Comparison of Byproduct and Heat-recovery Cokemaking Technologies

摘要

Both byproduct and heat-recovery coke plant technologies are capable to produce high quality coke suitable for high productivity blast furnaces. The decision as to which type of plant to build looked at from a return on investment viewpoint comes down to how the coke plant is integrated into the overall steel plant and what external energy sources are available to the plant. In Case 1 due to the lack of available of electricity from the grid, and reliance on an expensive alternative fuel source, fuel oil required to generate the electricity, the heat-recovery coke plant was preferred. In Case 2, when both electricity and natural gas were available at a low cost, the byproduct plant was shown to be the preferred option, although the sensitivity analysis showed that increases in electricity and gas prices could change this outcome. From an environmental viewpoint the heat-recovery technology had a smaller footprint than the byproduct technology. Due its negative pressure operation and incineration of all the volatile matter in the coal, the heat-recovery process is less susceptible to toxic gas releases. The coal bed configuration also means particulate emissions are reduced. The US Environmental Protection Agency (EPA) recognizes the heat-recovery process as meeting the Maximum Achievable Control technology (MACT). The byproduct process has some technologies that can improve upon the standard design such as individual oven pressure control and Coke Stabilisation Quenching (CSQ), which can minimize particulate and toxic emissions. The selection of the coke making technology must be made on a case-by-case basis. Many different factors can affect the decision including for example, available land and energy sources, steel plant configuration and energy consumers, environmental issues and the capital cost of equipment.