• Methods for the Treatment of Cattle Manure—A Review

      Font-Palma, Carolina; orcid: 0000-0003-1416-4244; email: c.fontpalma@chester.ac.uk (MDPI, 2019-05-15)
      Environmental concerns, caused by greenhouse gases released to the atmosphere and overrunning of nutrients and pathogens to water bodies, have led to reducing direct spread onto the land of cattle manure. In addition, this practice can be a source of water and air pollution and toxicity to life by the release of undesirable heavy metals. Looking at the current practices, it is evident that most farms separate solids for recycling purposes, store slurries in large lagoons or use anaerobic digestion to produce biogas. The review explores the potential for cattle manure as an energy source due to its relatively large calorific value (HHV of 8.7–18.7 MJ/kg dry basis). This property is beneficial for thermochemical conversion processes, such as gasification and pyrolysis. This study also reviews the potential for upgrading biogas for transportation and heating use. This review discusses current cattle manure management technologies—biological treatment and thermochemical conversion processes—and the diverse physical and chemical properties due to the differences in farm practices.
    • Evaluation of the performance and economic viability of a novel low temperature carbon capture process

      Wilson, Paul; Lychnos, George; Clements, Alastair; Michailos, Stavros; Font-Palma, Carolina; Diego, Maria E.; Pourkashanian, Mohamed; Howe, Joe; PMW Technology Ltd; University of Sheffield; University of Chester (Elsevier, 2019-04-22)
      A novel Advanced Cryogenic Carbon Capture (A3C) process is being developed using low cost but high intensity heat transfer to achieve high CO2 capture efficiencies with a much reduced energy consumption and process equipment size. These characteristics, along with the purity of CO2 product and absence of process chemicals, offer the potential for application across a range of sectors. This work presents a techno-economic evaluation for applications ranging from 3% to 35%vol. CO2 content. The A3C process is evaluated against an amine-based CO2 capture process for three applications; an oil-fired boiler, a combined cycle gas turbine (CCGT) and a biogas upgrading plant. The A3C process has shown a modest life cost advantage over the mature MEA technology for the larger selected applications, and substantially lower costs in the smaller biogas application. Enhanced energy recovery and optimization offer significant opportunities for further reductions in cost.
    • Promises and Challenges of Growing Microalgae in Wastewater

      Osundeko, Olumayowa; Ansolia, Preeti; Kumar Gupta, Sanjay; Bag, Pushan; Bajhaiya, Amit K.; University of Manchester (Springer, 2019-01-22)
      Microalgae have been theoretically described as a sustainable feedstock for biofuel production. However, there are still some concerns and obstacles that need to be overcome in order to translate the theoretical promise into commercial and economic success. These obstacles include a high requirement for nutrients and sustainable water source and the identification of affordable cultivation conditions. It has been suggested that growing microalgae in wastewater can potentially offset some of these obstacles. Microalgae can perform a dual role for remediation of nutrient pollutants and biomass production when grown in wastewater. However, there are huge challenges to overcome before this route can be exploited in an economically and environmentally sustainable manner. In the present chapter, the potentials and challenges of growing microalgae in wastewater and its future implications are discussed in detail.
    • Towards sustainable methanol from industrial CO2 sources

      Douven, Sigrid; Benkoussas, Hana; Font Palma, Carolina; Leonard, Gregoire; University of Liege; University of Chester (Walter de Gruyter GmbH, 2019)
      This chapter discusses the opportunity of using CO2 from industrial sources to produce sustainable methanol. Some important industrial sectors that could be seen as potential sources of CO2 are reviewed: ammonia, steel, ethanol, ethylene, natural gas, cement and power industries. In most cases, despite a promising potential for CO2 re-use, only few projects have been identified and methanol production from CO2 is still marginal. A model for the CO2-to-methanol process is presented based on CO2-rich gas coming from ammonia production process. This model takes into account the different steps from the CO2 capture to the methanol purification, and heat integration is performed in order to determine the reduction of heat consumption achievable for the global process. Even if the economic relevance of the CO2 re-use into methanol still has to be qualified, it offers an estimation of the process efficiency.
    • The Interplay Between Cholesterol Metabolism and Intrinsic Ageing

