Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 12) Show all publications
Anukam, A., Mohammadi, A., Naqvi, M. & Granström, K. (2019). A Review of the Chemistry of Anaerobic Digestion: Methods of Accelerating and Optimizing Process Efficiency. Processes, 7(8), 1-19, Article ID 504.
Open this publication in new window or tab >>A Review of the Chemistry of Anaerobic Digestion: Methods of Accelerating and Optimizing Process Efficiency
2019 (English)In: Processes, Vol. 7, no 8, p. 1-19, article id 504Article, review/survey (Refereed) Published
Abstract [en]

The anaerobic digestion technology has been in existence for centuries and its underlying theory established for decades. It is considered a useful technology for the generation of renewable energy, and provides means to alleviate problems associated with low access to energy. However, a great deal of current research is targeted towards the optimization of this technology under diverse digestion process conditions. This review presents an in-depth analysis of the chemistry of anaerobic digestion and discusses how process chemistry can be used to optimize system performance through identification of methods that can accelerate syntrophic interactions of different microorganisms for improved methanogenic reactions. Recent advances in addition to old research are discussed in order to offer a general but comprehensive synopsis of accumulated knowledge in the theory of anaerobic digestion, as well as an overview of previous research and future directions and opportunities of the AD technology. Achieving a sustainable energy system requires comprehensive reforms in not just economic, social and policy aspects, but also in all technical aspects, which represents one of the most crucial future investments for anaerobic digestion systems.

Place, publisher, year, edition, pages
Basel: MDPI, 2019
Keywords
anaerobic digestion, feedstock, syntrophic interaction, process chemistry, methane yield
National Category
Chemical Engineering
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-74884 (URN)10.3390/pr7080504 (DOI)000483747700019 ()
Available from: 2019-09-30 Created: 2019-09-30 Last updated: 2019-10-11Bibliographically approved
Anukam, A., Berghel, J., Famewo, E. B. & Frodeson, S. (2019). Improving the understanding of the bonding mechanism of primary components of biomass pellets through the use of advanced analytical instruments. Journal of wood chemistry and technology, 1-18
Open this publication in new window or tab >>Improving the understanding of the bonding mechanism of primary components of biomass pellets through the use of advanced analytical instruments
2019 (English)In: Journal of wood chemistry and technology, ISSN 0277-3813, E-ISSN 1532-2319, p. 1-18Article in journal (Refereed) Published
Abstract [en]

Previous studies have attempted to explain forces holding particles together in densified biomass pellets using theories of forces of attraction between solid particles, forces of adhesion and cohesion, solid bridges and mechanical interlocking bonds including interfacial forces and capillary pressure. This study investigated the bonding mechanism of primary biomass components in densified pellets through the use of advanced analytical instruments able to go beyond what is visible to the naked eye. Data obtained were used to predict how primary biomass components combine to form pellets based on the theory of functional groups and the understanding of structural chemistry. Results showed that hydroxyl and carbonyl functional groups played key roles in helping to identify the type of forces acting between individual particles, at a molecular level. At a microscopic level, morphological examination of the pellet clearly showed solid bridges caused by intermolecular bonding from highly electronegative polar functional groups linked to cellulose and hemicellulose.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2019
Keywords
Biomass pelleting, bonding mechanism, functional groups, primary components, structural chemistry
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-74768 (URN)10.1080/02773813.2019.1652324 (DOI)000482719600001 ()
Available from: 2019-09-16 Created: 2019-09-16 Last updated: 2019-09-23Bibliographically approved
Anukam, A., Okoh, O., Mamphweli, S. & Berghel, J. (2018). A comparative analysis of the gasification performances of torrefied and untorrefied bagasse: Influence of feed size, gasifier design and operating variables on gasification efficiency. International Journal of Engineering & Technology, 7(2), 859-867
Open this publication in new window or tab >>A comparative analysis of the gasification performances of torrefied and untorrefied bagasse: Influence of feed size, gasifier design and operating variables on gasification efficiency
2018 (English)In: International Journal of Engineering & Technology, E-ISSN 2227-524X, Vol. 7, no 2, p. 859-867Article in journal (Refereed) Published
Abstract [en]

This study conducted a comparative assessment of the gasification performances of torrefied and untorrefied bagasse with emphasis on feed size, gasifier design and operating conditions that would influence gasification efficiency. Torrefaction greatly improved the characteristics of bagasse and had significant impact on its gasification performance. The gasifier design parameters studied were throat angle and throat diameter. Temperature of input air and feed input were the gasifier operating conditions examined in the course of the gasification processes of both torrefied and untorrefied bagasse. These parameters were considered the most critical operating parameters that affect gasifier performance and, correlation between the parameters was established in the course of gasification. The results obtained showed higher gasification efficiency for torrefied bagasse in comparison to untorrefied bagasse under varied conditions of gasification, which was attributed mainly to changes in the characteristics of the torrefied material.  

