Insoluble Sludge Research Articles

Multiscale Modeling Approach to Understand Mechanism of Deposit Control by Sulfonate-Based Lubricant Detergents.

Protecting the material surfaces from deposits and insoluble sludge particles extends the engine life and reduces waste. Lubricant detergents in engine oils are essential additive technologies that prevent deposit formation in internal combustion engines. In this study, the effect of sulfonate detergent on deposit formation in a passenger car engine is investigated with experimental and multiscale molecular modeling methods to present a unified approach. First principles density-functional theory calculations, statistical sampling methods, all-atom molecular dynamics simulations, and coarse-grained simulations are examined to elucidate deposit control mechanism of sulfonate detergents. Analysis of the results reveals that sludge particles in the drain oil are similar in structure to piston deposits, and they might be the precursors of the piston deposits. Main factor for controlling the sludge particle deposition is the prevention of their colloidal aggregation at the microscale in the base oil matrix. Aggregation can be mitigated by the intercalation of detergent polar groups between the particles. This is followed by the extension of hydrophobic tails into the oil phase, which decreases further aggregation via formation of a repulsive layer.

Rationale of the dielectrometric method of definition of lubricant oils' tribological characteristics' changes

The article demonstrates the contradiction of generally accepted methods of research of lubricants tribological properties on the example of spent oil studies and critically considers the possibility of using the obtained results as criteria for assessing the serviceability of lubricating oils after a certain service life. In particular, regulatory parameters such as viscosity, flash point, acid value and insoluble sludge content were considered. Viscosity, in particular, was assessed by the Heppler’s and the Ostwald’s methods. As a result, it was found that the first of these methods shows lower values. Similar ambiguity is demonstrated by normative methods for determining the flash point in open and closed crucibles, determining the acid number by potentiometric or calorimetric titration of an oil sample dissolved in various solvents and determining the sludge content by extraction with n-pentane, n-heptane and extraction benzene. As it turned out, the results obtained by different methods are impossible to compare. The analysis of the obtained data also confirms the opinion that the indicators determined in the laboratory have no practical application, because they do not correlate with the real operating conditions of the oil. Such laboratory studies can only be used to compare two or more samples of lubricants. As an objective criterion that would reflect the interaction of the components of lubricating oils and friction units during operation and could serve as an indicator of the degree of aging of the oil, the author proposed to use the dielectric constant in an alternating electric field. These first research results show that changes in dielectric constant as a function of service life can be considered an indicator of the degree of aging of the oil, and the results allow us to estimate the concentration of sludge and mechanical contaminants in oils. However, given the multicomponent nature of modern oils and the influence of other factors on the dielectric penetration of the material, the results obtained should be considered only preliminary and those that require further refinement and processing.

Solid state and phase transformation mechanism of kaolin sintered with limestone for alumina extraction

The present work aims to investigate the effects of the solid-state thermal reactions at different sintering temperatures on the phase transformation mechanisms and the microstructural changes, the self-disintegration mechanism as well as the efficiency of alumina percent recovery during alumina extraction from kaolin by the lime-sinter process. The sinters were produced at different temperatures within the range 800 °C - 1400 °C then subjected to leaching process (at the optimum dissociation of 1:5 solid : liquid ratio) by using sodium carbonate solutions (120 g/L) which finally were given to the alumina-pregnant solution. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used for characterizing the transformational changes resulted during the thermal reactions between the sintered mineral components in the raw kaolin and limestone samples (i.e., kaolinite and calcite). Microstructural and textural changes of the obtained sinters and sludges were characterized by means of X-ray diffractometry (XRD/XRF), scanning electron microscopy (SEM/EDX) and particle size granulometry. The results indicated that the sintering temperature at 1360 °C was the optimum for inducing of the solid-state reaction between the clay and carbonate components with enhancement of alumina productivity by the highest recovery (80.49%). At this superlative sintering condition, the kaolinite was dehydroxylated and transformed into metakaolinite while the calcite was decomposed into calcium oxide, then they reacted together forming to the calcium aluminates that are considered as the highly effective and generative precursor phases in the alumina extraction. Moreover, the obtained sludges were obviously exhibited morphological changes with size enlargements during the leaching process due to the formation of calcium carbonate particles that agglomerated at the surfaces of the insoluble sludge particles.

