Abstract:

Molten metal methane pyrolysis is an emerging hydrogen production technology in recent years. Compared with conventional methane pyrolysis and catalytic pyrolysis, it effectively overcomes the problems of high energy consumption, low conversion and catalyst deactivation, and also avoids the high carbon emission as in steam methane reforming technology. The ability to produce value-added solid carbon products along with hydrogen has attracted extensive attention. This article summarizes the latest research and development of methane pyrolysis based on molten metal technology, focusing on the process flow, reaction mechanism, selection of molten medium and rector design etc. We also propose two types of potential reaction mechanisms for elucidating whether the liquid medium plays a catalytic role in methane pyrolysis. Moreover, the selection principle, trends in the development, benefits and drawbacks of different types of molten media are comprehensively elaborated. And the technical economy and greenhouse gas emission reduction also have been discussed, which further demonstrates the feasibility and potential benefits of the process. Finally, suggestions for future technological improvements are presented, and we points out morphology regulation of carbon materials to facilitate transformation into high-value-added products should inevitably become one of the key development directions in the future.

Key words: molten metal, molten salt, methane, pyrolysis, hydrogen, solid carbon products

摘要：

熔融金属法甲烷裂解技术作为近年来新兴的制氢技术，有效地解决了传统甲烷热裂解或催化裂解高能耗、低转化率以及催化剂失活等问题，避免了甲烷蒸汽重整制氢工艺高碳排放。在制氢的同时还能生产出具有附加值的碳产品，因而受到各方广泛关注。本文总结了熔融金属法甲烷裂解技术研究进展，并围绕工艺流程、反应机理、熔融介质的选择以及反应器设计等方面展开，给出了液相介质是否起催化作用的两类甲烷裂解反应机理，并详细阐述了熔融介质选择原则、发展趋势以及不同类型熔融介质的优缺点。再者，技术经济性以及温室气体减排量也在文中详细体现，进一步论证了该工艺的可行性和潜在效益。此外，文中还给出了未来技术发展趋势和建议，指出调控碳材料形貌，使之向高附加值碳材料转变应是未来重点发展方向之一。

关键词: 熔融金属, 熔融盐, 甲烷, 热解, 氢, 碳产品