HEAT RECOVERY APPARATUS

• US 20160187036A1
• Filed: 06/20/2014
• Published: 06/30/2016
• Est. Priority Date: 06/24/2013
• Status: Active Grant

• Current Assignee: LG Chem Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: KIM, Tae Woo, LEE, Sung Kyu, SHIN, Joon Ho
• Granted Patent: US 9,612,045 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01D 3/007 Energy recuperation; Heat pumps
• CPC Class Codes: F24D 2200/16 Waste heat
• CPC Class Codes: F24H 4/04 Storage heaters
• CPC Class Codes: F25B 1/10 with multi-stage compression with cascade operation F25B7/00
• CPC Class Codes: F25B 2339/047 Water-cooled condensers
• CPC Class Codes: F25B 25/005 using primary and secondary systems
• CPC Class Codes: F25B 27/00 Machines, plants or systems, using particular sources of energy F25B30/06 takes precedence
• CPC Class Codes: F25B 27/005 in compression type systems
• CPC Class Codes: F25B 27/02 using waste heat, e.g. from internal-combustion engines
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/197 of the evaporator
• CPC Class Codes: F25B 2700/21152 at the discharge side of the compressor
• CPC Class Codes: F25B 2700/21161 of the fluid heated by the condenser
• CPC Class Codes: F25B 2700/21174 of the refrigerant at the inlet of the evaporator
• CPC Class Codes: F25B 2700/21175 of the refrigerant at the outlet of the evaporator
• CPC Class Codes: F25B 30/02 of the compression type
• CPC Class Codes: Y02A 30/274 using waste energy, e.g. from internal combustion engine
• CPC Class Codes: Y02P 20/10 Process efficiency
• CPC Class Codes: Y02P 70/10 Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

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.

Claims

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;

2≦

P_C/P_H≦

5  

 

[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.

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/cm² 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/cm² 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 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.

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

C.

15. The heat recovery apparatus of claim 13, wherein a temperature of the steam is 120°

C. or more.

16. The heat recovery apparatus of claim 13, wherein a pressure of the steam is in the range of 0.99 to 10.5 kgf/cm² g.

17. The heat recovery apparatus of claim 13, further comprising one or more steam compressors configured to compress the steam.

18. The heat recovery apparatus of claim 13, further comprising one or more steam condensers configured to condense the steam.

19. 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.

20. 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.

21. 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;

2≦

P_C/P_H≦

5  

 

[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.

22. The heat recovery method of claim 21, wherein the fluid flow flowing into the first heat exchanger is a waste heat flow or a flow of condensate passed through a condenser.

23. The heat recovery method of claim 21, 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.

24. The heat recovery method of claim 21, 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.

25. The heat recovery method of claim 24, wherein a temperature of the steam is 120°

C. or more.

26. The heat recovery method of claim 24, wherein a pressure of the steam is in the range of 0.99 to 10.5 kgf/cm² g.

27. The heat recovery method of claim 24, further comprising compressing the steam.

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