Process integration, energy and exergy analyses of a novel integrated system for cogeneration of liquid ammonia and power using liquefied natural gas regasification, CO2 capture unit and solar dish collectors

Abstract One of the most common methods of ammonia production used in the last hundred years is the Haber-Bosch process. The basis of this process is hydrogen and nitrogen, which must be supplied in different ways. In the present study, a novel integrated structure for tri-generation of liquid ammonia, carbon dioxide, and power through the Haber-Bosch process, amine-based carbon dioxide capture cycle, and absorption-compression refrigeration cycle is developed. The required nitrogen of this process is supplied by the cryogenic air separation system with the help of the liquefied natural gas regasification process and the required hydrogen is supplied through a steam methane reforming process with the help of an amine-based CO2 capture cycle. The needed cooling by the Haber-Bosch process at − 50 °C is also provided by the absorption-compression refrigeration cycle. The required power of the whole system is generated through the organic Rankine cycle. Solar energy heat source and power plant exhaust flue gas are used to supply heat to different parts of the integrated system. Simultaneous design of units and integration of processes reduces the number of required equipment and reduces energy consumption, thus increases the system efficiency. This hybrid structure produces 3.042 kg/s ammonia as the main product, 13,300 kW power, 2.762 kg/s CO2, 3.929 kg/s pure oxygen, and 11.31 kg/s hot water as byproducts. The total energy and exergy efficiencies of the combined structure are 46.95% and 57.36%, respectively. Exergy investigation of the combined system illustrates that the highest rate of exergy destruction includes heat exchangers (46.18%), collectors (18.45%), and towers (14.97%) of the total exergy destruction. Sensitivity analysis is performed on the sensitive parameters of the system and its results are reported.