An amine-based CO2 capture plant could mitigate CO2 emissions from a combined-cycle gas turbine (CCGT) plant, but it would require substantial energy. This investigation tackles this issue by assessing the merits of absorber intercooling (AIC) for a CO2 capture plant under the exhaust gas recirculation (50%EGR) and selective exhaust gas recirculation (70%SEGR) flue gas conditions for a CCGT plant, which, to the best of the authors' knowledge, has not been addressed in previous studies. The findings revealed that the greatest benefits of AIC were observed when the bulge temperature peaked at the center of the absorber under the critical lean loading. At the critical lean loading (mol CO2/mol MEA) of 0.35, 0.34, and 0.28 for baseline, EGR, and SEGR, respectively, installing three intercoolers in the absorber can reduce the bulge temperature by approximately 5-9 degrees C. This results in a 22-29% reduction in specific reboiler duty (SRD) across all configurations. In comparison, at the optimal lean loading of 0.20 across all configurations, the advantages of three intercoolers were limited to approximately 1-2 degrees C reductions in bulge temperature and around 7-9% reductions in SRD.

Residential buildings are among the largest energy consumers worldwide. While energy efficiency standards are critical for reducing consumption, approximately 110 countries currently lack mandatory building energy codes. Furthermore, traditional static assessment methods such as degree-day, often miscalculate actual energy demand, leading to significant uncertainties in system sizing. This study proposes a new, structured and holistic framework, based on a transient TRNSYS model, to evaluate the dynamic energy profiles of a typical residential building in temperate climates. The methodology includes the calculation of high-resolution demand profiles for space heating (SH), space cooling (SC), domestic hot water (DHW), and electrical energy (EE). Dynamic simulation results indicate that SH constitutes the largest share of energy demand (5721 kWh), followed by EE (2265 kWh), DHW (1497 kWh), and SC (594 kWh). These findings highlight the dominant role of heating along with the persistent baseload from electrical appliances. The results also provide valuable insights into energy policy and the design of demand-side management strategies. Consequently, this holistic approach offers a useful reference for architects and engineers when determining appropriate system sizing and integrating renewable energy technologies.

Decarbonisation of critical hard-to-abate industrial sectors such as the iron and steel industry is crucial for meeting climate targets, with chemical absorption carbon capture identified as a key transitional technology. However, its application is hindered by a significant knowledge gap: the absence of publicly available and transparent performance benchmarks using conventional capture systems under elevated CO2 conditions that are representative of industrial process emissions. An experimental performance campaign was conducted on the chemical absorption pilot plant at the Energy Innovation Centre (EIC) in Sheffield, UK. The study established a novel performance baseline across a wide operating envelope for flue gas concentrations ranging from 10 to 25 mol.% CO2, achieving 90% capture efficiency using a 35 wt.% monoethanolamine (MEA) solvent. In addition, a methodology was developed to quantify solvent regeneration energy and its constituent components, complementing a system energy balance for each capture condition. The results provided experimentally validated insight into the relationship between operating conditions, capture performance, and energy demand at elevated CO2 concentrations. The dataset established a robust baseline for conventional packed-bed systems and improved understanding of regeneration energy contributions under industrially relevant conditions. These findings are scalable for application to the design, operation and optimisation of chemical absorption systems in heavy industries and provide a reliable benchmark for future work on advanced solvents, process intensification and scale-up to commercial deployment.

