KR102239301B1 - Floating marine structure with electric power generator - Google Patents

Abstract

A floating offshore structure is disclosed. The floating offshore structure according to the present invention removes nitrogen oxide contained in the exhaust gas of the waste heat recovery boiler of the power generation unit in a selective catalytic reduction reactor, and the reduction catalyst reactor receives ammonia stored in the ammonia tank and receives nitrogen oxide. Is removed by reducing it with nitrogen and moisture. In addition, a large amount of ammonia can be stored in the ammonia tank only when the ammonia in the ammonia tank is in a liquid state. At this time, since the ammonia in the ammonia tank is kept in a liquid state by using the cold heat of LNG (Liquefied Natural Gas) supplied from the LNG tank to the regasification unit, a separate cold source for maintaining the ammonia in the ammonia tank in a liquid state. ) Is not required. Therefore, there may be an effect of reducing the cost.

Description

Floating offshore structure with power generation system {FLOATING MARINE STRUCTURE WITH ELECTRIC POWER GENERATOR}

The present invention relates to a floating offshore structure having a power generation system capable of storing ammonia in a liquid state for removing nitrogen oxides using cold heat of LNG (Liquefied Natural Gas).

Today, as part of interest in the environment, interest in eco-friendly power generation systems is increasing, and as a kind of eco-friendly power generation system, there is a power generation system that uses natural gas as power generation fuel.

However, in order to build a power generation system using natural gas as power generation fuel on land, infrastructure such as an LNG tank and gas supply system is required. It is difficult to build the power generation system to be used.

In order to solve the above problems, a power generation system is installed on the hull equipped with a device for storing and regasifying gas, and a floating offshore structure that transmits power to its own use place and land use place after power generation in the hull is developed. It has become and is being used.

The power generation system has a waste heat recovery boiler that generates steam using high-temperature exhaust gas, and the exhaust gas flowing into the waste heat recovery boiler generates steam and then is discharged from the waste heat recovery boiler. However, since the exhaust gas flowing into the waste heat recovery boiler contains nitrogen oxides that cause environmental pollution, the exhaust gas must be discharged after removing the nitrogen oxides.

As a method of removing nitrogen oxides contained in exhaust gas, there is a selective catalytic reduction method in which nitrogen oxides are reduced to nitrogen and moisture using a catalyst. In the case of the selective catalytic reduction method, when ammonia is injected into a selective catalytic reduction (SCR) reactor, nitrogen oxides are reduced to nitrogen and moisture and removed.

One side of the waste heat recovery boiler is provided with an ammonia tank for storing ammonia and supplying ammonia to a reduction catalyst reactor installed inside the waste heat recovery boiler. At this time, ammonia must be stored in a liquid state to store a large amount of ammonia in the ammonia tank.

Conventionally, since a separate cold heat source must be provided in order to maintain the ammonia in the ammonia tank in a liquid state, there is a disadvantage in that the cost increases.

Prior art for removing nitric oxide using ammonia is disclosed in Korean Patent Laid-Open Publication No. 10-1998-0024189 (July 06, 1998).

An object of the present invention may be to provide a floating offshore structure capable of solving all the problems of the prior art as described above.

Another object of the present invention may be to provide a floating offshore structure that can reduce cost.

A floating offshore structure according to the present invention for achieving the above object includes: a hull; An LNG tank installed on the hull and storing LNG (Liquefied Natural Gas); A regasification unit installed on the hull, receiving and vaporizing LNG from the LNG tank; A power generation unit having a waste heat recovery boiler that is installed on the hull to generate steam from natural gas (NG) vaporized in the regasification unit, and receives exhaust gas generated during power generation to generate steam; In order to remove nitrogen oxides contained in the exhaust gas of the waste heat recovery boiler, an ammonia tank storing ammonia supplied to the selective catalytic reduction (SCR) reactor of the waste heat recovery boiler is included, and the ammonia in the ammonia tank is The liquid state can be maintained by the cooling and heat of LNG.

The floating offshore structure according to this embodiment removes nitrogen oxides contained in the exhaust gas of the waste heat recovery boiler of the power generation unit in a selective catalytic reduction reactor, and the reduction catalyst reactor receives ammonia stored in the ammonia tank and receives nitrogen. The oxide is removed by reducing it with nitrogen and moisture. In addition, a large amount of ammonia can be stored in the ammonia tank only when the ammonia in the ammonia tank is in a liquid state. At this time, since the ammonia in the ammonia tank is kept in a liquid state by using the cold heat of LNG (Liquefied Natural Gas) supplied from the LNG tank to the regasification unit, a separate cooling source for maintaining the ammonia in the ammonia tank in a liquid state. ) Is not required. Therefore, there may be an effect of reducing the cost.