Characterization of the Insoluble Sludge from the Dissolution of Irradiated Fast Breeder Reactor Fuel

Insoluble sludge is generated in the reprocessing of spent fuel. The sludge obtained from the dissolution of irradiated fuel from the “Joyo” experimental fast reactor was analyzed to evaluate its chemical form. The sludge was collected by the filtration of the dissolved fuel solution, and then washed in nitric acid. The yields of the sludge weight were less than 1% of the total fuel weight. The chemical composition of the sludge was analyzed after decomposition by alkaline fusion. Molybdenum, technetium, ruthenium, rhodium, and palladium were found to be the main constituent elements of the sludge. X-ray diffraction patterns of the sludge were attributable to Mo4Ru4RhPd, regardless of the experimental conditions. The concentrations of molybdenum and zirconium in the dissolved fast reactor fuel solutions were low, indicating that zirconium molybdate hydrate is produced in negligible amounts in the process.

Simultaneous Recovery of Protein and Polysaccharide from Abalone (Haliotis discus hannai Ino) Gonad Using Enzymatic Hydrolysis Method

Abalone gonad, the major processing by-product, contains many useful components beneficial to health such as polysaccharides, proteins (peptides) and lipids. In the present study, the distribution of dry matter, protein, polysaccharide and lipid between the three centrifuged phases (sludge, aqueous and lipid phases) of the hydrolysates from abalone (Haliotis discus hannai Ino) gonad was investigated to reveal the possibility for the simultaneous recovery of the valuable components. Before hydrolysis, the dry matter, protein and sugar distributing in insoluble sludge phase were 82.05, 89.12 and 60.65% of their total amounts. After 4 h of hydrolysis, the corresponding values were reduced to 56.28, 55.47 and 31.64% for neutral protease-hydrolyzed abalone gonad, and were reduced to 57.60, 50.82 and 36.25% for alkaline protease-hydrolyzed abalone gonad. The results indicated that enzymatic hydrolysis caused the solubilization of proteins and polysaccharides from the substrate, and the two valuable components could be recovered from the soluble matters simultaneously.

Pyrosequencing Reveals the Key Microorganisms Involved in Sludge Alkaline Fermentation for Efficient Short-Chain Fatty Acids Production

Short-chain fatty acids (SCFAs) have been regarded as the excellent carbon source of wastewater biological nutrient removal, and sludge alkaline (pH 10) fermentation has been reported to achieve highly efficient SCFAs production. In this study, the underlying mechanisms for the improved SCFAs production at pH 10 were investigated by using 454 pyrosequencing and fluorescent in situ hybridization (FISH) to analyze the microbial community structures in sludge fermentation reactors. It was found that sludge fermentation at pH 10 increased the abundances of Pseudomonas sp. and Alcaligenes sp., which were able to excrete extracellular proteases and depolymerases, and thus enhanced the hydrolysis of insoluble sludge protein and polyhydroxyalkanoates (PHA). Meanwhile, the abundance of acid-producing bacteria (such as Clostridium sp.) in the reactor of pH 10 was also higher than that of uncontrolled pH, which benefited the acidification of soluble organic substrates. Further study indicated that sludge fermentation at pH 10 significantly decreased the number of methanogenic archaea, resulting in lower SCFAs consumption and lower methane production. Therefore, anaerobic sludge fermentation under alkaline conditions increased the abundances of bacteria involved in sludge hydrolysis and acidification, and decreased the abundance of methanogenic archaea, which favored the competition of bacteria over methanogens and resulted in the efficient production of SCFAs.