Place, publisher, year, edition, pages
Science Publishing Corporation, 2018
Keywords
Biomass, Sugarcane Bagasse, Torrefaction, Gasification, Efficiency, Computer Simulation.
National Category
Mechanical Engineering Civil Engineering
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-70365 (URN)10.14419/ijet.v7i2.8489 (DOI)
Available from: 2018-11-29 Created: 2018-11-29 Last updated: 2018-12-13Bibliographically approved
Anukam, A., Mamphweli, S., Okoh, O. & Reddy, P. (2017). Influence of Torrefaction on the Conversion Efficiency of the Gasification Process of Sugarcane Bagasse. Bioengineering, 4(22), 1-23
Open this publication in new window or tab >>Influence of Torrefaction on the Conversion Efficiency of the Gasification Process of Sugarcane Bagasse
2017 (English)In: Bioengineering, E-ISSN 2306-5354, Vol. 4, no 22, p. 1-23Article in journal (Refereed) Published
Abstract [en]

Sugarcane bagasse was torrefied to improve its quality in terms of properties prior to gasification. Torrefaction was undertaken at 300 °C in an inert atmosphere of N2 at 10 °C·min−1 heating rate. A residence time of 5 min allowed for rapid reaction of the material during torrefaction. Torrefied and untorrefied bagasse were characterized to compare their suitability as feedstocks for gasification. The results showed that torrefied bagasse had lower O–C and H–C atomic ratios of about 0.5 and 0.84 as compared to that of untorrefied bagasse with 0.82 and 1.55, respectively. A calorific value of about 20.29 MJ·kg−1 was also measured for torrefied bagasse, which is around 13% higher than that for untorrefied bagasse with a value of ca. 17.9 MJ·kg−1. This confirms the former as a much more suitable feedstock for gasification than the latter since efficiency of gasification is a function of feedstock calorific value. SEM results also revealed a fibrous structure and pith in the micrographs of both torrefied and untorrefied bagasse, indicating the carbonaceous nature of both materials, with torrefied bagasse exhibiting a more permeable structure with larger surface area, which are among the features that favour gasification. The gasification process of torrefied bagasse relied on computer simulation to establish the impact of torrefaction on gasification efficiency. Optimum efficiency was achieved with torrefied bagasse because of its slightly modified properties. Conversion efficiency of the gasification process of torrefied bagasse increased from 50% to approximately 60% after computer simulation, whereas that of untorrefied bagasse remained constant at 50%, even as the gasification time increased.

Place, publisher, year, edition, pages
MDPI, 2017
Keywords
sugarcane bagasse; torrefaction; gasification; efficiency; computer simulation
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-75158 (URN)10.3390/bioengineering4010022 (DOI)
Available from: 2019-10-08 Created: 2019-10-08 Last updated: 2019-10-11Bibliographically approved
Anukam, A., Goso, B. P., Okoh, O. O. & Mamphweli, S. N. (2017). Studies on Characterization of Corn Cob for Application in a Gasification Process for Energy Production. Journal of Chemistry, Article ID 6478389.
Open this publication in new window or tab >>Studies on Characterization of Corn Cob for Application in a Gasification Process for Energy Production
2017 (English)In: Journal of Chemistry, ISSN 2090-9063, E-ISSN 2090-9071, article id 6478389Article in journal (Refereed) Published
Abstract [en]

Quintessential characteristics of corn cob were investigated in this study in order to determine its gasification potential. Results were interpreted in relation to gasification with reference to existing data from the literature. The results showed that the gasification of corn cob may experience some challenges related to ash fouling, slagging, and sintering effects that may be orchestrated by high ash content recorded for corn cob, which may contribute to increasing concentration of inorganic elements under high temperature gasification conditions, even though EDX analysis showed reduced concentration of these elements. The study also found that the weight percentages of other properties such as moisture, volatile matter, and fixed carbon contents of corn cob as well as its three major elemental components (C, H, and O) including its clearly exhibited fiber cells make corn cob a suitable feedstock for gasification. FTIR analysis revealed the existence of -OH, C-O, C-H, and C=C as the major functional group of atoms in the structure of corn cob that may facilitate formation of condensable and noncondensable liquid and gaseous products during gasification. TGA results indicated that complete thermal decomposition of corn cob occurs at temperatures close to 1000 degrees C at a heating rate of 20 degrees C/min.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2017
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-75130 (URN)10.1155/2017/6478389 (DOI)000404418000001 ()
Available from: 2019-10-07 Created: 2019-10-07 Last updated: 2019-10-07Bibliographically approved
Anukam, A., Mamphweli, S., Reddy, P., Okoh, O. & Meyer, E. (2016). Assessment of the Influence of Torrefied Biomass Physical Characteristics, Design and Operating Variables on Gasification Efficiency. Journal of Chemistry and Chemical Engineering (10), 283-292
Open this publication in new window or tab >>Assessment of the Influence of Torrefied Biomass Physical Characteristics, Design and Operating Variables on Gasification Efficiency
Show others...
2016 (English)In: Journal of Chemistry and Chemical Engineering, ISSN 1934-7375, E-ISSN 1934-7383, no 10, p. 283-292Article in journal (Refereed) Published
Abstract [en]

