Jean-Michel Commandré

Cirad - La recherche agronomique pour le développement | CIRAD · Unité Propre de Recherche Biomasse, Bois, Énergie, Bioproduits (BioWooEB)

Thailand is an agriculture-based country. It produces large amounts of open burned agricultural residues. A strategy to use them as biofuel all year round is to enhance their fuel properties by coupling blending and thermochemical pre-treatment. In this study, the pyrolytic behaviour of major residues (napier grass, rice straw, cassava stalks and c...

The objective of this work is to compare mass loss and chemical evolution of the solid phase, versus time, during dynamic torrefaction of different types of biomass. For this purpose, two experiments, ThermoGravimetric Analysis and solid-state 13C Cross-Polarization/Magic Angle Spinning Nuclear Magnetic Resonance, were run on four representative bi...

New PHBV/wheat straw fibres biocomposites were produced in such a way to improve the fibre/matrix interface and modulate functional properties of materials. A torrefaction treatment was applied to wheat straw fibres in such a way to increase their hydrophobicity. This improvement led to a better fibre/matrix interfacial adhesion in resultant compos...

An extensive characterization was carried out on various biomass samples representative of the diversity in France, including forestry samples (softwood and hardwood woodchips, eucalyptus and poplar short rotation coppices), very short rotation coppices (VSRC) samples and agricultural samples (wheat straw, triticale, fescue, miscanthus and switchgr...

Torrefaction is a mild thermal pretreatment which improves biomass properties and releases condensable species. Condensable species released during torrefaction of pine, ash wood, miscanthus and wheat straw at 250, 280 and 300 °C were investigated. A fixed-bed reactor was used for the laboratory scale experiments. A micro-GC, Karl Fischer titrator...

Raw biomass grinding is a highly energy‐intensive step due to the fibrous structure of the material. Torrefaction, which enables the partial destruction of this fibrous structure through mild thermal treatment, appears as an attractive option. In this work, a complete quantification of species released during torrefaction was performed on four vari...

This study focused on the effect of a wood char on tar cracking and reforming in the context of fluidized-bed gasification. Phenol was used to create in situ a mixture representative of tars produced by pyrolysis and gasification in a dual fluidized-bed reactor. The wood char was placed in a fixed-bed reactor, and atmospheres composed of H2 and ste...

Pyrolysis plays a major role in the optimization of process efficiency and gas quality in two-stage gasifiers. We developed an original reactor at pilot scale to investigate continuous fixed bed pyrolysis, in either allothermal or autothermal operating mode using air injection. Instrumentation and analysis enabled thermal profiles to be established...

This study describes tar conversion on olivine in fluidized-bed gasification conditions. A laboratory-scale reactor (Aligator) was used to characterize phenol conversion to higher tars, before adding a sand and olivine bed to investigate heterogeneous steam reforming and the cokefaction of these tars. H2 and H2O atmospheres were tested both separat...

This study describes tar conversion on olivine in fluidized-bed gasification conditions. A laboratory-scale reactor (Aligator) was used to characterize phenol conversion to higher tars, before adding a sand and olivine bed to investigate heterogeneous steam reforming and the cokefaction of these tars. H2 and H2O atmospheres were tested both separat...

In this study, pyrolysis process of wood bio-oil was studied. The effects of temperature in the range 550– 1000 �C, heating rate in the range 2–2000 �C s�1 and ash content of the bio-oil on char, tar and gas yields were investigated. The main gas species generated are quantified by Micro-GC: H2, CO, CO2, CH4 and trace amounts of C2H4 and C2H6. A te...

Torrefaction is a thermal treatment used to improve the properties of biomass in relation to thermo-chemical processing techniques for energy generation. It is a thermo-chemical treatment method primarily characterized by an operating temperature within the 200–300 °C range. It is carried out under conditions of atmospheric pressure and in the pres...

Fast pyrolysis of biomass is a promising process for the preparation of bio-oil dedicated to energy production. Inorganic species originally present in biomass are known to induce problems such as bio-oil instability or deposits and fouling. However the mechanisms of inorganic species release during biomass pyrolysis into the raw bio-oils still rem...

Bamboo has wide range of moisture content, low bulk energy density and is difficult to transport, handle, store and feed into existing combustion and gasification systems. Because of its important fuel characteristics such as low ash content, alkali index and heating value, bamboo is a promising energy crop for the future. The aim of this study was...

The pyrolysis of wood was carried out in an Entrained Flow Reactor at high temperature (650 to 950 °C) and under rapid heating conditions (> 103 K s− 1). The influence of the diameter and initial moisture of the particle, reactor temperature, residence time and the nature of the gaseous atmosphere on the composition of the gaseous products has been...

Biomass gasification is gaining attention as a route for biomass energy production. When large scale units are considered, bio-oil shows lots of advantages compared to solid biomass such as high energy volume density and easy handling and storing. Syngas (H2 and CO) can be produced from bio-oil by two gasification processes, also called reforming p...

Torrefaction is a way to treat biomass before transportation or thermochemical conversion. It can be used to increase the energy content of wood or to facilitate grinding. The purpose of this paper was to quantify the impact of such a treatment on the behaviour of wood during gasification by steam at high temperature to produce syngas. The aspects...

This study aims to experimentally characterize the carbonaceous and nitrogenous species, from the flash pyrolysis of millet stalks and polyethylene plastic bags, using the device of the tubular kiln, coupled to two gas analyzers: Analyzer Fourier Transform Infrared (FTIR) and an analyzer Infrared Non-Dispersive (IRND). Gaseous products analyzed are...

