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11/09/2008 1 Gasification of waste biomass for the combined production of energy and adsorbents 1 International Workshop on Defining Issues in Biofuels R&D August 3-7, 2008 Cetraro (Calabria), Italy Dr. Guillermo San Miguel Senior Research Fellow Departamento Ingeniería Química y Medio Ambiente, Universidad Politécnica de Madrid C/ José Gutiérrez Abascal, 2, 28006 Madrid. [email protected] 2 INDEX 1. CONVENTIONAL BIOMASS GASIFICATION. 1.1 Introduction to biomass gasification. 1.2 Biomass feedstock for gasification. 1.3 Types of reactors for biomass gasification. 1.4 Biomass gasification today. 1.4 Biomass gasification today. 1.5 Gas cleaning and conditioning. 1.6 Conclusions with conventional biomass gasification. 2. BIOMASS GASIFICATION FOR THE PRODUCTION OF ADSORBENTS. 2.1 Introduction to activated carbons. 2.2 Feedstock for AC production. 2.3 Development of porosity during gasification. 3. GASIFICATION FOR THE COMBINED PRODUCTION OF ENERGY AND ADSORBENTS: CONSIDERATIONS AND PROPOSED TECHNOLOGY ADSORBENTS: CONSIDERATIONS AND PROPOSED TECHNOLOGY . 3.1 Previous research projects. 3.2 Considerations for dual purpose. 3.3 Project objectives. 4. CONCLUSIONS
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Page 1: San Miguel Presentation Calabria Small Size

11/09/2008

1

Gasification of waste biomass for the combined production of energy and adsorbents

1

International Workshop on Defining Issues in Biofuels R&D August 3-7, 2008Cetraro (Calabria), Italy

Dr. Guillermo San Miguel

Senior Research FellowDepartamento Ingeniería Química y Medio Ambiente,

Universidad Politécnica de MadridC/ José Gutiérrez Abascal, 2, 28006 Madrid.

[email protected]

2

INDEX

1. CONVENTIONAL BIOMASS GASIFICATION.1.1 Introduction to biomass gasification.1.2 Biomass feedstock for gasification.1.3 Types of reactors for biomass gasification.1.4 Biomass gasification today.1.4 Biomass gasification today.1.5 Gas cleaning and conditioning. 1.6 Conclusions with conventional biomass gasification.

2. BIOMASS GASIFICATION FOR THE PRODUCTION OF ADSORBENTS.2.1 Introduction to activated carbons.2.2 Feedstock for AC production.2.3 Development of porosity during gasification.

3. GASIFICATION FOR THE COMBINED PRODUCTION OF ENERGY AND ADSORBENTS: CONSIDERATIONS AND PROPOSED TECHNOLOGYADSORBENTS: CONSIDERATIONS AND PROPOSED TECHNOLOGY.

3.1 Previous research projects.3.2 Considerations for dual purpose.3.3 Project objectives.

4. CONCLUSIONS

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1. CONVENTIONAL BIOMASS GASIFICATION.

3

Wood gasification plant at Güssing (Austria) Laboratory scale gasifier.

1.1 INTRODUCTION TO BIOMASS GASIFICATION.

4

BIOMASS

Thermochemical processes

GasificationCombustion Pyrolysis Alcoholic Fermentation

Biochemical processes

Direct extraction

Anaerobic digestion

Steam, heat, electricity

Steam, heat.

Ethanol MethaneHot gases Syngas

Heat, electricity. Chemical synthesis,

H2

Char, GasesPyro-oil

Heat, electricity

Liquid fuels

CO

NVE

RSI

ON

PR

OC

ESS

ENER

GY

PRO

DU

CTS

USE

Transport Transport

THERMOCHEMICAL PROCESSES:

• Incineration: in excess of oxygen energy. Mature technology.• Pyrolysis: under inert conditions char, oils and gases. Experimental stage.• Gasification: under mildly oxidizing conditions syngas. Becoming commercial.

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PROCESS SCHEME OF BIOMASS GASIFICATION

Reception and conditioning

Gasification Gas cleaning and conditioning

Gas utilization

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- Drying.- Milling.