Gasification efficiency is an important factor that determines the actual technical operation as well as the economic viability of using a gasifier system for energy production. In this study, the impact of the physical properties of torrefied bagasse and the influence of gasifier design and operating variables were investigated in a computer simulated downdraft gasification system. Results obtained from the study indicated an interrelationship between feedstock characteristics, especially with regard to feed size, design variables such as throat angle and throat diameter as well as gasifier operating conditions such as temperature of input air and feed input. These variables influenced the efficiency of the gasification process of sugarcane bagasse because of increased enhancement of combustion zone reactions, which liberated huge amount of heat that led to a rise in the temperature of the gasification process. This condition also created increased tar cracking within the gasification system, contributing to reduction in the overall yield of tar.

Place, publisher, year, edition, pages
David Publishing Company, 2016
Keywords
Torrefied bagasse, gasification efficiency, torrefaction, computer simulation, operating variables
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-75159 (URN)10.17265/1934-7375/2016.06.005 (DOI)
Available from: 2019-10-08 Created: 2019-10-08 Last updated: 2019-10-08Bibliographically approved
Anukam, A., Mamphweli, S. N., Mabizela, P. S. & Meyer, E. L. (2016). Blending Influence on the Conversion Efficiency of the Cogasification Process of Corn Stover and Coal. Journal of Chemistry, Article ID 3910986.
Open this publication in new window or tab >>Blending Influence on the Conversion Efficiency of the Cogasification Process of Corn Stover and Coal
2016 (English)In: Journal of Chemistry, ISSN 2090-9063, E-ISSN 2090-9071, article id 3910986Article in journal (Refereed) Published
Abstract [en]

Characterizations of biomass and coal were undertaken in order to compare their properties and determine the combustion characteristics of both feedstocks. The study was also intended to establish whether the biomass (corn stover) used for this study is a suitable feedstock for blending with coal for the purpose of cogasification based on composition and properties. Proximate and ultimate analyses as well as energy value of both samples including their blends were undertaken and results showed that corn stover is a biomass material well suited for blending with coal for the purpose of cogasification, given its high volatile matter content which was measured and found to be 75.3% and its low ash content of 3.3% including its moderate calorific value of 16.1%. The results of the compositional analyses of both pure and blended samples of corn stover and coal were used to conduct computer simulation of the cogasification processes in order to establish the best blend that would result in optimum cogasification efficiency under standard gasifier operating conditions. The final result of the cogasification simulation process indicated that 90% corn stover/10% coal resulted in a maximum efficiency of about 58% because conversion was efficiently achieved at a temperature that is intermediate to that of coal and corn stover independently.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2016
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-75133 (URN)10.1155/2016/3910986 (DOI)000381144900001 ()
Available from: 2019-10-07 Created: 2019-10-07 Last updated: 2019-10-07Bibliographically approved
Anukam, A., Mamphweli, S. N., Reddy, P. & Okoh, O. O. (2016). Characterization and the effect of lignocellulosic biomass value addition on gasification efficiency. Energy exploration & exploitation, 34(6), 865-880
Open this publication in new window or tab >>Characterization and the effect of lignocellulosic biomass value addition on gasification efficiency
2016 (English)In: Energy exploration & exploitation, ISSN 0144-5987, E-ISSN 2048-4054, Vol. 34, no 6, p. 865-880Article in journal (Refereed) Published
Abstract [en]

Value addition to lignocellulosic biomass materials such as sugarcane bagasse to produce multiple bio-based products which includes synthesis gas is becoming a dynamic research area. Pre-treatment techniques to improve the quality of biomass are essential for the successful application of the feedstock in energy production systems. This study investigated changes in the composition of sugarcane bagasse subjected to torrefaction as a preparation of bagasse for gasification. Characterization of the torrefied bagasse was undertaken in terms of proximate and ultimate analyses as well as in terms of energy value. The results were used to conduct a computer simulation of the gasification process of the torrefied bagasse. The gasification process results confirmed that torrefied bagasse is a suitable feedstock for gasification in terms of conversion efficiency, which was found to be approximately 42% when compared to untorrefied sugarcane bagasse, with a conversion efficiency of about 40% achieved in our previous study.

