Chemical Engineering Department, Widener University , 1 University Place, Chester, Pennsylvania 19013, United States.
RMX Technologies , 835 Innovation Drive, Suite 200, Knoxville, Tennessee 37932, United States.
Chem Rev. 2016 Oct 12;116(19):11436-11499. doi: 10.1021/acs.chemrev.5b00745. Epub 2016 Aug 24.
In today's perspective, natural gas has gained considerable attention, due to its low emission, indigenous availability, and improvement in the extraction technology. Upon extraction, it undergoes several purification protocols including dehydration, sweetening, and inert rejection. Although purification is a commercially established technology, several drawbacks of the current process provide an essential impetus for developing newer separation protocols, most importantly, adsorption and membrane separation. This Review summarizes the needs of natural gas separation, gives an overview of the current technology, and provides a detailed discussion of the progress in research on separation and purification of natural gas including the benefits and drawbacks of each of the processes. The transportation sector is another growing sector of natural gas utilization, and it requires an efficient and safe on-board storage system. Compressed natural gas (CNG) and liquefied natural gas (LNG) are the most common forms in which natural gas can be stored. Adsorbed natural gas (ANG) is an alternate storage system of natural gas, which is advantageous as compared to CNG and LNG in terms of safety and also in terms of temperature and pressure requirements. This Review provides a detailed discussion on ANG along with computation predictions. The catalytic conversion of methane to different useful chemicals including syngas, methanol, formaldehyde, dimethyl ether, heavier hydrocarbons, aromatics, and hydrogen is also reviewed. Finally, direct utilization of methane onto fuel cells is also discussed.
从当前的角度来看，由于天然气排放低、本土供应充足以及提取技术的改进，其受到了广泛关注。在提取之后，它需要经过几个净化步骤，包括脱水、脱硫和惰性气体去除。虽然净化是一种商业上已确立的技术，但当前工艺的几个缺点为开发更新的分离方法提供了重要动力，最重要的是吸附和膜分离。本综述总结了天然气分离的需求，概述了当前的技术，并详细讨论了天然气分离和净化研究的进展，包括每种工艺的优点和缺点。天然气的另一个应用增长领域是运输部门，它需要高效和安全的车载储存系统。压缩天然气（CNG）和液化天然气（LNG）是天然气最常见的储存形式。吸附天然气（ANG）是一种替代的天然气储存系统，与 CNG 和 LNG 相比，ANG 在安全性以及温度和压力要求方面具有优势。本综述详细讨论了 ANG 以及计算预测。甲烷到包括合成气、甲醇、甲醛、二甲醚、重质烃、芳烃和氢气等不同有用化学品的催化转化也进行了综述。最后，还讨论了甲烷直接用于燃料电池的问题。
