Will Meredith
@nottingham.ac.uk
University of Nottingham
Scopus Publications
Scopus Publications
Ana Karen Silos-Llamas, Hanifrahmawan Sudibyo, Virginia Hernández-Montoya, Will Meredith, and Gabriela Durán-Jiménez
Elsevier BV
Fatih Güleç, Jude A. Okolie, Peter T. Clough, Ahmet Erdogan, Will Meredith, and Colin E. Snape
Elsevier BV
Sherif Farouk, Ahmed Khairy, Amr M. Shehata, Clement N. Uguna, Tamer El Sheennawy, Ahmad Salama, Khaled Al-Kahtany, and Will Meredith
Elsevier BV
Fatih Güleç, Hanifrahmawan Sudibyo, Emily T. Kostas, Orla Williams, Abby Samson, Will Meredith, and Edward Lester
Elsevier BV
Ahmed Khairy, Waleed Sh. El Diasty, Clement N. Uguna, Kenneth E. Peters, Christopher H. Vane, Colin E. Snape, and Will Meredith
Elsevier BV
Fatih Güleç, Will Meredith, and Colin E. Snape
Elsevier BV
Nidia Diaz Perez, Christian Lindfors, Lambertus A. M. van den Broek, Jacinta van der Putten, William Meredith, and John Robinson
Springer Science and Business Media LLC
Nidia Diaz Perez, Christian Lindfors, Lambertus A. M. van den Broek, Jacinta van der Putten, William Meredith, and John Robinson
Springer Science and Business Media LLC
AbstractA total of 120,000 tonnes per year of crop waste from contaminated land has been used as a feedstock for anaerobic digestion (AD). This produces only around 20% of biogas from the total crop and results in a large amount of digestate with heavy metal content. This crop digestate was analyzed across a calendar year to identify the variation in composition, and any potential high-value components that could be targeted for recovery. The chemical characterization revealed that approximately 65% of this residual waste is lignocellulosic material (20% hemicellulose, 24% cellulose, 24% lignin) and about 10% is ash, with no observable difference across the seasons. Three different pyrolysis technologies were studied with the same crop digestate as alternative route to maximize the value of this solid residue by transforming this lignocellulosic material into further bio-based products. Slow pyrolysis at operating temperatures between 355 and 530 °C resulted in bio-oil yields of 35–46% wt, fast pyrolysis at 460–560 °C produced 36–40% wt, and microwave pyrolysis using a power input of 500 and 700 W generated 8–27% wt from the digestate. Chemical compounds found in these bio-oils were categorized into seven chemical groups: acids, aldehydes and ketones, alcohols, furans, sugars, phenolics, and others. This analytical study opens other scenarios to explore the upgrading of these pyrolytic bio-oils for green product generation from the same waste. Graphical Abstract
Finlay Kenneth, Catherine F.H. Joniver, William Meredith, and Jessica M.M. Adams
Informa UK Limited
Abubakar M. Haruna, Will Meredith, and Colin E. Snape
Elsevier BV
A. Khairy, W. Sh. El Diasty, K.E. Peters, and W. Meredith
Elsevier BV
Wei Li, Lee A. Stevens, Will Meredith, Clement N. Uguna, Christopher H. Vane, Bo Zhang, Andrew D. Carr, Dingye Zheng, and Colin E. Snape
Elsevier BV
Marta Crispo, Duncan D. Cameron, Will Meredith, Aaron Eveleigh, Nicos Ladommatos, Ondřej Mašek, and Jill L. Edmondson
Elsevier BV
Soils hold three quarters of the total organic carbon (OC) stock in terrestrial ecosystems and yet we fundamentally lack detailed mechanistic understanding of the turnover of major soil OC pools. Black carbon (BC), the product of the incomplete combustion of fossil fuels and biomass, is ubiquitous in soils globally. Although BC is a major soil carbon pool, its effects on the global carbon cycle have not yet been resolved. Soil BC represents a large stable carbon pool turning over on geological timescales, but research suggests it can alter soil biogeochemical cycling including that of soil OC. Here, we established two soil microcosm experiments: experiment one added 13C OC to soil with and without added BC (soot or biochar) to investigate whether it suppresses OC mineralisation; experiment two added 13C BC (soot) to soil to establish whether it is mineralised in soil over a short timescale. Gases were sampled over six-months and analysed using isotope ratio mass spectrometry. In experiment one we found that the efflux of 13C OC from soil decreased over time, but the addition of soot to soil significantly reduced the mineralisation of OC from 32% of the total supplied without soot to 14% of the total supplied with soot. In contrast, there was not a significant difference after the addition of biochar in the flux of 13C from the OC added to the soil. In experiment two, we found that the efflux 13C from soil with added 13C soot significantly differed from the control, but this efflux declined over time. There was a cumulative loss of 0.17% 13C from soot over the experiment. These experimental results represent a step-change in understanding the influence of BC continuum on carbon dynamics, which has major consequences for the way we monitor and manage soils for carbon sequestration in future.
