KR102291923B1 - The Dual Fuel Engine fitted Breaking Resistor Operating Method and System on Gas Carrier Ship - Google Patents

Abstract

The present invention is a method and system for operating an engine of a ship using a braking resistor. According to the present invention, steam production in a waste heat recovery system is low due to a low load on the engine, such as when a ship enters a port or departs a port, during winter or low outdoor air conditions during operation. When this is insufficient, the fuel cost can be reduced by using only gas fuel as a heat source for steam production without consuming fuel oil through the auxiliary boiler by maintaining the load of the engine of the ship arbitrarily high. In addition, since only gas fuel is used, it is possible to reduce the emission of air pollutants without additionally installing a device for reducing nitrogen oxides (NOx) and sulfur oxides (SOx) in the engine of the ship, and it is possible to satisfy environmental regulations.
A method and system for operating an engine of a ship using a braking resistor according to the present invention is a method for operating an engine of a ship operating a liquefied gas, the steam produced in a waste heat recovery system that recovers waste heat of exhaust gas of a dual fuel engine to produce steam When the amount of steam is insufficient to measure the amount of steam required for the ship, a braking resistor connected to the dual fuel engine is operated to maintain the load of the dual fuel engine high, and the amount of exhaust gas supplied to the waste heat recovery system is fixed It is characterized in that the operation of the auxiliary boiler operated with fuel oil included in the waste heat recovery system is suppressed, and the steam required for the ship is produced using only gas fuel through the economizer.

Description

The Dual Fuel Engine fitted Breaking Resistor Operating Method and System on Gas Carrier Ship

The present invention relates to a method and system for operating an engine of a ship using a braking resistor, and more particularly, to produce steam even when a liquefied gas carrier is manufactured, without using fuel oil to produce steam. It relates to a method and system for operating an engine of a ship using a braking resistor that does not emit pollutants and enables operation at a low fuel cost.

Recently, as deep-sea oil field development and drilling are actively progressing due to the increase in energy demand, the offshore drilling, processing, and reforming process of hydrocarbon energy sources such as oil and natural gas, which was conducted on land, can be carried out while floating in the sea. The plant is in the spotlight. Accordingly, research on systems and methods for saving the overall energy and cost of a ship floating at sea is ongoing.

Recently, a dual fuel engine (DF Engine) that uses gas as the main fuel for ships handling natural gas but can be driven with either fuel oil, that is, liquid fuel or gas fuel, has been applied. The system has been developed and is being used. It is eco-friendly and can meet international emission control standards for ships because the content of sulfur oxides (SOx) and nitrogen oxides (NOx) in the exhaust gas is lower than when only liquid fuel, that is, fuel oil is used as fuel, This has the advantage of saving fuel costs.

In particular, the International Maritime Organization (IMO) recently adopted measures to reduce greenhouse gas emissions from ships (EEDI, SEEMP) as compulsory regulations, and the International Port Association introduced the Environmental Ship Index (ESI) to provide incentives to eco-friendly ships. Relevant measures such as providing Accordingly, efforts have been made to satisfy environmental regulations by installing an exhaust gas recirculation (EGR) or low-temperature denitration facility (SCR), which is a nitrogen oxide reduction device. However, in accordance with the announcement of the International Maritime Organization's more strengthened air pollution prevention third regulation (Tier Ⅲ) scheduled for 2016, the demand for nitrogen oxide and sulfur oxide reduction systems in ships' engines is increasing day by day.

In addition, in order to improve the energy efficiency of a ship, a waste heat recovery system that recycles waste heat of exhaust gas of a dual fuel engine to generate steam, which is a heat source required for an apparatus or process system installed on a ship, is also applied. The configuration of the system is shown in FIG. 1 .

As shown in Figure 1, the waste heat recovery system recovers the exhaust gas discharged from the dual fuel engine 10 and heats the waste heat with water in an economizer (Exhaust Gas Economizer, EGE, 20) to produce steam to produce steam in the engine room or steam. supply to consumables.

