Comparative study of seven agricultural wastes for renewable heat and power generation using integrated gasification combined cycle based on energy and exergy analyses

The main objective of this study was to generate renewable energies (i.e., thermal energy and electricity) by turning agricultural waste to green energy based on waste gasification integrated with low-temperature air separation, gas turbine, and CO2 power generation cycle. Furthermore, cold energy recovery of liquefied natural gas was performed to reduce energy consumption. Today, energy recovery from renewable resources, such as agricultural waste, is a perfect opportunity to provide valuable products efficiently. Accordingly, rice husk, rice straw, wheat straw, milled straw, milled grain waste, cotton gin waste, and block wood were used in the proposed process. The used air separation unit provided high purity oxygen (99.98%) for gasification and nitrogen (99.99%) as a byproduct. The results showed that the specific energy consumption of ASU decreased up to 0.07 kWh per unit-kilogram of produced pure oxygen and nitrogen compared to the conventional unit. Also, the thermal efficiency of the power generation cycle was about 45%. Milled straw and rice husk had the highest cold gas efficiency (88.41%) and carbon conversion efficiency (97.64%) in the gasification process, respectively. The results indicated that rice husk gasification could generate the most electric power (8,328 kW) and milled straw could provide the most flow rate of hot water at 85 degrees C (129,240 kg/h) as thermal energy.