Cokefired

Cokefired refers to equipment or processes that use coke as the primary fuel and reducing agent, most notably in ironmaking and steelmaking. In this context, cokefired blast furnaces rely on coke to generate the high temperatures needed for smelting and to provide carbon monoxide, which reduces iron ore to iron.

Coke is produced by heating coal in the absence of air in coke ovens, a process called coking. This removes volatile components and yields a solid, porous, high-carbon fuel with substantial calorific value. The volatile by-products—such as coal gas, coal tar, and light oils—are collected and can be refined for other uses. The coke’s physical strength and porosity help maintain airflow and chemical reactions inside a blast furnace.

In operation, ore, flux, and coke are charged into the blast furnace. Hot air or oxygen-enriched air is blown from the bottom, causing coke to burn and raise the furnace temperature. The produced carbon monoxide reduces iron oxide to iron, while impurities form a slag. The process produces molten iron and slag, which are tapped periodically, and a blast of gases exits the furnace.

Environmental and economic considerations accompany cokefired systems. Coke production is energy-intensive and emits carbon dioxide, sulfur compounds, and other pollutants. The coke supply chain can also be sensitive to coal markets and transportation costs. As steel technologies evolved, many cokefired plants were modernized, converted to natural gas or pulverized coal injection, or replaced with alternative furnaces, though cokefired processes remain in use in some regions and for particular steel grades.

See also: coke oven, blast furnace, ironmaking, steelmaking, pulverized coal injection.