• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2007.05a
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• pp.83-125
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• 2007

Increasing energy costs have caused profitability problems for paper suppliers. Therefore unprofitable lines are being closed down. The actions aiming for improved profits are focused either on cost savings or on increasing the capacity of the remaining machines. The runnability of a paper machine and its total efficiency have a significant effect on energy consumption. Producing one ton of waste paper consumes at least as much energy as producing the same amount of sellable end product. New automation solutions enable significant cost-effective improvements to the total efficiency of a line without large investment projects. The measures focus on minimizing changes, interruptions, interruption recovery times and grade change times. Newest actuators, online quality measurements and wet end analysators create an improvement potential, which can be optimally implemented with the latest machine direction control solutions, based on model predictive control concepts. Equally, drying management is significant to the energy consumption. The newest control strategies optimize the use of various drying actuators for different situations; either by responding to changes as efficiently as possible or by using only the cheapest energy sources in stable situations. An even steam supply, which is vital for paper machines, is achieved with control for the power plant steam network. This makes possible to avoid the delays upon starting the paper machine and assure an even steam supply for the drying section and the actuators. This document describes means which have brought significant energy and raw material savings for paper machines. Metso Automation has provided efficiency improvement packages, which are usually based on optimized control of dry weight and drying in all running conditions. The solutions are based on performance analysis, on which the estimations for improvement potential and the necessary actions are based on. Typically benefits on an annual level have been from hundreds of thousands of euros to over one million euro. For example, variations in dry weight have been decreased more than 50%. The results are presented with a few examples. Additionally, the analysis models, adjustment solutions and the changes in running methods with which the results were achieved, are presented.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.2
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• pp.163-169
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• 2015

In many nuclear power plant sites in Korea, high density storage racks were installed in the spent fuel pool to expand the spent fuel storage capacity. Nevertheless, the capability of the Hanbit nuclear site will be saturated by 2024. Also, 10 NPPs will reach their design life expiration date by 2029. In the case of the US, SFPI (Spent Fuel Pool Island) operated temporarily as a spent fuel storage option before spent nuclear fuels were transported to an interim storage facility or a final disposal facility. As a spent fuel storage option after shutdown during decommissioning, the SFPI concept can be expected to have the following effects: reduced occupational exposure, lower cost of operation, strengthened safety, and so on. This paper presents a case study associated with the regulations, operating experiences, and systems of SFPI in the US. In conclusion, the following steps are recommended for applying SFPI during decommissioning in Korea: confirmation of design change scope of SFPI and expected final cost, the submission of a decommissioning plan which is reflected in SFPI improvement plans, safety assessment using PSR, application of an operating license change for design change, regulatory body review and approval, design change, inspection by the regulatory body, education and commissioning for SFPI, SFPI operation and periodic inspection, and dismantling of SFPI.

• Journal of Appropriate Technology
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• v.7 no.2
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• pp.136-143
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• 2021

Pacific island countries, including Kiribati, are suffering from a shortage of essential resources as well as a reduction in their living space due to sea level rise and coastal erosion from climate change, groundwater pollution and vegetation changes. Global activities to solve these problems are being progressed by the UN's efforts to implement SDGs. Pacific island countries can adapt to climate change by using abundant marine resources. In other words, seawater plants can assist in achieving SDGs #2, #6 and #7 based on SDGs #14 in these Pacific island countries. Under the auspice of Korea International Cooperation Agency (KOICA), Korea Research Institute of Ships and Ocean Engineering (KRISO) established the Sustainable Seawater Utilization Academy (SSUA) in 2016, and its 30 graduates formed the SSUA Kiribati Association in 2017. The Ministry of Oceans and Fisheries (MOF) of the Republic of Korea awarded ODA fund to the Association. By taking advantage of seawater resource and related plants, it was able to provide drinking water and vegetables to the local community from 2018 to 2020. Among the various fields of education and practice provided by SSUA, the Association hope to realize hydroponic cultivation and seawater desalination as a self-support project through a pilot project. To this end, more than 140 households are benefiting from 3-stage hydroponics, and a seawater desalination system in connection with solar power generation was installed for operation. The Association grows and supplies vegetable seedlings from the provided seedling cultivation equipment, and is preparing to convert to self-support business from next year. The satisfaction survey shows that Tarawa residents have a high degree of satisfaction with the technical support and its benefits. In the future, it is hoped that SSUA and regional associations will be distributed to neighboring island countries to support their SDGs implementations.

• Korean Journal of Environmental Agriculture
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• v.19 no.5
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• pp.401-418
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• 2000

