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A solution for CCS (Carbon Dioxide Capture and Sequestration of CO2) is oxycombustion. Due to the high cost of pure O2 production, however, other approaches recently emerged such as post-combustion coupled with Oxygen Enhanced Air (OEA). This is the solution studied in this paper, which presents an innovative gas turbine cycle, the Oxygen Enriched Air Steam Injection Gas Turbine Cycle (OEASTIG). The OEASTIG cycle is composed of Methane combustion with OEA (Oxygen Enhanced Air), EGR (Exhaust Gas Recirculation) and H2O coming from a STIG (Steam Injection Gas Turbine). CO2 capture is achieved by a membrane separator. The final aim of this work is to predict NO and CO emissions in the gas turbine by experimental and numerical approaches. Before carrying out this study, the validation of a reaction mechanism is mandatory. Moreover, this new gas turbine cycle impacts on the combustion zone and it is therefore necessary to understand the consequences of H2O and CO2 dilution on combustion parameters. While a large number of papers deal with CO2 dilution, only a few papers have investigated the impact of water dilution on methane combustion. A study of the influence of H2O dilution on the combustion parameters by experimental and numerical approaches was therefore carried out and is reported in the present paper. The paper is divided in three parts: i) description of the innovative gas turbine (OEASTIG) cycle and determination of the reactive mixtures compatible with its operation; ii) validation of the reaction mechanism by comparing laminar methane flame velocity measurements performed in a stainless steel spherical combustion chamber with calculations carried out in a freely propagating flame using the Chemical Workbench v.4.1. Package in conjunction with the GRIMech3.0 reaction mechanism; iii) Extrapolation to gas turbine conditions by prediction of flame velocities and determination of the feasible conditions from a gas turbine point of view (flame stability). In particular, mixtures (composed of CH4/O2/N2/H2O or CO2) leading to the same adiabatic temperature were investigated. Lastly, the influence of oxygen enrichment and H2O dilution (compared to CO2 dilution) were investigated.

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A differential mathematical model has been developed for the simulation of the ammonia-water absorption refrigeration system ROBUR ® , model ACF60-00 LB. The model, with modular structure, contains the governing equations based on mass, species, and energy, implemented for the main system components. The model captures both thermal and mass resistance in the mass and transfer processes that simultaneously occur in the system. A calculation procedure is presented to evaluate the performance of the cooling system under offdesign conditions, when driven by hot water temperature ranging between 160 and 210 ºC. Performance of the system when the ambient temperature is up to 40ºC has been analysed, assumed that the pumped solution flow rate kept constant, and the high-pressure level may be used as a control strategy. Results show that, at ambient temperature of 40ºC, the cooling capacity of the is restricted by the size of the air-coolant absorber if the feed hot water temperature is 210ºC. However, difficulties in condenser operation reduce the cooling capacity of the system when the temperature of the feed water drops to 160ºC. In addition, at ambient temperature of 40ºC and feed water temperature of 210ºC, geometry restriction due to the rectifier and the solution-cooled absorber results in COP increase. In such working conditions, the refrigeration system operates at its maximum high-pressure level.