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1.
  • Usman, Muhammad, et al. (author)
  • Use of Gasoline, LPG and LPG-HHO Blend in SI Engine : A Comparative Performance for Emission Control and Sustainable Environment
  • 2020
  • In: Processes. - : MDPI. - 2227-9717. ; 8:1
  • Journal article (peer-reviewed)abstract
    • The rising global warming concerns and explosive degradation of the environment requires the mainstream utilization of alternative fuels, such as hydroxy gas (HHO) which presents itself as a viable substitute for extracting the benefits of hydrogen. Therefore, an experimental study of the performance and emission characteristics of alternative fuels in contrast to conventional gasoline was undertaken. For experimentation, a spark ignition engine was run on a multitude of fuels comprising of gasoline, Liquefied petroleum gas (LPG) and hybrid blend of HHO with LPG. The engine was operated at 60% open throttle with engine speed ranging from 1600 rpm to 3400 rpm. Simultaneously, the corresponding performance parameters including brake specific fuel consumption, brake power and brake thermal efficiency were investigated. Emission levels of CO, CO2, HC and NOx were quantified in the specified speed range. To check the suitability of the acquired experimental data, it was subjected to a Weibull distribution fit. Enhanced performance efficiency and reduced emissions were observed with the combustion of the hybrid mixture of LPG with HHO in comparison to LPG: on average, brake power increased by 7% while the brake specific fuel consumption reduced by 15%. On the other hand, emissions relative to LPG decreased by 21%, 9% and 21.8% in cases of CO, CO2, and unburned hydrocarbons respectively. Incorporating alternative fuels would not only imply reduced dependency on conventional fuels but would also contribute to their sustainability for future generations. Simultaneously, the decrease in harmful environmental pollutants would help to mitigate and combat the threats of climate change.
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2.
  • Farooq, Muhammad, et al. (author)
  • Thermodynamic Performance Analysis of Hydrofluoroolefins (HFO) Refrigerants in Commercial Air-Conditioning Systems for Sustainable Environment
  • 2020
  • In: Processes. - : MDPI. - 2227-9717. ; 8:2
  • Journal article (peer-reviewed)abstract
    • Global warming is one of most severe environmental concerns that our planet is facing today. One of its causes is the previous generation of refrigerants that, upon release, remain in the atmosphere for longer periods and contribute towards global warming. This issue could potentially be solved by replacing the previous generation's high global warming potential (GWP) refrigerants with environmentally friendly refrigerants. This scenario requires an analysis of new refrigerants for a comparison of the thermodynamic properties of the previously used refrigerants. In the present research, a numerical study was conducted to analyze the thermodynamic performance of specifically low GWP hydrofluoroolefens (HFO) refrigerants for an actual vapor compression refrigeration cycle (VCRC) with a constant degree of 3 K superheat. The output parameters included the refrigeration effect, compressor work input, the coefficient of performance (COP), and the volumetric refrigeration capacity (VRC), all of which were calculated by varying the condenser pressure from 6 to 12 bars and vapor pressure from 0.7 to 1.9 bars. Results showed that R1234ze(Z) clearly possessed the desired thermodynamic performance. The drop in refrigeration effect for R1234ze(Z) was merely 14.6% less than that of R134a at a 12 bar condenser pressure; this was minimum drop among candidate refrigerants. The drop in the COP was the minimum for R1234ze(Z)-5.1% less than that of R134a at a 9 bar condenser pressure and 4.7% less than that of R134a at a 1.9 bar evaporator pressure, whereas the COP values of the other refrigerants dropped more drastically at higher condenser pressures. R1234ze(Z) possessed favorable thermodynamic characteristics, with a GWP of 7, and it can serve as an alternative refrigerant for refrigeration systems for a sustainable environment.
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3.
  • Naqvi, Salman Raza, et al. (author)
  • Agro-industrial residue gasification feasibility in captive power plants : A South-Asian case study
  • 2021
  • In: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 214
  • Journal article (peer-reviewed)abstract
    • The objective of this study is to build knowledge on the potential of agro-industrial residue gasification (AIRG) for use in captive power generation through a comprehensive case study. In order to evaluate the economic viability, key performance indicators, such as net present value (NPV), levelized cost of electricity (LCOE), and operating costs etc. are studied. The major textile industry located in the Raiwind area of Punjab province of Pakistan has been selected. The effect and variations of the capacity factor has also been studied coupled with the levelized cost of electricity. The agricultural residue as feedstock to the gasifier is rice husk that is the abundantly available in South Asia. Furthermore, the impact of government subsidies on natural gas is also under the scope of the study. The agro-industrial residue gasification system is found to be a potential alternative to furnace oil (FO) or gas-based captive power plants (CPPs). The results of residue-based gasification system imply a large potential when comparing the cost of electricity with national grid electricity during the peak hours. Therefore, the proposed gasification system offers economic incentives when the textile industry potentially utilizes gasification-based electricity during peak hours and national grid electricity during off-peak hours. (C) 2020 Elsevier Ltd. All rights reserved.
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4.
  • Arslan, Muhammad, et al. (author)
  • Impact of Varying Load Conditions and Cooling Energy Comparison of a Double-Inlet Pulse Tube Refrigerator
  • 2020
  • In: Processes. - : MDPI. - 2227-9717. ; 8:3
  • Journal article (peer-reviewed)abstract
    • Modeling and optimization of a double-inlet pulse tube refrigerator (DIPTR) is very difficult due to its geometry and nature. The objective of this paper was to optimize-DIPTR through experiments with the cold heat exchanger (CHX) along the comparison of cooling load with experimental data using different boundary conditions. To predict its performance, a detailed two-dimensional DIPTR model was developed. A double-drop pulse pipe cooler was used for solving continuity, dynamic and power calculations. External conditions for applicable boundaries include sinusoidal pressure from an end of the tube from a user-defined function and constant temperature or limitations of thermal flux within the outer walls of exchanger walls under colder conditions. The results of the system's cooling behavior were reported, along with the connection between the mass flow rates, heat distribution along pulse tube and cold-end pressure, the cooler load's wall temp profile and cooler loads with varied boundary conditions i.e. opening of 20% double-inlet and 40-60% orifice valves, respectively. Different loading conditions of 1 and 5W were applied on the CHX. At 150 K temperature of the cold-end heat exchanger, a maximum load of 3.7 W was achieved. The results also reveal a strong correlation between computational fluid dynamics modeling results and experimental results of the DIPTR.
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5.
  • Naqvi, Salman Raza, et al. (author)
  • Recent developments on sewage sludge pyrolysis and its kinetics : Resources recovery, thermogravimetric platforms, and innovative prospects
  • 2021
  • In: Computers and Chemical Engineering. - : Elsevier. - 0098-1354 .- 1873-4375. ; 150
  • Journal article (peer-reviewed)abstract
    • Sewage sludge is a by-product of the wastewater treatment process, which has the potential to be a source of transport fuels, heat, and power using the pyrolysis process. Considering the prevalence and disposal issues associated with sewage sludge, the objective of this study is to critically review the recent advancements in sewage sludge pyrolysis and its kinetics obtained using the thermogravimetric techniques, and other associated different kinetic models documented in the literature. The study will identify optimum operating conditions and design parameters to obtain high yields. The state-of-the-art perspectives and the challenges associated with full-scale implementation are highlighted for biofuels and resource recovery from the sewage sludge. Furthermore, machine-learning approaches in thermal kinetics of pyrolysis are presented and discussed in terms of their effectiveness in predicting thermal kinetics data. Finally, the challenges for a successful implementation and commercial viability of sewage sludge pyrolysis are discussed.
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6.
