• Journal of Advanced Marine Engineering and Technology
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• 제27권7호
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• pp.839-844
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• 2003

As sea water is being used as only heat source of LNG open rack vaporizer, serious problem has been risen in LNG terminal by the lack of heating energy source for LNG vaporization due to the temperature drop of sea water in winter. In this paper the new double-tube triple-flow(TRIDEX) vaporizer was suggested to solve the problem and the system was thermally analysed. LPG(liquefied petroleum gas) and sea water were introduced as the heat sources for LNG TRIDEX vaporizer. The flow patterns of TRIDEX vaporizer are as follows: LNG flow in the annular space, PG(petroleum gas) flow in the inner tube, and sea water flow in the outside of the double pipe. The overall LNG vaporization system was consisted of TRIDEX vaporizer, LPG vaporizer and PG heater. LPG in TRIDEX was directly dispersed in the sea water desalination unit, so that LPG turns to be gas phase for the reuse in TRIDEX vaporizer. New TRIDEX vaporizer system for LNG evaporation was analysed as much more effective than the present single tube one in the case of colder temperature of sea water in winter.

• 상하수도학회지
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• 제12권3호
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• pp.48-54
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• 1998

Korea becomes one of the countries which suffer from water shortage. It is expected that its water shortage in the early 2000's will be more than 10% of the annual demand. The shortage problem is more serious in the coastal areas where many industry complex locate. To solve the shortage problem, seawater desalination gets more attention as an alternative water supply source since Korea is surrounded by sea on its three sides. For potential application of seawater desalination in Korea, an economic analysis was conducted using cost data for the plants in the Middle Ease areas, The United states and others. The study is to provide a basis for the government to establish a strategy for promoting seawater desalination in Korea. It is discussed that the Reverse Osmosis (RO) process gets cheaper over times than the thermal processes of Multi-stage Flash Distillation (MSF) and Multi Effect Distillation (ME), especially in case where the capacity is less than about 50,000 ton/day. The unit cost of RO seawater is analyzed about US$1.35/ton in 1990 price. Since the Desalination plant can be operated regardless of weather conditions, industries in Korea's coastal areas which suffer from frequent droughts and water shortages are recommended to look into this option with more attention.

• 한국수자원학회논문집
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• 제49권5호
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• pp.431-438
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• 2016

역삼투 해수 담수화 공법의 주요 단점으로 여겨지고 있는 에너지 소비량을 줄이기 위한 방편으로 해안선을 통하여 바다로 유출되는 담수 지하수를 활용하여 낮은 염도의 원수를 확보하는 방안을 제시하였다. 저 염도 지하 염수는 담수화 비용 뿐 아니라 표류 해수 취수의 알려진 단점을 극복하는 데도 유리하다. 지하 염수의 염도는 해안선을 통하여 바다로 유출되는 담수 지하수량의 영향을 크게 받는다. 본 연구에서는 담수화 시설에 필요한 수량을 최저 염도로 충족시킬 수 있는 지하 염수 관정의 위치 및 양수량 분포를 산정할 수 있는 최적 전산설계모델을 개발하였다. 해안 지역에서 지하 염수를 개발하면 대수층으로 해수가 추가 침투하여 다른 사용자의 지하수 관정을 오염시킬 수 있다. 본 모델은 지하 염수 관정의 최적 설계 시에 기존 지하수 관정을 해수 침투로부터 보호할 수 있도록 구성되었다.

• Membrane and Water Treatment
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• 제8권3호
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• pp.279-292
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• 2017

This study was aimed at ultrafiltration (UF) as a pretreatment before reverse osmosis (RO) within the scheme of hybrid reverse osmosis-multistage flush (RO-MSF) desalination. Seawater at elevated temperature (after MSF heat-exchangers) was used as a feed in this process. The pretreatment system was represented as a set of functionally-linked technological segments such as: UF filtration, backwashing, chemical- enhanced backwashing, cleaning, waste disposal, etc. The process represents the sequences of operating cycles. The cycle, in turn, consists of the following unit operations: filtration, backwashing and chemical-enhanced backwashing (CEB). Quantitative assessment was based on the following indicators: normalized permeability, transmembrane pressure, specific energy and water consumption, specific waste generation. UF pre-treatment is accompanied by the following waste streams: $W1=1.19{\times}10$ power of $-2m^3$ (disposed NaOCl with 0.0044% wt.)/$m^3$ (filtrate); $W2=5.95{\times}10$ power of $-3m^3$ (disposed $H_2SO_4$ with 0.052% wt.)/$m^3$(filtrate); $W3=7.26{\times}10$ power of $-2m^3$ (disposed sea water)/$m^3$ (filtrate). Specific energy consumption is $1.11{\times}10$ power of $-1kWh/m^3$ (filtrate). The indicators evaluated over the cycles with conventional (non-chemical) backwashing were compared with the cycles accompanied by CEB. A positive impact of CEB on performance indicators was demonstrated namely: normalized UF resistance remains unchanged within the regime accompanied by CEB, whereas the lack of CEB results in 30% of its growth. Those quantitative indicators can be incorporated into the target function for solving different optimization problems. They can be used in the software for optimisation of operating regimes or in the synthesis of optimal flow- diagram. The cycle characteristics, process parameters and water quality data are attached.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 추계 총회 및 학술발표회
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• pp.11-14
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• 1998

1. Introduction : Research progresses in Chemistry and Chemical Engineering have been made during the last decades with important contributions to the industrial development and to the quality of our life. An interesting case is related to the membrane science and technology continuous impact to innovative processes and products, particularly appropriate for a sustainable industrial growth. Membrane operations have been familiar for many years to biologists and chemists working in their laboratorier or studying biological phenomena. Only recently engineers started to operate in' this area. The preparation of asymmetric CA membranes at University of California, Los Angeles in the early 60s is generally recognized as a crucial moment for membranology (1). Loeb and Sourirajan with their discovery of how to increase significantly the permeability of polymeric membranes without significant changes in their selectivity, made realistic the possibility of their use in large scale operations for desalting brackish and sea water by reverse osmosis and for various other molecular separations in different industrial areas. Reverse osmosis is today a well recognized basic unit operations, togheter with ultrafiltration, crossflow microfiltration,. nanofiltration, all pressure driven membrane processes. Already in 1992 more than 4 milIions m$^3$/day were the total capacity of RO desalination plants and in 1995 more than 180.000 m$^2$ of ultrafiltration membranes were installed for the treatment of wheys and milk (2) (3).