Brayton-Cycle Solvent Recovery System. Phase II. System Design

摘要

The Brayton-cycle system described in this report was designed to recover the solvents evaporated in a 3M Company magnetic tape production facility. The major solvents utilized are MEK and toluene. The system was designed to receive the warm solvent/air mixture from the drying oven, remove the solvents by condensation, and return the warm air to the oven in a recirculating system. At the heart of the Brayton-cycle system approach is a newly designed electric-motor-driven turbocompressor. The turbine/compressor shaft is designed to operate at 16,500 rpm through single-stage helical step-up gears driven by a 3550-rpm 500-hp rated motor. The compressor is designed for a pressure ratio of 2.4 and the turbine for 2.25. The turbine/compressor and step-up gears are integrally designed for mounting to a framework with the motor. The assembly contains a lubrication system with redundant oil pumps and a water-cooled lube oil cooler. Instrumentation consists of shaft proximity probes, oil and bearing temperature sensors, accelerometers, and oil pressure transducers for controlling and monitoring system operation. Economic analysis shows that a simple payback for a similar magnetic tape installation is 1.9 yr - somewhat on the high side due to a high percentage of operation at reduced solvent evaporation rates. Paybacks of less than 1 yr are possible when operating at higher solvent concentrations and at approximately 2/3 of the available time. (ERA citation 09:018705)