Comprehensive technical study of a novel polygeneration arrangement using natural gas power plant and geothermal energy for producing electricity, heat, fresh water, and methanol

• Published in: Process safety and environmental protection 2023-12, Vol.180, p.98-121
• Main Authors: pulla, Bhanu pratap, Nutakki, Tirumala Uday Kumar, Albani, Aliashim, Agrawal, Manoj Kumar, Begum, M.Yasmin, Han, Wenju
• Format: Article
• Language: English
• Subjects: Aspen HYSYS; Economic analysis; Geothermal power plant; Low CO2 emission; Methanol synthesis; Polygeneration arrangement
• ISSN: 0957-5820; 1744-3598
• DOI: 10.1016/j.psep.2023.10.001

Structural modifications play a crucial role in enhancing the sustainability of natural gas power plants owing to their significant contribution to greenhouse gas emissions and irreversibility factors. One primary solution is using waste heat recovery systems integrated with these power plants, producing different products. Furthermore, integrating renewable energy resources into the entire system within a co-feed framework may be a viable method for further enhancements. The current study focuses on a novel heat integration process combined with a natural gas power plant, which uses geothermal energy as an auxiliary energy source. The newly designed system encompasses a gas turbine cycle, two modified geothermal power plants, a water electrolyzer unit, and a methanol synthesis unit. The process is simulated utilizing the Aspen HYSYS software, and to evaluate its viability, analyses are performed pertaining to energy, exergy, environment, and economics. Furthermore, a comprehensive parametric analysis is conducted on the primary performance indicators. The simulation results show that the process’s energy, exergy, and electrical efficiencies equal 53.85%, 47.30%, and 40.26%, respectively. The environmental evaluation demonstrates that the specific carbon dioxide emissions associated with the total energy produced and the sum of power and heating are 0.27 kg/kWh and 0.294 kg/kWh, respectively. From the economic aspect, the total unit cost of the products and the cost of energy of the system are 20.69 $/GJ and 0.086 $/kWh, respectively. Also, total annual cost, investment cost, and net present value of 222.81 M$, 1010.64 M$, and 1220.57 M$, respectively. •Proposal of a novel polygeneration system using natural gas and geothermal energy.•Producing electricity, hot water, fresh water, and methanol simultaneously.•Use of Aspen HYSYS for simulation and multi-aspect study from 4E perspective.•Total exergy efficiency and total unit cost of the product are 47.3% and 20.69 /GJ.•The CO2 emission based on the total energy produced equals 0.27 kgCO2/kWh.