Particle size selection

- Drying.- Pyrolysis/carbonisation.- Partial combustion

H2 COCH4 N2

VOC Tars

- Condensation.- Separation of particulates.- Reforming of VOC

HEAT

ENERGY

CHEMICAL SYNTHESIS

- Particle size selection.- Pelletisation.

- Partial combustion. - Gasification.- Partial reforming and WGS.

- Reforming of VOC.- Cracking of tars.- WGS.- PSA.

HEAT and ENERGY- Boilers. - Internal combustion engines. -Gas turbines.

CHEMICAL SYNTHESIS- Methanol: MTBE and gasoline additives.- Fischer Tropsch: liquid fuels- H2 for fuel cells.

CHEMICAL REACTIONS IN GASIFICATION

Biomass combustion with oxygen:C + O2 ↔ CO2 ∆Hº = - 393,8 kJ/mol (complete combustion) (1)C + ½O2 ↔ CO ∆Hº = - 123,1 kJ/mol (incomplete combustion) (2)

Biomass gasification with steam or CO2:

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C + H2O ↔ CO + H2 ∆Hº = 118,5 kJ/mol (water gas reaction) (3)C + CO2 ↔ 2CO ∆Hº = 159,9 kJ/mol (Boudouard reaction) (4)

Steam reforming of small hydrocarbonsCH4 + H2O → CO + 3 H2 ∆Hº = 159,9 kJ/mol (5)

Methanation reactions: C + 2H2 ↔ CH4 ∆Hº = 210,5 kJ/mol (methanation reaction) (6)CO + 3H2 ↔ CH4 + H2O (CO methanation reaction) (7)

Water gas shift reaction:CO + H2O ↔ CO2 + H2 ∆Hº = - 41,2 kJ/mol (water gas shift reaction) (8)

Oxidation of syngas components:Oxidation of syngas components:CO + ½O2 ↔ CO2 ∆Hº = - 238,9 kJ/mol (9)H2 + ½O2 ↔ H2O ∆Hº = - 285,9 kJ/mol (10)

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1.2 BIOMASS FEEDSTOCK FOR GASIFICATION

- Plentiful and cheap.- High carbon content.- Low humidity content.- Low ash content.

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a b

• Biomass crops: wood chips from pine, eucalyptus, poplar (a).

• Agricultural and forest waste: pruning, clearing, straw.

• Industrial waste: oil, sugar, wine, paper, beer production.

Nut shells and stones: almonds, olive stones (b).

Legume and grain hulls: rice (c)

c

Legume and grain hulls: rice (c).

Cereal and sugar cane bagass (d), straw (e). d e

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1.3 TYPES OF REACTORS FOR BIOMASS GASIFICATION.

FIXED BED REACTORS:

PIRÓLISIS

COMBUSTIÓN

REDUCCIÓN

CENIZAS

Gas, alquitranes. agua

Aire

PIRÓLISIS

COMBUSTIÓN

REDUCCIÓN

CENIZAS

Gas, alquitranes. agua

Aire

PIRÓLISIS

COMBUSTIÓN

REDUCCIÓN

CENIZAS

Gas, alquitranes. agua

Aire

PIRÓLISIS

COMBUSTIÓN

REDUCCIÓN

CENIZAS

Gas, alquitranes. agua

Aire

(1) downdraft (2) updraft (3) double fired (4) two-stage

• Status: mature and commercial. • Reactor configurations: updraft, downdraft, double fire, multi stage. • Capacity: small to medium (10-1000 KW). Big market for developed and developing economies.• Problem with tar removal (mainly updraft, only heat applications). • Higher investment costs per unit power: 4-8 Mill €/Mwel.• Higher electricity production costs: > 200 €/MWh.

• Companies: Downdraft: Bioneer (Finland).Updraft: Babcock & Wilcox Vølund A/S (Denmark), PMR Energy (USA).Two stage: Vinking TK (Denmark).

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FLUIDISED BED REACTORS:

Bubbling fluidised bed Circulating fluidised bed

• Status: several plants with > 20.000 operating hours.• Feedstock: Particle size between 1–100 mm. Ash may fuse with fluidising sand. • Capacity: CFB medium to large size (10 – 100 MW). BFB small to medium (1-25 MW)• Lower investment costs per unit of power: 2 – 4 Mill € / MW electric• Lower electricity production costs: 100 – 140 €/MWh.

