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CONVERSION OF BIOMASS TO BIOFUELS WSU ChE 481/581 & UI BAE 504 LECTURER: MANUEL GARCIA-PEREZ, Ph.D. Department of Biological Systems Engineering 205 L.J.

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Presentation on theme: "CONVERSION OF BIOMASS TO BIOFUELS WSU ChE 481/581 & UI BAE 504 LECTURER: MANUEL GARCIA-PEREZ, Ph.D. Department of Biological Systems Engineering 205 L.J."— Presentation transcript:

1 CONVERSION OF BIOMASS TO BIOFUELS WSU ChE 481/581 & UI BAE 504 LECTURER: MANUEL GARCIA-PEREZ, Ph.D. Department of Biological Systems Engineering 205 L.J. Smith Hall, Phone number: MEEETING PLACE: EME B46, TUESDAY AND THURSDAY 1:25-2:40 AM CREDIT HOURS: 3 THERMOCHEMICAL CONVERSION SECTION

2 OUTLINE OF OUR PREVIOUS LECTURE A.- GASIFICATION B.- COMBUSTION C.- HYDROTHERMAL CONVERSION

3 LECTURE 1 INTRODUCTION TO BIOMASS THERMOCHEMICAL CONVERSION TECHNOLOGIES AND THERMO-CHEMICAL REACTIONS LECTURE 2 TORREFACTION AND PYROLYSIS (SLOW AND FAST) LECTURE 3 GASIFICATION, COMBUSTION AND HYDROTHERMAL CONVERSION LECTURE 4 CHARACTERIZATION AND USES OF PRODUCTS OF THERMOCHEMICAL REACTIONS (THERMOCHEMICAL BIO-REFINERIES) OVERVIEW OF THE THERMOCHEMICAL SECTION

4 FOURTH LECTURE OUTLINE CHARACTERIZATION AND USES OF PRODUCTS OF THERMOCHEMICAL REACTIONS (THERMOCHEMICAL BIO-REFINERIES): A.- BIO-OIL C.- SYNTHESIS GAS B.- BIO-CHAR

5 A.- BIO-OIL PYROLYSIS OIL IS A DARK-BROWN, FREE FLOWING LIQUID FUEL DERIVED FROM PLANT MATERIAL VIA FAST PYROLYSIS. PYROLYSIS OIL CAN BE STORED, PUMPED AND TRANSPORTED LIKE PETROLEUM PRODUCTS AND CAN BE COMBUSTED DIRECTLY IN BOILERS, GAS TURBINES, AND SLOW TO MEDIUM SPEED DIESEL FOR HEAT AND POWER. IT HAS A DENSITY OF 1.2 kg/L, AND HEATING VALUE GJ/t (APPROXIMATELY 55 % OF THE HEATING VALUE OF DIESEL ON A VOLUMETRIC BASIS AND 45 % ON A WEIGHT BASIS). PYROLYSIS OIL IS NOT DANGEROUS BUT IT IS ACIDIC. pH IS 2-3 COMPARED WITH DIESEL AT pH 5. IT IS NOT AN HOMOGENEOUS LIQUID. IF LEFT STANDING FOR LONG PERIODS, LIGNIN WILL EVENTUALLY PRECIPITATE. THE ACIDIC AND CORROSIVE NATURE OF PYROLYSIS OIL MEANS THAT ENHANCEMENTS ARE REQUIERED FOR STORAGE AND TRANSPORTATION, BUT THESE ARE NOT ONEROUS. STORAGE VESSELS AND PIPING SHOULD BE STAINLESS 304, PVC, TEFLON OR LIKE SUBSTANCES. Bradley D: European Market Study for Bio-oil (Pyrolysis Oil) Climate Change Solutions. National Team Leader – IEA Bioenergy Task 40-Biotrade. BLADES BEFORE COMBUSTIONBLADES AFTER COMBUSTION ORENDA TURBINE Brown R, Holmgren J: Fast Pyrolysis and Bio-Oil Upgrading. JenniferHolmgren presentationslides.pdfhttp://www.ars.usda.gov/sp2UserFiles/Program/307/biomasstoDiesel/

6 DIRECT USE AS A FUEL A.- BIO-OIL THE CRUDE BIO-OIL CAN BE USED FOR THE GENERATION OF HEAT AND ELECTRICAL POWER. THE COMBUSTION OF PYROLYSIS OILS IN INTERMEDIATE SIZE BOILERS (100 kW to 1 MW) SEEMS TO BE ECONOMICALLY VIABLE. SEVERAL RESEARCH PROGRAMS HAVE BEEN UNDERTAKEN TO ADAPT MORE EFFICIENT SYSTEMS (TURBINES, STATIONARY DIESELS, BOILERS) TO BE ABLE TO OPERATE WITH BIO-OILS AS FUEL. Meier D, Faix O: State of the art of applied fast pyrolysis of lignocellulosic materials- a review. Bioresource Technology 68 (1999) THE HEATING VALUE OF BIO-OILS (ABOUT 17 MJ/kg WET WEIGHT BASIS OR 22 MJ/kg DRY WEIGHT BASIS) IS TYPICALLY ABOUT HALF OF THAT OF N o 2 FUEL OIL. IT DOES NOT BURN EFFICIENTLY WITHOUT PRE-HEATING AND TEND TO GEL AFTER SITTING FOR PROLONGED PERIODS OF TIME. BECAUSE OF THESE PROPERTIES BIO-OIL DOES NOT CURRENTLY APPEAR TO BE A GOOD SUBSTITUTE FOR No 2 FUEL IN HOME HEATING APPLICATIONS. BIO-OILS CAN BE USED IN INDUSTRIAL BOILERS BUT REQUIRES THE BOILER BE EQUIPPED WITH STAINLESS STEEL OR PLASTIC-LINED, FUEL INJECTION COMPONENTS AND STORAGE TANKS TO RESIST CORROSION, A SYSTEM THAT HEATS AND/OR STIRS THE BIO-OIL DURING STORAGE PREVENTING GELLING, AND A SYSTEM THAT PRE- HEATS THE INCOMING BIO-OIL TO A TEMPERATURE HIGH ENOUGH TO ENSURE A GOOD ATOMIZATION. Laid DA, Brown RC, Amonette JE, Lehmann J: Review of the Pyrolysis Platform for coproducing bio-oil and bio-char. Bio-fuels, Bioproducts & Biorefining. 2009,

