KR102626178B1 - Fuel Supply System For Ship - Google Patents

Abstract

A fuel supply system for the ship is provided. The fuel supply system for a ship of the present invention includes a fuel supply line provided on a ship and connected from an ammonia storage tank storing ammonia to an engine on board the ship; A compression unit provided in the fuel supply line and compressing ammonia to the pressure required for the engine; A fuel recovery line that recovers ammonia discharged from the engine; An exhaust discharge line that discharges exhaust gases generated from the engine outboard; and a selective catalytic reduction unit provided in the exhaust discharge line to denitrify the exhaust gas, wherein ammonia is supplied from the ammonia storage tank or the fuel supply line as a reducing agent to the selective catalytic reduction unit.

Description

Fuel supply system for ships {Fuel Supply System For Ship}

The present invention relates to a fuel supply system for ships, and more specifically, to supply ammonia as fuel for engines onboard ships to meet regulatory standards set by international conventions and reduce nitrogen oxides in exhaust gases emitted from engines when supplying ammonia fuel. It is about a fuel supply system for ships that can

As the global warming phenomenon intensifies, efforts are being made to reduce greenhouse gas emissions around the world, and as the 1997 Kyoto Protocol, which included obligations for developed countries to reduce greenhouse gases, expires in 2020, the event held in Paris, France in December 2015 The 195 parties participating in the Paris Climate Change Accord, which was adopted at the 21st United Nations Framework Convention on Climate Change and came into effect in November 2016, are making various efforts with the goal of reducing greenhouse gases.

Along with this global trend, interest in renewable energy (or renewable energy) such as wind power, solar power, solar heat, bioenergy, tidal power, and geothermal heat as a pollution-free energy that can replace fossil fuels and nuclear power is increasing, and various technologies are being developed. I'm losing.

Although LNG is considered an eco-friendly fuel compared to other fossil fuels, it still produces carbon dioxide when burned, and ships that use it as fuel emit carbon dioxide during operation.

Several studies are being conducted on eco-friendly fuels that can reduce carbon dioxide emissions during ship operations, and recently, technologies for ship engines that can use hydrogen, ammonia, etc. as fuel are being developed.

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 and applying one step every five years. However, for LPG carriers, EEDI Phase 3 will be applied early from 2022, two years after applying EEDI Phase 2. As international interest in climate change and greenhouse gas emissions grows, it has been decided that ships ordered after 2030 will reduce carbon emissions by 40% compared to ships ordered in 2008, and by 50% by 2050. As regulations are rapidly being strengthened, the need for alternative fuels is increasing.

In particular, if the standards of Phase 4 (40% reduction in carbon dioxide emissions) or higher are applied in the future, it may be difficult to achieve carbon dioxide emission regulations for ships using current LNG or LPG as fuel. In order to completely decarbonize shipping from a long-term perspective, ships Since it is inevitable to replace fuel with carbon-neutral fuel, there is a need to further expedite the development of technology for eco-friendly ship fuel and its application to ships.

Among carbon-neutral fuels, ammonia (NH ₃ ) is a substance in which 3 hydrogens are bonded to 1 nitrogen. It can form strong hydrogen bonds between molecules, making it easy to liquefy. It has a boiling point of -33.34°C and a melting point of -77.73 at normal pressure. It is ℃. Ammonia is particularly easy to store and transport, is easy to mass produce through the Haber-Bosch method, and has excellent economic efficiency compared to other carbon-neutral fuels, so research and development to use ammonia as a ship fuel is being actively conducted.

The present invention seeks to propose a method for supplying environmentally friendly fuel such as ammonia as engine fuel to a ship engine, thereby reducing nitrogen oxides in exhaust gas emitted from the engine when ammonia fuel is supplied.

According to one aspect of the present invention for solving the above-described problem, a fuel supply line provided on a ship and connected from an ammonia storage tank storing ammonia to an engine on board the ship;

A compression unit provided in the fuel supply line and compressing ammonia to the pressure required for the engine;

A fuel recovery line that recovers ammonia discharged from the engine;

An exhaust discharge line that discharges exhaust gases generated from the engine outboard; and

A selective catalytic reduction unit provided in the exhaust discharge line to denitrify the exhaust gas,

A fuel supply system for a ship is provided, wherein ammonia is supplied as a reducing agent to the selective catalytic reduction unit from the ammonia storage tank or the fuel supply line.