• Companies: CFB: TPS (Sweden), Ahlstrom-Foster Wheeler (US), Battelle (US), Lurgi GmbH (Germany)BFB: Carbona Corporation (US).

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ENTRAINED FLOW REACTORS:

• High temperatures (>1200 °C)• Low particle diameter.• Pressurized operation simple.• Very low tar contents.y• Low methane content.• Currently for large scale and especially for synthesis process (methanol, Fischer-Tropsch) and hydrogen. • Much experience from coal gasification

Companies: Future Energy GmbH (Freiberg)Elcogás (Spain)

“Gasification is considered to be close to commercially available” various sources.

1.4 BIOMASS GASIFICATION TODAY. A few examples

Harboøre Plant, DenmarkUpdraft gasifierUpdraft gasifierCapacity: 1.000 kW electricExperience: more than 2x20.000 hours

Wiener Neustadt, Austria.Double fire gasifierCapacity: 550 kW electricE i b t 5 000 h

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Experience: about 5.000 hours

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Viking Gasifier, DenmarkTwo stage gasifierCapacity: 200 kW electricExperience: about 2.000 hours

Low-tech small scale gasifiers (China, India, etc).Usually downdraft or updraftCapacity: usually < 50-100 kW heat or electricExperience: several years

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Gasification Plant ENAMORA, SpainBubbling fluidised bed.Fuel: Almond shells and bagasse.Electric Power: 550 - 5.000 kW.Experience: 15.000 hours

Kymijärvi Lahti Gasification, FinlandCirculating Fluidised BedFuel: several different types of wastesCapacity: 60 MWfuelExperience: more than 40.000 hrs.

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Värnamo IGCC, SwedenIntegrated Gasification Combined Cycle (IGCC).Circulating Fluidised BedFuel: woodPower: 6 MWe electricity and 9 MWth heatExperience: 8.500 hours of operation.

ELCOGAS, Spain. I t t d G ifi ti C bi d C l (IGCC)Integrated Gasification Combined Cycle (IGCC).Entrained flow gasifier.Project for co-gasification of coal and 10 % biomass.Electrical Power: 300 MWe.Experience: 18.600 hours of operation.

Summary of commercial gasification plants in Europe (extracted from Hofbauer and Knoef, 2004)

Company Construction Cost (€) Technology Type of fuel Application

Energía Natural de Mora S.L.(Spain) 1996 1.100.000 BFB– motogenerator Almond shell Total power: 3500 kW.

Electric power: 750kW

Waste Gasification, Grève-in-Chianti , 1992 20.000.000 CFB Residues 40% plastics

+ 60 % paper

Total power: 30 MW.Electric power: 6.7 MW

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Italia + 60 % paper Extra gas for cement kiln

CHP-Plant Güssing, Austria 2001 8.700.000 CFB Lignocelulósic waste Total power: 8 MW.

Electric power: 2 MW

CHP-Plant Harboore, Denmark 2002 15.000.000 Fixed bed up-draft –

motogenerator Lignocelulósic waste Total power: 5 MW.Electric power: 1.4 MW

Kymiarvi Power Station, Lahti, Finland

1998 12.000.000 CFBOrganic waste

mixtures (paper, wood, plastics)

Total power: 70 MW.Electric power: 20 MW

CFB-Plant Rüdersdorf, Germany

1996 - CFB Biomass and organic residues

Total power:100 MW, para alimentación de cementera

SVZ Schwarze Fixed bed and entrained Waste biomass co- Methanol productionSVZ, Schwarze Pumpe Germany 1996 335.000.000 Fixed bed and entrained

flow. gasified with 20 % coal.

Methanol productionPotencia total: 420 MW

Värnamo Demonstration Plant, Sweeden

2000 25.000.000 Integrated Gasification Combined Cycle (IGCC)

Wood and lignocellulosic residues

Total power: 18 MW.Electric power: 6 MW

Carbo-Vâ-pilot (a)-plant Germany

1998 2.500.000 Carbo-V three step gasification

Lignocellulosic residues

Total power: 1 MW.Electric power: 150 kW

The Viking Gasifier, DTU, Denmark 2002 - Two stage fiexed bed Lignocellulosic

residuesTotal power: 70 kW.