1. Production of the artificial zeolite from coal ash Coal fly ash is mainly composed of several oxides including $SiO_2$ and $Al_2O_3$ derived from inorganic compounds remained after burning. As minor components, $Fe_2O_3$ and oxides of Mg, Ca, P, Ti (trace) are also contained in the ash. These components are presented as glass form resulting from fusion in the process of the combustion of coal. In other word, coal ash may refer to a kind of aluminosilicate glass that is known to easily change to zeolite-like materials by hydrothermal reaction. Lots of hot seawater is disposing near thermal power plants after cooling turbine generator periodically. Using seawater in the hydrothermal reaction caused to produce low price artificial zeolite by reduction of sodium hydroxide consumption, heating energy and water cost. As coal ash were reacted hydrothermally, peaks of quartz and mullite in the ash were weakened and disappeared, and new Na-Pl peaks were appeared strengthily. Si-O-Si bonding of the bituminous coal ash was changed to Si-O-Al (and $Fe^{3+}$) bonding by the reaction. Therefore the produced Na-Pl type zeolite had high CEC of 276.7 $cmol^+{\cdot}kg^{-1}$ and well developed molecular sieve structure with low concentration of heavy metals. 2. Utilization of the artificial zeolite in agro-environment The artificial zeolite(1g) could remove 123.5 mg of zinc, 164.7 mg copper, 184.4 mg cadmium and 350.6 mg lead in the synthetic wastewater. The removability is higher 2.8 times in zinc, 3.3 times in copper, 4.7 times in cadmium and 4.8 times in lead than natural zeolite and charcoal powder. When the heavy metals were treated at the ratio of 150 $kg{\cdot}ha^{-1}$ to the rice plant, various growth inhibition were observed; brownish discoloration and death of leaf sheath, growth inhibition in culm length, number of panicles and grains, grain ripening and rice yield. But these growth inhibition was greatly alleviated by the application of artificial zeolite, therefore, rice yield increased $1.1{\sim}3.2$ times according to the metal kind. In addition, the concentration of heavy metals in the brown rice also lowered by $27{\sim}75%$. Artificial Granular Zeolites (AGZ) was developed for the purification of wastewater. Canon exchange capacity was 126.8 $cmol^+{\cdot}kg^{-1}$. AGZ had Na-Pl peaks mainly with some minor $C_3S$ peaks in X-ray diffractogram. In addition, AGZs had various pore structure that may be adhere the suspended solid and offer microbiological niche to decompose organic pollutants. AGZ could remove ammonium, orthophosphate and heavy metals simultaneously. Mixing ratio of artificial zeolite in AGZs was related positively with removal efficiency of $NH_4\;^+$ and negatively with that of $PO_4\;^{3-}$. Root growth of rice seedling was inhibited severely in the mine wastewater because of strong acidity and high concentration of heavy metals. As AGZ(1 kg) stayed in the wastewater(100L) for 4days, water quality turned into safely for agricultural usage and rice seedlings grew normally.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.1
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• pp.42-49
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• 1983

In order to find out the possibility of predicting fertilizer K requirement from the K supplying capacity of soil, the relative K activity ratio, Kas/kai, the potential buffering capacity of $K^+$ ($PBC^k$ ; the liner regression coefficient) and its activity ratio ($AR^k_o$ ; $^{k+}$/${\sqrt{Ca^{+2}+Mg^{+2}}}$ in mol/l) at ${\delta}K$ = O, in the Q/I relationships of Beckett(1964), were determined for the soils before flooding and the samples taken at heading stage of transplanted rice in pot experiment. These parameters assumed as the K supplying capacity of soils were subjected for the investigation through correlation stady between themselves and other factors such as grain yield or the amounts of $K_2O$ uptake by rice plant at harvest. The results may be summarized as follows; 1. The potassium supplying power of the flooded soil was considered to be ruled by the amounts of exchangeable K before flooding, since there was little change in exchangeable K concentration from no-exchangeable K during the incubation periods of 67 days. 2. The $PBC^k$ values, in soils before flooding were 0.027, 0.014 and 0.009, where as the $AR^k_o{\times}10^{-3}$ values were 9.1, 7.6, and 15.4, respectively, in clay, loamy and sandy loam soils. 3. The $PBC^k$ values, determined in the soil samples taken at heading stage, varied little compared with the values of orignal soil, regardless of those different fertilizer treatments and textures, showing the possibility of using them as a factor for the improvement of soil to increase the efficiency of fertilizer K. 4. The significant yield responses to potassium fertilizer application were observed wherever the $AR^k_o$ values in soil at heading stage drop down to the original $AR^k_o$ values, regardless of any levels of fertilizer application. 5. The higher correlations between the gain yield or the amounts of $K_2O$ uptake and by the use of both soil factors of $PBC^k$ and $AR^k_o$ at heading stage were observed compared with the use of any single factor. 6. The Kas/Kai value in the soil, estimated prior to the experiment, had high possitive correlation with the $AR^k_o$ determined in the soil at heading stage and could be used as a soil factor for predicting potassium fertilizer requirement.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.59-65
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• 2004

Interactions of phosphorus and zinc in soils are important to determine the availability of the elements because those elements are closely related in the agricultural environment. The objective of this study was to investigate the interactions of P and Zn using desorption quantity (Q)-intensily(I) isotherms. Physically and chemically different soils, acidic Egan, acidic sandy Egeland, calcareous Glenham, and neutral Maddock, were used. The soils were enriched with different concentrations of P and Zn as $KH_2PO_4$ and $ZnSO_4$ solutions, respectively. Zinc enrichments affected availability of P in the Egan soil, which contained higher amounts of clay, organic matter, and exchangeable Fe than the other soils tested. After Zn enrichments, the pH drastically decreased in Egeland sandy soil, not changed in the calcarious Glenham soil, and slightly decreased in Egan and Maddock soil systems. The values of $Q_{max}$ and $I_0$ of phosphorus decreased with increasing Zn concentrations enriched in all soils, the changes of those values did not influence the P buffering power, |$BP_o$| values, in most soils. The influences of P treatment on Zn availability were varied. The values of Zn buffering capacity, $BC_{Zn}$, were lowest in the Egeland soil that had the lowest soil pH, amounts of clay minerals, organic matter, CEC, and exchangeable Fe, and were highest in the calcareous Glenham soil. The $BC_{Zn}$ values ranged from 202 to 4480. With P application, the changes of $BC_{Zn}$ values were more affected by the changes of soil solution Zn contents (I) than the changes of DTPA extractable Zn contents(Q). The change of Q and I values was found to be dependent upon soil properties, especially, soil pH.