gain No net CO 2 or SO x addition to the atmosphere Unfortunately, combustion of bio-oil also has its drawbacks. ohigh particulate content

31 Environmental, Economical and Future Aspects of Biomass Pyrolysis (cont d) In the short term, carbonaceous products from biomass cannot hope to compete with the vast fossil fuel. Studies have emerged, however, of smaller niche markets available for biomass pyrolysis technology. In the long term, larger scale biorefineries which would integrate every step of processing and refinement will take place and these bio-refineries will be more economical than today s smaller markets. To reinforce the utilization of biomass conversion technologies the states should reduce the taxes and support manufacturers for production.

32 Environmental, Economical and Future Aspects of Biomass Pyrolysis (cont d) Biomass provides a promising answer to world energy needs and a potentially viable alternative to fossil fuels. The utilization of a significant amount of these biomass resources would also require a concerted R&D effort for developing technologies to overcome the cost barriers. Demonstration projects and incentives (e.g., tax credits, price supports, and subsidies) would be required. Additional efforts would be required to discern the potential impact that large-scale forest and crop residue collection and production of perennial crops could have on traditional markets for agricultural and forest products.

33 Environmental, Economical and Future Aspects of Biomass Pyrolysis (cont d) Unique among biomass-generated fuels in its variability and limitless feedstock possibilities, bio-oil is the most versatile alternative fuel on the market. In order for bio-oil to gain a larger share of this market, a few important issues need to be addressed. o Scale-up from smaller models used now o Reduce overhead costs o Set industry-wide product quality standards o Encourage developers and investors o Disseminate information to the public o Address environmental and safety issues in handling and storage

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