Heat recovery apparatus

Patent metadata

Field	Value
Publication number	US-9612045-B2
Application number	US-201414392187-A
Country	US
Kind code	B2
Filing date	Jun 20, 2014
Priority date	Jun 24, 2013
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

The present application relates to a heat recovery apparatus and a method thereof, according to the heat recovery apparatus and a method thereof according to an embodiment of the present application, steam of 120° C. or more may be generated using only one heat exchanger using waste heat of a low-grade heat source in the state of a sensible heat of 70° C. or more discharged in industrial sites or various chemical processes, for example, such as a manufacturing process of petrochemicals, and the generated steam may also be used in various processes, and thus the use of high temperature steam which is an external heat source to be used in a reactor or a distillation column may be decreased, thereby maximizing energy saving efficiency.

First claim

The invention claimed is:

1. A heat recovery apparatus, comprising:
a first heat exchanger, a compressor, a second heat exchanger, and a pressure drop device which are fluidically connected through a pipe through which a refrigerant flows,
wherein a refrigerant flow flowing into the first heat exchanger is heat-exchanged with a fluid flow of 70° C. or more flowing into the first heat exchanger,
the refrigerant flow flowing out of the first heat exchanger flows into the compressor, the refrigerant flow flowing out of the compressor flows into the second heat exchanger, and is heat-exchanged with a fluid flow flowing into the second heat exchanger,
the refrigerant flow flowing out of the second heat exchanger flows into the pressure drop device,
the refrigerant flow flowing out of the pressure drop device reflows into the first heat exchanger, and
a ratio between a pressure of the refrigerant flow flowing out of the first heat exchanger and a pressure of the refrigerant flow flowing out of the compressor satisfies the following Expression 1:
3.1 ≦P C /P H ≦4.2  [Expression 1]

where, in Expression 1, P C denotes a pressure of the refrigerant flow flowing out of the compressor, and P H denotes a pressure of the refrigerant flow flowing out of the first heat exchanger,
wherein the fluid flowing into the second heat exchanger is water, and the water which is heat-exchanged in the second heat exchanger is discharged as steam, and
wherein a temperature of the steam is 120° C. or more.

2. The heat recovery apparatus of claim 1 , wherein the fluid flow flowing into the first heat exchanger is a waste heat flow or a flow of condensate passed through a condenser.

3. The heat recovery apparatus of claim 1 , wherein a temperature of the refrigerant flow flowing out of the first heat exchanger and a temperature of the fluid flow flowing into the first heat exchanger satisfy the following Expression 2:
1° C.≦ T F −T R ≦20° C.  [Expression 2]

where, in Expression 2, T F denotes a temperature of the fluid flow flowing into the first heat exchanger, and T R denotes a temperature of the refrigerant flow flowing out of the first heat exchanger.

4. The heat recovery apparatus of claim 1 , wherein a flow rate of the refrigerant is in the range of 5,000 to 231,000 kg/hr.

5. The heat recovery apparatus of claim 1 , wherein a temperature of the refrigerant flow flowing into the first heat exchanger is in the range of 60 to 105° C.

6. The heat recovery apparatus of claim 1 , wherein a flow rate of the fluid flow flowing into the first heat exchanger is in the range of 50,000 to 2,300,000 kg/hr.

7. The heat recovery apparatus of claim 1 , wherein a temperature of the fluid flow flowing out of the first heat exchanger is in the range of 68 to 102° C.

8. The heat recovery apparatus of claim 1 , wherein a temperature of the refrigerant flow flowing out of the first heat exchanger is in the range of 65 to 105° C.

9. The heat recovery apparatus of claim 1 , wherein a pressure of the refrigerant flow flowing out of the first heat exchanger is in the range of 3.0 to 20.0 kgf/cm 2 g.

10. The heat recovery apparatus of claim 1 , wherein a temperature of the refrigerant flow flowing out of the compressor is in the range of 125 to 185° C.