Electrochemical micro-drilling of deep holes by rotational cathode tools

In numerous non-conventional micro-machining, electrochemical micro-machining has merits such as high removal rate, leaving no residual stress and lower roughness on surfaces of machined products. It has been considered as a highly promising technology in micro-machining. Little research has been done on the deep-hole micro-drilling by electrochemical methods. This work utilizes a rotational system to extract insoluble sludge from a deep hole and reduce the difficulty of filling deep hole with electrolyte. As well as a rotational tool cathode, a pulsed power generator is used to support the intermittence machining to increase the precision of the workpiece. The influence of working parameters, such as pulsed on-times, applied voltages, electrolyte concentrations, pulsed frequencies, tool feeding rates, tool diameters, tool rotational rates, and hole depth, on the hole overcut and conicity in a electrochemical micro-drilling is investigated. A high quality micro-hole with a 33.35-µm overcut is drilled by a tungsten carbide pin of diameter 50 µm on a 304 stainless steel plate of thickness 1,000 µm. The hole aspect ratio (depth/diameter) reaches 8.6. It shows that a rotational tool can be utilized in the deep-hole electrochemical micro-drilling.

Enzymatic hydrolysis of cuttlefish (Sepia officinalis) and sardine (Sardina pilchardus) viscera using commercial proteases: Effects on lipid distribution and amino acid composition

Total lipid and phospholipid recovery as well as amino acid quality and composition from cuttlefish (Sepia officinalis) and sardine (Sardina pilchardus) were compared. Enzymatic hydrolyses were performed using the three proteases Protamex, Alcalase, and Flavourzyme by the pH-stat method (24 h, pH 8, 50 degrees C). Three fractions were generated: an insoluble sludge, a soluble aqueous phase, and an oily phase. For each fraction, lipids, phospholipids, and proteins were quantified. Quantitative and qualitative analyses of the raw material and hydrolysates were performed. The degree of hydrolysis (DH) for cuttlefish viscera was 3.2% using Protamex, 6.8% using Flavourzyme, and 7% using Alcalase. DH for sardine viscera was 1.9% (using Flavourzyme), 3.1% (using Protamex) and 3.3% (using Alcalase). Dry matter yields of all hydrolysis reactions increased in the aqueous phases. Protein recovery following hydrolysis ranged from 57.2% to 64.3% for cuttlefish and 57.4% to 61.2% for sardine. Tissue disruption following protease treatment increased lipid extractability, leading to higher total lipid content after hydrolysis. At least 80% of the lipids quantified in the raw material were distributed in the liquid phases for both substrates. The hydrolysed lipids were richer in phospholipids than in the lipids extracted by classical chemical extraction, especially after Flavourzyme hydrolysis for cuttlefish and Alcalase hydrolysis for sardine. The total amino acid content differed according to the substrate and the enzyme used. However, regardless of the raw material or the protease used, hydrolysis increased the level of essential amino acids in the hydrolysates, thereby increasing their potential nutritional value for feed products.

Metal Content and Physicochemical Parameters Used as Quality Criteria in Virgin Argan Oil: Influence of the Extraction Method

Metal content was determined in 26 samples of virgin argan oil from Morocco. An ETA-AAS with previous sample dilution with MIBK technique was used. In oil obtained by traditional method, Fe ranged from 0.8 to 4.0 mg/kg, Cu from 160.4 to 695.7 microg/kg, Cr from 10.3 to 55.3 microg/kg, Mn from 18.1 to 70.8 microg/kg, and Pb from 28.5 to 450.0 microg/kg. In oil obtained by a half-industrialized method, Fe ranged from 0.8 to 1.7 mg/kg, Cu from 158.4 to 385.0 microg/kg, Cr from 10.0 to 48.1 microg/kg, Mn from 15.0 to 68.5 microg/kg, and Pb from 32.0 to 100.0 microg/kg. Acidity value, peroxide index, K270 and K232, humidity and sludge volatile, and insoluble sludges in petroleum ether were also determined. A high variability in these quality parameters and a decrease of the quality in the oils obtained by the traditional method were observed.

