Seawater Utilization Research Articles

Comprehensive Utilization of Seawater in China: A Description of the Present Situation, Restrictive Factors and Potential Countermeasures

China is a maritime power. However, as its economy develops rapidly, China lacks freshwater resources. The water resources per capita are low in China and are less than a quarter of the global mean value. The development and utilization of desalination, a new unconventional water resource in coastal areas, has gradually attracted the attention of the central and local governments. This paper introduces three aspects of the comprehensive utilization of seawater in China, including the desalination of seawater, the direct use of seawater, and the use of seawater as a chemical resource. Based on the recent status (2017) of comprehensive seawater utilization in China, the prospects for optimizing the utilization of seawater resources are presented. Furthermore, the restrictive factors and potential countermeasures for the increased use of seawater desalination are investigated. Several recommendations are presented, specifically, improving the laws, using regulations and standards related to desalination, strengthening the policies that support enterprises that use desalination, gradually improving the localization rate of key technologies and equipment, and devoting additional attention to the problems associated with brine processing. Seawater is expected to become an important supplemental source of water in coastal areas of China, and the resources needed for its use will be developed as a strategic and influential industry.

A new concept for marine environmental sustainability through recovery of magnesium carbonate from traditional salt production wastewater

Environmental sustainability influenced social and economy sustainability. Without sustainably productive environment to provide resource foundation, it would difficult having sustainable society. Sustainable economy depends on sustainable raw material, energy and environmental resources. This work discussed about environmental sustainability in marine especially utilizing sea water as raw material for salt. This work started to investigate raw material characteristics and salt quality. The raw material characteristics represented high concentration for sodium, chloride, calcium and polluted by trace metal. According SEM-EDX result, salt contains lead and cooper. Salt farmer income is influenced by the salt quality, the higher its quality the bigger income received. Indirectly, economy in coastal was influenced by sea water quality. This is what encourages the research to achieve marine environmental sustainability in coastal area. The aims of this study are to review and categorize indicator for marine environmental sustainability into Driver-Pressure-States-Impacts-Response (DPSIR) and provide strategies suggestion for support environmental sustainability. DPSIR indicators are utilizing sea water, wastewater discharge into sea, increasing of sea water ion concentration, mangrove growth disruption, regulation for salt wastewater disposal direct to the sea. Recovery magnesium from salt wastewater is potential strategy to protect marine environment and to support economy-social sustainability.

Thorough conversion of CO2 through two-step accelerated mineral carbonation in the MgCl2-CaCl2-H2O system

Abstract This study describes a two-step accelerated mineral carbonation technology at moderate temperatures and atmospheric pressure by choosing the “problematic ions for seawater utilization” as mineralizers in the simplified seawater-MgCl2-CaCl2-H2O system, that is, Ca2+ as the first mineralizer and Mg2+ in the residual solution as the second. Not only can carbonate ions generated from the absorption and ionization of CO2 be fixed by Ca2+ through the first carbonation process with the added alkali source, MgO, but HCO3− in the residual solution can also be mineralized by Mg2+ through the second carbonation process. Meanwhile, pure CaCO3 and MgCO3·3H2O, which have the possible benefit of reuse, can be obtained as by-products. Then, more variables were set to optimize the technical conditions to enhance the decalcification rate and carbon sequestration ratio, reduce the reaction time during the first mineralization and attempt to realize the combination of HCO3− and Mg2+ by adding NaOH to produce MgCO3·3H2O as another by-product in a moderate environment during the second mineralization.

Soil Improvement Using MICP and Biopolymers: A Review

Ground improvement techniques provide strong natural platforms for construction activities and save the need for designing more resistant structures which would have been necessary on weak ground. This paper discusses the biogeotechnical techniques for improving the resistance of unsaturated sand dunes against surficial erosion by natural processes of wave actions and storm surges. Mechanism of microbially induced calcite precipitation (MICP) and its optimization by utilizing sea water and minimal urea usage is discussed. Common factors affecting the MICP process are briefly discussed. Biomineralization using biopolymers is also described along with the soil strengthening mechanisms. Geotechnical applications of some commonly available biopolymers are described briefly. Advantages and limitations in both these mineralization methods are analyzed and some research opportunities are pointed out for future research.