  • Ali, Imtiaz, et al. (author)
  • Kinetic and thermodynamic analyses of dried oily sludge pyrolysis
  • 2021
  • In: Journal of the Energy Institute. - : Elsevier. - 1743-9671 .- 1746-0220. ; 95, s. 30-40
  • Journal article (peer-reviewed)abstract
    • Oily sludge has the potential to utilize in pyrolysis process effectively because of higher product recovery and lower harmful emissions. Due to the complex nature of reactions, it is necessary to evaluate the thermo-kinetic behavior of the process to make it commercially feasible. This study includes thermal degradation behavior, the kinetic and thermodynamic analysis of dry oily sludge by applying Friedman and Vyazovkin method (model-free approach), and Coats-Redfern method (model-fitting approach) with the help of thermogravimetric analysis TGA at different heating rates (5, 20, 40 °C/min). The active region was from 20 to 60% conversion range because the maximum conversion occurs in this region. The overall activation energy decreases as the conversion increases from a lower range (60%) to a higher range (80%) for all satisfied models. The estimated range of pre-exponential coefficient for each model was to 4.91E+15 to 2.30E-01min−1 in the conversion range of 20–60% and 9.80E+02 to 4.89E-04min−1 in the conversion range 60–80%. The overall value of the change in enthalpy ΔH and change in Gibbs free energy ΔG decrease as the conversion increases from the lower range to the higher range.
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7.
  • Anees, Hafiz Muhammad, et al. (author)
  • A mathematical model-based approach for DC multi-microgrid performance evaluations considering intermittent distributed energy resources, energy storage, multiple load classes, and system components variations
  • 2021
  • In: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; 9, s. 1919-1934
  • Journal article (peer-reviewed)abstract
    • The efficiency of DC microgrid needs investigation from a smart grid perspective, since their spread has expected to prevail in comparison with AC counterparts. Furthermore, there is a need to address the limitations (majorly to cater the intermittency of distributed energy resources (DERs) as well as the time dependency of systematic parameters etc.) in previous model and propose a new mathematical model to evaluate system efficiency for given parameters and scenarios. The core focus of current study aims at formulation of an improved (composite) mathematical model, that is capable of bridging issues and serve as a tool to address requirements of future DC systems including microgrids (MGs) and multi-microgrids (MMGs). This research work offers such a mathematical model that consists of 3D matrices based on newly derived set of discrete time dependent equations, which evaluates the system efficiency of residential DC-MMGs. Each DC-MG is embedded with intermittent DERs, storage, components (with efficiency variations), and multi-class load (with discrete time dependency), for evaluation across worst, normal, and best scenarios. A comprehensive sensitivity analysis across various cases and respective scenarios are also presented to evaluate overall system performance. Also, the impacts of system parameters on various system variables, states, and overall system efficiency have presented in this paper.
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8.
  • Farooq, Usman, et al. (author)
  • Synthesis of nZVI@reduced graphene oxide : an efficient catalyst for degradation of 1,1,1-trichloroethane (TCA) in percarbonate system
  • 2017
  • In: Research on chemical intermediates (Print). - : SPRINGER. - 0922-6168 .- 1568-5675. ; 43:5, s. 3219-3236
  • Journal article (peer-reviewed)abstract
    • Graphene-oxide-supported nano zero-valent iron (nZVI) composite (nZVI-rGO) was synthesized and tested as an efficient percarbonate activator for degradation of 1,1,1-trichloroethane (TCA). Significant dispersion of nZVI on the surface of reduced graphene oxide (rGO) was observed, with good limitation of nanoparticle agglomeration and aggregation. Good TCA degradation efficiency of 90% was achieved in 2.5 h in presence of 0.8 g/l nZVI-rGO catalyst and 30 mM sodium percarbonate (SPC) oxidant; however, excessive catalyst or oxidant concentration reduced the degradation efficiency. Investigation of reactive oxygen species using radical probe compounds as well as radical scavengers confirmed presence of hydroxyl (OH center dot) and superoxide () radicals that are responsible for the TCA degradation. The morphology and surface characteristics of the heterogeneous catalyst were analyzed by transmission electron microscopy and scanning electron microscopy. Brunauer-Emmett-Teller analysis revealed that the synthesized catalyst had large surface area and small particle size of 299.12 m(2)/g and 20.10 nm, respectively, compared with 5.33 m(2)/g and 1.12 A mu m for bare graphene oxide. X-ray diffraction analysis revealed good dispersion of nZVI on the surface of rGO. Fourier-transform infrared characteristic peaks confirmed strong attachment of Fe onto the rGO surface. Energy-dispersive spectroscopy analysis validated the stoichiometric composition of the prepared Fe/rGO material. In conclusion, use of nZVI-rGO-activated SPC could represent an alternative technique for remediation of TCA-contaminated groundwater.
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9.
  • Hussain, Arif, et al. (author)
  • Methoxy-methylheptane as a cleaner fuel additive : An energy- and cost-efficient enhancement for separation and purification units
  • 2021
  • In: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; :9, s. 1632-1646
  • Journal article (peer-reviewed)abstract
    • Environmental protection agencies have begun imposing stringent regulations on the existing refineries to control the levels of gasoline additives. In this context, a novel compound, 2-methoxy-2-methylheptane (MMH), had drawn attention as fuel additive for cleaner combustion. The conventional process of MMH production features three distillation columns in a direct sequence. These columns are used to maintain the required product purities and to utilize the unreacted reactants through recycling streams. The distillation system of the existing MMH plant can afford significant energy savings, leading to a reduction in the total annual costs (TAC). The aim of this investigation is to demonstrate that the reported conventional process can be significantly enhanced by modifying the design and operational parameters and by replacing two distillation columns with an intensified dividing wall column (DWC) configuration. The DWC design is further optimized using several algorithms such as the modified coordinate method (MCD), robust particle swarm paradigm (PSP), and firefly (FF) with nonlinear constraints. Compared to conventional process, the optimized DWC resulted in 24% and 11.5% savings in the plant operating and total annual costs, respectively.
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10.
  • Kazmi, Bilal, et al. (author)
  • Thermodynamic and economic assessment of cyano functionalized anion based ionic liquid for CO2 removal from natural gas integrated with, single mixed refrigerant liquefaction process for clean energy
  • 2022
  • In: Energy. - : Pergamon Press. - 0360-5442 .- 1873-6785. ; 239
  • Journal article (peer-reviewed)abstract
    • The study proposes a novel integrated process in which ionic liquid is utilized to control carbon dioxide (CO2) emissions from the natural gas combined with a single mixed refrigerant-based liquefaction process to assist safe transportation over long distances providing a sustainable and cleaner energy. Commercially amines are utilized for CO2 sequestration, but amines entail energy-intensive regeneration with elevated process costs. The present study offers a solvent screening mechanism based on important parameters such as heat of dissolution, viscosity, selectivity, working capacity, vapor pressure, corrosivity, and toxicity. The selected solvents' performance is computed by sensitivity analysis suggesting imidazolium-based cation 1-hexyl-3-methylimidazolium[Hmim] functionalized with tricyanomethanide(tcm) as anion a potential natural gas sweetening solvent in comparison with commercially used solvent monoethanoloamine(MEA), conventional ILs 1-butyl-3-methylimidazolium hexa-fluorophosphate [Bmim][Pf(6)] and 1-butyl-3-methylimidazolium methyl sulfate [Bmim][MeSO4]. The obtained sweet gas is liquefied using a single mixed refrigerant-based process providing 0.99 mol fraction of liquefied CH4 with less overall specific compression power requirement of 0.41 kW/kg of natural gas. Moreover, an exergy analysis demonstrates that the [Hmim][tcm] based process has lower total exergy destruction of 7.49 x 10(3) kW and is found to utilize less overall specific energy consumption 0.49 kWh/kg of NG in contrast to other studied solvents. Furthermore, a detailed economic analysis establishes [Hmim][tcm]-based CO2 integrated with liquefaction technology offers 50.7%, 74.4%, and 85.8% of total annualized cost (TAC) savings compared with the MEA-amim][Pf(6)]-, and [Bmim][MeSO4], respectively. Hence, [Hmim][tcm] for CO2 removal and integration with liquefaction process will incur unit cost based on the total annualized cost to be $2.2 x 10(4)/kmol of purified NG.
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11.
