Gas plants are one of the main obstacles to the energy transition towards production methods free of harmful emissions. For example, El Español highlighted, it still represents around 20% of Spain's energy mix, although there are countries where this proportion is several times higher. Italy is a good example of this, as more than 40% of its electricity needs come from gas, a number that Italy intends to reduce in the coming years by investing in hydrogen.
The European Union, through the “Flexibility for Hydrogen” (FLEX4H2) project, intends to promote this type of technology in cooperation with Switzerland. “The goal is to develop a flexible combustion system capable of operating with any concentration of hydrogen in natural gas, up to 100% hydrogen.”
This has already been achieved.
Within the scope of the programme, Ansaldo Energia showed that a modified chamber version of its GT36 turbine can operate on fuel made of 100% hydrogen. “Sequential combustion technology achieves operating flexibility from 0 to 100% hydrogen in high-pressure tests,” they explained in a statement.
Tests of this new technology were carried out in Germany, one of the most important hydrogen centers in the European Union, and “highlighted the ability of the combustion chamber to convert perfectly between natural gas and hydrogen,” said Ansaldo Energia, “demonstrating its outstanding operational and fuel flexibility.” .
According to the company, “innovative sequential combustion technology allows the GT36 to operate with a wide range of hydrogen and natural gas mixtures,” thus ensuring “its ability to adapt to the ever-evolving needs of current and future gas production markets.”
This achievement represents a “fundamental technological breakthrough for large gas turbines,” especially those intended for large-scale electricity generation. “Decarbonisation of gas turbines is an essential part of the transition in the energy scenario,” explained Federico Bonzani, Product and Technology Director at Ansaldo Energia.
It also increases the generating capacities and environmental potential of this type of turbine when put into service in power plants. “A single engine equipped with the new FLEX4H2 combustion system has the potential to remove up to 2 million tons of carbon dioxide per year.”
At the same time, it “provides enough clean energy to power up to 500,000 homes”: in other words, so that we can compare, there are 5.97 million classic single-family homes in Portugal – which include homes of regular residence, seasonal use and vacant homes – in Porto. In the largest, there are just over 600,000 homes, and in Alentejo, 466,000. In other words, just over 10 ships arrived to supply Portugal.
The technology behind this new industrial advance is based on sequential combustion, which uses two systems. The first is aerodynamic flame stabilization and the second is self-ignition stabilization. “It provides exceptional performance in terms of NOx and carbon monoxide emissions.”
It is not an easy process: changes in fuel composition present a major challenge for turbine design – because the flame changes its characteristics and position in different stages of combustion. For example, the flame may subside and the auto-ignition duration may be reduced, impairing the ultimate performance of electricity generation.
The adaptation of the turbine carried out by the company “Ansaldo Energia” makes it possible to compensate this entire process with infinite proportions between gas and hydrogen. This is done by adjusting the equivalence ratios and amounts of fuel that are injected into the various stages of the device.
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