KR20240102537A - Carbon Dioxide Emission Reduction System for Vessel - Google Patents

Abstract

The present invention relates to a carbon dioxide emission reduction system for ships that can reduce carbon dioxide emissions in the exhaust gas of marine engines.
The carbon dioxide emission reduction system according to the present invention includes an engine that uses hydrocarbon-based liquefied gas or a mixed gas of hydrocarbon-based liquefied gas and hydrogen as fuel; a carbon dioxide reformer that generates hydrogen by reforming carbon dioxide in the exhaust gas discharged from the engine; A fuel supply device that supplies liquefied gas fuel to the engine; and a hydrogen supply line for joining the hydrogen generated in the carbon dioxide reformer to the gaseous fuel flow supplied from the fuel supply device to the engine.

Description

Carbon Dioxide Emission Reduction System for Vessel}

The present invention relates to a carbon dioxide emission reduction system for ships that can reduce carbon dioxide emissions in the exhaust gas of marine engines.

The existing economic system is based on carbon and is highly dependent on fossil fuels as an energy source. However, fossil fuel reserves are limited and are expected to be depleted in the near future, and carbon dioxide (CO ₂ ) generated during combustion is a representative greenhouse gas. It is pointed out as the main cause of global warming and climate change and is subject to international emissions regulations.

In particular, recently, an international consensus has been formed on the seriousness of global warming and climate change problems, and efforts are being made to reduce greenhouse gas emissions around the world. As the 1997 Kyoto Protocol, which included obligations for developed countries to reduce greenhouse gases, expires in 2020, the Paris Climate Change Agreement (Paris Climate Change) was adopted at the 21st United Nations Framework Convention on Climate Change held in Paris, France in December 2015 and came into effect in November 2016. The 195 parties that participated in the agreement (Change Accord) are making various efforts aimed at reducing greenhouse gases.

Along with this global trend, interest in new energy such as hydrogen and renewable energy (or renewable energy) such as wind power, solar power, solar heat, bioenergy, tidal power, and geothermal heat is increasing as a pollution-free energy that can replace fossil fuels, and various technologies are growing. Development is taking place.

Among them, hydrogen energy is environmentally friendly and has high energy density, so it can be used as a fuel for automobile power sources and fuel cells for portable electronic devices. The price of fuel cells that use hydrogen as fuel is decreasing every year, making it an ideal energy source for the future. As the era of hydrogen energy is receiving attention, the era of hydrogen energy is advancing, and demand for hydrogen is also increasing every year.

Meanwhile, as each country's interest in greenhouse gas and air pollutant emissions increases and international environmental regulation standards are rapidly strengthened, research on the development of eco-friendly marine fuel technology and eco-friendly energy transportation technology is also being actively conducted on ships.

IMO (International Maritime Organization), a UN specialized organization established to internationally unify shipping routes, traffic rules, port facilities, etc., also plans to reduce greenhouse gases by 50% in 2050 compared to 2008 and reduce greenhouse gases by 100% by 2100. % reduction (GHG Zero Emission) is proposed as the goal, and regulations in each country and region are expected to be strengthened accordingly.

According to EEDI (Energy Efficiency Design Index), a mandatory carbon dioxide reduction regulation applied by IMO to new ships, the initial EEDI announcement called for a 10% reduction in carbon dioxide emissions in 2015 based on carbon dioxide emissions from 2013 to 2015. EEDI Phase 1 was applied, and it was planned to apply Phase 3 in 2025 by strengthening it by one stage every 5 years. However, for LPG carriers, EEDI Phase 3 was applied early from 2022, two years after the application of EEDI Phase 2. It is being done. As regulations on carbon dioxide emissions from ships are rapidly being strengthened, it may be difficult to achieve carbon dioxide emissions regulations in the future by using only LNG or LPG as fuel.

Accordingly, various research is being conducted on eco-friendly marine fuels that can reduce carbon dioxide emissions, and further on marine fuels for complete decarbonization. In particular, technologies for ships that can use ammonia, hydrogen, etc. as fuel are being actively researched and developed. there is.

Hydrogen is a non-toxic, colorless, and odorless gas and is the most abundant element in the universe. However, on Earth, hydrogen rarely exists alone. It exists in the form of compounds such as water and natural gas, so it must be separated from these substances. In order to use hydrogen energy widely and efficiently, an economical and simple hydrogen production technology is first needed.

