PHE 1 general (plate heat exchanger)

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.

Flow principle and parts

The Gasketed Plate Heat

Exchanger – The PHE –

• The function of the plate pack – Single pass:

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

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:

PHE groupings influence on

performance

Example

• Product: 5 000 kg/h raw milk, inlet temp 20º C

• Service: 15 000 kg/h water, inlet temp 1º C

1 * 8

1 * 8 Example

Parallell grouping

• Low pressure drop

• Low heat transfer

Grouping Temp

program, ºC

Pressure drop, kPa

k-value, W/m², ºC

Heat transfer, kW

1 * 8 L

1 * 8 L

20 ! 9.0

4.4  1

3 21

1 * 8 H

1 * 8 H

20 ! 6.0

5.4  1

12 105

1 * 8 MH

1 * 8 ML

20 ! 7.7

4.8  1

5 45

8 * 1

8 * 1 Example

Series grouping

PHE groupings influence on

performance

Grouping Temp

program, ºC

Pressure drop, kPa

k-value, W/m², ºC

Heat transfer, kW

8 * 1 L

8 * 1 L 20 ! 2.56.5  1 10909450 6180 96

8 * 1 H

8 * 1 H 20 ! 1.66.7  1 495005750 8690 101

8 * 1 MH

8 * 1 ML

20 ! 1.9 6.6  1

2400 19700

•High pressure drop

•High heat transfer

4 * 2

4 * 2 Example

Combined grouping (symmetric)

PHE groupings influence on

performance

program, ºC

Pressure drop, kPa

k-value, W/m², ºC

Heat transfer, kW

4 * 2 L

4 * 2 L

20 ! 4.0 6.0  1

140 1210

4 * 2 H

4 * 2 H 20 ! 2.46.5  1 6350740 6300 96

4 * 2 MH

4 * 2 ML

20 ! 3.2 6.2  1

315 2580

4 * 2

2 * 4 Example

Combined grouping (asymmetric)

PHE groupings influence on

performance

program, ºC

Pressure drop, kPa

k-value, W/m², ºC

Heat transfer, kW

4 * 2 L

2 * 4 L

20 ! 4.8

5.7  1

140 160

4 * 2 H

2 * 4 H

20 ! 3.1

6.3  1

740 815

4 * 2 MH

2 * 4 ML 20 ! 3.96.0  1 315340 4390 88

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

-Heat Recovery

Product inlet

Pasteurisation temperature

C

IW

Cooler Regenerative Heater

C

B - A

C - A

Example: A = 4°C 67 - 4 63

B = 67°C 74 - 4 70

C = 74°C

Heat recovery = x 100 (%)

x 100 = x 100 = 90 %

Heat Recovery

Milk Pasteurizer

0

10000

20000

30000

40000

50000

60000

70000

80000

Regenerative

Series1