Preferably, a reducing agent supply line connected from the ammonia storage tank to the selective catalytic reduction unit; A reducing agent supply pump provided in the reducing agent supply line to transport ammonia from the ammonia storage tank; and a reducing agent supply unit that supplies ammonia transferred from the reducing agent supply pump to the selective catalytic reduction unit.

Preferably, the compression unit includes a fuel supply pump that transfers ammonia from the ammonia storage tank; and a pressurizing pump that pressurizes the ammonia transferred from the fuel supply pump to the pressure required by the engine.

Preferably, a reducing agent supply line connected to the selective catalytic reduction unit at a rear end of the fuel supply pump of the fuel supply line; and a reducing agent supply unit provided in the reducing agent supply line and supplying ammonia to the selective catalytic reduction unit.

Preferably, an exhaust gas analyzer provided in the exhaust discharge line to analyze the concentration of nitrogen oxides and unreacted ammonia in the exhaust gas discharged from the engine; and a reducing agent supply pump provided upstream of the reducing agent supply unit in the reducing agent supply line and driven by a variable frequency drive (VFD).

Preferably, when ammonia slip is detected according to the analysis result in the exhaust gas analyzer, the flow rate of ammonia supplied to the selective catalytic reduction unit through the reducing agent supply pump and the reducing agent supply unit can be adjusted.

Preferably, a reducing agent filter is provided upstream of the reducing agent supply part in the reducing agent supply line and removes lubricating oil from ammonia; And it may further include a differential pressure sensor that detects the differential pressure between the front and rear ends of the reducing agent filter in the reducing agent supply line.

In the present invention, ammonia, an eco-friendly fuel, is supplied as fuel for marine engines to reduce greenhouse gas emissions during ship operation and meet regulatory standards set by international conventions.

In particular, when ammonia is supplied as engine fuel, nitrogen oxides in the exhaust gas may be contained in greater quantities than when using LPG or oil as fuel. By providing a selective catalytic reduction unit, nitrogen oxides in the exhaust are reduced and ammonia is supplied as a reducing agent. It helps reduce installation costs and installation space, such as a storage tank for supplying a separate reducing agent.

1 to 3 schematically show a fuel supply system for a ship according to first to third embodiments 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.

Hereinafter, the ship in the present invention refers to all types of ships equipped with an engine that can use ammonia as fuel for the ship's engine, and representative examples include LPG carrier (LNG Carrier), LNG carrier (LNG Carrier), liquid hydrogen carrier, and ammonia carrier. , vessels with self-propulsion capabilities such as container carriers, crude oil carriers, bulk carriers of minerals or grains, and Ro-Ro (Roll on/roll off) ships, as well as offshore structures that do not have propulsion capabilities but are floating at sea. may also be included.

Engines supplied with ammonia as fuel include those supplied with ammonia as fuel together with other marine fuels such as LNG, LPG, HFO, MGO, and Diesel Oil, and those supplied with ammonia alone as fuel. Includes both propulsion engines and power generation engines.

1 to 3 schematically show a fuel supply system for a ship according to the first to third embodiments of the present invention.

As shown in Figures 1 to 3, the fuel supply system of the present embodiments includes a fuel supply line (SL) provided on the ship and connected from the ammonia storage tank (T) that stores ammonia to the engine (E) on board the ship, and a fuel supply line (SL) It is provided in the supply line and includes a compression unit 100 that compresses ammonia to the pressure required for the engine, and a fuel recovery line (RL) that recovers ammonia discharged from the engine.

Ammonia is supplied from the ammonia storage tank (T) to the engine (E) along the fuel supply line (SL), and fuel not consumed by the engine can be discharged from the engine along the fuel recovery line and then recirculated.

The compression unit 100 includes a fuel supply pump 110 that transfers ammonia from the ammonia storage tank, and a pressurization pump 120 that pressurizes the ammonia transferred from the fuel supply pump to the pressure required by the engine, and includes a fuel supply pump and Through a pressurized pump, ammonia is supplied as fuel to the engine (E) in a high-pressure liquid state.

At the rear of the compression unit 100 along the fuel supply line (SL), there is a temperature control unit 200 that adjusts the ammonia compressed by the pressurization pump to the temperature required by the engine, and a temperature control unit 200 that receives ammonia that has passed through the temperature control unit and filters out foreign substances. A filter 250 for output and transfer may be provided.

