Advanced Materials Research Vols. 347-353

Abstract: The thermal analysis has been employed to yield information on the biodiesel ignition quality since the ignition quality influences the combustion and exhaust emissions of the fuels in a compression ignition (CI) engine. The chemical compositions of -10 petrodiesel (-10PD), soybean-based biodiesel (SME) and cottonseed-based biodiesel (CME) are analyzed by gas chromatography-mass spectrometry (GC-MS). Ignition temperature of -10PD, SME and CME is determined by thermogravimetry-differential scanning calorimetry (TG-DSC). The study shows that the biodiesel is mainly composed of fatty acid methyl esters: C14:0–C24:0, C16:1–C22:1, C18:2 and C18:3. Biodiesel ignition quality is better than petrodiesel. The ignition temperature of CME and SME is 207.4 and 213.9 °C respectively. The ignition quality of biodiesel is better with shorter carbon chain lengths and more saturated fatty acid methyl ester (SFAME).

Abstract: Thermogravimetry (TG) has been employed to yield information on the thermal volatilization of the fuels since the volatility influences the ignition quality of the fuels in a compression ignition engine. The chemical composition of -10 petrodiesel (-10PD) and waste oil biodiesel (WME) was analyzed by gas chromatography-mass spectrometry. The thermal volatilization of biodiesel and its blends was investigated by TG and liquid volatile theory. Volatile index was put forward for describing biodiesel/petrodisel volatility. A good correlation model was proposed for calculate the biodiesel/petrodiesel volatility by biodiesel blending ratio. The study showed that -10PD and WME had similar chemical composition and structure. -10PD was mainly composed of long chain alkanes: C8–C26. WME was mainly composed of long chain fatty acid methyl esters: C14:0–C22:0, C16:1–C22:1, C18:2 and C18:3. The volatile indexes of WME and -10PD were 1.47E-04 and 3.64E-05, respectively. The biodiesel was considerably more volatile in comparison to the petrodiesel. The WME/-10PD volatility was better with increasing the biodiesel blending ratio.

Abstract: The combustion mechanism of bio-oil derived from wood fast pyrolysis was investigated by thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TG–FTIR) in flowing air. The results show that the combustion process of bio-oil consists of two main consecutive stages at a low heating rate. The combustion reaction becomes more and more intense from the first to the second stage. The release of volatiles occurs mainly at 80～200 °C and 350～500°C, and the gaseous products in each stage are different. The main products in the first stage are H₂O with a few low molecule weight compounds, such as methanol, formic acid, etc. In the second stage, some new volatiles such as CO₂, CO and CH₄, etc. are present. Among the above volatiles, CO₂ is the dominant gaseous product in the whole combustion process. The concentrations of CO₂ and CO keep increasing, and reach the maximum at about 450 °C. Over 570°C, there are few products released at the end of the combustion process.

Abstract: Because of its high output，much more dust is produced in fully-mechanized Longwall mining with top-coal caving (LMTC) mining faces than in conventional mechanized mining faces without top-coal caving. Now dust control in fully-mechanized LMTC mining faces has become a key technological problem needed to be solved. Baced on the ejected dust removal technology, this paper developed a coal dust extraction which used in the fully mechanized LMTC mining face. For the optimization of the extraction’s property, measure systems are designed. By amounts of assembled experiment, the best structure of the extraction is found. In this paper, the research of the spray characteristic on the water nozzle was carried out by using the jet parameter testing system. Some important result can be gotten such as the velocity of spray particle, the distribution of the velocity, the diameter of spray particle, the spread of the spray particle etc. The study was helpful to optimizing the exhausting-flowing remover and improving the dust remover’s efficiency. From the industry examination, the coal dust extraction’s performance has greatly improved.

Abstract: Biomass is an important renewable and sustainable source of energy. Cellulose is the primary component of plant-derived biomass. Glucose, which can be further transformed to fuel alcohol in a fermentation process, is a biomass energy precursor. This study investigated the production of glucose from cellulose by hydrolysis in sub-critical water and the hydrolysis kinetics of cellulose. Kinetics was conducted in a temperature range of 240-260°C using a 200 ml stainless steel batch reactor. A simplified kinetic model base on parallel and consecutive reaction was proposed. The differential equations resulting from the model were fit to experimental data to obtain kinetic rate constants. The activation energy and the pre-exponential factor were determined. A good agreement between the simplified model and the experimental data was obtained. The experimental results show that the best hydrolysis technology is: reaction temperature 260°C, reaction time 120s. Under this condition, the glucose yield reaches 46.05%.

