KR20160088681A - Complex power plant, waste heat recovery system and method using organic refrigerant - Google Patents

Abstract

The present invention relates to a waste heat recovery system using an organic refrigerant, which performs the power generation of a gas turbine, the power generation of a steam turbine using the waste heat discarded in the gas turbine, and organic Rankine cycle power generation using the medium and low temperature heat of the waste steam in the steam turbine, and increases energy production by lowering the condensing temperature of an organic solvent used for organic Rankine power generation using the cold energy of LNG discarded in an LNG evaporating process for supplying evaporated LNG to a required place on the land.

Description

TECHNICAL FIELD [0001] The present invention relates to a combined power generation plant, a waste heat recovery system for the combined power generation plant, and a waste heat recovery method using organic refrigerant. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a waste heat recovery system using an organic refrigerant, and more particularly, to an organic lan- guine power generation system using steam generated from a steam turbine, A waste heat recovery system for the combined power generation plant, and a waste heat recovery method using an organic refrigerant. The present invention relates to a waste heat recovery method using an organic refrigerant, and more particularly, to a combined power generation plant capable of increasing the amount of power generation by lowering the condensation temperature of an organic solvent used for organic Rankine power generation.

In recent years, there has been an increasing interest in the development of natural gas as a demand for environmentally friendly power generation. In particular, as combined-cycle power generation technology that recovers waste heat to drive a steam turbine is emerging, the demand for gas power generation is steadily increasing due to an increase in efficiency of gas power generation and stabilization of gas price.

In emerging economies where power supply is not smooth, interest in gas power generation is growing. Due to the nature of gas power generation, gas infrastructure such as a gas reservoir must be equipped on the land. Especially, in the case of Southeast Asian countries composed of several islands, it was difficult to generate large capacity gas.

In order to solve this problem, a float storage re-gasification unit (FSRU) floating water gas storage and regeneration facility line has emerged, and by using such a sea gas storage regenerating facility line, .

However, the development using FSRU causes the installation of FSRU at sea and the dual burden of constructing a power plant on the land. In other words, there is a disadvantage that it requires not only the FSRU but also the construction cost and the time required for the construction of the land power plant.

To overcome these drawbacks, a new concept floating power combined-cycle power plant with a power plant on a floating structure such as a barge has been actively researched and developed.

The conventional floating combined cycle power plant includes a gas turbine that generates electricity by using LNG stored in an LNG storage tank as fuel, a waste heat recovery device that collects waste heat recovered from the gas turbine to produce steam, And a steam turbine for generating electric power by the pressure of the steam.

However, the conventional waste heat recovery apparatus in a conventional combined power generation plant can obtain an appropriate vapor pressure at a high temperature of 170 DEG C or higher, and thus waste heat of medium and low temperature, which is lower than that, can not be recovered and is discarded.

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In order to solve the above-mentioned problems, the present invention provides a steam turbine generator for a steam turbine, which uses power generated from a gas turbine, waste heat from the gas turbine, and steam generated from the steam turbine, A combined power plant capable of increasing the power generation by lowering the condensation temperature of the organic solvent used in the organic Rankine power generation by using the cold heat of the LNG that is discarded in the vaporization process of the LNG to supply the waste heat A recovery system, and a waste heat recovery method using an organic refrigerant.

In order to achieve the above-mentioned object, the present invention provides a gas turbine comprising: a gas turbine that generates electric power by using LNG stored in an LNG storage tank as fuel; A waste heat recovery device for recovering waste heat from the gas turbine to produce steam; A steam turbine for generating electric power by the pressure of the steam produced by the waste heat recovering device; An organic refrigerant evaporator for evaporating organic refrigerant using waste heat of steam discarded in the steam turbine; An organic refrigerant turbine for generating electric power by a vapor pressure of the organic refrigerant by the organic refrigerant evaporator; An organic refrigerant condenser for condensing the organic refrigerant through the organic refrigerant turbine by using the cold heat of LNG; And an NG turbine that generates electric power using the expansion pressure of NG gasified from the organic refrigerant condenser.

