DEVELOPMENT OF A HIGH-EFFICIENCY GAS-FIRED PAPER DRYER FOR DRYING LIMITED PAPER MILLS

摘要

Paper drying is the most energy-intensive and temperature-critical aspect of papermaking. It is estimated that about 67% of the total energy required in papermaking is used to dry paper. The conventional drying method uses a series of metal steam-heated cylinders those are required to meet ASME codes for pressure vessels, which limits the steam pressure to about 160 psig. Consequently, the shell temperature and the drying capacity are also limited. Gas Technology Institute together with Boise Paper Solutions, Groupe Laparrier and Verreault (GL&V) USA Inc., Flynn Burner Corporation and with funding support from the U.S. Department of Energy and the U.S. natural gas industry is developing a high efficiency gas-fired paper dryer based on combination of ribbon burner and advanced heat transfer enhancement technique. The Gas-Fired Paper Dryer (GFPD) is a high-efficient alternative to traditional steamheated drying drums that operate typically at surface temperatures in the 300oF range. The new approach was evaluated at the laboratory conditions following a pilot-scale testing at WMU Paper Plant. Drum surface temperature of about 500oF was reached with linerboard (basic weight 126 lb/3000 ft2) production that resulted in 4-5 times drying rate increase as opposed to existing steam heated can. Successful GFPD development and commercialization will provide large energy savings to the industry as well as increase a production rate from dryer-limited (space or steam limited) paper machines by an estimated 10 to 20%, resulting in significant capital costs savings for both retrofits and new capacity.