Retrocommissioning and Energy Efficiency - Applying this Concept to the Paper Machine Vacuum System

摘要

Paper machine vacuum systems have a reputation of being somewhat difficult to understand, troubleshoot and optimize. Problems associated with these vacuum systems often are not identified. This leads to the statement, "You can get the sheet to the reel with a poorly operating vacuum system". Besides the ongoing efforts to maintain and optimize all of the papermaking processes, consider that the vacuum system can have as much, or more, connected horsepower as the entire paper machine. This can be from 700 hp on a small, specialty machine, to 7000+ hp on a large linerboard machine. Paper machines and supporting processes are designed and installed based on expected ranges of production rates using specific furnishes, headbox consistency, chemistry, refining, retention, fabric design, etc. The configuration of the paper machine is determined based on mutually agreed criteria for these and other variables. The vacuum system is designed and installed to satisfy these production specifications. During the years and decades following installation, many of these operating variables can be, and are altered. However, the vacuum system consists of significant hardware and piping which usually experiences little modification. Retrocommissioning describes the process to identify and correct less-than-optimal performance within the vacuum system, without retrofitting or replacement of significant components. Concurrent to the optimization process is the ability to achieve significant energy reduction. Experience with Retrocommissioning of vacuum systems usually provides energy reduction of 10 - 15% of existing operating power. Some systems have had the potential to remove 20 - 25% of operating power. This presentation will explain the procedures of Retrocommissioning, as applied to the vacuum system, and includes case studies to emphasize the positive results from optimization.