Cement Energy and Environment

Government agency Table 1 Predicted and industry measured values with observed values for temperature, oxygen concentration and NO, concentration at the outlet gas stream of calciner con– figuration C1-l. FAPEMIG, as well as the collaboration of Cinar Ltd. clients in allowing the presentation of these MI– CFD specific mathematical modelling results pertaining to their equipment. Calciner exit Measured Predicted Temperature [°C] 883 870 0 2 concentration (% vol. dry basis] 2.85 2.96 NO, concentration (ppm] 830 791 In C3-l, the formation is observed of fuel NOx along the petcoke particles path and the absence of reburning conditions, as well fuel is injected in an oxygen lean region. In C3- II, 25% of the fuel is injected below the tertiary air inlet level. The petcoke particles injected by these burners are captured by a recirculation zone, created mainly by the abrupt expansion from the smoke chamber to the cone region. They recirculate in the cone, they release volatiles and consume oxygen in their path. The formulation of fuel NOx, is not favored and the Chi radicals react with the kiln-formed NOx (Figure 5). Fuel redistribution is responsible for 29% of the reduction in NOx emission at the calciner exit. 5 Final consideration Geometry and operational conditions are different in each of the studied Calciner. These conditions determine the fluid flow patterns within the equipment and thus mechanism involved in the formation and reduction of NOx. With MI-CFD modelling, it was possible to understand the complex phenomena, such as solid fuel combustion, Calcination, mixing and generation of atmospheric pollutants, occurring inside the studied Calciner. Regarding NOx emissions, it was demonstrated that it is possible to create or improving reburning conditions in different Calciners design. With simple modifications, NOx emissions reductions of 17 to 33% were achieved in the Calciners studied in the present work. Acknowledgements Authors gratefully acknowledge the financial support of the Brazilian % difference 1.5 3.9 4.9 REFERENCES [1] Abbas, T.; Lockwood, F. C.; Oimitrlou, D.: NO. formation and reduction: The modelling of SNCR. ZKG International, no8 (volume 60), pp. 52--58, 2007 [2] Akritopoulos, M .; Abbas, T.: Lower NO. & CO design. International Cement Review, May 2013 [3] Nance, G.; Abbas, T.; Lowes, T.: Bretz, J: Caldner design for lower CO and NO. using MI-CFD analysis to optimize Hot-Rebum Conditions. IEEE Cement Industry Technical Conference, 2011 Courtesy: ZKG International, Issue 11 2016, pg. 36-39 I J THE BIGGEST VRM FOR CLINKER GRINDING ! The United Cement Company of Nigeria (Ltd), UNICEM, commissioned their new cement plant 2 at Mfamosing, in Cross River State, Nigeria successfully in September 2016. LOESCHE received the order for two vertical roller mills: one type LM 60.4 for grinding cement raw materi al and one LM 70.4+4 CS, the biggest LOESCHE VRM built for grinding cement clinker. 32 , --