  • Manzoor, Numair, et al. (author)
  • RETRACTED: Experimental Study of CO2 Conversion into Methanol by Synthesized Photocatalyst (ZnFe2O4/TiO2) Using Visible Light as an Energy Source
  • 2020
  • In: Catalysts. - : MDPI. - 2073-4344. ; 10:2
  • Journal article (peer-reviewed)abstract
    • Ozone layer depletion is a serious threat due to the extensive release of greenhouse gases. The emission of carbon dioxide (CO2) from fossil fuel combustion is a major reason for global warming. Energy demands and climate change are coupled with each other. CO2is a major gas contributing to global warming; hence, the conversion of CO2 into useful products such as methanol, formic acid, formaldehyde, etc., under visible light is an attractive topic. Challenges associated with the current research include synthesizing a photocatalyst that is driven by visible light with a narrow band gap range between 2.5 and 3.0 eV, the separation of a mixed end product, and the two to three times faster recombination rate of an electron–hole pair compared with separation over yield. The purpose of the current research is to convert CO2 into useful fuel i.e., methanol; the current study focuses on the photocatalytic reduction of CO2into a useful product. This research is based on the profound analysis of published work, which allows the selection of appropriate methods and material for this research. In this study, zinc ferrite (ZnFe2O4) is synthesized via the modified sol–gel method and coupled with titanium dioxide (TiO2). Thereafter, the catalyst is characterized by Fourier transform infrared (FTIR), FE-SEM, UV–Vis, and XRD characterization techniques. UV–Vis illustrates that the synthesized catalyst has a low band gap and utilizes a major portion of visible light irradiation. The XRD pattern was confirmed by the formation of the desired catalyst. FE-SEM illustrated that the size of the catalyst ranges from 50 to 500 nm and BET analysis determined the surface area, which was 2.213 and 6.453 m2/g for ZnFe2O4 and ZnFe2O4/TiO2, respectively. The continuous gas flow photoreactor was used to study the activity of the synthesized catalyst, while titanium dioxide (TiO2) has been coupled with zinc ferrite (ZnFe2O4) under visible light in order to obtain the maximum yield of methanol as a single product and simultaneously avoid the conversion of CO2 into multiple products. The performance of ZnFe2O4/TiO2was mainly assessed through methanol yield with a variable amount of TiO2 over ZnFe2O4 (1:1, 1:2, 2:1, 1:3, and 3:1). The synthesized catalyst recycling ability has been tested up to five cycles. Finally, we concluded that the optimum conditions for maximum yield were found to be a calcination temperature of ZnFe2O4at 900 °C, and optimum yield was at a 1:1 w/w coupling ratio of ZnFe2O4/TiO2. It was observed that due to the enhancement in the electron–hole pair lifetime, the methanol yield at 141.22 μmol/gcat·h over ZnFe2O4/TiO2was found to be 7% higher than the earlier reported data.
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12.
  • Abbas, Shahrukh, et al. (author)
  • Impact Analysis of Large-Scale Wind Farms Integration in Weak Transmission Grid from Technical Perspectives
  • 2020
  • In: Energies. - : MDPI. - 1996-1073. ; 13:20
  • Journal article (peer-reviewed)abstract
    • The integration of commercial onshore large-scale wind farms into a national grid comes with several technical issues that predominately ensure power quality in accordance with respective grid codes. The resulting impacts are complemented with the absorption of larger amounts of reactive power by wind generators. In addition, seasonal variations and inter-farm wake effects further deteriorate the overall system performance and restrict the optimal use of available wind resources. This paper presented an assessment framework to address the power quality issues that have arisen after integrating large-scale wind farms into weak transmission grids, especially considering inter-farm wake effect, seasonal variations, reactive power depletion, and compensation with a variety of voltage-ampere reactive (Var) devices. Herein, we also proposed a recovery of significant active power deficits caused by the wake effect via increasing hub height of wind turbines. For large-scale wind energy penetration, a real case study was considered for three wind farms with a cumulative capacity of 154.4 MW integrated at a Nooriabad Grid in Pakistan to analyze their overall impacts. An actual test system was modeled in MATLAB Simulink for a composite analysis. Simulations were performed for various scenarios to consider wind intermittency, seasonal variations across four seasons, and wake effect. The capacitor banks and various flexible alternating current transmission systems (FACTS) devices were employed for a comparative analysis with and without considering the inter-farm wake effect. The power system parameters along with active and reactive power deficits were considered for comprehensive analysis. Unified power flow controller (UPFC) was found to be the best compensation device through comparative analysis, as it maintained voltage at nearly 1.002 pu, suppressed frequency transient in a range of 49.88-50.17 Hz, and avoided any resonance while maintaining power factors in an allowable range. Moreover, it also enhanced the power handling capability of the power system. The 20 m increase in hub height assisted the recovery of the active power deficit to 48%, which thus minimized the influence of the wake effect.
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13.
  • Azeem, Babar, et al. (author)
  • Production and Characterization of Controlled Release Urea Using Biopolymer and Geopolymer as Coating Materials
  • 2020
  • In: Polymers. - : MDPI. - 2073-4360. ; 12:2
  • Journal article (peer-reviewed)abstract
    • Synthetic polymers-based controlled release urea (CRU) leaves non-biodegradable coating shells when applied in soil. Several alternative green materials are used to produce CRU, but most of these studies have issues pertaining to nitrogen release longevity, process viability, and the ease of application of the finished product. In this study, we utilized tapioca starch, modified by polyvinyl alcohol and citric acid, as coating material to produce controlled release coated urea granules in a rotary fluidized bed equipment. Response surface methodology is employed for studying the interactive effect of process parameters on urea release characteristics. Statistical analysis indicates that the fluidizing air temperature and spray rate are the most influential among all five process parameters studied. The optimum values of fluidizing air temperature (80 degrees C), spray rate (0.13 mL/s), atomizing pressure (3.98 bar), process time (110 min), and spray temperature (70 degrees C) were evaluated by multi-objective optimization while using genetic algorithms in MATLAB((R)). Urea coated by modified-starch was double coated by a geopolymer to enhance the controlled release characteristics that produced promising results with respect to the longevity of nitrogen release from the final product. This study provides leads for the design of a fluidized bed for the scaled-up production of CRU.
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14.
  • Hameed, Zeeshan, et al. (author)
  • A Comprehensive Review on Thermal Coconversion of Biomass, Sludge, Coal, and Their Blends Using Thermogravimetric Analysis
  • 2020
  • In: Journal of Chemistry. - : Hindawi Publishing Corporation. - 2090-9063 .- 2090-9071. ; 2020
  • Research review (peer-reviewed)abstract
    • Lignocellulosic biomass is a vital resource for providing clean future energy with a sustainable environment. Besides lignocellulosic residues, nonlignocellulosic residues such as sewage sludge from industrial and municipal wastes are gained much attention due to its large quantities and ability to produce cheap and clean energy to potentially replace fossil fuels. These cheap and abundantly resources can reduce global warming owing to their less polluting nature. The low-quality biomass and high ash content of sewage sludge-based thermal conversion processes face several disadvantages towards its commercialization. Therefore, it is necessary to utilize these residues in combination with coal for improvement in energy conversion processes. As per author information, no concrete study is available to discuss the synergy and decomposition mechanism of residues blending. The objective of this study is to present the state-of-the-art review based on the thermal coconversion of biomass/sewage sludge, coal/biomass, and coal/sewage sludge blends through thermogravimetric analysis (TGA) to explore the synergistic effects of the composition, thermal conversion, and blending for bioenergy production. This paper will also contribute to detailing the operating conditions (heating rate, temperature, and residence time) of copyrolysis and cocombustion processes, properties, and chemical composition that may affect these processes and will provide a basis to improve the yield of biofuels from biomass/sewage sludge, coal/sewage sludge, and coal/biomass blends in thermal coconversion through thermogravimetric technique. Furthermore, the influencing factors and the possible decomposition mechanism are elaborated and discussed in detail. This study will provide recent development and future prospects for cothermal conversion of biomass, sewage, coal, and their blends.
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15.
