Take a Load Off Loading

摘要

WITH INTERMITTENT operations, getting a line to process temperature may become a large factor in thermal load — and can pose significant extra costs, as one plant discovered. The plant exported refrigerated products using relatively small coastal vessels. Product went from a re frigerated tank via a roughly 10,000-ft. long intermittent-use pipeline to a vessel (Figure 1). Historically, weeks would pass between vessel loadings. To speed loading, a line brought vaporized product back to a gas-recovery compressor in the process unit. The vessels had sufficient vapor-compression capacity to boost recycle vapor down the return line. For many years the plant ran this system without much thought.