A New Clean Coal Technology by Mild Modification at Low Temperature

为了开发一种以煤矸石和低阶煤为原料制备高性能H_2S吸收剂的新方法，我们进行了以下工作：（1）提出了一种新的吸收剂制备方法。(2)新型吸收剂脱除H_2S的性能(3)利用铁废料在钢铁厂中的应用首先，我们尝试了一种新的制备H_2S吸收剂的方法：将低阶煤在70 ℃下用硝酸氧化2h，引入大量的羧基官能团，然后进行铁离子交换。铁交换后的煤在500 ℃下热解，在800 ℃下气化。热解后的Fe转变为FeC，气化后的Fe转变为Fe_3O_4。气化后铁的重量含量约为0.01%。百分之八十通过SEM观察发现，20-50 nm的Fe_3O_4颗粒高度分散在Fe/C复合物中。在此基础上，研究了Fe/C复合物作为H_2S吸收剂的性能。比较了新型吸收剂和传统吸收剂的脱H_2S性能。采用该方法制备的吸收剂具有良好的脱硫性能。X射线衍射分析表明，Fe_3O_4经H_2S处理后转变为FeS。认为Fe/C复合物的物理（纳米粒子的高度分散性）和化学（纯Fe_3O_4）特性是该吸附剂高性能的主要原因。结果表明，这些废弃物对H2S有明显的吸附作用。此外，我们还证实了用该方法制备的吸附剂对H_2S有很好的脱除效果。说明该方法是制备高性能H_2S吸收剂的有效方法。

In order to develop a new method for producing a high performance absorbent of H_2S based on the waste and low rank coal, we performed the following items:(1) Proposal of a new preparation method of absorbent.(2) Performance of the removal of H_2S by a new absorbent.(3) Application of iron wastes in steel factory.First, we tried a new method to produce an absorbent of H_2S as follows: The low rank coal was oxidized for 2 h at 70 ℃ by nitric acid to introduce a large amount of carboxyl functional group and was exchanged by Fe ion. The Fe-exchanged coal was pyrolyzed at 500 ℃ and gasified at 800 ℃ under steam. Though the treatment the type of Fe changed into FeC after pyrolysis and Fe_3O_4 after gasification. The weight content of Fe after gasification was ca. 80 %. We found that the Fe_3O_4 particles of 20-50 nm in size were highly dispersed in the Fe/carbon complex from the observation by SEM. Thus, an attractive Fe/carbon complex was successfully produced.Next, we examined the performance of Fe/carbon complex as a absorbent of H_2S. We compared the de-H_2S profiles of new and conventional absorbents. A absorbent prepared by the proposed method had a high performance of desulfurization. From the X-ray analysis the Fe_3O_4 was converted into FeS after exposing by H_2S. It was supposed that the high performance of a new absorbent was brought about by physical (the highly dispersed nano particles) and chemical (pure Fe_3O_4) properties of Fe/carbon complex.Finally, we applied the proposed method to iron wastes in steel factory such as iron sludge and dust. It was found that these wastes were significantly absorbed H2S. Furthermore, we confirmed that the adsorbent prepared by the proposed method form these wastes had a high de-H_2S performance. Thus it was clarified that the proposed method is effective for producing a high performance absorbent of H_2S.