최근 국내에서 세계 최초로 개발한 SWRO-PRO 복합해수담수화 시스템은 압력지연삼투(PRO) 기술을 활용하여 역삼투(SWRO) 해수담수화 플랜트에서 발생하는 고염도 농축수의 삼투에너지를 회수하는 기술이다. 고염도 농축수와 저염도 하수처리수를 각각 PRO 시스템의 유도용액과 유입수로 사용하며, 두 용액의 농도차에 의해 발생되는 삼투에너지를 압력교환장치(isobaric pressure exchanger)를 통해 회수하여 SWRO 고압펌프에서 필요한 에너지를 줄이거나, 터빈 형태의 에너지 회수장치(Pelton turbine)를 통해 전력을 생산하는 기술이다. PRO 시스템을 통해 회수된 에너지는 해수담수화 운영비를 절감하는데 기여하고, 고농도 농축수의 희석 방류로 해양생태계 영향을 최소화 시킬 수 있다.

Recently, interest in the development of alternative water resources has been increasing rapidly due to environmental pollution and depletion of water resources. In particular, seawater desalination has been attracting the most attention as alternative water resources. As seawater desalination consumes a large amount of energy due to high operating pressure, many researches have been conducted to improve energy efficiency such as energy recovery device (ERD). Consequently, this study aims to compare the energy efficiency of RO process according to ERD of isobaric type which is applied in scientific control pilot plant process of each 100 m3/day scale based on actual RO product water. As a result, it was confirmed that efficiency, mixing rate, and permeate conductivity were different depending on the size of the apparatus even though the same principle of the ERD was applied. It is believed that this is caused by the difference in cross-sectional area of the contacted portion for pressure transfer inside the ERD. Therefore, further study is needed to confirm the optimum conditions what is applicable to the actual process considering the correlation with other factors as well as the factors obtained from the previous experiments.

본 연구에서는 이미 보고된 잉여 태양에너지 관련 연구결과와 현재 현장에 설치되어 있는 냉난방용 FCU 현황을 개략적으로 검토한 후, 잉여 태양에너지 회수에 필요한 FCU의 소요대수 결정 방법을 개략적으로 제시하여 앞으로 이 분야의 연구자 및 기술자들에게 기조자료를 제시할 목적으로 연구를 수행하였다. 실험기간 동안 최대, 평균 및 최저 외기온은 각각 28.2oC, 4.4oC 및 -11.5oC정도였다. 온실 밖의 수평면 일사량은 0.8~20.5MJ·m-2로 정도의 범위였으며, 평균 및 총 일사량은 10.8MJ·m-2 및 1,187.5MJ·m-2으로 나타났다. 그리고 주간동안 온실 내의 평균기온과 상대습도는 각각 18.8~45.5 및 53.5~77.5%정도였다. 실험기간 동안 온실로부터 회수한 총 잉여 태양에너지는 6,613.4MJ정도로서 총 난방에너지인 98,600.2MJ 약 6.7%정도를 보충할 수 있을 것으로 나타났다. 또한 사양이 유사한 FCU를 사용하지만, 난방을 위하여 설치되는 FCU의 대수는 제각각 다른 것을 알 수 있었고, 좀 더 효율적이고 경제적인 관점에서 설치높이, 방향 및 설치 간격, 적정 대수에 대한 연구가 이루어져야 할 것으로 판단된다. 잉여 태양에너지 회수용 FCU의 적정 소요대수는 FCU를 통과하는 공기의 질량 및 순환유량을 기준으로 각각 8.4~10.9대 및 6.1~8.0대 정도이었다. 여기에 계산방법이나 FCU의 효율 및 사용 환경 등 위험률을 고려하면, 결국 9대 전후(약 24m3당 1대 정도)를 설치하면 될 것으로 판단되었다.

역삼투(RO) 해수담수화 공정에 필요한 많은 에너지를 절감하기 위해 최근에 다양한 연구개발이 추진 중이다. 그 중에서 농도차에 의해 발생하는 삼투현상을 이용한 정삼투(FO)와 압력지연삼투(PRO) 기술을 접목한 하이브리드 해수담수화 공정들이 대표적이다. 특히, PRO 기술은 해수담수화 플랜트에서 배출되는 농축수와 하수처리수를 PRO 시스템의 유도용액과 원수로 각각 활용하여 두 용액의 염도차에 의해 발생되는 에너지를 회수함으로써, 기존 역삼투 해수담수화 공정 대비 25% 이상의 에너지 절감이 가능하며, 해수담수화 플랜트의 고농도 농축수를 희석 방류함으로써 해양생태계 파괴 방지 및 농축수 처리비용 절감 등의 효과를 기대할 수 있다.

