The effect of natural gas composition and atmospheric humidity on premixed combustion across the regions of Colombia

As a tropical and highly mountainous country, Colombia has varying levels of atmospheric humidity across its regions. These humidity levels affect combustion parameters in premixed combustion systems such as laminar burning velocity, adiabatic flame temperature, and pollutant emissions. The greatest effect of water in the reaction zone is the reduction of NOx formation (at equilibrium) by up to 40% through the thermal mechanism for lean mixtures. The laminar burning velocity is reduced by up to 25% at an equivalence ratio of 0.5 and a molar moisture content of 3.5%. This effect is reduced near the stoichiometric point due to the higher adiabatic flame temperature. The natural gas mixtures from the Cusiana and Guajira fields were analyzed. The same combustion property changes were obtained for both fuels when the reaction zone water content was varied. However, the Cusiana gas had a higher absolute flame temperature, laminar flame speed, and pollutant emissions than the Guajira gas, due to its greater heavy hydrocarbon content. This work presents the analysis and the resulting favorable-combustion map for the regions of Colombia. Therein is shown that Bogotá and its surroundings are the most prone to NOx emissions due to the region’s low atmospheric moisture content; less than 1.5% molar fraction. As a consequence, this area should implement tightened emissions monitoring and regulation. In contrast, the Atlantic coast and the Magdalena river valley are the regions of Colombia that have the best conditions for combustion due to their high moisture content; greater than 3.5% molar fraction. This makes them the preferred regions for the installation of combustion systems and thermal power generation plants from the point of view of minimizing operational instabilities and pollutant emissions. For example, at high pressure and temperature, the humidity has an appreciable effect on the laminar flame speed, reducing it by up to 25% at the equivalence ratio of 0.5. This effect lessens as the mixture shifts towards the stoichiometric point due to the higher adiabatic flame temperature.