Removal Of Free Water Research Articles

Additives Depletion by Water Contamination and Its Influences on Engine Oil Performance

Water enters engine oil in different ways and moves in the lubrication system causing an increase in wear, oil degradation and additives depletion. It has been proposed that water in the lubricants can transfer from dissolved to free phase leading to additives depletion in the oil. Different additives in the lubricants can easily latch to water molecules forming reverse micelles. The separation of reverse micelles from the oil causes additives depletion. This experimental and analytical study aims to investigate how the separation of free water above the saturation level can diminish the efficiency of additives in engine oils. The effect of varied levels of water on oil performance and its additives was investigated in this study. A new saturation method was used to determine the water saturation level in engine oil at different temperatures. The results reveal a decrease in additive concentration with increased separation of free water from the oil. Free water separation from engine oil is expected to reclaim the tribological performance, however, the results demonstrate that tribological performance after the separation of free water from the oil has been affected. The study showed not only does the removal of free water diminish the efficiency of additives due to additives depletion (≈ 10 wt%), but also the remaining dissolved water which is ≈ 2600 ppm can also affect wear and tribofilm chemistry. The results prove that two main mechanisms influence oil performance expressed as additives depletion by free water and remaining dissolved water.

Efficient synthesis of DHA/EPA-rich phosphatidylcholine using immobilized phospholipase A1 on a novel microflow support

A new epoxy-based polymerizing/compositing synchronic process was carried out in 3D structure of a melamine sponge. The cured polymer formed a porous and wave-shaped coating on the surface of skeleton in a uniform way. The obtained composite sponge was used as a microflow support for the immobilization of phospholipase A1 (PLA1, from Thermomyces lanuginosus/Fusarium oxysporum) by co-adsorption/cross-linking with polyethylenimine (PEI). The loading amount and the specific activity of immobilized PLA1 under the optimal immobilization conditions were 45.7 mg/gsupport and 9.1 U/mgprotein. The PLA1-immobilized microflow supports were placed in a columnar reactor, in which transesterification was operated in continuous circulation way. The reaction produced DHA/EPA-incorporated phosphatidylcholine, the hydrolysis side reaction could be inhibited by removal of free water in the reaction medium. Under optimized conditions the incorporation percentage of DHA/EPA and PC yield of 54.3% and 82.4% within 18 h at 55 ℃, respectively. After 10 cycles, the immobilized PLA1 retained 71.2% of the original activity. The use of microflow support has an advantage on easier scaling up the reactor size towards much larger productivity and higher efficiency.

Use of low‐field nuclear magnetic resonance for moisture variation analysis of fresh in‐shell peanut during different drying methods

AbstractIn exploring the law of heat transfer and water diffusion of peanut, low‐field nuclear magnetic resonance (LF‐NMR) was used to analyze moisture migration in peanuts subjected to hot air drying (HAD), infrared drying (IRD), and sequential hot air‐infrared drying (HAD‐IRD) at 40, 50, 60, and 70°C. In HAD and IRD, free water was removed first, and some of free water was converted into loosely bound water. In HAD‐IRD, free water and loosely bound water were primarily removed. Regression models were used to predict changes of free water in peanuts. Based on MRI, the binding force on water decreases with the increase of temperature, and water migration from the inside to the outside is accelerated. HAD‐IRD can promote the removal of free water and the conversion of bound water into more easily removable water. This study revealed that HAD‐IRD can effectively reduce the drying time compared with HAD and IRD. Moreover, LF‐NMR can be an effective tool for detecting moisture changes in peanuts. The research results provide guidance for the selection of peanut processing technique.Practical applicationsDrying is an important food processing and preservation method based on the principle of reducing the moisture content of materials. Our study shows that HAD‐IRD is a superior, feasible drying method, as compared with other published works. This drying method removes a large amount of free water by hot air in the early stage and removes the remaining water by radiant heating in the later stage, which achieves rapid dehydration and greatly reduces the drying time. By identifying the moisture migration mechanism of the three drying methods, this study improves the drying theory and provides a theoretical basis for drying in the peanut processing industry.

