Influence of hydrodynamic parameters in plate heat exchangers in ice slurry transport

Jiménez Pacheco Hugo Guillermo,Milon Guzmán Juan José,Miranda Ramos Lilia Mary,Delgado Sarmiento Pavel Kewin,Linares Flores Castro Antonio Erick,Leal Braga Sergio 대한설비공학회 2023 International Journal of Air-Conditioning and Refr Vol.31 No.1

Ice slurry is applied in different refrigeration and air conditioning systems, and among its main advantages is the ability to store latent heat and be pumpable as cold water. This fluid can be used for thermal storage instead of cold water or solid ice, since, at certain concentrations, it can be pumped through heat exchangers. For this technology to be widely used, the equipment must be designed considering the heat exchange characteristics. This study developed an experimental system to study the parameters that influence heat exchange, using ice slurry in a plate heat exchanger and water as a thermal load. Several situations with different flows and initial fractions of ice in ice slurry were analyzed. The input conditions of the thermal load were kept constant, the temperature, the pressure drop and the flow of the ice slurry in the heat exchanger were controlled, according to the Nusselt, Prandtl, and Reynolds coefficients. Results show that the global heat exchange coefficient increases with the increase of the initial ice fraction; the cooling capacity of the heat exchanger increases when ice slurry is used as a fluid. For flow rates greater than 0.16 kg/s and ice fractions above 11%, ice crystals are generated at the heat exchanger outlet, due to the ice slurry’s higher viscosity, at approximately 0.003 Pa at the outlet, since the pressure drop increases as the initial ice fraction increases. Results show ice slurry thermohydraulic behavior. Its use shows favorable characteristics in heat exchange. Ice slurry is applied in different refrigeration and air conditioning systems, and among its main advantages is the ability to store latent heat and be pumpable as cold water. This fluid can be used for thermal storage instead of cold water or solid ice, since, at certain concentrations, it can be pumped through heat exchangers. For this technology to be widely used, the equipment must be designed considering the heat exchange characteristics. This study developed an experimental system to study the parameters that influence heat exchange, using ice slurry in a plate heat exchanger and water as a thermal load. Several situations with different flows and initial fractions of ice in ice slurry were analyzed. The input conditions of the thermal load were kept constant, the temperature, the pressure drop and the flow of the ice slurry in the heat exchanger were controlled, according to the Nusselt , Prandtl , and Reynolds coefficients. Results show that the global heat exchange coefficient increases with the increase of the initial ice fraction; the cooling capacity of the heat exchanger increases when ice slurry is used as a fluid. For flow rates greater than 0.16 kg/s and ice fractions above 11%, ice crystals are generated at the heat exchanger outlet, due to the ice slurry’s higher viscosity, at approximately 0.003 Pa at the outlet, since the pressure drop increases as the initial ice fraction increases. Results show ice slurry thermohydraulic behavior. Its use shows favorable characteristics in heat exchange.

