Superior Sorbents for Desulfurization of Gas and Liquid Fuels by Adsorption

目前液体运输燃料的脱硫是通过高温高压催化工艺来完成的，而天然气的脱硫是通过胺类溶剂萃取来完成的。这些都是昂贵且能源密集的过程。吸附脱硫是一种简单、低能的脱硫方法。由于缺乏良好的吸附剂，它没有被使用。在我们的实验室中发现了一类pi络合吸附剂，与所有已知的吸附剂相比，它具有更高的硫选择性和更高的硫容量，并且pi络合吸附剂是完全可再生的。天然气和运输燃料的脱硫都是如此。在我们的实验室中，只有非常有限数量的阳离子能够与硫分子形成pi络合键。此外，只有非常有限数量的大孔底物被研究作为pi络合吸附剂的支撑。我们最近的研究表明，对于气体和液体燃料的脱硫，孔扩散导致固定床吸附的硫容量受到严重限制。在本提案中，系统地研究了最有前途的中孔、大孔、双络合吸附剂，用于气体和液体燃料的脱硫。最有前途的d嵌段金属阳离子的盐和氧化物将以单层形式分布在这些大孔基质上。这些吸附剂将具有最高的硫选择性和容量。它们也是最稳定和完全可再生的。它们将具有较大的孔隙，以尽量减少扩散阻力，从而提供最高的固定床对硫的吸附能力。对于这些pi-络合吸附剂，将测量纯组分和含硫分子混合物的平衡等温线和孔隙扩散系数（根据扩散时间常数）。通过分子轨道理论计算和光谱研究，将对各种pi络合吸附剂的吸附物质和成键有一个基本的了解。通过研究金属的分散性和稳定性，我们将探讨使用分散剂在高表面积基底上扩散单层pi-络合盐的可能好处。固定床吸附器突破曲线将测量气体和液体燃料在各种新的吸附剂。将获得对硫容量的扩散限制的理解。这个项目将涉及到研究生和本科生的积极参与，特别是少数民族和女学生。学生们将积极参与在国家会议上和通过出版物传播这些发现和发现。这项研究将带来气体和液体燃料脱硫的全新技术，从而以更低的成本生产更清洁的燃料。含硫量较低的清洁燃料将减少硫排放到大气中。在这项工作中开发的吸附剂可以很容易地转移到工业应用。此外，还将对含硫分子与d嵌段金属之间的键（即pi-络合键）有一个基本的了解。

0852129YangDesulfurization of liquid transportation fuels is currently accomplished by high temperature and high pressure catalytic processes, while desulfurization of natural gas is performed by solvent extraction using amines. These are costly and energy intensive processes. Desulfurization by adsorption would be a simple and low-energy process. It is not being used because of the lack of good sorbents. A class of pi-complexation sorbents has been discovered in our laboratory that has higher sulfur selectivities and higher sulfur capacities compared to all previously known sorbents, and the pi-complexation sorbents are fully regenerable. This is the case for desulfurization of both natural gas and transportation fuels. Only a very limited number of cations that are capable of forming pi-complexation bonds with sulfur molecules have been explored in our laboratory. Also, only a very limited number of large pore substrates have been studied as supports for pi-complexation sorbents. Our most recent studies showed that for both gas and liquid fuel desulfurization, pore diffusion causes severe limitation on the sulfur capacity in fixed-bed adsorption. In this proposal, a systematic study of the most promising mesoporous, largepore, pi-complexation sorbents for desulfurization of both gaseous and liquid fuels is outlined. Salts and oxides of the most promising d-block metal cations will be spread in monolayer form on these large-pore substrates. These sorbents will have the highest sulfur selectivities and capacities. They will also be most stable and fully regenerable. They will have large pores in order to minimize diffusion resistance and consequently provide the highest fixed-bed adsorption capacities for sulfur. Equilibrium isotherms and pore diffusivities (in terms of diffusion time constants) for both pure-component and mixtures of sulfur-containing molecules will be measured for these pi- complexation sorbents. A basic understanding of the adsorbed species and bonding on various pi-complexation sorbents will be obtained through molecular orbital theory calculations as well as spectroscopic studies. The possible benefit of using a dispersant for spreading monolayer pi- complexation salts on high-surface-area substrates will be examined by studying the metal dispersion and stability. Fixed-bed adsorber breakthrough curves will be measured for both gas and liquid fuels on various new sorbents. An understanding of the diffusion limitation on sulfur capacity will be obtained. This project will involve active participation of a diversity of graduate as well as undergraduate students, particularly the minority and female students. The students will be active in disseminating the findings and discoveries at national meetings and through publications. The research will lead to entirely new technologies for desulfurization of both gaseous and liquid fuels, which will result in cleaner fuels at lower costs. Cleaner fuels with lower sulfur contents will reduce sulfur emission into the atmosphere. The sorbents developed in this work can be readily transferred to industrial applications. In addition, a basic understanding on the bonding between sulfur containing molecules and d-block metals (i.e., pi- complexation bonds) will be obtained.