  • Jamil, Asif, et al. (author)
  • Polyetherimide-Montmorillonite Nano-Hybrid Composite Membranes : CO2 Permeance Study via Theoretical Models
  • 2020
  • In: Processes. - : MDPI. - 2227-9717. ; 8:1
  • Journal article (peer-reviewed)abstract
    • The incorporation of aminolauric acid modified montmorillonite (f-MMT) in polyetherimide (PEI) has been implemented to develop hollow fibre nano-hybrid composite membranes (NHCMs) with improved gas separation characteristics. The aforementioned characteristics are caused by enhanced f-MMT spatial dispersion and interfacial interactions with PEI matrix. In this study, existing gas permeation models such as, Nielsen, Cussler, Yang-Cussler, Lape-Cussler and Bharadwaj were adopted to estimate the dispersion state of f-MMT and to predict the CO2 permeance in developed NHCMs. It was found out that the average aspect ratio estimated was 53, with 3 numbers of stacks per unit tactoid, which showed that the intercalation f-MMT morphology is the dominating dispersion state of filler in PEI matrix. Moreover, it was observed that Bharadwaj model showed the least average absolute relative error (%AARE) values till 3 wt. % f-MMT loading in the range of +/- 10 for a pressure range of 2 to 10 bar. Hence, Bharadwaj was the best fit model for the experimental data compared to other models, as it considers the platelets orientation.
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16.
  • Kazmi, Bilal, et al. (author)
  • Process system analysis on oil processing facility and economic viability from oil well-to-tank
  • 2021
  • In: SN Applied Sciences. - : Springer Science and Business Media LLC. - 2523-3963 .- 2523-3971. ; 3:7
  • Journal article (peer-reviewed)abstract
    • Hydrocarbon processing from extraction to the final product is an important aspect that needs an optimised technology for consumption-led market growth. This study investigated real data from the oil processing facility and analysed the simulation model for the entire crude oil processing unit based on the process system engineering aspect using Aspen HYSYS. The study mainly emphasises the process optimisation in processing the hydrocarbon for the maximum yield of the product with less energy consumption. The investigation also includes a thorough economic analysis of the processing facility. The datasets for oil properties are obtained from a modern petroleum refinery. The investigation comprises of varying transient conditions, such as well shutdowns using three oil reservoirs (low, intermediate, and heavy oil). The impact of various conditions, including process heating, well shutdown, oil combinations, presence of water on the production, is analysed. The results indicate that the factors involving crude oil processing are significantly affected by the process conditions, such as pressure, volume, and temperature. The vapour recovery unit is integrated with the oil processing model to recover the separator's gas. The optimisation analysis is performed to maximise the liquid recovery with Reid vapour pressure of 7 and minimum water content in oil around 0.5%. Economic analysis provided an overall capital cost of $ 9.7 x 10(6) and an operating cost of $2.1 x 10(6) for the process configuration. The model results further investigate the constraints that maximise the overall energy consumption of the process and reduce the operational cost.
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17.
  • Majeed, Khaliq, et al. (author)
  • Shuffled Complex Evolution-Based Performance Enhancement and Analysis of Cascade Liquefaction Process for Large-Scale LNG Production
  • 2020
  • In: Energies. - : MDPI. - 1996-1073. ; 13:10
  • Journal article (peer-reviewed)abstract
    • Among all large-scale natural gas (NG) liquefaction processes, the mixed fluid cascade (MFC) process is recognized as a best-alternative option for the LNG production, mainly due its competitive performance. However, from a thermodynamic point of view, the MFC process is still far from its potential maximum energy efficiency due to non-optimal execution of design variables. Therefore, the energy efficiency enhancement of the MFC process remains an ongoing issue. The design optimization after fixing the main configuration of the process is one of the most economic, but challenging exercises during the design stages. In this study, shuffled complex evolution (SCE) is studied to find the optimal design of the MFC process corresponding to minimal energy consumption in refrigeration cycles. The MFC process is simulated using Aspen Hysys((R)) v10 and then coupled with the SCE approach, which is coded in MATLAB((R)) 2019a. The refrigerant composition and operating pressures for each cycle of the MFC process were optimized considering the approach temperature inside the LNG heat exchanger as a constraint. The resulting optimal MFC process saved 19.76% overall compression power and reduced the exergy destruction up to 28.76%. The thermodynamic efficiency (figure of merit) of the SCE-optimized process was 25% higher than that of the published base case. Furthermore, the optimization results also imply that there is a trade-off between the thermodynamic performance improvement and the computational cost (no. of iterations). In conclusion, SCE exhibited potential to improve the performance of highly nonlinear and complex processes such as LNG processes.
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18.
  • Naqvi, Muhammad Raza, 1983-, et al. (author)
  • Off-grid electricity generation using mixed biomass compost: : A scenario-based study with sensitivity analysis
  • 2017
  • In: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 201, s. 363-370
  • Journal article (peer-reviewed)abstract
    • The aim of the study is to investigate the viability of waste gasification based off-grid electricity gener- ation utilizing mixed biomass composts (mixture of rice hulls with cow/poultry manure compost). The economic viability is studied on the different scenarios with considerations of (1) levels of electricity demand and utilization, (2) costs of variable biomass mix, (3) combined domestic and cottage industry business model, and (4) influence of governmental investments. The levelized cost of electricity (LCOE) is used as an indicator to measure the competitiveness of gasification based off-grid electricity genera- tion. The plant loading and the capacity factor have been used to assess the impacts of different scenarios. A sensitivity analysis of key parameters based on variations in annual operational hours, plant efficiency, plant cost and biomass supply cost is conducted. Based on levels of electricity demand and utilization, the LCOE ranged between 40 US cents/kW h and 29 US cents/kW h based on the plant loading and the capac- ity factor. The business revenue would not change considerably despite better plant utilization and reduced levelized cost of electricity if all the consumers, both basic or medium, are charged with the flat tariff. The part load operation will be costly despite considerably low capital investment per kW in com- parison with PV or solar based plants. There is a large potential of off-grid electricity generation but the estimated off-grid electricity price is found to be higher in all scenarios than average grid-based electric- ity tariff. Moreover, the challenges for the implementation of the real off-grid electricity generation plant are discussed. 
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21.
  • Naqvi, S. R., et al. (author)
  • Catalytic Consequences of Micropore Topology on Biomass Pyrolysis Vapors over Shape Selective Zeolites
  • 2017
  • In: Energy Procedia. - : Elsevier Ltd. - 1876-6102. ; , s. 557-561, s. 557-561
  • Conference paper (peer-reviewed)abstract
    • Research on utilization of abundant rice residue for valuable bioenergy products is still not explored completely. A simple, robust, cheap and one step fast pyrolysis reactor is still a key demand for production of bioenergy products, i.e. high quality bio-oil and bio char. Bio-oil produced from fast pyrolysis has poor quality (e.g. acidic and highly oxygenated). Catalytic fast pyrolysis using zeolites in the fast pyrolysis process effectively reduce the oxygen content (no H2 required). In this paper, zeolites having a variety of pore size and shape (small pore: SAPO-34 (0.56), Ferriertite (20), medium pore: ZSM-5 (23), MCM-22 (20), ITQ-2 (20) and large pore zeolite Mordenite (20) were tested in a drop type fixed-bed pyrolyzer. The catalytic deoxygenation is conducted at 450°C at the catalyst/biomass ratio of 0.1. Zeolite catalysts, its pore size and shape could influence largely on deoxygenation. Small pore zeolites did not produce aromatics while medium pore zeolites formed higher amount of aromatics. ZSM-5 and ITQ-2 zeolites were especially efficient for the higher deoxygenation of biomass pyrolysis vapors due to better pore dimension and higher acidity. © 2017 The Authors.
  •  
22.
  • Naqvi, Salman Raza, et al. (author)
  • Catalytic Pyrolysis Of Botryococcus Braunii (microalgae) Over Layered and Delaminated Zeolites For Aromatic Hydrocarbon Production
  • 2017
  • In: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - : ELSEVIER SCIENCE BV. ; , s. 381-385
  • Conference paper (peer-reviewed)abstract
    • Botryococcus braunii (B. Braunii) is considered as due to its high capability of large aromatic contents, prominent green microalgae as a renewable energy resource. The aim and novelty of this work is to exploit the pyrolysis characteristics of microalgae with layered and delaminated zeolites using Py-GC/MS. No catalyst and catalytic pyrolysis was compared to evaluate product components formed. Further, the catalytic pyrolysis of botryococcus braunii was carried out in the presence of two zeolites with different pore topology and acidity. The results from non-catalytic microalgae pyrolysis were compared to catalytic pyrolysis together with different catalysts to biomass ratios for aromatic hydrocarbons production. Py-GC/MS results showed the aromatic hydrocarbon production (area%) was significantly improved from zeolite catalytic pyrolysis than non-catalytic pyrolysis. The increase in catalyst to biomass ratio (3:1 and 5:1) resulted in higher aromatic hydrocarbon production. As the catalyst to biomass ratio increased, it is observed that aromatic hydrocarbon content increased as compared to low catalyst to biomass ratio. In addition, ITQ-2 zeolite generated higher aromatic hydrocarbons. This might be due to better pore structure and acidity of delaminated structure as compared to layered structure. This delaminated topology enhances the reactant diffusion and reduces the secondary cracking.