7 BIO-OIL COMPOSITION CELLULOSE WATER H 2 O 5-HYDROXYMETHYL FURFURAL HEMICELLULOSE LIGNIN METHANOL CH 3 OH GLYOXAL H-C-C-H OO FORMALDEHYDE H-C-H O FORMIC ACID H-C-OH O HYDROXYACETALDEHYDE DIMER HO O O OH ACETOL CH 3 -C-CH 2 OH O ACETIC ACID H 3 C-C-OH O CYCLOPENTANONE O FURANS 2-FURALDEHYDE O O O OH FURFURYL ALCOHOL PHENOL OH CRESOL CH 3 VANILLIN OH OCH 3 O H METHANOL CH 3 OH OH OCH 3 O H H 3 CO VANILLIN HO OCH 3 CH 3 EUGENOL LEVOGLUCOSAN OH O O CELLOBIOSE OH O O O SUGARS XYLOSEARABINOSE OH HO O OH ETHYLENE GLYCOL HOCH 2 CH 2 OH H O O H HO A.- BIO-OIL

8 PRODUCTS OF LIGNIN A.- BIO-OIL Bayerbach R, Meier D: Characterization of the water-insoluble fraction from fast Pyrolysis liquids (pyrolytic lignin) Part IV: Structure elucidation of oligomeric molecules. Journal of Analytical and Applied Pyrolysis, 85 (2009) MAIN MONOMERS OBTAINED FROM THE PYROLYSIS OF LIGNIN DIMERIC STRUCTURE IN PYROLYTIC LIGNIN BOILING POINT ( o C) (Yield: 4-5 mass %) WATER INSOLUBLE-CH 2 Cl 2 SOLUBLE COMPOUNDS (Yield: mass %)

9 A.- BIO-OIL Bayerbach R, Meier D: Characterization of the water-insoluble fraction from fast Pyrolysis liquids (pyrolytic lignin) Part IV: Structure elucidation of oligomeric molecules. Journal of Analytical and Applied Pyrolysis, 85 (2009) STRUCTURAL PROPOSAL OF PYROLYSIS LIGNIN FOR (A) TETRAMETERS (B) PENTAMERS (C) HEXAMERS (D) HEPTAMERS (E) OCTAMERS A B BD E WATER -CH 2 Cl 2 INSOLUBLE COMPOUNDS (YIELD AROUND 2 mass %)

10 A.- BIO-OIL Meier D, Faix O: State of the art of applied fast pyrolysis of lignocellulosic materials- a review. Bioresource Technology 68 (1999) Laid DA, Brown RC, Amonette JE, Lehmann J: Review of the Pyrolysis Platform for coproducing bio-oil and bio-char. Bio-fuels, Bioproducts & Biorefining. 2009, BIO-OIL PRODUCED BY FAST PYROLYSIS OF CELLULOSIC BIOMASS IS AN EMULSION OF WATER (APPROXIMATELY 20 mass %) AND A WIDE RANGE OF ORGANIC COMPOUNDS INCLUDING ORGANIC ACIDS, ALDEHYDES, ALCOHOLS, PHENOLS, CARBOHYDRATES AND LIGNIN DERIVED OLIGOMERS. Bayerbach R, Meier D: Characterization of the water-insoluble fraction from fast Pyrolysis liquids (pyrolytic lignin) Part IV: Structure elucidation of oligomeric molecules. Journal of Analytical and Applied Pyrolysis, 85 (2009) Brown R, Rover M, Li M, Kuzhiyi N, Johnston L, Jones S: What does it mean to characterize bio-oil? TC Biomass Conference, Chicago, IL, September 16-18, 2008

11 A B C D E F A.- BIO-OIL MONO-PHENOLS AND FURANS WATER + ACETIC ACID + ACETOL FORMIC ACID+ HAA SUGARS LIGNIN OLIGOMERS OLIGOSUGARS GC/MS GC/FID

12 Crude Bio-oils Family A,B Ethanol Hydroxyacetaldehyde Acetic acid Formic acid Acetaldehyde Methyl glyoxal Glyoxal Acetol Propionic acid Acetone Methyl formate Methanol Family C Phenol Furfuryl alcohol Catechol Hydroquinone Bernzenediol Syringaldehyde 3-ethylphenol Levoglucosan Cellobiosan 1,6-anhydroglucofuranose Fructose Family D, F Family E Oligomers HYDROLYSIS AND FERMENTATION (ETHANOL) -C=O NH 3 SLOW RELEASE FERTILIZER -COOH NOXOLENE TM (NOx Reduction) Lime BIOLIME TM (NOx/SOx Reduction) Phenolics ADHESIVES, SUFACTANTS ADVANCED CARBONS WOOD PRESERVATIVES RESINS SUFACTANTS Steam All functional groups SYNTHESIS GAS, HYDROGEN Carbonyl groups Carboxyl groups Extractive derived comp. APPLICATIONS USING THE WHOLE BIO-OILS APPLICATIONS USING FRACTIONS SPECIAL CHEMICALS DE- ICERS RESINS ANTI-OXIDANTS CO-POLYESTERS, CO-POLYAMIDES SUFACTANTS SOLVENTS FUELS HOW TO SEPARATE BIO-OIL FRACTIONS? A.- BIO-OIL

13 USES A.- BIO-OIL THE ISOLATION OF CHEMICALS AND PRODUCING SPECIAL PRODUCTS BASED ON PYROLYSIS OILS IS AN ACTIVE AREA OF RESEARCH. SEVERAL PRODUCTS FROM BIO-OILS HAVE BEEN DEVELOPED: LIQUID SMOKE, PHENOL FORMALDEHYDE RESINS, PHENOLICS, LEVOGLUCOSAN, LEVOGLUCOSANONE, OCTANE ENHANCER, SLOW RELEASE FERTILIZER, NO X /SO X REDUCERS (BIOLIME TM ). PYROLYTIC ACETIC ACID MEETS BETTER THE NEEDS OF ELECTRONIC CHIPS PRODUCTION. CREOSOTE, A FRACTION OF WOOD TAR, IS TRADITIONALLY USED IN THE PHARMACEUTICAL INDUSTRY, AND WATER FREE WOOD TARS IN VETERINARY MEDICINE. Meier D, Faix O: State of the art of applied fast pyrolysis of lignocellulosic materials- a review. Bioresource Technology 68 (1999) Laid DA, Brown RC, Amonette JE, Lehmann J: Review of the Pyrolysis Platform for coproducing bio-oil and bio-char. Bio-fuels, Bioproducts & Biorefining. 2009, BIO-OIL CAN BE UP-GRADED INTO SYNTHETIC TRANSPORTATION FUELS. ONE APPROACH WOULD GASIFY BIO-OIL AND CONVERT SYNGAS TO SYNTHETIC GASOLINE AND DIESEL THROUGH FISCHER-TROPSCH (F-T) CATALYTIC SYNTHESIS. THE EUROPEAN UNION (EU) IS CONSIDERING THE DEVELOPMENT OF A DISTRIBUTED NETWORK OF BIOMASS PYROLYZERS THAT WOULD SUPPLY BIO-OIL TO A CENTRALIZED F-T REFINERY. THE HIGH INITIAL INVESTMENT REQUIRED TO BUILD A F-T REFINERY IS THE BIGGEST OBSTACLE TO THE ADOPTION OF THIS APPROACH IN THE US. FURTHERMORE F-T REFINERIES HAVE LOW CARBON-CONVERSION EFFICIENCIES (ABOUT 50 %).