1 is a view showing the configuration of a floating offshore structure according to an embodiment of the present invention.
Figure 2 is an enlarged view of the waste heat recovery boiler shown in Figure 1;
Figure 3 is a view showing the configuration of a floating offshore structure according to another embodiment of the present invention.

In the present specification, in adding reference numerals to elements of each drawing, it should be noted that, even though they are indicated on different drawings, the same elements are to have the same number as possible.

Meanwhile, the meaning of the terms described in the present specification should be understood as follows.

Singular expressions should be understood as including plural expressions unless clearly defined differently in context, and terms such as “first” and “second” are used to distinguish one element from other elements, The scope of rights should not be limited by these terms.

It is to be understood that terms such as "comprises" or "have" do not preclude the presence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

The term “at least one” is to be understood as including all possible combinations from one or more related items. For example, the meaning of “at least one of the first item, the second item, and the third item” is 2 of the first item, the second item, and the third item, as well as each It means a combination of all items that can be presented from more than one.

The term "and/or" is to be understood as including all possible combinations from one or more related items. For example, the meaning of “the first item, the second item and/or the third item” means two of the first item, the second item, or the third item as well as the first item, the second item, or the third item. It means a combination of all items that can be presented from the above.

When a component is referred to as being "connected or installed" to another component, it is to be understood that it may be directly connected or installed to the other component, but other components may exist in the middle. On the other hand, when a component is referred to as "directly connected or installed" to another component, it should be understood that the other component does not exist in the middle. On the other hand, other expressions describing the relationship between the constituent elements, that is, "between" and "directly between" or "adjacent to" and "directly adjacent to" should be interpreted as well.

Hereinafter, a floating offshore structure according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram showing the configuration of a floating offshore structure according to an embodiment of the present invention, and FIG. 2 is an enlarged view of the waste heat recovery boiler shown in FIG. 1.

As shown, the floating offshore structure according to this embodiment may include a hull 110, an LNG tank 120, a regasification unit 130, and a power generation unit 140.

The hull 110 may float on the surface by buoyancy, and the LNG tank 120 may be installed on the hull 110 to store LNG (Liquefied Natural Gas). The LNG tank 120 is preferably installed at the lower portion of the hull 110, and the LNG stored in the LNG tank 120 is in a liquid state of approximately -160°C or less.

The regasification unit 130 is installed in the hull 110, and receives LNG from the LNG tank 120 to vaporize the liquid LNG into a gaseous state, and the LNG vaporized in the regasification unit 130 is approximately room temperature ( It can have a temperature of 常溫). The regasification unit 130 may include a tank in which LNG is stored, a pump for discharging LNG from the tank, a carburetor for vaporizing LNG discharged from the tank, and the like.

The power generation unit 140 may be installed on the hull 110 and may generate power by using natural gas (NG) vaporized in the regasification unit 130 as power generation fuel. The power generation unit 140 will be described in detail.

The power generation unit 140 may include a gas turbine 151, a waste heat recovery boiler 160, a steam turbine 153, and a condenser 155.

The gas turbine 151 may be driven by combustion gas generated when the vaporized NG supplied from the regasification unit 130 is combusted, and generates electricity while the generator 151a is driven by the gas turbine 151. The combustion gas driving the gas turbine 151 is discharged to the outside of the gas turbine 151, and the exhaust gas discharged from the gas turbine 151 may be introduced into the waste heat recovery boiler 160.

The waste heat recovery boiler 160 generates steam using the exhaust gas discharged from the gas turbine 151, and the steam turbine 153 is driven by the steam discharged from the waste heat recovery boiler 160. Then, the steam turbine 153 generates power while driving another generator 153a.

The steam driving the steam turbine 153 is discharged and condensed in the condenser 155 and discharged, and the condensed water discharged from the condenser 155 may be re-inflowed into the waste heat recovery boiler 160.

The floating offshore structure according to the present embodiment burns vaporized NG, drives the gas turbine 151 using combustion gas generated during combustion of the vaporized NG, and drives the gas turbine 151 by the generator 151a. As it drives, it develops in the first order. Then, the waste heat recovery boiler 160 generates steam using the exhaust gas discharged from the gas turbine 151, the steam turbine 153 is driven by the steam generated by the waste heat recovery boiler 160, and the steam turbine The generator 153a generates secondary power by 153. Therefore, the power generation efficiency can be improved.