The primary challenge in integrating post-combustion CO2 capture (PCC) with natural gas combined cycle (NGCC) is the significant energy consumption and capital costs. The novelty of this paper lies in proposing for the first time an advanced novel configuration that combines lean vapor compression (LVC) for the PCC plant with the NGCC plant incorporating exhaust gas recirculation (EGR) and selective exhaust gas recirculation (SEGR). The simulation results illustrated that implementing 33 % EGR can increase the CO2 level in exhaust gas from a baseline of 4.2 to 6.3 mol%. In comparison, 53 % SEGR increased the CO2 concentration in the flue gas to 8.8 mol %. Among the different configurations examined, SEGR + LVC achieved the highest energy saving for reboiler duty, which was 14 % compared to the baseline. In contrast, the EGR + LVC recorded the highest enhancement in thermal efficiency by 0.7 % points compared to the reference case. The LVC alone resulted in approximately 0.4 % points improvement in thermal efficiency for all configurations evaluated when the gas turbine loads were reduced from 100 to 60 %. This indicates that LVC is effective under partial loads. Finally, SEGR + LVC results in the greatest cost reduction for the PCC plant equipment, lowering the cost by 26 % compared to the baseline. However, the SEGR has the highest total plant cost and total overnight cost due to additional costs for the CO2 membrane separation system.

Waste generation and energy demand are increasing and both require innovative energy symbiosis strategies to meet climate targets. Traditional waste-to-energy processes rely on incineration, but more efficient and sustainable solutions are needed. The aim of the study is to investigate for the first time the feasibility of generating cooling, heating, power (CCHP), and liquid biomethane from plastics and food waste integrated with carbon capture and storage (CCS). The system, modelled in Aspen Plus, consists of a plasma gasifier (PG), anaerobic digester (AD), combined cycle gas turbine (CCGT), absorption refrigeration cooler (ARC), and biomethane liquefier. Two scenarios were analyzed: (1) a standalone CCHP system and (2) its integration with liquid biomethane production. Each scenario includes a baseline (without CCS), pre-combustion CCS, and post-combustion CCS, both with a 95% CO₂ capture fraction. Utilising 5 kg/s of plastic and 13.97 kg/s of food waste, the system generates net power (29.76–85.67 MW), cooling (2.72–4.04 MW), heating (13.99–27.87 MW), and 43.26 MW of liquid biomethane. The highest energy and exergy efficiencies achieved are 49.44% and 41.20%, with carbon emissions ranging from 0.008 to 0.247 kgCO₂/kg waste. The findings of this novel study highlight the potential of integrating several energy systems for an effective waste management strategy that can contribute to the provision of several energy vectors while the inclusion of CCS ensures that significant emission reduction can be attained.

Due to their outstanding structural, transport and electrical characteristics, nickel foams serve as excellent candidate materials for gas diffusion layers (GDLs) in polymer electrolyte fuel cells (PEFCs). In this work, a new three-dimensional PEFC model was developed to explore the local and global fuel cell performance with nickel foam-based GDLs. The fuel cell operating with nickel foam GDLs was shown to have, due to its superior mass and charge transport properties, higher oxygen and water concentration and current density compared to that operating with the conventional carbon fibre-based GDLs. The results show that the pumping power should be taken into account when optimising the dimensions of the flow channels and as such the net power density must be the criterion for optimisation. The optimal dimensions of the flow channels for the fuel cell operating with nickel foam based GDLs were found to be 0.25 mm for the channel height and 1 mm for the channel width; the maximum net power density with these dimensions was around 0.95 W/cm2 which is two times higher than that operating with carbon fibre based GDLs. All the results have been presented and critically discussed.

An improved predictive numerical index has been developed to predict the tendency of bed agglomeration in fluidized bed boilers. The index was developed based on the melt fraction resulting from the thermodynamic equilibrium model of fuel ash compositions together with SiO2 as the bed material at temperatures ranging from 700 to 900 degrees C. The partial least squares regression (PLSR) coupled with the cross-validation technique is utilized to establish the correlation for the bed agglomeration index, Ia. The improved index, Ia has been validated by experimental observations found in various literature sources. The results obtained using the improved index, Ia demonstrated a significantly higher success rate in predicting the bed agglomeration tendency of biomass fuel ash compared to the other four conventional bed agglomeration indices. In addition, K2O is the main element that accelerates the formation of bed agglomeration in the biomass firing while CaO was found to reduce the tendency of bed agglomeration in the fluidized bed combustion system.