14 A.- BIO-OIL BIO-OIL REFINERIES (BIO-OIL FERMENTATION) Brown R, Holmgren J: Fast Pyrolysis and Bio-Oil Upgrading. JenniferHolmgren presentationslides.pdfhttp://www.ars.usda.gov/sp2UserFiles/Program/307/biomasstoDiesel/ TO PRODUCE GASOLINE AND DIESEL

15 A.- BIO-OIL ANOTHER APPROACH WOULD HYDROCRACK BIO-OIL TO TRANSPORTATION FUELS IN A MANNER SIMILAR TO THE REFINING OF PETROLEUM TO GASOLINE. BIO-OIL VAPORS WILL BE RECOVERED AS A CARBOHYDRATE-DERIVED AQUEOUS PHASE AND A LIGNIN RICH FRACTION. THE AQUEOUS PHASE WOULD BE STEAM REFORMED TO HYDROGEN. THE LIGNIN FRACTION WOULD BE HYDROCRACKED TO HYDROCARBONS. THE LARGE VOLUME OF HYDROGEN REQUIRED FOR THIS PROCESS WOULD COME FROM THE STEAM REFORMER. THIS PROCESS IS ATTRACTIVE AND COULD EMPLOY THE INFRASTRUCTURE AT EXISTING PETROLEUM REFINERIES. Laid DA, Brown RC, Amonette JE, Lehmann J: Review of the Pyrolysis Platform for coproducing bio-oil and bio-char. Bio-fuels, Bioproducts & Biorefining. 2009, BIO-OIL REFINERIES (GREEN GASOLINE FROM THE LIGNIN DERIVATIVES AND HYDROGEN FROM THE WATER SOLUBLE PHASE ) FIBROUS BIOMASS PYROLYZER CYCLONE BIO-OIL RECOVERY STEAM REFORMING Char Bio-oil vapor Hydrogen HYDROCRACKER Carbohydrate derived aqueous phase Lignin Green Diesel

16 A.- BIO-OIL REACTIVITY SCALE OF OXYGENATED GROUPS UNDER HYDROTREATMENT CONDITIONS Elliott DC: Historical developments in Hydroprocessing Bio-oils. Energy & Fuels 2007, 21,

17 A.- BIO-OIL HYDROTREATMENT OF WHOLE PYROLYSIS OILS HYDROTREATING IS ONE OF THE KEY PROCESSES TO MEET QUALITY SPECIFICATIONS FOR REFINERY FUEL PRODUCTS. HIGH PRESSURE IS USED TO ADD HYDROGEN AND PRODUCE PREMIUM DISTILLATE PRODUCTS Mass % Pyrolysis Oil100 H2H2 Feed Products 4-5 Lt ends 15 Gasoline30 Diesel Water, CO Brown R, Holmgren J: Fast Pyrolysis and Bio-Oil Upgrading. presentationslides.pdfhttp://www.ars.usda.gov/sp2UserFiles/Program/307/biomasstoDiesel/ 38

18 Jones SB, Holladay JE, Valkenburg C, Stevens DJ, Walton C, Kinchin C, Elliott DC, Czernik S: Production of Gasoline and Diesel from Biomass via Fast Pyrolysis. Hydrotreating and Hydrocracking. A Design Case. Pacific Northwest National Laboratory. US DOE. Contact DE-ACO5-76 RL)1830. PNNL BLOCK DIAGRAM (PYROLYSIS PLANT COUPLESD WITH A BIO-OIL REFINERY) (OVER 2000 TONS/DAY) BLOCK DIAGRAM (PYROLYSIS PLANT NOT COUPLED WITH A BIO-OIL REFINERY) STABLE OILSUNSTABLE OILS REFINERIES A.- BIO-OIL

19 FLOW DIAGRAM FOR PYROLYSIS OIL STABILIZATION (BIO-OIL REFINERIES) Jones SB, Holladay JE, Valkenburg C, Stevens DJ, Walton C, Kinchin C, Elliott DC, Czernik S: Production of Gasoline and Diesel from Biomass via Fast Pyrolysis, Hydrotreating and Hydrocracking: A Design Case. US Department of Energy, February 2009, PNNL Rev. 1. DE-AC05-76RL01830 PYROLYSIS OIL HYDROGEN FUEL GAS TO REFORMER UP-GRADED BIO-OIL TO DEBUTANIZER WASTE WATER 2000 T/DAY OF HYBRID POPLAR UNIT TO PRODUCE 76 MILLION GALLONS/YEAR OF GASOLINE AND DIESEL (115 gal/t) Cost of production: 1.74 $/gal gasoline/diesel A.- BIO-OIL

20 Jones SB, Holladay JE, Valkenburg C, Stevens DJ, Walton C, Kinchin C, Elliott DC, Czernik S: Production of Gasoline and Diesel from Biomass via Fast Pyrolysis. Hydrotreating and Hydrocracking. A Design Case. Pacific Northwest National Laboratory. US DOE. Contact DE-ACO5-76 RL)1830. PNNL HYDROCRACKING AND PRODUCT SEPARATION REFINERIES A.- BIO-OIL UP-GRADED BIO-OIL FUEL GAS TO REFORMERS NAPHTHA DIESEL

21 USES B.- BIO-CHAR BIOCHAR IS A COMBUSTIBLE SOLID (18 MJ/kg) THAT CAN BE BURNED TO GENERATE ENERGY IN MOST SYSTEMS THAT ARE CURRENTLY BURNING COAL. THE SUFUR CONTENT OF BIO-CHAR IS LOW AND HENCE INDUSTRIAL COMBUSTION OF BIO-CHAR GENERALLY DOES NOT REQUIRE TECHNOLOGY FOR REMOVING SO x FROM EMISSIONS TO MEET EPA EMISSION LIMITS. EMISSIONS OF NO X FROM COMBUSTION OF BIOCHAR ARE COMPARABLE TO THAT COMING FROM COAL COMBUSTION AND REQUIRE ABATEMENT TECHNOLOGY. THE ASH CONTENT OF BIO-CHAR DEPENDS SUBSTANTIALLY ON THE FEESTOCK. SOME BIOMASSES SUCH AS CORN STOVER AND RICE HUSK CONTAIN HIGH LEVELS OF Si, AND AFTER PYROLYSIS IT IS CONCENTRATED IN THE ASH. COMBUSTION OF HIGH Si BIO-CHAR WILL CAUSE SCALING IN THE WALL OF THE COMBUSTION CHAMBER AND DECREASE THE USABLE LIFE OF THESE CHAMBERS. LOW-ASH BIO-CHARS CAN BE USE IN METALLURGY AND AS A FEEDTOCK FOR PRODUCTION OF ACTIVATED CARBON, WHICH HAS MANY USES, SUCH AS AN ADSORBENT TO REMOVE ODORANTS FROM AIR STREAMS AND BOTH ORGANIC AND INORGANIC CONTAMINANTS FROM WASTE WATER STREAMS. Laid DA, Brown RC, Amonette JE, Lehmann J: Review of the Pyrolysis Platform for coproducing bio-oil and bio-char. Bio-fuels, Bioproducts & Biorefining. 2009,

