Fueling precision: Density Analysis of Volatile and Easily Evaporating Samples

Introduction

Accurately measuring light and easily evaporated samples, such as gasoline, diesel, and acetone presents a formidable challenge. The susceptibility of these samples to evaporation during the filling procedure and measurement can lead to inaccurate results, hindering the precision required. This application report aims to address this challenge by introducing a solution: utilizing a specially designed accessory that allows for the measurement of volatile samples under pressure. The procedure significantly relieves the risk of errors induced by evaporation, ensuring reliable and reproducible results.

Volatile samples are substances that tend to evaporate easily at normal temperatures and pressures. These samples have a high vapor pressure, resulting in their rapid conversion from liquid to vapor or gas phase. The weaker the intermolecular forces between molecules in a liquid state the more volatile the sample. Volatility is a characteristic also associated with low boiling compounds. [1]

Examples of volatile substances include various samples and solvents such as:

• gasoline,
• diesel,
• acetone,
• and other substances with higher vapor pressure and low boiling points.

Gasoline and diesel, derived from crude oil, find widespread use in internal combustion engines. Crude oil encompasses a diverse array of hydrocarbon compounds, including short-chain alkanes like propane or butane, alkenes, naphthene, and aromatics. With heat distillation of crude oil various petroleum derivatives such as petroleum gases, jet fuel, kerosene, gasoline, diesel, heavy fuels, machine oils, and asphalt can be produced. [1]

Gasoline, being more volatile than diesel oil, or kerosene, owes its characteristics not only to the base constituents but also to additives. Volatility is often regulated by blending with butane, which boils already at -0.5 °C thus creating various difficulties when measuring at higher temperatures. [2]
In industries like petroleum, where various intermediates and final products may exhibit accelerated evaporation, lower boiling points, and consequently pose challenges during sample filling and measuring, the utilization of Pressurized Measurement Units (PMU), an accessory to Xsample 530, proves to be of advantage.