Browsing by Author "Wadi, Basil"
Now showing 1 - 9 of 9
Results Per Page
Sort Options
Item Open Access Advances, challenges, and perspectives of biogas cleaning, upgrading, and utilisation(Elsevier, 2022-02-05) Golmakani, Ayub; Nabavi, Seyed Ali; Wadi, Basil; Manovic, VasilijeBiogas as a renewable energy resource can be broadly recognised as a carbon–neutral fuel which reduces anthropogenic greenhouse gas emissions, mitigates global warming, and diversifies energy supply. However, the biogas share in the global renewable energy supply chain and technology deployment and maturity are not commensurate with the potential. The first half of this study critically reviews state of the art developments in biogas cleaning and upgrading technologies by considering their present status, current challenges, and barriers associated with their future development. The second part of this paper aims to address critical gaps in converting biogas to biomethane, proposing required pre-treatment steps for different technologies. The third part focuses on current policies concerning the strict regulations implemented for flaring consent applications. In this section, biogas upgrading technologies were compared by estimating the global warming potential (GWP) resulting from waste gases (WG). It was observed that due to high methane losses, WGs from membrane technologies have the highest GWP, but with flaring have the lowest GWP. In the last part of this review, the recent applications of biogas in cogeneration (CHP), tri-generation (CCHP), quad-generation systems, heat, and vehicles are discussed. The use of biogas by different technologies, and their resulting efficiencies were analysed in CHP applications, including microturbines, micro humid air turbine (mHAT), solid oxide fuel cells (SOFC) and hybrid systems of SOFC-microturbines.Item Open Access Amine functionalised SBA-15 for DAC - Data Set(Cranfield University, 2021-08-23 08:55) Wadi, Basil; Golmakani, Ayub; ali Nabavi, Seyed; Manovic, VasilijeRaw Data Set accompanying scientific article titled: Evaluation of Moderately Grafted Primary, Diamine, and Triamine Sorbents for CO2 Adsorption from Ambient Air: Balancing Kinetics and Capacity Under Humid ConditionsItem Open Access Comparative evaluation of PSA, PVSA, and twin PSA processes for biogas upgrading: the purity, recovery, and energy consumption dilemma(MDPI, 2023-09-27) Golmakani, Ayub; Wadi, Basil; Manovic, Vasilije; Nabavi, Seyed AliThe current challenges of commercial cyclic adsorption processes for biogas upgrading are associated with either high energy consumption or low recovery. To address these challenges, this work evaluates the performance of a range of configurations for biogas separations, including pressure swing adsorption (PSA), pressure vacuum swing adsorption (PVSA), and twin double-bed PSA, by dynamic modelling. Moreover, a sensitivity analysis was performed to explore the effect of various operating conditions, including adsorption time, purge-to-feed ratio, biogas feed temperature, and vacuum level, on recovery and energy consumption. It was found that the required energy for a twin double-bed PSA to produce biomethane with 87% purity is 903 kJ/kg CH4 with 90% recovery, compared to 961 kJ/kg CH4 and 76% recovery for a PVSA process. With respect to minimum purity requirements, increasing product purity from 95.35 to 99.96% resulted in a 32% increase in energy demand and a 23% drop in recovery, illustrating the degree of loss in process efficiency and the costly trade-off to produce ultra-high-purity biomethane. It was concluded that in processes with moderate vacuum requirements (>0.5 bar), a PVSA should be utilised when a high purity biomethane product is desirable. On the other hand, to minimise CH4 loss and enhance recovery, a twin double-bed PSA should be employed.Item Open Access Effect of combined primary and secondary amine loadings on the adsorption mechanism of CO2 and CH4 in biogas(Elsevier, 2021-05-12) Wadi, Basil; Golmakani, Ayub; Manovic, Vasilije; Nabavi, Seyed AliBiomethane, produced by biogas upgrading, is a promising energy source that can play a key role towards net-zero emissions targets. The incorporation of amine functionalities into adsorbents for biogas upgrading can facilitate the selective adsorption of CO2, but their effect has not been comprehensively studied within the context of CH4 mixtures. In this work, the effectiveness of amine functionalities in selectively separating CO2 from biogas, is investigated. Primary, diamine, and triamine organo-silanes grafted at various loadings on SBA-15 were used to study the adsorption mechanisms associated with amine functionalities for CO2:CH4 gas mixtures. The successful incorporation of amines was confirmed with thermogravimetric analysis (TGA), Fourier Transform Infrared (FTIR), and elemental analysis (EA). The different amine reagents and loadings resulted in an alteration of adsorption mechanism that provided key information on the developing relationship between adsorption capacity, selectivity, and energy efficiency. Diamine with an amine loading of 2.5 mmol/g and a moderate silane coverage of 1.54 molecules/nm2 was found to provide the best balance of an enhanced CO2 adsorption capacity (1.12 mmol/g), a superior selectivity to densely grafted primary amines, and the lowest isosteric heat of adsorption of ∼25 kJ/mol at 1.12 mmol/g compared to ∼41 kJ/mol for primary and triamine materials. Amongst all the samples, a lower amine loading on the bare adsorbent enhanced CO2 adsorption capacity and selectivity while minimising the heat duty associated with adsorbent regeneration. Moreover, under