Academic literature on the topic 'Volatiles (CO2-H2O)'

High-temperature H2O and CO2 can improve the pyrolysis behavior of oil shale. Therefore, in this paper, Jimusar oil shale was selected as the research object and the effect of the reaction atmosphere (H2O, CO2, and N2) on its pyrolysis behavior, pyrolysate distribution, and pyrolysis oil quality was fully compared and studied. The results showed that compared with the N2 atmosphere, the presence of H2O and CO2 both increased the weight loss and weight loss rate during pyrolysis of oil shale and the existence of H2O advanced the initial precipitation temperature of volatiles by 17°C. The comprehensive release characteristic indices of volatiles during pyrolysis of oil shale in the CO2 and H2O atmospheres increased by 49.34% and 114.35%, respectively, which significantly improved its pyrolysis reactivity. Both H2O and CO2 atmospheres improved the pyrolysis oil yield of oil shale, and the pyrolysis oil yield in the H2O atmosphere performed better than that in the CO2 atmosphere. Especially, the H2O atmosphere could increase the pyrolysis oil yield by 41.42%. The existence of CO2 prevented methyl radicals from accepting hydrogen radicals during pyrolysis and reduced the alkane yield, while CO2 participated in the addition reaction of alkane, which increased the alkene yield. High-temperature H2O provided more hydrogen source, which increased the alkane yield and inhibited the alkene formation. Both H2O and CO2 atmospheres promoted the cracking of polycyclic aromatics and increased the yield of small-molecular aromatics in the pyrolysis oil. During the pyrolysis process of oil shale, CO2 and H2O underwent reforming reaction with the heavy oil, which increased the light component fraction, thereby increasing the H/C ratio of pyrolysis oil. Thus, the existence of H2O and CO2 atmospheres improved the quality of pyrolysis oil and the effect of H2O was better than CO2. The H2O and CO2 atmosphere promoted the formation of a well-developed pore structure, which was conducive to mass and heat transfer during pyrolysis of oil shale.

Context. The ESA Rosetta mission investigated the environment of comet 67P/Churyumov-Gerasimenko (hereafter 67P) from August 2014 to September 2016. One of the experiments on board the spacecraft, the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) included a COmet Pressure Sensor (COPS) and two mass spectrometers to analyze the composition of neutrals and ions, the Reflectron-type Time-Of-Flight mass spectrometer (RTOF), and the Double Focusing Mass Spectrometer (DFMS). Aims. RTOF species detections cover the whole mission. This allows us to study the seasonal evolution of the main volatiles (H2O, CO2, and CO) and their spatial distributions. Methods. We studied the RTOF dataset during the two-year long comet escort phase focusing on the study of H2O, CO2, and CO. We also present the detection by RTOF of O2, the fourth main volatile recorded in the coma of 67P. This work includes the calibration of spectra and the analysis of the signature of the four volatiles. We present the analysis of the dynamics of the main volatiles and visualize the distribution by projecting our results onto the surface of the nucleus. The temporal and spatial heterogeneities of H2O, CO2, and CO are studied over the two years of mission, but the O2 is only studied over a two-month period. Results. The global outgassing evolution follows the expected asymmetry with respect to perihelion. The CO/CO2 ratio is not constant through the mission, even though both species appear to originate from the same regions of the nucleus. The outgassing of CO2 and CO was more pronounced in the southern than in the northern hemisphere, except for the time from August to October 2014. We provide a new and independent estimate of the relative abundance of O2. Conclusions. We show evidence of a change in molecular ratios throughout the mission. We observe a clear north-south dichotomy in the coma composition, suggesting a composition dichotomy between the outgassing layers of the two hemispheres. Our work indicates that CO2 and CO are located on the surface of the southern hemisphere as a result of the strong erosion during the previous perihelion. We also report a cyclic occurrence of CO and CO2 detections in the northern hemisphere. We discuss two scenarios: devolatilization of transported wet dust grains from south to north, and different stratigraphy for the upper layers of the cometary nucleus between the two hemispheres.