22 USES B.- BIO-CHAR AN EMERGIN NEW USE OF BIO-CHAR IS AS A SOIL AMENDMENT. THE HARVESTING OF CROP RESIDUES FOR THE PRODUCTION OF BIOENERGY COULD HAVE ADVERSE IMPACTS ON SOIL AND ENVRIONMENTAL QUALITY. THE HARVESTING OF RESIDUES REMOVES SUBSTANTIAL AMOUNT OF PLANT NUTRIENTS FROM SOIL AGRO- ECOSYSTEMS. UNLESS THESE NUTRIENTS ARE REPLACED BY ADDITION OF SYNTHETIC FERTILIZERS, MANURE OR OTHER SOIL AMENDMENTS, THE PRODUCTIVITY OF THE SOIL WILL DECLINE. EVEN IF SYNTHETIC FERTILIZERS ARE ADDED TO MAINTAIN SOIL FERTILITY, THE SUSTAINED REMOVAL OF CROP RESIDUES WITHOUT COMPENSATING ORGANIC AMENDMENTS WILL CAUSE A DECLINE IN LEVELS OF SOIL ORGANIC MATTER, A DECLINE IN THE CATION EXCHANGE CAPACITY, A DECLINE IN WATER HOLDING CAPACITY AND ACCELERATED ACIDIFICATION OF SOILS. THE RETURN OF THE BIO-CHAR CO-PRODUCT OF PYROLYSIS TO THE SOIL FROM WHICH THE BIOMASS WAS HARVESTED HAS ALSO BEEN PROPOSED AS A MEANS TO ENHANCE SOIL QUALITY AND THEREBY THE SUSTAINABILITY OF BIOENERGY PRODUCTION SYSTEMS. FURTHERMORE, MANY OF THE NUTRIENTS IN BIOMASS ARE RECOVERED WITH THE CHAR PRODUCT OFFERING OPPORTUNITIES FOR NUTRIENT RECYCLING. Laid DA, Brown RC, Amonette JE, Lehmann J: Review of the Pyrolysis Platform for coproducing bio-oil and bio-char. Bio-fuels, Bioproducts & Biorefining. 2009,

23 THE HISTORY OF TERRA PRETA (DARK EARTH) B.- BIO-CHAR FRANCISCO DE ORELLANA WAS THE FIRST EUROPEAN TO EXPLORE THE CENTRAL AMAZON IN THE YEAR HE REPORTED BACK TO THE SPANISH COURT THAT A LARGE AGRICULTURAL CIVILIZATION EXISTED ALONG THE BANKS OF THE AMAZON. FOR CENTURIES, MOST PEOPLE ASSUMED THAT DE ORELLANA HAS INVENTED THE STORIES OF A CIVILIZATION IN AMAZONIA. BUT DURING THE TWENTIETH CENTURY, ANTHROPOLOGISTS FOUND EVIDENCE OF EXTENSIVE REGIONS OF TERRA PRETA SOILS WITH POT SHARDS AND OTHER ARTIFACTS ASSOCIATED WITH A LARGE CIVILIZATION. THESE SOILS HAVE HIGH CONTENTS OF BIO-CHAR EXHIBIT VERY HIGH FERTILITY COMPARED WITH THE INFERTILE OXISOLS OF THE REGION. Laid DA, Brown RC, Amonette JE, Lehmann J: Review of the Pyrolysis Platform for coproducing bio-oil and bio-char. Bio-fuels, Bioproducts & Biorefining. 2009, REPRESENTATIVE TERRA PRETA AND OXISOLS PROFILES. TERRA PRETA SOILS TYPICALLY HAVE HIGHER LEVELS OF ORGANIC MATTER, HIGHER MOISTURE-HOLDING CAPACITY, AND HIGHER LEVELS OF BIOAVAILABLE N, P, Ca AND K THAN THE OXISOLS FROM WHICH THEY ARE DERIVED.

24 B.- BIO-CHAR THE APPLICATION OF BIO-CHAR TO SOIL IS PROPOSED AS A NOVEL APPROACH TO ESTABLISH A SIGNIFICANT, LONG-TERM SINK FOR ATMOSPHERIC CARBON DIOXIDE IN TERRESTRIAL ECOSYSTEMS. APART FROM POSITIVE EFFECTS IN BOTH REDUCING EMISSIONS AND INCREASING THE SEQUESTRATION OF GREENHOUSE GASES. CONVERSION OF BIOMASS C TO BIO-CHAR C (SLOW PYROLYSIS) LEADS TO SEQUESTRATION OF ABOUT 50 % OF THE INITIAL C COMPARED TO THE LOW AMOUNTS RETAINED AFTER BURNING (3%) AND BIOLOGICAL DECOMPOSITION (< % AFTER YEARS), THEREFORE YIELDING MORE STABLE SOIL C THAN BURNING OR DIRECT LAND APPLICATION OF BIOMASS. SOME ANALYSES REVELEAD THAT UP TO 12 % OF THE TOTAL ANTHROPOGENIC C EMISSIONS BY LAND USE CHANGE CAN BE OFF SET ANNUALLY IN SOIL, IF SLASH-AND CHAR IS REPLACED BY SLASH AND CHAR SYSTEMS. Lehmann J, Gaunt J, Rondon M: Bio-char sequestration in terrestrial ecosystems – a review. Mitigation and Adaptation Strategies for Global Change (2006) 11: RANGE OF BIOMASS CARBON REMAINING AFTER DECOMPOSITION OF CROP RESIDUES. BIOCHAR CAN RESULT IN A NET REMOVAL OF CARBON FROM THE ATMOSPHERE, ESPECIALLY WITH ENHANCED NET PRIMARY PRODUCTIVITY