Centrifugation forced ice-concentrate separation to enhance suspension freezing desalination performance

Suspension freeze desalination is a promising route for treatment of high salinity wastewater, but the poor ice-concentrate separation often generates decrease of desalination efficiency. In this work, it is demonstrated that centrifugation forced dewatering can assist in ice purification and enhance suspension freeze desalination performance. The positive correlation and good linear fitting relationship between ice purity and dewatering rate were identified at various centrifugation speeds, centrifugation time, and ice layer thickness. Changes of ice shape were recorded by low-temperature optical microscope observation system. The free water removal and ice floc destruction induced by centrifugal field have an important contribution to ice purification. Increasing centrifugation speed from 100 r/min to 500 r/min, the corresponding relative centrifugal force increased 27-fold, creating sharp increases in ice purity (rate constant k = 0.1605) and dewatering rate (rate constant D = 0.0563). Due to the strong binding characteristics and small portion of bound water, ice desalination efficiency per unit centrifugal force dropped when centrifugation speed increased from 1000 r/min to 3000 r/min. Besides, the multi-step dewatering and purification mechanism involved in ice centrifugation was depicted. The suspension freeze technology hybrid with centrifugation not only enhances desalination efficiency but also is beneficial to obtain high-purity ice.

Numerical Investigation on Flow-Field Characteristics towards Removal of Free-Water by A Separator with Coalescing Plates

The produced water-containing polymer brings new challenges to oil-water separation in oilfield production, yet separators with coalescing plates to remove free water have been playing an active role. In this paper, the flow-field characteristics of polymer-laden produced water in a separator with coalescing plates are analyzed using computerized mathematical methods to investigate the effects with a water content of 55%, 70%, and 85%, flow rate of 3500 m3/d, 4800 m3/d, and 6000 m3/d, and duration time of 20 min, 40 min, and 60 min on flow-field properties and separating efficiency are studied. The results show that the separating efficiency is positively correlated with water content and duration time, and duration time has the greatest improvement to the separating efficiency, but the enhancement of flow rate may reduce the separating efficiency. It is also observed that the separation efficiency of free-water reached 70.9% and the water content at the oil outlet of the separator reached 20.4% at a duration time of 60 min, when the contained polymer concentration and water content in the oil-water mixture are 500 mg/L and 70%, respectively.

Preparation of building ceramic bricks using waste residue obtained by mutual treatment of electrolytic manganese residue and red mud

The waste residue (ER) obtained by the mutual treatment of electrolytic manganese residue and red mud. ER is a kind of silicon and aluminum waste residue with low pollution. In order to alleviate the shortage of silicon-aluminum raw materials in ceramic bricks industry. In this paper, ER is used as a part of silicon-aluminum raw material to prepare building ceramic bricks. The results show that the impurity ions (Fe3+, Na+, K+, etc.) in ER can promote the formation of liquid phase during the calcination process. This makes the ceramic bricks can be successfully fired at 1150 °C. The mineral composition of ceramic bricks prepared by ER is anorthite, quartz, corundum, mullite and glass phase, and the corresponding contents are 40.31 wt%, 2.48 wt%, 6.81 wt%, 2.58 wt% and 35.07 wt%, respectively. The layer stacking of plate anorthite is closely combined with the corundum to form a microscopic block. The rod-like mullite is interspersed in the microscopic block to form a skeleton structure. This microstructure makes the mechanical properties of the ceramic bricks superior, and the compressive strength is 138.2 MPa. The sintering process of ceramic bricks prepared by ER can be divided into four stages. Stage 1 (25 °C–200 °C) mainly involved the removal of free water and crystal water and the decomposition of part of AlO(OH) into γ-Al2O3, the corresponding kinetic mechanism is phase boundary chemical second-order reaction mechanism. Stage 2 (200 °C–400 °C) mainly involved the residual AlO(OH) decomposed into γ-Al2O3, the corresponding kinetic mechanism is phase boundary–controlled reaction and one-dimensional movement mechanism. Stage 3 (400 °C–900 °C) mainly involved the γ-Al2O3 transformed into α-Al2O3, CaCO3 and CaSO4 decompose into CaO, and CaO reacts with SiO2 and α-Al2O3 to form (Ca,Na)(Al,Si)4O8 and CaAl2Si2O8, the corresponding kinetic mechanism is random nucleation and growth mechanism. Stage 4 (900 °C–1200 °C) mainly involved the melting of (Ca,Na)(Al,Si)4O8, and the continuous formation of CaAl2Si2O8, Ca(Al, Fe)12O19 and mullite, the corresponding kinetic mechanism is Mampel power law exponential form nucleation reaction mechanism.

