Biomass derived chars for energy applications. (July 2019)

• Record Type: Journal Article
• Authors: Khiari, Besma; Jeguirim, Mejdi; Limousy, Lionel; Bennici, Simona
• Is Part Of: Renewable & sustainable energy reviews. Volume 108(2019)
• Page Start: 253
• Page End: 273
• Publication Date: 2019-07
• Subjects: Biomass derived chars -- Energy recovery by combustion -- Syngas -- Catalyst -- Hydrogen production -- Tar reforming -- Gas storage -- Electrochemical storage; HHV High Heating Values -- HHVt High heating value of the product -- HHV0 High heating value of the feed -- Ti ignition temperature -- Tf temperature corresponding to the maximum burning rate -- Mt mass of the product at time t -- M0 initial mass of the feed -- db dry basis -- EC Electric Conductivity -- TG Thermogravimetry -- DTG Derivative Thermogravimetry -- Vmax maximum burning rate -- Tf temperature of the maximum burning rate -- FR Fuel Ratio -- CI Combustibility Index -- VI Volatile Ignitability -- Di Ignition index -- S combustion characteristic index -- ηM mass yield ratio -- ηE energy yield ratio -- PM Particulate Matter -- HC hydrocarbons -- NOx nitrogen oxides -- PAH Polycyclic aromatic hydrocarbons -- CSR Coke Strength after Reaction -- CRI Coke Reactivity Index -- VM Volatile Matter -- BF Blast Furnace -- BDF Biomass Derived Fuel -- RDF Refuse Derived Fuel -- CGE Cold Gas Efficiency -- HE Hot Gas Efficiency -- CCE Carbon Conversion Efficiency -- ECE Energy Conversion Efficiency -- SER Specific Energy Requirements -- msyngas mass flow rate of syngas -- Msyngas molar mass of syngas -- mfuel mass flow rate of feedstock -- LHVsyngas and LHV fuel calorific values of product gas and feedstock -- Ydry gas dry gas yield -- Cp specific heat capacity -- Tf temperature at the gasifier exit -- T0 temperature of the fuel (feedstock) entering the gasifier -- P plasma torch power -- AC Activated Carbon -- BET Brunauer-Emmett-Teller -- SSA Specific Surface Area -- Vμ microporous volume -- DCFC Direct Carbon Fuel Cell -- MCFC Molten Carbonate Fuel Cells -- PEMFC Proton-Exchange Membrane Fuel Cells -- MFC Microbial Fuel Cell; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.rser.2019.03.057
• Languages: English
• ISSNs: 1364-0321

Abstract

Abstract: Biomass-derived chars present energy density values close to those of fossil fuels and therefore they are good candidates in electricity or heat production plants with only minor drawbacks compared to fossil fuels. Even if co-firing seems the most attractive solution for near-term applications, processes based on combustion and gasification (which are competing in dependence of the need of heat or electricity) are receiving renewed attention. Thanks to their high carbon content, and their high specific surface area and developed porous structure, biomass-derived chars can be treated and converted into activated carbons and applied in many different field (as energy storage materials for gaseous fuels, mainly hydrogen and methane, or as electrodes). They can constitute the raw materials for preparing synthetic graphite, which can be used in some types of batteries and fuel cells, and in carbon electrodes for electrochemical capacitors. The performances in terms of capacitance, electrical conductivity, potential, charge and discharge rates, power density, etc. have been reported to be very close to those of commercial devices. The recent progress in the activation protocols brought to higher fuel gas storage capacities, especially in cryogenic conditions and under high pressure, and opened the possibility to apply these materials in new application fields. In catalysis, advances in the use of biomass-derived chars and active carbons have been made thanks to the improvement of the modification techniques. The optimization of the engineering methodologies allows to lower the cost of the activation processes of biomass-derived chars and to tune the char properties to adapt them to the final application. The present paper aims to give a comprehensive survey of already-well-established or future potential energy applications of biomass-derived chars. A critical comparison of their use in different processes is reported and their modification by various catalytic, physical and chemical routes is detailed. Highlights: Competition of combustion and gasification in energy recovery from chars. Tar, oil and hydrocarbon reforming increase the chars' energy recovery output. Chars can be applied as adsorbents in fuel-gas storage systems. Char based electrodes ensure good performances in electrochemical storage systems. Chars can be used as catalysts in green energy applications.