Combination power generating system

Abstract

A combination power generating system includes a first power generating system, which boils water into steam to turn a first turbine for driving a first generator to generate electricity, and a second power generating system, which utilizes waste heat from the first power generating system to heat an organic solvent into organic vapor for turning a second turbine to drive a second generator to generate electricity.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to power generating technology and more particularly, to a combination power generating system, which comprises a first power generating system, and a second power generating system that utilizes waste heat from the first power generating system to heat an organic solvent into high-pressure organic vapor for turning a turbine to drive a generator for generating electricity.

2. Description of the Related Art

A conventional steam-driven power generating system, as shown in FIG. 1, generally comprises a steam boiler 10 holding a certain amount of water W, a heater 11 adapted to heat the water W in the steam boiler 10 into steam, a turbine 12 in communication with the steam boiler 10 and turned by steam produced by the steam boiler 10, a generator G is driven by the turbine 12 to generate electricity, a steam pipe 13 extended from one end of the turbine 12 remote from the steam boiler 10, a cooling pond 16, a water outlet pipe 17 for guiding hot water out of the cooling pond 16, a water inlet pipe 18 for guiding cooling water from an external water source into the cooling pond 16, a steam pipe 13 for guiding steam out of the turbine 12, a cooling coil pipe 14 extended from the steam pipe 13 through the cooling pond 16 for guiding steam through the cooling pond 16 for condensing into water, a return pipe 15 connected between the cooling coil pipe 14 and the steam boiler 10, and a motor pump MP mounted in junction between the cooling coil pipe 14 and the return pipe 15 for pumping condensed water from the cooling coil pipe 14 back into the steam boiler 10.

The aforesaid prior art of power generating system is still not satisfactory in function because of the drawbacks that this power generating system has low efficiency and wastes much heat energy. When steam is produced to turn the turbine 12, a big amount of cooling water is circulated through the cooling pond 16 to cool down steam into water for recycling. According to analysis, about 33% of heat energy is converted into electricity (net output) and about 7% of heat energy is consumed internally (in turbine, piping and motor pump), and about 60% of heat energy is wasted in heat exchange between the cooling coil pipe 14 and cooling water in the cooling pond 16.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a combined power generating system, which utilizes waste heat to enhance power generation, saving energy consumption.

To achieve this and other object of the present invention, a combination power generating system comprises a first power generating system, which boils water into steam to turn the first turbine for driving the first generator to generate electricity, and a second power generating system, which utilizes waste heat from the first power generating system to heat an organic solvent into organic vapor for turning the second turbine to drive the second generator to generate electricity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system block diagram of a power generating system according to the prior art.

FIG. 2 is a system block diagram of a combined power generating system according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 2, a combined power generating system in accordance with the present invention is shown comprising a first power generating system 100 and a second power generating system 200.

The first power generating system 100 comprises a steam boiler 10, a heater 11 adapted to heat water W in the steam boiler 10 into steam, a turbine 12 is connected with the steam boiler 10, a generator G1 coupled to the turbine shaft of the turbine 12, a steam pipe 13 extended from one end of the turbine 12 remote from the steam boiler 10, a cooling coil pipe 14 connected to one end of the steam pipe 13 remote from the turbine 12, and a return pipe 15 connected between the other end of the cooling coil pipe 14 and the steam boiler 10, and a motor pump MP1 mounted in junction between the cooling coil pipe 14 and the return pipe 15 to pump condensed water from the cooling coil pipe 14 back into the steam boiler 10.

The second power generating system 200 comprises a boiler 20 that holds the cooling coil pipe 14 to enable a solvent H in the boiler 20 to be heated into organic vapor by steam that flows through the cooling coil pipe 14, a turbine 22 is connected with the steam boiler 20, a generator G2 coupled to the turbine shaft of the turbine 22, a cooling pond 24, a water outlet pipe 25 for guiding hot water out of the cooling pond 24, a water inlet pipe 26 for guiding cooling water from an external water source into the cooling pond 24, a cooling coil pipe 23 extending through the cooling pond 24 and connected between the turbine 22 and the boiler 20, and a motor pump MP2 is set for pumping condensed fluid from the cooling coil pipe 23 back to the boiler 20. Further, sea water can be pumped by MP3 into the cooling pond 24 for cooling the organic vapor that flows through the cooling coil pipe 23.