A steam condenser for condensing the steam passing through the steam turbine and a pump for circulating the condensed condensed water to the waste heat recovering device may be installed in the first cycle line circulating from the waste heat recovering device to the steam turbine.

A pump for circulating the condensed organic refrigerant to the organic refrigerant evaporator may be installed in the second cycle line circulating from the organic refrigerant evaporator to the organic refrigerant condenser.

When the NG turbine is driven using the NG expansion pressure, the LNG is transferred to the gas supply pipe by the LNG pump of the LNG storage tank, and the LNG transferred to the gas supply pipe is heated by heat exchange with the organic refrigerant condenser Is vaporized via the LNG evaporator, and can be configured to drive the NG turbine using the expansion pressure of the vaporized NG.

The NG via the NG turbine can be configured to supply to the onshore consumer.

The cooling water line for cooling the gas turbine is supplied to the cooling water inlet of the gas turbine and the heated high temperature cooling water taken from the gas turbine is cooled to the seawater temperature by heat exchange with the LNG evaporator, Line outlet.

According to another aspect of the present invention, there is provided a gas turbine comprising: a gas turbine for generating electric power using LNG as fuel; a waste heat recovery device for recovering waste heat recovered from the gas turbine to produce steam; Turbine, and an organic Rankine power generation unit for generating electric power using waste heat discarded in the steam turbine. The LNG storage tank is configured to vaporize LNG in the LNG storage tank and supply it to a demand place on the land. In the LNG storage tank, And the condensing temperature of the organic refrigerant circulating in the organic Rankine generator unit is lowered by using cold heat to increase the amount of electric power generated.

The organic cold-cool electricity generating unit includes an organic refrigerant evaporator for evaporating organic refrigerant by using waste heat of steam discarded in the steam turbine; An organic refrigerant turbine for generating electric power by a vapor pressure of the organic refrigerant by the organic refrigerant evaporator; And an organic refrigerant condenser for condensing the organic refrigerant through the organic refrigerant turbine by using the cold heat of the LNG.

The cooling water line for cooling the gas turbine is supplied to the cooling water inlet of the gas turbine and the heated high temperature cooling water taken from the gas turbine is cooled to the seawater temperature by heat exchange with the LNG evaporator, Can be drained to the line outlet.

The present invention relates to a steam generator for generating electricity from a steam turbine using waste heat from a gas turbine, an organic quasi-thermal energy generator for generating steam from the steam turbine, The present invention provides a waste heat recovery method capable of increasing the efficiency of the organic Rankine power generation by lowering the condensation temperature of the organic solvent used in the organic Rankine power generation by using the LNG of the LNG that is discarded during the LNG vaporization process.

In the case where the LNG is vaporized and supplied to a demand site on the land, the LNG can be cooled and generated using the LNG that is discarded in the LNG vaporization process.

As described above, according to the present invention, it is possible to perform the organic Rankine power generation using the moderate and low-temperature heat amount of the steam discarded in the steam turbine. In the vaporization process of the LNG for supplying the LNG to the demand site on the land, It is possible to increase the electric power production by lowering the condensation temperature of the organic solvent used in the organic Rankine power generation.

1 is a view showing a TS diagram of the present invention;
2 is a side view showing a combined-cycle power plant according to the present invention;
3 is a view showing a waste heat recovering system of a combined power generation plant according to the present invention

Hereinafter, a combined power generation plant, a waste heat recovery system for the combined power generation plant, and a waste heat recovery method using organic refrigerant according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a method for recovering waste heat using an organic refrigerant, comprising the steps of: generating a steam turbine using waste heat from a gas turbine and generating waste gas from the gas turbine; and performing an organic Rankine power generation using steam, In the vaporization process of the LNG for vaporizing and supplying to the demand site on the land, the cooling rate of the organic solvent used for the organic Rankine power generation can be lowered by using the LNG cold energy to be discarded, thereby increasing the efficiency of the organic Rankine power generation. Examples of the organic refrigerant include R227ea, R236fa, R245fa, and the like.

