The ‘magic’ of magnesium
While petcoke is a less expensive fuel option, its use can lead to operational challenges for the cement plant, such as the formation of kiln rings and build-ups in the lower cyclones of the preheater. To optimise combustion and avoid these issues, Nuh Çimento has trialled a magnesium-based chemical additive that helps control the impact of high-sulphur fuels. By Seyda Arikan, Nuh Çimento, Turkey, and Jose Hernandez, EES Services, Mexico.
Figure 1: vanadium oxide complexes and their melting points
When compared with the use of coal or other fuels, the use of petcoke, although more economical, presents a number of challenges for the cement plant operator. It is often the case that cheaper petcoke has a higher sulphur content, which leads to the formation of build-ups in the lower preheater cyclones and rings in the kiln. This results in operational issues such as:
• decreased combustion efficiency
• operational instability
• reduced use of alternative fuels
• unscheduled shutdowns to clear the obstructions in the kiln or preheater
• long and risky cleaning activities at the kiln inlet and the cyclones
• false air entering the kiln as a result of the clean-up.
