【摘要】 在固定床中考察2种高硫煤半焦水蒸汽部分气化预脱硫的行为.结果表明:硫的气化脱除因煤而异,大同半焦的脱硫率随着温度的升高而增加,义马半焦在温度高于700℃时,由于灰分中碱性矿物质的固硫作用,脱硫率降低;气化剂水蒸汽含量提高有利于半焦中碳和硫的析出,且可抑制灰分中碱性矿物质的固硫作用,使半焦中含硫量降低;增加气速有利于改善传质,使生成的气相硫快速移出反应区,提高脱硫率;在初始阶段,半焦停留时间的增加可有效降低部分气化半焦的含硫量,增加脱硫率;但随着反应的进行,脱硫率逐渐升高,脱硫速度减缓.水蒸汽部分气化可改善煤焦结构,有利于硫的脱除;大同和义马半焦中无机硫化物脱除率分别达94%和64%.更多还原

【Abstract】 The pre-desulfurization of high-sulfur coal chars during partial gasification were investigated in a fixed-bed reactor. The chars were prepared from Datong and Yima coals. The variables studied include temperature, reacting gas composition, gas velocity, and char’s residence time. The results show that the sulfur removal depends on characteristics of coal chars. The sulfur removal increases with the rise of temperature for Datong coal char. While for Yima coal char, at a temperature higher than 700 ℃, the desulfuration rate decreases because of the fixed-sulfur effect of alkaline metals in ash. The increase of H₂O in gasification agent can improve sulfur removal and reduce sulfur content in chars obviously, and can inhibit the effects of fixed-sulfur by alkaline metals. The increase of gas velocity can strengthen mass transfer, remove the sulfur in gas phase from the reaction zone, and promote sulfur removal. A long residence time can reduce the sulfur content in chars at the first stage of gasification, but the sulfur removal rates turn down according to the mass-transfer limitation. The comparison of treated and untreated chars shows that, after the treatment, the pores are ’opened up’, indicating an easier access for the reacting gas to the interior of the char, which is desirable for sulfur removal. The sulfide sulfur is removed effectively during partial gasification process, with the removal rate of Datong and Yima coal chars being 94% and 64%, respectively.更多还原