This work analyzes and discusses the general features of biomass pyrolysis, both on the basis of a new set of experiments and by using a detailed kinetic model of biomass devolatilization that includes also successive gas phase reactions of the released species and is therefore able to predict the main gases composition. Experiments are performed i...

Ligno-cellulosic biomass from different sources presents very variable compositions. Consequently, there is a wide variation in the nature and quantities of gaseous products obtained after thermal treatment of biomasses.The objective of this work is to establish a link between the composition of a biomass and its pyrolysis gas yields and compositio...

Ligno-cellulosic biomass from different sources presents variable composition. The main aim of this work was to develop a method to predict the gas yields after flash pyrolysis (and tar cracking) at 950 °C in an Entrained Flow Reactor of any biomass from its composition in the three main components – cellulose, hemicellulose and lignin.For this app...

La gazéification étagée couplée à un moteur à gaz est une technologie prometteuse pour la production d'électricité décentralisée de petites et moyennes puissances. L'objectif de ces travaux était de concevoir, dimensionner et construire un nouveau réacteur expérimental pour caractériser l'étape de gazéification des procédés à lit fixe et étagé. Le Réa...

Experiments are performed in an entrained flow reactor to better understand the kinetic processes involved in biomass pyrolysis under high temperatures (1073–1273K) and fast heating condition (>500Ks−1). The influence of the particle size (0.4 and 1.1mm), of the temperature (1073–1273K), of the presence of steam in the gas atmosphere (0 and 20vol%)...

The combustion of solid fuels in the rotary kiln and in the calciner of a cement plant generates fuel and thermal NO. This NO can be reduced inside the reducing zone of the calciner. This occurs in two different ways: homogeneous reduction by hydrocarbons and heterogeneous reduction by char. The purpose of this paper is to identify the relative con...

Quicklimes produced in an industrial kiln have a very low hydration activity compared to those produced in the laboratory. In this study, we seek to explain these differences in reactivities by providing quantitative data on the kinetics of the two mechanisms involved in the production of quicklime: the calcination of limestone to produce quicklime...

We describe here a new experimental device developed for the study of a combustion front propagation in a reactive medium: crushed oil shale (500 to 1000 µm). We are interested in the propagation of a front supplied by air in co-current. The cell is a vertical cylinder of 90mm internal diameter and 300mm height, made up of an insulating material. T...

A numerical 2D model of a thermal recuperative incinerator (TRI) used to oxidise volatile organic compounds (VOCs) diluted in an air flow was developed to simulate the coupled equations for flow, heat transfer, mass transfer and progress of chemical reactions. The model was confronted with experimental values obtained on a highly instrumented half-...

This work establishes quantitative links between the operation parameters—plus one geometrical parameter—and the gas pollutant emissions of a recuperative incinerator (RI) of volatile organic compounds (VOCs). Using experimental design methodology, and based on a large number of experiments carried out on a half-industrial-scale pilot unit, mathema...

Combustion of solid fuels at 800-1000°C releases fuel NO that may be reduced either by homogeneous reactions with hydrocarbons or heterogeneous char reduction. The solid combustion starts with devolatilisation that releases volatiles, mainly CO and hydrocarbons from hydrogen to tars. A petcoke and a coal are here first pyrolyzed under nitrogen, at...

The reactivity toward O2 of six petcokes with vanadium content between 0.05% and 0.26% has been assessed using both thermogravimetry (TG) and an entrained flow reactor (EFR). Very high reactivities were observed in TG experiments as compared with typical reactivities for carbon found in the literature. The reactivities are correlated with the vanad...

This work is an attempt to establish links between the properties of the petcoke that can be measured through standard analysis in the laboratory and the behaviour of the petcoke both in terms of its combustion velocity and the emission of gas pollutants.A large number of petcokes, 22, taken from different sources, were burnt in an Entrained Flow R...

In a cement plant precalciner, petroleum cokes are burned between 800 and 1100°C and NO present in the flue gas is mainly fuel NO. We have developed a thermochemical model that describes the combustion of powdered petroleum coke in laminar flow conditions. It takes into account the main thermal and chemical mechanisms which occur during combustion....

This work demonstrates the possibility of reducing NO emissions from an “in vein” gas burner using a simple and easy to operate technique: the addition of air or of an inert gas to the burner fuel gas feed. A reduction by 30% can be obtained with air; more than 60% of NO can be avoided using an inert gas. Several interpretations are proposed to exp...

Petroleum cokes are widely used in cement plants for energy generation. Because of their very low volatile content, the physicochemical processes occurring during their combustion should be mainly controlled by heterogeneous reactions. The reactivities of some petroleum cokes toward NO between 800 and 1000 °C have been characterized through experim...

The reaction with air of a large number (22) of high-sulphur petroleum cokes was studied by temperature-ramped thermogravimetric analysis. The kinetic parameters for each coke were established, based on BET surface areas. The oxidation rates (kgC m−2 s−1 atm−1) were found to vary with sample mass. This was a result of limitations on oxygen transfer...

Le précalcinateur de cimenterie est un réacteur dans lequel une grande quantité d'énergie thermique est produite par la combustion de solides pulvérisés à des températures modérées : 800 à 1100°C. Les cokes de pétrole sont la principale source d'énergie. Nous nous intéressons dans ce travail aux mécanismes thermochimiques qui sont à l'origine de la...

Four pyrolyzed carbonaceous materials were reacted with 950 ppm of nitric oxide (in N2) in an entrained flow furnace at temperatures between 800 and 1,000°C. Their apparent reactivities, corrected for mass transfer, when calculated on a BET area basis displayed a wide spread of values. However, when recalculated for the surface area estimated for p...