The combustion mechanism of bio-oil derived from wood fast pyrolysis was investigated by thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TG–FTIR) in flowing air. The results show that the combustion process of bio-oil consists of two main consecutive stages at a low heating rate. The combustion reaction becomes more and more intense from the first to the second stage. The release of volatiles occurs mainly at 80～200 °C and 350～500°C, and the gaseous products in each stage are different. The main products in the first stage are H2O with a few low molecule weight compounds, such as methanol, formic acid, etc. In the second stage, some new volatiles such as CO2, CO and CH4, etc. are present. Among the above volatiles, CO2 is the dominant gaseous product in the whole combustion process. The concentrations of CO2 and CO keep increasing, and reach the maximum at about 450 °C. Over 570°C, there are few products released at the end of the combustion process.

Reconstruction of the mechanisms of carbonatitic melt evolution is extremely important for understanding metasomatic processes at the base of the continental lithospheric mantle (CLM). We have studied the interaction between garnet lherzolite and a carbonatitic melt rich in molecular CO2 and H2O in experiments at 6.3 GPa and 1200–1450 °C. The interaction with garnet lherzolite and H2O-bearing carbonatite melt leads to wehrlitization of lherzolite, without its carbonation. Introduction of molecular CO2 and H2O initiates carbonation of olivine and clinopyroxene with the formation of orthopyroxene and magnesite. Partial carbonation leads to the formation of carbonate–silicate melts that are multiphase saturated with garnet harzburgite. Upon complete carbonation of olivine already at 1200 °C, melts with 27–31 wt% SiO2 and MgO/CaO ≈ 1 are formed. At 1350–1450 °C, the interaction leads to an increase in the melt fraction and the MgO/CaO ratio to 2–4 and a decrease in the SiO2 concentration. Thus, at conditions of a thermally undisturbed CLM base, molecular CO2 and H2O dissolved in metasomatic agents, due to local carbonation of peridotite, can provide the evolution of agent composition from carbonatitic to hydrous silicic, i.e., similar to the trends reconstructed for diamond-forming high density fluids (HDFs) and genetically related proto-kimberlite melts.

The focus of present study is on Codium bursa collected from the Adriatic Sea. C. bursa volatiles were identified by gas chromatography and mass spectrometry (GC-FID; GC-MS) after headspace solid-phase microextraction (HS-SPME), hydrodistillation (HD), and supercritical CO2 extraction (SC-CO2). The headspace composition of dried (HS-D) and fresh (HS-F) C. bursa was remarkably different. Dimethyl sulfide, the major HS-F compound was present in HS-D only as a minor constituent and heptadecane percentage was raised in HS-D. The distillate of fresh C. bursa contained heptadecane and docosane among the major compounds. After air-drying, a significantly different composition of the volatile oil was obtained with (E)-phytol as the predominant compound. It was also found in SC-CO2 extract of freeze-dried C. bursa (FD-CB) as the major constituent. Loliolide (3.51%) was only identified in SC-CO2 extract. Fatty acids were determined from FD-CB after derivatisation as methyl esters by GC-FID. The most dominant acids were palmitic (25.4%), oleic (36.5%), linoleic (11.6%), and stearic (9.0%). FD-CB H2O extract exhibited better antifungal effects against Fusarium spp., while dimethyl sulfoxide (DMSO) extract was better for the inhibition of Penicillium expansum, Aspergillus flavus, and Rhizophus spp. The extracts showed relatively good antifungal activity, especially against P. expansum (for DMSO extract MIC50 was at 50 µg/mL).