The purpose of the present invention is to provide a carbon dioxide emission reduction system for ships that can reduce carbon dioxide emissions in exhaust gas by using hydrogen, which is attracting attention as a future energy source, as engine fuel.

According to one aspect of the present invention for achieving the above-described object, an engine using a hydrocarbon-based liquefied gas or a mixed gas of hydrocarbon-based liquefied gas and hydrogen as fuel; a carbon dioxide reformer that generates hydrogen by reforming carbon dioxide in the exhaust gas discharged from the engine; A fuel supply device that supplies liquefied gas fuel to the engine; And a hydrogen supply line that joins the hydrogen generated in the carbon dioxide reformer to the gaseous fuel flow supplied from the fuel supply device to the engine. A carbon dioxide emission reduction system including a is provided.

Preferably, it may further include a reformed gas supply line that supplies liquefied gas from the fuel supply device to the carbon dioxide reformer.

Preferably, hydrogen transferred from the carbon dioxide reformer through the hydrogen supply line may be mixed with carbon monoxide.

Preferably, it may further include a mixer for mixing gaseous fuel supplied to the engine from the fuel supply device and hydrogen transferred through the hydrogen supply line and supplying the mixture to the engine.

Preferably, the fuel supply device includes: a storage tank for storing the liquefied gas; a compressor for compressing the boil-off gas generated in the storage tank to the pressure required by the engine; A supply pump that pressurizes the liquefied gas stored in the storage tank to the pressure required by the engine; And it may include a vaporizer that vaporizes the liquefied gas pressurized by the supply pump.

According to another aspect of the present invention for achieving the above-described object, a ship including the carbon dioxide emission reduction system is provided.

The ship's carbon dioxide emission reduction system according to the present invention can prevent carbon dioxide from being emitted into the atmosphere by producing hydrogen by reforming carbon dioxide contained in the exhaust gas of an engine that uses hydrocarbon-based liquefied gas as fuel in the ship.

In addition, the amount of carbon dioxide contained in the exhaust gas from the engine can be reduced by generating hydrogen using carbon dioxide in the exhaust gas and co-combusting the generated hydrogen with hydrocarbon-based liquefied gas fuel as fuel for the engine.

Additionally, by generating hydrogen using carbon dioxide in exhaust gas, operating costs (OPEX) can be reduced in supplying hydrogen co-firing fuel.

Figure 1 is a schematic diagram briefly illustrating a ship's carbon dioxide emission reduction system according to an embodiment of the present invention.

In order to fully understand the operational advantages of the present invention and the objectives achieved by practicing the present invention, reference should be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the structure and operation of a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Here, in adding reference numerals to components in each drawing, it should be noted that identical components are indicated with the same reference numerals as much as possible, even if they are shown in different drawings. Additionally, the following examples may be modified into various other forms, and the scope of the present invention is not limited to the following examples.

In the embodiments of the present invention described later, the ship may adopt an engine that uses hydrocarbon-based liquefied gas as fuel or an engine capable of co-firing hydrocarbon-based liquefied gas and hydrogen.

Additionally, the engine may be a dual-fuel engine that can selectively use hydrocarbon-based liquefied gas and fuel oil as fuel.

Here, the liquefied gas is a hydrocarbon-based liquefied gas such as LNG (Liquefied Natural Gas), LEG (Liquefied Ethane Gas), LPG (Liquefied Petroleum Gas), Liquefied Ethylene Gas, and Liquefied Propylene Gas. It can be. In this specification, the liquefied gas fuel will be described by taking LNG as an example.

In addition, ships herein include ships with self-propulsion capabilities such as LNG carriers, liquefied hydrogen carriers, and LNG RVs (Regasification Vessels), as well as FPSOs (Floating Production Storage Offloading) and FSRUs (Floating Storage Regasification Units). This may also include offshore structures that do not have propulsion capabilities but are floating in the sea.

Hereinafter, with reference to FIG. 1, a ship's carbon dioxide emission reduction system according to an embodiment of the present invention will be described.