냉열발전을 위한 극저온 체크밸브의 유동해석

Abstract: Swing check valve is opened when the flow direction is forward, when the flow is reversed, the valve is automatically closed by back pressure. In this study, the internal flow field analysis of the valve was conducted by Fluent. The working fluid used in the study, using liquefied methane -165 ℃ (CH4) and velocity field, pressure field, pressure drop coefficient were simulated by varying separately the opening divergence into four intervals from 0 to 100%. The approximate research result are as follow : When the opening divergence is smaller, it appears high pressure on the upstream side, this value is relaxed when the opening divergence is large. Flow rate coefficient of the valve shows a larger value as the degree of opening becomes larger, confirming that the check valve used in the study is in the effective flow rate counting range. Key Words ：Cryogenic, LNG, Swing Check Valve, Flow Analysis, Flow Coefficient, Pressure Drop Coefficient *†문정현(교신저자) : 선박해양플랜트연구소 해수플랜트연구센터E-mail : moonjh@kriso.re.kr, Tel : 033-630-5028 *†Jung-Hyun Moon(corresponding author) : Korea Research Institute of Ships & Ocean Engineering, Seawater Utilization Plant Research CenterE-mail : moonjh@kriso.re.kr, Tel : 033-630-5028

Experimental Study on Seawater Applications in Organic Reactions

Background: Total water resources account for only 2.5% of freshwater on earth, and only 1% of total water resources can be exploited by humans. The development of practical methods of seawater desalination and comprehensive utilization technology can help address the shortage of freshwater resources in the world, and achieve sustainable use of water resources to ensure sustainable development in a society. Direct seawater utilization currently involves industrial cooling water, water for agricultural irrigation, and flushing water. Applications in aqueous phase organic reactions, particularly the direct use of seawater in industrial organic synthesis reactions, are seldom reported. Methods: we used seawater instead of freshwater in selected basic organic chemical reactions. The application of seawater in aqueous phase organic reactions was systematically investigated. Six types of reactions were studied using freshwater and seawater, namely, preparation of acetanilide, synthesis of mandelic acid, Cannizzaro reaction, Hofmann degradation reaction, preparation of quinazolin-4-one, and preparation of adipic acid. Results: Seven organic compounds were produced. Results show that some organic reactions could directly use seawater or treated seawater as an alternative to freshwater. The yields of the reactions using seawater could be compared with literature values, or were even better than literature values. Conclusion: This research provides new opportunities for the comprehensive utilization of seawater. Some organic reactions could directly use seawater or treated seawater instead of freshwater. The use of seawater instead of freshwater for organic reactions in industrial production may greatly conserve freshwater resources and protect the environment. Keywords: 3-amino-2-chloro-4-methyl pyridine, anthranilic acid, hofmann degradation, quinazolin-4-one, seawater.

Surface Modification of Anion Exchange Membrane by Covalent Grafting for Imparting Permselectivity between Specific Anions

An anion exchange membrane (AEM) embracing stable permselectivity for the specific anions is badly needed in the relevant electrodialysis process. Accordingly, a covalent modification scheme for a conventional AEM was put forward in this work, including the introduction of carboxyl groups by chemical reduction of aryl diazonium salts, the PEI immobilization by amidation reaction and then glutaraldehyde-induced PEI multilayers deposition. Firstly, the changes in the surface morphology and its chemical composition after membrane modification were investigated by scanning probe microscope and attenuated total reflection-Fourier transform infrared spectroscopy. Then, the ion exchange capacity, water content, membrane conductivity, limiting current density as well as salt permeability coefficient corresponding to different modified stages were discussed in detail. Especially, in order to simulate the possible applications in the comprehensive seawater utilization and water purification, series of electrodialysis experiments for SO42−/Cl− system were conducted for evaluating the selective separation property of the membranes after modification in terms of the permselectivity coefficient of sulfate ion against chlorine ion and the leakage rate of sulfate ion. In addition, the surface homogeneity after modification was also explored by chronopotentiometric curves and current–voltage curves. The experiment results indicated that the covalent modification scheme proposed in this study can effectively adjust the surface hydrophilicity of heterogeneous AEMs for imparting the permselectivity between the specific anions with different hydration energy and improve its surface homogeneity for ameliorating concentration polarization at the same time.

Synthesis of polyaspartic acid derivative and evaluation of its corrosion and scale inhibition performance in seawater utilization

A polyaspartic acid derivative (PASP-SEA-ASP) was synthesized from polysuccinimide with 2-aminoethanesulfonic acid and aspartic acid. PASP-SEA-ASP achieved a better corrosion inhibition rate for A3 carbon steel in seawater compared with polyaspartic acid (49% cf. 45% at the dosage of 100mg/L). The development of a composite inhibitor (a mixture of PASP-SEA-ASP, zinc sulfate, 2-hydroxyphosphonoacetic acid (HPAA) and hexadecylldimethyl (2-sulfite) ethyl ammonium on a mass ratio of 15:3:6:1, respectively) led to a significantly enhanced corrosion inhibition effect, achieving an inhibition rate of 97%. The mass ratio of the composite inhibitor could be adjusted to achieve the desired corrosion inhibition rate for seawater with varying characteristics. PASP-SEA-ASP also showed excellent scale inhibition properties for seawater, with a scale inhibition rate of 100% achieved with a dosage of 14mg/L. This study demonstrated the potential of PASP-SEA-ASP to inhibit both corrosion and scale formation in domestic and industrial utilization of seawater such as cooling systems and thermal desalination processes.