Context. Cometary outgassing is induced by the sublimation of ices and the ejection of dust originating from the nucleus. Therefore measuring the composition and dynamics of the cometary gas provides information concerning the interior composition of the body. Nevertheless, the bulk composition differs from the coma composition, and numerical models are required to simulate the main physical processes induced by the illumination of the icy body. Aims. The objectives of this study are to bring new constraints on the interior composition of the nucleus of comet 67P/Churyumov-Gerasimenko (hereafter 67P) by comparing the results of a thermophysical model applied to the nucleus of 67P and the coma measurements made by the Reflectron-type Time-Of-Flight (RTOF) mass spectrometer. This last is one of the three instruments of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA), used during the Rosetta mission. Methods. Using a thermophysical model of the comet nucleus, we studied the evolution of the stratigraphy (position of the sublimation and crystallisation fronts), the temperature of the surface and subsurface, and the dynamics and spatial distribution of the volatiles (H2O, CO2 and CO). We compared them with the in situ measurements from ROSINA/RTOF and an inverse coma model. Results. We observed the evolution of the surface and near surface temperature, and the deepening of sublimation fronts. The thickness of the dust layer covering the surface strongly influences the H2O outgassing but not the more volatiles species. The CO outgassing is highly sensitive to the initial CO/H2O ratio, as well as to the presence of trapped CO in the amorphous ice. Conclusions. The study of the influence of the initial parameters on the computed volatile fluxes and the comparison with ROSINA/RTOF measurements provide a range of values for an initial dust mantle thickness and a range of values for the volatile ratio. These imply the presence of trapped CO. Nevertheless, further studies are required to reproduce the strong change of behaviour observed in RTOF measurements between September 2014 and February 2015.

Abstract Volatiles, such as carbon and water, modulate the Earth's mantle rheology, partial melting and redox state, thereby playing a crucial role in the Earth's internal dynamics. We experimentally show the transformation of goethite FeOOH in the presence of CO2 into a tetrahedral carbonate phase, Fe4C3O12, at conditions above 107 GPa—2300 K. At temperatures below 2300 K, no interactions are evidenced between goethite and CO2, and instead a pyrite-structured FeO2Hx is formed as recently reported by Hu et al. (2016; 2017) and Nishi et al. (2017). The interpretation is that, above a critical temperature, FeO2Hx reacts with CO2 and H2, yielding Fe4C3O12 and H2O. Our findings provide strong support for the stability of carbon-oxygen-bearing phases at lower-mantle conditions. In both subducting slabs and lower-mantle lithologies, the tetrahedral carbonate Fe4C3O12 would replace the pyrite-structured FeO2Hx through carbonation of these phases. This reaction provides a new mechanism for hydrogen release as H2O within the deep lower mantle. Our study shows that the deep carbon and hydrogen cycles may be more complex than previously thought, as they strongly depend on the control exerted by local mineralogical and chemical environments on the CO2 and H2 thermodynamic activities.

Abstract Magmatic systems are dominated by five volatiles, namely H2O, CO2, F, Cl, and S (the igneous quintet). Multiple studies have measured partitioning of four out of these five volatiles (H2O, CO2, F, and Cl) between nominally volatile-free minerals and melts, whereas the partitioning of sulfur is poorly known. To better constrain the behavior of sulfur in igneous systems we measured the partitioning of sulfur between clinopyroxene and silicate melts over a range of pressure, temperature, and melt composition from 0.8 to 1.2 GPa, 1000 to 1240 °C, and 49 to 66 wt% SiO2 (13 measurements). Additionally, we determined the crystal-melt partitioning of sulfur for plagioclase (6 measurements), orthopyroxene (2 measurements), amphibole (2 measurements), and olivine (1 measurement) in some of these same run products. Experiments were performed at high and low oxygen fugacities, where sulfur in the melt is expected to be dominantly present as an S6+ or an S2– species, respectively. When the partition coefficient is calculated as the total sulfur in the crystal divided by the total sulfur in the melt, the partition coefficient varies from 0.017 to 0.075 for clinopyroxene, from 0.036 to 0.229 for plagioclase, and is a maximum of 0.001 for olivine and of 0.003 for orthopyroxene. The variation in the total sulfur partition coefficient positively correlates with cation-oxygen bond lengths in the crystals; the measured partition coefficients increase in the order: olivine < orthopyroxene < clinopyroxene ≤ amphibole and plagioclase. At high oxygen fugacities in hydrous experiments, the clinopyroxene/melt partition coefficients for total sulfur are only approximately one-third of those measured in low oxygen fugacity, anhydrous experiments. However when the partition coefficient is calculated as total sulfur in the crystal divided by S2– in the melt, the clinopyroxene/melt partition coefficients for experiments with melts between ~51 and 66 wt% SiO2 can be described by a single mean value of 0.063 ± 0.010 (1σ standard deviation about the mean). These two observations support the hypothesis that sulfur, as S2–, replaces oxygen in the crystal structure. The results of hydrous experiments at low oxygen fugacity and anhydrous experiments at high oxygen fugacity suggest that oxygen fugacity has a greater effect on sulfur partitioning than water. Although the total sulfur clinopyroxene-melt partition coefficients are affected by the Mg/(Mg+Fe) ratio of the crystal, partition coefficients calculated using S2– in the melt display no clear dependence upon the Mg# of the clinopyroxene. Both the bulk and the S 2– partition coefficients appear unaffected by IVAl in the clinopyroxene structure. No effect of anorthite content nor of iron concentration in the crystal was seen in the data for plagioclase-melt partitioning. The data obtained for orthopyroxene and olivine were too few to establish any trends. The partition coefficients of total sulfur and S 2– between the crystals studied and silicate melts are typically lower than those of fluorine, higher than those of carbon, and similar to those of chlorine and hydrogen. These sulfur partition coefficients can be combined with analyses of volatiles in nominally volatile-free minerals and previously published partition coefficients of H2O, C, F, and Cl to constrain the concentration of the igneous quintet, the five major volatiles in magmatic systems.

