Process of BOG treating in LNG receiving station with normal temperature compressor

doi:10.11949/j.issn.0438-1157.20181153

Abstract

Abstract:

A certain amount of boil-off gas (BOG) will be produced during the operation of LNG receiving station. At present, three processes of torch, compression and re-condensation are commonly used to process BOG. Due to the low temperature of BOG, the cryogenic compressor is widely used in the compression process. However, the cost of cryogenic compressor reduces the economic benefits of LNG receiving station. Therefore, this paper proposes a process for BOG treating using a normal temperature compressor. The process utilizes the high temperature BOG of the compressor outlet to heat the low temperature BOG at the inlet of the compressor. On the one hand, the inlet temperature of the compressor is increased, which makes it possible for the normal temperature compressor to replace the cryogenic compressor; on the other hand, the BOG temperature at the outlet of the compressor and the cooling capacity required for the BOG re-condensation is reduced. Both cryogenic temperature compression and normal temperature compression process are simulated by HYSYS software. The results show that the normal temperature compressor process is more advantageous for small LNG receiving stations.

摘要：

液化天然气（LNG）接收站运行过程中会产生一定量的蒸发气（BOG），目前常用火炬、压缩、再冷凝三种工艺来处理BOG。由于BOG温度较低，压缩工艺中普遍采用的是低温压缩机。然而低温压缩机造价十分昂贵，极大地降低了LNG接收站的经济效益。为此，提出了一种利用常温压缩机处理BOG的工艺。该工艺利用压缩机出口的高温BOG来加热压缩机进口处的低温BOG，一方面提高了压缩机进口温度，使得常温压缩机代替低温压缩机成为可能；另一方面，降低了压缩机出口BOG的温度，减少了BOG再冷凝所需冷量。借助HYSYS软件对低温压缩和常温压缩工艺进行了模拟分析，结果表明对于小型LNG接收站，常温压缩机工艺更有优势。

CLC Number:

TQ519

XIONG Xiaojun, HE Ting, LIN Wensheng. Process of BOG treating in LNG receiving station with normal temperature compressor[J]. CIESC Journal, 2018, 69(S2): 425-430.

熊晓俊, 何婷, 林文胜. 利用常温压缩机处理LNG接收站BOG的工艺探讨[J]. 化工学报, 2018, 69(S2): 425-430.