  •  
23.
  • Naqvi, Salman Raza, et al. (author)
  • Circular Economy Approach to Address the Industrial Solid Waste Management
  • 2022
  • In: Handbook of Solid Waste Management. - Singapore : Springer. - 9789811642296 - 9789811642302 ; , s. 421-440
  • Book chapter (other academic/artistic)abstract
    • Industrial activities continuously generate diverse characteristics of various types of wastes. Industrial wastes varied from various process residues, wastes from pollution, or decontamination from operations and materials resulting from activities for contaminated soil remediation, ashes, oil, acidic wastes, plastic, paper, wood, fiber, rubber, metals, and glass. The circular tools indicate a restorative and regenerative system in which the streams of materials and products take place in a circular way. Considering social pressures, major industrial enterprises perceived the need for readjusting their production chains according to circular chains, which are more sustainable and consider the generated waste. This study aims to present the factors for sustainable waste management in major industrial enterprises based on the circular economy approach. The available data of a waste company is considered, and the model of circular economy such as fault tree analysis is applied to figure out the implementation of a circular process to industrial waste, especially those of lower value that have greater difficulties in being processed. The last section will propose a framework, opportunities, challenges, and trade-offs promoting circulatory industrial waste management.
  •  
24.
  • Naqvi, Salman Raza, et al. (author)
  • Impact of layered and delaminated zeolites on catalytic fast pyrolysis of microalgae using fixed-bed reactor and Py-GC/MS
  • 2021
  • In: Journal of Analytical and Applied Pyrolysis. - : Elsevier. - 0165-2370 .- 1873-250X. ; 155
  • Journal article (peer-reviewed)abstract
    • The aim of this work is to exploit the pyrolysis characteristics of microalgae Botryococcus braunii (BB) with a medium pore framework zeolite (MCM-22) and its delaminated counterpart with a higher external surface area zeolite (ITQ-2) using pyrolysis-gas-chromatography-mass-spectrometry (Py-GC/MS) and a fixed-bed reactor. The study evaluates the effect of synthesized zeolites that possess different pore size, shape and acidity on promoting deoxygenation reactions and producing aromatic compounds during the pyrolysis of microalgae. Further, the role of the shape of zeolites (layered & delaminated) for carbohydrate, protein and lipid-derived compounds formation is discussed. The Py-GC/MS results showed that the aromatic compounds (area%) was significantly higher (35.17 %) for delaminated & (28.76 %) for layered zeolites than non-catalytic pyrolysis (17.85 %) at the catalyst/biomass ratio of 10.1. The increase in catalyst/biomass ratio from 3 to 10 at 550 °C has increased the aromatics (90.66 % for ITQ-2 & 75.25 %) for MCM-22 zeolites. In addition, ITQ-2 zeolite produced 20.47 % higher aromatics than MCM-22 zeolites which is attributed to the thinner delaminated structure of ITQ-2 that makes reactants more accessible to the catalytic site and accelerate the deoxygenation reactions.
  •  
25.
  • Qyyum, Muhammad Abdul, et al. (author)
  • Weed colonization-based performance improvement opportunities in dual-mixed refrigerant natural gas liquefaction process
  • 2021
  • In: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; 9:2, s. 297-312
  • Journal article (peer-reviewed)abstract
    • Dual-mixed refrigerant (DMR) process is a promising candidate for liquefying the natural gas (LNG) at onshore as well as offshore sites, thanks to its higher liquefaction capacity and flexibility in using full gas turbines. DMR involves two mixed refrigerant cycles to perform precooling and subcooling of natural gas (NG), and these refrigerant compositions need constant tweaking to match the ever-changing NG cooling curve, as it is obtained from different gas fields. Mismatching of cooling curves often results in suboptimal operation, which ultimately leads to an increase in the overall energy consumption. Thus, this study is aimed at making DMR liquefaction operation close to optimal using the invasive-weed paradigm. At first, the decision variables for performance improvement were determined using degrees of freedom analysis then through invasive-weed paradigm the best set of parameters that results in minimal overall energy consumption were obtained. For the given set of conditions, it was found that after optimization, the DMR process can produce LNG using 16.2% less compression power compared to the published optimized DMR process. Taking into account the higher sensitivity of the DMR process against NG feed conditions, the IWO approach was also examined to find the multiple optimal solutions corresponding to different sets of feed conditions. The thermodynamic evaluation revealed that the mixed refrigerant involves in NG subcooling and interstage coolers have the highest level of exergy destruction. After successful performance improvement of the DMR process, it is also found that still, 62% improvement potential (based on avoidable/unavoidable exergy destruction analysis) is available in the DMR process that can be attained through either sole optimization or optimal retrofitting/revamping.
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26.
  • Taqvi, Syed Ali Ammar, et al. (author)
  • Simultaneous fault diagnosis based on multiple kernel support vector machine in nonlinear dynamic distillation column
  • 2022
  • In: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; 10:3, s. 814-839
  • Journal article (peer-reviewed)abstract
    • Although numerous works have been done, most of the studies in fault diagnosis are limited to single fault type at a time. Majority of the works reported in the literature do not extend the diagnosis of the root cause of the fault for simultaneous faults specifically in the distillation column. However, an industrial system is susceptible to more than one fault at a time, which may or may not be interrelated. These faults not only reduce the diagnosis performance but also increase the computational complexity of the diagnosis algorithm. In this work, therefore, a multiple kernel support vector machine (MK-SVM) algorithm is proposed to diagnose simultaneous faults in the distillation column. In the developed MK-SVM algorithm, multilabel approach based on various kernel functions has been utilized for the classification of simultaneous faults. Dynamic simulation of a pilot-scale distillation column using Aspen Plus(R) is used for generating data in normal and faulty operation. Eight different fault types are considered, including valve sticking at reflux and reboiler, tray upsets, loss of feed flow, feed composition, and feed temperature changes. In the classification of simultaneous faults, a combination of two, three, and four faults is introduced for the performance evaluation of the proposed MK-SVM algorithm. The result showed that the proposed MK-SVM has a high fault detection rate (FDR) of 99.51% and a very low misclassification rate (MR) of 0.49%. The MK-SVM-based classification is better with the F1 score of >97% for all combinations of faults. Moreover, it is observed that the proposed MK-SVM shows better fault diagnosis for single, multiple, and simultaneous faults as compared to other established machine-learning algorithms.
  •  
27.
  • Ul Haq, Sheikh Ehsan, et al. (author)
  • Multistage carbon dioxide compressor efficiency enhancement using waste heat powered absorption chillers
  • 2021
  • In: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; 9:9, s. 1373-1384
  • Journal article (peer-reviewed)abstract
    • The performance of a multistage centrifugal compressor is highly influenced by the ambient conditions, especially during the summer seasons; their capacity shrinks and thus the power requirement for compression will increase. The prime cause of these constraints is the interstage cooling limitations. This study simulates various suction conditions of a multistage compressor on Aspen HYSYS (R) and suggests its debottlenecking by making the suction temperatures comparable to winter seasons. This is achieved by installing an additional exchanger at the downstream of each interstage cooler, cooling down the gas further by using absorption refrigeration chillers. These chillers are powered up by the waste heat recovered from the exhaust steam coming from the prime mover, steam turbine, of the same compressor. This modification will save a considerable amount of power (663 kW), net savings (Gross Savings - OPEX: 72 289 $/y), and reduce the carbon footprint (954 ton/y) of the overall process.
  •  
28.