Les processus volcanologiques sont gouvernés par de nombreux paramètres physiques et chimiques (pression, température, composition chimique. . . ) qui exercent une grande influence sur les propriétés physiques des liquides silicatés (i. E. Magmatiques). Cependant, l'effet des volatils (gaz dissous) reste très mal connu. Leur présence dans les magmas joue pourtant un rôle primordial sur la fragmentation, le dégazage et le transport de ceux-ci. Les effets du CO2 et de H2O sur les propriétés rhéologiques (densité, viscosité, dilatation thermique) sont étudiés sur un liquide silicaté synthétique simple pour CO2, et sur un liquide basaltique pour H2O, le basalte étant la roche magmatique la plus répandue sur la surface de la Terre. L'ensemble des résultats obtenus permet une meilleure compréhension de l'interaction eau-magma en fonction de la chimie et apporte des résultats nouveaux quant à l'effet du CO2 dissous. Volcanological processes are governed by many physical and chemical parameters such as pressure, temperature and chemical composition, bubble and crystal content. . . These parameters are known for exerting a stong influence on the physical properties of silicate melts (i. E. Magmas). However, the effects of dissolved volatiles is still poorly understood, although their presence play an essential role in fragmentation, degassing and magma transport. The effects of CO2 and H2O, the two most abundant volatiles in magmas, are investigated, on the rheological properties (density and volume, viscosity, and thermal expansion) of a simple synthetic silicate melt for CO2, ans a basaltic melt for H2O, basalt being the most widely spread composition on the surface of the planet. The results allow a much better comprehension of the water/magma interactions depending on chemical composition, and bring new data regarding the effect of dissolved CO2

Volatiles are a fundamental component of the Magmatic-Hydrothermal model of platinum group element (PGE) ore deposition for PGE deposits in layered mafic intrusions such as Bushveld and Stillwater. Volatiles have the potential to complex with PGEs in silicate melts and hydrothermal fluids, increasing PGE solubility; in order to assess the models of PGE ore deposition reliable estimates on the solubilities in the various magmatic phases must be known. However, experimental studies on the solubility and partitioning behaviour of PGEs in mafic magmatic-hydrothermal systems under relevant conditions are sparse, and the data that do exist produce conflicting results and new or adapted experimental methods must be applied to investigate these systems. Experimental results are presented here, investigating the effect of volatiles (i.e. H2O, Cl and CO2) on Pt and Ir solubility in a haplobasaltic melt and fluid-melt partitioning of Pt between an aqueous fluid and a haplobasaltic melt under magmatic conditions using a sealed-capsule technique. Also included are the details of the development of a novel experimental technique to observe fluid-melt partitioning in mafic systems and application of the method to the fluid-melt partition of Pt. Solubility experiments were conducted to assess the effect of volatiles on Pt and Ir solubility in a haplobasaltic melt of dry diopside-anorthite eutectic composition at 1523K and 0.2GPa. Synthetic glass powder of an anhydrous, 1-atm eutectic, diopside-anorthite (An42-Di58) haplobasalt composition was sealed in a platinum or platinum-iridium alloy capsule and was allowed to equilibrate with the noble metal capsule and a source of volatiles (i.e. H2O, H2O-Cl or H2O-CO2) at experimental conditions. All experiments were run in an internally-heated pressure vessel equipped with a rapid quench device, with oxygen fugacity controlled by the water activity and intrinsic hydrogen fugacity of the autoclave (MnO-Mn3O4). The resultant crystal- and bubble-free run product glasses were analyzed using a combination of laser ablation ICP-MS and bulk solution isotope-dilution ICP-MS to determine equilibrium solubilities of Pt and Ir and