A technical note on the effect of log length on the drying of Eucalyptus urophylla

ABSTRACT This study aimed to evaluate the drying rate of Eucalyptus urophylla hybrid logs of different lengths used for carbonisation. Six seven-year-old trees of two clones (VM4 and MN463) were harvested from experimental plots located in the region of Paraopeba, Minas Gerais, Brazil. Specimens were cut into four different lengths so that the ratios between cross-sectional area and curved-surface area were 1:1, 1:2, 1:5 and 1:10. Samples were then air-dried in an open shed for 170 days. Drying rates were calculated for different periods during air-drying. The fastest drying rates were observed during the first 28 days during the removal of free water. In general, the free-water drying rate was 5.7 times higher than that for bound water and 2.5 times higher than total drying rate. At the end of drying, the shortest drying rate occurred in shorter samples, being 3.2 times faster than the longest logs, regardless of the genetic material analysed. These findings are important for charcoal-producing industries, potentially helping that sector improve drying efficiency and produce higher-quality charcoal.

Silane functionalization on zeolite 13X surface for direct steam generation in a solid sorption heat pump

High-temperature steam has been directly generated from hot water based on a solid sorption heat pump system by employing silane functionalized zeolite 13X (XS). The adsorbent is prepared by a liquid phase grafting method to modify functional groups on the zeolite surface with a silane coupling agent. The static water contact angle (WCA) and surface functional groups are analyzed by optical contact angle measuring instruments and Fourier transform infrared spectroscopy (FTIR), respectively. Analytical results confirm the successful preparation of surface hydrophobic zeolite. The water adsorption capacity of XS is slightly less than that of 13X, while the overall adsorption heat remains almost constant. Dry air at 130 °C is utilized for the regeneration of the wet zeolite in cyclic experiments. Steam at 207 °C is generated from input hot water at 72 °C in a packed bed filled with XS-25 (zeolite 13X functionalized by a saline solution concentration of 25%). The thermal response during the steam generation process is accelerated by utilizing XS. The mass of steam product does not change during the generation with XS, whereas cyclic time is shortened. Moreover, XS facilitates the regeneration process by decreasing the heat demand for the removal of free water. System evaluation results show that a higher Sp (steam productivity) is obtained for XS than that for zeolite 13X. COPh (coefficient of performance for heating) and SHP (specific heating power) are elevated by 23.6% and 5.7% for XS compared with those for zeolite 13X, respectively.

Numerical simulation of heat and mass transfer during sublimation drying of porcine aorta

Freeze-drying is an effective method for aortal preservation. However, there are few studies on heat and mass transfer of aortal freeze-drying. In this study, the contactless weighing device was used to monitor freeze-drying process. The radiation view factor of the aortal segment was estimated, and the quasi-steady state model was used to analyze heat and mass transfer, there was a certain amount of heat flux in the frozen layer, which provided sublimation heat for internal sublimation interface. By theoretical calculation, the vapor diffusion coefficient was determined. The unsteady state model was used for numerical simulation. The simulated result of free water removal ratio was consistent with experiment result. Both heat flux density and mass flux density decreased non-linearly in the early stage, but approximately linearly in the late stage. The velocity of inner and outer sublimation interfaces was almost the same. The nodes temperature gradually increased and finally approached the heating temperature, and the temperature gradient of both dried and frozen layers decreased gradually with drying time. The water vapor pressure gradient was smaller near the aortal wall and larger in the middle region.

