【作者】 陈振松；

【导师】 杨国华；

【作者基本信息】 宁波大学 ， 轮机工程， 2011， 硕士

【摘要】 焚烧烟气汞排放控制受到国内外普遍重视。目前垃圾焚烧厂广泛采用活性炭喷射+布袋除尘脱汞传统技术,但活性炭的喷射量只占飞灰与活性炭混合物总量的5%,活性炭的利用率和脱汞效率低。为了解决上述问题,提出了纯活性炭粉末+布袋脱汞新技术,在小型布袋脱汞实验台上进行了不同混合比的炭灰混合物脱汞比较实验研究和纯活性炭粉末在布袋除尘器上脱汞影响因素研究。1、不同混合比的炭灰混合物脱汞比较实验研究。结果表明:在80℃的吸附温度下,纯活性炭粉末初次吸附前85min的平均脱汞效率为99.1%,脱汞效率在75%以上的吸附时间为1335min;纯飞灰在初次吸附的前85min的平均脱汞效率仅为19.3%,165min时脱汞效率已经下降为零。纯活性炭粉末掺杂飞灰比例分别为0%、20%、50%、80%、95%时,初次吸附前85min的平均脱汞效率分别为99.1、95、85.3、79.7、59.6、19.3%,脱汞效率在75%以上的累计汞吸附量分别为196.1、172.5、133.8、123.6、21.7μg Hg/g AC。另外,纯活性炭粉末在布袋除尘器上的汞吸附饱和量可达1667μg Hg/g AC。这些结果表明,布袋+纯活性炭粉末脱汞新工艺在脱汞效率和活性炭利用率方面都有明显的优势。2、纯活性炭粉末在布袋除尘器上脱汞影响因素研究。结果表明:吸附温度从80℃上升到170℃时,前65min的平均脱汞效率由99.6%下降到43.2%;吸附温度为100℃,添加体积分数为8% H₂O（g）时,前65min的脱汞效率从无H2O（g）时的75.5%升高到84.6%,但水蒸气含量进一步升高（12%）反而导致脱汞效率降低,纯活性炭粉末的脱汞效率随着活性炭加入量的增加而升高;降低布袋过滤速度能提高纯活性炭粉末脱汞效率;提高汞初始浓度有利于纯活性炭粉末吸附汞。3、以烟气排量为1500000m3/h的300MW燃煤电厂锅炉为例,采用布袋+纯活性炭脱汞新方法,估算活性炭年用量为492吨,约为活性炭喷射+布袋除尘脱汞传统方法的1/9,每年节省活性炭成本1579.2万元。更多还原

【Abstract】 Control of mercury emissions from combustion flue gas has been paid more attention at home and abroad. In mercury capture by activated carbon injection upstream bag filters used widely in MSW at present, the utilization rate and mercury efficiency of activated carbon were very low because the amount of activated carbon was only 5% in the mixture attaching on the surfaces of the bags. The purpose of the current study is to improve Hg0 removal efficiency of activated carbon injection upstream a bag filter and the utilization ratio of powder activated carbon (PAC). Mercury removal experiments were conducted in a small-scale bag filter with different proportions of powder activated carbon (PAC) and fly ash, and and to investigate the influence factors on mercury removal by PAC in bag filter.For comparison, many mercury removal experiments were conducted in a small-scale bag filter with mixture of different proportions of PAC and fly ash. The results indicated that the average mercury removal efficiency (AMRE) was 99.1% within 85 minutes for the first adsorption, and the adsorption time was 1335 minutes with removal efficiency above 75% with pure PAC as sorbent, while the AMRE within 85 minutes for the first adsorption was 19.3% and the removal efficiency fell to nil after 165 minutes with fly ash as the sorbent. The AMRE within 85 minutes for the first adsorption were 99.1% ,95%, 85.3%, 79.7% and 59.6%, and the mercury adsorption capacity with removal efficiency above 75% were 196.1 172.5, 133.8, 123.6 and 21.7μg Hg/g AC with the sorbents of fly ash proportion of 0%, 20%, 50%, 80% and 95% respectively. The PAC had a saturation capacity of 1667μg Hg/g AC at 80℃. These results indicated that the mercury removal technology by pure PAC on bag filter had the obvious superiority in mercury removal efficiency and the utilization ratio of PAC compared to the traditional process by PAC together with fly ash.Experiments on the influence factors on mercury removal by pure PAC in bag filter were performed. The results indicated that the average mercury removal efficiency (AMRE) decreased from 99.6% to 43.2% within 65min as the adsorption temperature increased from 80℃to 170℃, and increased from 75.5% to 84.6% as the volume fraction of flue gas H2O(g) increased from 0% to 8% at 100℃, but the Hg0 removal efficiency reduced instead when H2O(g) content further increased to 12%. Higher PAC mass loading and lower filtration flow velocity could also improve the AMRE of the PAC. The AMRE decreased as the inlet Hgo concentration increased at 150℃.For flue gas of 1500000m3/h in a 300 MW (thermal power) coal-fired power plant boiler, the estimated annual consumption of PAC is about 492 tons with the mercury removal by pure PAC on bag filter, which is only about 1/9 of that by PAC together with fly ash on bag filter, thus it will save $15.792 million RMB in consumption of PAC every year.更多还原