Bioleaching of copper secondary sulfide ore in the presence of chloride by means of inoculation with chloride-tolerant microbial culture

Mining faces today an enormous challenge in terms of the limited availability of water resources. This is especially significant for bioleaching operations where not only the accessibility but also the water quality can be critical for the successful treatment and processing of minerals. Bioleaching circuits may even require the implementation of bleed or purge systems in order to manage impurities, like chloride for example, at adequate levels for microbial activity, therefore increasing water consumption. This study evaluates the alternative of bioleaching copper secondary sulfide ores in high chloride systems (resulting in increased process water recirculation in chloride-rich ore systems or as result of seawater utilization) by means of an adapted chloride and copper-tolerant mixed culture. A chalcocite-rich ore was bioleached in columns under different concentrations of chloride. The chloride-tolerant culture consisted of a mixed of Acidithiobacillus thiooxidans-like strain and Leptospirillum ferriphilum strain Sp-Cl (DSM 22399). High redox potentials and complete ferrous iron oxidation was achieved in all columns up to 6g/L Cl− reaching good copper extractions (from 79.5 to 83.3%) comparable to low-chloride bioleaching systems. The microbial population on the ore phase was predominantly represented by A. thiooxidans-like strain in contrast to the column effluents where Leptospirillum strain Sp-Cl was the dominant microorganism.These results represent a significant example that biologically assisted leaching of secondary sulfide copper ores in the presence of moderate chloride is achievable and supports the possibility to incorporate the use of seawater, as a proportion of the global water make-up, as well as the increase of process water recirculation in industrial operations.

An attempt for improving electrodialytic transport properties of a heterogeneous anion exchange membrane

In this work, glutaraldehyde-induced poly(ethyleneimine) (PEI) multilayer deposition was attempted with the aim to improve the electrodialytic transport properties of a heterogeneous anion exchange membrane (AEM), including selective separation between specific anions and amelioration of concentration polarization. Firstly, the change of surface hydrophilicity and morphology after modification were investigated by contact angle measurement and scanning probe microscope observation. Then, the electrodialytic transport properties were comprehensively evaluated by the measurements of salt permeability coefficient, permselectivity of counter-ions, membrane electrical resistance and limiting current density. Especially, in order to simulate the possible applications in the seawater utilization and groundwater purification, two kinds of systems such as Cl−/SO42− system and F−/Cl− system were chosen to estimate and compare the selective separation properties of the membranes. Furthermore, the alteration of surface heterogeneity after modification was understood by chronopotentiometric and current–voltage curves. The experimental results showed that PEI multilayers formed by covalent layer-by-layer assembly can effectively adjust the surface hydrophilicity and improve the surface homogeneity of heterogeneous AEM at a slight sacrifice of membrane conductance. Thereupon, the selective separation between the anions with different hydration energy can be achieved. The improvement of surface homogeneity can contribute to the amelioration of the concentration polarization during a electrodialysis process.

Marine Environment Impact Analysis and Countermeasures on Sea Water Utilization Project

Sea water utilization projects are catching attention as the seawater utilization industry continues to grow. This paper analyzes the marine environment impact from different kind of sea water utilization projects such as seawater desalination, direct seawater utilization and seawater chemical resource extraction, and brieflypresents relevant countermeasures.