The ship's carbon dioxide emission reduction system according to the present invention provides an engine 200 that uses natural gas or a mixed gas of natural gas and hydrogen as fuel for the engine, and adjusts and supplies LNG to the conditions required by the engine 200. It includes a fuel supply device 100 that generates hydrogen by reforming carbon dioxide (CO ₂ ) in the exhaust gas generated from the engine 200.

The engine 200 of this embodiment may include at least one of a high-pressure engine that uses high-pressure compressed gas as fuel and a low-pressure engine that uses low-pressure compressed gas as fuel.

The high-pressure engine of this embodiment may be a dual-fuel engine as a propulsion engine for a ship. For example, the high-pressure engine may be a MAN Electronic Gas Injection (ME-GI) engine or an eXtra long stroke Dual Fuel (X-DF) engine. The ME-GI engine is a 2-stroke engine that adopts a diesel cycle and is a high-pressure injection engine that requires a fuel pressure condition of about 150 to 300 bar for gas fuel. The X-DF engine is a 2-stroke engine that adopts the Otto cycle and is a medium pressure injection engine that requires fuel pressure conditions of approximately 12 to 18 bar. In this embodiment, the high-pressure engine will be described by taking the ME-GI engine as an example.

Additionally, the low-pressure engine of this embodiment may be a dual-fuel engine as a ship's power generation engine. For example, the low-pressure engine may be a Dual Fuel Diesel Electric (DFDE) or a Dual Fuel Diesel Generator (DFDG). DFDE is a 4-stroke engine that adopts the Otto cycle and is a low-pressure injection engine that requires a fuel pressure condition of about 4 to 8 bar for gas fuel. In this embodiment, the low-pressure engine will be described by taking a DFDE as an example.

The engine 200 of this embodiment may use LNG boil-off gas, forced vaporization gas obtained by forcibly vaporizing LNG, or a mixed gas in which hydrogen is mixed with boil-off gas or forced vaporization gas as fuel. In this way, by co-firing a mixed gas of natural gas and hydrogen as fuel, the amount of pollutants contained in the exhaust gas, especially carbon dioxide, can be reduced.

The fuel supply device 100 of this embodiment includes a storage tank (not shown) for storing LNG, and compresses the boil-off gas generated by natural vaporization of the LNG stored in the storage tank to the pressure required by the engine 200 to produce an engine ( A compressor (not shown) that supplies to the engine 200), a supply pump (not shown) that pressurizes the LNG stored in the storage tank to the pressure required by the engine 200, and the LNG pressurized by the supply pump is vaporized to produce the engine 200. ) Includes a vaporizer (not shown) that supplies.

In addition, the fuel supply device 100 is a reliquefaction device (not shown) that reliquefies the remaining boil-off gas in an amount that exceeds the amount of gas fuel required by the engine 200 among the boil-off gas compressed in the compressor and returns it to the storage tank. may further include.

The carbon dioxide reformer 300 according to this embodiment reforms carbon dioxide contained in the exhaust gas discharged from the engine 200 to generate carbon monoxide (CO) and hydrogen (H ₂ ).

The exhaust gas discharged from the engine 200 contains various combustion products such as carbon dioxide (CO ₂ ), nitrogen (N ₂ ), and water vapor (H ₂ O).

According to this embodiment, the exhaust gas discharged from the engine 200 can be sent to the carbon dioxide reformer 300 before being released into the atmosphere to decompose the carbon dioxide into carbon monoxide and hydrogen through a reforming reaction.

In addition, according to this embodiment, in order to reform carbon dioxide in the carbon dioxide reformer 300, a reformed gas supply line (CL) is provided to supply natural gas (CH ₄ ) from the fuel supply device 100 to the carbon dioxide reformer 300. More may be included.

Natural gas supplied to the carbon dioxide reformer 300 through the reformed gas supply line (CL) is liquid LNG stored in a storage tank, liquid LNG pressurized by a supply pump, boil-off gas generated in the storage tank, and compressor. It may be one or more of boil-off gas compressed in or forced vaporization gas vaporized in a vaporizer.

In the carbon dioxide reformer 300, the natural gas supplied from the fuel supply device 100, that is, methane, and the carbon dioxide in the exhaust gas transferred from the engine 200 undergo a reforming reaction to produce carbon monoxide (CO) and hydrogen (H ₂ ). is created.

