Hydrotreating data interpretation by chemometrics

Hydrotreating in the presence of dispersed catalysts has been considered a promising route to obtain valuable fuels from heavy hydrocarbon cuts. A laboratory-scale study on the effect of operating conditions on heavy feedstock hydrotreating performances is reported. In order to maximise the effectiveness of the research activity, chemometrics was exploited both for experimental design and data interpretation.     

燃煤锅炉高温喷射脱硫剂对烟尘的影响

燃煤锅炉喷射吸收剂脱硫是对ＳＯ２有中等控制程度的有效方法，该法比采用烟气脱硫（ＦＧＤ）技术的费用低，较适用于对ＳＯ２控制要求不太严格的国家和地区．但由于吸收剂的喷入，也引起烟尘性质的变化，给后部除尘设备的选用带来一些影响．本文探讨这些影响和寻求解决办法．     

Flue-gas desulphurisation products from Polish coal-fired power-plants

Many desulphurisation installations were constructed in the Polish power industry in recent years, so SO₂ emissions were reduced by a half to 1.04×10⁶ tonnes in 2000, while SO₂ capture increased to 43.7% in 2000. FGD gypsum, obtained by the most important wet-limestone desulphurisation method, is recognised as a substitute for natural gypsum. Its production in Poland started in 1994, and amounted to 1.1×10⁶ tonnes in 2000. It is currently fully used in gypsum binders, plasters and plasterboard manufacture, as well as an additive in the production of Portland cement. Other FGD materials—obtained in dry and semi-dry methods of desulphurisation—have variable phase and chemical compositions, so they do not find industrial applications and are mainly stockpiled in underground mines or open pits. The sulphate-calcium ashes from an AFBC process will probably be used in the cement industry simultaneously as a pozzolanic additive and setting-time regulator, provided that their compositions are constant. Their total supply amounted to ca. 1.5×10⁶ tonnes in 2000, but within 5 years, it should achieve 4.0×10⁶ tonnes.     

Sulphur reduction evaluation of selected high-sulphur Chinese coals

Under a collaborative project between China and UK partners, investigation was carried out on high-sulphur coals from Beisu Coal Mine in Shandong Province and Dizong Coal Mine in Guizhou Province to evaluate the sulphur reduction potential by coal preparation. Extensive evaluation of raw coal samples was carried out for design of optimum sulphur reduction processes. This paper discusses the background to the project and describes the evaluation process. This involved selection and sampling of the coals, determination of their washability characteristics and application of process prediction models to the washability data to assess their sulphur reduction potential. This paper demonstrates the potential of model predictions for the development of optimum desulphurisation processes using latest separation processes and plant design. The study has shown that over 50 wt% of sulphur can be removed from Beisu coal (ash 17.9 wt%, sulphur 4.8 wt%) and over 60 wt% of sulphur from Dizong coal (ash 33.5 wt%, sulphur 5.1 wt%) using latest coal cleaning processes.     

Control of sulphur for spring steel killed by Si–Mn and with low basicity slag

Experiments are carried out in the case of low basicity slag for spring steel killed by Si and Mn, then the changes of the sulphur content, the sulphur distribution ratio L_S and inclusions are investigated. Finally, the effect on desulphurisation of oxygen content in molten steel, the calculated and measured lgL_S and the deep desulphurisation of the vacuum degassing station are discussed. It is found that the most sulphur in liquid steel is mainly removed during the early stage of LF refining. The average sulphur content in steel and the sulphur distribution ratio after the soft bottom-blown are 0.0047% and 115, respectively. It is very accurate and credible to use the L_S model to predict L_S. During the early stage of LF refining, to reduce the oxygen content in steel quickly is very crucial for the rapid desulphurisation of the Si and Mn killed spring steel with low basicity slag. The desulphurisation of molten steel can be further carried out during the VD refining station and it is beneficial to reduce the sulphur content for the control of sulphide in spring steel killed by Si–Mn and with low basicity slag.     

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.     

Bacterial removal of sulphur from three different coals

Three different types of coal were taken for microbial desulphurisation experiments using isolated cultures of Thiobacillus ferrooxidans. The samples were milled and then sieved. The effect of various parameters on microbial desulphurisation of three different coals such as particle size, pH, pulp density, media composition and contact time was studied. The conditions were optimised for the maximum removal of sulphur (91.81 wt% for Rajasthan lignite, 63.17 wt% for Polish bituminous coal and only 9.41 wt% of Assam coal).     

Simultaneous SO2 and NO removal using sorbents derived from rice husks: An optimisation study

In this study, rice husk-derived ash (RHA) was hydrated with CaO and then impregnated with copper to synthesize a sorbent that was subsequently tested for its capacity in simultaneous removal of SO₂ and NO from a simulated flue gas. The effect of various sorbent preparation parameters, including copper loading, RHA/CaO ratio, hydration period and NaOH concentration, on the desulphurisation/denitrification capacity of the sorbents was studied using Design-Expert Version 6.0.6 software. Specifically, central composite design (CCD) coupled with response surface method (RSM) was used. The individual parameters that were found to significantly affect the sorbent capacity were RHA/CaO ratio and NaOH concentration. In addition, the interactive effect between RHA/CaO ratio, hydration period and NaOH concentration was also found to have a significant effect on the sorbent activity. The preparation condition for optimal sorbent activity was found to be CuO loading of 3.0%, RHA/CaO ratio of 1.4, hydration period of 20.0 h and NaOH concentration of 0.2 M. Characterisation of the sorbent was performed using scanning electron microscopy (SEM), X-ray diffraction (XRD) and nitrogen adsorption-desorption method to describe the effect of the sorbent preparation parameters on its desulphurisation/denitrification activity.     

Biogas purification for MCFC application

Biogas from landfills is a powerful renewable fuel that can be used as a feedstock for fuel cell systems. However, it has to be purified of sulphur compounds and halogenated species, which are poisonous for both fuel cells and reforming catalysts. This work presents a benchmarking study on the removal of sulphur and halogenated compounds from a model landfill biogas through adsorption. Six commercial adsorbents have been tested to compare their selectivity and their uptake capacity towards nine different sulphur compounds. A multi-step adsorption process, characterised by a high adsorptive-capacity and rather low costs has been proposed. Two specific activated carbons for the removal of halogenated species have also been tested for the purification of nine chlorinated hydrocarbons that are present in the model biogas. One single system that could completely eliminate the halogenated molecules contained in the biogas could not be found, which indicates the necessity of specific developments.