A chemical looping scheme of co-feeding of coke-oven gas and pulverized coke toward polygeneration of olefins and ammonia

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 334; pp. 1754 - 1765
• Main Authors: Xiang, Dong, Xiang, Junjie, Liu, Shuai, Sun, Zhe, Jiang, Yong, Dong, Zhongbing, Tao, Quanbao, Cao, Yan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.02.2018
• Subjects: Ammonia; Chemical looping combustion; Coke-oven gas-to-olefins; Process coupling and integration; Pulverized coke; Pulverized coke; Ammonia; Coke-oven gas-to-olefins; Process coupling and integration; Chemical looping combustion
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2017.11.156

•Proposed a new process of pulverized coke CLC-assisted COG-to-olefins & ammonia.•Improved olefins capacity by 25% with additional 0.4 Mt/y ammonia for the new process.•The co-feeding process resulted in exergy saving by 13% with an IRR increase of 5.6%. The coke-oven gas (COG)-to-olefins (CGTO) process is an important technical path of coal chemical industry. However, it is far more effective and friendly in terms of energy efficiency and environment impact. A new scheme of pulverized coke (PC) chemical looping combustion (CLC)-assisted COG-to-olefins and ammonia (PCCLC-CGTOA) is proposed in this paper. The intensive energy and material couplings in the new process are realized by applying an energy-efficient and environmental-friendly CLC technology to the current CGTO. The PCCLC-derived CO2 is an effective carbon source to adjust ideal composition of syngas toward olefins production, while the PCCLC-derived N2 with the excessive H2 in COG is used for producing ammonia. The process configuration is flexibly adapted to market demand of olefins and ammonia in terms of economic optimization. Process modelling helps its process integration and intensification, and confirms its competitiveness and feasibility. The proposed PCCLC-CGTOA acclaims 58% of hydrogen utilization and 65% of exergy efficiency, contrasting to only 29% and 52% in the CGTO. There is a 25% increase of olefins production with additional 0.4 Mt/y ammonia output at the cost of economic PC. A higher internal rate of return is also expected (18.5% for the PCCLC-CGTOA versus 12.9% for the CGTO).