Marta Crispo, Miriam C. Dobson, Roscoe S. Blevins, Will Meredith, Janice A. Lake, and Jill L. Edmondson
Elsevier BV
Urban horticulture (UH) has been proposed as a solution to increase urban sustainability, but the potential risks to human health due to potentially elevated soil heavy metals and metalloids (HM) concentrations represent a major constraint for UH expansion. Here we provide the first UK-wide assessment of soil HM concentrations (total and bioavailable) in UH soils and the factors influencing their bioavailability to crops. Soils from 200 allotments across ten cities in the UK were collected and analysed for HM concentrations, black carbon (BC) and organic carbon (OC) concentrations, pH and texture. We found that although HM are widespread across UK UH soils, most concentrations fell below the respective UK soil screening values (C4SLs): 99 % Cr; 98 % As, Cd, Ni; 95 % Cu; 52 % Zn. However, 83 % of Pb concentrations exceeded C4SL, but only 3.5 % were above Pb national background concentration of 820 mg kg-1. The bioavailable HM concentrations represent a small fraction (0.01-1.8 %) of the total concentrations even for those soils that exceeded C4SLs. There was a significant positive relationship between both total and bioavailable HM and soil BC and OC concentrations. This suggest that while contributing to the accumulation of HM concentrations in UH soils, BC and OC may also provide a biding surface for the bioavailable HM concentrations contributing to their immobilisation. These findings have implications for both management of the risk to human health associated with UH growing in urban soils and with management of UH soil. There is a clear need to understand the mechanisms driving soil-to-crop HM transfer in UH to improve potentially restrictive C4SL (e.g. Pb) especially as public demand for UH land is growing. In addition, the UH community would benefit from education programs promoting soil management practices that reduce the risk of HM exposure - particularly in those plots where C4SLs were exceeded.
Kelden Pehr, Rose Bisquera, Andrew N. Bishop, Frantz Ossa Ossa, William Meredith, Andrey Bekker, and Gordon D. Love
Mary Ann Liebert Inc
The likelihood of finding pristine molecular biosignatures preserved in Earth's oldest rocks or on other planetary bodies is low, and new approaches are needed to assess the origins of highly altered and recalcitrant organic matter. In this study, we aim to understand the distributions and systematics of preservation of ancient polycyclic aromatic hydrocarbons (PAHs), as both free hydrocarbons and bound within insoluble macromolecules. We report the distributions of bound PAHs generated by catalytic hydropyrolysis from ancient biogenic kerogens and from insoluble organic matter (IOM) in high-temperature carbonaceous residues from pyrobitumens and synthetic coke. For biogenic kerogens, the degree of thermal maturity exerts the primary control on the preservation and distributions of the major five-ring and six-ring PAH compounds. This holds for both Precambrian and Phanerozoic rocks, thus source variation in primary biogenic organic matter inputs does not exert the major control on bound PAH. The IOM samples, predominantly residues from hydrocarbon cracking at high temperatures, preserve a bound PAH profile significantly distinct from ancient biogenic kerogens and characterized by an absence of perylene and higher abundance of large-ring condensed PAHs. Covalently bound PAH profiles offer promise as "last resort" molecular biosignatures for aiding the astrobiological search for ancient life.
