Towards Zero CO2 Emissions Power Plant

  • Dalal Almansoori

    Student thesis: Master's Thesis

    Abstract

    Carbon Capture and storage from fossil fuel power plants have gained scientists' attention as an effective method to control greenhouse gas emissions[1]. A post-combustion CO2 capture has been conducted using ASPEN Plus V10 software based on amine absorption /desorption for flue gas from natural gas combined cycle power plant. This optimization aimed to evaluate the potential for natural gas combined cycle (NGCC) power plant with zero carbon dioxide (CO2) emissions using two amine-based solvents [2]. This was achieved by developing and evaluating different CO2 emissions reduction scenarios and processes. In this research, CO2 absorption using Monoethanolamine (MEA) as a solvent was used as the base case. Piperazine (PZ), on the other side, was used as an alternative solvent, and the simulation results were compared with the base case. MEA and PZ, which are amine-based solvents, were successful and promising solvents in capturing CO2. In the base case, 30 wt. % MEA was used as a conventional case, and it led to a capture rate of 90% and 99% CO2 capture in the second case. On the other hand, using a concentrated PZ solution resulted in a 99% capture rate. The Aspen process economic analyzer (APEA) was used to generate the process flow diagram and the economic analysis to compare the advanced PZ-based process's behavior with the results obtained using MEA[3]. The techno-economic evaluation results showed that using a conventional solvent in capturing 90% CO2 leads to the lowest capital expenses (CAPEX) and operating expenses (OPEX) values 221,684,434$/yr and 22,421,047, respectively. While using the same solvent to capture 99%, CO2 leads to the highest value among all cases. The cost of electricity (COE) of the power plant after adding the capturing unit increase approximately by 18-21%. The lowest increase was in the MEA 90% capture process. PZ also yields a low increase in the COE because the PZ process required lower regeneration energy and operating cost than the others. In addition to that, the CO2 avoidance cost of the PZ is lower than MEA processes due to the low electricity needed for utilities and regeneration in the PZ process. The evaluation using biomass as an alternative energy source decreases the COE by approximately (3-5%) and decreases the CO2 avoidance cost by (30-35%). Since the CAPEX and OPEX values of the 90% MEA is the lowest, it is recommended in cases where the cost is more important than the capture rate. While when seeking a 99% capture rate, using PZ with biomass energy is an extremely recommended process. The obtained results were validated using the values presented in the literature, while the economic results for the PZ were considered a contribution of this research since it is a new addition to the research in the CO2 capture field.
    Date of AwardMay 2021
    Original languageAmerican English

    Keywords

    • Carbon Capture
    • Monoethanolamine
    • Post combustion
    • Piperazine
    • Biomass.

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