激冷镍基合金脱硫吸附剂的研究

STUDY ON THE REMOVAL OF SULFUR FROM DIESEL FUEL USING Ni-BASED RAPID-QUENCHING ALLOY AS ADSORBENT

测定了不同金属组成的激冷镍基合金(RQ-Ni)吸附剂的硫容,考察了硫容较大的 RQ-Ni吸附剂在不同操作条件下对柴油中硫化物的吸附性能,探索了吸附剂的吸附机理、再生方法和再生机理。结果表明,采用RQ-Ni吸附剂对柴油进行脱硫的最佳条件为:吸附温度300℃、空速 10 h-1、氢气通入量50 mL／min、常压。每克吸附剂一次可处理柴油25～30 g,在有效吸附时间 (150～180 min)内,脱硫率为60％～90％。吸附过程中通入氢气可改善柴油颜色,采用水蒸气在 300℃吹扫吸附剂可恢复脱硫活性。该吸附剂的吸附机理为:柴油中硫化物在金属镍基吸附剂上发生了离解吸附,硫碳键在金属和H2的共同作用下断裂,S留在金属上形成硫化镍;不同结构硫化物与吸附剂作用不同,导致其脱硫率的差异;水蒸气再生可恢复活性的原因是由于硫化镍与H2O 反应生成NiO和Ni2O3。

The sulfur adsorbing capacities of various Ni-based Rapid-Quenching Alloy （RQ-Ni） adsorbents were determined and their performance of removing sulfur compounds from diesel fuel was investigated under different operating conditions. The mechanism of desulfurization and the regeneration of the adsorbents were studied as well. Test results showed that the optimal operating conditions were under atmospheric pressure, with an adsorption temperature of 300 ℃, a WHSV of 10 h^-1 and a hydrogen flow rate of 50 mL/min. Under said operating conditions 25--30 g of diesel fuel could be treated on per gram of alloy for once through, and a desulfurization rate range of 60%～90% was obtained within an effective adsorption time of 150--180 min. It was suggested that the desulfurization mechanism was as follows, the chemisorbed sulfur compounds were dissociated on the adsorbent and the sulfurcarbon bonds were broken under the co-action of metal and hydrogen, thus forming NiS; the differences in desulfurization rates were due to the different reaction activities between the adsorbent and the sulfur compounds having various intrinsic molecular structures. The presence of hydrogen improved the color of treated diesel due to the suppression of inferior by-reactions. The adsorbent could be regenerated by steam stripping since NiS could react with water to form NiO and Ni2O3.