11. The heat recovery apparatus of claim 1 , wherein a pressure of the refrigerant flow flowing out of the compressor is in the range of 9.0 to 62.5 kgf/cm 2 g.

12. The heat recovery apparatus of claim 1 , wherein a flow rate of the fluid flow flowing into the second heat exchanger is in the range of 500 to 10,000 kg/hr.

13. The heat recovery apparatus of claim 1 , wherein a temperature of the water flowing into the second heat exchanger is in the range of 70 to 105° C.

14. The heat recovery apparatus of claim 1 , wherein a pressure of the steam is in the range of 0.99 to 10.5 kgf/cm 2 g.

15. The heat recovery apparatus of claim 1 , further comprising one or more steam compressors configured to compress the steam.

16. The heat recovery apparatus of claim 1 , further comprising one or more steam condensers configured to condense the steam.

17. The heat recovery apparatus of claim 1 , wherein a temperature of the refrigerant flow flowing out of the second heat exchanger is in the range of 125 to 190° C.

18. The heat recovery apparatus of claim 1 , wherein a temperature of the refrigerant flow flowing out of the pressure drop device is in the range of 65 to 105° C.

19. A heat recovery method, comprising:
a refrigerant circulation step in which a refrigerant flow flows into a first heat exchanger, the refrigerant flow flowing out of the first heat exchanger flows into a compressor, the refrigerant flow flowing out of the compressor flows into a second heat exchanger, the refrigerant flow flowing out of the second heat exchanger flows into a pressure drop device, and the refrigerant flow flowing out of the pressure drop device flows into the first heat exchanger;
a first heat exchange step in which the refrigerant flow flowing into the first heat exchanger is heat-exchanged with a fluid flow of 70° C. or more flowing into the first heat exchanger;
a second heat exchange step in which the refrigerant flow flowing out of the compressor exchanger is heat-exchanged with a fluid flow of flowing into the second heat exchanger; and
a pressure adjustment step in which a ratio between a pressure of the refrigerant flow flowing out of the first heat exchanger and a pressure of the refrigerant flow flowing out of the compressor is adjusted to satisfy the following Expression 1:
3.1 ≦P C /P H ≦4.2  [Expression 1]

where, in Expression 1, P C denotes a pressure of the refrigerant flow flowing out of the compressor, and P H denotes a pressure of the refrigerant flow flowing out of the first heat exchanger,
wherein the fluid flowing into the second heat exchanger is water, and the water which is heat-exchanged in the second heat exchanger is discharged as steam, and
wherein a temperature of the steam is 120° C. or more.

20. The heat recovery method of claim 19 , wherein the fluid flow flowing into the first heat exchanger is a waste heat flow or a flow of condensate passed through a condenser.

21. The heat recovery method of claim 19 , further comprising adjusting a temperature of the refrigerant flow flowing out of the first heat exchanger and a temperature of the fluid flow flowing into the first heat exchanger to satisfy the following Expression 2:
1° C.≦ T F −T R ≦20° C.  [Expression 2]

where, in Expression 2, T F denotes a temperature of the fluid flow flowing into the first heat exchanger, and T R denotes a temperature of the refrigerant flow flowing out of the first heat exchanger.

22. The heat recovery method of claim 19 , wherein a pressure of the steam is in the range of 0.99 to 10.5 kgf/cm 2 g.

23. The heat recovery method of claim 19 , further comprising compressing the steam.

24. The heat recovery method of claim 19 , further comprising condensing the steam.

Assignees

• Lg Chemical Ltd

Inventors

• Lee Sung Kyu
• Shin Joon Ho
• Kim Tae Woo

Classifications

• B01D3/007

  Energy recuperation; Heat pumps · CPC title

• F25B27/00

  Machines, plants or systems, using particular sources of energy (F25B30/06 takes precedence) · CPC title

• F24H4/04

  Storage heaters · CPC title

• F25B2700/21161

  of the fluid heated by the condenser · CPC title

• F24D2200/16

  Waste heat · CPC title