OCR Text |
Show Case Study / Field Trial Results A permanent EFSOP™ system was installed at a major North American steel producer. The system became fully operational in February, 1996. A number of trial campaigns have been run since then, where several parameters, including the burner and lancing programs, have been modified. A baseline for the operation was established in February and March, 1996. During this time, furnace operation was relatively stable and all of the permanent instrumentation for E F S O P ™ had been installed and commissioned. This energy breakdown shows a substantial amount of energy lost to the furnace off-gas system during a typical heat. The off-gas profiles, shown in Figure 4, indicate that substantial incomplete combustion occurred for extended periods during both the first and second charge. Additional oxygen during these times should lead to improved energy efficiency through post-combustion. Preliminary trials with revised burner modes generated some savings. These trials showed a 12 kWh/t savings through enhanced combustion with relatively minor changes in practice. These preliminary results, combined with other process needs, led to the decision to install a new lance system during the 1996 summer shutdown. The advantages of this lance over the previous model in use are twofold. First, a higher maximum flow rate of O 2 can be injected to the furnace (2800 vs. 1600 scfm). Additionally, the lance pipes can be inserted into the furnace immediately after charging to deliver a high volume of oxygen throughout the meltdown phase. Several modes of operation for this lance were evaluated using the EFSOP™ analysis system. The most attractive scenario was the operation of the burners in a natural gas lean mode (introducing less than stoichiometric natural gas) for much of the heat. The off-gas profiles from this trial are shown in Figure 5. 8 |