Conceptual design and exergy analysis of combined cryogenic energy storage and LNG regasification processes: Cold and power integration

Lee, Inkyu,Park, Jinwoo,Moon, Il Pergamon Press 2017 Energy Vol.140 No.1

<P><B>Abstract</B></P> <P>This study aims to develop an efficient cryogenic energy storage (CES) process using the exergy from liquefied natural gas (LNG) regasification. While LNG has low internal energy, it has high exergy because of its cryogenic characteristics, and much of this exergy is wasted in the process of regasification. Thus, this work focuses on the recovery of LNG cold exergy to store cryogenic energy using air as a working fluid. The cold exergy of LNG is transferred in two forms: cold transfer by heat exchange to liquefy air, and shaft work transfer by direct expansion of LNG to compress the air. Thermodynamic analysis of the proposed process is carried out in three exergy flow steps: the LNG regasification step, the air liquefaction step, and the air expansion step. In addition, the proposed system has an advantage which system can store and release the energy simultaneously. Therefore, daily produced energy by CES system is more than double compare to the most recent contributions that have divided operation modes for energy storage and release. This study not only proposes an efficient energy storage process that can generate power flexibly but also highlights further possibilities for performance enhancement by thermodynamic analysis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The integrated Cryogenic energy storage (CES) and liquefied natural gas (LNG) regasification process is proposed. </LI> <LI> Exergy efficiency of the air storage process is 94.2%, and the air release process is 61.1%. </LI> <LI> The specific power output per 1 kg of LNG is about 160.92 kJ. </LI> </UL> </P>

A novel cryogenic energy storage system with LNG direct expansion regasification: Design, energy optimization, and exergy analysis

Lee, Inkyu,Park, Jinwoo,You, Fengqi,Moon, Il Elsevier 2019 ENERGY Vol.173 No.-

<P><B>Abstract</B></P> <P>Recovering the remaining cold energy from the regasification process is one of the key challenges of the overall LNG value chain. This paper aims to develop a cryogenic energy storage system (CES) integrated with LNG direct expansion regasification (LNG–CES) that can recover cold energy and store it as cryogenic energy using air as the working fluid. Cold energy of LNG is available in two forms: thermal energy by heat exchange and shaft work by expansion, while the cryogenic storage process requires compression and cooling. The supply and demand of LNG direct expansion and cryogenic energy storage processes are well balanced. Therefore, a combined LNG–CES process to store energy will prove efficient. This study proposes an industrial-feasible design for the LNG–CES process and energy optimization to maximize net power output from the process. Moreover, a novel process design is proposed to recover cold energy lost during LNG regasification more efficiently. Energy optimization results of the proposed design demonstrated an 11.04% increase in the net power generation from the feasible configuration of the base design. Additionally, the cause of this improvement was studied using thermodynamic analyses.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A feasible design of cryogenic energy storage process with LNG regasification. </LI> <LI> A novel design for efficient air sub-cooling via two-stage LNG pressurization. </LI> <LI> A thermodynamic based optimization to maximize net power output. </LI> </UL> </P>

해수-LNG 재기화열을 이용한 온도차발전 시스템 최적화

문정현(Junghyun Moon),이호생(Hosaeng Lee),임승택(Seungtaek Lim),서종범(Jongbeom Seo),김현주(Hyeonju Kim) 한국해양환경·에너지학회 2021 한국해양환경공학회 학술대회논문집 Vol.2021 No.5

전력케이블이 도달하지 않는 도서국가와 도서지역에서는 해당지역의 전력 수급을 위해 주로 디젤 발전기를 사용한다. 국내 대기환경보전법에서는 내연기관에서 연료 연소에서 발생하는 미세먼지와 SOx, NOx의 배출 저감을 위해 후처리를 필요로 하나 도서지역에 한해 후처리장치 없이 운영할 수 있는 예외 조항이 있어(1.5MW 규모 이하 해당) 도서지역 디젤발전기의 대기오염 발생, 연료 운반 중 유출 우려 등 환경오염 관련한 다양한 문제가 있다. 이러한 문제 해결을 위해 도서지역 전기 생산을 위한 연료를 LNG로 대체하고자 하는 연구와 장비의 보급이 진행되고 있으며, 별도의 LNG 터미널이 없이도 운반된 LNG를 기화할 수 있도록 소형 LNG 기화장치, 소형 FSRU 등의 제작 및 보급이 증가하는 추세이다. 본 연구에서는 해수를 열원으로, LNG의 기화열을 열침으로 이용하는 온도차발전 시스템을 구성하였다. 작동유체의 증발압력을 변수로 시스템의 성능을 분석하였으며, 기생부하를 고려한 순출력의 최적화를 진행하였다. In island countries and island regions where power cables do not reach, diesel generators are mainly used to supply power to the region. The domestic Air Environment Conservation Act requires post-treatment to reduce the emission of fine dust, SOx, and NOx generated from fuel combustion in internal combustion engines. But as there is an exception clause that can be operated without an post-treatment system(for less than 1.5MW scale) only in island regions, there are various problems related to environmental pollution, such as air pollution from diesel generators in islands, and concerns about spills while transporting fuel. In order to solve this problem, research and equipment are being distributed to replace fuel for electricity production in islands with LNG. For example, the production and supply of small LNG vaporizers and small FSRUs so that transported LNG can be vaporized without a separate LNG terminal is increasing. In this study, an ORC system was constructed that uses seawater as a heat source and LNG vaporization heat as a heat sink. The system performance was analyzed using the evaporation pressure of the working fluid as a variable, and the net power was optimized considering the parasitic load.

