School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.
School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Energy Saving and Emission Reduction for Metallurgical Industry, University of Science and Technology Beijing, Beijing 100083, China.
Sci Total Environ. 2021 Jul 1;776:145835. doi: 10.1016/j.scitotenv.2021.145835. Epub 2021 Feb 14.
Complete depolymerization of scrap tires (ST) to valuable oil products and fuel gas could be achieved by supercritical water (SCW) technology. For implementing this promising technology, migration mechanism of sulfur element during the entire ST-SCW depolymerization process was identified to reduce the sulfur pollutions. In the depolymerization process of ST, OH radicals released from SCW molecules could enhance cleavage of CS bonds, resulting sulfur-containing intermediates. The intermediates could be further oxidized by free OH radicals and transformed into inorganic sulfur molecules mainly consisting of SO, SO, SO and S. In this study, a combined ReaxFF-MD and DFT method was performed to study the detailed sulfur migration mechanism during ST depolymerization in the presence of SCW and provided a strategy to fix low-valent sulfur in aqueous solution for separation of sulfur from the oil & gas products. This work provides a guidance to make ST-SCW technology cleaner and cheaper.
通过超临界水（SCW）技术可以实现废旧轮胎（ST）的完全解聚，生成有价值的油产品和燃料气。为了实现这一有前途的技术，确定了在整个 ST-SCW 解聚过程中硫元素的迁移机制，以减少硫污染。在 ST 的解聚过程中，SCW 分子释放的 OH 自由基可以增强 CS 键的断裂，生成含硫中间体。这些中间体可以进一步被游离的 OH 自由基氧化，并转化为主要由 SO、SO、SO 和 S 组成的无机硫分子。在这项研究中，采用 ReaxFF-MD 和 DFT 相结合的方法，研究了在 SCW 存在下 ST 解聚过程中硫的详细迁移机制，并提供了一种在水溶液中固定低价硫的策略，以将硫从油和气产品中分离出来。这项工作为使 ST-SCW 技术更清洁、更廉价提供了指导。
