MATERIAL BALANCE OF THE PROCESS FOR OBTAINING SYNTHETIC ALPHA-OLEFIN OILS FROM LOW-MOLECULAR-WEIGHT POLYMER WASTE

ABSTRACT

This article presents the calculation of the material balance for the process of obtaining alpha-olefin (AO) oils from low-molecular-weight polymer waste (LMPW). The study focuses on the production of a dispersion medium used in the manufacturing of plastic lubricating materials. The material balance of the recycling process was calculated based on 1200 t/year of raw material with an annual operating time of 8000 hours. The technological stages include vacuum filtration and fractionation. The results demonstrate that the process yields 5% (60 t) polymer residue, 62.7% (752.4 t) light fraction, and 32.3% (387.6 t) synthetic AO-type oil. The findings confirm the environmental and economic feasibility of recycling industrial polymer by-products.

АННОТАЦИЯ

В статье представлен расчет материального баланса процесса получения альфа-олефиновых (АО) масел из низкомолекулярных полимерных отходов (НМПО). Работа сфокусирована на получении дисперсионной среды, используемой в производстве пластичных смазочных материалов. Расчет материального баланса выполнен исходя из переработки 1200 т/год сырья при годовом фонде рабочего времени 8000 ч. Технологический процесс включает стадии вакуумной фильтрации и фракционирования. Результаты показывают, что в процессе получается 5% (60 т) полимерного остатка, 62,7% (752,4 т) легкой фракции и 32,3% (387,6 т) синтетического масла типа АО. Полученные данные подтверждают экологическую и экономическую целесообразность переработки промышленных полимерных побочных продуктов.

Keywords: waste, dispersion medium, material balance, fraction, vacuum, polymer, residue, mass fraction, raw materials, consumption, filter, formula, product, ton, technology, oil.

Ключевые слова: отход, дисперсионная среда, материальный баланс, фракция, вакуум, полимер, остаток, массовая доля, сырьё, расход, фильтр, формула, продукт, тонна, технология, масло.

Introduction. The global production of polymers has led to a critical accumulation of waste, necessitating advanced recycling technologies. Low-molecular-weight polymer waste (LMPW) is a significant byproduct of polyethylene and polypropylene production, often posing disposal challenges. Modern research emphasizes chemical recycling as a sustainable path to transform these wastes into high-value chemical feedstocks and lubricants [1]. Recent studies by global researchers have demonstrated that thermal and catalytic degradation of polyolefins can produce synthetic oils with properties comparable to commercial base oils [2].

In particular, the synthesis of alpha-olefins from alternative hydrocarbon sources is gaining traction due to the depletion of traditional oil reserves. According to international practice, the integration of vacuum distillation and filtration processes allows for the efficient separation of heavy residues from light synthetic fractions [3]. This approach not only addresses environmental issues but also enhances the resource base for the lubricants industry [4].

In this study, the material balance of the recycling process for LMPW generated at the Shurtan Gas Chemical Complex was analyzed. The investigation focuses on the technological parameters of vacuum filtration and fractionation to optimize the yield of synthetic alpha-olefin oils.

Research methodology. The calculation of the material balance is of great importance in the process of obtaining a dispersion medium for PLM from LMPW. Based on the material balance, the quantity of polymer waste used as raw material and the ratio of substances included in the final product composition are determined. At the same time, losses, evaporation, and the amount of gases released during the waste recycling process are evaluated. Based on these calculations, the optimal process parameters are determined, enhancing the economic and environmental efficiency of the production process.

At the Shurtan Gas Chemical Complex,  thousand tons of LMPW are generated annually. The production technology at the complex operates with an annual working time fund of τ = 8000 hours. According to the experimental data, as a result of filtering the LMPW, a liquid fraction with a mass share of x₂ = 0,95 and a polymer component of the LMPW with x₁ = 0,05 were separated. It was determined that when the liquid fraction of LMPW is distilled up to a temperature of 245 ℃, a dense residue can be obtained with a mass fraction of x₄ = 0,34 [4].

Based on the obtained research data, the material balance of the technology for producing a dispersion medium from LMPW, used in the production of PLMs, was calculated below.

Material balance of the process

A flow diagram of the material balance was developed for the LMPW recycling technology (figure 1).

Figure 1. Flow diagram of raw materials, main products, and by-products in the LMPW recycling process

The material balance equation of the LMPW separation process by vacuum filtration, according to figure 1a, is as follows:

.

here:  – mass flow rate of LMPW as raw material;   – polymer of LMPW;  – liquid fraction of LMPW.

The material balance equation of the fractionation process of the LMPW liquid fraction, according to figure 1b, is as follows [5]:

here:  – mass flow rate of the LMPW liquid fraction;  – mass flow rate of the light fraction;  –  mass flow rate of AOW.

Results

The input raw material — LMPW amounts to 1200 tons, given an annual working time fund of τ = 8000 hours. The hourly mass flow rate of the raw material is determined using the following expression:

.

The quantities of products obtained during the vacuum filtration of LMPW are determined using the following expressions: the material balance of the LMPW separation process by vacuum filtration is presented in table 1.

Table 1.

Material balance of the LMPW separation process by vacuum filtration

In the process of LMPW separation by vacuum filtration, 1140 tons per year or 142.5 kg per hour of the LMPW liquid fraction is obtained.

Table 2

Material balance of the fractionation process of the LMPW liquid fraction

In the fractionation process of the LMPW liquid fraction, based on experimental results, the mass fraction of AOO was . Based on this, the amount of the light fraction is determined using the following expression: the quantities of products obtained from the fractionation of the LMPW liquid fraction are determined as follows: the material balance of the LMPW liquid fraction fractionation process is presented in table 2.

In the preparation of the material balance of the recycling process, gas emissions and losses that have an insignificant impact on the overall technological indicators were not taken into account.

Table 3.

Material balance of the LMPW recycling process

As a result of the performed calculations, it was determined that three types of products can be obtained from the processing of LMPW at the Shurtan Gas-Chemical Complex. The quantitative composition of the resulting products relative to the mass of raw material is presented in table 3.

Conclusion. In conclusion, the Shurtan Gas Chemical Complex generates approximately 1,200 tons of LMPW annually in its polymer product manufacturing unit. If this waste is redirected for recycling, it would reduce the environmental risks posed to the surrounding ecosystem. Moreover, reprocessing it into semi-finished and finished products could provide economic benefits and potentially contribute to extending the resource base of oil and petroleum products.

Research results have scientifically demonstrated, through experimental methods, that from 5% (60 tons) of PW, it is possible to obtain 32.3% AOO (387.6 tons of synthetic oil) and 62.7% liquid fraction (752.4 tons of light hydrocarbons). The obtained AOO, when blended with mineral oils to achieve the required properties and specifications, can serve as a dispersive medium in the production of PLMs. The remaining products can be used as secondary raw materials in various industrial sectors.

References:

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3. Zia K.M., Bhatti I.A., Bhatti H.N. Methods for recycling and recovery of polyethylene terephthalate. Chemosphere, 2015, vol. 119, pp. 1-15.
4. Тиллоев Лочин Исматиллоевич, Усмонов Хуршиджон Рашид Угли, & Хамидов Дилшоджон Ганиевич (2020). Техническая классификация отходов в газовых химических комплексах. Universum: технические науки, (5-2 (74)), 74-78.
5. Dilshodjon, K., Sadriddin, F., & Lochin, T. (2025). IR SPECTRAL ANALYSIS OF THE LIQUID FRACTION FROM POLYMER WASTE. Universum: технические науки, 9(4 (133)), 37-40.