Gabriela Durán-Jiménez, Emily T. Kostas, Lee A. Stevens, Will Meredith, Maria Erans, Virginia Hernández-Montoya, Adam Buttress, Clement N. Uguna, and Eleanor Binner
Elsevier BV
This study has demonstrated, for the first time, a simple, fast and flexible microwave processing method for the simultaneous preparation of bio-products (bio-oil, bio-gas and biochar) using a methodology that avoids any form of catalyst or chemical activation. The dielectric properties of biomass and physicochemical characterisation such as TGA, elemental and proximate analysis, XRD, SEM/EDX and textural properties, showed that 8 kJ g-1 of microwave energy can produce superior biochars for applications in CO2 capture. The maximum CO2 uptake capacity for biochar produced was 2.5 mmol g-1 and 2.0 mmol g-1 at 0 and 25 °C and 1 bar, which and also exhibited high gas selectivity compared with N2, fast kinetics of adsorption (<10 min) and desirable reusability (>95%) after 20 cycles. GC-MS analysis of generated bio-oil products revealed that higher microwave energies (>8 kJ g-1) significantly enhanced the amount of bio-oil produced (39%) and specifically the formation of levoglucosan, furfural and phenolics compounds, and bio-gas analysis identified trace levels of H2 and CH4. The results from this study confirm a green, inexpensive and efficient approach for biomass valorisation which can easily be embedded within bio-refinery process, and also demonstrates the potential of biochars for post-combustion CO2 uptake.
Wei Li, Lee A. Stevens, Clement N. Uguna, Christopher H. Vane, Will Meredith, Ling Tang, Qianwen Li, and Colin E. Snape
Elsevier BV
Thomas Stanton, Paul Kay, Matthew Johnson, Faith Ka Shun Chan, Rachel L. Gomes, Jennifer Hughes, William Meredith, Harriet G. Orr, Colin E. Snape, Mark Taylor,et al.
Wiley
Cristian Bernabé Arenas, William Meredith, Collin Edward Snape, Xiomar Gómez, José Francisco González, and Elia Judith Martinez
Springer Science and Business Media LLC
The effect of char addition on the digestion of animal by-products was evaluated as a way for enhancing the performance of the process. Two different types of carbonaceous materials were tested as carbon conductive elements to improve biological treatment. One was derived from a torrefaction process intended for increasing the energy density of lignocellulosic biomass, and the other was obtained from a hydrothermal carbonisation process. In this research, batch digestion systems of animal waste samples were evaluated at a volatile solid (VS) ratio of 1:1 inoculum–substrate (where the content of the substrate in the system was 1.69 ± 0.2 g). The system reported a baseline methane yield of 380 L CH 4 kg VS -1 which increased on average to 470 L CH 4 kg VS -1 following to the addition of char. The presence of char allowed a faster degradation of the lipid and protein material, reducing inhibitory interactions. The use of Fourier transformed infrared spectroscopy was applied for elucidating the predetermination of the degradation process and bring an insight into the greater degradation potential attained when carbon materials are used for enhancing microbial performance.
Fatih Güleç, Will Meredith, Cheng-Gong Sun, and Colin E. Snape
Elsevier BV
Abstract Fluid Catalytic Cracking (FCC) units are responsible for roughly 25% of CO2 emissions from oil refineries, which themselves account for 4–6% of total global CO2 emissions. Although post- and oxy-combustion technologies have been proposed for CO2 capture in FCC, Chemical Looping Combustion (CLC) may also be a potential approach that has lower energy consumption. An equilibrium catalyst (ECat) was first modified with oxidised oxygen carriers (CuO, Co3O4, Mn2O3) using wet-impregnation, and their reduced states (Cu, CoO, Mn3O4, MnO) were generated by hydrogen reduction. To demonstrate that the impregnated reduced oxygen carriers had no significant negative effects on cracking, the prepared catalysts were used to crack n-hexadecane using the standard FCC microactivity test (ASTM D3907-13). The CLC behaviour of coke deposited on the reduced oxygen carrier impregnated ECats, was investigated with the stoichiometrically required amount of oxidised oxygen carrier impregnated ECat in lab scale fixed-bed and fluidised-bed reactors equipped with an online mass spectrometer to monitor CO2 release. Although the conversion and liquid to gas ratio were largely unaffected, coke selectivity did increase with the impregnation of reduced oxygen carriers. However, this increase is mostly attributed to solvent extractable coke. It is possible to reach about 90 vol% combustion efficiency of the coke deposited on ECat using mechanically mixed with CuO and Mn2O3, but the regeneration temperature required, 800 °C, is considerably higher than that under typical regenerator conditions of 650–750 °C for 30–60 min. However, relatively high combustion efficiencies of greater than 94 vol% of the coke deposited on reduced Cu and Mn3O4 impregnated ECat were achieved with the stoichiometrically required amount of CuO and Mn2O3 impregnated ECat at 750 °C for 45 min., close to conventional FCC regenerator conditions.