  • Anukam, Anthony, et al. (author)
  • A Review of the Chemistry of Anaerobic Digestion : Methods of Accelerating and Optimizing Process Efficiency
  • 2019
  • In: Processes. - Basel : MDPI. - 2227-9717. ; 7:8, s. 1-19
  • Research review (peer-reviewed)abstract
    • The anaerobic digestion technology has been in existence for centuries and its underlying theory established for decades. It is considered a useful technology for the generation of renewable energy, and provides means to alleviate problems associated with low access to energy. However, a great deal of current research is targeted towards the optimization of this technology under diverse digestion process conditions. This review presents an in-depth analysis of the chemistry of anaerobic digestion and discusses how process chemistry can be used to optimize system performance through identification of methods that can accelerate syntrophic interactions of different microorganisms for improved methanogenic reactions. Recent advances in addition to old research are discussed in order to offer a general but comprehensive synopsis of accumulated knowledge in the theory of anaerobic digestion, as well as an overview of previous research and future directions and opportunities of the AD technology. Achieving a sustainable energy system requires comprehensive reforms in not just economic, social and policy aspects, but also in all technical aspects, which represents one of the most crucial future investments for anaerobic digestion systems.
  •  
29.
  • Dahlquist, Erik, 1951-, et al. (author)
  • Comparison of Gas Quality from Black Liquor and Wood Pellet Gasification Using Modelica Simulation and Pilot Plant Results
  • 2017
  • In: 8th International Conference on Applied Energy, ICAE 2016; Beijing; China; 8 October 2016 through 11 October 2016. - Amsterdam : Elsevier. ; 105, s. 992-998, s. 992-998
  • Conference paper (peer-reviewed)abstract
    • There is a potential to integrate biomass gasification with pulp & paper and CHP plants in order to complement the existing systems with production of chemicals, such as methane, hydrogen, and methanol etc. To perform system analysis of such integration, it is important to gain knowledge of relevant input data on expected synthesis gas composition by gasifying different types of feed stock. In this paper, the synthesis gas quality from wood pellets gasification (WPG) has been compared with black liquor gasification (BLG) through modeling and experimental results at pilot scale. In addition, the study develops regression models like Partial Least Squares (PLS) made from the experimental data. The regression models are then combined with dynamic models developed in Modelica for the investigation of dynamic energy and material balances for integrated plants. The data presented in this study could be used as input to relevant analysis using e.g. ASPEN plus and similar system analysis tools.
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30.
  • Dahlquist, Erik, 1951-, et al. (author)
  • Experimental and numerical investigation of pellet and black liquor gasification for polygeneration plant
  • 2017
  • In: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 204, s. 1055-1064
  • Journal article (peer-reviewed)abstract
    • It is vital to perform system analysis on integrated biomass gasification in chemical recovery systems in pulp and paper and heat and power plants for polygeneration applications. The proposed integration complements existing pulp and paper and heat and power production systems with production of chemicals such as methane and hydrogen. The potential to introduce gasification-based combined cycles comprising gas turbines and steam turbines to utilize black liquors and wood pellets also merits investigation. To perform such analysis, it is important to first build knowledge on expected synthesis gas composition by gasifying at smaller scale different types of feed stock. In the present paper, the synthesis gas quality from wood pellets gasification has been compared with black liquor gasification by means of numerical simulation as well as through pilot-scale experimental investigations. The experimental results have been correlated into partial least squares models to predict the composition of the synthesis gas produced under different operating conditions. The gas quality prediction models are combined with physical models using a generic open-source modelling language for investigating the dynamic performance of large-scale integrated polygeneration plants. The analysis is further complemented by considering potential gas separation using modern membrane technology for upgrading the synthesis gas with respect to hydrogen content. The experimental data and statistical models presented in this study form an important literature source for future use by the gasification and polygeneration research community on further integrated system analysis.
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31.
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32.
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33.
  • Farooq, U., et al. (author)
  • A step forward towards synthesizing a stable and regeneratable nanocomposite for remediation of trichloroethene
  • 2018
  • In: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 347, s. 660-668
  • Journal article (peer-reviewed)abstract
    • Synthesizing supported heterogeneous catalysts is always considered as a persistent approach for degradation of contaminants. However, the stability of these nanocomposites and improvement of process conditions influencing target pollutants degradation are still limited. Herein, on the basis of self-adhesive nature of polydopamine (PDA) and its strong electrostatic interaction with metallic ions, we synthesized a facile, stable, magnetically separable, and environmentally benign PDA decorated, reduced graphene oxide (rGO) supported Fe nanocatalyst (PDA@Fe/rGO). The effects of process variables (pH, PDA@Fe/rGO, and persulphate (PS) dose) on the degradation performance of trichloroethene (TCE), a model chlorinated organic pollutant selected in this study, were investigated. PDA not only encapsulated the host Fe/rGO magnetic particles but also exhibited high magnetization. PDA wrapping tremendously enhanced the thermal stability of nanocatalyst with just 24.1% weight loss at elevated temperature compared to solo Fe/rGO (40.2%). Moreover, TCE degradation mechanism was interpreted by ESR and radical scavenger tests, validating OH[rad], SO4 [rad]− and O2 [rad]− radicals being responsible for TCE degradation. Considering its eminent catalytic activity, simple synthesis approach and excellent kinetics, this recyclable and improved PDA assisted Fe/rGO nanocatalyst further opens a door for practical implementation in the field of contaminated groundwater remediation. 
  •  
34.
  • Farooq, U., et al. (author)
  • Efficient transformation in characteristics of cations supported-reduced graphene oxide nanocomposites for the destruction of trichloroethane
  • 2017
  • In: Applied Catalysis A. - : Elsevier B.V.. - 0926-860X .- 1873-3875. ; 544, s. 10-20
  • Journal article (peer-reviewed)abstract
    • Experiments were conducted to investigate the use of graphene-oxide supported metallic nanocomposites for improving the degradation of trichloroethane (TCA) by sodium percarbonate (SPC). Two methods of production, chemical reduction (CR) and solvo-thermal (ST), were tested for preparation of single (Fe) and binary (Fe-Cu) nanocomposites supported by reduced graphene oxide (rGO). A variety of analytical techniques including N2 adsorption Brunauer-Emmett-Teller (BET), x-ray diffraction (XRD), fourier-transfrom infrared spectroscopy (FTIR), and transmisison electron microscopy (TEM) were applied to characterize the physicochemical and microstructural properties of the synthesized nanocomposites. The characterization indicated that the CR method produced nanocomposites that comprised only mesoporous structure. Conversely, both micro and mesoporous structures were present for samples produced with the ST method. The synthesized single and bimetallic composites produced from the ST method showed higher surface areas, i.e. 93.6 m2/g and 119.2 m2/g as compared to the ones synthesized via the CR method, i.e. 13.8 m2/g and 38.0 m2/g respectively. The results of FTIR and XRD analyses confirmed that the ST method produced highly crystalline nanocomposites. SEM and TEM analysis validated that metallic particles with definite morphology well distributed on the surface of rGO. X-ray photoelectron spectroscopy (XPS) analysis confirmed the homogeneity nanocomposites and occurrence of variation in copper oxidation states during degradation process. EDS mapping validate the homogeneous distribution of Cu and Fe at reduced graphene oxide surface. The Fe-Cu/rGO (ST) activated SPC system effectively degraded TCA (92%) in 2.5 h at low nanocomposite dose compared to the Fe-Cu/rGO (CR) and only Fe, for which the maximum degradation efficiencies achieved were 81% and 34%. In conclusion, excellent catalytic characteristics were observed for the ST-synthesized single and bimetallic (Fe/rGO, Fe-Cu/rGO) catalysts. These catalysts were successful in improving the degradation of TCA via activated SPC. 
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35.
