Superior Sorbents for Desulfurization of Gas and Liquid Fuels by Adsorption

目前，液体运输燃料的阳脱硫是通过高温高压催化过程完成的，而天然气的脱硫是通过使用胺的溶剂萃取法进行的。这些都是成本高昂、能源密集的过程。吸附脱硫法是一种简单、低能耗的脱硫法。由于缺乏好的吸着剂，它没有被使用。本实验室发现了一类pi-络合脱硫剂，与已知的所有脱硫剂相比，它具有更高的硫选择性和更高的硫容量，并且这种pi-络合脱硫剂是完全可再生的。天然气和运输燃料的脱硫都是如此。我们实验室只探索了非常有限的能够与硫分子形成pi络合键的阳离子。此外，只有数量非常有限的大孔基质被研究为pi络合吸附剂的载体。我们最近的研究表明，无论是气体还是液体燃料的脱硫，孔扩散对固定床吸附的硫容量都有严重的限制。在这项提案中，系统地研究了最有前景的介孔、大孔、pi络合脱硫剂，用于气体和液体燃料的脱硫。最有希望的d-嵌段金属阳离子的盐和氧化物将以单层形式分散在这些大孔衬底上。这些脱硫剂将具有最高的硫选择性和容量。它们也将是最稳定和完全可再生的。它们将具有大孔，以最大限度地减少扩散阻力，从而提供最高的固定床硫吸附容量。对于这些pi络合吸着剂，将测量纯组分和含硫分子混合物的平衡等温线和孔扩散系数(以扩散时间常数表示)。通过分子轨道理论计算和光谱研究，将对各种pi络合吸附剂上的吸附物种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，将考察使用分散剂在高比表面积衬底上分散单层pi络合盐的可能好处。测定了气体燃料和液体燃料在各种新型吸附剂上的固定床吸附穿透曲线。将对硫磺容量的扩散限制有一个了解。该项目将吸引各种研究生和本科生，特别是少数族裔和女性学生的积极参与。学生们将在全国会议和出版物上积极传播这些发现和发现。这项研究将带来气体和液体燃料的全新脱硫技术，从而以更低的成本生产更清洁的燃料。硫含量较低的清洁燃料将减少向大气中排放的硫。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中。此外，还将对含硫分子与d-嵌段金属之间的成键(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.