Electric power: 17 kWBFB = bubbling fluidised bedCFB = circulating fluidised bed

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1.5 GAS CLEANING AND CONDITIONING.

OBJECTIVES:

- Reduce concentration of unwanted species: tars, VOC, particulates, SH2.

- Increase concentration of wanted species: calorific value, H2.

a) Products depending on type of reactor and operating conditions:

Reactor Temperature (ºC) Tars Particulates

Reaction Exit

Down-draft 1000 800 Very low medium

Up-draft 1000 250 Very high medium

Fluidised bed 850 850 Low high

p , 2

GASIFYING AGENTS AND PRODUCTS

BIOMASS GASIFYING AGENTS PRODUCTS

C ½ O2 CO

C H2O CO + H2

C CO2 2 CO

b) Requirements depending on intended application:

- Heat: low requirements regarding the presence of tars and other impurities.- Power: combustion engines and gas turbines require low tar, particulate and sulphur levels.- Chemical synthesis: very low content of impurities.

C CO2 CO

C 2 H2 CH4

C Air (21 % O2 + 78 % N2)

CO + N2

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GAS CLEANING AND CONDITIONING (2).

1) Physical removal of particulates, tars and other unwanted species (sulphur).2) Thermo-catalytic removal of VOC and tars reforming and cracking catalysts.3) Water Gas Shift to increase hydrogen content and reduce CO concentration.4) Preferential oxidation of CO to CO2. ) 25) Separation of unwanted gases from the mixture: CO2, N2.

SteamAir O2,

Fuel/ biomass

A B C

Air

1 2 3 4 5

Ash collection

Gasification reactor

Gas treatment.A: cyclone

B: filter

C: desulphuration

A B C

Reformer

Cracker

WGS

HTS.

WGS

LTS.

N2, CO2removal

PROX

H2

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REMOVAL OF TARS by THERMAL AND CATALYTIC METHODS

Tars: large molecular weight volatile compounds generated during the gasification of biomass. They condense at lower temperatures, blocking and fouling process equipments (valves, engines, turbines).

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J. Han, H. Kim (2008) The reduction and control technology of tar during biomass gasification/pyrolysis: An overview, Renewable and Sustainable Energy Reviews, 12 (2), Pages 397-416

L. Devi, K.J. Ptasinski, F. J. Janssen (2003) A review of the primary measures for tar elimination in biomass gasification processes, Biomass and Bioenergy, 24 (2), 125-140

D. Sutton, B. Kelleher, J. R. H. Ross (2001) Review of literature on catalysts for biomass gasification, Fuel Processing Technology, 73 (3), 155-173

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CATALYTIC CONDITIONING OF HOT GASES

REMOVAL OF TARS by THERMAL AND CATALYTIC METHODS (2)

• REFORMING CATALYSTS:Transition metals (mainly Ni) supported on alumina or other porous materials. Precious metals (Pt, Pd, Ru, Rh).

• CRACKING CATALYSTS:Acid solids: zeolites (ZSM-5, Y, Beta), mesostructured solids (Al-MCM-41, Al-SBA-15), active alumina.

CATALYSTS INSIDE GASIFICATION REACTOR

• Calcium and magnesium carbonates (dolomite, magnesite, lime). • Impregnation of biomass with alkaline metal salts (K2CO3, Na2CO3, NaCl, KCl, ZnCl2, AlCl3) • Increased conversion values and reduced formation of tars. • Limited catalytic activity compensated by low cost.

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1.6 CONCLUSSION WITH CONVENTIONAL BIOMASS GASIFICATION

“Gasification is considered to be close to commercially available” (Hofbauer and Knoef, 2005).

“At current biomass and capital cost levels, incentives are essential for a commercially viable biomass projects” (Bridgewater, 2002).