The selection of outgas temperature for shale in low-pressure N2 adsorption: An evidence from thermogravimetry

Low-pressure N2 adsorption (LPNA) could provide quantitative data for characterizing the pores in gas shale. However, the inconsistencies of outgas temperature have caused significant deviations in LPNA experiments. To explore the effects of outgas temperature on pore characteristics, two shale samples of Lower Cambrian Niutitang formation from Northern Guizhou, China, were collected for LPNA experiments and thermogravimetry-fourier transform infrared (TG-FTIR) spectroscopy. The samples were outgassed at six temperatures: 80°C, 100°C, 150°C, 200°C, 250°C, 300°C. Larger adsorbed volumes were presented in the isotherms at higher outgas temperatures. Similar regularity is obtained from the relationship between specific surface area, micropore volume and outgas temperature. Comprehensive analysis of TG-FTIR and LPNA at different outgas temperature indicated that at lower outgas temperatures (from 80°C to 100°C), the free water was unlikely to be removed completely, and resulted in large amounts of micropores couldn’t be accessed. An excessive outgas temperature might expulse liquid hydrocarbons or decompose organic matter (from 200°C to 300°C), and could lead to the generation of micropores. When the sample were outgassed at 150°C, TG-FTIR analysis indicated that the sample composition unchanged and a better removal of free water happened. Therefore, 150°C should be a suitable outgas temperature for shale in LPNA experiments. The findings in this research not only provide reliable evidence for the selection of outgas procedure in LPNA for shale, but clarify the important effects of free water and volatile materials on pore accessibility in shale.

Effect of pre-mechanical compression on free water removal, drying collapses and associated internal voids of oil palm wood

To prevent defects caused by drying collapse, transverse pre-mechanical compression with lateral restraint of green oil palm wood (OPW) before kiln-drying was performed. OPW specimens were divided according to specific gravity into low density (LD 0.22 ± 0.05) and medium-density (MD 0.33 ± 0.02) groups. Effects of compressive strain (0–0.65) and strain rate (0.01–1.0/min) on moisture removal and wood recovery after the compression and on collapse and internal void formations after kiln-drying were investigated. Results indicate that pre-mechanical compression linearly removes moisture out of wood and linearly generates permanent thickness strain that is independent of the strain rate used. The pre-compression reduces the true cross-sectional strain in the kiln-dried LD OPW and MD OPW and the internal voids caused by drying collapse in the LD OPW. The collapse-induced voids, not observed in all kiln-dried MD OPW, disappear when compressive strain > 0.45 is applied to the LD OPW. Microstructural examination reveals that directional folding of parenchyma cells caused by the compression reduces intercellular micro-voids randomly generated during drying by the non-directional collapse of parenchyma cells caused by capillary force. However, above the compressive strains of 0.35 and 0.25 in the LD OPW and MD OPW, interfacial micro-cracks, generated at the boundaries between the parenchyma cells and the fiber bundles, link to form shear bands at the angle of approximately 30–40° to the compression axis. After kiln-drying, these shear bands expand into shear-induced voids. Finally, mechanical properties of the kiln-dried LD OPW pre-compressed at a 0.45 strain without collapse-induced voids are comparable to those that have been air-dried.

Measurement of water fractions in freeze-dried shiitake mushroom by means of multispectral imaging (MSI) and low-field nuclear magnetic resonance (LF-NMR)

The production of high-quality processed foods requires an in-depth understanding of water distribution in cellular spaces. This study validated the non-destructive investigation of water fractions in freeze-dried shiitake mushrooms using multispectral imaging (MSI) at 405−970 nm and low-field nuclear magnetic resonance (LF-NMR). The quantitative modeling of water fractions including partial least squares (PLS), back propagation neural network (BPNN) and least squares-support vector machines (LS-SVM), were employed. The LF-NMR analysis has shown the fast and easy removal of free water owing to weak bonding with tissue structure. Freeze drying left a maximum proportion of bound water and small amount of immobilized water at the end of process. Among the models, LS-SVM demonstrated the highest coefficient of prediction determination (R2p) in the quantitative estimation of water contents and was considered the best model obtaining R2p of 0.85, 0.90, 0.88, and 0.87 plus the lowest root mean square error of prediction of 12.61 %, 7.10 %, 18.13 %, and 4.55 % for free, immobilized, bound, and total water contents, respectively. MSI combined with chemometrics would be a promising technique for the non-destructive and fast monitoring of the water fractions. The findings of this study would be useful to retain the nutritional and quality attributes of agricultural commodities.