During operation, the heater 11 heats water in the steam boiler 10 of the first power generating system 100 into high-pressure high-temperature steam that turns the turbine 12, causing the generator G1 of the first power generating system 100 to generate electricity. High-pressure high-temperature steam that goes through the turbine 12 become low-temperature low-pressure steam (120° C., 290 psi) and it is guided into the cooling coil pipe 14 to heat the low boiling point of solvent H in the boiler 20 of the second power generating system 200 into high-pressure organic vapor that turns the turbine 22, causing the generator G2 of the second power generating system 200 to generate electricity. After passing through the cooling coil pipe 14 to make heat exchange with the solvent H in the boiler 20, steam is condensed into water and pumped by the motor pump MP1 back to the steam boiler 10. Organic vapor that flows through the cooling coil pipe 23 is cooled down by cooling water circulating through the cooling pond 24 and condensed into solvent H that is pumped by the motor pump MP2 back to the boiler 20.

As stated above, the second power generating system 200 utilizes waste heat from the first power generating system 100 to heat the solvent H into organic vapor for driving the turbine 22 to cause the associating generator G2 to generate electricity.

Various solvents can be selectively used according to the cooling condition. A solvent relating function such as “more thermal efficiency” and “more electricity generated” is listed in table 1:

TABLE 1
	Boiling	More thermal	More electricity
Organic Solvent	point (° C.)	efficiency (%)	generated (%)
Ethanol	78	2.8	8.5
Methanol	64.5	4.2	12.7
2,2, Dimethyl Butane	50	5.5	16.7
Dichloromethane	41	6.4	19.3
n-Pentane	36	6.8	20.6
Isopentane	28	7.5	22.7
Monochloroethane	12.5	9.0	27.3
Neopentane	9.5	9.4	28.5
n-Butane	0	10.2	30.9

Interpretation of table 1:
1. In the conventional power generating system, if 100 cal of heat is produced from heater 11, only 33 cal is converted into electricity (net output). In table 1, take methanol as example, 4.2 cal of heat is converted into electricity. The calculation equation is shown as the following:

More thermal efficiency=4.2/100×100%=4.2%

More electricity generated=4.2/33×100%=12.7%

2. The boiling point of the chosen organic solvent must be higher than the cooling water applied in the cooling pond 24.

As indicated in the above table, waste heat from the first power generating system can drive the second power generating system to increase electricity generation by about 7.3%˜30%. It requires cooling water to cool down the organic vapor produced during operation of the second power generating system.

Further, a partition wall 27 is set between the first power generating system 100 and the second power generating system 200 to prohibit entering of organic vapor from the second power generating system 200 into the first power generating system 100 in case of a leakage and to avoid damage to both the two power generating system.

Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.

Claims

1. A combination power generating system, comprising:

a first power generating system, said first power generating system comprising a first generator for generating electricity, a first turbine for rotating said first generator to generate electricity, a first steam boiler holding a predetermined amount of water, heater means for heating the water in said first steam boiler into steam for turning said first turbine in driving said first generator to generate electricity, and a first cooling coil means for cooling the steam passing through said first turbine into condensed water and guiding the condensed water back to the said first steam boiler; and

a second power generating system, said second power generating system comprising a second boiler holding an organic solvent and surrounding a part of said first cooling coil means for enabling said solvent to be heated into organic vapor by heat energy of steam that goes out of said first turbine into said first cooling coil, a second generator for generating electricity, a second turbine rotated by the organic vapor produced in said second boiler for rotating second generator to generate electricity, a second cooling coil means for cooling the organic vapor passing through said second turbine into condensed solvent and guiding the condensed solvent back to said second boiler, and a cooling pond for circulating a cooling water or cooling air to cool down said second cooling coil.