Experience From Burning Highly Aromatic Fuels in GT35, 17 MW, Gas Turbine

Abstract

The aromatic hydrocarbon content in a gas turbine fuel has a great influence during combustion. The aromatic hydrocarbon content governs the hydrogen content and has an indirect effect on fuel burning characteristics like the luminometer No and the smoke point. ABB Stal got an oportunity to sell a standard GT35 gasturbine set for electrical generation to a refinery in Thailand, provided the customers prefered fuel, a naphtha containing up to 75 vol% aromatics, could be used. A theoretical “state of the art” study indicated that 75 vol% aromatics certainly was in the unexperienced area. Most gas turbine fuel specifications set an upper limit for the aromatic content at 30–35% for industrial GT and at 20–25% for aero engines. Higher values could result in smoke formation during combustion. This paper describes a full scale test with the ABB GT35 standard industrial gas generator operating on a liquid fuel containing up to 75% aromatic hydrocarbon content. The measurements of CO, UHC, NOx and the smoke number, in Bacharach, taken from the exhaust during the test, will be presented as well as the influence of the combustion on the combustor wall temperature. The effect of the unique standard design on the GT35 air and fuel mixing of the primary combustor section (patented 1965) will be discussed to show how a very complete combustion was obtained also with a 75% aromatic content in the fuel. After the test that showed that GT35 was able to burn 75% aromatics whitout smoke formation - the set was sold and delivered.