      Mc Auley, Mark; University of Chester (SpringerLink, 2018-12-31)
      The last few decades have witnessed remarkable progress in our understanding of ageing. From an evolutionary standpoint it is generally accepted that ageing is a non-adaptive process which is underscored by a decrease in the force of natural selection with time. From a mechanistic perspective ageing is characterized by a wide variety of cellular mechanisms, including processes such as cellular senescence, telomere attrition, oxidative damage, molecular chaperone activity, and the regulation of biochemical pathways by sirtuins. These biological findings have been accompanied by an unrelenting rise in both life expectancy and the number of older people globally. However, despite age being recognized demographically as a risk factor for healthspan, the processes associated with ageing are routinely overlooked in disease mechanisms. Thus, a central goal of biogerontology is to understand how diseases such as cardiovascular disease (CVD) are shaped by ageing. This challenge cannot be ignored because CVD is the main cause of morbidity in older people. A worthwhile way to examine how ageing intersects with CVD is to consider the effects ageing has on cholesterol metabolism, because dysregualted cholesterol metabolism is the key factor which underpins the pathology of CVD. The aim of this chapter is to outline a hypothesis which accounts for how ageing intersects with intracellular cholesterol metabolism. Moreover, we discuss the implications of this relationship for the onset of disease in the 'oldest old' (individuals ≥85 years of age). We conclude the chapter by discussing the important role mathematical modelling has to play in improving our understanding of cholesterol metabolism and ageing.
    • Disrupting folate metabolism reduces the capacity of bacteria in exponential growth to develop persisters to antibiotics

      Morgan, Jasmine; Smith, Matthew; Mc Auley, Mark; Salcedo-Sora, Enrique; Edge Hill University; Liverpool Hope University; University of Chester (Microbiology Society, 2018-11-01)
      Bacteria can survive high doses of antibiotics through stochastic phenotypic diversification. We present initial evidence that folate metabolism could be involved with the formation of persisters. The aberrant expression of the folate enzyme gene fau seems to reduce the incidence of persisters to antibiotics. Folate-impaired bacteria had a lower generation rate for persisters to the antibiotics ampicillin and ofloxacin. Persister bacteria were detectable from the outset of the exponential growth phase in the complex media. Gene expression analyses tentatively showed distinctive profiles in exponential growth at times when bacteria persisters were observed. Levels of persisters were assessed in bacteria with altered, genetically and pharmacologically, folate metabolism. This work shows that by disrupting folate biosynthesis and usage, bacterial tolerance to antibiotics seems to be diminished. Based on these findings there is a possibility that bacteriostatic antibiotics such as anti-folates could have a role to play in clinical settings where the incidence of antibiotic persisters seems to drive recalcitrant infections.
    • Evaluation of the Performance and Economic Viability of a Novel Low Temperature Carbon Capture Process

      Lychnos, George; Clements, Alastair; Willson, Paul; Font-Palma, Carolina; Diego, Maria Elena; Pourkashanian, Mohamed; Howe, Joseph; PMW Technology Limited; University of Sheffield; University of Chester (SSRN, 2018-10)
      A novel Advanced Cryogenic Carbon Capture (A3C) process is being developed due to its potential to achieve high CO2 capture efficiencies using low cost but high intensity heat transfer to deliver a much reduced energy consumption and process equipment size. These characteristics, along with the absence of process chemicals, offer the potential for application across a range of sectors. This work presents a techno-economic evaluation for applications ranging from 3% to 30% CO2 content.
    • Experimental Exploration of CO2 Capture Using a Cryogenic Moving Packed Bed

      Cann, David; Willson, Paul; Font-Palma, Carolina; University of Chester; PMW Technology Ltd; University of Chester (SSRN, 2018-10)
      This study examines a novel cryogenic post-combustion capture process, based on a moving bed of cold beads to freeze CO2 out of a flue gas, and this paper presents the first steps in experimental work. The preliminary experiments included the test of fluidization of bed material, if the flow rate of bed material can be kept constant in and out of the column and the estimation of heat transfer coefficient. The obtained results are encouraging for the running of the rig at cryogenic conditions.
    • The role of DNA methylation in ageing and cancer