isothermal desorption conditions at 25 °C, some samples achieved working capacities comparable to higher amine loaded materialsItem Open Access Evaluation of moderately grafted primary, diamine, and triamine sorbents for CO2 adsorption from ambient air: balancing kinetics and capacity under humid conditions(American Chemical Society, 2021-08-30) Wadi, Basil; Golmakani, Ayub; Manovic, Vasilije; Nabavi, Seyed AliSuccessful deployment of direct air capture (DAC) to mitigate the consequences of climate change depends on many factors, one of which is the development of kinetically efficient CO2 sorbents with a high sorption capacity, at ultralow CO2 concentrations. This work evaluated CO2 adsorption performance of primary-, diamine-, and triamine-grafted SBA-15 at pressures below 5 kPa for DAC applications, measured through volumetric sorption, followed by humid air (23% RH) adsorption by gravimetric analysis. Under humid air flow, triamines at an amine loading of 4.6 mmol/g showed the highest enhancement in adsorption, with an uptake of 26 mg/g, but the slowest average adsorption rate of 216 μg/g/min. Diamine at an amine loading of 2.78 mmol/g had an adsorption rate of 295 μg/g/min but demonstrated the lowest uptake of 13 mg/g. In comparison, primary amines at a loading of 2.6 mmol/g reached an equilibrium uptake of 22 mg/g, with a higher adsorption rate of 354 μg/g/min. Triamine grafted at 3.5 mmol/g had the fastest kinetics of all samples, reaching 525 μg/g/min. Results indicated that primary amines and moderate-to-high density triamine reagents incorporated into mesoporous media can offer a superior adsorption rate that can make up for lower adsorption capacities, by optimizing cyclic performance, and should be considered when designing for continuous DAC processes.Item Open Access Formulation, adsorption performance, and mechanical integrity of triamine grafted binder-based mesoporous silica pellets for CO2 capture(Elsevier, 2021-07-16) Wadi, Basil; Mahomed, Anisa; Bai, Yang; Osatiashtiani, Amin; Manovic, Vasilije; Nabavi, Seyed AliThis work explored formulation of mesoporous silicas pellets using a range of bentonite and colloidal silica (LUDOX), aiming to optimise the binder composition that minimises any deteriorating effects on adsorption performance, while provides an adequate mechanical integrity. Thermogravimetric analysis, scanning electron microscopy, and dynamic mechanical analysis were used to structurally characterise the pellets. Furtherer, CO2 adsorption isotherms of synthesised pellets, pre and post triamine grafting, were measured. Bentonite was found to be an effective single binder that forms mechanically strong pellets and retains up to 85% of CO2 capacity of the base adsorbent. At the presence of LUDOX, hardness of the pellets was lower, caused the largest decrease in CO2 capacity. Formulation with 25% bentonite was found to provide pellets with post triamine functionalisation CO2 capacity equivalent to powder SBA-15, at an amine efficiency of 0.41 mol CO2/mol, while minimising pore blockage and maintaining a compressive strength of 1.5 MPa.Item Open Access Molecular simulation techniques as applied to silica and carbon-based adsorbents for carbon capture(MDPI, 2023-06-28) Wadi, Basil; Golmakani, Ayub; Borhani, Tohid N.; Manovic, Vasilije; Nabavi, Seyed AliThere has been ongoing interest in research to mitigate climate change through carbon capture (CC) by adsorption. This guideline is meant to introduce computational chemistry techniques in CC by applying them to mesoporous structures and disordered morphologies. The molecular simulation techniques presented here use examples of literature studies on silica and carbon-based adsorbents. An initial summary of molecular simulation techniques and concepts is first presented. This is followed by a section on molecular simulation applications in mesoporous amorphous silica, both functionalized and not. Novel strategies to validate and output useful results are discussed, specifically when modelling chemisorption. The use of computational chemistry to build upon experimental results is reviewed, and a similar summation is presented for carbon-based adsorbents. The final section provides a short review of computational chemistry methods in novel applications and highlights potential complications. Computational chemistry techniques provide a streamlined method of gathering data across a range of conditions. Alongside experimental studies, these techniques can provide valuable information on underlying molecular mechanisms. This paper aims to be a starting point for navigating these numerical methods by providing an initial understanding of how these techniques can be applied to carbon capture while clarifying the current and inherent limitations present.Item Open Access SBA-15 Pelletisation - Data Set(Cranfield University, 2021-08-12 10:42) Wadi, Basil; ali Nabavi, Seyed; Manovic, VasilijeData set accompanying article to be published in Powder technology titled: Formulation, Adsorption Performance, and Mechanical Integrity of Triamine Grafted Binder-Based Mesoporous Silica Pellets for CO2 Capture.Item Open Access 'Wadi et al. adsorption data set - Effect of combined primary and secondary amine loadings on the adsorption mechanism of CO2 and CH4 in biogas'(Cranfield University, 2021-05-25 09:17) Wadi, Basil; ali Nabavi, Seyed; Golmakani, Ayub; Manovic, VasilijeData set for amine functinalised SBA-15 with primary, diamine and triamine reagents. The attached data includes volumetric gas adsorption and TGA adsorption results for CO2 and CH4, and associated with the publication listed above.