Combustion Improvement Additives For Gas Turbine Liquid Fuels
Most particulates emitted at gas turbine exhaust stacks are generated during the combustion process and essentially result from incomplete burning of the hydrocarbon fuel. Minor contributions may also result from suspended solids in the fuel oil, particles ingested through the compressor air inlet filtration system, and other sources such as scale or ash in the engine and exhaust stack etc. Also, depending on dew point temperature conditions, water and SO3 formed during the combustion process may condense as sulphuric acid droplets and further increase the total amount of particulate measured.
Incomplete combustion in gas turbines is primarily associated with the chemical properties of the liquid hydrocarbon fuel, and certain types of fuel are more susceptible than others. For example, heavy residual-grade fuel oils with high asphaltene content and paraffinic fuel oils containing long-chain wax molecules are likely to emit unburned carbon-rich particles. Aromatic fuel oils with long carbon chains are also well known for creating soot (unburned hydrocarbon) in diffusion flames. However, the tendency for a given fuel to generate smoke and particulate emissions is also influenced by several other factors such as - high fuel viscosity, high flame ignition temperature, high fuel carbon to hydrogen ratio, the efficiency of fuel atomization at the burners, and the residence time available for complete oxidation within the combustion zone.
Smoke formation resulting from insufficient combustion air is a very common problem in conventional steam boilers, because air to fuel ratios are deliberately minimized. This is unlikely to affect gas turbine combustion due to the prevailing high excess air conditions, but it can be a contributing factor under certain low load situations.
Turbotect provides a range of additives that are specially formulated to improve the combustion characteristics of gas turbine liquid fuels, thereby reducing the tendency of the fuel to create unburned hydrocarbon particulates and smoke. The active metal content of these additives functions as a combustion catalyst to promote complete oxidation of long-chain hydrocarbon molecules and heavy heterocyclic components such as asphaltenes.
TURBOTECT ER-18 is an iron-based catalyst that improves combustion efficiency by promoting the complete oxidation of heavy hydrocarbon components and carbon particles, thereby reducing soot and visible smoke emissions.
TURBOTECT 703 is a combination fuel additive containing iron and magnesium. The product is specially designed to inhibit high temperature vanadic corrosion of gas turbine blades and vanes, and also functions as a combustion catalyst to reduce particulate emissions.