Techno-economic analysis of the production of pure CO2 from flue gases via the monoethanolamine and ammonia capture processes

  • Author / Creator
    Ibadin, Elvis E
  • Carbon dioxide (CO2) emissions from fuel combustion have contributed to the overall greenhouse gas emissions worldwide. Carbon capture is a promising technique that could reduce the emission from power plants with the ever-increasing energy demand. Research into the utilization of CO2 from flue gas is in advanced stage and therefore, there is a need to develop the baseline cost for separation and purification of CO2 from various flue gases. In this study, a detailed process model was developed for carbon capture from flue gases produced in coal-fired power plants and natural gas combined cycle (NGCC) plants using monoethanolamine (MEA)-based solvent. In addition, a detailed techno-economic assessment of the whole process chain of producing pure CO2 using ammonia and monoethanolamine (MEA) based solvents for the flue gas from coal-fired power plants is evaluated and compared. The main operations characterized in this study are the absorption of carbon dioxide with the MEA solution, the regeneration of the MEA solution in the stripper for its reuse and separation, and the compression of CO2 to the desired exit pressure range. The costs of producing pure CO2 through the capture process for a coal-fired power plant with a capacity of 500 MWe at capture rates of 90%, 95%, and 99% are $60.65, $61.57, and $62.16 /tonne CO2, respectively; and for an NGCC plant with a capacity of 555 MWe and the same capture rates are $79.47, $84.44, and $87.07 /tonne CO2, respectively. In comparison, ammonia based solvent, the cost of producing pure CO2 at 90% capture rate for coal flue gases with plant capacity of 500 MWe is 48.42 $/tonne CO2, respectively. Furthermore, the regeneration energy obtained for a 90% capture rate using ammonia solvent is 2.46 GJ/tonne CO2 while that of MEA solvent is 4.62 GJ/tonne CO2. Though there is a significant progress in the use of chilled ammonia process in terms of successful pilot testing, the technical challenge such as ammonia slip should be addressed in order to gain economic acceptability. The comparative results show that ammonia-based solvent is more cost effective than the amine-based solvent due to the high regeneration energy for the later process. The sensitivity analyses show the production cost of pure CO2 is highly sensitive to the capital cost and internal rate of return (IRR). The results of this study will be of interest to investors in chemical processes that intend to use pure CO2 as feedstock and also for jurisdictions such as Alberta where carbon tax policy is already implemented.

  • Subjects / Keywords
  • Graduation date
    Fall 2018
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
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