Recently, Korea’s municipal wastewater treatment plants generated amount of wastewater sludge per day. However, ocean dumping of sewage sludge has been prohibited since 2012 by the London dumping convention and protocol and thus removal or treatment of wastewater sludge from field sites is an important issue on the ground site. The hydrothermal carbonization is one of attractive thermo-chemical method to upgrade sewage sludge to produce solid fuel with benefit method from the use of no chemical catalytic. Hydrothermal carbonization improved that the upgrading fuel properties and increased materials and energy recovery ,which is conducted at temperatures ranging from 200 to 350°C with a reaction time of 30 min. Hydrothermal carbonization increased the heating value though the increase of the carbon and fixed carbon content of solid fuel due to dehydration and decarboxylation reaction. Therefore, after the hydrothermal carbonization, the H/C and O/C ratios decreased because of the chemical conversion. Energy retention efficiency suggest that the optimum temperature of hydrothermal carbonization to produce more energy-rich solid fuel is approximately 200°C.

This study is nutrient heating effect to apply the surplus heat recovery in greenhouse using fan coil unit. Especially, this study was carried out to utilize a surplus heat in greenhouse. This fan coil unit system was composed of a water tank, a fan coil unit, a circulating pump and a water-water heat exchanger. As the result, Temperature difference duing to fan coil unit in greenhouse showed that air temperature at experimental greenhouse on fan , comparison greenhouse were 28.3℃, 33.9℃, respectively. heat ratio showed that exchanged energy quantity in fan coil unit was 19,900∼28,880kcal/h, respectively. It was found that difference of nutrient temperature due to surplus heat recovery, water tank temperature were 19.2∼21.5℃ and 16.2∼18.3℃, The temperature variation of nutrient temperature was about 3℃ and higher . Economic analysis of fan coil unit system was increased gross income cost by 804,787 won.

This technology is to highly produce heat by microorganism during fermentation of mushroom sludge as a byproduct at farm field which would be established more competitive in mushroom growers and distinguished technology with ordinary mushroom growers. Furthermore this technology could be reduced energy as well as high efficiency in resource uses. There was highly reduction in energy consumption using by heat during fermentation of mushroom sludge which was produced by different media material with vegetable for mushroom cultivation. After 4 days the inner temperature during fermentation of mushroom media was a little changes of 61～50℃ and inner temperature of fermentation chamber was 55～45℃, inlet temperature of cooling water was 17℃, outlet temperature was 44～35℃, and ambient temperature was 28℃ at daytime and 14℃ at night time which was relatively constant. A heat exchange from fermentation chamber was 1090～648㎉/10min and the maximum heat exchange was 11550～1064㎉/10min which was caused to reduce fermentation heat with time The efficiency of heat exchange was distributed with 81～61% with time.

In this study, we evaluated the energy production from plant-microbial fuel cells using representative indoor plants, such as Scindapsus aureus and Clatha minor. The maximum power density of microbial fuel cell (MFC) using S. aureus (3.36 mW/m2) was about 2 times higher than that of the MFC using C. minor (1.43 mW/m2). It was confirmed that energy recovery is possible using plant-MFCs without fuel. However, further research is needed to improve the performance of plant-MFCs. Nevertheless, plant-MFCs have proved their potential as a novel energy source to overcome the limitations of the conventional renewable energy sources such as wind power and solar cells, and could be employed to a power source for the sensor in charge of the fourth industrial revolution.

This study measured the energy recovery rate of each municipal waste incineration facility according to the revised energy recovery rate estimation method, which targeted four municipal waste incineration facilities (Unit No. 7). The results calculated by the measuring instruments were used for each factor to estimate the recovery rate, and the available potential of available energy was examined by analyzing the energy production and valid consumption. As a result of the low heating value, 2,540 kcal/kg was calculated on average when the LHVw formula was applied, which is approximately 116 kcal/kg higher than the average design standard of 2,424 kcal/kg. The energy recovery rate was calculated as 96.9% on average based on production and 67.5% based on effective consumption, and the analysis shows that approximately 29.4% energy can be used.

This study was carried out to examine the improvement plan by analyzing the characteristics of imported wastes, operation rate, and benefits of energy recovery for incineration facilities with a treatment capacity greater than 50 ton/ day. The incineration facility capacity increased by 3,280 tons over 15 years, and the actual incineration rate increased to 2,783 ton/day. The operation rate dropped to 76% in 2010 and then rose again to 81% in 2016. The actual calorific value compared to the design calorific value increased by 33.8% from 94.6% in 2002 to 128.4% in 2016. The recovery efficiency decreased by 29% over 16 years from 110.7% to 81.7% in 2002. Recovery and sales of thermal energy from the incinerator (capacity 200 ton/day) dominated the operation cost, and operating income was generated by energy sales (such as power generation and steam). The treatment capacity increased by 11% to 18% after the recalculation of the incineration capacity and has remained consistently above 90% in most facilities to date. In order to solve the problem of high calorific value waste, wastewater, leachate, and clean water should be mixed and incinerated, and heat recovery should be performed through a water-cooled grate and water cooling wall installation. Twenty-five of the 38 incineration facilities (about 70%) are due for a major repair. After the main repair of the facility, the operation rate is expected to increase and the operating cost is expected to decline due to energy recovery. Inspection and repair should be carried out in a timely manner to increase incineration and heat energy recovery efficiencies.

