Achieving absolute sustainability across integrated industrial networks - a case study on the ammonia process

Within the current global climate, precedence has been set on achieving greater sustainable development within process industries. The ammonia process (BAU case) has been labelled as a significant greenhouse gas (GHG) producer-mainly due to high energy demand and CO(2)emissions. This places the process under substantial scrutiny in terms of its climate change impacts and thus, provides a strong case study for viable transition towards greater sustainable operations. Here we examine, for the first time, sustainable eco-park designs for the diversification of the ammonia industry utilizing industrial symbiosis. The network considers several carbon capture and utilization (CCU) applications as well as ammonia (NH3) integration to produce the following downstream products: NH3, urea, Urea Ammonium Nitrate (UAN), Melamine (Mel) and Methanol (MeOH). Our results demonstrate improved energy efficiency with the inclusion of MeOH while UAN decreases net energy demand. Economically, the incorporation of MeOH gave attractive returns on investment due to increased productivity. Insights into environmental sustainability, through the assessment of Planetary Boundaries (PBs), revealed high risk operations aligned to climate change and ocean acidification earth systems linked to BAU operations. These impacts improved considerably with the addition of MeOH, resulting in safe operations of the ammonia process, attributed to increased waste recovery. These results were further supported using Life Cycle Sustainability Assessments, highlighting the potential of the BAU + urea + UAN + Mel + MeOH eco-park design for enhanced sustainable development. Overall, the findings of our paper suggest that upcoming and existing ammonia facilities can exploit industrial symbiosis to achieve greater sustainability through diversification of process operations.