Viscosity-temperature Characteristics Research Articles

Investigation of rheological properties and modification mechanism of SBS-modified asphalt with different warm mix additives

ABSTRACT The application of warm mix asphalt (WMA) technology in polymer-modified asphalt becomes increasingly widespread, but it lacks thorough investigation on the interaction mechanism between warm mix additives and polymers. Accordingly, two new warm mix additives, an organic viscosity-reducing modifier (A) and a surfactant-based modifier (C), were selected to prepare the warm mix SBS-modified asphalt. The basic properties, viscosity-temperature characteristics, ageing resistance and rheological properties of modified asphalt were tested. At last, the modification mechanism was elucidated through a series of microscopic tests. The results indicated that A could more effectively enhance the construction workability of SBS-modified asphalt, while C had little effect on its basic properties. Both new modifiers, especially A, reduced the high-temperature property of asphalt, with partial recovery after short-term ageing. The microstructure test results indicated that the two modifiers were physically modified with SBS-modified asphalt. Both additives improved the dispersion uniformity of SBS particles in asphalt, and the microscopic morphology parameters obtained from quantitative analysis reflect the macroscopic properties of asphalt. Moreover, the light components and rubber powder of A improved the flexibility of asphalt, and C enhanced its low-temperature performance, which demonstrated that these two modifiers were more suitable for asphalt pavements in cold regions.

Effect of styrene butadiene styrene and desulfurized rubber powder on asphalt modification: Preparation, performance enhancement, mechanism analysis

The aim of this study is to propose a desulfurized rubber powder / styrene butadiene styrene (DRP/SBS) composite modified asphalt technology by combining the advantages of DRP and SBS. This reduces the production cost of modified asphalt and improves the performance of asphalt. In this paper, orthogonal tests were used to optimize preparation process parameters of DRP/SBS composite modified asphalt. And the physicochemical properties, modification mechanism of composite modified asphalt had been thoroughly studied. Subsequently, the results showed that the optimum content of DRP and SBS modifiers are 25 % and 2 %, respectively. The suitable preparation process is to add SBS first, then DRP, while shearing at 5000 r/min for 50 min. In addition, DRP/SBS composite modified asphalt has better high-temperature performance, viscosity-temperature characteristics, aging resistance, and storage stability. Meanwhile, the storage stability of the composite modified asphalt was verified by fluorescence microscopy test. Through the Fourier transform infrared spectroscopy test, it was observed that the composite modified asphalt modification process is a compatible and stable modification of physical and chemical coexistence. Overall, the composite modification method achieves recycling of waste tires while improving pavement performance, thus promoting the sustainability of pavement.

Dynamic Viscosity-Temperature Characteristics and Models of Various Lubricating Oils

Background: The dynamic viscosity - temperature characteristics of lubricants are the main factors used to determine the oil film thickness and carrying capacity. There are few studies on the factors affecting the dynamic viscosity-temperature characteristics of lubricating oils and the dynamic viscosity-temperature model. Objective: This research aims to analyse the influences of lubricating oil type and initial kinematic viscosity on dynamic viscosity - temperature characteristics and present a new dynamic viscosity - temperature model. Methods: The characteristic curves of dynamic viscosity versus temperature of polyol ester oil, paraffinic mineral oil, and five types of PAO (poly a-olefin) oils with different initial viscosities were obtained by using a kinematic viscosity test device and a density test device. The influences of lubricating oil type and lubricating oil viscosity on dynamic viscosity - temperature characteristics were analysed. Based on our patent technology and repeated verification, a new dynamic viscosity - temperature model was presented. Results: Viscosity - temperature curves of three different types of lubricating oils and viscosity - temperature curves of PAO oils with different initial kinematic viscosities were obtained. A new dynamic viscosity - temperature model η=A×e^(((-T)/n) )⁡+ η_0 was proposed. Conclusion: The dynamic viscosity - temperature characteristics of lubricating oils are not only determined by the type of oils but also determined by the initial kinematic viscosity.The variation of dynamic viscosity of lubricating oils with temperature in the scope of -40~110℃ can be described by the following viscosity temperature model : , which can be used in wider temperature range than the existing models.

