ISO 4261:2013 pdf free

ISO 4261:2013 pdf free.Petroleum products – Fuels
The turbine user should confirm that arrangements are made to ensure that the fuel entering the combustion chambers meets the manufacturer’s requirements. This might include transportation arrangements with the fuel supplier, particular care in fuel storage, quality control at the point of use, and fuel purification procedures. Distillate fuels are usually of satisfactory purity as refined fuels, but suppliers rarely have control over possible trace contamination by metals during distribution and storage. The limits in the present Annex, although recommended for the fuel entering combustion chambers, do not apply to the fuel as delivered unless mutually agreed upon by the interested parties. Fuels may, therefore, require further treatment, quality control procedures, special handling, or other arrangements. The significance of trace metals in respect to hot corrosion of turbine components is discussed in C.4. In the absence of specific guidance from the turbine manufacturer, the present Annex gives guideline limits for trace metals in the fuel entering the combustion chambers. These limits are shown in Table B.1.
Appropriate reference methods for the determination of trace metals are under development. Other methods may be agreed between the user, fuel supplier, and turbine manufacturer for quality control purposes. Adapted methods for the determination of concentrations of sodium, potassium, calcium, and lead are under development. For vanadium, the recommended method is ISO 8691; for sodium, potassium, lead, and calcium, a suitable method is ASTM D 3605[2] or equivalent methods pending the publication of relevant International Standards.
There is a relationship between operating conditions, materials, material life, and the corrosive trace metal content of the fuel. However, although maintenance may be reduced and the life of turbine parts prolonged by exceptionally low levels of metals in fuels, the availability of such fuels may be restricted.
The user may choose to adopt levels different from those of Table B.1 if, after discussion with the turbine manufacturer and the fuel supplier, he determines that his overall operation can thereby be optimized.
In order to minimize high-temperature corrosion, it is important that the melting point of the ash be well above the maximum temperature of materials in the gas passage. Therefore, by agreement between the manufacturer of the turbine and the user, either the melting point or the sticking point can be determined and may be used as an alternative to the limits given in Table B.1. This point is discussed further in C.4.ISO 4261 pdf download.