Comprehensive energy analysis and integration of coal-based MTO process

• Published in: Energy (Oxford) 2021-01, Vol.214, p.119060, Article 119060
• Main Authors: Liu, Shuoshi, Yang, Lu, Chen, Bokun, Yang, Siyu, Qian, Yu
• Format: Article
• Language: English
• Subjects: Coal; Design engineering; Economics; Energy; Energy consumption; Energy integration; Energy recovery; Heat exchange; Heat exchanger network synthesis; Heat exchangers; Heat transfer; Integration; Methanol to olefins; Network synthesis; Optimization; Process simulation; Profitability; Steam; Techno-economic analysis; Water purification
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2020.119060

With low oil prices, the existing coal-to-olefin enterprises are forced to improve profitability by reducing energy consumption. This paper studies the comprehensive energy analysis and integration of coal-based MTO process. Process simulation is established first and is validated by comparing with the industrial data. Energy analysis of the MTO process was then conducted, calculating relevant information of each heat exchange stream. The heat exchanger network synthesis was proposed by using gradual optimization integration strategy based on the T-H diagram. It was found that the hot energy of purified water and steam condensate could be fully utilized. The cold energy of ethylene tower could replace partial −24 °C refrigerant. It was also found that there is the possibility of multi-stage heat transfer in this process. The maximum energy recovery is achieved under the principle of energy cascade utilization and stepwise matching. The result showed that the new design decreases the utility duty and the required exchanger area by 4.76% and 8.63% compared with the industrial process. The capital cost, operation cost and total annual cost of total site are 8.17, 14.64 and 17.27 million $, which are 8.29%, 2.78% and 3.66% less than the industrial design. •Process simulation of whole MTO process is established.•HEN synthesis is proposed by using gradual optimization integration strategy.•The new design decreases utility duty by 4.76%.•The new design decreases the required exchanger area by 8.63%.•The new design saves total annual cost of total site by 3.66%.