Research Projects

Due to the ever-increasing fossil fuel consumption and resulting pollution, the push for alternative fuels is stronger than ever. Hydrogen has a huge potential to replace hydrocarbon- based energy technologies with a cleaner option. Although the gravimetric energy density of hydrogen (120 MJ.kg) is the highest among fuels, the volumetric energy density is very low (8 MJ/l) since gaseous hydrogen is very light. The wide flammability range (4-75%) of hydrogen in air also makes storage and leakages a serious issue. This leads to the exploration of hydrogen-carriers such as ammonia, methanol, hydrazine as possible fuels in combustion applications. Ammonia is a colourless gas at standard atmospheric conditions with a calorific value of 30 MJ/kg and can be stored as a liquid at slightly higher pressures (~10 bar at room temperatures) or lower temperatures (-33 oC at atmospheric pressure). It also has the highest hydrogen content of all carriers. These advantages have led to various groups across the world looking into ammonia combustion in practical applications. Of the many demerits of ammonia is its low flammability (15-25% in air) and high NOx pollution potential. The latter is primarily due to the Fuel-NOx pathway in addition to Thermal-NOx. A possible way of tackling the low flammability of ammonia is hydrogen addition. The presence of hydrogen enhances the flame stability while also increasing the heat output. It also helps in mitigating ammonia leakage (unburnt ammonia at the combustor exit). Since hydrogen storage is a concern and ammonia is easily stored, in-situ cracking of ammonia is a possible solution. This indicates decomposition of a fraction of ammonia to H2/N2 and mixing the same with ammonia as fuel to the combustor. Most combustion devices are sources of heat energy, which can be utilised for heating incoming fuel/air to the combustion chamber. At temperatures of ~ 800 oC cracking of ammonia can be achieved in the presence of catalysts such as Ru, Ni and even Fe. Hence it is worthwhile to study the design of a combustor with an integrated catalytic ammonia cracker to demonstrate the possibility of operation. Such a combustor might have applications in mobility (land/air) and stationary power generation as well.