25 B.- BIO-CHAR PRODUCTION OF ACTIVATED CARBON Ioannidou O, Zabaniotou A: Agricultural residues as precursors for activated carbon production – A review. Renewable and Sustainable Energy Reviews 11 (2007) PHYSICAL ACTIVATION: IT IS A TWO CONSECUTIVE STEP PROCESS. IT INVOLVES CARBONIZATION OF A CARBONACEOUS MATERIAL FOLLOWED BY THE ACTIVATION OF THE RESULTING CHAR AT ELEVATED TEMPERATURES IN THE PRESENCE OF A SUITABLE OXIDIZING AGENT SUCH AS CARBON DIOXIDE, STEAM, AIR OR THEIR MIXTURES. THE ACTIVATION GAS IS USUALLY CO 2, SINCE IT IS CLEAN, EASY TO HANDLE AND IT FACILITATES CONTROL OF THE ACTIVATION PROCESS DUE TO THE SLOW REACTION RATE AT TEMPERATURES AROUND 800 o C. CARBONIZATION TEMPERATURE RANGE BETWEEN 400 AND 850 oC, THE ACTIVATION TEMPERATURE RANGE BETWEEN 600 AND 900 o C. CHEMICAL ACTIVATION: THE TWO STEPS ARE CARRIED OUT SIMULTANEOUSLY, WITH THE PRECURSOR BEING MIXED WITH CHEMICAL ACTIVATING AGENTS, AS DEHYDRATING AGENTS AND OXIDANTS. CHEMICAL ACTIVATION OFFERS SEVERAL ADVANTAGES SINCE IT IS CARRIED OUT IN A SINGLE STEP, COMBINING CARBONIZATION AND ACTIVATION, PERFORMED AT LOWER TEMPERATURES AND THEREFORE RESULTING IN THE DEVELOPMENT OF A BETTER POROUS STRUCTURE, ALTHOUGH THE ENVIRONMENTAL CONCERNS OF USING CHEMICAL AGENTS FOR ACTIVATION COULD BE DEVELOPED. BESIDE PART OF THE ADDITIVES USED (ZINC SALTS, PHOSPHORIC ACID) CAN BE EASILY RECOVERED. THE MOST COMMON CHEMICAL AGENTS USED ARE: ZnCl 2, KOH, H 3 PO 4 AND K 2 CO 3. TEMPERATURES (BETWEEN 300 AND 850 o C) STEAM-PYROLYSIS: THE RAW BIOMASS IS EITHER HEATED AT MODERATE TEMPERATURE ( o C) UNDER A FLOW OF PURE STEAM, OR HEATED AT o C UNDER A FLOW OF JUST STEAM.

26 B.- BIO-CHAR Ioannidou O, Zabaniotou A: Agricultural residues as precursors for activated carbon production – A review. Renewable and Sustainable Energy Reviews 11 (2007) PROPERTIES OF ACTIVATED CARBON SURFACE AREA: THE BET SURFACE AREA OF CHAR IS IMPORTANT, BECAUSE, LIKE OTHER PHYSICO-CHEMICAL CHARACTERISTICS, IT MAY STRONGLY AFFECT THE REACTIVITY AND COMBUSTION BEHAVIOUR OF THE CHAR. THE INCREASE IN THE SURFACE AREA IS DUE TO THE OPENING OF THE RESTRICTED PORES. SIZE OF PORES: BOTH SIZE AND DISTRIBUTION OF MICROPORES, MESOPORES AND MACROPORES DETERMINE THE ADSORPTIVE PROPERTIES OF ACTIVATED CARBONS. FOR EXAMPLE SMALL PORE SIZE WILL NOT TRAP LARGE ADSORBATE MOLECULES, AND LARGE PORES MAY NOT BE ABLE TO RETAIN SMALL ADSORBATES. MATERIALS WITH HIGH CONTENT OF LIGNIN DEVELOP ACTIVATED CARBONS WITH MACROPOROUS STRUCTURE, WHILE RAW MATERIALS WITH HIGHER CONTENT OF CELLULOSE YIELD ACTIVATED CARBON WITH A PREDOMINANTLY MICROPOROUS STRUCTURE. ACIDIC SURFACES ARE IN GENERAL FAVOURABLE FOR BASIC GAS ADSORPTION SUCH AS AMMONIA WHILE ACTIVATED CARBONES WITH BASIC SURFACE CHEMICAL PROPERTIES ARE SUITABLE FOR ACID GAS ADSORPTION SUCH AS SULPHUR DIOXIDE. ACTIVATED CARBON CAN ALSO BE USED TO REMOVE POLLUTANTS FROM LIQUID PHASE. MOST OF THE RELEVANT BEEN THE WASTE WATER TREATMENT, THE DRINKING WATER, THE INDUSTRIAL EFFLUENTS PURIFICATION AND GROUND WATER TREATMENT. ACTIVATED CARBONS ARE USED FOR THE REMOVAL OF PHENOLS, PHENOLIC COMPOUNDS, HEAVY METALS AND DYES, METAL IONS AND MERCURY (II). PHENOLIC COMPOUNDS EVEN IN LOW CONCENTRATIONS CAN BE AN OBSTACULE TO USE AND RE-USE WATER. PHENOLS CAUSE UNPLEASANT TASTE AND ODOUR OF DRINKING WATER AND EXERT NEGATICE EFFECTS ON DIFFERENT BIOLOGICAL SYSTEMS. THEY ALSO ADSORB ARSENIC OR CAN BE USED AS A SUPPORT CATALYST FOR LIQUID PHASE REACTIONS.

27 PRODUCTION AND COMPOSITION C.- SYNTHESIS GAS: Introduction IN PRINCIPLE SYNGAS (PRIMARILY CONSISTING OF CO AND H 2 ) CAN BE PRODUCED FROM ANY HYDROCARBON FEEDSTOCK INCLUDING: NATURAL GAS, NAPHTHA, RESIDUAL OIL, PETROLEUM COKE, COAL AND BIOMASS. THE CONVERSION OF SYNGAS INTO LIQUID FUELS AMOUNT FOR MORE THAN HALF THE CAPITAL COST OF THESE PLANTS. THE CHOICE OF TECHNOLOGY FOR SYNGAS PRODUCTION ALSO DEPENDS ON THE SCALE OF THE SYNTHESIS GAS OPERATION. SYNGAS PRODUCTION FROM SOLID FUELS IS MORE EXPENSIVE THAN FROM NATURAL GAS BECAUSE IT REQUIRES HIGHER CAPITAL INVESTMENTS WITH THE ADDITION OF FEEDSTOCK HANDLING AND MORE COMPLEX SYNGAS PURIFIATION OPERATIONS. Spath PL, Dayton DC: Preliminary Screening-Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas. NREL/tp IN ITS SIMPLEST FORM, SYNGAS IS COMPOSED OF TWO DIATIOMIC MOLECULES CO AND H 2 THAT PROVIDE THE BUILDING BLOCKS UPON WHICH AN ENTIRE FIELD OF FUEL SCIENCE AND TECHNOLOGY IS BASED. THIS MIXTURE HAD MANY NAMES DEPENDING ON HOW IT WAS FORMED AND USED: PRODUCER GAS, TOWN GAS, BLUE WATER GAS, SYNTHESIS GAS AND SYNGAS. THE BEGINNING OF THE 20 th CENTURY SAW THE DAWN OF FUELS AND CHEMICALS SYNTHESIS FROM SYNGAS.