Place, publisher, year, edition, pages
Sage Publications, 2016
Keywords
Sugarcane bagasse, torrefaction, gasification, conversion efficiency
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-75132 (URN)10.1177/0144598716665010 (DOI)000386855900005 ()
Available from: 2019-10-07 Created: 2019-10-07 Last updated: 2019-10-07Bibliographically approved
Anukam, A., Mamphweli, S., Reddy, P., Meyer, E. & Okoh, O. (2016). Pre-processing of sugarcane bagasse for gasification in a downdraft biomass gasifier system: A comprehensive review. Renewable & sustainable energy reviews, 66, 775-801
Open this publication in new window or tab >>Pre-processing of sugarcane bagasse for gasification in a downdraft biomass gasifier system: A comprehensive review
Show others...
2016 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 66, p. 775-801Article, review/survey (Refereed) Published
Abstract [en]

The processing of sugarcane bagasse as a potential feedstock for efficient energy production has attracted a great deal of attention in the sugarcane industry, which has traditionally inefficiently burned bagasse in boilers for steam and electricity generation. Alternative technologies for more efficient utilisation of bagasse for energy production within the industry has also been hindered by the high degree of complexity involved in bagasse handling and pre-processing before it can be utilised as an energy feedstock. This can be attributed to unfavourable characteristics of mill-run bagasse, which includes low bulk and energy densities, a wide range of particle sizes and shapes as well as high moisture content. Gasification is regarded as one of the most promising energy recovery technologies for the widespread use of biomass because of its higher efficiency when compared to the combustion technology commonly used by the sugarcane industry. There has been a strong drive to identify efficient pre-processing methods that can be applied to bagasse to make it a suitable feedstock for energy production in thermochemical conversion systems. This work provides a comprehensive review on the pre-processing of bagasse for gasification, and the gasification technology options for its conversion into energy, with a particular emphasis on the downdraft gasification technology. (C) 2016 The Authors. Published by Elsevier Ltd.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Sugarcane bagasse, Biomass, Gasification, Pre-processing, Downdraft gasifier, Process efficiency
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-75131 (URN)10.1016/j.rser.2016.08.046 (DOI)000386403200049 ()
Available from: 2019-10-07 Created: 2019-10-07 Last updated: 2019-10-07Bibliographically approved
Anukam, A., Mamphweli, S., Reddy, P., Okoh, O. & Meyer, E. (2015). An Investigation into the Impact of Reaction Temperature on Various Parameters during Torrefaction of Sugarcane Bagasse Relevant to Gasification. Journal of Chemistry, Article ID 235163.
Open this publication in new window or tab >>An Investigation into the Impact of Reaction Temperature on Various Parameters during Torrefaction of Sugarcane Bagasse Relevant to Gasification
Show others...
2015 (English)In: Journal of Chemistry, ISSN 2090-9063, E-ISSN 2090-9071, article id 235163Article in journal (Refereed) Published
Abstract [en]

Torrefaction of sugarcane bagasse was conducted in an electric muffle furnace at 200, 250, and 300 degrees C in order to establish the impact of heat treatment temperature on various parameters and as a method to improve sugarcane bagasse characteristics for the purpose of gasification. The results show that weight loss of bagasse reduced as temperature of torrefaction increased due to excessive devolatilization. A reduced moisture and volatile matter content as well as improved calorific value were also achieved with increasing temperature of torrefaction. The torrefaction progress was again followed by elemental analysis of the material which showed the presence of C, H, and O in varying proportions depending on torrefaction temperature. The decrease in the weight percentages of O-2 and H-2 as torrefaction reaction temperature increased resulted in the accumulation of C in the solid product. The thermogravimetric analysis conducted established the maximum reactivity temperature of the torrefied material and revealed that the degradation of torrefied sugarcane bagasse was accelerated by thermal treatment of the material prior to analysis. Finally, the study established that torrefaction at 300 degrees C led to a much more degraded material compared to the lower torrefaction reaction temperatures of 200 and 250 degrees C, respectively.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2015
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-75134 (URN)10.1155/2015/235163 (DOI)000367303000001 ()
Available from: 2019-10-07 Created: 2019-10-07 Last updated: 2019-10-07Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4574-1713

Search in DiVA

Show all publications