Downstream of the compression section of the fuel supply line, a supply valve train (SVT) is installed with valves that control the supply of ammonia to the engine, and supplies ammonia transferred through the compression section, temperature control section, and filter to the engine.

On the other hand, when liquid ammonia, an incompressible fluid whose volume changes little or no change even when pressure is applied, is supplied as engine fuel, excess liquid fuel is supplied to the engine to respond to changes in engine load and prevent cavitation. Among the liquid fuel supplied to the engine, the remaining fuel consumed as fuel and the liquid fuel remaining in the engine when the engine is stopped are discharged from the engine. To this end, a fuel recovery line (RL) is installed to recover and recirculate unconsumed ammonia from the engine. It is prepared. The fuel recovery line is equipped with a return valve train (RVT) in which valves are installed to control ammonia recovery from the engine.

Ammonia discharged from the engine (E) is recovered along the fuel recovery line (RL) through the return valve train (RVT), and the liquid ammonia among the recovered fuel can be transferred back to the fuel supply line and recirculated into the engine. .

Exhaust gas generated from the engine is discharged overboard through an exhaust discharge line (EL), and a selective catalytic reduction unit 300 is provided in the exhaust discharge line to denitrify the exhaust gas. When ammonia is supplied as engine fuel, the exhaust gas may contain more nitrogen oxides than when using LPG or oil as fuel, and nitrogen oxides are also substances whose emissions are regulated by the IMO.

In this embodiment, in order to remove this, a selective catalytic reduction unit 300 is provided in the exhaust discharge line EL, and nitrogen oxides are reduced through a reduction reaction. Urea aqueous solution ((NH ₂ ) ₂ CO) is often used as a reducing agent in the selective catalytic reduction unit. When urea is stored in an aqueous solution, its useful life decreases over time and a constant temperature must be maintained for this purpose. There is a problem of installation space and installation cost.

In the present embodiments, ammonia supplied as engine fuel instead of urea is directly used as a reducing agent in the selective catalytic reduction unit, and liquid ammonia is supplied from the ammonia storage tank (T) or the fuel supply line (SL) to the selective catalytic reduction unit (300). A reducing agent supply line (AL, ALa, ALb) is provided to supply ammonia as a reducing agent for denitrification of exhaust gas to the selective catalytic reduction unit. This can solve the problem of separate installation space and installation costs for supplying reducing agents such as urea tanks.

The reducing agent supply line is provided with a reducing agent supply unit 310 that includes a reducing agent heater that heats ammonia to be supplied to the selective catalytic reduction unit and a reducing agent valve that opens and closes the reducing agent supply line. Ammonia injected into the SCR Reactor of the selective catalytic reduction unit 300 through the reducing agent supply unit 310 reacts with NOx in the presence of a catalyst and changes into N ₂ and H ₂ O, reducing the NOx content in the exhaust. The reaction formula is as follows.

Let's look at the differences between each embodiment.

First, in the first embodiment system shown in FIG. 1, the reducing agent supply line (AL) is connected from the ammonia storage tank (T) to the selective catalytic reduction unit 300, so that ammonia from the ammonia storage tank can be supplied as a reducing agent. . The reducing agent supply line is provided with a reducing agent supply pump 320 to transfer ammonia to the reducing agent supply unit 310 and supply it to the selective catalytic reduction unit.

Next, in the second and third embodiment systems shown in FIGS. 2 and 3, the reducing agent supply line (ALa) is connected to the selective catalytic reduction unit 300 at the rear end of the fuel supply pump 110 of the fuel supply line, that is, the low pressure pump. Therefore, the fuel supply pump 110 is configured so that it can be used to supply a reducing agent to the selective catalytic reduction unit.

First, in the second embodiment shown in FIG. 2, an exhaust gas analyzer 330 is provided in the exhaust discharge line EL to analyze the concentration of nitrogen oxides and unreacted ammonia in the exhaust gas discharged from the engine, and a reducing agent is supplied. Upstream of the reducing agent supply unit in the line, a reducing agent supply pump (320a) driven by a variable frequency drive (VFD) is provided.

