1. New mild combustion experience in oxy-combustion
The possibility to perform a Combustion Process without a flame front (Mild Combustion) have been largely investigated in a high diluted oxidant condition as focal conditioning parameter.
Further investigations also carried out at CCA (Combustion research Combustion Centre) have demonstrated that it is obtainable in pressurized oxy combustion with low FGR to control the combustion temperature.
Then, the main conditioning parameter to obtain mild combustion is more precisely defined by the temperature homogeneity and, consequently, by heat transfer control.
As already presented at HiTACG in ESSEN >>>>

2. « Volume combustion » HiTACG, MILD,flameless, FLOX®, diluted …
or « volume » Combustion
Traditional combustion
Che cosa c’enra
Flame front: very
high temperature
Uniform high temperature
Low temperature zones

3. Smooth gradients And “volume combustion”
Focusing on….
Smooth gradients And “volume combustion”
Non linear systems, “with more then three Catastrophic parameters are, by definition, Chaotic, i.e. they can be described statistically only”
Flames are, by definition, chaotic system
The lowering of gradients, by order of magnitudes, of catastrophic parameters moderates the system chaotic nature
Comburent-fuel dilution with fumes by a flue gas recycling (lowering reactans concentration gradient) is an important feature for combustion reaction moderation (chemical uniformity)
Preheating of reactans (by a heat recycling) is an important feature for temperature gradient moderation
Volume combustion is the targeted solution

4. ISOTHERM 5MW pilot at CCA
ISOTHERM® POWER Approach:
High temperature OXY-Combustion Chamber;
Under pressure Combustion run;
Large heat capacity of the system and fast feed back control;
Heat recovery by steam generation;
Only simplified final flue gas treatment.

5. ISOTHERM® Demonstration Unit aerial view
Oxygen Tank
T-quench
Blower
Flue-gas Post treatment
Reactor
Boiler

6. New perspective in Gas Turbine Application
New environmental issue will drive to very important challenge:
To reduce pollutant emission in terms of: NOx; CO but also VOC; Sub micron particle; heavy metals; etc..
To be able to perform higher efficiency
To be able of a wide range of fuels use
To be CCS ready

7. Trends in power plants
Thermodynamics
Power Plant Concept
General Trends in the Development of Power Plant Technologies
Processes and technologies like CO2-free Power Plants, FuelCells and Combination-Cycle-Processes
efficiency
Further development of Steam-and-Gas-Combination-Processes
and the Coal-Power Generation e.g. IGCC, STIG, HAT
Ultra-supercritical Steam-Cycle-Processes
Rerum Cognitio
WDK-Process
Rerum Cognitio
WDK-Process
Courtesy of WDK-process

8. How Gas turbine can answer this challenge
Mild Combustion can be obtained considering the integration of actual already developed features as:
ceramic bricks lined combustion chamber that reduce cold exposed surfaces;
Steam injection in combustion (STIG Cycle) that introduce opacity in IR radiation transfer helping uniformity in temperature
Higher temperature in turbine inlet also using steam cooling

9. Benefits of the “Mild Combustion” in Gas Turbine Application
Easy treatment of very variable products composition as Low calorific Gasses or Hydrogen
Strongly reduced pollutant impact: (NOx<3ppm; VOC and organic sub - micron particles strongly reduced)
High temperature uniformity at Turbine inlet

10. Steam in Combustion
As we know in STIG cycle steam help to increase efficiency but also to get mild combustion
It is a low cost pressurized fluid if the latent heat can be recovered
What happen if in a TG the air compressor is replaced by a boiler and the oxidant will be injected in double stream with the fuel ???

11. Thermodynamic efficiency improvements
e.g. assume a standard cycle plus a topping one consisting in an internal heating of the fluid

12. Ambitious challenge expect the future of combustion in power generation
High efficiency
Free choice of low quality fuels;
Zero emission;
CO2 caption;
The “Mild Combustion” can represent a very important solution for the future.