Drying Kinetics of a Philippine Nickel Laterite Ore by Microwave Heating

ABSTRACT The microwave drying of a Philippine nickel laterite ore was proposed as an alternative drying method to reduce the air pollution before further pyrometallurgical processing. The effect of thickness of ore bed and microwave power on the specific energy consumption and effective diffusivity were assessed. The results show that the specific energy consumption decreases with increasing the bed thickness and that the specific energy consumption exhibits a minimum at 1200 W. Besides, the increase of nickel laterite thickness and microwave power promotes the effective diffusivity. Compared with the removal of free water, crystalline water removal is proved to be much more energy-intensive. Furthermore, the specific energy consumption in microwave drying of laboratory scale is substantially higher than commercial rotary kiln drying.

Effects of elevated temperature, hydraulic pressure and fatigue loading on the property evolution of a carbon/glass fiber hybrid rod

A carbon fiber core (CFC) and glass fiber shell (GFS) hybrid rod (HFRP) with the diameter of 22 mm was developed to replace the steel rod in the application of underground oil extraction. In the present study, the variation in the properties of the hybrid rod served for 553 days was investigated subjected to the coupling conditions of elevated temperature (T), hydraulic pressure (P) and fatigue load (L)/stress level peak (S), one exposure condition, closed to the ground (T = 25 °C, P = 0.5 MPa, Lmax/S = 70 kN/11.1%) and another in the underground oil-well up to 2600 m (T = 90 °C, P = 18 MPa, Lmax/S = 50 kN/7.9%). Exposed in the deep oil-well condition led to an extra degradation of interface shear strength (ISS) compared to the ground exposure. The degradation mechanism of ISS was attributed to the hydrolysis and plasticization of resin owing to formed multiple hydrogen bonds between the water molecule and chain structures of resin. The removal of free water from the hybrid rod brought about an average increase percentage of ISS, ~10.0% for the upper rod and ~7.4% for the bottom rod. Furthermore, the maximum recovery of ISS was observed for the removal of bound water for the drying at 100 °C for 14 days. The fatigue performance evaluation of hybrid rod exposed in underground oil-well condition showed the optimal rod diameter for the present fatigue load condition (Lmax/S = 70 kN/11.1%) was 19 mm with the service life of ~50 years. Furthermore, the applied maximum fatigue load was obtained to be 114.3 kN with the fatigue life of 22.6 years for the present hybrid rod.

Evaluation of free water removal from different sludge by solar energy utilization

Evaluation of free water removal from different sludge by solar energy utilization

Influence of Drying on the Microstructure of Hardened Cement Paste: A Mercury Intrusion Porosimetry, Nitrogen Sorption and SAXS Study

Since the durability of concrete depends on the paste matrix, a sound knowledge of its pore structure is required. The most common methods to investigate the microstructure like mercury intrusion porosimetry (MIP) and gas sorption require the removal of free water in the pore space. However, the different drying methods used for this task either do not remove all free water or remove also chemically bound water and thus alter the microstructure. Small-angle X-ray scattering (SAXS) is one of the rare methods which allows to investigate the microstructure without complete water removal. Therefore, in order to compare the effect of different drying methods on the pore structure, hardened OPC paste samples (w/c = 0.5) were investigated with MIP, nitrogen sorption and for the first time with SAXS, after different drying was carried out. Since specific surfaces obtained for SAXS showed a similar trend as for MIP and nitrogen sorption, it can be concluded that SAXS can be utilized to predict the influence of drying on these methods as well. Solvent exchange appears to be a drying method that preserves the microstructure well, since for this the largest specific surface was obtained.

Effect of Modified Tapioca Starch on Mechanical, Thermal, and Morphological Properties of PBS Blends for Food Packaging.