Hydrogen generated in the carbon dioxide reformer 300 may join the gaseous fuel flow supplied from the fuel supply device 100 to the engine 200 through the hydrogen supply line HL. Hydrogen supplied to the engine 200 from the carbon dioxide reformer 300 through the hydrogen supply line (HL) may contain some carbon monoxide.

In addition, it may further include a mixer 110 that mixes the gaseous fuel supplied from the fuel supply device 100 to the engine 200 through the fuel supply line FL and the hydrogen generated in the carbon dioxide reformer 300. .

Alternatively, a hydrogen storage device (not shown) that temporarily stores hydrogen generated in the carbon dioxide reformer 300 and then supplies it to the mixer or engine 200 may be further included.

According to this embodiment, in order to supply hydrogen to the engine 200 capable of hydrogen co-combustion, hydrogen is generated from the exhaust gas of the engine 200, and carbon dioxide emissions generated by the engine 200 can be reduced.

In order to generate hydrogen, a carbon dioxide reformer 300 is provided to generate hydrogen by reforming carbon dioxide generated in the engine 200 and LNG, a fuel. The generated hydrogen and carbon monoxide are mixed with LNG as fuel and supplied as fuel to the engine 200. By mixing hydrogen with the LNG fuel supplied to the engine 200, the amount of carbon dioxide generated in the exhaust gas is reduced, and the generated carbon dioxide is converted into carbon monoxide and hydrogen in the carbon dioxide reformer 300, thereby eliminating or reducing carbon dioxide emissions from the ship.

In this way, without having a hydrogen storage tank and a hydrogen generation device on board, hydrogen is generated by reforming carbon dioxide from the exhaust gas of the engine 200 using the carbon dioxide reformer 300, and then mixed with natural gas to create engine ( By supplying the fuel as fuel in the engine 200, lean combustion can be achieved in the engine 200, thereby reducing the amount of carbon dioxide generated in the exhaust gas.

If the amount of carbon dioxide in the exhaust gas is reduced by co-firing hydrogen with natural gas, the amount of hydrogen produced in the carbon dioxide reformer 300 will also be reduced, and the hydrogen co-firing ratio of the fuel supplied to the engine 200 will be reduced, thereby reducing the amount of carbon dioxide generated in the exhaust gas. may increase again. Even so, since hydrogen can be generated again in the carbon dioxide reformer 300 and co-fired, as a result, the amount of carbon dioxide emitted into the atmosphere can be eliminated or reduced compared to the past.

It is obvious to those skilled in the art that the present invention is not limited to the above-mentioned embodiments, and that it can be implemented with various modifications or variations without departing from the technical gist of the present invention. It was done.

100: fuel supply device
110: mixer
200: engine
300: Carbon dioxide reformer
CL: Reformed gas supply line
FL: Fuel supply line
HL: Hydrogen supply line

Claims (6)

An engine that uses hydrocarbon-based liquefied gas or a mixed gas of hydrocarbon-based liquefied gas and hydrogen as fuel;
a carbon dioxide reformer that generates hydrogen by reforming carbon dioxide in the exhaust gas discharged from the engine;
A fuel supply device that supplies liquefied gas fuel to the engine; and
A carbon dioxide emission reduction system including; a hydrogen supply line that joins the hydrogen generated in the carbon dioxide reformer to the gaseous fuel flow supplied from the fuel supply device to the engine. In claim 1,
A reformed gas supply line that supplies liquefied gas from the fuel supply device to the carbon dioxide reformer. In claim 1,
A carbon dioxide emission reduction system in which hydrogen transferred from the carbon dioxide reformer through a hydrogen supply line is mixed with carbon monoxide. In claim 1,
A mixer that mixes the gaseous fuel supplied to the engine from the fuel supply device and the hydrogen transferred through the hydrogen supply line and supplies the mixture to the engine. In claim 1,
The fuel supply device,
A storage tank storing the liquefied gas;
A compressor that compresses the evaporative gas generated in the storage tank to the pressure required by the engine;
A supply pump that pressurizes the liquefied gas stored in the storage tank to the pressure required by the engine; and
A carbon dioxide emission reduction system comprising: a vaporizer that vaporizes the liquefied gas pressurized by the supply pump. A ship comprising a carbon dioxide emission reduction system according to any one of claims 1 to 5.

Images