Circular bioenergy pathway for sustainable hydrogen production with carbon capture: Technical, economic & environmental assessment

The accelerating global demand for hydrogen is pushing for renewable and waste derived hydrogen production processes, where, date palm waste (DPW) has been identified as an available and unexploited agricultural residue that has the potential to be a sustainable source of hydrogen. The current work focuses on developing and evaluating four different process configurations in terms of energy, environment and economics for producing hydrogen from DPW using Aspen Plus® simulation tool. Case 1 represents the standalone DPW gasification with CO₂ capture via methanol absorption, Case 2 represents the DPW gasification with CaO-based chemical looping for CO₂ capture, Case 3 represents the DPW gasification integrated with steam methane reforming (SMR) and methanol-based CO₂ capture, and Case 4 represents the DPW gasification integrated with SMR and CaO-based CO₂ capture. Each case was evaluated in terms of syngas composition, hydrogen production, lower heating value, CO₂ captured, utility demand, process efficiency, and H₂ production cost. Hydrogen production ranged from 974.55 t/year (Case 1) and 988.83 t/year (Case 2) to 2032.32 t/year (Case 3) and 2048.61 t/year (Case 4). CO₂ capture was also more effective in Case 4 (16,929.49 t/year) compared to Case 1 (7676.30 t/year). Process efficiency improved from 33 % in Case 1 to 47 % in Case 2, and from 32 % in Case 3 to further to 55 % in Case 4. Economically, Case 1 offered the highest hydrogen production cost ($5.03/kg) followed by Case 2 ($4.77/kg), while Case 3 and Case 4 achieved significantly lower production costs of $2.89/kg and $2.69/kg, respectively.