Technology for spouted bed drying of green malt

A spouted bed with spout region similar to a dilute phase fluidized bed and annulus region similar to a countercurrent closely moving bed has a simple structure and good effects of heat and mass transfer and may be used to dry green malt for replacing the present technology with packed bed in which heat and mass transfer is not even. Therefore, a spouted bed dryer was designed and tried with a column of 180 mm in inner diameter and 700 mm in height, a cone of 100 mm in height and 90° in conic angle, and a gas inlet of 25 mm inner diameter. Nine experiments of drying green malt were carried out with the spouted bed on conditions that 3 kg green malt was charged and air flow rate was 100 m³/h each time. The quality of malt was examined in terms of several indexes. The results indicated that a better drying technology was obtained when green malt was dried by 60℃ hot air for 4 h at first, then heated to 80℃ by 85℃ hot air, and baked by 85℃ hot air for 2.5 h at last stage. The processing time was obviously less than that of traditional technology. The energy consumption was about 5700 kJ/kg water that was dcreased by about 30% compared with the values at many malt production factories. The moisture content of dried malt was 4.74%(wb), Europe brewage corporation(EBC) color degree 4.25, soaking rate 81%, α-N 157.6 mg/(100 g), the difference between coarse powder and fine powder 1.5, mashing time 9 min. They all reached the standards of first-rate light color malt.