28 Steam Reforming Or Partial Oxidation Natural GasNaphtha CoalBiomass CO 2 + H 2 CO + H 2 (Syngas) Ammonia Synthesis Hydrotreating Hydrogenation Fuel Cell Power FT Synthesis of Liquid Fuels Methanol Synthesis Catalytic processes based on H 2 or syngas are among the most basic and critically important processes in providing food, fuel, and chemical resources C.- SYNTHESIS GAS: Introduction

29 Spath PL, Dayton DC: Preliminary Screening-Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas. NREL/tp SYNTHESIS GAS CONVERSION PROCESSES C.- SYNTHESIS GAS: Introduction

30 The first ammonia synthesis plant was started-up in 1913 by BASF with a total production capacity of 30 tons per day. Synthetic ammonia production grew from 10,000 tons per year in 1913 to about 120 million tons per year in Large-scale ammonia synthesis has made it feasible for the worlds industrial- agriculture complex to feed a population of several billion people Ammonia Synthesis The first large-scale synthesis of methanol in 1923 from syngas marked the beginning of the modern chemical industry. Conversion to formaldehyde is currently one of the largest chemical applications of methanol and accounts for usage of about 60% of the methanol produce. Methanol Synthesis Fischer-Tropsch Synthesis (FTS), the production of liquid hydrocarbons from syngas, was developed by Fischer and Tropsch in the mid-1920s. It played an important role in supplying the fuel needs of Germany during World War II when its petroleum supplies were cut off and has been the main source of fuels and chemical for South Africa since the 1950s. It is a developing option for environmentally-sound production of chemicals and liquid fuels from biomass, coal, and natural gas. Fischer-Tropsch Synthesis C.- SYNTHESIS GAS: Introduction

31 Steam Reforming (SR): C n H m + nH 2 O = nCO + (n + 1/2m)H 2 CH 4 + H 2 O = CO + 3H 2 CO 2 Reforming (Dry Reforming): CH 4 + CO 2 = 2CO + 2H 2 Partial Oxidation (POX): CH 4 + ½ O 2 = CO + 2H 2 Autothermal Reforming (ATR) CH 4 + H 2 O = CO + 3H 2 n* (CH 4 + ½ O 2 = CO + 2H 2 ) H o =200 kJ/mol H o =247 kJ/mol H o =-40 kJ/mol Thermally Neutral Process Is Possible * Gasification is a process where one oxidizes the solid with either O 2 or H 2 O (ex. Coal Gasification) C.- SYNTHESIS GAS: Production

32 SR POX ATR H 2 /CO Ratio Natural Gas Naphtha THE SYNGAS COMPOSITION, MOST IMPORTANTLY THE H 2 /CO RATIO, VARIES AS A FUNCTION OF PRODUCTION AND FEEDSTOCK. STEAM METHANE REFORMING YIELDS H2/CO RATIOS OF 3/1 WHILE COAL GASIFICATION YIELDS RATIOS CLOSER TO UNITY OR LOWER. C.- SYNTHESIS GAS: Production

33 THE DOMINANT TECHNOLOGY FOR HYDROGEN PRODUCTION IS STEAM METHANE REFORMING. IF THE FEEDSTOCK IS METHANE THEN 50 % OF THE HYDROGEN COME FROM THE STEAM. THE REFORMIG REACTION IS HIGHLY ENDOTHERMIC AND IS FAVORED BY HIGH TEMPERATURES AND LOW PRESSURES. THE SHIFT REACTION IS EXOTHERMIC AND IS FAVORED AT LOW TEMPERATURES. IN INDUSTRIAL REFORMERS, THE REFORMING AND SHIFT REACTUONS RESULT IN A PRODUCT COMPOSITION THAT CLOSELY APPROACHES EQUILIBRIUM. THE REFORMER STEAM TO CARBON RATIO IS USUALLY BETWEEN 2-6 DEPENDING ON THE PROCESS CONDITIONS. EXCESS STEAM IS USED TO PREVENT COKING IN THE REFORMER TUBES. CONVENTIONAL STEAM REFORMING CATALYSTS ARE mass % NiO ON A SUPPORT (ALIMINA, CEMENT OR MAGNESIA). Spath PL, Dayton DC: Preliminary Screening-Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas. NREL/tp C.- SYNTHESIS GAS: Production H 2 S + ZnO ZnS + H 2 O CO + H 2 O CO 2 + H 2

34 THE DOMINANT TECHNOLOGY FOR HYDROGEN PRODUCTION IS STEAM METHANE REFORMING. IF THE FEEDSTOCK IS METHANE THEN 50 % OF THE HYDROGEN COME FROM THE STEAM. THE REFORMIG REACTION IS HIGHLY ENDOTHERMIC AND IS FAVORED BY HIGH TEMPERATURES AND LOW PRESSURES. THE SHIFT REACTION IS EXOTHERMIC AND IS FAVORED AT LOW TEMPERATURES. IN INDUSTRIAL REFORMERS, THE REFORMING AND SHIFT REACTUONS RESULT IN A PRODUCT COMPOSITION THAT CLOSELY APPROACHES EQUILIBRIUM. THE REFORMER STEAM TO CARBON RATIO IS USUALLY BETWEEN 2-6 DEPENDING ON THE PROCESS CONDITIONS. EXCESS STEAM IS USED TO PREVENT COKING IN THE REFORMER TUBES. CONVENTIONAL STEAM REFORMING CATALYSTS ARE mass % NiO ON A SUPPORT (ALIMINA, CEMENT OR MAGNESIA). Spath PL, Dayton DC: Preliminary Screening-Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas. NREL/tp C.- SYNTHESIS GAS: Production LIGHT OXYGENATED COMPOUNDS

35 3C 2 H 6 + 4H 2 O 2CH 4 + 4CO + 9H 2 C C H H H H H H Ethane Steam Reforming Reaction Mechanism The first step involves a rapid dehydrogenation of ethane to C 2 H 5 C.- SYNTHESIS GAS: Production

36 C 2 H 5 OH + 3H 2 O 2CO 2 +6H 2 C C H H OH H H H CC H H H H CC H HOH H dehydrogenation -H 2 dehydration -H 2 O acetaldehyde coke CH 4 + CO decomposition steam reforming +3H 2 O 5H 2 + 2CO 2 Ethanol Steam Reforming (ESR) ??? Surface intermediates C.- SYNTHESIS GAS: Production

37 ALTHOUGH STEAM REFORMING HAS BEEN AROUND FOR MANY YEARS, MORE STUDIES ON THE REFORMING OF OXIGENATED HYDROCARBONS IS NEEDED. C.- SYNTHESIS GAS: Production

38 C.- SYNTHESIS GAS: Production of Ammonia 3H 2 + N 2 2NH 3 H (500 o C) = -109 kJ/mol N 2 AMMONIA IS MANUFACTURED FROM NITROGEN FIXED FROM THE ATMOSPHERE AND HYDROGEN. THE PROCESS WAS DEVELOPED IN THE EARLY 1900s BY FRITZ HABER AND CARL BOSCH USING A PROMOTDED IRON CATALYST. Catalyst: K promoted Fe P = 125 bar