Emily T. Kostas, Gabriela Durán-Jiménez, Benjamin J. Shepherd, Will Meredith, Lee A. Stevens, Orla S.A. Williams, Gary J. Lye, and John P. Robinson
Elsevier BV
Abstract 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 with microwaves for the production of bio-char and bio-oil. It was found that the energy requirement needed to pyrolyse up to 80% of the olive pomace was as low as 3.6 kJ/g and bio-oil yields up to 30% were produced. Microwave power did not influence the overall yields or the chemical composition of the obtained bio-oils, but did alter the textural properties of the generated bio-chars and their ability to remove methylene blue dye. Optimum processing conditions were found to be within the 3.6 kJ/g energy requirement with a microwave power of 200 W and processing time of 180 sec. These conditions produced a bio-oil fraction containing mainly acetic acid (71.9%) and a bio-char with a surface area of 392.3 m2/g, micropore volume of 0.15 cm3/g and a methylene blue removal efficiency of 40 qMB mg/g. The results acquired from this study reveal the superiority of microwave heating in a pyrolysis system and highlight a novel and prospective route for added value recovery from natural waste resources like olive pomace.
Fatih Güleç, Will Meredith, and Colin E. Snape
Frontiers Media SA
Heavy industries including cement, iron and steel, oil refining, and petrochemicals are collectively responsible for about 22% of global CO2 emissions. Among these industries, oil refineries account for 4–6%, of which typically 25–35% arise from the regenerators in Fluid Catalytic Cracking (FCC) units. This article reviews the progress in applying CO2 capture technologies to FCC units. Post combustion and oxyfuel combustion have been investigated to mitigate CO2 emissions in FCC and, more recently, Chemical Looping Combustion (CLC) has received attention. Post combustion capture can readily be deployed to the flue gas in FCC units and oxyfuel combustion, which requires air separation has been investigated in a pilot-scale unit by Petrobras (Brazil). However, in comparison, CLC offers considerably lower energy penalties. The applicability of CLC for FCC has also been experimentally investigated at a lab-scale. As a result, the studies demonstrated highly promising CO2 capture capacities for FCC with the application of post combustion (85–90%), oxyfuel combustion (90–100%) and CLC (90–96%). Therefore, the method having lowest energy penalty and CO2 avoided cost is highly important for the next generation of FCC units to optimize CO2 capture. The energy penalty was calculated as 3.1–4.2 GJ/t CO2 with an avoiding cost of 75–110 €/t CO2 for the application of post combustion capture to FCC. However, the application of oxyfuel combustion provided lower energy penalty of 1.8–2.5 GJ/t CO2, and lower CO2 avoided cost of 55–85 €/t CO2. More recently, lab-scale experiments demonstrated that the application of CLC to FCC demonstrate significant progress with an indicative much lower energy penalty of ca. 0.2 GJ/t CO2.
W. Meredith, C. N. Uguna, C. E. Snape, A. D. Carr, and I. C. Scotchman
Geological Society of London
AbstractThe Elgin–Franklin complex contains gas condensates in Upper Jurassic reservoirs in the North Sea Central Graben. Upper parts of the reservoirs contain bitumens, which previous studies have suggested were formed by the thermal cracking of oil as the reservoirs experienced temperatures of >150°C during rapid Plio-Pleistocene subsidence. Bitumen-stained cores contaminated by oil-based drilling muds have been analysed by hydropyrolysis. Asphaltene-bound aliphatic hydrocarbon fractions were dominated by n-hexadecane and n-octadecane originating from fatty acid additives in the muds. Uncontaminated asphaltene-bound aromatic hydrocarbon fractions, however, contained a PAH distribution very similar to normal North Sea oils, suggesting that the bitumens may not have been derived from oil cracking.1D basin models of well 29/5b-6 and a pseudo-well east of the Elgin–Franklin complex utilize a thermal history derived from the basin's rifting and subsidence histories, combined with the conservation of energy currently not contained in the thermal histories. Vitrinite reflectance values predicted by the conventional kinetic models do not match the measured data. Using the pressure-dependent PresRo® model, however, a good match was achieved between observed and measured data. The predicted petroleum generation is combined with published diagenetic cement data from the Elgin and Franklin fields to produce a composite model for petroleum generation, diagenetic cement and bitumen formation.