해수전착 코팅을 이용한 내부식성 철근의 개발 및 적용성에 대한 연구 (1) -해수전착 코팅 시스템 개발

본 연구는 해수에 존재하는 다량의 칼슘 및 마그네슘 이온을 전기적으로 강판에 전착하는 전착시스템을 개발하는 것이다. 최종적인 목표는 해수를 이용하여 전착한 구조용 철근의 개발이며, 본 연구는 1단계 연구로서 고내구성 철근개발을 위한 전착시스템 개발에 목적을 두었다. 다양한 전극과 온도, 전류밀도, 코팅시간 등을 변수로 하고 실험을 수행하여 철근 코팅을 위한 최적의 조건을 도출하였다. 탄산칼슘(<TEX>$CaCO_3$</TEX>)과 수산화마그네슘(<TEX>$Mg(OH)_2$</TEX>)으로 구성된 코팅층은 SEM, EDS, XRD 등을 통하여 성분을 파악하였으며, 자연전위 및 전류밀도를 분석하여 기존의 철보다 부식에 대하여 매우 안전함을 확인하였다. 본 연구의 성과를 이용하여 고내구성 강재의 구조적, 내구적 실험에 대한 토의가 2차 연구에서 추가적으로 수행될 것이다. This study is for developing a system for electro-deposition utilizing sea water containing various ions like calcium and magnesium. This is the first step research for the final goal which is a development of anti-corrosive steel for RC structure, so that this paper is mainly focused on the development for electro-deposition system. Optimum conditions for steel coating is obtained through various tests considering anode type, temperature, duration time, and current density. The composition of electro-deposition is analyzed through SEM, EDS, and XRD and it is evaluated to be <TEX>$CaCO_3$</TEX> and <TEX>$Mg(OH)_2$</TEX>. Through measuring polarization potential and current density in the coated steel, the coating layer from the developed system is evaluated to have high resistance to steel corrosion. Additional tests and discussions on durability and structural performance in the coated steel from this work will be performed for the second step research.

Enhancement of LNG plant propane cycle through waste heat powered absorption cooling

In liquefied natural gas (LNG) plants utilizing sea water for process cooling, both the efficiency and production capacity of the propane cycle decrease with increasing sea water temperature. To address this issue, several propane cycle enhancement approaches are investigated in this study, which require minimal modification of the existing plant configuration. These approaches rely on the use of gas turbine waste heat powered water/lithium bromide absorption cooling to either (i) subcool propane after the propane cycle condenser, or (ii) reduce propane cycle condensing pressure through pre-cooling of condenser cooling water. In the second approach, two alternative methods of pre-cooling condenser cooling water are considered, which consist of an open sea water loop, and a closed fresh water loop. In addition for all cases, three candidate absorption chiller configurations are evaluated, namely single-effect, double-effect, and cascaded double- and single-effect chillers. The thermodynamic performance of each propane cycle enhancement scheme, integrated in an actual LNG plant in the Persian Gulf, is evaluated using actual plant operating data. Subcooling propane after the propane cycle condenser is found to improve propane cycle total coefficient of performance (COPT) and cooling capacity by 13% and 23%, respectively. The necessary cooling load could be provided by either a single-effect, double-effect or cascaded and single- and double-effect absorption refrigeration cycle recovering waste heat from a single gas turbine operated at full load. Reducing propane condensing pressure using a closed fresh water condenser cooling loop is found result in propane cycle COPT and cooling capacity enhancements of 63% and 22%, respectively, but would require substantially higher capital investment than for propane subcooling, due to higher cooling load and thus higher waste heat requirements. Considering the present trend of short process enhancement payback periods in the natural gas industry, subcooling propane after the propane cycle condenser is recommended as the preferred option to boost propane cycle performance.

Sustainable management of urban water resources in China

Due to the rapid development of economy, China has been facing severe water shortage and water pollution problems. This paper discusses three strategies developed for the urban water resource management in China, which is essential for the sustainable development of its economy. These strategies include setting high priority for demand control and water conservation, controlling pollution from the sources and increasing investment for wastewater treatment; and developing untraditional water resources, such as rainwater harvesting, wastewater reclamation, seawater utilization, etc. It is hoped that these strategies may not only solve the water shortage and water pollution problems at low capital and operational costs, but also meet the present and future needs on water resources in China.

Effects of utilizing seawater as a cooling source system in a commercial complex

This paper treats energy and cost performance of a cooling source system with indirect seawater utilization for air conditioning in a commercial complex. Seawater utilization has merits as a cooling source, because seawater temperature is lower than outdoor air in summer and it is cost effective because there is no water monetary cost. Actual operating data has been measured for about 2 years and the chiller and system co-efficient of performance (COP) have indicated about 4.77 and 2.93, respectively, even in summer season and the mean efficiency of the thermal storage system was about 89.9% taking into account heat loss of pumps. In addition, we have constructed simulation models for cooling tower systems, air cooling chiller systems and direct seawater utilization systems then compared them to this system. The electric power consumption of the indirect seawater utilization system was almost the same as the other systems except the air cooling chiller system, because using lower seawater temperature made the chiller efficiency higher. In conclusion, our results showed the indirect seawater utilization system was able to improve the system COP compared to air cooling chiller system, and cancel water consumption compared with the cooling tower system, and cut down an initial and maintenance costs compared with the direct seawater utilization system.

