The injection of water into an engine or a hydrocarbon combustion cycle is beneficial in terms of both pollution control and cycle efficiency.
This is called: "wet combustion".
Rémi Guillet, Doctor of Science, has made a doctoral dissertation supported in 2002 to download here: "Wet combustion and its performance" by Rémi Guillet
Summary of R.Guillet's thesis:
For many years, water has been used as an additive to improve combustion, the power of machines, even as an antiknock then, more recently, as an inert allowing the reduction of 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 heat, sensitive and latent, usually discharged 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 ...
Then, remarkable energy and ecological performances are possible, especially for the processes that value the recovery of latent heat. Among the processes most likely to benefit from the benefits of wet combustion are:
- condensing boilers;
- direct contact generators;
- direct dryers with energy recovery;
- regenerative turbines in cogeneration;
- 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 temperature as the main parameter, called the Hygrometric Combustion Diagram. This method, presented in detail as well as numerous diagrams which result from it, is to be recommended for:
-analysis, forecasting, improvement, optimization of combustion yields;
- predictive control;
- forecasting of condensation;
- the design 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 perspectives of access to efficiency with more precision and at lower cost.
Other information on changes due to the presence of additional water in thermal combustion processes is also provided.
- Download the full thesis "Wet combustion and its performance" by Rémi Guillet
- Download a synthesis on the combustion in humid air
– Explanations and analyzes on wet combustion on our forums
– All downloads