Hydrolysis of Cod (Gadus morhud) By-Products

The main aim of hydrolysis of by-products is to obtain the highest possible amount of valuable components. Backbones and liver from farmed cod (Gadus morhua)were hydrolyzed and effect of different factors such as initial inactivation of endogenous enzymes, dilution prior to hydrolysis and centrifugation conditions on the yield and functional properties of the different fractions was evaluated. Samples with active endogenous enzymes gave significantly higher dry yields of emulsion, fish protein hydrolysate (FPH) and reduced dry yield of sludge. In the presence of both active endogenous and commercial enzymes, yield of dried FPH was higher than yield of dried sludge. Yield of protein containing fractions was more dependent on the initial heating of the system than on amount of added water. Centrifugation forces were important for separation of oily fractions, but not for separation of protein fractions. The oil and emulsion fractions consisted mainly of triglycer-ides, while phospholipids were found mostly in the protein containing fractions. The insoluble sludge contained a high amount of lipids (up to 30%) including a high content of phospholipids (up to 46%).

The fluoborate treatment of sludge from the electrolytic refining of granulated lead

Recovering lead electrolytically from granulated blast furnace bullion offers the potential for significant financial and environmental benefits. A fluoborate pilot plant (a modification of the Fluobor® process) successfully demonstrated that ferric-fluoborate leaching of bullion followed by electrowinning of the purified leach solution could produce commercial-grade lead. In order to recover other metals of value, especially precious metals, from the insoluble sludge, a new hydrometallurgical process was simultaneously studied and the proposed process was integrated into the overall flow sheet.

Rapid-extraction oxidation process to recover and reuse copper chromium and arsenic from industrial wood preservative sludge

Chromated copper arsenate (CCA) wood preservative can form insoluble sludges when the hexavalent chromium component is reduced by wood extractives, wood particles and preservative additives in the solution. This sludge accumulates in treating solution work tanks, sumps and in-line filters and must be disposed of as hazardous wastes by waste disposal companies at high costs. A number of commercial sludges were investigated and found to contain 18–94% copper, chromium and arsenic as oxides combined with sand, oil, wood particles, additives and wood extractives. We have developed a multi-stage recycling process whereby approximately 97% of the CCA components are recovered from the sludge. It involves extraction with sodium hypochlorite to remove and oxidize chromium (more than 90%) and extract most of the arsenic (approx. 80%) followed by extraction of the copper and remaining arsenic and chromium with phosphoric acid. The phosphoric acid extract contains some trivalent chromium, which is subsequently oxidized by sodium hypochlorite. The combined oxidized extract containing Cr VI, Cu II and As V was compatible with CCA treating solutions and could be re-used commercially for treating wood without having a significant effect on the preservative fixation rate or the leach resistance of the treated wood. A cost analysis showed that the economic savings from recovery of CCA chemicals and reduced landfill costs exceeded the variable costs for materials and energy for the process by as much as Can $966 per tonne of sludge if sodium sulfite can be acquired in bulk quantities for the process.

Colloidal Agglomerates in Tank Sludge and Their Impact on Waste Processing

AbstractDisposal of millions of gallons of existing radioactive wastes in underground storage tanks is a major remediation activity for the United States Department of Energy. These wastes include a substantial volume of insoluble sludges consisting of submicron colloidal particles. Processing these sludges under the proposed processing conditions presents unique challenges in retrieval transport, separation, and solidification of these waste streams. Depending on processing conditions, these colloidal particles can form agglomerated networks having high viscosities that could clog transfer lines or produce high volumes of low-density sediments that interfere with solid-liquid separations. Under different conditions, these particles can be dispersed to form very fine suspended particles that do not settle. Given the wide range of waste chemistries present at Department of Energy sites, it is impractical to measure the properties of all treatment procedures. Under the current research activities, the underlying principles of colloid chemistry and physics are being studied to predict and eventually control the physical properties of sludge suspensions and sediment layers in tank wastes and other waste processing streams. Proposed tank processing strategies include retrieval transport, and solid-liquid separations in basic (pH 10 to 14), high ionic strength (0.1 to 1.0 M) salt solutions. The effect of salt concentration, ionic strength, and salt composition on the physical properties such as viscosity, agglomerate size, and sedimentation of model suspensions containing mixtures of one or two of the major components found in actual wastes have been measured to understand how agglomeration influences processing. Property models developed from theory and experiment on these simple suspensions are then applied to explain the results obtained on actual wastes.