Exploring influence of MgO/SiO2 on viscosity-temperature property of coal ash slags under entrained flow gasification condition

To realize smooth slag discharge of Zhundong coals in entrained-flow-bed gasifier, the viscosity-temperature characteristics of slags with different MgO/SiO2 ratios were studied. The results show that low MgO/SiO2 ratio causes high BO content in liquid slag, resulting in excessive polymerization degree and viscosity. As the MgO/SiO2 increases, the activation energy of liquid slag increases, occurrence form of oxygen transforms from BO to NBO, more structural depolymerization reactions occur, and [SiO4] tetrahedra obtains more O2− and show more NBO. NBO is more likely to react with Mg2+, Ca2+, Al3+, and Fe2+ to form crystals, thus increasing the crystallization reaction activity of slag and cause the initial crystallization temperature and crystal content increasing. An increasing MgO/SiO2 causes a characteristic transition of slag from weak crystallinity and high polymerization degree to strong crystallinity and low polymerization degree, meanwhile, the poor viscosity-temperature characteristics with high viscosity of liquid slag is first improved, and then the problem of strong crystallinity leading to poor viscosity-temperature characteristics with high Tcv occurs. Therefore, the viscosity-temperature characteristics first improve and then deteriorate. The crystal size increases as MgO/SiO2 increases, which also cause Tcv increasing. Large ΔT and low Tp25 make 0.28MS become the most suitable for slag discharge.

Effects of sludge on the ash fusion behaviors of high ash-fusion-temperature coal and its ash viscosity predication

The co-gasification of sludge and coal is a promising way to regulate coal ash fusion characteristics and recover energy from sludge simultaneously. In this paper, the ash fusion behaviors of high ash-fusion-temperature (AFT) Datong coal, textile dyeing sludge (TDS), their mixtures, and the corresponding AFT modification mechanisms on laboratory scale were investigated by an AFT tester, X-ray diffractometer, Raman spectrometer, and FactSage software. The AFTs of Datong coal mixtures decreased slowly when TDS share was in the range of 0–6%, quickly (6–9%), and then nearly stable (>9%) because of its corresponding increasing basic oxide values (the total content of SO3, CaO, MgO, Fe2O3, Na2O, and K2O). The generations of low melting-point minerals of hercynite and anorthite with TDS additions resulted in the AFT decrease. The decreasing intensity of Si–O–Si peak and the increasing ratio bond of bridging oxygen and non-bridging oxygen led to the AFT decrease. Both the decreases in the temperature at which all minerals change into liquid-phase and the continuously increasing liquid-phase content (at the same relative high temperature) in Datong coal mixed ashes with increasing TDS mass ratio were contributed to the variations of AFT. The viscosity-temperature characteristics variation was also predicted using FactSage calculation. The 9.0–12.0% mass ratio of TDS might be suitable for Datong coal entrained-flow bed gasification.

Biomass Entrained Flow Gasification Technology and CFD Numerical Simulation

Aiming at the dry pulverized biochar fuel refined by thermochemical conversion technology, its properties were obtained through experiment. By blending 5% additives to improve the ash fusion characteristics of biomass particles and considering the viscosity-temperature characteristics and the matching principle of CO2 reaction activity, the entrained flow gasification technology scheme of biomass particles was formulated. Based on the gasification reaction kinetics of dry pulverized biochar, a numerical simulation model was established to predict the flow characteristics, syngas composition, and particle conversion process in the gasifier. The results show that under the swirling entrainment and centrifugal force, the oxidizing reaction of particles is completed in the upper part of the gasifier quickly after mixing with oxygen. And the gasification reduction reaction occurs in the recirculating area and the pipe flow area. These effectively complete the conversion of char. The simulation results are in good agreement with the equilibrium calculation values, which proves the feasibility and rationality of the biomass particle entrained flow gasification technology scheme based on the HT-L.

Synergistic effects and mechanism of the ternary flux system Fe2O3-CaO-MgO on the coal ash slag fluidity

Basic oxides are usually widespread in low-rank coals and cause many ash-related problems in gasification applications. In this paper, the synergistic effects of the ternary flux system of Fe2O3-CaO-MgO in lowering the ash fusion temperature and improving the viscosity-temperature characteristics were verified by testing the properties of samples with different Fe2O3/(CaO + MgO) ratios. The flow temperatures and temperatures of the critical viscosity decreased and then increased with the decrease of Fe2O3/(CaO + MgO) ratio and reached the lowest point when the iron oxide and alkaline earth metal oxide (CaO, MgO) contents were close to each other. From the perspective of mineral transformation, the formation of low melting point ferroan spinel and the eutectic between anorthite and ferroan spinel are the main mechanisms of synergism. No severe crystallization was observed in the iron-rich slags because Fe2+ could reduce the crystallization tendency. As CaO and MgO dominated the basic oxides, a CaO/MgO ratio of 4:6 effectively limited the crystallization and lower the temperature of critical viscosity (TCV). Thus, when regulating the coal ash fluidity, the content of iron oxide and the ratio between CaO and MgO should be consciously balanced to meet the requirements of the gasifier for slag removal.