In this study, polybutylene succinate (PBS) was blended with five types of modified tapioca starch to investigate the effect of modified tapioca starch in PBS blends for food packaging by identifying its properties. Tensile and flexural properties of blends found deteriorated for insertion of starch. This is due to poor interface, higher void contents and hydrolytic degradation of hydrophilic starch. FTIR results show all starch/PBS blends are found with footprints of starch except OH stretching vibration which is absent in B40 blends. Besides, Broad O–H absorption in all specimens show that these are hydrogen bonded molecules and no free O–H bonding was found. SEM testing shows good interfacial bonding between PBS and starch except E40 blends. Therefore, poor results of E40 blends was expected. In TGA, a slightly weight loss found between 80 to 100 °C due to free water removal. Apart from this, insertion of all types of starch reduces thermal stability of blend. However, high crystallinity of starch/PBS blend observed better thermal stability but lower char yield. Starch A and B blends are suggested to be used as food wrap and food container materials while starch D blend is suitable for grocery plastic bags according to observed results.

Drying kinetics of Philippine nickel laterite by microwave heating

ABSTRACTIn this study, microwave heating was used to dry nickel laterite, which contains significant quantities of free water, crystal water, and hydroxy water. The results show that the main phase of crystal water is Ca3Al6Si10O32(H2O)13, and the main phases of hydroxy water are FeO(OH) and Mg5(Al, Cr)AlSi3O10(OH)8. The microwave drying process of nickel laterite can be divided into two stages: the removal of free water and the coupled removal of free water, crystal water, and hydroxy water. The effect of particle size and microwave power output were studied, and these indicate that the drying time and specific energy consumption decrease with increasing particle diameter and microwave power. The effective diffusivity and activation energy were calculated, and these are larger in the second stage than that in the first stage. The activation energies are 27.66 and 32.80 W/g for the first and second stages, respectively. The phase transition of the product, schematic drying mechanism, and feasibility analysis of the microwave drying process are also discussed.

Moisture removal mechanism of low-rank coal by hydrothermal dewatering: Physicochemical property analysis and DFT calculation

High moisture content greatly restricts the large-scale utilization of low-rank coals (LRCs). Hydrothermal dewatering (HTD) is a promising technique for dewatering and upgrading LRCs. Chinese lignite from XiMeng Mine in Inner Mongolia was upgraded by HTD. The effects of pore structure and oxygen functional group content on moisture distribution were investigated. Thermogravimetric analysis, mercury intrusion porosimetry, and chemical titration were conducted to characterize the physicochemical properties of coal samples. Results show that a substantial amount of moisture was removed, the coal composition was modified, and the energy density was significantly improved after HTD. Both free-phase and bound-phase moisture in lignite were significantly removed. Free water removal was associated with the collapse of macropore structures caused by shrinkage forces. The bound water was remarkably reduced as a result of the removal of oxygen functional groups, such as phenolic hydroxyl and carboxyl. During HTD, the oxygen functional groups were decomposed, and the hydrogen bonding between water and hydrophilic sites was destroyed, thereby leading to a weakening of the water-holding capacity of lignite. Four representative model molecules with different polarities were used to study the intermolecular interactions between lignite and water. The interaction energies of model molecule⋯water complexes were determined by density functional theory (DFT) calculation. The types of non-covalent interactions of both hydrophobic and hydrophilic sites in lignite with water were vividly demonstrated using color-mapped reduced density gradient isosurface. The carboxyl and hydroxyl groups are extremely liable to interact with water via hydrogen bonding with large interaction energy and exhibiting strong hydrophilicity. On the other hand, the alkanes and benzene rings interact with water via van der Waals attractions and show hydrophobic effects.

Laser scabbling of mortars

Laser scabbling of concrete is the process by which the surface layer of concrete may be removed through the use of a low power density laser beam. Previous research has suggested that the driving force responsible for laser scabbling is developed within the mortar. The aim of this investigation was to establish the key parameters that influence laser scabbling of mortars. The results show that the removal of free water from mortars prohibits scabbling, but resaturation allows mortar to scabble. A reduced permeability, either due to a reduction in the water/binder ratio or the use of 25% PFA replacement, enhances the scabbling. A higher fine aggregate content increases volume removal and fragment sizes during laser scabbling.