Biography

Dr. Ngigi holds a PhD in Energy studies from Moi University (2024), MSc in Chemical Engineering from Moi University (2016) and B. Tech, Chemical & Process Engineering from Moi University (2001). He is a registered Graduate Engineer with Engineers Board of Kenya (EBK) and a Registered Graduate Member, Institution of Engineers of Kenya (IEK). He has vast experience in the private sector having worked for Kenol-Kobil and Menengai Oil Refineries. He is a trained Internal QMS Auditor (by SGS) and Online teaching by PEDAL. His current research interest focuses on Renewable Energy, Enzyme Immobilization, Modelling and Simulation.

Recent Publications

Ngigi, W., et al., 2022. Predicting the techno-economic performance of a large-scale second-generation bioethanol production plant: a case study for Kenya. International Journal of Energy & Environmental Engineering (IJEEE), 13(2). Website Abstract

This study investigates the effect of varying cost and process parameters on bioethanol production rate and the minimum bioethanol selling price (MBSP) during large-scale production of second-generation bioethanol from Sila sorghum stalks found in Kenya. Aspen Plus was used to model and simulate the process that was considered in this study. The flow rate of biomass was varied between 10,000 and 300,000 kg/h which gave rise to a bioethanol flow rate of between 2134.49 and 62,707.33 kg/h. Bioethanol production rate decreased from 21,759.5 to 19,397.6 kg/h when the feed stage position in the beer column increased from 2 to 8. MBSP increased from $0.81/L to $1.11/L when the cost of biomass was varied from $20/tonne to $100/tonne. MBSP increased from $0.9/L to $1.0/L when the cost of enzymes was varied by − 50% and + 50%. MBSP increased from $0.83/L to $1.54/L when discount rate varied by 5% and 30%. MBSP increased from $0.85/L to $1.06/L when fixed capital investment was varied by -35% and + 35%. MBSP reduced from $1.28/L to $0.95/L when plant life varied from 10 to 30 years. MBSP increased from $0.89/L to $0.99/L when income tax rate varied from 0 to 40%. The study indicates that second-generation bioethanol is able to compete with gasoline in Kenya when no levies and taxes are imposed on the MBSP, at a plant life of 15 years and beyond and at an income tax rate of between 0 to 40%.

Ngigi, W.T., 2017. PRODUCTION OF BRIQUETTES FROM Prosopis juliflora STEM AND ANTHILL SOIL. International Journal novel Res. phys. chem. mathematics, 4(2), p.22-27.

Ngigi, W.T., 2017. Optimizing the Conversion of Pretreated Sila Sorghum Stalks to Simple Sugars Using Immobilized Enzymes.

Ngigi, W.T., 2017. PRODUCTION OF BUILDING BOARDS FROM WASTE PLASTICS BLENDED WITH SILA SORGHUM STALKS USING MOLASSES AS COUPLING AGENT. International Journal of Novel Research in Engineering and Science, 4(1). Website

Wiseman Tumbo Ngigi

Lecturer, Chemical and Process Engineering

Biography

Recent Publications

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