An Advanced Design to Generate Power and Hydrogen with CO2 Capturing and Storage for Cleaner Applications

The present study aims to conduct a thermodynamic analysis of a novel concept that synergistically integrates clean hydrogen and power production with a liquified natural gas (LNG) regasification system. The designed integrated energy system aims to achieve hydrogen production, power production, liquified natural gas regasification, carbon capture storage, and in situ recirculation. Hydrogen sulfide (H2S) from industrial waste streams is used as a major feedstock and filtration combustion of H2S is employed as a hydrogen production method. CO2 obtained from the combustion process is liquified and pumped at a high pressure to recirculated back to the CO2 cycle power generation combustion process. The flu gas obtained after expansion on the turbine is condensed and CO2 is captured and pressurized. The entire plant is simulated in the Aspen Plus simulation environment and a comprehensive thermodynamic assessment including the energy and exergy analysis is conducted. Additionally, several parametric studies and assessments of various factors influencing the system's performance are conducted. From the sensitivity analyses, it is found that at 20% CO2 recirculation, the hydrogen production rate decreases by 31.81% when the operating pressure is increased from 0.05 bar to 3 bar. The adiabatic temperature is reduced by 39.72%, 35.37%, and 32.85%, when 50%, 60%, and 70% CO2 is recirculated in the oxidant stream at an oxygen to natural gas (ONG) ratio of 0.5. The energy and exergy efficiencies of the system are found to be 71.48% and 60.69% respectively. The present system avoids 2571.94 tons/yr of CO2 emissions for clean hydrogen production and 1426.27 tons/yr of CO2 for clean power production which would otherwise be emitted from steam methane reforming and coal gasification.