太西煤一步法制备活性炭及其脱汞性能研究

One step preparation of activated carbon from Taixi coal for mercury removal

活性炭喷射技术(ACI,Activated Carbon Injection)被公认为成熟、可靠的烟气脱汞方法,但活性炭昂贵成本严重影响了该技术的广泛推广。原煤直接活化法生产脱汞活性炭,可以大幅度降低活性炭生产成本。试验以宁夏太西低灰无烟煤为原料用水蒸气直接活化制备活性炭,研究了原煤粒度、活化温度、烧失率对活性炭吸附和脱汞性能的影响。研究发现,原煤粒度为3~4mm,活化温度为910℃,烧失率为71%时,制备的活性炭比表面积最大,高达1 124 m^2/g。脱汞试验结果表明,活性炭脱汞性能受工艺条件影响,但与活性炭比表面积没有明显相关性;经载溴改性后,活性炭的脱汞性能大幅度提升,且与活性炭的比表面积呈现良好相关性。对比研究发现,直接活化法制得的活性炭脱汞性能优于传统方法生产的活性炭。

Activated Carbon Injection （ACI） is recognized as a proven and reliable technology to remove mercury from flue gas. But the high cost of activated carbon has seriously affected its wide application. In this paper, a direct activation technology was proposed to produce activated carbon for mercury removal, which can greatly reduce the production cost of activated carbon. The influences of particle size of raw coal, an anthracite with low content ash from Taixi in Ningxia, the activation temperature, and burn-off rate on the adsorption property and mercury removal performance were studied. It was found that the specific surface area of activated carbon can attain to 1 124 m^2/g under optimized condition, with particle size between 3-4 mm, activation temperature at 910℃ and bum off rate at 71%. The mercury removal experiments showed that the mercury removal performance of raw activated carbon was affected by the processing conditions, but no obvious correlation between mercury performance and the specific surface area of activated carbon was found. But after bromination, the mercury removal performance of activated carbon was greatly enhanced and a good correlation was found. Comparison experiments showed the mercury removal performance of activated carbon obtained by direct activation is better than that of activated carbon by traditional technology.