•Comparison between CFD predictions and in-flame measurements of 3MW oxy-NG tests.•Modeling strategies required to diminish the computational time.•Inadequacy of fast chemistry approaches to treat ...the turbulence/chemistry interaction.•Strong influence of the spectral model on predictions.
The modeling through computational fluid dynamics of oxy-natural-gas combustion experimental tests in a 3MW semi-industrial furnace equipped with a low NOx burner is discussed. Since the complex geometry of the burner and the size of the furnace, a modeling strategy has been adopted to diminish the computational time and thus to make the simulations affordable. The model aims at validating different sub-models (e.g. combustion/kinetics, radiation/spectral) for oxy-natural-gas fired conditions through the comparison of predictions and in-flame measurements of temperature and chemical species. It is found that fast chemistry approaches are unable to predict the temperature field. The spectral model was also found to play a fundamental role for the correct analysis of such scale devices. Uncertainties in experimental and modeling results are discussed and compared.
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•The co-gasification characteristics of coffee shell and low rank coal are studied by RMS for the first time.•An effective influence mechanism was evaluated by combining ...dynamics.•Coffee shell can be used as a tempering agent in industrial silicon smelting.•Coffee shells are an attractive feedstock for the production of biomass carbon.
Coffee shell (CS), a type of waste stripped off during the coffee production process, possesses practical significance and economic value. First, CS was examined to explore its synergistic strengthening effect when combined with unbonded coal (NC). The evaluation encompassed aspects of thermodynamiCS, gasification reactivity, and kinetiCS. As the CS proportion in the mixed carbon material increased from 10 % to 50 %, the gasification reactivity (R) increased from 1.203 to 2.427.Activation energy in the cracking phase Ea decreased from 146 to 87 kJ/mol (a decrease of 40 %), and the order of magnitude of A0 gradually decreased. This is attributed to the adsorption of alkali metal in CS onto NC, which reduced the activation energy required for fixed carbon cracking and involved kinetic compensation. The H released by the sharp reduction of hydrogen bond and methylene content in CS is mainly absorbed by NC in the form of methane, which promoted pyrolysis and gasification. Finally, a semi-industrial test in which CS was applied to industrial silicon smelting was conducted. The results show that the application of CS increases silicon production by 3.2 %, reduces carbon consumption by 6 %, and reduces energy consumption by 2.5 %. In silicon production, CS can effectively replace some carbon-containing materials as reducing agents, which can reduce carbon emissions and save energy. This approach also supports the industrial silicon industry’s shift from energy consumption control to carbon emission control, thereby yielding substantial economic value and social benefits.
The effective utilization and clean recycling of tailings are important to solve land occupation and waste mine pollution problems. A semi-industry experiment of hydrogen-based mineral phase ...transformation for tailings is conducted with a roasting temperature of 500 °C, a reducing gas concentration of 20 %, a total gas volume of 12 m3/h, and a handing capacity of 100 kg/h. A concentrate product with an iron grade of 66.75 % and a recovery of 82.79 % was obtained. The detail roasted iron phases of 23.96 % Fe3O4 (A) and 47.93 % Fe3O4 (B) were obtained. The maximum saturation magnetization increased from 6.69 to 18.96 A·m2·kg−1 after roasting. The surface of Fe3O4 occurred on the iron mineral surface. The SEM-EDS results showed the order of reduce behavior. In addition, the pollutions of the roasting process were controlled strictly, and the final benefit was calculated to be $33.86 million.
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As a waste ferromanganese ore resource, unavailable due to conventional technology and thus hoarded in mass quantity, in which it functions as an invaluable recycling value. In the study, an ...efficient semi-industrial test for recycling manganese and iron was investigated by suspension magnetization roasting, and with the results demonstrating that iron concentrate with an average iron grade of 66.60% and an average iron recovery of 93.93%, manganese concentrate with an average manganese grade 46.22% and an average manganese recovery 87.29% could be obtained under conditions of roasting temperature 500 °C, reducing agent concentration 45%, reducing agent dosage 12.0 m3/h and the equipment operating continuously and stably for 35 h. Through the suspension magnetization roasting-magnetic separation technology, the weak magnetic hematite, pyrolusite and bixbyite were selectively converted into magnetite and manganosite respectively, and then the magnetite and manganosite were extracted in the magnetic concentrate and magnetic tailings individually. Suspension magnetization roasting semi-industrial system exhibited stable and efficient performances for the recycling and utilization of ferromanganese ore.
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•Reuse of waste ferromanganese ore as a valuable resource.•Advanced suspension magnetization roasting (SMR) technology was proposed.•Perform a semi-industrial test for value minerals recycling.•High-quality iron concentrate and manganese concentrate were obtained.
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