investigate the formation and contribution of micronuggets to overall bulk determined concentrations. In water-bearing experiments, it was determined that water content did not have an intrinsic effect on Pt or Ir solubility for water contents between 0.9 wt. % and 4.4 wt. % (saturation). Water content controlled the oxygen fugacity of the experiment and the resulting variations in oxygen fugacity, and the corresponding solubilities of Pt and Ir, indicate that over geologically relevant conditions both Pt and Ir are dissolved primarily in the 2+ valence state. Pt data suggest minor influence of Pt4+ at higher oxygen fugacities; however, there is no evidence of higher valence states for Ir. The ability of the sealed capsule technique to produce micronugget-free run product glasses in water-only experiments, allowed the solubility of Pt to be determined in hydrous haplobasalt at lower oxygen fugacities (and concentrations) then was previously observed. Pt and Ir solubility can be represented as a function of oxygen fugacity (bars) by the following equations: [Pt](ppb)= 1389(fO-sub-2)+7531(fO-sub-2)^(1/2) [Ir](ppb)=17140(fO-sub-2)^(1/2) In Cl-bearing experiments, experimental products from short run duration (<96hrs) experiments contained numerous micronuggets, preventing accurate determination of platinum and iridium solubility. Longer run duration experiments showed decreasing amounts of micronuggets, allowing accurate determination of solubility; results indicate that under the conditions studied chlorine has no discernable effect on Pt solubility in the silicate melt from 0.6 to 2.75 wt. % Cl (saturation). Over the same conditions, a systematic increase in Ir solubility is found with increasing Cl content; however, the observed increase is within the analytical variation/error and is therefore not conclusive. If there is an effect of Cl on PGE solubility the effect is minor resulting in increased Ir solubilities of 60% at chlorine saturation. However, the abundance of micronuggets in short run duration experiments, which decreases in abundance with time and increases with Cl-content, offers compelling evidence that Cl-bearing fluids have the capacity to transport significant amounts of Pt and Ir under magmatic conditions. It is suggested that platinum and iridium dissolved within the Cl-bearing fluid are left behind as the fluid dissolves into the melt during the heating stages of the experiment, leaving small amounts of Pt and Ir along the former particle boundaries. With increasing run duration, the metal migrates back to the capsule walls decreasing the amount of micronuggets contained within the glass. Estimates based on this model, using mass-balance calculations on the excess amount of Pt and Ir in the run product glasses (i.e. above equilibrium solubility) in short duration experiments, indicate estimated Pt and Ir concentrations in the Cl-bearing fluid ranging from tens to a few hundred ppm, versus ppb levels in the melt. Respective apparent (equilibrium has not been established) partition coefficients (D,fluid-melt) of 1x10^3 to 4x10^3 and 300-1100 were determined for Pt and Ir in Cl-bearing fluids; suggesting that Cl-bearing fluids can be highly efficient at enriching and transporting PGE in mafic magmatic-hydrothermal ore-forming systems. Platinum solubility was also determined as a function of CO2 content in a hydrous haplobasalt at controlled oxygen fugacity. Using the same sealed capsule techniques and melt composition as for H2O and Cl, a hydrous haplobasaltic melt was allowed to equilibrate with the platinum capsule and a CO2-source (CaCO3 or silver oxalate) at 1523 K and 0.2 GPa. Experiments were conducted with a water content of approximately 1 wt. %, fixing the log oxygen fugacity (bars) between -5.3 and -6.1 (log NNO = -6.95 @ 1573 K and 0.2 GPa). Carbon dioxide contents in the run product glasses ranged from 800-2500 ppm; and over these conditions, CO2 was found to have a negligible effect on Pt solubility in the silicate melt. Analogous to the Cl-bearing experiments, bulk