액상분뇨 이용 수준에 대한 현장적용 연구

류종원,헬무트야콥 한국축산환경학회 2002 축산시설환경학회지 Vol.8 No.1

장기간 액상분뇨 시용으로 토양에 질소가 과다하게 축적된 독일 남서부에 위치한 알고이 지방 2개 축산 농가 포장에서 환경과 자연을 보호하면서 사료작물을 재매하는 기술을 확립하기 위하여 1987년에서 1993년까지 7년간 관행 액비 시용구와 액상분뇨 감량 시용구, 무비구를 두어 액상분뇨 시용수준이 초지 생산성에 미치는 현장 적용실험을 실시한 결과를 요약하면 아래와 같다. 1. 7년간 액상분뇨를 사용하지 않는 무비구 토양은 pH와 인산, 가리 함량이 매우 낮아졌다. 액상분뇨 경감시용구 토양은 관행액비시용구보다 인산, 가리 함량이 약간 낮아졌다. 2. 초지의 식생 구성요소와 품질은 액비시용량 경감에 의하여 부정적으로 변화되지 않았다. 3 액비 경감시용구의 건물수량은 관행액비 시용구와 비교하여 지역에 따라 전혀 감소가 없거나 14% 감소되었다. 무비구의 건물수량은 지역에 따라 관행 액비시용구에 비하여 각각 14%,44% 감소되었다. 4. 장기간 액상분뇨 시용으로 토양이 비옥한 지역에서 액비 시용수준을 30∼40% 경감시키면 목초생산산성이나 식생에 전혀 지장을 주지 않고 목초의 품질면에서는 조단백질 함량을 낮고 조섬유 함량이 다소 높아 긍적적인 효과로 평가되기 때문에 이 지역의 관행액비 시용량은 감소되어야 할 것으로 결론 내려진다 The aim of the study is to describe the fate and transformation of nitrogen in grassland ecosystems. In the growing season from 1987 to 1993, 2 growing farmer in south Germany were studied the yield and nutrient balance of reduced input slurry application. The study includes 3 different slurry application levels. The levels are conventional slurry application, reduced slurry application, without slurry application. These levels are studied at 2 different experimental farms. The forage yield of zero slurry application plot has 14∼44% of the conventional slurry application, while the yield in the reduced slurry plot is only 0∼14% lower than that in the conventional slurry plot. The kalium and phosphorus contents of forage were tend to decrease with reduced slurry application N-uptake was increasing with the increase of slurry application level. The N-uptake of zero slurry plots was lower 40∼65% of the conventional plot, while in the reduced plot was only 6∼16% lower than in the conventional plot. The N-balance shows negative figures on all plots. The N-uptake in experiment site A was only a little bit more than the N-fertilizer plot, while in site experiment B the N-uptake is 2 to 3 times higher than the N-application amount of slurry.

Fabrication and Analysis of an Effective Composite Desiccant for the Rapid Dehydration of Shield Waste Slurry

Xuquan Huang,Xiuqing Xie,Zhuo Liu,Anyi Huang,Zaiqian Wang,Ruting Wang,Xiaorong Zhao 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.8

Massive shield waste slurry generated in shield tunnel construction is difficult to deal with because of its high water content (WC). Only when the WC of waste slurry is reduced to 40% − 60% it can be further disposed and reutilized. Three inorganic materials including attapulgite (AT), montmorillonite (MT) and water-washed kaolin (WK) were utilized to dehydrate the shield waste slurry and found that the WC of shield waste slurry dropped to 48.3%, 48.2% and 49.6% with 12.5% AT, 10% MT, and 12.5% WK as the desiccant, respectively. To enhance the dehydration efficiency, a composite desiccant was prepared with AT, MT and WK for the rapid dehydration of waste slurry. The optimized ratio of composite desiccant for AT: MT: WK was decided as 3.23%: 3.50%: 3.40% by response surface methodology based on Box-Behnken design, corresponding with the predicted WC as 44.9%. The WC of shield waste slurry can be decreased to 44.1% after the waste slurry has been dehydrated with the optimal composite desiccant after 6 days. The pH value of solidified shield waste slurry cured with the optimal composite desiccant was approximately 10.5, benefiting the further disposal and resource reutilization of shield waste slurry. The shield waste slurry was characterized by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. The results revealed that hydration products came into being during the hydration reaction when the shield waste slurry was cured with desiccant. The hydration products refabricated the microscopic lamellar structure of the waste slurry, squeezed the interlayer gap and drove the interlayer water away, leading to the depression of the WC of waste slurry.

