Dr ORLA WILLIAMS's Outputs (44)

Novel Thermal and Microscopic Techniques To Determine the Causes of Suboptimal Combustion Performance at Colombian Stoker Furnaces (2022)
Journal Article
Williams, O. S. A., Daley, P., Perkins, J., Shah, S., Saavedra, E. A. G., Trujillo, M., Barraza-Burgos, J., Espitia, C. J., Barajas, M., Saltaren, J. S., Gil, N. J., & Lester, E. H. (2022). Novel Thermal and Microscopic Techniques To Determine the Causes of Suboptimal Combustion Performance at Colombian Stoker Furnaces. ACS Omega, 7(14), 11618–11630. https://doi.org/10.1021/acsomega.1c06314

This study presents the application of a novel approach, using thermal and optical techniques, to identify the causes of poor burnout performance of Colombian stoker furnaces in the Cauca Valley State. The four coals used in these furnaces were char... Read More about Novel Thermal and Microscopic Techniques To Determine the Causes of Suboptimal Combustion Performance at Colombian Stoker Furnaces.

Predictability of higher heating value of biomass feedstocks via proximate and ultimate analyses – A comprehensive study of artificial neural network applications (2022)
Journal Article
Güleç, F., Pekaslan, D., Williams, O., & Lester, E. (2022). Predictability of higher heating value of biomass feedstocks via proximate and ultimate analyses – A comprehensive study of artificial neural network applications. Fuel, 320, Article 123944. https://doi.org/10.1016/j.fuel.2022.123944

Higher heating value (HHV) is a key characteristic for the assessment and selection of biomass feedstocks as a fuel source. The HHV is usually measured using an adiabatic oxygen bomb calorimeter; however, this method can be time consuming and expensi... Read More about Predictability of higher heating value of biomass feedstocks via proximate and ultimate analyses – A comprehensive study of artificial neural network applications.

Upgrading of Low-Grade Colombian Coals via Low-Cost and Sustainable Calcium Nitrate Dense Media Separation (2022)
Journal Article
Williams, O. S. A., Daley, P., Perkins, J., Martinez-Mendoza, K. L., Guerrero-Perrez, J., Mazabuel, L. M. S., Saavedra, E. A. G., Trujillo, M., Barraza-Burgos, J., Barajas, M., Romero, M. H., & Lester, E. H. (2022). Upgrading of Low-Grade Colombian Coals via Low-Cost and Sustainable Calcium Nitrate Dense Media Separation. ACS Omega, 7(4), 3348-3358. https://doi.org/10.1021/acsomega.1c05346

Wet coal beneficiation in Colombia is prohibitive due to the high cost and scarcity of commonly used dense media. The practical value of this study is that it demonstrates for the first time that a common fertilizer, calcium nitrate, can be used in t... Read More about Upgrading of Low-Grade Colombian Coals via Low-Cost and Sustainable Calcium Nitrate Dense Media Separation.

Hydrothermal conversion of different lignocellulosic biomass feedstocks - Effect of the process conditions on hydrochar structures (2021)
Journal Article
Güleç, F., Riesco, L., Williams, O., Kostas, E. T., Samson, A., & Lester, E. (2021). Hydrothermal conversion of different lignocellulosic biomass feedstocks - Effect of the process conditions on hydrochar structures. Fuel, 302, Article 121166. https://doi.org/10.1016/j.fuel.2021.121166

Five biomass feedstocks (Coffee residues, Rice waste, Whitewood, Zilkha black, and Lignin) were hydrothermally processed in a semi-continuous flow rig using 9 different processing conditions (75, 150, 250 °C, and 1, 50, 240 bar). Solid residues produ... Read More about Hydrothermal conversion of different lignocellulosic biomass feedstocks - Effect of the process conditions on hydrochar structures.

Understanding Layered Double Hydroxide properties as sorbent materials for removing organic pollutants from environmental waters (2021)
Journal Article
Johnston, A.-L., Lester, E., Williams, O., & Gomes, R. L. (2021). Understanding Layered Double Hydroxide properties as sorbent materials for removing organic pollutants from environmental waters. Journal of Environmental Chemical Engineering, 9(4), Article 105197. https://doi.org/10.1016/j.jece.2021.105197

Emerging contaminants (ECs) are a group of anthropogenic organic pollutants known to have a host of adverse environmental and health implications. The removal of such pollutants from aqueous environments to ensure water is of a quality fit for reuse... Read More about Understanding Layered Double Hydroxide properties as sorbent materials for removing organic pollutants from environmental waters.

A Passive RFID Tag For Biomass Tracking (2020)
Presentation / Conference Contribution
Ali, A., Mackenzie, R., Lester, E., Williams, O., & Greedy, S. (2020, March). A Passive RFID Tag For Biomass Tracking. Presented at 2020 14th European Conference on Antennas and Propagation (EuCAP), Copenhagen, Denmark

© 2020 EurAAP. This paper presents the design for a low cost miniaturized chipless RFID tag for short-range biomass tracking and monitoring purposes. The concentric hexagonal geometry and angular stability, leading to higher data capacity are the nov... Read More about A Passive RFID Tag For Biomass Tracking.

