HOW IT WORKS
Finno Exergy’s patented Pressure Gain Combustion (PGC) technology introduces a breakthrough in gas turbine efficiency. Unlike conventional combustors that lose pressure, Finno Exergy PGC system increases the pressure during combustion, allowing more energy to be harnessed by the turbine. This means superior thermodynamic performance.
The core of the system is a combustor that operates on fast deflagration. Inlet valve timing and the specifically designed combustor shape generate a self-sustaining swirl and tumble flow pattern. This ensures rapid and complete combustion, while the combustor outlet remains open to the turbine. The result is a net pressure gain across the combustor, which translates directly into improved efficiency as well as reduced fuel consumption and emissions.
SUPERIOR EFFICIENCY
Gas turbines have evolved decades mainly through the optimization of compressor and turbine. These systems are already reaching the limits of their efficiencies causing further developments less and less cost effective. At the same time, the major loss of useful energy takes place in the combustor with no significant improvement in sight due to the inherent inefficiencies of Brayton cycle – in which the operation of every gas turbine is based on. This is to be changed by the Finno Exergy PGC which drastically improves the thermodynamic cycle of gas turbine operation offering immediate and cost-effective improvement to the efficiency.
Finno Exergy PGC technology consistently delivers pressure gains between 20–30%, depending on fuel blend and turbine configuration. These gains translate into substantial thermal efficiency improvements. Simulations performed by Finno Exergy in co-operation with a gas turbine OEM show 15% efficiency increase in a 10 MW scale industrial gas turbine engine. This means more than 2 500 000 EUR of annual fuel savings.
FLEXIBLE FUEL OPTION
PGC combustor test rigs developed by Finno Exergy were tested with a various fuels, both liquid and gaseous. The second-generation test rig was specifically designed to operate with any blend of hydrogen and methane, and it delivered consistent performance across all tested mixtures. Fuel switching is handled seamlessly via the control system, allowing users to adapt to fuel availability or regulatory requirements with a simple software adjustment.
Finno Exergy is among the first to achieve full fuel flexibility, including operation with pure hydrogen, which presents unique challenges due to early ignition risks. The system’s adaptability makes it ideal for future energy landscapes where hydrogen will play a central role.
MINIMAL EMISSIONS
Efficiency increase presented by FinnoExergy PGC technology not only brings savings in fuel costs, but it also cuts CO2 emissions by respective amount. This allows operators to save from ever increasing emissions fees.
Flexible fuel option gives the operator a possibility to burn hydrogen or biofuels instead of or together with conventional fuel bringing up a possibility to cut the CO2 emissions even more.
NOx emissions were measured to be less than 20 ppm normalized to 15% O2 levels during the tests conducted with the second-generation test rig.
RETROFIT POTENTIAL
Finno Exergy PGC technology is specifically designed for retrofitting existing gas turbines, offering a cost-effective path to decarbonization and efficiency improvement. The combustor integrates with standard turbine architectures requiring minimal modifications.
By replacing the conventional combustor with Finno Exergy PGC unit, operators can achieve higher efficiency, lower emissions, and improved fuel flexibility without the need for full system replacement. This makes the technology particularly attractive for industrial and utility-scale applications where capital investment and downtime are critical considerations.
EXPERIMENT AND SIMULATION
To validate and optimize the PGC technology, Finno Exergy has developed two generations of test rigs.
The first test rig was a closed-loop system consisting two stages of intercooled radial compressors and corresponding two stages of radial turbines in a twin shaft arrangement. It demonstrated a 27.9% pressure gain with a variety of liquid fuels and confirmed the viability of the fast deflagration approach. Results acquired with this first-generation test rig earned FinnoExergy a win in the New Energy Challenge competition hosted by Shell and provided a baseline for further development.
The second-generation test rig, developed under the Shell Gamechanger program, is an open-loop system designed for gaseous fuels and enhanced control. It includes a new combustor block, fuel system, and control electronics with safety features as well as an adjustable choke and a heat exchanger to simulate turbine conditions. The rig successfully operated with hydrogen-methane blends achieving up to 40% pressure gain and demonstrated industry standard NOx emissions.
Simulation plays a key role in Finno Exergy’s development strategy. During the early development of the PGC system, 1D parametric models of the system were coupled with 3D CFD flow simulation. Coupling 1D and 3D simulations is common in engine development but due to the unusual characteristics of the Finno Exergy combustor, it was initially unclear whether this could be done. However, the agreement between simulated and measured results was found excellent. The coupled simulations backed by test results were essential for accurate prediction of heat release during combustion.
In the later stages of development, 1D parametric models are used to scale performance predictions, while 3D CFD simulations optimize flow dynamics, combustion timing, and heat transfer. These models are validated against experimental data and are essential for designing retrofit solutions for industrial turbines.