돈분슬러리의 산성화처리에 따른 질소무기질화과정 및 암모니아 배출

박상현 ( Sang-hyun Park ),김태환 ( Tae-hwan Kim ) 한국축산학회(구 한국동물자원과학회) 2021 동물자원연구 Vol.32 No.2

This study was conducted to assess the effect of acidification of pig slurry on nitrogen (N) mineralization and its environmental impacts during pig slurry fermentation. Different inorganic and organic acids were used to acidify pig slurry. Four treatments including non-acidified pig slurry (control), pig slurry acidified with sulfuric acid, lactic acid, and citric acid were allocated with three replications. The total N content in the acidified pig slurry was higher than non-acidified pig slurry after fermentation. Acidification tended to increase total N content in pig slurry. Ammonium N (NH₄ ⁺-N) released from pig slurry was obviously increased at 7 days after incubation, representing 61.4%, 36.8%, and 37.4% increase in the acidified pig slurry with sulfuric acid, lactic acid, and citric acid, respectively. Nitrate N (NO₃ ^--N) in the acidified pig slurry with sulfuric acid was the highest throughout the experiment period, but non-significant effect of organic acid. A large portion of ammonia (NH₃) emission occurred within 10 days, corresponding to more than 55% of total NH₃ emission. Total cumulative NH₃ emission during the experimental period was lower 91% (2.9 mg N kg^-1), 78% (7.3 mg N kg^-1), and 81% (6.2 mg N kg^-1) in the acidified pig slurry with sulfuric acid, lactic acid, and citric acid, respectively, than non-acidified pig slurry (32.7 mg N kg^-1). These results suggest that acidification of pig slurry (particularly with sulfuric acid) can be faced as a good strategy to reduce NH3 emission without depressing the mineralization process.

산화막 CMP 공정에서 슬러리 온도 변화에 따른 연마 특성

고필주,박성우,김남훈,서용진,이우선,Ko, Pil-Ju,Park, Sung-Woo,Kim, Nam-Hoon,Seo, Yong-Jin,Lee, Woo-Sun 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.3

To investigate the effects of slurry temperature on the chemical mechanical polishing(CMP) performance of oxide film with silica and ceria slurries, we have studied slurry properties as a function of different slurry temperature. Also, the effects of each input parameter of slurry on the oxide CMP characteristics were investigated. The pH showed a slight tendency of decrease, the conductivity in slurries showed an increased tendency, the mean particle size in slurry decreased, and the zeta potential of slurry decreased with temperature. The removal rates significantly increased and maintained at the specific levels over 4$0^{\circ}C$. The better surface morphology of oxide films could be obtained at 40 $^{\circ}C$ of silica slurry and at 90 $^{\circ}C$ of ceria slurry. It is found that the CMP performance of oxide film could be significantly improved or controlled by change of slurry temperature.

해수가 슬러리 쉴드 TBM 공법 적용성에 미치는 영향

유영무,김해만,김도형,이인모 사단법인 한국터널지하공간학회 2019 한국터널지하공간학회논문집 Vol.21 No.2

Formation of filter cake with little slurry penetration into the tunnel face ground is an essential factor to successfully apply the slurry shield tunnel boring machine (TBM) for tunnelling work. However, when the bentonite slurry is in contact with seawater, it is not easy to guarantee the filter cake formation due to decrease of the swelling volume and viscosity of the slurry. In this study, in order to evaluate the effect of the seawater on the applicability of the slurry shield TBM method, the slurry injection tests were carried out with the variation of seawater percentage contained in the slurry samples as well as the variation of soil types. And then, the effect of these two factors on the slurry clogging phenomena was theoretically and experimentally figure out. As a result, it was found that the value of the slurry clogging criteria (SCC) indicating the applicability of the slurry shield TBM significantly decreases up to 67% as the percentage of seawater increases from 0% up to 20%. In addition, it was found to be necessary to take into account both the characteristics of slurry and soil types together when judging the applicability of the slurry shield TBM method by assessing the slurry penetration characteristics that will occur during tunnelling work. 슬러리 쉴드 TBM (Slurry shield TBM) 공법에서 벤토나이트 슬러리의 침투와 필터 케이크의 형성 여부는 공법의 적용성에 영향을 미치는 중요한 요소이다. 그러나 벤토나이트 슬러리는 해수와 접촉하였을 때 팽윤성과 점도가 저하되어 공법에 대한 적용성을 확보하기 어렵다. 본 연구에서는 해수의 영향에 따른 슬러리 쉴드 TBM 공법의 적용성 변화를 평가하기 위해 슬러리의 해수 비율을 다르게 하여 주입 실험을수행하였고 해수가 슬러리의 폐색 현상에 미치는 영향을 확인하였다. 그 결과, 해수의 비율이 0%에서 20%까지 증가할수록 폐색 효과에 의한 슬러리 쉴드 TBM 공법의 적용성을 나타내는 slurry clogging criteria (SCC)가 최대 67%까지도감소하는 것을 확인하였다. 또한 슬러리의 물리적 성질이 동일함에도 지반 조건에 따라 SCC값이 공법 적용에 문제가 없는 수준에서 공법 적용을 위해 슬러리에 추가적인 처리를 요하는 수준으로 변화하는 것을 통해 슬러리 쉴드 TBM의 적용성을 평가할 때 슬러리의 특성뿐만 아니라 지반 조건에 대한 고려도 필요함을 입증하였다.

