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KR-102961174-B1 - LPG Recovery System For Ship

KR102961174B1KR 102961174 B1KR102961174 B1KR 102961174B1KR-102961174-B1

Abstract

An LPG recovery system for a ship is disclosed. The LPG recovery system for a ship according to the present invention comprises: a service tank provided on the ship and storing LPG to be supplied to an onboard engine; a fuel supply line supplying LPG from the service tank to the engine; a return line connecting the engine to the service tank; and a reliquefaction unit provided in the return line. When the LPG mode of the engine is stopped or a trip occurs, the LPG remaining in the fuel supply line is reliquefied in the reliquefaction unit and returned to the service tank.

Inventors

  • 김종현

Assignees

  • 한화오션 주식회사

Dates

Publication Date
20260507
Application Date
20200410

Claims (13)

  1. A service tank provided on the vessel to store LPG to be supplied to the onboard engines; A fuel supply line that supplies LPG from the service tank to the engine; A return line connecting the above engine to the above service tank; A re-liquefaction unit provided in the above return line; A urea tank provided on the above-mentioned vessel for storing urea to be supplied to an onboard selective catalytic reduction (SCR) unit; A chiller for supplying cooling water for cooling the urea solution stored in the above-mentioned urea solution tank; and A cooling line that circulates a portion of the cooling water from the above chiller to the above re-liquefaction unit: When the LPG mode of the engine stops, trips, or isolates, the LPG remaining in the fuel supply line is reliquefied in the reliquefaction unit and returned to the service tank, thereby preventing energy waste caused by releasing LPG into the atmosphere and preventing air pollution. The LPG returning to the service tank is cooled by heat exchange with the cooling water supplied from the chiller, and The above re-liquefaction unit includes a drum in which LPG returning to the service tank is recovered; and An LPG recovery system for a ship, characterized in that the cooling water supplied from the chiller through the cooling line exchanges heat with LPG in the drum.
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  4. In Article 1, The drum comprises: an LPG receiving portion for receiving LPG to be returned to the service tank; and a compression portion for applying compressive force to the LPG receiving portion. An LPG recovery system for a ship characterized by the cooling water supplied from the chiller cooling the LPG compressed in the LPG receiving section through heat exchange to liquefy it.
  5. In claim 4, the above re-liquefaction part A pressure selection valve provided in a pipe that supplies a working fluid for compressive force to the above-mentioned compression section; and A temperature sensor for detecting the temperature of the above LPG receiving portion is further included, An LPG recovery system for a ship characterized by supplying a working fluid of a different pressure to the compression unit through the pressure selection valve according to the temperature detected by the temperature sensor.
  6. In Paragraph 5, If the temperature detected by the temperature sensor is less than 20℃, 8 bar of nitrogen gas or compressed air is supplied to the compression unit by the pressure selection valve, and An LPG recovery system for a ship characterized in that if the temperature detected by the temperature sensor is 20℃ or higher, compressed air of 30 bar is supplied to the compression unit by the pressure selection valve.
  7. In claim 5, the above re-liquefaction part A gas-liquid separator for separating the gas supplied for purging the fuel supply line from the liquefied LPG in the above LPG receiving section; A discharge valve for discharging the gas separated in the above-mentioned gas-liquid separator; and An LPG recovery system for a ship further comprising a first recovery control valve for returning liquefied LPG from the above LPG receiving section to the above return line.
  8. In Article 7, A recovery storage tank provided downstream of the re-liquefaction unit in the above return line; and An LPG recovery system for a ship further comprising a second recovery control valve provided between the recovery storage tank and the service tank.
  9. In Clause 4, the above fuel supply line A transfer pump for transferring LPG from the above service tank; A compression pump that compresses the LPG transferred from the above transfer pump to the required pressure of the above engine; A temperature control unit that heats or cools the LPG compressed in the above compression pump to adjust it to the required temperature of the engine; and An LPG recovery system for a ship equipped with a filter that filters out foreign substances contained in LPG downstream of the temperature control unit.
  10. In Article 9, A service valve section provided between the filter of the fuel supply line and the engine, and upstream of the re-liquefaction section of the return line; First and second pressure relief lines respectively connected from the service valve portion of the fuel supply line and return line to the LPG receiving portion of the drum; and An LPG recovery system for a vessel further comprising a venting line connected from the return line to the LPG receiving section upstream of the second pressure relief line.
  11. In Clause 10, the above service valve part First and second valves provided at the upstream and downstream ends of the branch point of the first pressure relief line of the fuel supply line; A third valve provided in the first pressure relief line above; Fourth and fifth valves provided at the upstream and downstream ends of the branch point of the second pressure relief line of the above return line; An LPG recovery system for a vessel comprising a sixth valve provided in the second pressure relief line.
  12. In any one of paragraphs 9 through 11, When the LPG mode of the above engine stops or trips, the LPG from the transfer pump is transferred to the service tank, and An LPG recovery system for a ship, characterized in that LPG from a fuel supply unit including the above-mentioned compression pump, temperature control unit, and filter is cooled by heat exchange with cooling water supplied from the above-mentioned chiller, re-liquefied, and returned to the above-mentioned service tank.
  13. In Article 1, A service tank cooling line that circulates the cooling water from the above cooling line to the service tank; and An LPG recovery system for a ship further comprising a cooling jacket provided inside the service tank in the service tank cooling line to cool the service tank with the cooling water.