FIG. 1 shows a TS diagram for explaining the basic principle of the present invention. In the cooling method using seawater as in the prior art, the cycle proceeds from 1 to> 2-> 3 -> 4 '-> 1 -> 2 On the other hand, in the cooling method using LNG having a temperature lower than that of seawater according to the present invention, the cycle proceeds from 1 to> 2> 3> '4' '> 1'>> 2, . Therefore, it can be confirmed from the formula of power generation amount = thermal headloss x power generation efficiency that the present invention can significantly increase power generation amount.

In the waste heat recovery method of the present invention, when the LNG is vaporized and supplied to a customer onshore, the LNG can be cooled and cooled using the LNG that is discarded in the LNG vaporization process.

Further, at the inlet of the cooling water line of the gas turbine, seawater for cooling the gas turbine is introduced into the cooling water, and the heated high temperature cooling water is cooled by the heat exchange with the LNG evaporator by taking the heat from the gas turbine And can be discharged to the outlet of the cooling water line, thereby effectively preventing marine pollution due to discharge of cooling water.

Hereinafter, a combined power generation plant and a waste heat recovery system according to the present invention will be described with reference to the drawings.

FIG. 2 is a side view showing a combined power generation plant according to the present invention, and FIG. 3 is a view showing a waste heat recovery system of a combined power generation plant according to the present invention.

As shown in FIGS. 2 and 3, the combined power generation plant 100 of the present invention includes a floating structure floating on the sea, an LNG storage tank stored in the floating structure, and an LNG storage tank And a power plant for generating electric power.

The power generation plant of the present invention includes a gas turbine 110 for generating electricity using LNG stored in an LNG storage tank as a fuel, a waste heat recovery device 120 for recovering waste heat, which is discarded in the gas turbine 110, And a steam turbine 130 for generating electric power by the pressure of the steam produced by the waste heat recovering device 120.

The gas turbine 110 includes a combustor 111 for combusting the fuel gas vaporized from the LNG in the LNG storage tank, a compressor 112 for supplying compressed air of low temperature and high density to the combustor 111 for combustion of the fuel gas, A turbine 113 that generates power while rotating using the force generated by the combustion of the fuel gas in the combustor 111 and a generator 114 that generates power using the rotational force of the turbine 113 .

The steam turbine 130 includes a turbine 131 generating power by rotating using the pressure of the steam generated by the waste heat recovering device 120 and a generator 132 generating power using the rotational force of the turbine 131 ).

The first cycle line L 1 circulating from the waste heat recovery apparatus 120 to the steam turbine 130 is provided with a steam condenser 121 for condensing steam passing through the steam turbine 130, And a pump 122 for circulating the waste heat recovered by the waste heat recovery apparatus 120 may be installed.

The waste heat recovery apparatus 120 rotates the turbine 113 and recovers the waste heat to generate condensed water circulating through the first cycle line L 1 to generate steam.

The combined power generation plant 100 of the present invention performs the organic Rankine power generation using the moderate and low calorific value of steam to be discarded in the steam turbine 130. The LNG And a waste heat recovery system that can reduce the condensation temperature of the organic solvent used in the organic Rankine power generation to increase the organic Rankine power generation efficiency, that is, the power production amount.

Hereinafter, a waste heat recovery system of a combined power generation plant will be described.

The waste heat recovery system of a combined power generation plant according to the present invention includes an organic cold power generation unit.

The organic cold-free electricity generating unit includes an organic refrigerant evaporator 140 for evaporating the organic refrigerant by using waste heat of steam discarded in the steam turbine 130, and an organic refrigerant evaporator 140 for generating electric power by the vapor pressure of the organic refrigerant An organic refrigerant turbine 150, and an organic refrigerant condenser 160 for condensing the organic refrigerant through the organic refrigerant turbine 150 using the cold heat of the LNG.

The organic refrigerant turbine 150 includes a turbine 151 generating power by rotating using the evaporation pressure of the organic refrigerant evaporated in the organic refrigerant evaporator 140, Generator 152, as shown in FIG.