When such a waste heat recovery system is applied, in general, when the speed of the ship decreases, the steam consumption in the ship decreases accordingly. The consumption of steam does not decrease due to the operation of However, the amount of steam produced through the economizer 20 of the waste heat recovery system decreases as the load on the engine 10 decreases, and in order to cover the insufficient steam consumption, the auxiliary boiler 30 operated with fuel oil as fuel. must drive in parallel. Therefore, the use of liquid fuel, which is more expensive than gas fuel, not only increases the fuel cost, but also causes environmental problems as air pollutants such as nitrogen oxide (NOx) and sulfur oxide (SOx) are emitted when liquid fuel is used. There is a downside to

1. Korea Patent Publication No. 10-2014-0085003

Accordingly, the present invention is to solve the problems of the prior art as described above, and the load of the engine is arbitrarily maintained high even when the ship is manufactured, that is, when the ship enters or leaves the port, or when the ship is anchored, To provide a method and system for operating an engine of a ship using a braking resistor that reduces cost and environmental problems by using only gas fuel without operating an auxiliary boiler to produce steam with a waste heat recovery system there is a purpose to

According to one aspect of the present invention for achieving the above object, in the engine operating method of a liquefied gas operating vessel, the amount of steam produced in the waste heat recovery system for producing steam by recovering the waste heat of the exhaust gas of the dual fuel engine When the amount of steam required for the ship is insufficient by measuring By doing so, the operation of the auxiliary boiler operated with fuel oil included in the waste heat recovery system is suppressed, and the steam required for the ship is produced using only the gas fuel through the economizer. this is provided

Preferably, the braking resistor absorbs and stores excess energy for the increased load of the engine, or uses the excess energy as a heat source for the vessel and consumes it, and the braking resistor is overheated while absorbing excess energy. can be cooled by receiving the ship's cooling water.

Preferably, the excess energy absorbed by the braking resistor may be used as a heat source for generating steam for the vessel.

Preferably, when the amount of steam produced by the economizer (Exhaust Gas Economizer, EGE) included in the waste heat recovery system is measured by a flow measurement means and is insufficient than the required amount, the engine load regulator that controls the operation of the braking resistor is electrically It may further include sending a signal to activate the braking resistor.

In addition, according to another aspect of the present invention, in the engine operating method of a liquefied gas operating vessel, the gas fuel operation mode of the dual fuel engine by adjusting the load of the dual fuel engine of the vessel to be high when the vessel is managed. By maintaining, reducing greenhouse gas in the exhaust gas of the ship, the excess energy of the dual fuel engine is supplied to a braking resistor electrically connected to the dual fuel engine for absorption. A method of operation is provided.

In addition, according to another aspect of the present invention, in the engine operating system of a liquefied gas operating vessel, a dual fuel engine using gas fuel as a main fuel, but receiving both gas fuel and liquid fuel as fuel; and a braking resistor electrically connected to the engine propulsion device of the dual fuel engine, wherein the braking resistor is an excess energy of the engine so that the engine load can be maintained high when the engine load is reduced during the maintenance of the vessel. There is provided an engine operating system for a ship using a braking resistor, characterized in that it absorbs

Preferably, it includes a waste heat recovery system including an economizer that receives exhaust gas generated from the dual fuel engine and generates steam with the waste heat, and supplies the steam produced by the economizer to a steam consuming place of a ship. line; and flow rate measurement means for measuring the amount of steam produced by the economizer, wherein the flow measurement means sends an electrical signal to the braking resistor when the amount of steam supplied to the steam consuming place is less than the steam demand of the ship The braking resistor may be activated.

Preferably, it may further include an engine load regulator electrically connected to the braking resistor and the flow rate measuring means to receive a signal from the flow rate measuring means to control the operation of the braking resistor.

Preferably, the flow rate measuring means may be a pressure sensor installed in the steam supply line.

Preferably, the braking resistor absorbing the excess energy may use or store the absorbed excess energy as a heat source for generating steam.

Preferably, the liquefied gas is LNG (Liquefied Natural Gas), and the gas fuel of the dual fuel engine may be BOG (Boil Off Gas) of LNG or natural gas obtained by vaporizing LNG.

In addition, according to another aspect of the present invention, in the engine operating system of a liquefied gas operating vessel, a dual fuel engine using a gas fuel as a main fuel; a braking resistor electrically connected to the dual fuel engine to absorb excess energy of the dual fuel engine; and an economizer for producing steam by using waste heat of exhaust gas discharged from the dual fuel engine, wherein, when a ship in which the load of the dual fuel engine is reduced, operates the braking resistor to reduce the load of the dual fuel engine By maintaining high, there is provided an engine operating system for a ship using a braking resistor, characterized in that it receives only gas fuel and maintains a constant amount of steam produced by the economizer.