References

[1] LIN W S, ZHANG N, GU A Z.LNG(liquefied natural gas):a necessary part in China's future energy infrastructure[J].Energy, 2010, 35:4383-4391.
[2] 都大永, 姚红.关于LNG接收站储罐运营周转率的探索[J].国际石油经济, 2016, 24(10):86-95.DU D Y, YAO H.Exploration on the operational turnover rate of storage tanks in LNG receiving stations[J].International Petroleum Economy, 2016, 24(10):86-95.
[3] 陈行水.LNG接收站再冷凝工艺模型与动态优化[D].广州:华南理工大学, 2012.CHEN X S.Recondensation process model and dynamic optimization of LNG receiving station[D].Guangzhou:South China University of Technology, 2012.
[4] PARK C, LEE C J, LIM Y, et al.Optimization of recirculation operating in liquefied natural gas receiving terminal[J].Journal of the Taiwan Institute of Chemical Engineers, 2010, 41(4):482-491.
[5] 郭海燕, 张炜森.珠海LNG装置技术分析与运行情况[J].石油与天然气化工, 2012, 41(1):43-47.GUO H Y, ZHANG Y S.Technical analysis and operation of Zhuhai LNG plant[J].Petroleum and Natural Gas Chemical Industry, 2012, 41(1):43-47.
[6] 邓励强, 吕志军, 李宁, 等.LNG接收站再冷凝系统稳定性动态模拟研究[J].石油与天然气化工, 2016, 45(2):33-38.DENG L Q, LYU Z J, LI N, et al.Dynamic simulation of recondensation system stability of LNG receiving station[J].Petroleum and Natural Gas Chemical Industry, 2016, 45(2):33-38.
[7] QUEROL E, GONZALEZ-REGUERAL B, GARCIA-TORRENT J, et al. Boil off gas (BOG) management in Spanish liquid natural gas (LNG) terminals[J].Applied Energy, 2010, 87(11):3384-3392.
[8] 金光, 李亚军.LNG接收站蒸发气体处理工艺[J].低温工程, 2011, (1):51-56.JIN G, LI Y J.Evaporative gas treatment process at LNG receiving station[J].Cryogenic Engineering, 2011, (1):51-56.
[9] KURLE Y M, WANG S, XU Q.Simulation study on boil-off gas minimization and recovery strategies at LNG exporting terminals[J].Applied Energy, 2015, 156(1):628-641.
[10] GRANGER D.Natural gas vapor recondenser system:US6745576[P].2004.
[11] 付子航.LNG接收站蒸发气处理系统静态设计计算模型[J].天然气工业, 2011, 31(6):83-85.FU Z H.Static design calculation model of evaporative gas treatment system for LNG receiving station[J].Natural Gas Industry, 2011, 31(6):83-85.
[12] 刘浩, 金国强.LNG接收站BOG气体处理工艺[J].化工设计, 2006, 16(1):13-16.LIU H, JIN G Q.BOG gas treatment process for LNG receiving station[J].Chemical Engineering Design, 2006, 16(1):13-16.
[13] 杨志国, 李亚军.液化天然气接收站蒸发气体再冷凝工艺的优化[J].化工学报, 2009, 60(11):2876-2881.YANG Z G, LI Y J.Optimization of evaporation gas recondensation process in LNG receiving station[J].CIESC Journal, 2009, 60(11):2876-2881.
[14] LIU C, JIAN Z, QIANG X, et al. Thermodynamic-analysis-based design and operation for boil-off gas flare minimization at LNG receiving terminals[J].Industrial & Engineering Chemistry Research, 2012, 49(16):7412-7420.
[15] PARK C, SONG K, LEE S, et al.Retrofit design of a boil-off gas handling process in liquefied natural gas receiving terminals[J].Energy, 2012, 44(1):69-78.
[16] SHIN M W, SHIN D, CHOI S H, et al.Optimization of the operation of boil-off gas compressors at a liquefied natural gas gasification plant[J].Industry & Engineering Chemistry Research, 2007, 46:6540-6545.
[17] SHIN M W, SHIN D, CHOI SH, et al.Optimization of the operation of boil-off gas compression process using a boil-off rate model for LNG storage tanks[J].Korean Journal of Chemical Engineering, 2008, 25(1):7-12
[18] JANG N, SHIN M W, CHOI S H, et al.Dynamic simulation and optimization of the operation of boil-off gas compressors in a liquefied natural gas gasification plant[J].Korean Journal of Chemical Engineering, 2011, 28(5):1166-1171.
[19] LI Y J, LI Y.Dynamic optimization of the boil-off gas (BOG) fluctuations at an LNG receiving terminal[J].Journal of Natural Gas Science & Engineering, 2016, 30:322-330.
[20] 王小尚, 刘景俊, 李玉星, 等.LNG接收站BOG处理工艺优化——以青岛LNG接收站为例[J].天然气工业, 2014, 34(4):125-130.WANG X S, LIU J J, LI Y X, et al.Optimization of BOG treatment process at LNG receiving station-taking Qingdao LNG receiving station as an example[J].Natural Gas Industry, 2014, 34(4):125-130.
[21] 王文凯, 李兆慈, 盖晓峰,等.LNG接收站BOG再冷凝系统操作参数优化[J].天然气与石油, 2015, 33(2):46-52.WANG W K, LI Z C, GAI X F, et al.Optimization of operating parameters of BOG recondensing system in LNG receiving station[J].Natural Gas and Oil, 2015, 33(2):46-52.
[22] 向丽君, 全日, 邱奎, 等.LNG接收站BOG气体回收工艺改进与能耗分析[J].天然气化工(C1化学与化工), 2012, 37(3):48-50.XIANG L J, QUAN R, QIU K, et al. Improvement of BOG gas recovery process and energy consumption analysis of LNG receiving station[J].Natural Gas Chemical Industry(C1 Chemistry and Chemicals), 2012, 37(3):48-50.
[23] LI Y J, WEN M.Boil-off gas two-stage compression and recondensation process at a liquefied natural gas receiving terminal[J].Chemical Engineering & Technology, 2017, 40(1):18-27.
[24] RAO H N, WONG K H, KARIMI I A.Minimizing power consumption related to BOG reliquefaction in an LNG regasification terminal[J].Industrial & Engineering Chemistry Research, 2016, 55(27):7431-7445.
[25] KURLE Y M, WANG S, XU Q.Dynamic simulation of LNG loading, BOG generation, and BOG recovery at LNG exporting terminals[J].Computers & Chemical Engineering, 2016, 97:47-58.
[26] GÓMEZ J R, GÓMEZ M R, BERNAL J L, et al.Analysis and efficiency enhancement of a boil-off gas reliquefaction system with cascade cycle on board LNG carriers[J].Energy Conversion & Management, 2015, 94:261-274.
[27] TAN H B, ZHAO Q X, SUN N N, et al.Enhancement of energy performance in a boil-off gas re-liquefaction system of LNG carriers using ejectors[J].Energy Conversion and Management, 2016, 126:875-888.
[28] HU J Y, CHEN S, ZHU J, et al. An efficient pulse tube cryocooler for boil-off gas reliquefaction in liquid natural gas tanks[J].Applied Energy, 2016, 164:1012-1018.
[29] 王红, 白改玲, 李艳辉, 等.LNG接收站流程模拟计算[J].天然气工业, 2007, 27(11):108-109.WANG H, BAI G L, LI Y H, et al. Simulation calculation of LNG receiving station process[J].Natural Gas Industry, 2007, 27(11):108-109.
[30] LI Y J, CHEN X S, CHEIN M H.Flexible and cost-effective optimization of BOG (boil-off gas) recondensation process at LNG receiving terminals[J].Chemical Engineering Research & Design, 2012, 90(10):1500-1505.
[31] 吕俊,张昌维,傅皓.LNG接收站BOG压缩机处理能力计算及选型研究[J].化工设计, 2011, 21(1):14-16.LYU J, ZHANG C W, FU H.Calculation and selection of processing capacity of BOG compressor in LNG receiving station[J].Chemical Engineering Design, 2011, 21(1):14-16.