Most of the electricity generated by the power generation unit 140 is supplied to the land use, and the rest can be used in the floating offshore structure itself.

The hull 110 may be provided with a propulsion unit 190 for moving the hull 110, and the propulsion unit 190 may include a power device for rotating the propeller and a waste heat recovery boiler. The power device may rotate the propeller while being driven by combustion gas generated during combustion of a propulsion fuel such as gas or oil, and the waste heat recovery boiler may use the exhaust gas discharged after driving the power device to generate steam. Can be generated.

The waste heat recovery boiler 160 will be described with reference to FIG. 2.

The waste heat recovery boiler 160 may include a main body 161, and on one side and the other side of the main body 161, an inlet 161a through which exhaust gas discharged from the gas turbine 151 is introduced and a chimney discharged Each of the discharge parts 161b provided in such a manner may be formed.

Inside the body 161, an economizer 163a for heating water with residual heat of the exhaust gas introduced into the body 161 may be installed, and between the inlet 161a and the economizer 163a An evaporator 163b for vaporizing water delivered from the economizer 163a may be installed inside the body 161 of the body 161, and an evaporator inside the body 161 between the inlet 161a and the evaporator 163b A superheater 163c for generating superheated steam by heating the steam transmitted from (163b) may be installed.

The steam turbine 153 may be driven by the superheated steam generated by the superheater 163c to generate power.

At this time, at one side of the main body 161, a water tank/deaerator 165 for removing oxygen dissolved in water while storing water may be installed, and the water of the water tank/deaerator 165 is an economizer. Can be supplied as (163a). In addition, water heated by the economizer 163a may flow into the evaporator 163b through the drum 163d.

Based on the direction shown in FIG. 2, the exhaust gas may be introduced to the left side of the main body 161 and discharged to the right side, and water may be introduced from the right side of the main body 161 and discharged to the left side.

In addition, the economizer 163a, the evaporator 163b, the superheater 163c, and the drum 163d described above may be installed on the inlet 161a side and the outlet 161b, respectively. At this time, the economizer 163a, the evaporator 163b, the superheater 163c, and the drum 163d installed inside the main body 161 on the inlet 161a side are the high-pressure region 163, and The economizer, the evaporator, the superheater, and the drum installed inside the 161 are a low pressure region 164.

The exhaust gas flowing into the body 161 through the inlet 161a may contain nitrogen oxides that cause environmental pollution. Therefore, after removing nitrogen oxides contained in the exhaust gas flowing into the main body 161, the exhaust gas must be discharged to the discharge unit 161b.

The waste heat recovery boiler 160 according to an embodiment of the present invention may remove nitrogen oxides contained in exhaust gas using a selective catalytic reduction (SCR) reactor 167. Since the optimum denitrification efficiency occurs when the temperature of the exhaust gas is 300 to 400°C, the SCR reactor 167 is between the superheater 163c and the evaporator 163b having a temperature range of 300 to 400°C. Can be installed.

The SCR reactor 167 uses a catalyst and acts with ammonia supplied separately to reduce nitrogen oxides contained in the exhaust gas into nitrogen and moisture. In order to supply ammonia to the SCR reactor 167, an ammonia tank 171 in which ammonia is stored may be installed at one side of the waste heat recovery boiler 160.

Ammonia supplied to the SCR reactor 167 is in a liquid state. However, when the ammonia stored in the ammonia tank 171 can be maintained in a liquid state, a large amount of ammonia can be stored in the ammonia tank 171.

The floating offshore structure according to an embodiment of the present invention may maintain ammonia in the ammonia tank 171 in a liquid state by using cold heat of LNG.

In order to maintain the ammonia in the ammonia tank 171 in a liquid state with the cold heat of LNG, the LNG pipeline 173 for supplying LNG from the LNG tank 120 to the regasification unit 130 is heat-exchanged with the ammonia tank 171 I can.

That is, by extending the LNG pipeline 173 installed between the LNG tank 120 and the regasification unit 130 to supply LNG from the LNG tank 120 to the regasification unit 130, heat exchange of the ammonia tank 171 can be performed. have. It is natural that the meaning that the LNG pipe 173 and the ammonia tank 171 heat exchange means that the LNG of the LNG pipe 173 and the ammonia in the ammonia tank 171 heat exchange. Then, the ammonia in the ammonia tank 171 is cooled by LNG of about -160° C. or less to maintain a liquid state.