  • Hashemzehi, Mozhgan, et al. (author)
  • A Comprehensive Review of Nanocellulose Modification and Applications in Papermaking and Packaging : Challenges, Technical Solutions, and Perspectives
  • 2022
  • In: BioResources. - : NC State University. - 1930-2126. ; 7:2, s. 3718-3780
  • Journal article (peer-reviewed)abstract
    • The increasing usage of petroleum-based compounds has prompted numerous environmental concerns. Consequently, there has been a steady rise in research on the synthesis of useful materials from natural sources. Paper technologists are seeking environmentally acceptable dry end and wet end additives. Among the bio-based resources available, nanocellulose is a popular sustainable nanomaterial additive in the paper industry because of its high strength, high oxygen barrier performance, low density, great mechanical properties, and biocompatibility. NC’s extensive hydroxyl groups provide a unique possibility to dramatically modify the hydrophilicity and charge of the surface in order to improve their potential applications in the paper industry. The current paper reviews two series of surface modifications, each with various subcategories, depending on why modified nanocellulose is added in the paper production: to improve barrier properties or to improve mechanical properties of packaging materials. The methods presented in this study use the minimum amount of chemically hazardous solvents to have the least impact on the environment. This review focuses on modifications of nanocellulose and their subsequent application in the papermaking. The knowledge and the discussion presented in this review will form a literature source for future use by various stakeholders and the sustainable paper manufacturers.
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36.
  • Inayat, A., et al. (author)
  • Parametric Study for Production of Dimethyl Ether (DME) As a Fuel from Palm Wastes
  • 2017
  • In: Energy Procedia. - Amsterdam, Netherlands : Elsevier Ltd. - 1876-6102. ; , s. 1242-1249
  • Conference paper (peer-reviewed)abstract
    • Dimethyl Ether (DME) has been getting numerous attention as it's potential as the second generation bio-fuel. Traditionally DME is produced from the petroleum based stock which involves two steps of synthesis (methanol synthesis from the syngas and DME synthesis from methanol). DME synthesis via single step is one of the promising methods that has been developed. In Malaysia, due to the abundance of oil palm waste, it is a good candidate to be used as a feedstock for DME production. In this paper, single step process of DME synthesis was simulated and investigated using the Aspen HYSYS. Empty Fruit Bunch (EFB) from palm wastes has been taken as the main feed stock for DME synthesis. Four parameters (temperature, pressure, steam/biomass ratio and oxygen/biomass ratio) have been studied on the H2/CO ratio and DME yield. The results showed that optimum H2/CO ratio of 1.0 has been obtained when having an oxygen to biomass ratio (O/B) of 0.37 and steam to biomass ratio (S/B) of 0.23. The increment in the steam to biomass ratio increased the production of DME while the increment in oxygen to biomass ratio will cause reduction in DME production. © 2017 The Authors.
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37.
  • Moustakas, Konstantinos, et al. (author)
  • Energy and resource recovery through integrated sustainable waste management
  • 2020
  • In: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 261, s. 1-4
  • Journal article (peer-reviewed)abstract
    • This editorial is prepared for the Applied Energy Journal as a Virtual Special Issue (VSI) and it overviews the research work presented at the NAXOS 2018 6th International Conference on Sustainable Solid Waste Management, held from 13th to 16th June 2018 in Naxos Island, Greece. The research articles presented in VSI highlight the recent developments in waste valorisation for the recovery of energy, fuels and value-added products. They also cover the primary hurdles and potential solutions moving towards more sustainable society. This editorial not only presents the overall summary of the extended research papers from NAXOS 2018, but also provides an overview of the current trends and developments in the fields of waste management, waste valorization, and energy production systems. The articles published in this VSI cover a wide range of topics, including energy recovery from waste, waste to energy technologies, sustainable energy systems, anaerobic digestion, thermal arc plasma gasification, microalgal-based biorefinery, waste management, modelling of advanced gasification systems, waste valorization, and microbial fuel cell technology. 10 manuscripts, out of total 21 extended mansucripts invited, were accepted for publication in the Applied Energy Journal through peer review process conducted by the expert reviewers in the relevant fields with the aid of the guest editors.
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38.
  • Naqvi, Muhammad, 1983-, et al. (author)
  • Bio-refinery system in a pulp mill for methanol production with comparison of pressurized black liquor gasification and dry gasification using direct causticization
  • 2012
  • In: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 90:1, s. 24-31
  • Journal article (peer-reviewed)abstract
    • Black liquor gasification (BLG) for bio-fuel or electricity production at the modern pulp mills is a field in continuous evolution and the efforts are considerably driven by the climate change, fuel security, and renewable energy. This paper evaluates and compares two BLG systems for methanol production: (i) oxygen blown pressurized thermal BLG; and (ii) dry BLG with direct causticization, which have been regarded as the most potential technology candidates for the future deployment. A key objective is to assess integration possibilities of BLG technologies with the reference Kraft pulp mill producing 1000 air dried tonnes (ADt) pulp/day replacing conventional recovery cycle. The study was performed to compare the systems’ performance in terms of potential methanol production, energy efficiency, and potential CO2 reductions. The results indicate larger potential of black liquor conversion to methanol from the pressurized BLG system (about 77 million tonnes/year of methanol) than the dry BLG system (about 30 million tonnes/year of methanol) utilizing identical amount of black liquor available worldwide (220 million tDS/year). The potential CO2 emissions reduction from the transport sector is substantially higher in pressurized BLG system (117 million tonnes/year CO2 reductions) as compared to dry BLG system (45 million tonnes/year CO2 reductions). However, the dry BLG system with direct causticization shows better results when considering consequences of additional biomass import. In addition, comparison of methanol production via BLG with other bio-refinery products, e.g. hydrogen, dimethyl ether (DME) and bio-methane, has also been discussed.
  •  
39.
  • Naqvi, Muhammad, 1983- (author)
  • Bio-refinery system integrated with pulp and paper mills using black liquor gasification
  • 2010
  • Licentiate thesis (other academic/artistic)abstract
    • Mitigation of climate change and energy security are major driving forces for increased biomass energy utilization. The pulp and paper industry consumes a large proportion of biomass worldwide that include bark, wood residues, and black liquor. Due to the fact that modern pulp and paper industries have established infrastructure for handling and processing biomass, it is possible to lay foundation for future gasification based bio-refineries to co-produce electricity, chemicals or bio-fuels together with pulp and paper products. There is a potential to export electricity or bio-fuels by improving today’s existing chemical pulp and paper mills integrating gasification technology. The present study evaluates the energy conversion performance of integrated black liquor gasification (BLG) within the chemical pulp mills in comparison with conventional pulp mill energy system. The objective is to investigate and compare various BLG technologies and bio-fuel production routes. The comparison is performed to identify the advantageous route based on system performance indicators e.g. bio-fuel production potential, fuel to product efficiency (FTPE), biomass import, overall system thermal energy efficiency, on-site CO2 reduction using carbon capture, and potential CO2 offsets from bio-fuel use in transport sector. The study on a variety of BLG configurations shows promising results for potential bio-fuel production offering significant contributions toward fossil fuel savings, emission reductions, and improved energy security. Methanol, synthetic natural gas (SNG) and dimethyl ether (DME) show promising features as potential fuel candidates. The comparative results show significantly larger bio-fuel production potential of black liquor conversion to SNG from catalytic hydrothermal gasification than DME, methanol or SNG production from the dry BLG (DBLG) and Chemrec BLG (CBLG) systems. The energy ratio of SNG production from the CHG system is higher than DME and methanol in the CBLG and the DBLG systems. When considering consequences of incremental biomass import, the DBLG system is far better than the CBLG and the CHG systems mainly due to the elimination of the lime kiln. Considerable reduction of on-site CO2 emissions could be achieved using CO2 capture and storage in the pulp mills. The CHG and the CBLG systems shows better performance results than the DBLG system comparing potential CO2 emissions offset from bio-fuels replacing fossil fuels.
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40.
  • Naqvi, Muhammad, 1983-, et al. (author)
  • Bio-refinery system of DME or CH4 production from black liquor gasification in pulp mills
  • 2010
  • In: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 101:3, s. 937-944
  • Journal article (peer-reviewed)abstract
    • There is great interest in developing black liquor gasification technology over recent years for efficient recovery of bio-based residues in chemical pulp mills. Two potential technologies of producing dimethyl ether (DIME) and methane (CH4) as alternative fuels from black liquor gasification integrated with the pulp mill have been studied and compared in this paper. System performance is evaluated based on: (i) comparison with the reference pulp mill, (ii) fuel to product efficiency (FTPE) and (iii) biofuel production potential (BPP). The comparison with the reference mill shows that black liquor to biofuel route will add a highly significant new revenue stream to the pulp industry. The results indicate a large potential of DME and CH4 production globally in terms of black liquor availability. BPP and FTPE of CH4 production is higher than DME due to more optimized integration with the pulping process and elimination of evaporation unit in the pulp mill.
