OBTAINING BOILER FUEL FROM WASTE OF USTYURT GAS CHEMICAL COMPLEX IN THE REPUBLIC OF UZBEKISTAN AND DETERMINING ITS ECONOMIC

ABSTRACT

This study investigates the process of obtaining boiler fuel from 10–12 tons per day of solid aggregate waste (tar product) generated by the polymer products plant in the Republic of Karakalpakstan, and evaluates its economic efficiency. Under laboratory conditions, 2 kg of tar product yielded 1 liter of boiler fuel and 0.830 kg of carbon residue. Gas chromatography–mass spectrometry (GC–MS) analysis revealed the presence of aromatic hydrocarbons in the obtained fuel. The research results demonstrate the potential of processing waste products to obtain valuable materials. An industrial-scale project analysis indicated an annual revenue of 2.22 million USD, profitability of 60–70%, and a payback period of 2–3 years.

АННОТАЦИЯ

В данной исследовательской работе изучается процесс получения котельного топлива из 10–12 тонн в сутки твердых отходов (битумного продукта), образующихся на заводе по производству полимерной продукции в Республике Каракалпакстан, и оценивается его экономическая эффективность. В лабораторных условиях из 2 кг битумного продукта был получен 1 литр котельного топлива и 0,830 кг углеродного остатка. Анализ методом газовой хроматографии–масс-спектрометрии (ГХ–МС) показал наличие ароматических углеводородов в полученном топливе. Результаты исследования демонстрируют возможность переработки отходов для получения ценных материалов. Экономический анализ проекта промышленного масштаба показал годовой доход в 2,22 миллиона долларов США, рентабельность 60–70% и срок окупаемости 2–3 года.

Keywords: polymer waste, tar product, boiler fuel, pyrolysis, recycling, economic analysis.

Ключевые слова: полимерные отходы, битумный продукт (смола), котельное топливо, пиролиз, переработка, экономический анализ.

INTRODUCTION

In modern chemical industry, the recycling of waste products is becoming increasingly relevant [1:308]. The utilization of waste generated at polymer production plants is of great economic and environmental importance [2:1]. Numerous global studies have been conducted on obtaining fuel from polymer waste [3:1]. William, Richard, Hillary, and Michael (2021) studied the technology of obtaining fuel through pyrolysis of plastic waste.

Uzbek researchers have also made significant contributions in this field. To‘xtayev, Musoyeva, and others (2025) conducted fundamental research on developing alternative fuels from local raw materials. The polymer products plant in the Republic of Karakalpakstan produces 8,000 tons of polyethylene pipes and packaging materials annually; however, 10–12 tons of tar (production waste) are generated daily in the process.

The aim of our scientific research is to develop a technology for obtaining boiler fuel from the tar waste generated during this plant’s production process and to determine the economic feasibility of its industrial implementation.

RESEARCH METHODOLOGY

Laboratory Experiments: The research was carried out in the chemistry laboratory of Fergana State University. A special stainless-steel reactor with a 5-liter capacity, equipped with electronic temperature sensors and a water-cooling system, was used for the experiment. The thermal decomposition process of the tar product was carried out at temperatures of 300–420°C [4:467].

The pyrolysis process was performed at 300–420°C for 1.5–2 hours, using 2 kg of raw material. The obtained product was condensed and analytically evaluated.

Table 1.

Experiment Parameters

Analysis Methods: The composition of the obtained product was determined using gas chromatography–mass spectrometry (GC–MS). Physicochemical characteristics were evaluated in accordance with the O‘zDSt.989:2010 standard [5].

Economic analysis methodology: Industrial-scale planning was evaluated based on the following economic indicators [6:3561]:

• Net Present Value (NPV)
• Internal Rate of Return (IRR)
• Payback Period
• Annual Revenue and Profit

Results and discussion: As a result of laboratory research, 1 liter of boiler fuel and 0.830 kg of carbon residue were obtained from 2 kg of tar product. These results are close to those reported by Dwivedi et al. (2019) in their study on pyrolysis of polymer waste [7:2198]. It has been confirmed that HDPE waste can be completely pyrolyzed at 330–490°C within 2–3 hours [8:1].

The quality of the obtained products was analyzed using the chromato-mass spectrometry (GC-MS) method.

Figure 1. GC–MS spectrum of the obtained boiler fuel

Table 2.

Composition of the obtained fuel (GC–MS analysis)

The GC–MS analysis revealed that the obtained fuel mainly contains aromatic hydrocarbons. Compared to the O‘zDSt.989:2010 standard [5], differences were observed in fraction composition, cetane number, and resin content. Due to the low sulfur content, the fuel is suitable for use as boiler fuel.

Industrial-scale design

A plant design was developed to process 10–12 tons of tar waste per day from the Ustyurt gas-chemical complex. The technological scheme consists of the following main stages:

1. Raw Material Preparation: Cleaning and homogenization of tar product

2. Pyrolysis Process: Thermal decomposition at 300–420°C

3. Condensation: Separation of liquid product

4. Purification: Cleaning and stabilization of the obtained fuel

5. Packaging: Storage of the final product

Industrial-scale planning

The planning of a recycling plant based on 10-12 tons of daily tar waste from the Ustyurt Gas Chemical Complex was carried out. The annual production capacity was calculated based on an average daily waste amount of 11 tons.

Table 3.

Annual production forecast

Economic Efficiency. Based on international market prices, the main financial indicators of the project were determined [9:676233]. The following were determined from the revenue calculations. Table 4.

Table 4.

Annual Revenue Forecast

To enhance process efficiency, it is recommended to implement gas recirculation technology [12:1821129], which aligns with the energy-efficient concept proposed by Norkhojaeva et al.

CONCLUSION

The research results show that valuable products can be obtained from polymer production waste. From 2 kg of tar (resin), 1 liter of fuel was obtained with a 50% yield. The solid residue can be used in electrode production and as an adsorbent. Large-scale implementation of the technology ensures both ecological and economic benefits. Economic calculations indicate high profitability (ROI 60–70%) and a short payback period (2–3 years) [10:100091]. These figures correspond with other studies [11:593]. With an annual net profit of 1,7–2,1 million USD, the project is highly efficient. Production of boiler fuel and sulfur-free carbon electrodes will enable import substitution and foreign currency savings.

Further research should focus on pilot project implementation and organizing industrial-scale production. Pyrolysis technology remains a promising solution for recycling mixed plastic waste [13:1].

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