What is the primary environmental concern associated with coke formation in steam cracking furnaces?

The primary environmental concern associated with coke formation in steam cracking furnaces is increased energy consumption and greenhouse gas emissions due to the reduced heat transfer efficiency and the need for frequent decoking cycles. Coke is a carbonaceous solid that forms on the inner surfaces of the furnace tubes during the cracking process due to the polymerization and condensation of hydrocarbons at high temperatures. This coke layer acts as an insulator, reducing the heat transfer efficiency from the furnace to the process gas inside the tubes. To maintain the desired cracking temperature, the furnace firing rate must be increased, leading to higher fuel consumption and, consequently, increased emissions of carbon dioxide (CO2), a major greenhouse gas. Furthermore, the accumulation of coke necessitates periodic shutdowns of the furnace for decoking, a process where the coke is removed by burning it off with steam and air (or other methods). This decoking process also results in the release of CO2 and other pollutants, such as nitrogen oxides (NOx) and sulfur oxides (SOx), contributing to air pollution and climate change. The disposal of removed coke can also present an environmental challenge. Therefore, minimizing coke formation is crucial for improving energy efficiency, reducing greenhouse gas emissions, and minimizing air pollution in steam cracking operations.