Ing. Prof. Nana Yaw Asiedu | Kwame Nkrumah University of Science and Technology, Kumasi Ghana (original) (raw)

Papers by Ing. Prof. Nana Yaw Asiedu

Analytical and bioanalytical chemistry/Analytical & bioanalytical chemistry, Jun 18, 2024

Annals of Nuclear Energy, 2023

$Research paper thumbnail of Improved phase fraction measurement via non-intrusive optical sensing for vertical upward gas -liquid flow$

Gas Science and Engineering

This paper presents the design and application of a non-intrusive optical sensor for the accurate... more This paper presents the design and application of a non-intrusive optical sensor for the accurate measurement of phase fractions under a vertical upward gas-liquid flow. The sensor was made of two pairs of emitter and photo receivers operated at a wavelength of 1480 nm. The measurement principle of the sensor is based on the disparity in refractive indexes of gas and liquid that provides a proportional relationship between the phase fraction and light intensity. A flow regime dependent calibration model was then developed which corrects for structural scattering derived from the calibrated sensor responses. The model was able to measure local and average phase fractions under varied flow regimes with errors of ± 1.25% and ± 2% relative to photography and swell level methods respectively with a combined uncertainty of ± 2.3%. Comparisons of the non-intrusive optical sensor with the homogenous, Drift flux and Armard phase fraction correlations showed reasonable agreements. The concept of slip as a dominant effect for flow regime in the slug, churn and annular flow regimes accounted for these disparities. The work demonstrates the efficacy of a low cost, non-intrusive method to determine phase fraction in two phase flow over a wide range of flow conditions.

Industrial Biotechnology, 2016

Abstract The fermentation of cassava extracts in brewing is often hampered by microbial inhibitor... more Abstract The fermentation of cassava extracts in brewing is often hampered by microbial inhibitors and oscillations from product and substrate inhibitions, which often decrease ethanol yields. Previous evaluation of the modeling of ethanol inhibition during fermentation of cassava extracts showed low model accuracy. This low model accuracy is due to substrate inhibition, which increases process control challenges. The inhibition patterns considered in this work were linear, sudden growth stop, and exponential. Mathematical models were developed to simulate substrate and product inhibitions during the fermentation of cassava extracts for alcohol production. The results obtained showed substrate and product inhibitions exist during fermentation of cassava extracts, with inhibition patterns being linear substrate-exponential product, exponential substrate-exponential product, and linear substrate-linear product inhibitions. The obtained models are described with a high degree of accuracy (99% confidence inte...

Biomass, Biorefineries and Bioeconomy

The drive for a sustainable society and a circular economy has motivated researchers around the g... more The drive for a sustainable society and a circular economy has motivated researchers around the globe to turn to the transformation of renewable raw materials like biomass into value-added products that are akin or superior to their fossil counterparts. Among these biomass raw materials, cocoa pod husks (CPH) which is the non-edible portion of cocoa (ca. 70–75% weight of the while cocoa fruit) remains a promising bio-resource raw material for the production high-value added chemicals but yet largely underexploited. Currently, the most popular applications of CPH involves its use as low-value application products such as animal feed, raw material for soap making, and activated carbon. However, the rich source of lignocellulosic content, pectin, and phenolic compounds of CPH means it could be used as raw materials for the production industrially relevant platform chemicals with high potential in the agrochemicals, pharmaceutical, and food industries, if efficient transformations route...

Computers & Chemical Engineering

This paper presents a theoretical framework to model anaerobic digester structures and define per... more This paper presents a theoretical framework to model anaerobic digester structures and define performance targets using regions of attainability constructed using kinetic models and fundamental processes: mixing and biodegradation. Two digestion cases, diary manure (case 1) and diary manure + lagoon inoculum (case 2) were considered and the following main findings were obtained. Case 1 presents a linear acidogenic and exponential methanogenic uncoupling, an optimized performance target of 216.45% with optimal digester structure consisting of CSTR (continuous stirred reactor) + PFR (plug flow reactor) run in parallel with a CSTR (6 days retention time, RT) or a CSTR with bypass from feed (2 days RT). Case 2 presents a linear methanogenic response, an optimized target of 142.47% with optimal digester structure consisting of a CSTR + PFR with bypass (2 & 6 days RT). The framework presented in this study can be used for simultaneous optimization of performance targets and digester networks.

SSRN Electronic Journal, 2021

Environmental Quality Management, 2022

Environmental concerns and cost associated with drilling operations have made us promote the appl... more Environmental concerns and cost associated with drilling operations have made us promote the application of biodegradable and renewable drilling fluid additives, particularly at high temperature. In this study, sodium carboxymethyl cellulose (NaCMC) synthesized from cocoa pod husk (cocoa NaCMC) was tested as a filtration agent at high temperature and differential pressure conditions. Moreover, eight mud samples containing various fluid-loss additives were tested. The Filtration test was performed using the permeability plugging tester at 248 °F temperature and 100 psi and 300 psi differential pressures with ceramic discs 10 µm and 90 µm. In addition, the degree filtration agents affect the drilling mud’s rheological parameters were estimated. Also, thermal degradability of the sample was also studied. The results showed that filtration control performance at high temperature and low/high differential pressure was improved by decreasing particle size and increasing concentration. Usi...

