The gas turbine system is comprised of two Turbec T100 PH microturbines: a Series 1 and a Series 3.
Both turbines are combined heat and power (CHP) units integrating the T100 power module with a recuperator and exhaust gas heat exchanger for thermal energy recovery to improve efficiencies.
The Turbec T100 CHP units are typically fuelled by natural gas, but the use of fuels such as biogas, syngas, diesel, kerosene, methanol and LPG is also possible.
The microturbines use a high-speed generator to produce electricity, exported to the grid via our substation, with the single-stage centrifugal compressor and the radial turbine both placed on the same shaft as the generator. An exhaust gas recuperator is connected to the microturbine to improve electrical efficiency and the hot flue gases are expelled through a water-gas heat exchanger to generate thermal energy.
The turbine consumes 330 kW of natural gas and generates a maximum of 100 kW of electrical power at an efficiency of 33%. Used in combination with the counter-flow heat exchanger, each unit can generate an additional 165 kW of thermal power, bringing the overall efficiency to almost 80%.
The flue gases from the heat exchanger is connected to the central exhaust line, which is integrated with the post-combustion, solvent-based carbon capture plant. This enables research into various aspects of post-combustion capture from gas turbine-based power generation. These systems are highly instrumented to allow for full characterisation.
The concentration of CO2 in flue gases from gas turbines is typically very low, which impacts on the economical and technical viability of the carbon capture process.
PACT has deployed a range of modifications to the turbines to improve system efficiency and enhance capture performance. These include exhaust gas recycling (EGR), selective exhaust gas recirculation (S-EGR) and humidification of the gas turbine cycle.
- Exhaust gas recycle (EGR) is an established concept for increasing the CO2 concentration in the flue gas, as well as minimising emissions of NOx. A portion of exhaust gas is recycled back into the air inlet, replacing nitrogen in the air and creating a CO2-rich combustion atmosphere and subsequently higher CO2 in the exhaust. Increasing the level of CO2 in the flue gas is important for the economic operation of post-combustion carbon capture technologies that work on a concentration gradient (i.e. solvent-based capture). At PACT we simulate the EGR process via small additions of CO2 to the combustion air.