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41.
  • Naqvi, Muhammad, 1983-, et al. (author)
  • Black liquor gasification integrated in pulp and paper mills : A critical review
  • 2010
  • In: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 101:21, s. 8001-8015
  • Research review (peer-reviewed)abstract
    • Black liquor gasification (BLG) has potential to replace a Tomlinson recovery boiler as an alternative technology to increase safety, flexibility and energy efficiency of pulp and paper mills. This paper presents an extensive literature review of the research and development of various BLG technologies over recent years based on low and high temperature gasification that include SCA-Billerud process, Manufacturing and Technology Conversion International (MTCI) process, direct alkali regeneration system (DARS), BLG with direct causticization, Chemrec BLG system, and catalytic hydrothermal BLG. A few technologies were tested on pilot scale but most of them were abandoned due to technical inferiority and very fewer are now at commercial stage. The drivers for the commercialization of BLG enabling bio-refinery operations at modern pulp mills, co-producing pulp and value added energy products, are discussed. In addition, the potential areas of research and development in BLG required to solve the critical issues and to fill research knowledge gaps are addressed and highlighted. (c) 2010 Elsevier Ltd. All rights reserved.
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42.
  • Naqvi, Muhammad, 1983-, et al. (author)
  • Energy conversion performance of black liquor gasification to hydrogen production using direct causticization with CO2 capture
  • 2012
  • In: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 110, s. 637-644
  • Journal article (peer-reviewed)abstract
    • This paper estimates potential hydrogen production via dry black liquor gasification system with direct causticization integrated with a reference pulp mill. The advantage of using direct causticization is elimination of energy intensive lime kiln. Pressure swing adsorption is integrated in the carbon capture process for hydrogen upgrading. The energy conversion performance of the integrated system is compared with other bio-fuel alternatives and evaluated based on system performance indicators. The results indicated a significant hydrogen production potential (about 141MW) with an energy ratio of about 0.74 from the reference black liquor capacity (about 243.5MW) and extra biomass import (about 50MW) to compensate total energy deficit. About 867,000tonnes of CO2 abatement per year is estimated i.e. combining CO2 capture and CO2 offset from hydrogen replacing motor gasoline. The hydrogen production offers a substantial motor fuel replacement especially in regions with large pulp and paper industry e.g. about 63% of domestic gasoline replacement in Sweden.
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43.
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44.
  • Naqvi, Muhammad Raza, 1983-, et al. (author)
  • Biorefinery : Production of Biofuel, Heat, and Power Utilizing Biomass
  • 2015
  • In: Handbook of Clean Energy Systems. - United States : WILEY.
  • Book chapter (peer-reviewed)abstract
    • The world’s energy consumption is projected to increase rapidly that will cause depletion of known fossil fuel resources, global warming and threat to future energy security. Biomass is likely to play a significant role in the future energy systems replacing conventional fuels due to strict regulations for reducing greenhouse gas (GHG) emissions as well as contributing as additional resource in the global energy mix. Biomass is processed in a bio-refinery facility for polygeneration of bio-energy products such as biofuels, heat, and power. Polygeneration system can be categorized based on various process routes producing electricity or biofuels or even providing only heat e.g. biomass gasification system, integrated biogas production with combined heat and power by treating organic waste, tri-generation systems etc. The successful commercialization of bio-refinery systems for polygeneration require pilot plants to demonstrate improvements in energy efficiency,  substantial biofuel, heat and power production potential from biomass together with reduced cost. From the sustainability perspective, bio-refinery systems show numerous economic, social and environmental benefits including diversification in biomass resources and bio-energy products.
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45.
  • Naqvi, Muhammad Raza, 1983-, et al. (author)
  • First-Generation Biofuels
  • 2015
  • In: HANDBOOK OF CLEAN ENERGY SYSTEMS. - UNITED STATES : John Wiley & Sons.
  • Book chapter (peer-reviewed)abstract
    • Global energy demand is primarily dependent on the fossil fuel resources and the energy consumption is growing significantly that will cause increased concentration of greenhouse gases (GHG) in the atmosphere and depletion of known non-renewable energy resources that will cause threat to future energy security. The fossil resources are regarded as un-sustainable in terms of economy, ecology and environmental perspective. The increased utilization of biomass can play a significant role in replacing conventional fossil-based fuels and reducing emissions due to strict regulations for reducing greenhouse gas (GHG) emissions. Biomass based fuels can contribute as additional energy resource in the global energy mix. This chapter has discussed first generation biofuel, concept of bio-refineries, first generation feedstock derived bio-fuels, global first generation biofuel producing countries/regions and major sustainability challenges. The most common first generation biofuels include bio-ethanol, bio-diesel and bio-gas derived mainly from corn, sugarcane, soybean, vegetable oil, palm oil, wastes etc. From the sustainability perspective, first generation biofuels face numerous sustainability challenges including food and fuel competition, change in land-use, potential increased GHG emissions due to fossil fuel utilization in the upstream processes. First generation biofuels appears unsustainable because of the potential stress that their production places on food commodities. The economic aspects of first generation biofuel largely depend upon the type of feedstock and region where the feedstock have been cultivated and produced. Food prices will be affected due to increased production of energy crops that potentially compete with food crops for land use. In addition, the substantial production of biomass and conversion of biomass feedstock to biofuel may create new jobs and increase revenue from the agricultural sector.
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46.
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47.
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48.
  • Naqvi, Muhammad, 1983-, et al. (author)
  • Synthetic natural gas (SNG) production at pulp mills from a circulating fluidized bed black liquor gasification process with direct causticization
  • 2010
  • In: Proceedings of the 23rd International Conference on Efficiency, Cost, Optimization, Simulation, and Environmental Impact of Energy Systems, ECOS 2010. - : Åbo Akademi University Press. - 9781456303112 ; , s. 83-91
  • Conference paper (peer-reviewed)abstract
    • Synthetic natural gas (SNG) production from black liquor gasification (BLG) replacing conventional recovery cycle at chemical pulp mills is an attractive option to reduce CO2 emissions and replace fossil natural gas. This paper evaluates the potential of SNG production from a circulating fluidized bed BLG process with direct causticization by investigating synthesis gas composition, purity requirements for SNG and process integration with the reference pulp mill producing 1000 air dried tonnes (ADt) of pulp per day. The objective of this study is to estimate the integrated process efficiency from black liquor (BL) conversion to SNG and to quantify the differences in overall process efficiencies of various bio-refinery options. The models include a BLG Island including BL gasifier, synthesis gas cooling and cleaning unit, methanation with SNG upgrading and a power boiler. The result indicates a large potential of SNG production from BL but at a cost of additional biomass import to compensate energy deficit in terms of BL conversion to SNG. In addition, the study shows a significant CO2 abatement when CO2 capture is carried out in SNG upgrading and also reducing CO2 emissions when SNG potentially replaces fossil natural gas.
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49.
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50.
  • Rafique, Asia, et al. (author)
  • Design and Modeling of a Fuel Cell System Using Biomass Feedstock as a Biofuel
  • 2020
  • In: Fuel Cells. - : Wiley. - 1615-6846 .- 1615-6854. ; 20:1, s. 89-97
  • Journal article (peer-reviewed)abstract
    • This paper aims to model ceramic fuel cell system based on low-temperature planar solid oxide fuel cell (SOFC) different biogases fuels from multiple biomasses, that is, animal waste, redwood, rice husk and sugar cane. Biomass is a better choice for the generation of energy globally. Therefore, there is a focus on the most available biomass resources in the country that can be used as clean energy sources. This developed model is designed by thermodynamic analysis and electrochemical calculations using MATLAB. The designed model is a lumped parameter model based on the steady-state one-dimensional flow. In this model, all calculated power and flow rate values were kept as positive values. Also, the system is considered to be free of leaks, and heat loss is neglected. The operating temperature and pressure are assumed to be 500–700 °C and the partial pressure is set at three different pressures; P1 (1 bar), P2 (2 bar), and P3 (3 bar), respectively, and fuel utilization factor is 80%. It is observed that the best performance is obtained with animal-waste based biogas at 700 °C and P3 (3 bar).
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