COMPARATIVE ANALYSIS OF HYDROGEN FIRED TWO SHAFT INDUSTRIAL GAS TURBINE WITH DIESEL FUEL

Abstract

Gas turbine (GT) has played a key role in modern power systems, but rising energy & environmental concerns, moving towards green energy sources, is a need of an hour. Hydrogen, with its high energy density and renewable compatibility, offers a carbon free alternative to reduce greenhouse gases (GHGs) emissions and other pollutants. The research gap lies in the limited investigation of hydrogen fired two-shaft industrial gas turbine, especially emission trade-offs and control strategies for stable operation. This study investigates the performance of a hydrogen fired two-shaft industrial gas turbine in comparison with conventional hydrocarbon fuels. The analysis was carried out using GASTRUB 14, a validated thermodynamics simulation tool, to evaluate parameters such as thermal efficiency, specific fuel consumption (SFC), heat rate and carbon emissions. In addition, a control schedule optimization was performed to ensure stable operation under hydrogen combustion, addressing the challenges of altered flame speed, reduced density and higher diffusivity compared to natural gas. This study examines the influence of inlet-air temperature (233.15-313.15 K) on the performance of a gas-turbine system operating on diesel and hydrogen fuels. Quantitative analysis revealed that increasing inlet temperature caused a substantial loss in turbine power output for both fuels. However, diesel experienced a sharper performance drop than hydrogen. Shaft power decreased from 26,580.76 kW at 233.15 K to 9,972.80 kW at 313.15 K for diesel, whereas hydrogen maintained comparatively higher power 27,299.36 kW to 10,383.61 kW levels due to its higher combustion characteristic. HPT power from 22,572.14 kW to 12,608.14 kW for diesel, whereas hydrogen again retained higher turbine work of 22,799.32 kW to 12,808.43 kW across the range. Thermal efficiency dropped from 0.35 to 0.27 for diesel, whereas hydrogen remained consistently 0.36 to 0.28 more efficient at every inlet temperature. While heat rate increased from 10,230.52 to 13,082.20 kJ/kWh for diesel, in contrast hydrogen exhibited a lower heat rate of 9948.13 kJ/kWh to 12,876.77 kJ/kWh. Accompanied by rise in specific fuel consumption from 0.239 to 0.306 kg/(kW·h) for diesel. Whereas hydrogen due its higher calorific value and higher mixing, requires less mass of fuel for equivalent 0.084001 kg/kWh to 0.10873 kg/kWh. Rotor inlet temperature dropped from 1104.87 K to 1033.70 K and the NOx severity index from 0.23 to 0.20 for hydrogen. Diesel showing lower NOx 0.24 to 0.21 due to higher flame temperatures and rotor inlet temperature increased from 1138.197 K to 1058.23 K. Hydrogen shows exhaust temperatures, rising from 594.59 K to 626.53 K compared to diesel’s 616.25 K to 641.92 K indicating cooler combustion. Its isentropic power turbine efficiency is also slightly higher 0.922 to 0.926 than diesel 0.9216 to 0.9264. The overall pressure ratio (P3/P2) remains lower for hydrogen 15. 94 to 9.17 than diesel 16.15 to 9.35 reflecting reduced compressor-turbine pressure loading.  Across all temperatures, hydrogen maintained higher thermal efficiency than diesel. Results show that elevated inlet temperature severely degrades turbine performance, whereas hydrogen consistently offers superior efficiency characteristics. The optimized control schedule demonstrated improved stability and efficiency across varying load conditions, suggesting hydrogen can be viable transition fuel for industrial turbines when paired with appropriate control strategies.