Co-Firing of Hydrogen and Natural Gases in Lean Premixed Conventional and Reheat Burners (Alstom GT26)

Abstract

Addition of hydrogen (H2), produced from excess renewable electricity, to natural gas has become a new fuel type of interest for gas turbines. The addition of hydrogen extends the existing requirements to widen the fuel flexibility of gas turbine combustion systems to accommodate natural gases of varying content of higher hydrocarbons (C2+). The present paper examines the performance of the EV and SEV burners used in the sequential combustion system of Alstom’s reheat engines, which are fired with natural gas containing varying amounts of hydrogen and higher hydrocarbons. The performance is evaluated by means of single burner high pressure testing at full scale and at engine-relevant conditions. The fuel blends studied introduce variations in Wobbe index and reactivity. The latter influences, for example, laminar and turbulent burning velocities, which are significant parameters for conventional lean premixed burners such as the EV, and auto-ignition delay times, which is a significant parameter for reheat burners, such as the SEV. An increase in fuel reactivity can lead to increased NOx emissions, flashback sensitivity and flame dynamics. The impact of the fuel blends and operating parameters, such as flame temperature, on the combustion performance is studied. Results indicate that variation of flame temperature of the first burner is an effective parameter to maintain low NOx emissions as well as offsetting the impact of fuel reactivity on the auto-ignition delay time of the downstream reheat burner. The relative impact of hydrogen and higher hydrocarbons is in agreement with results from simple reactor and 1D flame analyses. The changes in combustion behaviour can be compensated by a slightly extended operation concept of the engine following the guidelines of the existing C2+ operation concept and will lead to a widened, safe operational range of Alstom reheat engines with respect to fuel flexibility without hardware modifications.

Superior fuel and operational flexibility of sequential combustion in Ansaldo Energia gas turbines

“…Adapting the fuel ratio between first stage and second stage for optimum combustion performance was also extensively applied to high hydrocarbons within GT26 fleet (Riccius et al, 2005;Wind et al, 2014).…”

Feasibility analysis of flameless combustion in high-parameter gas turbine combustor

“…(3 图 5 类型III典型结构示意图. (a) SPRF燃烧器 [29] ; (b) 亚琛大学 [30] ; (c) 里斯本理工方案2 36~41] ; (b) 荷兰Delft大学 [42] (c) 马里兰大学2 [43] (D: 分混合, 实现了无焰燃烧过程和更低的NO x 排放 [49,50] . Figure 11 Trapped-vortex flameless combustor [52].…”

The Influence of Carrier Air Preheating on Autoignition of Inline-Injected Hydrogen–Nitrogen Mixtures in Vitiated Air of High Temperature

“…The mass flow rate of carrier air was calculated with a fixed set point carrier-to-fuel mass flow ratio (CFR) of 1.0 for all measurement points. The carrier air was preheated to temperatures of 303 K, 523 K, 573 K, 623 K and 703 K in order to mimic real gas turbine conditions [7][8][9]. During the experiments the bulk velocity and the oxygen content were kept constant at 200 m/s and 15 ± 0.5 vol.…”

“…Various investigations of autoignition of hydrogen-nitrogen fuel mixtures at conditions relevant to gas turbine operation, e.g. in reheat combustion systems [7][8][9], have been conducted at DLR Stuttgart and have improved the understanding of the influences of pressure and temperature on autoignition events. The focus of these previous studies of a jet-in-crossflow configuration [10,11] were fuel flexibility and investigations of autoignition kernels formation and their influence on flame stabilisation.…”

“…The present study mimics conditions relevant to gas turbine operation as they may occur e.g. in reheat systems [7][8][9]. Autoignition in the present study is investigated by high-speed luminescence imaging at recording rates of 30 kHz.…”