Humanity must decarbonise to prevent climate disaster associated with CO2 and other greenhouse gases. The iron and steel industry contribute significantly to global CO2, with 70 % of integrated steel plant emissions arising from the blast furnace. Green alternatives to blast furnaces are still in development, requiring an intermediate stepping-stone solution to begin the decarbonisation journey. Chemical absorption using amine solvents is a proven carbon capture technology, theoretically ideal for flue gas CO2 concentrations and conditions typical of iron and steel making industrial processes. A representative simulation of the Translational Energy Research Centre (TERC) pilot-scale amine capture plant (ACP) was developed in Aspen Plus V11.0 and identified conditions to minimise the specific reboiler duty (SRD) for representative gases of the iron and steel industry. This work predicted operating conditions and trends when using a monoethanolamine (MEA) solvent concentration of 35 wt% across flue gas CO2 concentrations up to 25 mol% CO2. This work established that optimal L/G and solvent/CO2 ratios for MEA absorption systems can be predicted through knowledge of the flue gas CO2 concentration and the desired capture efficiency of the system alone, without consideration of the volumetric gas flow rate of the system. For flue gas CO2 concentrations of 10 to 25 mol%, optimal L/G ratios of 2.5 to 4.6 and solvent/CO2 ratios of 17.1 to 13.5 were identified to achieve 90 % capture efficiency, with the optimal L/G ratio increasing by approximately 0.7 for each 5 mol% increase of CO2 concentration. Optimal lean solvent loadings ranged from 0.245 to 0.294 molCO2/molMEA, with rich solvent loadings ranging from 0.500 to 0.517 molCO2/molMEA. Solvent capacities proved instrumental in understanding the relationship between optimal solvent flow rate and flue gas CO2 concentration for different capture efficiencies. Temperature profile assessment of absorbing and stripping columns is crucial to optimise the system, as each column exhibits unique operational behaviours, with additional attention given to the cross-heat exchanger. The results illustrate key parameters and considerations for CO2 capture of the iron and steel industry, providing initial setpoint conditions and guidance for optimisation. The developed simulation model can be calibrated to represent other MEA absorption systems.

A novel configuration of the hybrid Power-and-Biomass to Liquids (PBtL) pathway for producing sustainable aviation fuels (SAF) has been developed and assessed from a techno-economic and environmental perspective. The proposed configuration can achieve negative emissions and hence a new bioenergy with carbon capture and storage (BECCS) route is proposed. The amount of CO2 that is captured within the process and that is sent for storage ranges from 0 % to 100 %, defining the various PBtL-CCS scenarios that are evaluated. Mass and energy balances have been established through process modelling in Aspen Plus and validated using data available in the literature. Further, the System Advisor Model (SAM) tool was used to model a dedicated offshore wind farm, based on location specific wind data. Results from the technical assessment have set the foundation for economic and environmental evaluations. The economic evaluation of the proposed SAF production configurations estimates minimum jet fuel selling prices (MJSP) ranging from 0.0651 to 0.0673 pound/MJ, mainly driven by electricity consumption and feedstock cost. Costs for CO2 compression, transport, and storage have a small contribution to the MJSPs of all the proposed scenarios. Global warming potentials range from -105.33 to 13.93 gCO2eq/MJ, with PBtL-CCS scenarios offering negative emissions and aligning with the aviation industry's net-zero ambition for 2050. Water footprints range from 0.52 to 0.40 l/MJ, mainly driven by the water requirements of the alkaline electrolyser and refinery, followed by the wind electricity water footprint. Based on the outputs of the assessments, the resulting SAF could benefit of the support proposed by the UK SAF mandate, which could boost their economic performance by awarding certificates with monetary value. Estimates indicate that the cost of certificates that breakeven the fossil jet fuel price could reduce if negative emissions are also rewarded under this scheme.

