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Catalytic ozonation is a promising method for simultaneous removal of NO x and Cl-VOCs, but needs to clarify their interaction mechanism and the influence of catalyst acidity. In this paper, the simultaneous catalytic ozonation of NO and dichloromethane (DCM) on Mn/H-ZSM-5 molecular sieve catalysts were investigated experimentally. Results show that the overall acidity, acid sites type and intensity have a significant impact on the degradation efficiency, the conversion path of Cl element, and the interaction of NO/DCM adsorption-degradation. Nevertheless, regardless of catalysts, NO could be preferentially oxidized by ozone to generate NO 2 in co-ozonation process, which inhibited and even shielded DCM ozonation at O 3 /DCM ratio <1.7. In addition, the highly active oxidizing species such as NO 3 /N 2 O 5 , produced by the deep ozonation of NO 2 , exhibited a synergistic effect on the conversion of DCM and intermediates, which in turn weakened NO 2 deep oxidation. Specifically, NO addition caused a general decrease in the HCl selectivity, and a slight increase in the CHCl 3 selectivity of all samples, while the Cl 2 selectivity was determined by the overall catalyst acidity. The samples with higher overall acidity exhibited lower activity for DCM degradation. In particular, for samples with the weak overall acidity but strong acid sites, the sum selectivity of HCl, Cl 2 , and CHCl 3 was significantly improved under the interplay effect of NO, indicating that strong acidic sites were beneficial to the complete degradation of DCM. In-situ DRIFTS revealed that aldehydes and carboxylates were the key intermediates of DCM ozonation. In the co-ozonation, NO and its oxidation products (such as nitrates) could promote the formation and conversion of these intermediates, and further converted into CO and CO 2 by the active oxidant from ozone. Finally, the interference of H 2 O and SO 2 on the NO/DCM co-ozonation were revealed. [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of NO is necessary for the environment but the present adopted NH 3 -SCR has its weaknesses. This paper proposes CH 4 -SCR of NO with perovskite catalyst (La 0.8 Sr 0.2 MnO 3 /α-Al 2 O 3 ) and experiments were done to study the effect of key factors (resident time, temperature and the initial O 2 concentration). XRD patterns and SEM image show that La 0.8 Sr 0.2 MnO 3 is a catalyst with perovskite structure and this kind of structure has been proved to be efficient in SCR. Experiments show that CH 4 can convert NO efficiently in association with catalyst La 0.8 Sr 0.2 MnO 3 /α-Al 2 O 3 and the max NO conversion ratio is over 90%. The longer the resident time is, the higher the conversion of NO is. The conversion of NO increased with the increase of temperature when the initial concentration of O 2 ranged from 0% to 3% and moderate O 2 at high temperatures can promote the reduction of NO by filling oxygen vacancies in lattice and taking part in the reactions. The new catalyst La 0.8 Sr 0.2 MnO 3 /α-Al 2 O 3 could work efficiently in the widest range of oxygen concentration at 800   °C and it reached 90% with the oxygen concentration ranging from 4% to 6%. This research will provide further data to improve the process of SCR in the power plant. [ABSTRACT FROM AUTHOR]

A Lean Premixed Prevaporized (LPP) low-emission combustor which is applied with the combustion technology of staged lean fuel is developed. To study the cold flow dynamics and the combustion performance of the LPP combustor, both experimental tests using the Particle Image Velocimetry (PIV) to quantify the flow dynamics and numerical simulation using the Fluent software are conducted respectively. To investigate the emissions of the LPP combustor, four kinds of inlet conditions (viz. 7%, 30%, 85% and 100% F∞ (Thrust Force)) were conducted using numerical simulation. Numerical results are in good agreement with the experimental data. Results show that:1) a Primary recirculation zone (PRZ), a Corner recirculation zone (CRZ) and a Lip recirculation zone (LRZ) exist in the LPP combustor, and the velocity gradients between pilot swirling flow and primary swirling flow have contributed to the exchanges of mass, momentum and energy. 2) With the decrease of thrust force, NO mass fraction, CO2 mass fraction and total pressure losses at the exit of LPP combustor fall gradually. 3) Thermal NO formation rate closely relate to the zone area where gas temperature overruns 1900K and the maximum temperature in LPP combustor. 4) The combustion performance of the LPP combustor proposed in this paper is very well, and through comparative analysis with four kins of typical gas tubine combustor, the NO emission is very low and is equivalent to the CAEP6 43.87%. [ABSTRACT FROM AUTHOR]

