Micro gas turbine test facility

We have installed an Ansaldo Energia AE-T100 micro gas turbine (mGT) of that produces 100 kW as electrical power. It is usually used for power and heating in residential buildings, hospitals, schools, etc. Several devices are needed to operate the AE-T100 micro gas turbine, as shown in Fig. 1. For ammonia (NH3) fuel delivery, an NH3 plant and evaporator have been commissioned. The NH3 plant (Fig. 2, left) comprises four NH3 drums (Fig. 2, right), each one containing 500 kg of NH3 at 10 bar absolute, and several instruments to allow controlled, continuous operation. The liquid NH3 enters the evaporator (Fig. 3, left), where it is heated up to 60 °C, leaving in gaseous state. A mixing panel (Fig. 3, right) has been installed next to the mGT to mix NH3/CH4/H2/N2 gases prior to combustion, depending on the desired mixture. The NH3 fuel flow rate is controlled with an MFC, and it is mixed prior to combustion with the other gases coming from the mixing panel. A Testo 350 and Horiba V5000 are installed besides the mGT to measure the concentration diverse contaminants in the exhaust gases.

The Ansaldo Energia AE-T100 is a compact and low maintenance single shaft micro gas turbine designed for natural gas operation, typically used in industrial and civil applications. Figure 5 shows the micro gas turbine's layout. It produces 100 kW of electrical power with a rated thermal efficiency of 30%. Its working principle is as follows: the filtered air is compressed in the singlestage centrifugal compressor up to 5 bar absolute at full load operation and guided to the recuperator, where it is preheated up to 500°C by the exhaust gases. The preheated air is distributed into the single-can combustor, where fuel is injected and burned in an overall lean condition at a pressure of 4.5 bar absolute. The high-temperature gases expand through the single-stage centripetal turbine and transfer heat to the recuperator before leaving the turbine.

To protect the mGT since it is an expensive device, a reduced-scale burner (Fig. 6) has been designed and manufactured inspired by the one fitted the AE-T100. This lab-scale solution is intended to test the feasibility of the micro gas turbine running on novel fuels such as NH3. It consists of a pilot combustion chamber, where the fuel and air are injected separately in the center to create a non-premixed swirl flame; a main swirl mixing chamber where the main fuel and air mix prior to combustion; and a secondary air swirler that provides flashback protection and enhances fuel-air mixing inside the combustion chamber. The extra feature of this burner is the ability to independently vary the proportions of air supplied to the three different air inlet ports (pilot, main, and secondary) and the proportion of the fuel supplied to the two fuel inlets.