A pump 161 for circulating the condensed organic refrigerant to the organic refrigerant evaporator 140 is installed in the second cycle line L 2 circulating from the organic refrigerant evaporator 140 to the organic refrigerant condenser 160 .

The LNG is delivered to the gas supply line L 4 by the LNG pump P of the LNG storage tank when the NG turbine 170 is driven using the NG expansion pressure and is transferred to the gas supply line L 4 The LNG may be heated by heat exchange with the organic refrigerant condenser 160 and then vaporized via the LNG evaporator 180 and may be configured to drive the NG turbine 170 using the expanded pressure of the NG gas.

The NG turbine 170 includes a turbine 171 that generates power by rotating using the evaporation pressure of the organic refrigerant evaporated in the organic refrigerant evaporator 140 and a generator 171 that generates power using the rotational force of the turbine 111. [ Lt; / RTI >

NG via the NG turbine 170 can be configured to supply to the onshore demand site.

At the inlet of the cooling water line L 3 of the gas turbine 110, seawater for cooling the gas turbine 110 flows into the cooling water, and heat is taken from the gas turbine 110, May be cooled to the seawater temperature by heat exchange with the LNG evaporator 180 and may be discharged to the outlet of the cooling water line (L 3).

The operation of the combined power generation plant and the waste heat recovery system of the combined power generation plant according to the present invention constructed as described above will be described as follows.

The LNG stored in the LNG storage tank is vaporized to supply the fuel gas to the gas turbine 110, and the gas turbine 110 generates electric power using the supplied fuel gas. The operation of the gas turbine 110 will be briefly described below. That is, in the compressor 112, compressed air having a low temperature and a high density is supplied to the combustor 111, the mixed gas of the compressed air and the fuel gas is combusted in the combustor 111 and the turbine 113 is rotated by the generated gas pressure And the generator 114 generates electric power using the rotational force of the turbine 113. [

The waste heat recovery apparatus 120 rotates the turbine 113 and recovers the waste heat to generate condensed water circulating through the first cycle line L 1 to generate steam.

The steam turbine 130 performs primary power generation using steam generated by the waste heat recovery apparatus 120. The operation of the steam turbine 130 will be briefly described below. That is, the steam generated in the waste heat recovery apparatus 120 is used to rotate the turbine 131 to generate power, and the generator 132 generates power using the rotational force of the turbine 131. The turbine 131 is rotated and the steam to be discarded is condensed while passing through the steam condenser 121 and then supplied to the waste heat recovery apparatus 120 by the pump 122.

In the second cycle line L 2 circulating from the organic refrigerant evaporator 140 to the organic refrigerant condenser 160, the pump 161 circulates the organic refrigerant, and the organic refrigerant evaporator 140 is connected to the steam turbine 130 to evaporate the organic refrigerant. The organic refrigerant turbine 150 produces electric power by the vapor pressure of the organic refrigerant. The organic refrigerant condenser condenses the organic refrigerant by using the cold heat of the LNG.

The LNG is transferred to the gas supply line L 4 by the LNG pump P of the LNG storage tank and the LNG transferred to the gas supply line L 4 is heat exchanged with the organic refrigerant condenser 160, And then is vaporized via the LNG evaporator 180. [

The NG turbine 170 produces power using the expansion pressure of the vaporized NG. That is, the NG generates the power by rotating the turbine 171, and the generator 172 generates electric power using the rotational force of the turbine 171. The NG that has passed through the turbine 171 is supplied to a demand place on the land.

As described above, according to the present invention, it is possible to utilize the cold heat of the LNG that is discarded in the vaporization process of the LNG for supplying the steam to the customer on the ground by vaporizing the LNG, Thereby lowering the condensation temperature of the organic solvent used in the organic Rankine power generation, thereby increasing the power generation amount.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Various modifications and variations are possible within the scope of equivalents.