This study experimentally evaluates the effects of double-sided microporous layer coated gas diffusion layers, comparing conventional Vulcan black with graphene-based microporous layers. Key properties and fuel cell performance were analysed. The results showed that adding graphene improved the in-plane electrical conductivity and increased the gas permeability compared to Vulcan black. Vulcan black microporous layers promoted a more favourable pore size distribution compared to graphene, featuring significant micropores and mesopores in both single and double-sided coatings, while pure graphene produced fewer micropores and mesopores. Contact angle measurements were consistent across all coatings, indicating that wettability depends more on the polytetrafluoroethylene content than on the carbon type. In-situ fuel cell testing demonstrated that a double-sided layer with Vulcan black facing the catalyst layer and graphene facing the bipolar plate performed best under higher humidity conditions by efficiently expelling excess water through the graphene cracks. Conversely, single-sided Vulcan black coatings performed better in low humidity, as their micropore content retained water effectively for membrane humidification.

The aim of this research is to investigate the effect of the two most important threats to the solar power towers’ (SPT) performance, i.e. aerosols’ density and water scarcity, on the SPT feasibility in arid regions. The study is the first attempt to include the site adapted aerosols effect on the SPT’s reflected irradiance and comprehensively investigate several new configurations aiming at optimizing the performance and associated costs. Results show that the inclusion of this effect causes an Annual Energy Generation (AEG) reduction of up to 9.1%. Further, the water consumption analysis is realized based on four different power cycle cooling options, i.e. wet, dry and two hybrid scenarios. Then, a hybridization with Wind Turbines (WT) is proposed as a potential solution to improve the performance of the SPT. The SPT-WT hybridization has been realized with the assistance of an in-house developed algorithm where key design parameters such as solar multiple, thermal energy storage, SPT and WT capacities have been varied over different ranges. It has been found that the configurations with bigger WT share show clear improvements in the Levelized Cost of Energy (LCOE), water consumption and AEG and that’s only when the TES is excluded. However, this comes with a penalty on the capacity factor (CF) which witnesses considerable decreases. The results of this study provide new important information that can be used in conceptual engineering studies and inform policy making.

Slagging and fouling are the most typical causes of unscheduled solid fuel boiler shutdowns. The CFD-based prediction of the deposit growth and rates, which combine the basic mechanisms of ash particle transport, impaction, sticking, as well as the complex aerodynamics of a boiler, is helpful to optimize the design and operation of boilers. In this study, a dynamic CFD model, which contains the molten fraction based sticking model and dynamic mesh model, is developed and validated in Zhundong lignite combustion in a pilot-scale furnace. With the employment of this model, a smooth growth of deposition and an accurate simulation can be achieved without applying the mesh smoothing strategy. Further, the predicted results are in good agreement with the experimental data. The effects of two mesh smoothing methods, which are the mass spreading algorithm and the group-averaged redistribution method, have been investigated under different furnace operation conditions. Compared to the simulations without the smoothing methods, a smaller particle count is required during the simulation to obtain the accurate, efficient and stable predicted results. The smoothing methods make a small difference (within 3.0%) on the predicted heat flux and deposition rate. In contrast, the deposition thickness at the tube position α=180° after two deposition hours would be within 16.8% smaller compared to the predicted results without the smoothing methods.