Experimental data on morphological characterization of chars from coal and bagasse blends (2020)
Journal Article
Garcia, E., Barraza-Burgos, J., Guerrero, J., Trujillo, M., Lester, E., & Williams, O. (in press). Experimental data on morphological characterization of chars from coal and bagasse blends. Data in Brief, 29, Article 105358. https://doi.org/10.1016/j.dib.2020.105358

© 2020 The Authors Morphological characterization of chars from coal and bagasse plays an important role in both the burning efficiency and intrinsic reactivity of chars, during a combustion process [1], [2]. In this work, abundant data on the morpho... Read More about Experimental data on morphological characterization of chars from coal and bagasse blends.

Microwave pyrolysis of olive pomace for bio-oil and bio-char production (2019)
Journal Article
Williams, O. S., Kostas, E. T., Durán-Jiménez, G., Shepherd, B. J., Meredith, W., Stevens, L. A., Robinson, J. P., & Lye, G. J. (2020). Microwave pyrolysis of olive pomace for bio-oil and bio-char production. Chemical Engineering Journal, 387, Article 123404. https://doi.org/10.1016/j.cej.2019.123404

Olive pomace is a widely available agro-industrial waste residue in Europe that has the potential to contribute towards a circular, low carbon bio-economy. This study demonstrated, for the first time, the ability to successfully pyrolyse olive pomace... Read More about Microwave pyrolysis of olive pomace for bio-oil and bio-char production.

Automated image analysis techniques to characterise pulverised coal particles and predict combustion char morphology (2019)
Journal Article
Perkins, J., Williams, O., Wu, T., & Lester, E. (2020). Automated image analysis techniques to characterise pulverised coal particles and predict combustion char morphology. Fuel, 259, Article 116022. https://doi.org/10.1016/j.fuel.2019.116022

A new automated image analysis system that analyses individual coal particles to predict daughter char morphology is presented. 12 different coals were milled to 75-106 µm, segmented from large mosaic images and the proportions of the different petro... Read More about Automated image analysis techniques to characterise pulverised coal particles and predict combustion char morphology.

Formation of Metallurgical Coke within Minutes through Coal Densification and Microwave Energy (2019)
Journal Article
Williams, O., Ure, A., Stevens, L., Binner, E., Dodds, C., Kingman, S., Das, B., Dash, P. S., & Lester, E. (2019). Formation of Metallurgical Coke within Minutes through Coal Densification and Microwave Energy. Energy and Fuels, 33(7), 6817-6828. https://doi.org/10.1021/acs.energyfuels.9b00511

This paper shows how feedstock densification gives rise to a step change in the time required to create a metallurgical grade coke using microwave energy. Five densified coking and non-coking coals were heated in a multi-mode microwave 2450 MHz cavit... Read More about Formation of Metallurgical Coke within Minutes through Coal Densification and Microwave Energy.

The impact of ash pellet characteristics and pellet processing parameters on ash fusion behaviour (2019)
Journal Article
Daley, P., Williams, O., Pang, C. H., Wu, T., & Lester, E. (2019). The impact of ash pellet characteristics and pellet processing parameters on ash fusion behaviour. Fuel, 251, 779-788. https://doi.org/10.1016/j.fuel.2019.03.142

The Ash Fusion Test (AFT) is considered to be the most popular method of characterising the melt characteristics of solid fuel ash. This study shows how pellet preparation can make significant improvements to repeatability. Pelleting pressure, pellet... Read More about The impact of ash pellet characteristics and pellet processing parameters on ash fusion behaviour.

Microwave pyrolysis of Laminaria digitata to produce unique seaweed-derived bio-oils (2019)
Journal Article
Kostas, E. T., Williams, O. S., Duran-Jimenez, G., Tapper, A. J., Cooper, M., Meehan, R., & Robinson, J. P. (2019). Microwave pyrolysis of Laminaria digitata to produce unique seaweed-derived bio-oils. Biomass and Bioenergy, 125, 41-49. https://doi.org/10.1016/j.biombioe.2019.04.006

Microwave pyrolysis has become an attractive form of processing technology to generate bio-oil, bio-char and syngas from different biomass feedstocks. In this study, microwave pyrolysis was performed on the UK native seaweed Laminaria digitata and it... Read More about Microwave pyrolysis of Laminaria digitata to produce unique seaweed-derived bio-oils.