39 C.- SYNTHESIS GAS: Production of Ammonia 3H 2 + N 2 2NH 3 H (500 o C) = -109 kJ/mol N 2 Ammonia Synthesis Loop For a Large Capacity (1000 ton per day) (H 2 :N 2 = :1)

40 C.- SYNTHESIS GAS: Production of Ammonia 3H 2 + N 2 2NH 3 H (500 o C) = -109 kJ/mol N 2

41 C.- SYNTHESIS GAS: Production of Ammonia 3H 2 + N 2 2NH 3 H (500 o C) = -109 kJ/mol N 2 At 400 o C

42 METHANOL SYNTHESIS BEGAN IN THE 1800s WITH THE ISOLATION OF WOOD ALCOHOL FROM THE DRY DISTILLATION (PYROLYSIS) OF WOOD. RESEARCH AND DEVELOPMENT EFFORTS AT THE BIGINNING OF THE 20 tH CENTURY INVOLVING THE CONVERSION OF SYNGAS TO LIQUID FUELS AND CHEMICALS LED TO THE DISCOVERY OF A METHANOL SYNTHESIS PROCESS CURRENTLY WITH DEVELOPMENT OF THE FISCHER- TROPSCH SYNTHESIS. IN FACT METHANOL IS A BYPRODUCT OF FISCHER-TROPSCH SYNTHESIS WHEN ALKALI METAL PROMOTED CATALYSTS ARE USED. METHANOL SYNTHSIS IS NOW WELL-DEVELOPED WITH HIGH ACTIVITY AND VERY HIGH SELECTIVITY. FOR ECONOMIX REASONS, METHANOL IS ALMOST EXCLUSIVELY PRODUCED VIA REFORMING OF NATURAL GAS (90 % OF THE WORLDWIDE METHANOL). HOWEVER A VARIETY OF FEEDSTOCKS OTHER THAN NATURAL GAS CAN BE USED TO PRODUCE ETHANOL. CURRENT INTEREST IN METHANOL IS DUE TO ITS POTENTIAL AS FUEL AND ITS USED AS CHEMICAL. IN PARTICULAR, METHANOL CAN BE USED DIRECTLY OR BLENDED WITH OTHER PETROLEUM PRODUCTS AS A CLEAN BURNING TRANSPORTATION FUEL. METHANOL IS ALSO AN IMPORTANT CHEMICAL INTERMEDIATE USED TO PRODUCE: FORMALDEHYDE, DIMETHYL ETHER (DME), METHYL TER-BUTYL ETHER (MTBE), ACETIC ACID, OLEFINS, METHYL AMINES, AND METHYL HALIDES. Spath PL, Dayton DC: Preliminary Screening-Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas. NREL/tp C.- SYNTHESIS GAS: Production of Methanol

43 C.- SYNTHESIS GAS CATALYTIC METHANOL SYNTHESIS FROM SYNGAS IS A CLASSICAL HIGH-TEMPERATURE, HIGH- PRESSURE EXOTHERMIC EQUILIBRIUM LIMITED SYNTHESIS REACTION. THE CHEMISTRY OF THIS REACTION IS AS FOLLOWS: CHEMISTRY CATALYSTS FOR METHANOL SYNTHESIS, A STOICHIOMETRIC RATIO, DEFINED AS (H 2 -CO 2 )/(CO+CO 2 ) OF SLIGHTLY ABOUT 2 IS PREFERRED. THIS MEANS THAT THERE WILL BE JUST THE STOICHIOMETRIC AMOUNT OF HYDROGEN NEEDED FOR METHANOL SYNTHESIS. THE FEED GAS COMPOSITION FOR METANOL SYNTHESIS IS TYPICALLY ADJUSTED TO CONTAIN 4-8 % CO 2 FOR MAXIMUM ACTIVITY AND SELECTIVITY. THE FIRST HIGH-TEMPERATURE, HIGH PRESSURE METHANOL SYNTHESIS CATALYSTS WERE ZnO/Cr 2 O 3 AND WERE OPERATED AT 350 o C and bar. IN 1966 ICI INTRODUCED A NEW, MORE ACTIVE Cu/ZnO/Al 2 O 3 CATALYST THAT BEGAN A NEW GENERATION OF METHANOL PRODUCTION BY USING LOW TEMPERATURES ( o C), LOW PRESSURE ( bar). Spath PL, Dayton DC: Preliminary Screening-Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas. NREL/tp PRODUCTION OF METHANOL

44 C.- SYNTHESIS GAS: Production of Methanol CO + H 2 O H 2 + CO 2 H (25 o C) = kJ/mol CO CO 2 + 3H 2 CH 3 OH + H 2 O H (25 o C) = kJ/mol CO 2 CO + 2H 2 CH 3 OH H (25 o C) = kJ/mol CO H (327 O C) = kJ/mol CO Operated with Cu/ZnO/Al 2 O 3 at 220~327 o C and 50~100atm

45 C.- SYNTHESIS GAS: Production of Methanol CO + H 2 O H 2 + CO 2 H (25 o C) = kJ/mol CO CO 2 + 3H 2 CH 3 OH + H 2 O H (25 o C) = kJ/mol CO 2 CO + 2H 2 CH 3 OH H (25 o C) = kJ/mol CO H (327 O C) = kJ/mol CO Operated with Cu/ZnO/Al 2 O 3 at 220~327 o C and 50~100atm Increasing in Equilibrium Conversion

46 C.- SYNTHESIS GAS: Production of Methanol CO + H 2 O H 2 + CO 2 H (25 o C) = kJ/mol CO CO 2 + 3H 2 CH 3 OH + H 2 O H (25 o C) = kJ/mol CO 2 CO + 2H 2 CH 3 OH H (25 o C) = kJ/mol CO H (327 O C) = kJ/mol CO Operated with Cu/ZnO/Al 2 O 3 at 220~327 o C and 50~100atm Increasing in Equilibrium Conversion

47 ONCE THE NATURAL GAS IS REFORMED THE RESULTING SYNTHESIS GAS IS FED TO A REACTOR VESSEL IN THE PRESENCE OF CATALYST TO PRODUCE METHANOL AND WATER VAPOR. THIS CRUDE METHANOL WHICH USUALLY CONTAINS UP TO 18 % WATER, PLUS ETHANOL, HIGHER ALCOHOLS, KETONES AND ETHERS IS FED TO A DISTILLATION PLANT THAT CONSISTS OF A UNIT THAT REMOVES THE VOLATILES AND A UNIT THAT REMOVES THE WATER AND HIGHER ALCOHOLS. THE UNREACTED SYNGAS IS RECIRCULATED BACK TO THE METHANOL CONVERTED RESULTING IN AN OVERALL CONVERSION EFFICIENCY OF 99 %. Spath PL, Dayton DC: Preliminary Screening-Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas. NREL/tp C.- SYNTHESIS GAS: Production of Methanol