Concentrated solar power (CSP) has gained traction for generating electricity at high capacity and meeting base-load energy demands in the energy mix market in a cost-effective manner. The linear Fresnel reflector (LFR) is valued for its cost-effectiveness, reduced capital and operational expenses, and limited land impact compared to alternatives such as the parabolic trough collector (PTC). To this end, the aim of this study is to optimize the operational parameters, such as the solar multiple (SM), thermal energy storage (TES), and fossil fuel (FF) backup system, in LFR power plants using molten salt as a heat transfer fluid (HTF). A 50 MW LFR power plant in Duba, Saudi Arabia, serves as a case study, with a Direct Normal Irradiance (DNI) above 2500 kWh/m2. About 600 SM-TES configurations are analyzed with the aim of minimizing the levelized cost of electricity (LCOE). The analysis shows that a solar-only plant can achieve a low LCOE of 11.92 ¢/kWh with a capacity factor (CF) up to 36%, generating around 131 GWh/y. By utilizing a TES system, the SM of 3.5 and a 15 h duration TES provides the optimum integration by increasing the annual energy generation (AEG) to 337 GWh, lowering the LCOE to 9.24 ¢/kWh, and boosting the CF to 86%. The techno-economic optimization reveals the superiority of the LFR with substantial TES over solar-only systems, exhibiting a 300% increase in annual energy output and a 20% reduction in LCOE. Additionally, employing the FF backup system at 64% of the turbine’s rated capacity boosts AEG by 17%, accompanied by a 5% LCOE reduction. However, this enhancement comes with a trade-off, involving burning a substantial amount of natural gas (503,429 MMBtu), leading to greenhouse gas emissions totaling 14,185 tonnes CO₂ eq. This comprehensive analysis is a first-of-a-kind study and provides insights into the optimal designs of LFR power plants and addresses thermal, economic, and environmental considerations of utilizing molten salt with a large TES system as well as employing natural gas backup. The outcomes of the research address a wide audience including academics, operators, and policy makers.

The aim of the study was to investigate the impact of adding kaolin on the partitioning of chemical elements in the particulate matter (PM) when virgin and waste woody biomass fuels were fired in a 250 kW grate boiler. A comprehensive analysis of the chemical compositions of the PM has been conducted, including alkali and nonvolatile species, size-fractionated mass concentrations and micromorphology images. The results showed that the PM emission levels were significantly decreased by approximately 70-76 % and 60-66 % after the addition of kaolin to virgin wood (VW) and grade A recycled wood (RW), respectively, which inhibited the partitioning of the alkali species into fine and ultrafine PM. On the other hand, the concentration of the non-volatile elements, SiO2 and Al2O3, significantly increased in the PM emissions after the addition of kaolin due to the adhesion and aggregation of particulates between airborne kaolin and the fine and ultrafine PM. Moreover, the addition of the kaolin at 1.55 wt% showed comparable effects with that at 2.5 wt% on the chemical composition of PM emission. Furthermore, the SEM morphology suggested that KCl salts were diminished after the addition of the kaolin. These findings demonstrate the practicality of adding kaolin to mitigate PM emissions and their impacts in actual biomass combustion scenarios.

The viability of graphene-based microporous layers (MPLs) for polymer electrolyte membrane fuel cells is critically assessed through detailed characterisation of the morphology, microstructure, transport properties and electrochemical characterisation. Microporous layer composition was optimised by the fabrication of several hybrid MPLs produced from various ratios of graphene to Vulcan carbon black. Single cell tests were performed at various relative humidities between 25% and 100% at 80 degrees C, in order to provide a detailed understanding of the effect of the graphene-based MPL composition on the fuel cell performance. The inclusion of graphene in the MPL alters the pores size distribution of the layer and results in presence of higher amount of mesopores. Polarisation curves indicate that a small addition of graphene (i.e. 30 wt %) in the microporous layer improves the fuel cell performance under low humidity conditions (e.g. 25% relative humidity). On the other hand, under high humidity conditions (>= 50% relative humidity), adding higher amounts of graphene (>= 50 wt %) improves the fuel cell performance as it creates a good amount of mesopores required to drive excess water away from the cathode electrode, particularly when operating with high current densities. (c) 2023 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/4.0/).

Renewable energy desalination is gaining much attention in remote off-grid communities facing challenges in accessing clean water. Typically, batteries ensure the continuous operation of small-scale renewable reverse osmosis (RO) desalination systems; however, they are expensive and have relatively shorter lifespans. This study investigates the implementation of a compressed air energy storage (CAES) system coupled with a vertical axis wind turbine (VAWT) to directly drive small-scale RO desalination, potentially replacing batteries and reducing energy conversions. A Simulink model was developed to simulate the performance of a VAWT-driven CAES operating RO units, adaptable for both technical and economic assessments. Parametric studies have identified the optimal configuration. The most cost-effective configuration, utilising eleven VAWTs and a pressure exchanger (PX), achieves a levelised cost of water (LCOW) of 1.63 US$/m(3) and an annual water production of 9400 m(3). The normalised daily water production per square metre of turbine swept area at the study site is 0.19 m(3)/m(2)/day at an average wind speed of 5 m/s. While this configuration has a higher initial capital cost, it yields the lowest LCOW. The CAES system effectively addresses the intermittency challenges of wind energy. This study presents a novel, battery-free VAWT-CAES-RO system as a sustainable desalination solution for remote communities, offering a promising approach to address water scarcity in an environmentally friendly manner.

