Wet combustion and its performance 232 .pdf pages
Thesis presented with a view to obtaining the title of Doctor from the University Henri Poincaré, Nancy 1 in Mechanical and Energy Science. By Rémi GUILLET.
Keywords: wet combustion / combustion / humidity / hygrometry / environment / efficiency / energy / thermal process / nitrogen oxides / protection
For many years, water has been used as an additive to improve combustion, improve machine power, and even as an anti-knock and, more recently, as an inert to reduce the formation of nitrogen oxides. Today the challenge to be taken up concerns the economy of the scarce resource that is fossil energy and even more, the protection of the environment.
With the wet combustion, the performance of land based gas turbines can be enhanced very significantly Thus, steam injection cycles (STIG), regenerative cycles to humidified air (HAT), can approach the performance of the combined cycle.
For its part, the water vapor pump cycle which recycles the ultimate, sensible and latent heat, usually released to the chimney, in the form of preheated and humidified combustion air, allows many processes to approach efficiency. maximum combustion of 100% of the higher calorific value of the fuel.
In all its forms, the introduction of water into the combustion chambers is also known to reduce the formation of NOx: direct injection, in emulsion with the fuel, in vapor form generated by a recuperator, a water vapor pump ...
So remarkable energy and environmental performance are possible,
especially for processes that enhance the recovery of latent heat. Among the most likely to benefit from the advantages of the wet combustion processes, of:
- condensing boilers;
- direct contact generators;
-the direct dryers with energy recovery;
- regenerative cogeneration turbines;
- clean incineration processes with energy recovery.
In wet combustion, three fluids are introduced into the combustion chamber: fuel, combustion air and additional water ...
To analyze these processes, we have developed an analysis method using the
wet bulb temperature as the main parameter, called Diagram of Hygrometric
Combustion. This method, described in detail and numerous diagrams derived therefrom, is recommended for:
-analysis, forecasting, improvement, optimization of combustion efficiency;
- predictive control;
- prediction of condensation;
- the sizing of two-phase exchangers.
But the method can also be used in the case of traditional processes such as boilers and condensing generators to offer prospects of access to efficiency with more precision and at lower cost.
Further information on changes due to the presence of additional water in thermal combustion processes is also provided.