Surface Activation by Electrolytically Ionized Slurry during Cu CMP

Lee, Dasol,Lee, Hyunseop,Jeong, Seonho,Yuh, Minjong,Jeong, Haedo The Electrochemical Society 2019 ECS journal of solid state science and technology Vol.8 No.5

<P>In semiconductor chip fabrication, flatness of the layer is vital, and is achieved by chemical mechanical planarization (CMP). Slurry determines mechanisms for removal, and therefore accounts for the most expense in CMP. However, conventional slurry supply systems lead to wastage of the slurry not used in polishing. Therefore, this study proposes a new slurry supply method using ionization of slurry by electrolysis. Applying an electric force to the slurry may significantly reduce slurry consumption in the CMP process. First, stainless steel was selected as a suitable electrode for the system through a simple experiment. With this system, the material removal rate was evaluated according to the applied voltage and compared to that in the conventional method under different slurry flow rates. The removal mechanism of the ionized slurry was investigated by UV-visible spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The band intensities of the intramolecular bonding structures and amounts of oxygen and Cu oxide on the surface were different depending on the electrolysis in the slurry. Accordingly, the effect of the ion-rich slurry was verified. This method is promising for efficient slurry supply systems in CMP applications as well as other manufacturing processes.</P>

양돈 슬러리의 암모니아 발생 특성에 관한 연구

이성현,윤남규,김경원,이인복,김태일,장진택,Lee S.H.,Yun N.K.,Lee K.W.,Lee I.B.,Kim T.I.,Chang J.T. 한국축산환경학회 2006 축산시설환경학회지 Vol.12 No.1