The paper presents the numerical simulation on combustion of methane and biogas mixtures in the swirl burner can-Type of gas turbine combustion chamber. The study deals with the impact of mass fraction of carbon dioxide for biogas on emissions of noxious compounds during combustion. The investigations were done for four different fuels: pure methane (100% CH4), three biogases (90%CH4+10%CO2, 75%CH4+25%CO2 and 70%CH4+30%CO2), with the constant value of equivalence ratio (ɸ = 0.95). The numerical results show that a low content of carbon dioxide in methane-air mixture leads to a better flame stability through an increase of the volume of the recirculation zone. The numerical analysis has shown that the biogas fuel allows a reduction of about 33% on the NO emissions and about 10% on the CO emissions and carbon dioxide contained in the fuel leads to the lowering of the flame temperature, whose effect reduces NO emissions. The results of the investigation clearly demonstrate that it is possible to use such fuels in combustion systems with swirl burners. [ABSTRACT FROM AUTHOR]

The paper presents the numerical simulation on combustion of methane and biogas mixtures in the swirl burner can-Type of gas turbine combustion chamber. The study deals with the impact of mass fraction of carbon dioxide for biogas on emissions of noxious compounds during combustion. The investigations were done for four different fuels: pure methane (100% CH4), three biogases (90%CH4+10%CO2, 75%CH4+25%CO2 and 70%CH4+30%CO2), with the constant value of equivalence ratio (ϕ = 0.95). The numerical results show that a low content of carbon dioxide in methane-air mixture leads to a better flame stability through an increase of the volume of the recirculation zone. The numerical analysis has shown that the biogas fuel allows a reduction of about 33% on the NO emissions and about 10% on the CO emissions and carbon dioxide contained in the fuel leads to the lowering of the flame temperature, whose effect reduces NO emissions. The results of the investigation clearly demonstrate that it is possible to use such fuels in combustion systems with swirl burners. [ABSTRACT FROM AUTHOR]

Depending on CO 2 capture processes or hydrocarbon sources, fuel gas from boilers can be accompanied with impurities which could be co-injected in a geological storage. These gases, such as SOx, NOx, or oxygen could interact with reservoir fluids and rocks and well materials and could affect the safety of the storage. However, there are currently only few data on the behavior of such gas mixtures, as well as on their chemical reactivity, especially in the presence of water. The purpose of this paper is to develop experimental and analytical protocols in order to acquire new thermodynamic data on SO2 and NO under geological conditions of pressure and temperature using Raman spectrometry. [ABSTRACT FROM AUTHOR]

Abstract: Regarding the hydrocarbon source and CO2 capture processes, fuel gas from boilers may be accompanied by so-called “annex gases” which could be co-injected in a geological storage. These gases, such as SOx, NOx, or oxygen for instance, are likely to interact with reservoir fluids and rocks and well materials (casing and cement) and could potentially affect the safety of the storage. However, there are currently only few data on the behaviour of such gas mixtures, as well as on their chemical reactivity, especially in the presence of water. One reason for this lack comes from the difficulty in handling because of their dangerousness and their chemical reactivity. Therefore, the purpose of the “Gaz Annexes” project was to develop new experimental and analytical protocols in order to acquire new thermodynamic data on these annex gases, in fine for predicting the behaviour of a geological storage of CO2 + co-injected gases in the short, medium and long terms. This paper presents the mail results from the “Gaz Annexes” project concerning acquisition of PVT experimental and pseudo-experimental data to adjust and validate thermodynamic models for water/gas/salts mixtures as well as the possible influence of SO2 and NO on the geological storage of CO2. The “Gaz Annexes” project gives new insights for the establishment of recommendations concerning acceptable content of annex gases. [Copyright &y& Elsevier]

Abstract: The direct implementation into CFD codes of large kinetic mechanisms for the prediction of pollutant emissions is still unfeasible, due to computer time limitations which become particularly relevant when considering the typical scale of the industrial applications. Therefore, simplified modeling approaches are generally adopted, as they allow reducing the computational effort associated with the numerical simulations. With regard to NO formation, simple one-step mechanisms are used to describe each of the relevant routes contributing to the overall generation of NO, i.e., thermal, prompt. The main drawback associated to a simplified NO formation approach lies, however, in the extreme sensitivity of the lumped rates on the thermo chemical state which define the combustion system of interest. Then, a proper description of turbulence/chemistry interactions must be employed in the CFD model, to provide a realistic background for the estimation of NO emissions. This becomes particularly important in MILD combustion regime, which generally requires an accurate description of the gas-phase oxidation, due to the kinetic control on the overall combustion process. The present paper discusses key aspects and requisite for predicting NO formation in MILD combustion regime. The approach is based on the direct coupling of simplified NO mechanisms to the CFD calculation and is applied to different MILD conditions. Simulations are carried out for a set of experimental runs performed on a self-recuperative MILD burner, varying the hydrogen content in the fuel stream from 0% up to 50% by wt. [ABSTRACT FROM AUTHOR]