Use of carbon footprint to assess CO2 and N2O emissions during the production of nitrogen fertilizers

Fertiliser production makes a significant contribution to energy consumption and greenhouse gas emissions. The analysis of emission factors was carried out on a data set spanning from 2013 to 2015 for the whole chain of fertiliser production from raw materials up to the final products - ammonium nitrate, ammonium sulphate, urea in prilled form and liquid fertilisers based on them. The carbon footprint was calculated in compliance with the Standard ISO 14067:2013. The calculations were based on the gate-to-gate analysis. Analysis showed carbon footprint reduction after technological modifications - modernisation of a Benfield section, for example, absorption of gaseous CO2 in propylene carbonite and potassium carbonite solutions, with the recovery of the pure CO2, resulting in reduction of energy consumption from 35.3 to 33.3 GJ/Mg NH3 - change of the N2O decomposition catalysts, resulting in reduction of N2O emission factor from 2 to 0.9 kg N2O/Mg HNO3. Life cycle assessment is a useful tool, which can be used in the decision-making process for factory modernisation and improvement the production processes.