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During the combustion of straw, the formation of deposition, which destines to furnace erosion and exerts great influence on safety operation, on heating surface is affected by many factors. The paper studies the influence of speed and amount of air. According to the test: the air speed affects the sedimentary quantity of fly ash and the deposition position; the air amount affects the fuel combustion...
The characteristics of the reaction between nano aluminum and water at low temperature were studied. The effects of temperature and additive on reaction rate were derived. The results indicate that the reaction rate of nano aluminum/water increases with the increase of temperature. Moreover, the reaction rate of nano-aluminum/water is enhanced by polyacrylamide. The reaction mechanism of nano-aluminum/water...
In this paper, the experimental study on the NOx emission characteristics of co-combustion of pulverized coal and waste tyre has been conducted by a tube furnace. Four fuels with different ratio of waste tyre and coal were tested. It was found that when the ratio changes, the NOx emission process shows similarly, but the NOx emission rate and total value are different. The fuel N exhalation rate changes...
Heat release analysis in diesel engines is a powerful method to investigate the combustion process and engine performance. The aim of this study is to simulate the heat release rate during combustion using the measured in-cylinder pressure based on thermodynamic principles. After determining the submodels such as mass and composition, gas and fuel properties, heat of combustion, heat loss to the walls,...
This paper designed and described a Helmholtz-type valveless self-excited pulse combustor with continuous fuel and air supply. Its structure is similar to the conventional Helmholtz type's, but valves are not used. The operational characteristics of the Helmholtz-type valveless self-excited pulse combustor was investigated by the experiment. The effects of the excess air ratio, tailpipe length and...
In this paper, two typical Chinese coals were selected to investigate the pulverized coal combustion characteristic and their pore structure evolution in oxy-fuel combustion and conventional air combustion environment with a drop tube furnace (DTF). Results show that the burn-off rate of pulverized coal in O2/CO2 mixtures is lower than that in O2/N2 environment with equivalent oxygen concentration...
In this paper, a simulation model was built for in cylinder stratified charged and lean combustion GDI engine, and the spray model was validated. Based on this, numerical simulation of mixture stratified combustion was performed in a gasoline direct injection (GDI) engine with AVL FIRE. The effects of different injection timings on the mixture quality near the spark plug were analyzed and the results...
The reaction of a Chinese bituminous coal PDS with Fe2O3 was investigated by such experimental means as thermogravimetric (TGA) coupled with Fourier transform infrared spectroscopy (FTIR) and TGA-difference thermal analysis (DTA) with focus on the effect of the heating rate. It was found that the reaction of PDS with Fe2O3 displayed three-staged reaction characteristics, and a higher heating rate...
Through the research of the pulverized coal ignition and steadily combustion mechanism and the numerical Simulation of the 300MW tangentially pulverized coal fired boiler by coalfire software, combining the operating data of the boiler, we establish the corresponding relation between the result of numerical simulation and combustion stability. The result indicates that the higher volatile, lower content...
Due to the current qualitative method of the unburned carbon in fly ash for tangentially pulverized coal-fired boiler, the factor analysis was applied creatively to estimate quantitatively every influence on the unburned carbon in fly ash, considering the actual operations of 300MWe boiler. This study established the factor model to analysis the influences of unburned carbon in fly ash, and listed...
Micronized coal reburning is one of the most effective de-NOX technologies for its high NOX reduction efficiency and low operating cost. By numerical simulation and experimental study, NOX reduction efficiency influenced by the temperature and stoichiometric ratio in rich zone, the velocity and the particle size of reburning fuel during the coal reburning process in a one dimension furnace has been...
Numerical simulation on combustion flow field of one gas turbine combustor which burning C12H23 was studied in the paper. What did we adopt in the paper is PDF fast chemical reaction model, SIMPLEC algorithm, Pressure-swirl atomizer and DPM random walk track model. This paper analyzed the difference between cold and combustion flow field, and the flow field performance under different turbulent models...
With a thermo gravimetric analysis apparatus combustion characteristics experiments of sawdust, corn straw and mixtures of them were done at 10,20,40°C/min heating rate. The combustion activation energy was acquired by kinetics analysis. The experiment results show that the ignition characteristic and synthesis combustion of corn straw are better than sawdust. The mixture of corn straw and sawdust...
China enjoys rich lignite resources. However, the development and utilization level of lignite in China is low compared with other countries. The lignite in China is distributed mainly in the eastern areas of Inner Mongolia and in the northeast provinces. The characteristics of China's lignite are closely related to its coal-forming age. Due to the shallow buried coal seams, most parts of the lignite...
This work presents some experimental research on the penetration of secondary air injection in a cold circulating fluidized bed (CFB) which has a square cross-section of 0.25m × 0.25m and a height of 6.07m. Using CO2 as secondary air injection tracer, a simple model was developed to predict the penetration depth of secondary air in the CFB. Based on the fundamental momentum ratios of cross flows,...
The pulverized coal combustion in O2/CO2 atmosphere is one of the promising new technologies which can reduce the emission of carbon dioxide and NOx. In this study, a three dimensional mathematical multiphase CFD model has been developed to simulate the combustion characteristics of pulverized coal in the atmospheres of O2/CO2. It was observed that the combustion characters of pulverized coal show...
Characteristics on temperature profiles of no premixed combustion in porous media were investigated experimentally. Ignition start-up process and stability were discussed at the certain operating parameters. Influences of fuel-air ratio on the temperature profiles were analyzed in details, in addition to the velocity. The results showed that stable start-up can be obtained at the certain operating...
Experimental study was carried on a 300MW swirling combustion pulverized coal firing furnace with put parts of tertiary air as over fire air to reduce NOx emission. The influence of boiler operational condition on the characteristics of NOx emission were studied, such as the content of O2 at economizer exit, the proportion of the top tertiary air and mass flow of over fired air (OFA). Results show...
Staged combustion technology is adopted in the trapped vortex combustor, a pilot combustor is used for flame stability and a main combustor is used for power. Low emissions combustion can be achieved by controlling mixing of oil and gas in pilot combustor and main combustor. Experimental research has been conducted to investigate the emissions of pilot stage of double vortex combustor. The combustor...
The reaction of a Chinese coal PDS with Fe2O3 was investigated using thermogravimetric (TGA)-difference thermal analysis (DTA), with focuses on the effect from such four factors as atmosphere, oxygen excess number Φ, the reduced valence of Fe2O3 and the inert support Al2O3. It was found that CO2 atmosphere facilitated the reaction of Fe2O3 with PDS, especially at the final stage, the exothermic reaction...
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