Diagnosis of the condition of diesel engines in city buses on the basis of used oil analyses

-- in 10% of the oil samples, the content of water was higher than that characteristic for an engine with a tight cooling system when the engine is in good condition, i.e., more than 0.03% water; -- the viscosity of 4% of the samples was below the viscosity of the fresh oil, indicating dilution of the oil with fuel and malfunctions in the engine fuel system; -- in 30% of the samples, the oil had no dispersancy or stabilizing properties as determined by paper chromatogaphy; in three cases, the used oil had an unduly high water content; in two cases, the oil change period had been exceeded (samples at the time of oil change were taken every 7-13 thousand kilometers of bus travel); and in practically all of the oil samples, high concentrations were noted for the elements indicating wear of engine parts; -- in 60% of the samples, the silicon content was high (this element characterizes not only wear of parts made of silicon-containing alloys, but also access of unfiltered air to the engine; In 4% of the samples, the contents of iron, copper, and lead were high, with relatively low silicon concentrations, possibly because of breakdown of the working surfaces of rubbing parts made of bearing alloys (grooving, increased wear). With high concentrations of silicon in the used oil, we also noted significantly increased contents of iron, aluminum, and chromium, and to a lesser degree lead and copper. In particular, with an increase of the silicon concentration in the oil from 3-70 ppm to 500-1000 ppm, the contents of iron and aluminum increased by two orders of magnitude, and the contents of lead, copper and chromium by one order of magnitude. Such large increases of metal contents are characteristic for diesel operation when the air cleaning system is not functioning properly, as this leads to wear rates that are several tens of times higher, particularly for the cylinder-piston group. The end results are higher oil consumption in burning, increased exhaust smoke, and poorer power characteristic of the transport vehicles. In a number of cases, with high concentrations of silicon and wear-indicating elements, the following were noted: Increased content of insoluble sludge up to 5-6% and incombustible products up to 0.7-0.8%; increased viscosity up to 19 mm2/sec at 100~ absence of dispersant and stabilizing properties. All this is typical of wear damage in the piston/cylinder group of diesel engines [6]. The large volume of work that has been performed has made it possible to apply a method set forth in [6] to calculate the limiting values of wear-indicator element concentrations corresponding to good and poor working condition for the diesels RABA-MAN D 2356 HM6 in Icarus 260.50 and Icarus 280.64 buses.

Viscosity of marine diesel oils and changes of viscosity in the course of aging

The work reported here was aimed at predicting changes in the viscosity of marine diesel oils during the operation of engines that are in good condition, in order to obtain baseline relationships between the viscosity and the content of insoluble products of oil aging. The use of these relationships as standards will provide a sounder basis for interpreting the results of viscometric analysis. Many studies have been reported on the influence of oil aging on oil viscosity. The main factor influencing the increase of oil viscosity is contamination of the oil with insoluble sludge. A certain increase of viscosity also takes place as a result of the formation of oil oxidation products. Some of these products are insoluble in the oil and are regarded as a solid phase. The remainder of the products - oxidized hydrocarbons, alcohols, aldehydes, ketones, and other compounds - are soluble in oil at the temperatures prevailing in the crankcase, and these are also capable of increasing the oil viscosity. According to our experimental data, the share of the oxidation component in the total increase of viscosity is no greater than 10%; this is consistent with results obtained previously in (5-18%).

Effect of oxidation products on service properties of motor oils

One of the most urgent problems in chemmotology is how to create in an engine - lube oil system a controllable tribochemical process for the purpose of stabilizing the service properties of the oil and forming protective surface structures on the engine parts in order to minimize wear. The complexity of this problem reflects the diversity of the processes taking place in the tribological system. It is impossible to elucidate the mechanism of tribochemical reactions without studying the influence of changes in the oil composition and structure on its service properties during the course of operation. If the relationships involved in this influence are defined, it will become possible to change the structure of the oil in the desired direction and to achieve the desired service properties. For our studies we selected the motor oil M-10-G{sub 2}, conforming to GOST 8581-78. Samples of this oil were drawn during test-stand evaluations of D-144 and D-144-60 tractor diesels without any oil changes these tests were conducted jointly by the Institute of Problems in Mechanical Engineering of the Russian Academy of Sciences, the Scientific-Research and Design-Technology Institute of Tractor and Combine Engines (NIKTID), and the Vladimir Tractor Plant Production Association. Tests were runmore » for 1000 h with the standard conditions and test sequence, and for 1500 and 2300 h under conditions of a {open_quotes}constantly acting tribochemical regime{close_quotes}. Oil samples were drawn at 50-100 h intervals and tested by standard methods to determine the following physico-chemical characteristics: kinematic viscosity, acid and base numbers, ash, carbon residue, content of insoluble sludge, and content of particulate contaminant.« less

