Environmental impact assessment of green ammoniacoupled with urea and ammonium nitrate production.

This study aims to explore more sustainable ammonia production routes for urea and ammonium nitrate fertilizers to support the rising global food demand and help achieve the Net Zero Emissions scenario by 2050. The research uses process modelling tools and Life Cycle Assessment methodology to evaluate the technical and environmental performance of green ammonia production compared to blue ammonia production, both pathways coupled with urea and ammonium nitrate production processes. The blue ammonia scenario uses steam methane reforming for H2 production, while the sustainable approach scenarios consider water electrolysis with renewable resources (i.e., wind, hydro and photovoltaics) and nuclear power as a carbon-free source for H2 generation. The study assumes an annual productivity of 450,000 tons for both urea and ammonium nitrate. The environmental assessment uses mass and energy balance data derived from process modelling and simulation. A cradle-to-gate environmental evaluation is conducted using GaBi software and the Recipe 2016 impact assessment method. Results show that green ammonia production requires less raw materials but has higher energy consumption due to electrolytic H2 production (i.e., >90% of total energy requirements). The use of nuclear power achieves the highest reduction in global warming potential (i.e., 5.5 times for urea and 2.5 times for ammonium nitrate production processes), while hydro power coupled with electrolytic H2 production shows lower environmental impacts in most categories (i.e., six out of ten impact categories). Overall, the sustainable scenarios prove to be suitable alternatives for fertilizer production towards achieving a more sustainable future.

Environmental impact assessment of post-combustion CO2 capture technologies applied to cement production plants.

Decarbonizing the cement manufacturing sector presents an interesting and pressing challenge as it is one of the largest energy consumers in industry (i.e., 7%), emitting considerable amounts of anthropogenic carbon dioxide (i.e., 7%). This paper performs a technical and environmental assessment of decarbonisation of cement production through process modelling and simulation, thermal integration analysis, and Life Cycle Assessment (LCA). Integration of three post-combustion capture methods for a conventional cement plant with an annual productivity of one million tons and a carbon capture rate of 90% is evaluated in comparison to the reference case without carbon capture and storage (CCS). Mass and energy balances derived from simulations are used for the assessment of three innovative capture systems: reactive gas-liquid absorption using Methyl-Di-Ethanol-Amine, reactive gas-solid adsorption using calcium looping (CaL) technology and membrane separation. For the LCA study, a "cradle-to-gate" approach is carried out using GaBi software, according to the ReCiPe impact assessment method. The general conclusion is that integrating the CCS methods into the cement production process leads to a decrease in global warming potential (GWP) in the range of 69.91%-76.74%. Of the CCS technologies analysed, CaL technically outperforms the others as it requires 34% less coal and provides 1.6 times higher gross energy efficiency. From an environmental perspective, CaL integration ranks first, with the lowest scores in six of the nine impact categories and a GWP reduction of 76.74% compared to the baseline scenario without CCS.