Experimental Investigation of Fuel Composition Effects on Syngas Combustion

Abstract

The OPRA OP16 gas turbine is an all radial single-shaft gas turbine rated at 1.9 MW with a successful track record from oil and gas applications as well as industrial and commercial CHP applications. To meet the growing demand for alternative fuels, OPRA Turbines has developed a new tubular combustor for the OP16 gas turbine fleet. The combustor has been successfully tested on a wide variety of (ultra-) low-calorific gaseous fuels in an atmospheric combustion test rig. This paper presents an experimental investigation of syngas combustion in the low-calorific fuel combustor. The effect of the variation in fuel composition on the combustion characteristics has been investigated extensively. This includes the effect of variable heating values and variations in the ratio between hydrogen and carbon monoxide and between syngas and hydrocarbons. The effects of these variations on the combustor performance, emissions and lean blowout limits will be discussed and compared to the results obtained from the combustion of propane. Major differences in emissions have been found, mainly influenced by the flame temperature and presence of hydrogen in the fuel. Lean blowout of the combustor is largely determined by the presence of hydrogen, whereas other components are found to have less influence. Theoretical calculation, based on le Chatelier’s rule and a method based on heat release, of the lean blowout limit has been compared to the experiments. It was found that the heat release method predicts the flammability limit more accurately than le Chatelier’s rule. This is caused by the inaccuracy of the latter to handle fuels with a large amount of hydrogen.