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Things to be considered: Capital investment: Operating and maintenance costs:Feedstock costs and availability:Market value of products:Risk and technical reliability:

PURPOSE OF GASIFICATION

GAS CLEANING AND CONDITIONING CAPITAL INVESTMENT ‐

MARKET PRICE OF PRODUCTS

ECONOMIC VIABILITY

OPERATING COSTSHEAT Tar and particulate removal ‐ low  Low  Low LimitedELECTRICITY Tar, particulate removal Medium Medium Limited

CHEMICALS AND H2

Tar, particulate removal

High High LimitedReformingWGSPSAPROX

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2. BIOMASS GASIFICATION FOR THE PRODUCTION OF ADSORBENTS

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2.1 INTRODUCTION TO ACTIVATED CARBONS:

a type of carbon that has been processed in order to develop an extended porosity (250-1000 cm3/g), surface area (500-2000 m2/g) and adsorption capacity.

- Demand in developed countries: 0 5-2 0 kg per person and year Growing at annual 3-4 %

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Demand in developed countries: 0.5 2.0 kg per person and year. Growing at annual 3 4 %.

- Average market price: bulk GAC: 0.75-2.0 € per kg

APLICATIONSliquid phase applications (79 %): potable water (37 %); industrial and municipal wastewater (21%); sugar decolourization (10 %); groundwater (8 %); household uses (6 %); food and beverage (5 %); mining (4 %); pharmaceuticals (3 %).

gas phase applications (21 %): air purification (40 %); automotive emission control (21 %); solvent vapour recovery (12 %); cigarette filter medium (8 %); miscellaneous (19 %).

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• PRODUCTION OF AC BY PHYSICAL ACTIVATION

Starting material

Carbonisation and Activation Classification Final AC

Conditioning, classification and grindingg g

Pelletizing drying Carbonisation:

400-550ºCInert conditions

Activation:900-1100ºCSteam or CO2.

Precursor Use (%)Wood 35Coke  28Lignite 14Peat 10Nut Shell 10Other 3

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• REACTORS FOR AC PRODUCTION

Moving bed reactors.

Rotary kiln.Multiple hearth furnace.

2.2 FEEDSTOCK FOR AC PRODUCTION

Abundant and cheap.Development of porosity during activation.High carbon content.Low ash content.

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Precursor Use (%)Wood 35Anthracite 28Lignite 14Peat 10Nut Shell 10

Mechanical strength for GAC.

“but almost any carbonaceous material may be used as AC precursor”.

Nut Shell 10Other 3

(Crini, 2006)

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(Ioannidou and Zabaniotou, 2007)

Raw Material S BET (m2/g) Vo (cm3/g) Yield (%)Apricot stones 1190 0.50 18Cherry stones 875 0.28 11Grape seeds 497 0.12 26Nut shells 743 0.21 18Pistachio nut shells 778 0.47Macadamia nut shells 1718 0.72Peanute hulls 420 0.17 30Almond shells 998 0.40 18Corn cob 960 0.49 29Olive stones 1550 65Rice Straw 2410 1.4Rice husks 480 1.3Sugarcane bagasse 452 17

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2.3 DEVELOPMENT OF POROSITY DURING GASIFICATION.

Typical AC yields: 15-30 wt%.

Carbon gasification in steam (SP 925) and CO2 (P 950 and P 1100) at different temperatures.

Development of porosity and surface area during gasification of carbon.

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3. GASIFICATION FOR THE COMBINED PRODUCTION OF ENERGY AND ADSORBENTS: CONSIDERATIONS AND PROPOSED TECHNOLOGY.

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3.1 PREVIOUS RESEARCH PROJECTS: thermal treatment of wastes for energy or adsorbents

(1) Title: Low-cost adsorbents from tyre rubber and other waste materials.

(2) Title: Thermal regeneration of field spent activated carbons.

(3) Title: Catalytic effects of metals during the thermal regeneration of granular activated carbon.

(4) Title: Adsorbent slow rate filters for the removal of colour and metals from upland potable waters.

(5) Title: Improvement of textural properties of zeolitic materials for their application as catalysts in chemicalreactions hindered by steric and difussional impediments.

(6) Title: Application of PY-GC/MS for the investigation of thermal and catalytic cracking of plastic polymers.

