(424d) Estimation of Energy Potential for Biogas Produced from Municipal Solid Waste (MSW) in Landfill of Astana Using Aspen Plus

This study provides an estimation of energy potential for biogas produced from municipal solid waste (MSW) in landfill of Astana. The energy conversion was evaluated in the form of electricity as well as economic assessment of the proposed power plant design. The developed energy model was simulated by a process modeling tool (ASPEN Plus). The input parameters such as volumetric flow rate of biogas, biogas composition and morphological fraction of the MSW were provided by the municipality of Astana city council. For the biogas composition, the measurements were conducted by a mobile gas analyzer during summer 2016. However, small corrosive concentration in biogas such as H₂S and HCl were assumed in the model from the data available in the literature.

As part of the simulation, the reduction of corrosive hydrogen sulfide (H₂S) concentration in the gas was simulated in this model by a water scrubbing system. Further, obtaining a maximum rate of power production, the upgraded biogas was utilized in a combined cycle gas turbine (CCGT) unit. This configuration was done by adding the Rankine cycle to the Brayton cycle to build up the combined system. As a result, the efficiency of the system has increased from 35% to 49%, with power output of 5 MWh. After obtaining the results of the energy model, the economic viability of the project was evaluated. The analyses showed that with right investment, the project can be highly profitable. With equity payback period of 2 years, the NPV of the project was close to 20 mln USD, and annual life cycle savings around 3.2 mln USD.