      Morgan, Amy; Davies, Trevor J.; Mc Auley, Mark T.; University of Chester (Cambridge University Press, 2018-04-30)
      The aim of the present review paper is to survey the literature related to DNA methylation, and its association with cancer and ageing. The review will outline the key factors, including diet, which modulate DNA methylation. Our rationale for conducting this review is that ageing and diseases, including cancer, are often accompanied by aberrant DNA methylation, a key epigenetic process, which is crucial to the regulation of gene expression. Significantly, it has been observed that with age and certain disease states, DNA methylation status can become disrupted. For instance, a broad array of cancers are associated with promoter-specific hypermethylation and concomitant gene silencing. This review highlights that hypermethylation, and gene silencing, of the EN1 gene promoter, a crucial homeobox gene, has been detected in various forms of cancer. This has led to this region being proposed as a potential biomarker for diseases such as cancer. We conclude the review by describing a recently developed novel electrochemical method that can be used to quantify the level of methylation within the EN1 promoter and emphasise the growing trend in the use of electrochemical techniques for the detection of aberrant DNA methylation.
    • Prospects for petcoke utilization with CO 2 capture in Mexico

      Font Palma, Carolina; Gonzalez Diaz, Abigail; University of Chester; Instituto Nacional de Electricidad y Energías Limpias (INEEL) (Elsevier, 2018-01-31)
      This paper evaluates the introduction of carbon capture and storage (CCS) to Mexico. The gasification technology is presented as a potential alternative to be applied into refinery plants due to high petcoke production. Although economic aspects, such as fuel price and selling CO2, are important in the selection of CCS alternatives, there are other limitations, i.e. water availability and space. In March 2014, Mexico launched its CCS technological roadmap. However, an evaluation of the installation of new CO2-capture ready power plants was not considered. For that reason, this study could be useful to create a technology roadmap that includes the design of CO2 capture plants into refineries and how they will have to operate for CO2 emissions reduction, and taking advantage that most of refineries and petrochemical plants are close to oil fields for enhanced oil recovery (EOR). Integrated gasification combined cycle (IGCC) with CCS was chosen in this paper for power generation using petcoke as feedstock. The emissions of CO2 in kg/kWh could be reduced by 68%.
    • The role of Mathematical Modelling in understanding Aging

      Mc Auley, Mark T.; Morgan, Amy; Mooney, Kathleen; University of Chester, Edgehill University (CRC Press, 2017-10-25)
      Mathematical models have played key roles in developing our understanding of aging. The first pioneering mathematical models evaluated aging from an evolutionary perspective, generating meaningful insights into why aging occurs and laid the foundations for our current understanding of aging. More recently mathematical models have been used to gain a deeper understanding of the intracellular mechanisms associated with intrinsic aging. This chapter will outline what mathematical modelling is, and the advantages it has over more conventional approaches used in biogerontology. The steps involved in assembling a model will also be described and the leading theoretical frameworks underpinning them will be outlined. Moreover, we discuss in detail a variety of aging focused mechanistic mathematical models which have been developed in recent years. The chapter concludes by challenging the community to develop a unified mechanistic mathematical model which can be used to examine aging in a more integrated fashion.
    • Part-load performance of direct-firing and co-firing of coal and biomass in a power generation system integrated with a CO2 capture and compression system

