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Cheng YW, Chong CC, Cheng CK, Wang CH, Ng KH, Witoon T, Lam MK, Lim JW. Long-term evaluation of palm oil mill effluent (POME) steam reforming over lanthanum-based perovskite oxides. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 351:119919. [PMID: 38157572 DOI: 10.1016/j.jenvman.2023.119919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 11/29/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024]
Abstract
To replace the obsolete ponding system, palm oil mill effluent (POME) steam reforming (SR) over net-acidic LaNiO3 and net-basic LaCoO3 were proposed as the POME primary treatments, with promising H2-rich syngas production. Herein, the long-term evaluation of POME SR was scrutinized with both catalysts under the optimal conditions (600 °C, 0.09 mL POME/min, 0.3 g catalyst, & 74-105 μm catalyst particle size) to examine the catalyst microstructure changes, transient process stability, and final effluent evaluation. Extensive characterization proved the (i) adsorption of POME vapour on catalysts before SR, (ii) deposition of carbon and minerals on spent SR catalysts, and (iii) dominance of coking deactivation over sintering deactivation at 600 °C. Despite its longer run, spent LaCoO3 (50.54 wt%) had similar carbon deposition with spent LaNiO3 (50.44 wt%), concurring with its excellent coke resistance. Spent LaCoO3 (6.12 wt%; large protruding crystals) suffered a harsher mineral deposition than spent LaNiO3 (3.71 wt%; thin film coating), confirming that lower reactivity increased residence time of reactants. Transient syngas evolution of both SR catalysts was relatively steady up to 4 h but perturbed by coking deactivation thereafter. La2O2CO3 acted as an intermediate species that hastened the coke removal via reverse Boudouard reaction upon its decarbonation. La2O2CO3 decarbonation occurred continuously in LaCoO3 system but intermittently in LaNiO3 system. LaNiO3 system only lasted for 13 h as its compact ash blocked the gas flow. LaCoO3 system lasted longer (17 h) with its porous ash, but it eventually failed because KCl crystallites blocked its active sites. Relatively, LaCoO3 system offered greater net H2 production (72.78%) and POME treatment volume (30.77%) than LaNiO3 system. SR could attain appreciable POME degradation (>97% COD, BOD5, TSS, & colour intensity). Withal, SR-treated POME should be polished to further reduce its incompliant COD and BOD5.
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Affiliation(s)
- Yoke Wang Cheng
- Faculty of Chemical and Process Engineering Technology, Universiti Malaysia Pahang Al-Sultan Abdullah, Lebuhraya Tun Razak, 26300, Gambang, Kuantan, Pahang, Malaysia; NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower, #15-02, 138602, Singapore, Singapore; Energy and Environmental Sustainability Solutions for Megacities (E2S2), Campus for Research Excellence and Technological Enterprise (CREATE), 138602, Singapore, Singapore.
| | - Chi Cheng Chong
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459, Singapore
| | - Chin Kui Cheng
- Center for Catalysis and Separation (CeCaS), Department of Chemical Engineering, College of Engineering, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Chi-Hwa Wang
- Energy and Environmental Sustainability Solutions for Megacities (E2S2), Campus for Research Excellence and Technological Enterprise (CREATE), 138602, Singapore, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, 117585, Singapore
| | - Kim Hoong Ng
- Department of Chemical Engineering, Ming Chi University of Technology, New Taipei City, 24301, Taiwan
| | - Thongthai Witoon
- Center of Excellence on Petrochemical and Materials Technology, Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok, 10900, Thailand
| | - Man Kee Lam
- HICoE-Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Department of Chemical Engineering, Universiti Teknologi PETRONAS, 32610, Seri Iskandar, Perak Darul Ridzuan, Malaysia
| | - Jun Wei Lim
- HICoE-Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 32610, Seri Iskandar, Perak Darul Ridzuan, Malaysia; Centre for Herbal Pharmacology and Environmental Sustainability, Chettinad Hospital and Research Institute, Chettinad Academy of Research and Education, Kelambakkam, 603103, Tamil Nadu, India
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