According to the present invention, when the steam production in the waste heat recovery system is insufficient due to the low engine load such as winter or low outdoor air conditions during operation, when the ship enters or departs from the port, the load of the engine of the ship is arbitrarily maintained high to operate the auxiliary boiler. Fuel cost can be reduced by using only gas fuel as a heat source for steam production without consuming fuel oil.

In addition, since only gas fuel is used, it is possible to reduce the emission of air pollutants without additionally installing a device for reducing nitrogen oxides (NOx) and sulfur oxides (SOx) in the engine of the ship, and it is possible to satisfy environmental regulations.

1 is a configuration diagram schematically showing an engine operating system of a ship according to the prior art.
2 is a configuration diagram schematically illustrating an engine operating system of a ship using a braking resistor according to an embodiment of the present invention.

In order to fully understand the operational advantages of the present invention and the objects achieved by the practice of 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 configuration and operation of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, in adding reference numerals to the components of each drawing, it should be noted that only the same components are marked with the same reference numerals as much as possible even though they are displayed on different drawings.

The present invention operates at sea such as ships operating liquefied gas, that is, LNG Carrier (LNGC), Liquefied Ethane Gas Carrier (LEGC), and LNG Fueled Ship (LFS). It can be applied to all ships and floating structures on the sea that have a device capable of storing liquefied gas. However, it is not limited thereto, and gas is the main fuel in engine operation, and in particular, BOG (Boil Off Gas) of liquefied gas stored in the storage tank of the ship or gas obtained by vaporizing liquefied gas can be supplied as fuel for the engine. It can be applied to existing engines and their systems.

2 is a view for explaining an engine operating system of a ship using a braking resistor according to an embodiment of the present invention. As shown in FIG. 2, the engine operating system of a ship using a braking resistor according to an embodiment of the present invention includes a dual fuel engine 10, an engine propulsion device 40, and a braking resistor (BR). include

The dual fuel engine 10 is a vaporized gas naturally vaporized or forced vaporized from liquid fuel such as HFO (Heavy Fuel Oil), MDO (Marine Diesel Oil) and MGO (Marine Gas Oil) and natural gas and liquefied gas, for example. For power generation, all gas fuels such as BOG (Boil-Off Gas) can be used as fuel, and gas fuel is the main fuel, but the listed fuels are set to each mode and selectively supplied and operated Or it may be an engine for propulsion. In this embodiment, as an example, it is applied to a dual fuel diesel electric propulsion method, that is, DFDE (Dual Fuel Diesel Electric), in which power is generated by receiving dual fuel and using the electric energy to turn a motor or a propeller to obtain propulsion. do.

The engine propulsion device 40 may receive electric energy from the dual fuel engine 10 and convert it into kinetic energy of a motor and a propeller to control the speed of the vessel.

The braking resistor BR may be installed in the engine propulsion device 40 and may be electrically connected to the engine propulsion device 40 . Accordingly, the braking resistor BR is a kind of current consuming place, that is, a load device, and can be used as a heat source for storing excess energy or converting excess energy into thermal energy to produce steam.

The engine operating system of a ship using a braking resistor according to an embodiment of the present invention may further include a waste heat recovery system. The waste heat recovery system recovers the exhaust gas discharged from the dual fuel engine 10 and reuses the waste heat of the dual fuel engine 10 by using the waste heat as a heat source to produce steam. The waste heat recovery system is an economizer 20 that heat exchanges between the exhaust gas supplied from the dual fuel engine 10 and water and produces steam, and the amount of the exhaust gas is insufficient to produce steam. , a steam supply line for supplying the steam produced from the economizer 20 and the auxiliary boiler 30 to the steam consuming place in the ship and the auxiliary boiler 30 that receives liquid fuel and produces steam instead of the insufficient heat source with the combustion heat (SL) may be included.

The economizer 20 may be connected and installed one for each dual fuel engine 10 or one for each dual fuel engine 10 to receive exhaust gas from the dual fuel engine 10 . Water supplied to the economizer 20 by obtaining heat from the waste heat of the exhaust gas becomes steam. Water supplied to the economizer 20 may be stored in a cascade tank and may be supplied to the economizer 20 through a water pump.