449 海水利用高効率ヒートポンプシステム : 名古屋港水族館のプール水温調節(冷媒物性およびヒートポンプ,環境保全型エネルギー技術)

The temperature of sea water is lower than the outside air temperature in summer, and higher than the outside air temperature in winter. Therefore, high energy efficiency can be obtained by utilizing sea water for heat source water or cooling water of heat pumps. Then, we had developed the highly effective heat pump, which can use sea water directly as heat source or cooling water. In the Port of Nagoya Public Aquarium, the water temperature of huge pools for breeding orca, belugas, etc., is adjusted with this highly effective heat pump system. In this paper, the energy-saving performance and environmental preservation performance of the system are clarified by analyzing the operation data over a period of four fiscal years.

Effects of hot deep seawater bathing on the immune cell distribution in peripheral blood from healthy young men

Deep seawater (DSW) utilization technology has been developed for the fields of medicine and health, among others. To clarify the health effects of DSW as compared with surface seawater (SSW) or tap water (TW), we investigated the changes of immune cell distribution of the peripheral blood, or subjective judgment scores, after hot water bathing. Ten healthy young men were immersed for 10 min in DSW, SSW and TW heated to 42°C. Blood samples were collected before bathing, immediately after bathing and 60 min after bathing. Total and differential numbers of leucocytes and lymphocyte subsets (CD3, CD4, CD8, CD19, CD16, and CD56) were examined using an automated hematology analyzer and a flow cytometer, respectively. The subjective judgment scores were obtained by an oral comprehension test. Since the pre-bathing leukocyte count in the TW group was significantly different from those in the DSW and SSW groups, we excluded the findings of TW bathing from consideration. In hot DSW bathing, CD8-lymphocytes increased significantly immediately after bathing (p<0.05), in contrast to hot SSW bathing, in which no significant changes were detected in the lymphocyte subsets. Additionally, there were no significant changes between repeated measurements in the subjective judgment scores, though the score of thermal sensation in SSW bathing showed a significantly higher value immediately after bathing than before bathing (p<0.01). Our findings suggest that increased CD8-lymphocytes in hot DSW bathing may improve human immune function as well as hot springs do, as compared with SSW bathing. Although hot DSW bathing may have the ability to change human immune cell distribution, well-designed studies are needed to clarify the health effects including not only DSW and SSW but also TW.

Energy and Cost Performance of a Cooling Plant System with Indirect Seawater Utilization for Air-Conditioning in a Commercial Building

This paper presents energy and cost performance of a cooling plant system with indirect seawater utilization for air-conditioning in a commercial building. The energy and cost performance is verified by direct measurement and a model-based simulation analysis. In the simulation, the indirect seawater utilization system is compared with a cooling tower system, an air source heat pump chiller system and a direct seawater utilization system. The electric energy consumption of the indirect seawater utilization system is almost the same as the other systems except the air source heat pump chiller system, because using lower seawater temperature can make the efficiency of the refrigerating machine higher, but this system also needs electric energy for cooling seawater/freshwater pumps. However, the indirect seawater utilization system can largely reduce demand charge compared with the cooling tower system, and cut down initial and maintenance costs compared with the direct seawater utilization system. Using these results, the effectiveness of the indirect seawater utilization system toward environmental conservation, energy and cost reduction is clarified in this paper.

閉鎖性海域の水質浄化への海洋深層水の利用について

As a study of deep seawater utilization, application for possible improvement of seawater quality in an enclosed harbor area was examined by a numerical analysis. The effect of direct discharge of deep seawater is compared with that of surface water discharge. Although deep seawater turned out to be more effective than the surface water, rather large discharge at least 100, 000m3/day was required to achieve a significant improvement of water quality. As an another possible improvement of water quality using deep seawater, nutrient absorption by seaweed community in the enclosed area was evaluated.

Flounder Culture and Its Challenges in Asia

Japanese flounder, Paralichythys olivaceus, is a temperate marine species cultured in coastal areas of Japan, Korea, and China. Recent annual production is roughly estimated to be 28,000 metric tons (MT) in these areas. Flounder culture is totally dependent on the supply of artificially produced juveniles, and is mostly done in flowthrough systems. Japan developed and established the seed production technology of this species. Until the 1980s, flounder was cultured only in Japan, but through the transfer of technologies from Japan to Korea, and then China, production has increased rapidly. Products are distributed as live fish and consumed as raw fish, or “sashimi”, at a relatively high price. Flounder culture has suffered from the outbreak of various diseases, together with a decreased demand in its niche market. Closed recirculating systems and deep seawater utilization should be considered as countermeasures to reduce the cost and improve the quality in the future.