Title: Flowsheet development for the steam gasification of animal manure with subsequent CO₂ capturing using CaO: an Aspen Plus^® modelling study

Authors: Muhammad Shahbaz; Tareq Al-Ansari; Ahmed AlNouss; Gordon McKay

Addresses: Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University (HBKU), Qatar Foundation, P.O. Box 5825, Doha, Qatar ' Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University (HBKU), Qatar Foundation, P.O. Box 5825, Doha, Qatar ' Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University (HBKU), Qatar Foundation, P.O. Box 5825, Doha, Qatar ' Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University (HBKU), Qatar Foundation, P.O. Box 5825, Doha, Qatar

Abstract: Animal manure is one of the important wastes present in the state of Qatar and worldwide. The aim of the current investigation is to develop a flowsheet model for the steam gasification of animal manure with CaO for CO₂ capturing using Aspen Plus through the Gibbs-free energy minimisation model. The effect of the three key variables, namely, the temperature (600°C-800°C), the steam/manure ratio of (0.5-2), and the CaO/manure ratio of (0-2) on syngas production was analysed. The CO₂ content reduced from 19 to less than 1 vol% and the H₂ increased from 66 vol% to 98 vol% by varying the CaO/manure ratio from 0-2 at a high temperature of 700°C and steam/manure ratio of 1.5. Whereas the CO₂ reduced from 15 vol% to 11 vol% at an elevated temperature of 850°C. The cost of H₂/kg is $40.44/kg with CaO and $43.17/kg without CaO showing the benefits of its usage. The calculated rate of return and payback period for the manure gasification without CaO utilisation demonstrate higher values than the case with CaO utilisation at approximately 56.60% and 1.77 years compared to 49.02% and 2.04 years, respectively.

Keywords: animal manure; CO₂ capturing; gasification; Aspen Plus; syngas; CaO; CO₂ emissions; cost; techno economic analysis.

DOI: 10.1504/IJGW.2021.118999

International Journal of Global Warming, 2021 Vol.25 No.3/4, pp.259 - 270

Received: 13 Aug 2020
Accepted: 14 Nov 2020
Published online: 17 Nov 2021 *

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