concentrations of Pt in CO2-bearing experiments increased with increasing CO2 content due to micronugget formation. Apparent Pt concentrations in the H2O-CO2 fluid phase, prior to fluid dissolution, were calculated to be 1.6 to 42 ppm, resulting in apparent partition coefficients(D,fluid-melt) of 1.5 x 10^2 to 4.2 x 10^3, increasing with increasing mol CO2:H2O up to approximately 0.15, after which increasing CO2 content does not further increase partitioning. As well, a novel technique was developed and applied to assess the partitioning of Pt between an aqueous fluid and a hydrous diopside-anorthite melt under magmatic conditions. Building upon the sealed-capsule technique utilized for solubility studies, a method was developed by adding a seed crystal to the capsule along with a silicate melt and fluid. By generating conditions favourable to crystal growth, and growing the crystal from the fluid, it is possible to entrap fluid inclusions in the growing crystal, allowing direct sampling of the fluid phase at the conditions of the experiment. Using a diopside seed crystal with the diopside-anorthite eutectic melt, it was possible to control diopside crystallization by controlling the temperature, thus allowing control of the crystallization and fluid inclusion entrapment conditions. Subsequent laser ablation ICP-MS analysis of the fluid inclusions allowed fluid–melt partition coefficients of Pt to be determined. Synthetic glass powder of an anhydrous, 1-atm eutectic, diopside-anorthite (An42¬Di58) haplobasalt composition (with ppm levels of Ba, Cs, Sr and Rb added as internal standards), water and a diopside seed crystal were sealed in a platinum capsule and were allowed to equilibrate at experimental conditions. Water was added in amounts to maintain a free fluid phase throughout the experiment, and the diopside crystal was separated from the melt. All experiments were run in an internally heated pressure vessel equipped with a rapid-quench device, with oxygen fugacity controlled by the water activity and intrinsic hydrogen fugacity of the autoclave (MnO-Mn3O4). Experiments were allowed to equilibrate (6-48 hrs) at experimental conditions (i.e. 1498K, 0.2 GPa, fluid+melt+diopside stable) before temperature was dropped (i.e. to 1483K) to induce crystallization. Crystals were allowed to grow for a period of 18-61 hours, prior to rapid isobaric quenching to 293K at the conclusion of the experiment. Experimental run products were a crystal- and bubble-free glass and the diopside seed crystal with a fluid-inclusion-bearing overgrowth. Analysis of fluid inclusions provides initial solubility estimates of Pt in a H2O fluid phase at 1488 K and 0.2 GPa at or near ppm levels and fluid melt partition coefficients ranging from 2 – 48. This indicates substantial metal enrichment in the fluid phase in the absence of major ligands such as carbonate or chlorine. The results of this study indicate that the volatiles studied (i.e. H2O, CO2, and Cl) do not have a significant effect on Pt and Ir solubility in a haplobasaltic melt at magmatic conditions. These results suggest that complexing of Pt and Ir by OH, Cl, and carbonate species in a haplobasaltic melt is insignificant and the presence of these volatiles will not result in significantly increased PGE contents over their dry counterparts, as has been suggested. Preliminary evidence of minor Cl-complexing of Ir is presented; however, resulting in only a slight increase (<100%) in Ir solubility at Cl-saturation. Significant partitioning of Pt and Ir into a fluid phase at magmatic conditions has been demonstrated; with estimates of fluid-haplobasaltic melt partition coefficients increasing from 1x10^1 for pure water to up to an apparent 4x10^3 with the addition of Cl or CO2 to the system. This result indicates complexing of Pt and Ir with OH< HxCOy≤ Cl. Using these estimates, Cl- or CO2-bearing magmatic fluids can be highly efficient at enriching and transporting platinum group elements (PGEs) in mafic magmatic-hydrothermal ore-forming systems.

