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Show PROCESS EQUIPMENT The important equipment components in this process scheme are the hot gas quench tank, batch/cullet preheater and the electrostatic precipitator. These are discussed briefly below. Quench Tank The flue gas quench tank must not only cool the hot flue gas to a usable temperature, but also collect the condensables coming off the glass tank. Both of these needs can be achieved with a well designed tank that has the correct residence time and flow patterns. The condensables, mostly sodium sulfate, will be cooled by the recycle gas and will collect as a liquid at the bottom of the quench tank from where they will be drained. Calculations indicate that the condensate load on the quench tank will be reduced because of the lower quantities of sodium sulfate emitted in an oxy-fuel glass melting operation. Batch/Cullet Preheater Batch preheating, as discussed earlier, is the most efficient and desired method of providing heat to the glass melting operation. However, several earlier methods at batch preheating have succumbed to technical or economic hurdles. Batch preheating poses significant challenges in material handling and uniform heat transfer. For good glass quality it is crucial to avoid inhomogeneities or segregation of the batch materials. Softening of any of the batch constituents must be carefully avoided by keeping temperatures well below levels at which this could pose a problem. Only recently has a system become commercially available that overcomes these challenges. This system, which has now been operating successfully for two years, utilizes direct heat exchange to preheat a mixture of batch and cul1et. Discussions with the company suppling this system indicate that it could be successfully used for an oxy-fue1 glass melting process. Electrostatic Precipitator The commercial facility using the batch/cu11et preheater described above also uses an electrostatic precipitator (ESP) to remove the carryover dust picked up from direct heat exchange with the batch and cu1let. Figure 7 shows an ESP being used in the oxy-fue1 case too. However, it is quite likely that an ESP could be dispensed with because of the much lower dust pickup due to the lower linear velocities with oxygen, and a cyclone separator may suffice. v. ENERGY EFFICIENCY AND ECONOMIC ANALYSIS This section presents an analysis of the operating and capital costs for the air-fuel process and the TEAM processes just discussed. For the oxy-fue1 processes, the raw material preheating process scheme is analyzed as well as the fired gas turbine and carbon dioxide/methane reforming process schemes. The latter two were found to provide the - 10 - |