When the amount of exhaust gas supplied to the economizer 20 is insufficient, some of the supplied water does not become steam and a mixture of water and steam may be discharged from the economizer 20, which is the auxiliary boiler ( 30), that is, the gas-liquid separation is performed so that water is re-supplied to the economizer 20 and steam may be supplied to the steam supply line SL.

The steam supply line SL may be provided with a flow rate measuring means PT for measuring the amount of steam supplied to the steam sink. The flow rate measuring means PT may be a pressure sensor PT that measures the amount of steam by the pressure of a pipe of the steam supply line SL.

For example, when a ship to which the dual fuel engine 10 and the waste heat recovery system is applied is anchored in a port and a manoeuvring operation is required, the speed of the ship is reduced, so that the load of the engine 10 is increased. As the amount of exhaust gas decreases, the amount of steam produced through the economizer 20 decreases. However, the steam consumption in the ship does not decrease due to the operation of cargo equipment for loading and unloading LNG. At this time, instead of supplying the insufficient amount of steam through the auxiliary boiler 30 operated with liquid fuel, the braking resistor BR is operated to maintain the load of the dual fuel engine 10 higher than a specific value. The amount of exhaust gas supplied from the dual fuel engine 10 to the economizer 20 may be constantly maintained.

Here, the specific value may be a load value of the dual fuel engine 10 required to discharge the amount of exhaust gas required to produce the economizer 20 by the amount of steam required by the ship.

At this time, when an amount less than the amount of steam required by the ship is supplied to the steam supply line SL, the flow measurement means PT transmits an electrical signal to the control means ELC, and the control means ELC ) may receive a measurement value from the flow measurement means PT and control the operation of the braking resistor BR.

In other words, when the load of the dual fuel engine 10 is operated below a specific value and the amount of steam produced by the economizer 20 is less than the required amount, the braking resistor BR is operated to arbitrarily the dual fuel engine. The amount of exhaust gas supplied to the economizer 20 can be constantly maintained by driving the load at (10) high and allowing an excess current generated accordingly to flow to the braking resistor (BR). That is, the amount of steam discharged from the economizer 20 may be maintained at 7 to 9 barg.

As described above, in the present invention, when the amount of exhaust gas is reduced as the load of the dual fuel engine 10 of the ship is reduced and the amount of steam produced by the economizer 20 is insufficient, the fuel oil channel assists as in the conventional method. In the dual fuel engine 10, by maintaining the load of the dual fuel engine 10 operable with gas fuel arbitrarily high by installing a braking resistor (BR) without operating the boiler 30 to cover the lack of steam. It is to ensure that the amount of generated exhaust gas is sufficient so that the required amount of steam can be constantly generated in the ship only with gas fuel.

In general, the amount of steam produced when the auxiliary boiler 30 is operated at 100% load is 6500 kg/h, and the minimum load of the auxiliary boiler 30 is about 33%, The shortfall is about 400-800 kg/h. That is, when the auxiliary boiler 30 is operated to cover the insufficient amount of steam, 6500 * 0.33 = 2145 kg/h of steam must be produced inevitably, and the remaining steam is discarded.

On the other hand, when the dual fuel engine 10 requires additional steam of 1000 kg/h, it needs to be operated at a load of about 75%, and the load of the dual fuel engine 10 used as a basis is about 50%, which is about 25%. additional load is required. Therefore, the dual fuel engine 10 is operated by arbitrarily increasing the load of about 25%, and the generated excess current flows to the braking resistor BR.

In addition, in general, the thermal efficiency of the auxiliary boiler 30 is about 85%, the calorific value per 1 kW of power is about 860 kcal/hr, and the calorific value of fuel oil is about 561 kcal/kg, so To produce steam, 800*561/(0.85*860) = 613kW of fuel oil is required.

On the other hand, the efficiency of the dual fuel engine 10 is about 45%, and the gas fuel required when operating the dual fuel engine 10 at 100% load is about 8775 kW, so that about 75% of the load, that is, the dual fuel engine 10 . In order to operate an additional load of about 25% rather than the minimum load of 50%, 0.45*8775*0.25=987kW of gas fuel is required.

The auxiliary boiler 30 uses fuel oil as a fuel, and the dual fuel engine 10 uses gas as a main fuel, and the cost of gas is 1/3 to 1/4 compared to fuel oil. Assuming that the fuel cost of the auxiliary boiler 30 is 1 per kW, the fuel cost required to operate the auxiliary boiler 30 to generate the steam shortage is 613, while the dual fuel engine 10 is operated to reduce the steam shortage. To generate it, only the fuel cost of 987kw*0.3=329 is required.