      Ali, Usman; Akram, Muhammad; Font Palma, Carolina; Ingham, Derek B.; Pourkashanian, Mohamed; University of Sheffield; University of Chester; University of Engineering and Technology (Elsevier, 2017-09-18)
      Bioenergy with Carbon Capture and Storage (BECCS) is recognised as a key technology to mitigate CO2 emissions and achieve stringent climate targets due to its potential for negative emissions. However, the cost for its deployment is expected to be higher than for fossil-based power plants with CCS. To help in the transition to fully replace fossil fuels, co-firing of coal and biomass provide a less expensive means. Therefore, this work examines the co-firing at various levels in a pulverised supercritical power plant with post-combustion CO2 capture, using a fully integrated model developed in Aspen Plus. Co-firing offers flexibility in terms of the biomass resources needed. This work also investigates flexibility within operation. As a result, the performance of the power plant at various part-loads (40%, 60% and 80%) is studied and compared to the baseline at 100%, using a constant fuel flowrate. It was found that the net power output and net efficiency decrease when the biomass fraction increases for constant heat input and constant fuel flow rate cases. At constant heat input, more fuel is required as the biomass fraction is increased; whilst at constant fuel input, derating occurs, e.g. 30% derating of the power output capacity at firing 100% biomass compared to 100% coal. Co-firing of coal and biomass resulted in substantial power derating at each part-load operation.
    • Comparative Potential of Natural Gas, Coal and Biomass Fired Power Plant with Post - combustion CO2 Capture and Compression

      Ali, Usman; Font Palma, Carolina; Akram, Muhammad; Agbonghae, Elvis O.; Ingham, Derek B.; Pourkashanian, Mohamed; University of Sheffield, University of Chester, Nigerian National Petroleum Corporation (Elsevier, 2017-06-07)
      The application of carbon capture and storage (CCS) and carbon neutral techniques should be adopted to reduce the CO2 emissions from power generation systems. These environmental concerns have renewed interest towards the use of biomass as an alternative to fossil fuels. This study investigates the comparative potential of different power generation systems, including NGCC with and without exhaust gas recirculation (EGR), pulverised supercritical coal and biomass fired power plants for constant heat input and constant fuel flowrate cases. The modelling of all the power plant cases is realized in Aspen Plus at the gross power output of 800 MWe and integrated with a MEA-based CO2 capture plant and a CO2 compression unit. Full-scale detailed modelling of integrated power plant with a CO2 capture and compression system for biomass fuel for two different cases is reported and compared with the conventional ones. The process performance, in terms of efficiency, emissions and potential losses for all the cases, is analysed. In conclusion, NGCC and NGCC with EGR integrated with CO2 capture and compression results in higher net efficiency and least efficiency penalty reduction. Further, coal and biomass fired power plants integrated with CO2 capture and compression results in higher specific CO2 capture and the least specific losses per unit of the CO2 captured. Furthermore, biomass with CO2 capture and compression results in negative emissions.
    • LDL-C levels in older people: Cholesterol Homeostasis and the Free Radical Theory of Ageing Converge

      Mc Auley, Mark T.; Mooney, Kathleen M.; Univeristy of Chester; Edge Hill University (Elsevier, 2017-05-17)
      The cardiovascular disease (CVD) risk factor, low density lipoprotein cholesterol (LDL-C) increases with age, up until the midpoint of life in males and females. However, LDL-C can decrease with age in older men and women. Intriguingly, a recent systematic review also revealed an inverse association between LDL-C levels and cardiovascular mortality in older people; low levels of LDL-C were associated with reduced risk of mortality. Such findings are puzzling and require a biological explanation. In this paper a hypothesis is proposed to explain these observations. We hypothesize that the free radical theory of ageing (FRTA) together with disrupted cholesterol homeostasis can account for these observations. Based on this hypothesis, dysregulated hepatic cholesterol homeostasis in older people is characterised by two distinct metabolic states. The first state accounts for an older person who has elevated plasma LDL-C. This state is underpinned by the FRTA which suggests there is a decrease in cellular antioxidant capacity with age. This deficiency enables hepatic reactive oxidative species (ROS) to induce the total activation of HMG-CoA reductase, the key rate limiting enzyme in cholesterol biosynthesis. An increase in cholesterol synthesis elicits a corresponding rise in LDL-C, due to the downregulation of LDL receptor synthesis, and increased production of very low density lipoprotein cholesterol (VLDL-C). In the second state of dysregulation, ROS also trigger the total activation of HMG-CoA reductase. However, due to an age associated decrease in the activity of cholesterol-esterifying enzyme, acyl CoA: cholesterol acyltransferase, there is restricted conversion of excess free cholesterol (FC) to cholesterol esters. Consequently, the secretion of VLDL-C drops, and there is a corresponding decrease in LDL-C. As intracellular levels of FC accumulate, this state progresses to a pathophysiological condition akin to nonalcoholic fatty liver disease. It is our conjecture this deleterious state has the potential to account for the inverse association between LDL-C level and CVD risk observed in older people.
    • Benchmarking of a micro gas turbine model integrated with post-combustion CO2 capture