Study on Slagging Characteristics of Co-Combustion of Meager Coal and Spent Cathode Carbon Block

The harmless disposal of spent cathode carbon blocks (SCCBs) has become an urgent issue in the primary aluminum industry, and the disposal of SCCBs by co-combustion in pulverized coal boilers is expected to be the most effective treatment method. A muffle furnace at 815 °C was used in this study to perform a co-combustion experiment of meager coal and SCCBs. The ash fusion characteristics (AFTs), microscopic morphology, and minerals composition of co-combustion ash were characterized. The interaction mechanism of different mineral components and the change in AFTs and viscosity-temperature characteristics were investigated using FactSage software. Results show that the change in the ash deformation temperature (DT) is correlated linearly with the SCCB addition ratio, whereas other characteristic temperatures exhibit a nonlinear relationship. The contents of SiO2, Al2O3, and Na2O collectively determine the DT in the ash, and the influence degree from high to low is in the order of SiO2, Na2O, and Al2O3. The phase diagram of Na2O–Al2O3–SiO2 is used to accurately predict the changing trend of the melting point of co-combustion ash. The ratio changes between refractory and fusible minerals in the ash, as well as the degree of low-temperature eutectic reaction between sodium- and calcium-containing minerals, are the main factors affecting the melting point of ash. When the blending amount of SCCBs is 5%, mostly complete combustion is achieved, and slagging does not occur easily. The optimal blending ratio of SCCBs is obtained using the co-combustion method from the aspect of AFTs and viscosity-temperature characteristics. This work lays a theoretical foundation for industrial application.

Choosing of rational periodicity of engine crankcase oil changing taking into account energy-saving properties of oils

It is known that reducing friction losses and, consequently, wear is the most important function of engine crankcase oil. Many oil manufacturers add additives to the oil composition - thickening and friction modifiers. Achieving a rational periodicity of crankcase oil changing generally reduces the operating consumption of oil, the cost of which accounts for a significant share of the total cost structure of operating costs. The developed method for evaluating the energy-saving properties of the researched three grades of oil by viscosity-temperature characteristics allows for reducing the cost of conducting special research. The viscosity value's dependence on the temperature range from 20 to 100 ° is experimentally established. This work presents part of the research results to justify the choice of rational changing periodicity of diesel engines’ crankcase oil, considering the energy-saving properties of oils. During operation, it is also necessary to comply with the requirements for preserving the recommended grades of fuel and lubricants, observing their use and safety modes, and a reasonable oil level in the crankcase.

Разработка состава и технологии получения синтетического компонента основы гидравлических масел для специальной техники

The rapid development of technology, the creation of promising products with characteristics corresponding to or exceeding the characteristics of the best world analogues, dictate the need to create a new level of quality oils – synthetic. The advantages of synthetic-based oils are excellent viscosity-temperature characteristics, good low-temperature fluidity, high anticorrosive properties, as well as increased thermal-oxidative stability, compatibility with materials. Since synthetic oils are chemically stable, they retain their original characteristics longer under adverse operating conditions. Other advantages of synthetic oils include increased resistance to shear deformations (due to the uniformity of the structure), high dispersing ability, fire resistance, chemical inertia and non-toxicity. It is also important that the synthetic base requires the introduction of a minimum amount of thickening additives. In addition, their resource significantly exceeds the resource of petroleum oils of a similar purpose. Among the numerous lubricants, a special place is given to low-viscosity hydraulic oils used in autonomous hydraulic drives of special equipment. The use of a basic synthetic base makes it possible to increase the guarantees of the shelf life and operation of hydraulic oil in products and ensure a quality preservation resource for 20 years or more.

Effect of surfactant modified nano-composite flame retardant on the combustion and viscosity-temperature properties of asphalt binder and mixture

To improve the compatibility and storage stability of Nano-composite flame retardant (NCFR) in asphalt, the surface of NCFR was modified by organic coating using four kinds of surfactants. First, the effect of surfactants on the surface activity of NCFR was evaluated. Then, the mechanism of surface enhancement modification of NCFR by surfactants was analyzed. Finally, the effects of surfactant-modified NCFR on the combustion characteristics and viscosity-temperature characteristics of asphalt were investigated. The results showed that the surfactants were coated on the surface of NCFR particles through intermolecular forces and chemical bonds. The surfactant coating modification of NCFR can improve the compatibility and storage stability of NCFR with asphalt. The surfactant further improves the asphalt fire safety by improving the NCFR dispersion, and the surfactant also effectively reduces the mixing temperature of flame retardant asphalt mixture. Surface modification of NCFR using surfactants is a multifunctional method of powder modification.