If ammonia slip is detected during exhaust according to the results of the nitrogen oxide concentration and unreacted ammonia concentration analysis results of the exhaust gas analyzed by the exhaust gas analyzer 330, the reducing agent supply pump 320a and the reducing agent supply unit 310 are connected to the exhaust gas analyzer 330. By controlling, the ammonia flow rate supplied to the selective catalytic reduction unit 300 can be adjusted. This can prevent ammonia slip.

Meanwhile, in the third embodiment shown in FIG. 3, a reducing agent filter 340 for removing lubricating oil from ammonia is provided upstream of the reducing agent supply part in the reducing agent supply line (ALb), and the differential pressure before and after the reducing agent filter in the reducing agent supply line is adjusted. A differential pressure sensor 350 that detects is additionally provided.

As described above, when liquid ammonia is supplied as engine fuel, ammonia not consumed in the engine (E) may be discharged along the fuel recovery line (RL) and recirculated through the fuel supply line, as in the present embodiment. If ammonia is branched downstream of the fuel supply pump of the fuel supply line and supplied as a reducing agent, mixed lubricating oil may be mixed with ammonia recovered from the engine, and if supplied to the selective catalytic reduction unit, it may reduce the denitrification effect and cause equipment malfunction. In order to solve this problem, this embodiment additionally provides a reducing agent filter 340 to remove lubricating oil in the reducing agent supply line, and the differential pressure sensor 350 detects the differential pressure before and after the reducing agent filter to monitor the presence or absence of lubricating oil in ammonia. It was structured so that

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

E: engine
T: Ammonia storage tank
SL: Fuel supply line
RL: Fuel recovery line
EL: Exhaust discharge line
AL, ALa, ALb: reducing agent supply line
SVT: Supply valve train
RVT: Return valve train
100: Compression part
200: Temperature control unit
250: filter
300: Selective catalytic reduction unit
310: Reduction agent supply department

Claims (7)

A fuel supply line provided on the ship and connected from the ammonia storage tank that stores ammonia to the engine on board the ship;
A compression unit provided in the fuel supply line including a fuel supply pump for transferring ammonia from the ammonia storage tank and compressing ammonia to the pressure required for the engine;
A fuel recovery line that recovers ammonia discharged from the engine;
An exhaust discharge line that discharges exhaust gases generated from the engine outboard;
A selective catalytic reduction unit provided in the exhaust discharge line to denitrify exhaust gas;
A reducing agent supply line connected to the selective catalytic reduction unit at a rear end of the fuel supply pump of the fuel supply line;
a reducing agent supply unit provided in the reducing agent supply line and supplying ammonia to the selective catalytic reduction unit;
a reducing agent filter provided upstream of the reducing agent supply unit in the reducing agent supply line and removing lubricating oil from ammonia; and
It includes a differential pressure sensor that detects the differential pressure before and after the reducing agent filter in the reducing agent supply line,
Ammonia is supplied from the ammonia storage tank or fuel supply line as a reducing agent to the selective catalytic reduction unit,
A ship's fuel supply system characterized by monitoring the presence or absence of lubricant in ammonia by detecting the differential pressure at the differential pressure sensor. According to clause 1,
a second reducing agent supply line connected from the ammonia storage tank to the selective catalytic reduction unit;
a reducing agent supply pump provided in the second reducing agent supply line to transport ammonia from the ammonia storage tank; and
A ship's fuel supply system further comprising a second reducing agent supply unit that supplies ammonia transferred from the reducing agent supply pump to the selective catalytic reduction unit. The method of claim 1, wherein the compression unit
A fuel supply system for a ship further comprising a pressurization pump that pressurizes ammonia transferred from the fuel supply pump to the required pressure in the engine. delete According to clause 3,
An exhaust gas analyzer provided in the exhaust discharge line to analyze the concentration of nitrogen oxides and unreacted ammonia in the exhaust gas discharged from the engine; and
A fuel supply system for a ship further comprising: a reducing agent supply pump provided upstream of the reducing agent supply unit in the reducing agent supply line and driven by a variable frequency drive (VFD). According to clause 5,
A ship's fuel supply system, characterized in that when ammonia slip is detected according to the analysis results in the exhaust gas analyzer, the ammonia flow rate supplied to the selective catalytic reduction unit through the reducing agent supply pump and the reducing agent supply unit is adjusted. delete

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