ANALYSIS OF SULFUR IMPACT ON THE OXIDATION OF
PETROLEUM RESIDUES

Abstract
This study investigates the effect of introducing elemental sulfur into the oxidation feedstock during the production of oxidized petroleum bitumen.
Vacuum residue from fuel oil distillation and granular sulfur were used as the base materials. Oxidation experiments were carried out at 230 °C with controlled
air flow, varying the sulfur concentration from 0 % to 5 %. The results showed that introducing sulfur in optimal amounts (up to 2 %) significantly improves the
physical and mechanical properties of the resulting sulfur–bitumen binders — increasing penetration and ductility and lowering brittleness temperature —
compared to conventional oxidized bitumen. Higher sulfur concentrations (> 5 %) lead to process inefficiency and deterioration of binder properties. The
findings confirm that sulfur additives can be effectively used to intensify the oxidation process, enhance product quality, and optimize production parameters
for bitumen manufacturing.

Keywords oil bitumen, sulfur, needle penetration, tar, oxidation process, softening point

The existing technology for the production of oxidized bitumen, due to the often
changing composition of petroleum feedstock for processing and the unstable quality of the
feedstock for the oxidation process, causes difficulties in obtaining bitumen of the required
quality. Therefore, directional regulation of the properties of the prepared raw materials for
the oxidation process is an urgent task.
Modern trends in the development of science and technology associate the solution of
this problem with the development of effective methods for influencing the properties of the
initial raw materials used in the production of commercial petroleum bitumen, optimizing the
technological parameters of the process for their production and adjusting the properties of
oxidized bitumen in various ways [1]. In the production of oxidized bitumen, an effective way of such exposure is to control the properties of the oxidation feedstock using various
additives.
We have studied elemental sulfur as such an additive, which is available in huge
quantities at oil refineries and gas refineries as by-products. Her choice is because the use of
elemental sulfur as a modifier to oil bitumen is currently expanding in the world in order to
improve their physical and mechanical properties [2]. The role of elemental sulfur is to
change the structure of petroleum bitumen due to reaction reactions with unsaturated
components and compounds of petroleum bitumen with the formation of sulfur-containing
compounds and supramolecular structures [3]. This circumstance should certainly affect the
results of the oxidation of raw materials with the addition of sulfur.

2. Methodology

The vacuum distillation tar of fuel oil of the Ferghana Oil Refinery was chosen as the
object of study, the main physicochemical properties of which are presented in Table 1.
Granular sulfur was used as elemental sulfur, obtained as a by-product in a process unit for
hydrodesulfurization of a fraction of diesel fuel (Table 2).
Samples of tar with the addition of sulfur in an amount of up to 5% to the tar were
prepared as raw materials.
The prepared tar and sulfur samples were oxidized in a 5-liter laboratory unit equipped with
a source for air circulation, a thermometer, and a refrigerator for cooling condensate vapor.
The charge of oxidation feed was 2 kg.
Oxidation was carried out at a temperature of 230 °C with constant air circulation in the
amount of 3 l/min per 1 kg of raw material until the softening point was reached to values
that meet the requirements of the current standard.

Table 1. Basic physical and chemical properties of tar

Properties

1. Density , kg/m3
2. Color
3. Compressive strength, MPa
4. Melting point, °С
5. Viscosity, Pа.s
6. Boiling point, °С
7. Heat capacity, kJ / kg
8. The degree of purity, %