Domestic automotive shredder residue (ASR) recycling facilities must comply with 60% of the energy recovery criteria calculated by the waste control act, based on resource circulation of electrical and electronic equipment and vehicles. The method of calculating energy recovery criteria was newly enacted on November 6, 2017, and it has been judged that it is necessary to consider applicability. In this study, the energy recovery efficiency of 7 units was calculated by past and present calculation methods. Furthermore, this study attempts to find applicability and a method of increasing the energy recovery efficiency by taking advantage of available potentials. An analysis of the calculation results showed that the average values calculated by past methods, present methods, and the method that includes available potentials are 76.35%, 70.68%, and 78.24%, respectively. Therefore, the new calculation method for energy recovery efficiency is also applicable to domestic automotive shredder residue recycling facilities.

폐기물은 발생원을 기준으로 생활폐기물, 사업장폐기물 및 건설폐기물로 구분된다. 폐기물 처리는 재활용을 우선적으로 정책이 이루어지고 있다. 그러나 폐기물을 재활용하기 위해서는 기술적인 한계성과 경제성 등이 해결되어야 하며 이러한 이슈가 극복되지 않으면 재활용에는 한계가 따른다. 국내에서 도입된 네가티브 재활용 제도가 다양한 기술을 재활용로서 적용될 수 있도록 하였으며, 그 중 폐기물 에너지화 기술로써만 인식되어온 폐기물 가스화 기술은 에너지회수 기술 뿐 만 아니라 원료를 대체할 수 있는 재활용 기술로도 적용될 수 있게 되었다. 폐기물의 재활용은 물질재활용 기술로서 3R기술 위주로 재활용되어 왔으나 화학전환 기술에 의한 재활용을 위해서는 가스화 기술이 많은 기여를 할 것으로 기대된다. 또한 폐기물의 에너지 회수기술은 소각에 의한 에너지회수 또는 고형연료를 생산하여 연소보일러에 의한 에너지회수 방법이 주로 이용되어 왔으며 이러한 기술은 열에너지를 회수하는 기술에 국한되어 있다. 그러나 폐기물 가스화 기술은 열에너지와 화학에너지의 생산이 가능하므로 다양한 에너지로의 회수 기술과 고효율 에너지 이용기술의 적용이 가능한 기술이다. 따라서 본 연구에서는 폐기물 가스화를 통한 에너지회수 기술과 화학전환 기술로서 원료대체를 통한 재활용 기술로서의 특성을 고찰하였다. 폐기물 가스화 기술은 가연성물질이 함유된 폐기물의 대부분을 대상으로 적용이 가능하지만 합성가스를 이용하는 기술에 따라서 합성가스의 생산품질을 만족하기 위해서는 폐기물의 적정 발열량이 확보되어야 된다. 폐기물의 종류에 따라 기준은 달리 적용되겠지만 저위발열량 기준으로 3,200 kcal/kg이상인 경우 안정적인 합성가스를 생산할 수 있다고 판단되며, 폐기물종류 및 이용기술에 따라서는 3,000 kcal/kg이상인 경우 합성가스 생산품질을 유지할 수 있다. 폐기물 가스화를 통해 생산된 합성가스를 에너지회수 기술로서는 스팀터빈, 가스터빈, 가스엔진, 연료전지 등의 기술을 적용할 수 있고, LNG, 경우, 석탄, LPG 등 화석연료를 대체하는 가스연료로 적용할 수도 있다. 또한 합성가스의 주요성분인 일산화탄소와 수소는 고순도 수소 및 고순도 일산화탄소 자체로도 원료대체가 가능하며, 화학촉매 또는 미생물촉매 전환 공정을 통해 다양한 화학원료로 대체하는 재활용기술로서의 적용이 가능한 특성을 가지고 있다.

In the past, the role of incineration facilities was mainly to reduce waste and stabilize disposed material. However, as a key aspect of waste management policy, the concept of “waste Minimization and sustainable resource circulation society” has become an issue, and the effective use of waste has been emphasized. As a result, to promote the recycling of wastes from January 1, 2018, the Framework Act on Resource Circulation has been implemented. In this study, estimation factors that can affect the increase of energy recovery are selected by reviewing the estimation method of industrial waste incineration facilities having a separate boiler; moreover, the effect of calculation factors on energy recovery was quantitatively evaluated. According to this study, when the heat loss, condensate temperature, and power consumption decrease by 10%, the energy recovery of the target facilities increase by 0.4% (0.22 ~ 0.63%), 1.09% (0.57 ~ 1.32%), and 1.16% (0.52 ~ 2.13%) on an average.