Recently, there has been a great interest in developing zero-emission energy systems. Several attempts have been made to develop such systems based on biomass gasification. However, previous studies have not dealt with developing zero-emission systems based on co-gasification of plastic/biomass using capturing CO2 and its utilization to produce power and fuels. The present study aimed to develop a novel zero-emission system to produce power, methane and ammonia using capturing and utilization of CO2 in a Graz cycle. This novel system was triggered using steam co-gasification of polyethylene and chickpea straw and methane and ammonia were produced in a Sabatier reactor and an ammonia production unit, respectively. Key variable parameters and significant simultaneous influences were recognized using analysis of variance. Four-objective optimization and machine learning analysis were utilized to identify the optimum system performance and to develop models to predict the outputs, respectively. System efficiency of 39.54%, output power of 682.20 kW, methane production of 22.68 g/s and ammonia production of 97.35 g/s were the optimum system performance. Machine learning analysis efficiently developed models with R2 values more than 95%. The research results represent a further step towards developing zero-emission system based on capturing and utilization of CO2.