Investigation of the co-processing technology of crude oil and coal and its deployment

Abstract The effect of process conditions on the co-processing technology of crude oil and coal was investigated. Crude oil/coal matching performance, swelling degree, crude oil/coal slurry viscosity-temperature characteristics and process parameters were obtained via the laboratory scale and pilot scale studies. The optimum reaction temperature of the co-processing was 445~450 oC, the pressure was 19 MPa, the catalyst addition was 3 wt.%, the reaction time was 2 h, and the ratio of hydrogen to crude oil was 1500 (V/V). Furthermore, the co-processing technology including catalyst and corresponding equipment based on the slurry bed hydrogenation were developed. By using this co-processing technology, the feed ratio of crude oil and coal can be 1:1, the coal conversion rate can be over 99%, the light oil (oil and aromatics) yield was over 70%, and the end products were gasoline, diesel, jet fuel, aromatics and LPG. The product quality meets the Euro V standard, whilst aromatics accounted for 48% of the light oil. So it was proved to be feasible to co-refine crude oil and coal at a ratio of 1:1. What’s more, the slurry bed hydrogenation plant and its equipment were tested for long-term operation, and it has been proved that this co-processing technology could be deployed as large-scale industrial application.

Design and Optimization of the Surface Texture at the Hydrostatic Bearing and the Spindle for High Precision Machining

Hydrostatic bearing spindles are widely applied in high precision grinding and turning machines due to their good dynamic stability and rotational accuracy. However, under the condition of high-speed rotations, the heat generated by the friction of the oil film will cause the shear thinning effect. It not only reduces the rotation accuracy of the spindle but also reduces the service life of the spindle. The surface texture structure and configuration between the planes play the role of homogenizing oil film temperature and preventing the bearing surface wear caused by excessive concentration of temperature, which can change the relative motion from the inside of the oil film and thus improve the performance of the hydrostatic spindle more effectively. In this paper, the influence of the surface texture shape and height on the thrust bearing performance of the hydrostatic spindle is systematically investigated by comparative analysis. The CFD simulations are developed to analyze the computational results based on the theory of viscosity-temperature characteristics. The results show that when the height of the surface structure is 1 ~ 2 times the oil film thickness, the spindle bearing performance is the best. The average temperature in the bearing region is the lowest and the accuracy of the simulations was verified by experimental results.

Progress in physicochemical properties of ash/slag from co-gasification of agroforestry waste biomass and coal

Co-gasification of agroforestry waste biomass and coal realizes energy-saving, low-carbon emission, clean and efficient raw material conversion by taking advantage of their similarities and complementarities. The physicochemical properties of ash slag for raw materials are one of the key factors affecting the stable operation of co-gasification. It is the focus of co-gasification research. This paper reviews the research status of physicochemical properties of ash slag from co-gasification of agroforestry waste biomass and coal. It mainly includes the similarity and difference between agroforestry waste biomass ash and coal ash, the fusion and viscosity-temperature characteristics of mixed ash, the effect of alkali/alkaline earth metals in mixed ash on co-gasification reactivity, and sintering behavior during the slagging process. The influence mechanism of adding agroforestry waste biomass on the melting flow and sintering behavior of mixed ash is discussed. The prediction models and methods of fusion characteristics, viscosity-temperature, and slagging characteristics of mixed ash are also summarized. Finally, the future research directions of ash slag from co-gasification of agroforestry waste biomass and coal are proposed.

Numerical simulations of droplet forming, breaking and depositing behaviors in high-viscosity paste jetting

Drop-on-demand (DOD) printing of high-viscosity pastes can solve the sputtering and low forming efficiency issues in inkjet printing technology, but the irregular deposition morphology of deposited droplets poses a challenge for the printing quality. A computational fluid dynamics (CFD) model was developed to predict the droplet forming, breaking and depositing behaviors during the high-viscosity paste jetting process. The model considers the shear-thinning and viscosity-temperature characteristics of the paste, as well as the shearing effect of needle motion during the droplet formation. The jetting process and deposition morphology were compared with the results obtained by a high-speed camera, and the predictions are consistent with the experiments. According to the CFD simulation, paste suction phenomenon appears when the needle moves upward, and part of the paste flows back into the reservoir when the needle moves downward. In addition, the effects of the input parameters (operating pressure, spring preload angle and fluid pressure) on the droplet volume, deposition diameter and bump height of the deposited paste were revealed. This study provides an in-depth and clear understanding of the high-viscosity droplet formation and also lays the foundation for the morphological control of conductive lines in high-viscosity paste DOD printing.

