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
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
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.
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
11/09/2008
2
1. CONVENTIONAL BIOMASS GASIFICATION.
3
Wood gasification plant at Güssing (Austria) Laboratory scale gasifier.
• 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.
• 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.
• 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
Kymijärvi Lahti Gasification, FinlandCirculating Fluidised BedFuel: several different types of wastesCapacity: 60 MWfuelExperience: more than 40.000 hrs.
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.
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
11/09/2008
9
17
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
18
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
11/09/2008
10
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).
19
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
20
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.
11/09/2008
11
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).
21
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
22
2. BIOMASS GASIFICATION FOR THE PRODUCTION OF ADSORBENTS
11/09/2008
12
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 %
23
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 %).
24
• 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
11/09/2008
13
25
• 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.
26
Precursor Use (%)Wood 35Anthracite 28Lignite 14Peat 10Nut Shell 10
Mechanical strength for GAC.
“but almost any carbonaceous material may be used as AC precursor”.
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.
11/09/2008
15
3. GASIFICATION FOR THE COMBINED PRODUCTION OF ENERGY AND ADSORBENTS: CONSIDERATIONS AND PROPOSED TECHNOLOGY.
29
30
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
11/09/2008
16
31
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.
11/09/2008
17
3.3 PROJECT OBJECTIVES
- To prove the gasification technology for the combined production of high quality syngas and activated carbon from biomass residues.
33
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.
34
- 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.
11/09/2008
18
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
35
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