Development of Compact Gas-Fired Air Heating Systems for the Plastics Industry. Final Report March 1988-August 1989

摘要

A complete product line of gas-fired dehumidifying dryers was designed for the plastics drying industry. A total of nine separate models were selected to complete the product line, and the burners, heat exchangers, fuel/air trains, and control systems needed for these nine dryers were developed. Indirect cross flow heat exchangers with a design efficiency of greater than 70% were developed for all dryers. The heat exchangers were matched with Pyrocore(R) radiant burners which allowed for compact, efficient, cost effective designs. An aspirated fuel/air delivery system was developed to provide a constant fuel/air ratio feed to the burners regardless of firing rate. A high/low modulated firing rate was selected which allowed tight temperature control. The conceptualized product line ranges from 25 to 640 MBtu/hr (maximum heat input), and dryers in two of the proposed nine sizes were completely fabricated and tested. The CDG 400 (80 MBtu/hr) and the CDG 1600 (280 MBtu/hr) both performed well during testing. The CDG 400 was life tested for over 3700 hours with no major technical problems. During this time, the process heater cycled over 1,000,000 times between high and low fire.