The paper deals with exhaustive process modelling, techno-economic and life cycle assessment (TEA/LCA) of olefin (ethylene and propylene) production through captured CO2 and electrolytic hydrogen. Olefins are important building block chemicals with several applications and carbon capture and utilisation (CCU) can provide a sustainable production route. The proposed system involves direct air capture (DAC) of CO2; proton exchange membrane (PEM) water electrolysis for hydrogen production, methanol synthesis, methanol to olefins (MTO) upgrade, and power generation from off-shore wind turbines. This study proposes a new integrated process as the first attempt to holistically assess a whole CCU assembly aiming at olefins production. Processing modelling has been implemented using the Aspen plus V12.1 and MATLAB R2022a software to solve the mass and energy balances of each unit operation. The modelling results showed a carbon efficiency of 72.3% to ethylene and propylene. In addition, the process is designed and integrated in such a way that no external heat supply is required. A specific energy consumption (SEC) of 150 MJ/kg olefins (41 kWh/kg) has been estimated. A minimum selling price of 3.67 pound per kg of olefins is required for the proposed process to break-even. The sensitivity analysis has revealed that the major cost driver is the cost of electricity. In addition, the life cycle assessment (LCA) has exposed that the proposed synthesis route of olefins has the potential to reduce the global warming potential (GWP) by 47% compared to fossil- based production. The outcomes of this study can be beneficial to engineering conceptual studies, policy makers and contribute new information to the CCU academic community.

A new predictive numerical model, Ia has been developed to predict the tendency of bed agglomeration in fluidized bed boilers. The model was developed based on the melt-induced mechanism of bed agglomeration, with a focus on the melt fraction resulting from the thermodynamic equilibrium calculation of fuel ash compositions together with SiO2 as the bed material. The results show that the new index, Ia demonstrated a significantly higher success rate in predicting the bed agglomeration tendency of biomass fuel ash compared to the experimental observations found in the literature. The K2O is the main element that accelerates the formation of bed agglomeration in the biomass firing while CaO was found to reduce the tendency of bed agglomeration in FBC system. In addition, it is observed that a reduction in the P2O5/CaO ratio leads to a decrease in the potential for bed agglomeration, shifting from high to low.

Nickel foams feature superior structural and transport characteristics and are therefore strong candidates to be used as gas diffusion layers (GDLs) in polymer electrolyte fuel cells (PEFCs). In this work, the impact of compression on the key structural and transport properties has been investigated, including employing a specially designed compression apparatus and X-ray computed tomography. Namely, 20 equally spaced two-dimensional CT based images and numerical models have been used/developed to investigate the sensitivity of the key properties of nickel foams (porosity, tortuosity, pore size, ligament thickness, specific surface area, gas permeability and effective diffusivity) to realistic compressions normally experienced in PEFCs. Wherever applicable, the anisotropy in the property has been investigated. One of the notable findings is that, unlike porosity and ligament thickness, the mean pore size was found to decrease significantly with compression. The mean pore size is around 175 mm for uncompressed nickel foam and it decreased to around 110 mm for a 20% compression ratio and to around 70 mm for a 40% compression ratio. Further, unlike the effective diffusivity, the gas permeability was shown to be highly anisotropic with compression; this fact is of particular importance for PEFC modelling where the properties of GDLs are often assumed isotropic. All the computationally estimated properties have been presented, validated and discussed. (c) 2023 The Authors. Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY license (http://creativecommons.org/