Sulphur removal in ironmaking and oxygen steelmaking

Sulphur removal in the ironmaking and oxygen steelmaking process is reviewed. A sulphur balance is made for the steelmaking process of Tata Steel IJmuiden, the Netherlands. There are four stages where sulphur can be removed: in the blast furnace (BF), during hot metal (HM) pretreatment, in the converter and during the secondary metallurgy (SM) treatment. For sulphur removal a low oxygen activity and a basic slag are required. In the BF typically 90% of the sulphur is removed; still, the HM contains about 0.03% of sulphur. Different HM desulphurisation processes are used worldwide. With co-injection or the Kanbara reactor, sulphur concentrations below 0.001% are reached. Basic slag helps desulphurisation in the converter. However, sulphur increase is not uncommon in the converter due to high oxygen activity and sulphur input via scrap and additions. For low sulphur concentrations SM desulphurisation, with a decreased oxygen activity and a basic slag, is always required.     

三明钢铁公司单吹颗粒镁铁水脱硫工艺实践

简述了三明钢铁公司炼钢厂单吹颗粒镁铁水脱硫的工艺装备特点,分析了热调试运行取得的脱硫效果,并针对影响铁水脱硫率、颗粒镁的利用率等相关因素进行了分析.测算了处理铁水温降、铁损和脱硫成本,并提出了铁水脱硫站目前存在的主要问题及其解决措施.     

湘钢铁水脱硫首期工程设计及投产

湘钢二炼钢厂铁水预处理脱硫与扒渣系统首期工程已经建成。文中简述了该项目建设概况,并小结了试车、投产期的初步效果.     

A comparative study of mathematical models for gas-solid non-catalytic reactions

Experimental data on desulphurisation of a simulated coal gas mixture containing 200 ppm H₂S, using CuO/ZnO mixed oxide sorbent in a fluidised bed reactor, are used to evaluate four representative structural models for gas-solid non-catalytic reactions. The four models chosen for evaluation are the spherical changing-grain-size model of Georgakis and co-workers, the rectangular grains version of the general formulation of Szekely and co-workers, the single-pore model of Ramachandran and Smith and the random pore model of Bhatia and Perlmutter. All the model parameters except the reaction rate constant are calculated from experimental measurements or from literature correlations. The rate constant alone is adjusted so as to obtain good agreement between the model and the experiment. It is shown that at any given temperature all the models describe the data well. However, the random pore model predicts conversions lower than experiment at large times while the rectangular grains model predicts conversions higher than experiment for small times. The rate constants decrease as temperature increases indicating an inadequacy of all the models in this regard. The models also predict much smaller variations in conversion with change in particle size than those observed experimentally.     

The catalytic reduction of SO2 by CO over lanthanum oxysulphide

Lanthanum oxysulphide was found to be an effective catalyst for the reduction of SO₂ by CO to elemental sulphur. Over 98% in SO₂ conversion and selectivity to elemental sulphur can be achieved under the following conditions: temperature above 500°C, stoichiometric CO/SO₂ feed ratio, and a space velocity 21,600 cc g⁻¹ h⁻¹. COS in the low ppm level was detected as a by-product similar to our earlier work with perovskite. The catalyst is resistant to oxygen and water vapour. In addition, it was recognised that the lanthanum oxysulphide is bifunctional, i.e., not only is it active in the reduction of SO₂ by COS [J.A. Baglio, Ind. Eng. Chem., Prod. Res. Dev., 21 (1982) 38], but also its lattice sulphur atoms are mobile enough to form COS with CO. This suggests that lanthanum oxysulphide functions as a catalyst for the reduction of SO₂ by CO via the intermediate COS.     

热电厂扩建工程脱硫工艺选择的初步探讨

简要介绍了循环流化床脱硫技术和几种烟气脱硫技术工艺的特点,结合电厂扩建工程的实际情况,对循环流化床锅炉脱硫和煤粉炉加半干法烟气脱硫技术方案进行了技术经济比较,对脱硫技术方案的选择给出了建议。     

分子印迹水凝胶固相萃取石油有机硫组分

以壳聚糖为功能单体,制备苯并噻吩类硫组分分子印迹固相萃取剂,系统地研究了其分子识别机理,根据目标分子的结构理性地选择了交联剂、致孔剂和聚合方法,探索了不同制备条件对模板聚合物特异性识别能力的影响;总结了影响印迹聚合物识别能力的一般规律,试验结果显示,以环氧氯丙烷为交联剂制备得到的印迹材料对二苯并噻吩的吸附容量达到17.53 mg/g。     

VANTAGE PDMS工厂设计信息技术系统在脱硫工程中的应用

VANTAGE PDMS(Plant Design Management System)是面向数据的大型三维工厂设计集成应用系统。它提供了一体化多专业集成布置设计数据库平台。缩短了设计周期,社会效益显著。     

Full-scale measurements of SO2 gas phase concentrations and slurry compositions in a wet flue gas desulphurisation spray absorber

Two measurement campaigns were carried out at ENERGI E2's Asnæs Power plant, unit 5. The unit has a capacity of 620 MW_e and is equipped with a wet flue gas desulphurisation (FGD) plant employing a counter-current spray absorber with five spray levels. In the first campaign, the power plant was firing Orimulsion^® with 2.85 wt% S resulting in a flue gas concentration of SO₂ exceeding 2000 ppmv. In the second campaign, the fuel applied was a low-S blended coal and the SO₂ concentration in the raw gas was around 400 ppmv. A novel probe for in situ sampling of gas phase concentrations in wet FGD spray absorbers was developed and applied for measuring axial profiles of the SO₂ gas phase concentrations in the absorber. The expected decrease in SO₂ concentrations along the height of the absorber was found in the spray section (from height 26.5 to 36.2 m) whereas the SO₂ concentration above the holding tank and below the gas inlet was quite low probably due to long local residence times in the region. Horizontal variations, due to somewhat different flow conditions near the column wall were investigated and the SO₂ concentrations were found to be higher near the wall. Measurements at different gross loads showed that the SO₂ gas phase concentration at a given position inside the absorber was roughly linearly related to the L/G ratio in the measuring interval. Turning off one of the lower spray levels, while burning coal with low S content, did not lower the overall removal efficiency of the absorber. However, the SO₂ gas phase concentration inside the lower part of the absorber was increased by a factor of 2-3. Measurements of slurry pH at different positions showed a decrease of approximately 0.5 units from the upper to the lower part of the absorber. The full-scale measurements provide a detailed set of experimental data for validation of mathematical models of a wet FGD spray absorber.     

From waste to wealth: recycling the secondary resource from steel ladle as a flux in Si-killed steelmaking process

With the regulations pertaining to the environment and waste disposal becoming stringent day by day, the steelmaking industry is being compelled to adopt a zero-waste-policy for sustainability. As a consequence, 3R (reduce, reuse and recycle) technique of waste handling has become the most favoured option among the industries. This paper focuses on recycling of slag generated after secondary refining process. Trials were conducted in two stages, namely (a) prevention of dusting phenomenon of Al-killed steel ladle slag to generate lump slag by suitably selecting the ladle covering compound and chemically modifying the slag, and (b) utilisation of the lump slag as a 100% replacement of synthetic slag in Si-killed steel ladles, leading to a reduction in its specific consumption from 1.2?kg/TLS to zero. As a process requirement, specific power consumption, arcing time and degree of desulphurisation were considered as the major parameters for comparing the results using hypothesis test statistical tool.