Crystallization and viscosity-temperature characteristics during co-gasification of industrial sludge and coal

Crystallization and viscosity-temperature characteristics during co-gasification of industrial sludge and coal

Toughening of benzoxazine structural adhesives and surface films

In this paper, acrylic triblock copolymer (BMG) was used to toughen the benzoxazine/epoxy (BZ/EP) resin system and prepare a BZ/EP/DDS/BMG resin. BZ/EP/DDS/BMG resin curing characteristics, viscosity-temperature characteristics, heat resistance, toughness, morphology, and bonding performance were studied. The results show that the curing agent 4,4-diamino diphenyl sulfone (DDS) can lower the curing temperature of the BZ/EP/DDS system, making it suitable for co-curing of benzoxazine prepreg. The BMG did not affect the curing temperature of the BZ/EP resin. When 15 phr BMG was added, the viscosity of the BZ/EP/BMG resin at 139–189 °C was lower than 5.0 Pa·s, showing a minimum viscosity of 2.0 Pa·s. BMG significantly increased the toughness of the BZ/EP/DDS/BMG system while barely decreasing its heat resistance. The impact strength of the BZ/EP/BMG resin increased by 71% when 20% BMG was added. Furthermore, theBZ/EP/DDS/BMG resin demonstrated excellent bonding performance, with lap shear strength and peel strength at room temperature reaching 30.6 MPa, and 37.2 N/cm, respectively. Therefore, the prepared BZ/EP/DDS/BMG resin is suitable as a matrix for BZ structural adhesives and composite surface films.

Design of a Hydrostatic Spindle and Its Simulation Analysis with the Application to a High Precision Internal Grinding Machine

Hydrostatic thrust bearings are the core part of the hydrostatic spindle, which is widely used in high precision grinding machines. In this paper, the viscosity-temperature (v-t) characteristics of hydrostatic oil are systematically investigated, which is essential for improving the performance of the hydrostatic thrust bearing and the spindle working at high pressure and high rotational speed. Based on the computational fluid dynamics (CFD) simulation developed, the performance variation rules of thrust bearing surface are established while changing the oil supply pressure. It is found that the bearing capacity and temperature are obviously affected by varying viscosity-temperature characteristics, which have significant fluctuation phenomenon at the orifice. Furthermore, the turbulence intensity of the taper hole is found the least factor by analyzing four kinds of commonly used orifice type configurations. Finally, comparing the simulation and experimental results, the v-t model developed is proofed well matching with the experiment. The model can provide a basis for accurate design and analysis of hydrostatic thrust bearings and consequently the effective design and analysis of the hydrostatic spindle for high precision grinding machine.

Effect of components on the emulsification characteristic of glucose solution emulsified heavy fuel oil

Glucose, which can be obtained from the biomass directly, was added into the heavy fuel oil in the form of an aqueous solution to prepare a novel alternative emulsified fuel. The effects of different components (water, glucose and surfactant) on the droplet size distribution, the stability and the viscosity-temperature characteristics were studied experimentally. Results show that the increases in both the water concentration (0–40v/v%) and the hydrophile-lipophile balance (HLB) value (4.3–14.3) have the negative influence on the stability. By contrast, with the enhanced glucose blend ratio (0–40%), the stability and the homogeneity present the rising trends before they are decreased. It is worth noting that the long-term stability (85 °C, 30 days without separation) along with the minimum mean droplet size can be obtained at the 30% glucose blend ratio. Besides, the long-term stability cannot be not obtained at both surfactant concentration of 1% and 5%. The viscosity of the emulsion with surfactant is reduced in the range of 25–35 °C but increased in the range of 60–95 °C compared with that of emulsion without surfactant. Furthermore, there exists the quite slight change of the viscosity with the addition of glucose.

Determining criterion of the operating temperature in the refractory brick entrained-flow gasifier based on the coal viscosity characteristics and slag flow process

Entrained flow gasification technology is currently widely used in the coal chemical industry. However, the selection of candidate coal for achieving smooth slag discharge is significantly limited. Herein, the temperature distribution in the slag tapping hole of the refractory brick lining gasifier was analyzed. The effect of the slag viscosity-temperature characteristics on slag discharge behaviors was evaluated. Specific theoretical criteria rather than empirical estimation were proposed for selecting the operating temperature and candidate coal, which were important for industrial production. The results showed that the temperature in a localized area of the slag tapping hole was very low in current refractory-scheme, which induced the formation of solid-slag. The slag viscosity-temperature characteristics were found to be the key factors influencing the slag discharge process. Moreover, the operating parameters including the ‘sensitive characteristic temperature’ and ‘no-solid slag characteristic temperature’ were proposed, in which the temperature range was optimal for different slags.