中孔-微孔吸附树脂耦合吸附汽油油气新技术的应用基础研究

Gasoline vapor is a mixture containing a variety of hydrocarbon compounds. The emission of gasoline vapor not only has serious hazard to urban atmospheric environment and directly influence human health, but also results in significant energy loss. In this study, a pressure swing adsorption process was put forward to treat the gasoline vapor, in which adsorption bed was packed with hydrophobic mesoporous and microporous polymeric adsorbents simultaneously. However, the design of such adsorption systems needs accurate data about adsorption equilibrium and adsorption-desorption kinetics for the assorted adsorbent-gasoline pair. The surrogate gasoline vapor mixture of butane, hexane and benzene，which are as representatives of the light, heavy and aromatic components in gasoline vapor, respectively, were chosen as adsorbates. The adsorption equilibrium and kinetics of ternary mixture of butane, heptane and benzene on hydrophobic mesoporous polymer and microporous hypercrosslinked polymeric adsorbent were investigated, respectively. The mechanism of competitive adsorption of butane, hexane and benzene on two adsorbents was discussed. Moreover, the adsorption and desorption characteristics of ternary mixture in fixed bed packed with mesoporous and microporous polymeric adsorbents under adiabatic conditions were investigated. A theoretical model was built to simulate adsorption of ternary VOCs mixture on mesoporous and hypercrosslinked polymeric adsorbents in a fixed bed. This model was validated on a set of experimental data. The model obtained appears to be a practical means for designing the high-efficiency adsorption bed of polymeric adsorbents for gasoline vapor removal.

汽油油气是含多种碳氢化合物的混合物，对城市大气环境和人体健康有严重的危害，而且挥发所造成的能源损耗巨大。基于中孔吸附树脂和微孔超高交联吸附树脂的不同吸附特性，本项目创新地提出了高浓度汽油油气回收的“中孔吸附树脂-微孔超高交联树脂组合固定床的变压吸附技术”。为有效指导“中孔-微孔吸附树脂耦合吸附技术”在汽油油气回收中的应用，本项目以汽油油气中轻、重烷烃和芳香烃代表性化合物丁烷、正己烷和苯混合物为研究对象，开展三组分VOCs在不同孔结构的中孔吸附树脂和超高交联树脂上的吸附平衡、吸附和脱附动力学性能研究，阐明树脂孔分布和吸附质物性对吸附、脱附的影响机制，以指导吸附树脂孔结构优化；开展三组分VOCs在中孔和超高交联吸附树脂组合固定床上的绝热吸附-脱附研究，阐明各因素对穿透吸附曲线和再生效率的影响规律。基于上述研究结果，建立三组分VOCs固定床绝热吸附传质模型，为工艺开发及工程设计提供技术支撑。

汽油油气排放是大气环境中挥发性有机物（VOCs）的主要来源之一，不仅对环境造成污染，而且其挥发所造成的能源损耗是惊人的。吸附技术单独或与其他技术集成的处理工艺是当前国内外油气回收的主流技术。本项目以汽油油气中典型成分正戊烷、环己烷和甲苯为吸附对象，开展了中孔吸附树脂和超高交联树脂上对单组分、双组分和三组分VOCs的吸附平衡、吸附穿透、吸附动力学和脱附性能研究，开展了中孔和超高交联吸附树脂混合固定床的拟绝热吸附特性研究。研究发现富含微孔的超高交联吸附树脂对低浓度VOCs具有更高的吸附能力，而富含中孔的中孔吸附树脂对高浓度VOCs具有更高的吸附能力；多组分VOCs在超高交联吸附树脂上有强的吸附竞争，而在中孔吸附树脂上则表现为共吸附，基于理想溶液理论的吸附模型能较好地预测多组分吸附平衡；阐明了VOCs在中孔和超高交联吸附树脂孔内扩散过程受微孔孔口和孔内阻力共同控制，建立了基于孔口-孔内双阻力的吸附动力学预测模型；建立了多组分VOCs拟绝热条件下吸附传质和传热模型，对吸附穿透和床层吸附温升曲线有较准确的预测。本项目研究成果可为吸附树脂的结构优化及其在油气吸附处理中应用提供支撑。