The Alchemists of Industry

Introduction: More Than Just Coke

When you think of a steel mill, you might envision blast furnaces and molten metal. Yet, the heart of this industrial giant doesn't beat in its furnaces, but in its central plant laboratory. For a company like PAO Koks, a key player in the production of metallurgical coke, the laboratory is the nerve center where the quality of its primary product—and the economic viability of its entire operation—is determined.

This is the story of how scientists at PAO Koks harness sophisticated chemistry to transform coal into high-quality coke, while also capturing valuable by-products that would otherwise be lost. It's a tale of precision, innovation, and the relentless pursuit of efficiency in one of the world's most foundational industries.

The Science of Coking: A High-Temperature Transformation

What is Metallurgical Coke?

Metallurgical coke is a macroporous carbonaceous solid produced from the carbonization of specific rank coking coals at temperatures of about 1000 °C in the absence of oxygen. Its primary role is to act as a fuel and reducing agent in blast furnaces, which are used to convert iron ore into molten iron. The process not only creates coke but also generates volatile by-products, including coal tar, coke oven gas (COG), and ammonia² .

Metallurgical coke sample with porous structure

The Coking Process Unveiled

The journey from coal to coke is a dramatic one, governed by precise thermal conditions:

In a by-product coke plant, the volatile matter released during this process is not wasted. It is captured and channeled through a complex recovery system where it is cooled and separated into coal tar, ammonia liquor, and valuable coke oven gas (COG)² . The composition and yield of these by-products are directly influenced by the original coal blend and the precise conditions of the coking process.

A Key Experiment: Mastering the Yield of Volatiles

One of the most critical tasks for the Central Plant Laboratory at PAO Koks is the accurate assessment of coke quality and the prediction of by-product yields. A pivotal experiment in their repertoire involves determining the yield of volatiles from the coke sample.

Experimental Methodology

This procedure, refined and implemented at facilities like PAO Zaporozhkoks, provides a rapid and reliable assessment of the coking process's completeness⁴ .

Sample Preparation

A representative sample of the produced coke is crushed to a specific particle size to ensure consistency.

Heating

The sample is placed in a specialized furnace and heated to a standardized high temperature of 1150°C in an inert atmosphere, absent of oxygen.

Gas Collection and Measurement

The volatile gases released from the coke—primarily hydrogen, methane, and nitrogen—are collected. Unlike older gravimetric methods, the modern approach adopted by advanced laboratories measures the volume of these gases.

Data Analysis

The volume of gas released is precisely quantified and recorded as the "yield of volatiles by volume"⁴ .

Laboratory analysis of coke samples

Results and Analysis

The results from this experiment are deceptively simple—a single number representing the volume of gas—but its implications are profound. Research at PAO Zaporozhkoks revealed a close correlation between the yield of volatiles and two crucial coking parameters: the final coking temperature and the coking rate⁴ .

A high yield of volatiles indicates that the coking process was incomplete; the final temperature was likely too low, or the coking rate too fast, leaving residual volatile matter in the coke. This results in a weaker, less desirable coke for the blast furnace. Conversely, a low yield of volatiles signals a well-coked, stable product. By monitoring this value, the laboratory provides real-time feedback to the coking battery operators, enabling them to adjust the furnace temperature for optimal product quality.

The Scientist's Toolkit: Essential Reagents and Materials

The work of the central laboratory relies on a suite of specialized materials and analytical tools. Below is a breakdown of the key reagents and solutions essential for their experimental work, particularly in analyzing by-products.

The Bigger Picture: Economic and Environmental Impact

The meticulous work of the central laboratory extends far beyond quality assurance. It is fundamentally linked to the economic health and environmental footprint of the entire plant.

The by-products of coking are not mere waste; they are significant revenue streams. Coal tar, once processed, can be separated into fractions used in producing carbon fibers, pitch, and industrial chemicals. Coke oven gas, with a significant energy content of 16 to 20 MJ/Nm³, is often reused to heat the coking ovens themselves or for power generation, reducing the plant's external energy needs² . Furthermore, with the steel industry under pressure to reduce its CO2 emissions, the laboratory is on the front lines of researching new formulations, such as the addition of biomass to coking blends, to lower the overall carbon footprint² .

Conclusion: The Unsung Hero of Steel

The development of the Central Plant Laboratory at PAO Koks represents a quiet revolution in industrial manufacturing. It is a place where blacksmithing intuition has been replaced by data-driven precision, and where waste is systematically transformed into wealth. The scientists there are the unsung heroes of the steel industry, their work ensuring that every gram of coal is used to its maximum potential.