摘要
研究了用于吸附分离的乙苯吸附剂及其吸附行为。以NaX和NaY吸附剂小球为载体,通过交换多种金属阳离子制备出不同离子类型的X型或Y型沸石吸附剂。通过静态吸附平衡实验筛选出优先吸附乙苯的CsX分子筛吸附剂。构建了CsX分子筛晶胞模型,计算C_8芳烃的吸附热及吸附等温线。实验结果表明,乙苯和对二甲苯在CsX分子筛上发生了竞争吸附的行为,即只有二者同时存在的条件下CsX分子筛才优先地吸附乙苯。CsX分子筛为吸附剂模型的元素组成为Cs_(51)Na_(32)Al_(83)Si_(109)O_(384),硅铝比为2.6,Cs^+交换度为61.4%;Rietveld精修结果的可靠性系数为26.65%,与实际结构接近。通过分子模拟的方法计算了高吸附容量下的吸附热,吸附位的不同可能是导致发生竞争吸附的原因之一。
X and Y zeolite adsorbents with different cations were prepared by exchanging metallic cations with NaX and NaY spheres as supports, and were used in the adsorptive separation of ethylbenzene（EB） from C8 aromatics. Through static adsorption experiments, the CsX adsorbent that could preferentially adsorb EB was selected. The crystal cell model of the CsX zeolite was established, and the adsorption heats and adsorption isotherms of the C8 aromatics were calculated. It was showed that, there was competitive adsorption between the p-xylene（PX） and EB molecules, and in the presence of both PX and EB, CsX preferentially adsorbed EB. When the CsX zeolite was chosen as the adsorbent model, the elemental composition, silica-aluminum oxide ratio and Cs＋ exchange degree were Cs51Na32Al83Si109O384, 2.6 and 61.4%, respectively. The result was reliable. The adsorption heats at high adsorption capacity were calculated and it was showed that different adsorption sites were one of the factors leading to the competitive adsorption between EB and PX.
出处
《石油化工》
CAS
CSCD
北大核心
2016年第6期707-712,共6页
Petrochemical Technology
基金
中国石化石油化工科学研究院项目(R15068)
关键词
乙苯吸附剂
吸附分离
分子模拟
吸附热
C8芳烃
ethylbenzene adsorbent
adsorption separation
molecular simulation
adsorption heat
C8 aromatics