Abstract: The purpose of this paper is to find a method to study the lubrication character of the main bearings and load condition of the crankshaft about the marine two-stroke diesel engine. Based on the finite element method, multi-body dynamics, elastohydrodynamic and Green-Tripp theory about contact, the simulation of coupling between the elastic crankshaft and engine block is carried out. The load of main bearings, the minimum of oil film thick, orbital path of journal, average of asperity contact pressure are explored. The results indicate that the lubrication is good except No.2 main bearing. Parts of main bearings appear three peaks in a working cycle, which shows that above theory and elastic crankshaft and engine block is obligatory to simulate the lubrication and load condition accurately.

Abstract: This paper studied the co-pyrolysis behavior of crop straw and swill-cooked dirty oil (≈ 2:1 ratio by weight) at 10, 30, 50K/min, in dynamic thermal gravimetric analyzer (TGA) under inert atmosphere, from 303K to 973K. The kinetic parameters were calculated using the method of Ozawa-Flynn-Wall, and mechanism was hypothesized as first-order model. The results showed that the dirty oil led degradation temperatures to slide towards higher slightly, meanwhile broadened the temperature interval of decomposition. However, the presence of dirty oil had little impact on activation energy. These findings indicated a significant synergistic relationship between straw and dirty oil, and it was practicable for co-pyrolysis from the viewpoint of thermal and kinetics analysis.

Abstract: The measurements of oil properties of crude Jatropha oil and its blends of 10%, 20%, 30%, 40%, and 50% with diesel fuel have been carried out in this study. Our results suggested that the viscosities of crude Jatropha oil (CJO) blends decrease gradually with increasing temperatures, but they increase gradually with rising ratio of crude Jatropha oil compared to those of diesel fuel. Analysis of physical properties suggested that cold filter plugging point, calorific value, gravity and cetane index decrease gradually with rising percentages of crude Jatropha oil, but the flash point and mid boiling point increase gradually compared to those of diesel fuel. In this study, the prepared oil blends are applied to a power generator for a real application test. Results of electricity generation suggested that crude Jatropha oil blends may be used as an alternative fuel compared to that of diesel fuel. Results of gas emissions in a power generator suggested that CO, CO₂ and NO_X emissions from crude Jatropha oil blends are lower, but O₂ emissions are higher compared to those of diese fuels.

Abstract: Supercritical heat transfer correlations are obtained under the certain experimental conditions.The experimental parameters and its application scope is different under different experimental conditions, such as pressure, mass flow density, heat flux, tube diameter, temperature and so on. Supercritical heat transfer correlations are generally chosen in line with the correlation experimental conditions. However, some parameters are calculated under some conditions, under which we can not achieve good results, and at the same time it is prone to increase the deviation. We can choose the best experimental correlation of different experimental conditions based on the fuzzy nearness principles. The existent similarity degree mathematical model is limitated when calculating some similarity parameters.Using new mathematical calculation model resolves this problem, and we can get better experimental correlation for different supercritical heat transfer conditions with the relational selection.

Abstract: Utilized the reducing sugar amount and cumulative hydrogen production that produced by the enzymolysis of the biomass crushed by the ball mill as reference, the experiments on the relationship between different sort of raw material and different reducing sugar yield show that the corncob reducing sugar yield and cumulative hydrogen production uptake after enzymolysis is highest, reaching 1088mL.Observed the microstructure of the crushing cornstalk and corncob with canning electron microscope and X-ray diffraction, the analysis results showed that: after ball mill crushing, biomass cell wall was effectively opened, specific surface increased, particle size decreased, the microstructure changed and became loose and porous, the cellulose degree of crystallinity were all aggressively lowered, cellulase accessibility increased, the biomass degrees of saccharifying rate improved, made the hydrogen producing capacity increased efficiency.