SN Applied Sciences, 2021

The utilization of bio-based technology for energy has piqued researchers' curiosity around t... more The utilization of bio-based technology for energy has piqued researchers' curiosity around the world. As a result, bioethanol fermentation has been a hot topic of research for many scientists since it uses less energy and chemicals, produces fewer harmful by-products and emissions, and has environmentally favorable applications. The modeling and simulations of one-dimensional product and substrate inhibitions for sorghum, maize, and cassava extracts are discussed in this paper. Because it provides an edge over other methodologies, mechanistic modeling techniques are used. Models of substrate and product inhibitions in one dimension (1-D) are constructed. These 1-D models are then confirmed using parameter estimates before being employed in the work's simulations. For each dynamic model constructed, model fitness coefficients (α) are calculated. For the product, the exponential inhibition model, sorghum extract data has the best model fitness coefficient (α = 0.4088), for pr...

Valorization of Biomass to Value-Added Commodities, 2020

In recent years, the drive toward a sustainable economy has challenged the scientific community t... more In recent years, the drive toward a sustainable economy has challenged the scientific community to pursue ambitious investigations to convert sustainable feedstocks such as lignocellulose into useful products. These products include biofuels, commodity chemicals, and new bio-based materials including bioplastics, which offer a potential substitution to the dwindling nonrenewable fossil resources. A plethora of lignocellulosic biomass processing technologies have been attempted and effectively documented in literature, which include, but not limited to, biochemical, liquid acid, thermochemical, and catalytic (homogeneous and heterogeneous catalysis) transformation processes. This chapter reviews the state-of-the-art research and development of these process technologies. We further highlight the advantages and disadvantages, potential for future applications, challenges related to these technologies, and opportunities to maximize economic and environmental benefits, while minimizing waste and pollution. Special emphasis is placed and discussed on the production of biofuels and commodity chemicals from these process technologies. Besides, the application of molecular modeling in integration with experiments is highlighted in this chapter as a new paradigm for mechanism study and thus could open up new avenues to design and develop catalysts for a plethora of biomass reactions that require high activity and selectivity.

Industrial & Engineering Chemistry Research, 2020

The blend of mathematical modeling with process data affords both meaningful qualitative and quan... more The blend of mathematical modeling with process data affords both meaningful qualitative and quantitative interpretation of outcomes which may advance our knowledge of microbial physiology and even...

Scientific African, 2019

The design of biogas reactors for blackwater treatment provides special challenges due to signifi... more The design of biogas reactors for blackwater treatment provides special challenges due to significant variability in blackwater characteristics, the complexity of biological systems, and the need, in many cases, to operate in an extremely hygienic environment. In this study, mathematical models were formulated based on microbial growth kinetics to analyze the anaerobic codigestion of blackwater with kitchen waste as well as compare different substrate mixing ratios. The modelling approach used has the advantage of simulating the process with very little input data and eliminates the need to quantify the viable bacteria biomass, which is usually very difficult to estimate during anaerobic digestion. The validity of models is assessed by using a new statistical coefficient (α), which cumulates the effect of four known parameters: coefficient of determination (R 2), adjusted coefficient of determination (R 2 Adj), reduced chi-square (χ 2) and root mean square error (RMSE). A numerical calculation interface was designed to quickly and cheaply simulate different digestion scenarios, display results to user and evaluate the effect of input variation on the system's dynamics. Three simulation cases studies were considered each with different mixing ratios of black water to kitchen waste: Case 1 (50:50), Case 2 (25:75) and Case 3 (pure kitchen waste). The, Moser and Andrew based models were most appropriate in describing biogas kinetics for case study 1 (α-values of 0.2238 and 0.2596 respectively), the Monod and Moser based models most appropriate for case 2 (α-values of 0.0987 and 0.1266 respectively), while the Bergter and Haldane based models were most appropriate for case 3 (α-value of 0.0348 and 0.0347 respectively). The results of this study can be used to facilitate design and optimization of biogas sanitation units treating blackwater and kitchen waste.

Computers & Chemical Engineering, 2019

Anaerobic digesters are seldom designed based on process kinetics, but rather on a combination of... more Anaerobic digesters are seldom designed based on process kinetics, but rather on a combination of hydraulic and organic loading, which may limit operational performance. This study focuses on the incorporation of process kinetics in the design of anaerobic digesters, within the attainable region conceptual framework. Candidate attainable regions for anaerobic digesters are identified using the software environment Biodigester Rapid Analysis and Design System (B-RADeS), which couples, biodegradation kinetics as well as economic parameters for the synthesis of biodigester structures. By considering swine, palm oil and pharmaceutical wastewaters, payback periods of 0.5, 1 & 2 years, and substrate, kinetic model and/or economic parameters, a promising digester structure (and associated hydraulic retention times) is synthesized, consisting of a CSTR followed by PFR (15 days), CSTR (4.8 hours) and a PFR with bypass of feed (3 days). The framework offers great promise for widespread practical application.

