Urea, a key derivative of ammonia, is widely used in agriculture and has a significant impact on food security. This study evaluates a sustainable urea production pathway that utilizes hydrogen generated from water electrolysis for green ammonia synthesis and CO₂ captured from a cement plant using an MEA-based process. This study employed Aspen Plus V12.1 and MATLAB to develop rigorous system-level models of all subsystems involved in the sustainable urea production process. These subsystems include a cryogenic air separation unit (CASU), a modular system of alkaline electrolysers (AEL), a green Haber-Bosch (HB) process, an MEA-based CO₂ capture system, and the Stamicarbon process. To enhance the energy efficiency and cost-effectiveness of urea production, waste heat generated during green ammonia synthesis in the HB process was integrated into the stripper column of the MEA-based CO₂ capture system for solvent regeneration. A detailed economic analysis was conducted to assess the impact of this heat integration (HI) on reducing the CO₂ capture costs and, consequently, the overall urea production costs. Additionally, several heat supply scenarios were evaluated to meet the heat demand of the CO₂ stripper column in the Stamicarbon process. These included natural gas combustion, a cascade heat pump (HP), and natural gas combustion integrated with a cryogenic CO₂ capture (CCC) system. The results indicated that HI significantly decreases both the energy penalty and costs of the MEA-based CO₂ capture process, reducing the CO₂ capture costs by 41.27 % in 2024 and lowering the energy penalty by 50.40 %. Among the scenarios investigated, the cascade HP with HI proved to be the most cost-effective option for urea production. Additionally, electricity costs for operating the modular alkaline electrolyzers (AEL) dominate the sustainable urea production expenses, with 88.07 %–91.26 % of electricity costs allocated to AEL, depending on the selected production scenario. The modular AEL also represents the largest share of initial investment costs, accounting for 90.62 % of total capital expenditures in the urea production process.

Many governments around the world have taken action to utilise carbon capture (CC) technologies to reduce CO2 emissions. This technology is particularly important to reduce unavoidable emissions from industries like cement plants, oil refineries, etc. The available literature in the public domain explores this theme from two distinct perspectives. The first category of papers focuses only on modelling the CC plants by investigating the details of the processes to separate CO2 from other gas components without considering the industrial applications and synergies between sectors. On the other hand, the second category investigates the required infrastructure that must be put in place to allow a suitable integration without considering the specific particularities of each carbon capture technology. This review gives a comprehensive guideline for the implementation of CC technologies for any given application while also considering the coupling between different energy sectors such as heating, power generation, etc. It also identifies the research gaps within this field, based on the existing literature. Moreover, it delves into various aspects and characteristics of these technologies, while comparing their energy penalties with the minimum work required for CO2 separation. Additionally, this review investigates the main industrial sectors with CC potential, the necessary transportation infrastructure from the point sources to the end users, and the needs and characteristics of storage facilities, as well as the utilisation of CO2 as a feedstock. Finally, an overview of the computation tools for CC processes and guidelines for their utilisation is given. The guidelines presented in this paper are the first attempt to provide a comprehensive overview of the technologies, and their requirements, needed to achieve the cross-sector coupling of CC plants for a wide range of applications. It is strongly believed that these guidelines will benefit all stakeholders in the value chain while enabling an accelerated deployment of these technologies.