Removal of copper from cattle footbath wastewater with layered double hydroxide adsorbents as a route to antimicrobial resistance mitigation on dairy farms (2018)
Journal Article
Williams, O., Clark, I., Gomes, R. L., Perehinec, T., Hobman, J. L., Stekel, D. J., Hyde, R., Dodds, C., & Lester, E. (2019). Removal of copper from cattle footbath wastewater with layered double hydroxide adsorbents as a route to antimicrobial resistance mitigation on dairy farms. Science of the Total Environment, 655, 1139-1149. https://doi.org/10.1016/j.scitotenv.2018.11.330

Copper and zinc are routinely used in livestock antimicrobial footbaths in commercial farming. The footbath mix is a cost to farmers, and the disposal of spent footbath into slurry tanks leads to soil contamination, as well as the potential for antim... Read More about Removal of copper from cattle footbath wastewater with layered double hydroxide adsorbents as a route to antimicrobial resistance mitigation on dairy farms.

Applicability of mechanical tests for biomass pellet characterisation for bioenergy applications (2018)
Journal Article
Williams, O., Taylor, S., Lester, E., Kingman, S., Giddings, D., & Eastwick, C. (2018). Applicability of mechanical tests for biomass pellet characterisation for bioenergy applications. Materials, 11(8), Article 1329. https://doi.org/10.3390/ma11081329

In this paper, the applicability of mechanical tests for biomass pellet characterisation was investigated. Pellet durability, quasi-static (low strain rate), and dynamic (high strain rate) mechanical tests were applied to mixed wood, eucalyptus, sunf... Read More about Applicability of mechanical tests for biomass pellet characterisation for bioenergy applications.

A proposed biomass char classification system (2018)
Journal Article
Lester, E., Avila, C., Pang, C. H., Williams, O., Perkins, J., Gaddipatti⁠, S., Tucker, G. A., Barraza, J. M., Trujillo-Uribe, M. P., & Wu, T. (2018). A proposed biomass char classification system. Fuel, 232, https://doi.org/10.1016/j.fuel.2018.05.153

A new classification system is proposed for the morphological characterisation of char structures from biomass. These char structures are unlike the coal chars that have an established nomenclature via the International Committee of Coal and Organic... Read More about A proposed biomass char classification system.

Benefits of dry comminution of biomass pellets in a knife mill (2017)
Journal Article
Williams, O., Lester, E., Kingman, S., Giddings, D., Lormor, S., & Eastwick, C. (in press). Benefits of dry comminution of biomass pellets in a knife mill. Biosystems Engineering, 160, https://doi.org/10.1016/j.biosystemseng.2017.05.011

The potential benefits of dry comminution in a knife mill for a diverse range of biomass 6 pellets are explored. The impact of dry comminution on energy consumption, particle size and shape, 7 is examined as well as the link between milling and mecha... Read More about Benefits of dry comminution of biomass pellets in a knife mill.

Overcoming the caking phenomenon in olive mill wastes (2017)
Journal Article
Williams, O., Eastwick, C., Kingman, S., Giddings, D., Lormor, S., & Lester, E. (2017). Overcoming the caking phenomenon in olive mill wastes. Industrial Crops and Products, 101, https://doi.org/10.1016/j.indcrop.2017.02.036

The use of olive mill wastes (orujillo) within coal fired power stations in the UK has led to unexpected difficulties with material caking within the fuel handling plant. This study replicated orujillo caking on a laboratory scale using a planetary b... Read More about Overcoming the caking phenomenon in olive mill wastes.

Influence of mill type on densified biomass comminution (2016)
Journal Article
Williams, O., Newbolt, G., Eastwick, C., Kingman, S. W., Giddings, D., Lormor, S., & Lester, E. (2016). Influence of mill type on densified biomass comminution. Applied Energy, 182, 219-231. https://doi.org/10.1016/j.apenergy.2016.08.111

The impact of different mill fracture mechanisms were examined for a wide range of densified biomass pellets to provide a comprehensive analysis of biomass milling behaviour for pulverised fuel combustion. The milling behaviour of 7 woody, herbaceous... Read More about Influence of mill type on densified biomass comminution.

Experiments on torrefied wood pellet: study by gasification and characterization for waste biomass to energy applications (2016)
Journal Article
Rollinson, A., & Williams, O. (2016). Experiments on torrefied wood pellet: study by gasification and characterization for waste biomass to energy applications. Royal Society Open Science, 3, Article 150578. https://doi.org/10.1098/rsos.150578

Samples of torrefied wood pellet produced by low-temperature microwave pyrolysis were tested through a series of experiments relevant to present and near future waste to energy conversion technologies. Operational performance was assessed using a mod... Read More about Experiments on torrefied wood pellet: study by gasification and characterization for waste biomass to energy applications.

Impact of mill type on biomass mill behavior (2015)
Presentation / Conference Contribution
Williams, O., Eastwick, C., Lester, E., Giddings, D., & Lormor, S. Impact of mill type on biomass mill behavior. Presented at 2015 ASABE Annual International Meeting

With increasing use of biomass in pulverized fuel coal fired power stations, the impact of mill type on biomass size and shape is fundamental in optimizing mill and burner performance. The impact of mill type on the energy consumption, particle size... Read More about Impact of mill type on biomass mill behavior.