南非煤炭热处理过程中原位捕获和吸收的硫气,ACS Omega

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南非煤炭热处理过程中原位捕获和吸收的硫气
ACS Omega ( IF 3.7 ) Pub Date : 2018-10-26 00:00:00 , DOI: 10.1021/acsomega.8b01359
Ratale H. Matjie ₁ , Jeanett M. Lesufi , John R. Bunt , Christien A. Strydom , Harold H. Schobert ₂ , Romanus Uwaoma

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这项研究的目标是针对这些特定的南非低硫煤进行的首次此类研究，目的是捕获煤中存在的硫化合物，在惰性和氧化条件下产生的H ₂ S和SO ₂。捕获剂是在方解石和白云石转变过程中形成的钙和镁氧化物。两种不同的洗涤溶液（0.15 M乙酸镉和1.1 M氢氧化钾）对挥发的H ₂ S和SO ₂吸收的有效性还进行了调查。烟煤（煤A）包含白云石，方解石，黄铁矿和有机硫。褐煤（煤B）具有高的有机硫含量并且包含石膏，没有或具有低的白云石和黄铁矿含量，并且没有方解石。通过向煤A中添加5 wt％的碳酸钾来制备第三种样品（煤C）。在氧化条件和升高的温度下，FeS ₂产生Fe ₂ O ₃，FeO和SO ₂。它转化为的FeS和释放ħ ₂在惰性条件下S上。在惰性气氛中，有机硫在400°C下与有机结合的钙和镁相互作用，形成硫酸钙和菱铁矿（（Ca，Mg）S）。由方解石或白云石产生的CaO与SO ₂反应和O ₂在950℃下形成硫酸钙。在400–950°C的温度下处理褐煤会导致96–98％的硫以气体形式逸出。在惰性条件下，三种煤的硫化氢生成量随热处理温度的升高而增加。在氧化条件下，加热煤B和C时，二氧化硫的形成随温度的升高而降低。在对煤和碳酸钾（煤C）的混合物进行热处理时，H ₂ S与SO _2的比率最低（0.01）。这意味着几乎所有的硫都保留在煤C灰/炭样品中。通过CaO和MgO以及添加的K ₂ CO ₃原位捕获硫气在煤C中形成钙/镁/钾硫酸钾和钾/钙/镁铝硅酸盐玻璃，在使用这些煤或类似煤时，可将煤中挥发的硫的百分比降低54-100％，从而有可能降低其对环境的影响。

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In Situ Capturing and Absorption of Sulfur Gases Formed during Thermal Treatment of South African Coals

The objective of this study, the first of its kind on these specific South African low-sulfur coals, was to capture H₂S and SO₂ produced under inert and oxidizing conditions from sulfur compounds present in the coals. The capturing agents were calcium and magnesium oxides formed during the transformation of calcite and dolomite. The effectiveness of two different scrubbing solutions (0.15 M cadmium acetate and 1.1 M potassium hydroxide) for absorption of volatilized H₂S and SO₂ was also investigated. The bituminous coal (coal A) contained dolomite, calcite, pyrite, and organic sulfur. Lignite (coal B) had a high organic sulfur content and contained gypsum, no or low dolomite and pyrite contents, and no calcite. A third sample (coal C) was prepared by adding 5 wt % potassium carbonate to coal A. Under oxidizing conditions and at elevated temperatures, FeS₂ produced Fe₂O₃, FeO, and SO₂. It transformed to FeS and released H₂S under inert conditions. Organic sulfur interacted with organically bound calcium and magnesium at 400 °C in an inert atmosphere to form calcium sulfate and oldhamite ((Ca,Mg)S). CaO, produced from calcite or dolomite, reacted with SO₂ and O₂ at 950 °C to form calcium sulfate. Treatment of lignite at 400–950 °C resulted in 96–98% evolution of sulfur as gases. Hydrogen sulfide formation increased with the increasing thermal treatment temperature under inert conditions for the three coals. Under oxidizing conditions, sulfur dioxide formation decreased with the increasing temperature when heating coals B and C. The lowest ratio (0.01) of H₂S to SO₂ was achieved during thermal treatment of the blend of coal and potassium carbonate (coal C), implying that almost all of sulfur was retained in the coal C ash/char samples. In situ capturing of sulfur gases by CaO and MgO and by the added K₂CO₃ in coal C to form calcium/magnesium/potassium sulfates and potassium/calcium/magnesium aluminosilicate glasses during utilization of these and similar coals could reduce the percentage of sulfur volatilized from the coals by 54–100%, thereby potentially decreasing their impact on the environment.

更新日期：2018-10-26

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