Thermodynamic analyses of a biomass integrated fired combined cycle

• Published in: Applied thermal engineering 2013-09, Vol.59 (1-2), p.60-68
• Main Authors: Soltani, S., Mahmoudi, S.M.S., Yari, M., Rosen, M.A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Biomass; Biomass gasification; Combined cycle; Combined cycle engines; Energy; Energy management; Energy. Thermal use of fuels; Exact sciences and technology; Exergy; Gas turbines; Heat transfer; Inlet temperature; Natural energy; Natural gas; Post combustion; Power generation; Pressure ratio; Theoretical studies. Data and constants. Metering
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2013.05.018

A biomass integrated fired combined cycle (BIFCC) is proposed and examined with energy and exergy analyses. A focal point is the biomass gasification process, for which four different biomasses are examined. The fuel in the bottoming cycle is a biomass while the topping cycle fuel is natural gas. The analyses consider a range of compressor pressure ratios (6–24), gas turbine inlet temperatures (1300–1500 K), heat recovery steam generator (HRSG) inlet temperatures (840–940 K) and molar natural gas to biomass ratios (0.05–1.50). The energy efficiency is compared when the cycle uses natural gas, or natural gas and biomass (of various kinds). The efficiency is seen to be maximized at an optimum pressure ratio, which depends on the gas turbine and HRSG inlet temperatures. Increasing the gas turbine and decreasing the HRSG inlet temperatures leads to in an increase in energy and exergy efficiencies for the cycle. The performance of an 80-MW capacity plant is investigated for three cases, with optimum pressure ratios and various operating parameters. The most advantageous performance among the three cases, for which the energy and exergy efficiencies are 53.16 and 48.39% respectively, is achieved when the turbine inlet temperature is 1500 K, the HRSG inlet temperature is 840 K and the compressor pressure ratio is 14. •A gas turbine combined cycle with gasified biomass firing is analyzed.•Thermodynamic analysis considers first and second law analyses.•Thermal efficiency peaks at an optimum cycle pressure ratio (about 10–14).•Three sets of operating parameters are considered in a detailed case study.•One of three cases is more efficient from energy and exergy viewpoints.