110: Gas turbine
111: Combustor
112: compressor
113: Turbine
114: generator
120: waste heat recovery device
121: Steam condenser
122: pump
130: Steam turbine
131: Turbine
132: generator
140: organic refrigerant evaporator
150: Organic refrigerant turbine
151: Turbine
152: generator
160: Organic refrigerant condenser
161: Pump
170: NG turbine
171: Turbine
172: generator
180: LNG evaporator
L 1: first cycle line
L 2: second cycle line
L 3: Cooling water line
L 4: gas supply line
P: LNG pump

Claims (11)

A gas turbine that produces electricity using LNG stored in an LNG storage tank as fuel;
A waste heat recovery device for recovering waste heat from the gas turbine to produce steam;
A steam turbine for generating electric power by the pressure of the steam produced by the waste heat recovering device;
An organic refrigerant evaporator for evaporating organic refrigerant using waste heat of steam discarded in the steam turbine;
An organic refrigerant turbine for generating electric power by a vapor pressure of the organic refrigerant by the organic refrigerant evaporator;
An organic refrigerant condenser for condensing the organic refrigerant through the organic refrigerant turbine by using the cold heat of LNG; And
And an NG turbine for generating electric power using the expansion pressure of NG gasified from the organic refrigerant condenser. The method according to claim 1,
A steam condenser for condensing the steam passing through the steam turbine and a pump for circulating the condensed condensed water to the waste heat recovering device are installed in a first cycle line circulating from the waste heat recovering device to the steam turbine. Waste heat recovery system of power plant. The method according to claim 1,
And a pump for circulating the condensed organic refrigerant to the organic refrigerant evaporator is installed in the second cycle line circulating from the organic refrigerant evaporator to the organic refrigerant condenser. The method according to claim 1,
When the NG turbine is driven using the NG expansion pressure, the LNG is transferred to the gas supply pipe by the LNG pump of the LNG storage tank, and the LNG transferred to the gas supply pipe is heated by heat exchange with the organic refrigerant condenser LNG vaporizer, and drives the NG turbine using the expansion pressure of the NG gasified gas. The method of claim 4,
And the NG via the NG turbine is supplied to a demand site on the land. The method of claim 4,
The cooling water line for cooling the gas turbine is supplied to the cooling water inlet of the gas turbine and the heated high temperature cooling water taken from the gas turbine is cooled to the seawater temperature by heat exchange with the LNG evaporator, Line outlet of the combined-cycle power plant. A waste heat recovery device for recovering waste heat recovered from the gas turbine to produce steam, a steam turbine for generating electric power by steam pressure produced by the waste heat recovery device, And an organic Rankine generator unit for generating electric power by using waste heat discarded in the turbine,
Characterized in that the LNG storage tank is vaporized and supplied to a demand place on the land, and the condensation temperature of the organic refrigerant circulating in the organic Rankine power generation unit is lowered by using the LNG cold energy, which is discarded in the LNG vaporization process, Combined power plant. The method of claim 7,
The organic cold-
An organic refrigerant evaporator for evaporating organic refrigerant using waste heat of steam discarded in the steam turbine;
An organic refrigerant turbine for generating electric power by a vapor pressure of the organic refrigerant by the organic refrigerant evaporator; And
And an organic refrigerant condenser for condensing the organic refrigerant through the organic refrigerant turbine by using the cold heat of the LNG. The method of claim 8,
The cooling water line for cooling the gas turbine is supplied to the cooling water inlet of the gas turbine and the heated high temperature cooling water taken from the gas turbine is cooled to the seawater temperature by heat exchange with the LNG evaporator, And the water is drained to an outlet of the line. The present invention relates to a steam turbine and a steam turbine, and more particularly, to a steam turbine for a steam turbine, Wherein the cooling efficiency of the organic Rankine power generation is increased by lowering the condensation temperature of the organic solvent used in the organic Rankine power generation by using the cold heat of the LNG to be discarded during the vaporization process of the organic Rankine power. The method of claim 10,
Wherein the LNG is vaporized and supplied to a demand site on the land, and the LNG is cooled by the LNG vaporized during the LNG vaporization process.

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