Therefore, when the embodiment of the present invention is applied to a ship, it is possible to save energy costs for steam, which had to be produced and discarded due to the minimum load in the auxiliary boiler 30, as well as the compared fuel oil and gas It is also possible to save in terms of fuel cost. In addition, it can be advantageously applied from an environmental point of view by producing steam using a gas that emits less air pollutants as a fuel instead of using fuel oil as a fuel.

It is obvious to those of ordinary skill in the art that the present invention is not limited to the above embodiments and can be implemented with various modifications or variations without departing from the technical gist of the present invention. will be.

1: Waste heat recovery system ELC: Engine load regulator
10: dual fuel engine BR: braking resistor
20: economizer PT: pressure sensor
30: auxiliary boiler SL: steam supply line
40: engine propulsion device

Claims (12)

In the engine operating method of a liquefied gas operating vessel,
The waste heat recovery system is used to recover the waste heat from the exhaust gas of the dual fuel engine to produce steam.
Supplying the produced steam to a steam consumer on board,
When the amount of steam produced by the waste heat recovery system is insufficient than the amount required by the steam consuming place on board, the dual fuel engine is operated higher than the actual required load, and a braking resistor connected to the dual fuel engine is operated. to consume the excess energy produced by the dual fuel engine in the braking resistor,
By operating a high load of the dual fuel engine, the exhaust gas of the dual fuel engine maintains an amount of heat required to produce steam in an amount that satisfies the requirements of in-board steam consumers in the waste heat recovery system. A method of operating a ship's engine using a register. The method according to claim 1,
The braking resistor absorbs and stores excess energy for the increased load of the engine, or consumes the excess energy by using the excess energy as a heat source required for the vessel,
The braking resistor, which is overheated while absorbing excess energy, is supplied with the ship's coolant and cooled. 3. The method according to claim 2,
Excess energy absorbed by the braking resistor is used as a heat source for producing steam of the ship. The method according to claim 1,
When the amount of steam produced by the economizer (Exhaust Gas Economizer, EGE) included in the waste heat recovery system is measured with a flow rate measuring means and is less than the required amount, an electrical signal is sent to the engine load regulator that controls the operation of the braking resistor. A method of operating an engine of a ship using a braking resistor, further comprising actuating the braking resistor. delete In the engine operating system of a liquefied gas operating vessel,
a dual fuel engine using gas fuel as the main fuel, but receiving both gas fuel and liquid fuel as fuel;
a waste heat recovery system including an economizer that recovers waste heat of the exhaust gas of the dual fuel engine and produces steam;
a steam consumer that receives and uses the steam produced by the waste heat recovery system;
a braking resistor electrically connected to the engine propulsion device of the dual fuel engine; and
When the amount of steam produced by the waste heat recovery system is insufficient than the amount required by the steam consuming place, the load of the dual fuel engine is driven higher than the actual required load, and a braking resistor connected to the dual fuel engine is operated , control means for allowing the excess energy produced by the dual fuel engine to be consumed in the braking resistor;
The control means, in the operation mode of the ship in which the load of the dual fuel engine is reduced, by operating the load of the dual fuel engine higher than the actual required load, the exhaust gas of the dual fuel engine is in the ship in the waste heat recovery system A marine engine operating system that uses a braking resistor to maintain the amount of heat needed to produce an amount of steam that meets the requirements of a steam consumer. 7. The method of claim 6,
Further comprising a flow rate measuring means for measuring the amount of steam produced by the economizer,
When it is determined that the amount of steam supplied to the steam consuming place is less than the steam demand of the ship according to the measured value of the flow measurement means, the control means sends an electrical signal to the braking resistor to operate the braking resistor A ship's engine operating system using a braking resistor characterized in delete 8. The method of claim 7,
The engine operating system of a vessel using a braking resistor, characterized in that the flow measurement means is a pressure sensor installed in the steam supply line. 7. The method of claim 6,
The braking resistor absorbing the excess energy uses or stores the absorbed excess energy as a heat source to produce steam. 7. The method of claim 6,
The liquefied gas is LNG (Liquefied Natural Gas), and the gas fuel of the dual fuel engine is BOG (Boil Off Gas) of LNG or Natural Gas obtained by vaporizing LNG. of the engine operating system. delete

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