Total Effluent Treatment and Rinse Water Reclamation in a Semiconductor Device Manufacturing Facility

Case history of a total rinse water reclamation system operating in a semiconductor manufacturing facility. Utilizing the latest technologies, over 90% of the rinse water is purified back to 18 megohm/cm quality for reuse, and the concentrated toxic chemicals are precipitated and disposed of as an insoluble sludge. Based on a maximum rinse water flow of 72,000 gallons per day, the total operating cost is $251. 31/day.

Influence of polycyclic aromatic hydrocarbons on thermal-oxidative stability of hydrocracked oils

stability of the oils was determined in a GOST JAil-Union State Standard) universal instrument at 200~ with an air throughput of 150 ml/min and an oxidation period of 40 h, with lead and copper strips as catalysts. The oil stability was judged by the quantity of insoluble sludge formed in the oil upon oxidation and by the changes in viscosity and acid number of the oil during the oxidation period. Of the seven hydrocracked oils that were investigated, five (Nos. 2, 3, 4, 5, and 7) proved to be stable, forming no more than 0.5% oil-insoluble sludge upon oxidation. Samples 1 and 6 were unstable, forming about 23% sludge (Table 2). With the aim of investigating the influence on thermal-oxidativ e stability of individual groups of hydrocarbons, an oxidation-unstable oil (sample I) was separated into hydrocarbon groups, i.e., paraffins/naphthenes, aromatic hydrocarbons with n~ ~ 1.4800-1.5300, 1.5300- 1.5900, and above 1.5900, and resins. These segregated hydrocarbon groups were reblended to make up a series of mixtures of paraffinic/napht henic and aromatic hydrocarbons (Table 3). Included for comparison were samples of paraffinic-napht henic hydrocarbons from a solvent- treated oil and from hydrocracked oils, these hydrocarbons being stable to oxidation. The oxidation stability of the paraffinic/napht henic hydrocarbons was found to be identi- cal for all the oils investigated; the sludge content was no greater then 0.3%, and the vis- cosity increase was within the limits of 110-133%. In blends 2-4 (see Table 3), the paraffinic naphthenic hydrocarbons were blended with successive amounts of the various classes of aromatic compounds to match the contents in the original oil sample i. The addition of aromatic hydrocarbons with n~ ~ = 1.4900-1.5300 (blend 2) gave a slightly greater viscosity increase but did not produce any sludge in the oxidation test. The aromatic hydrocarbons with n~ ~ = 1.5300-1.5900 (blend 3) likewise had no serious effect on the product properties. However, when the aromatic hydrocarbons with n~ ~ above 1.5900 were also added to the oil, i.e., when the original oil composition with the exception of the resins was reconstituted (blend 4), the product was much poorer in thermal-oxidativ e

Evaluation of PCV Systems by Field and Full-scale Laboratory Tests

The effects of PCV systems of domestic gasoline engines on performance of crankcase oils were studied by taxicab field tests and laboratory full-scale tests. These tests were run on three types of crankcase ventilation systems; road draft type, tube type PCV and valve type PCV. Three grades of crankcase oils, MM, MS and Supplement-1 class, were used.The results obtained are as follows:(1) Tube type PCV system showed a marked tendency to form a lot of oil insoluble sludge than valve type PCV system and road draft system.(2) The combined additive formulations of ashless dispersants and metal salts detergents were effective to control sludge formation in the three crankcase ventilation systems.(3) The NOC MS Test (modified MS Sequence V Test procedure using OHV Type engine) could utilize satisfactorily for the studies of the effect of crankcase ventilation systems and the evaluation of crankcase oils.