      Usman, Ali; Font Palma, Carolina; Nikpey Somehsaraei, Homam; Mansouri Majoumerd, Mohammad; Akram, Muhammad; Finney, Karen N.; Best, Thom; Mohd Said, Nassya B.; Assadi, Mohsen; Pourkashanian, Mohamed; University of Sheffield; University of Chester; University of Stavanger; International Research Institute of Stavanger; University of Leeds (Elsevier, 2017-03-19)
      The deployment of post-combustion CO2 capture on large-scale gas-fired power plants is currently progressing, hence the integration of the power and capture plants requires a good understanding of operational requirements and limitations to support this effort. This article aims to assist research in this area, by studying a micro gas turbine (MGT) integrated with an amine-based post-combustion CO2 capture unit. Both processes were simulated using two different software tools –IPSEpro and Aspen Hysys, and validated against experimental tests. The two MGT models were benchmarked at the nominal condition, and then extended to part-loads (50 and 80 kWe), prior to their integration with the capture plant at flue gas CO2 concentrations between 5 and 10 mol%. Further, the performance of the MGT and capture plant when gas turbine exhaust gases were recirculated was assessed. Exhaust gas recirculation increases the CO2 concentration, and reduces the exhaust gas flowrate and specific reboiler duty. The benchmarking of the two models revealed that the IPSEpro model can be easily adapted to new MGT cycle modifications since turbine temperatures and rotational speeds respond to reaching temperature limits; whilst a detailed rate-based approach for the capture plant in Hysys resulted in closely aligned simulation results with experimental data.
    • Modelling the molecular mechanisms of ageing

      Mc Auley, Mark T.; Martinez Guimera, Alvaro; Hodgson, David; McDonald, Neil; Mooney, Kathleen M.; Morgan, Amy; Proctor, Carole; University of Chester; Edgehill University; Newcastle University (Portland Press, 2017-02-23)
      The ageing process is driven at the cellular level by random molecular damage which slowly accumulates with age. Although cells possess mechanisms to repair or remove damage, they are not 100% efficient and their efficiency declines with age. There are many molecular mechanisms involved and exogenous factors such as stress also contribute to the ageing process. The complexity of the ageing process has stimulated the use of computational modelling in order to increase our understanding of the system, test hypotheses and make testable predictions. As many different mechanisms are involved, a wide range of models have been developed. This paper gives an overview of the types of models that have been developed, the range of tools used, modelling standards, and discusses many specific examples of models which have been grouped according to the main mechanisms that they address. We conclude by discussing the opportunities and challenges for future modelling in this field.
    • Combined heat and power from the intermediate pyrolysis of biomass materials: performance, economics and environmental impact

      Yang, Yang; Brammer, John; Wright, Daniel; Scott, Jim; Serrano, Clara; Bridgwater, Tony; Aston University; University of Chester (Elsevier, 2017-02-10)
      Combined heat and power from the intermediate pyrolysis of biomass materials offers flexible, on demand renewable energy with some significant advantages over other renewable routes. To maximize the deployment of this technology an understanding of the dynamics and sensitivities of such a system is required. In the present work the system performance, economics and life-cycle environmental impact is analysed with the aid of the process simulation software Aspen Plus. Under the base conditions for the UK, such schemes are not currently economically competitive with energy and char products produced from conventional means. However, under certain scenarios as modelled using a sensitivity analysis this technology can compete and can therefore potentially contribute to the energy and resource sustainability of the economy, particularly in on-site applications with low-value waste feedstocks. The major areas for potential performance improvement are in reactor cost reductions, the reliable use of waste feedstocks and a high value end use for the char by-product from pyrolysis.
    • Computational Modelling Folate Metabolism and DNA Methylation: Implications for Understanding Health and Ageing