Description

LPG Recovery System for Ships The present invention relates to an LPG recovery system for a ship, and more specifically, to an LPG recovery system for a ship that re-liquefies LPG remaining in the fuel supply line and returns it to the service tank when the engine's LPG mode is stopped or trips occur in a ship using LPG as fuel. Conventional LPG carriers and the like employ a fuel supply system that uses heavy fuel oil, such as Bunker C oil, which is relatively inexpensive, as propulsion fuel for ships. However, due to stricter international exhaust emission regulations regarding the use of heavy fuel oil, these systems have had to install separate heavy fuel oil tanks (LSHFO tanks) with low sulfur content, and there has been a growing demand for an eco-friendly fuel supply system that meets international environmental standards. Recently, the application of fuel supply systems that use LPG or LNG and the boil-off gas generated therefrom as propulsion fuel is increasing in LPG or LNG carriers. Furthermore, due to the strengthening of international exhaust emission regulations, the number of general vessels using LNG or LPG as propulsion fuel is also increasing, in addition to LPG or LNG carriers. In particular, LPG is easier to store than LNG, which is liquefied at cryogenic temperatures, and it does not fall significantly short in specific energy and energy density compared to conventional HFO, while offering the advantage of excellent reduction effects in SOX, NOX, CO2, and PM compared to conventional HFO. FIG. 1 schematically illustrates an LPG recovery system of a ship according to a first embodiment of the present invention. FIG. 2 schematically illustrates an LPG recovery system of a ship according to a second embodiment of the present invention. In order to fully understand the operational advantages of the present invention and the objectives achieved by the implementation of the present invention, reference must be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described therein. The structure and operation of a preferred embodiment of the present invention will be described in detail below with reference to the attached drawings. It should be noted that in assigning reference numerals to the components of each drawing, identical components are denoted by the same numeral whenever possible, even if they are shown in different drawings. In the embodiments of the present invention described below, the vessel may be any type of vessel equipped with an engine capable of using liquefied petroleum gas as fuel for a propulsion engine or as fuel for a power generation engine. Representative examples include vessels with self-propulsion capabilities such as LPG carriers, LNG carriers, liquid hydrogen carriers, and LNG RVs (Regasification Vessels), as well as offshore structures that do not have propulsion capabilities but float on the sea, such as LNG FPSOs (Floating Production Storage Offloading) and LNG FSRUs (Floating Storage Regasification Units). Furthermore, these embodiments can be applied to fuel supply systems for all types of liquefied gases that can be transported by liquefying at low temperatures, generate evaporative gas while stored, and be supplied as fuel to an engine. Such liquefied gases may be liquefied petrochemical gases such as, for example, LNG (Liquefied Natural Gas), LEG (Liquefied Ethane Gas), LPG (Liquefied Petroleum Gas), Liquefied Ethylene Gas, and Liquefied Propylene Gas. However, in the embodiments described below, the application of LPG, which is one of the representative liquefied gases, will be used as an example. FIG. 1 schematically illustrates an LPG recovery system for a ship according to a first embodiment of the present invention, and FIG. 2 schematically illustrates an LPG recovery system for a ship according to a second embodiment of the present invention. As illustrated in FIG. 1, the LPG recovery system of the first embodiment is applied to a ship equipped with an engine (E) that receives LPG as fuel, and a fuel supply system including a service tank (T) that stores LPG to be supplied to the onboard engine and a fuel supply line (SL) that supplies LPG from the service tank to the engine. The service tank (T) stores liquid LPG and may be a pressure tank with a design pressure of 15 to 20 bar, and may be installed on the upper or lower part of the deck. LPG and N2 gas coexist in the service tank, and when the pressure exceeds 18 bar, the pressure can be partially relieved through safety valve No. 17 to regulate the internal pressure of the tank. In the fuel supply line (SL), a transfer pump (100) for transferring LPG from a service tank, a compression pump (110) for compressing the LPG transferred from the transfer pump to the required pressure of the engine, a temperature control unit (120) for heating or cooling the LPG compressed by the compression pump to the required temperature of the engine, and