Đang tải... (xem toàn văn)
Tài liệu thiết bị trao đổi nhiệt dạng tấm PHE (plate heat exchanger) của Alfalaval, Hướng dẫn tổng quan về các kiểu PHE, khả năng ứng dụng cho từng loại sản phẩm và hướng dẫn tính toán, lựa chọn loại, công suất PHE phù hợp.
PHE General Flow principle and parts The Gasketed Plate Heat Exchanger – The PHE – • The function of the plate pack – Single pass: PHE General The Gasketed Plate Heat Exchanger – The PHE – • The function of the plate pack – Multi pass: The Gasketed Plate Heat Exchanger – The PHE – • The plate corrugation has two functions: Mechanical Flow dynamic PHE General The Gasketed Plate Heat Exchanger – The PHE – • Two plate corrugations L and H: L: Low theta H: High theta The Gasketed Plate Heat Exchanger – The PHE – • Two plate corrugations may form three different interplate channels: L + L = L channels H + H = H channels L + H = M channels PHE General PHE groupings influence on performance Example • • • • Product: 000 kg/h raw milk, inlet temp 20º C Service: 15 000 kg/h water, inlet temp 1º C PHE: Clip-6RM with 17 plates = 2,75m² Channels: Low, high and mixed theta Parallell grouping Example * 1*8 PHE General PHE groupings influence on performance • Low pressure drop • Low heat transfer Grouping Temp program, ºC Pressure k-value, Heat drop, kPa W/m², ºC transfer, kW * L * L 20 ! 9.0 4.4 21 1860 60 * H * H 20 ! 6.0 5.4 12 105 2980 76 * MH 20 ! 7.7 * ML 4.8 45 2280 67 Series grouping Example * 8*1 PHE General PHE groupings influence on performance •High pressure drop •High heat transfer Grouping Temp program, ºC Pressure drop, kPa k-value, W/m², ºC Heat transfer, kW * L * L 20 ! 2.5 6.5 1090 9450 6180 96 * H * H 20 ! 1.6 6.7 5750 49500 8690 101 * MH * ML 20 ! 1.9 6.6 2400 19700 7370 99 Combined grouping (symmetric) Example * 4*2 PHE General PHE groupings influence on performance Grouping Temp program, ºC Pressure drop, kPa k-value, W/m², ºC Heat transfer, kW * L * L 20 ! 4.0 6.0 140 1210 4260 87 * H * H 20 ! 2.4 6.5 740 6350 6300 96 * MH * ML 20 ! 3.2 6.2 315 2580 5150 92 Combined grouping (asymmetric) Example * 2*4 PHE General PHE groupings influence on performance Grouping Temp program, ºC Pressure drop, kPa k-value, W/m², ºC Heat transfer, kW * L * L 20 ! 4.8 5.7 140 160 3670 83 * H * H 20 ! 3.1 6.3 740 815 5280 93 * MH * ML 20 ! 3.9 6.0 315 340 4390 88 PHE General Milk pasteurization Parameters • • • • • • • • • Capacity Temp programme; in, out, past Running costs Running times Separation, temperature, skimming Homogenisation, temperature, pressure Deaeration, temperature, temperature drop Heating media, cooling media Drainability Milk pasteurization Heat Recovery • • • • • • • Capacity Running hours Cleaning intervals Media costs Product costs Maintenance Capital cost + + + + - PHE General Heat Recovery Product inlet Pasteurisation temperature IW A Cooler B C Regenerative D HW C B-A C-A Heat recovery = Example: Heater A = 4°C B = 67°C C = 74°C x 100 (%) 67 - 74 - x 100 = 63 x 100 = 90 % 70 Heat Recovery Milk Pasteurizer 80000 70000 60000 EUR 50000 Series1 40000 Series2 30000 20000 10000 75 80 85 90 95 100 Regenerative 10 ... transfer, kW * L * L 20 ! 9.0 4.4 21 1860 60 * H * H 20 ! 6.0 5.4 12 10 5 2980 76 * MH 20 ! 7.7 * ML 4.8 45 2280 67 Series grouping Example * 8 *1 PHE General PHE groupings influence on performance... L 20 ! 4.0 6.0 14 0 12 10 4260 87 * H * H 20 ! 2.4 6.5 740 6350 6300 96 * MH * ML 20 ! 3.2 6.2 315 2580 515 0 92 Combined grouping (asymmetric) Example * 2*4 PHE General PHE groupings influence... drop, kPa k-value, W/m², ºC Heat transfer, kW * L * L 20 ! 4.8 5.7 14 0 16 0 3670 83 * H * H 20 ! 3 .1 6.3 740 815 5280 93 * MH * ML 20 ! 3.9 6.0 315 340 4390 88 PHE General Milk pasteurization