      Mc Auley, Mark T.; Mooney, Kathleen M.; Salcedo-Sora, J. Enrique; University of Chester; Edge Hill University; Liverpool Hope University (Oxford University Press, 2016-12-21)
      Dietary folates have a key role to play in health as deficiencies in the intake of these B vitamins have been implicated in a wide variety of clinical conditions. The reason for this is folates function as single carbon donors in the synthesis of methionine and nucleotides. Moreover, folates have a vital role to play in the epigenetics of mammalian cells by supplying methyl groups for DNA methylation reactions. Intriguingly, a growing body of experimental evidence suggests DNA methylation status could be a central modulator of the ageing process. This has important health implications because the methylation status of the human genome could be used to infer age-related disease risk. Thus, it is imperative we further our understanding of the processes which underpin DNA methylation and how these intersect with folate metabolism and ageing. The biochemical and molecular mechanisms which underpin these processes are complex. However, computational modelling offers an ideal framework for handling this complexity. A number of computational models have been assembled over the years, but to date no model has represented the full scope of the interaction between the folate cycle and the reactions which govern the DNA methylation cycle. In this review we will discuss several of the models which have been developed to represent these systems. In addition we will present a rationale for developing a combined model of folate metabolism and the DNA methylation cycle.
    • Carbon dioxide rich microbubble acceleration of biogas production in anaerobic digestion

      Al-Mashhadani, Mahmood K. H.; Wilkinson, Stephen J.; Zimmerman, William B. (2016-12-15)
      This paper addresses the use of anaerobic bacteria to convert carbon dioxide to biomethane as part of the biodegradation process of organic waste. The current study utilises gaslift bioreactors with microbubbles generated by fluidic oscillation to strip the methane produced in the gaslift bioreactor. Removal of methane makes its formation thermodynamically more favourable. In addition, intermittent sparging of microbubbles can prevent thermal stratification, maintain uniformity of the pH and increase the intimate contact between the feed and microbial culture with lower energy requirements than traditional mixing. A gaslift bioreactor with microbubble sparging has been implemented experimentally, using a range of carrier gas, culminating in pure carbon dioxide, in the anaerobic digestion process. The results obtained from the experiments show that the methane production rate is approximately doubled with pure carbon dioxide as the carrier gas for intermittent microbubble sparging.
    • Investigating Cholesterol Metabolism and Ageing Using a Systems Biology Approach

      Morgan, Amy; Mooney, Kathleen M.; Wilkinson, Stephen J.; Pickles, Neil; Mc Auley, Mark T.; University of Chester (Cambridge University Press, 2016-11-02)
      CVD accounted for 27 % of all deaths in the UK in 2014, and was responsible for 1·7 million hospital admissions in 2013/2014. This condition becomes increasingly prevalent with age, affecting 34·1 and 29·8 % of males and females over 75 years of age respectively in 2011. The dysregulation of cholesterol metabolism with age, often observed as a rise in LDL-cholesterol, has been associated with the pathogenesis of CVD. To compound this problem, it is estimated by 2050, 22 % of the world's population will be over 60 years of age, in culmination with a growing resistance and intolerance to pre-existing cholesterol regulating drugs such as statins. Therefore, it is apparent research into additional therapies for hypercholesterolaemia and CVD prevention is a growing necessity. However, it is also imperative to recognise this complex biological system cannot be studied using a reductionist approach; rather its biological uniqueness necessitates a more integrated methodology, such as that offered by systems biology. In this review, we firstly discuss cholesterol metabolism and how it is affected by diet and the ageing process. Next, we describe therapeutic strategies for hypercholesterolaemia, and finally how the systems biology paradigm can be utilised to investigate how ageing interacts with complex systems such as cholesterol metabolism. We conclude by emphasising the need for nutritionists to work in parallel with the systems biology community, to develop novel approaches to studying cholesterol metabolism and its interaction with ageing.