본 연구에서는 육성 비육돈 슬러리를 이용하여 슬러리의 환경조건에 따라 슬러리로 부터의 암모니아 발생 특성을 분석코자 하였다. 슬러리의 온도와 pH를 조절하여 슬러리로부터 발생하는 암모니아 농도를 측정 분석한 결과 슬러리의 온도가 높을수록 슬러리로 부터 발생하는 암모니아 농도는 급격히 증가하는 것으로 나타났고, 슬러리의 pH를 5, 6, 7, 8의 4수준으로 조절하여 각각의 온도에 따라 발생하는 암모니아 농도를 측정한 결과 pH 5, 6에서는 암모니아 가스가 검출되지 않았으나 pH 7, 8에서는 많은 양의 암모니아 가스가 검출되었고 양돈 슬러리의 pH가 높을수록 발생하는 암모니아 가스가 많이 발생하는 것으로 분석되었다. 본 연구결과 슬러리의 온도를 낮추어 주거나 슬러리의 pH를 낮춤으로써 슬러리로부터 발생하는 악취가스를 크게 줄일 수 있을 것으로 판단되었다. Ammonia emission from swine production process originates from three major sources: manure storage facility, swine housing, and land application of manure. Most of the ammonia gas that are emitted from swine production operations is the by-product of aerobic or anaerobic decomposition of swine waste by microorganism. Knowing the ammonia emission rate is necessary to understand how management practices or alternative manure handling process could reduce impacts of this emission on the environment and neighbors. Ammonia gas emission from pig slurry is very difficult to predict because it is affected by many factors including wind speed of slurry surface, temperature or pH of the swine slurry, sort breed differences and classes, and diets. This study was carried out to effects of pH and temperature on ammonia gas emission from growing-finishing pig slurry. Treated far slurry in this study were pH and temperature. Results showed that pH of slurry variable changes 5, 6, 7, 8 upon an addition of NaOH and $HNO_3$, respectively. The temperature of the slurry which was contained in a water bath maintained at increasing levels ranging from 10 to $35^{\circ}C$. Ammonia emission rate of influenced pH and temperature such that the increase in pH or temperature resulted to an increase in ammonia emission. The ammonia gas was not detected at pH 5 and 6. Moreover, at a slurry of pH 8, the ammonia ranged from 28 to 60ppm and 8-29 ppm at slurry pH of 7 while temperature was 13 to $33^{\circ}C$. When slurry pH was>6, the ammonia emission was significantly increased according to rise in temperature in contrast to acid treatment of the pH. There was also a significantly increase in ammonia emission relative to slurry pH of 7 to 8. The above findings showed that to effectively reduce ammonia emission from slurry of growing-finishing pigs, the pH and temperature should be maintained a low levels.

Effect of Non-Spherical Colloidal Silica Particles on Removal Rate in Oxide CMP

이호준,김문성,정해도 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

Oxide CMP generally has used colloidal silica slurry and fumed silica slurry. To compensate the lower removal rate (RR) of colloidal silica slurry compared to the one of fumed silica slurry, the multi-step feeding method was used to produce a non-spherical silica particle, for which the existing spherical colloidal silica particle was combined with two to three particles. To improve the performances, the prepared non-spherical colloidal silica particles were assessed by both single and mixed abrasive slurry. The slurry has two different sizes, 30 nm and 70 nm, of spherical colloidal silica particles and 70nm of non-spherical colloidal silica particles. Through the experiments, it was found out that non-spherical colloidal silica slurry had the higher RR than spherical colloidal silica slurry, and its RR was similar to the one of fumed silica slurry. For mixed abrasive slurry, the combinations of spherical and spherical or spherical and non-spherical showed higher RR, which were 152.8% higher than single abrasive slurry and 19.3% higher than fumed silica slurry, and better surface roughness than the fumed silica slurry. Therefore, non-spherical colloidal silica particles are found to be efficient to gain a higher RR and a better surface roughness than the ones of fumed silica particles.

Experimental Study on Interaction between Slurry and Soil on Excavation Face of Shield in Sand Stratum

Jiahua Mao,Dajun Yuan,Binghui Wang,Shengnan Liu,Liping Chen 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1

In sandy soil, the timely and effective formation of a filter cake is crucial for maintaining the stability of the excavated face during slurry shield tunnelling. Obtaining real-time information on slurry infiltration and particle migration is challenging, which greatly impacts the formation of the filter cake. Real-time monitoring of slurry infiltration and particle deposition is achieved through the use of electrical resistivity and pore water pressure measurements of the soil. It has been discovered that the primary pathway for slurry infiltration is inevitable in sandy soil, and it is crucial to take note of the persistent slurry leakage resulting from this situation in the shield excavation face. The distribution of slurry particle deposition is highly non-uniform in the penetration direction, with the maximum particle deposition occurring at the slurry-soil interface. However, this deposition is susceptible to disturbance from shield cutting tools, which can compromise the safety of the excavation face. Even if the particle size of the slurry is smaller than the pore size of the sand stratum, the slurry with higher viscosity can still form an internal filter cake. Furthermore, the research indicates that slurry infiltration can induce regular changes in soil electrical resistivity.