Research of design challenges and new technologies for floating LNG

이동현,하문근,김수영,신성철 대한조선학회 2014 International Journal of Naval Architecture and Oc Vol.6 No.2

With the rate of worldwide LNG demand expected to grow faster than that of gas demand, most major oil companies are currently investing their resources to develop floating LNG-FLNG (i.e. LNG FSRU and LNG FPSO). The global Floating LNG (FLNG) market trend will be reviewed based on demand and supply chain relationships. Typical technical issues associated with FLNG design are categorized in terms of global performance evaluation. Although many proven technologies developed through LNG carrier and oil FPSO projects are available for FLNG design, we are still faced with several technical challenges to clear for successful FLNG projects. In this study, some of the challenges encountered during development of the floating LNG facility (i.e. LNG FPSO and FSRU) will be reviewed together with their investigated solution. At the same time, research of new LNG-related technologies such as combined containment system will be presented.

Research of design challenges and new technologies for floating LNG

Lee, Dong-Hyun,Ha, Mun-Keun,Kim, Soo-Young,Shin, Sung-Chul The Society of Naval Architects of Korea 2014 International Journal of Naval Architecture and Oc Vol.6 No.2

With the rate of worldwide LNG demand expected to grow faster than that of gas demand, most major oil companies are currently investing their resources to develop floating LNG-FLNG (i.e. LNG FSRU and LNG FPSO). The global Floating LNG (FLNG) market trend will be reviewed based on demand and supply chain relationships. Typical technical issues associated with FLNG design are categorized in terms of global performance evaluation. Although many proven technologies developed through LNG carrier and oil FPSO projects are available for FLNG design, we are still faced with several technical challenges to clear for successful FLNG projects. In this study, some of the challenges encountered during development of the floating LNG facility (i.e. LNG FPSO and FSRU) will be reviewed together with their investigated solution. At the same time, research of new LNG-related technologies such as combined containment system will be presented.

신계념 LNG-RV 운반선의 현황

배병덕 한국항해항만학회 2007 한국항해항만학회 학술대회논문집 Vol.2 No.추계

최근 엘엔지운반선(LNGC)은 선체의 대형화, DFDE디젤엔진탑재, 재액화설비등의 변화와 함께 해상터미널의 역할을 동시에 할 수 있는 LNG-RV(Regasification Vessel)의 출현을 경험하였으며, 이러한 신계념의 선박의 개발개념, 운항방식 등에 대하여 살펴보도록 한다.

극저온용 PCHE 내 프로판의 응축성능에 대한 실험적 연구

류진우(Jin Woo Yoo),남찬우(Chanwoo Nam),신정헌(Jeong-Heon Shin),김동호(Dong Ho Kim),윤석호(Seok Ho Yoon) 대한설비공학회 2020 대한설비공학회 학술발표대회논문집 Vol.2020 No.6

Analysis on Design Concept of LNG Regasification System

Sojung Kim,Kiil Nam,Jaesu Kim 한국해양환경·에너지학회 2012 한국해양환경공학회 학술대회논문집 Vol.2012 No.5

In this paper, we suggest a basic system composition requirement, and discuss the general design conditions of regasification systems. Regasification systems were designed and simulated in HYSYS to compare the energy use of the systems. This paper also demonstrates the operability of regasification system between regasification system and cargo handling system.

1P-582 간접가열식 LNG 재기화 시스템을 위한 폐회로 공정 개발 및 에너지 소비 분석

김준영,이춘식,윤문규,염충섭 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

LNG 재기화 시스템은 액체 상태로 저장된 액화천연가스(LNG)를 기체 상태로 변환하는 LNG FSRU(Floating Storage and Regasification Unit)의 핵심 설비이다. LNG 재기화 시스템은 열교환 방식에 따라 직접가열식 공정(해수 자체열을 이용한 공정)과 간접가열식 공정(글라이콜, 프로판, 부탄 등의 열전달 매체를 이용한 공정)으로 구분되며, 최근에는 국제사회에서의 해수 사용 제한 규제(냉각된 해수 배출로 인한 생태계 교란)와 지역 및 계절에 따른 해수 온도 편차로 인해 간접가열식 공정이 보편화되고 있다. 이에 따라 본 연구에서는 산업의 수요에 발맞춰 간접가열식 공정 중에서 프로판 냉매를 이용한 폐회로(Closed Loop) 공정을 개발하였다. 또한, 이 공정의 에너지 소비량을 간접가열식의 대표 공정인 개회로(Open Loop) 공정과 비교 분석함으로써, 에너지 효율을 확인하였다. ^**본 연구는 산업통상부의 재원으로 한국산업기술평가관리원(KEIT)의 지원을 받아 수행되었음(No. 10067761).

Exergoeconomic analysis of an LNG integrated - air separation process

Hamayun Muhammad Haris,Ramzan Naveed,Faheem Muhammad 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.12

An integrated LNG regasification - air separation process is investigated using exergy and exergoeconomic analyses. The objective of developing this integrated process is to lower the calorific value of LNG by mixing regasified LNG with high purity nitrogen, while simultaneously recovering and utilizing valuable cryogenic energy from the LNG during its regasification to minimize the power consumption of the air separation unit (ASU) for nitrogen production. The overall exergy efficiency and exergy destruction of the integrated process are 76.47% and 28.52MW, respectively, with the compression section causing the most exergy destruction. Further exergoeconomic analysis of the proposed process reveals that the air compressors have the highest capital investment (CI) and operating and maintenance (O&M) cost rates, the pumps for cooling water and LNG have the highest exergoeconomic factors, and the low-pressure column and a multistream heat exchanger have the highest exergy destruction cost rates. A parametric study is also conducted to examine the impact of economic variables including interest rate, plant life, and compressor performance on exergy destruction, CI and O&M cost rates, and exergoeconomic factor. The findings of this study offer valuable insight into the design and optimization of similar integrated processes, with potential benefits for the energy industry.