Wildfires are a growing threat, especially in Mediterranean climate areas during periods of drought. Wildfire research community continues to investigate propagation mechanisms on a large scale considering the thermal and fluid mechanics effects, or the main fire emissions (CO, CO2, H2O, H2, CH4). However, research on the effect of abiotic stresses on the plant emission during wildfires remains lacking, despite the fact that Mediterranean are considered important BVOC emitting and storing species. This article addresses the effect of combined hydric and thermal stresses on the volatile’s emission behaviours of two important Mediterranean shrub species; Rosmarinus officinalis and Cistus albidus that are largely consumed in wildfires. Different levels of hydric stress were applied on plants of the two species in a greenhouse of the EBI laboratories of the University of Poitiers. Thermal stress was executed by placing the water stressed plants inside a hermetic enclosure equipped with a radiant panel of maximal radiant heat flux of 84kW.m-2 and a fire-resistant glazed window for visualisation. The gaseous emissions of the plants under thermal stresses were collected and analysed by two complementary devices: an instantaneous gas analyser for CO, CO2, H2 and CH4, and adsorbent tubes by using the techniques of adsorption and desorption (by pyrolysis) for emission collection and analyses, respectively. Simultaneous Py/GC-MS experiments were realised at IC2MP on a foliar scale of the water stressed plants in order to gain more control and precision in emission analyses. The heating tests showed a good reproducibility for pyrolyses of leaf samples and interesting variations between the monoterpene emissions of stressed and unstressed plants. At plant scale, number of tests for each plant species at a given hydric stress level were insufficient to give trends and strong results because of some imposed technical problems and the constraints of public health crisis. However, these tests allowed us to adapt experimental protocols and devices for further testing such as: plant location and fixation, heat flux ramp, sampling location, use of adsorbent tubes, hydric stress duration and normalisation of measured concentrations according to the plant size.

Radiation heat transfer is the dominant model of heat transfer in the large scale industry boiler, especially in oxy-fuel combustion condition. Radiative properties of combustion gases and char oxidation in the oxy-fuel condition are obviously different from the air-fuel combustion, due to the N2 replaced by CO2. Through researchers proposed many helpful correlations based on the air-fuel Weighted-Sum-of-Grey-Gases-Model (WSGGM), the absorption coefficients were commonly constant or correlations were discrete by the classical molar ratio of H2O to CO2 (MR), which were mismatching the continuous value of MR in the real furnace. Meanwhile, the discrete MR is also not applied to the computational fluid dynamics (CFD). In this paper, new correlations for the WSGGM are determined as polynomial function of MR and temperature, which can be conveniently employed in Fluent by the form of user-defined-functions in C language. Parameters of model are fitted by total emittances calculated based on the timely HITEMP 2010 database. New correlations are validated by comparing the emittances with line-by-line calculations and other classical models. New correlations are employed in the CFD for the real industrial oxy-fuel combustion with the temperature range of 400–2600K, pressure path-length between 0.01 and 60 bar m. Several assumed test cases have been investigated to evaluate the accuracy of the models. Modified correlations for WSGGM give a better accuracy of the total emittances for the mixed combustion gases in the real furnace. New models including radiative and chemical reaction mechanisms have been employed to CFD modeling of combustion process for a tangentially fired 300MWe utility boiler. The industrial boiler is modeled by a partition meshing method with the hexahedral structured mesh. Due to the atmosphere shift from N2 to CO2, three aspects are essential to be modified for oxy-fuel: radiation model, char oxidation model and homogeneous volatile oxidation model. To investigate the performance of the furnace, air-fuel combustion selected as the conference, three other cases employed are defined as Oxy21 (vol21%, O2), Oxy26 (vol26, O2) and Oxy29 (vol29%, O2), respectively. Temperature profile and heat transfer are investigated for the different test cases. Meanwhile, the simulation and calculation heat transfer in the furnace are also compared. The results show the new modified simulation has an approximate 4–11% lower than the thermodynamic calculation. To achieve an identical heat flux and temperature distributions with the air-fuel case, the molar fraction 29% of O2 is essential for the selected implementation. (CSPE)