(7) Title: Development of thermal and catalytic processes for the recovery of plastic wastes.

(8) Title: Gasification of sewage sludge from urban water treatment plants.

BIOMASS Partial gasification

SYNGAS

ADSORBENTS

H2 CO

CH4 N2

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3.2 CONSIDERATIONS FOR DUAL PURPOSE

- Partial gasification of some types of biomass may favour the economic viability of the process.

SYNGAS

H2 CO

- REQUIREMENTS FOR ACTIVATED CARBON PRODUCTION:

Reactor should allow for recuperation of partially gasified char

BIOMASS Partial gasification

SYNGAS

ADSORBENTS

CH4 N2

Reactor should allow for recuperation of partially gasified char. Biomass should be able to produce high quality activated carbon.

- REQUIREMENTS FOR HIGH QUALITY GAS PRODUCTION:

Catalytic treatment of vapours required to ensure low tar contents.

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3.3 PROJECT OBJECTIVES

- To prove the gasification technology for the combined production of high quality syngas and activated carbon from biomass residues.

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SPECIFIC OBJETIVES

- WP 1: Assessment of biomass wastes with potential for being used for the combined production of energy and adsorbents: production, location, current use, economic value.

- WP 2: Chemical, physical and thermal characterization of these wastes.

- WP 3: Conventional gasification of biomass for the production of energy.

- WP 4: Gasification of biomass for the production of adsorbents.

- WP 5: Gasification of biomass for combined production of syngas and adsorbents (pilot scale tests).

- WP 6: Assessment of the economic viability, design of full scale plant.

4. CONCLUSIONS

- Partial gasification of biomass for the combined production of adsorbents and energy may be an advantageous approach to this technology.

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- In specific cases, activated carbon production may contribute to the economics of the gasification technology.

- The gasification technology needs to be adapted for this dual purpose and so do the operating conditions of the process.

Concluding remarks:

Low cost biomass is an appropriate feedstock for the production of energy by gasification.

But the activated carbons generated by partial gasification could be too valuable to be used as a source of energy.

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KEY ARTICLES

G. San Miguel, G. D. Fowler, C. J. Sollars (2003) A study of the characteristics of activated carbons produced by steam and carbon dioxide activation of waste tyre rubber, Carbon, Volume 41, Issue 5, Pages 1009-1016

G. San Miguel, S.D. Lambert, N.J.D. Graham (2006) A practical review of the performance of organic and inorganic adsorbents for the treatment of contaminated waters J Chem Technol Biotechnol 81 1685 1696

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adsorbents for the treatment of contaminated waters, J. Chem. Technol. Biotechnol., 81, 1685-1696

J.M. Dias, M.C.M. Alvim-Ferraz, M.F. Almeida, J.R.Rivera-Utrilla, M. Sánchez-Polo (2007) Waste materials for activatedcarbon preparation and its use in aqueous-phase treatment: A review, Journal of Environmental Management, 85(4):833-46.

H. Hofbauer, H. Knoef (2005) "Success Stories on Biomass Gasification"; in: "Handbook biomass gasification", BTG, 115 -161.

G. Crini (2006) Non-conventional low-cost adsorbents for dye removal: A review, Bioresource Technology, Volume 97, Issue 9, Pages 1061-1085

O. Ioannidou, A. Zabaniotou (2007) Agricultural residues as precursors for activated carbon production—A review, Renewable and Sustainable Energy Reviews, Volume 11, Issue 9, Pages 1966-2005

T. Bridgewater (2002) The future for biomass pyrolysis and gasification: status, opportunities and policies for Europe, European Commission, Altener contract 4.1030/S/01-009/2001, http://ec.europa.eu/energy/res/publications/doc1/report_p536_v2.pdf

K. Maniatis (2002) Progress in biomass gasification. European Commission, http://ec.europa.eu/energy/res/sectors/doc/bioenergy/km_tyrol_tony.pdf

Manahan S. E., Enriquez-Poy M., Tan Molina L., Durán C. (2007) Energy and activated carbon production from cropbiomass byproducts, in Towards a Cleaner Planet Energy for the Future, SpringerLink, ISBN 354071345X