Bioresource Technology, 2019

This study sets out to develop an approach that couples attainable regions and fuzzy multicriteri... more This study sets out to develop an approach that couples attainable regions and fuzzy multicriteria decision methods for modeling optimal configurations of multistage digesters without using a kinetic model of the process. The approach is based on geometric analysis of methane curves as their shapes contain valuable insight into substrate biodegradability characteristics during anaerobic digestion. With the case study of abattoir waste, the results indicate that the optimal batch operation policy involves four anaerobic sequencing batch reactors operated in series with fresh feed being added at the second and the four stages (fed-batch systems). For continuous mode operation, the optimal configuration involves a continuous stirred tank digester with bypass from feed followed by an anaerobic baffled digester, which has been used to obtain a novel prototype. The methodological framework presented in this study can be adopted to enhance design of multistage anaerobic digesters especially when reliable kinetic models are unavailable.

Cogent Chemistry, 2019

as soon as possible after acceptance. Copyediting, typesetting, and review of the resulting proof... more as soon as possible after acceptance. Copyediting, typesetting, and review of the resulting proof will be undertaken on this manuscript before final publication of the Version of Record (VoR). Please note that during production and pre-press, errors may be discovered which could affect the content.

Water Research, 2019

Unlike high-rate anaerobic digesters that employ some mechanism to retain microbial sludge mass, ... more Unlike high-rate anaerobic digesters that employ some mechanism to retain microbial sludge mass, lowrate systems use sufficiently long hydraulic retention times to ensure process stability, which becomes economically unattractive for treating large quantities of waste. This study presents the use of attainable region to develop a new strategy to enhance the stability of low-rate digesters. By considering three digestion cases, diary manure only (batch 1) or diary manure with granular (batch 2) or lagoon (batch) sludge as innoculum, the following findings were obtained. (1) For a given concentration of volatile acids in an anaerobic digester, higher concentrations of methanogenic archae can be attained using a digester structure (combination of different digesters) as opposed to single digester. (2) For a given digested substrate, a change in the source of inoculum results in a change in the limits of achievability by the system (attainable limits for batches 1, 2 and 3 were 46.486(g/L) 2 , 5.562(g/L) 2 and 0.551(g/L) 2 , which resulted in performance improvements of 118.604%,175.627% and 200.436% respectively), and hence optimal digester structure. The evidence from this study suggests that the technique can be used to simultaneously improve process stability, define performance targets and propose digester structures required to achieve a given target.

Heliyon, 2019

High performance clay swelling inhibitors play a vital role in improving inhibition characteristi... more High performance clay swelling inhibitors play a vital role in improving inhibition characteristics of shales. The linkages between the inhibition's characteristics of the non-ionic surfactant extract from bio-based inhibitors are yet to be fully explored in the literature. This paper reports the use of a crude extract containing saponins from Chromolaena odorata (CO) leaf, which act as surfactants for inhibiting shale hydration. Determination of the inhibitive property of nonionic surfactant was made through measurements of surface-active properties, inhibition tests, filtration, rheological and strength test. The experimental findings on CO showed that it was highly compatible and very stable with conventional water-based drilling fluids (WBDFs), a highly effective shale inhibitor and a works through plugging and viscosity acting effect in the shale system.

Industrial Crops and Products, 2018

Bio-Oils derived from biomass pyrolysis are promising feedstock for the direct production of valu... more Bio-Oils derived from biomass pyrolysis are promising feedstock for the direct production of valuable platform chemicals, fuels and energy from renewable and sustainable resources. Among the numerous technologies utilized for biomass pyrolysis, fast pyrolysis technologies are chosen for liquid products yield maximization, and characterized by short residence times for solids and vapors, operating temperatures in above ≥500°C and very high heating rates. Inspired by the vast potential of biomass pyrolysis bio-oils, a thermochemical conversion (fast pyrolysis) and characterization of cocoa pod husks, an abundant agricultural biomass waste from Ghana, West Africa, has been investigated and their potential as renewable feedstock for the production of high-value added chemicals determined by analyzing chemical components of the derived bio-oil. GC-MS analysis of the bio-oil indicated that major constituents were 9, 12-octadecadienoic acid and hexadecanoic acid". Product distributions revealed 58%wt. of bio-oil, 30%wt. of bio-char and 12%wt. of Non-condensable gas (obtained by difference). Ultimate, proximate, structural composition, calorific value and thermogravimetry analyses were also performed on the cocoa pod husks. Elemental analysis showed that the recovered milled cocoa pod husks contained about 7 elements potentially essential for plant growth.

Applied Energy, 2019

Digester networks as opposed to single digesters improves anaerobic treatment. • We introduced th... more Digester networks as opposed to single digesters improves anaerobic treatment. • We introduced the use of attainable regions to model anaerobic digester networks. • A physical and geometric classification of methane bioreactor types are presented. • Technique uses process kinetics to define performance targets and digester networks. • Attainable regions and optimized parameters differ for each digested substrate.