Modeling and analysis of air combustion and steam regeneration in methanol to olefins processes

Light olefins is the incredibly important materials in chemical industry. Methanol to olefins (MTO), which provides a non-oil route for light olefins production, received considerable attention in the past decades. However, the catalyst deactivation is an inevitable feature in MTO processes, and regeneration, therefore, is one of the key steps in industrial MTO processes. Traditionally the MTO catalyst is regenerated by removing the deposited coke via air combustion, which unavoidably transforms coke into carbon dioxide and reduces the carbon utilization efficiency. Recent study shows that the coke species over MTO catalyst can be regenerated via steam, which can promote the light olefins yield as the deactivated coke species can be essentially transferred to industrially useful synthesis gas, is a promising pathway for further MTO processes development. In this work, we modelled and analyzed these two MTO regeneration methods in terms of carbon utilization efficiency and technology economics. As shown, the steam regeneration could achieve a carbon utilization efficiency of 84.31%, compared to 74.74% for air combustion regeneration. The MTO processes using steam regeneration can essentially achieve the near-zero carbon emission. In addition, light olefins production of the MTO processes using steam regeneration is 12.81% higher than that using air combustion regeneration. In this regard, steam regeneration could be considered as a potential yet promising regeneration method for further MTO processes, showing not only great environmental benefits but also competitive economic performance. (c) 2023 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.