48 ONE OF THE CHALLENGES ASSOCIATED WITH COMMERCIAL METHANOL IS REMOVING THE LARGE EXCESS HEAT OF REACTION. METHANOL SYNTHESIS CATALYST ACTIVITY INCREASES AT HIGH TEMPERATURES BUT SO DOES THE CHANGE FOR COMPETING SIDE REACTIONS. CATALYTIC LIFETIMES ARE ALSO REDUCED BY CONTINUOUS HIGH TEMPERATURE OPERATION AND TYPICALLY PROCESS TEMPERATURES ARE MAINTAINED BELOW 300 o C TO MINIMIZE CATALYST SINTERING. OVERCOMING THE THERMODYNAMIC CONSTRAINS IS ANOTHER CHALLENGE IN COMMERCIAL METHANOL SYNTHESIS. THE MAXIMUM PER-PASS CONVERSION EFFICIENCY OF SYNGAS TO METHANOL IS LIMITED TO ABOUT 25 %. HIGHER EFFICIENCIES PER-PASS CAN BE REALIZED AT LOW TEMPERATURE WHERE THE METHANOL EQUILIBRIUM IS SHIFTED TOWARDS PRODUCTS, HOWEVER, CATALYST ACTIVITIES GENERALLY DECREASE AS THE TEMPERATURE IS LOWERED. Spath PL, Dayton DC: Preliminary Screening-Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas. NREL/tp C.- SYNTHESIS GAS: Production of Methanol

49

50 C.- SYNTHESIS GAS: Fischer-Tropsch Synthesis History Period 1: Discovery ( ). FTS had its genesis in the early 1900s with the discovery by Sabatier and Senderens in 1902 that CO could be hydrogenated over Co, Fe, and Ni to methane. In 1925, Fischer and Tropsch first reported synthesis of hydrocarbon liquids and solid paraffins on Co-Fe catalysts under mild conditions of o C and 1 atm. Period 2: Commercial Development of the Fischer Cobalt-Based Process ( ). Fischer and Koch developed the precipitated Co/ThO 2 /kieselguhr catalyst between 1928 and 1934 which was to be the industrial standard for the next 12 years. They also found that the yields of different boiling point fractions were significantly affected by the operating temperature and pressure. In 1944, FTS provided 10-15% of Germanys synthetic fuel production with a total capacity of 5.4 Mbbl/yr. Period 3: The Age of Iron and Sasol ( ). Following WWII, American and British Allies followed up their intense interest in the German synfuels industry by sending teams of scientists to Germany. The U.S. team was referred to as the Technical Oil Mission (TOM). Due to a perceived shortage of

51 C.- SYNTHESIS GAS: Fischer-Tropsch Synthesis History (Continues) petroleum, the U.S., Great Britain, and Germany continued to support the FTS R&D. This R&D led to the development of inexpensive Fe catalysts. The first commercial GTL-FT plant (7,000 bbl/day) was operated in Brownsville, Texas, in 1951 by a Texaco-led consortium using fluidized bed reactor with Fe catalysts. However, this plant was shut down in 1957 after high gas prices and low cost petroleum from the Middle East made operation uneconomical. This fluidized bed reactor concept with Fe catalysts were used to build the Sasol Plant in South Africa in 1955 for the large-scale commercial FTS. It continues to operate and to produce 140,000 bbl/yr of synthetic fuels. Period 4: Rediscovery of FTS and Cobalt ( ). The 1973 oil embargo stimulated considerable support in the U.S. and Europe for R&D of synfuels technologies. During its heyday (1980) of FT research, significant progress was realized in relating catalyst properties to activity and selectivity. These new insights and innovations led to the development at Sasol, Gulf, Shell, and Exxon of substantially more economical FTS of diesel processes. Period 5: Birth/Growth of the GTL Industry Based on Biomass (1990-Present).

52 CHEMISTRY FTS HAS LONG BEEN RECOGNIZED AS A POLYMERIZATION REACTION WITH THE BASIC STEPS OF: 1.- REACTANT (CO) ADSORPTION ON THE CATALYST SURFACE 2.- CHAIN INITIATION BY CO DISSOCIATION FOLLOWED BY HYDROGENATION 4.- CHAIN TERMINATION 5.- PRODUCT DESORPTION FROM THE CATALYST SURFACE C.- SYNTHESIS GAS: Fischer-Tropsch Synthesis 3.- CHAIN GROWTH BY INSERTION OF ADDITIONAL CO MOLECULES FOLLOWED BY HYDROGENATION HH H CH 2 CH 3 CH 2 n (CH 2 ) n CH 3 (CH 2 ) n H H + - CH 3 -(CH 2 ) n -CH 3 CH 3 -(CH 2 ) (n-1) -HC=CH 2

53 C.- SYNTHESIS GAS: Fischer-Tropsch Synthesis FTS produces a broad spectrum of mainly alkanes and alkenes having carbon number from C1 to C50, the distribution of which is qualitatively governed by the Anderson-Schulz-Flory (ASF) kinetics: W n /n = (n-1) (1- ) 2 = r p / (r p +r t ) W n is the weight of product containing n carbon atoms and is the chain growth propagation probability The maximum obtainable weight percentage of light LPG hydrocarbons (C2-C4) is 56%, of gasoline (C5-C11) 47% and of diesel fuel (C12-C17) 40% The value of increases with decreasing H 2 /CO ratio, decreasing reaction temperature, and increasing pressure

54 C.- SYNTHESIS GAS: Fischer-Tropsch Synthesis

55 TYPES OF FISCHER-TROPSCH SYNTHESIS REACTOR Spath PL, Dayton DC: Preliminary Screening-Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas. NREL/tp REACTORS ONE OF THE CHALLENGES WITH FTS, IS THE REMOVAL OF THE LARGE AMOUNT OF EXCESS HEAT GENERATED BY THE EXOTHERMIC SYNTHESIS REACTIONS. INSUFFICIENT HEAT REMOVAL LEADS TO LOCALIZED OVERHEATING WHICH RESULTS IN HIGH CARBON DEPOSITION LEADING TO CATALYST DEACTIVATION. METHANE FORMATION ALSO DOMINATES AT HIGHER TEMPERATURES AT THE EXPENSE OF DESIRED FTS PRODUCTS. FOR LARGE-SCALE COMMERCIAL FTS REACTORS HEAT REMOVAL AND TEMPERATURE CONTROL ARE THE MOST IMPORTANT DESIGN FEATURES TO OBTAIN OPTIMUM PRODUCT SELECTIVITY AND LONG CATALYST LIFETIMES. OVER THE YIELDS BASICALLY FOUR FTS REACTOR DESIGNS HAVE BEEN USED COMMERCIALLY. C.- SYNTHESIS GAS: Fischer-Tropsch Synthesis


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