The floating offshore structure according to an embodiment of the present invention removes nitrogen oxide contained in the exhaust gas of the waste heat recovery boiler 160 of the power generation unit 140 from the SCR reactor 167, and the SCR reactor 167 is ammonia. Ammonia stored in the tank 171 is supplied and nitrogen oxides are reduced to nitrogen and moisture to be removed. In addition, a large amount of ammonia can be stored in the ammonia tank 171 only when the ammonia in the ammonia tank 171 is in a liquid state. At this time, since the ammonia in the ammonia tank 171 is kept in a liquid state by using the cold heat of LNG, there is no need for a separate cold source for maintaining the ammonia in the ammonia tank 171 in a liquid state. Thus, the cost is reduced.

3 is a diagram showing a configuration of a floating offshore structure according to another embodiment of the present invention, and only differences from FIG. 1 are described.

As shown, the ammonia tank 171 may indirectly exchange heat with LNG.

In detail, an LNG pipeline 173 for supplying LNG from the LNG tank 120 to the regasification unit 130 and a heat exchanger 181 for heat exchange at one side may be provided. In addition, one side heat exchange with the other side of the heat exchanger 181, the other side heat exchange with the ammonia tank 171, and a cooling medium circulation pipe 183 through which the cooling medium flows and circulates therein may be provided.

Then, since the LNG pipe 173 and the ammonia tank 171 exchange heat with each other through the heat exchanger 181 and the cooling medium circulation pipe 183, the ammonia in the ammonia tank 171 is maintained in a liquid state.

It is natural that the LNG pipe 173 and the heat exchanger 181 heat exchange means that the LNG of the LNG pipe 173 and the heat exchanger 181 heat exchange, and the heat exchanger 181 and the cooling medium circulation pipe 183 ) Means that the heat exchanger 181 and the cooling medium of the cooling medium circulation duct 183 exchange heat, and the cooling medium circulation duct 183 and the ammonia tank 171 heat exchange. It is natural that the cooling medium in the medium circulation pipe 183 and the ammonia in the ammonia tank 171 heat exchange.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications and changes are possible within the scope of the technical spirit of the present invention. It will be obvious to those who have the knowledge of. Therefore, the scope of the present invention is indicated by the claims to be described later, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

120: LNG tank
130: regasification unit
140: development department
160: waste heat recovery boiler
167: reduction catalyst reactor
171: ammonia tank

Claims (4)

hull;
An LNG tank installed on the hull and storing LNG (Liquefied Natural Gas);
A regasification unit installed on the hull, receiving and vaporizing LNG from the LNG tank;
A power generation unit having a waste heat recovery boiler installed on the hull to generate steam from natural gas (NG) vaporized by the regasification unit as fuel, and receiving exhaust gas generated during power generation to generate steam;
A reduction catalyst (SCR: Selective Catalytic Reduction) reactor for reducing nitrogen oxides contained in the exhaust gas of the waste heat recovery boiler into nitrogen and moisture; And
It includes an ammonia tank for storing ammonia supplied to the reduction catalyst reactor in a liquid state,
The ammonia in the ammonia tank is cooled by cold heat of LNG to maintain a liquid state. The method of claim 1,
An LNG pipeline for supplying LNG from the LNG tank to the regasification unit is installed,
A floating offshore structure, characterized in that heat exchange between the LNG pipe and the ammonia tank. The method of claim 1,
An LNG pipeline for supplying LNG from the LNG tank to the regasification unit is installed,
A heat exchanger having one side of exchanging heat with the LNG pipe;
A floating offshore structure, characterized in that it further comprises a cooling medium circulation pipe through which the cooling medium circulates, and one side heat exchanges with the other side of the heat exchanger and the other side heat exchange with the ammonia tank. The method of claim 1, wherein the waste heat recovery boiler,
A main body provided with an inlet portion;
An economizer that heats water with residual heat of exhaust gas;
An evaporator provided inside the main body between the inlet and the economizer and vaporizing the water transferred from the economizer; And
And a superheater provided inside the body between the inlet and the evaporator to generate superheated steam by heating the steam transmitted from the evaporator,
The reduction catalyst reactor,
A floating offshore structure, characterized in that it is provided between the superheater and the evaporator having a temperature of the exhaust gas in a temperature range of 300 to 400°C.

Images