Papers by Keyword: Desulphurization

Abstract: High amount of basic oxygen furnace (BOF) slag in steelmaking process is a big challenge, therefore, recycling of the slag have been extensively concerned by not only steelmakers but also researchers. One of the promising methods is to use the slag as a flux in the pretreatment process because the basicity of slag is high and it contains high amount of MgO and CaO. This study examines recycling ability of the BOF slag as a part of the flux adding to the pretreatment process. In the experiment procedure, the flux was combination of the slag (59 mass%), CaO (32 mass%) and SiO₂ (9 mass%). The flux and the iron sample were put into the crucible, and then set up in the resistance furnace. The experiments were carried out at different temperatures of 1450, 1500 and 1550 °C with holding time of 15 minutes. The results shown that the S content in the iron significantly decreased in all cases of temperatures. S content in the iron in the pretreatment process reduced from the initial value to 0.007 mass% at the temperature of 1450 °C. However, at temperature of 1550 °C, the S content in the iron was 0.012 mass%. Besides, Si content in the iron reduced with increasing temperature; Si content in the iron significantly decreased from initial value of 2.67 mass% to 0.05 and 0.06 mass% once the temperatures were 1500 and 1550 °C, respectively. Additionally, it was indicated that Fe content in the slag after reaction dropped from the initial value of 6.20 mass% to 0.62 mass% at the temperature of 1550 °C.

Abstract: In petroleum industry, hydrodesulphurization (HDS) process is considered as one of the crucial catalytic units in which the sulfur is mostly eradicated. The modeling of HDS process is very important for the proper understanding of the process operation to be optimized. The studies conducted, in this area, focused on predicting parameters using analytical, empirical and numerical approaches. However, a typical desulfurization process is constantly faced with an uncertainty, which should be considered in a reasoning way. Therefore, this work aims to explore the use of fuzzy logic (FL) inference system in creating models of the HDS process for the prediction of sulfur reduction from oil. In order to validate the proposed model, we employed experimental data from the HDS setup. The simulated sulfur content results obtained from the proposed model correspond closely to the real experimental values. The outstanding performance of the developed FL-based model suggests its potential in predicting sulfur content for optimization of the HDS process. The model demonstrates promising results in terms of high correlation (R²=0.98) and minimal percentage of error (AARE=0.072).

Abstract: The large cost of the flotation reagents used in the first-of a two-stage desulphurization flotation process, developed for the treatment of South African waste coal ultrafine tailings, has motivated the investigation of Mycobacterium phlei as an alternative coal bioflotation reagent. Attachment experiments were used to confirm that the microbe attaches to South African coal selectively over pyrite or gangue material present in the coal. Subsequent small scale batch floats using M. phlei successfully showed that the bioflotation process can upgrade and desulphurize the coal tailings feed, and delivered approximately the same concentrate yields as the optimised chemical flotation conditions (37 – 39%). However, a projected financial feasibility analysis that assessed the incorporation of the M. phlei into the two-stage flotation process found that the bioflotation process was not profitable due to the very large flow rate of cells required (2×10¹⁶ cells/ton coal) and the associated additional equipment and growth media component costs.

Abstract: The desulphurization process parameters of vanadium bearing hot metal were optimized. It is found that it has the best desulfurization effect in 100t hot metal ladle, when the lance position is 280mm, the ratio of lime to Mg is 3:1, and the Mg injection rate is 9kg/min. The Si and Ti content of hot metal can increase the activity of S. With the increase of Si and Ti content of hot metal, the final sulfur content has a reduction trend. When the content of Si and Ti is lower than 0.35%, the final sulfur content of hot metal increases, and the hit rate decreases. The effect of hot metal temperature on desulfurization end point hit rate is obvious. When the hot metal temperature is between 1300~1320°C, the hit rate of desulfurization end point is higher. When the temperature is below 1300°C or above 1320°C, the sulfur content increases. After optimization of process parameters, the Mg and lime consumption per ton of hot iron are reduced by 0.11kg and 0.54kg, respectively, with the average hit rate of desulfurization end point increased by 22.6% and 10.7%, respectively.

Abstract: Synthesis of a novel class of cyclic sulphonium based ionic liquids was performed. The ionic liquids were characterized using ¹H NMR spectroscopy, FTIR spectroscopy and CHNS elemental analysis. The physicochemical properties of the ionic liquids such as density viscosity and thermal decomposition temperature of the synthesized ionic liquids were determined. The potential of these ionic liquids for the extractive desulphurization of model oil was investigated.

Abstract: The mainly pollutant from coal-fired power plants are SO₂ and NO_X. Equipments of desulphurization and denitrification step by step are expensive and have a lower efficiency. Comparing with them, Combined Removal of SO₂ and NO_X technology have great advantages, such as, the simplified complication, better operation property, lower cost and less using area. So Combined Removal of SO₂ and NO_X in one system become the keystone in the research of cleaning technology .On the base of looking up a lot of references, this paper makes a detailed introduction about Combined Removal of SO₂ and NO_X technology lately in China and other countries, including the removal principle, the mainly advantages and defects, the present situation and the application of technology. The contrast of economic and technical standard is given .Through analysis, synthesis and comparison of two kinds of technology-Combined Removal of SO₂/NO_X in boiler and in flue gas, the key of research in future is found out. These contents can reference in improvement and exploiture of technology later.

Abstract: Compared with a great deal of traditional desulphurization crafts, the catalytic reduction of SO₂ with CO to elemental sulfur is considered to be the best technology for the removal of SO₂ from flue gas. Adding rare earth oxide CeO2 with variable valences to La₂O₃ formed a mixture of rare earth oxides. By means of dipping CeO₂, La₂O₃ and their mixture, whose carriers are allγ-Al₂O₃, are used as the catalyst for the reduction of SO₂ by CO. The activation process of this catalyst without O₂ was investigated. The result shows that the rare earth oxide mixture composing of CeO₂ and La₂O₃, as the catalyst for the reduction of SO₂ by CO, can remove SO₂ mostly without O₂.

Abstract: The significance of desulphurization and denitrification is more obvious in removal SO₂ and NO_x from flue gas emission during coal combustion. This paper summarized the latest progress of desulphurization and denitrification on wet, semi-dry, dry and microbiological purification, simultaneously. It is pointed out that the development and application prospects of simultaneous desulphurization and denitrification treatment have favorable.